![Examples DKSi [mol-%] EDB [mol-%] DPI [mol-%] Δ R H [kJ/mol] t hmax [min]](https://www.researchgate.net/profile/Joachim-Klee/publication/316477637/figure/tbl4/AS:954171746439174@1604503680996/Examples-DKSi-mol-EDB-mol-DPI-mol-D-R-H-kJ-mol-t-hmax-min_Q320.jpg)
Content uploaded by Joachim E. Klee
Author content
All content in this area was uploaded by Joachim E. Klee on Nov 04, 2020
Content may be subject to copyright.
Content uploaded by Joachim E. Klee
Author content
All content in this area was uploaded by Joachim E. Klee on Apr 26, 2017
Content may be subject to copyright.
Note: Within nine months of the publication of the mention of the grant of the European patent in the European Patent
Bulletin, any person may give notice to the European Patent Office of opposition to that patent, in accordance with the
Implementing Regulations. Notice of opposition shall not be deemed to have been filed until the opposition fee has been
paid. (Art. 99(1) European Patent Convention).
Printed by Jouve, 75001 PARIS (FR)
(19)
EP 3 359 118 B1
*EP003359118B1*
(11) EP 3 359 118 B1
(12) EUROPEAN PATENT SPECIFICATION
(45) Date of publication and mention
of the grant of the patent:
29.01.2020 Bulletin 2020/05
(21) Application number: 16778051.9
(22) Date of filing: 07.10.2016
(51) Int Cl.:
A61K 6/083 (2006.01) A61K 6/00 (2020.01)
(86) International application number:
PCT/EP2016/074049
(87) International publication number:
WO 2017/060459 (13.04.2017 Gazette 2017/15)
(54) DENTAL COMPOSITION
DENTALE ZUSAMMENSETZUNG
COMPOSITION DENTAIRE
(84) Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB
GR HR HU IE IS IT LI LT LU LV M C MK MT NL NO
PL PT RO RS SE SI SK SM TR
(30) Priority: 08.10.2015 EP 15188969
(43) Date of publication of application:
15.08.2018 Bulletin 2018/33
(73) Proprietor: Dentsply DeTrey GmbH
78467 Konstanz (DE)
(72) Inventors:
• KLEE, Joachim E.
78315 Radolfzell (DE)
• SZILLAT, Florian
78462 Konstanz (DE)
• MAIER, Maximilian
78462 Konstanz (DE)
• RITTER, Helmut
42111 Wuppertal (DE)
• LALEVÉE, Jacques
68200 Mulhouse (FR)
• FIK, Christoph P.
9215 Schönenberg a. d. Thur (CH)
• FOUASSIER, Jean Pierre
68590 St. Hippolyte (FR)
• MORLET-SAVARY, Fabrice
68120 Pfastatt (FR)
• DIETLIN, Céline
68100 Mulhouse (FR)
• BOUZRATI-ZERELLI, Mariem
68100 Mulhouse (FR)
(74) Representative: Dietz, Mirko
Sirona Dental Systems GmbH
Fabrikstraße 31
64625 Bensheim (DE)
(56) References cited:
EP-A1- 0 076 102 WO-A1-2015/144579
US-A1- 2008 277 814 US-A1- 2015 080 490
• MOHAMAD EL-ROZ ET AL: "A search for new
radical sources in photoinitiating systems",
CURRENT TRENDS IN POLYMER SCIENCE,
RESEARCH TRENDS, IN, vol. 15, 1 January 2011
(2011-01-01), pages 1-13, XP008179332, ISSN:
0972-446X cited in the application
EP 3 359 118 B1
2
5
10
15
20
25
30
35
40
45
50
55
Description
Field of the invention
[0001] The present invention relates to a dental composition comprising a specific polymerization initiator system
comprising a compound having a silyl or germanyl group. The present invention also relates the use of the compound
having a silyl or germanyl group for the preparation of a dental composition.
Background of the invention
[0002] The restoration of teeth commonly involves a light curable dental composition containing free-radically polym-
erizable resins. Light curing of a dental composition involves a photoinitiator system generating free radicals upon
exposure to visible light. Free radicals may be typically produced by either of two pathways:
(1) the photoinitiator compound undergoes excitation by energy absorption with subsequent decomposition of the
compound into one or more radicals (Norrish type I), or
(2) the photoinitiator compound undergoes excitation and the excited photoinitiator compound interacts with a second
compound by either energy transfer or a redox reaction to form free radicals from any of the compounds (Norrish
type II).
[0003] In order for a photoinitiator to be useful for use in a dental composition, the quantum yields indicating the
conversion of light radiation to radical formation needs to be high since absorption or shielding of light by further com-
ponents of the dental composition limit the amount of energy available for absorption by the photoinitiators. Accordingly,
only about 70 percent conversion of the polymerizable groups may be expected in a polymerization of a typical dental
composition, whereby the mechanical strength of the polymerized dental composition is less than optimal and unreacted
monomers may leach out of the polymerized dental composition. The leaching monomers may have detrimental effects.
In order to alleviate this problem, multifunctional monomers are frequently used which are more likely to be included in
the polymer network.
[0004] In addition, photoinitiators are required to have a high acid resistance, solubility, thermal stability, and storage
stability when incorporated into a dental composition.
[0005] Finally, given that dental compositions usually contain (meth)acrylate or (meth)acrylamide monomers, free
radical photocuring may be inhibited by the presence of oxygen. Oxygen inhibition is due to the rapid reaction of prop-
agating radicals with oxygen molecules to yield peroxyl radicals which are not as reactive towards carbon-carbon un-
saturated double bonds and therefore do not initiate or participate in any photopolymerization reaction. Oxygen inhibition
may lead to premature chain termination and, therefore, incomplete photocuring. Nevertheless, a certain degree of
oxygen inhibition on the top surface of the adhesive layer is required for the bonding to the adjacent restorative.
[0006] Accordingly, the polymerization initiator system has a critical influence on the quality of the dental material.
Conventionally, camphor quinone optionally in combination with a tertiary amine, or 2,4,6-trimethylbenzoylphenyl phos-
phinate (Irgacure® TPO) are frequently used as photoinitiator system. However, the presence of amines in acrylate-
containing compositions can cause yellowing in the resulting photocured composition, create undesirable odors, and
soften the cured composition because of chain transfer reactions and therefore, often require the use of stabilizers.
Moreover, the use of aromatic amines gives rise to toxicological concerns.
[0007] Furthermore, it is desirable that the light activating the photoinitiator system has a long wavelength in order to
avoid damage of soft tissue during polymerization of the dental composition in the patient’s mouth. Accordingly, the
photoinitiator system is required to contain a chromophoric group efficiently absorbing light of the desired wavelength
in a range of from 400 to 800 nm. However, an increase of the absorption coefficient of the photoinitiator system increases
the coloration of the photoinitiator system and thereby the coloration of the dental composition before light curing.
Accordingly, it is necessary that the chromophoric groups are efficiently destroyed during polymerization so that the
coloration of the initiator system disappears in the polymerized dental composition, the so-called "photo-bleaching". A
destruction of the chromophoric groups during polymerization may also be useful in increasing the depth of cure of the
dental composition since activating light is not shielded from unpolymerized layers of the dental composition by the
photoinitiator system present in polymerized layers covering the unpolymerized layers.
[0008] EP 0 076 102 A1 discloses a photopolymerizable composition comprising an epoxy compound, a curing catalyst
including at least one aluminium compound having at least one organic radical directly bonded to the aluminum atom,
at least one α-ketosilyl compound and at least one photosensitizer selected from the group consisting of benzophenone
compounds and thioxanthone compounds. The photopolymerizable composition may be used in the field of electrical
equipment, e.g. for producing an insulating material, or as a photoresist material.
[0009] EP 1 905 415 A1 discloses dental compositions comprising a polymerizable binder and a photoinitiator con-
EP 3 359 118 B1
3
5
10
15
20
25
30
35
40
45
50
55
taining an acylgermanium compound.
[0010] EP 2 103 297 A1 discloses compositions, among others dental compositions, which comprise at least a po-
lymerizable binder and a polymerization initiator comprising at least an acylgermanium compound. The acylgermanium
compound comprises 2 to 100 acylgermanium moieties, which are linked via a bond or a branched or linear aliphatic,
aromatic or aliphatic-aromatic hydrocarbon residue having a valency corresponding to the number of acylgermanium
moieties. As a reference example, a dental composition is disclosed comprising a polymerization initiator system con-
sisting of benzoyltrimethylgermane, and the polymerizable compounds UDMA and triethyleneglycoldimethacrylate.
[0011] US 2015/0080490 A1 discloses a polymerizable dental composition comprising a photoinitiator mixture which
contains at least one diacylgermanium compound such as bis-(4-methoxybenzoyl)diethylgermanium, at least one α-
diketon such as camphor quinone, and an accelerator.
[0012] WO 2015/144579 A1 discloses a polymerizable dental composition comprising a photoinitiator mixture that
contains an α-diketone photoinitiator compound having a light absorption maximum in the range from 300 to 500 nm
such as camphor quinone, and a coinitiator in the form of a hydride of silicium or germanium.
[0013] EI-Roz M. et al., Current Trends in Polymer Science, 2011, vol. 15, pages 1 to 13 discloses free radical pho-
topolymerisation of an epoxy acrylate monomer in the presence of a photoinitiator system consisting of isopropylthiox-
anthone as photoinitiator in combination with acylsilane compounds, among others methyl(trimethylsilyl)methanone and
methyl(triphenylsilyl)methanone. This document does not disclose dental compositions.
Summary of the invention
[0014] It is the problem of the present invention to provide an improved dental composition comprising one or more
compounds having a polymerizable double bond, which composition provides
-improved polymerization efficiency including a high conversion and good curing rate which may be adapted to
provide a suitable working time of the composition,
-improved depth of cure, and
-absence of coloration problems.
[0015] Moreover, it is the problem of the present invention to provide a use of a specific compound for the preparation
of a dental composition.
[0016] The present invention provides a dental composition comprising
(a) one or more compounds having at least one polymerizable double bond;
(b) a polymerization initiator system comprising
(b1) a compound of the following formula (I):
X-R (I)
wherein
X is a group of the following formula (II):
wherein
M is Si or Ge;
R1 represents a substituted or unsubstituted hydrocarbyl or hydrocarbylcarbonyl group;
R2 represents a substituted or unsubstituted hydrocarbyl or hydrocarbylcarbonyl group;
R3 represents a substituted or unsubstituted hydrocarbyl group; and
R (i) has the same meaning as X, whereby the compound of formula (I) may be symmetrical or unsymmetrical;
EP 3 359 118 B1
4
5
10
15
20
25
30
35
40
45
50
55
or
(ii) is a group of the following formula (III):
wherein
Y represents a single bond, an oxygen atom or a group NR’, wherein R’ represents a substituted or
unsubstituted hydrocarbyl group;
R4 represents a substituted or unsubstituted hydrocarbyl group, a trihydrocarbylsilyl group, a mono(hy-
drocarbylcarbonyl)dihydrocarbylsilyl group or a di(hydrocarbylcarbonyl)monohydrocarbylsilyl group;
or
(iii) when M is Si, R may be a substituted or unsubstituted hydrocarbyl group.
[0017] Furthermore, the present invention provides the use of a compound of the following formula (I):
X-R (I)
wherein
X is a group of the following formula (II):
wherein
M is Si or Ge;
R1 represents a substituted or unsubstituted hydrocarbyl or hydrocarbylcarbonyl group;
R2 represents a substituted or unsubstituted hydrocarbyl or hydrocarbylcarbonyl group;
R3 represents a substituted or unsubstituted hydrocarbyl group; and
R
(i) has the same meaning as X, whereby the compound of formula (I) may be symmetrical or unsymmetrical; or
(ii) is a group of the following formula (III):
wherein
Y represents a single bond, an oxygen atom or a group NR’, wherein R’ represents a substituted or unsub-
stituted hydrocarbyl group;
R4 represents a substituted or unsubstituted hydrocarbyl group, a trihydrocarbylsilyl group, a mono(hydro-
EP 3 359 118 B1
5
5
10
15
20
25
30
35
40
45
50
55
carbylcarbonyl)dihydrocarbylsilyl group or a di(hydrocarbylcarbonyl)monohydrocarbylsilyl group; or
(iii) when M is Si, R may be a substituted or unsubstituted hydrocarbyl group,
for the preparation of a dental composition.
[0018] The present invention is based on the recognition that a dental composition according to the present invention
comprising (b1) a compound of the following formula (I) provides improved polymerization efficiency and high curing
speed, and does not give rise to coloration problems of a dental composition. Accordingly, a relatively large amount of
the dental composition can be photocured with reduced exposure to radiation. Due to the high efficiency of the polym-
erization initiator system (b), the presence of oxygen, or oxygen inhibition, is not a serious detriment during photocuring
of a dental composition according to the present invention.
Brief description of the Figures
[0019]
Figures 1a and 1b show the emission spectra of the irradiation sources used for the irradiation of the photocurable
samples, namely a light emitting diode (LED) centred at 405 nm (M405L2 from ThorLabs; about 1100 mW/cm2) and
a blue dental LED centred at 477 nm (SmartLite® Focus from Dentsply, about 1000 mW/cm2).
Figures 2a and 2b show the UV-VIS absorption spectra of benzoyldiphenylmethylsilane (BDMSi) and benzoyltri-
methylsilane (BTMSi) in acetonitrile.
Figure 3 shows the photopolymerization profiles of bisphenol A-glycidyl methacrylate (Bis-GMA)/ triethyleneglycol
dimethacrylate (TEGDMA) formulations polymerized in samples of 25 mm thickness in laminate upon the exposure
to LED at 405 nm for the following different polymerization initiator systems:
-Curve (1): BDMSI/ ethyldimethylaminobenzoate (EDB) 1%/2% w/w;
-curve (2): BDMSi/ diphenyliodonium hexafluorophosphate (DPI) 1%/2% w/w;
-curve (3): BDMSi/ 2,4,6-tris(trichloromethyl)-1,3,5-triazine 1%/2% w/w;
-curve (4): BDMSi/ DPI/EDB 1%/2%/2% w/w;
-curve (5): BDMSi/ DPI/ EDB 1%/2%/2% w/w after one day aging;
-curve (6): BDMSi/ 2,4,6-tris(trichloromethyl)-1,3,5-triazine / EDB 1%/2%/2% w/w; and
-curve (7): BDMSi/ DPI/ EDB 1%/4%/4% w/w.
Figure 4 shows the photopolymerization profiles of Bis-GMA/TEGDMA formulations polymerized in samples of 30
mm thickness in laminate upon the exposure to LED at 405 nm for the following different polymerization initiator
systems:
-Curve (1): BTMSi 1% w/w;
-curve (2): BTMSi/EDB 1%/4% w/w; and
-curve (3): BTMSi/DPI/EDB 1%/4%/4% w/w.
Figure 5 shows the photopolymerization profiles of Bis-GMA/TEGDMA formulations polymerized in samples of 1.4
mm thickness under air upon the exposure to LED at 405 nm for the following different polymerization initiator systems:
-Curve (1): BDMSi/DPI/EDB 1%/4%/4% w/w; and
-curve (2): BTMSi /DPI/EDB 1%/4%/4% w/w.
Figure 6 shows the photopolymerization profile of a Bis-GMA/TEGDMA formulation polymerized in a sample of 1.4
mm thickness under air in the presence of a BTMSi/Ph3GeH/DPI 2%/2%/2% w/w polymerisation initiator system
upon the exposure to LED at 405 nm. The black curve is the raw data, the grey curve is the smoothed curve of the
raw data.
Figure 7 shows the UV-VIS absorption spectra of BDMSi and camphor quinone (CQ) and matching with the emission
spectrum of SmartLite® Focus.
Figure 8 shows the photopolymerization profiles of BisGMA/TEGDMA formulations polymerized in samples of 30
EP 3 359 118 B1
6
5
10
15
20
25
30
35
40
45
50
55
mm thickness in laminate upon the exposure to dental LED at 477 nm in the presence of the following different
polymerization initiator systems:
-Curve (1): CQ/EDB/DPI 1%/2%/2% w/w; and
-curve (2): CQ/BDMSi/EDB/DPI 1%/2%/2%/2% w/w.
Figure 9 shows the photopolymerization profiles of BisGMA/TEGDMA formulation polymerized in samples of 30 mm
thickness under air upon the exposure to dental LED at 477 nm in the presence of the following different polymerization
initiator systems:
-Curve (1): CQ/GeH/DPI 1%/2%/2% w/w; and
-curve (2): CQ/BDMSi/GeH/DPI 1%/1%/2%/2% w/w.
Figure 10 shows the UV-VIS absorption spectrum of tert-butyl (tertbutyldimethylsilyl)glyoxylate) (DKSi) in toluene.
Figure 11 shows the photopolymerization profiles of Bis-GMA/TEGDMA formulations polymerized in samples of 20
mm thickness in laminate upon the exposure to dental LED at 477 nm for the following different polymerization
initiator systems:
-Curve (1): DKSi/EDB/DPI 2%/1.4%/1.6% w/w
-curve (2): DKSi/EDB 2%/1.4% w/w, and
-curve (3): DKSi 2% w/w.
Figure 12 shows the photopolymerization profiles of Bis-GMA/TEGDMA formulations polymerized in samples of 20
mm thickness under air upon the exposure to dental LED at 477 nm for the following different polymerization initiator
systems:
-Curve (1): DKSi 2% w/w;
-curve (2): DKSi/EDB 2%/1.4% w/w;
-curve (3): DKSi/EDB/DPI 2%/1.4%/1.6% w/w; and
-curve (4): CQ/DKSi/EDB/DPI 1%/2%/1.4%/1.6% w/w.
Figure 13 shows the photopolymerization profile of a Bis-GMA/TEGDMA formulation polymerized in a sample of
1.4 mm thickness under air in the presence of a DKSi/EDB/DPI 2%/1.4%/1.6% w/w polymerisation initiator system
upon the exposure to dental LED at 477 nm.
Figure 14 shows the photopolymerization profiles of 11,14-dioxa-2,9-diazaheptadec-16-enoicacid, 4,4,6,16 (or
4,6,6,16)-tetramethyl-10,15-dioxo-2-[(2-methy)-1-oxo-2-propen-1-yl)oxy]ethyl ester (UDMA) formulations polymer-
ized in samples of 1.4 mm thickness under air upon the exposure to LED at 405 nm for the following different
polymerization initiator systems:
-Curve (1): DKSi 0.5% w/w;
-curve (2): DKSi 1% w/w;
-curve (3): DKSi 2% w/w;
-curve (4): DKSi 3% w/w; and
-curve (5): DKSi 5% w/w.
Figures 15a and 15b show the conversion rate for the photopolymerization of UDMA formulations polymerized in
samples of 1.4 mm thickness under air after 20 seconds exposure to LED at 455 nm and to dental LED at 477 nm.
Figure 16 shows photopolymerization profiles of an UDMA formulation polymerized in a sample of 6 mm thickness
under air in the presence of DKSi (2% w/w) upon the exposure to LED at 455 nm (80 mW/cm2).
Figure 17 shows the final colour of two polymers obtained from the photopolymerization of UDMA in a sample of 6
mm thickness under air in the presence of a DKSi/EDB or a CQ/EDB polymerization initiator system and upon
exposure to LED at 455 nm (80 mW/cm2).
Figure 18 shows the absorption spectrum of a CQ/DKSi polymerization initiator system and the emission spectrum
EP 3 359 118 B1
7
5
10
15
20
25
30
35
40
45
50
55
of SmartLite® Focus.
