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Mechanism of Softening Effect of Fabric Softener

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The mechanism of softening effect for fabric softeners has been explained as lowering of friction between the fibers. This explanation, however, has not been verified. The trend date of B-value of KES-FB2 and the result of perfect drying cotton threads indicate that the increase of hardness of cotton threads after the process of wetting by water and drying is caused by the cross-linking by the bound water between the cotton fibers. Thus, the softening effect of fabric softeners can mainly be discussed as the prevention of the formation of this cross-linkage.
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Journal of Materials Science Research; Vol. 8, No. 1; 2019
ISSN 1927-0585 E-ISSN 1927-0593
Published by Canadian Center of Science and Education
35
Mechanism of Softening Effect of Fabric Softener.
Takako Igarashi1,2 & Koichi Nakamura2
1 Household research Laboratories, Kao Corporation, Japan
2 Material Science Research Laboratories, Kao Corporation, Japan
Correspondence: Takako Igarashi, Household research Laboratories, Kao Corporation, Japan. E-mail:
igarashi.takako@kao.com
Received: December 7, 2018 Accepted: December 27, 2018 Online Published: December 31, 2018
doi: 10.5539/jmsr.v8n1p35 URL: https://doi.org/10.5539/jmsr.v8n1p35
Abstract
The mechanism of softening effect for fabric softeners has been explained as lowering of friction between the
fibers. This explanation, however, has not been verified. The trend date of B-value of KES-FB2 and the result of
perfect drying cotton threads indicate that the increase of hardness of cotton threads after the process of wetting by
water and drying is caused by the cross-linking by the bound water between the cotton fibers. Thus, the softening
effect of fabric softeners can mainly be discussed as the prevention of the formation of this cross-linkage.
Keywords: fabric, cotton, softener, friction, hydrogen bonding, bound water, non-freezing type of water,
cross-linkage
1. Introduction
The utility of cationic surfactants as household softeners was discovered incidentally in the course of a research
on direct-dye water-resistant conditioning agents for cotton fibers in the 1930s (Evance, 1969). Household
softeners were first sold in the US in 1955 (Egan, 1978; Puchta,1984) and, in 1962, Kao Softer was introduced to
Japanese market as the first softener with the dual action of fabric softening and imparting anti-static properties
(Minegishi, 1977). This product subsequently became established as a laundry consumer product indispensable
and essential to our daily lives; it currently holds a domestic market share of approximately 100 billion JPY (Japan
Nichiyohin-Keshohin Shimbun,2013). If we look at the types of softeners used globally, they can be roughly
divided into liquid-type softeners and sheet-type softeners (used in dryers). However, the use of sheet-type
softeners is limited to Western countries where drum-type washer-dryers are widely used, whereas only
liquid-type softeners are used in Japan. The functionality of softeners as the appealing message to the consumers
has diversified in recent years, with the market overflowing with a large number of products, are focused on
fragrance, deodorizing, and/or antibacterial qualities. Nonetheless, the primary function - value for consumers -
originally provided by softeners is still the softening of clothes, which remains unchanged.
Clothing fibers harden and become stiff after repeated routine washing and natural drying, but adding a small
amount of softener during the laundry rinse cycle can easily result in the condition that makes the clothes feel soft
to the touch. A type of fiber for which this effect is markedly notable is cotton. A large number of varied clothing
materials with superior appearance, texture properties, and functionality are in circulation in the apparel industry
owing to the recent spread of synthetic fibers. However, cotton fiber still occupies approximately 40% of the
global fiber production, fulfilling its role as a material central to the clothing aspects of the lives of humans, as it
has done since prehistoric times.
Therefore, this study summarizes existing researches on the essence of softening, focusing on cotton fiber, to
determine how cotton is softened.
2. Background of Previous Research
The main bases of household softeners distributed on today’s market can be broadly divided into di-long-chain
alkyl-type cationic surfactants (Iwazawa, Umezawa, Sawada, & Tsuji, 2001) and silicon (Harberder & Bereck,
2002; Miyasaka, 2004; Egawa, 2008), but almost all belong to the former category. The softness derived from the
use of cationic surfactants has been generally explained in relation to inter-fiber friction. That is, as shown in
Figure 1, when softeners are used on fibers in water, the cationic vesicles made of softener molecules are adsorbed
via electrostatic interactions to the negatively charged surfaces of the fibers; monolayers on the fiber surface are
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thus formed during the drying process with the alkyl groups having low surface energy facing toward the air side,
thereby reducing the friction between adjacent fibers. This lowered inter-fiber friction has been understood as the
cause of softness (American Association of Textile Chemists and Colorists [AATCC], 1978; Okumura & Yokoi,
1995; Seno & Tsuji, 1995; Takeuchi, 1999; Katayama, 2003; Miyazaki, 2005; Mohammadi, 2006; Morita, 2007;
Shimazaki & Sasai, 2007; Abe & Horiuchi, 2011). The grounds for this explanation are described below.
