JP2017179627A - High full-dull fine-denier acrylic fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high full-dull fine-denier acrylic fiber excellent in fiber-forming property and spinning property even with containing titanium oxide.SOLUTION: The invention is for solving the above described problem, the high full-dull fine-denier acrylic fiber consists of an acrylonitrile-based copolymer containing acrylonitrile of 85 to 94 mass%, a vinyl monomer having copolymerizability with acrylonitrile of 2 to 10 mass% and a vinyl monomer having a sulfonic acid group of 1 to 6 mass% as copolymerization components, contains titanium oxide with average particle diameter of 0.5 to 1.0 μm of 2 to 7 mass% and has single fiber fineness of 0.7 to 2.2 dtex and tensile strength of 2.0 cN/dtex or more.SELECTED DRAWING: None

Description

  The present invention relates to a high full-dal fineness acrylic fiber.

  Since acrylic fibers have a texture similar to wool, they have been used for clothing products such as sweaters and socks, or for pile materials of animal hair-like raised products, taking advantage of the texture and gloss of animal hair. Above all, clothing products used for clothing such as innerwear are required to have a softer texture, and the fineness of the fibers used has been reduced.

  On the other hand, in clothing products used as outer garments for spring and summer, such as cardigans and cut-and-sews, UV shielding is required to prevent sunburn. A means for kneading inorganic particles has been proposed as one means for imparting ultraviolet shielding properties to fibers.

  For example, in patent document 1, ultraviolet shielding property is provided by containing 1-3 mass% of rutile type titanium oxide whose average particle diameter is 80 nm or less.

  Patent Document 2 proposes means for improving spinnability by using a composite fiber having a multilayer structure of two or more layers.

JP 2006-200062 A JP 2005-120512 A

  In the case of imparting ultraviolet shielding properties to the fine fiber, the fabric weight per unit area is lowered, so that it is necessary to increase the content of the ultraviolet shielding particles.

  However, the method of Patent Document 1 has a problem in that thread breakage frequently occurs in the yarn making process due to aggregation of titanium oxide particles. Also, when processing fibers with high concentration of inorganic particles into spun yarn, it causes troubles such as frying and nep in the card process and winding with rollers, resulting in poor processability and decreased yarn quality. There was a problem of loss of opportunity and loss of opportunity due to troubleshooting.

  In addition, the method of Patent Document 2 requires a dedicated facility for performing composite spinning, which requires a technology and cost for introducing the facility.

  Therefore, an object of the present invention is to provide a high-fuller fineness acrylic fiber excellent in yarn-making property and spinnability even if it is a fineness fiber containing titanium oxide at a high concentration.

  The present invention is intended to solve the above-mentioned problems, and the high-fuller fineness acrylic fiber of the present invention comprises 85 to 94% by mass of acrylonitrile and 2 to 10% by mass of a vinyl monomer copolymerizable with acrylonitrile. And acrylonitrile-based copolymer comprising 1 to 6% by weight of a vinyl monomer having a sulfonic acid group as a copolymerization component, and having an average particle size of 0.5 to 1.0 μm. It contains 2 to 7% by mass of titanium oxide, the single fiber fineness is 0.7 to 2.2 dtex, and the tensile strength is 2.0 cN / dtex or more.

  According to the present invention, there is provided a high full-fine fineness acrylic fiber having ultraviolet shielding properties by containing titanium oxide at a high concentration, excellent in fineness and texture, and without impairing the yarn-making property and spinning property. can do.

  The high-fuller fineness acrylic fiber of the present invention is a copolymer of 85 to 94% by mass of acrylonitrile, 2 to 10% by mass of vinyl monomer copolymerizable with acrylonitrile, and 1 to 6% by mass of vinyl monomer having a sulfonic acid group. It is a high fuldal fineness acrylic fiber made of an acrylonitrile-based copolymer contained as a component, and contains 2 to 7% by mass of titanium oxide having an average particle size of 0.5 to 1.0 μm, and a single fiber fineness is 0.7. The tensile strength is 2.0 cN / dtex or more. In the present invention, the phrase that a copolymer contains a monomer as a copolymerization component does not mean that an unpolymerized monomer is included, but has a structure obtained by polymerizing the monomer in the copolymer. Refers to that.

