Modified cellulose fibers, spun yarn made therefrom, and method for modifying cellulose fibers

Abstract

The present invention provides cellulose fibers and spun yarns made therefrom, which do not have a significant adverse impact on the environment like fluorine-based water repellents, have excellent spinnability, possess hydrophobicity at the same level as synthetic fibers, and whose hydrophobicity is not easily reduced by scouring and bleaching treatments, as well as a method for modifying cellulose fibers. [Solution] Modified cellulose fiber characterized in that a resin film containing at least a modified silicone resin and a formaldehyde-melamine condensate is fixed to the fiber surface, and the fiber is crosslinked with the formaldehyde-melamine condensate.

Description

Technical Field

[0001] The present invention relates to a modified cellulose fiber, a spun yarn made therefrom, and a method for modifying cellulose fibers.

Background Art

[0002] Generally, cellulose fibers are superior in hygroscopicity and water absorption compared to synthetic fibers, and when wet with water, the fibers absorb water and strongly swell, thus having a high water retention capacity. However, a drawback is that drying is extremely slow when sweating profusely or when washed by water. This is because clothes that absorb water or sweat become very heavy, and due to the slow drying, there is a problem that cold sweats are likely to occur. In order to solve such problems, there has been a demand for cellulose fibers having hydrophobicity at the same level as synthetic fibers while maintaining high hygroscopicity.

[0003] Therefore, a method of hydrophobizing cellulose fibers by water-repellent treatment with cotton or spun yarn has been proposed. For example, Patent Document 1 discloses a fiber aggregate containing cellulose water-repellent fibers treated with a fluorine-based water-repellent agent and a fiber product formed from a fiber aggregate that has not been water-repellent treated. Fluorine-based water-repellent agents are characterized in that they have a lower surface tension compared to other water-repellent agents, can impart high water repellency to fibers, and also have good durability. However, monomers having a fluoroalkyl group have become a concern for environmental impact, so fiber processing containing fluorine-based compounds has come to be shunned. In addition, when a fluorine-based water-repellent agent is processed into raw cotton of cotton fibers, the spinning property greatly decreases, resulting in poor yield and difficulty in producing high-quality spun yarns. In this specification, in order to distinguish cotton (cotton) from cotton (cotton wool), cotton (cotton wool) is simply written in katakana as "COTTON WOOL".

[0004] Furthermore, in cotton spinning, for example, the presence of cotton wax, the natural twist of the fibers, and the hygroscopic properties of the fibers are generally suitable for spinning, so spinning can be done without using spinning oils. However, when cotton is given a functional treatment, the cotton wax is removed, and the cotton is also treated with a fluorine water-repellent coating. This makes the fibers feel slimy, causing them to stick together easily and to get tangled in the rollers of the spinning machine. In addition, the fiber surface becomes more prone to static electricity, resulting in extremely poor spinability, and even with the use of spinning oils, the spinnability remains low. Therefore, even if the proportion of processed cotton in the spun yarn is reduced and the amount of oil is optimized, it is often difficult to spin the yarn at all, the quality of the spun yarn tends to be poor, and the yield drops drastically, making mass production difficult.

[0005] For this reason, there is a need for non-fluorinated water repellents that exhibit high-performance water-repellent properties as an alternative to fluorinated water repellents, and various methods for using non-fluorinated water repellents have been proposed. For example, Patent Document 2 proposes a modified fiber obtained by modifying a fiber material containing at least one of cellulose fibers or animal fibers, characterized in that a film of silicone elastomer mainly composed of C12-C15 polyoxyethylene alkyl ether and having a siloxane skeleton is fixed to at least a part of the surface, and the surface tension of the surface is 30-70 mN / m for synthetic fibers. In this modified fiber, the majority of the functional groups in the natural fiber exist in a state that has not reacted with the silicone elastomer film, and because the hydrophilic groups in the functional groups can attract water molecules, it exhibits good hygroscopicity. However, this modified fiber had the problem that it could not suppress swelling of the fiber when wet, making the clothing heavy, and that it took a very long time to dry because the fiber surface was covered with elastomer.

[0006] On the other hand, silicone resins have a problem where the siloxane main chain is easily broken by alkali, and even if cross-linking is performed, the siloxane bonds break during subsequent scouring and bleaching processes, resulting in a significant decrease in hydrophobicity. In addition, water-repellent treated cellulose fibers have a problem where the hydrophobicity is significantly reduced if the water-repellent film on the surface is damaged, as the fibers absorb water into the interior.

[0007] Furthermore, Patent Documents 3 and 4 propose a method to improve the quick-drying properties of cellulose fibers such as cotton and rayon by performing a cross-linking treatment called resin processing on them, without causing the cotton to swell. However, such resin processing significantly degrades the strength of the fibers and makes them stiff. Therefore, when applied to raw cotton, it reduces spinnability, and the quality and strength of the resulting spun yarn are poor. In practice, this process is carried out after the fabric has been woven or knitted. In addition, cellulose fibers are slightly colored compared to synthetic fibers, and natural cellulose fibers such as cotton and linen are particularly strongly colored, requiring scouring and bleaching to whiten them. However, there have been no non-fluorine hydrophobic fibers that can withstand the scouring and bleaching processes applied in the later stages. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2018-197406 [Patent Document 2] WO2015 / 083227 [Patent Document 3] Japanese Patent Publication No. 61-207672 [Patent Document 4] Japanese Patent Publication No. 2022-176436 [Overview of the project] [Problems that the invention aims to solve]

[0009] This invention was conceived in view of the current state of the prior art described above, and aims to provide cellulose fibers and spun yarns made therefrom that do not have a significant adverse impact on the environment like fluorine-based water repellents, have excellent spinnability, possess hydrophobicity at the same level as synthetic fibers, and whose hydrophobicity does not decrease easily even after scouring and bleaching treatments, as well as a method for modifying cellulose fibers. [Means for solving the problem]

[0010] As a result of diligent research to achieve the above objective, the inventors of the present invention discovered that cellulose fibers can be modified to satisfy the above objective by covering the surface of fibers or spun yarn with a resin film containing a modified silicone resin and a formaldehyde-melamine condensate, and crosslinking the fibers with a formaldehyde-melamine compound, thus completing the present invention.