Figure 1. Conventional Explanation of the “Mechanism of Softening Effect”
First, it is known that softener exists in water as a phospholipid-like multi-layer film structure called as “vesicle”,
and because softeners have a cationic charge, it is thought that they are adsorbed onto the negatively charged
surfaces of fibers through electrostatic interactions (Suzawa & Yuzawa, 1966; Egan, 1978). The reason for the
fiber surfaces having a negative charge is that the chemical structure of cotton fiber is composed of cellulose, part
of which changes to a structure containing a carboxyl group through oxidation reactions (Buecking, Loetsch, &
Taeuber, 1984). The reason for this electrostatic-interaction-driven adsorption is thought to be an analogy caused
by the surfactant itself behaving as a cationically-charged colloid in water.
However, there has been uncertainty associated with this mechanism, because the sequence of adsorption is
thermodynamically unfavorable: in the case of cationic vesicle, adsorption is followed by the formation of
multilayers between the fibers and water by the cationic surfactants, which are sparingly soluble in water, together
with subsequent formation of a mono-layers between the fibers and air when the clothe is dried. This process is
quite complex.
In response to this, Cruzen (1995) argued that the hydrophobic properties (hydrophobic bonds) derived from the
long-chain alkyl groups were the driving force of adsorption, given that a softener can be adsorbed not only onto
cotton, but also onto other artificial fabric surfaces which does not have any meaningful electric charge. As an
additional interesting information, Minegishi (1997) investigated the adsorption rate of softener into cotton fiber
over time and reported that the time taken to reach adsorption equilibrium was heavily dependent on mechanical
force. This information suggests that softener adsorption is strongly governed by fiber collision. Furthermore, in
terms of the adsorbed state of the softener into the fabric surface, Okumura (1983) reported that softener is
uniformly adsorbed, retaining its multilayer particle shape, whereas Nakamura (1997) reported that the vesicles
adsorbed into the fabric surface collapsed during the drying process, forming a circular shape with overlapping
bilayer membranes that then transitioned to an interdigitated structure with reduced thickness and finally becomes
the monolayer when this drying process ends with the alkyl-chains of the softening agent are exposed to air.
Sakai et al. (2019) recently used atomic force microscopy to observe the adsorption on the surface of mica, and
reported that the vesicles adsorbed by collision immediately expanded to form a double-layered molecular
membrane. The adsorption state of the softener molecules was then maintained without loss of the molecules from
the surface, because of the electrostatic interaction between the anionic part of the cotton surface and the cationic
moiety of the softener molecule. Based on these information, even now, there are still a number of theories on the
driving force behind the adsorption of softeners onto fibers and on the adsorption state, and we are not yet at a stage
where this phenomenon can be definitively explained.
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<Why fibers treated with softener become softer?>
As mentioned at the beginning of this article, the conventional or so-called “common theory” for the origin of this
softness has been explained with relation to the phenomenon of inter-fiber friction. There have been a large
number of reports since 1930 on attempts to capture the textile (texture) properties of fabric not only after
softening, but also when applying stress changes using external forces in order to establish some link with the
fiber’s properties. It can be said that softeners emerged on the market with this era as the backdrop. The report by
Evance (1969) is one of the review articles relating to softeners from this time and, in his report, he discussed that
plasticizing and friction reduction were the main causes of fiber softening. The most effective agent for
plasticizing cotton fibers is water, but the effectiveness of poly-alcohols and hygroscopic salt is also mentioned in
his review. However, when using a cationic surfactant, there is no plasticizing (intensity change) of the fiber itself
occurs (Brow & Linfield, 1957) and, considering that the agents used at that time did not thought to penetrate
inside the single fibers, lubrication on the fabric surface fastened upon was considered as the only cause of the
perceived softness. However, in this case, only proof-by-contradiction arguments have been made about this
concept, and there is no assertive basis indicating that the reduction of surface friction is the direct cause of the
fabric softening effect.
Specific attempts to link fiber friction properties with softness and to interpret the results have been carried out.
Larrat (1966) conducted a study using both a friction meter and Handle-o-Meter (a device used to evaluate the
bending stiffness of textiles, which measures composite values for bending and sliding and was developed by
Johnson & Johnson and manufactured and sold by Thwing-Albert) and reported that he observed a reduction in
friction with an increased perception of softness when using the friction meter, whereas he reported no correlation
was found when using the Handle-o-Meter. In contrast to this, Röder (1953) and Olofsson (1950) reported a
correlation between the perception of softness and reduced inter-fiber friction and a relative correlation between
the coefficient of static friction and the coefficient of dynamic friction, stating that having a small coefficient of
static friction was important for softness. In other words, these information indicated that the perception of
softness and the perception of squeaky feel are generated by differences in the “relative position” of static friction
and dynamic friction. Given that the studies of Roeder and Olofsson were cited by a large number of subsequent
softener-related reports, it can be assumed that these studies may have been the grounds for the establishment of
friction-reduction theory on softening agents. However, the coefficient of friction correlating to the extent of
softness does not always indicate a direct causal relationship. Motoyama & Saiuchi (1961) touched upon the report
made by Roeder and, although they affirmed the involvement of the friction phenomenon, they also pointed out
through measurement results that not only the absolute measurement values of the coefficient of friction changes,
but even the relative tendency can also change. Therefore, they mentioned that agents that effectively reduce
inter-fiber friction may not necessarily be effective for reducing the friction between skin and fiber, which is
essential when considering the texture of the softener-treated clothe. Furthermore, in an aforementioned report,
Crutzen (1995) also introduced the concept that good softeners do not necessarily effectively reduce the coefficient
of friction. The authors measured the friction of yarns using a combination of a number of different methods,
including using a μ-meter, but were unable to confirm a trend of consistent reduction in static friction and dynamic
friction when using softener.
