JP2908046B2 - Anti-pilling acrylic fiber and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acrylic synthetic fiber having excellent pilling resistance and a method for producing the same. More particularly, the present invention relates to an anti-pilling acrylic synthetic fiber having excellent texture and good post-processing properties such as spinning obtained by a dry spinning method, and a method for producing the fiber.

[0002]

2. Description of the Related Art It is well known that pilling that occurs when wearing clothing significantly impairs its aesthetic appearance or texture. In particular, since acrylic fibers have been used mainly in the field of spun knits, pilling is remarkable, and countermeasures have been strongly desired.

[0003] For this reason, various proposals have been made so far as methods for preventing the occurrence of pilling. These can be broadly classified into a method that does not generate fluff, which is the main cause of pilling, and a method that causes fluff to fall off before forming pilling even if it occurs. The former generally has poor durability in terms of pilling resistance, and has a drawback that, depending on the method, it depends on the structural aspect of the knitted fabric or the structural morphology of the fabric, so that practically widespread product development cannot be expected. In order to provide a practically advantageous anti-pilling property, the latter method, that is, a method in which the fluff is removed before the fluff is entangled and forms pilling, is effective.

As a specific method, Japanese Patent Laid-Open No.
In the fiber production process disclosed in Japanese Patent Application Laid-Open No.
Attempts have been made to reduce the strength of the fiber by imparting local defects to the fiber disclosed in the publication.
Practically desirable anti-pilling properties are not necessarily obtained by these methods, but on the other hand, on the other hand, the post-processability is deteriorated due to the decrease in fiber strength, that is, the spinning passability is poor. In the case of development, there are large defects such as generation of frying, increase in yarn spots, and reduction in strength of spun yarn, resulting in deterioration of product quality and impairment of high-order workability.

On the other hand, as a method for obtaining a fiber having a sufficient tensile strength without lowering the strength of a single fiber and having a good anti-pilling property after workability, Japanese Patent Laid-Open No. 51-102 discloses a method.
There is a technology disclosed in Japanese Patent Publication No. 120-120. According to this technique, an acrylonitrile-based polymer for forming a fiber has a composition comprising 94% or more of acrylonitrile units, 0.5 to 3.5% by weight of a strong acid group-containing monomer, and 2.5 to 5.5% by weight of another monomer. This acrylonitrile-based polymer was hot-spun 4 to 7 times after wet spinning, dried at 90 to 180 ° C. and further dried.
The content is that the film is stretched by 1 to 2.4 times and set at a fixed length at a temperature higher than the stretching temperature. This technique is a very effective method when using the wet spinning method.However, the fiber obtained by using the dry spinning method as the spinning method has a lot of flies during yarn processing, and the boiling water shrinkage of the fiber There are many points to be improved such as difficulty in dyeing due to high water content and lowering of the anti-pilling property after shrinkage in boiling water as compared with the original yarn.

In the case of acrylic fibers produced by the wet spinning method, there is a method in which the cross section of the fiber is made closer to a circle by defining the polymer composition and spinning conditions, as disclosed in JP-A-59-116409. In the case of the acrylic fiber produced by the spinning method, the excellent glossiness and the soft and bulky texture resulting from the dumbbell-shaped fiber cross-section have great characteristics, and the method of changing to the circular cross-section as described above is not applicable. hard.

[0007]

The acrylic fiber produced by the dry spinning method has a smooth structure and good transparency due to its dense structure, and has favorable characteristics as a fiber for clothing, but has poor anti-pilling properties. And is a serious cause of limiting product applications.

[0008] It is an object of the present invention to provide an acrylic fiber having excellent anti-pilling properties and excellent post-processability while making use of the preferable characteristics of the acrylic fiber obtained by the dry spinning method, and a method for producing the same.

[0009]

DISCLOSURE OF THE INVENTION The present inventors have developed a dry spinning acrylic fiber, which is widely used by consumers as a fiber for clothing, and has excellent durability and post-processability without the above-mentioned defects. The present invention has been accomplished as a result of intensive studies to obtain a pilling acrylic fiber.

