Method for preventing yellowing of wool fibers, performing bright dyeing, and imparting wash resistance

Abstract

To impart washing resistance by improving shrink-resistance in an environment-friendly processing method; and to provide a yellow discoloration and clear dyeing treatment method of wool fibers for obtaining a light-proof and highly-clear product.SOLUTION: A yellow discoloration and clear dyeing treatment method of wool fibers to which washing resistance is imparted is characterized as follows: a synthetic polymer is coated on wool fibers to which a bleaching treatment is applied, and an impregnation treatment of UV absorber is applied to the synthetic polymer.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention aims to prevent the photo-yellowing of wool fibers, enhance the light resistance and perform bright dyeing. Furthermore, it aims to coat the wool surface with a light-resistant synthetic polymer to improve the shrink-proof property and impart wash resistance.

Background Art

[0002] Compared with cotton and synthetic fibers, wool fibers are colored in a cream color, and it has been difficult to achieve bright dyeing with light resistance. In recent years, products with high whiteness and vivid color tones have been demanded for wool fibers as well. However, due to the wool protein fibers, it has been extremely difficult and remains the biggest problem that has not been technically solved in terms of protein chemistry yet.

[0003] Regarding the improvement of the whiteness of wool fibers, in the past, it has mainly been carried out through the processes of scouring and bleaching. As bleaching methods, oxidative bleaching using an oxidizing agent and reductive bleaching using a reducing agent have been performed. As oxidative bleaching, chlorine bleaching using bleaching powder, sodium hypochlorite, and sodium chlorite, and hydrogen peroxide bleaching are the mainstream. There are also many methods such as one-bath scouring and bleaching with peracetic acid, perboric acid, etc., and other methods such as isocyanuric trichloride bleaching, ozone bleaching, potassium permanganate bleaching, and chloramine bleaching. On the other hand, as reductive bleaching, hydrosulfite bleaching, thiourea dioxide, and sulfinic acid derivatives are mentioned. In many cases, oxidative and reductive bleaching are used in combination, and a fluorescent whitening agent treatment is also performed. However, the light fastness is very poor and the hue change is drastic. At the same time, this treatment has no wash resistance, and since the chemical reaction on the wool fibers is severe, the fibers tend to become brittle. As a result, there is a limit to bright dyeing.

[0004] The biggest problem with wool fibers is that the research and development status regarding brightening, bleaching, and bright dyeing was reported at the 11th International Wool Research Conference held in Leeds in September 2005 (see Non-Patent Document 3). However, research and development on bright and pure white wool has been ongoing for the past 40 years, but there is still no solution. Even at the world's wool research institutes, namely the Commonwealth Scientific and Industrial Research Organization (CSIRO) in Australia, the German Wool Research Institute (WDI), and the New Zealand Wool Research Institute (Canesis), this is an area that has not been resolved, and the situation has not yet yielded satisfactory results even to this day (see Non-Patent Document 3).

[0005] Research on the mechanism of photoyellowing of wool and silk fibers is old and still in the process of being solved. It has been reported that among various amino acids of wool proteins, the decomposition of tryptophan, tyrosine, phenylalanine, and cystine is involved. As photoxidation products of tryptophan, kynurenine and 3-hydroxykynurenine have been detected by HPLC (High Performance Liquid Chromatography). For tyrosine and phenylalanine, the polymerization decomposition products of o-, m-, p-tyrosine and DOPA (3,4-dihydroxyphenylalanine) are involved, causing photoyellowing.

[0006] Fluorescent brighteners act strongly as photosensitizers. When wool that has been bleached or fluorescently brightened is irradiated with light, cystine, methionine, tryptophan, tyrosine, and histidine residues are photooxidized and decomposed, and kynurenine, 3-hydroxykynurenine, and N-formylkynurenine are generated, significantly promoting photoyellowing (see Non-Patent Document 3).

[0007] Analysis of the epidermal structure of wool leads to the present invention. By decoding its epidermal structure, the foundation of the present invention is created.

[0008] The epidermal tissue of wool is complex. The outermost epidermis is called the epicuticle, with a thickness of 5 nm and a cystine content of 12%. Below it is the exsocuticle-A with a cystine content of 35%. Further, the exsocuticle-B with a cystine content of 15% overlaps, and together they exist with a thickness of 0.3 μm. At the bottom, the endocuticle with a cystine content of about 3% and extremely low cystine content forms a structure with a thickness of 0.2 μm. In the cuticle of the entire epidermal tissue, a structure with a thickness of 0.5 μm has been reported (see Non-Patent Documents 4 and 5).

