MODIFIED FIBER, PROCESS FOR PRODUCING THE SAME, AND FIBER PRODUCT

Abstract: An object of the invention is to provide cellulose fibers which are excellent in the dirt removability and which maintain the properties without impairment when exposed to repeated laundry, a process for preparing the cellulose fibers and a product thereof. The cellulose fibers of the invention are liquid ammonia-treated cellulose fibers whose partial or entire exterior is coated with an ester of (A) a polycarboxylic acid having at least three carboxyl groups and (B) a hydrophilic polyol having an oxyethylene group or groups and at least two alcoholic hydroxyl groups and/or which fibers are impregnated with the ester.

Description: The present invention relates to cellulose fibers excellent in the property of removing dirt, and to processes for preparing the same and a product thereof. JP-A-5-247 844 discloses preparation of cellulose fibres having shrink-proof properties, by impregnation using an ester containing at least two carboxylic groups and heating. JP-A-60-246 871 discloses a polyester resin hard finishing agent for textiles of synthetic, chemical and/or natural fibres. US-A-3 980 429 discloses a continuous process for the treatment, with liquid ammonia, of moving webs of fabric. Cellulose fibers, typically cotton, are widely used for clothes and products of fibers because of their many advantages such as high hygroscopicity and good feel. Products of cellulose fibers are soiled with oil, sebum, mud or the like due to the use and wearing and are cleaned by laundry for re-use. However, such dirt is likely to cling to cellulose fibers and products thereof and can not be easily removed by laundry. Consequently, this leads to disadvantages of stain, black smear, discolored smudge, etc. which reduce the value of clothes and the like. For this reason, a need exists for products of cellulose fibers having improved dirt-removing property (dirt removability). Dirt does not easily come off by laundry from cotton and the like which readily absorb oily and aqueous substances. So far, products of cotton free from said problem have not been found. In such current situation, it has been proposed to attach polyvinyl alcohol as a laundry size to products of cellulose fibers. The proposed method contemplates causing the dirt to adhere to polyvinyl alcohol so that the dirt is separated, together with polyvinyl alcohol, from the product of cellulose fibers by laundry. However, the method can achieve this effect only once, and necessitates depositing polyvinyl alcohol on a product of cellulose fibers every time the product is washed. Thus the method can not be said to be means for improving dirt removability. On the other hand, polyester, nylon and other synthetic fibers are extensively used for their numerous advantages such as high mechanical properties, chemical resistance and ease of care, but have a drawback of tending to permit accumulation of static electricity. Various antistatic agents have been used to overcome the drawback, but substantially all of them come off during laundry and are merely temporarily effective. For practical use as clothes, products of synthetic fibers should be imparted laundry durability as well as antistatic property. As a method of giving antistatic property to a product of synthetic fibers, it is known to coat synthetic fibers with a hydrophilic polymer having double bonds by radical polymerization (Japanese Examined Patent Publication JP-B-60-40 554 (1985)). However, a fully crosslinked polymer needs to be formed to produce a coating film having the required washing resistance from a hydrophilic polymer. The radical polymerization of a hydrophilic polymer with double bonds for conversion to a crosslinked polymer entails a disadvantage of essentially using an ethyleneimine derivative, i.e. a highly toxic crosslinking agent or a volatile, highly toxic acrylic acid. Said conventional procedure makes it difficult to maintain hygiene and healthy working environment, and needs special apparatus. Therefore the procedure has not been a useful technique in an ordinary processing plant which is intended to use mainly open-type equipment. It is desirable to provide cellulose fibers which are excellent in the dirt removability and which are free from impairment of properties due to repeated laundry, and processes for preparing the cellulose fibers and a product thereof. Other features of the present invention will become apparent from the following description. According to the present invention, there are provided liquid ammonia-treated cellulose fibers which are treated, by at least one of exterior surface coating and impregnation, with an ester of (A) a polycarboxylic acid which has at least three carboxyl groups and (B) a hydrophilic polyol which has at least one oxyethylene group and at least two alcoholic hydroxyl groups such that a reaction occurs between carboxyl groups of the polycarboxylic acid and hydroxyl groups of the cellulose fibres. The invention also provides a process for