Moreover, Sebastian, Bailey, Briscoe, and Tabor (1986) reported that the junction rupture force (JRF) value when
a single thread is pulled from a plain-woven fabric, namely the static coefficient of friction generated between the
fabric and the pulled thread, is a good indicator of softness. However, it was later clarified that this method not
only measures simple frictional force values, but also simultaneously measures the adhesive force between fibers.
Conversely, by looking at fiber properties other than friction, Valko (1966) investigated on using a drape meter,
which can be used to obtain an indicator of hardness, by measuring the extent to which fabric hang down from the
round tester table under its own weight, whereas Motoyama and Saiuchi (1961) proposed the Clark’s stiffness
testing method, which is able to measure bending and stiffness. Hawarth (1964) conducted experiments after
making a working hypothesis emphasizing the importance of fiber surface roughness and flexibility relating to
friction in order to explain the perception of softness, and, as a result, stated that its relationship with softness could
not be explained.
Within the flow of subsequent researches on texture of cloth, in 1972 the Textile Machinery Society of Japan
proposed the measuring gauge of texture and the Standardization Research Committee proposed Kawabata’s
evaluation system (KES, 1982) as the standard methods for measuring texture of cloth. This popularized the
quantification of cloth texture values, which was previously performed via subjective human evaluations. This
method can calculate basic texture values (KOSHI: stiffness, NUMERI: slimy-ness, FUKURAMI: fullness &
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softness, SHARI: crispness, HARI: anti-drape strength, KISHIMI: squeaky feel, SHINAYAKASA: flexibility,
SOFUTOSA: soft feel) from 17 mechanical properties concerning tensile properties, bending properties, shearing
properties, compression properties, surface properties, and thickness. Inoue, Sano, Uyama, and Niwa (1997) used
this method to investigate the effect of softeners and reported an improvement in the texture related properties
(NUMERI, FUKURAMI, SOFUTOSA, etc.) based on the increased shear properties, shear hysteresis, bending
stiffness, bending hysteresis, and tensile resilience, as well as changes in the surface properties. However, this
report does not present detailed reasons for the acquired results. The KES is widely and frequently used both in
Japan and overseas, but it is a method developed for measuring sheer fabric, such as those used in men’s suits.
Thus, it has been known from the outset that it cannot be used on various products, including products with piles
such as towels.
Subsequently, Laghlin (1991), Farooq and Schramm (2009), and others stated that the best method for
appropriately expressing soft feeling is to carry out sensory evaluations (subjective evaluations) by expert panelists,
which had been used since the beginning of this field of research, touching upon the viewpoint that indicates the
superiority of the human somatosensory sense. In this way, the softness of fabric is defined to be the sensations felt
by the person feeling the fiber with bare hands, which is recognized during manipulation of the fabric, such as
when performing compression and bending as one of the preference. Thus, at the current stage, we have not fully
reached to the point where we can fully discuss softness.
3. Mechanisms for the Production of New Softener Effects
To counter the aforementioned situation, we conducted research from a different perspective of that of
conventional methods in an attempt to understand the essential phenomenon that causes the feeling of stiffness at
first and then softness which is realized when softener is used (ref. Igarashi, Nakamura, Morita & Okamoto
2016). The details are described below.
Normally, various fiber processing agents are used in fiber manufacturing processes to improve operability during
machining processes and get the finishing effects. Therefore, to remove these fiber processing agents, if a fully
pre-laundered cotton towel is used and left to dry after being wet, the resulting towel would be very stiff, just as if
it had been starched. Generally, softeners are used to reduce this stiffness. On the other hand, when we replicated
routine washing operations, allowing the towel to dry naturally after removing all the water and shaking it. These
actions alone dramatically changed the stiffness of the towel, allowing for the arising of softness. The results
obtained after reproducing this phenomenon using a bundle of cotton thread washed in solvent are shown in Figure
2. When we compared the results of Treatment A (leaving the bundle to dry naturally after washing with water)
and Treatment B (leaving the bundle to dry naturally after shaking after removing the washing water), it is easy to
appreciate the significant differences in the appearance of both thread bundles. As mentioned earlier, the thread
bundle that underwent Treatment A was stiff, and thus it retained its horizontal shape without falling in the
direction of gravity, whereas the thread bundle that underwent Treatment B hung down completely.
Figure 2. Appearance of Cotton thread Bundles (without Softener)
Thus, we focused on this phenomenon in which cotton fibers dried naturally from a wet state become extremely
stiff, moving forward by searching for the mechanism that causes the appearance of the essential effects of
softeners by scrutinizing the factors that cause stiffness, which is the opposite of softness.