Figure 19 shows the photopolymerization profiles of UDMA formulations polymerized in a sample of 1.4 mm thickness
under air upon exposure to SmartLite® Focus for the following different polymerization initiator systems:
-Curve (1): CQ (0.5% wt)/EDB(2% wt);
-curve (2): DKSi (0.5% wt)/EDB (2%); and
-curve (3): CQ(0.5% wt)/DKSi(0.5% wt)/EDB(2%).
Figure 20 shows the Fourier transform infrared (FTIR) spectrum of tert-butyl (trimethylgermanyl)glyoxylate (TKGe)
obtained with an BaF2 IR pellet.
Figure 21 shows the photopolymerization profile of UDMA polymerized with 2% w/w tert-butyl (trimethylgerma-
nyl)glyoxylate (TKGe) under air upon the exposure to LED at about 470 nm (300 mW/cm2) with SmartLite® Focus
in samples of a thickness of 1.4 mm.
Figures 22 and 23 show absorption spectra obtained from steady state photolysis of UDMA polymerized with the
photoinitiator 2% w/w bis-(benzoyl) diethylgermane (BBG) (cf. Fig. 22) or DKSi (cf. Fig. 23) under air upon the
exposure to LED at 477 nm with SmartLite® Focus in samples of a thickness of 1.4 mm. The absorption spectra
were recorded at the following different times of irradiation:
-Curve (1): 60 s,
-curve (2): 40 s,
-curve (3): 20 s, and
-curve (4): 0 s.
Figure 24 shows the change of the yellow index in correlation with the irradiation time for the photopolymerization
system described for Figures 22 and 23 for the following different photoinitiators:
-Curve (1): DKSi (2% w/w); and
-curve (2): BBG (2% w/w).
[0020] Figure 25 shows the structural formulae of molecules 1 to 19 for which molecular modelling was carried out.
In the structural formulae, it is indicated which bonds (Si-C=O, Ge-C=O and/or O=C-R) may be cleaved upon exposure
to irradiation.
Detailed description of preferred embodiments
[0021] The term "polymerization" relates to the combining by covalent bonding of a large number of smaller molecules,
such as monomers, to form larger molecules, that is, macromolecules or polymers. The monomers may be combined
to form only linear macromolecules or they may be combined to form three-dimensional macromolecules, commonly
referred to as crosslinked polymers. For example, monofunctional monomers form linear polymers, whereas monomers
having at least two functional groups form crosslinked polymers also known as networks. In case of a higher conversion
rate of the polymerizable monomer, the amount of multifunctional monomers may be reduced or the leaching problem
may be alleviated.
[0022] The terms "curing" and "photocuring" mean the polymerization of functional oligomers and monomers, or even
polymers, into a crosslinked polymer network. Curing is the polymerization of unsaturated monomers or oligomers in
the presence of crosslinking agents.
[0023] The terms "photocurable" and "curable" refer to a dental composition that will polymerize into a crosslinked
polymer network when irradiated for example with actinic radiation such as ultraviolet (UV), visible, or infrared radiation.
[0024] The term "quantum yield" is used herein to indicate the efficiency of a photochemical process. More particularly,
quantum yield is a measure of the probability of the excitation of a particular molecule after absorption of a light quantum.
The term expresses the number of photochemical events per photon absorbed.
[0025] "Actinic radiation" is any electromagnetic radiation that is capable of producing photochemical action and can
have a wavelength of at least 150 nm and up to and including 1250 nm, and typically at least 300 nm and up to and
including 750 nm.
[0026] The term "polymerizable double bound" as used herein in connection with compound(s) (a) and compound(s)
(b4) means any double bond capable of radical polymerization, preferably a carbon-carbon double bond. Examples of
EP 3 359 118 B1
8
5
10
15
20
25
30
35
40
45
50
55
the polymerizable double bond include vinyl, conjugated vinyl, allyl, acryl, methacryl and styryl. More preferably, the
polymerizable double bound is selected from the group consisting of acryl, methacryl and styryl. Acryl and methacryl
may be (meth)acryloyl or (meth)acrylamide. Most preferably, for the compound(s) (a), the polymerizable double bound
is acryl or methacryl, and for the compound (b4), the polymerizable double bond with which groups R5, R6 Ar and L may
be substituted is styryl.
[0027] The term "polymerization initiator system" refers to a system comprising at least (b1) a compound of formula
(I). Optionally, the polymerization initiator system may further comprise at least one compound selected from the group
consisting of (b2) a coinitiator, (b3) electron donor, an iodonium salt, a sulfonium salt and a phosphonium salt, and (b4)
an aromatic tertiary phosphine compound.
[0028] The term "coinitiator" refers to a molecule that produces a chemical change in another molecule such as a
photoinitiator in a photochemical process, or to a photoinitiator other than compound of formula (I). The coinitiator may
be a photoinitiator or an electron donor. The term "photoinitiator" is any chemical compound that forms free radicals
when activated, e. g. by exposure to light or interaction with a coinitiator in a photochemical process. For example, the
compound of formula (I) represents a photoinitiator.
[0029] The term "electron donor" as used herein means a compound which is capable of donating electrons in a
photochemical process. Suitable examples include organic compounds having heteroatoms with electron lone pairs, for
example amine compounds.
[0030] The ordinate axis label "O.D." in Figures 20, 22 and 23 means optical density, which is an arbitrary unit.
[0031] The present invention relates to a dental composition. The dental composition may be a dental restorative or
dental prosthetic composition. More preferably, the dental composition is selected from the group consisting of a dental
adhesive composition, a dental composite composition, a resin modified dental cement, a pit and fissure sealer, a
desensitizer and a varnish. The dental composition may be cured by irradiation of actinic radiation.
[0032] The dental composition comprises (a) one or more compounds having at least one polymerizable double bond.
The one or more compounds having a polymerizable double bond may preferably be polymerizable N-substituted alkyl
acrylic or acrylic acid amide monomers or a (meth)acrylate compounds.
[0033] A polymerizable N-substituted alkyl acrylic or acrylic acid amide monomer may be preferably selected from
compounds of the following formulae (A), (B) and (C):
, wherein R9, R*9, R**9, R***9 independently represent a hydrogen atom, -COOM, a straight chain or branched C1
to C18 alkyl group which may be substituted by a C3-6 cycloalkyl group, a C6-14 aryl or C3-14 heteroaryl group, -COOM,
-PO3M, -O-PO3M2 or -SO3M, a C3 to C18 cycloalkyl group which may be substituted by a C1-16 alkyl group, a C6-14
aryl or C3-14 heteroaryl group, -COOM, -PO3M, -O-PO3M2 or -SO3M, or a C5 to C18 aryl or C3 to C18 heteroaryl
group which may be substituted by -COOM, -PO3M, -O-PO3M2 or -SO3M, R10 and R*10 independently represent a
hydrogen atom, a straight chain or branched C1 to C18 alkyl group or C2 to C18 alkenyl group which may be substituted
by a C3-6 cycloalkyl group, a C6-14 aryl or C3-14 heteroaryl group, -COOM, -PO3M, -O-PO3M2 or -SO3M, a C3 to C18
cycloalkyl group which may be substituted by a C1-16 alkyl group, a C6-14 aryl or C3-14 heteroaryl group, -COOM,
-PO3M, -O-PO3M2 or -SO3M, or a C5 to C18 aryl or C3 to C18 heteroaryl group which may be substituted by -COOM,
-PO3M, -O-PO3M2 or -SO3M,
R11 represents a divalent substituted or unsubstituted organic residue having from 1 to 45 carbon atoms, whereby
said organic residue may contain from 1 to 14 carbonyl groups or heteroatoms selected from oxygen, nitrogen and
sulphur; preferably R11 is a C1 to C18 alkylene group or a C2 to C18 alkenylene group, which may contain 1 to 6
carbonyl groups or heteroatoms selected from oxygen, nitrogen and sulfur, and which may be substituted by a
hydroxyl group, a C6-14 aryl group, -COOM, -PO3M, -O-PO3M2 or -SO3M, wherein in said C1 to C18 alkylene group
and said C2 to C18 alkenylene group, from 1 to 6 -CH2-groups may be replaced by a -N-(C=O)-CRZ=CH2 group
wherein RZ is a hydrogen atom or a C1 to C18 alkyl group, a substituted or unsubstituted C3 to C18 cycloalkyl group,
a substituted or unsubstituted C4 to C18 aryl or heteroaryl group, a substituted or unsubstituted C5 to C18 alkylaryl
or alkylheteroaryl group, a substituted or unsubstituted C7 to C30 aralkyl group, and a substituted or unsubstituted
C2 to C45 mono-, di- or polyether group having from 1 to 14 oxygen atoms,
EP 3 359 118 B1
9
5
10
15
20
25
30
35
40
45
50
55
R12 represents a saturated di- or multivalent substituted or unsubstituted C2 to C18 hydrocarbon group, a saturated
di- or multivalent substituted or unsubstituted cyclic C3 to C18 hydrocarbon group, a di- or multivalent substituted or
unsubstituted C4 to C18 aryl or heteroaryl group, a di- or multivalent substituted or unsubstituted C5 to C18 alkylaryl
or alkylheteroaryl group, a di- or multivalent substituted or unsubstituted C7 to C30 aralkyl group, or a di- or multivalent
substituted or unsubstituted C2 to C45 mono-, di-, or polyether residue having from 1 to 14 oxygen atoms, and
m is an integer, preferably in the range from 1 to 10,
wherein M of any one R6, R*9, R**9, R***9, R10, R*10, R11 and R12, which M are independent from each other, each
represent a hydrogen atom or a metal atom.
[0034] For R6, R*9, R**9 and R***9, the straight chain or branched C1 to C18 alkyl group may e.g. be methyl, ethyl, n-
propyl, i-propyl, n-butyl, isobutyl, tert-butyl, sec-butyl, pentyl or hexyl. For R10 and R*10, the C1-18 alkyl group or C2-18
alkenyl group may e.g. be eth(en)yl, n-prop(en)yl, i-prop(en)yl , n-but(en)yl, isobut(en)yl, tert-but(en)yl sec-but(en)yl,
pent(en)yl or hex(en)yl.
[0035] For R6, R*9, R**9, R***9, R10 and R*10, an aryl group may, for example, be a phenyl group or a naphthyl group,
and a C3-14 heteroaryl group may contain 1 to 3 heteroatoms selected from nitrogen, oxygen and sulfur.
[0036] In formula (B), the dotted bond indicates that R9 and R***9 may be in cis or trans configuration relative to CO.
[0037] Preferably, in formula (B), R9, R*9, R**9 and R**9 independently represent a hydrogen atom, - COOM, a straight
chain or branched C1-16 alkyl group which may be substituted by a C3-6 cycloalkyl group, a C6-14 aryl or C3-14 heteroaryl
group, -COOM, -PO3M, -O-PO3M2 or - SO3M, a C3-6 cycloalkyl group which may be substituted by a C1-16 alkyl group,
a C6-14 aryl or C3-14 heteroaryl group, -COOM, -PO3M, -O-PO3M2 or -SO3M, a C6-14 aryl or C3-14 heteroaryl group which
may be substituted by -COOM, -PO3M, -O-PO3M2 or -SO3M. More preferably, in formula (B), R9, R*9, R**9 and R***9
independently represent a hydrogen atom, a straight chain or branched C1-8 alkyl group which may be substituted by a
C4-6 cycloalkyl group, a C6-10 aryl or C4-10 heteroaryl group, a C4-6 cycloalkyl group which may be substituted by a C1-6
alkyl group, a C6-10 aryl or C4-10 heteroaryl group or a C6-10 aryl group. Even more preferably, R9, R*9, R**9 and R***9
independently represent a hydrogen atom, a straight chain or branched C1-4 alkyl group which may be substituted by a
cyclohexyl group or a phenyl group, or a cyclohexyl group which may be substituted by a C1-4 alkyl group. Most preferably,
R9, R*9, R**9 and R***9 independently represent a hydrogen atom or a straight chain or branched C1-4 alkyl group.
[0038] Preferably, in formula (B), R10 and R*10 independently represent a hydrogen atom, a straight chain or branched
C1-16 alkyl group or C2-16 alkenyl group which may be substituted by a C3-6 cycloalkyl group, a C6-14 aryl or C3-14
heteroaryl group, -COOM, -PO3M, -O-PO3M2 or - SO3M, a C3-6 cycloalkyl group which may be substituted by a C1-16
alkyl group, a C6-14 aryl or C3-14 heteroaryl group, -COOM, -PO3M, -O-PO3M2 or -SO3M, a C6-14 aryl or C3-14 heteroaryl
group which may be substituted by -COOM, -PO3M, -O-PO3M2 or -SO3M. More preferably, R10 and R*16 independently
represent a hydrogen atom, a straight chain or branched C1-10 alkyl or C2- 10 alkenyl group group which may be substituted
by a C4-6 cycloalkyl group, a C6-10 aryl or C4-10 heteroaryl group, a C4-6 cycloalkyl group which may be substituted by
a C1-6 alkyl group, a C6-10 aryl or C4-10 heteroaryl group or a C6-10 aryl group. Even more preferably, R10 and R*10
independently represent is a hydrogen atom, a straight chain or branched C1-10 alkyl group or C2-10 alkenyl group which
may be substituted by a cyclohexyl group or a phenyl group, or a cyclohexyl group which may be substituted by a C1-4
alkyl group. Yet even more preferably, R10 and R*10 represent an unsubstituted C1-10 alkyl group or C2-10 alkenyl group,
still even more preferably an unsubstituted C2-6 alkyl group or C3-6 alkenyl group, and most preferably an ethyl group
or an allyl group.
[0039] Particular preferred mono- or bis- or (meth)acrylamides and poly[(meth) acrylamides] have the following for-
mulae:
EP 3 359 118 B1
10
5
10
15
20
25
30
35
40
45
50
55
EP 3 359 118 B1
11
5
10
15
20
25
30
35
40
45
50
55
[0040] Most preferred are the bis-(meth)acrylamides:
N,N’-diallyl-1,4- bisacrylamido-(2E)-but-2-en (BAABE) having the structural formula
and
N,N’-diethyl-1,3-bisacrylamido-propan (BADEP) having the structural formula
EP 3 359 118 B1
12
5
10
15
20
25
30
35
40
45
50
55
[0041] Other suitable examples of polymerizable compounds having a polymerizable double bond are isopropenyl
oxazoline, vinyl azalactone, vinyl pyrrolidone, styrene, divinylbenzene, urethane acrylates or methacrylates, epoxy acr-
ylates or methacrylates and polyol acrylates or methacrylates.
[0042] A (meth)acrylate compound may be selected from the group of methyl acrylate, methyl methacrylate, ethyl
acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, 2-hydrox-
yethyl acrylate, 2-hydroxyethyl methacrylate (HEMA), hydroxypropyl acrylate, hydroxypropyl methacrylate, tetrahydro-
furfuryl acrylate, tetrahydrofurfuryl methacrylate, glycidyl acrylate, glycidyl methacrylate, the diglycidyl methacrylate of
bis-phenol A ("bis-GMA"), 11,14-dioxa-2,9-diazaheptadec-16-enoicacid, 4,4,6,16 (or 4,6,6,16)-tetramethyl-10,15-di-
oxo-,2-[(2-methyl-1-oxo-2-propen-1-yl)oxy]ethyl ester (UDMA), glycerol mono-and di- acrylate, glycerol mono-and
dimethacrylate, ethyleneglycol diacrylate, ethyleneglycol dimethacrylate, polyethyleneglycol diacrylate (where the
number of repeating ethylene oxide units vary from 2 to 30), polyethyleneglycol dimethacrylate (where the number of
repeating ethylene oxide units vary from 2 to 30 especially triethylene glycol dimethacrylate ("TEGDMA"), neopentyl
glycol diacrylate, neopentylglycol dimethacrylate, trimethylolpropane triacrylate, trimethylol propane trimethacrylate, mo-
no-, di-, tri-, and tetra- acrylates and methacrylates of pentaerythritol and dipentaerythritol, 1,3-butanediol diacrylate,
1,3-butanediol dimethacrylate, 1,4-butanedioldiacrylate, 1,4-butanediol dimethacrylate, 1,6-hexane diol diacrylate, 1,6-
hexanediol dimethacrylate, di-2-methacryloyloxethyl hexamethylene dicarbamate, di-2-methacryloyloxyethyl trimethyl-
hexanethylene dicarbamate, di-2-methacryloyl oxyethyl dimethylbenzene dicarbamate, methylene-bis-2-methacryloxye-
thyl-4-cyclohexyl carbamate, di-2-methacryloxyethyl-dimethylcyclohexane dicarbamate, methylene-bis-2-methacry-
loxyethyl-4-cyclohexyl carbamate, di-1-methyl-2-methacryloxyethyl-trimethyl-hexamethylene dicarbamate, di-1-methyl-
2-methacryloxyethyl-dimethylbenzene dicarbamate, di-1-methyl-2-methacryloxyethyl-dimethylcyclohexane dicar-
bamate, methylene-bis-1-methyl-2-methacryloxyethyl-4-cyclohexyl carbamate, di-1-chloromethyl-2-methacryloxyethyl-
hexamethylene dicarbamate, di-1-chloromethyl-2-methacryloxyethyl-trimethylhexamethylene dicarbamate, di-1-chlo-
romethyl-2-methacryloxyethyl-dimethylbenzene dicarbamate, di-1-chloromethyl-2-methacryloxyethyl-dimethylcy-
clohexane dicarbamate, methylene-bis-2-methacryloxyethyl-4-cyclohexyl carbamate, di-1-methyl-2-methacryloxyethyl-
hexamethylene dicarbamate, di-1-methyl-2-methacryloxyethyl-trimethylhexamethylene dicarbamate, di-1-methyl-2-
methacryloxyethyl-dimethylbenzene dicarbamate, di-1-methyl-2-metha-cryloxyethyl-dimethylcyclohexane dicarbamate,
methylene-bis-1-methyl-2-methacryloxyethyl-4-cyclohexyl carbamate, di-1-chloromethyl-2-methacryloxyethyl-hexame-
thylene dicarbamate, di-1-chloromethyl-2-methacryloxyethyl-trimethylhexamethylene dicarbamate, di-1-chloromethyl-
2-methacryloxyethyl-dimethylbenzene dicarbamate, di-1-chloromethyl-2-methacryloxyethyl-dimethylcyclohexane dicar-
bamate, methylene-bis-1-chloromethyl-2-methacryloxyethyl4-cyclohexyl carbamate, 2,2’-bis(4-methacryloxyphe-
nyl)propane, 2,2’bis(4-acryloxyphenyl)propane, 2,2’-bis[4(2-hydroxy-3-methacryloxy-phenyl)]propane, 2,2’-bis[4(2-hy-
droxy-3-acryloxy-phenyl)propane, 2,2’-bis(4-methacryloxyethoxyphenyl)propane, 2,2’-bis(4-acryloxyethoxyphenyl)pro-
pane, 2,2’-bis(4-methacryloxypropoxyphenyl)propane, 2,2’-bis(4-acryloxypropoxyphenyl)propane, 2,2’-bis(4-methacry-
loxydiethoxyphenyl)propane, 2,2’-bis(4-acryloxydiethoxyphenyl)propane, 2,2’-bis[3(4-phenoxy)-2-hydroxypropane-1-
methacrylate]propane,and 2,2’-bis[3(4-phenoxy)-2-hydroxypropane-1-acryalte]propane, may be mentioned. Other suit-
able examples of polymerizable components are isopropenyl oxazoline, vinyl azalactone, vinyl pyrrolidone, styrene,
divinylbenzene, urethane acrylates or methacrylates, epoxy acrylates or methacrylates and polyol acrylates or meth-
acrylates.