  The acrylonitrile-based copolymer used in the present invention contains 85 to 94% by mass of acrylonitrile as a copolymerization component. When the copolymerization ratio of acrylonitrile is less than 85% by mass, the strength is lowered, the process passability in the spinning process is deteriorated, and the quality of the spun yarn is lowered. Moreover, when the said copolymerization ratio is larger than 94 mass%, ductility will fall remarkably and productivity will be impaired. In addition, in this invention, a copolymerization ratio is a mass ratio of each copolymer component when the mass of the whole acrylonitrile-type copolymer is 100 mass%.

  The acrylonitrile-based copolymer used in the present invention contains 2 to 10% by mass of acrylonitrile and a vinyl monomer copolymerizable as a copolymerization component. The copolymerization ratio of the vinyl monomer copolymerizable with acrylonitrile is preferably 3 to 7% by mass. When the copolymerization ratio of the vinyl monomer copolymerizable with acrylonitrile is less than 2% by mass, the stretchability in the spinning process is poor and stable production becomes difficult. On the other hand, when the copolymerization ratio of the vinyl monomer copolymerizable with the acrylonitrile is more than 10% by mass, the anti-pilling property of the fabric is lowered, and the generation of pills when used as a clothing product increases.

  Examples of vinyl monomers copolymerizable with acrylonitrile include acrylic acid, methacrylic acid or esters thereof, acrylamide, methacrylamide, vinyl acetate, vinyl chloride, vinylidene chloride, and the like. Of these, methyl acrylate, which is an ester of acrylic acid, is preferably used from the viewpoint of excellent stretchability in the spinning process of the acrylonitrile-based copolymer obtained.

  The acrylonitrile-based copolymer used in the present invention contains 1 to 6% by mass of a vinyl monomer having a sulfonic acid group as a copolymerization component. The copolymerization ratio of the vinyl monomer having a sulfonic acid group is preferably 1.2 to 5% by mass. When the copolymerization ratio of the vinyl monomer having a sulfonic acid group is less than 1% by mass, sufficient dyeing performance cannot be obtained, and when it exceeds 6% by mass, the dyeability increases, but it causes dyeing spots. Further, although the denseness of the fibers is increased, the solidification is slow, and the fibers tend to be bonded or broken during the spinning process.

  Examples of the vinyl monomer having a sulfonic acid group include unsaturated sulfonic acids such as allyl sulfonic acid, vinyl sulfonic acid, acrylic sulfonic acid, methallyl sulfonic acid, and p-styrene sulfonic acid, or salts thereof. Among these, sodium methallyl sulfonate is preferably used from the viewpoint of excellent color developability at the time of dyeing a fiber product obtained from the obtained acrylonitrile-based copolymer.

  The polymerization method of the acrylonitrile copolymer used in the present invention may be any polymerization method such as a suspension polymerization method, an emulsion polymerization method, or a solution polymerization method. Examples of the organic solvent used for the polymerization include organic solvents such as dimethyl sulfoxide (hereinafter sometimes referred to as DMSO), dimethylacetamide, dimethylformamide, and the like. Among these, since the acrylonitrile copolymer used in the present invention is excellent in yarn-making property in DMSO wet spinning, the polymerization method and the polymerization solvent are preferably solution polymerization methods using DMSO.

  The polymerization reaction solution of the acrylonitrile-based copolymer used in the present invention can contain a polymerization initiator, a pH adjuster, a molecular weight adjuster, and the like as additives as necessary.

