JPS648084B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is a novel water-absorbing acrylonitrile (hereinafter referred to as
It is about AN) based fibers, and more specifically, two types of AN based polymers with different AN contents are used, and the polymer component with a high AN content exhibits a microporous structure, and Composite with excellent water absorption and good mechanical strength, with small polymer components exhibiting a dense structure.
This relates to AN-based fibers. It is well known that AN-based fibers exhibit excellent properties in terms of heat retention, shrinkage, shape stability, weather resistance, texture, dyeability, etc., and are used in large quantities for clothing and interior decoration. That's where it happened. However, such AN-based fibers are not completely free from practical limitations, and there are several problems that require urgent measures to be taken. For example, AN-based fibers have poor water absorption and hygroscopicity, and when used in underwear, sportswear, towels, etc., they are used in blends with natural fibers such as cotton and hemp, or cellulose fibers. In order to improve the water absorption and hygroscopic properties of such AN-based fibers, many prototypes and trials have been made so far. For example, attempts have been made to make fibers porous and impart water-absorbing properties by copolymerizing them with hydrophilic substances or by using foaming agents, etc., but none of these methods have sufficient water-absorbing properties, and This caused a decrease in performance. In addition, in obtaining acrylic synthetic fibers consisting of a single component through wet spinning, the present inventors created pores uniformly in the fiber structure during the manufacturing process, and left them in the final fibers to impart water absorption properties. However, although the resulting fibers maintain a certain degree of water absorption, they have the disadvantage that mechanical properties (strength, elongation) are significantly reduced, leading to major troubles during processing stages such as spinning. I admitted something. Under these circumstances, the present inventors conducted further research to eliminate the above-mentioned drawbacks, and as a result, the composite AN-based fiber, in which one part has a microporous structure and the other part has a dense structure, overcomes the above-mentioned drawbacks. We have discovered the facts that can solve all the problems and have arrived at the present invention. That is, an object of the present invention is to provide a novel composite AN fiber having excellent water absorption performance and satisfactory mechanical properties. Another object of the present invention is to provide a composite AN fiber suitable as a material for underwear, sportswear, towels, etc. Other objects of the present invention will become apparent from the following description. The above-mentioned object of the present invention is to produce an AN-based polymer (20 to 10 parts by weight) containing 90% by weight or more of AN in combination and an AN-based polymer (20 to 10 parts by weight) containing 88% by weight or less of AN in combination.
90 parts by weight, and the polymer () component has a microporous structure, and the polymer () component has a microporous structure.
This can be achieved by using water-absorbing AN fibers in which each of the components is formed into a dense structure, has a knot strength of 1.5 g/d or more, a dry elongation of 30% or more, and a water retention rate of 20% or more. In the composite AN fiber obtained by the present invention, a large number of micropores exist in the polymer component containing 90% by weight or more of AN, and a dense structure is introduced in the polymer component containing 88% by weight or less. Therefore, it satisfies water absorbency and mechanical properties at the same time. What is even more surprising is that there is no skin layer in the porous part, and the micropores maintain an appropriate particle size and exhibit capillary behavior, which has the ability to instantly absorb water. becomes. In addition, the moisture that is instantly absorbed is released to the outside through the voids inside the fibers, and this release rate is faster than that of cotton, giving less sticky feeling when worn and providing a dry and comfortable feel. In water-absorbing AN-based fibers having the above-mentioned unique structure, an AN-based polymer () containing 90% by weight or more of AN and 88% by weight or less of AN
It is important to use the AN polymer () as both components and to form the polymer () component into a microporous structure and the polymer () component into a dense structure. When the AN content of the polymer () is less than 90% by weight and when the AN content of the polymer () is 88