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Almost all of the secondary wall, which accounts for the majority of scoured cotton, is comprised of microfibrils of
regularly arranged cellulose molecules, and thus the presence of innumerable hydroxyl groups on the surface
(Rollons & Tripp, 1954) and simply removing water and shaking out a washed towel dynamically change the
softness of the fabric. Based on this finding, we thought that the aforementioned stiffness phenomenon was
derived from some kind of 3-dimensional bond network between single fibers. Therefore, we used a pure bending
tester (KES-FB2, Kato Tech) to quantitatively interpret these bonds. We pre-treated cotton threads washed in
solvent and treated the resulted threads with different softener concentrations, namely 0–0.3% o.w.f. (on the
weight of the fabric), where 0.1% o.w.f. is the standard concentration for fabric softeners. The resulting threads
(35 threads) were arranged so that they did not come into contact with each other and were fixed at both ends with
double-sided tapes as shown in Figure 3. The threads were soaked with water and then ventilation-dried for two
full days in the standard condition (25 °C, 60% RH). Then, the pure bending tests were performed. These tests are
carried out to measure the moment when the sample is bent to 270°, i.e., the B-value (gfcm2/cm). The results
obtained by repeating these tests are shown in Figure 4. As can be seen from these results, (1) the B-value is
significantly reduced by the initial bending operation; (2) the B-value then converges to an almost constant value;
(3) increasing the softener concentration reduces the B-value for both (1) and (2), but if excessive agent is used
(0.2–0.3% o.w.f.), the initial reduction in (1) is no longer seen and the value in (2) remains constant at a low value.
Figure 3. Sample preparation
Figure 4. Results of the bending test
We think that the underlying factors that reflect the magnitude of this B-value are cross-links generated between
single fibers within the threads or, more specifically, cross-links between single fibers due to hydrogen bonds
mediated by bound water, because the stiffness is lost when the thread is complete-dried (described later). The
significant changes observed in the B-value caused by the initial bending operation can be interpreted as a
phenomenon corresponding to the destruction of the cross-linked structure through the application of the physical
force for bending. To confirm this possible involvement of water molecules, we conducted the same investigation
using fibers without hydroxyl groups and with low standard moisture regain, such as polyester (Shimazaki,2009),
and found that the B-values of (1) and (2) consistently remained almost unchanged, irrespective of the softener
treatment conditions.
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Figure 5. Changes after the Treatment in vacuo
Figure 6. The image of two types of hydrogen bonding betweeen the fibers
Based on the above information, the latter recovered B-values observed for the cotton threads can be interpreted as
results that reflect the additional stiffness applied to the threads through the reforming of the hydrogen bonds
formed between single fibers. Incidentally, the reason for that there is almost no recovery in the stiffness reduction
associated with the initial bending operation of cotton threads is thought to be because the hydrogen bonds formed
during natural drying are formed in the presence of the meniscus force (Campbell, 1947) acting between fibers;
once those bonds collapse, as the distances between these single fibers are significantly big, and thus the bonds
cannot be restored.
Then, we attempted to determine whether these hydrogen bonds were caused by direct coupling between hydroxyl
groups on single fibers or actually caused by hydrogen bonds mediated by bound water (Kohata, Miyagawa,
Takaoka, & Kawai, 1986). We fixed one end of the samples shown in Figure 3 and confirmed that there was almost
no drooping at the other end of the threads, even when it was left at room temperature. We then attempted to adjust
the absolute drying conditions of the samples by placing them in a desiccator and heating them to 110 °C under a
reduced pressure. The results, as shown in Figure 5, showed significant drooping at the other end of the samples,
and the surface of the threads appeared to be fluffy. When these same samples were cooled down to room
temperature under drying conditions, a sensory evaluation was conducted immediately after, and the softness was
found to have significantly increased. These results suggest that the cause of the additional stiffness that occurs on
cotton after natural drying may not be mainly due to the direct coupling between hydroxyl groups on single fibers
(Figure 6, Ⅰ), but instead may be due to the three dimensional bonds among single fibers mediated by bound water
(cross-linking) (Figure 6, Ⅱ). This finding is considered to be a result that points to the importance of the cohesion
force between fibers, it was previously described by Sebastian (1986) as “adhesive force.”
If the mechanism behind the soft feeling associated with the use of softeners is considered based on the above
results, its main component would be inhibiting the formation of a hydrogen-bond network among single fibers
mediated by bound water.
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4. Conclusion
If we make an overview of the studies searching for the cause of the softness obtained through use of softeners, the
first notable point to be made is that a vast amount of research attempts has been made to interpret the texture based
on its relationship with the properties of fibers. The individual findings reported ar e all very interesting, but there is
a lack of findings that touch upon the fundamental principles for uniformly understanding these phenomena. From
this perspective, we hope that the research presented here may assist in the understanding of these principles.
In addition, as consumers continue to feel satisfied with the basic performance of a product, they will begin to
demand a higher-order different dimension of comfort amenities. Therefore, we, manufacturers and suppliers of
softeners need to ascertain and appropriately respond to these demands, as well as to uncover potential needs, to
proactively propose impactful products. With the recent development of remarkable analytical instruments, it has
become possible to accurately analyze the dissolution and adsorption state of softeners at the nano-level, as well as
to design softeners based on this information. As we move forward with these attempts, the role of the suppliers of
consumer goods is to skillfully integrate the latest information in the related fields of physical science, fiber
science, textile engineering, Kansei/Affective engineering, human engineering, and physiological sciences, which
are essential for deepening our understanding of texture, to build new fiber reforming technology that is able to
meet the need of the times, and to propose new products building on the results of these ventures.
