JPH05311508A - Porous acrylonitrile-based yarn - Google Patents

Abstract

PURPOSE:To obtain porous AN-based yarn having excellently adsorbing and occluding function, to say nothing of excellent heat resistance, shape retention, water absorption and moisture absorption. CONSTITUTION:Undried yarn, obtained by wet spinning, of an AN-based polymer having >=95wt.% AN is subjected to wet heat treatment at 120-150 deg.C to give porous AN-based yarn wherein pores with a specific average pore diameter are connected and open on the surface of fibers. Since the yarn has the pores opening on the surface of the fibers and connected in the interior, the yarn exhibits absorbing, occluding and releasing function.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a porous acrylonitrile (hereinafter referred to as "AN") type fiber, more specifically, by adsorbing, occluding, etc. by allowing pores of a fiber having a porous structure to communicate with the fiber surface. AN with excellent heat resistance and shape retention that can be used as a device
It is related to the system fibers.

[0002]

2. Description of the Related Art Conventionally, various methods have been tried to obtain porous AN fibers. For example, Japanese Patent Publication Sho 60-11
No. 124 proposes to form a water-absorbing porous AN-based fiber by adding cellulose acetate to an AN spinning stock solution, but a spinning stock solution containing cellulose acetate contains an AN polymer alone. The stability and spinnability of the stock solution is inferior to that of the spinning stock solution, which is not industrially satisfactory, and the heat resistance of the spun yarn is reduced due to the modification of cellulose acetate, and the fiber is manufactured. It causes troubles during the process, and the quality of the product is not sufficient.

In Japanese Patent Publication No. 61-2005, a non-volatile solvent is added, dry spinning is performed, and then the solvent is extracted to form a water-absorbing porous AN fiber. However, in general, in the manufacturing process of AN fiber, the manufacturing cost is reduced by recovering the spinning solvent, but such a method imposes a great load on the recovery process of the solvent and is industrially sufficiently satisfactory. It is not something that will be done.

Furthermore, in JP-A-47-25416 and JP-B-48-8285, a swollen gel tow in a manufacturing process is filled with a water-soluble compound, dried and after-treated, the filled material is eluted. A method of regenerating the voids is described, and in JP-A-47-25418, a swollen gel tow is heat-moisture treated to leave fine voids,
All of them describe a method for imparting hygroscopicity to AN-based fibers, but this conventional means is extremely thermally non-existent in order to suppress the presence of voids as much as possible in order to satisfy the physical properties of the fibers and the dyeability of the fibers. It is stable, and in the treatment in boiling water, steaming treatment, ironing treatment, etc., there are serious quality deteriorations such as disappearance of voids and deterioration of shape retention of textiles. Further, such minute voids are not effective in that voids are likely to exist independently of each other, and it is difficult to form a structure that can form a passage between each void.

Furthermore, in Japanese Patent Laid-Open No. 63-309613, an organic liquid having a boiling point not higher than Tg of an undried standard wet-spun AN fiber and all water contained in the undried fiber are substantially contained. However, as described above, a large load is applied to the recovery of the solvent and an organic material having a low boiling point is used. The liquid recovery is not industrially advantageous.

As described above, although the porous AN-based fiber has been improved mainly for clothing, bedding and interior applications having a function of absorbing water and absorbing moisture, it is thermally stable and the fiber At present, it is not possible to obtain a porous AN-based fiber which is excellent in the shape retention of the product and is provided with a new function and which also satisfies the economical efficiency of the production method.

[0007]

DISCLOSURE OF THE INVENTION The object of the present invention is to provide the conventional method by allowing the pores of fibers having a porous structure to be thermally stable and have the shape-retaining property of the fiber product in communication with the fiber surface. The porous A that can be used not only as a water-absorbing function but also as a device for adsorption, storage, etc. and is industrially advantageous
It is to provide N-based fibers.

[0008]

The above-mentioned object of the present invention is to obtain an undried fiber after stretching obtained by wet spinning an acrylonitrile polymer containing 95% by weight or more of acrylonitrile as a bond, at 120 to 150 ° C. The micropores that are obtained by performing a heat treatment at a temperature of 1, and have a microporous structure have an average pore diameter of 100 to 6000Å, and the pores are connected and communicated with the fiber surface. It can be achieved by using a porous AN-based fiber.

