JP6065976B2 - Acrylic fiber and its manufacturing method, spun yarn and knitted fabric using the fiber - Google Patents

Description

  The present invention relates to an acrylic fiber having excellent crimp characteristics and anti-pill properties, a method for producing the fiber, and a spun yarn and a knitted fabric using the fiber.

Acrylic fiber has bulkiness and heat retention similar to wool, making use of excellent characteristics such as coloring properties, sharpness, fastness, light resistance, corrosion resistance, clothing field, interior field, Widely used in the material field.
On the other hand, wool is excellent in bulkiness, compression resistance, and elasticity, but acrylic fiber is said to be similar to wool, but compression resistance and elasticity do not reach wool. For this reason, conventionally, studies have been made to impart the above-mentioned properties to acrylic fibers and bring them closer to wool.

  For example, in Japanese Patent Application Laid-Open No. 63-190019 (Patent Document 1) and Japanese Patent Application Laid-Open No. 1-104825 (Patent Document 2), two or more types of copolymers having different copolymer compositions are composite-spun and two layers are formed. Alternatively, a technique having a multilayer structure is disclosed. These composite fibers are fibers produced by combining the spinning dope in a layer using a multi-layer device, and it is difficult to stably obtain a side-by-side shape and it is difficult to obtain sufficient bulkiness.

  Further, for example, Japanese Patent Application Laid-Open No. 7-197323 (Patent Document 3) discloses a technique in which two types of acrylonitrile-based polymers having a difference in hydrophilicity are subjected to composite spinning in an eccentric or parallel manner. Although this composite fiber reversibly changes its crimped form when wet and dry, it has a self-crimping property, but it has a texture such as bulkiness and resilience similar to the wool intended for the present invention. Not in.

  Furthermore, for example, according to Japanese Patent Application Laid-Open No. 59-192717 (Patent Document 4), a technique for composite spinning of two types of polymers having different shrinkage properties into a side-by-side type is also disclosed. The composite fiber by this method can obtain a bulky fabric due to the bulkiness, but the shrinkage in the fiber axis direction is also expressed by hot water treatment such as dyeing, so that the texture after shrinkage becomes hard There's a problem.

  Since these composite fibers according to the prior art have a high contraction rate in the fiber axis direction, it is generally necessary to perform dyeing in a wrinkle state (wrinkle dyeing) in yarn dyeing. In addition, when trying to dye with fabric, it is necessary to control the shrinkage in the dyeing process after preparing the coarse fabric in advance after calculating the size of the fabric after shrinkage, so advanced processing technology Was necessary.

JP 63-190019 A JP-A-1-104825 JP-A-7-197323 JP 59-192717 A

  An object of the present invention is to solve the above-mentioned problems in the prior art, and basically to provide an acrylic fiber having excellent crimp characteristics and excellent crimp resistance.

The acrylic fiber of the present invention has a single fiber fineness of 1.7 to 6.6 dtex, a crimp rate measured according to JIS L1015 (2010) of 15% or more, and bulkiness measured by the following method. 380 cm ³ / g or more der is, acrylonitrile copolymer containing ～97.8 wt% 93.5 wt% of acrylonitrile copolymer a and acrylonitrile units containing acrylonitrile units 90 wt% to 95 wt% B These are acrylic fibers that are combined in a side-by-side manner at a ratio of 1: 3 to 3: 1 in the area ratio in the fiber cross section in the fiber axis direction .
(Bulkness measuring method)
(1) Collect about 10 g of acrylic fiber cut to 51 mm and open it to such an extent that the fibers do not adhere to each other.
(2) Fractionate 1.5 g of the opened acrylic fiber.
(3) Divide into approximately 0.15 g portions, gently drop into a 1000 mL graduated cylinder with a bottom area of 33.17 cm ² and fill evenly so that there is no gap.
(4) A 6 g load disk is lowered into the measuring cylinder, and after 2 minutes, the volume vcm ³ occupied by the acrylic fiber is measured.
(5) Bulkiness is calculated by the following equation .
Bulkiness (cm ³ /g)=v÷1.5
In addition, measurement is performed on three specimens, and the average value thereof is taken as the result.

The acrylic fiber of the present invention preferably has a product of nodule strength (cN / dtex) and nodule elongation (%) of 10 to 25.
The acrylic fiber of the present invention preferably has a number of crimps of 20 / 2.54 cm to 50 / 2.54 cm.