Acknowledgments
We would like to express our sincere gratitude to Tetsuya Okano, Head of the Household Research Laboratory,
and Taku Mimura, Head of the Material Science Research Laboratory, Takeshi Kaharu, Manager of Material
Science Research Laboratory, Kao Corporation. I also appreciate to Kaoru Tsuji, former professor at Hokkaido
University who always gave me a good advice for this research.
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... They have the best resistance to heavy metal and alkaline earth salts when compared to anionic and cationic softeners. Although pseudoquaternary compounds do not act entirely like nonionic compounds, they do behave similarly and offer the best balance between softness and bath stability/compatibility. [24][25][26] The literature describes a wide variety of nonionic compositions for softening textile textiles. These nonionic textile softening formulations have a lot of benefits, but many of them also have a lot of drawbacks. ...
... To create products with 10-30% activity, many softener compositions are diluted with water, creating viscous liquids or pastes that are challenging to pour or pump and that are difficult to further dilute in cold water. [24] Many nonionic softeners are easily capable of adding softness to textile material treated with them, but they have the drawback of causing treated textile material to turn yellow over time or when exposed to high temperatures. While many textile compositions don't have the aforementioned drawbacks, they do have another drawback that prevents them from being used in the business, such as being too expensive. ...
... When applied to textile materials, the nonionic textile treatment compositions of this invention can be made into a fluid, pourable, easily handled dispersions of 10-30% dispersed solids. [24,27] Alkyl poly glucosides (APG) Alkyl poly glucosides are eco-friendly and natural surfactants produced from renewable resources (Persson, Kumpulainen, and Eriksson 2003). They have green chemical characteristics of low toxicity and good biodegradability as they break down into harmless products on degradation without persisting in the environment. ...
... The interaction between Glycerol and BC involved the formation of hydrogen bonds, which hindered the formation of extensive hydrogen bonding among adjacent cellulosic fibers, consequently reducing their interaction (Phan et al. 2023d;Muthu and Rathinamoorthy 2021a;Sun et al. 2018). This resulted in increased spacing between the fibers, reduced fiber-fiber contact, and facilitated relative movements between the fibers (Phan et al. 2023d;Muthu and Rathinamoorthy 2021a;Sun et al. 2018;Igarashi and Nakamura 2019;Igarashi et al. 2016;Igarashi and Nakamura 2017). Consequently, Glycerol acted as a friction-reducing agent between the fibers, similar to the mechanism of textile softeners (Phan et al. 2023d;Muthu and Rathinamoorthy 2021a;Sun et al. 2018;Igarashi and Nakamura 2019;Igarashi et al. 2016;Igarashi and Nakamura 2017). ...
... This resulted in increased spacing between the fibers, reduced fiber-fiber contact, and facilitated relative movements between the fibers (Phan et al. 2023d;Muthu and Rathinamoorthy 2021a;Sun et al. 2018;Igarashi and Nakamura 2019;Igarashi et al. 2016;Igarashi and Nakamura 2017). Consequently, Glycerol acted as a friction-reducing agent between the fibers, similar to the mechanism of textile softeners (Phan et al. 2023d;Muthu and Rathinamoorthy 2021a;Sun et al. 2018;Igarashi and Nakamura 2019;Igarashi et al. 2016;Igarashi and Nakamura 2017). Additionally, it was observed that Glycerol improved the wetting properties of SiO 2 , which contributed to the softness enhancement of BC-based IPN leatherette (Moldovan et al. 2014). ...
Article
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The negative consequences of fast fashion have heightened concerns about the fashion industry’s sustainability. Bacterial Cellulose (BC) has emerged as a promising biomaterial for sustainable applications in textiles and leather. However, dehydrated BC’s low thickness and high stiffness pose limitations, reducing its appeal in diverse fields, including fashion, healthcare, etc. To address this challenge, a Plasticized BC-based interpenetrating polymer network (IPN) leatherette is investigated using an innovative 2-in-1 thickening process and a following softening step using Glycerol. The thickening process involves a novel “self-thickening” technique based on cellulosic mercerization and a formation of interpenetrating polymer network structure using BC and Silica skeleton. The fabricated BC-based material exhibits unique IPN structure and significant increase in BC thickness to 1.83±0.10 mm (≈\approx16.64 times thicker), areal density to 2034.46±37.58 g/m2g/m2\hbox {g/m}^{2} (≈\approx16.33 times denser), moisture content of 31.09±0.48%, moisture regain of 45.12±1.01%, flexural rigidity of 3291.29±100.88 μ\upmuNm, and improved bending modulus of 6.48±0.20 MPa (≈\approx1035.27 times lower) compared to those of untreated BC. Furthermore, the durability of the Plasticized BC-based IPN leatherette is evaluated through five washing cycles, with the material retaining approximately 75.96%, 66.61%, 82.98%, and 77.39% of its unwashed thickness, areal density, moisture content, and regain, respectively. This study contributes to the value of BC-based materials in the textile and leather industries, offering a sustainable alternative to existing materials and production processes. Moreover, developing this novel 2-in-1 thickening process establishes a foundation for future research on BC functionalization in various applications, thereby contributing to sustainable development. Graphic Abstract
... Fabric softeners are made from double-chain cationic surfactants assembled into multi-or uni-lamellar vesicles (Oikonomou et al., 2017). The main components of popular softeners are long chain alkyl type cationic surfactants and silicone (Igarashi and Nakamura, 2018). Silicone based softeners are the most commonly used in the fashion industry, due to their superior smoothing effect (Hassabo and Mohamed, 2019;Zhou et al., 2020). ...