  The high full-dull fineness acrylic fiber of the present invention contains titanium oxide having an average particle size of 0.5 to 1.0 μm. When the average particle size is smaller than 0.5 μm, the titanium oxide is easily aggregated when dispersed in a solution, and causes thread breakage when spinning fine fibers of acrylic fiber. On the other hand, when the thickness exceeds 1.0 μm, thread breakage is induced by the size of the particle diameter even when aggregation does not occur.

  The high fuller fine fineness acrylic fiber of the present invention contains 2 to 7% by mass, preferably 2.5 to 5% by mass of the titanium oxide. When the content of titanium oxide is less than 2% by mass, the ultraviolet shielding performance of the high full-fine fineness acrylic fiber is not sufficient. On the other hand, when the content exceeds 7% by mass, aggregation of titanium oxide occurs in the dispersion and yarn breakage during spinning increases. In addition, in this invention, the content rate of a titanium oxide is a mass ratio of a titanium oxide when the mass of the whole high fludder fineness acrylic fiber is 100 mass%.

  The method of adding titanium oxide to the acrylic fiber is not particularly limited, but a solution in which the organic solvent used for the spinning stock solution or the same acrylonitrile copolymer used for the spinning stock solution is dissolved at a concentration of 5 to 15% by mass. In addition, there may be mentioned a method in which titanium oxide particles are added and dispersed to form a dispersion, and then mixed with the spinning dope in the middle of the spinning dope line.

  The ratio of the acrylonitrile copolymer to the whole spinning dope is preferably 20 to 25% by mass, and in that case, the ratio of the organic solvent is preferably 75 to 80% by mass. The ratio of the acrylonitrile copolymer relative to the entire spinning dope is more preferably 21 to 24% by mass, and the ratio of the organic solvent is more preferably 76 to 79% by mass.

  If the ratio of the acrylonitrile copolymer is 20% by mass or more in the spinning dope, the resulting fibers are less likely to be devitrified and the gloss is not easily lost, and dyeing spots and color developability are easily improved. On the other hand, when the ratio of the acrylonitrile-based copolymer is 25% by mass or less, the spinning property is easily improved.

  The spinning dope thus prepared can be spun using a normal spinning device.

  Examples of the organic solvent used as a coagulation bath in the case of wet spinning include DMSO, dimethylformamide, dimethylacetamide and the like. Among them, a DMSO aqueous solution that has a high solvent diffusion coefficient and excellent spinning properties when wet-spun acrylonitrile-based polymer is preferably used.

  The high full dull fineness acrylic fiber of the present invention has a single fiber fineness of 0.7 to 2.2 dtex. The single fiber fineness is preferably 1.1 to 1.7 dtex. When the single fiber fineness is less than 0.7 dtex, an increase in sinking cotton into the cylinder and a poor transfer to the doffer occur during the carding process, and the spinnability is significantly reduced. Moreover, when it exceeds 2.2 dtex, a texture will become hard when it is set as clothing products, and it is not suitable for clothing products.

  The high full-dull fineness acrylic fiber of the present invention has a tensile strength of 2.0 cN / dtex or more. As a result, even if it is a fine-fine acrylic fiber to which titanium oxide particles are added at a high concentration, it is possible to maintain good process passability during spinning, and if the tensile strength is lower than 2.0 cN / dtex, spinning is possible. When processing into yarn, troubles such as frying and nep in the carding process and roller wrapping are caused, and the productivity is significantly reduced. The tensile strength, for example, by increasing the copolymerization ratio of acrylonitrile, reducing the content of titanium oxide, increasing the draw ratio, making the drying densification conditions higher temperature, longer time, etc. Can be high.

  The cross-sectional shape of the high-full-dull fineness acrylic fiber of the present invention is not particularly limited, and may be any cross-sectional shape such as a round shape, a β shape, a C shape, a triangular shape, a flat shape, a dock bone shape, and a multileaf shape. There may be.