  The acrylic fiber of the present invention comprises an acrylonitrile copolymer A containing 90% to 95% by weight of acrylonitrile units and an acrylonitrile copolymer B containing 93.5% to 97.8% by weight of acrylonitrile units. It is preferable that the cross section of the fiber perpendicular to the axis is combined with the side-by-side type at a ratio of 1: 3 to 3: 1 in area ratio.

  In the acrylic fiber of the present invention, the difference between the content (% by mass) of the acrylonitrile unit in the copolymer A and the content (% by mass) of the acrylonitrile unit from the copolymer B is 2 or more. It is preferable.

  The acrylic fiber of the present invention is a copolymer obtained by copolymerizing the copolymer A with 90% by mass to 95% by mass of acrylonitrile units and 5% by mass to 10% by mass of unsaturated monomers copolymerizable with acrylonitrile units. The copolymer B is 93.5% by mass to 97.8% by mass of acrylonitrile units, 2% by mass to 5% by mass of unsaturated monomer units copolymerizable with acrylonitrile units, and sulfonic acid groups. A copolymer obtained by copolymerizing 0.2% by mass to 1.5% by mass of the containing monomer unit is preferable.

In the acrylic fiber of the present invention, the monomer unit contained as an unsaturated monomer unit copolymerizable with the acrylonitrile unit in the copolymer A and the copolymer B is a vinyl acetate unit, and sulfonic acid The group-containing monomer unit is preferably a sodium methallyl sulfonate unit.
The acrylic fiber of the present invention is preferably contracted by 2% to 7%.

  The acrylic fiber production method of the present invention comprises a spinning stock solution A ′ in which a copolymer A containing 90% by mass to 95% by mass of acrylonitrile units is dissolved in a solvent, and 93.5% by mass to 97.8% by mass of acrylonitrile units. A method for producing acrylic fibers comprising a spinning solution B ′ in which a copolymer B dissolved in a solvent is discharged into a spinning bath having a solvent concentration of 35% to 60% from a nozzle in a side-by-side shape to form a composite fiber. The difference between the content (mass%) of the acrylonitrile unit content of the coalescence A and the content (mass%) of the acrylonitrile unit content of the copolymer B is 2 or more.

  In the method for producing acrylic fibers of the present invention, the copolymer A is 90% to 95% by mass of acrylonitrile units, and 5% to 10% by mass of unsaturated monomers copolymerizable with acrylonitrile units. The copolymer B is 93.5% by mass to 97.8% by mass of acrylonitrile units, 2% by mass to 5% by mass of unsaturated monomer units copolymerizable with the acrylonitrile units, and A copolymer in which 0.2% by mass to 1.5% by mass of a sulfonic acid group-containing monomer unit is copolymerized is preferable.

  In the method for producing an acrylic fiber of the present invention, the unsaturated monomer unit copolymerizable with the acrylonitrile unit in the copolymer A and the copolymer B is a vinyl acetate unit, and the sulfonic acid group-containing monomer unit is It is preferably a sodium methallyl sulfonate unit.

  The method for producing an acrylic fiber of the present invention comprises a step of discharging a spinning stock solution A ′ and a spinning stock solution B ′ in a side-by-side shape from a nozzle to a spinning bath to form a composite fiber, and 3.0 times to 5.0 times. It is preferable to include a step of primary stretching at a stretching ratio, a step of relaxing heat treatment in saturated steam of 90 kPa to 230 kPa, and a step of performing a secondary stretching process at a stretching ratio of 1.05 to 1.20 times. .

The spun yarn of the present invention contains 30% by mass or more of the acrylic fiber.
The spun yarn of the present invention is preferably a spun yarn containing 3% by mass to 15% by mass of conductive acrylic fiber.

The knitted fabric of the present invention contains 50% by mass or more of the spun yarn and has an anti-pill property of 4th or higher.
The knitted fabric of the present invention preferably has a dimensional change rate after repeated washing of 10 times within ± 3% in each of the vertical and horizontal directions.

  The acrylic fiber of the present invention is an acrylic fiber that is excellent in anti-pill property, bulkiness, compression resistance and elasticity, and has a texture similar to wool. Clothing products using this acrylic fiber have the same bulkiness and texture as products using wool, and can compensate for the disadvantages inherent in wool such as anti-pill properties and easy care properties.

  Hereinafter, the present invention will be described in detail.

