This paper describes a case study showing the steps taken by Strines Textiles Ltd in its efforts to achieve increased energy efficiency in textile processing. Major cost savings, now assessed at £200,000 annually, have been achieved. The important role played by monitoring in providing incentive and the ability to chart progress toward targets is demonstrated. Some of the actions taken show that in the long term it may well be possible for dyeing/printing/finishing works to be operated without a boiler house.
Different size types present different problems for the textile processor. In this article, Alan Milner looks at the importance of pretreatment in the dyeing and printing of cotton and polyester/ cotton, and in particular which methods of size removal give the greatest success.
The relation between the constitution and colouring properties of 1,2-naphthoylenebenzimidazole derivatives has been studied. The dyes were applied from aqueous dispersion to cellulose acetate, nylon, polyester and acrylic fibres, and by a mass-coloration technique to nylon, polyester and polypropylene fibres. The effects of the position of substituents on the substantivity of the dyes for the different fibres, on the colour obtained and on its fastness properties were also studied. Some new 1,2-naphthoylenebenzimidazole derivatives were prepared.
Various monoazo dyes suitable for transfer printing have been prepared from N—2cyanoethyl—1, 2, 3, 4—tetrahydroquinoline and compared with the corresponding N—methyl (kairoline) derivatives. The presence of a β—cyanoethyl group brings about significant hypsochromic shifts of the first absorption band and leads to some improvement in light—fastness properties on polyester fibre.
In this study, 2-arylhydrazone-3-ketiminobutyronitriles were synthesised and reacted with hydrazine hydrate to afford 5-amino-4-arylazo-3-methyl-1H-pyrazoles. These compounds were then diazotised and coupled with malononitrile to give pyrazolylazomalononitriles. Thirteen novel pyrazolo[5,1-c][1,2,4]triazine dyes were synthesised by heating pyrazolylazomalononitriles in glacial acetic acid and characterised by elemental analysis and spectral methods. The effect of varying pH and solvent upon the absorption ability of the dyes substituted with electron-withdrawing and electron-donating groups at their o-, m- and p-position was examined in detail.
Condensation of 2-bromo-, 2-sulpho- or 2-phenoxy-1,4-dihydroxyanthraquinone with primary or secondary amines affords a series of 2-aminated derivatives. These compounds colour synthetic-polymer fibres, particularly polyester, in red hues of good build-up and fastness to light. Colour-structure relationships of the dyes are discussed within the general context of substituent effects in 1,2,4-tri-donor-substituted anthraquinones.
An exhaust application method for 4,6-(p-β-sulphatoethylsulphonyl)anilino-1,3,5-triazin-2(1H)-one to dried lyocell fibre has been developed. The procedure employs a temperature gradient technique with all of the salt and alkali present at the start. This method gives consistent wet abrasion resistance values with a standard deviation only marginally inferior to Tencel A100. Subsequent dyeing of lyocell fibres, in turn with two reactive dyes, gave build-up profiles indistinguishable from untreated fibre. The lyocell–agent bonding was stable to high temperature polyester dyeing conditions at pH 6, but unexpectedly showed some instability (as evidenced by a fall in wet abrasion resistance values) when subjected to base-catalysed reactive dyeing conditions.
A series of 1,4-bis(alkylamino)anthraquinone dyestuffs were applied for supercritical fluid dyeing of unmodified polypropylene fabric, which is known to be difficult to dye in a conventional aqueous system. A marked tendency was shown that the dyeability improved as the carbon number of alkyl substituents on the anthraquinone chromophore increased. By evaluating the build-up curves of the dyestuff, it was found that the carbon number of optimum alkyl chain length for 1,4-bis(alkylamino)anthraquinone was 8–12. From the relationship between the build-up curve and the colour fastness, it was concluded that the upper limit of dyeing depth for good colour fastness was 40 mmol/kg of fibre.
Synthesis of eight novel heteroarylazonaphthoquinone dyes has been carried out by diazotisation of a range of heterocyclic amines in nitrosyl sulphuric acid and coupling these on to 2-hydroxy-1,4-naphthoquinone. The dyes have been characterised by elemental analysis and spectroscopic methods. The effect on the visible absorption spectrum of the substituents present, and external influences such as solvents, pH and temperature, has been investigated in detail.
Calculation of the n-electron excitation energies of naphthoquinonoid dyes has been carried out by means of the Pariser—Parr—Pople (PPP) method using the variable, β,γ-approximation. A good linear correlation between the observed and calculated values for the first π-π* excitation was found for a new series of naphthoquinonoid dyes. The effect of substituents on the colour of different dyes was studied on the basis of these calculated results, i.e. HOMO—LUMO energy levels and π-electron-density changes accompanying the excitation. The intramolecular charge-transfer character of the π-π* transition was shown to be the same as occurs in some anthraquinonoid dyes.