[0009] The cuticle that constitutes the epidermis of wool is somewhat resistant to oxidants, reductants, enzymes, and ultraviolet rays, protecting the interior of the wool fiber. However, when the cuticle is damaged, the wool fiber becomes extremely brittle, and the original properties of the wool change and deteriorate.

[0010] There is an experiment by J.A. Swift who analyzed the epidermis of hair histochemically (see Non-Patent Document 6). The hair was treated with tryptophan enzyme for 9 hours, then with tyrosine enzyme for 230 hours, with pronase enzyme for 120 hours, and finally with papain enzyme / dithiothreitol for 1 hour and papain / dithiothreitol for 72 hours. It is reported that the tissue remaining as the final residue is the exsocuticle (Exsocuticle-A, -B) with a high cystine content. Thus, the tissue with a high cystine content covers the wool surface and protects against external attacks.

[0011] Regarding the ultraviolet (UV) irradiation of sunlight, in the UVA (wavelength, 380 - 320 nm) and UVB (wavelength, 320 - 280 nm) regions, it has been reported that, as pointed out by Atsushi Ito and Yoshitada Iwata, the cystine in the surface tissue of hair greatly contributes to preventing photo-brittleness (see Non-Patent Documents 1 and 2).

[0012] Methods for coating the surface of wool with synthetic polymers have been mainly carried out at the Western-Regional Research Laboratory (WRRL) of the United States Department of Agriculture from 1963 to 1965 (see Patent Document 1). In recent years, the inventors of the present application have developed a continuous processing apparatus using a mangle. The basic technology consists of a liquid / liquid interfacial polymerization method, in which nylon polymer is polymerized at the interface between an aqueous solution of hexamethylenediamine and a solution of sebacic acid dichloride dissolved in a silicone-based solvent, which is a novel solvent, to coat the surface of wool fibers with nylon 610, which is a nylon polymer, and is a novel anti-shrinkage processing method for preventing entanglement between fibers during washing (see Patent Documents 2 and 3). However, due to problems such as environmental issues, the use of many organic solvents is regulated by environmental protection laws, leaving problems for industrialization using organic solvents.

[0013] Today, silicone-based solvents are commercially available from Green Earth Ltd (USA) and Shin-Etsu Chemical Co., Ltd. as novel solvents and are used as novel environmentally friendly dry-cleaning solvents to replace perchloroethylene. An interfacial polymerization method using this novel silicone-based solvent has been developed and industrialized and is disclosed in Patent Documents 2 and 3.

[0014] As described above, resin processing treatment of wool fibers has been known since around 1964, and attempts at industrialization have been made. However, due to the use of solvents and the recent environmental conservation, industrialization has been hindered. However, in recent years, it has become possible to industrially perform interfacial polymerization treatment using a novel silicone-based solvent, enabling anti-shrinkage treatment of wool fibers and impregnation treatment of nylon polymers with ultraviolet absorption, and for the first time, it has become possible to develop wool products having the wash resistance and light resistance of the present invention.

Prior Art Documents

Non-Patent Documents

[0015]

Non-Patent Document 1

[0016] [Patent Document 1] U.S. Patent No. 3,078,138 [Patent Document 2] Japanese Patent No. 5,214,181 [Patent Document 3] Japanese Patent No. 5,629,794 [Summary of the Invention] [Problems to be Solved by the Invention]

[0017] The biggest drawbacks of wool fibers are: 1) felting shrinkage "shrinking" during home laundering, 2) the creamy coloring of the wool fibers themselves, 3) yellowing due to sunlight irradiation, 4) difficulty in achieving durable whitening, etc. Resolving these drawbacks has been an issue over the years. In particular, in shrink-proof processing to impart washability, chlorine shrink-proofing based on chlorine agents has been the norm until today, but it leaves problems from the perspective of environmental protection due to the release of adsorbable organic chlorine compounds (AOX). Furthermore, it hydrophilizes and destroys the epidermal tissue of wool fibers, intensifying the movement of "water" and the movement of "heat", reducing the original heat retention and comfort of wool.