The acrylic fiber of the present invention has a crimp rate of 15% or more and a bulkiness of 380 cm ³ / g or more.
If the crimp rate is 15% or more, good bulkiness and resilience can be imparted to the product. From the above viewpoint, the crimp rate is more preferably 17% or more, and further preferably 20% or more. The upper limit is preferably 30% or less from the viewpoint that the texture of the product does not become hard.
If the bulkiness is 380 cm ³ / g or more, a good bulkiness and rebound can be imparted to the product. From the above viewpoint, the bulkiness is more preferably 440 cm ³ / g or more. The upper limit is preferably 600 cm ³ / g or less from the point that the texture of the product does not become hard.

The acrylic fiber of the present invention preferably has a single fiber fineness of 1.7 to 6.6 dtex, and a product of nodule strength (cN / dtex) and nodule elongation (%) of 10 to 25.
If the single fiber fineness is 1.7 dtex or more, the product can be provided with good bulkiness and resilience similar to wool. Moreover, when the single fiber fineness is 6.6 dtex or less, it is possible to prevent the product from becoming hard and having a rough texture. From the above viewpoint, the single fiber fineness is more preferably 2.2 dtex to 5.6 dtex.
In the acrylic fiber of the present invention, the knot strength (cN / dtex) × the knot elongation (%) is preferably in the range of 10 to 25, and more preferably 15 to 25. Hereinafter, in this specification, the nodule strength (cN / dtex) may be referred to as “DKS” and the nodule elongation (%) may be referred to as “DKE”.
If DKS × DKE is 10 or more, problems such as the occurrence of fly in post-processing steps such as spinning and a decrease in yarn strength are unlikely to occur. Moreover, if DKS × DKE is 25 or less, excellent anti-pill properties can be maintained.
The value of DKS × DKE is a value used by those skilled in the art as an index of anti-pill property.

The acrylic fiber of the present invention preferably has a number of crimps of 20 / 2.54 cm to 50 / 2.54 cm, and more preferably 25 / 2.54 cm to 45 / 2.54 cm.
If the crimp rate is 20 pieces / 2.54 cm or more, it is preferable in terms of imparting a feeling of elasticity, compression repulsion, and bulkiness, and if it is 50 pieces / 2.54 cm or less, the texture of the product becomes too hard. Can be prevented.

The acrylic fiber of the present invention comprises an acrylonitrile copolymer A containing 90% by mass to 95% by mass of acrylonitrile units and an acrylonitrile copolymer B containing 93.5% by mass to 97.8% by mass of acrylonitrile units. It is preferable to be compounded in a side-by-side manner at a ratio of 1: 3 to 3: 1 in the area ratio in the fiber cross section in the fiber axis direction.
When the copolymer A and the copolymer B are combined in a side-by-side manner, fine crimps are developed, and elasticity, crimp rate, and bulkiness tend to be high.
If the area ratio is from 1: 3 to 3: 1, a good bulkiness and resilience can be imparted to the product without lowering the spinning stability. From the above viewpoint, the area ratio is more preferably a ratio of 2: 3 to 3: 2.

When the acrylic fiber of the present invention is spun, the copolymer A and the copolymer B are combined in a side-by-side manner at a ratio of 1: 3 to 3: 1 in the area ratio in the fiber cross section in the fiber axis direction. It is preferable that 80 mass% or more is contained in the fiber bundle discharged from one nozzle.
By including 80% by mass or more of the side-by-side type composite fiber, a good bulkiness and repulsion can be imparted to the product. From the above viewpoint, the content of the side-by-side type composite fiber is more preferably 90% by mass or more.

When the content of the acrylonitrile unit in the copolymer A is 90% by mass to 95% by mass, sufficient shrinkage can be exhibited while maintaining the fiber properties necessary for the fiber for clothing, particularly the form stability. It is possible and preferable.
When the content of the acrylonitrile unit in the copolymer B is 93.5% by mass to 97.8% by mass, a difference in shrinkage from the copolymer A is easily exhibited, and it is possible to impart bulkiness and resilience. It is preferable.

In the acrylic fiber of the present invention, the difference between the content (mass%) of the acrylonitrile unit in the copolymer A and the content (mass%) of the acrylonitrile unit in the polymer B is 2 or more. Preferably there is.
If the difference is 2 or more, fine crimp is likely to occur, and the crimp rate and bulkiness are likely to be high.
From the above viewpoint, the difference is more preferably 3 or more.

  In the acrylic fiber of the present invention, the copolymer A is a copolymer obtained by copolymerizing 90% by mass to 95% by mass of acrylonitrile units and 5% by mass to 10% by mass of unsaturated monomer units copolymerizable with acrylonitrile units. A copolymer, wherein the copolymer B contains 93.5% by mass to 97.8% by mass of acrylonitrile units, 2% by mass to 5% by mass of unsaturated monomer units copolymerizable with acrylonitrile units, and sulfonic acid groups A copolymer obtained by copolymerizing 0.2% by mass to 1.5% by mass of the containing monomer unit is preferable.