[0011] In other words, the present invention has the following configurations (1) to (9). (1) Modified cellulose fiber characterized in that a resin film containing at least a modified silicone resin and a formaldehyde-melamine condensate is fixed to the fiber surface, and the fiber is crosslinked with the formaldehyde-melamine condensate. (2) The modified cellulose fiber according to (1), characterized in that the surface tension of the processed fiber is 24 to 50 mN / m. (3) The modified cellulose fiber according to (1), characterized in that the modified silicone resin is an amino-modified silicone oil having a functional group equivalent of 300 to 11000 g / mol of silicone resin. (4) The modified cellulose fiber according to (1), characterized in that the fiber is crosslinked with an initial formaldehyde-melamine condensate. (5) Modified cellulose fiber according to any one of (1) to (4), characterized in that the fiber is cotton or hemp. (6) A spun yarn made of cellulose fibers, characterized in that a resin film containing at least a modified silicone resin and a formaldehyde-melamine condensate is fixed to the surface of the spun yarn, and the fibers are crosslinked with the formaldehyde-melamine condensate. (7) A method for modifying cellulose fibers, characterized in that the cellulose fibers are immersed in an aqueous dispersion obtained by dispersing and / or dissolving a modified silicone resin and a formaldehyde-melamine initial condensate in water, and then subjected to moist heat treatment to fix the modified silicone resin and the formaldehyde-melamine initial condensate to the surface of the cellulose fibers, and the cellulose is crosslinked with the formaldehyde-melamine initial condensate inside the cellulose fibers. (8) The method according to (7), characterized in that the moist heat treatment is a moist heat treatment of 100°C or higher using superheated steam. (9) The method according to (7) or (8), characterized in that the weight ratio of the modified aminosilicone resin to the initial formaldehyde-melamine condensate in the aqueous dispersion is 95:5 to 70:30. [Effects of the Invention]

[0012] The modified cellulose fibers and spun yarns of the present invention exhibit minimal reduction in fiber strength and spinnability due to modification, and can withstand scouring and bleaching after weaving or knitting. Therefore, they can impart the same level of hydrophobicity as synthetic fibers to garments made primarily from natural fibers. Textile products using the modified cellulose fibers of the present invention retain the hygroscopic properties of cellulose while suppressing the weight gain of clothing due to sweat and moisture absorption, resulting in high quick-drying properties and reduced risk of chills from sweat. [Modes for carrying out the invention]

[0013] The modified cellulose fiber of the present invention has a resin coating containing at least a modified silicone resin and a formaldehyde-melamine condensate fixed to the fiber surface, and the fiber is crosslinked with a formaldehyde-melamine compound. Although this modified cellulose fiber is a cellulose fiber, it has a hydrophobic surface tension equal to or greater than that of synthetic fibers, and because the inside of the fiber is crosslinked, swelling when water penetrates through the gaps in the surface resin coating can be suppressed, thereby limiting the water retention capacity and preventing a decrease in surface tension.

[0014] Typical examples of cellulose fibers in the present invention include cotton, a natural plant fiber. Other examples include hemp fibers such as ramie, linen, cannabis, jute, Manila hemp, and sisal. Furthermore, the cellulose fiber may be a so-called regenerated fiber obtained by dissolving natural cellulose in a predetermined solvent and then forming it into fibers. Specific examples of this type of regenerated fiber include rayon, polynosic, cupro, and lyocell (registered trademark) (Lensing's solvent-spun fiber).

[0015] The form of the cellulose fiber is not particularly limited and may be, for example, cotton, tow, sliver, or spun yarn. However, it is preferable to perform the modification process before the individual fibers become tightly adhered and constrained spun yarn. Since the individual fibers are not constrained, a resin film containing a modified silicone resin and a formaldehyde-melamine condensate can be firmly adhered to the surface of each cellulose fiber without spots, providing modified fibers with high durability. The modification process can be carried out by attaching a treatment agent containing at least a modified silicone resin and a formaldehyde-melamine condensate to cotton (cotton), fiber bundles, yarns, etc. by methods such as impregnation, spraying, padding, etc., and then heating and curing after drying. In the present invention, the modification process may be performed after cotton dyeing or yarn dyeing.

[0016] The surface tension of the fiber can be determined, for example, by the so-called Dupont method. The Dupont method evaluates the surface tension of the fiber based on whether the droplets of a mixed reagent with the surface tension varied in 12 steps wet the fiber surface or are held in the droplet state. That is, when the surfaces of a solid and a liquid come into contact, if the surface tension of the liquid is greater than that of the solid, the liquid does not wet the solid surface and keeps the droplet. This mixed reagent is classified into 12 grades from the 1st grade to the 12th grade, and the surface tension of each grade liquid is shown in Table 1. The surface tension of the modified cellulose fiber of the present invention can be in the range of 24 to 50 mN / m when evaluated by this method. Incidentally, it is known that the surface tension of general synthetic fibers is about 60 mN / m for 6,6-nylon and about 45 mN / m for polyester. Also, the surface tension of natural fibers is known to be about 230 mN / m for cotton and about 68 mN / m for linen.

Table 1

[0017] Cellulose fibers swell significantly and become heavy when wet with water. According to the measurement method described later, the water retention rate of unmodified cotton is as high as 70%. Therefore, for example, cellulose fibers such as cotton have a significantly higher surface tension than water, so they absorb a large amount of water and swell during washing, which is the reason why drying is significantly slower compared to synthetic fibers. However, the modified cellulose fibers of the present invention suppress swelling and can reduce the water retention rate to 15% or less. Also, the water retention rate can be made 40% or less even after scouring and bleaching. On the other hand, cellulose fibers have the advantage of easily maintaining a comfortable humidity inside clothes because of their high moisture absorption rate. The official moisture regain rate is 7% for cotton, 12% for rayon, and 12% for bast fibers. However, although a slight decrease in the moisture regain rate is observed in the modified cellulose fibers of the present invention, they still maintain a high moisture regain rate compared to other fibers. In the modified cellulose of the present invention, cotton can retain a moisture regain rate of 4% or more, and bast fibers and rayon can retain a moisture regain rate of 8% or more.

[0018] Normally, silicone is easily broken in the siloxane main chain by alkali, and even if cross-linking treatment is performed, it is very weak against scouring and bleaching treatment, and its hydrophobicity is greatly reduced. And if even a part of the film on the fiber surface is damaged, water is absorbed from there, so the apparent surface tension is greatly reduced. However, the modified cellulose fibers of the present invention have high durability against peroxide bleaching by fixing a resin film containing a modified silicone resin and a formaldehyde-melamine condensate on the surface. If the surface tension of the fiber surface is adjusted to 24 - 50 mN / m in cotton processing, it becomes possible to adjust the surface tension of cellulose fibers to 40 - 59 mN / m of synthetic fibers in the state of finishing the fiber product.