[0018] Also, the photo-oxidation of wool fibers always leads to yellowing, making it impossible to obtain a vivid color development. Compared with cotton fibers, polyester fibers, etc., the whiteness of the raw fibers is inferior, and bright dyeing with light resistance cannot be achieved, hindering the application of wool fiber clothing, especially for women's and children's clothing.

[0019] In order to make a great contribution to the wool industry, the present invention provides an environmentally friendly treatment method to solve the above problems, improve shrink-proof properties to impart washability, and prevent yellowing and achieve bright dyeing of wool fibers to obtain products with high light resistance and vividness.

Means for Solving the Problems

[0020] The treatment method of the present invention is a method for preventing yellowing and bright dyeing of wool fibers with imparted washability performance, which is characterized by coating bleached wool fibers with a synthetic polymer and impregnating the synthetic polymer with an ultraviolet absorber. This coating of the synthetic polymer preferably polymerizes hexamethylenediamine and sebacoyl dichloride on the surface of the wool fibers by an interfacial polymerization method to coat nylon 610, and the ultraviolet absorber is preferably a benzophenone-based ultraviolet absorber or a benzotriazole-based ultraviolet absorber.

[0021] Moreover, the bleaching treatment is preferably a hydrogen peroxide / sodium hydrosulfite bleaching treatment. Further, the dyeing treatment of the wool fibers subjected to the above treatment is preferably a low-temperature dyeing treatment at a dyeing temperature of 85°C ± 5°C.

[0022] The wool fibers to be subjected to the above treatment method are natural keratin fibers composed of one or more of wool, cashmere, mohair, angora, and camel, and wool fibers without damage to the surface structure are preferably used. And this wool fiber is preferably a fiber group composed of any of a woven fabric, a knitted fabric, a non-woven fabric, a sliver, and a twisted yarn, which is composed of a blended fiber or a ply yarn of the above natural keratin fiber, or a synthetic fiber composed of one or more of nylon fiber, acrylic fiber, and polyester fiber.

Advantages of the Invention

[0023] The epidermis of wool fibers is hydrophobic. When coating hydrophilic polymers on wool fibers, the wool surface needs to be subjected to chemical treatments such as acid chlorine treatment before it can be hydrophilized, and then the hydrophilic polymer can be coated on the surface of the wool fibers. Conversely, when coating hydrophobic polymers, without modifying the wool fiber surface, as in the present invention, it is possible to coat the hydrophobic polymer on the wool fiber surface using a non-aqueous solvent composed of a solvent.

[0024] The treatment method of the present invention is a treatment method for wool fibers that can improve light resistance, prevent yellowing, increase whiteness, and perform bright dyeing while maintaining the original hydrophobicity without damaging the epidermis of the wool fibers, and obtain products with high light resistance and high vividness. Further, by coating the epidermis with a synthetic polymer, it is a method to improve shrink resistance and impart wash resistance. Thus, the method of the present invention creates new wool products and contributes to the wool industry.

Brief Description of the Drawings

[0025]

Figure 1

Figure 2

Figure 3

Mode for Carrying Out the Invention

[0026] The treatment method of the present invention coats a synthetic polymer on bleached wool fibers to improve shrink resistance and impart washability, and at the same time, by subjecting the synthetic polymer to a treatment containing an ultraviolet absorber, it prevents yellowing and performs vivid dyeing treatment.

[0027] Incidentally, the wool fibers targeted by the processing method of the present invention have, as their characteristic, an ultraviolet shielding effect in the UV-A region of ultraviolet rays in the 400 nm to 300 nm region and the UV-B region of 300 nm to 290 nm. Nylon, rayon, and cotton have little such shielding effect, and a comparison of their shielding effects is shown in Fig. 1. Wool fibers have a cystine content extremely high compared to the entire fiber in their surface structure, particularly in the epicuticle and exocuticle of the epidermal tissue, showing a shielding effect against sunlight and having a low transmittance of UV-A and UV-B. Thus, the reason why the ultraviolet blocking effect of wool itself is high compared to other fibers is that there are epicuticle and exocuticle-A and B with a high cystine content in the outermost shell of wool, and this epidermal tissue retains the function of protecting the internal tissue of wool fibers. Fig. 2 is an enlarged photograph cited from Non-Patent Document 7, showing the surface of wool fibers (Australian Merino wool) coated with a nylon polymer by an interfacial polymerization treatment method, and then an enlarged (×380) optical micrograph of a nylon tube created by dissolving and removing the internal protein tissue of the wool fibers with an aqueous sodium hydroxide solution, which is a replica of the wool epidermal tissue and shows the state of the nylon polymer adhered to the scales of the wool fibers. Table 1 shows the tissue compositions of the epidermal tissue (cuticle) and the internal tissue (cortex). In this tissue composition of wool, the total thickness of the scales, which are the epidermal tissue, is 0.5 μm, but exocuticle-A and B with a high cystine content are 0.3 μm, accounting for about 60%. As shown in the above enlarged photograph, the scales of wool fibers have a structure that overlaps several times like the skin of bamboo shoots, protecting the inside of the wool fibers and enhancing the ultraviolet shielding function. However, the epidermal tissue (cuticle) is a tissue with a thinner thickness compared to the internal tissue (cortex).