[0043] It is preferred to select polymerizable compounds having a polymerizable double bond with the proviso that
they do not contain ester groups, or at least only ester groups which do not significantly hydrolyze in aqueous media at
pH 3 at room temperature within one month. Thereby, an advantageous stability of an acidic dental composition, that is
a composition having a pH of less than 7, in terms of shelf-life stability of the uncured dental composition as well as
stability after curing in the mouth of a patient is ensured. Therefore, particularly preferred are polymerizable compounds
having a polymerizable double bond which do not comprise an ester group. That is, for acidic dental compostitions,
(meth)acrylates are preferably excluded.
[0044] It is preferred that at least one of the polymerizable compounds having at least one polymerizable double bond
has an acidic group. This acidic group is preferably selected from a carboxylic acid group, a sulfonic acid ester group,
a phosphonic acid ester group and a phosphoric acid ester group.
[0045] Phosphoric acid ester group containing polymerizable compounds having at least one polymerizable double
bond preferably have the following formula (D):
EP 3 359 118 B1
13
5
10
15
20
25
30
35
40
45
50
55
wherein
the moieties Y independent from each other represent a hydrogen atom or
a moiety of the following formulae (Y*), (Y**) or (Y***):
wherein
Z1 is COORα, COSRβ, CON(Rα)2, CONRαRβ, or CONHRα, wherein Rα and Rβ independently represent a hydrogen
atom, a C1-18 alkyl group optionally substituted by a C3-8 cycloalkyl group, an optionally substituted C3-8 cycloalkyl
group, an optionally substituted C4-18 aryl or heteroaryl group, an optionally substituted C5-18 alkylaryl or alkylheter-
oaryl group, or an optionally substituted C7-30 aralkyl group, whereby two Rα residues may form together with the
adjacent nitrogen atom to which they are bound a 5- to 7-membered heterocyclic ring which may contain further
nitrogen atoms or an oxygen atoms, and whereby the optionally substituted groups may be substituted by 1 to 5
C1-5 alkyl group(s);
R13 and R14 independently represent a hydrogen atom, an optionally substituted C1-18 alkyl group, an optionally
substituted C3-18 cycloalkyl group, an optionally substituted C5-18 aryl or heteroaryl group, an optionally substituted
C5-18 alkylaryl or alkylheteroaryl group, an optionally substituted C7-30 aralkyl group, whereby the optionally substi-
tuted groups may be substituted by 1 to 5 C1-5 alkyl group(s);
L* represents an (a+b)-valent organic residue (whereby b is 1 when Y in formula (D) is within the round brackets)
containing 2 to 45 carbon atoms and optionally heteroatoms such as oxygen, nitrogen and sulfur atoms, the carbon
atoms including a + b carbon atoms selected from primary and secondary aliphatic carbon atoms, secondary alicyclic
carbon atoms, and aromatic carbon atoms, each of the a+b carbon atoms linking a phosphate or a moiety of any
one of formula (Y*), (Y**) and (Y***); a is an integer of from 1 to 10, preferably 1 to 5; b is an integer of from 1 to 10,
preferably 1 to 5; provided that at least one Y is not hydrogen. The preparation of such compounds wherein Y = Y*
is known from EP-A 1 548 021.
[0046] Furthermore, the polymerizable monomer having one or more acidic groups may be selected from:
1) phosphonic acid group containing polymerizable acidic compounds of the following formula (E):
wherein
the moiety Y1 represents a moiety of the following formulae (Y1*), (Y1**) or (Y1***):
EP 3 359 118 B1
14
5
10
15
20
25
30
35
40
45
50
55
Z2 independently has the same meaning as defined for Z1;
R15 and R16 independently have the same meaning as defined for R13 and R14;
L1 represents a (c + d) valent organic residue containing 2 to 45 carbon atoms and optionally heteroatoms such
as oxygen, nitrogen and sulfur, the carbon atoms including c + d carbon atoms selected from primary and
secondary aliphatic carbon atoms, secondary alicyclic carbon atoms, and aromatic carbon atoms, each of the
c+d carbon atoms linking a phosphonate or a moiety of any one of formula (Y1*), (Y1**) and (Y1***); and
c and d independently represent integers of from 1 to 10; and/or
2) sulfonic acid group containing polymerizable acidic compounds of the following formula (E):
wherein
the moiety Y2 represents a moiety of the following formulae (Y2*), (Y2**) or (Y2***):
Z3 independently has the same meaning as defined for Z1;
R17 and R18 independently have the same meaning as defined for R13 and R14;
L2 represents an (e + f) valent organic residue containing 2 to 45 carbon atoms and optionally heteroatoms
such as oxygen, nitrogen and sulfur atoms, the carbon atoms including e + f carbon atoms selected from primary
and secondary aliphatic carbon atoms, secondary alicyclic carbon atoms, and aromatic carbon atoms, each of
the e+f carbon atoms linking a sulphonate or a moiety of any one of formula (Y2*), (Y2**) and (Y2***); and e and
f independently represent an integer of from 1 to 10.
[0047] It is preferred to select compounds of formula (D), (E) and (F) with the proviso that they do not contain ester
groups, or at least only ester groups which do not significantly hydrolyze in aqueous media at pH 3 at room temperature
within one month, such as the phosphoric acid ester group of compounds of formula (D). Thereby, an advantageous
stability of an acidic dental composition, that is a composition having a pH of less than 7, in terms of shelf-life stability
of the uncured dental composition as well as stability after curing in the mouth of a patient is ensured. Therefore,
particularly preferred are compounds of formula (D) excluding the moiety of formula Y*** and the moiety of formula Y*
wherein Z1 is COORα or COSRβ, compounds of formula (E) excluding the moiety of formula Y1*** and the moiety of
formula Y1* wherein Z2 is COORα or COSRβ as well as compounds of formula (F) excluding the moiety of formula Y2***
and the moiety of formula Y2* wherein Z3 is COORα or COSRβ.
[0048] From the phosphoric acid ester group containing polymerizable compound having at least one polymerizable
double bond, compounds of formula (D’) characterized by one of the following formulae are particularly preferred:
EP 3 359 118 B1
15
5
10
15
20
25
30
35
40
45
50
55
, wherein Z1 is defined as above, and L* is an optionally substituted alkylene group. More preferably, Z1 is methyl, and
L* is a C4 to C16 alkylene group. Even more preferably, L* is a C8 to C12 alkylene group.
[0049] From the sulfonic acid group containing polymerizable compound having at least one polymerizable double
bond, compounds of formula (XI’) characterized by one of the following formulae are particularly preferred:
[0050] In a particularly preferred embodiment, according to (a), the dental composition according to the present in-
vention contains at least one polymerizable compound having at least one (meth)acryl moiety and optionally at least
one polymerizable compound having a polymerizable double bond and an acidic group, more preferably at least one
polymerizable compound of formula (A), (B) or (C) described above and optionally at least one polymerizable compound
of formula (D), (E) or (F) described above.
[0051] Carboxylic acid group containing polymerizable compounds having at least one polymerizable double bond
may be selected e.g. from acrylic acid and methacrylic acid.
[0052] Preferably, the one or more compounds having a polymerizable double bond each contain one or two radical-
polymerizable groups.
[0053] It is preferable that a blending ratio of the one or more compounds having a polymerizable double bond to the
entire dental composition is 5 to 80% by weight. More preferably, the blending ratio is 10 to 60% by weight.
[0054] The dental composition further comprises (b) a polymerization initiator system comprising (b1) a compound of
formula (I). The dental composition may comprise one or more compound(s) of formula (I).
EP 3 359 118 B1
16
5
10
15
20
25
30
35
40
45
50
55
[0055] The compound (b1) has the following formula (I):
X-R (I).
[0056] In formula (I), X is an acylsilyl or acylgermanyl group of the following formula (II):
[0057] In formula (II), M is Si or Ge, R1 and R2 independently from each other represent a substituted or unsubstituted
hydrocarbyl or hydrocarbylcarbonyl group, and R3 represents a substituted or unsubstituted hydrocarbyl group.
[0058] R of formula (I) may (i) have the same meaning as X, whereby the compound of formula (I) may be symmetrical
or unsymmetrical, (ii) be a group of formula (III), or (iii) when M is Si, R may be a substituted or unsubstituted hydrocarbyl
group.
[0059] The group of formula (III) has the following structural formula:
[0060] In the group of formula (III), Y represents a single bond, an oxygen atom or a group NR’, wherein R’ represents
a substituted or unsubstituted hydrocarbyl group. R4 represents a substituted or unsubstituted hydrocarbyl group, a
trihydrocarbylsilyl group, a mono(hydrocarbylcarbonyl)dihydrocarbylsilyl group or a di(hydrocarbylcarbonyl)mono-hy-
drocarbylsilyl group.
[0061] It was surprisingly found that compounds of formula (I) represent polymerization initiators which are particularly
suitable for dental compositions. With compounds of formula (I), a high polymerization efficiency is attained, and no
coloration problems occur, or in a polymerization system comprising a conventional photoinitiator such as camphor
quinone, coloration is efficiently suppressed. Furthermore, compounds of formula (I) have a light absorption within the
wavelength range typically applied in dental application, they are compatible with the ingredients of dental compositions
and besides, they are considered physiologically harmless.
[0062] In connection with compound of formula (I), the term "substituted" as used herein means that R1, R2, R3, R4
and R’ may be substituted by a substituent selected from the group consisting of halogen atoms, a nitro group, a cyano
group, a hydroxy group, an amino group, C1-6 alkyl groups, C1-6 alkoxy groups and a -NRxRy group wherein Rx and Ry
independently from each other represent a C1-6 alkyl group. Here, illustrative of the halogen atoms can be fluorine,
chlorine, bromine and iodine. The C1-6 alkyl groups are, for example, methyl, ethyl, n-propyl, isopropyl and n-butyl.
Illustrative of the C1-6 alkoxy groups are, for example, methoxy, ethoxy and propoxy. The alkyl moieties in these sub-
stituents may be linear, branched or cyclic. Preferably, the substituent is selected from a chlorine atom, a nitro group,
a C1-4 alkoxy group and a -NRxRy group wherein Rx and Ry independently from each other represent a C1-4 alkyl group.
[0063] If R1, R2 and R3 are substituted, then it is preferred that they are substituted with 1 to 3 substituents, more
preferably with 1 substituent.
[0064] In the compound of formula (I), moieties R1, R2 and R3 may be defined as follow s:
R1 and R2 independently from each other represent a substituted or unsubstituted hydrocarbyl or hydrocarbylcarbonyl
group, and R3 represents a substituted or unsubstituted hydrocarbyl group.
[0065] The hydrocarbyl group may be an alkyl group, a cycloalkyl group, a cycloalkylalkyl group, an arylalkyl group
or an aryl group.
[0066] An alkyl group may be straight-chain or branched C1-20 alkyl group, typically a C1-8 alkyl group. Examples for
a C1-6 alkyl group can include linear or branched alkyl groups having 1 to 6 carbon atoms, preferably 1 to 4 carbon
atoms, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl and n-
hexyl.
[0067] A cycloalkyl group may be a C3-20 cycloalkyl group, typically a C3-8 cycloalkyl group. Examples of the cycloalkyl
group can include those having 3 to 6 carbon atoms, for example, cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl.
EP 3 359 118 B1
17
5
10
15
20
25
30
35
40
45
50
55
[0068] A cycloalkylalkyl group may have 4 to 20 carbon atoms and may include a combination of a linear or branched
alkyl group having 1 to 6 carbon atoms and a cycloalkyl group having 3 to 14 carbon atoms. Examples of the cycloalky-
lalkyl(-) group can for example, include methylcyclopropyl(-) methylcyclobutyl(-), methylcyclopentyl(-), methylcy-
clohexyl(-), ethylcyclopropyl(-), ethylcyclobutyl(-), ethylcyclopentyl(-), ethylcyclohexyl(-), propylcyclopropyl(-), propylcy-
clobutyl(-), propylcyclopentyl(-), propylcyclohexyl(-).
[0069] An arylalkyl(-) group may be a C7-20 arylalkyl(-) group, typically a combination of a linear or branched alkyl
group having 1 to 6 carbon atoms and an aryl(-) group having 6 to 10 carbon atoms. Specific examples of an arylalkyl(-)
group are a benzyl(-) group or a phenylethyl(-) group.
[0070] An aryl group can include aryl groups having 6 to 10 carbon atoms. Examples of the aryl group are phenyl and
naphtyl.
[0071] The hydrocarbylcarbonyl groups of R1 and R2 represent acyl groups (Rorg-(C=O)-) in which the organic residue
Rorg is a hydrocarbyl residue as defined above.
[0072] Compound of formula (I) may contain one or two hydrocarbylcarbonyl groups, that is either one of R1 or R2 is
a hydrocarbylcarbonyl group, or both R1 and R2 are hydrocarbylcarbonyl groups. Preferably, compound of formula (I)
contains one hydrocarbylcarbonyl group.
[0073] Preferably, the hydrocarbylcarbonyl group is an arylcarbonyl group, more preferably a benzoyl group.
Preferably, R1 and R2 are independently selected from the group consisting of a straight chain or branched C1-6 alkyl
group, and a phenyl or benzoyl group which may optionally be substituted by one to three substitutents selected from
halogen atoms, a nitro group, a C1-4 alkoxy group and a -NRxRy group wherein Rx and Ry independently from each
other represent a C1-4 alkyl group, and R3 is a straight chain or branched C1-6 alkyl group or a phenyl group.
[0074] Most preferably, R1 and R2 are independently selected from the group consisting of a straight chain or branched
C1-4 alkyl group, and a phenyl or benzoyl group which may optionally be substituted with one substituent selected from
the group consisting of selected from a halogen atom, a nitro group, a C1-4 alkoxy group and a -NRxRy group wherein
Rx and Ry independently from each other represent a C1-4 alkyl group, and R3 is a straight chain or branched C1-4 alkyl
group.
[0075] In the compound of formula (I), R may have the same meaning as X, whereby the compound of formula (I)
may be symmetrical or unsymmetrical. Alternatively, R may represent a substituted or unsubstituted hydrocarbyl group,
or a group of formula (III). Preferably, if R has the same meaning as X, then compound of formula (I) is unsymmetrical.
If R represents a substituted or unsubstituted hydrocarbyl group, then the hydrocarbyl group has the same meaning as
defined above for R1 and is independently selected therefrom.
[0076] In the group of formula (III) of compound of formula (I), R4 represents a substituted or unsubstituted hydrocarbyl
group, a trihydrocarbylsilyl group, a mono(hydrocarbylcarbonyl)dihydrocarbylsilyl group or a di(hydrocarbylcarbo-
nyl)monohydrocarbylsilyl group.
[0077] If R4 of formula (III) is a trihydrocarbylsilylgroup, a mono(hydrocarbylcarbonyl)-dihydrocarbylsilyl group or a
di(hydrocarbylcarbonyl)monohydrocarbylsilyl group, each of the hydrocarbyl and hydrocarbylcarbonyl groups has the
same meaning as defined for R1, R2 and R3 and is independently selected therefrom.
[0078] In formula (III), R’ has the same meaning as defined for R3 and is independently selected therefrom.
[0079] If M is Si in compound of formula (I), R may be also be a substituted or unsubstituted hydrocarbyl group, wherein
the hydrocarbyl group has the same meaning as defined above for R3 and is independently selected therefrom.
[0080] For example, compounds of formula (I) wherein R has the same meaning as X and which are symmetrical may
be have the following structural formulae:
For example, compounds of formula (I) wherein R represents a group of formula (III) wherein Y is a bond, an oxygen
atom or a NR’ group, and R4 represents a substituted or unsubstituted hydrocarbyl group may have the following structural
formulae:
EP 3 359 118 B1
18
5
10
15
20
25
30
35
40
45
50
55
For example, compounds of formula (I) wherein R represents a group of formula (III) wherein R4 represents a trihydro-
carbylsilyl group have the following structural formulae:
For example, compounds of formula (I) wherein M is Si and R represents a substituted or unsubstituted hydrocarbyl
group, may have the following structural formulae:
EP 3 359 118 B1
19
5
10
15
20
25
30
35
40
45
50
55
[0081] Preferably, compound of formula (I) is selected from the group consisting of:
wherein compounds of formula (I) with M = Si are particularly preferred.
[0082] Most preferably, compound of formula (I) is selected from the group consisting of: compound of formula (I) is
selected from the group consisting of:
EP 3 359 118 B1
20
5
10
15
20
25
30
35
40
45
50
55
wherein it is particularly preferred that M = Si.
[0083] In case the dental composition is in the form of an acidic composition, that is a composition having a pH of less
than 7, depending on the composition’s pH level, it is preferred to select compounds of formula (I) with the proviso that
they do not contain ester groups, or at least only ester groups which do not significantly hydrolyze in aqueous media at
pH 3 at room temperature within one month. Thereby, an advantageous stability of an acidic dental composition, that is
a composition having a pH of less than 7, in terms of shelf-life stability of the uncured dental composition as well as
stability after curing in the mouth of a patient is ensured. Therefore, for acidic dental compositions, particularly preferred
are compounds of formula (I) excluding R being a group of formula (III) in which Y is an oxygen atom.
[0084] Furthermore, since the acylsilyl moiety (-C(=O)-Si-) might be sensitive to basic conditions, that is a pH higher
than 7, it is preferred to suitably select a pH value of the composition being higher than 7 with the proviso that the acylsilyl
moiety is not cleaved in aqueous media at the selected basic pH at room temperature within one month.
[0085] The compound of the formula (I) may be a known compound which is commercially available or a may be
prepared according to published procedures.
[0086] The compound of formula (I) wherein M is Si and R represents a substituted or unsubstituted hydrocarbyl group
may for example be readily prepared by means of a one-step Pd-catalyzed reaction with a disilane as described e.g. by
Yamamoto K. et al., J. Tetrahedron Lett., 1980, vol. 21, pages 1653 to 1656:
[0087] In Scheme 1, the reaction is exemplary depicted with hexamethylsilan as the disilane, whereby a compound
of formula (I) wherein R1, R2 and R3 represent a methyl group is obtained. It is understood that R1, R2 and R3 can be
varied by applying disilanes having hydrocarbon substituents other than methyl.
[0088] The compound of formula (I) wherein R represents a group of formula (III) in which Y is an oxygen atom and
R4 represents a hydrocarbyl group may for example be prepared by a three-step synthesis as described by Nicewicz
D.A. et al. in Org. Synth., 2008, 85, pages 278 to 286. In this three-step synthesis, an acetoacetate is converted to an
azide compound, which is then reacted with a trihydrocarbylsilyltrifluoromethane-sulfonate to obtain a trihydrocarbylsi-
lyldiazoacetate, which is finally reacted with potassium peroxymonosulfate to arrive at the target compound:
EP 3 359 118 B1
21
5
10
15
20
25
30
35
40
45
50
55
[0089] In Scheme 2, the reaction is exemplary depicted for obtaining a compound of formula (I) wherein in X of formula
(II), R1 and R2 represent a methyl group, and R3 represents a tert-butyl group. It is understood that R1, R2 and R3 can
be varied by applying a trihydrocarbylsilyltrifluoromethane-sulfonate other than t-BuMeSiOSO2CF3.
