JPH0377295B2 - - Google Patents

Description

Claim 1: A textile fabric that is resistant to static charge build-up, the fabric being capable of absorbing up to about 50% moisture by weight of the fibers without loss of mechanical strength and other textile properties. contains at least 1% by weight of interlocked hydrophilic fibers, the hydrophilic fibers having a Rockwell hardness in the range of about 40 to about 60, and containing alpha, beta ethylenically unsaturated carboxylic acids, alpha,
consisting of a linear hygroscopic homopolymer of monomers selected from the group consisting of beta-ethylenically unsaturated sulfonic acids, hydroxyalkyl esters of these acids, and hydroxyglycidyl esters of these acids; having a molecular weight within the range of about 100,000 to about 500,000, a softening point within the range of about 210°C to about 245°C, and a glass transition temperature Tg of about 115°C or higher;
and the polymer is crosslinked at a crosslink density within the range of one chemical crosslink per about 40 to about 100 repeating monomer units of the polymer.

2. The fabric according to claim 1, comprising 2 to 10% by weight of the hydrophilic fiber fabric.

3. The fabric according to claim 2, wherein the hydrophilic fibers are made of cross-linked polyacrylic acid.

4. The fabric according to claim 2, wherein the hydrophilic fibers are made of cross-linked poly(hydroxyethyl methacrylate).

5 The monomer is acrylic acid, methacrylic acid, crotonic acid, hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate,
The fabric of claim 1 selected from the group consisting of hydroxypentyl acrylate, hydroxypropyl methacrylate and hydroxybutyl methacrylate.

6. Another textile fiber 90 selected from the group consisting of polyester fibers, polyamide fibers and polyacrylonitrile fibers or mixtures thereof.
3. The fabric of claim 2, containing ~98% by weight.

7. The fabric of claim 6, wherein the fabric weighs less than 2 grams per square foot, has a moisture absorption in the range of about 30 to about 50, and has an electrical conductivity of at least 10 ⁻¹⁰ mho. fabric.

8. Underwear worn in contact with the human body, manufactured from the fabric according to claim 1, as a clothing product.

9 Claim No. 8 which is bread tasting
Products listed in section.

10. The product according to claim 8, which is stockings.

11. The product according to claim 8, which is underwear.

12. A panty pants made of the fabric according to claim 7, which is used as a clothing product.

13. Claim 12, wherein the hydrophilic fibers are comprised of cross-linked polyacrylic acid or cross-linked poly(hydroxyethyl methacrylate).
Clothing products listed in section.

14. Stockings made of the fabric according to claim 7, as a clothing product.

15. The clothing article of claim 14, wherein said hydrophilic fibers are comprised of cross-linked polyacrylic acid or cross-linked poly(hydroxyethyl methacrylate).

16. Underwear made of the fabric according to claim 7, as a clothing product.

17. Claim 16, wherein the hydrophilic fibers are comprised of cross-linked polyacrylic acid or cross-linked poly(hydroxyethyl methacrylate).
Clothing products listed in section.

18 Linear monomer selected from the group consisting of alpha, beta ethylenically unsaturated carboxylic acids, alpha, beta ethylenically unsaturated sulfonic acids, hydroxyalkyl esters of these acids, and hydroxyglycidyl esters of these acids a hygroscopic homopolymer, wherein about 40% of the polymer
consisting essentially of said polymers that are cross-linked at a cross-linking density in the range of 1 chemical cross-link per about 100 repeating monomer units, and said polymers are cross-linked at a cross-linking density in the range of about 100,000 to 500,000 repeating monomer units. Molecular weight of about 210℃~approx.
A hygroscopic fiber having a softening point in the range of 245°C and a glass transition temperature Tg of about 115°C or higher.

Description The present invention provides anti-static, comfortable and abrasion-resistant fabrics suitable for the manufacture of women's underwear, stockings, pantyhose, etc.
It is related to. More particularly, the present invention provides special fibers made from cross-linked high molecular weight linear hygroscopic polymers that are capable of absorbing large amounts of water without deterioration of the textile properties of the fibers. Textile fiber (specialty
This relates to textiles containing textile fibers.

sheer fabrics from many types of fibers such as silk, nylon, polyester, etc.
is known to be manufactured. These thin fabrics are used in many types of garments, especially underwear such as underpants, undershirts, stockings, pantyhose, etc.

