JP5161455B2 - Acrylic fiber with anti-pill performance - Google Patents

Description

    The present invention relates to an anti-pill acrylic resin having excellent anti-pill properties and flexibility, and good quality and performance, and a method for producing the same.

    Acrylic fibers have a soft texture, bulkiness and excellent dyeability similar to wool compared to other synthetic fibers, and are used for clothing and interiors. There is a practical problem that pills called pilling intertwined with each other tend to occur, the appearance of the fiber is remarkably impaired, and the commercial value is lowered. On the other hand, in recent years, in order to make the texture of clothing use even softer, the fineness of the fibers has been advanced, and product development using fine fiber has been carried out. At present, there is a tendency to occur easily, and the demand for improving the anti-pill property is increasing.

For improving the anti-pill performance of acrylic fibers from the past, for example, as disclosed in Patent Document 1, a method of reducing the strength of the fiber by adopting stretching at a low stretch ratio in the fiber manufacturing process, As disclosed in Patent Document 2, there has been proposed a method of reducing the strength of a fiber by imparting a local defect to the fiber. However, according to these methods, although the anti-pill property is improved, there is a problem in the processing process passability such as frequent fly in the spinning process. Further, Patent Document 3 discloses an anti-pill acrylic fiber having a fineness having a knot strength and a circularity index of a specific single fiber. Although the anti-pill property is improved, the obtained spinning The yarn did not swell, and the fabric obtained from the anti-pill acrylic resin lacked softness. On the other hand, as a fiber excellent in flexibility, it is known that the fiber cross-sectional shape is a dumbbell cross section, an elliptical cross section or a flat cross section, but a fabric obtained from such a fiber is excellent in flexibility, An acrylic fiber having a low anti-pill property and satisfying both flexibility and anti-pill property has been desired.

JP-A-57-121610 JP-A-56-128324 Japanese Patent Laid-Open No. 09-250024

    It is an object of the present invention to provide an anti-pill fine acrylic fiber and to provide an acrylic fiber having excellent flexibility and anti-pill properties.

The gist of the present invention is an acrylic fiber comprising an acrylic polymer containing 90% by mass or more of an acrylonitrile unit, which satisfies the following (1), (2) and (3): It is in.
(1) The single fiber fineness is 0.3 to 2.0 dtex, the tensile strength is 2.0 cN / dtex or more,
The nodule strength is 0.8 to 1.7 cN / dtex.
(2) When the fiber cross-sectional shape is flat and the cross-sectional area of the rectangle represented by the product of the maximum value A of the long axis and the maximum value B of the short axis in the fiber cross-section is S, and the cross-sectional area of the fiber itself is S1 The area ratio S1 / S satisfies 0.53 <S1 / S ≦ 0.75 .
(3) The crimp rate after boiling water treatment is 3% or less.

  INDUSTRIAL APPLICABILITY The present invention provides an acrylic ultrafine fiber having excellent flexibility and anti-pilling properties, and can be suitably used for clothing items such as sweaters, jerseys, and underwear.

    The acrylic fiber of the present invention contains 90% by mass or more of an acrylonitrile unit and is formed from an acrylonitrile-based polymer composed of an unsaturated monomer unit copolymerizable with acrylonitrile. The preferred content of the acrylonitrile unit is 90 to 95% by mass. If the acrylonitrile unit is less than 90% by mass, sufficient tensile strength cannot be obtained, resulting in poor practicality. If it exceeds 95% by mass, the dyeability deteriorates, which is not preferable. Examples of unsaturated monomers copolymerizable with acrylonitrile include acrylic acid, methacrylic acid, or alkyl esters thereof, vinyl acetate, acrylamide, vinyl chloride, vinylidene chloride, and depending on the purpose, sodium vinylbenzene sulfonate and methallyl. Ionic unsaturated monomers such as sulfonic acid soda and acrylamide dimethyl propane sulfosoda can be used.

  The anti-pill acrylic resin of the present invention has a single fiber fineness of 0.3 to 2.0 dtex, preferably 0.5 to 1.7 dtex. If the single fiber fineness exceeds 2.0, a soft texture cannot be imparted to the fiber product, and if it is less than 0.3 dtex, spinning is difficult, which is not preferable.