producing liquid ammonia-treated cellulose fibers, which process comprises (i) treating cellulose fibers with liquid ammonia, (ii) depositing an ester of (A) a polycarboxylic acid which has at least three carboxyl groups (hereinafter referred to as "present polycarboxylic acid"), and (B) a hydrophilic polyol which has at least one oxyethylene group and at least two alcoholic hydroxyl groups (hereinafter referred to as "present polyol"), on the exterior of the liquid ammonia-treated cellulose fibers, and/or impregnating the liquid ammonia-treated cellulose fibers with a said ester, and (iii) heating the fibres to react carboxyl groups of the polycarboxylic acid and hydroxyl groups of the cellulose fibres. Alternatively, step (ii) may consist in depositing the present polycarboxylic acid and the present polyol on the exterior of the liquid ammonia-treated cellulose fibers, and/or impregnating the liquid ammonia-treated cellulose fibers with the present polycarboxylic acid and the present polyol, and the heating of step (iii) also causes esterification of the polycarboxylic acid and the hydrophilic polyol (these steps being hereinafter called "esterification treatment"). According to the invention, a product of cellulose fibers can be prepared by (1) treating the cellulose fibers with liquid ammonia, subjecting the fibers to esterification treatment and making the fibers into a product thereof by a conventional method or (2) treating the cellulose fibers with liquid ammonia, making the fibers into a product thereof by a conventional method and subjecting the product to esterification treatment. The cellulose fibers of the invention and a product thereof (defined below) are outstanding in the dirt removability and the property of maintaining the dirt removability without impairment even on exposure to repeated laundry (hereinafter called "laundry durability"). Dirt is unlikely to cling to the cellulose fibers of the present invention and products thereof. Examples of dirt are oily dirt derived from motor oil, machine oil, grease, lipstick, edible oil, shoe polish, wax, sebum (so-called dirt on the collar), and aqueous dirt derived from mud, Indian ink, carbon (pencil), foods, seasonings (soy sauce, Worcester sauce, ketchup, curry, sauce for roast meat, etc.), and beverages (green tea, coffee, etc.). Even if dirt should come to lie on the cellulose fibers of the invention, the dirt would be scarcely likely to adhere to the fibers due to the remarkable dirt removability of the fibers. According to the processes of the present invention, the desired cellulose fibers and products of cellulose fibers (defined below) can be prepared with safety and ease. Further, the present polycarboxylic acid and the present polyol to be used in the present invention are non-toxic and non-volatile and therefore are free from problems of hygiene and working environments. Discussed below are the improved cellulose fibers of the present invention, processes for preparing the same and products of cellulose fibers. The term "cellulose fibers" used herein refers to natural cellulose fibers such as cotton and hemp, regenerated cellulose fibers such as rayon, and fibers produced by mix-spinning these fibers. The cellulose fibers of the present invention include not only the foregoing fibers but those made by primary processing of these fibers such as threads, knit, textile, knitting, non-woven fabric, etc. The term "product of cellulose fibers according to the invention" used herein means products produced by further processing the foregoing cellulose fibers such as clothes, beddings, interior goods, etc., according to claims 8 or 9. In the practice of the invention, the cellulose fibers of the invention or products thereof can be mix-spun, twisted or knitted together with the cellulose-free synthetic fibers according to claim 10. Examples of cellulose-free synthetic fibers include a wide variety of those heretofore known, such as the synthetic fibers made of polyester, liquid crystal polyester, polyamide, liquid crystal polyamide, acryl, polyethylene, polypropylene, Spandex or the like. Among said synthetic fibers, those of polyester, polyamide, acryl or polypropylene are preferred and those of polyester are more preferred. In mix-spinning the cellulose fibers and said synthetic fibers, the mix-spinning ratio is not specifically limited, but the synthetic fibers may be used in a ratio of up to 80% by weight, preferably up to 70% by weight, based on the total fibers. For treating the cellulose fibers with liquid ammonia according to the invention, a wide variety of conventional methods can be used and include, for example, the method disclosed in Japanese Unexamined Patent Publication JP-A-52-152 595 (1977), corresponding to US-A-4 152 907 and US-A-4 099 911 "Why Cotton ?", Commodity Knowledge of Cotton Products (published by Japanese Cotton Industry Promotion Association, 1994), etc. For example, the liquid ammonia-treated cellulose fibers to be used in the invention can be prepared by immersing cellulose fibers