In an attempt to improve the properties of these articles of clothing made from knitted fabrics, monofilament down to 7 denier per filament, multilobal cross-sections, etc.
Modifications to textile structures have been made, such as substituting non-woven fabrics for fabrics, bicomponent filaments, and knitted fabrics. Despite these research efforts, all of the current textile fibers used in the production of thin fabrics for use in articles of clothing such as women's underwear, stockings, pantyhose, etc. It has some drawbacks. for example,
These fabrics still feel cold and clammy, are uncomfortable, tend to be sticky to the skin, and exhibit a tendency to generate static charges. Research in this area has shown that these drawbacks result, at least in part, from insufficient water absorption of the fibers from which textile products are made. Many attempts have therefore been made to improve the water absorption properties of textile fibers.

For example, it is known to graft acrylic acid and methacrylic acid onto nylon textile filaments with the aid of radiation activation of the polyamide filament surface. As another method, acrylic fibers have been developed that have a water absorption capacity of about 15% due to the formation of microcapillary systems during filament spinning. Yet another development is the production of modified polyester filaments for women's underwear in which the water absorption of the polyester is increased to about 15% by partial sulfonation of the aromatic portion of the macromolecule.

Yet another way to increase the overall absorbency of these types of fabrics is to add relatively high absorbency fibers during the manufacturing process. Man-Made Fibers by R.W. Moncrief, 6th edition,
(1975), p. 324, representative moisture recovery properties of several conventional fibers made from various natural, man-made and synthetic fibers.
regains) are shown in the table below. Fiber recovery (%) Wool 16 Nylon 4.0 Polyester 0.4 Acrylic 0.9 Cotton 8.5 Viscose 12.0 Cellulose acetate 6.5 Fibers made from amine-containing polymers cross-linked with polyfunctional or difunctional alkylating agents Fabrics containing ~100% are described in Richter et al., U.S. Pat. It is characterized by its water recovery properties. The fiber is 50-100 mol%
methyl acrylate, ethyl acrylate, acrylamide, methacrylamide, N-alkyl-substituted acrylamide, and acrylonitrile.

The inclusion of acrylic fibers in undergarments that have improved hydrophilic and antistatic properties balanced with physical properties such as knot strength and elongation has been developed by American Cyanamid.
Shimoda transferred to the company
Suggested in other US Pat. No. 3,733,386. These acrylic fibers are made from a polymer containing at least 80% by weight of acrylonitrile and a copolymerizable monomer by treating the acrylic fibers in a stretched, swollen wet gel state with a cross-linking agent and cross-linking them. by hydrolyzing the bonded wet gel fibers with a mineral acid, optionally treating the hydrolyzed crosslinked wet gel fibers with an aqueous solution of an ammonium or metal salt, and drying the fibers. Manufactured. Optional treatment with an aqueous salt solution imparts antistatic properties to the fibers. Following the examples of this patent, only about 15% moisture recovery is obtained. Moreover, it was possible to have a surface resistance of less than 10 ¹⁰ ohms only when an optional treatment with an aqueous salt solution was carried out. The above values are generally accepted maximum values to eliminate undesirable high static charge build-up.

Yamamoto et al.'s U.S. patents
3626049, 3759849 and 3846386 disclose crosslinked acrylic fibers consisting primarily of acrylonitrile and woven or knitted fabrics made therefrom that have hydrothermal resistance and a silky texture or feel. These fibers are capable of polymerizing (a) vinyl monomeric materials consisting primarily of acrylonitrile and (b) monomers having halogenated s-triazinyl or halogenated pyrimidinyl groups in an acidic medium. The fibers obtained by extruding an acidic solution of the copolymer obtained by copolymerization in the presence of an unsaturated monomer and/or (d) protein are heat-treated to cause cross-linking.

Acrylonitrile copolymer fibers and filaments that are cross-linked to improve dimensional stability are disclosed in the U.S. patent of Radlmann et al.
4131724. According to this patent, 1
An acrylonitrile copolymer containing at least 20 mVal of carboxy groups per kg of polymer is dissolved in a polar solvent containing at least one polyoxazoline at a temperature of 20 DEG to 120 DEG C., and the solution is spun into filaments. Cross-linking is then carried out by heating the filament to a temperature of 120-190°C to react the carboxyl groups with the oxazoline rings to form ester and amide structures. However, in order to reach a satisfactory state regarding comfort, antistatic properties, etc., subsequent studies have shown that hydrophilic fibers with a recovery of at least about 8% have a lower recovery of about 2%. It has been found that it is necessary to add fiber in substantial amounts, ie between 15 and 30%. However, the addition of such relatively large amounts of hydrophilic components may affect the modulus, tensile strength, and suppleness.
and various adverse effects including deterioration of creep properties.