  The tensile strength of the anti-pill acrylic fiber of the present invention needs to be 2.0 cN / dtex or more in order to withstand practicality such as passing through a spinning process. When the tensile strength is less than 2.0 cN / dtex, the fiber is frequently cut in the spinning process, and when the obtained yarn is knitted, workability such as frequent yarn breakage becomes unfavorable.

  The knot strength of the anti-pill acrylic fiber of the present invention is required to be 0.8 to 1.7 cN / dtex. If it is less than 0.8 cN / dtex, flies frequently occur in the spinning process, resulting in poor practicality. If it exceeds 1.7 cN / dtex, the bending strength becomes high and the anti-pill property becomes insufficient, which is not preferable.

The fiber cross-sectional shape of the anti-pill acrylic fiber of the present invention is flat, and the cross-sectional area of the rectangle represented by the product of the maximum value A of the long axis and the maximum value B of the short axis in the fiber cross section is S, fiber When the sectional area of itself is S1, the area ratio S1 / S (hereinafter abbreviated as sectional parameter) needs to be 0.53 <S1 / S <0.95. When S1 / S is 0.53 or less, the unevenness of the cross section increases and the single fibers are easily caught between each other. Therefore, a soft texture cannot be given to the obtained fabric, and the sharpness is increased. Absent. On the other hand, if S1 / S is 0.95 or more, an edge is present in the fiber cross section, and the single fibers are likely to be caught with each other, so that a soft texture cannot be given and the sharpness increases, which is not preferable. In either case, the anti-pill property is insufficient, which is not preferable.

  The anti-pill acrylic fiber of the present invention is required to have a crimp rate of 3% or less after boiling water treatment. If the crimping rate after boiling water treatment exceeds 3%, the acrylic fiber crimps recur and increase in the processing step such as dyeing, and the acrylic fibers are easily entangled with each other. This is not preferable because the anti-pilling property of the resin significantly decreases.

  Examples of the solvent of the acrylonitrile polymer used for the production of the anti-pyracrylic fiber of the present invention include organic solvents such as dimethylacetamide, dimethylformamide, and dimethylsulfoxide, concentrated inorganic salts such as nitric acid, sodium rhodanate, and zinc chloride. Although an aqueous solution is mentioned, it is desirable to use an organic solvent because the cross-sectional shape of the fiber can be easily controlled.

  The anti-pill acrylic fiber of the present invention can be fiber-shaped by a wet spinning method or a dry-wet spinning method, but the wet spinning method is desirable in terms of controllability of the fiber cross-sectional shape. An spinning polymer solution is prepared by dissolving an acrylic polymer containing 90% by mass or more of acrylonitrile units in an organic solvent at 50 ° C. Regarding the melting temperature, when the temperature is low, the amount of undissolved component increases, and accordingly, the filter medium such as a filter press is preoccupied quickly and the spinnability is impaired. On the other hand, when the dissolution temperature is high, the polymer is discolored, so 70 ° C. or lower is preferable. The solid concentration of the spinning dope is preferably 15 to 30% by mass. If it is 15% by mass or less, the production is remarkably reduced and the tensile strength is further reduced. On the other hand, if it is 30% by mass or more, the gloss of the fiber is lowered.

  In the present invention, the spinning dope is extruded from a spinneret into a coagulation bath composed of water and a solvent and coagulated into fibers. At this time, the solvent concentration is set to 20 to 60% by mass and the solvent temperature is set to 30 to 60 ° C., preferably the solvent concentration is 25 to 55% by mass and the solvent temperature is 35 to 50 ° C. When the solvent concentration is 20% by mass or less, uniform coagulation does not proceed and spinnability is deteriorated. If it exceeds 60% by mass, fiberization in the coagulation bath is delayed, and adhesion between the fibers is likely to occur. When the solvent temperature is 30 ° C. or lower, the spinnability is lowered. On the other hand, when the temperature exceeds 60 ° C., solidification in the spinning bath is accelerated and the tensile strength of the fiber is lowered. The spinning draft is in the range of 0.4 to 2.0, preferably 0.6 to 1.8. When the spinning draft exceeds 2.0, the fibers spun on the base surface are frequently cut, which is not preferable. Further, when the spinning draft is 0.4 or less, it becomes difficult to make the fiber cross-sectional shape dumbbell, oval or flat, which is not preferable. Further, since the cross-sectional parameter S1 / S of the anti-pill acrylic fiber is 0.53 <S1 / S <0.95, the solvent concentration of the coagulation bath is 20 to 60% by mass, and the solvent temperature is 30 to 60 ° C. It is preferable to set to.

