JPH05247843A - Cellulose fiber imparted with shrink resistance and its production - Google Patents

Abstract

PURPOSE:To obtain the subject fiber imparted with excellent and durable shrink resistance by heat-treating cellulose fiber and a specific ester component having plural carboxyl groups, thereby bonding the ester to the fiber through ester bond. CONSTITUTION:A polycarboxylic acid (preferably butanetetracarboxylic acid) is esterified with an aliphatic or alicyclic polyol, e.g. ethylene glycol, preferably polyethylene glycol having a molecular weight of about 200-2,000 to obtain an ester having >=2 carboxyl groups. The ester is impregnated in cellulose fibers and heat-treated to form an ester bond between the carboxyl group of the ester and the hydroxyl group of the cellulose fiber. The ester is bonded to the cellulose fiber through ester bond by this process to obtain a cellulose fiber free from formalin-generation and imparted with excellent and durable shrink resistance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to shrink-proof cellulose fibers and a method for producing the same.

[0002]

2. Description of the Related Art Cellulose typified by cotton is widely used because of its many advantages such as hygroscopicity and texture, but on the other hand, it has a drawback that it tends to shrink. Therefore, various treating agents have been used to overcome such drawbacks. For example, a method has been adopted in which a cellulose fiber is treated with a fibrin-reactive resin containing a urea formalin resin or a glyoxal resin which is a derivative thereof as an active ingredient.

However, the method of treating with such a fibrin reactive resin has the following drawbacks. That is,
When cellulose fibers are treated with a fibrin-reactive resin containing urea formalin resin or its derivative, glyoxal resin, as an active ingredient, it is inevitable that formalin remains in the cellulose fibers even after the treatment. In addition to its peculiar malodor, formalin is known to be a carcinogen, and it not only adversely affects the working environment in the fiber treatment process but also the consumer who uses the final product. In recent years, the safety orientation has been further increasing, and the use of carcinogenic formalin tends to be obliged to tighten regulations and refrain from restraint.

Under the circumstances, therefore, there is a demand for an epoch-making non-form processed cellulose fiber which does not use urea formalin resin or glyoxal resin.

[0005]

In view of the present situation, the inventors of the present invention have conducted extensive studies to provide a cellulose fiber having the above-mentioned drawbacks and having shrink resistance. as a result,
By heat-treating a polycarboxylic acid and an ester having at least two carboxyl groups of an aliphatic or alicyclic polyol and a cellulose fiber, the ester can be firmly bound on the cellulose fiber, and the cellulose fiber is durable. It has been found that excellent shrink resistance can be imparted. The present invention has been completed based on such findings.

That is, according to the present invention, an ester having at least two carboxyl groups of a polycarboxylic acid and an aliphatic or alicyclic polyol and a cellulose fiber are heat-treated to obtain a carboxyl group in the ester and a cellulose fiber. The present invention relates to a cellulose fiber to which shrink resistance has been imparted by subjecting the above-mentioned ester to an ester bond to the cellulose fiber by esterification reaction with the hydroxyl group of.

Cellulose fibers in the present invention include cotton, hemp, rayon and blended fibers containing these fibers, and also products such as woven fabrics, knits and nonwoven fabrics made of these fibers.

In the present invention, the ester that acts on the cellulose fiber is an ester of polycarboxylic acid and an aliphatic or alicyclic polyol, and has at least two carboxyl groups in the molecule.

As the polycarboxylic acid which is one component constituting the above ester of the present invention, conventionally known ones can be widely used, and examples thereof include linear aliphatic polycarboxylic acid, branched aliphatic polycarboxylic acid and alicyclic ring. Group polycarboxylic acids, aromatic polycarboxylic acids, etc. may be mentioned, and these acids may have a halogen atom, a carbonyl group, a carbon-carbon double bond or the like. Specific examples of such polycarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, and the like, and their branched carboxylic acids, maleic acid, fumaric acid, and the like. Aliphatic dibasic acids such as saturated dibasic acid, cyclohexanedicarboxylic acid, tetrahydrophthalic acid and nadic acid, tribasic acids such as tricarballylic acid, aconitic acid, methylcyclohexene tricarboxylic acid, butanetetracarboxylic acid, cyclopentanetetracarboxylic acid Acid, tetrahydrofuran tetracarboxylic acid, tetrabasic acid such as ene adduct of methyltetrahydrophthalic acid and maleic acid, o-phthalic acid, m-phthalic acid,
Examples thereof include aromatic polycarboxylic acids such as p-phthalic acid, trimellitic acid, pyromellitic acid, biphenyltetracarboxylic acid, benzophenonetetracarboxylic acid and diphenylsulfonetetracarboxylic acid. Among these polycarboxylic acids, butanetetracarboxylic acid, which is a water-soluble and tetrabasic acid, is most suitable because it can further exhibit the effect of the present invention that it can impart the cellulose fiber with the shrink-proof property excellent in durability. ..