The synthesis of a series of 2-thioethers of 1,4-dihydroxyanthraquinone by various preparative routes is described. The colour, dyeing and fastness properties on synthetic-polymer fibres of these dyes is discussed in terms of the nature of the substituent in the thiol group. 2-(2-aminophenylthio)-l, 4-dihydroxyanthraquinone, which gave the new heterocycle 6,13-dihydroxyanthra-[2,3-b]benzo[d] thiophen-7,12-dione on Pschorr intramoleadar cyclization, was observed to undergo cyclization, during both its synthesis and its application to polyester fibres, to the blue coloured 7-hydroxy-14H-mphtho[2,3-a] pheno-thiazine-8,13-dione.
The visible spectra of a series of 1,4-disubstituted aminoanthraquinone dyes dissolved in different solvents and polymer substrates have been measured. The position of the absorption maximum has been correlated with a weighted mean ionization potential of the substituent groups. Solvent shifts were found to be small but the dependence on polarity and hydrogen-bonding ability was shown to act in opposite directions.A detailed examination of the characteristic double-peak structure of the visible-absorption band has shown that the splitting is due to vibrational effects. The variation in the absorbance ratio of the two peaks with substituent and solvent has been explained in terms of the relative disposition of the ground- and excited-state potential- energy curves. The effect of concentration on the double-peak ratio has been re-examined and found to be negligible.
Condensation of 2-bromo-1,4-dihydroxyanthraquinone with alcohols and phenols affords the 2-ether derivatives, which colour synthetic-polymer fibres, particularly polyester, in yellow-orange hues of good build-up and light fastness. The influence of the 2-ether substituent on the colour of these 1,2,4-tri-donor-substituted anthraquinones is discussed, together with the relative influence of the electron acceptor 2-sulphone substituent.
The dyeing of polyester–cotton blends with new alkali-hydrolysable azo disperse dyes based on N-ester-1,8-naphthalimide was investigated. Polyester–cotton blend fabrics were dyed using both one- and two-bath methods. Dyes 3 and 4 offered lower colour yield on polyester using the one-bath method. For the rest of the dyes, employing either the one- or two-bath method resulted in a similar colour yield on polyester fabric. The results for fastness properties and colour yield of the dyeings showed that the dyes were suitable for dyeing polyester–cotton blends using the one-bath method. The kinetic study of hydrolysis of the dyes in alkali media obeyed the pseudo first-order reaction rate.
Wool of 64s quality, in the form of yarn and cloth, has been given boiling treatments of 3 hr. with 50 min. for raising to the boil to imitate prolonged commercial dyeing processes but without the addition of dye. The pH of the solutions has been controlled at selected pH values between 1.5 and 9 by the gradual addition of sulphuric acid or sodium carbonate during the boiling. The wool has subsequently been examined for modification by means of determinations of alkali solubility, soluble nitrogen, disulphido sulphur, total sulphur, breaking load air-dry and wetted with water, extension at break, abrasion resistance, and loss in weight. A smaller quantity of 56s Corriedale wool has been treated concurrently though subjected to fewer tests. The conclusions reached are- (1) the wools have suffered minimum modification when boiled at pH 3–3.5; (2) sodium sulphate, in concentrations up to 9.2 g./litre, has shown relatively little effect on the wool within the pH range 1.7–6.8, but above pH 6.8 the presence of sodium sulphate has caused alkali damage, which increases rapidly with increase of salt concentration and rise of pH; (3) a strong correlation has been found between disulphidê content and wet breaking load for treatments having pH values above 4; a similar correlation has been found to apply to abrasion resistance after about 20% of the original disulphide sulphur has been broken down; (4) alkali solubility and soluble nitrogen have shown a strong correlation with abrasion resistance and to a lesser extent with wet strength for treatments having pH values below 2.5. The practical implications are discussed.
Using a set of dyed wool fabrics, the oxidative-bleach fading observed in ISO 105;C09 tests carried out at 40, 50 and 60 °C have been compared with that after 20 domestic wash cycles. It has been shown that the C09 test carried out at 50 °C is suitable for predicting the fading encountered after repeated domestic laundering.
A new single wash test procedure, ISO 105-C08, has been developed using a reference detergent, perborate and TAED (a low-temperature bleach activator) in order to better reflect domestic practice. Following an international trial, the procedure has been shown to be fully acceptable for the purpose of inter-laboratory comparisons.
A new laboratory single-wash test procedure that describes four test conditions, ISO 105-C12, has been developed to assess the colour fastness of textiles under industrial laundry conditions. Following an international trial, the intra-laboratory repeatability and the inter-laboratory reproducibility of the test were found to be fully acceptable. The results obtained under two of the laboratory test conditions were compared with five washes in an industrial laundry under similar conditions and acceptable correlations were found.