Therefore, one object of the present invention is to
Including articles of clothing in contact with the human body, which may be non-woven or knitted and which are antistatic, comfortable and abrasion resistant, in particular underwear, stockings, pantyhose, etc. To provide a lightweight fabric that can be used for manufacturing women's underwear.

Another object of the present invention is to provide specialty fibers for textile applications where it is necessary to be able to absorb large amounts of moisture without deteriorating tensile strength and other fiber properties.

Another object of the invention is to provide filaments and fibers with high moisture absorption and antistatic properties that can be used in textiles for making clothing and other articles.

Yet another and special object of the present invention is to crosslink high molecular weight materials such as polyacrylic acid and poly(hydroxyethyl methacrylate) which do not impair their textile properties, such as tensile strength, when tested in the wet state. It is an object of the present invention to provide a lightweight, rub-resistant and antistatic pantyhose comprising textile fibers made from a linear homopolymer made from a polyester resin.

These and other objects, which will become apparent from the description below, are generally directed to linear hygroscopic monopolymers having only carbon-to-carbon bonds in the polymer backbone with hydrophilic side chains in the repeating units. This is achieved by including in the fabric at least about 1% by weight of novel specialty fibers formed from polymers, which include alpha, beta-ethylenically unsaturated aliphatic carboxylic acids, alpha, beta-ethylenically unsaturated fats, etc. sulfonic acids, hydroxy-alkyl esters of these aliphatic carboxylic acids and sulfonic acids, and grindyl esters of these aliphatic carboxylic acids and sulfonic acids; Such polymers have a molecular weight in the range of about 100,000 to about 500,000, a softening point in the range of about 210°C to about 245°C, and a
The homopolymer has a glass transition temperature Tg of 115° C. or higher, and the homopolymer is crosslinked at a crosslink density within the range of one crosslink per about 40 to about 100 repeating monomer units of the homopolymer. has been done. These specialized textile fibers can absorb up to about 40% moisture by weight of the fiber without compromising mechanical strength and other textile properties, and even more
It is characterized by a Rockwell hardness in the range of approximately 60.

According to the present invention, any of these specialty fibers can be assembled or constructed into various types of fabrics, such fabrics including plied yarns.
fabrics containing interlocked yarns or threads made from yarns formed from fibers or filaments, with or without adhesive bonding at crossing or interlocking points; Fabrics of a felt-like nature that are interlaced or interlocked are included. The former type of fabric is a woven, knitted, netted, knotted or braided fabric formed from yarns comprising fibers or filaments of this particular type. Something can happen.
Nonwoven fabrics contemplated by the present invention can also be obtained by randomly distributing a large number of short or continuous lengths of fibers. This includes the nature of the fabric that was carded and optionally produced multiple carded webs;
obtained by overlapping one another in the machine direction of various webs arranged parallel to each other or at various angles for the purpose of imparting anisotropy and isotropy in properties, especially with respect to strength and cleavage. Such textiles are also included. Also included are intermediate forms of fabrics, also referred to as hybrid forms, such as the type of fabric known as needle felt, in which the woven or knitted fabric has fibers or filaments punched through the substrate fabric. .

Although the various textiles may be composed entirely of fibers, filaments, and yarns of the type described above, they are preferably comprised of fibers or filaments of this type and other types of fibers or filaments of natural or man-made origin. It is composed of a mixture of
Similarly, the fabric can also consist of a mixture of yarns consisting of fibers or filaments of the above-mentioned types and yarns made from other types of fibers, natural or man-made. Therefore, textiles include cotton, wool, silk, linen, nylon, polyethylene terephthalate (e.g.
Dacron), regenerated cellulose rayon, cellulose acetate, casein, vinyl resin fibers, such as fibers, filaments or yarns of copolymers of vinyl chloride and vinyl acetate or acrylonitrile. The proportion of fibers, filaments or yarns made from cross-linked high molecular weight hygroscopic homopolymers in the fabric can vary widely from 1 to 100%. However, e.g. tensile strength,
A proportion of 1 to 10% by weight, especially 2 to 10% by weight, is perfectly suitable for improving the antistatic properties without adversely affecting the mechanical properties of the fabric and the textile properties such as modulus, hand or feel. It has been found that

Glass yarns woven at intervals through a fabric consisting of yarns made from the fibers of the invention arranged in alternating relationship with reinforcing agents to improve the strength of the fabric, such as glass fibers or filament yarns. Also within the scope of the present invention are fabrics such as those that are covered with.