in liquid ammonia to swell the fibers and removing ammonia from the swollen fibers. Swelling occurs by immersion of fibers in liquid ammonia for 0.1 to 200 seconds, preferably 5 to 30 seconds. The removal of ammonia can be done by any of dry steam method and water method. According to the dry steam method, liquid ammonia is vaporized for removal by contact of the fibers with a high speed roller in treating the fibers with liquid ammonia. In the practice of the invention, a method can be used which comprises accelerating the removal of ammonia by water vapor or a thin layer of water after contact with a high speed roller. The water method comprises removing ammonia using water as a medium after treatment with liquid ammonia. Stated more specifically, the method comprises washing the fibers with low temperature water and then with warm water and drying them by a high temperature cylinder. The cellulose fibers of the invention are subjected to esterification treatment after treatment with liquid ammonia. The esterification treatment is described below in detail. Examples of the present polycarboxylic acid for use in the invention include a wide range of conventional polycarboxylic acids which have at least 3 carboxyl groups, such as aliphatic polycarboxylic acids, alicyclic polycarboxylic acids, aromatic polycarboxylic acids, etc. These polycarboxylic acids may have a hydroxyl group, halogen group, carbonyl group and carbon-carbon double bonds. More specific examples of the present polycarboxylic acids are tribasic acids such as tricarballylic acid, aconitic acid, methylcyclohexene tricarboxylic acid and citric acid, tetrabasic acids such as butanetetracarboxylic acid, cyclopentanetetracarboxylic acid, tetrahydrofurantetracarboxylic acid and an ene adduct of methyl tetrahydrophthalate with maleic acid, trimellitic acid, pyromellitic acid, biphenyltetracarboxylic acid, benzophenonetetracarboxylic acid, diphenylsulfonetetracarboxylic acid and like aromatic polycarboxylic acids, tetracarboxylic acids prepared from styrene and maleic anhydride by Diels-Alder reaction and ene reaction, etc. These polycarboxylic acids can be used either alone or in combination. Among these polycarboxylic acids, water-soluble polycarboxylic acids such as tricarballylic acid, aconitic acid and citric acid are preferred because of high workability. Butanetetracarboxylic acid which is water-soluble tetrabasic acid can achieve the highest effect and hence is more preferred. The present polyols to be used in the invention include a wide variety of conventional polyols which have an oxyethylene group (or groups) and at least 2 alcoholic hydroxyl groups. Specific examples are polyethylene oxide polypropylene oxide adducts of ethylene oxide with compounds having at least 2 active hydrogen atoms such as amines, phenols, alcohols or the like. These polyols can be used either alone or in combination. Examples of compounds having at least 2 active hydrogen atoms which can be used in the invention are neopentyl glycol, methylpentanediol, trimethylpentanediol and like diols having 5 to 12 carbon atoms and their branched alcohols; polypropylene glycol, polymers of 1,2-butylene oxide, poly(1,4-butylene glycol) and like polyether alcohols; glycerin, diglycerin, triglycerin, polyglycerin, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol and like alcohols having at least 3 hydroxyl groups; cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, spiroglycol, geometrical isomers thereof and like alicyclic alcohols; xylitol, sorbitol, mannitol, erythritol and like reducing sugars; xylose, sorbose, arabinose, ribose, erythrose, galactose, sorbitan and like monosaccharides; lactose, sucrose, maltose and like disaccharides; hydroquinone, resorcin, catechol, bisphenol A, bisphenol S, phenol novolak, cresol novolak and like phenols; ammonia, monoalkylamine having 1 to 22 carbon atoms, alkylenediamine, alkylenetriamine, aniline, o-, m-, p-phenylenediamine, xylylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, diaminodiphenyl ether, diaminodiphenyl ketone and polycondensate of aniline and formalin. Polyethylene glycol and adducts of ethylene oxide with bisphenol A, pentaerythritol, ethylenediamine or the like are the most preferred because of their effects, workability, availability of raw materials and good feel of finished products. Polyester polyols prepared from said polyols and aliphatic dicarboxylic acid having 2 to 12 carbon atoms or aromatic dicarboxylic acid can be used as the present polyol. Among these polyester polyols, those at least soluble in a solvent, preferably in water are desirable. The polyols which can be emulsified or solubilized with a surfactant although insoluble in water can be used. The present polyol preferably has a molecular weight of 200 to 20,000. Even a polyol having a molecular weight of less than 200 can be preferably used in the present invention when mixed with a polyol more than 200 in molecular weight to give mixed polyols with an average molecular weight within said range. Even