JP2887381B2 - Polyphenylene sulfide monofilament - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyphenylene sulfide monofilament which maintains high strength and elongation and has particularly excellent bending wear properties, and is particularly suitable for industrial uses such as canvas for papermaking and filter fabric. .

[0002]

2. Description of the Related Art In industrial applications such as textiles for canvas for papermaking and textiles for filters, since these textiles are exposed to a high-temperature atmosphere of, for example, 130 ° C. or more, or a chemical environment such as a high concentration of acids and alkalis, Monofilaments that are woven materials have been required to have high heat resistance and chemical resistance as well as mechanical properties such as high knot strength and high tensile strength.

Conventionally, aramid fibers (trade name: NOMEX or KEVLAR) and polytetrafluoroethylene (trade name: TEFLON) are used as industrial fibers satisfying such required characteristics as required. However, the use of these polymers has been severely limited because of their inability to be melt-extruded and their high cost.

On the other hand, polyphenylene sulfide has excellent heat resistance and outstanding chemical resistance and is capable of being melt-molded. Therefore, in addition to so-called molded article applications, techniques applied to fibers and films have been conventionally used. The production of fibers has been discussed, for example, in U.S. Pat. Nos. 3,895,091, 3,898,204, 3,912,695, and 4,02.
9,639, 4,098,776,
No. 4,115,562, JP-A-49-5461.
No. 7, JP-B-52-12240, JP-B-52
-30609, JP-A-57-143518, JP-A-58-18409, and JP-A-58-31
112 and JP-A-61-75812.

Utilizing the above-mentioned excellent properties of polyphenylene sulfide monofilament, it is also possible to use the same for fabric for papermaking canvas.
No. 6390 has proposed this.

[0006] However, polyphenylene sulfide fibers have excellent heat resistance and chemical resistance, but have the disadvantage that the yarn itself is brittle and brittle, and the toughness is insufficient. doing.

Therefore, when polyphenylene sulfide monofilament is applied to a fabric for a papermaking canvas, the bending abrasion after weaving is remarkably inferior. However, there is a problem that durability in this aspect is low.

[0008]

SUMMARY OF THE INVENTION The present invention has been achieved as a result of study for solving the problems of the above-mentioned conventional polyphenylene sulfide monofilament.

Accordingly, an object of the present invention is to provide a polyphenylene sulfide monofilament which maintains strength and elongation at a high level, has excellent flex wear resistance, and is particularly suitable for industrial uses such as canvas for papermaking and filter fabric. It is in.

[0010]

In order to achieve the above-mentioned object, the polyphenylene sulfide monofilament of the present invention comprises (A) at least 85 mol% of the structural units composed of p-phenylene sulfide units, and has a melt flow rate of 200%. (B) a monomer mixture 2 of 50 to 90% by weight of an aromatic vinyl compound and 10 to 50% by weight of a vinyl cyanide compound in the presence of 50 to 80 parts by weight of low-density polyethylene based on the following polyphenylene sulfide:
It is characterized in that a composition containing 2.5 to 12.0% by weight of a graft copolymer obtained by graft copolymerizing 0 to 50 parts by weight is melt-spun.

The polyphenylene sulfide (A) used in the present invention is a polymer in which 85% by mole or more of the structural units are composed of p-phenylene sulfide units, and contains other copolymer components in a range of 15% by mole or less. Can be. In addition, when the p-phenylene sulfide unit is less than 85 mol%, heat resistance is unfavorably deteriorated.

Further, the polyphenylene sulfide to be used may contain a heat-resistant agent, a weathering agent, a light-proofing agent, an antistatic agent, a dye, a pigment and a small amount of a crosslinking component such as trichlorobenzene.

The polyphenylene sulfide used in the present invention is a polymer having a melt flow rate measured by JIS K-6900: melt flow rate (hereinafter referred to as MFR).
Is preferred to be in the range of 200 or less, particularly 160 or less, since it is excellent in melt spinning and stretchability and the obtained monofilament has high tensile strength. When the MFR of polyphenylene sulfide exceeds 200, a monofilament which sufficiently satisfies both tensile strength and knot strength may not be obtained.

On the other hand, the component (B) used in the present invention comprises:
Graft copolymerization of 20 to 50 parts by weight of a monomer mixture of 50 to 90% by weight of an aromatic vinyl compound and 10 to 50% by weight of a vinyl cyanide compound in the presence of 50 to 80 parts by weight of low density polyethylene. A graft copolymer, wherein the aromatic vinyl compound referred to herein is styrene,
α-methylstyrene and the like, and examples of the vinyl cyanide compound include acrylonitrile and methacrylonitrile. In addition, other vinyl compounds such as methyl methacrylate and methyl acrylate can be copolymerized at a small ratio.

When the proportion of the low-density polyethylene in the graft copolymer (B) is less than 50 parts by weight, the abrasion resistance of the monofilament cannot be sufficiently improved, and when it exceeds 80 parts by weight, the phase with polyphenylene sulfide cannot be obtained. It is not preferable because the solubility is lowered.

The above graft copolymer (B) can be produced under graft copolymerization conditions such as emulsion polymerization, suspension polymerization, bulk polymerization and the like. Made, Modiper 1400, 1401
And the like.

The amount of the graft copolymer (B) relative to the polyphenylene sulfide (A) is 2.5 to 1
The range of 2.0% by weight, particularly 5.0 to 8.0% by weight is suitable. If it is less than 2.5% by weight, the effect of improving the flexural wear is insufficient, and if it exceeds 12.0% by weight. Conversely, not only is the bending wear property lowered, but also the intrinsic tensile strength and tensile elongation of the polyphenylene sulfide monofilament are lowered, which is not preferable.

