JPH0465517A - Polyphenylene sulfide monofilament - Google Patents

Abstract

PURPOSE:To provide the subject monofilament having specific ash content, crystallization temperature and melt flow rate, exhibiting excellent heat- resistance, chemical resistance, tensile strength, know strength, durability and flexural abrasion resistance and suitable as a woven cloth for paper- manufacturing canvas, etc. CONSTITUTION:The objective monofilament has an ash content of <= 0.15% a crystallization temperature of >= 200 deg.C, a melt flow rate of 10-200 and preferably a flexural abrasion frequency of >= 4,500 cycles.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a polyphenylene sulfide monofilament, and more specifically, it has excellent bending abrasion resistance and bending fatigue resistance, and is particularly useful for papermaking canvas fabrics and filter fabrics. The present invention relates to polyphenylene sulfide monofilaments suitable for industrial applications such as.

[Prior Art] In industrial fabrics such as papermaking canvas fabrics and filter fabrics, the fabrics are exposed to high-temperature atmospheres of 130°C or higher, and chemical environments with high concentrations of acids and alkalis. Therefore, monofilaments, which are textile materials, are required to have mechanical properties such as high knot strength and high tensile strength, as well as heat resistance and chemical resistance.

Traditionally, aramid fibers and polytetrafluoroethylene have been used as industrial fibers that meet these required characteristics, but none of these polymers can be melt-extruded. The impossibility and high cost have severely limited its range of use.

On the other hand, polyphenylene sulfide has excellent heat resistance and outstanding chemical resistance, and can be melt-molded, so in addition to its use in so-called molded products, technology to apply it to fibers and films has been considered for a long time. Regarding the production of fibers, for example, US Pat. No. 3,895,091, US Pat. No. 3,898,204, US Pat.
Specification No. 695, Specification No. 4,029,639, Specification No. 4
, 098,776 specification, 4,115,562 specification, JP-A-49-54617, JP-B-Sho 52-1
2240, JP 52-30609, JP 57-143518, JP 58-18409
No. 1, JP-A No. 58-31112 and JP-A-Sho 6
This method has been proposed in Publication No. 1-75812 and the like.

Utilizing the above-mentioned excellent properties of polyphenylene sulfide monofilaments, it has been proposed in Japanese Patent Application Laid-Open No. 61-6390 to utilize them in fabrics for papermaking canvases.

On the other hand, as a method for improving the durability of polyphenylene sulfide monofilaments, a method of blending an ionomer resin is described in JP-A-2-53913.

[Problem to be solved by the invention] The above-mentioned US Pat. No. 3,895,091, US Pat.
No. 898,204, No. 3,912.695, No. 4,029,639, No. 4,098,7
76 specification, 4.115,562 specification, JP-A-49-54617, JP-A-52-12240, JP-A-52-30609, JP-A-57-14
3518, JP 58-18409, JP 58-31112, JP 61-75812g
Polyphenylene sulfide fibers produced by conventional techniques described in publications such as Japanese Patent Application Laid-open No. 61-6390 have excellent heat resistance and chemical resistance, but are brittle due to their hard threads and lack toughness. Therefore, it has a problem of poor durability such as bending abrasion resistance and bending fatigue resistance.

When trying to apply Konotame, for example, polyphenylene sulfide monofilament, to fabrics for papermaking canvas, there is a problem that the threads are likely to break or break during weaving, and furthermore, the bending abrasion resistance after weaving is significantly poor. For example, during use as a canvas, bent parts of the fabric tend to be damaged, and durability in this respect is low.

Further, in the case of the polyphenylene sulfide monofilament obtained by the method described in JP-A-2-53913, although the monofilament has excellent bending fatigue resistance, the improvement in bending abrasion resistance is not sufficient. In industrial applications such as fabrics for papermaking canvases, the bending abrasion resistance in particular dominates the durability during use, and it cannot be said to be sufficient for use in industrial applications.

As a result of various studies conducted by the present inventors, the polyphenylene sulfide used in the conventional method has a high ash content exceeding 0.15% and a low crystallization temperature of 200°C or less, which are the causes of low flexural abrasion resistance. I understand.

For the reasons mentioned above, although polyphenylene sulfide monofilament is an extremely promising material for use in industrial applications such as textiles for papermaking canvases, there are many problems as described above for its use in these industrial textiles. There was.

An object of the present invention is to provide a polyphenylene sulfide monofilament which has even more excellent durability, especially excellent bending abrasion resistance, than the polyphenylene sulfide monofilament obtained by the prior art described above.