Alternatively, compounds of formula (I) wherein M is Si, R represents a group of formula (III) and Y represents an oxygen
atom may be prepared by a single-pot three-component coupling reaction of a silylglyoxylate, a terminal alkyne and an
aldehyde in the presence of Znl2 and Et3N as described by Nicewicz D.A. in J. Am. Chem. Soc., 2005, 127 (17), pages
6170 to 6171. Further syntheses of silylglyoxylate compounds are described e.g. by Boyce G.R. et al. in J. Org. Chem.,
2012, 77 (10), pages 4503 to 4515 and Boyce G.R. et al. in Org. Lett., 2012, 14 (2), pages 652 to 655.
For example, the following compounds of formula (I) are known and commercially available, and their Chemical Abstracts
(CAS) No. is given in brackets: benzoyltriphenylsilane (1171-49-9), benzoyltrimethylsilan (5908-41-8), 1-[(trimethylsilyl)
carbonyl]-naphthalene (88313-80-8), 1-methoxy-2-[(trimethylsilyl)-carbonyl]- benzene (107325-71-3), (4-chlorobenzoyl)
(triphenyl) silane (1172-90-3), (4-nitrobenzoyl) (triphenyl) silane (1176-24-5), (methyldiphenylsilyl)phenyl-methanone
(18666-54-1), (4-methoxybenzoyl) triphenylsilan (1174-56-7) and tert-butyl (tert-butyldimethylsilyl)glyoxylate
(852447-17-7).
[0090] The compound of formula (I) wherein M of X is Ge and R represents a group of formula (III) in which Y is an
oxygen atom and R4 represents a hydrocarbyl group may for example be prepared by a two step synthesis starting from
a trihydrocarbylgermanyltrifluoromethane-sulfonate such as trimethylgermane triflate. Such trimethylgermane triflate
may be prepared starting from commercially available chlorotrimethylgermane as described by S.P. Mallela et al. in J.
Fluorine Chem., 1989, vol. 44, issue 2, pages 309 to 328. As shown in Scheme 3 below, the trihydrocarbylgermanyltri-
fluoromethane-sulfonate and an azide compound are reacted to obtain a trihydrocarbylgermanyldiazoacetate, which is
reacted with oxone (potassium peroxymonosulfate) to arrive at the target compound:
EP 3 359 118 B1
22
5
10
15
20
25
30
35
40
45
50
55
[0091] In Scheme 3, the reaction is exemplary depicted for obtaining a compound of formula (I) wherein in X of formula
(II), R1, R2 and R3 represent a methyl group. It is understood that R1, R2 and R3 can be varied by applying a trihydro-
carbylgermanyltrifluoromethane-sulfonate other than Me3Ge-OSO2CF3.
[0092] All compounds of formula (I) comprise the group of formula (II)
, wherein M, R1, R2 and R3 are defined as above. Depending on the selection of M, the group of formula (II) represents
an acylsilane or acylgermane group. Upon exposure to UV-VIS-light, the bond between M and the acyl group may be
cleaved, whereby a silyl/germanyl and an acyl radical is formed as a polymerization initiating structure, but in competition
to the cleavage into to radicals, a carbene structure might be formed:
[0093] This competition between the formation of polymerization initiating radicals and carbene formation is described
for acylsilanes by El-Roz, M. et al. in Current Trends in Polymer Science, 2011, vol. 15, pages 1 to 13.
[0094] Besides, in case in compound of formula (I) wherein R has the same meaning as X or is a group of formula
(III), the C-C bond of the 1,2-diketone moiety (-C(=O)-C(=O)-) may be cleaved upon exposure to UV-VIS-light into two
acyl radicals. This cleavage is exemplary shown for compound of formula (I) wherein R is a group of formula (III) and Y
is an oxygen atom, that is for a glyoxylate (-O-C=O)-C(=O)-) compound:
[0095] Besides, in compound of formula (I), there is a third possibility for a radical cleavage in case R is a compound
of formula (III) wherein Y is an oxygen atom and R4 is a substituted or unsubstituted hydrocarbyl group. Namely, an
intra- or intermolecular hydrogen abstraction might occur, where a hydrogen radical is abstracted:
EP 3 359 118 B1
23
5
10
15
20
25
30
35
40
45
50
55
[0096] Both the cleavage of a glyoxylate group and the hydrogen abstraction mechanism is known for photoinitiators
which do not contain silicium or germanium, such as ethyl phenylglyoxylate (Irgacure® MBF).
[0097] For compounds of formula (I) wherein R has the same meaning as X or is a group of formula (III), the present
inventors carried out molecular modelling calculations from which it appears that a Si-C or Ge-C bond cleavage can be
ruled out, since the C-C bond of the - C(=O)-C(=O)- moiety is weaker than the Si-C or Ge-C bond.
[0098] The compounds of formula (I) represent photoinitiators. Specifically, they may act as Norrish type I photoinitiators
and thus may be used alone, or in combination with a coinitiator (b2).
[0099] The dental composition may further comprise a coinitiator (b2). The dental composition may comprise one or
more coinitiator(s) (b2). The coinitiator may be selected from electron donors in the form of an amine compound and
compounds having a Si-H or Ge-H bond, and photoinitiators other than compound of formula (I).
The coinitiator (b2) may be an electron donor. Preferred electron donors include, for example, amines, amides, ethers,
thioethers, ureas, thioureas, ferrocene, sulfinic acids and their salts, salts of ferrocyanide, ascorbic acid and its salts,
dithiocarbamic acid and its salts, salts of xanthates, salts of ethylene diamine tetraacetic acid and salts of tetraphenyl-
boronic acid. Particularly preferred donors contain an electron donor atom such as a nitrogen, oxygen, phosphorus, or
sulfur atom, and an abstractable hydrogen atom bonded to a carbon or silicon atom alpha to the electron donor atom.
[0100] Particularly preferred amine compounds are tertiary amines selected from the group consisting of trieth-
anolamine, 4-N,N-dimethylaminobenzonitrile, methyl N,N-dimethylaminobenzoate, ethyl N,N-dimethylaminobenzoate,
N,N-dimethylaminoethyl methacrylate and isoamyl 4-N,N-dimethylaminobenzoate, N,N-dimethylaniline, N,N-dimethyl-
toluidine, N,N-diethanoltoluidine, dimethylaminoanisole, 1 or 2-dimethylaminonaphthalene. In particular, the tertiary
amine is selected from the group consisting of triethanolamine, methyl 4-N,N-dimethylaminobenzoate, ethyl 4-N,N-
dimethylaminobenzoate, 4-N,N-dimethylaminoethyl methacrylate and isoamyl 4-N,N-dimethylaminobenzoate.
[0101] The coinitiator (b2) may be a compound having a Si-H or Ge-H bond. Preferably, compounds having a Si-H or
Ge-H bond are trihydrocarbylsilanes or trihydrocarbylgermanes in which the three hydrocarbylgroups have the same
meaning as defined for R1, R2 and R3. More preferably, the compound having a Si-H or Ge-H bond is triphenylsilicium
hydride (Ph3SiH) or triphenylgermanium hydride (Ph3GeH), most preferably triphenylgermanium hydride (Ph3GeH).
[0102] The coinitiator (b2) may be a photoinitiator other than compound of formula (I). Such a photoinitiator may for
example be added to improve the matching of the emission spectrum of dental LED with the absorption of the photo-
initiating system. For example, if compound of formula (I) does not or not sufficiently absorb light within the range of 450
to 500 nm, it is preferred to add a photoinitiator having a good absorbtion within this range.
[0103] For the coinitiator (b2) in the form of a photoinitiator other than compound of formula (I), isopropylthioxanthone
is excluded.
[0104] A coinitiator (b2) in the form of a photoinitiator other than compound of formula (I) may be in the form of a
Norrish type I or type II photoinitiator.
[0105] The Norrish type I photoinitiator may be selected from the group consisting of a triazine derivate, 2,4-6-trimeth-
ylbenzoyl-diphenylphosphine oxide (Irgacure® TPO), 2,4-6-trimethylbenzoyl-diphenylphosphinate (Irgacure® TPO-L,
TPO-L), bis(2,4-6-trimethylbenzoyl)-phenylphosphineoxide (Irgacure® BAPO-X). Preferably, the Norrish type I photoin-
itiator is a triazine derivative, preferably tris(trihaloalkyl)-triazine, more preferably tris(trihalomethyl)-triazine, even more
preferably tris(trichloromethyl)-triazine and in particular 2,4,6-tris(trichloromethyl)-1,3,5-triazine.
[0106] Typical Norrish type II photoinitiators are e.g a 1,2-diketone or a 1,3 diketone. Examples of suitable 1,2-diketones
are camphor quinone, benzil, 2,2’- 3 3’- and 4,4’-dihydroxylbenzil, 2,3-butanedione, 2,3-pentanedione, 2,3-hexanedione,
3,4-hexanedione, 2,3-heptanedione, 3,4-heptanedione, 2,3-octanedione, 4,5-octanedionefuril, biacetyl, 1,2-cyclohex-
anedione, 1,2-naphthaquinone, and acenaphthaquinone. Examples of suitable 1,3-diketones are dibenzoyl methane,
benzoyl acetone and acetyl propionyl methane.
[0107] Preferably, the coinitiator (b2) is a Norrish type II photoinitiator, more preferably a 1,2-diketone, most preferably
camphor quinone.
EP 3 359 118 B1
24
5
10
15
20
25
30
35
40
45
50
55
[0108] It was surprisingly found that by means of adding a photoinitiator such as camphor quinone as a coinitiator
(b2), the matching of the absorption of polymerization initiator system comprising (b1) the compound of formula (I) with
the emission spectrum of an irradiation source can be improved compared to a conventional polymerization initiator
system based on a conventional Norrish type I or II photoinitiator.
[0109] It is preferred that the coinitiator is an electron donor in the form of an amine compound or a compound having
a Si-H or Ge-H bond, optionally in combination with a photoinitiator other than compound of formula (I).
[0110] The polymerization initiator system may further comprise one or more components selected from
(b3) an iodonium salt, a sulfonium salt and a phosphonium salt.
[0111] Preferably, the iodonium, sulfonium and phosphonium salts are selected from the following group:
(1) an iodonium compound of the following formula (VI):
R19-I+-R20 A-(VI)
wherein
R19 and R20 which are independent from each other, represent an organic moiety, and
A-is an anion;
(2) a sulfonium compound of the following formula (VII):
R21R22R23S+ A-(VII)
wherein
R21, R22 and R23 which are independent from each other, represent an organic moiety or wherein any two of
R21, R22 and R23 form a cyclic structure together with the sulfur atom to which they are bound,
and
A-is an anion;
(3) a phosphonium compound of the following formula (VIII):
R24R25R26P+ A-(VIII)
wherein
R24, R25 and R26 which are independent from each other, represent an organic moiety, and
A-is an anion;
[0112] In the iodonium compounds of formula (VI), R19 and R20 preferably represent an aromatic, an aliphatic or an
alicyclic group. An aromatic group may be a phenyl group. The phenyl group may be substituted by one or more straight
chain or branched alkyl groups having 1 to 6 carbon atoms, straight chain or branched alkoxy groups having 1 to 6
carbon atoms, aromatic groups such as aryl groups or aryloxy groups, alicyclic groups having 3 to 6 carbon atoms,
halogen atoms, hydroxyl groups, or amino groups. The aliphatic group may be a straight chain or branched alkyl groups
having 1 to 6 carbon atoms which may be substituted by one or more aromatic groups, alicyclic groups having 3 to 6
carbon atoms, halogen atoms, hydroxyl groups or amino groups. An alicyclic group may be a group having 3 to 6 carbon
atoms which may be substituted by one or more aromatic groups, aliphatic groups, halogen atoms, hydroxyl groups or
amino groups.
[0113] According to a preferred embodiment, the iodonium compound of formula (VI) is a diaryl iodonium salt. Examples
of useful diaryl iodonium salt include (4-methylphenyl)[4-(2-methylpropyl) phenyl] iodonium hexafluoroantimonate, in-
clude (4-methylphenyl)[4-(2-methylpropyl) phenyl] iodonium tetrafluoroborate, diphenyliodonium (DPI) tetrafluoroborate,
di(4-methylphenyl)iodonium (Me2-DPI) tetrafluoroborate, phenyl-4-methylphenyliodonium tetrafluoroborate, di(4-hep-
tylphenyl)iodonium tetrafluoroborate, di(3-nitrophenyl)iodonium hexafluorophosphate, di(4-chlorophenyl)iodonium hex-
afluorophosphate, di(naphthyl)iodonium tetrafluoroborate, di(4-trifluoromethylphenyl)iodonium tetrafluoroborate, DPI
hexafluorophosphate, Me2-DPI hexafluorophosphate; DPI hexafluoroarsenate, di(4-phenoxyphenyl)iodonium tetrafluor-
oborat, phenyl-2-thienyliodonium hexafluorophosphate, 3,5-dimethylpyrazolyl-4-phenyliodonium hexafluorophosphate,
DPI hexafluoroantimonate, 2,2’-DPI tetrafluoroborate, di(2,4-dichlorophenyl)iodonium hexafluorophosphate, di(4-
bromophenyl)iodonium hexafluorophosphate, di(4-methoxyphenyl)iodonium hexafluorophosphate, di(3-carboxyphe-
EP 3 359 118 B1
25
5
10
15
20
25
30
35
40
45
50
55
nyl)iodonium hexafluorophosphate, di(3-methoxycarbonylphenyl)iodonium hexafluorophosphate, di(3-methoxysulfonyl-
phenyl)iodonium hexafluorophosphate, di(4-acetamidophenyl)iodonium hexafluorophosphate, di(2-benzothienyl)iodo-
nium hexafluorophosphate, and DPI hexafluorophosphate.
[0114] Particularly preferred iodonium compounds of formula (VI) include diaryliodonium hexafluorophosphate such
as diphenyliodonium (DPI) hexafluorophosphate, di(4-methylphenyl)iodonium (Me2-DPI) hexafluorophosphate, diaryl-
iodonium hexafluoroantimonate, (4-methylphenyl)[4-(2-methylpropyl) phenyl] iodonium hexafluoroantimonate, (4-meth-
ylphenyl)[4-(2-methylpropyl)phenyl]iodonium hexafluorophosphate (Irgacure® 250, commercial product available from
BASF SE), (4-methylphenyl)[4-(2-methylpropyl) phenyl] iodonium tetrafluoroborate, 4-octyloxyphenyl phenyliodonium
hexafluoroantimonate, 4-(2-hydroxytetradecyloxyphenyl)phenyliodonium hexafluoroantimonate, and 4-(1-methyle-
thyl)phenyl 4-methylphenyliodonium tetrakis(pentafluorophenyl)borate.
[0115] According to a particularly preferred embodiment, the iodonium compounds of formula (VI) are selected from
the group consisting of DPI hexafluorophosphate and 4-methylphenyl)[4-(2-methylpropyl)phenyl]iodonium hexafluoro-
phosphate (Irgacure® 250, commercial product available from BASF SE).
[0116] According to a preferred embodiment, the polymerizable matrix contains the iodonium compound of the following
formula (VI), preferably in the form of a diphenyl iodonium (DPI) or di(4-methylphenyl)iodonium (Me2-DPI) compound,
more preferably di(4-methylphenyl)iodonium (Me2-DPI), in an amount from 0.001 to 2 percent by weight based on the
total weight of the composition.
[0117] A preferred sulfonium compound of the formula (VII) is S-(phenyl)thianthrenium hexafluorophosphate of the
following formula:
[0118] The phosphonium compound of formula (VIII) may be a tetrakis-(hydroxymethyl)-phosphonium (THP) salt or
a tetrakis-(hydroxymethyl)-phosphonium hydroxide (THPOH) salt, wherein the anion A-is selected from the group con-
sisting of formate, acetate, phosphate, sulphate, fluoride, chloride, bromide and iodide.
[0119] In a salt of a compound of any one of formula (VI) to (VIII), the anion may be an anion selected from halogenides
such as chloride, bromide and iodide, hexafluorophosphate, tetrafluoroborate, tetraphenylborate, hexafluoroantimonate
and trifluoromethylsulfonate.
[0120] The use of (b1) a compound of formula (I) and (b2) an optional coinitiator together with (b3) an optional iodonium-,
sulfonium or phosphonium salt may provide for a synergistic effect, in particular in the case of iodonium salts.
[0121] Preferably, the polymerisation initiator system (b) comprises a combination of components (b1), (b2) and (b3).
More preferably, the polymerisation initiator system (b) comprises:
(b1) a compound of formula (I),
(b2) a coinitiator being an amine compound or a compound having a Si-H or Ge-H bond, and optionally additionally
a coinitiator being an 1,2 diketone photoinitiator, and
(b3)a iodonium salt, a sulfonium salt or a phosphonium salt.
[0122] According to a particularly preferred embodiment, polymerisation initiator system (b) comprises
(b1) a compound of formula (I), preferably selected from the group consisting of benzoyldiphenylmethylsilane (BDM-
Si), benzoyltrimethylsilane (BTMSi) and tert-butyl (tert-butyldimethylsilyl)glyoxylate) (DKSi),
(b2) a coinitiator being ethyl N,N-dimethylaminobenzoate (EDB) or triphenylgermanium hydride (Ph3GeH), and
optionally additionally camphor quinone (CQ), and
(b3)a diphenyliodonium (DPI) salt, preferably DPI hexafluorophosphate.
[0123] It was surprisingly found that owing to synergistic effects between components (b1), (b2) and (b3), a higher
EP 3 359 118 B1
26
5
10
15
20
25
30
35
40
45
50
55
conversion rate of the compounds having a polymerizable double bond (a) and more advantageous kinetics in terms of
the polymerization time can be obtained compared with a polymerization initiator system consisting of (b1). Furthermore,
a polymerization initiator system comprising components (b1), (b2) and (b3) is particularly suitable for polymerizing
relatively thin films of up to 0.1 mm, such as adhesive films, as well as for relative thick samples having a thickness of
about 1 to 2 mm or more, such as fillings and prosthetics. Besides, a polymerization initiator system comprising com-
ponents (b1), (b2) and (b3) provides for good bleaching, that is, colorless polymers are obtained. When camphor quinone
(CQ) is used as additional coinitiator, for the polymerization initiator system comprising components (b1), (b2) and (b3),
the aforementioned effects are significantly improved compared to a conventional polymerization initiator system con-
sisting of camphor quinone (CQ) as polymerisation initiator in combination with components (b2) and (b3).
[0124] Preferably, the polymerization initiator system further comprises
(b4) an aromatic tertiary phosphine compound of the following formula (IV):
Z-R5(IV)
wherein
Z is a group of the following formula (V)
R6(Ar)P- (V)
wherein
R6 represents a substituted or unsubstituted hydrocarbyl group;
Ar represents a substituted or unsubstituted aryl or heteroaryl group;
R5is a substituted or unsubstituted hydrocarbyl group or a group LZ’, wherein
L is a substituted or unsubstituted divalent hydrocarbyl group which may contain a linkage selected from an ether
linkage, a thioether linkage, an ester linkage, an amide linkage, and a urethane linkage and
Z’ has the same meaning as Z, whereby Z and Z’ may be the same or different;
wherein the group R6 and Ar may be substituted by one or more groups selected from a hydroxyl group, an oxo group,
a -NR7R8 group (wherein R7 and R8, which may be the same or different, are selected from a hydrogen atom and
C1-6alkyl groups), a carboxyl group, and a group having a polymerizable double bond, and
R5 and L may be substituted by one or more groups selected from a hydroxyl group, an oxo group, a -NR7R8 group
(wherein R7 and R8, which may be the same or different, are selected from a hydrogen atom and C1-6 alkyl groups), a
carboxyl group, and a group having a polymerizable double bond.