  By copolymerizing one copolymer B with a sulfonic acid group-containing monomer unit in an amount of 0.2% by mass to 1.5% by mass, the difference in dyeability between the copolymer A and the copolymer B increases. However, it is preferable from the viewpoint of preventing the occurrence of flicker due to light and shade color differences.

As the unsaturated monomer unit copolymerizable with the acrylonitrile unit, for example, acrylic acid, methacrylic acid and derivatives thereof, vinyl acetate, acrylamide, methacrylamide, vinyl chloride, vinylidene chloride and the like can be used.
Among these, vinyl acetate is more preferable in terms of availability and cost.

Examples of the sulfonic acid group-containing monomer unit include sodium vinylbenzene sulfonate, sodium methallyl sulfonate, sodium acrylamide methyl sulfonate, sodium parasulfophenyl methallyl ether, and the like.
Of these, sodium methallyl sulfonate is preferable in terms of availability and cost.

  The content of the unsaturated monomer copolymerizable with the acrylonitrile unit in the copolymer A may be in the range of 5% by mass to 10% by mass. When the content is 5% by mass or more, sufficient shrinkage can be maintained, and when it is 10% by mass or less, the fiber physical properties necessary for the fiber for clothing, particularly the form stability, are maintained. Can do.

  The content of the unsaturated monomer copolymerizable with the acrylonitrile unit in the copolymer B may be in the range of 2% by mass to 5% by mass. By being in this range, good bulkiness and resilience can be imparted due to a difference in shrinkage from the copolymer A. The sulfonic acid group-containing monomer unit may be in the range of 0.2% by mass to 1.5% by mass. When the content of the sulfonic acid group-containing monomer unit is within this range, the difference in dyeing property between the polymer A and the polymer B does not become too large, and the occurrence of flicker due to the color difference can be prevented.

The acrylic fiber of the present invention is preferably contracted in the range of 2% to 7%. If the shrinkage rate is 2% or more, latent fine crimps appear and a feeling of swelling is obtained, and if the shrinkage rate is 8% or less, hardening of the texture after shrinkage can be prevented. The shrinkage rate is more preferably 4% to 7% from the viewpoint.
In addition, since the shrinkage rate is relatively low, there are few restrictions in the dyeing process, and cheese dyeing and wrinkle dyeing, which are general yarn dyeing processes, as well as anti-dying on fabric can be easily performed.

  The polymerization degree of the copolymer A and the copolymer B is such that the specific viscosity (0.5 g of the polymer is dissolved in 100 mL of dimethylformamide and measured at 30 ° C.) is in the range of 0.12 to 0.21. Preferably there is. In addition, the molecular weight is not particularly limited as long as it is a range that can be used for production of a normal acrylic fiber, but it is usually preferably in the range of 100,000 to 1,000,000.

The acrylic fiber of the present invention can be produced, for example, by the following method.
Copolymer A and Copolymer B are each dissolved in a solvent used for normal acrylic fiber spinning, such as dimethylacetamide, dimethylformamide, dimethylsulfoxide, and the like, and used as a spinning dope having a solid content of 20% by mass to 28% by mass. . The spinning stock solution preferably has a viscosity (JIS Z8803 falling ball viscosity method: measuring temperature 50 ° C.) of 50 to 500 poise. If the solid content is 20% by mass or more, the spinnability is not deteriorated, and if it is 28% by mass or less, a decrease in spinnability due to poor temporal stability of the spinning dope can be prevented.
In the present invention, the two types of spinning dope thus obtained are simultaneously discharged from the spinning nozzle to produce a composite fiber. The composite spinning method may be appropriately selected from known methods, but is preferably a side-by-side type composite spinning fiber.

  As described above, the acrylic fiber of the present invention discharges and solidifies two kinds of spinning dope from a side-by-side type composite spinning nozzle into a solvent-water type wet spinning bath. The solvent concentration of the spinning bath is preferably in the range of 35% by mass to 60% by mass, more preferably 40% by mass to 55% by mass. When the solvent concentration of the spinning bath is 35 to 60% by mass, DKS × DKE is in a desired range, and good anti-pill properties can be obtained. The temperature of the spinning bath is preferably in the range of 20 ° C to 45 ° C. If the temperature of the spinning bath is 20 ° C. or higher, temperature control is relatively easy, and if it is 50 ° C. or lower, workability during spinning is maintained. Further, when the temperature of the spinning bath is within this range, DKS × DKE is in a desired range, and good anti-pilling properties can be obtained.