  The yarn spun and fiberized in the coagulation bath is subjected to primary heat drawing at a draw ratio of 4 to 7 times under wet heat, and then subjected to wet heat relaxation treatment. The moist heat relaxation treatment is performed in a moist heat atmosphere at 100 to 130 ° C., and it is preferable to set the temperature condition so that the moist heat relaxation shrinkage rate of the yarn is 10 to 20%. When the wet heat relaxation shrinkage rate of the yarn exceeds 20%, the anti-pilling property of the resulting acrylic fiber is unfavorable. On the other hand, when it is less than 10%, the dyeability becomes poor.

  After the wet heat relaxation treatment is performed, it is necessary to further perform the second stretching treatment. The second stretching treatment can be performed by stretching in hot water, stretching between rolls between dry heat rolls, and wet heat stretching in saturated steam. The secondary stretching is a treatment for improving the anti-pilling property, and by performing the stretching treatment at a specific stretching ratio and stretching temperature condition, the stress inside the fiber is relaxed in a state where the acrylic fiber is stretched. Therefore, selectively reducing the knot strength and preventing recurrence of crimp due to internal stress factors during post-dry heat processing such as dyeing of the acrylic fiber and dry heat roller contact treatment, Mechanical crimps imparted to the acrylic fibers described later can be easily removed, and the entanglement between the fibers is reduced, so that the anti-pill property can be remarkably improved. The conditions for the draw ratio are preferably set to 1.1 to 1.4 times. In order to relieve the internal stress of the acrylic fiber reliably, it is preferably 1.1 times or more, and preferably 1.4 times or less so that the acrylic fiber is not partially broken and the strength is not lowered. . The stretching temperature is preferably set to 130 ° C. or higher for wet heat and 200 ° C. or higher for dry heat. If the wet heat is less than 130 ° C. or the dry heat is less than 200 ° C., the stress due to the second stretching is accumulated in the acrylic fiber, so the crimp rate after the boiling water treatment which is a requirement of the present invention is 3% or less. This is not preferable because it cannot be achieved, and the wet heat treatment in the processing such as dyeing causes recurrence and increase of the crimp of the acrylic fiber, and the anti-pilling property of the fabric using the acrylic fiber is remarkably lowered.

  In addition, the order and the number of times of wet heat relaxation and secondary stretching are not limited to the above-mentioned examples, and after the secondary stretching following the primary stretching, the wet heat relaxation treatment may be performed, After the first stretching, the wet heat relaxation treatment and / or the second stretching can be repeatedly performed or the order thereof can be changed. However, in the case where wet heat relaxation treatment and / or secondary stretching is performed a plurality of times, it is possible to gradually increase the treatment temperature of the secondary stretching relative to the treatment temperature of the previous stage to increase the internal stress inside the acrylic fiber. It is preferable in terms of suppressing generation, that is, achieving a crimp rate of 3% or less after boiling water treatment.

  In order to improve the handleability of the fiber tow and the passability during spinning, mechanical crimping is appropriately imparted by a normal method. When applying mechanical crimping, it is carried out in a humid heat atmosphere, but it is necessary to carry out the wet heat temperature at less than 100 ° C. When the wet heat temperature is 100 ° C. or higher, the wet heat is set in a state where the acrylic fiber is crimped, and the crimp rate after boiling water treatment cannot be 3% or less, which is not preferable. Furthermore, with respect to anti-pills, it is desirable that low crimps or crimps be easily removed in order to suppress contact between single fibers, such as reduction of wet heat relaxation time, improvement of stretch ratio and stretch temperature, relaxation of crimper conditions, etc. You may adjust it.

The anti-pill acrylic fiber of the present invention obtained by the above production method is cut into short fibers and then spun. The composition of the spun yarn may be 100% of the anti-pill-resistant acrylic fiber of the present invention, and other fibers, for example, synthetic fibers such as ordinary acrylic fibers, polyester fibers, nylon fibers, rayon fibers or chemical fibers, It can also be blended with natural fibers such as cotton, wool and silk to make spun yarn.