  The high fuller fine fineness acrylic fiber of the present invention is composed of a single acrylonitrile copolymer used in the present invention, an acrylonitrile copolymer used in the present invention, and another acrylonitrile copolymer used in the present invention. The polymer is mixed inhomogeneously, and the acrylonitrile copolymer used in the present invention and the other acrylonitrile copolymer used in the present invention are a composite structure such as a core-sheath structure, a side-by-side structure, or a multilayer structure. It may have. In addition, the high full-dull fineness acrylic fiber of the present invention may be uniform or thick in the length direction.

  The high full-dal fineness acrylic fiber of the present invention can be produced, for example, by the following method. As a spinning method for obtaining the high fuller fine fineness acrylic fiber of the present invention, an acrylonitrile-based copolymer containing titanium oxide is discharged from a spinneret hole into air or an inert atmosphere, and then the solvent is evaporated by heat to solidify. Dry spinning, wet spinning in which the polymer discharged from the spinneret hole is directly discharged into the coagulation bath, and the polymer discharged from the spinneret hole is once discharged into air or an inert atmosphere and then into the coagulation bath. Various spinning methods such as dry and wet spinning to be introduced can be employed. After spinning by various spinning methods, high-fuller fineness acrylic fibers can be obtained by heat drawing, washing with water, drying and densifying, applying an oil agent, and performing crimping and heat relaxation treatment.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

(1) Average particle diameter of titanium oxide Regarding the average particle diameter of titanium oxide, 10 mg of titanium oxide to be added is dispersed in 150 mL of DMSO, and the laser diffraction / scattering particle size distribution measuring apparatus LA-920 manufactured by HORIBA is used. It measured by the wet method and the flow system.

(2) Single fiber fineness and tensile strength Measured according to JIS L1015: 2010 chemical fiber staple test method.

(3) Evaluation of yarn-making property Regarding the yarn-making property, “A” indicates that there is no yarn breakage on the die surface and no wrap around the drawing roller, and the yarn-making property was accepted. Further, “B” indicates that the yarn breakage on the base and some single fiber winding around the roller are “B”, and “C” indicates that the yarn is frequently wound.

(4) Evaluation of spinnability With respect to spinnability, the case where there was no cylinder winding around the card and titanium oxide was not dropped off in each step was designated as “A”, and the spinnability passed. Also, the spinning performance was rejected as “B” for the case where the cylinder was wound around the card and the titanium oxide was slightly dropped, and “C” for the case where the titanium oxide was frequently removed.

(5) Evaluation of UV shielding ratio The high-full dull fineness acrylic fibers obtained in the examples and comparative examples were each cut to 38 mm, and spun yarns of Ac100 and 2/53 were obtained by short spinning. The spun yarn was knitted with a smooth knitting and 18 gauge. The obtained knitted fabric was dyed with a 1.0% owf Clicklic White TK dye solution manufactured by Shigensei Chemical Co., Ltd. under a bath ratio of 1:15, a temperature of 97 ° C., and a time of 30 minutes to prepare a knitted fabric. The knitted fabric was irradiated with ultraviolet rays having a wavelength of 280 nm to 400 nm by a spectrophotometer, and the average transmittance was measured. The value obtained by subtracting the average transmittance from 100 was defined as the ultraviolet shielding rate.
UV shielding factor (%) = 100− [average transmittance (%) at a wavelength of 280 to 400 nm]
In the evaluation, an ultraviolet shielding ratio of 95% or more was AA, 90% or more and less than 95% was “A”, less than 90% was “C”, “AA, A” was passed, and “C” was rejected.

(6) Evaluation of the texture of the knitted fabric The evaluation method of the texture of the knitted fabric is such that five judges judge the feeling of the knitted fabric for the texture evaluation and are judged to have sufficient softness. “C” was assigned to “A”, which was judged to be lacking in softness or to have a sharp feeling. When all 5 people wear A, the judgment result is AA, when A is 3 or more, the judgment result is A, “AA, A” is a passing texture, and when C is 3 or more The determination result was C, and “C” was evaluated as a failure of the texture.