[0019] The modified silicone resin used in this invention controls the surface tension of the cellulose fiber surface and imparts excellent smoothness and flexibility to the fiber, significantly improving its passability through the spinning process from blending to spinning. Due to its high molecular weight and high hydrophobicity, the modified silicone resin does not penetrate into the interior of the cellulose fiber. However, it adsorbs onto the fiber surface along with formaldehyde-melamine condensate, cross-linking and forming a film on the fiber surface, thereby improving the frictional properties of the cellulose fiber with good durability.

[0020] Examples of modified silicone resins used in this invention include silicone resin and silicone oil, but silicone oil is preferred for the purpose of uniformly adsorbing onto the entire fiber surface as an aqueous dispersion. Silicone oil is a linear organopolysiloxane. Modified silicone is an organopolysiloxane having an organic group in at least one of its side chains and terminals. From the viewpoint of adsorption to fibers, flexibility improvement effect, hydrophobicity, and reactivity, an amino-modified silicone oil is preferred.

[0021] Amino-modified silicone oils include compounds having an organic group containing an amino group and / or an imino group in at least one of the side chains and / or terminals of an organopolysiloxane. Examples of such organic groups include organic groups represented as -R-NH2 and organic groups represented as -R-NH-R'-NH2. Examples of R and R' in the organic group include divalent groups such as ethylene and propylene. The amino group and / or imino group may be partially or entirely chelated. Chelated amino group and / or imino group can be obtained, for example, by treating the amino group and / or imino group with a chelating agent. Examples of chelating agents include fatty acids having 2 to 22 carbon atoms, acid anhydrides of fatty acids having 2 to 22 carbon atoms, acid halides of fatty acids having 2 to 22 carbon atoms, and aliphatic monoisocyanates having 1 to 22 carbon atoms.

[0022] From the viewpoint of the required surface tension of the fibers, the functional group equivalent of the amino-modified silicone oil is preferably 100 to 20,000 g / mol, more preferably 200 to 15,000 g / mol, more preferably 300 to 11,000 g / mol, and even more preferably 300 to 9,500 g / mol. If the functional group equivalent is less than 100 g / mol, the hydrophilicity of the amino-modified silicone oil becomes too high, and the surface tension of the processed fibers tends to be higher than the desired range. Also, if the functional group equivalent is higher than 20,000 g / mol, the resin film after processing tends to detach easily from the fibers, and the surface tension after scouring and bleaching is low and difficult to maintain.

[0023] The theoretical amount of modified silicone resin attached to the fibers is preferably adjusted to a purity concentration of 0.1%owf (percentage of the weight of attached silicone resin relative to the weight of the fiber) to 50%owf. More preferably, it is 0.5 to 25%owf. Even more preferably, it is 1 to 15%owf. If it is lower than 0.1%owf, it may be difficult to bring the surface tension of the fibers to a level equal to or higher than that of synthetic fibers. If it exceeds 50%owf, spinnability tends to deteriorate. By keeping the amount of modified silicone resin attached to the fibers within this range, the surface tension of the fiber surface can be controlled to an appropriate range, and the excellent smoothness makes it much easier to pass through the spinning process from blending to spinning.

[0024] When using amino-modified silicone oil as a modified silicone resin, other types of silicone oil may be used in combination as needed. For example, straight silicone oils such as dimethyl silicone oil, methylphenyl silicone oil, and methyl hydrogen silicone oil; modified silicone oils such as amino-modified silicone oil, epoxy-modified silicone oil, carbinol-modified silicone oil, mercapto-modified silicone oil, carboxyl-modified silicone oil, polyether-modified silicone oil, alkyl-modified silicone oil, aralkyl-modified silicone oil, alkylaralkyl-modified silicone oil, higher fatty acid ester-modified silicone oil, and higher aliphatic amide-modified silicone oil can be used in combination.

[0025] Since modified silicone resins are poorly soluble in water, it is preferable to use a surfactant to disperse them. Suitable surfactants include, for example, nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants, with nonionic surfactants being preferred. These can be used individually or in appropriate combinations of two or more.

[0026] Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyethylene glycol fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, glycerin fatty acid esters, polyoxyethylene glycerin fatty acid esters, polyglycerin fatty acid esters, propylene glycol fatty acid esters, polyoxyethylene castor oil, polyoxyethylene hydrogenated castor oil, polyoxyethylene hydrogenated castor oil fatty acid esters, polyoxyethylene alkylamines, polyoxyethylene fatty acid amides, polyoxyethylene-modified organopolysiloxanes, and polyoxyethylene polyoxypropylene-modified organopolysiloxanes. Preferably, polyoxyethylene alkyl ethers and polyoxyethylene sorbitan fatty acid esters can be used.

[0027] From the viewpoint of emulsion stability, when using nonionic surfactants, the HLB value (or the HLB value of the entire mixture if multiple surfactants are used) is preferably in the range of 8.0 to 20.0, more preferably 11.0 to 17.0, and even more preferably 12.0 to 16.0. Suitable commercially available nonionic surfactants include Kao's "Emulgen" series, for example, Emulgen 109P (HLB 13.6) can be used. Note that the HLB value is calculated using the Griffin method. When using two surfactants with different HLB values, the HLB value is calculated using the following formula. N = N1 × W1 + N2 × W2 N: HLB value when using two types of surfactants with different HLB values N1, N2: HLB values ​​of each surfactant W1, W2: Mass fractions of each surfactant (W1 + W2 = 1)

[0028] As described above, amino-modified silicone oils stably dispersed with surfactants are available commercially. Examples of commercially available products include KF8005 (functional group equivalent: 11000), KF-868 (8800), KF-864 (3800), and KF-393 (350) from Shin-Etsu Chemical Co., Ltd., and SF-8417 (1200) and BY16-892 (1400) from Dow Toray Industries, Inc. In addition, reactive silicone oils other than amino-modified silicone oils can be used in combination with amino-modified silicones. Examples of silicone oils that can be used in combination include KF-101 (epoxy-modified silicone oil) and X-22-3701E (4000) (carboxyl-modified silicone oil) from Shin-Etsu Chemical Co., Ltd., and SF8428 (carbinol-modified silicone oil) from Dow Toray Industries, Inc. Furthermore, if you wish to further enhance hydrophobicity, you may use a methyl hydrogen silicone oil such as KF-9901 manufactured by Shin-Etsu Chemical Co., Ltd. in combination.