As the aliphatic or alicyclic polyol which is another component constituting the above ester of the present invention, conventionally known ones can be widely used. Specific examples of the aliphatic polyol include ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, dodecanediol, neopentyl glycol, methylpentanediol and trimethylpentane. Diol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, 1,2-
Polymers of butylene oxide, aliphatic diols such as polytetramethylene glycol, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol, diglycerin, triglycerin, polyglycerin, and further xylitol, sorbitol, mannitol. , Reducing sugars such as erythritol,
Examples include monosaccharides such as xylose, sorbose, arabinose, ribose, erythrose and galactose, and disaccharides such as lactose, sucrose and maltose. Specific examples of the alicyclic polyol include cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, spiroglycol, and geometric isomers thereof. Further, a polyester polyol of the above polyol and polycarboxylic acid is also included in the polyol of the present invention. Among the above polyols, aliphatic or alicyclic diols are preferable. Further, as the above-mentioned polyester polyol, a cross-linked gelled one is not preferable, and at least a solvent-soluble one, preferably water-soluble one is preferable. However, even if it is insoluble in water, it is possible to use one that can be emulsified and solubilized by using a surfactant.

Among the above aliphatic or alicyclic diols,
It is water-soluble and has excellent operability.
Polyethylene glycol having a molecular weight of about 000 is suitable, and polyethylene glycol having a molecular weight of about 400 to 2000 is most suitable. Such polyethylene glycol includes
Fractional components such as ethylene glycol, diethylene glycol, triethylene glycol and tetraethylene glycol may be mixed in. When the molecular weight of ethylene glycol is too large, it becomes difficult to express the effect of the present invention that it is possible to impart the cellulose fiber with the shrink-proofing property excellent in durability, while on the other hand, when the molecular weight is too small,
Although the above-mentioned effects of the present invention are exhibited, production of the ester becomes difficult, which is not preferable in practice.

When an aliphatic or alicyclic diol is used as the aliphatic or alicyclic polyol, the most representative structure of the ester of polycarboxylic acid and the diol is shown below.

(A)-(B)-(A) [A is a group derived from a polycarboxylic acid, and when the polycarboxylic acid is a dicarboxylic acid, (HO ₂ C) (R) CO
₂ , in the case of tricarboxylic acid (HO ₂ C) ₂ (R) C
O ₂ , in the case of tetracarboxylic acid (HO ₂ C) ₃ (R) C
It is O ₂ . B is a residue derived from an aliphatic or alicyclic diol. ] As the ester used in the present invention,
From the viewpoint of workability, those that are water-soluble are preferred. The most preferable ester is an ester of 1 mol of polyethylene glycol and 2 mol of 1,2,3,4-butanetetracarboxylic acid, that is, an ester having the following structure.

[0014]

[Chemical 1]

The composition ratio of the aliphatic or alicyclic diol constituting the above ester to the polycarboxylic acid is 1 mol of the diol and 2 mol of the polycarboxylic acid. But,
There is no problem even if the ester of the present invention contains a polyester or oligoester compound corresponding to a composition of 2 moles or less of polycarboxylic acid with respect to 1 mole of diol mixed during the production of ester.

The cellulose fiber of the present invention is produced, for example, by impregnating the above-mentioned ester into the cellulose fiber and then heat-treating the cellulose fiber.