[Example 1]
By solution polymerization using DMSO as a solvent, an acrylonitrile copolymer concentration containing 91.3% by mass of acrylonitrile, 5.0% by mass of methyl acrylate, and 1.2% by mass of sodium methallylsulfonate as a copolymerization component is 22 A 4% by mass acrylonitrile copolymer solution was obtained. To this acrylonitrile-based copolymer solution, titanium oxide having an average particle size of 0.6 μm was added so that the content of titanium oxide was 2.5% by mass with respect to the mass of high-fuller fineness acrylic fiber. Mixing was performed to prepare a spinning dope. The spinning solution was used for wet spinning into a 60% by mass DMSO aqueous solution from a round hole cap having a hole diameter of 0.050 mm. Further, the film was stretched 6 times in hot water at 95 ° C., washed with water, dried and densified with hot air at 160 ° C. for 1 minute, imparted with crimp, and a single fiber fineness of 1.7 dtex and a tensile strength of 2.8 cN. An / dtex high-fludal fine fineness acrylic fiber was obtained.

[Example 2]
By solution polymerization using DMSO as a solvent, an acrylonitrile-based copolymer concentration containing 88.9% by mass of acrylonitrile, 4.9% by mass of methyl acrylate, and 1.2% by mass of sodium methallylsulfonate as a copolymerization component is 22 A 4% by mass acrylonitrile copolymer solution was obtained. To this acrylonitrile-based copolymer solution, titanium oxide having an average particle size of 0.6 μm was added so that the content of titanium oxide was 5.0% by mass with respect to the mass of the high fuller fineness acrylic fiber. Mixing was performed to prepare a spinning dope. The spinning solution was used for wet spinning into a 60% by mass DMSO aqueous solution from a round hole cap having a hole diameter of 0.050 mm. Further, the film was stretched 6 times in hot water at 95 ° C., washed with water, dried and densified with hot air at 160 ° C. for 1 minute, imparted with crimp, and a single fiber fineness of 1.7 dtex and a tensile strength of 2.6 cN. An / dtex high-fludal fine fineness acrylic fiber was obtained.

[Example 3]
By solution polymerization using DMSO as a solvent, an acrylonitrile copolymer concentration containing 85.0% by mass of acrylonitrile, 3.5% by mass of methyl acrylate, and 4.5% by mass of sodium methallyl sulfonate as a copolymerization component is 22 A 4% by mass acrylonitrile copolymer solution was obtained. To this acrylonitrile-based copolymer solution, titanium oxide having an average particle size of 1.0 μm was added so that the content of titanium oxide was 7.0% by mass with respect to the mass of high-full-dal fineness acrylic fiber. Mixing was performed to prepare a spinning dope. The spinning solution was used for wet spinning into a 60% by mass DMSO aqueous solution from a round hole cap having a pore diameter of 0.055 mm. Further, it is stretched 6 times in hot water at 95 ° C., washed with water, dried and densified with hot air at 160 ° C. for 1 minute, imparted with crimps, single fiber fineness of 2.2 dtex, and tensile strength of 2.2 cN. An / dtex high-fludal fine fineness acrylic fiber was obtained.

[Example 4]
By solution polymerization using DMSO as a solvent, an acrylonitrile-based copolymer concentration containing 88.9% by mass of acrylonitrile, 4.9% by mass of methyl acrylate, and 1.2% by mass of sodium methallylsulfonate as a copolymerization component is 22 A 4% by mass acrylonitrile copolymer solution was obtained. To this acrylonitrile-based copolymer solution, titanium oxide having an average particle size of 0.6 μm was added so that the content of titanium oxide was 5.0% by mass with respect to the mass of the high fuller fineness acrylic fiber. Mixing was performed to prepare a spinning dope. The spinning solution was used for wet spinning into a 60% by mass DMSO aqueous solution from a round hole cap having a hole diameter of 0.050 mm. Further, the film was stretched 6 times in hot water at 95 ° C., washed with water, dried and densified with hot air at 160 ° C. for 1 minute, imparted with crimp, and a single fiber fineness of 1.0 dtex and a tensile strength of 2.4 cN. An / dtex high-fludal fine fineness acrylic fiber was obtained.

