JP2000178829A - Polyphenylene sulfide fiber and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To industrially and efficiently produce polyphenylene sulfide fibers excellent in fiber characteristics such as strength and scarcely causing defects such as fuzz or unevenness of denier. SOLUTION: The characteristic of the polyphenylene sulfide fibers is to have <=1.2 unevenness of denier (URi) and <=6.0%; dry heat shrinkage percentage at 160 deg.C. The polyphenylene sulfide fibers are produced by melting a polyphenylene sulfide polymer, then extruding the molten polymer through a spinneret, winding the extruded fibers at >=1,000 m/min speed, subsequently hot drawing the fibers without winding the fibers once and then carrying out the relaxing heat treatment at 160-240 deg.C temperature and 1-10% relaxing ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyphenylene sulfide fiber having heat resistance and chemical resistance, and a method for producing the same. The present invention relates to a polyphenylene sulfide fiber having few disadvantages and a method for industrially efficiently producing such a fiber.

[0002]

2. Description of the Related Art Fibers made of polyphenylene sulfide polymer have excellent properties such as heat resistance, oxidation resistance, flame resistance, and chemical resistance. It is expected as a fiber material used under severe environmental conditions such as clothes. Various techniques have been conventionally proposed for such polyphenylene sulfide fiber production methods.

For example, Japanese Unexamined Patent Publication (Kokai) No. 57-143518 discloses a method of forming a fiber by applying a multi-stage hot drawing method employed for drawing polyester terephthalate or nylon 6 or 66 to an undrawn yarn made of polyphenylene sulfide. In Japanese Patent Application Laid-Open Nos. 58-20447 and 60-115559, it is possible to suppress the gelation in the melt spinning process by adding a stabilizer to the polymer, It is disclosed that a fiber excellent in the above is obtained. Also, Japanese Patent Application Laid-Open No. 61-1528
No. 28 discloses a method in which an oil agent containing a specific smoothing agent component is applied to spun yarn to prevent fluff and yarn breakage during the drawing process.

[0004]

However, any of the above-mentioned conventional methods for producing polyphenylene sulfide fiber does not improve the generation of fluff or breakage during spinning and drawing, and often involves a decrease in productivity. This has the problem. Therefore, there are few proposals for production technologies that combine high physical properties with high productivity. At present, the technology is different from the spinning and drawing technologies of general-purpose polymers such as polyester fibers and polyamide fibers. Is clear. Therefore, today, it is expected to establish a yarn-making technique capable of dramatically improving productivity without sacrificing the excellent fiber properties of polyphenylene sulfide.

[0005]

The present invention adopts the following means in order to solve the above-mentioned problems of the prior art. That is, in the present invention, the denier spot (URi) is less than 1.2,
After melting the polyphenylene sulfide fiber and the polyphenylene sulfide polymer whose dry heat shrinkage at 0 ° C. is 6.0% or less, spinning through a spinneret and winding at a speed of 1,000 m / min or more, A method for producing a polyphenylene sulfide fiber, which comprises performing hot stretching once without winding, and then performing relaxation heat treatment at a temperature of 160 to 240 ° C. at a relaxation rate of 1 to 10%. More specifically, the method for producing polyphenylene sulfide fiber described above, wherein the hot drawing is performed in multiple stages, and the polyphenylene sulfide polymer has a weight average molecular weight (Mw) of 20,000 to 100,000 and a molecular weight distribution (Mw). / Mn) is 10 or less, and the weight-average molecular weight of the oligomer is 1,000 or less. The weight fraction of the oligomer is 5% or less.