The essential feature of the fabrics of the invention is that they are formed from cross-linked high molecular weight hygroscopic linear homopolymers of ethylenically unsaturated carboxylic or sulfanic acids or their hydroxyalkyl esters or glycidyl esters. The fibers, filaments or yarns comprise at least about 1% by weight of the fabric, preferably at least 2% and especially 2-10% by weight of the fabric.

The filaments, fibers or yarns and the fabrics made therefrom are subjected to other common finishing steps such as crimping, curling, twisting, sizing, softening or lubricating for weaving, knitting and It can also facilitate other textile operations.

The filaments, yarns or strands produced by the above process steps can be used in the production of various types of textiles. However, they are particularly useful in the production of lightweight thin-type fabrics, such as those used in the production of clothing, especially familiar clothing, such as underwear, including underwear, shirts, stockings, pantyhose, etc. .

The fibers and filaments of the invention can be used with all natural and synthetic materials, but include nylon,
Mixtures with polyacrylics and polyesters are particularly suitable for thin fabrics. In the case of continuous filaments and yarns for stockings, pantyhose, etc., the filaments may be co-twisted with the other components of the fabric. For nylons with moisture recovery properties between 3.2 and 3.7%, the ^reciprocal
2 to 4 to reach a conductivity of ohms or higher.
% by weight of special fibers is sufficient. It is generally accepted that static charge problems do not arise above 10 ^-10 mho.

Most of the textile materials in textiles are e.g.
In order to make the tailored fabric sufficiently conductive to avoid appreciable static damage, it is necessary to make the tailored fabric sufficiently conductive to avoid appreciable static damage if it is made of acrylic or polyester with a much lower moisture recovery, such as between 0.4 and 0.8%.
It has been found that up to 10%, preferably 4-10%, of specialty fibers should be added. In the case of spun yarns such as underwear, shirts, etc., the special fibers of the present invention are mixed with other main components in the form of staple fibers in appropriate proportions to obtain the desired electrical conductivity.

Relatively small amounts, for example about 2-10%, of conductive filaments or fibers do not substantially affect the mechanical properties of the yarns and fabrics of the final textile product.

In particular, textiles that are particularly suitable for making everyday clothing have a weight of less than 2 g per square foot, a tensile modulus of at least about 30 g based on a 1 denier fabric cross-section, a 1 denier a tensile strength of at least 3 g based on the fabric cross-section, an elongation at break of at least 30%, a moisture absorption in the range of about 30 to about 50% by weight of the dry fabric and of at least 10 ^-10 (ohm cm) ^-1 Includes electrically conductive woven, non-woven or knitted fabrics, which include the novel specialty fiber fabric according to the present invention.
Contains 10% by weight.

These fabrics are particularly useful in the manufacture of clothing products, especially underwear, pantyhose and stockings, which are antistatic, comfortable and abrasion resistant, with a dry weight of 35
retain their mechanical, thermal, electrical and physiological properties even after absorbing moisture of % to 40% or more.

Part of the present invention is that cotton as well as other natural cellulosic fibers, such as hemp, flax and ramie, have relatively high moisture equilibrium contents (up to about 15%) without compromising textile strength when tested in the wet state. ) is based on the observation that On the other hand, all viscose rayons lose up to 70% of their tensile strength in the wet state at average moisture contents of 10-12%. It is believed that this difference is largely due to the considerably higher molecular weight and crystallinity of natural cellulose fibers. For example, the molecular weight of cellulose fibers is more than 10 times that of rayon and the degree of crystallinity is higher, up to about 95%.