Such a porous AN fiber of the present invention is
Since there are pores having an appropriate pore size in the fiber, each pore is connected inside the fiber, and because it does not have a skin layer, it communicates with the fiber surface, is thermally stable, and is a fiber product. Since it has the shape retention property, it can be used as a device for adsorption, occlusion, and the like.

The present invention will be described in detail below. In the porous AN fiber having a specific structure as described above, it is important to form an AN polymer containing 95% by weight or more of AN in the fiber structure. If the AN content of the AN polymer is less than 95% by weight, the pores will not be connected inside the fiber, and a skin layer will be formed on the fiber, which will not communicate with the fiber surface. Further, it becomes impossible to obtain a porous AN-based fiber that is thermally stable and achieves the initial purpose of obtaining the shape retention of the fiber product.

The AN polymer can be produced by a well-known polymerization means such as suspension polymerization method, emulsion polymerization method and solution polymerization method. Further, the polymer is a predetermined amount of AN.
And an unsaturated vinyl compound that is copolymerizable with AN. Examples of the unsaturated vinyl compound include acrylic acid, methacrylic acid or esters thereof such as methyl ester and ethyl ester; acrylamide, methacrylamide or N-alkyl substituted products thereof; vinyl esters such as vinyl acetate and vinyl propionate; Vinyl halides such as vinyl chloride, vinyl bromide, vinylidene chloride or vinylidene; unsaturated sulfonic acids such as vinyl sulfonic acid and p-styrene sulfonic acid or salts thereof; dimethylaminoethyl esters of acrylic acid and methacrylic acid; styrene Etc. can be used alone or in combination.

The polymer thus prepared is dissolved in an ordinary fiber solvent to form a stock solution for spinning, which is wet-spun by a known nozzle. In such spinning, it is difficult under ordinary spinning conditions to connect the respective pores inside the fiber and to communicate with the fiber surface, and it can be done by selecting the following means.

That is, to explain by using an example in which an inorganic salt such as sodium rhodanate is used as a solvent, the fiber spun from the nozzle as described above is 5 ° C to 15 ° C, preferably 5 ° C to 10 ° C.
Coagulation under the coagulation bath conditions, washing with water, stretching 7 to 15 times,
Further 120 ° C to 150 ° C, preferably 130 ° C to 15
A wet heat treatment is performed at 0 ° C., and then, drying is performed at 80 ° C. or higher to manufacture. If the coagulation bath temperature is less than 5 ° C., the initial purpose of obtaining a porous AN-based fiber in which the respective pores are connected inside the fiber and are connected to the fiber surface cannot be achieved. On the other hand, if it exceeds the upper limit, the spinnability is lowered, which is not preferable. When the draw ratio does not satisfy such a range, it is not preferable because problems such as failure to impart appropriate strength to the fiber and breakage of single yarn may occur.

On the other hand, if the temperature is lower than the lower limit of the moist heat treatment, a thermally stable fiber cannot be obtained and the temperature is 150 ° C.
In the above cases, the fiber form cannot be maintained and the invention cannot be achieved. In the drying conditions, if the temperature is lower than this value, it takes time to dry the fiber, which is not industrially advantageous. When an organic solvent is used, the coagulation bath temperature is 40 ° C or higher,
It is preferable to maintain the temperature at 50 ° C. or higher.

The average pore size of the pores according to the present application is 10
It is necessary to be 0 Å to 6000 Å, and if the lower limit is not satisfied, it is not possible to obtain an AN fiber having excellent heat resistance and capable of being used as a device for adsorption, occlusion, etc. and having shape retention. If the upper limit is not satisfied, fiber properties such as yarn breakage during spinning and strength of AN fiber cannot be obtained.

The pores of the porous fiber having the above-mentioned average pore diameter are not independent, but it is necessary that the respective pores be connected and communicate with the fiber surface. If these conditions are not satisfied, the pores of the fiber cannot be used as a device for adsorption, occlusion, etc., so only the fiber surface or only the vicinity of the fiber surface is used.