Next, primary stretching is performed in hot water at a stretching ratio of 3 to 5 times. When the primary draw ratio is 3 times or more, it is possible to maintain a high degree of elongation required as a fiber for clothing. When the draw ratio is 5 times or less, DKS × DKE is in a desired range, and good pill properties can be obtained.
The draw ratio is more preferably 4 to 5 times.

  In order to obtain an acrylic fiber having excellent crimping properties and anti-pilling properties, which is the object of the present invention, it is necessary to perform a relaxation heat treatment in saturated steam of 90 kPa to 230 kPa, preferably 95 kPa to 170 kPa. When the vapor pressure is 90 kPa or more, good crimp characteristics can be obtained, and the dyeability is also stable. When the vapor pressure is 230 kPa or less, DKS × DKE is in a desired range, and good anti-pill properties can be obtained.

  A fiber in which fine crimps are manifested tends to cause troubles in the spinning process because of strong crimps and poor spreadability. For this reason, it is necessary to make the fine crimps latent once by secondary stretching. In the present invention, the stretching ratio of the secondary stretching may be in the range of 1.05 times to 1.20 times, preferably 1.05 times to 1.10 times. When the secondary draw ratio is 1.05 times or more, it is possible to make fine crimps latent. When the secondary stretching ratio is 1.20 times or less, excessive shrinkage is not given, and therefore it is possible to prevent deterioration of dimensional stability and texture hardening after shrinkage.

<Spun yarn>
When a spun yarn containing 30% by mass or more of the acrylic fiber produced in this way is formed, latent crimps are manifested by heat treatment such as dyeing, and a texture close to that of wool is likely to occur. Moreover, favorable anti-pill property is acquired by including 30 mass% or more of acrylic fiber of this invention.
When the acrylic fiber is 100% by mass, it is possible to obtain a knitted fabric that is excellent in bulkiness and resilience and also has good pill resistance.

In the spun yarn, fibers that can be mixed with the acrylic fibers are not particularly limited, such as synthetic fibers and natural fibers. However, in order to increase the anti-pill property, it is preferable to mix synthetic fibers having anti-pill property.
When natural fibers are mixed with the spun yarn, the anti-pill property is lowered. Therefore, the mixing ratio of natural fibers is preferably 70% by mass or less, and more preferably 30% by mass or less.
The yarn count of the spun yarn of the present invention is preferably a hair count of 60 or less. If it is 60th or less, it is preferable because the spun yarn is not too thin and it is easy to obtain bulkiness.

As for a twist coefficient, 70-120 are preferable. If it is 70 or more, the strength of the spun yarn with no problem in handling is easily obtained. If it is 120 or less, the bulkiness is easily obtained, and the texture of the knitted fabric does not become too hard.
The twist coefficient satisfies the relationship of the following formula in order to determine the number of twists from the yarn count. Number of twists (times / m) = Twist factor x √ (yarn count)
The spun yarn of the present invention preferably contains 3% to 15% by mass of conductive acrylic fiber. By including the conductive acrylic fiber in the above range, it is possible to suppress discomfort due to the generation of static electricity when the product is detached. The content of the conductive acrylic fiber is more preferably 5% by mass to 12% by mass from the viewpoint of antistatic performance and cost.

<Knitted fabric>
The knitted fabric of the present invention is a knitted fabric containing 50% by mass or more of the spun yarn. In order to maintain good anti-pill properties and easy care properties, it is preferable to use the spun yarn of the present invention as 100%, but other spinning materials are used as long as the fabric texture, anti-pill properties and easy care properties are not impaired. It is also possible to knit with yarn. The spun yarn that can be knitted is not particularly limited, such as a spun yarn made of 100% natural fiber, a spun yarn made of 100% synthetic fiber, and a spun yarn made by mixing natural fiber and synthetic fiber. In order to obtain a texture close to wool and good antipilling and easy care properties of grade 4 or higher, the knitted fabric as a whole preferably contains 30% by mass or more of the acrylic fiber of the present invention.
In addition, the dimensional change rate after repeated washing 10 times is within ± 3% in each of the vertical and horizontal directions.
Hereinafter, the present invention will be specifically described based on examples.

The physical properties and the like of acrylic fiber were measured by the following method.
If microcrimps are still latent, after pre-preparation heat treatment for 20 minutes in boiling water reveals the microcrimps, air-dry until the moisture content is 3% by mass or less, and adhere fibers to each other Open to the extent that there is no more.
(Single fiber fineness)
It measured according to the measuring method of the fineness (vibration method) of JIS L1015. In addition, 50 measurements were performed and the average value was used.