If it exceeds the weight percentage, the polymer () component is formed into a microporous structure to exhibit excellent water absorption performance, and at the same time, the polymer () component is formed into a dense structure to achieve satisfactory mechanical properties. It is not possible to obtain a composite AN-based fiber that achieves the desired purpose of finally having both water absorption performance and mechanical properties. Both polymer components can be arbitrarily selected from composite types (for example, side-by-side type, sheath-core type, random type), but it is preferable to adopt side-by-side type or sheath-core type to advantageously achieve the object of the present invention. can be achieved. Moreover, the above-mentioned polymers () and () can be produced by well-known polymerization methods (suspension polymerization method, emulsion polymerization method, solution polymerization method, etc.). Each of these polymers is produced by copolymerizing a predetermined amount of AN and an unsaturated vinyl compound that can be copolymerized with AN. Such unsaturated vinyl compounds include:
Acrylic acid, methacrylic acid or esters such as methyl esters and ethyl esters; acrylamide, methacrylamide or N-alkyl substituted products thereof; vinyl esters such as vinyl acetate and vinyl propionate; vinyl chloride, vinyl bromide, Vinyl halides or vinylidenes such as vinylidene chloride; Unsaturated sulfonic acids or salts thereof such as vinyl sulfonic acid and p-styrene sulfonic acid; Dimethylaminoethyl ester of acrylic acid and methacrylic acid; styrene, etc. alone or in combination Can be used. The polymer () or polymer () produced in this way is dissolved in a common fiber solvent to form a spinning dope, which is then spun through a known nozzle. Composite spinning is used as the spinning means in this case, but
Among these, side-by-side type or sheath core type composite spinning is recommended. Composite ratio (abundance ratio) of polymer ()/polymer () in such composite spinning
can be selected from the range of 80/20 to 10/90. Outside this range, problems such as insufficient water absorption performance and no improvement in mechanical strength may occur. Although spinning is performed in this manner, formation of a heterogeneous structure between both polymer components is difficult under normal wet spinning conditions, and can be achieved by selecting the following means. That is, when an inorganic salt such as sodium rhodanate is used as a solvent, the fibers spun as described above are heated at 3°C to
Solidified at 15℃, washed with water, hot stretched, and then
It is produced by moist heat treatment at 100°C to 120°C and drying at 80°C to 130°C. If the coagulation bath temperature is less than 3°C, a microporous structure will not be formed in the AN polymer (), and if it exceeds 15°C, the spinnability will deteriorate, which is undesirable. On the other hand, the drying temperature
If the temperature is less than 80°C, productivity will decrease, and if it exceeds 130°C, micropores may disappear, which is not desirable. Note that the moist heat treatment includes steam treatment, boiling water treatment, and the like. Furthermore, when using an organic solvent, it is desirable to maintain the coagulation bath temperature at 40°C or higher, preferably at 50°C or higher. The composite AN-based fiber obtained in this way has excellent water absorption performance and is suitable for spinning, etc., because it has a part with many micropores and a dense part integrated into the fiber structure. It also has good processability and is rich in commercial value. Further, as described above, the composite AN fiber according to the present invention also has the ability to instantly absorb water, so it greatly increases consumption performance. Further, the following points can be mentioned as different embodiments of the present invention. That is, when producing the AN-based fiber, the following water-absorbing resin can be introduced into the polymer () and/or the polymer () component. Such water-absorbing resin is 1 to 15 per 400 polymer repeating units,
It preferably has 2 to 10 crosslinks, has a particle size of 0.5μ or less, preferably 0.2μ or less in an absolutely dry state, and has a particle size of 20μ or less.
The resin has a water swelling degree of ~300 c.c./g, preferably 30 to 150 c.c./g, and is insoluble in water and the solvent of the AN polymer. The blending ratio of the water-absorbing resin can be selected from the range of 1 to less than 6% by weight, preferably 1 to 5% by weight based on the weight of the polymer () and/or the polymer (). The introduction of such a water-absorbing resin is
What is necessary is just to add and mix to polymer () and/or polymer () spinning stock solution so that the above-mentioned ratio may be satisfied.
However, when introducing a water-absorbing resin into the polymer, it is wise to include it within a range that does not impair the mechanical properties of the fibers. After spinning, the water-absorbent resin-containing AN-based fibers are manufactured using the above-described methods. The method for producing such a water-absorbing resin is not limited in any way as long as it satisfies the above-mentioned properties; can be mentioned. That is, the particle size is 0.5μ or less, preferably 0.2μ or less, and preferably 50% by weight or more, more preferably 70% by weight based on the total amount of monomers constituting the polymer.