a polyol having a molecular weight of more than 20,000 can be preferably used in the present invention when mixed with a polyol less than 20,000 in molecular weight to give mixed polyols having an average molecular weight within said range. Further in the present invention, the present polyol can be used as mixed with a compound containing said active hydrogen atoms as such or as mixed with an adduct of a small number of moles of ethylene oxide with said compound having a molecular weight of less than 200. The present polyol 400 to 2,000 in molecular weight is more preferred. The ester to be deposited on and/or diffused into the liquid ammonia-treated cellulose fibers is an ester of the present polycarboxylic acid and the present polyol which has at least two carboxyl groups in one molecule. Typical examples of the structure of such polyester are as follows. (A 1 )-[(B)-(A 2 )] 1 -(B)-(A 1 ) (B)-[(A 2 )-(B)] m -(A 2 )-B (A 1 )-[(B)-(A 2 )] n -B wherein A 1 is a terminal group derived from the present polycarboxylic acid; when the present polycarboxylic acid is tricarboxylic acid, it is (HO 2 C) 2 (R)CO 2 - and when it is tetracarboxylic acid, it is (HO 2 C) 3 (R)CO 2 - wherein R is a polycarboxylic acid residue, A 2 is a diester group derived from the present polycarboxylic acid, B is a residue derived from the present polyol, and 1, m and n are integers of 0 to 500. The ester to be used in the present invention is preferably a water-soluble ester from the viewpoints of the properties and workability. The most preferred among such esters is an ester of polyethylene glycol with 1,2,3,4-butanetetracarboxylic acid, that is, the ester having the structure as shown below in the foregoing formulas (1) to (3). or B : - (CH 2 CH 2 O) o - wherein o is an integer of 5 to 500. Said ester can be prepared by dehydration esterification of the present polycarboxylic acid and the present polyol. As to the proportions of the present polycarboxylic acid and the present polyol used in the preparation of the ester, preferably 0.01 to 20 moles, more preferably 0.25 to 4 moles, most preferably 0.5 to 1 mole, of the present polycarboxylic acid, per mole of alcoholic hydroxyl group of the polyol. The esterification may be conducted in the absence of a solvent or in the presence of a known catalyst. It is preferred not to use a solvent from the standpoint of the workability. The catalyst to be optionally used is preferably the same substance as a neutralizing agent described later and incorporated into a treating solution in use for depositing the ester on, and/or diffusing the ester into, the liquid ammonia-treated cellulose fibers. The dehydration esterification can be carried out by mixing the two components, heating them to about 80 to about 200°C and optionally distilling off the produced water. The reaction pressure in the dehydration esterification may be atmospheric pressure or reduced pressure. In the present invention, the ester described above is deposited on part or the entire area of the surface of the liquid ammonia-treated cellulose fibers and/or diffused into the fibers. The amount of the ester deposited and/or internally diffused is variable depending on the type of the ester or other factors and indeterminable, but is preferably 0.01 to 30% by weight, more preferably 1 to 20% by weight, based on the liquid ammonia-treated cellulose fibers. A high dirt removability is exhibited when the amount of the ester used is in this range. In depositing the ester on partial or entire exterior of the liquid ammonia-treated cellulose fibers and/or diffusing the ester into the fibers, the present polycarboxylic acid is preferably used in combination with the ester depending on the molar ratio of the present polycarboxylic acid and the present polyol composing the ester. Especially it is recommendable to add the present polycarboxylic acid in combination with the ester when less than 0.5 mole of the present polycarboxylic acid is employed per mole of the alcoholic hydroxyl group of the present polyol. The present polycarboxylic acid may be added in combination even when more than 0.5 mole is used per mole of the alcoholic hydroxyl group of the present polyol. According to the present invention, the present polycarboxylic acid and the present polyol constituting the ester may be individually deposited on and/or diffused into the liquid ammonia-treated cellulose fibers, instead of depositing the ester on and/or diffusing the ester into the liquid ammonia-treated cellulose fibers. As to the proportions of the present polycarboxylic acid and the present polyol separately used in this case, preferably (0.01 to 20 moles, more preferably 0.25 to 4 moles, most preferably 0.5 to 1 mole, of the present polycarboxylic acid is used per mole of alcoholic hydroxyl group of the polyol. The amount of the present polycarboxylic acid deposited and/or internally diffused is variable depending on the type of the present polycarboxylic acid or other factors and indeterminable, but is preferably 0.01 to 20% by weight, more