An international ring test has been carried out to assess the repeatability and reproducibility of the ISO 105-C08 test, modified to employ a liquor to cloth ratio of 20;1 in place of the current specification of 50;1. The results, from ten laboratories located in six countries, indicate that no adverse consequences are to be expected from reducing the liquor ratio, with the statistical variability obtained being well within the norm for this type of wash fastness test. It is therefore recommended that the standard be modified to allow the test to be conducted at a range of liquor to cloth ratios. The work in this paper was initiated by the TCI/81 committee and is sponsored by the Society's Technical Coordination Committee.
Catalytic wet air oxidation of CI Basic Yellow 11 and ink-plant wastewater was studied in a batch reactor. A platinum catalyst, supported on multi-walled carbon nanotubes, was employed. Compared with the results in the wet air oxidation of CI Basic Yellow 11 and ink-plant wastewater, the platinum-supported catalyst showed high activity for total oxygen carbon and toxicity removal at temperatures between 120 and 180 °C and total pressures of 30–50 bars, and it has been demonstrated that the activity depended strongly on the presence of a catalyst. The catalyst characterisations show no significant difference before or after reaction.
In the present study, Fenton and sono-Fenton processes were applied to the oxidative decolorisation of synthetic textile wastewater including CI Reactive Orange 127 and polyvinyl alcohol. Process optimisation [pH, ferrous ion (Fe2+) and hydrogen peroxide (H2O2)], kinetic studies and their comparison were carried out for both of the processes. The sono-Fenton process was performed by indirect sonication in an ultrasonic water bath, which was operated at a fixed 35-kHz frequency and 80 W power. The optimum conditions were determined as [Fe2+] = 20 mg l−1, [H2O2] = 15 mg l−1 and pH = 3 for the Fenton process and [Fe2+] = 25 mg l−1, [H2O2] = 5 mg l−1 and pH = 3 for the sono-Fenton process. The colour removals were 89.9% and 91.8% by the Fenton and sono-Fenton processes, respectively. The highest decolorisation was achieved by the sono-Fenton process because of the production of some oxidising agents as a result of sonication. Consequently, ultrasonic irradiation in the sono-Fenton process slightly increased the colour removal to 91.8%, while decreasing the hydrogen peroxide dosage to one-third of that of the Fenton process.
A study of dyeing wool fabric at 130 degreesC with and without fibre protective agents is carried out. Dyeing at 130 degreesC causes greater strength losses than dyeing at 120 degreesC. Damage is assessed more accurately by employing the Elmendorf tear test than by measuring the wet burst strength. The use in the dyebath of either Irgasol HTW, Remazol Black B, Lanasol Yellow 4G, sodium hydrogen maleate or potassium bromate reduces fibre damage. Potassium bromate is shown to offer the best protection under the conditions evaluated, but the wool is discoloured.
An earlier paper reported that the reactive dyes (not the disperse dyes) were responsible for the inability to achieve heavy depths of shade, when dyeing polyester/cotton blends by a one-bath process at 130 °C and neutral pH using reactive dyes containing a 3-carboxypyridinium-s-triazinyl group. It was shown that the poor colour yield of the bis-3-carboxypyridinium-s-triazine reactive dyes was because of their low exhaustion level at 130 °C and pH of 7.0–7.5. We now report the synthesis and evaluation of some bis-3-carboxypyridinium-s-triazine reactive dye structures, possessing highly substantive chromophores, as a means of obtaining high colour yield, on 100% unmercerised cotton, under the specified dyeing conditions. The technical performance of these dyes under such conditions was compared with that of selected Novacron (Cibacron) LS and Procion H-E dyes, applied under their recommended (atmospheric) dyeing conditions.
A continuous cultivation apparatus was constructed in order to improve the existing biological treatments for waste dye–liquor. The cleaning effect by Pseudomonas pseudomallei 13NA, an azo–assimilating bacteria, was examined. Using p–aminoazobenzene as a typical component of waste dye–liquor, it was found that the bacteria effectively removed it by biological degradation. For example, 80% of 10 ppm p–aminoazobenzene was removed by a three–stage continuous treatment.