Article
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A Characteristic often found in textile products is softness. The compound widely used as softener is silicone compound. The aim of this research is to determine the properties that will be obtained from the type of fabric being processed by comparing the use of silicon types, namely amino-propyl-functional polydimethyl siloxane (PDMS) and blocked amino silicone to each fabric. Firstly, research was conducted by varying the pH of the finishing process. Determined optimum pH will be followed by determining concentration of 15–60 g/L for each type silicone. The experiments was carried out on pad- dry- cure method. The tests carried out include fabric stiffness, tensile strength, resistance to repeated washing and heat, yellowing effect, Fabric Touch Tester and Water Contact Angle testing. It was found that there was no significant influence of pH on the use of amino-propyl-functional polydimethyl siloxane and blocked amino silicone compounds, so the next process was carried out at pH 7. Increasing the concentration of the softener will provide a better softening effect and optimum concentration at 45 g/L for both types of fabric used. Blocked amino silicone has better resistance to repeated washing compared to amino-propyl-functional polydimethyl siloxane. Heat testing shows that differences in molecular structure have no influence on both fabrics. Fabric processed using amino-propyl-functional polydimethyl siloxane provides a yellowing effect. Amino-propyl-functional polydimethyl siloxane provides good hydrophilicity. The softness value of blocked amino silicone is better performance on cotton fabric.
... Due to their "waxy nature" [60], they can act as non-ionic surfactants [61] when used as additives during fiber processing. Many of the long-chain alcohols are used in the textile industry as surfactants, softeners (to increase viscosity), and lubricants [54,56,62,63]. ...
Article
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Cotton is used for the production of textiles, hygiene and cosmetic materials. During cultivation and technological processes, various types of substances (surfactants, softeners, lubricants, etc.) penetrate cotton, which can have a harmful effect on both the human body and the environment. The aim of this study was to analyze selected cotton products in order to identify the substances contained and to describe the potential possibilities of inducing textile contact dermatitis (CD). The impact of the identified compounds on the aquatic environment was also taken into account. Nine samples of cotton clothing and seven samples of cotton pads from various manufacturers were tested. Samples after extraction using the FUSLE (Focused Ultrasonic Liquid Extraction) technique were analyzed with GC/MS. Qualitative analysis was based on comparing mass spectra with library spectra using the following mass spectra deconvolution programs: MassHunter (Agilent), AMDIS (NIST), and PARADISE (University of Copenhagen). The parameter confirming the identification of the substance was the retention index. Through the non-target screening process, a total of 36 substances were identified, with an average AMDIS match factor of approximately 900 ("excellent match"). Analyzing the properties of the identified compounds, it can be concluded that most of them have potential properties that can cause CD, also due to the relatively high content in samples. This applies primarily to long-chain alkanes (C25-C31), saturated fatty acids, fatty alcohols (e.g., oleyl alcohol), and fatty acid amides (e.g., oleamide). However, there are not many reports describing cases of cotton CD. Information on the identified groups of compounds may be helpful in the case of unexplained sources of sensitization when the skin comes into contact with cotton materials. Some of the identified compounds are also classified as dangerous for aquatic organisms, especially if they can be released during laundering.
... Muthu and Rathinamoorthy 2021b;Sun et al. 2018;Igarashi and Nakamura 2017;Igarashi et al. 2016;Igarashi and Nakamura 2018). As a result, the stiffness and bending characteristics of leather-like BC/Brazilein/Glycerol are greatly improved for wearable purposes (flexural rigidity of 35.15±0.65 Nm and bending modulus of 135.54±2.51 ...
Article
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To deal with significantly raised environmental and health concerns due to discharges of numerous dangerous hazards of leather production, despite various excellent properties for leather alternatives, Bacterial Cellulose (BC) still faces obstacles in coloration and functionalization which can help alleviate drawbacks in dry state and expand applications. In this work, leather-like BC materials are successfully synthesized via a 3-in-1 textile finishing approach by using padding method that can confer three effects concurrently which are color, softness, and surface pattern. This finishing technique dehydrates mechanically BC membranes with high finishing efficacy, chemical saving for smarter manufacturing, and environmental protection. Leather-like BC/Brazilein/Glycerol possesses remarkable color strength K/S (5 times higher than that of other cellulosic textiles), impressive porosity, softness (flexural rigidity of 35.15±0.65μNm35.15±0.65μNm35.15\pm 0.65\,\mu \hbox {Nm}, bending modulus of 135.54±2.51MPa135.54±2.51 MPa135.54\pm 2.51\hbox { MPa}), amazing tensile strength (26.46±2.86MPa26.46±2.86 MPa26.46\pm 2.86\hbox { MPa}), high water vapor transmission rate of 759.40±40.46g/m2/24h759.40±40.46 g/m2/24h759.40\pm 40.46\hbox { g/m}^{2}/24\hbox {h}, relative resistance to water penetration (0.09±0.01bar0.09±0.01 bar0.09\pm 0.01\hbox { bar}). The leather-like BC yields added value to the fashion sector as a sustainable alternative for leather. The employment of the 3-in-1 finishing process has paved the way for future studies and applications on BC functionalization by using practical technologies in mass production (padding method) for various purposes. Graphical abstract
... The data elucidates the preference of experts for 18 different applied combinations of commercial softeners regarding parameters of hand feel and appearance (Table 1). Igarashi and Nakamura (2019) also applied softener on cotton threads and conducted a sensory evaluation where the threads were touched with bare hands in order to feel it and the softness was found to increase. It was clear from the table that 100 % Abrosil RUC (aminosilicone) softener ranked I in the list with weighted mean score of 4.6 (hand feel) and 4.8 (appearance). ...