preferably 0.1 to 10% by weight, based on the liquid ammonia-treated cellulose fibers to be processed. The amount of the present polyol deposited and/or internally diffused is variable depending on the type of the present polyol or other factors and indeterminable, but is preferably 0.1 to 30% by weight, more preferably 1 to 20% by weight, based on the liquid ammonia-treated cellulose fibers to be processed. A high dirt removability is exhibited when the amount of each of the two components deposited and/or internally diffused is in this range. In the practice of the present invention, a conventional fiber-softening agent as well as said components may be deposited on and/or diffused into the cellulose fibers. For example, if a polyethylene emulsion or a fiber-softening silicone is deposited on the cellulose fibers or products thereof, an improved feel and enhanced persistence would be imparted to the cellulose fibers or products thereof. Fiber-softening silicones are compounds having, as a basic skeleton, dimethylpolysiloxane containing at least one aliphatic hydroxyl group and/or amino group and/or carboxyl group in the molecule. Preferred silicones are so-called amino-modified silicone, polyether-modified silicone, epoxy-modified silicone and carboxyl-modified silicone. An amino-modified silicone may color treated cellulose fibers or products thereof depending on the type or amount of the silicone. A polyether-modified silicone, epoxy-modified silicone and carboxyl-modified silicone are preferable. These silicones are available in the form of the solid as produced, an emulsion or an aqueous silicone and can be used as such. The amount of the fiber-softening agent deposited and/or internally diffused is preferably 0.01 to 50% by weight, more preferably 0.1 to 10% by weight, based on the product of cellulose fibers to be processed. The ester or the present polycarboxylic acid, the present polyol and the like may be deposited on and/or diffused into the cellulose fibers by various conventional methods such as dipping, spraying, coating and the like. In the practice of the invention, the so-called dipping technique is preferred in which the cellulose fibers to be treated are dipped into a treating solution containing the ester or the present polycarboxylic acid, the present polyol, etc. The dipping technique is described below in detail. The concentration of the ester or the concentrations of the present polycarboxylic acid and the present polyol in the treating solution can be determined by calculation from the squeezing ratio of the treating solution and the amount of the treating solution required to be carried. It is preferable to adjust the treating solution to a pH of 0 to 6, more preferably 2 to 5. If the treating solution has a pH in said range, the cellulose fibers would be given higher dirt removability and enhanced laundry durability. The pH range of the treating solution can be adjusted by adding a neutralizing agent, namely a suitable alkali or salt, to the treating solution. Examples of the neutralizing agent to be used for the adjustment of a pH are sodium hydroxide, sodium bicarbonate, sodium carbonate, sodium percarbonate, sodium borate, sodium metaborate, sodium borohydride, sodium silicate, sodium metasilicate, sodium sulfate, sodium sulfite, sodium thiosulfate, sodium phosphate, sodium metaphosphate, sodium polyphosphate, sodium pyrophosphate, sodium phosphite, sodium hypophosphite, sodium formate, sodium acetate, sodium malate, sodium tartrate and sodium lactate. Salts of potassium, salts of ammonium, and salts of methylamine, dimethylamine, trimethylamine, triethylamine or like volatile lower amines can be used in place of said sodium salts. These neutralizing agents can be used either alone or in combination. The amount of the optional neutralizing agent used is variable depending on the type and the dissolution amount of the ester or the present polycarboxylic acid but is about 0.1 to about 10% by weight, calculated as the concentration in the treating solution. The solvent constituting the treating solution may be an organic solvent but preferably is water from the viewpoints of safety and costs. The form of the treating solution is not specifically limited insoafar as the desired effect can be achieved. A suitable form may be a solution or an emulsion. An aqueous solution is preferred from the viewpoints of treating efficiency and safety. The liquid ammonia-treated cellulose fibers are dipped in the treating solution prepared above to deposit the ester or the present polycarboxylic acid, the present polyol and like components on the fibers and/or to diffuse them into the fibers and then the fibers are heated, usually after squeezing, whereby the cellulose fibers of the present invention are produced. Since the treating solution can be deposited on or diffused into the fibers at a sufficiently high rate, the dipping time and the bath temperature are not specifically limited. Usually the dipping time is 0.1 to 300 seconds, and the bath temperature is 10 to 