To produce synthetic fibers with a high moisture absorption capacity of up to about 50% moisture recovery, which is the amount necessary to provide substantial improvement in fabrics used to make clothing, such as underwear. for,
It is necessary to use synthetic polymeric materials having a molecular weight of at least about 100,000 to about 500,000.
However, for such high molecular weight polymeric materials with hydrophilic groups attached to the polymer backbone, a high degree of crystallinity cannot be obtained due to the irregular structure of the highly hygroscopic chains. Accordingly, the present invention uses cross-linking of polymer chains to replace the crystallinity of natural cellulosic materials to provide the same high strength properties as natural cellulosic (crystalline) fibers.

Textile fiber modulus, tensile strength,
In addition to having a high molecular weight capable of providing the necessary mechanical properties, including elongation, the polymeric materials used in the present invention should provide fibers that meet the following other requirements: It must be capable of: (a) moisture recovery, i.e. the ability to absorb up to about 40% by weight of moisture without deterioration of the textile properties; (b) antistatic properties, i.e. a surface resistance of less than 10 ¹⁰ ohms. (c) Washing and dry cleaning resistance, i.e. up to 25 washes and/or more without loss of mechanical properties, fading, etc.
(d) must be resistant to atmospheric influences, i.e., resistant to light, oxygen, ozone and acidic impurities without loss of mechanical properties or fading; No.

The fabric containing the special fiber of the present invention in a small amount of about 10% by weight satisfies all of the above conditions, and at the same time provides comfort that is essential for clothing articles, especially women's underwear, pantyhose socks, stockings, etc. Provides the required degree of friction resistance, friction resistance and antistatic properties.

The filaments or fibers of the present invention are alpha,
Beta ethylenically unsaturated aliphatic carboxylic acids,
By cross-linking very thin filaments or fibers of linear hygroscopic homopolymers of alpha, beta ethylenically unsaturated sulfonic acids, hydroxyalkyl esters of these acids, and hydroxy, glycidyl esters of these acids. The resulting useful homopolymers contain at least
100,000, especially 100,000 to 500,000, most preferably about 150,000 to about 400,000.

Generally has 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms.
monomers can be used. Examples of alpha, beta unsaturated aliphatic carboxylic acids include crotonic acid,
Acrylic acid, methacrylic acid, ethacrylic acid, alpha-isopropylidene acrylic acid, alpha-vinyl acrylic acid, and the like are included. Among these, acrylic acid and methacrylic acid are preferred. Polyacrylic acids having molecular weights up to and above 500,000 are commercially available and are particularly suitable for use in the present invention.

As examples of ethylenically unsaturated aliphatic sulfonic acids, any of the above carboxylic acids in which the carboxylic acid (-COOH) group is replaced by a sulfonic acid ( _-SO3H ) group can be used. Suitable examples of olefinic unsaturated sulfonic acids include vinylsulfonic acid and p-styrenesulfonic acid.

The hydroxyalkyl esters of these aliphatic carboxylic acids and sulfonic acid esters are 1-
It can have 3 hydroxyl groups, preferably 1 or 2 hydroxyl groups, and most preferably 1 hydroxyl group. The alkyl portion of the hydroxyalkyl esters can have 1 to 8, preferably 1 to 4, carbon atoms. Examples of hydroxyalkyl esters include 2-hydroxyethyl acrylate,
2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 5-hydroxypentyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3
-Hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate and the corresponding hydroxyacrylates and hydroxymethacrylates of sulfonic acids. Among these, hydroxyethyl methacrylate is the preferred monomer, and high molecular weight poly(hydroxyethyl methacrylate) is readily commercially available.

Examples of hydroxyglycidyl esters of aliphatic carboxylic acids and sulfonic acids include, for example, hydroxyglycidyl esters of acrylic acid, crotonic acid, vinylsulfonic acid and p-styrenesulfonic acid.

To produce fine textile monofilaments of 7 denier or less from these linear hygroscopic polymers, wet spinning is performed prior to crosslinking the polymers to allow unrestrained laminar flow through the spinneret. do. This is readily accomplished by preparing an aqueous spinning solution of the polymer in sol form having a solids concentration of from about 5 to about 35% by weight, depending on the molecular weight of the polymer, and preferably from about 15 to 25% by weight. The spinning solution can be coagulated in an aqueous salt solution, which removes water from the polymer filament by the osmotic action of the salt. This converts the polymer sol into a non-crosslinked gel, which can also be converted reversibly into a solution again. Gelatinous filaments, in which the individual macromolecules are held together only by van der Waals forces or hydrogen bonds, can be oriented to the desired extent by stretching. After reaching this stage, the filaments are transferred into a second bath containing a cross-linking agent, where the filaments are cross-linked by the action of covalent chemical bonds.