That is, the present invention relates to an acrylonitrile unit of 95% by weight or more, a neutral monomer of 4% by weight or less,
Acrylonitrile polymer composed of 5% by weight of a strong acid group-containing monomer, having a tensile strength of 1.8 to 4 g / d, a product of knot strength (g / d) and knot elongation (%) of 30 or less, and boiling water An anti- pilling acrylic fiber obtained by a dry spinning method satisfying a condition of a shrinkage of -3.4 to 5% . As the neutral monomer, methyl acrylate is preferable.

Further, the method for producing an anti-pilling acrylic fiber of the present invention is characterized in that the acrylonitrile unit weighs at least 95% by weight, the neutral monomer weighs 4% by weight or less, and the strong acid group-containing monomer weighs 0.3 to 5% by weight. The spinning stock solution of the acrylonitrile-based polymer consisting of the body is dry-spun, and the fibers are subjected to primary stretching in a range of 1.2 to 5 times in hot water to hot water at 70 ° C., and then subjected to a drying and relaxation heat treatment to obtain 10 to 10%. After giving a 50% shrinkage and further performing secondary stretching in a range of 1.2 to 2.5 times at a temperature of 160 to 200 ° C. and a product of a primary stretching ratio of 3 to 8, a temperature not lower than the stretching temperature Characterized by performing a constant-length heat treatment.

The acrylic fiber obtained by the present invention has a sufficient tensile strength and elongation, does not generate fry even in a process such as spinning, and is extremely excellent in post-processability.

[0013] product of fiber of the present invention strongly that nodules (called DKS) and knot elongation (referred to as DKE) (D
KS × DKE) shows an extremely low value. The DKS × DKE value of the fiber produced by the ordinary dry spinning method is a value of 40 to 80, but the DKS × D of the fiber produced by the present invention is 40 to 80.
The KE value is 30 or less. In addition, fibers made of ordinary acrylonitrile-based polymer have a high boiling water shrinkage, or a high tensile strength even if the boiling water shrinkage is low. After the treatment with boiling water, a decrease in the anti-pill property was observed, and it was difficult to combine high tensile strength and high anti-pilling property. The present invention comprises an acrylonitrile polymer having a specific copolymer composition as described above, and a specific DKS × D
It is shown that acrylic fibers obtained by dry spinning having both high tensile strength and high anti-pilling properties can be obtained for the first time by satisfying the KE value and the boiling water shrinkage.

Hereinafter, the present invention will be described in more detail together with its operation. The acrylonitrile polymer which is the object of the present invention is 9
It is necessary to contain 5% by weight or more of acrylonitrile unit, 4% by weight or less, preferably 2% by weight or less of a neutral monomer and 0.3 to 5% by weight of a strong acid group-containing monomer. When the content of the neutral monomer exceeds 4% by weight, when a high tensile strength is imparted by stretching at a high magnification, the anti-pilling property after the boiling water treatment in the post-processing is significantly reduced, and a high anti-pilling property cannot be obtained. . When the amount of the strong acid group-containing monomer is less than 0.3% by weight, the dyeing properties are insufficient, and when it exceeds 5% by weight, staining spots and the like due to excessive dyeing properties are generated, and both are unsuitable for clothing. It is.

Specific examples of the copolymerizable neutral monomer include (meth) acrylates such as methyl acrylate and methyl methacrylate, vinyl acetate, styrene, and acrylamide. From the viewpoint of heat resistance <br/> Accession Li Le methyl it is preferable. Specific examples of the strong acid group-containing monomer include (meth) acrylic acid, (meth) allylsulfonic acid, vinylbenzenesulfonic acid and salts thereof, dimethylaminoethyl (meth) acrylate, and vinylpyridine. .

The acrylonitrile polymer used in the present invention can be produced by any conventional method such as suspension polymerization, solution polymerization and emulsion polymerization. The degree of polymerization of the polymer is preferably in the range of 0.1 to 0.2 as represented by its specific viscosity.