40°C. Squeezing methods are different depending on the product to be processed, and a suitable method and a proper squeezing ratio can be selected. Usually a preferred squeezing ratio is 30 to 200%. The cellulose fibers are dried after dipping and squeezing. The drying temperature is 40 to 150°C and the drying time is selected according to the temperature. In the invention, subsequently there are heat-treated the cellulose fibers externally or internally having the ester or the present polycarboxylic acid, the present polyol and other components. The heat treatment causes esterification reaction of the present polycarboxylic acid and the present polyol sticking to the fibers for conversion into an ester, and not only the surface of the fibers is partly or completely coated with the ester, but also a reaction occurs between the carboxyl group of the present polycarboxylic acid and the hydroxyl group of the cellulose fibers to give a firm coating film of the reaction product chemically bonded to the exterior and/or the interior of individual fibers. When the ester prepared by the esterification of the present polycarboxylic acid and present polyol is used, the same coating film is formed. If other components than the present polycarboxylic acid and present polyol or the ester, such as a fiber-softening silicone, are deposited on and/or diffused into the fibers, the components are reacted by heat treatment together with the present polycarboxylic acid and the present polyol or the ester to produce a reaction product as said coating film. The heat-treating temperature is preferably 100 to 250°C, more preferably 120 to 200°C. The heat-treating time is preferably 20 seconds to 1 hour. The heat treatment under these conditions provides the cellulose fibers of the present invention with improved dirt removability and enhanced laundry durability. The cellulose 1086Xfibers processed may be subjected to further treatments such as washing with water, soaping and addition of fiber-softening agent and others to give the desired product of cellulose fibers. If the product of cellulose fibers is a thread, the thread may be made into textile, knit, non-woven fabric or the like by conventional methods, and these products are processed into clothes, interior goods, bedding or other end products. Examples of products of cellulose fibers obtainable according to the present invention are outer clothing, intermediate clothing and under clothing. More specific examples are jackets, trousers, skirts, shirts, blouses, nightwears, underwears, stockings, aprons, polo shirts, white robes, gloves, etc. Further examples are embroidery threads, machine cotton, gauzes, flu masks, handkerchiefs, cotton for bedding, pot-holding pads, sneakers, linings and insoles for shoes, towels, dishcloths, covers for armchairs, outer cloth materials for chairs, cushions, bedding covers, blankets made of cotton, blankets made of toweling, etc. In the present invention, the cellulose fibers are, as described above, treated with liquid ammonia, subjected to esterification treatment and are made into a product of cellulose fibers by conventional methods. The product of cellulose fibers according to the invention can be produced also by the following processes. A process is employable which comprises treating the cellulose fibers with liquid ammonia, making the liquid ammonia-treated cellulose fibers into a product thereof, depositing the ester of the present polycarboxylic acid and the present polyol on partial or entire exterior of cellulose fibers and/or diffusing the ester into the fibers, and finally heating the fibers, whereby a product thereof is produced. Another process employable comprises treating the cellulose fibers with liquid ammonia, making the liquid ammonia-treated cellulose fibers into a product thereof, depositing the present polycarboxylic acid and the present polyol on partial or entire exterior of cellulose fibers and/or diffusing them into the fibers, and finally heating the fibers, whereby a product thereof is produced. The conditions for the liquid ammonia treatment, deposition or diffusion of the ester or the present polycarboxylic acid and present polyol and heat treatment are the same conditions as described hereinbefore for the cellulose fibers. Examples. Example 1 There was prepared an aqueous solution of 4% by weight of 1,2,3,4-butanetetracarboxylic acid (hereinafter referred to as "BTC"), 8% by weight of "Polyethylene Glycol #600" and 4% by weight of monosodium phosphate. A liquid ammonia-treated plain cotton fabric piece was immersed in the solution at 25°C for 5 minutes and squeezed at a squeezing ratio of 60%. After drying at 100°C for 10 minutes, the piece was heat-treated at 170°C for 2 minutes, giving a heat-treated test fabric sample (processed fabric sample). The processed fabric sample was washed ten times to provide a washed fabric sample. Example 2 There was prepared an aqueous solution of 8% by weight of BTC, 15% by weight of "Polyethylene Glycol #1000", 8% by weight of carboxy-modified