The production of artificial and synthetic filaments from spinning solutions of non-crosslinked polymeric materials by subsequent spinning, drawing and crosslinking is generally known in the art. Suitable processes applicable for the high molecular weight linear hygroscopic polymers used in the present invention are disclosed, for example, in US Pat. Nos. 3,140,265 and 3,733,386.

In a preferred process, the finely powdered polymeric material is added to the required amount of distilled water and stirred gently until completely dissolved. Depending on the molecular weight of the polymer, the concentration of the spinning solution is in the range of 5-35%, with a preferred range of 15-25%. In order to obtain smooth spinning, the absolute viscosity of the spinning solution (absolute viscosity)
should be between 20 and 2000 poise measured at 20°C. Within this range of spinning solution viscosity 80-200
Spinning speeds between yards per minute are obtained. The spinning solution must be evacuated and carefully filtered. Air removal can be carried out under vacuum while slowly passing the solution through the disk-shaped container. Filtration can be carried out using a candle filter similar to that used in the viscose rayon process. Since the spinning solution is substantially neutral (between 6.5 and 7.2), woven or non-woven cotton or rayon fabrics can be used extensively. After a period of time, preferably 100~
The solution having a viscosity between 300 poise is preferably pumped to the spinneret using a gear pump.
The reason is that it does not allow air into the spinning solution. 40 to 40 each having a diameter of about 0.080mm
Satisfactory results are obtained using a spinneret with 72 holes. It is also advantageous to use a conically shaped counter sink having a length approximately half the length of the spinneret channel.

Staple fibers can also be produced from a spinneret of otherwise the same design and dimensions but with 4000 holes.

The spinning bath is kept in the range between 25 and 45 °C;
and consists of a neutral or acidic salt solution,
For example, a concentration range of about 15-20% _NH4Cl gives satisfactory results. As is known from the spinning of viscose rayon, the cross-sectional area of the filament is influenced by the bath chemistry and concentration. Add about 0.5-10% to the spinning bath to obtain the desired cross-sectional area.
It is advantageous to add H ₂ SO ₄ in the range between.

As the threads enter the bath, they are osmotically dehydrated and converted into a stretchable gel. They are guided onto a first roller and then onto another roller, e.g. at a distance of about 2.5 m, having a surface speed of e.g. Orientation is performed. As a result of this stretching, the individual macromolecules are collimated, stretched, and to some extent glide along each other. The reason is that at that point they are not cross-linked by chemical bonds. After exiting the end of the first bath, the filaments are led into a second bath where they are cross-linked by chemical bonds. One effective method of cross-linking is to include in the second bath a water-soluble cross-linking agent that can be absorbed by the gel filament as it passes through the second bath. Such difunctional cross-linking agents include, for example, dicarboxylic acids or anhydrides, glycols or diamines,
Alternatively, other difunctional reactive compounds are included. The cross-linking reaction is carried out thermally (40-50
°C) or under the influence of a catalyst. After exiting the second bath at a speed of 100 to 150 yards per minute, the filament is dried and wound onto a spool in a generally known manner.

The cross-linking step can also be carried out without chemical reagents by exposing the filament to the action of ionizing radiation or fast electrons. In this case a second bath is not necessary and the filament is exposed to radiation while being wound in a spool.

The invention is illustrated by the following examples.

Example 1 A solution of polyacrylic acid having a molecular weight of 260,000 was prepared in distilled water at 40°C with a concentration of 18.5% polymer. The solution was vented in a vacuum system for 24 hours and then transferred using a gear pump through a candle filter to a spinneret with 40 holes, each 0.080 mm in diameter. Add this solution to 6%
Extruded into a 40 °C bath containing NH ₄ Cl, 11% MgSO ₄ and 1.2% H ₂ SO ₄ . The gel filament formed immediately after contact of the solution with the bath was supported by a glass roll and sent back and forth therethrough at a speed of 75 yards per minute over a distance of approximately 18 feet. At the end of this coagulation period, the filament contains 2.5% ethylenediamine and 12% ethylenediamine in water.
A second bath containing NH ₄ Cl was introduced.
Due to the action of ethylenediamine gradually penetrating into the gel filaments, covalent cross-linkages were formed between individual molecules of polyacrylic acid and highly swollen filament bundles which were water-insoluble were obtained. The length of the cross-linking bath is 18 feet, and the thread is passed back and forth through it by glass rolls at a rate of 90 feet per minute to obtain 1 for each 50-60 monomer unit of the polymer chain. Chemical cross-linking (crossing covalent bonds)
A cross-linked filament with .