Table 1

[0028] As described above, wool fibers have an ultraviolet blocking function in the epidermal tissue, but yellowing due to light cannot be avoided. Particularly when the epidermal tissue (cuticle) is damaged, the embrittlement of the wool fibers becomes severe, and the original properties of the wool change and deteriorate.

[0029] Also, as described above, Patent Documents 2 and 3 disclose a novel shrink-proof processing method in which nylon polymer, a synthetic polymer, is coated on wool fibers to prevent entanglement between fibers during washing. In this method, the nylon polymer, which is the synthetic polymer to be coated, absorbs ultraviolet rays and has a function of blocking ultraviolet rays. However, coating with only the nylon polymer is insufficient to prevent yellowing of wool fibers, and yellowing due to light progresses. Therefore, even when bleaching treatment was performed and vivid dyeing was applied, a vivid color tone could not be maintained.

[0030] In the present invention, by incorporating an ultraviolet ray-absorbing agent into the synthetic polymer that coats wool fibers, the synergistic effect between the wool and the synthetic polymer to be coated prevents yellowing of the wool and maintains the color tone of the vivid dyeing applied. To confirm this ultraviolet ray-blocking effect, the results of measuring the ultraviolet ray absorption performance when an ultraviolet ray-absorbing agent was incorporated using nylon 610 as the synthetic polymer are shown in FIG. 3.

[0031] Figure 3 shows the results of measuring the spectral transmittance (%) in the region from 400 nm to 200 nm using nylon 610 as the synthetic polymer and using "UV-FAST W LIQ." manufactured by HUNTSMAN Corp. and "Shine Guard W-51 new" manufactured by Senka Corporation as the ultraviolet absorbers. The method for preparing the measurement samples was as follows: a sebacic acid dichloride solution with a concentration of 0.1 mol / L in a silicone-based solvent was applied to the surface of the glass for the preparation used in optical microscope observation, and then an aqueous solution of hexamethylenediamine with a concentration of 0.1 mol / L was applied thereon to form a nylon 610 polymer on the glass surface to prepare Sample B. Then, Sample B was impregnated with "UV-FAST W LIQ." manufactured by HUNTSMAN Corp. and "Shine Guard W-51 new" manufactured by Senka Corporation to prepare Samples C and D. From the results shown in Figure 3, it was confirmed that the nylon polymer itself also has an ultraviolet absorption effect, and furthermore, when impregnated with an ultraviolet absorber, the effect becomes significantly higher, indicating that the ultraviolet blocking effect of the ultraviolet absorber is high.

[0032] The wool fibers that are the object of the treatment method of the present invention belong to animal hairs and are natural keratin fibers such as wool, cashmere, mohair, angora, and camel. They may be fibers alone or combined by blending or twisting, and may further be blended or twisted with synthetic fibers such as nylon fibers, acrylic fibers, and polyester fibers.

[0033] As the synthetic polymer for coating the wool fiber, a nylon polymer is preferred. As the coating method, it is preferable to perform polymerization by an interfacial polymerization method on the surface of the wool fiber to simultaneously generate and coat the synthetic polymer, and the methods described in Cited Documents 2 and 3 are applied. This method utilizes liquid / liquid interfacial polymerization and generates nylon polymer at the interface between an aqueous solution phase and a solvent phase that does not mix with it. In this case, as the solvent that does not mix with water, the above-mentioned environmentally friendly silicone-based solvent is used. In the case of a nylon polymer, an aqueous solution of a diamine compound is used as the aqueous solution phase, and a solution in which a dibasic acid chloride compound is dissolved in a silicone-based solvent is used as the solvent phase. Nylon 610 using hexamethylenediamine as the diamine compound and sebacic acid dichloride as the dibasic acid chloride is a preferred synthetic polymer.