[0125] In the aromatic tertiary phosphine compound of the formula (IV), moieties Z, R5, Ar, F6, L, Z, Z’ may be defined
as follows:
For R6, the monovalent hydrocarbyl group may be an alkyl group, a cycloalkyl group, a cycloalkylalkyl group, an arylalkyl
group or an aryl group.
[0126] Ar represents a substituted or unsubstituted aryl or heteroaryl group. An aryl group may be selected from a
phenyl group, a naphtyl group, a tolyl group, a xylyl group, and a styryl group. A heteroaryl group may be a pyridyl group.
[0127] L is a substituted or unsubstituted divalent hydrocarbyl group which may contain a linkage selected from an
ether linkage, a thioether linkage, an ester linkage, an amide linkage, and a urethane linkage. For L, the divalent hydro-
carbyl group may be an alkyldiyl group, a cycloalkyldiyl group, a cycloalkylalkyl-diyl group, an arylalkyl-diyl group or an
aryldiyl group. In a cycloalkylalkyl-diyl, one valency may be bonded to each of the cycloalkyl moiety or the alkyl moiety,
or both valencies may be bonded to either the cycloalkyl moiety or the alkyl moiety. In a arylalkyl-diyl group, each of the
aryl moiety or the alkyl moiety may be monovalent respectively, or either the aryl moiety or the alkyl moiety is divalent,
while the other moiety is nonvalent. In a cycloalkylalkyl-diyl, each of the cycloalkyl moiety or the alkyl moiety may be
monovalent respectively, or either the cycloalkyl moiety or the alkyl moiety is divalent, while the other moiety is nonvalent.
[0128] The following definitions apply both for the monovalent and the divalent hydrocarbyl group, therefore, for the
definition of the divalent hydrocarbyl group, the suffixes "diyl" and"-diyl" are bracketed.
[0129] An alkyl(diyl) group may be straight-chain or branched C1-20 alkyl(diyl) group, typically a C1-8 alkyl(diyl) group.
Examples for a C1-6 alkyl(diyl) group can include linear or branched alkyl(diyl) groups having 1 to 6 carbon atoms,
preferably 1 to 4 carbon atoms, for example, methyl(diyl), ethyl(diyl), n-propyl(diyl), isopropyl(diyl), n-butyl(diyl), iso-
butyl(diyl), sec-butyl(diyl), tert-butyl(diyl), n-pentyl(diyl), isopentyl(diyl) and n-hexyl(diyl).
[0130] A cycloalkyl(diyl) group may be a C3-20 cycloalkyl(diyl) group. Examples of the cycloalkyl(diyl) group can include
those having 3 to 14 carbon atoms, for example, cyclopropyl(diyl), cyclobutyl(diyl), cyclopentyl(diyl) and cyclohexyl(diyl).
EP 3 359 118 B1
27
5
10
15
20
25
30
35
40
45
50
55
A cycloalkylalkyl(diyl) group can include those having 4 to 20 carbon atoms.
[0131] A cycloalkylalkyl(-diyl) group can include a combination of a linear or branched alkyl(diyl) group having 1 to 6
carbon atoms and a cycloalkyl(diyl) group having 3 to 14 carbon atoms. Examples of the cycloalkylalkyl(-diyl) group can
for example, include methylcyclopropyl(-diyl) methylcyclobutyl(-diyl), methylcyclopentyl(-diyl), methylcyclohexyl(-diyl),
ethylcyclopropyl(-diyl), ethylcyclobutyl(-diyl), ethylcyclopentyl(-diyl), ethylcyclohexyl(-diyl), propylcyclopropyl(-diyl), pro-
pylcyclobutyl(-diyl), propylcyclopentyl(-diyl), propylcyclohexyl(-diyl).
[0132] An arylalkyl(-diyl) group may be a C7-20 arylalkyl(-diyl) group, typically a combination of a linear or branched
alkyl(diyl) group having 1 to 6 carbon atoms and an aryl(-diyl) group having 6 to 10 carbon atoms. Specific examples of
an arylalkyl(-diyl) group are a benzyl(-diyl) group or a phenylethyl(-diyl) group.
[0133] An aryl(diyl) group can include aryl(diyl) groups having 6 to 10 carbon atoms. Examples of the aryl(diyl) group
are phenyl(diyl) and naphtyl(diyl). Aryl(diyl) groups may contain 1 to 3 substituents. Examples of such substituents can
include halogen atoms, a cyano group, a hydroxy group, an amino group, C1-6 alkyl groups and C1-6 alkoxy groups.
Here, illustrative of the halogen atoms can be fluorine, chlorine, bromine and iodine. The C1-4 alkyl(diyl) groups are, for
example, methyl(diyl), ethyl(diyl), n-propyl(diyl), isopropyl(diyl) and n-butyl(diyl). Illustrative of the C1-4 alkoxy(diyl) groups
are, for example, methoxy(diyl), ethoxy(diyl) and propoxy(diyl). The alkyl(diyl) moieties in these substituents may be
linear, branched or cyclic.
[0134] Preferably, the hydrocarbyl group is an aryl(diyl) group selected from a phenyl(diyl) group and a naphthyl(diyl)
group, which groups may optionally be substituted by one to three groups selected from halogen atoms, a cyano group,
an amino group, a hydroxy group, C1-6 alkyl groups and C1-6 alkoxy groups, or wherein the hydrocarbyl group is a non-
aromatic hydrocarbyl group selected from a straight chain or branched alkyl group, a straight chain or branched alkenyl
group, or a straight chain or branched alkynyl group.
[0135] The C1-8 alkyl(diyl) group and the C3-14 cycloalkyl(diyl) group may optionally be substituted by one or more
members of the group selected from a C1-4 alkyl group, C1-4 alkoxy group, a phenyl group, and a hydroxy group. Examples
for a C1-4 alkyl group can include linear or branched alkyl groups having 1 to 4 carbon atoms, for example, methyl, ethyl,
n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl. Examples for an C1-4 alkoxy group can include linear or branched
alkoxy groups having 1 to 4 carbon atoms, for example, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy,
sec-butoxy, and tert-butoxy.
[0136] Moreover, in formula (IV), any of the hydrocarbyl group may be substituted by on or more groups selected from
halogen atoms, a cyano group, an amino group or a hydroxy group. Accordingly, in the hydrocarbyl groups some or all
hydrogen atoms are replaced by halogen atoms (e.g., fluoro, bromo, chloro), for example, halo-substituted alkyl groups
such as chloromethyl, chloropropyl, bromoethyl and trifluoropropyl, and cyanoethyl.
[0137] In case the hydrocarbyl group contains an alkyl(diyl) chain, one or more carbon atoms in the alkyl(diyl) chain
may be replaced by an oxygen atom, a sulfur atom, an amide group, an ester group, or a urethane group. In case the
hydrocarbyl group is an alkyl group having more than one carbon atom, the alkyl group contains an alkylene. Accordingly,
in case the hydrocarbyl group is an n-hexyl group, any of the carbon atoms of the alkylene chain excluding the terminal
methyl group may be replaced by an oxygen atom, a sulfur atom, an amide group, an ester group, a urethane group or
an NH group. Therefore, the following groups may be given as specific examples in case of one or more oxygen atoms:
[0138] In formula (IV), group R6 and/or Ar as well as R5 and/or may be substituted with a polymerizable double bond,
preferably a carbon-carbon double bond. Examples of polymerizable carbon-carbon double bonds include vinyl, conju-
EP 3 359 118 B1
28
5
10
15
20
25
30
35
40
45
50
55
gated vinyl, allyl, acryl, methacryl and styryl. Preferably, the polymerizable double bond is selected from the group
consisting of methacryl, acryl and styryl. More preferably, the double bond is styryl.
[0139] Preferably, R6 and Ar independently are aromatic hydrocarbyl groups selected from a phenyl group, a naphtyl
group, a tolyl group, a xylyl group, and a styryl group.
[0140] As regards R5, this moiety is preferably an aryl group, which may be substituted by one or more groups selected
from a hydroxyl group, an amino group, a -NR7R8 group (wherein R7 and R8, which may be the same or different, are
selected from C1-6 alkyl groups), a carboxyl group, and a group having a polymerizable double bond. Alternatively, R5
is preferably a group LZ’ wherein Z’ and Z are the same.
[0141] More preferably, R5 is a C1-6 alkyl group or a C1-6 alkenyl group, which groups may be substituted by one or
more groups selected from a hydroxyl group, an amino group, a - NR7R8 group (wherein R7 and R8, which may be the
same or different, are selected from C1-6 alkyl groups), a carboxyl group, and a group having a polymerizable double
bond. The group having a polymerizable double bond may be vinyl group, an allyl group, a (meth)acryloyloxy group or
a (meth) acryloylamido group.
[0142] Even more preferably, the aromatic phosphine compound is a compound of formula (IV) wherein Z is a group
of the following formula (V’):
[0143] Specific examples for a compound of formula (IV) include triphenyl phosphine (TPP), 4-(diphenylphosphino)sty-
rene (DPPS), 4-(diphenylphosphino)benzoic acid, 4-(diphenylphosphino) benzoic acid, 3-(diphenylphophonino)propi-
onic acid, (4-(diphenylphosphino) N,N’-dimethylaniline, 2,2’-bis(diphenylphosphino)benzophenone (BDPPEP),
bis[2-(diphenylphosphino)phenyl]ether (BDPPE), (4-Hydroxyphenyl)diphenylphosphine, allyldiphenylphosphine. Pref-
erably, the compound of formula (I) is triphenyl phosphine (TPP) or 4-(diphenylphosphino)styrene (DPPS), more pref-
erably 4-(diphenylphosphino)styrene (DPPS).
[0144] It was surprisingly found that aromatic tertiary phosphine compounds of formula (IV) may provide for both an
advantageous efficiency in terms of a higher polymerisation rate and a higher final conversion rate compared to a dental
composition comprising a polymerization initiator system without an aromatic tertiary phosphine compound of formula
(IV). Advantageously, the polymeriation rate may be adjusted within a range which still provides for corrections when
applying the dental composition to a patient’s tooth or when forming a prosthesis. Although photopolymerization is
achieved at a higher polymerisation and conversion rate, owing to the present polymerization initiator system, undesired
side reaction resulting e.g. in discoloration of the cured dental composition can be effectively suppressed. Besides, by
adding an aromatic tertiary phosphine compound of formula (IV) to the present polymerization initiator system, a yellow
coloration of the dental composition eventually formed already before light curing can efficiently be reduced/decreased.
That is, there is a photo-bleaching effect which provides for an advantageous effective reduction/decrease of yellow
discolorations of the dental composition, while the initiator system furthermore provides for an advantageous polymer-
ization and conversation rate throughout the whole course of time of the photopolymerization.
[0145] The present polymerisation initiator system is not only advantageous for relatively thin films of up to 0.1 mm
such as adhesive films, but also particularly suitable for polymerizing relative thick samples of a dental composition
having a thickness of about 1 to 2 mm or more, such as fillings and prosthetics.
[0146] Without wishing to be bound to theory, it is believed that a synergistic effect due to the combination of (b1) the
compound of formula (I) and (b2) the coinitiator together with (b3) the aromatic tertiary phosphine of formula (IV) is
provided according to the present invention.
[0147] A further positive effect associated with the application of tertiary phosphines of formula (IV) is that owing to
the tertiary phosphines of formula (IV), the present compositions may exhibit an advantageous storage stability, that is
the compositions keep the above characteristics of an advantageous efficiency in terms of a higher polymerisation rate
and a higher final conversion rate even after a long storage time, e.g. about 2 month.
[0148] From the above listed aromatic tertiary compounds of formula (IV), 4-(diphenylphosphino)styrene (DPPS) is
particularly preferred, since this compound provides for particularly improved photo-bleaching results compared to the
already advantageous results obtained with triphenyl phosphine (TPP). Besides, DPPS is particularly suitable for initiating
polymerization of thick samples of about 1 to 2 mm thickness. Besides, DPPS not only provides for an improved conversion
EP 3 359 118 B1
29
5
10
15
20
25
30
35
40
45
50
55
rate, but with DPPS, the conversion rate of the dental composition can be maintained even after a storage time of 2
weeks or more.
[0149] Preferably, in the present dental composition, the polymerization initiator system comprises component (b1),
(b2), (b3) and (b4) in a molar ratio ((b1) : (b2) : (b3) : (b4)) of 1 : (0.0 to 3.0) : (0.0 to 3.0) : (0.0 to 3.0), more preferably
1 : (0.1 to 2.0) : (0.1 to 2.0) : (0.1 to 2.0), even more preferably 1 : (0.2 to 1.0) : (0.2 to 1.0) : (0.2 to 1.0). It is preferred
that in the aforementioned molar ratio, the amount of the aromatic tertiary phosphine (b4) is 0.1 or higher. Because,
when the amount of the aromatic tertiary phosphine (b4) is less than 0.1 , then the conversion rate of the compounds
having a polymerizable double bond, and the reaction rate of the polymerization reaction (in the following termed "po-
lymerization rate") may be low. By means of the addition of the optional coinitiator (b2) and/or the optional (b3) iodonium
salt, sulfonium salt or phosphonium salt, both conversion rate and polymerization rate can be further advantageously
adjusted.
[0150] Optionally, the dental compositions of the present invention may further comprise a stabilizer, a solvent and/or
a particulate filler.
[0151] The dental composition may comprise one or more stabilizer(s).
[0152] The term "stabilizer" as used herein means any compound capable of preventing polymerizable compounds
contained in the dental composition from spontaneous polymerization during storage. However, the stabilizer does not
disturb or prevent intended polymerisation curing of the dental composition during application.
[0153] For example, the stabilizer may be a conventional stabilizer selected from the group consisting of hydroquinone,
hydroquinone monomethylether, tert-butyl-hydroquinone, tert-butylhydroxyanisol, propyl gallate and 2,6-di-tert-butyl-p-
cresol. From these conventional stabilizers, 2,6-di-tert-butyl-p-cresol is preferred.
[0154] Preferably, the stabilizer is a compound of the following formula (IX) and/or (X):
wherein
the R27, which may be the same or different, independently represent a branched C3-8 alkyl group or alkenyl or a
C3-8 cycloalkyl or cycloalkenyl group,
R28 represents a hydrogen atom, C1-6 alkyl or C2-6 alkenyl group, or a C1-6 fluoroalkyl or C2-6 fluoroalkenyl group,
X represents a group selected from a C1-8 alkyl group or a C3-8 cycloalkyl group, and
n is 0, 1 or 2.
[0155] It was surprisingly found that the class of stabilizers of formula (IX) and/or (X) provides for full or at least
substantial avoidance of discoloration upon storage and/or during photocuring. In particular, this class of stabilizers
provides for a surprising stabilizing effect in an acidic aqueous mixture so that a dental composition having a pH of less
than 7 may be provided which has no or substantially no discoloration upon storage and an excellent storage stability
due to an improved resistance against premature polymerization.
[0156] More preferably, the stabilizer is a compound of formula (IX) and/or (X) wherein the R27, which may be the
same or different, independently represent a branched C3-8 alkyl group or a C3-8 cycloalkyl group, and R28 represents
a hydrogen atom, C1-6 alkyl group or a C1-6 fluoroalkyl group, and n is 0 or 1. Even more preferably, the stabilizer is a
compound of formula (IX) and/or (X) wherein the R27, which may be the same or different, independently represent a
branched C3-8 alkyl group and R28 represents a hydrogen atom or a C1-6 alkyl group, and n is 0. Most preferably, the
stabilizer is a compound of the following formulae (IXa), (IXb) or (Xa):
EP 3 359 118 B1
30
5
10
15
20
25
30
35
40
45
50
55
wherein R’, R", R"’, R*, R** and R***, which may be the same or different, independently represent a methyl or an ethyl
group. It is particularly preferred that the stabilizer of formulae (IXa), (IXb) or (Xa) is a compound of the following formulae:
preferably DTBHQ.
[0157] The stabilizer DTBHQ is particularly preferred, since from experimental testings it appears that this stabilizer
provides the best results in view of the discoloration problematic, i.e. there is no or almost no discoloration of the dental
composition upon storage at 50°C for 30 days.
[0158] Discoloration upon storage and/or during photocuring may be determined according to ISO 7491:2000(en).
[0159] The dental composition according to the invention contains the stabilizer in an amount of 0.001 to 1 percent
by weight, preferably 0.005 to 0.8 percent by weight based on the total weight of the composition. When the amount of
the stabilizer is below the above indicated lower limit of 0.001, then storage stability of the dental composition might be
insufficient, since the amount of stabilizer is too small to provide a stabilizing effect. However, when the amount of
stabilizer is above the maximum threshold of 1 percent by weight, then the applicability of the dental composition might
be negatively affected, since higher amounts of stabilizer may disturb or even substantially prevent intended polymeri-
sation curing of the dental composition during application.
[0160] Suitable solvents may be selected from water, alcohols such as methanol, ethanol, propanol (n-, i-), butanol
(n-, iso-, tert.-), ketones such as acetone or the like.
[0161] The dental composition of the present invention may preferably comprise 5 to 75 percent by weight based on
the total weight of the composition of a solvent.
[0162] Suitable particulate fillers may be selected from fillers currently used in dental compositions. The filler should
be finely divided and preferably has a maximum particle diameter less than about 100 mm and an average particle
diameter less than about 10 mm. The filler may have a unimodal or polymodal (e.g., bimodal) particle size distribution.
[0163] The filler can be an inorganic material. It can also be a crosslinked organic material that is insoluble in the
polymerizable resin, and is optionally filled with inorganic filler. The filler can be radioopaque. Examples of suitable
particulate inorganic fillers are naturally-occurring or synthetic materials such as quartz, nitrides such as silicon nitride,
glasses derived from, for example Ce, Sb, Sn, Zr, Sr, Ba and Al, colloidal silica, feldspar, borosilicate glass, kaolin, talc,
titania, and zinc glass, and submicron silica particles such as pyrogenic silicas. Examples of suitable non-reactive organic
filler particles include filled or unfilled pulverized polycarbonates or polyepoxides. Preferably the surface of the filler
particles is treated with a coupling agent in order to enhance the bond between the filler and the matrix. The use of
suitable coupling agents include gamma-methacryloxypropyltrimethoxysilane, gamma-mercaptopropyltriethoxysilane,
gamma-aminopropyltrimethoxysilane, and the like.
[0164] The particulate filler may also be a filler obtainable by a process for the preparation of composite filler particles,
comprising:
(a) coating a particulate filler having a median particle size (D50) of from 1 to 1200 nm with a coating composition
containing a film-forming agent forming a coating layer on the surface of the particulate filler, said coating layer
displaying reactive groups on the surface of the coating layer, said reactive groups being selected from addition
polymerizable groups and step-growth polymerizable groups, thereby forming a coated particulate filler; subsequently
or concurrently
EP 3 359 118 B1
31
5
10
15
20
25
30
35
40
45
50
55
(b) agglomerating the coated particulate filler, optionally in the presence of a further crosslinking agent and optionally
in the presence of a further particulate filler not displaying reactive groups, for providing a granulation of the coated
particulate filler wherein the granulation contains the coated particulate filler particles and the optional further par-
ticulate filler particles separated from and connected to each other by at least one coating layer, whereby the at
least one coating layer may be crosslinked by crosslinking groups obtained by reacting the reactive groups and
optionally a further crosslinking agent;
(c) optionally milling, classifying and/or sieving the granulation of the coated particulate filler; and
(d) optionally further crosslinking the granulation of the coated particulate filler;
for providing composite filler particles having a median particle size (D50) of from 1 to 70 mm, wherein reactive
groups are transformed into crosslinking groups obtained by reacting reactive groups and optionally a further
crosslinking agent, and wherein the particulate filler is the main component by volume of the composite filler particles
as further described in EP-A 2 604 247.