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The Society of Krishi Vigyan has published its recent issue of the Journal of Krishi Vigyan for the benefit of the scientific community.
... Thus, considering the appeal to consumers, the use of softeners has diversified in recent years, with a focus on fragrance, deodorizing, and/or antibacterial qualities of the fabrics. Nonetheless, softeners still provide the primary function of softening clothes, a function that has remained unchanged over time [15]. ...
... Thus, considering the appeal to consumers, the use of softeners has diversified in recent years, with a focus on fragrance, deodorizing, and/or antibacterial qualities of the fabrics. Nonetheless, softeners still provide the primary function of softening clothes, a function that has remained unchanged over time [15]. ...
... The functionality of softeners as the appealing message to the consumers has diversified in recent years, with the market overflowing with a large number of products, are focused on fragrance, deodorizing, and/or antibacterial qualities. Nonetheless, the primary function -value for consumersoriginally provided by softeners is still the softening of clothes, which remains unchanged (Igarashi and Koichi, 2019). ...
Article
Softener plays an important role to improve the softness characteristic of fabric and it has significant effects on various fabric properties like hand feel, shade appearance and so on. In this experiment, different amount (1.0,
Article
Purpose Dehydrated bacterial cellulose’s (BC) intrinsic rigidity constrains applicability across textiles, leather, health care and other sectors. This study aims to yield a novel BC modification method using glycerol and succinic acid with catalyst and heat, applied via an industrially scalable padding method to tackle BC’s stiffness drawbacks and enhance BC properties. Design/methodology/approach Fabric-like BC is generated via mechanical dehydration and then finished by using padding method with glycerol, succinic acid, catalyst and heat. Comprehensive material characterizations, including international testing standards for stiffness, bending properties (cantilever method), tensile properties, moisture vapor transmission rate, moisture content and regain, washing, thermal gravimetric analysis, derivative thermogravimetry, Fourier-transform infrared spectroscopy and colorimetric measurement, are used. Findings The combination of BC/glycerol/succinic acid dramatically enhanced porous structure, elongation (27.40 ± 6.39%), flexibility (flexural rigidity of 21.46 ± 4.01 µN m; bending modulus of 97.45 ± 18.20 MPa) and moisture management (moisture vapor transmission rate of 961.07 ± 86.16 g/m ² /24 h; moisture content of 27.43 ± 2.50%; and moisture regain of 37.94 ± 4.73%). This softening process modified the thermal stability of BC. Besides, this study alleviated the drawbacks for washing (five cycles) of BC and glycerol caused by the ineffective affinity between glycerol and cellulose by adding succinic acid with catalyst and heat. Originality/value The study yields an effective padding process for BC softening and a unique modified BC to contribute added value to textile and leather industries as a sustainable alternative to existing materials and a premise for future research on BC functionalization by using doable technologies in mass production as padding.
Article
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Most softening agents, such as rinse cycle fabric softeners, used by consumers at home contain cationic surfactants that have two long alkyl chains as their main component. The softening mechanism on fibers, especially cotton, has not yet been scientifically established, despite the market prevalence of fabric softeners for decades. One explanation for the softening effect is that the friction between fibers is reduced. According to this explanation, the fiber surfaces are coated by layers of alkyl chains. Because of the low coefficient of friction between alkyl chain layers of low surface energy, the fibers easily slide against one another yielding softer cotton clothing. However, no direct scientific evidence exists to prove the validity of this explanation. The softening mechanism of cotton yarn is discussed in this paper. Bending force values of cotton yarn treated with several concentrations of softener are measured by bend testing, and cotton and polyester yarns are compared. Results indicate that increases in cotton yarn hardness after natural drying are caused by cross-linking among inner fibers aided by bound water. This type of bound water has been known to exist even after 2 days of drying at 25 °C and 60 % relative humidity. Yarn dried in vacuo is soft, similar to that treated with softener. Thus, some of the softening effect caused by fabric softeners on cotton can be attributed to the prevention of cross-linking by bound water between cotton fibers.
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Twelve types of cellulosic fibre, including natural, regenerated, and chemically-modified fibres, were studied with regard to their moisture sorption and desorption isotherms. X-ray diffraction patterns of the fibres are presented. There are 61 references.