When the cellulose fiber is impregnated with the ester, the cellulose fiber may be dipped in a treatment liquid containing the ester. The treatment liquid usually comprises the ester and a solvent. Although an organic solvent can be used as the solvent, it is preferable to use water as the solvent in consideration of safety and price. When the ester is not soluble in water, it is preferable to prepare a liquid obtained by emulsifying or solubilizing the ester with a surfactant. Here, as the surfactant, conventionally known ones can be widely used as long as they are active in an acidic aqueous solution, for example, an ethylene oxide adduct of an alkylphenol, an ethylene oxide adduct of a higher alcohol, an alkylbenzene sulfonate, an alkyl sulfate, an alkyl. Examples thereof include betaines, sorbitan fatty acid esters and ethylene oxide adducts thereof, fatty acid monoglycerides and ethylene oxide adducts thereof. In the present invention, an alkylphenol ethylene oxide adduct and a higher alcohol ethylene oxide adduct, which are stable in an acidic aqueous solution for a long period of time and are hardly affected by alkalis for pH adjustment described below, are particularly preferable. The amount of such a surfactant used is not particularly limited as long as the ester can be stably dispersed in water, and is usually 0.1 to 0.1% in the treatment liquid.
About 10% by weight may be blended.

In the present invention, it is desirable to further add a polycarboxylic acid to the treatment liquid. By using the ester and the polycarboxylic acid in combination, the shrinkproof effect of the present invention is further enhanced. The polycarboxylic acid used in combination with the above ester may be the same carboxylic acid as the polycarboxylic acid constituting the ester or may be a different polycarboxylic acid. When the polycarboxylic acid does not dissolve in a solvent such as water, the above surfactant may be used.

The concentration of the ester and the concentration of the polycarboxylic acid in the treatment liquid may be set to the concentration calculated from the squeezing ratio of the treatment liquid and the required impregnation amount. The amount of the ester to be impregnated into the cellulose fibers is usually about 1 to 100% by weight, preferably about 5 to 50% by weight, based on the cellulose fibers. If the impregnated amount of the ester is too small, it becomes difficult to exert the effect of the present invention that it is possible to impart the cellulose fiber with the shrink-proof property having excellent durability, while the effect corresponding to the impregnated amount is obtained even when impregnated in a large amount. Not effective and not economical. The amount of the polycarboxylic acid to be impregnated into the cellulose fiber varies depending on the type of the polycarboxylic acid used and the like and cannot be generally specified, but is usually 0.1 to 50% by weight with respect to the cellulose fiber.
The amount is preferably about 0.5 to 20% by weight. If the impregnated amount of polycarboxylic acid is too small, the effect of combined use with the above ester is insufficient, and even if a large amount is impregnated, the effect corresponding to the impregnated amount is not exhibited and it is not economical.

It is desirable to previously add a pH adjuster to the aqueous solution in which the above ester or the ester and the polycarboxylic acid are dissolved to adjust the pH of the liquid. The pH range is usually in the range of 1 to 6, preferably 2 to 5. If the pH of the liquid is higher than the above range, the shrink-proofing effect tends to be difficult to be exhibited, while if the pH of the liquid is lower than the above range, a decrease in fiber strength tends to be unavoidable due to hydrolysis of cellulose. , Not preferable. As the pH adjuster, an alkali or its salt is usually used. Specific examples of the pH adjuster include sodium hydroxide, sodium bicarbonate, sodium borate, sodium metaborate, sodium silicate, sodium metasilicate, sodium phosphate, sodium metaphosphate, sodium polyphosphate, sodium pyrophosphate. ,
Examples thereof include sodium phosphite, sodium hypophosphite, sodium formate, sodium acetate and the like. The above pH
Instead of sodium as a regulator, potassium, ammonium and the like, and salts of volatile lower amines such as methylamine, dimethylamine, trimethylamine and triethylamine can also be used. These may be used alone or in combination of two or more. The amount of these pH adjusters used varies depending on the amount and type of the above-mentioned ester and polycarboxylic acid dissolved, and cannot be generally stated, but it is usually preferable to add about 0.1 to 10% by weight to the treatment liquid.

In the present invention, the cellulose fibers to be treated are immersed in the treatment liquid prepared as described above, squeezed according to the required impregnation amount, and then dried.