[0165] The dental composition of the present invention may preferably comprise 0.1 to 85 percent by weight based
on the total weight of the composition of particulate filler.
[0166] The dental compositions of the present invention may further containpreservatives, pigments, free radical
scavengers, reactive and nonreactive diluents, coupling agents to enhance reactivity of fillers, rheology modifiers, and
surfactants.
[0167] Suitable preservatives may be selected from reducing agents such as vitamin C, inorganic sulfides and
polysulfides and the like.
[0168] According to a particularly preferred embodiment, the dental composition according to the invention comprises
(a) one or more compounds having at least one polymerizable double bond, preferably at least one of compounds
of formulae (A), (B), (C), (D), (E) and (F), more preferably at least one of the group consisting of bis-GMA, TGDMA,
UDMA, PENTA, BAABE and BADEP;
(b) a polymerization initiator system comprising
(b1) a compound of the following formula (I’):
X’-R’ (I’)
wherein
X’ is a group of the following formula (II’):
wherein
M is Si or Ge, preferably Si;
R1’ and R2’ are independently selected from the group consisting of a straight chain or branched C1-4
alkyl group, and a phenyl or benzoyl group optionally substituted with one substituent selected from
the group consisting of a halogen atom, a nitro group, a C1-4 alkoxy group and a -NRxRy group wherein
Rx and Ry independently from each other represent a C1-4 alkyl group, and
R3 is a straight chain or branched C1-4 alkyl group, or a phenyl group optionally substituted with one
substituent selected from the group consisting of a halogen atom, a nitro group, a C1-4 alkoxy group
and a -NRxRy group wherein Rx and Ry independently from each other represent a C1-4 alkyl group,
R’ (i) has the same meaning as X’, whereby the compound of formula (I’) may be symmetrical or un-
symmetrical; or
EP 3 359 118 B1
32
5
10
15
20
25
30
35
40
45
50
55
(ii) a group of the following formula (III’):
wherein
Y’ represents a single bond, an oxygen atom or a group NR", wherein R" has the same meaning
as R1’ and is selected independently therefrom;
R4’ has the same meaning as R3’ and is selected independently therefrom, or represents a trihy-
drocarbylsilyl group, a mono(hydrocarbylcarbonyl)dihydrocarbylsilyl group or a bi(hydrocarbyl-
carbonyl)monohydrocarbylsilyl)group, wherein the hydrocarbyl and hydrocarbylcarbonyl groups
have the same meaning as R1’, R2’ and R3’ and is selected independently therefrom, or
(iii) when M is Si, R may be a substituted or unsubstituted hydrocarbyl group having the same meaning
as defined for R3’ and being selected independently therefrom;
preferably the compound of formula (I) is selected from the group consisting of benzoyldiphenylmethylsilane
(BDMSi), benzoyltrimethylsilane (BTMSi), 4-chlorophenyl(trimethylsilyl)methanone, 3-chlorophenyl(trimethyls-
ilyl)-methanone, 4-nitrophenyl(trimethylsilyl)methanone, 3-nitrophenyl-(trimethylsilyl)methanone, tert-butyl
(tert-butyldimethylsilyl)glyoxylate) (DKSi), N,N-dimethylamino (tert-butyldimethylsilyl)glyoxamide and N,N-
dimethyl-amino (tert-butyldimethylgermanyl)glyoxamide, tert-butyl (trimethylgermanyl)glyoxylate (TKGe); most
preferably from the group consisting of benzoyldiphenylmethylsilane (BDMSi), benzoyltrimethylsilane (BTMSi),
tert-butyl (tert-butyldimethylsilyl)-glyoxylate) (DKSi) and tert-butyl (trimethylgermanyl)glyoxylate (TKGe);
(b2) optionally at least one coinitiator selected from the group consisting of an amine compound or a compound
having a Si-H or Ge-H bond, and optionally a photoinitiator other than compound of formula (I), preferably the
coinitiator is selected from the group consisting of triethanolamine, 4-N,N-dimethylaminobenzonitrile, methyl
N,N-dimethylaminobenzoate, ethyl N,N-dimethylaminobenzoate (EDB), N,N-dimethylaminoethyl methacrylate
and isoamyl 4-N,N-dimethylaminobenzoate, N,N-dimethylaniline, N,N-dimethyltoluidine, N,N-diethanoltoluid-
ine, dimethylaminoanisole, 1 or 2-dimethylaminonaphthalene, triphenylgermanium hydride, and camphor qui-
none (CQ); more preferably the coinitiator is at least one selected from the group consisting of EDB, Ph3GeH,
CQ and 2,4,6-tris(trichloromethyl)-1,3,5-triazine; most preferably, the coinitiator is EDB or Ph3GeH, optionally
in combination with CQ;
(b3) optionally a compound selected from the group consisting of (4-methylphenyl)[4-(2-methylpropyl) phenyl]
iodonium hexafluoroantimonate, include (4-methylphenyl)[4-(2-methylpropyl) phenyl] iodonium tetrafluorobo-
rate, diphenyliodonium (DPI) tetrafluoroborate, di(4-methylphenyl)iodonium (Me2-DPI) tetrafluoroborate, phe-
nyl-4-methylphenyliodonium tetrafluoroborate, di(4-heptylphenyl)iodonium tetrafluoroborate, di(3-nitrophe-
nyl)iodonium hexafluorophosphate, di(4-chlorophenyl)iodonium hexafluorophosphate, di(naphthyl)iodonium
tetrafluoroborate, di(4-trifluoromethylphenyl)iodonium tetrafluoroborate, DPI hexafluorophosphate, Me2-DPI
hexafluorophosphate; DPI hexafluoroarsenate, di(4-phenoxyphenyl)iodonium tetrafluoroborat, phenyl-2-
thienyliodonium hexafluorophosphate, 3,5-dimethylpyrazolyl-4-phenyliodonium hexafluorophosphate, DPI hex-
afluoroantimonate, 2,2’-DPI tetrafluoroborate, di(2,4-dichlorophenyl)iodonium hexafluorophosphate, di(4-
bromophenyl)iodonium hexafluorophosphate, di(4-methoxyphenyl)iodonium hexafluorophosphate, di(3-car-
boxyphenyl)iodonium hexafluorophosphate, di(3-methoxycarbonylphenyl)iodonium hexafluorophosphate, di(3-
methoxysulfonylphenyl)iodonium hexafluorophosphate, di(4-acetamidophenyl)iodonium hexafluorophosphate,
di(2-benzothienyl)iodonium hexafluorophosphate, DPI hexafluorophosphate, S-(phenyl)thianthrenium hex-
afluorophosphate, tetrakis-(hydroxymethyl)-phosphonium (THP) salt and tetrakis-(hydroxymethyl)-phosphoni-
um hydroxide (THPOH) salt; preferably, a diphenyliodonium (DPI) salt, most preferably DPI hexafluorophos-
phate;
(b4) optionally at least one aromatic tertiary phosphine selected from the group consisting of triphenyl phosphine
(TPP), 4-(diphenylphosphino)styrene (DPPS), 4-(diphenylphosphino)benzoic acid, 4-(diphenylphosphino) ben-
zoic acid, 3-(diphenylphophonino)propionic acid, (4-(diphenylphosphino) N,N’-dimethylaniline, 2,2’-bis(diphe-
nylphosphino)benzophenone (BDPPEP), bis[2-(diphenylphosphino)phenyl]ether (BDPPE), (4-hydroxyphe-
EP 3 359 118 B1
33
5
10
15
20
25
30
35
40
45
50
55
nyl)diphenylphosphine and allyldiphenylphosphine; preferably, the compound of formula (IV) is triphenyl phos-
phine (TPP) or 4-(diphenylphosphino)styrene (DPPS), most preferably 4-(diphenylphosphino)styrene (DPPS),
wherein the polymerization initiator system comprises component (b1), (b2), (b3) and (b4) in a molar ratio ((b1):
(b2) : (b3) : (b4)) of 1 : (0.0 to 3.0) : (0.0 to 3.0) : (0.0 to 3.0), preferably of 1 : (0.1 to 2.0) : (0.1 to 2.0) : (0.1 to 2.0).
In the above particularly preferred embodiment, the polymerization initiator system (b) preferably comprises com-
ponents (b2) or (b3), more preferably (b2) and (b3).
[0169] The compound of formula (I) according to the present invention may be used for the preparation of a dental
composition, preferably of a dental composition according to the invention as described above.
[0170] The invention will now be further illustrated by the following Examples.
Examples
Example 1: Preparation of acylsilanes
[0171] General procedure for the preparation of acylsilanes.[1] A 10 mL screw-capped glass tube with a magnetic
stir bar was charged with 0.054 g dichloro(η3-allyl)dipalladium(II) (0.3 mmol), 0.1 g Triethylphosphit (0.6 mmol) under
N2. Hexametyldisilane (0.96 g, 6.6 mmol) was added, and the mixture was stirred for 5 min at room temperature. After
that, 6 mmol benzoylchloride was added slowly to the yellow solution. The reaction mixture was heated at 110 °C for
2.5 h. After cooling to room temperature, the reaction mixture was purified by column chromatography using the indicated
eluent, without any preceding purification step. [1] Yamamoto, K.; Suzuki, S.; Tsuji, J. Tetrahedron Lett. 1980, 21, 1653.
Example 1a: Phenyl(trimethylsilyl)methanone
[0172] The title compound was prepared according to the general procedure using 0.84 g benzoylchloride (6 mmol),
0.054 g dichloro(η3-allyl)dipalladium(II) (0.3 mmol), 0.1 g Triethylphosphit (0.6 mmol) and 0.96 g hexametyldisilane (6.6
mmol). The crude product was purified by column chromatography and received as clear yellow oil.
1H-NMR [ppm]: (300 MHz, CDCI3) δ 7.85 - 7.82 (m, 2H, Pos. 4, 6), δ 7.57 - 7.44 (m, 4H, Pos. 1, 2, 3), δ 0.38 (s, 9H,
Pos. 10, 11, 12)
13C-NMR [ppm]: (75 MHz, CDCl3) δ 235.94 (Pos. 7); δ 141.48 (Pos. 5); δ 132.84 (Pos. 2); δ 128.80 (Pos. 4, 6); δ 127.63
(Pos. 1, 3); δ -1.21 (Pos. 10, 11, 12)
[0173] 5.000 g (9.7656 mmol) 2,2-bis[4-[2-hydroxy-3-methacryloyloxypropoxy)phenyl]propane (Bis-GMA), 1.1983 g
(4.1853 mmol) triethylene glycol dimethacrylate (TGDMA), 0.0497 g (0.2790 mmol) Benzoyl trimethylsilan (BTMS),
0.0999 g (0.6696) dimethylaniline and 0.0047 g (0.0212 mmol) 2,6-di-tert-butyl-p-cresol were mixed homogeneously.
The polymerization enthalpy of this mixture is ΔRH= -56.5 kJ/mol, measured with the DSC 7 (Perkin-Elmer).
Example 1b: 4-Chlorophenyl(trimethylsilyl)methanone
[0174] The title compound was prepared according to the general procedure using 1.05 g 4-Chlorobenzoyl chloride
(6 mmol), 0.054 g dichloro(η3-allyl)dipalladium(II) (0.3 mmol), 0.1 g Triethylphosphit (0.6 mmol) and 0.96 g Hexametyld-
isilan (6.6 mmol). The crude product was purified by column chromatography with ethyl acetate / n-Hexane (10:1) to
afford 0.215 g (17%) of the acylsilane as clear yellow oil.
EP 3 359 118 B1
34
5
10
15
20
25
30
35
40
45
50
55
Element. anal.: theor. (C: 56.46%, H: 6.16%) pract. (C: 57.71%, H: 5.82%)
1H-NMR [ppm]: (300 MHz, CDCl3) δ 7.78 - 7.75 (m, 2H, Pos. 4, 6), δ 7.46 - 7.44 (m, 2H, Pos. 1, 3), δ 0.37 (s, 9H, Pos.
10, 11, 12)
13C-NMR [ppm]: (75 MHz, CDCl3) δ 234.44 (Pos. 7); δ 139.65 (Pos. 2); δ 139.19 (Pos. 5); δ 129.15 (Pos. 4, 6); δ 129.97
(Pos. 1, 3); δ -1.28 (Pos. 10, 11, 12)
GC/MS: 212 [M+]
Example 1c: 3-Chlorophenyl(trimethylsilyl)methanone
[0175] The title compound was prepared according to the general procedure using 1.05 g 3-Chlorobenzoyl chloride
(3 mmol), 0.027 g dichloro(η3-allyl)dipalladium(II) (0.15 mmol), 0.05 g Triethylphosphit (0.3 mmol) and 0.48 g Hexam-
etyldisilan (3.3 mmol). The crude product was purified by column chromatography with ethyl acetate / n-Hexane (10:1)
to afford 0.220 (17%) of the acylsilane as clear yellow oil.
Element. anal.: theor. (C: 56.46%, H: 6.16%) pract. (C: 57.83%, H: 6.43%)
1H-NMR [ppm]: (300 MHz, CDCl3) δ 7.76 - 7.75 (m, 1H, Pos. 4), δ 7.73 - 7.69 (m, 1H, Pos. 2/6), δ 7.52 - 7.48 (m, 1H,
Pos. 2/6); δ 7.44 - 7.39 (m, 1H, Pos. 1); δ 0.38 (s, 9H, Pos. 10, 11, 12)
13C-NMR [ppm]: (75 MHz, CDCl3) δ 234.30 (Pos. 7); δ 142.63 (Pos. 2); δ 144.82 (Pos. 5); δ 128.27 (Pos. 4, 6); δ 124.27
(Pos. 1, 3); δ -1.17 (Pos. 10, 11, 12)
GC/MS: 212 [M+]
Example 1d: 4-Nitrophenyl(trimethylsilyl)methanone
[0176] The title compound was prepared according to the general procedure using 0.56 g 4-Nitrobenzoyl chloride (3
mmol), 0.027 g dichloro(η3-allyl)dipalladium(II) (0.15 mmol), 0.05 g Triethylphosphit (0.3 mmol) and 0.48 g Hexametyld-
isilan (3.3 mmol). The crude product was purified by column chromatography with ethyl acetate / n-Hexane (10:1) to
afford 0.13 g (19.5%) of the acylsilane as clear yellow oil.
Element. anal.: theor. (C: 53.79%, H: 5.87%, N: 6.27) pract. (C: 52.84%, H: 5.75%, N: 6.29)
1H-NMR [ppm]: (300 MHz, CDCl3) δ 8.35 - 8.32 (m, 2H, Pos. 1, 3), δ 7.95 - 7.92 (m, 2H, Pos. 1, 3), δ 0.40 (s, 9H, Pos.
10, 11, 12)
13C-NMR [ppm]: (75 MHz, CDCl3) δ 235.38 (Pos. 7); δ 149.98 (Pos. 2); δ 144.82 (Pos. 5); δ 128.27 (Pos. 4, 6); δ 124.27
(Pos. 1, 3); δ -1.17 (Pos. 10, 11, 12)
GC/MS: 223 [M+]
Example 1e: 3-Nitrophenyl(trimethylsilyl)methanone
[0177] The title compound was prepared according to the general procedure using 0.56 g 4-Nitrobenzoyl chloride (3
mmol), 0.027 g dichloro(η3-allyl)dipalladium(II) (0.15 mmol), 0.05 g Triethylphosphit (0.3 mmol) and 0.48 g Hexametyld-
isilan (3.3 mmol). The crude product was purified by column chromatography with ethyl acetate / n-Hexane (10:1) to
afford 0.3 g (22%) of the acylsilane as a yellow solid.
EP 3 359 118 B1
35
5
10
15
20
25
30
35
40
45
50
55
Element. anal.: theor. (C: 53.79%, H: 5.87%, N: 6.27) pract. (C: 52.73%, H: 5.77%, N: 6.31) 1H-NMR [ppm]: (300 MHz,
CDCl3) δ 8.87 - 8.85 (m, 1H, Pos. 2), δ 8.41 - 8.37 (m, 1H, Pos. 4), δ 8.14 - 8.12 (m, 1H, Pos. 6); δ 7.71 - 7.66 (m, 1H,
Pos. 1); δ 0.42 (s, 9H, Pos. 10, 11, 12)
13C-NMR [ppm]: (75 MHz, CDCI3) δ 233.83 (Pos. 7); δ 148.72 (Pos. 3); δ 142.11 (Pos. 5); δ 132.70 (Pos. 6); δ 130.10
(Pos. 1); δ 126.97 (Pos. 2), δ 122.60 (Pos. 4), δ -1.44 (Pos. 10, 11, 12)
GC/MS: 223 [M+]
Example 2: Preparation of germanylglyoxylates
[0178] General procedure for the preparation of germanylglyoxylates: Germanylglyoxylates can be synthesized
according to the general procedure depicted in Scheme 3.
[0179] Specifically, according to this general procedure, tert-butyl (trimethylgermanyl)glyoxylate (TKGe) having the
structural formula
was synthesized.
[0180] FTIR spectrum (BaF2 pellet) within wavelength range v = 1600 to 1780 nm (cf. Fig. 20): glyoxylate peak at
1720 cm-1.
[0181] Remarkably, this compound exhibits a good light absorption property in the 400-500 nm range with an extinction
coefficient of about 120 M-1cm-1 at 470 nm.
Examples 3 to 5: Photopolymerisation testing with different photoinitiator systems
Materials
[0182] Camphor quinone (CQ) was obtained from Aldrich and used as representative Norrish type II system (Scheme 7).
[0183] Ethyldimethylaminobenzoate (EDB) and triphenylgermanium hydride (Ph3GeH) used as coinitiators were ob-
tained from Aldrich. Benzoyltrimethylsilane (BTMSi) and benzoyldiphenylmethylsilane (BDMSi) (Scheme 7) were used
as Type I photoinitiators.
[0184] Diphenyliodonium hexafluorophosphate (DPI) was obtained from Aldrich. Bisphenol A-glycidyl methacrylate
(Bis-GMA) and triethyleneglycol dimethacrylate (TEGDMA) were obtained from Sigma-Aldrich and used with the highest
purity available (Scheme 7). A blend Bis-GMA/TEGDMA (70%/30% w/w) was used as benchmark matrix for dental
material photopolymerizations.
EP 3 359 118 B1
36
5
10
15
20
25
30
35
40
45
50
55
Irradiation Sources
[0185] Several light sources were used for the irradiation of the photocurable samples:
LED centered at 405 nm (M405L2 - ThorLabs; ∼110 mW cm-2), at 420 nm (M420L2 - ThorLabs; -80 mW cm-2), at 455
nm (M455L2 - ThorLabs; -60 mW cm-2) and blue dental LED centered at 477 nm (SmartLite® Focus from Dentsply -70
EP 3 359 118 B1
37
5
10
15
20
25
30
35
40
45
50
55
mW cm-2 in the selected conditions). Different emission spectra of the irradiation sources are given in Figure 1a and 1b.
