JPH01239126A - Highly crimped and low-shrinkable staple fiber - Google Patents

Abstract

PURPOSE:To obtain a highly crimped and low-shrinkable staple fiber, consisting of a polyarylene sulfide having respective specific birefringence ratio, number of crimps, percentage crimp and dry heat shrinkage factor and excellent in strength, heat and chemical resistance and dimensional stability. CONSTITUTION:A staple fiber, obtained by spinning a polymer prepared by reacting a polyhalo-substituted cyclic compound having an unsaturated group between adjacent ring atoms with an alkaline metal sulfide in an organic polar solvent and having groups -R-S- (R is preferably phenylene) as recurring units, drawing the resultant fiber and heat-treating the drawn fiber, having 0.150-0.300, preferably 0.200-0.250 birefringence ratio, >=10 crimps/25mm, preferably 10-15 crimps/25mm number of crimps, >=10%, preferably 10-15% percentage crimp and <=3% dry heat shrinkage factor at 160 deg.C and suitable as industrial filters, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a novel high crimping/low shrinkage staple fiber made of polyarylene sulfide (hereinafter referred to as PAS).

[Prior Art] Conventional staple fibers made of thermoplastic polymers such as polyesters and polypropylenes are produced in high quality through processes such as spinning, drawing, curling, and cutting. ing.

However, in recent years, with the progress of polymerization technology, new polymers with excellent properties have been created and production technology has been developed.As for PAS, one of them, the cost of raw materials has been reduced, and fiberization is being considered. being done. P
Fibers made of AS have excellent properties such as heat resistance, oxidation resistance, flame resistance, and chemical resistance, so they are promising as materials for textile products used under harsh conditions such as industrial filters and protective clothing. It has been known.

Regarding PAS fiberization technology, for example, Japanese Patent Publication No. 52-36
No. 09, JP-A-57-143518, JP-A No. 58-311
No. 12 and other publications, but all of these had woody defects such as lack of dimensional stability, and the resulting fibers were rigid and brittle, making them unsuitable for crimping. . Furthermore, since the fiber surface is smooth and has electrostatic properties, it is difficult to handle it, and various troubles tend to occur during various processes after fiberization, such as spinning and knitting techniques, to finish it as knitting, woven fabric, and non-woven fabric. There was a problem.

[Problems to be Solved by the Invention] In view of the above circumstances, the present invention provides a material that has high dimensional stability, high crimpability, and low shrinkage even if it is made of PAS,
In addition, we studied how to obtain excellent staple fibers that do not cause various troubles in various steps after fiberization.

[Means for Solving the Problems] The present invention capable of solving the above problems consists of PAS, Birefringence: 0.150 to 0.300 Number of crimp = 10 or more / 25 mm Ratio of crimp: 10 % or more and dry heat (160° C.) shrinkage rate = 3% or less.

[Function] In the present invention, PAS refers to one R-S- group ( Tatashi R: A polymer having as a repeating unit phenylene, biphenylene, naphthalene, biphenylene ether, or a lower alkyl-substituted derivative thereof having 1 to 6 carbon atoms, typically as described in US Pat. No. 3,354,129. Although those detailed in the book can be used, everything that falls within the scope of PAS is included in the scope of the present invention. In the present invention, polyphenylene sulfide (hereinafter referred to as PPS) in which R is a phenylene group is particularly preferred.

The high crimping/low shrinkage staple fiber of the present invention has a birefringence of 0.150 to 0.300, particularly preferably 0.150 to 0.300.
It is in the range of 200 to 0.250. When the birefringence is within the range of 0.150 to 0.300, a sufficient degree of fiber orientation can be obtained, and physical properties such as toughness as a staple fiber, specifically strength of 3.5 g/d or more and elongation of 30% or more are obtained. can be obtained, resulting in good passability in subsequent processes. Outside the above range, not only will the strength and elongation necessary for staple fibers not be obtained, but there will also be a drawback of a lack of dimensional stability.

Furthermore, in the highly crimped/low shrinkage staple fiber of the present invention, the number of crimps is 10 or more/25 mm, preferably 10 to 25 mm.
15 pieces/25+nm, crimp ratio: 10% or more, preferably 1
0 to 15%, dry heat shrinkage measured at 160°C: 3% or less. If the number of crimps is less than 10/25 mm and the crimping rate is less than 10%, the fibers will not be crimped enough and the interlacing between the fibers will not be sufficient, causing problems such as wrapping in the subsequent process, such as the carding process. cause In addition, if the dry heat shrinkage rate exceeds 3%, the dimensional stability will be poor when made into products such as non-woven fabrics.For example, when used in products such as bag filters, if kept suspended for a long time, the product will be damaged by heat. It gradually transforms.

Originally, PAS has a melting point of 280°C or higher and a glass transition temperature of 85°C or higher, which are higher than conventional general-purpose fibers, so when producing staple fibers made of PAS as described above, the spinning temperature and drawing/heat treatment temperature are high. The spinning temperature is 290 to 310℃ (spinning point +10 to 3
0°C). Outside this temperature range, nozzle clogging and thread breakage occur. In addition, the stretching temperature is ± the glass transition temperature of PAS.
20°C, preferably ±10°C, and the stretching ratio is 2.0
-4.0, preferably 2.5-3.5. Furthermore, heat treatment is performed at 160 to 180° C. for 1 to 10 seconds under tension.