[0029] The formaldehyde-melamine condensate used in this invention can penetrate not only the fiber surface but also the micelles (pore portions) inside the fiber by impregnation. This allows it to condense on the fiber surface and form a film together with the silicone resin, while also crosslinking cellulose molecules within the fiber. By polycondensing while mixed with the modified silicone resin on the fiber surface, it can bond with the amino groups of the modified silicone resin or with the cellulose molecular chains, allowing the modified silicone resin to be firmly fixed to the fiber surface. The formaldehyde-melamine condensate is fixed to the fiber surface by forming a film together with the silicone resin after the initial formaldehyde-melamine condensate is applied to the cellulose fiber and then subjected to polycondensation treatment such as heat treatment.

[0030] The formaldehyde-melamine initial condensate contains any dimer or more polymers of the methylolmelamine compound. Initial condensates of dimers or more have high affinity for cellulose and easily reach micelles within the fibers, thus efficiently promoting cellulose crosslinking. It is also acceptable for monomers of methylolmelamine to be mixed with the formaldehyde-melamine initial condensate. As methylolmelamine, compounds having a melamine skeleton can be used, such as polymethylolmelamines like trimethylolmelamine and hexamethylolmelamine; alkoxymethylmelamine, in which some or all of the methylol groups of polymethylolmelamine are replaced with alkoxymethyl groups having an alkyl group with 1 to 6 carbon atoms; and acyloxymethylmelamine, in which some or all of the methylol groups of polymethylolmelamine are replaced with acyloxymethyl groups having an acyl group with 2 to 6 carbon atoms. Mixtures of these methylolmelamines may also be used. Furthermore, compounds in which urea or the like is co-condensed with part of the melamine can also be used.

[0031] The theoretical amount of formaldehyde-melamine initial condensate adhering to the fibers is preferably adjusted to a purity concentration of 0.05%owf (percentage of the weight of adhering formaldehyde-melamine initial condensate relative to the fiber weight) to 10%owf. More preferably, it is 0.1 to 5%owf. Even more preferably, it is 0.5 to 2.5%owf. If it is lower than 0.05%owf, the durability of the fiber surface film against acids, alkalis, oxidizing agents, etc. tends to decrease. If it exceeds 10%owf, the fiber strength tends to decrease significantly, and spinnability tends to deteriorate. By keeping the amount of formaldehyde-melamine initial condensate adhering to the fibers within this range, the hydrophobic film covering the fiber surface is more likely to be given durability to withstand subsequent scouring and bleaching processes. As the initial formaldehyde-melamine condensate, commercially available products such as Amidia APM, M-3, and J-101 from DIC, UNIKA RESIN380-K from Union Chemical Industry, and MM-850 from Miki Riken Kogyo Co., Ltd. can be used.

[0032] In the modification method of the present invention, it is preferable to use a catalyst from the viewpoint of promoting condensation reactions and crosslinking reactions. Such catalysts are not particularly limited, but examples include organic amine salts such as C1-C5 alkanolamine hydrochlorides such as 2-amino-2-methyl-1-propanol hydrochloride and (mono, di, tri)ethanolamine hydrochloride; borofluoride compounds such as ammonium borofluoride and borofluorite; metal salt catalysts such as magnesium chloride and magnesium sulfate; and inorganic acids such as phosphoric acid, hydrochloric acid, and boric acid. Examples of commercially available catalysts include Catalyst ACX (organic amine salt), Catalyst 376 (organic amine salt), Catalyst O (organic amine salt), Catalyst M (metal salt), Catalyst G (metal salt), and Catalyst X-110 (metal salt) from DIC Corporation; Unica Catalyst AC-30 (organic amine salt) and Unica Catalyst MC-109 (metal salt) from Union Chemical Industry Co., Ltd.; and Riken Fixer RC (organic amine salt) and Riken Fixer MX series (metal salt) from Miki Riken Kogyo Co., Ltd. These catalysts can also be used in combination with organic acids such as citric acid, tartaric acid, malic acid, maleic acid, and lactic acid as co-catalysts, as needed.

[0033] In this invention, the amount of formaldehyde-melamine condensate used in the formulation solution for cellulose fibers relative to the modified silicone resin is preferably 1 to 50% by weight, more preferably 2 to 30% by weight, and even more preferably 3 to 20% by weight. By using formaldehyde-melamine condensate in this range relative to the modified silicone resin, it is easy to obtain appropriate surface tension and scouring / bleaching durability. If the amount of formaldehyde-melamine condensate used is greater than 50% by weight, the durability against scouring and bleaching improves, but the fiber strength tends to decrease. Also, if the amount of formaldehyde-melamine condensate used is less than 1% by weight, the durability against scouring and bleaching tends to decrease.

[0034] In terms of hydrophobic durability, it is preferable to include a crosslinking agent in addition to the modified silicone resin and formaldehyde-melamine condensate in the formulation. In this case, the content of the crosslinking agent in the formulation is preferably 0.1 to 100% by weight, more preferably 0.5 to 50% by weight, and even more preferably 1 to 30% by weight, relative to the modified silicone resin, from the viewpoint of water repellency and texture. Below 0.1% by weight, the effect is small, and above 100% by weight, the stability of the formulation tends to decrease, leading to a reduced pot life and increased susceptibility to staining.

[0035] It is also preferable to use a combination of various crosslinking agents, including isocyanate-based crosslinking agents, glyoxal-based resin crosslinking agents, oxazoline-based agents, and carbodiimide-based agents. However, attention must be paid to the stability of these crosslinking agents in the formulation solution. If scum is generated during processing with the formulation solution, fiber contamination may occur or spinnability may decrease. Preferably, isocyanate or glyoxal-based resin processing agents can be used.