In particular, an AN-based polymer containing 95% by weight or more of AN bound thereto is wet-spun and drawn to obtain 12 undried fibers.
It is important to jointly adopt the condition of performing the wet heat treatment at a temperature of 0 to 150 ° C., preferably 130 to 150 ° C., and the porous AN-based fiber obtained by this is thermally stable and Not only does it have shape retention, but also has a microporous structure consisting of interconnected pores with a pore size of 100 to 6000Å that is in communication with the fiber surface, providing excellent adsorption and storage functions. It has a good commercial value because it has suitable fiber properties.

The following aspects can be mentioned as different embodiments of the present invention. That is, it is a means of introducing the following water-absorbent resin into the polymer component when the porous AN fiber is produced. Such water-absorbent resin means 1 to 15 per 400 polymer repeating units, preferably 2 to 10
It has a number of individual crosslinks, has a particle size of 0.5 μm or less, preferably 0.2 μm or less and a water swelling degree of 20 to 300 cc / g, preferably 30 to 150 cc / g in an absolutely dry state, and It is a resin that is insoluble in the solvent of the AN polymer.

The blending ratio of the water-absorbent resin is 1 to less than 6% by weight, preferably 1 to 5% by weight based on the weight of the AN polymer.
It can be selected from the range of% by weight. The water-absorbent resin may be introduced by mixing it into the polymer spinning stock solution so as to satisfy the above ratio. After spinning, the porous AN-based fiber is manufactured by adopting the above-mentioned means. The method for producing the water-absorbent resin is not particularly limited as long as the one satisfying the above-mentioned characteristics can be obtained. For example, the following method is advantageous in that a resin having such characteristics can be industrially advantageously produced. Can be mentioned.

That is, AN having a particle diameter of 0.5 μm or less, preferably 0.2 μm or less, and preferably 50% by weight or more, more preferably 70% by weight or more, based on the total amount of monomers constituting the polymer, 20 to 300 cc by introducing a carboxyl group into an aqueous dispersion of a crosslinked AN copolymer with a predetermined amount of a crosslinkable monomer and another vinyl monomer copolymerizable with AN by reacting an alkaline substance according to a conventional method
/ G, preferably a water-swelling resin having a water swelling degree of 30 to 150 cc / g or an aqueous dispersion of the resin can be industrially advantageously produced.

When such a water-absorbent resin is produced and used in the form of an aqueous dispersion, it is solidified into a jelly state in which the aqueous dispersion satisfies the following relational expression 1, so that it is previously treated with an alkali. It is preferable to keep the form of the water dispersion by avoiding shrinkage and solidification of the water-absorbent resin by means such as coexistence of a water-miscible organic solvent or electrolyte salt in the medium.

[0022]

[Equation 1]

However, C: water-absorbent resin concentration in the water dispersion (wt%) S: water swelling degree of the water-absorbent resin (cc / g) W: ratio of water in the water dispersion (wt%)

Examples of the crosslinkable monomer include acrylic acid or methacrylic acid diesters, triesters or tetraesters, unsaturated carboxylic acid allyl esters, polycarboxylic acid diallyl esters, and divinyl. Crosslinkable monomers having two or more double bonds copolymerizable in the molecule such as acid anhydrides, divinylsulfone, methylenebisacrylamide, or divinylbenzene and its alkyl- or halogen-substituted compounds, and / or the above-mentioned non-crosslinkable monomers. Examples thereof include glycidyl esters of saturated carboxylic acids or unsaturated sulfonic acids, and crosslinkable monomers having at least one epoxy group in the molecule such as unsaturated glycidyl ethers.

The above-exemplified crosslinkable monomer can be used as the above-mentioned copolymerization component to crosslink at the time of polymerization or after the completion of the polymerization, whereby the purpose of easily producing a crosslinked AN copolymer can be achieved. Among them, divinyl sulfone, methylenebisacrylamide, which has two or more double bonds that can be copolymerized in the molecule and has high alkali resistance,
It is desirable to use a crosslinkable monomer such as divinylbenzene as a copolymerization component. The method for producing the crosslinked AN-based copolymer having the above-mentioned fine particle diameter can be advantageously carried out, for example, by adopting the invention of Japanese Patent No. 1009923 of the present applicant.

By using a resin in which a crosslinked AN-type copolymer coexists as a component as such a water-absorbent resin, the miscibility with the fiber-forming matrix polymer (AN-type polymer) or the spinnability is further improved. It is desirable because it will be done.