[Example 5]
By solution polymerization using DMSO as a solvent, an acrylonitrile-based copolymer concentration containing 88.9% by mass of acrylonitrile, 4.9% by mass of methyl acrylate, and 1.2% by mass of sodium methallylsulfonate as a copolymerization component is 22 A 4% by mass acrylonitrile copolymer solution was obtained. To this acrylonitrile-based copolymer solution, titanium oxide having an average particle size of 1.0 μm was added so that the content of titanium oxide was 5.0% by mass with respect to the mass of high-full-dull fineness acrylic fiber. Mixing was performed to prepare a spinning dope. The spinning solution was used for wet spinning into a 60% by mass DMSO aqueous solution from a round hole cap having a hole diameter of 0.050 mm. Further, the film is stretched 6 times in hot water at 95 ° C., washed with water, dried and densified with hot air at 160 ° C. for 1 minute, imparted with crimps, a single fiber fineness of 1.0 dtex, and a tensile strength of 2.3 cN. An / dtex high-fludal fine fineness acrylic fiber was obtained.

[Example 6]
By solution polymerization using DMSO as a solvent, an acrylonitrile-based copolymer concentration containing 88.9% by mass of acrylonitrile, 4.9% by mass of methyl acrylate, and 1.2% by mass of sodium methallylsulfonate as a copolymerization component is 22 A 4% by mass acrylonitrile copolymer solution was obtained. To this acrylonitrile-based copolymer solution, titanium oxide having an average particle size of 0.6 μm was added so that the content of titanium oxide was 5.0% by mass with respect to the mass of the high fuller fineness acrylic fiber. Mixing was performed to prepare a spinning dope. The spinning solution was used for wet spinning into a 60% by mass DMSO aqueous solution from a round hole cap having a hole diameter of 0.050 mm. Further, the film was stretched 6 times in hot water at 95 ° C., washed with water, dried and densified with hot air at 160 ° C. for 1 minute, imparted with crimps, single fiber fineness 0.7 dtex, and tensile strength 2.6 cN. An / dtex high-fludal fine fineness acrylic fiber was obtained.

[Comparative Example 1]
By solution polymerization using DMSO as a solvent, the concentration of acrylonitrile-based copolymer containing 92.7% by mass of acrylonitrile, 6.0% by mass of methyl acrylate, and 1.2% by mass of sodium methallylsulfonate as a copolymerization component is 22 A 4% by mass acrylonitrile copolymer solution was obtained. To this acrylonitrile-based copolymer solution, titanium oxide having an average particle size of 0.6 μm is added and mixed so that the content of titanium oxide is 0.1% by mass with respect to the mass of acrylic fiber, and spinning is performed. Stock solutions were prepared. The spinning solution was used for wet spinning into a 60% by mass DMSO aqueous solution from a round hole cap having a hole diameter of 0.050 mm. Further, the film was stretched 6 times in hot water at 95 ° C., washed with water, dried and densified with hot air at 160 ° C. for 1 minute, imparted with crimp, and a single fiber fineness of 1.7 dtex, tensile strength of 3.0 cN An acrylic fiber of / dtex was obtained.