[0036] As an isocyanate-based crosslinking agent, a polyfunctional isocyanate compound having two or more isocyanate groups or blocked isocyanate groups is preferred. Examples of polyfunctional isocyanate compounds include diisocyanate compounds such as alkylene diisocyanates, aryl diisocyanates, and cycloalkyl diisocyanates, and modified polyisocyanate compounds such as dimers or trimers of these diisocyanate compounds. The alkylene diisocyanate preferably has 1 to 12 carbon atoms. Examples of diisocyanate compounds include tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), decamethylene diisocyanate, dodecamethylene diisocyanate, 2,4 or 2,6-tolylene diisocyanate (TDI), ethylene diisocyanate, propylene diisocyanate, 4,4-diphenylmethane diisocyanate (MDI), p-phenylene diisocyanate, and 2,4,4-trimethylhexamethylene-1,6-di Examples of isocyanates include phenylenediisocyanate, triylene or naphthylene diisocyanate, 4,4'-methylene-bis(phenylisocyanate), 2,4'-methylene-bis(phenylisocyanate), 3,4'-methylene-bis(phenylisocyanate), 4,4'-ethylene-bis(phenylisocyanate), 1-methyl-2,4-diisocyanate cyclohexane, and 4,4'-methylene-bis(cyclohexyl isocyanate). Examples of triisocyanate compounds include triphenylmethane triisocyanate and dimethyltriphenylmethane tetraisocyanate. Among the above, HDI and MDI are preferred in terms of low yellowing and film durability.

[0037] Modified polyisocyanate compounds derived from diisocyanate compounds are not particularly limited as long as they have two or more isocyanate groups. Examples include polyisocyanates having biuret structures, isocyanurate structures, urethane structures, uretdione structures, allophanate structures, trimer structures, etc., and adducts of aliphatic isocyanates of trimethylolpropane. Polymeric MDI (MDI = diphenylmethane diisocyanate) can also be used as a polyfunctional isocyanate compound. Polyfunctional isocyanate compounds can be used individually or in combination of two or more. Furthermore, the isocyanate groups of the polyfunctional isocyanate compound may be as they are, or they may be blocked isocyanate groups blocked by a blocking agent.

[0038] Examples of glyoxal resin crosslinking agents include 1,3-dimethylglyoxal urea-based resins, dimethylol dihydroxyethylene urea-based resins, and dimethylol dihydroxypropylene urea-based resins. The functional groups of these resins may be substituted with other functional groups. Examples of such glyoxal resins include Bekkamin N-80, Bekkamin LF-K, Bekkamin NS-19, and Bekkamin NS-210L manufactured by DIC Corporation, and UNI RESIN GS-20E (glyoxal content 60 ppm or less) GS-25 manufactured by Miki Riken Kogyo Co., Ltd.

[0039] The modified cellulose fibers of the present invention can be obtained by applying a formulation solution to cellulose fibers through processing methods such as impregnation, spraying, and padding. Specific processing equipment includes Obermeyer dyeing machines, loose dyeing machines, cheese dyeing machines, sliver continuous processing machines, and spraying devices. Among these, immersion-type dyeing machines such as Obermeyer dyeing machines and cheese dyeing machines are preferred because they allow cross-linking to penetrate more easily into the interior of the fibers compared to spraying and continuous dyeing methods.

[0040] The formulation solution is prepared as an aqueous dispersion by dispersing and / or dissolving components such as modified silicone resin, formaldehyde-melamine condensate, a crosslinking agent if necessary, and other auxiliary agents in water. The amount of modified silicone resin and formaldehyde-melamine condensate each adhering to the fiber in this aqueous dispersion should be appropriately adjusted according to the material, form, shape, and dimensions of the fiber material so that the surface tension of the modified cellulose fiber after processing is 24 to 50 mN / m. Assuming that the weight of the formulation solution adhering to the fiber is 100% of the weight of the cotton after immersion and processing in the formulation solution and dewatering, the concentration of the aqueous dispersion can be adjusted by, for example, using 0.5 to 20% sol. of modified silicone resin particles and 0.1 to 5% sol. of formaldehyde resin on a pure content basis to adjust the amount of each component of the formulation solution adhering to the fiber. If a crosslinking agent is added, 0.01 to 5% sol. of the crosslinking agent should be used. The amount of formulation solution held by the cotton after dewatering varies depending on the processing equipment used, so the actual amount of formulation solution held should be checked and the formulation solution concentration should be adjusted by proportional calculation. After immersing the cellulose fiber cotton in the aqueous dispersion prepared as described above, it is dewatered by a method such as centrifugal dewatering. The amount of treatment solution adhering after dewatering is preferably 50-300% of the cotton weight before processing. Preferably, the dewatering time and other factors are adjusted so that it is 100-200% by weight. After that, drying is performed by a standard method, and the cotton is heat-treated to make the fibers hydrophobic with good durability. This heat treatment crosslinks the silicone particles with each other and the silicone with the cellulose molecular chains, and condenses the formaldehyde resin, which is a monomer and / or a polymer of two or more monomers, into a polymer. As a result, the modified silicone resin and the formaldehyde-melamine condensate form a thin film on the fiber surface, and this film adheres to the cellulose fiber surface mainly by the anchoring effect. As a result, modified cellulose fibers with the desired surface tension are obtained.

[0041] The aforementioned heat treatment can be carried out by dry heat and / or moist heat treatment, but moist heat treatment is preferred. Moist heat treatment can uniformly heat the inside of fiber aggregates such as cotton, does not easily degrade the fiber properties, and the formaldehyde generated by the heating can be easily removed. Moist heat treatment is preferably carried out by steam setting using water vapor. For example, by heat treatment using superheated steam of 100°C or higher, the formaldehyde-melamine initial condensate on the fiber surface can be polymerized on the fiber to form a film, or crosslinked with cellulose fibers inside the fiber. In addition, the modified silicone resin, formaldehyde-melamine condensate, and cellulose fibers can be crosslinked with each other, making it possible to obtain a highly durable modified fiber. Furthermore, by filling the atmosphere around the cellulose fibers with steam through steam heat treatment, the generation of reactive oxygen species can be suppressed. This makes it possible to obtain a modified fiber in which embrittlement and yellowing of the cellulose fibers are well avoided. This heat treatment should be carried out at 100°C or higher for 1 to 60 minutes. Preferably, the treatment should be performed at 110°C to 135°C, and more preferably at 120°C to 130°C. Yellowing is more likely to occur above 135°C. When performing dry heat treatment, existing heating equipment such as a hot air dryer can be used. Dry heat treatment should be performed at 120°C to 170°C for 10 to 120 minutes. Preferably, it should be 130°C to 160°C. Yellowing and fiber deterioration are more likely to occur above 170°C.