Photopolymerization Experiments:
[0186] For the photopolymerization experiments, the conditions are given in the figure captions. The photo-sensitive
formulations were deposited on a BaF2 pellet in laminate (about 25 mm or 30 20 mm thick samples) or under air (about
20 mm thick for adhesives and 1.4 mm for thick samples) for irradiation with different lights. The evolution of the double
bond content of methacrylate was continuously followed by real time FTIR spectroscopy (JASCO FTIR 4100) at about
1630 cm-1 for thin samples (10-30 mm) or 6165 cm-1 for thick samples (1-2 mm - use of NIR), respectively.
Example 3: Photopolymerisation testing of polymerization initiator systems comprising an acylsilane
Testing of the light absorption properties of BDMSi and BTMSi:
[0187] Acylsilanes are usually characterized by a n-π* transition centered at about 420 nm. The absorption spectra of
BDMSi and BTMSi are depicted in Figures 2a and 2b. These two compounds allow good light absorption properties in
the 380-460 nm range and can be used for dental LED (alone or in combination with CQ).
Testing of photopolymerization with a three-component polymerization initiator systems
Example 3a: The acylsilane/EDB/DPI systems
[0188] Upon a LED at 405nm, the BDMSi/EDB/DPI was found as a good initiating system for a BisGMA/ TEGDMA
blend, as can be gathered from Figure 3. The best behavior was found for the three-component system BDMSi/EDB/DPI.
A similar behavior was found for BTMSi/EDB/DPI, as can be gathered from Figure 4. For all these experiments, a good
bleaching was observed and colorless polymers were obtained.
[0189] For thick samples (1.4 mm), a similar behavior was also found and the acylsilane/EDB/DPI can efficiently initiate
the polymerization of a representative dental resin (cf. Figure 5; for both BTMSi and BDMSi).
Example 3b: The acylsilane/Ph3GeH/DPI systems
[0190] Ph3GeH can also be used as coinitiator in the three-component acylsilane/Ph3GeH/DPI systems, as can be
gathered from Figure 6. The performance in presence of Ph3GeH was excellent and the bleaching was particularly
remarkable.
Example 3c: Four-component polymerization initiator systems
[0191] To improve the matching of the emission spectrum of dental LED with the absorption of the photo-initiating
system, the use of CQ/acylsilane combination can be worthwhile. In Figure 7, it can be noted that BDMSi will absorb
some light from the SmartLite® Focus in the 420-460 nm range. CQ/Ph3GeH/DPI and BDMSi/Ph3GeH/DPI were already
efficient systems; the CQ/BDMSi/Ph3GeH/DPI turned out to be better. The same behaviour was found for EDB as
coinitiator (CQ/BDMSi/EDB/DPI better than CQ/EDB/DPI). The final conversion reached for CQ/acysilane versus CQ
alone for different LEDs can be gathered from Table 1 below. It can be noted that a better performance was always
obtained for CQ/acylsilane versus CQ.
The CQ/acylsilane/EDB/DPI system:
[0192] As can be gathered from Figure 8, in the presence of the acylsilane BDMSi, the polymerization initiating ability
was improved, since a higher conversion rate was obtained for CQ/BDMSi/EDB/DPI (cf. curve (2)) compared with
CQ/EDB/DPI)(cf. curve (1).
The CQ/acylsilane/Ph3GeH/DPI system:
[0193] As can be gathered from Figure 9, in presence of the acylsilane BDMSi, the polymerization initiating ability was
improved, since a higher conversion rate was obtained for CQ/acylsilane/Ph3GeH/DPI (cf. curve (2)) compared with
CQ/Ph3GeH/DPI (cf. curve (1).
EP 3 359 118 B1
38
5
10
15
20
25
30
35
40
45
50
55
Example 4. Silylglyoxylate in polymerization initiator systems for dental materials.
Example 4: Photopolymerization testing of polymerization initiator systems comprising a glyoxylate silyl com-
pound
[0194] As an alternative for acylsilanes, silylglyoxylates may be used. As an example of the silylgyoxylate species,
tert-Butyl (tert-butyldimethylsilyl)glyoxylate (DKSi) was tested as compound of formula (I).
Testing of the light absorption properties of DKSi
[0195] As can be gathered from Figure 10, the absorption of DKSi was better than the absorption of the acylsilanes
BDMSi and BTMSi for the 450 to 500 nm range. Therefore, DKSi is more adapted for blue light irradiation than the
acylsilanes.
[0196] DKSi was found to be a good initiator for the polymerization of BisGMA/TEGDMA upon blue LED (SmartLite®
Focus) in laminate, i.e. when the formulation is covered with means for separating it from the air atmosphere, i.e. a
translucent foil (cf. Figure 11, curve (3)). DKSi can be used as a Type I initiator. In presence of EDB and DPI, the
polymerization profiles were improved, as can be gathered from Figure11, curve (1) or (2) versus curve (3). Therefore,
the two-component DKSi/EDB and the three-component DKSi/EDB/DPI systems are particularly attractive for applica-
tions in dental materials. From Figures 12 and 13 it can be seen that the polymerization process was also good under
air for thin samples (20 mm; Figure 12) as well as for thick samples (1.4 mm; Figure 13). However, as can gathered from
Figure 12 compared with Figure 11, for thin samples, conversion rate of DKSi alone dropped down, since with very thin
samples of e.g. 20 mm, there are very strong oxygen inhibition conditions, and thus, free radical polymerization will
always be inhibited under air with such a thin film due to the trapping of the free radicals. Furthermore, from Figure 12
it can be seen that in the presence of camphor quinone, the initiating ability of the CQ/DKSi/EDB/DPI system was only
moderately improved compared to DKSi/EDB/DPI (cf. curve 4 vs. curve 3) suggesting a good reactivity of DKSi versus
camphor quinone.
[0197] For the polymerization testing, the following mixtures were prepared:
The compositions according to Examples 4a, 4b and 4c have been prepared as described below, wherein the resulting
compositions of the starting materials were polymerized at 37°C. Then, the polymerization enthalpies of these compo-
sitions were measured with the differential scanning calorimeter DSC 7 from Perkin Elmer. The results of these meas-
urements are summarized in Table 2 below.
Example 4a:
[0198] 2.0000 g (4.2503 mmol) 11,14-Dioxa-2,9-diazaheptadec-16-enoicacid, 4,4,6,16 (or 4,6,6,16)-tetramethyl-
10,15-dioxo-,2-[(2-methyl-1-oxo-2-propen-1-yl)oxy]ethyl ester (UDMA), 0.0406 (0.1661 mmol) tert-Butyl (tert-butyld-
imethylsilyl) glyoxylate (DKSi) and 0.0017 g (0.0079 mmol) 2,6-di-tert-butyl-p-cresol were mixed homogeneously.
Example 4b:2.0000 g (4.2503 mmol) 11,14-Dioxa-2,9-diazaheptadec-16-enoicacid,
[0199] 4,4,6, 16 (or 4,6,6,16)-tetramethyl-10,15-dioxo-,2-[(2-methyl-1-oxo-2-propen-1-yl)oxy]ethyl ester (UDMA),
0.0415 (0.1698 mmol) tert-Butyl (tert-butyldimethylsilyl)glyoxylate (DKSi), 0.0288 g (0.1490 mmol) ethyldimethylami-
nobenzoate (EDB) and 0.0017 g (0.0079 mmol) 2,6-di-tert-butyl-p-cresol were mixed homogeneously.
Table 1. Conversions reached after 20s of irradiation for the polymerization of a blend Bis-GMA/TEGDMA (70%/30%
w/w); different LED irradiations (under air).
Polymerization initiator system LED at 405
110mW/cm2
LED at 420
80mW/cm2
LED at 455
60mW/cm2
LED at 477
70mW/cm2
CQ/BDMSi/Ph3GeH/DPI (1%/
2%/2%/2% w/w)
38 34 35 33
CQ/Ph3GeH/DPI (1%/2%/2%
w/w)
32 28 29 23
EP 3 359 118 B1
39
5
10
15
20
25
30
35
40
45
50
55
Example 4c:
[0200] 2.0000 g (4.2503 mmol) 11,14-Dioxa-2,9-diazaheptadec-16-enoicacid, 4,4,6,16 (or 4,6,6,16)-tetramethyl-
10,15-dioxo-,2-[(2-methyl-1-oxo-2-propen-1-yl)oxy]ethyl ester (UDMA), 0.0425 (0.1739 mmol) tert-Butyl (tert-butyld-
imethylsilyl)glyoxylate (DKSi), 0.0295 g (0.1527 mmol) ethyldimethylaminobenzoate (EDB), 0.0333 g (0.0782 mmol)
diphenyliodonium hexafluoro phosphate (DPI) and 0.0017 g (0.0079 mmol) 2,6-di-tert-butyl-p-cresol were mixed homo-
geneously.
Example 4d: Polymerization of thick samples (thickness = 6mm)
[0201] As can be gathered from Example 4a above, DKSi alone was already a good polymerization initiator system,
albeit the performance can be improved by addition of e.g. EDB or EDB/DPI, as shown e.g. in Examples 4b and 4c.
With a sample thicker than that applied in 3a, performance could be further improved. Therefore, DKSi (2% w/w) was
tested for the polymerization of UDMA formulations under air for thick samples of 6 mm (compared to 1.4 mm in Example
4a). The use of DKSi alone is for example interesting for amine-free formulations. The photopolymerization kinetic has
been recorded by following the decrease of the methacrylate C=C band by near infra-red spectroscopy (at about 6160
cm-1). As shown in Figure 16, an excellent photopolymerization profile was obtained with a very high polymerization
rate and final conversion. This clearly shows the high performance of DKSi alone as polymerization initiator system.
Example 4e: Bleaching of DKSi/EDB versus CQ/EDB for the polymerization of thick samples (thickness = 6mm)
[0202] The excellent bleaching property of DKSi is very useful for the synthesis of colourless or substantially colourless
polymer upon blue LED irradiation. In this example, the final colour for the polymer obtained by photopolymerization of
UDMA (thickness = 6 mm) was compared for the two polymerization initiator systems CQ/EDB (0.5%/0.5% w/w) and
DKSi/EDB (0.5%/0.5% w/w). Remarkably, the DKSi based photoinitiating system lead to a colourless polymer, while
the CQ based system leads to a slight yellow colour (cf. Figure 17).
Example 4f: Polymerization of thick samples (1.4 mm) using CQ/DKSi combination
[0203] DKSi and camphorquinone (CQ) exhibit an excellent matching with the emission spectrum of the "SmartLite"
LED (cf. Figure 18). Therefore, DKSi and CQ were used in combination with EDB for the polymerization of thick samples
(cf. Figure 19). Remarkably, for a similar weight content (0.5% w/w), DKSi and CQ exhibited a similar photoinitiating
ability: The polymerization profiles for CQ/EDB and DKSi/EDB were similar, as can be seen from curves (1) and (2) of
Figure 19. However, the molecular weight of DKSi is higher than CQ, this means that DKSi exhibits a higher molar
efficiency than EDB.
Surprisingly, the combination of CQ/DKSi togher with EDB lead to a remarkable polymerization profile (cf. Figure 19,
curve (3)) which was significantly improved compared to CQ/EDB and DKSi/EDB: The final conversion was increased
to about 10-15 %.
Example 5: Photopolymerization testing of a polymerization initiator system comprising a glyoxylate germanyl
compound
[0204] Tert-butyl (trimethylgermanyl)glyoxylate (TKGe) was tested as (b1) a compound of formula (I) together with
4,4,6,16 (or 4,6,6,16)-tetramethyl-10,15-dioxo-,2-[(2-methyl-1-oxo-2-propen-1-yl)oxy]ethyl ester (UDMA) as polymeriz-
able compound (a).
[0205] Figure 21 shows that the germanylglyoxylate TKGe exhibits a good photoinitiating ability upon blue LED which
is comparable to silylglyoxylates.
Table 2:
Examples DKSi [mol-%] EDB [mol-%] DPI [mol-%] ΔRH [kJ/mol] thmax [mi n]
Example 4a 3.75 - - -34.4 6 1.6 1.404
Example 4b 3.71 3.26 - -48.8 6 5.4 0.625
Example 4c 3.73 3.27 1.68 -47.2 6 8.9 0.630
EP 3 359 118 B1
40
5
10
15
20
25
30
35
40
45
50
55
Example 6: Comparison of the bleaching properties of a silylglyoxylate such as DKSi versus a bisacylgermane
such as BBG in methacrylate resins
[0206] For example, in EP 1 905 415 A1, bisacylgermanes such as bis-(benzoyl) diethylgermane (BBG) are proposed
as excellent photoinitiator upon blue light for dental materials. However, for a photoinitiator for use in the dental field,
besides of the photoinitiating performance, the bleaching property is a further important parameter for the photoinitiator’s
overall performance. From the absorption spectra shown in Figs. 22 and 23, it can be seen that remarkably, the bleaching
of the photoinitiator, i.e. the decrease of the associated absorption peak, is much faster for DKSi (cf. Fig. 23) compared
with BBG (cf. Fig. 22). Furthermore, from Figure 24 it can be seen that the yellow index significantly decreases for DKSi,
while for bis-(benzoyl) diethylgermane (BBG), there was only a minimal decrease of the yellow index. In conclusion,
Example 6 shows that DKSi provides for excellent bleaching properties, in particular when compared with bisacylger-
manes.
Example 7: Molecular modelling of compounds of formula (I) having a 1,2-diketone moiety
[0207] Molecular modelling was carried out with reference software Gaussian 09. For molecular modelling, the density
functional theory (DFT) was used, which provides reliable data.
[0208] The following parameters were calculated:
a) The light absorption properties absorption wavelength (λmax) and oscillator strength (indication on the ε),
b) the triplet state energy level (ET), and
c) the bond dissociation energy (BDE) for:
c1) the cleavage process (C-C or Si-C or Ge-C)
c2) the hydrogen abstraction reaction (C-H).
[0209] The calculations were carried out for DKSi as reference indicated as molecule 1, novel molecules 2 to 8 depicted
in Figure 25 and known molecules 9 to 19.
[0210] The results of the calculations are summarized in Tables 3 and 4 below.
Table 3:
molecule λmax [nm] Oscillator strength
reference DKSi 1 467 0.002
novel molecules
2 462 0.003
3 475 0.002
4 474 0.002
5 436 0.004
6 432 0.005
7 567 0.001
8 570 0.001
EP 3 359 118 B1
41
5
10
15
20
25
30
35
40
45
50
55
[0211] From the above calculation results, the following conclusions can be drawn:
1) For all molecules 1 to 19, a cleavage from the triplet state can be ruled out, since the triplet state energy level is
lower than the bond dissociation energy (BDE) leading to an endothermic (defavorable) cleavage reaction;
2) the cleavage occurs from the singlet excited state (S1), in agreement with experimental results;
(continued)
molecule λmax [nm] Oscillator strength
known molecules
9 478 0.001
10 478 0.003
11 475 0.001
12 481 0.001
13 482 0.001
14 472 0.001
15 484 0.003
16 472 0.004
17 440 0.004
18 486 0.001
19 712 0.001
Table 4:
molecule ET [kcal/mol] BDE Si-C=O or Ge-C=O [k cal/mol] BDE O =C-R [kcal/mol]
reference DKSi 1 42.03 71.57 67.15
novel molecules
2 41.38 71.07 67.88
3 42.15 73.68 71.08
4 42.06 72.07 68.4
5 45.19 71.48 63.92
6 45.13 73.46 67.16
7 34.91 70.37 63.05
8 34.87 72.51 67.01
known molecules
9 42.4 72.88 68.32
10 42.35 71.27 68.47
11 42.52 73.59 70.07
12 41.44 73.62 70.31
13 41.28 73.45 70.1
14 42.16 72.07 67.51
15 41.44 71.93 69.98
16 42.48 69.75 67.43
17 42.66 67.69 66.91
18 41.46 70.34 66.52
19 26.26 65.5 56.03
EP 3 359 118 B1
42
5
10
15
20
25
30
35
40
45
50
55
3) the Si-C cleavage can be ruled out: the C-C bond is weaker, in agreement with experimental results; and
4) from the calculations, it appears that molecules 2, 4, 5, 6, 9, 10, 14, 16, 17 and 18 may have a cleavability which
appears to be comparable to or even better compared with reference molecule 1 (DKSi). Furthermore, these mol-
ecules show an aborption wavelength λmax within the range of 432 to 478 nm, that is they are suitable for the light
sources typically applied in dental applications. In particular, molecules 5 and 6 are preferable, since they are
characterized by a potentially better cleavage process compared to the reference molecule (1) DKSi. These mole-
cules have an advantageously low bond dissociation energy (BDE) for the O=C-R bond and a high triplet state
energy level (ET). Molecules 7 and 19 may be readily cleaved owing to their low bond dissociation energy (BDE)
for the O=C-R bond, but their absorption wavelength λmax is not within the range typically applied in dental appli-
cations, but in the green (molecule 7: λmax = 567 nm) and red part (molecule 19: λmax = 712 nm) of the spectrum.
[0212] In conclusion, the above experimental examples support that owing to the present polymerization initiator
system, both a high conversion rate of the compounds having a polymerizable double bond of the matrix material and
advantageous kinetics in terms of the polymerization time were obtained. For example, DKSi as compound of formula
(I) alone, without the optional components (b2) coinitiator and (b3) iodonium salt, provides a high polymerization rate
and high final conversions, as can be gathered from Examples 4a and 4d.
[0213] Furthermore, the experimental examples show that the present polymerization initiator system is suitable for
polymerizing relatively thin films of up to 0.1 mm, such as adhesive films, as well as for relative thick samples having a
thickness of about 1 to 2 mm or more, such as fillings and prosthetics. With the present polymerization initiator system,
good bleaching is observed and thus, colorless polymers are obtained.
[0214] From the above examples, it appears that the advantageous effects of polymerizing relatively thin films of up
to 0.1 mm and good bleaching are particularly attained due to synergistic effects between (b1) compound of formula (I),
(b2) an optional coinitiator and (b3) an optional iodonium salt of the present polymerisation initiator system.
Claims
1. A dental composition comprising
(a) one or more compounds having at least one polymerizable double bond;
(b) a polymerization initiator system comprising
(b1) a compound of the following formula (I):
X-R (I)
wherein
X is a group of the following formula (II):
wherein
M is Si or Ge;
R1 represents a substituted or unsubstituted hydrocarbyl or hydrocarbylcarbonyl group;
R2 represents a substituted or unsubstituted hydrocarbyl or hydrocarbylcarbonyl group;
R3 represents a substituted or unsubstituted hydrocarbyl group; and
R
(i) has the same meaning as X, whereby the compound of formula (I) may be symmetrical or unsym-
metrical; or
EP 3 359 118 B1
43
5
10
15
20
25
30
35
40
45
50
55
(ii) is a group of the following formula (III):
wherein
Y represents a single bond, an oxygen atom or a group NR’, wherein R’ represents a substituted
or unsubstituted hydrocarbyl group;
R4 represents a substituted or unsubstituted hydrocarbyl group, a trihydrocarbylsilyl group, a mo-
no(hydrocarbylcarbonyl)dihydrocarbylsilyl group or a di(hydrocarbylcarbonyl)monohydrocarbylsi-
lyl group; or
(iii) when M is Si, R may be a substituted or unsubstituted hydrocarbyl group.