of AN, a predetermined amount of crosslinking monomer and AN
Crosslinked AN with other vinyl monomers that can be copolymerized with
20 to 300 c.c./g, preferably 30 to 150 c.c./g, by introducing carboxyl groups into a copolymer or an aqueous dispersion of the polymer by reacting an alkali substance according to a conventional method. It is possible to produce a resin having a water swelling degree of g or an aqueous dispersion of the resin with industrial advantage. In addition, when producing and using such a water-absorbing resin in the form of an aqueous dispersion, the entire aqueous dispersion solidifies into a jelly-like form when the aqueous dispersion has the following relational expression (), so it must be treated with an alkali in advance. It is preferable to shrink the resin and maintain the form of an aqueous dispersion by coexisting a water-miscible organic solvent or an electrolyte salt in the medium. C×S=W (1) However, C: Water-absorbing resin concentration in the water dispersion (wt%) S: Water swelling degree of the water-absorbing resin (cc/g) W: Ratio of water in the water dispersion ( Weight%) The crosslinking monomers mentioned above include, for example, diesters of acrylic acid or methacrylic acid,
Triesters or tetraesters, allyl esters of unsaturated carboxylic acids, diallyl esters of polyvalent carboxylic acids, divinyl acid anhydrides, divinyl sulfone, methylenebisacrylamide, or divinylbenzene and its alkyl or halogen Crosslinkable monomers having two or more copolymerizable double bonds in the molecule, such as substituents, and/or glycidyl esters and unsaturated glycidyl ethers of the above-mentioned unsaturated carboxylic acids or unsaturated sulfonic acids. This can be easily achieved by using a crosslinkable monomer having at least one epoxy group as the copolymerization component to effect crosslinking during or after the polymerization. It is desirable to use crosslinkable monomers such as divinylsulfone, methylenebisacrylamide, and divinylbenzene, which have two or more double bonds and have high alkali resistance, as copolymerization components. In addition, cross-linked AN with the above fine particle size
The method for producing the copolymer can be advantageously carried out by employing, for example, the invention of Japanese Patent Application No. 51-24334 filed by the present applicant. In addition, by using a resin in which a crosslinked AN-based copolymer coexists as the water-absorbing resin, miscibility with the fiber-forming matrix polymer (AN-based polymer), stringability, etc. are further improved. Therefore, it is desirable. The method for producing a water-absorbing resin in which such a crosslinked AN copolymer coexists is not limited in any way, but for example, by selecting the vinyl monomer constituting the crosslinked AN copolymer or adjusting the hydrolysis conditions. Only the surface layer part of the crosslinked AN copolymer particles is partially hydrolyzed to leave an unreacted core part of the copolymer, or the resin particles remaining in the core part are further processed by a colloid mill, a ball mill, etc. It can be advantageously produced by a method such as grinding to expose at least a part of the crosslinked AN copolymer on the surface of the water absorbent resin. Composite AN made by introducing water-absorbing resin in this way
The fibers are composite fibers that do not contain the water-absorbing resin described above.
Like AN-based fibers, it has improved water-absorbing performance and mechanical properties, and also has high instantaneous water-absorbing ability. The water-absorbing AN-based fiber of the present invention produced as described above can be used alone or in combination with commercially available synthetic fibers such as polyester, polyamide, polyacrylic, or modacrylic, cotton, wool, etc. The company provides comfortable underwear, sportswear, towels, etc. The present invention will be explained in more detail with reference to Examples below. In the examples, parts and percentages are expressed on a weight basis unless otherwise specified. Note that the water retention rates described in the Examples were measured and calculated by the following method. (1) Water retention rate Approximately 1 g of sample fiber, cut into a length of approximately 5 cm and well opened, is immersed in pure water for 20 minutes (25°C).
After the time has passed, water in the gaps between the fibers is removed using a centrifugal dehydrator (manufactured by Kokusan Enshinki Co., Ltd., radius 12 cm) at a rotation speed of 2000 rpm. The weight (W ₁ ) of the sample thus prepared is measured. Next, the sample is dried in a vacuum dryer at 80° C. until it reaches a constant weight, and the weight (W ₂ ) is measured. Calculate the water retention rate using the following formula. Water retention rate = W ₁ - W ₂ / W ₂ × 100 (%) Example 1 AN copolymer () consisting of 91% AN, 8.7% methyl acrylate (MA), and 0.3% sodium methallylsulfonate (MAS) AN87%, MA12.7% and
AN copolymer (2) consisting of 0.3% MAS was dissolved in an aqueous solution of sodium rhodanate to prepare two types of spinning stock solutions. Using these spinning stock solutions, (i) each individual spinning (ii) polymer (); polymer () = 1:1
Composite spinning (spinning equipment was manufactured by the Special Publication Corporation in 1977)
11122)) and three types of AN
A fiber based on this method was produced. Coagulation was performed in a 12% sodium rhodanate aqueous solution at 10°C, followed by water washing and hot stretching, and the resulting fibers were stretched in a relaxed state without drying.
Steam treatment at 115°C, then 15°C at 100°C.
It was prepared by drying for minutes. When the cross section of the obtained No. 3 fiber was observed under a microscope, it was found that there were many micropores on the polymer () component side, whereas the polymer () component side had a completely dense structure. Ta. The fiber performance of each AN-based fiber is listed in Table 1.