[0042] As described above, the modified cellulose fibers obtained are firmly bonded to the surface of the cellulose fibers due to the presence of modified silicone resin together with formaldehyde-melamine condensate. This is achieved through the anchoring effect of the strong film formed by the formaldehyde-melamine condensate. In other words, because the silicone film is firmly bonded to the fiber surface, the fibers exhibit excellent flexibility and smoothness, resulting in improved spinability. Furthermore, the film is less likely to detach even when the fibers come into contact with each other or with the spinning machine during the spinning process. In addition, the modified cellulose fibers of the present invention have improved smoothness and maintain flexibility even when crosslinked, resulting in good spinability. The strength of the resulting spun yarn does not easily decrease, and the yarn quality is relatively good. The strength retention rate compared to spun yarn from unprocessed cotton is maintained at 75% or higher, and can even be maintained at 80% or higher.

[0043] The modified cellulose fibers of the present invention can be suitably used in clothing, bedding, interior furnishings, industrial materials, and the like. Because the hydrophobic cellulose fibers of the present invention are hydrophobic and do not swell strongly, they have excellent quick-drying properties and are resistant to mold growth, making them suitable for use as padding in bedding and interior furnishings. Furthermore, woven or knitted fabrics using at least a portion of the modified cellulose fibers of the present invention dry easily when sweating and are less prone to causing chills from sweat, thus providing suitable fabrics for innerwear, outdoor clothing, sportswear, casual clothing, and the like. [Examples]

[0044] The effects of the present invention will be demonstrated below with reference to examples, but the present invention is not limited to these examples. The method for evaluating the characteristic values ​​in the examples is as follows.

[0045] <Surface tension of the fiber surface> The surface tension of a fiber is determined by the so-called Dupont method. Specifically, first, 12 different mixed reagents of varying concentrations are prepared by mixing isopropyl alcohol (IPA) and distilled water. These 12 mixed reagents are classified into 12 grades, from grade 1 to grade 12, according to their mixing ratio, and Table 1 shows each grade and its surface tension. Next, the mixed solution is gently dropped drop by drop from 1 cm above the sample using a burette. Five droplets are dropped onto the sample from different locations and left to stand for 10 seconds. The grade number of the mixed reagent that retains two or more droplets is then determined. The surface tension of the mixed reagent with the highest grade number is evaluated as the surface tension of the sample to be measured. Note that a sample that retains droplets of 100% deionized water (without IPA), even if it is below grade 1, is judged to have a surface tension of 72 mN / m. If the sample is dropped without retaining droplets of 100% deionized water, it is judged to have a surface tension of 73 mN / m or higher. Using the method described above, the surface tension of the cotton (spun yarn in Example 6) in the Examples and Comparative Examples was measured, as well as the surface tension of each processed cotton after further scouring and bleaching treatment with Formulation 1 described later.

[0046] <Moisture retention rate after water absorption and dehydration> The moisture retention rate after water absorption and dewatering is used to evaluate the swelling ability of the fibers in relation to water. For each of the modified cotton in the examples and comparative examples, 10.00 g (referred to as the "weight before treatment") of cotton, which was first dried at 105°C for 2 hours and then humidified under standard conditions for 48 hours, was placed in taffeta bags to create 10 bags. 30 L of water (water temperature: 25-29°C) was placed in a washing machine (JIS C 9606), and 0.5 g / L of nonionic surfactant (Nonionic HC, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was dispersed in the washing solution. Then, the 10 bags of cotton were placed in the water and rotated for 10 minutes under "strong conditions". After dewatering for 3 minutes, the bags were removed, and the measured weight of the cotton after dewatering was taken as the "weight after treatment". The water retention rate was measured using the following formula. Water retention rate (%) = ((Weight after treatment - Weight before treatment) / Weight before treatment) × 100 Each 10.00g of weighed cotton was placed in a bag made of polyester filament taffeta, and the four sides of the bag were sewn with polyester sewing thread to prevent fibers from leaking out during washing. After dewatering, the weight was measured, and the weight of the taffeta and sewing thread was subtracted to obtain the processed weight of the cotton. The cotton in the examples and comparative examples (spun yarn in Example 6) was further scouring and bleaching treatment with Formulation 1, and the moisture retention rate was measured in the same manner.

[0047] <Spinning properties> During the spinning of 10 kg of yarn, the evaluation was based on whether yarn breakage occurred during spinning, whether the card web was uniform, and whether foreign matter adhered to the rollers or fibers got entangled during spinning. ◎ was used to indicate a uniform card web, no entanglement on the rollers, and spinability comparable to unprocessed raw cotton; ○ indicated good spinability but some roller contamination; △ indicated an uneven card web, some roller contamination and entanglement; × indicated yarn breakage; and spinning was impossible. The evaluation was based on a five-point scale: ◎, ○, △, ×, and impossible.

[0048] <Cotton moisture content> The moisture content of the cotton was measured in accordance with JIS-L1019:2006 7.1. However, the weight before drying was measured under standard conditions of 20°C and 65% RH.

[0049] <Tensile strength of spun yarn> In accordance with the JIS method of JIS-L1095:2010 9.5.1, the test was conducted using a low-speed elongation type with a gripping distance of 25 cm and a tensile speed of approximately 100% of the gripping distance per minute, and the standard breaking load (N) was measured.

[0050] (Example 1) As cellulose fibers, 100% Supima cotton with a micronear fineness of 3.2 μg and an average fiber length of 34 mm is used, resulting in a density of 0.3 g / cm³. 3The cotton was then filled into carriers and treated with Formula 1 for scouring and bleaching at a processing temperature of 95°C for 60 minutes using an Obermeyer dyeing machine (HUHT-250 / 350 manufactured by Hisaka Seisakusho), followed by hot water and cold water rinsing. Subsequently, Formula 2 was used to treat the cotton at a processing temperature of 40°C for 20 minutes, after which the cotton was removed and the amount of formula solution attached to the cotton was adjusted by centrifugal dehydration for 2 minutes. At this time, the weight of the cotton immediately after dehydration had increased by 150% compared to before processing. The amount of formula solution attached was 150% owf. After that, it was dried and heat-treated by steam at 120°C for 30 minutes using a vacuum steam setter manufactured by Nikko Kogyo Co., Ltd. Prescription 1: Caustic soda (manufactured by Nippon Soda Co., Ltd.) 1g / L Scouring agent (Pitchlan L250, manufactured by Nikka Chemical Co., Ltd.) 1g / L Hydrogen peroxide stabilizer (PLC7000, manufactured by Nikka Chemical Co., Ltd.) 1g / L 35% hydrogen peroxide 4 ml / L Bath ratio 1:10 Prescription 2: Amino-modified silicone (Shin-Etsu Chemical Co., Ltd. KF880, side-chain type diamine-based modification, functional group equivalent 180) 10.0% owf Methylated methylolmelamine initial condensate (main component 80% aqueous solution) 1.5% owf Organic amine catalyst (35% aqueous solution) 0.5% owf Bath ratio 1:10