Hereinafter, the present invention will be described in detail. First, the polyphenylene sulfide polymer according to the present invention preferably has a weight average molecular weight (Mw) of 20,000 to 100,000. Weight average molecular weight (Mw) of 20,000
When the melt spinning was performed using a polyphenylene sulfide polymer of less than 10%, the spinning tension was low, so that the spinning and drawing state became unstable, yarn breakage was likely to occur during spinning and drawing, and the spinning stability was reduced. This is because the mechanical properties of the polyphenylene sulfide fiber are also inferior. On the other hand, when a polyphenylene sulfide polymer having a weight average molecular weight (Mw) of more than 100,000 is used, the viscosity of the solution becomes high, and a special spinning device with high pressure resistance is required for fiberization by the melt spinning method. This is because the production method is unsuitable for the direct spinning method employed in the present invention. Preferably it is 40000-80000.

Further, in addition to the weight average molecular weight (Mw), the molecular weight distribution (Mw / Mn) is also an important factor affecting the stability of spinning and drawing. If the molecular weight distribution of the polyphenylene sulfide polymer exceeds 10, yarn breakage is likely to occur in the process of drawing and thinning, and the stability is reduced. It is desirable that the molecular weight distribution is small from the viewpoint of stability such as yarn breakage during spinning and stretching, but it is needless to say that the molecular weight distribution is appropriately set in consideration of polymerization technology and cost. Preferably it is 1.1-5.0.

The amount of oligomer contained in the polyphenylene sulfide polymer is desirably 5% or less by weight of the oligomer having a weight average molecular weight of 1,000 or less contained in the polymer. When the weight fraction of the oligomer having a weight average molecular weight of 1,000 or less is larger than 5%,
This is because yarn breakage and fluff in the spinning and drawing section are likely to occur, and safety is reduced.

The polyphenylene sulfide referred to in the present invention
The polymer is represented by the general formula-(RS) _nPolymerization represented by-
Body. Where R is a phenylene group, a biphenylene group,
Biphenylene ether group, naphthalene group, diphenylke
Represents an aromatic group such as a ton group, and a part or all of R
These lower alkyl group-substituted derivatives may be part of or
The whole may be sulfonated.

[0010] The direct spinning method of the present invention is performed at 1000 m /
Winding at a speed of more than one minute
Thereafter, relaxation heat treatment is performed. At this time, the relaxation rate is 1 to
It is preferable to carry out in the range of 10%. If the spinning speed is 1,
If it is less than 000 m / min, the yarn tension during spinning decreases,
In addition to increasing denier spots in the longitudinal direction of the yarn,
Production efficiency is undesirably reduced. Preferably 1000 to
1500 m / min.

The thermal stretching is preferably performed in multiple stages of two or more stages, but considering the cost of equipment and the like, the number of stretching stages is preferably as small as two or three as long as the spinning properties are allowed. Specifically, for example, in the case of two-stage stretching, the first stage is 70 to 110 ° C.,
The second stage is preferably stretched at a temperature of 180 to 250 ° C.

According to the present invention, after heat stretching, relaxation heat treatment is performed between the final rollers. Roller temperature is
160-240 degreeC and the relaxation rate have a preferable range of 1-10%. If the relaxing roller temperature is lower than 160 ° C., the expected relaxing effect cannot be obtained.
If the temperature is higher than 0 ° C., undesirably, the spinning properties and the quality of the fibers are reduced due to interference between the yarns on the roller. Further, when the relaxation rate is less than 1%, the generation of fluff increases,
On the other hand, if the yarn breakage occurs more frequently than 10%, the interference between the yarns will increase, and the generation of fluff will increase. The relaxation rate is more preferably 2 to 8%.
Is good in terms of the spinning properties and quality.

[0013] The polyphenylene sulfide fiber obtained by the above method has higher productivity than the fiber obtained by the conventional FDY method, as well as denier spots (UR).
i) is 1.2 or less, preferably 1.0 or less, and it is possible to obtain a high-quality fiber with very little fluff. Furthermore, the dry heat shrinkage at 160 ° C. is significantly reduced (160 ° C.
(The dry heat shrinkage rate is 6.0% or less, preferably 5.0% or less), and it has become possible to provide a fiber having excellent dimensional stability.