Means for obtaining a composition comprising (A) polyphenylene sulfide and (B) a graft copolymer include a method of mixing pellets, a method of dry blending and repelletizing, and a method of separately supplying to an extruder. Conventional means such as a method of melting and mixing can be employed.

The method of melt-spinning a composition comprising (A) polyphenylene sulfide and (B) a graft copolymer to form a monofilament is not particularly limited, but the melt extrusion temperature is usually 20 times lower than the melting point of the polymer. ~ 6
A temperature of 0 ° C., especially 30-50 ° C. higher, is preferred. The melt-spun yarn is usually cooled and solidified in warm water of 60 ° C. or higher.

The undrawn monofilament obtained is subsequently drawn at a temperature above its glass transition temperature.
In this stretching step, it is desirable to perform two or more stages of stretching and to set the total stretching ratio to 4.5 to 5.2 times. As the stretching atmosphere, a warm water bath, an air bath, a steam bath, or the like is suitably used.

The stretched polyphenylene sulfide monofilament is used for the purpose of adjusting the residual shrinkage and the like.
It is subsequently subjected to a heat treatment, this heat treatment being 140-21
It is preferable to carry out the reaction in an air bath at 0 ° C., particularly 160 to 190 ° C., in a fixed length state.

The polyphenylene sulfide monofilament of the present invention thus obtained has the excellent heat resistance and chemical resistance of polyphenylene sulfide itself, and the monofilament has a diameter of 0.10 to 0.10.
The tensile strength and the knot strength in the range of 1.0 mm are excellent in balance, exhibit sufficient toughness, and particularly excellent in flex wear.

Therefore, the polyphenylene sulfide monofilament of the present invention has a suitable performance particularly for industrial uses such as canvas for papermaking and filter fabric.

[0024]

The configuration and effects of the present invention will be further described with reference to examples.

Example 1 Polyphenylene sulfide having an MFR of 70 and a glass transition temperature of 90.5 ° C. (manufactured by Toray Phillips, E188
0), a graft copolymer obtained by graft copolymerizing a monomer mixture of styrene and acrylonitrile on low-density polyethylene (“MODIPA A1401” manufactured by NOF Corporation)
... Low density polyethylene: monomer mixture weight ratio = 50: 5
0) was melted at 320 ° C. by a 40 mm diameter extruder spinning machine and melt-extruded from a die having a hole diameter of 1.5 mm.

The spun yarn was immediately introduced into a cooling hot water bath at 80 ° C., cooled, then primary-drawn 3.7 times in a steam bath at 98 ° C., and subsequently in an air bath at 160 ° C. 1.
Secondary stretching was performed 311 times.

The stretched monofilament was subsequently wound in a 160 ° C. air bath after a 1.0-fold constant-length heat treatment.

With respect to the obtained polyphenylene sulfide monofilament, the results of evaluation of flex wear resistance, tensile strength, tensile elongation and knot strength are also shown in Table 1.

The physical properties of the monofilament were evaluated by the following methods.

The abrasion resistance of the monofilament was 0.160 g /
The test was performed under the following conditions by applying a load of d, and the number of times until the monofilament was cut was measured. Friction speed: 60 times / min Friction angle: 110 degrees Reciprocating distance: 2.5 cm Test length: 20 cm Friction element: 1.0 mmφ hard steel The number of tests was set to 10 times, and the average value was shown. The greater the number, the better the flex wear.

The tensile strength, tensile elongation and knotty elongation were all measured in accordance with JISL1013-1981.

[0032]

[Table 1] As is evident from the results in Table 1, the polyphenylene sulfide monofilaments of the present invention (Nos. 3 to 6) have high flexural wear while maintaining high tensile strength, tensile elongation and knot strength. Has improved.

Example 2 The polyphenylene sulfide used in Example 1 was
A graft copolymer (“MODIPA A1400” manufactured by NOF Corporation, low-density polyethylene: monomer mixture weight ratio = 70: 30) obtained by graft-copolymerizing a monomer mixture of styrene and acrylonitrile to low-density polyethylene was used. % By weight, and the other properties were evaluated for the polyphenylene sulfide monofilament obtained by melt spinning, two-stage drawing and constant length heat treatment under the same conditions as in Example 1, and as a result, the number of times of flexural wear: 8737 times, tensile Strength: 4.02
g / d, tensile elongation: 38.1%, knot strength: 2.74 g / d
And the nodule elongation was 24.9%, and the physical properties were well balanced.

[0034]

As described in detail above, the polyphenylene sulfide monofilament of the present invention has the excellent heat resistance and chemical resistance of polyphenylene sulfide itself, and the diameter of the monofilament is 0.1%.
Tensile strength and knot strength in the range of 0 to 1.0 mm are excellent in balance, exhibit sufficient toughness, and particularly excellent in flex wear.

Accordingly, the polyphenylene sulfide monofilament of the present invention has suitable performance particularly for industrial uses such as canvas for papermaking and filter fabric.

Claims (1)

(57) [Claims] (A) at least 85 mol% of the structural unit is p-
(B) In the presence of 50 to 80 parts by weight of low-density polyethylene, 50 to 90% by weight of an aromatic vinyl compound and a vinyl cyanide compound 10 in the presence of 50 to 80 parts by weight of low-density polyethylene, which are composed of phenylene sulfide units and have a melt flow rate of 200 or less. A polyphenylene sulfide monofilament obtained by melt-spinning a composition containing 2.5 to 12.0% by weight of a graft copolymer obtained by graft copolymerizing 20 to 50 parts by weight of a monomer mixture of 50 to 50% by weight.