KR100475423B1 - Absorbent acrylic fiber - Google Patents

Abstract

(Objective) To provide absorbent acrylic fibers having good heat resistance, shape retaining properties and crimp stability, and which can be processed after the same as conventional acrylic fibers.

(Structure) The acrylonitrile polymer containing at least 85% by weight of acrylonitrile units and cellulose were dissolved in an aqueous thiocyanate solution, and 80 to 95% by weight of the acrylonitrile polymer and 20 to 5% by weight of cellulose were mixed. Absorbent acrylic fiber obtained by containing a macrovoid without being lost by heat treatment, such as drying and crimp set by wet spinning.

(Effect) The heat treatment of drying, crimp set, etc. is possible, and the heat resistance, shape retaining property and crimp stability are good, and it can be used without comparable with conventional acrylic fibers.

Description

Absorbent Acrylic Fiber {ABSORBENT ACRYLIC FIBER}

The present invention relates to an absorbent acrylic fiber used in clothing, interior, industrial materials.

Natural fibers such as cotton and wool exhibit high absorption of 20 to 40% by weight, but general synthetic fibers lack absorbency and have a lower commodity value than natural fibers. In order to improve the absorption performance of synthetic fibers, many studies have been made in the past. Among them, many fibers have been proposed using the capillary phenomenon as the fibers have a porous structure.

For example, Japanese Patent Application Laid-Open No. 47-25418, No. 47-15901, No. 48-6649 and No. 48-6650 disclose microscopic voids or microsized in swollen gel toe in an acrylic fiber manufacturing process. A method for producing porous acrylic fibers is described by selecting mild drying conditions to leave voids. Alternatively, Japanese Patent Application Laid-Open Nos. 47-25416, 48-8285, and 48-8286 disclose a swelling gel tow in the process of producing acrylic fibers, and a water-soluble compound is filled, and the filler is dried and post-treated. Elution to regenerate the voids is described.

What is common to the above method is a technique for producing porous acrylic fibers in which the microvoids originally contained in the swelling gel-toe during the production process of the acrylic fibers remain in the final product.

However, the microvoids contained in the swelling gel tow are extremely unstable in the fiber manufacturing process because they are extremely unstable thermally, and therefore, the high temperature treatment cannot be performed particularly in the fiber manufacturing process, particularly in the drying and crimp sets. The product's heat resistance, formability and crimp stability are lacking, causing a significant decrease in the product value of the product. However, the reality is that absorptive acrylic fibers excluding such causes have not been achieved yet.

In such a situation, the present inventors have studied diligently to solve the above problems, and as a result, the acrylonitrile-based polymer and cellulose were dissolved together in an aqueous thiocyanate solution, made into a spinning stock solution, and wet spinning was performed. It has been found that this is achieved by retaining the microvoids that occur on the basis of tea in acrylic fibers. That is, this invention consists of a mixture of 80-95 weight% of acrylonitrile-type polymers containing 20 to 5 weight% of celluloses containing an acrylonitrile unit of at least 85 weight%, and the water absorption is 20 weight% or more. A water absorbent acrylic fiber characterized by the above-mentioned.

Hereinafter, the present invention will be described in detail.

As an acrylonitrile-type polymer which is a raw material of the acrylic fiber employ | adopted for this invention, if an acrylonitrile ratio is 85 weight% or more, there will be no restriction | limiting in particular, A homopolymer and a copolymer with a well-known monomer can be used. When the acrylonitrile (hereinafter also referred to as AN) ratio is less than 85% by weight, the thermal stability of the acrylic fiber is remarkably lowered, and the quality of the final product is sometimes lowered for easy coloring.

The comonomer used for the copolymerization is not particularly limited as long as it is copolymerized with acrylonitrile such as other polymerizable unsaturated vinyl compounds, and for example, alkyl acrylate, alkyl methacrylate, acrylic acid, methacrylic acid, methacrylonitrile and acrylamide. , Vinyl acetate, vinyl chloride, vinyl bromide, fluorovinyl, vinyl alkylate, vinylidene chloride, vinylidene bromide, styrene, styrenesulfonic acid, allylsulfonic acid, metalylsulfonic acid, styrenesulfonic acid salts, allylsulfonic acid salts, metalylsulfonic acid salts , Ethylene, propylene and the like can be used.

Although the cellulose used for this invention is not specifically limited, In the solubility to the thiocyanate aqueous solution, it is the amorphous cellulose which pretreated in order to disturb the crystal structure in cellulose previously, and the thing of average polymerization degree 50-500 is preferable.

The AN-based polymer and cellulose thus produced are dissolved in a thiocyanate aqueous solution as a solvent to form a spinning stock solution, and wet-spun with a known nozzle. As thiocyanate, calcium thiocyanate, magnesium thiocyanate, lithium thiocyanate, strontium thiocyanate, and sodium thiocyanate are used preferably.