[Comparative Example 2]
By solution polymerization using DMSO as a solvent, an acrylonitrile-based copolymer concentration containing 84.0% by mass of acrylonitrile, 4.8% by mass of methyl acrylate, and 4.2% by mass of sodium methallylsulfonate as a copolymerization component is 22 A 4% by mass acrylonitrile copolymer solution was obtained. To this acrylonitrile-based copolymer solution, titanium oxide having an average particle size of 0.6 μm is added and mixed so that the content of titanium oxide is 7.0% by mass with respect to the mass of acrylic fiber, and spinning is performed. Stock solutions were prepared. The spinning solution was used for wet spinning into a 60% by mass DMSO aqueous solution from a round hole cap having a hole diameter of 0.050 mm. Furthermore, it is stretched 5 times in hot water at 95 ° C., washed with water, dried and densified with hot air at 150 ° C. for 1 minute, imparted crimps, and has a single fiber fineness of 1.7 dtex and a tensile strength of 1.7 cN. An acrylic fiber of / dtex was obtained.

[Comparative Example 3]
By solution polymerization using DMSO as a solvent, an acrylonitrile-based copolymer concentration containing 85.3% by mass of acrylonitrile, 3.6% by mass of methyl acrylate, and 1.1% by mass of sodium methallylsulfonate as a copolymerization component is 22 A 4% by mass acrylonitrile copolymer solution was obtained. To this acrylonitrile copolymer solution, titanium oxide having an average particle diameter of 1.0 μm was added and mixed so that the content of titanium oxide was 10.0% by mass with respect to the fiber weight, and the spinning dope was Prepared. The spinning solution was used for wet spinning into a 60% by mass DMSO aqueous solution from a round hole cap having a hole diameter of 0.050 mm. Further, the film is stretched 5 times in hot water at 95 ° C., washed with water, dried and densified with hot air at 150 ° C. for 1 minute, imparted with crimps to give a single fiber fineness of 2.2 dtex and a tensile strength of 1.8 cN. An acrylic fiber of / dtex was obtained.

[Comparative Example 4]
By solution polymerization using DMSO as a solvent, an acrylonitrile-based copolymer concentration containing 88.9% by mass of acrylonitrile, 4.9% by mass of methyl acrylate, and 1.2% by mass of sodium methallylsulfonate as a copolymerization component is 22 A 4% by mass acrylonitrile copolymer solution was obtained. To this acrylonitrile-based copolymer solution, titanium oxide having an average particle size of 0.05 μm was added and mixed so that the content of titanium oxide was 5.0% by mass with respect to the mass of acrylic fiber, and spinning was performed. Stock solutions were prepared. The spinning solution was used for wet spinning into a 60% by mass DMSO aqueous solution from a round hole cap having a hole diameter of 0.050 mm. Further, it is stretched 6 times in hot water at 95 ° C., washed with water, dried and densified with hot air at 160 ° C. for 1 minute, imparted crimps, and has a single fiber fineness of 1.7 dtex and a tensile strength of 2.1 cN. An acrylic fiber of / dtex was obtained.

[Comparative Example 5]
By solution polymerization using DMSO as a solvent, an acrylonitrile-based copolymer concentration containing 88.9% by mass of acrylonitrile, 4.9% by mass of methyl acrylate, and 1.2% by mass of sodium methallylsulfonate as a copolymerization component is 22 A 4% by mass acrylonitrile copolymer solution was obtained. To this acrylonitrile-based copolymer solution, titanium oxide having an average particle size of 1.5 μm was added and mixed so that the content of titanium oxide was 5.0% by mass with respect to the mass of acrylic fiber, and spinning was performed. Stock solutions were prepared. The spinning solution was used for wet spinning into a 60% by mass DMSO aqueous solution from a round hole cap having a hole diameter of 0.050 mm. Further, the film is stretched 6 times in hot water at 95 ° C., washed with water, dried and densified with hot air at 160 ° C. for 1 minute, imparted with crimps, a single fiber fineness of 1.0 dtex, and a tensile strength of 2.3 cN. An acrylic fiber of / dtex was obtained.