The porous AN-based fiber thus obtained by introducing the water-absorbing resin is as thermally stable as the above-described porous AN-based fiber not containing the water-absorbing resin and has the shape retention property of the fiber product. In addition, the pores of the fiber having a microporous structure have micro and macro pores, each pore is connected inside the fiber and communicates with the surface of the fiber, and it has excellent water absorption as well as excellent adsorption. Since it has an occlusion function and has appropriate fiber physical properties, it has a good commercial value.

[0028]

In the porous AN fiber according to the present application, the microporous structure is more positively formed inside the fiber during the solidification process of forming the fiber by wet spinning. The pores that form the basis of the structure become micro and macro due to the effect of the AN content of the AN polymer and the wet heat treatment condition of the undried fiber after spinning, and the individual pores are connected to reach the fiber surface. ing. The peculiarities of the base material and the structure may express the various properties and functions of the fiber of the present invention.

[0029]

EXAMPLES Examples will be shown below for facilitating the understanding of the present invention, but these are merely examples, and the gist of the present invention is not limited thereto. In the examples, parts and percentages are by weight unless otherwise specified. The pore size described in the examples is measured by the following method. (1) Pore size Shimadzu-Micromeritics Poisizer 931
Form 0 was used to measure the pore size in the fiber.

[0030]

【Example】

[1] As shown in Table 1, AN, methyl acrylate (M
A) and sodium methallyl sulfonate (MAS) were used, and AN-based polymers prepared by changing the polymer composition were used, and each was dissolved in an aqueous solution of sodium rhodanate to prepare a spinning dope. Wet spinning was performed using these spinning dope solutions to prepare 6 types of AN fibers. That is, coagulation is performed in a 12% sodium rhodanate aqueous solution at 5 ° C., followed by washing with water and 10 times stretching, and the resulting undried fiber is
Wet heat treatment was performed using steam under conditions of ℃ × 10 minutes, and further dried at 100 ℃ for 20 minutes to obtain a sample fiber. The performance of each AN fiber is shown in Table 1.

For the transparency in the table, dimethyl phthalate was added with ethyl alcohol, and the fiber was dipped in a liquid whose refractive index was adjusted to 1.506 (the same refractive index as that of acrylic fiber) to observe the transparent state with the naked eye. It is the result of carrying out (if the inside of the fiber is densified or the pores in the fiber communicate with the surface, it looks transparent, and if the pores in the fiber do not communicate with the surface, the solution becomes cloudy. In the transparency column in the table, the ◯ mark indicates transparent, and the X mark indicates cloudy.)

The dye adsorption state was 1000 pp using Crystal Violet Blue manufactured by Maeda Kasei Co.
m to prepare a solution, and add the fiber to the solution at room temperature (20 ° C) for 30
It is the result of observing the adsorption state of the dye by immersing it for a minute with a microscope (when the pores in the fiber do not communicate with the surface, the dye does not penetrate into the fiber. The fact that the dye has penetrated into the fiber, the mark X indicates that it has not penetrated. The dye adsorption state for the nonwoven fabric described later has the same meaning.).

[0033]

[Table 1]

Sample No. which satisfies the present invention It is understood that 4 to 6 have an appropriate average pore diameter, and the pores are connected and communicate with the fiber surface.

Then, using the above-mentioned 6 kinds of fibers and the heat fusion fiber Melty Type-110 (manufactured by Unitika Ltd.),
Six kinds of heat-bonded nonwoven fabrics were produced at a mixing ratio of porous AN fiber / heat-bonded fiber = 40/60 at 150 ° C. for 5 minutes. The prepared non-woven fabric was immersed in a crystal violet blue dyeing solution in the same manner as described above, and the dye adsorption state was observed. The results are shown in Table 2 below.

[0036]

[Table 2]

As shown in Table 2, if 95% by weight or more of AN of the present invention is bound and contained, and the wet heat treatment conditions do not satisfy the recommended conditions, the pore morphology is also changed by the formation of specific pores or heat load. It is understood that the pores are not crushed and have thermal stability, and the intended porous AN fiber cannot be obtained.

[0038]

【Example】

[2] No. manufactured in Example 1 After the following 5 kinds of fibers were obtained in the same manner as in Example 1 except that the wet heat treatment conditions were changed as shown in Table 3 below using the polymer of Example 5, 5 kinds of heat-bonded nonwoven fabrics were obtained in the same manner as in Example 1. Was produced. The evaluation results are also shown in Table 3 below.