The addition amount of cellulose is 5-20 weight% of the polymer total amount, and 7-15 weight% is preferable. If the amount of cellulose added is less than 5% by weight, the water absorption is low. If the amount of cellulose is more than 20% by weight, the water absorption increases.

The absorptive acrylic fiber of this invention is obtained by mixing the said polymer in the state which the spun fiber had the multilayer structure of an acrylonitrile-type polymer and cellulose in the short fiber, and wet spinning. As the spinning method, any of conventional wet spinning and dry wet spinning can be preferably employed. The solution is discharged into a thiocyanate / aqueous solution as a coagulation solution, stepwise desolvated and washed with water, followed by stretching 7 to 12 times, followed by drying and densification, followed by crimping and crimping.

Although crimp set is performed on 120-150 degreeC and the conditions for 10 second-15 minutes, More preferably, 125-140 degreeC is good. The rate of absorption increases rapidly at 125 ° C, but the fibers sometimes get stuck if the treatment temperature is too high. The treatment time is preferably shorter at higher temperature, but is preferably 15 seconds or more in order to avoid shrinkage stains and staining stains. In addition, the water absorption was measured by the following method. 10 g of the fiber was opened, wrapped in gauze, washed in a activator (NEIGEN HC 1 mL / 1 L) at 60 ° C. for 30 minutes, and then washed with running water and dewatered. Subsequently, the solution was dehydrated in deionized water for 30 minutes, washed with running water, and dewatered. After drying at 110 ° C. for 20 minutes, it was immersed in ion-exchanged water adjusted to 30 ° C. and left for 3 hours. The centrifugal dehydrator (TYPE H-770A manufactured by Kogusan Centrifuge Co., Ltd.) was dehydrated for 3 minutes at a scale of 3, and the fibers were removed from the gauze and weighed. Next, it weighed after drying for 30 minutes at 90 degreeC. Absorption rate says what was computed by Formula 1.

(Action)

The present invention is a macrovoid in the fiber by wet spinning a mixed polymer solution obtained by dissolving an acrylonitrile-based polymer of different coagulation properties and two kinds of polymers called cellulose in a thiocyanate solution, which is a common solvent. The acrylonitrile-based polymer alone causes the voids lost by drying or crimp set to remain after heat treatment due to the heat resistance of water and cellulose retained in the voids by cellulose hydrophilicity, thereby absorbing the capillary phenomenon. To give.

(Example)

Although an Example is shown to facilitate understanding of this invention below, these are only illustrations and the summary of this invention is not limited by these.

In addition, in an Example, a part and a 100 fraction are shown on a basis of weight unless there is a notice in particular.

Example 1

A mixture of acrylonitrile-based polymer obtained by polymerizing acrylonitrile and methyl acrylate in a ratio of 90% by weight to 10% by weight with cellulose having a degree of polymerization of 200 was mixed at a ratio of 96/4 to 65/35, which was 60% by weight. It was dissolved in an aqueous solution of calcium thiocyanate to prepare a spinning stock solution having a polymer concentration of 15%. The solution was wet-spun with 25 ° C. and 15% by weight aqueous calcium thiocyanate solution as a coagulant solution, washed with water, 10 times hot stretching, dried at 130 ° C. with a heating roller under tension, and densified. Wet-heat treatment was performed and five kinds of acrylic fiber samples were obtained. (Samples No. 1 to 5) Absorption rate and tensile strength are shown in Table 1.

No. Acrylonitrile-Based Polymers / Cellulose Water absorption The tensile strength Elongation Yarn, elongation One 96/4 18% 3.5 g / d 35% none 2 95/5 22% 3.3 g / d 33% none 3 80/20 30% 2.9 g / d 30% none 4 70/30 35% 2.2 g / d 20% has exist 5 65/35 38% 0.9 g / d 12% has exist

Fibers having a cellulose content of 4% by weight or less are subjected to the same treatment when containing 5% by weight or more, whereas the water absorption is 20% by weight or less when the heat treatment corresponding to the drying and crimp sets is performed. Even after the test, the balance of elongation was maintained, and a high water absorption of 20% by weight or more was shown. Moreover, when the fiber of Experiment No. 2 was dried and crimped and crimped, and crimp set was performed at 130 degreeC, the heat resistant stable crimp which was not lost even after boiling was able to be provided. When the cellulose content is 20% by weight or less, spinning and stretching can be performed stably, but when it exceeds 20% by weight, trimming in stretching occurs frequently. In addition, the tensile strength was lowered to 0.9 g / d because the stretching was not possible at 35% by weight.

Example 2

The ratio of the acrylonitrile-based polymer obtained by polymerizing acrylonitrile and methyl acrylate at a ratio of 95% by weight to 5% by weight with a cellulose having a degree of polymerization of 200 was mixed at a ratio of 90/10, which was 60% by weight calcium thiocyanate. It dissolved in aqueous solution and produced the spinning stock solution of 15% of polymer concentration. The resultant was wet-spun with 25 ° C. and 15% by weight aqueous calcium thiocyanate as a coagulant solution, followed by washing with water, 10 times thermal stretching, and drying at 130 ° C. with a heating roller, densifying at 120-150 ° C. The wet heat treatment for 3 minutes was performed, and five types of acrylic fiber samples were obtained. (Samples No. 6 to 10) Absorption rate and the presence of deadlock are shown in Table 2.