[Means and effects for solving the problems] The structure of the present invention is as follows: (1) The ash content is 0.15% or less and the crystallization temperature is 20%.
A polyphenylene sulfide monofilament having a temperature of 0°C or higher and a melt flow rate of 10 to 200.

(2) The polyphenylene sulfide monofilament according to claim (1), wherein the polyphenylene sulfide monofilament has been bent and abraded 4,500 times or more.

Consisting of

The polyphenylene sulfide referred to in the present invention is composed of p-phenylene sulfide units in 80 mol% or more of the constituent units, and may contain a copolymer component in a proportion of 20 mol% or less.

In addition, polyphenylene sulfide may be blended with other thermoplastic polymers as long as they do not impede the effects of the present invention, and may further include heat resistant agents, light resistant agents, weather resistant agents, antistatic agents, dyes, pigments, etc. may contain the usual additives.

The polyphenylene sulfide referred to in the present invention has a natural strength of 0.1
5% or less, and the crystallization temperature is 200°C or higher.

When the ash content of polyphenylene sulfide exceeds 0.15%, the resulting polyphenylene sulfide monofilament becomes brittle, resulting in poor bending abrasion resistance. In addition, if the crystallization temperature is less than 200°C, the crystallinity of the obtained polyphenylene sulfide monofilament will be low.
It is easily scraped by friction, and its bending abrasion resistance is also poor.

Therefore, the ash content of polyphenylene sulfide is 0.15
% or less and the crystallization temperature is 200'C or more, the bending abrasion resistance of polyphenylene sulfide monofilament becomes sufficient for use in industrial applications such as fabrics for papermaking canvas.

In addition, the polyphenylene sulfide referred to in the present invention is an ASTM
Polymer melt flow measured by D1238-82 method: Melt flow rate (hereinafter referred to as MFR) is 10~
200, preferably from 10 to 150.

When the MFR is greater than 200, the durability of the monofilament, especially the bending abrasion resistance, is insufficient for use in industrial applications such as papermaking canvas fabrics and filter fabrics. Furthermore, when the MFR is less than 10, it becomes difficult to perform melt spinning.

Note that if polyphenylene sulfide is branched or crosslinked, problems such as poor spinning and drawing properties and low knot strength of the obtained monofilament will occur, so the polyphenylene sulfide used in the present invention is substantially It is preferably a linear high polymer.

It is preferable that the polyphenylene sulfide monofilament of the present invention be bent and abraded 4,500 times or more.

The method for measuring the number of bending abrasions will be described later, and when this value satisfies the above range, the durability of the polyphenylene sulfide monofilament is sufficient for use in industrial applications such as fabrics for papermaking canvas.

Next, one embodiment of the manufacturing method for obtaining the polyphenylene sulfide monofilament of the present invention will be described, but the present invention is not limited thereto.

Polyphenylene sulfide with an ash content of 0.15% or less, a crystallization temperature of 200°C or higher, and a melt flow rate of 10 to 200 is melted and extruded from a spinneret at a temperature 10 to 60°C higher than the melting point of polyphenylene sulfide. Monofilament and eggplant.

Next, the monofilament extruded from the above-mentioned spinneret is cooled and solidified in a cooling bath, and then taken out to form an undrawn polyphenylene sulfide monofilament.

The undrawn monofilament described above is usually subsequently continuously hot drawn at a temperature above its glass transition temperature.

In hot stretching, it is desirable to carry out multi-stage stretching of two or more stages and set the total stretching ratio to 3.5 times or more, particularly 4 times or more, in order to obtain a monofilament with excellent mechanical properties and durability.

There are no particular limitations on the means for heating the monofilament during hot stretching, but heated liquid, heated gas, steam, and the like are preferably used.

In order to improve the dimensional stability of the hot-stretched polyphenylene sulfide monofilament, it is preferable to subsequently perform heat treatment, and this heat treatment is preferably carried out in a gas bath at 160 to 250 °C in a constant length or relaxed state. .

Next, the present invention will be explained based on examples. The methods for measuring the crystallization temperature of polyphenylene sulfide, the number of bending wears, the number of bending fatigues, tensile strength and elongation, knot strength and elongation, and ash content of polyphenylene sulfide are as follows. be.

(A) Crystallization temperature DSC measurements were carried out under the following conditions, and the crystallization peak temperature upon cooling was defined as the crystallization temperature.

(DSC measurement conditions) Sample amount near mg Temperature increase rate: 20℃/min (up to 340'C) Temperature decrease knee 20℃/m1n (B,) Number of bending wear JIS L1095 7.10.2 Yarn used in B method 0.198g on monofilament by abrasion tester
A load of /d was applied and a test was further conducted under the following conditions, and the number of times it took for the monofilament to break was measured.