[0034] As the ultraviolet absorber to be impregnated, benzophenone-based and benzotriazole-based ultraviolet absorbers are preferably used. These ultraviolet absorbers are widely commercially available from various companies, and these ultraviolet absorbers can be used. In particular, Shine Guard W-51 new (manufactured by Senka Corporation) and UV-FAST W LIQ. (manufactured by HUNTSMAN) belonging to the benzotriazole-based ultraviolet absorbers are recommended.

[0035] Also, as the bleaching method of the wool fiber, various bleaching treatments described above can be applied, but hydrogen peroxide / hydrosulfite bleaching treatment is preferred, and dyeing is preferably low-temperature dyeing treatment at a dyeing temperature of 85°C ± 5°C.

[0036] Hereinafter, it will be described in more detail by examples, but the main measurement methods and criteria are as follows. (Whiteness measurement) Using AuColor-TX (Comuter Colur MatchingSystem, CCM) manufactured by Kurashiki Boseki Co., Ltd., measure L: lightness, a: redness, b: yellowness, and according to the whiteness measurement method of JIS L 1916-20 fiber products, whiteness formula (WL = L * +3a * -3b* ) was calculated using (Lightfastness test) In accordance with JIS L 0842 method, irradiation was carried out with a carbon arc lamp for 20 hours and 40 hours, and the fading was compared on a blue scale. (Color fastness to washing) In accordance with JIS L 0844 - A method, at 50 °C for 30 minutes, using a launder - o - meter 0 - meta -, the degree of contamination on the attached white cloth (cotton cloth) was compared on a gray scale. (Washing shrinkage test) A washing test was carried out in accordance with the Wool Mark test method TM 31 based on ISO 6330 5A and 7A. As the calculation formula, the relaxation dimensional change rate, felted dimensional change rate, and total dimensional change rate in the width (WS) and length (LS) directions were calculated separately for each direction by the following formulas. Relaxation dimensional change rate (%) = (RM - OM) / OM X 100 Felted dimensional change rate (%) = (FM - RM) / RM x 100 Total dimensional change rate (%) = (FM - OM) / OM x 100 OM = Original length RM = Measured value after relaxation treatment FM = Measured value after felting treatment Area dimension (%) = WS + LS Note: From the above relational expressions, - indicates shrinkage.

[0037] (Reference Example 1 Bleaching treatment) Using 1 / 60 Nm worsted yarn made of wool from Australian Merino sheep, a knitted fabric sample was made with a 14G sock knitting machine and used as a series of experimental samples for this case. The sample was subjected to oxidative - reduction bleaching in a cheese dyeing machine. As the bleaching conditions, a standard bleaching method using hydrogen peroxide and hydrosulfite was adopted. The standard concentration prescription (1 - fold) is a condition based on the general - purpose conditions widely used in the industry and without problems in wool bleaching products. The processing chemical concentration was changed to an integer multiple based on hydrogen peroxide (35%) 10 g / L, hydrosulfite 2% owf, and formic acid (75%) 10 ml / L, and the whiteness was measured by setting the processing conditions. The whiteness was measured according to the method for measuring the whiteness of textile products specified in JIS L 1916-2000. The device used was a computer color matching CCM device manufactured by Kurashiki Boseki Co., Ltd., and the whiteness, WL = L * +3a * -3b * was calculated using the formula. The bleaching treatment conditions are summarized in Table 2 and shown below