silicone, and 4% by weight of sodium malate. Using the solution as a treating solution, the same procedure as in Example 1 was repeated, giving a processed fabric sample and a washed fabric sample. Example 3 There was prepared an aqueous solution of 4% by weight of BTC, 8% by weight of an adduct of 18 moles of ethylene oxide with bisphenol A and 0.8% by weight of sodium carbonate. Using the solution as a treating solution, the same procedure as in Example 1 was repeated, giving a processed fabric sample and a washed fabric sample. Example 4 There was prepared an aqueous solution of 3% by weight of tricarballylic acid, 5% by weight of "Polyethylene Glycol #600" and 4% by weight of monosodium phosphate. Using the solution as a treating solution, the same procedure as in Example 1 was repeated, giving a processed fabric sample and a washed fabric sample. Example 5 There was prepared an aqueous solution of 3% by weight of citric acid, 5% by weight of "Polyethylene Glycol #6000" and 4% by weight of monosodium phosphate. Using the solution as a treating solution, the same procedure as in Example 1 was repeated except that heat treatment was conducted at 170°C for 3 minutes, giving a processed fabric sample and a washed fabric sample. Example 6 There was prepared an aqueous solution of 4% by weight of BTC, 8% by weight of "Polyethylene Glycol #1000", 1% by weight of an adduct of 40 moles of ethylene oxide with pentaerythritol, 1% by weight of monosodium phosphate and 2% by weight of sodium lactate. Using the solution as a treating solution, the same procedure as in Example 1 was repeated, giving a processed fabric sample and a washed fabric sample. Example 7 There was prepared an aqueous solution of 8% by weight of BTC, 15% by weight of "Polyethylene Glycol #1000" and 4% by weight of sodium hypophosphite. Using the solution as a treating solution, the same procedure as in Example 1 was repeated, giving a processed fabric sample and a washed fabric sample. Example 8 A 4-necked flask reactor equipped with a stirrer was charged with 70 g (0.3 mole) of BTC, 150 g (0.15 mole) of "Polyethylene Glycol #1000" and 20 g of water. The temperature was elevated to 150°C and the reaction system was placed under reduced pressure. While eliminating the produced water, the reaction was continued for 3 hours, giving a viscous liquid of an ester (hereinafter referred to as "ester A"). The ester was found to have a neutralization value of 246 (mg KOH/g) and an ester value of 65 (mg KOH/g). An aqueous solution of 20% by weight of the above-obtained ester A and 4% by weight of sodium hypophosphite was prepared. Using the solution as a treating solution, the same procedure as in Example 1 was repeated, giving a processed fabric sample and a washed fabric sample. Example 9 A 4-necked flask reactor equipped with a stirrer was charged with 23.4 g (0.1 mole) of BTC, 100 g (0.2 mole) of "Polyethylene Glycol #1000" and 20 g of water. The temperature was elevated to 150°C and the reaction system was placed under reduced pressure. While eliminating the produced water, the reaction was continued for 3 hours, giving a viscous liquid of an ester (hereinafter referred to as "ester B"). The ester was found to have a neutralization value of 104 (mg KOH/g) and an ester value of 81 (mg KOH/g). An aqueous solution of 8% by weight of the above-obtained ester B, 4% by weight of BTC and 3% by weight of sodium lactate was prepared. Using the solution as a treating solution, the same procedure as in Example 1 was repeated, giving a processed fabric sample and a washed fabric sample. Comparative Example 1 An aqueous solution of 8% by weight of "Polyethylene Glycol #600" and 4% by weight of monosodium phosphate was prepared. Using the solution as a treating solution, the same procedure as in Example 1 was repeated, giving a processed fabric sample and a washed fabric sample. Comparative Example 2 An aqueous solution of 4% by weight of BTC and 4% by weight of monosodium phosphate was prepared. Using the solution as a treating solution, the same procedure as in Example 1 was repeated, giving a processed fabric sample and a washed fabric sample. Comparative Example 3 The same procedure as in Example 1 was performed except that heat treatment was not conducted, giving a processed fabric sample and a washed fabric sample. Comparative Example 4 A plain cotton fabric piece mercerized with an aqueous solution of sodium hydroxide (namely a plain cotton fabric piece not treated with liquid ammonia) was dipped into the treating solution of Example 1 at 25°C for 5 minutes, and squeezed at a squeezing ratio of 60%. After drying at 100°C for 10 minutes, the piece was heat-treated at 170°C for 2 minutes, giving a processed fabric sample. The processed fabric sample was washed ten times to provide a washed fabric sample. Comparative Example 5 A plain cotton fabric piece was treated with liquid ammonia, giving a processed fabric sample which was washed 10 times to provide a washed fabric sample. Comparative Example 6 A plain cotton fabric piece