The permeation rate of the treatment liquid of the present invention into the cellulose fibers is sufficiently high, and the immersion time and bath temperature are not particularly limited. Generally, the immersion time is 0.5 to 300 seconds and the bath temperature is 10
Performed at ~ 40 ° C. The drawing depends on the cellulose fiber product to be processed, and an appropriate drawing method and drawing ratio can be adopted for each. Usually, it is preferable that the drawing rate is 40 to 200%. The temperature during the next drying is 40-
The temperature is preferably about 150 ° C., and the drying time may be set appropriately according to the temperature.

When heat treating the cellulose fibers impregnated as described above, the heat treatment temperature is usually 100 to 250 ° C., preferably 120 to 200 ° C., and the heat treatment time is about 30 seconds to 1 hour. Is good. By this heat treatment, the hydroxyl group in the cellulose fiber and the carboxyl group in the ester undergo an esterification reaction, and the ester is firmly bonded to the cellulose fiber by an ester bond. If the heat treatment conditions are milder than the above, the shrink-proofing effect of the cellulose fibers tends to be difficult to be exhibited, while on the other hand, if the conditions are too strict than the above, the cellulose fibers tend to deteriorate and the strength decreases and the fiber yellows. Either of them is not preferable.

The cellulose fiber of the present invention is obtained by impregnating the cellulose fiber with polycarboxylic acid and an aliphatic or alicyclic polyol instead of the above ester.
It is also produced by heat-treating the cellulose fiber. By the heat treatment, the polycarboxylic acid impregnated in the cellulose fiber reacts with the aliphatic or alicyclic polyol to form an ester, and the ester thus formed is a carboxyl group in the cellulose fiber and a cellulose fiber in the cellulose fiber. The hydroxyl group causes an esterification reaction, and the ester is bonded to the cellulose fiber.

As the polycarboxylic acid and the aliphatic or alicyclic polyol used in this method, any of the polycarboxylic acid and the aliphatic or alicyclic polyol constituting the above ester can be used. Further, as the polycarboxylic acid, various carboxylic acids having a hydroxyl group in the molecule such as hydroxy fatty acid such as malic acid, tartaric acid and citric acid can also be used. As the polycarboxylic acid used here, butanetetracarboxylic acid which is a water-soluble and tetrabasic acid is particularly preferable. Water-soluble carboxylic acids such as tricarballylic acid, aconitic acid, and citric acid have good workability and are preferably used compounds. The aliphatic or alicyclic polyol has a molecular weight of 200 to 2000.
Polyethylene glycol of about 0 is particularly suitable. The impregnated amount of the polycarboxylic acid varies depending on the type of the polycarboxylic acid used and cannot be generally specified, but is usually about 0.1 to 50% by weight, preferably 0.5 to 20% by weight with respect to the cellulose fiber that is usually treated. It is preferable to set it to about wt%. If the impregnated amount of polycarboxylic acid is too small, the shrink-proofing effect is insufficient, and even if a large amount of impregnated polycarboxylic acid is impregnated, the effect corresponding to the impregnated amount is not exhibited and it is not economical. Further, the impregnated amount of the above-mentioned polyol varies depending on the type of the polyol used and the like and cannot be generally stated, but it is usually about 0.1 to 100% by weight, preferably 1 to 50% by weight based on the cellulose fiber to be treated.
It is good to set the degree. If the impregnated amount of the polyol is too small, the shrinkproof effect is insufficient, and even if a large amount is impregnated, the effect corresponding to the impregnated amount is not exhibited and it is not economical.

Means for impregnating cellulose fibers with the above-mentioned polycarboxylic acid and aliphatic or alicyclic polyol, means for heating impregnated cellulose, and the like can be performed in the same manner as described above.

The cellulose fiber processed as described above is further subjected to conventional means such as washing with water, soaping, and application of a fiber softening agent to obtain a desired product.

[0028]

EFFECTS OF THE INVENTION According to the present invention, there is provided a cellulose fiber having excellent durability and shrink resistance.

[0029]

EXAMPLES The present invention will be further clarified below with reference to Reference Examples, Examples and Comparative Examples. In the following, "%" simply means "% by weight".

Reference Example 1 Polyethylene glycol # 600 (hydroxyl value 181) 6
300 g of 2 g (0.1 mol), 1,2,3,4-butanetetracarboxylic acid 46.8 g (0.2 mol) and water 8 g
The reaction system was put under reduced pressure, and the temperature was raised to 150 ° C. The reaction was continued while removing the produced water, and after 3 hours, a viscous liquid was obtained. The hydroxyl value of this product is a trace amount, and the neutralization value is 336 (mgKOH
/ G). This ester is hereinafter referred to as "ester A".