[0051] Subsequently, a spinning oil for cotton was applied to this processed cotton, and after blending it using 100% of this processed cotton in an OHARA blending machine, card sliver was produced using an Ishikawa Seisakusho carding machine. Only the longest fibers were kept after being passed through a combing machine, and the sliver was passed twice through a Hara Loom Machinery drawing machine to produce a 400 gelen / 6yd sliver. Further, it was passed through a Toyota Industries roving machine to produce a 140 gelen / 15yd roving. Next, this roving was subjected to a draft of approximately 28 times in a Toyota Industries spinning machine and twisted in the Z direction to produce a 25 count ring-spun yarn in English count. The twist coefficient (k) of this spun yarn was 3.8. In the evaluation of spinnability, the card web was uniform, there was no entanglement with the rollers in the spinning machine, and there was no yarn breakage, indicating good spinnability.

[0052] (Example 2) Processed cotton was prepared in the same manner as in Example 1, except that Formulation 3 was created by lowering the concentrations of the methylated methylolmelamine initial condensate and the organic amine catalyst in Formulation 2 of Example 1. Subsequently, 25-count spun yarn was prepared in the same manner as in Example 1. Prescription 3: Amino-modified silicone (KF880, manufactured by Shin-Etsu Chemical Co., Ltd.) 10.0% owf Methylated methylolmelamine initial condensate (main component 80% aqueous solution) 0.5% owf Organic amine catalyst (35% aqueous solution) 0.2% owf Bath ratio 1:10

[0053] (Example 3) Processed cotton was prepared in the same manner as in Example 1, except that the type of amino-modified silicone in Formulation 2 of Example 1 was changed to amine-modified silicone KF868 (functional group equivalent 8800, side-chain type monoamine modified) in Formulation 4. Subsequently, 25-count spun yarn was prepared in the same manner as in Example 1. Prescription 4: Amino-modified silicone (KF868, manufactured by Shin-Etsu Chemical Co., Ltd.) 10.0% owf Methylated methylolmelamine initial condensate (main component 80% aqueous solution) 1.5% owf Organic amine catalyst (35% aqueous solution) 0.5% owf Bath ratio 1:10

[0054] (Example 4) Processed cotton was prepared in the same manner as in Example 1, except that the type of amino-modified silicone in Formulation 2 of Example 1 was changed to amino-modified silicone KF393 (functional group equivalent 350, side-chain type diamine modified) in Formulation 5. Subsequently, 25-count spun yarn was prepared in the same manner as in Example 1. Prescription 5: Amino-modified silicone (KF393, manufactured by Shin-Etsu Chemical Co., Ltd.) 10.0% owf Methylated methylolmelamine initial condensate (main component 80% aqueous solution) 1.5% owf Organic amine catalyst (35% aqueous solution) 0.5% owf Bath ratio 1:10

[0055] (Example 5) Processed cotton was prepared in the same manner as in Example 1, except that Formulation 6 was created by adding blocked hexamethylene diisocyanate to Formulation 2 of Example 1. Subsequently, 25-count spun yarn was prepared in the same manner as in Example 1. Prescription 6: Amino-modified silicone (KF880, manufactured by Shin-Etsu Chemical Co., Ltd.) 10.0% owf Methylated methylolmelamine initial condensate (main component 80% aqueous solution) 1.5% owf Blocked hexamethylene diisocyanate (20% aqueous dispersion) 5.0% owf Organic amine catalyst (35% aqueous solution) 0.5% owf Bath ratio 1:10

[0056] (Example 6) As the cellulose fiber, 100% Supima cotton (unprocessed cotton) with a micronear fineness of 3.2 μg and an average fiber length of 34 mm was used. Combed sliver was prepared by blending, carding, and combing in the same manner as in Example 1, and then passed through a drawing machine twice to produce 25-count ring-spun yarn of 100% unprocessed cotton through roving and spinning processes. The twist coefficient (k) of this spun yarn was 3.8. This spun yarn was made into a soft wind using an L-type press bobbin with a Kozu Seisakusho SSP-GSSE type precision winder. Soft wind cheeses for yarn dyeing were prepared every 11 pieces and dyed using an Obermeyer dyeing machine (HUHT-250 / 350). Scouring and bleaching were performed using Formula 1 and hydrophobic treatment using Formula 2, as in Example 1. Drying was performed at 90°C using a Nissen 4LDP-R type cheese dryer. Subsequently, heat treatment was performed using a vacuum steam setter manufactured by Nikko Kogyo Co., Ltd., at 120°C for 30 minutes.

[0057] (Example 7) The ramie stalks were scuttled with a scutching roller, and the fibrous mass of the peeled pulp was passed through a roller to soften it. This fibrous mass was then immersed in a 20 g / L (pH 13.7 at 25°C) sodium hydroxide solution and boiled for 180 minutes to refine it. Finally, the fibers were opened and separated by re-fluffing to obtain fine ramie fibers. These were packed into a material with a density of 0.20 g / cm³. 3 The fibers were then filled into a carrier and treated with Formulation 2 under the same conditions as in Example 1 using an Obermeyer dyeing machine to produce hydrophobic ramie fibers. 20% by weight of these hydrophobic ramie fibers and 80% by weight of hydrophobic Supima cotton from Example 1 were blended, and then a 25-count ring-spun yarn was produced using the English count method in the same manner as in Example 1.