The stock solution for polymer spinning is prepared by dissolving the polymer in a solvent of a usual acrylonitrile polymer, for example, a solvent such as dimethylformamide, dimethylacetamide or dimethylsulfoxide so that the polymer concentration becomes 20 to 40% by weight. Although it is made, dimethylformamide is particularly preferred from the viewpoint of the solubility of the polymer and the solvent recovery.

The dry spinning method used may be a known method.
The undiluted yarn is obtained by discharging the spinning solution into high-temperature air or inert gas through an orifice to evaporate the solvent.
The undrawn yarn is temporarily drawn in a range of 1.2 to 5 times in hot water to hot water at 70 ° C. If the stretching temperature is lower than 70 ° C., sufficient stretchability and washability cannot be obtained. If the draw ratio is less than 1.2, even if the secondary draw ratio is increased, the fiber finally obtained does not have sufficient strength. On the other hand, if it exceeds 5 times, yarn breakage is likely to occur during drawing, and Stretching during stretching is less likely to occur, resulting in higher DKS and DKE, and poor anti-pilling properties.

The undrawn yarn is washed in hot water at the same time as or before and after the drawing process. Hot water temperature is 80 ~
100 ° C. is preferred. The amount of residual solvent after washing is usually less than 2%. The fiber bundle that has been subjected to the stretching cleaning treatment is then subjected to a drying and relaxation treatment. Drying usually has a surface temperature of about 115 to 15
A typical method is to pass under tension on a hot roll at 0 ° C. In this case, densification of the fiber is also achieved at the same time.

On the other hand, it is also possible to perform a relaxation heat treatment simultaneously with the drying. The yarn after hot water drawing is kept in a wet state under tension without a relative humidity of about 10 to 40% and a temperature of 110 to 160 ° C.
It is also a preferable method to perform the treatment in heated air in the range described above. As another relaxation heat treatment method, a method in which the once dried yarn is heat-treated in pressure steam at a temperature of about 100 to 140 ° C. is also simple and effective.

The relaxation heat treatment gives the fibers a shrinkage of 10 to 50%. The relaxation and shrinkage treatment imparts basic properties such as dyeability and form stability required for clothing fibers. When the shrinkage is less than 10%, sufficient dyeability is not obtained, and when the shrinkage is more than 50%, the DKS × DKE value finally decreases the anti-pilling property when passing through the subsequent process of the present invention. This is the value to be invited.

The fiber bundle which has been subjected to the drying and relaxation heat treatment is secondarily drawn 1.2 to 2.5 times at a temperature of 160 to 200 ° C. As a result, the strength of the fiber is further improved, and the permeability in the subsequent processes such as good spinning is ensured, and at the same time, the DKS
× DKE value is reduced and anti-pilling property is also improved. The secondary stretching is performed between heated hot rolls, on a hot plate or in heated steam. When the stretching temperature is lower than 160 ° C., the secondary stretchability is low, causing fluff. When the stretching temperature is higher than 200 ° C., the stretchability is reduced again, the coloring tendency of the fibers is increased, and fusion between the single fibers is caused. Value is reduced.

The desired effect can be obtained by setting the secondary stretching ratio to 1.2 or more. However, if the ratio exceeds 2.5, yarn breakage occurs frequently and stable operation cannot be achieved. Further, when the product of the primary draw ratio and the secondary draw ratio is less than 3, the tensile strength of the finally obtained fiber is insufficient and stable post-process passability cannot be secured, and if it exceeds 8, yarn breakage occurs. . The fiber must have a tensile strength of at least 1.8 g / d, and preferably at least 2.0 g / d, to ensure stable post-process permeability.
That is all.