Reference Example 2 Polyethylene glycol # 1000 (hydroxyl value 107)
The above reference example 1 except that 104 g (0.1 mol) was used.
A viscous liquid was obtained in the same manner as in. The hydroxyl value of this product was a trace amount, and the neutralization value was 246 (mgKOH / g). This ester is hereinafter referred to as "ester B".

Reference Example 3 Polytetramethylene glycol # 650 (hydroxyl value 17
2) A viscous liquid was obtained in the same manner as in Reference Example 1 except that 65 g (0.1 mol) was used. The hydroxyl value of this product was a trace amount, and the neutralization value was 322 (mgKOH / g). This ester is hereinafter referred to as "ester C".

Reference Example 4 Hydroxyl value 1 consisting of succinic acid and triethylene glycol
42 except that 79 g of polyester polyol 42 is used.
A viscous liquid was obtained in the same manner as in Reference Example 1 above. The hydroxyl value of this product is a trace amount, and the neutralization value is 286 (mgKO
H / g). This ester is hereinafter referred to as "ester D".
Say.

Example 1 As a test cloth, a cotton knit cloth (Kanoko) on which markings of 20 cm × 20 cm were previously made (30 cm × 30 c)
m) was used.

An aqueous solution was prepared by dissolving 10% of the ester A obtained in Reference Example 1 and 4% of sodium phosphate monobasic. The test cloth was immersed in the aqueous solution at 25 ° C. for 5 minutes and squeezed at a drawing rate of 80%. After drying at 100 ° C. for 10 minutes, heat treatment was performed at 180 ° C. for 3 minutes to obtain a heat-treated test cloth.

Example 2 A heat treatment test was conducted in the same manner as in Example 1 except that an aqueous solution prepared by dissolving 10% of the ester B obtained in Reference Example 2 and 4% of monosodium pyrophosphate was used. Got the cloth.

Example 3 5% of the ester A obtained in Reference Example 1, 1, 2, 3, 4
A heat-treated test cloth as in Example 1 above, except that an aqueous solution containing 6% butanetetracarboxylic acid, 4% monobasic sodium phosphate and 4% sodium hypophosphite was used. Got

Example 4 13% of the ester B obtained in Reference Example 2, 1, 2, 3,
Heat treatment test in the same manner as in Example 1 except that an aqueous solution containing 6% of 4-butanetetracarboxylic acid, 4% of sodium phosphate monobasic and 4% of sodium hypophosphite was used. Got the cloth.

Example 5 An isopropanol solution was prepared by dissolving the ester C obtained in Reference Example 3 in a proportion of 10%. The test cloth used in Example 1 was immersed in the solution for 5 minutes at 25 ° C., and the drawing ratio was 12
After squeezing to 0%, it was dried at 80 ° C. for 5 minutes. Next 1,
An aqueous solution in which 2,3,4-butanetetracarboxylic acid was dissolved at a ratio of 6% and sodium phosphate monobasic at a ratio of 8% was prepared, and the test cloth was immersed in the aqueous solution at 25 ° C for 5 minutes, and the squeezing ratio was reduced. Squeezed at 80%. After drying at 100 ° C. for 10 minutes, heat treatment was performed at 180 ° C. for 3 minutes to obtain a heat-treated test cloth.

Example 6 10% of the ester D obtained in Reference Example 4, 1, 2, 3,
A heat-treated test cloth was obtained in the same manner as in Example 1 except that an aqueous solution in which 6% of 4-butanetetracarboxylic acid and 6% of sodium carbonate were dissolved was used.

Example 7 1,4,2,3,4-butanetetracarboxylic acid was dissolved in 4%, polyethylene glycol # 600 was dissolved in 2% and monobasic sodium phosphate was dissolved in 4%. A heat-treated test cloth was obtained in the same manner as in Example 1 above.

Example 8 1,2,3,4-butanetetracarboxylic acid in 4%, polyethylene glycol # 1000 in 2%, monosodium phosphate in 2% and sodium hypophosphite in 2%. A heat-treated test cloth was obtained in the same manner as in Example 1 except that the dissolved aqueous solution was used.