Biodegradability of dyes by Pseudomonas pseudomallei 13NA was examined by spectrophotometric and thin layer chromatographic methods. The results are summarized as follows:(i) Pseudomonas pseudomallei 13NA intact cells were responsible for the decolorization of p–aminoazobenzene, C. I. Acid Orange 7, C. I. Acid Orange 12, C. I. Acid Orange 20, C. I. Acid Red 88, C. I. Direct Red 28, C. I. Direct Yellow 4, C. I. Basic Violet 1, C. I. Basic Violet 3 and C. I. Basic Orange 21.(ii) The half–decolorization time of the azo dyes used in this experiment showed good correlation with their molecular weights.(iiii) The detection of the reaction products of p–aminoazobenzene and C. I. Basic Violet 3 was examined by spectrophotometric and thin layer chromatographic methods. The results indicate the possibility of biodegradation of these dyes by Pseudomonas pseudomallei 13NA.
The biodegradability of azo acid dyes by continuous cultivation of Pseudomonas cepacia 13NA, a bacterium able to assimilate azo dyes, was investigated as a means of improving the results of conventional biological treatments for the clarification of the waste dye liquor. It was found that all the acid dyes used were removed in high efficiencies compared with the conventional biological treatments. Multi-stage continuous cultivation in the poor nutrient conditions used proved to be particularly effective for acid dyes that otherwise would be difficult to degrade.
This retrospect of the development of the carpet printing industry, mainly in the UK, traces its origins from the birth of calico hand printing in the late 18th century to the first attempts to apply mechanised methods of producing patterned carpets during the 1840s. The author's involvement with the industry from its rebirth in the 1950s, through the heydays of the 1970s and to the present is then reviewed. Developments both in machinery and dye technology, not all of which enjoyed long-term commercial success, are described, including the latest introduction of digital printing systems.
Eighteen isomeric dyes, each based on phenylazo-H-acid and containing two reactive groups, namely a monochlorotriazine group and a sulphuric acid ester of ß-hydroxyethylsulphone, were applied to cotton fabric by an exhaustion process at 60d̀C. The following properties were studied: spectra, uptake curves of the dyes before and after adding sodium carbonate, affinity, diffusion rate, and rates of hydrolysis and of reaction with cellulose, as evidenced by fixation and colour yield. Some significant correlations were found, but some missing or poor correlations indicated that there are further parameters or relationships between parameters that remain to be elucidated.
Single-crystal and X-ray powder data have previously been reported for a sample of Cl Solvent Yellow 18 [4-(2′, 4′-dimethyl phenyl azo)-5-methyl-2-phenyl-3H-pyrazol-3-one]. However, two more polymorphs have been identified, both in commercial as-received samples. The single-crystal and X-ray powder data are reported for one and the X-ray powder data alone for the second of these. In the first case the powder pattern has been indexed from cell dimensions given by single-crystal measurements.
The older literature has been surveyed to assess if any attempts had been made to determine systematically and scientifically the light fastness properties of the natural dyes. In the period under review (up to the 1870's) only Dufay in the early 1730's seems to have carried out a vigorous series of comparitive tests including the measurement of the total actinic energy falling on the dyed patterns by a fading standard. Otherwise the light fastness properties are never tabulated and are only mentioned infrequently and not consistently in the descriptions of the dyes.
Fresh X-ray data are given for the β- and γ- forms of linear trans-quinacridone (C.I. Pigment Violet 19, C.I. 46500). These new data are better resolved than those reported previously. The new pattern of the γ-form is compared with the previously reported pattern of γ‘-form, and it is concluded that the latter pattern could be accounted for by better resolution of the former and the reports of the existence of the γ’-form should be treated with caution.
An introduction outlining the scope and limitations of this paper is followed by a brief explanation of the essential structural features of metal-complex dyes.The earliest metal-complex dyes were produced directly within the fibre material by reacting a metallisable dye with a chromium compound in situ. The first chromium complex dyes prepared in substance, were the chromium complexes containing sulpho-groups, synthesised by R Bohn of BASF, in 1912, the application of which was first made possible after the discovery by Ciba of a satisfactory dyeing process based on the use of a dyebath made strongly acid with sulphuric acid. These two classes of dye dominated the dyeing industry into the 1950s.At that time 1:2 metal-complex dyes without sulphonic acid groups but containing nonionic substituents as solubilising groups were introduced. These complexes were applicable from neutral to weakly acid dyebaths, which minimised the damage to the fibres. These dyeings were characterised by high fastness to light and wet treatments. Later, for commercial reasons, sulphonic acid groups were again introduced into the dye molecule to increase their hydrophilic properties. These dyes also have become well established as a result of the introduction of new dyeing methods and the development of dyeing auxiliaries designed to promote level dyeing.In addition to these types of metal-complex dyes, further metal-complex dyes selected from the extensive patent literature of the last 50 years because of their interesting structure are described.
This review article has 319 references and covers developments in the dyes themselves, reducing agents and vatting procedures, fundamental work and production-oriented work on their application to cellulosic fibres, dyeing fibre blends, printed cellulosic fibres and their blends, and the use of vat leuco ester dyes.