After this treatment, the filament bundle was washed in a third bath of distilled water for about 3 minutes. The filament was then rolled up and dried with hot air. The overall cross-section of the fiber bundle was 160 denier, corresponding to about 4 denier per filament, an air dry tensile strength of 2.5 g/denier, and an elongation at break of 40%. These filaments do not lose their coherence and tensile properties when immersed in a bath of pure water at 25°C.
It was able to absorb up to 45% water by weight.

Example 2 The molecular weight of the acrylic acid polymer was increased to 300,000, the resulting gel filaments were conveyed at a reduced speed of 23 yards per minute over glass rolls in a spinning bath, and in a crosslinking bath. The process of Example 1 was repeated except that the speed was reduced from 90 feet per minute to 39 feet per minute and the filament was washed in a third bath of distilled water for 10 minutes.

The filament produced had the same properties as Example 1.

Example 3 A 22.5% solution of poly(hydroxyethyl methacrylate) having a molecular weight of 185,000 was prepared by dissolving the dry powdered polymer in water at 25°C. The solution was evacuated by keeping it at 40° C. for 24 hours in a vacuum container and delivered using a gear pump to a spinneret with 72 holes, each 0.080 mm in diameter. The solution was dissolved in 2.5% Na ₂ SO ₄ , 5%
It was extruded at a _rate of 60 feet per minute into an aqueous bath containing _MgSO4 and 2.5% _H2SO4 . Immediately after entering the bath, the filament solidified into a gel, which was stretched 1.25 times and kept in the bath for a distance of 12 feet while being passed back and forth on glass rolls. The coagulated filament is then
% MgSO ₄ and 5% oxalic acid. The temperature of this bath was maintained at 60°C. The filament moved at a speed of 12 feet per minute and over a total distance of 18 feet.

Under the influence of oxalic acid, cross-linking occurred and the filaments became covalently reticulated and became insoluble in aqueous systems.

When the filaments are dried after washing, they are 3.5 denier per filament and 2.8 denier per denier.
g and an elongation at break of 28%.

Yarns produced from these filaments are produced without losing any of their valuable textile properties.
It was able to absorb up to 38% moisture.

Example 4 Poly(hydroxyethyl methacrylate)
260,000, the extruded gel filament was moved through a coagulation bath by moving it back and forth over glass rolls while being stretched 1.25 times over a distance of approximately 40 feet, and sulfuric acid cross-linking. The filament is moved at approximately 12 m/s in a second bath containing magnesium sulfate and magnesium sulfate.
Example 3 was repeated except that it was moved over a distance of approximately 18 feet at a speed of 1.5 feet.

The filament produced had the same properties as Example 3.

Examples 5-8 Yarns were made by twisting 5 or 10% by weight of the fibers of Example 2 with polyethylene terephthalate fibers or nylon fibers and the yarn properties were measured. As a control, the properties of polyethylene terephthalate and nylon yarns without the addition of the hydrophilic fibers of the present invention were also measured. The results are shown in the table below.

Table 1 As can be seen from the examples above, the crosslinked hydrophilic fibers of the present invention possess remarkable physical properties in addition to their advantageous chemical and antistatic properties. For example, the specialty fibers of the present invention are characterized by a Young's modulus of at least 8 g per denier, and therefore these fibers can be
It can be blended with conventional textile fibers such as polyamide, acrylic, etc. without compromising the mechanical strength properties of fabrics made from these fiber blends.

Furthermore, while fabrics containing only 1 to 10% of the specialty fabric of the invention are particularly suitable for use in products such as clothing, bedding, and industrial fabrics, substantially greater amounts, such as at least 20% by weight,
Fabrics containing specialty fibers, especially at least 50% by weight, can be successfully used in applications where stress, stretching, etc. are not expected, for example as burn dressings where hydrophilicity is very important. .