(Boiling water shrinkage)
It measured according to the measuring method of the hot-water shrinkage | contraction rate of JISL1015. The shrinkage treatment was performed in boiling water.

(Bulky)
Split 1.5 g of acrylic fiber opened to such an extent that the fibers are no longer in close contact with each other, and gently drop it into a 1000 mL measuring cylinder with a bottom area of 33.17 cm ² so that there is no gap. Fill uniformly and lower 6 g load disc into graduated cylinder. After 2 minutes, the volume v (cm ³ ) occupied by the acrylic fiber is measured, and the bulkiness is calculated by the following equation.
Bulkiness (cm ³ /g)=v÷1.5
The measurement is performed on three samples, and the average value is used.

(Crimp rate)
It measures according to the measuring method of the crimp rate of JIS L1015 (2010).

(Crimp number)
It measures according to the measuring method of the crimp number of JISL1015 (2010).

(Product of nodule strength and nodule elongation (DKS x DKE))
The nodule strength was measured according to the nodule strength (standard time test) of JIS L 1015 (2010), and the product was calculated by using the elongation at this time as the nodule elongation.

(Anti-pill property)
It measured according to the pilling test A method (ICI type | mold 5 hours) of JISL1076 (2012), and was classified into the 1st-5th grade by the fabric | texture appearance after a test.

(Dimension change rate of knitted fabric)
A test piece with a 20cm square marking on the center of a 30cm x 30cm fabric is repeatedly washed 10 times according to the JIS L 0217 103 method (hanging), and the length of each side of the square after the laundry treatment is measured. And calculated from the following equation.
Vertical dimension change rate = (20− (length of two sides in the warp direction after the washing process / 2)) / 20 × 100 (%)
Dimensional change rate in the horizontal direction = (20− (length of two sides in the horizontal direction after the washing process / 2)) / 20 × 100 (%)

(Texture)
The texture of the knitted fabric was judged by tactile sensation by 10 judges.
The determination was made according to the following criteria.
[++]: All judges were judged to have good bulkiness and resilience equivalent to wool.
[+]: 5 to 9 judges were judged to be good.
[-]: Four or fewer judges judged to be good.

[Example 1]
Copolymer A and Copolymer B shown in Table 1 were each dissolved in dimethylacetamide (DMAc) as a solvent so as to have a solid content concentration of 24% by mass to prepare a spinning dope. This spinning dope is made from a composite spinning nozzle into a side-by-side ratio of 50% by mass of copolymer A and 50% by mass of copolymer B, and is a wet spinning bath composed of dimethylacetamide (DMAc) and water at a solvent concentration of 55% and temperature of 40 ° C. Then, the mixture was discharged and solidified, and then primary stretched in hot water at a stretch ratio of 4.5 times, and then an oil agent was adhered, dried with a dry heat roller at 150 ° C., and then crimped. The obtained fiber bundle was subjected to relaxation heat treatment under saturated steam with a vapor pressure of 160 kPa to reveal the fine crimps, and then the micro-crimps were made latent once by secondary stretching with a draw ratio of 1.1 times, and spinning was performed again. After applying the crimp for use, the fiber length was cut to 51 mm to obtain a fiber having a single fiber fineness of 2.2 dtex. Using the obtained fiber, spinning was performed so that the hair count was 1/30, and after producing a tubular knitted fabric with an 18G knitting machine using the obtained spun yarn, a cationic dye (made by Hodogaya Chemical Co., Ltd .: Catillon Blue) CDRLH).
The obtained results are shown in Table 1.

[Example 2]
Fibers were obtained in the same manner as in Example 1 except that the solvent concentration, spinning bath temperature, and single fiber fineness were changed as shown in Table 1. The obtained fiber was spun and processed in the same manner as in Example 1 to produce a tubular knitted fabric and then dyed. The obtained results are shown in Table 1.

Example 3
A fiber was obtained in the same manner as in Example 1 except that the composition of the copolymer A and the single fiber fineness were changed as shown in Table 1. The obtained fiber was spun and processed in the same manner as in Example 1 to produce a tubular knitted fabric and then dyed. The obtained results are shown in Table 1.

[Comparative Example 1]
A fiber was obtained in the same manner as in Example 3 except that only the copolymer A used in Example 3 was used. The obtained fiber was spun and processed in the same manner as in Example 1 to produce a tubular knitted fabric and then dyed. The obtained results are shown in Table 1.