Example 9 1,2,3,4-butanetetracarboxylic acid 4%, polymethylenetetramethylene glycol # 650 2%, monosodium phosphate 2%, sodium hypophosphite 2%
% And coconut alcohol ethylene oxide 10 mol adduct were emulsified at a ratio of 4% to obtain a heat-treated test cloth in the same manner as in Example 1 except that an aqueous dispersion was used.

Example 10 Hydroxyl value 1 consisting of succinic acid and triethylene glycol
42% polyester polyol 4%, 1,2,3,4
4% butanetetracarboxylic acid, 4% monosodium pyrophosphate and 10% coconut alcohol ethylene oxide
A heat-treated test cloth was obtained in the same manner as in Example 1 except that an aqueous dispersion obtained by emulsifying the molar adduct at 4% was used.

Example 11 3% tricarballylic acid, polyethylene glycol # 6
A heat-treated test cloth was obtained in the same manner as in Example 1 except that an aqueous solution containing 2% of 00 and 4% of sodium phosphate was used.

Example 12 An aqueous solution containing 10% citric acid, 2% polyethylene glycol # 600 and 4% monobasic sodium phosphate was used, and the heat treatment was carried out at 200 ° C. for 3 minutes. A heat-treated test cloth was obtained in the same manner as in Example 1 above.

Comparative Example 1 The same procedure as in Example 1 was repeated except that soft water was used instead of the aqueous solution prepared by dissolving 10% of the ester A obtained in Reference Example 1 and 4% of sodium phosphate monobasic. A heat-treated test cloth was obtained.

Comparative Example 2 A dry test cloth was obtained in the same manner as in Example 1 except that the heat treatment was not performed.

Comparative Example 3 A dry test cloth was obtained in the same manner as in Example 7 except that the heat treatment was not performed.

Comparative Example 4 A heat-treated test cloth was obtained in the same manner as in Example 7 except that an aqueous solution prepared by dissolving 2% polyethylene glycol # 600 and 4% sodium monobasic phosphate was used.

Comparative Example 5 Example 5 was repeated except that an aqueous solution containing 4% 1,2,3,4-butanetetracarboxylic acid and 4% sodium monobasic phosphate was used. A heat-treated test cloth was obtained.

Each of the treated test cloths obtained in Examples 1 to 12 and Comparative Examples 1 to 5 was washed and dried with a tumbler dryer, which was repeated 10 times, 20 times and 30 times. The marking distance of the test cloth after the above operation was measured, and the ratio to the distance immediately after the heating or drying treatment was determined to be the shrinkage rate. The results are shown in Table 1.

[0053]

[Table 1]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koichi Murai 4-6-6 Tenjin, Nagaokakyo-shi, Kyoto (72) Inventor Miaki Sakai 1-23-6, Shirakashi-cho, Kashihara-shi, Nara (72) Inventor Miura Hiroyuki 175 Shinkaikai, Gohihocho-cho, Konan-shi, Aichi (72) Inventor Hiroshi Tsujimoto 1-1-1, Takasu-cho, Nishinomiya-shi, Hyogo Mukogawa housing complex No. 2 Building No. 918

Claims (3)

[Claims] 1. A polycarboxylic acid and an ester having at least two carboxyl groups of an aliphatic or alicyclic polyol and a cellulose fiber are heat-treated to remove the carboxyl group in the ester and the hydroxyl group in the cellulose fiber. Cellulose fibers that have been subjected to an esterification reaction and are provided with shrink resistance by binding the above ester to the cellulose fibers through an ester bond. 2. A cellulose fiber is impregnated with an ester having at least two carboxyl groups of a polycarboxylic acid and an aliphatic or alicyclic polyol, and the cellulose fiber is heat-treated to give the above ester to the cellulose fiber. The method for producing a cellulose fiber according to claim 1, wherein the cellulose fiber is bound by an ester bond. 3. A cellulose fiber is impregnated with a polycarboxylic acid and an aliphatic or alicyclic polyol, and then the cellulose fiber is heat-treated to esterify the polycarboxylic acid and the aliphatic polyol to form an ester. The method for producing a cellulose fiber according to claim 1, wherein the produced ester is bonded to the cellulose fiber through an ester bond.