[Table] From the results in Table 1, it can be seen that the AN-based fiber (No. 3) according to the present invention is a product with excellent water absorption capacity, strength and elongation, and has high commercial value. Good water retention capacity requires a water retention rate of 20% or more, knot strength of 1.5 g/d or more, and dry elongation.
If it is not 30% or more, problems will occur during processing such as spinning. Furthermore, when the underwear made from No. 3 composite AN fiber came into contact with water, it instantly absorbed the water, and after a while it regained a smooth feel. Example 2 The polymer composition was varied as shown in Table 2.
Composite spinning was carried out in the same manner as in Example 1 except that AN polymer was used to obtain AN fiber. The results of measuring the fiber capacity and mechanical strength of the obtained fibers are also listed in Table 2.

[Table] As is clear from Table 2, it is easily understood that the AN-based fibers (Nos. 4 and 5) according to the present invention are excellent in water absorption performance and mechanical properties. The dry elongation (%) of the composite AN fibers No. 4 and No. 5 were good at 36 and 43, respectively. Example 3 AN-based fibers were produced in the same manner as in Example 1 except that the composite ratios of Polymer () and Polymer () used in Example 1 were varied as shown in Table 3.
The evaluation of the obtained fibers is also shown in Table 3.

[Table] From the results in Table 3, when producing composite AN fibers (Nos. 9 to 11) according to the present invention, by selecting a predetermined composite ratio, good water absorption and mechanical properties can be achieved. It is understood that this can be obtained.
In addition, the dry elongation (%) of the fibers No. 9 to 11 above are as follows:
The values were 45, 40 and 34, respectively, which were good. Example 4 When performing the composite spinning of Example 1, a water-absorbing resin water dispersion (added with sodium rhodanate to give a viscosity of 100 centipoise) prepared by the following method was added to the polymer () spinning stock solution. The water absorbent resin was added in an amount of 3% based on the combined weight.
The water-absorbing resin fine particles did not aggregate in the spinning dope, and no problems such as nozzle clogging or yarn breakage occurred during spinning. Example 1 after spinning
A final fiber (No. 14) was prepared using the same method as above. The composite AN fiber thus obtained had a water retention rate of 50%, a binding strength of 1.9 g/d, and a dry elongation of 43%. Furthermore, even when summer clothing made by mixing this fiber was washed and ironed, its water retention properties did not decrease. The water absorbent resin used above was produced as follows. That is, 76 parts of AN, 20 parts of MA, 2 parts of methylenebisacrylamide (MBA), 2 parts of sodium p-styrene sulfonate (SpSS), and 233 parts of water were charged into the autoclave No. 2, and di-tert-butyl was added as a polymerization initiator. After adding 0.5% peroxide based on the total amount of monomers, the reactor was sealed and polymerized at 150° C. for 20 minutes with stirring. After the reaction was completed, the product was cooled to about 90°C while stirring, and then taken out from the autoclave. The particle size of the polymer dispersed in this crosslinked AN copolymer emulsion (a) was 0.1 μ. Next, 20 parts of the above emulsion (a) whose polymer concentration was adjusted to 25% was added to 80 parts of a 3% aqueous solution of caustic soda, and an alkali treatment was performed at 95° C. for 30 minutes while stirring. The obtained water absorbent resin (A) has a crosslinked AN copolymer core, has a particle size of 0.1μ, and has a particle size of 70c.c./g.
It had a degree of water swelling of . The above water swelling degree was measured and calculated by the following method. Approximately 0.5g of water-absorbent resin was immersed in pure water and heated at 25℃ for 24 hours.
After a period of time has elapsed, the water-swollen water absorbent resin is sandwiched between pieces of paper to remove water between the resin particles. The weight (W ₁ ) of the sample thus prepared is measured. Next, the sample is dried in a vacuum dryer at 80° C. until it reaches a constant weight, and the weight (W ₂ ) is measured. From the above measurement results, it is calculated according to the following formula. Water swelling degree (cc/g) = W ₁ − W ₂ /W ₂

Claims (1)

[Claims] 1 A composite of 80 to 10 parts by weight of an acrylonitrile polymer () containing 90% by weight or more of acrylonitrile in combination and 20 to 90 parts by weight of an acrylonitrile polymer () containing 88% by weight or less of acrylonitrile in combination. , and the polymer () component is formed into a microporous structure, and the polymer () component is formed into a dense structure, and has a knot strength of 1.5 g/d or more, a dry elongation of 30% or more, and water retention. Rate is
Acrylonitrile fiber with water absorption of 20% or more.