Hereinafter, the present invention will be described more specifically with reference to examples.
In addition, the characteristic value shown in the Example of this invention was measured with the following method.
(Measurement method of crimp rate after boiling water treatment)
The tow was kept in boiling water for 30 minutes and then taken out. The water was sufficiently wiped off with filter paper and air-dried for 20 hours, and then the crimp rate was measured according to JIS L 1015.
(Fiber adhesion evaluation method)
A card web obtained by passing 5 g of a fiber cut to 51 mm once through a miniature card (manufactured by Daiwa Kikko KK, model number S8D) is visually observed. X.
(Spinning passability evaluation method)
When spinning a 1/52 metric spun yarn using fibers cut to 51 mm, with a 200 spindle spinning machine, the state of fly generation during 2 Doff spinning was visually observed by five subjects, A score of 1 was given for good and 0 was given for bad, and the following was determined from the total of the results of 5 people.
○: Less (3 to 5 points), ×: More (0 to 2 points)
(Texture evaluation method)
The following knitted fabric for measuring anti-pill property was prepared and touched by the surface of the knitted fabric by 5 subjects, and scored 5 points for good, 1 for normal, and 0 for bad. From the total of the results, the determination was made as follows.
○: Soft and good (7-10 points), △: Normal (4-6 points)
X: It is bad and it is bad (0 to 3 points)
(Anti-pill evaluation method)
Acrylic fiber is cut to 51 mm, and a 1/52 metric yarn is spun by 2-inch spinning. Using this spun yarn, it is knitted into a tengu structure using a 48 gauge, 48 circular knitting machine. Created the ground. The resulting knitted fabric is dyed with 0.2% owf Aizen Cathilon Blue-BRLH dye solution manufactured by Hodogaya Chemical Co., Ltd. under a bath ratio of 1: 100, a temperature of 97 ° C., and a time of 50 minutes, and then heated at 60 ° C. After drying with a dryer, a knitted fabric for measuring the anti-pill property was prepared, and the anti-pill property was evaluated by the ICI method (tested for 5 hours by JIS L 1076 A method).

(Examples 1-5, Reference Example 1, Comparative Examples 1-11)
An acrylic polymer having an AN content shown in Table 1 was used, and dimethylacetamide was used as a solvent to prepare 1.1 dtex acrylic fibers. Examples 3 to 5 and Comparative Examples 6 and 7
9-11 were obtained by further processing the obtained acrylic fiber as described in the column of the additional processing step. For example, Example 3 is the acrylic type obtained in Example 1. The fiber was subjected to the second stretching and wet heat relaxation under the conditions described in Table 1, and Example 4
The acrylic fiber obtained in Example 3 is subjected to the second stretching treatment under the conditions shown in Table 1. The results of evaluating these acrylic fibers are shown in Table 2. From this, it was found that the anti-pill acrylic fiber according to the present invention is excellent in fiber production, spinning operation, fiber physical properties and anti-pill properties.

(Examples 7-9, Comparative Examples 12-15)
After crimping the tow-shaped acrylic fibers produced in Example 1 and Comparative Examples 1 and 2 and cutting them to a length of 51 mm, cotton or rayon and blended cotton and spun yarn were used in the proportions shown in Table 2, and a tengu structure The knitted fabric was knitted, dyed, and evaluated for anti-pill property by the ICI method (5 hours). As is apparent from the results in Table 3, it was found that the fabric produced by spinning the acrylic fiber of the present invention has excellent anti-pill properties and texture.

Claims (1)

An anti-pill acrylic fiber satisfying the following (1), (2) and (3), which is an acrylic fiber made of an acrylic polymer containing 90% by mass or more of acrylonitrile units.
(1) The single fiber fineness is 0.3 to 2.0 dtex, the tensile strength is 2.0 cN / dtex or more,
The nodule strength is 0.8 to 1.7 cN / dtex.
(2) When the fiber cross-sectional shape is flat and the cross-sectional area of the rectangle represented by the product of the maximum value A of the long axis and the maximum value B of the short axis in the fiber cross-section is S, and the cross-sectional area of the fiber itself is S1 The area ratio S1 / S satisfies 0.53 <S1 / S ≦ 0.75 .
(3) The crimp rate after boiling water treatment is 3% or less.