[Comparative Example 6]
By solution polymerization using DMSO as a solvent, an acrylonitrile-based copolymer concentration containing 88.9% by mass of acrylonitrile, 4.9% by mass of methyl acrylate, and 1.2% by mass of sodium methallylsulfonate as a copolymerization component is 22 A 4% by mass acrylonitrile copolymer solution was obtained. To this acrylonitrile-based copolymer solution, titanium oxide having an average particle size of 1.0 μm is added and mixed so that the content of titanium oxide is 5.0% by mass with respect to the mass of acrylic fiber, and spinning is performed. Stock solutions were prepared. The spinning solution was used for wet spinning into a 60% by mass DMSO aqueous solution from a round hole cap having a hole diameter of 0.050 mm. Further, the film was stretched 6 times in hot water at 95 ° C., washed with water, dried and densified with hot air at 160 ° C. for 1 minute, imparted with crimps, single fiber fineness of 3.3 dtex, and tensile strength of 2.7 cN. An acrylic fiber of / dtex was obtained.

[Comparative Example 7]
By solution polymerization using DMSO as a solvent, an acrylonitrile-based copolymer concentration containing 88.9% by mass of acrylonitrile, 4.9% by mass of methyl acrylate, and 1.2% by mass of sodium methallylsulfonate as a copolymerization component is 22 A 4% by mass acrylonitrile copolymer solution was obtained. To this acrylonitrile-based copolymer solution, titanium oxide having an average particle diameter of 0.6 μm is added and mixed so that the content of titanium oxide is 5.0% by mass with respect to the mass of acrylic fiber, and spinning is performed. Stock solutions were prepared. Using the above spinning solution, wet spinning was carried out into a 60% by mass DMSO aqueous solution from a round hole cap having a pore diameter of 0.050 mm. Further, the film was stretched 6 times in hot water at 95 ° C., washed with water, dried and densified with hot air at 160 ° C. for 1 minute, imparted with crimp, and a single fiber fineness of 0.1 dtex and a tensile strength of 2.6 cN. An acrylic fiber of / dtex was obtained.

[Comparative Example 8]
By solution polymerization using DMSO as a solvent, an acrylonitrile copolymer concentration containing 87.1% by mass of acrylonitrile, 1.6% by mass of methyl acrylate, and 8.3% by mass of sodium methallyl sulfonate as a copolymerization component is 22 A 4% by mass acrylonitrile copolymer solution was obtained. To this acrylonitrile-based copolymer solution, titanium oxide having an average particle size of 0.6 μm was added and mixed so that the content of titanium oxide was 3.0% by mass with respect to the mass of acrylic fiber, and spinning was performed. Stock solutions were prepared. The spinning solution was used for wet spinning into a 60% by mass DMSO aqueous solution from a round hole cap having a hole diameter of 0.050 mm. Further, the film was stretched 6 times in hot water at 95 ° C., washed with water, dried and densified with hot air at 160 ° C. for 1 minute, imparted with crimp, and a single fiber fineness of 1.0 dtex and a tensile strength of 2.6 cN. An acrylic fiber of / dtex was obtained.

  About the high full-dull fineness acrylic fiber produced in Examples 1-8 and Comparative Examples 1-8, the above-mentioned (3) Evaluation of yarn-making property, (4) Evaluation of spinnability, (5) Ultraviolet shielding rate Evaluation, (6) Evaluation of knitted fabric texture was performed, and the results are shown in Tables 1 and 2. As a result, it was clear that the high-full-dull fineness acrylic fiber in the present invention was excellent in knitted fabric texture and ultraviolet shielding properties, and also excellent in yarn production and spinnability.

Claims (1)

  High fuldal comprising acrylonitrile-based copolymer containing acrylonitrile 85 to 94 mass%, vinyl monomer 2 to 10 mass% copolymerizable with acrylonitrile, and vinyl monomer 1 to 6 mass% having sulfonic acid group as copolymerization components It is a fine fiber acrylic fiber, contains 2 to 7% by mass of titanium oxide having an average particle size of 0.5 to 1.0 μm, single fiber fineness is 0.7 to 2.2 dtex, and tensile strength is 2. High full dull fineness acrylic fiber that is 0 cN / dtex or more.