[0058] (Example 8) Processed cotton was prepared in the same manner as in Example 1, except that the type of amino-modified silicone in Formulation 2 of Example 1 was changed to amino-modified silicone KF873 (functional group equivalent 18000) in Formulation 7. Subsequently, 25-count spun yarn was prepared in the same manner as in Example 1. Prescription 7: Amino-modified silicone (KF873, manufactured by Shin-Etsu Chemical Co., Ltd.) 10.0% owf Methylated methylolmelamine initial condensate (main component 80% aqueous solution) 1.5% owf Organic amine catalyst (35% aqueous solution) 0.5% owf Bath ratio 1:10

[0059] (Comparative Example 1) Processed cotton was prepared in the same manner as in Example 1, except that Formulation 2 of Example 1 was changed to Formulation 8, which consists only of amino-modified silicone. Subsequently, 25-count spun yarn was prepared in the same manner as in Example 1. Prescription 8: Amino-modified silicone (KF880, manufactured by Shin-Etsu Chemical Co., Ltd.) 10.0% owf Bath ratio 1:10

[0060] (Comparative Example 2) Processed cotton was prepared in the same manner as in Example 1, except that Formulation 2 of Example 1 was changed to Formulation 9, which consisted only of a methylated methylolmelamine initial condensate and an organic amine catalyst. Subsequently, 25-count spun yarn was prepared in the same manner as in Example 1. Prescription 9: Methylated methylolmelamine initial condensate (main component 80% aqueous solution) 1.5% owf Organic amine catalyst (35% aqueous solution) 0.5% owf Bath ratio 1:10

[0061] (Comparative Example 3) Processed cotton was prepared in the same manner as in Example 1, except that the cotton was processed using formulation 10, which contains a fluorine-based water repellent that does not contain perfluoroalkyl groups with 7 or more carbon atoms. Subsequently, 25-count spun yarn was prepared in the same manner as in Example 1. Prescription 10: Asahi Guard E-060 (manufactured by Asahi Glass) 10.0% owf Blocked isocyanate (20% aqueous dispersion) 5.0% owf Bath ratio 1:10

[0062] (Comparative Example 4) Processed cotton was prepared in the same manner as in Example 1, except that formulation 11 was created by reducing the concentration of the fluorine-based water repellent in formulation 10 of Comparative Example 3 to 1 / 10. Subsequently, 25-count spun yarn was prepared in the same manner as in Example 1. Prescription 11: Asahi Guard E-060 (manufactured by Asahi Glass) 1.0% owf Blocked isocyanate (20% aqueous dispersion) 5.0% owf Bath ratio 1:10

[0063] (Comparative Example 5) Cotton was prepared by performing only the scouring and bleaching process according to Formulation 1 of Example 1, without the hydrophobic treatment according to Formulation 2, and spun yarn was produced in the same manner as in Example 1.

[0064] Table 2 shows the details and evaluation results of Examples 1-8 and Comparative Examples 1-5. [Table 2]

[0065] As shown in Table 2, the modified fibers of Examples 1 to 8 all had a surface tension in the range of 25 to 42 mN / m after modification (post-processing). Furthermore, the cotton that was subsequently scouring and bleached had a surface tension in the range of 40 to 59 mN / m, maintaining hydrophobicity equivalent to that of synthetic fibers. In other words, the modified fibers of Examples 1 to 8 showed excellent durability, with the resin coating being difficult to detach from the fiber surface even after post-processing.

[0066] In Comparative Example 1, which used only modified silicone resin, and Comparative Example 2, which used only formaldehyde-melamine initial condensate, a strong film was not formed, resulting in excessively high surface tension after scouring and bleaching. Regarding water retention, Comparative Example 1, which did not use formaldehyde-melamine initial condensate, showed a significant decrease in water retention after bleaching. This is thought to be because cross-linking bonds within the fibers were not formed, allowing water to penetrate through areas where the silicone film was damaged during scouring and bleaching, causing significant swelling. In Comparative Examples 3 and 4, which used a fluorine water repellent, the surface tension after scouring and bleaching showed high hydrophobicity exceeding that of synthetic fibers, but the spinnability was poor and it could not be made into yarn, or while it could be made into yarn at a lower concentration, the quality was reduced. Comparative Example 5, which did not undergo hydrophobic processing, showed high surface tension and high water retention. [Industrial applicability]

[0067] The modified cellulose fibers and spun yarns of the present invention exhibit minimal reduction in fiber strength and spinnability due to modification, and can withstand scouring and bleaching after weaving or knitting. Therefore, they can impart the same level of hydrophobicity as synthetic fibers to garments primarily made from natural fibers. Textile products using the modified cellulose fibers of the present invention retain the hygroscopic properties of cellulose while suppressing the weight increase caused by sweat and moisture absorption, resulting in high quick-drying properties and reduced risk of chills from sweat. Consequently, the present invention is extremely useful in the industry.

Claims

1. A modified cellulose fiber characterized in that a resin coating containing at least a modified silicone resin and a formaldehyde-melamine condensate is fixed to the fiber surface, and the fiber is crosslinked with the formaldehyde-melamine condensate.

2. The modified cellulose fiber according to claim 1, characterized in that the surface tension of the processed fiber is 24 to 50 mN / m.

3. The modified cellulose fiber according to claim 1, characterized in that the modified silicone resin is an amino-modified silicone oil having a functional group equivalent of 300 to 11,000 g / mol of silicone resin.

4. The modified cellulose fiber according to claim 1, characterized in that the fiber is crosslinked with an initial formaldehyde-melamine condensate.

5. A modified cellulose fiber according to any one of claims 1 to 4, characterized in that the fiber is cotton or hemp.

6. A spun yarn made of cellulose fibers, characterized in that a resin coating containing at least a modified silicone resin and a formaldehyde-melamine condensate is fixed to the surface of the spun yarn, and the fibers are crosslinked with the formaldehyde-melamine condensate.

7. A method for modifying cellulose fibers, characterized by immersing the cellulose fibers in an aqueous dispersion obtained by dispersing and / or dissolving a modified silicone resin and a formaldehyde-melamine initial condensate in water, and then subjecting the cellulose fibers to moist heat treatment to fix the modified silicone resin and the formaldehyde-melamine initial condensate to the surface of the cellulose fibers, and crosslinking the cellulose with the formaldehyde-melamine initial condensate inside the cellulose fibers.

8. The method according to 7, characterized in that the moist heat treatment is a moist heat treatment of 100°C or higher using superheated steam.

9. The method according to 7 or 8, characterized in that the weight ratio of the modified aminosilicone resin to the initial formaldehyde-melamine condensate in the aqueous dispersion is 95:5 to 70:30.

Images