By stretching and heat treating under the above conditions, the birefringence is 0.150 to 0.300 and the strength is 3.5 g/d or more.
, it is possible to obtain fibers having physical property values of elongation of 30% or more. Furthermore, heat treatment after stretching is particularly important for controlling fiber crystallization.

The crimping may be applied to the fibers after drawing and heat treatment by a conventional method. As another method, for example, as disclosed in Japanese Patent Publication No. 62-23082, a spinneret having a spinning hole capable of producing hollow fibers is used, and a thread is formed asymmetrically in the cross-sectional direction directly under the spinneret. Latent crimp may be imparted by cooling to If such latent crimp is not provided, a commonly used spinneret having circular spinning holes or irregularly shaped spinning holes may be used.

The crimped PA S la fibers obtained as described above are cut into a predetermined length according to a conventional method to obtain staple fibers.

Incidentally, the birefringence in the present invention is the birefringence per turn and the per-turn reduction.

The dry heat shrinkage rates were determined as follows.

Birefringence: Using a polarizing microscope (manufactured by Kon, POH type), a Berek convensator (manufactured by Leitz), a spectral light source activation device (Na light source, Toshiba 5LS-3-B type), length 5 ~ 6 mm ia f (t 45 to the fiber axis
A sample was cut at an angle of 30°, adjusted on the stage of a polarizing microscope so that the cut surface was facing up, and the analyzer was inserted to set the field of view.
Count the number of stripes (n pieces). Turn the compensator clockwise and measure the compensator scale A where the sample first becomes darkest, and turn the compensator counterclockwise and measure the compensator scale A where the sample first becomes darkest. (read up to 1/10 scale in both cases). Furthermore, the compensator is returned to 30, the analyzer is removed, the diameter d of the sample is measured, and the birefringence (Δn) is calculated based on the following formula (average value of 20 measurements).

Δn”T/d (T=nλ.+6) λo= 589.3 mμ [However, ε: C/ of the Leitz compensator manual
i determined from 10000 and i: (a-b) (difference in compensator reading)] Number of crimp = number of crimp per 25 mm when the initial load of 2 mg/d is applied to IL fiber (pcs/25 mm) Curling ratio: The length when an initial load of 2 mg/d is applied to a single fiber is a, 5
Let b be the length when a load of mg/d is applied.

Dry heat shrinkage rate: 160 according to JISL1015-1981
Measured in °C.

[Examples and Comparative Examples] (Example) Intrinsic viscosity 0.220 (20 in 1-chloronaphthalene
After melt-spinning PPS (measured at 6°C) at 300°C, it was bundled into a tow, wet-stretched to 2.8 times at 95°C, and
Tension heat treatment was carried out at ℃. 150 tons of drawn tow (1 million denier) of the obtained pps fiber (4L yarn 2 denier)
It was crimped according to a conventional method at a pressing pressure of 1 kg/cm', and further cut into staples of a predetermined length (50 mm) according to a conventional method. The obtained staple fibers were drawn in a conventional manner through a cart process and then made into a nonwoven fabric by needle punching. Table 1 shows the birefringence, 1 turn, 9 turns, and dry heat shrinkage.

Furthermore, the obtained non-woven fabric was sewn into a bag filter for 180 yen.
A practical test was conducted for several days as a coal dust removal filter. The results are shown in Table 1.

(Comparative example) A stretched tow obtained in the same manner as in the example was crimped at a temperature of 13
Staple fibers and nonwoven fabrics were obtained by changing the temperature to 0°C, and practical tests were conducted in the same manner. The results are also listed in Table 1.

1st front card passability is the staple 11Xl of the example! While the fibers were good, in the comparative examples with poor crimp characteristics, curling occurred and it was very difficult to obtain a web. On the other hand, in terms of long-term durability as a filter, examples with low dry heat shrinkage can withstand high temperatures and exhibit extremely good durability, while comparative examples have birefringence that satisfies the range of the present invention but with dry heat shrinkage. Since the ratio was out of the range of the present invention, the mechanical properties and dimensional stability were poor and sagging occurred, making it difficult to use as a bag filter.

[Effects of the Invention] Since the present invention is configured as described above, the high crimping/low shrinkage staple fiber of the present invention has excellent strength and other properties as a fiber, as well as heat resistance and chemical resistance. Because it has excellent dimensional stability, it is useful as a material for textile products that can withstand use even under harsh conditions, such as industrial filters, papermaking canvas, electrical insulation materials, and protective clothing.

Claims (1)

[Claims] (1) Made of polyarylene sulfide, birefringence: 0.150 to 0.300, number of crimp: 10 or more/25mm, crimp ratio: 10% or more, dry heat (160°C) shrinkage: 3% or less A staple fiber with high crimping and low shrinkage.