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Proceedings of the first Japan/Australia joint symposium held in Kyoto, Japan, 10-12 May, 1982 are published in book form: the full texts of 32 pages are given and each is abstracted in this issue of World Textile Abstracts.
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Main ingredient of domestic fabric softeners is a double chain cationic surfactant. It is suggested that the performance is related to phase condition or molecular orientation of the cationic surfactant or the compound used together by many experiments. A polyether modified silicone (PMS) makes a particle size of a fabric softener smaller, and tribological characteristics lower. The particle combined with PMS improves texture of clothes and their durability as well as maintains their appearance by penetrating deep into filaments uniformly. Especially, lower modified and highly polymerized PMS is a suitable material for the compound. It is presumed that the PMS is finely distributed in the particle.
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二本鎖型カチオン界面活性剤 (ジオクタデシルジメチルアンモニウムクロリド;DODAC) は, 柔軟仕上げ剤やヘアリンスの主剤として用いられている。その親水性表面への吸着状態を電子顕微鏡, 原子間力顕微鏡により観察した。親水化処理をほどこしたニトロセルロース膜にDODACの水中分散液を滴下し, ネガティブ染色法を用いて電子顕微鏡観察を行った。超音波処理を行わない試料に関しては, 膜上には平均直径250nmの多重層ベシクルが膜上に吸着していた。超音波処理を施した試料は, 一枚膜型ベシクルを形成する。マイカ基板上にDODAC分散液を滴下して, 原子間力顕微鏡により吸着したベシクルの形態および厚さを測定した。超音波処理を行ったベシクルは, 乾燥後の厚さが4nmとなった。これはベシクルの内水相が乾燥とともに外部へ流出し, 閉殻構造がつぶれて, さらに二分子膜が指組構造をとっていると考えられる。これらの結果よりDODACは単分子の状態で吸着するのではなくベシクルの状態で親水性表面に吸着していることが明らかとなった。
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Knitted fabrics were treated with household softeners. The mechanical and surface properties as well as the thermal and moisture transport properties of the fabrics were measured. The use of softeners decreased the friction between fibers, the fabrics treated with softeners became softer and the primary fabric hand values (NUMERI, FUKURAMI, SOFUTOSA) increased slightly. Therefore, the wearing comfort on winter of these fabrics seemed to increase. But cotton fabric exhibited polyester fabric-type hydropyobic properties and the wearing comfort on summer seemed to decrease. In the case of washing with detergent that contains softener, the softener did not adequately reduce the inter-fiber friction that increases when a fabric is washed by detergent alone, indicating that it is most effective to add softener after the wash cycle.
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The ζ-potential of synthetic fibers, polyacrylonitrile (Cashimilon), polyester (Tetoron), polypropylene (Pylen), polyvinylalcohol (Vinylon) and polyamide (Nylon 6), was measured in surface active went (anionic agents SDS and cationic agent DPB) solutions at neutrality and at alkalinity. The charge density and the amount of surface active agents adsorbed per unit area of the fiber surface were calculated from the ζ-potential of the fibers.From the effect of the concentration of surface active agent on the ζ-potential, it is suggested that the adsorption of anionic agent SDS on these fibers takes place mainly by the van der Waals' force, but the adsorption of cationic agent DPB on these fibers takes place mainly by the electrostatic attractive force.The amount of surface active agent adsorbed per unit area of the fiber surface increased with the increase of the concentration of those agents, and the greater the increase was, the more hydrophobic the fiber in the order of polyvinylalcohol, polyaerylonitrile, polyamide, polyester and polypropylene.Also the amount of SDS adsorbed per unit area of the fiber surface in aqueous neutral solution was greater than that in aqueous alkali solution, but the amount of DPB adsorbed per unit area of the fiber surface in aqueous alkali solution was greater than that in aqueous neutral solution.
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The appearance, growth, and structure of a cotton fiber are described, and photomicrographs and electron micrographs are used to illustrate both gross and fine features of the cell wall morphology. Heretofore, microscopy of the fiber has been limited to the use of dispersion, swelling and staining methods, in plain and polarized light. The development during the present study of methods for isolation of individual components of the cell wall for purposes of electron microscopy has permitted interesting observations with the light microscope. Quantitative measurements of shrinkage in the isolated primary wall of the cotton fiber during mercerization confirm its restrictive influence on the fiber during swelling in various agents. Electron microscope studies have been made on isolated primary wall fragments which have been purified by removal of noncellulosic constituents by extraction. These have revealed that the cellulosic portion of the membrane is a network of fibrils interlaced in a sort of fabric in which the general system of orientation is axial on the outer surface and transverse on the inner surface. The cellulose framework is impregnated with a complex of waxes, pectinaceous, and proteinaceous substances. The first layer of secondary thickening, called the "winding layer," has been isolated from 17-day old cotton fibers and photographed with both optical and electron microscopes. It is revealed to be a continuous sheet or layer made up of alternating bands of fibril bundles which spiral about the fiber at an angle. The wider bands have a closely packed parallel arrangement of fibrils while the narrower bands which connect them consist of two systems of fibrils at right angles to one another in an open-weave pattern. Electron micrographs of fragments of the main body of the secondary wall show an entirely different pattern of fibril arrangement from either the primary wall or the winding layer.