[0014]

EXAMPLES The present invention will be specifically described below with reference to examples, but the measuring method used in the present invention will be described. [160 ° C. dry heat shrinkage]: Measured under the following conditions in accordance with JIS-L-1013. After the sample was left in an atmosphere of 20 ° C. and 65% RH, a 1/30 g / d load was applied to the yarn, and the yarn length was measured to be 50 cm. 160 ° C, 30
After a dry heat treatment for 1 minute, the yarn length was measured under the same load as before the treatment, and the average of three times calculated by the following formula. (Yarn length difference before and after dry heat treatment) / 50 cm × 100 [Productivity]: ○ Little yarn breakage is observed. △ Thread breakage occurs slightly. × Thread breakage occurs frequently. [Quality]: ○ Excellent quality without fuzz. △ Some fluff. × Less fluff and poor quality. [Strong elongation]: Test length 250 according to JIS L1013
mm and a tensile speed of 300 mm / min. [URi]: Worster fluctuation rate of 100 m of yarn length was measured using a wrister measuring device UT-1 (Tsul Vega Worster). The sample speed was 50 m / min, the recorder speed was 2.5 m / min, and the range was ± 12.5%. The obtained chart is divided into two parts, and the highest point (H)
And the lowest point (L) were read and calculated by the following equation. URi = 0.5 ｛(H1 + H2) / 2 + (L1 + L2)
/ 2｝

(Examples 1 to 4, Comparative Examples 1 to 5) Mw 53
000, Mw / Mn 3.0, oligomer weight fraction 3.7
% Of the polyphenylene sulfide polymer was melted by a conventional method, and the yarn discharged at a spinning temperature of 290 ° C. was 0.3 m / m.
Polyphenylene sulfide filaments were produced under a variety of stretching / relaxation treatment conditions shown in Table 1 directly after cooling and solidifying in a cooling airflow for 2 seconds. Table 1 shows the results of the obtained filaments. (Comparative Example 6) The same polyphenylene sulfide polymer as in Example 1 was melted by a conventional method, and the yarn discharged at a spinning temperature of 290 ° C was exposed to a cooling airflow of 0.3 m / sec. At a take-up speed of Then 2.
It was drawn 7 times to produce 218 denier 60 filament polyphenylene sulfide filament. Table 1 shows the results of the obtained fibers.

[0016]

[Table 1]

(Examples 5 to 9) The polymers shown in Table 2 were melted by a conventional method, and the yarn discharged at a spinning temperature of 290 ° C. was exposed to a cooling air flow of 0.3 m / sec. , 0
The film was taken up at 00 m / min, stretched in two steps without being wound up once, and wound up at a speed of 3,000 m / min. Table 2 shows the results of the obtained polyphenylene sulfide filaments.

[0018]

[Table 2]

[0019]

According to the present invention, it has become possible to achieve a technique for industrially stably producing high-quality polyphenylene sulfide fibers having high physical properties and high quality, which has been conventionally difficult.

Claims (4)

[Claims] (1) a denier spot (URi) of 1.2 or less;
A polyphenylene sulfide fiber having a dry heat shrinkage at 60 ° C. of 6.0% or less. 2. After the polyphenylene sulfide polymer is melted, it is spun through a spinneret, wound up at a speed of 1,000 m / min or more, then hot stretched once without being wound up, and then at a relaxation rate of 1 to 10%. A method for producing polyphenylene sulfide fiber, wherein a relaxation heat treatment is performed at a temperature of 160 to 240 ° C. 3. The method for producing polyphenylene sulfide fiber according to claim 1, wherein the hot drawing is performed in multiple stages. 4. An oligomer having a weight average molecular weight (Mw) of 20,000 to 100,000, a molecular weight distribution (Mw / Mn) of 10 or less, and a weight average molecular weight of 1,000 or less in the polyphenylene sulfide polymer. The method for producing polyphenylene sulfide fiber according to claim 1, wherein the rate is 5% or less.