2. The dental composition according to claim 1, which further comprises (b2) a coinitiator.
3. The dental composition according to claim 2, wherein the coinitiator is an electron donor.
4. The dental composition according to claim 3, wherein the electron donor is an amine compound or a compound
having a Si-H or Ge-H bond.
5. The dental composition according to any one of the preceding claims which further comprises one or more compo-
nents selected from
(b3) an iodonium salt, a sulfonium salt and a phosphonium salt.
6. The dental composition according to claim 5, wherein the iodonium salt is selected from diphenyliodonium hex-
afluorophosphate and (4-methylphenyl)[4-(2-methylpropyl)phenyl]iodonium hexafluorophosphate.
7. The dental composition according to any one of the preceding claims, which further comprises
(b4) an aromatic tertiary phosphine compound of the following formula (IV):
Z-R5(IV)
wherein
Z is a group of the following formula (V)
R6(Ar)P- (V)
wherein
R6 represents a substituted or unsubstituted hydrocarbyl group;
Ar represents a substituted or unsubstituted aryl or heteroaryl group;
R5 is a substituted or unsubstituted hydrocarbyl group or a group LZ’, wherein
L is a substituted or unsubstituted divalent hydrocarbyl group which may contain a linkage selected from an
ether linkage, a thioether linkage, an ester linkage, an amide linkage, and a urethane linkage and
Z’ has the same meaning as Z, whereby Z and Z’ may be the same or different;
wherein the group R6 and Ar may be substituted by one or more groups selected from a hydroxyl group, an oxo
group, a carboxyl group, a group having a polymerizable double bond, and a -NR7R8 group wherein R7 and R8,
which may be the same or different, are selected from a hydrogen atom and C1-6 alkyl groups, and
R5 and L may be substituted by one or more groups selected from a hydroxyl group, an oxo group, a carboxyl group,
a group having a polymerizable double bond, and a -NR7R8 group wherein R7 and R8, which may be the same or
EP 3 359 118 B1
44
5
10
15
20
25
30
35
40
45
50
55
different, are selected from a hydrogen atom and C1-6 alkyl groups.
8. The dental composition according to any one of the preceding claims, wherein the polymerization initiator system
comprises component (b1), (b2), (b3) and (b4) in a molar ratio ((b1) : (b2) : (b3) : (b4)) of 1 : (0.0 to 3.0) : (0.0 to
3.0) : (0.0 to 3.0).
9. The dental composition according to any one of the preceding claims, which further comprises a solvent and/or a
particulate filler.
10. The dental composition according to any one of the preceding claims, wherein the dental composition is a dental
restorative or dental prosthetic composition.
11. The dental composition according to claim 10, which is selected from a dental adhesive composition, a dental
composite composition, a resin modified dental cement, a pit and fissure sealer, a desensitizer and a varnish.
12. Use of a compound of the following formula (I):
X-R (I)
wherein
X is a group of the following formula (II):
wherein
M is Si or Ge;
R1 represents a substituted or unsubstituted hydrocarbyl or hydrocarbylcarbonyl group;
R2 represents a substituted or unsubstituted hydrocarbyl or hydrocarbylcarbonyl group;
R3 represents a substituted or unsubstituted hydrocarbyl group; and
R
(i) has the same meaning as X, whereby the compound of formula (I) may be symmetrical or unsymmetrical;
or
(ii) is a group of the following formula (III):
wherein
Y represents a single bond, an oxygen atom or a group NR’, wherein R’ represents a substituted or
unsubstituted hydrocarbyl group;
R4 represents a substituted or unsubstituted hydrocarbyl group, a trihydrocarbylsilyl group, a mono(hy-
drocarbylcarbonyl)dihydrocarbylsilyl group or a di(hydrocarbylcarbonyl)monohydrocarbylsilyl group; or
(iii) when M is Si, R may be a substituted or unsubstituted hydrocarbyl group,
EP 3 359 118 B1
45
5
10
15
20
25
30
35
40
45
50
55
for the preparation of a dental composition.
Patentansprüche
1. Dentale Zusammensetzung, umfassend
a) eine oder mehrere Verbindungen, die mindestens eine polymerisierbare Doppelbindung aufweist/aufweisen;
b) ein Polymerisationsinitiatorsystem, umfassend
(b1) eine Verbindung der folgenden Formel (I):
X-R (I)
wobei
X eine Gruppe der folgenden Formel (II) ist:
wobei
M Si oder Ge ist;
R1 eine substituierte oder unsubstituierte Hydrocarbyl- oder Hydrocarbylcarbonylgruppe darstellt;
R2 eine substituierte oder unsubstituierte Hydrocarbyl- oder Hydrocarbylcarbonylgruppe darstellt;
R3 eine substituierte oder unsubstituierte Hydrocarbylgruppe darstellt; und
R
(i) die gleiche Bedeutung wie X hat, wobei die Verbindung der Formel (I) symmetrisch oder unsymme-
trisch sein kann; oder
(ii) eine Gruppe der folgenden Formel (III) ist:
wobei
Y eine Einfachbindung, ein Sauerstoffatom oder eine Gruppe NR’ darstellt, wobei R’ eine substi-
tuierte oder unsubstituierte Hydrocarbylgruppe darstellt;
R4 eine substituierte oder unsubstituierte Hydrocarbylgruppe, eine Trihydrocarbylsilylgruppe, eine
Mono(hydrocarbylcarbonyl)dihydrocarbylsilylgruppe oder eine Di(hydrocarbylcarbonyl)monohyd-
rocarbylsilylgruppe darstellt; oder
(iii) wenn M Si ist, R eine substituierte oder unsubstituierte Hydrocarbylgruppe sein kann.
2. Dentale Zusammensetzung nach Anspruch 1, die ferner
EP 3 359 118 B1
46
5
10
15
20
25
30
35
40
45
50
55
(b2) einen Koinitiator umfasst.
3. Dentale Zusammensetzung nach Anspruch 2, wobei der Koinitiator ein Elektronendonator ist.
4. Dentale Zusammensetzung nach Anspruch 3, wobei der Elektronendonator eine Aminverbindung oder eine Ver-
bindung ist, die eine Si-H- oder Ge-H-Bindung aufweist.
5. Dentale Zusammensetzung nach einem der vorhergehenden Ansprüche, die ferner eine oder mehrere Komponenten
umfasst, die ausgewählt sind aus
(b3) einem lodoniumsalz, einem Sulfoniumsalz und einem Phosphoniumsalz.
6. Dentale Zusammensetzung nach Anspruch 5, wobei das lodoniumsalz ausgewählt ist aus Diphenyliodoniumhexa-
fluorphosphat und (4-Methylphenyl)[4-(2-methylpropyl)phenyl]iodoniumhexafluorphosphat.
7. Dentale Zusammensetzung nach einem der vorhergehenden Ansprüche, die ferner Folgendes umfasst
(b4) eine aromatische tertiäre Phosphinverbindung der folgenden Formel (IV):
Z-R5(IV)
wobei
Z eine Gruppe der folgenden Formel (V) ist
R6(Ar)P- (V)
wobei
R6 eine substituierte oder unsubstituierte Hydrocarbylgruppe darstellt; Ar eine substituierte oder unsubstituierte
Aryl- oder Heteroarylgruppe darstellt;
R5 eine substituierte oder unsubstituierte Hydrocarbylgruppe oder eine Gruppe LZ’ ist, wobei
L eine substituierte oder unsubstituierte zweiwertige Hydrocarbylgruppe ist, die eine Bindung enthalten
kann, die aus einer Etherbindung, einer Thioetherbindung, einer Esterbindung, einer Amidbindung und
einer Urethanbindung ausgewählt ist, und
Z’ die gleiche Bedeutung wie Z hat, wobei Z und Z’ gleich oder verschieden sein können;
wobei die Gruppe R6 und Ar mit einer oder mehreren Gruppen substituiert sein können, die ausgewählt sind aus
einer Hydroxylgruppe, einer Oxogruppe, einer Carboxylgruppe, einer Gruppe, die eine polymerisierbare Doppel-
bindung aufweist, und einer -NR7R8-Gruppe, wobei R7 und R8, die gleich oder verschieden sein können, ausgewählt
sind aus einem Wasserstoffatom und C1-6-Alkylgruppen, und R5 und L mit einer oder mehreren Gruppen substituiert
sein können, die ausgewählt sind aus einer Hydroxylgruppe, einer Oxogruppe, einer Carboxylgruppe, einer Gruppe,
die eine polymerisierbare Doppelbindung aufweist, und einer -NR7R8-Gruppe, wobei R7 und R8, die gleich oder
verschieden sein können, ausgewählt sind aus einem Wasserstoffatom und C1-6-Alkylgruppen.
8. Dentale Zusammensetzung nach einem der vorhergehenden Ansprüche, wobei das Polymerisationsinitiatorsystem
die Komponenten (b1), (b2), (b3) und (b4) in einem Molverhältnis ((b1): (b2): (b3): (b4)) von 1: (0,0 bis 3,0): (0,0 bis
3,0): (0,0 bis 3,0) umfasst.
9. Dentale Zusammensetzung nach einem der vorhergehenden Ansprüche, die ferner ein Lösungsmittel und/oder
einen partikelförmigen Füllstoff umfasst.
10. Dentale Zusammensetzung nach einem der vorhergehenden Ansprüche, wobei die dentale Zusammensetzung
eine Zahnrestaurations- oder Zahnersatzzusammensetzung ist.
11. Dentale Zusammensetzung nach Anspruch 10, die ausgewählt ist aus einer Dentinadhäsivzusammensetzung, einer
Dentalkompositzusammensetzung, einem harzmodifizierten Dentalzement, einem Versiegelungsmittel für Vertie-
fungen und Risse, einem Desensibilisator und einem Lack.
12. Verwendung einer Verbindung der folgenden Formel (I):
EP 3 359 118 B1
47
5
10
15
20
25
30
35
40
45
50
55
X-R (I)
wobei
X eine Gruppe der folgenden Formel (II) ist:
wobei
M Si oder Ge ist;
R1 eine substituierte oder unsubstituierte Hydrocarbyl- oder Hydrocarbylcarbonylgruppe darstellt;
R2 eine substituierte oder unsubstituierte Hydrocarbyl- oder Hydrocarbylcarbonylgruppe darstellt;
R3 eine substituierte oder unsubstituierte Hydrocarbylgruppe darstellt; und
R
(i) die gleiche Bedeutung wie X hat, wobei die Verbindung der Formel (I) symmetrisch oder unsymmetrisch
sein kann; oder
(ii) eine Gruppe der folgenden Formel (III) ist:
wobei
Y eine Einfachbindung, ein Sauerstoffatom oder eine Gruppe NR’ darstellt, wobei R’ eine substituierte
oder unsubstituierte Hydrocarbylgruppe darstellt;
R4 eine substituierte oder unsubstituierte Hydrocarbylgruppe, eine Trihydrocarbylsilylgruppe, eine Mo-
no(hydrocarbylcarbonyl)dihydrocarbylsilylgruppe oder eine Di(hydrocarbylcarbonyl)monohydrocarbyl-
silylgruppe darstellt; oder
(iii) wenn M Si ist, R eine substituierte oder unsubstituierte Hydrocarbylgruppe sein kann,
zur Herstellung einer dentalen Zusammensetzung.
Revendications
1. Composition dentaire comprenant
a) un ou plusieurs composés ayant au moins une double liaison polymérisable ;
b) un système initiateur de polymérisation comprenant
(b1) un composé de formule générale (I) :
X-R (I)
EP 3 359 118 B1
48
5
10
15
20
25
30
35
40
45
50
55
dans laquelle
X représente un groupement de la formule (II) suivante :
dans laquelle
M représente Si ou Ge ;
R1 représente un groupement hydrocarbyle ou hydrocarbylcarbonyle substitué ou non substitué ;
R2 représente un groupement hydrocarbyle ou hydrocarbylcarbonyle substitué ou non substitué ;
R3 représente un groupement hydrocarbyle substitué ou non substitué ; et
R
(i) a la même valeur que X, de sorte que le composé de formule (I) peut être symétrique ou asymétrique ;
ou
(ii) représente un groupement de la formule (III) suivante :
dans laquelle
Y représente une liaison simple, un atome d’oxygène ou un groupement NR’, dans lequel R’
représente un groupement hydrocarbyle substitué ou non substitué ;
R4 représente un groupement hydrocarbyle substitué ou non substitué, un groupement trihydro-
carbylsilyle, un groupement mono(hydrocarbylcarbonyl)dihydrocarbylsilyle ou un groupement
di(hydrocarbylcarbonyl)monohydrocarbylsilyle ; ou
(iii) lorsque M représente Si, R peut représenter un groupement hydrocarbyle substitué ou non substitué.
2. Composition dentaire selon la revendication 1, qui comprend en outre (b2) un co-initiateur.
3. Composition dentaire selon la revendication 2, dans laquelle le co-initiateur est un donneur d’électrons.
4. Composition dentaire selon la revendication 3, dans laquelle le donneur d’électrons est un composé amine ou un
composé ayant une liaison Si-H ou Ge-H.
5. Composition dentaire selon l’une quelconque des revendications précédentes qui comprend en outre un ou plusieurs
composants choisis parmi
(b3) un sel d’iodonium, un sel de sulfonium et un sel de phosphonium.
6. Composition dentaire selon la revendication 5, dans laquelle le sel d’iodonium est choisi parmi l’hexafluorophosphate
de diphényliodonium et l’hexafluorophosphate de (4-méthylphényl)[4-(2-méthylpropyl)phényl]iodonium.
EP 3 359 118 B1
49
5
10
15
20
25
30
35
40
45
50
55
7. Composition dentaire selon l’une quelconque des revendications précédentes, qui comprend en outre
(b4) un composé phosphine tertiaire aromatique de formule (IV) suivante :
Z-R5(IV)
dans laquelle
Z représente un groupement de la formule (V) suivante
R6(Ar)P- (V)
dans laquelle
R6 représente un groupement hydrocarbyle substitué ou non substitué ;
Ar représente un groupement aryle ou hétéroaryle substitué ou non substitué ;
R5 représente un groupement hydrocarbyle substitué ou non substitué ou un groupement LZ’, dans lequel
L représente un groupement hydrocarbyle divalent substitué ou non substitué qui peut contenir une liaison
choisie parmi une liaison éther, une liaison thioéther, une liaison ester, une liaison amide, et une liaison
uréthane et
Z ’a la même signification que Z, de sorte que Z et Z’ peuvent être identiques ou différents ;
dans laquelle le groupement R6 et Ar peuvent être substitués par un ou plusieurs groupements choisis parmi un
groupement hydroxyle, un groupement oxo, un groupement carboxyle, un groupement ayant une double liaison
polymérisable, et un groupement -NR7R8 dans lequel R7 et R8, qui peuvent être identiques ou différents, sont choisis
parmi un atome d’hydrogène et les groupements alkyle en C1-6, et
R5 et L peuvent être substitués par un ou plusieurs groupements choisis parmi un groupement hydroxyle, un
groupement oxo, un groupement carboxyle, un groupement ayant une double liaison polymérisable et un groupement
-NR7R8 dans lequel R7et R8, qui peuvent être identiques ou différents, sont choisis parmi un atome d’hydrogène et
les groupements alkyle en C1-6.
8. Composition dentaire selon l’une quelconque des revendications précédentes, dans laquelle le système initiateur
de polymérisation comprend les composants (b1), (b2), (b3) et (b4) dans un rapport molaire ((b1) : (b2) : (b3) : (b4))
de 1 : (0,0 à 3,0) : (0,0 à 3,0) : (0,0 à 3,0).
9. Composition dentaire selon l’une quelconque des revendications précédentes, qui comprend en outre un solvant
et/ou une charge particulaire.
10. Composition dentaire selon l’une quelconque des revendications précédentes, dans laquelle la composition dentaire
est une composition de restauration dentaire ou prothétique dentaire.
11. Composition dentaire selon la revendication 10, qui est choisie parmi une composition adhésive dentaire, une
composition composite dentaire, un ciment dentaire modifié à la résine, un scellant pour caries et fissures, un
désensibilisant et un vernis.
12. Utilisation d’un composé de la formule générale (I) :
X-R (I)
dans laquelle
X représente un groupement de la formule (II) suivante :
EP 3 359 118 B1
50
5
10
15
20
25
30
35
40
45
50
55
dans laquelle
M représente Si ou Ge ;
R1 représente un groupement hydrocarbyle ou hydrocarbylcarbonyle substitué ou non substitué ;
R2 représente un groupement hydrocarbyle ou hydrocarbylcarbonyle substitué ou non substitué ;
R3 représente un groupement hydrocarbyle substitué ou non substitué ; et
R
(i) a la même valeur que X, de sorte que le composé de formule (I) peut être symétrique ou asymétrique ; ou
(ii) représente un groupement de la formule (III) suivante :
dans laquelle
Y représente une liaison simple, un atome d’oxygène ou un groupement NR’, dans lequel R’ représente
un groupement hydrocarbyle substitué ou non substitué ;
R4 représente un groupement hydrocarbyle substitué ou non substitué, un groupement trihydrocarbyl-
silyle, un groupement mono(hydrocarbylcarbonyl)dihydrocarbylsilyle ou un groupement
di(hydrocarbylcarbonyl)monohydrocarbylsilyle ; ou
(iii) lorsque M représente Si, R peut représenter un groupement hydrocarbyle substitué ou non substitué,
pour la préparation d’une composition dentaire.
EP 3 359 118 B1
51
EP 3 359 118 B1
52
EP 3 359 118 B1
53
EP 3 359 118 B1
54
EP 3 359 118 B1
55
EP 3 359 118 B1
56
EP 3 359 118 B1
57
EP 3 359 118 B1
58
EP 3 359 118 B1
59
EP 3 359 118 B1
60
EP 3 359 118 B1
61
EP 3 359 118 B1
62
EP 3 359 118 B1
63
EP 3 359 118 B1
64
EP 3 359 118 B1
65
REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader’s convenience only. It does not form part of the European
patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be
excluded and the EPO disclaims all liability in this regard.
Patent documents cited in the description
•EP 0076102 A1 [0008]
•EP 1905415 A1 [0009] [0206]
•EP 2103297 A1 [0010]
•US 20150080490 A1 [0011]
•WO 2015144579 A1 [0012]
•EP 1548021 A [0045]
•EP 2604247 A [0164]
Non-patent literature cited in the description
• EI-ROZ M. et al. Current Trends in Polymer Science,
2011, vol. 15, 1-13 [0013]
• YAMAMOTO K. et al. J. Tetrahedron Lett., 1980, vol.
21, 1653-1656 [0086]
• NICEWICZ D.A. et al. Org. Synth., 2008, vol. 85,
278-286 [0088]
• NICEWICZ D.A. J. Am. Chem. Soc., 2005, vol. 127
(17), 6170-6171 [0089]
• BOYCE G.R. et al. J. Org. Chem., 2012, vol. 77 (10),
4503-4515 [0089]
• BOYCE G.R. et al. Org. Lett., 2012, vol. 14 (2),
652-655 [0089]
•CHEMICAL ABSTRACTS, 1171-49-9 [0089]
• S.P. MALLELA et al. J. Fluorine Chem., 1989, vol.
44 (2), 309-328 [0090]
• EL-ROZ, M. et al. Current Trends in Polymer Sci-
ence, 2011, vol. 15, 1-13 [0093]
• YAMAMOTO, K. ; SUZUKI, S. ; TSUJI, J. Tetrahe-
dron Lett., 1980, vol. 21, 1653 [0171]