Table 2

Table 3

Table 4

[0038] (Reference Example 2: Synthetic Polymer Coating Treatment) According to Reference Example 1, oxidation / reduction bleaching was carried out under the conditions of standard concentration (1-fold), and then a sample was prepared by coating nylon 610 as a synthetic polymer coating treatment by the interfacial polymerization method. The interfacial polymerization method was carried out in accordance with Patent Documents 2 and 3 as a substantial industrial method for coating nylon 610 on the surface of wool fibers. As the polymerization method, liquid / liquid interfacial polymerization was utilized to form nylon 610 at the interface between an aqueous solution phase and a solvent phase that does not mix with water. As a solvent that does not mix with water, environmentally friendly Shin-Etsu Silicone KF-96-100cs (manufactured by Shin-Etsu Chemical Co., Ltd.) was used. The wool fiber sample used was a knitted fabric knitted on a 14G sock knitting machine from merino yarn of 1 / 60 Nm count made of Australian merino wool with a fineness of 18.5 μm as the sample. (First Step) The knitted fabric was continuously immersed in a first bath containing 0.1 mol / L of hexamethylenediamine aqueous solution with 0.1 mol / L of sodium hydroxide and 0.1 g / L of penetrant SSK-15A (manufactured by Matsumoto Yushi Co., Ltd.) at 40 °C for 30 seconds, and then squeezed with a mangle to a squeezing ratio of 60%. (Second Step) Next, the knitted fabric was immersed in a solvent solution prepared by dissolving sebacic acid dichloride in Shin-Etsu Silicone KF-96-100cs (manufactured by Shin-Etsu Chemical Co., Ltd.), a safe silicone-based solvent that has no impact on the human body and the working environment, to a concentration of 0.1 mol / L at room temperature for 20 seconds, and then squeezed with a mangle to a squeezing ratio of 60%. (Third Step) Next, it was washed with water at room temperature and squeezed. (Fourth Step) At room temperature, it was washed with water using a 1% aqueous formic acid solution and then squeezed with a mangle. (Fifth Step) It was washed with warm water at 45 °C and then dried with hot air at 80 °C.

[0039] To evaluate the whiteness and lightfastness properties of wool knitted fabrics coated with a synthetic polymer after interface overlapping treatment, the hydrogen peroxide / hydrosulfide bleaching conditions of Reference Example 1 were carried out, and then carbon arc lamp irradiation was performed on the wool knitted fabric coated with nylon 610 by interface overlapping treatment for 20 hours and 40 hours to measure the change in whiteness and examine the influence on whiteness and lightfastness properties. The results are shown in Table 5, and the results of the synthetic polymer-coated wool knitted fabric by interface overlapping treatment without bleaching treatment are shown in Table 6 as Comparative Example 2.

Table 5

Table 6

[0040] (Example 1) As benzotriazole-based ultraviolet absorbers well-received in the dyeing industry, Shin Guard W-51 New (manufactured by Senka Corporation) and UV-FAST W LIQ. (manufactured by HUNSTMAN Corp.) were selected, and wool fibers were treated with ultraviolet absorbers under the following treatment conditions. Shin Guard W-51 New was dissolved in an aqueous solution adjusted to pH 6.0 at 5% owf based on the fiber weight, and using a wool knitted fabric that had been subjected to the bleaching treatment and the coating of the synthetic polymer by interfacial polymerization in Reference Example 2 above in a basket carrier cheese dyeing machine at 40°C for 60 minutes, the ultraviolet absorber treatment was carried out. On the other hand, UV-Fast W LIQ. was dissolved in an acetic acid acidic aqueous solution of pH 4 at 4% owf based on the fiber weight, and the same wool knitted fabric that had been subjected to the above treatment was treated in the dyeing machine at 80°C for 20 minutes, and the ultraviolet absorber treatment was carried out. After the ultraviolet absorber treatment, irradiation was carried out with a carbon arc lamp for 40 hours, the whiteness and lightfastness of this wool knitted fabric were evaluated, and the treatment effect of the ultraviolet absorber was investigated. The results are shown in Table 7.

Table 7

[0041] Using an aqueous solution that does not contain Shin Guard W-51 New and UV-FAST W LIQ., which are ultraviolet absorbers, the same treatment as in Example 1 was carried out, and the results of irradiation with a carbon arc lamp for 40 hours are shown in Table 8 as Comparative Example 3.

Table 8

[0042] For the wool knitted fabric in Table 7, the whiteness (WL) in the untreated bleached state was 41.14. When the bleaching agent concentration conditions in the hydrogen peroxide / hydrosulfite bleaching treatment were set to standard (1.0 times), 1.5 times, 2.0 times, and 3.0 times, the higher the concentration, the more the whiteness improved. However, when treated with each ultraviolet absorber, there was no significant difference in the lightfast performance between these two ultraviolet absorbers.