[Comparative Example 2]
A fiber was obtained in the same manner as in Example 1 except that only the copolymer B of Example 1 was used and the solvent concentration was changed to 30% by mass. The obtained fiber was spun and processed in the same manner as in Example 1 to produce a tubular knitted fabric and then dyed. The obtained results are shown in Table 1.

[Comparative Example 3]
The two types of copolymer A and copolymer B used in Example 1 were uniformly mixed in the state of a spinning stock solution, and then discharged and solidified from a spinning nozzle to obtain a heterogeneous polymer composite acrylic fiber. The obtained fiber was spun and processed in the same manner as in Example 1 to produce a tubular knitted fabric and then dyed. The obtained results are shown in Table 1.

[Comparative Example 4]
A fiber was obtained in the same manner as in Example 1 except that the solvent concentration was changed as shown in Table 1. The obtained fiber was spun and processed in the same manner as in Example 1, and after knitting a tubular knitted fabric, it was dyed. The obtained results are shown in Table 1.
Comparative Example 4 is a condition corresponding to the invention described in Prior Art Document 4 (Japanese Patent Laid-Open No. 59-192717).

Example 4
70% by mass of the acrylic fiber obtained in Example 1 and 30% by mass of wool (66 ′s) were blended to obtain a spun yarn having a hair count of 1/30. The obtained spun yarn was subjected to boiling water treatment at 100 ° C. for 30 minutes with a cheese dyeing machine, and then two spun yarns were aligned and a knitted fabric was produced using a 12G flat knitting machine.
The resulting knitted fabric had a texture similar to wool, had little dimensional change due to washing, and had good anti-pill properties of 4.0 grade. The results are shown in Table 2.

Example 5
40% by mass of the acrylic fiber obtained in Example 1, 30% by mass of anti-pill acrylic fiber (part number: H616, manufactured by Mitsubishi Rayon Co., Ltd.) having a single fiber fineness of 2.2 dtex, and 30% by mass of wool (66's) To obtain a spun yarn with a hair count of 1/30. The obtained spun yarn was subjected to boiling water treatment with a cheese dyeing machine in the same manner as in Example 4, and then a knitted fabric was produced using a 12G flat knitting machine.
The obtained knitted fabric had a texture similar to wool as shown in Table 2, there was little dimensional change due to washing, and the anti-pill property was as good as 4.5 grade. The results are shown in Table 2.

Example 6
90% by mass of the acrylic fiber obtained in Example 1 and 10% by mass of conductive acrylic fiber having a single fiber fineness of 3.3 dtex (product number TB10, manufactured by Mitsubishi Rayon Co., Ltd.) were blended, and the hair count was 1/30. Of spun yarn. The obtained spun yarn was subjected to boiling water treatment with a cheese dyeing machine as in Example 4, and then a knitted fabric was produced using a 12G flat knitting machine.
The obtained knitted fabric had a texture similar to wool, and as shown in Table 2, there was little dimensional change due to washing, and the anti-pill property was as good as 4.5 grade. The results are shown in Table 2.

[Comparative Example 5]
A spun yarn with 100% wool (66's) and 1/30 count hair was obtained. The obtained spun yarn was subjected to boiling water treatment using a cheese dyeing machine in the same manner as in Example 4, and then two yarns were aligned and a knitted fabric was produced using a 12G flat knitting machine.
Although the obtained knitted fabric was excellent in bulkiness and resilience, as shown in Table 2, the dimensional change caused by washing was large, and the anti-pill property was inferior to the second grade. The results are shown in Table 2.

  The acrylic fiber of the present invention has excellent crimp characteristics and anti-pilling properties, and is useful for clothing items such as sweaters and jackets, and handicraft yarns.

Claims (15)