The secondary drawn yarn is immediately subjected to a constant length treatment at a temperature not lower than its drawing temperature for several seconds to several minutes. When the constant length heat treatment is performed at a temperature lower than the drawing temperature, the boiling water shrinkage ratio of the obtained raw yarn or spun yarn becomes large, and the DK of the dyed fiber becomes higher.
The S × DKE value increases again, and the desired anti-pilling property disappears. If the DKS × DKE value exceeds 30, sufficient anti-pilling properties cannot be obtained, and even if the DKS × DKE value is 30 or less, if the boiling water shrinkage exceeds 5%, the desired anti-pilling properties cannot be obtained for the above reasons. I can't.

The fiber thus obtained is subjected to mechanical crimping as it is or appropriately, and it is led to the next step such as spinning as a staple in a tow state or cut.

The fibers of the present invention can be used alone or mixed with other synthetic or natural fibers for a wide variety of applications.

Although the basic requirements of the present invention have been described above, various other known additional conditions may be employed. For example, an inorganic compound such as titanium oxide or aluminum hydroxide, water or a non-solvent of an acrylonitrile-based polymer such as ethylene glycol may be added to the spinning dope, or the method of composite spinning or blend spinning may be applied.

[0028]

The present invention will be described below in detail with reference to examples. The "anti-pill property" was measured by the following method. JI
SIC-1076 ICI test method A (60 rpm,
5 hours), depending on the appearance change of the knitted fabric,
Class. (Hereinafter, referred to as ICI anti-pill test.) Raw cotton with good anti-pilling property means a grade of 3 or higher in the ICI anti-pill test. The knitted fabric sample used for the test was spun from raw cotton to make a # 48 single yarn and dyed cationic blue C
D. 1% using 2% owf of RLH (manufactured by Hodogaya Science)
18 knitted with boiled dyed yarn at 00 ° C for 60 minutes
A knitted fabric of 0 g / m ² was used.

Example 1 A specific viscosity of 99.4% by weight of acrylonitrile unit and 1.7% by weight of sodium methallylsulfonate unit was 0.194.
Was dissolved in dimethylformamide to prepare a stock solution having a solid content of 25%.

After heating each of the stock solutions to 130 ° C., the unstretched yarn is discharged at a spinning speed of 350 m / min from an orifice having 600 holes and a hole diameter of 0.2 mmφ into an inert gas heated to 200 ° C. Was. This undrawn yarn is bundled into a fiber bundle of 480,000 denier and drawn 1.5 to 3.6 times in hot water,
Further, after washing in hot water and applying an oil agent, the obtained fiber bundle is dried without tension at a relative humidity of 40% and a temperature of 150 ° C.
Relaxation treatment was performed. Further, after a secondary stretching of 1.5 to 2.16 times by a 200 ° C. heat roller, the tow which had been heat-set to a fixed length was given an appropriate mechanical crimp and cut into 51 mm. Table 1 shows DS, DKS × DKE value and ICI anti-pill test results of the obtained fiber.

The single fiber fineness was about 2 denier. The “specific viscosity of the polymer” was measured at 25 ° C. by dissolving the polymer in 100 ml of dimethylformamide containing 0.1 N of rhodane soda.

[0032]

[Table 1]

As shown in Table 1, the fiber obtained from the acrylonitrile-based polymer containing no neutral monomer was DKS × D
Except for the case where the KE value was high, the anti-pilling property was as good as Grade 4 in each case. When the product of the primary stretching ratio and the secondary stretching ratio (hereinafter referred to as the total stretching ratio) was low, spinning properties were poor.

Example 2 An acrylonitrile polymer having a specific viscosity of 0.141, comprising 95.0% by weight of acrylonitrile units, 4.0% by weight of methyl acrylate units and 1.0% by weight of sodium methallylsulfonate, was prepared by using dimethylformamide. And a stock solution having a solid content of 31% was prepared.