[0043] (Example 2) To perform wool pastel dyeing, Lanasol Yellow 4G (manufactured by HUNSTMAN Corp.) was selected as the reactive dye, and Kayacyl Rhodamone FB (manufactured by Nippon Kayaku Co., Ltd.) was selected as the acid dye. Wool knitted fabric that had been bleached, polymer film-treated by the interfacial polymerization method, and treated with an ultraviolet absorber according to the method described in Example 1 was deniered to produce wool yarn, which was used as a dyeing sample. This wool yarn was 2 / 60 Nm count, and 10 g of this wool yarn was dyed in a 12-color Colur Pet dyeing machine at a bath ratio of 1:30 under the following dyeing conditions. Table 9 shows the detailed dyeing treatment conditions for Lanasol Yellow 4G, and Table 10 shows the detailed dyeing treatment conditions for Kayacyl Rhodamine FB.

Table 9

Table 10

[0044] For dyeing wool fibers, the dyeing temperature is very important. At the boiling temperature, thermal yellowing occurs and the fiber strength also decreases. In particular, in pastel dyeing, the dyeing temperature is crucial. In this sense, low-temperature dyeing of wool fibers is an important factor. When the dyeing temperature exceeds 85°C, the yellowing of wool accelerates, resulting in a decrease in lightness. Therefore, dyeing at 85°C ± 5°C prevents yellowing due to ultraviolet rays and yellowing and embrittlement due to the dyeing temperature, leading to the success of the development of this case.

[0045] After pastel dyeing, in accordance with the JIS L 0842 method, exposure was carried out by irradiating with a carbon arc lamp for 20 hours and 40 hours, and the lightfastness (grade) was evaluated using a blue scale. Table 11 shows the results of the 20-hour irradiation, and Table 12 shows the results of the 40-hour irradiation. The lightfastness (grade) is shown together with a comparative example in which only the ultraviolet absorber treatment was performed and the synthetic polymer coating treatment was not performed.

Table 11

Table 12

Table 13

Table 14

[0046] From the comparison between Example 2 and Comparative Examples 4 to 7, it was found that the light fastness was significantly improved by the combined use of the synthetic polymer coating treatment by interfacial polymerization treatment and the ultraviolet absorber treatment. Generally, in the dyeing industry, it is said that if the light fastness is 0.5 to 1.0 grades higher than the general normal dyeing fastness standard, it is the best result. However, with the method of the present invention, a result of 1.0 to 1.5 grades higher was obtained in the 20-hour irradiation.

[0047] (Example 3) The wool knitted fabric that has been subjected to bleaching treatment, synthetic polymer film treatment by the interfacial polymerization method, and ultraviolet absorber treatment according to the method described in Example 1 is dyed with each of the dyes Procion (manufactured by ICI), Lanasol (manufactured by HUNSMAN), which are reactive dyes, Kayacryl Rhodamine FB and Kayanol Milling (manufactured by Nippon Kayaku Co., Ltd.), which are acid dyes, Supralan (manufactured by DyStar), and Kayarus (manufactured by Nippon Kayaku Co., Ltd.), which is a direct dye. The fastness of the sample is evaluated by the JIS L 0844-A method for washing fastness, and the washing fastness (grade) for each dye is recorded in Table 15 as the evaluation result. In the table, "untreated" indicates a comparative example in which a wool knitted fabric that has been subjected only to the bleaching treatment described in Reference Example 1 without the synthetic polymer film treatment and the ultraviolet absorber treatment is dyed. IFP indicates the synthetic polymer coating treatment by the interfacial polymerization method as described above. [Table 15] In addition, shrinkage resistance is required as a washability for wool products, and a test for washing fastness is also required. Due to the adoption of low-temperature dyeing at 85°C from the perspective of bright dyeing, washing fastness is important. As shown in Table 15, even when nylon 610 is coated on the wool surface as a synthetic polymer, regardless of the type of dye selected, the fastness is comparable to that of untreated wool, and bleeding of the dye from the wool fibers was not observed.

[0048] (Example 4) Similar to Example 3, the wool knitted fabric that has been subjected to bleaching treatment, synthetic polymer film treatment by the interfacial polymerization method, and ultraviolet absorber treatment is dyed with Lanasol Blue, 3G, and Kayacyl Rhodamine FB. As the washability of the knitted fabric, shrinkage was evaluated in accordance with IWS TM31. The evaluation results are shown in Table 16. Even after bleaching, interfacial polymerization, and dyeing treatments, good results were obtained with an area shrinkage rate of 0.56% (elongation) and -2.97% (shrinkage) in the felt shrinkage rate. [Table 16]

[0049] (Comparative Example 8) After performing the bleaching treatment according to Reference Example 1, the washing test results of the samples dyed with Lanasol Blue, 3G, and Kayacyl Rhodamine FB are shown in Table 17 as Comparative Example 8. [Table 17] From the results of Tables 16 and 17, it was confirmed that the significant improvement in the washing resistance performance was mainly contributed by the synthetic polymer coating treatment on the surface of the wool fibers.