The single fiber fineness is 1.7 to 6.6 dtex, the crimp rate measured according to JIS L1015 (2010) is 15% or more, and the bulkiness measured by the following method is 380 cm ³ / g or more. An acrylonitrile copolymer A containing 90% by mass to 95% by mass of acrylonitrile units and an acrylonitrile copolymer B containing 93.5% by mass to 97.8% by mass of acrylonitrile units in the fiber axis direction. An acrylic fiber that is composited in a side-by-side manner at an area ratio of 1: 3 to 3: 1 in the fiber cross section .
(Bulkness measuring method)
(1) Collect about 10 g of acrylic fiber cut to 51 mm and open it to such an extent that the fibers do not adhere to each other.
(2) Fractionate 1.5 g of the opened acrylic fiber.
(3) Divide into approximately 0.15 g portions, gently drop into a 1000 mL graduated cylinder with a bottom area of 33.17 cm ² and fill evenly so that there is no gap.
(4) A 6 g load disk is lowered into the measuring cylinder, and after 2 minutes, the volume vcm ³ occupied by the acrylic fiber is measured.
(5) Bulkiness is calculated by the following equation .
Bulkiness (cm ³ /g)=v÷1.5
In addition, measurement is performed on three specimens, and the average value thereof is taken as the result.   The acrylic fiber according to claim 1, wherein the single fiber fineness is 1.7 to 6.6 dtex, and the product of the knot strength (cN / dtex) and the knot elongation (%) is 10 to 25.   The acrylic fiber according to claim 1 or 2, wherein the number of crimps is 20 / 2.54 cm to 50 / 2.54 cm. Claim 1 difference value is 2 or more the content of acrylonitrile units in the copolymer A value and the content of the acrylonitrile units of the copolymer B (mass%) (mass%) Acrylic fiber. The copolymer A is a copolymer obtained by copolymerizing 90% by mass to 95% by mass of an acrylonitrile unit and 5% by mass to 10% by mass of an unsaturated monomer copolymerizable with the acrylonitrile unit. B represents 93.5% to 97.8% by mass of acrylonitrile units, 2% to 5% by mass of unsaturated monomer units copolymerizable with acrylonitrile units, and 0.2% of sulfonic acid group-containing monomer units. The acrylic fiber according to claim 4 , wherein the acrylic fiber is a copolymer obtained by copolymerization in an amount of from 1.5 to 1.5% by mass. The monomer unit contained as an unsaturated monomer unit copolymerizable with acrylonitrile in the copolymer A and the copolymer B is a vinyl acetate unit, and the sulfonic acid group-containing monomer unit is methallylsulfone. The acrylic fiber according to claim 5 , which is acid soda.   Spinning stock solution A ′ obtained by dissolving copolymer A containing 90% by mass to 95% by mass of acrylonitrile units in a solvent, and copolymer B containing 93.5% by mass to 97.8% by mass of acrylonitrile units as solvents. A method for producing an acrylic fiber by discharging a dissolved spinning solution B ′ in a side-by-side shape from a nozzle to a spinning bath having a solvent concentration of 35% to 60%, and obtaining a composite fiber, comprising the copolymer A containing an acrylonitrile unit The method for producing acrylic fiber, wherein the difference between the value of the amount (mass%) and the value of the content (mass%) of the acrylonitrile unit of the copolymer B is 2 or more. The copolymer A is a copolymer including 90% by mass to 95% by mass of an acrylonitrile unit and 5% by mass to 10% by mass of an unsaturated monomer copolymerizable with the acrylonitrile unit, and the copolymer B Is 93.5% by mass to 97.8% by mass of acrylonitrile units, 2% by mass to 5% by mass of unsaturated monomer units copolymerizable with acrylonitrile units, and 0.2% by mass to 1.% of sulfonic acid group-containing monomer units. The method for producing acrylic fiber according to claim 7 , which is a copolymer containing 5% by mass. The acrylic fiber according to claim 7 or 8 , wherein the unsaturated monomer copolymerizable with the acrylonitrile unit constituting the copolymer is vinyl acetate, and the sulfonic acid group-containing monomer is sodium methallyl sulfonate. Manufacturing method. The step of forming a composite fiber by discharging the spinning stock solution A ′ and the spinning stock solution B ′ into a spinning bath from a nozzle in a side-by-side shape, and primary stretching at a stretching ratio of 3.0 to 5.0 times The method according to any one of claims 7 to 9 , comprising a step, a step of relaxing heat treatment in saturated steam of 90 kPa to 230 kPa, and a step of performing a secondary stretching treatment at a stretching ratio of 1.05 times to 1.20 times. The manufacturing method of the acrylic fiber as described in a term. Furthermore, the manufacturing method of the acrylic fiber as described in any one of Claims 7-10 made to shrink | contract 2 to 7%. A spun yarn comprising 30% by mass or more of the acrylic fiber according to any one of claims 1 to 6 . The spun yarn according to claim 12 , comprising 3% by mass to 15% by mass of conductive acrylic fiber. A knitted fabric comprising the spun yarn according to claim 12 or 13 in an amount of 50% by mass or more and having an anti-pill property of 4th grade or more. The knitted fabric according to claim 14 , wherein the dimensional change rate after 10 times of washing is within ± 3% in each of the vertical and horizontal directions.