After the above stock solution was heated to 130 ° C., it was discharged from an orifice having 600 holes and a hole diameter of 0.2 mmφ into an inert gas heated to 200 ° C. to obtain an undrawn yarn. This undrawn yarn is bundled into a fiber bundle of 480,000 denier, drawn 2.5 to 3.0 times in hot water, washed in hot water and subjected to an oil agent. With no relative tension 4
Drying / relaxation treatment was performed at 0% and a temperature of 150 ° C. 2 more
After secondary stretching by 1.5 to 1.8 times with a hot roller at 00 ° C, the tow which had been heat-set to a constant length was given an appropriate mechanical crimp and cut to 51 mm. DS, DKS × D of obtained fiber
Table 2 shows the KE value and the result of the ICI anti-pill test. In addition, each single fiber fineness was about 2 denier.

[0036]

[Table 2]

COMPARATIVE EXAMPLE 1 An acrylonitrile polymer having a specific viscosity of 0.161, comprising 93.5% by weight of acrylonitrile unit, 6.0% by weight of methyl acrylate unit and 0.5% by weight of sodium methallylsulfonate, was prepared by using dimethylformamide. And a stock solution having a solid content of 30% was prepared.

After the above stock solution was heated to 130 ° C., it was discharged through an orifice having 600 holes and a hole diameter of 0.2 mmφ into an inert gas heated to 200 ° C. to obtain an undrawn yarn. This undrawn yarn is bundled into a fiber bundle of 480,000 denier, drawn in hot water by a factor of 2.25 to 3.33 times, and further washed in hot water and subjected to an oil agent. Drying / relaxation treatment was performed at a relative humidity of 40% and a temperature of 150 ° C. under no tension. Further, after secondary stretching by 1.5 to 2.0 times with a 200 ° C. heat roller, the tow which had been heat-set at a fixed length was given an appropriate mechanical crimp and cut to 51 mm. DS, DKS of the obtained fiber
Table 3 shows the × DKE value and the results of the ICI anti-pill test. In addition, each single fiber fineness was about 2 denier.

[0039]

[Table 3]

As shown in Table 3, the fiber obtained from the acrylonitrile polymer having a high copolymerization ratio of the neutral monomer was D
Although the KS × DKE value was low, the anti-pilling property was poor, ie, the first and second grades.

[0041]

As is clear from the above description, the present invention
The present invention provides an acrylic fiber having high tensile strength and high pilling resistance, which cannot be obtained with an acrylic fiber obtained by a conventional dry spinning method, and a method for producing the same. Since the good texture of the system fiber is not impaired and pilling does not occur, it can be expected to be widely applied to clothing such as underwear, and its industrial significance is great.

[0042]

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshinori Furuya 20-1 Miyukicho, Otake City, Hiroshima Prefecture Mitsubishi Rayon Co., Ltd. Otake Works (56) References JP-A-57-143513 (JP, A) 1986-12909 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) D01F 6/18, 6/38

Claims (3)

(57) [Claims] 1. An acrylonitrile polymer comprising 95% by weight or more of acrylonitrile units, 4% by weight or less of a neutral monomer and 0.3 to 5% by weight of a strong acid group-containing monomer, having a tensile strength of 1.8. ~ 4 g / d, nodule strength (g /
the product of d) and knot elongation (%) is 30 or less, boiling water shrinkage -
An anti-pilling acrylic fiber obtained by a dry spinning method satisfying a condition of 3.4 to 5% . 2. The acrylic fiber according to claim 1, wherein the neutral monomer is methyl acrylate. 3. A spinning stock solution of an acrylonitrile-based polymer comprising 95% by weight or more of acrylonitrile units, 4% by weight or less of a neutral monomer and 0.3 to 5% by weight or more of a strong acid group-containing monomer. The fiber is spun and the fiber is subjected to primary stretching in a range of 1.2 to 5 times in hot water at 70 ° C. to hot water, followed by drying and relaxation heat treatment to give a shrinkage of 10 to 50%, and a temperature of 160 to 200%. 2. The composition is subjected to a second stretching in a range of 1.2 to 2.5 times at 1C and a product of a primary stretching ratio of 3 to 8 and then to a constant-length heat treatment at a temperature not lower than the stretching temperature. A method for producing the anti-pilling acrylic fiber according to the above.