Friction speed = 60 times/min Friction angle: 110 degrees Round trip distance: 2.5cm Trial length: 20cm Friction element: 1. Ommφ hard steel The number of tests was 5 times, and the average value is shown.

The larger the number of times, the better the bending abrasion resistance.

(C) Bending fatigue frequency A load of 0.325 g/d was applied to the monofilament using a bending fatigue tester (manufactured by TOYO8EIKI), and the test was further conducted under the following conditions to measure the number of times the monofilament was broken.

Trial length: 8cm Swing angle: 220 degrees Rotation speed: 180 times/min The number of tests was 5 times, and the average value is shown.

The larger the number of times, the better the bending fatigue resistance.

(D) Strength and elongation Tensile strength and elongation and knot strength and elongation are both J l5L1
It was measured according to the regulations of 013-1981.

(E) Put 5 g of ash polymer into a platinum crucible and completely burn the polymer in an electric furnace. The weight of the residue in the crucible is measured, and the percentage relative to the original weight (5 g) is determined as the ash content.

[Example] Example I Polyphenylene sulfide with MFRloo, ash content of 0.03%, and crystallization temperature of 230°C was supplied to an extruder-type extruder, extruded at 320°C through a nozzle with a hole diameter of 1.5 mm, and a polyphenylene sulfide was placed directly below the nozzle. It was rapidly cooled in a hot water bath at 80°C to obtain an undrawn polyphenylene sulfide monofilament.

Subsequently, the above-mentioned undrawn polyphenylene sulfide monofilament was continuously stretched 3.5 times in a steam bath at 100°C, and further stretched 1.35 times in air at 160°C. , and was subjected to a relaxation heat treatment of 0.97 times in air at 180°C and wound up.

The obtained stretched polyurenylene sulfide monofilament had a diameter of 0.4 mm, and its mechanical properties and durability were as follows.

Tensile strength: 4.2 g/d Tensile elongation: 29% Knot strength: 3.2 g/d Nodule elongation: 25% Number of bending wear: 7060 Number of bending fatigue: 270 Example 2 MFR170, ash 0.03%, crystal Spinning and drawing were carried out in the same manner as in Example 1, except that polyphenylene sulfide having a temperature of 235°C was used.

The obtained stretched polyurenylene sulfide monofilament had a diameter of 0.4 mm, and its mechanical properties and durability were as follows.

Tensile strength: 3.9 g/d Tensile elongation: 27% Knot strength: 3.0 g/d Knot elongation: 21% Number of bending wear: 4800 Number of bending fatigue: 230 Comparative example I MFR70, ash 0.3%, crystal Polyphenylene sulfide (manufactured by Toshi Philips Vetrolium (1R: E1880)) with a temperature of 175°C was supplied to an extruder-type extruder, and extruded at 320°C through a nozzle with a hole diameter of 1.e″mm, which was placed directly below the nozzle. It was rapidly cooled in a hot water bath at 80°C to obtain an undrawn polyphenylene sulfide monofilament.

Subsequently, the above-mentioned unstretched polyphenylene sulfide monofilament was continuously stretched 4.0 times in a steam bath at 100 ° C., and further stretched 1.3 times in air at 160 ° C., and then It was subjected to a relaxation heat treatment of 0.97 times in air at 180°C and wound up.

The obtained stretched polyrenylene sulfide monofilament had a diameter of 0.41, and the mechanical properties and durability were as follows.

Tensile strength: 4.4g/d Tensile elongation: 24% Knot strength: 3. Og/d Knot elongation 14% Number of bending wear: 3700 Number of bending fatigue: 88 Because the ash content and crystallization temperature of polyphenylene sulfide were outside the range of the present invention, the number of bending wear was less than 4500.

[Effects of the present invention] The polyphenylene sulfide monofilament according to the present invention not only has the excellent heat resistance and chemical resistance of polyphenylene sulfide itself, but also has high tensile strength and knot strength, and has excellent durability, especially bending abrasion resistance. Due to its excellent properties, it is suitable for industrial applications such as fabrics for papermaking canvas.

Claims (2)

[Claims] (1) Ash content is 0.15% or less and crystallization temperature is 20%
A polyphenylene sulfide monofilament having a temperature of 0°C or higher and a melt flow rate of 10 to 200. (2) The polyphenylene sulfide monofilament according to claim (1), wherein the polyphenylene sulfide monofilament has been bent and abraded 4,500 times or more.