[0050] (Examples 5, 6) The washing resistance results of the wool knitted fabrics subjected to each treatment including individual treatments by the methods described in the above-mentioned reference examples and examples are shown in Table 18 together with the comparative examples. And the results of the washing resistance of the untreated wool knitted fabric that was only scoured are shown in Table 19 as Comparative Example 12. The washing test was carried out in accordance with Wool Mark Test Method TM 31 based on ISO 6330 using a wool knitted fabric. The sample was washed for 60 minutes in a washing machine, SANYOSW-102S(H) Compact (manufactured by former Sanyo Electric Co., Ltd.) with the washing intensity of "strong" cycle, and the shrinkage rate was evaluated. [Table 18] Bleaching in the treatment content indicates bleaching treatment, IFP indicates synthetic polymer film treatment by the interfacial polymerization method, UV indicates ultraviolet absorber treatment, dyeing indicates dyeing treatment, irradiation indicates irradiation treatment with a carbon arc lamp. The bleaching treatment method was according to Reference Example 1, the IFP treatment method was according to Reference Example 2, the UV treatment method was the method in Example 1. The treatment contents of Examples 5 and 6 were carried out by the respective treatment methods in Example 2 and were subjected to the washing test. From the results shown in Table 18, it was confirmed that, similar to Example 4, the contribution of the synthetic polymer coating treatment on the surface of the wool fibers was significant. Table 19 shows the results of the washing test carried out according to the method of ISO / IWS TM31 using the scoured untreated wool knitted fabric as Comparative Example 12.

Table 19

Industrial Applicability

[0051] The biggest research and development of wool fibers is to develop Whiter, Brighter Wools. This problem has not obtained satisfactory results in terms of basic research or industrialization, even in the world's wool research institutes such as the CSIRO in Australia, the DWI in the German Wool Research Institute, and Canesis in the New Zealand Wool Research Institute, until now.

[0052] The present invention is based on industrially coating and masking nylon 610 (Hexamethylene Diamine / Sebacoyl Dichloride) uniformly on the surface of wool fibers. Therefore, washability is imparted, and further, while protecting the inside of the wool fibers, in order to increase whiteness, a basic oxidation / reduction treatment, particularly hydrogen peroxide / hydrosulfide, is selected and used in combination with an ultraviolet absorber treatment, thereby being modified into whiter and brighter wool "Whiter, Brighter Wools". Furthermore, by using low-temperature dyeing at about 85°C in combination, clear dyeing becomes possible.

Claims

1. A method for preventing yellowing and achieving vivid dyeing of wool fibers with improved washing resistance, characterized by coating bleached wool fibers with a synthetic polymer and impregnating the synthetic polymer with an ultraviolet absorber by immersing the wool fibers in an aqueous solution in which the ultraviolet absorber is dissolved.

2. The coating of the synthetic polymer is characterized in that nylon 610 is coated by polymerizing hexamethylenediamine and sebacic acid dichloride on the surface of the wool fibers by an interfacial polymerization method. The treatment method according to Claim 1.

3. The ultraviolet absorber for impregnation treatment is a benzophenone-based ultraviolet absorber or a benzotriazole-based ultraviolet absorber. The treatment method according to Claim 1 or 2.

4. The bleaching treatment is a hydrogen peroxide / hydrosulfite bleaching treatment. The treatment method according to any one of Claims 1 to 3.

5. A treatment method characterized by subjecting the wool fibers treated by the treatment method according to any one of Claims 1 to 4 to a low-temperature dyeing treatment at a dyeing temperature of 85°C ± 5°C.

6. The wool fibers are natural keratin fibers composed of one or more of wool, cashmere, mohair, angora, and camel. The treatment method according to any one of Claims 1 to 5.

7. The wool fibers are any fiber population of woven fabric, knitted fabric, non-woven fabric, sliver, and twisted yarn, which are composed of the natural keratin fibers according to Claim 6, or blended fibers or plied yarns of the natural keratin fibers and one or more synthetic fibers of nylon fiber, acrylic fiber, and polyester fiber. The treatment method according to any one of Claims 1 to 5.

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