mercerized with an aqueous solution of sodium hydroxide was dipped into the treating solution of Example 1 at 25°C for 5 minutes, and squeezed at a squeezing ratio of 60%. After drying at 100°C for 10 minutes, the piece was heat-treated at 170°C for 2 minutes and then treated with liquid ammonia, giving a processed fabric sample. The processed fabric sample was washed ten times to provide a washed fabric sample. Test Example 1 The washed fabric samples obtained above in Examples 1 to 9 and Comparative Examples 1 to 6 were tested as follows. (1) Dirt removability test The washed fabric sample was fouled at specified spots with lipstick, soiled motor oil and Indian ink and was left to stand for 2 hours to provide a fouled fabric sample. Then the fouled fabric sample was washed once or twice to evaluate the dirt removability according to the following 5-grade rating: 1. No dirt removed 2. Dirt slightly removed 3. Dirt partly removed 4. Dirt markedly removed 5. Only traces of dirt recognizable, or dirt scarcely recognizable. The results are shown below in Table 1. (2) Antifouling property test A solution containing 0.3 ml/liter of Indian ink and 2.5 g/liter of a household detergent was prepared and placed into a washing machine. The washed fabric sample was washed by the machine to evaluate the antifouling property of the sample according to 5-grade rating by JIS dirt grey scale. Grade 1 is the lowest degree of antifouling property and Grade 5 is freedom from dirt. The results are shown in Table 2. Example 1 Grade 4-5 Example 2 Grade 4-5 Example 3 Grade 4-5 Example 4 Grade 4-5 Example 5 Grade 4-5 Example 6 Grade 4-5 Example 7 Grade 4-5 Comp. Ex. 1 Grade 1 Comp. Ex. 2 Grade 2 Comp. Ex. 3 Grade 1 Comp. Ex. 4 Grade 1 Comp. Ex. 5 Grade 1 Comp. Ex. 6 Grade 1

Claims: Liquid ammonia-treated cellulose fibres which are treated, by at least one of exterior surface coating and impregnation, with an ester of (A) a polycarboxylic acid which has at least three carboxyl groups, and (B) a hydrophilic polyol which has at least one oxyethylene group and at least two alcoholic hydroxyl groups, such that a reaction occurs between carboxyl groups of the polycarboxylic acid and hydroxyl groups of the cellulose fibres. Fibres according to claim 1, wherein the polycarboxylic acid is 1,2,3,4-butanetetracarboxylic acid, tricarballylic acid or citric acid. Fibres according to claim 1 or 2, wherein the hydrophilic polyol is polyethylene glycol or an adduct of ethylene oxide. Fibres according to claim 3, wherein the hydrophilic polyol is an adduct of ethylene oxide with bisphenol A, pentaerythritol or polypropylene glycol. A process for producing liquid ammonia-treated cellulose fibres, which process comprises: (i) treating cellulose fibres with liquid ammonia, (ii) depositing an ester of (A) a polycarboxylic acid which has at least three carboxyl groups, and (B) a hydrophilic polyol which has at least one oxyethylene group and at least two alcoholic hydroxyl groups, on the exterior of the liquid ammonia-treated cellulose fibres, and/or impregnating the liquid ammonia-treated cellulose fibres with a said ester, and (iii) heating the fibres to react carboxyl groups of the polycarboxylic acid with hydroxyl groups of the cellulose fibres. A process for producing liquid ammonia-treated cellulose fibres, which process comprises (i) treating cellulose fibres with liquid ammonia, (ii) depositing a polycarboxylic acid which has at least three carboxyl groups and a hydrophilic polyol which has at least one oxyethylene group and at least two alcoholic hydroxyl groups, on the exterior of the liquid ammonia-treated cellulose fibres, and/or impregnating the liquid ammonia-treated cellulose fibres with the said polycarboxylic acid and the said hydrophilic polyol, and (iii) heating the fibres to cause esterification of the polycarboxylic acid and the hydrophilic polyol and to react carboxyl groups of the polycarboxylic acid with hydroxyl groups of the cellulose fibres. A process according to claim 5 or 6, wherein the treated cellulose fibres obtained are as defined in any one of claims 2 to 4. A process according to any one of claims 5 to 7, which further comprises the subsequent step of forming the fibres into a product thereof. A process according to any of claims 5 to 7 wherein the fibres are formed into a product thereof after step (i) but prior to step (ii). A process according to any one of claims 5 to 9 which further comprises the subsequent step of mix spinning, twisting or knitting the treated cellulose fibres or products thereof with cellulose-free fibres.

Inventors: FUJITANI KANGO, FUKUYAMA YOKO, HONDA KAZUHISA, MIURA HIROYUKI, SAKAI YOSHIAKI, TSUJIMOTO YUTAKA, UNO YOSHITAKA, WATANUKI TOSHIO, FUJITANI, KANGO, FUKUYAMA, YOKO, HONDA, KAZUHISA, MIURA, HIROYUKI, SAKAI, YOSHIAKI, TSUJIMOTO, YUTAKA, UNO, YOSHITAKA, WATANUKI, TOSHIO
Applicants: NEW JAPAN CHEM CO LTD, SHIKIBO LTD, NEW JAPAN CHEMICAL CO.,LTD., SHIKIBO LTD.
Application year: 1995
Main classification: D06M13
IPC codes: D06M101, D06M15, D06M23, D06M11, D06M13