[0039]

[Table 3]

As shown in Table 3, as in Example 1, if 95% by weight or more of AN of the present invention was bound and contained and the wet heat treatment conditions also did not satisfy the recommended conditions, fiber pore formation and thermal stability were obtained. It can be clearly seen that the porous AN-based fibers to which the above-mentioned is added cannot be obtained.

[0041]

[Comparative example]

[1] Normal AN fiber (K8 manufactured by Exlan Co., Ltd.)
3d × 51 mm) and the same experiment as in Example 1 was conducted for comparison. The results are shown in Table 4 below.

[0042]

[Table 4]

As shown in Table 4, the result of the transparency of the usual AN fiber is the above result because the fiber is densified (there are no pores in the fiber), but the dye adsorption is not observed at all. This is not done and, of course, there is no communication of the pores with the fiber surface, which naturally does not satisfy the present invention.

[0044]

【Example】

[3] When performing the spinning of this example, the spinning solution was sample No. 1 of Example 1. A water-absorbent resin aqueous dispersion prepared by the following method (sodium rhodanate is added so that the viscosity becomes 100 centipoise) was added to the polymer spinning stock solution of 5 to make the water-absorbent resin 3% based on the weight of the polymer. What was added in this way was used. The water-absorbent resin fine particles did not aggregate in the spinning dope, and no problems such as nozzle clogging and yarn breakage occurred during spinning. After spinning, the same method as in Example 1 was adopted to produce a porous AN fiber.

The fiber thus obtained has pores having an average pore diameter of 5300Å and has a fiber strength of 2.55 (g / d).
In addition, it was shown that the porous AN-based fiber had no problem in transparency, had sufficient dye adsorption before and after preparation of the nonwoven fabric, and was thermally stable.

The water absorbent resin used above was prepared as follows. That is, AN76 part, MA20
, 2 parts of methylenebisacrylamide (MBA) and 2 parts of p-sodium styrenesulfonate (SpSS) and 233 parts of water were charged into a 2 liter autoclave, and tert-butyl peroxide was used as a polymerization initiator. Add 0.5% to the total amount and then seal,
Then, the mixture was polymerized under stirring at 150 ° C for 20 minutes. After completion of the reaction, the product was taken out from the autoclave after cooling to about 90 ° C. while continuing stirring. The particle size of the polymer dispersed in this crosslinked AN copolymer emulsion is 0.1.
It was μ.

Next, 20 parts of the emulsion having the polymer concentration adjusted to 25% was added to 80 parts of a 3% aqueous solution of caustic soda, and subjected to alkali treatment at 95 ° C. for 30 minutes while stirring. The water absorbent resin thus obtained had a crosslinked AN-based copolymer core and had a particle diameter of 0.1 μ and a water swelling degree of 70 cc / g.

The water swelling degree is measured and calculated by the following method. About 0.5 g of the water-absorbent resin is immersed in pure water, and after 24 hours at 25 ° C., the water-swelled water-absorbent resin is sandwiched between filter papers to remove water between resin particles. The weight (W1) of the sample thus adjusted is measured. Next, the sample is dried in a vacuum dryer at 80 ° C. to a constant weight, and the weight (W2) is measured. From the above measurement results, it is calculated according to the following mathematical formula 2.

[0049]

[Equation 2]

[0050]

Industrial Applicability The porous AN fiber obtained by the present invention is thermally stable and excellent in the shape retention of the fiber product, and the pores of the fiber having the porous structure are 100 to 60.
00Å communicates with the fiber surface and has excellent absorption and storage functions as well as water absorption. It is possible to impregnate and carry various chemicals such as insecticides, antibacterial agents and soil conditioners. It can also be applied as a device such as an agent or a catalyst carrier.

Claims (1)

[Claims] 1. An undried fiber obtained by wet-spinning an acrylonitrile-based polymer containing 95% by weight or more of acrylonitrile as a bond is obtained by subjecting it to wet heat treatment at a temperature of 120 to 150 ° C. Porous acrylonitrile fiber characterized in that the pores forming the porous structure have an average pore diameter of 100 to 6000Å, and the pores are connected and communicate with the fiber surface.