No. Acrylonitrile-Based Polymers / Cellulose Wet Heat Treatment Temperature Water absorption agglutination 6 90/10 120 ℃ 20% none 7 90/10 125 ℃ 22% none 8 90/10 130 ℃ 22% none 9 90/10 140 ℃ 28% none 10 90/10 150 ℃ 23% has exist

When the moist heat treatment temperature is 150 ° C. or higher, water becomes a plasticizer and the melting occurs because acrylonitrile starts to melt. Below 140 ° C., fibers without deadlock are obtained.

Example 3

Acrylonitrile, acrylonitrile-based polymer having vinyl acetate at a ratio of 84% to 16% by weight and 85% to 15% by weight, and then immersed in 20% by weight aqueous sodium hydroxide solution for 5 hours, followed by dilute sulfuric acid. The ratio of neutralization, water washing, and dry cellulose having a degree of polymerization of 200 was mixed at a ratio of 90/10 and 80/20, and this was dissolved in 60% by weight aqueous sodium thiocyanate solution to prepare a spinning stock solution having a polymer concentration of 15%. This was subjected to wet spinning with 25 ° C. and 15% by weight aqueous sodium thiocyanate solution as a coagulating solution, followed by washing with water, 10 times hot stretching, drying at 130 ° C. with a heating roller under tension, and densifying at 130 ° C. for 3 minutes. Wet-heat treatment was performed and five kinds of acrylic fiber samples were obtained. (Sample No. 11-14) A water absorption rate and the whiteness of a fiber are shown in Table 3.

No. AN content rate in AN polymer Acrylonitrile-Based Polymers / Cellulose Water absorption Fiber 11 84% 90/10 24% × 12 84% 80/20 26% × 13 85% 90/10 25% ○ 14 85% 80/20 28% ○

When the acrylonitrile content of the acrylonitrile-based polymer is 84% by weight or less, the acrylonitrile-based polymer has low heat resistance, so that coloring occurs by drying, densification and wet heat treatment at 130 ° C., resulting in a decrease in the whiteness of the resulting fiber. . On the other hand, in the acrylonitrile-based polymer of 85% by weight or more, almost no coloration was obtained and good fibers were obtained.

Example 4

Acrylonitrile, vinyl acetate, acrylonitrile-based polymer having a ratio of 84% by weight to 16% by weight and 85% by weight to 15% by weight, and soaked in 20% by weight aqueous sodium hydroxide solution for 5 hours, followed by dilute sulfuric acid. Table 4 shows the results of testing the dissolution in neutralizing, washing with water and drying polymerization degree cellulose in each solvent.

Acrylonitrile-based polymer cellulose  Acetic acid Dissolution Insoluble  Zinc Chloride Solution Dissolution Insoluble  East Ammonia Solution Insoluble Dissolution  NMMO Insoluble Dissolution  Calcium thiocyanate solution Dissolution Dissolution  Sodium thiocyanate solution Dissolution Dissolution

In acetic acid and zinc chloride aqueous solution, acrylonitrile polymer was dissolved but cellulose was not dissolved. In ammonia solution and NMMO, cellulose was dissolved but acrylonitrile polymer was not dissolved. On the other hand, in the calcium thiocyanate and sodium aqueous solution, both of the acrylonitrile polymer and the cellulose could be dissolved.

As described above, in the past, the microvoid originally contained in the swelling gel-toe in the manufacturing process of the acrylic fiber was left in the final product to produce the absorbent acrylic fiber. It was extremely unstable, and in the fiber manufacturing process, especially in the drying and crimp sets, high temperature treatment could not be performed, the heat resistance of the final product, the formability and the crimp stability were insufficient, and the product value of the product was significantly reduced. The present invention provides a macrovoid according to the difference in coagulation properties by wet spinning a mixed polymer solution obtained by dissolving an acrylonitrile-based polymer having essentially different coagulation properties and two kinds of polymers called cellulose into an aqueous thiocyanate solution as a common solvent. It is said that it is industrially important to provide absorbent acrylic fiber which is generated and gives absorbency by the capillary phenomenon based on it, and which has good heat resistance, form retaining property and crimp stability, and which can be processed after the same as conventional acrylic fiber.

Claims (1)

      80 to 95 weight percent acrylonitrile-based polymer containing at least 85 weight percent acrylonitrile units and a polymer consisting of 20 to 5 weight percent cellulose, the water absorption being at least 20 weight percent, and further acrylonitrile An absorbent acrylic fiber characterized by using a thiocyanate aqueous solution as a solvent when dissolving the polymer and the cellulose to form a spinning solution.