JPH01215833A - Production of poly-p-phenylene sulfide molding - Google Patents

Abstract

PURPOSE:To improve the heat resistance of a molding of a polymer based on poly-p-phenylene sulfide at relatively low temperature in good efficiency without causing any dimensional change of the molding, by irradiating said molding with an ionizing radiation. CONSTITUTION:A polymer (A) mainly consisting of repeating p-phenylene sulfide units is optionally mixed with additives (B) such as another polymer (e.g., PP), an antioxidant, a slip agent, a matting agent and a pigment, and the obtained mixture is molten at 290-330 deg.C and molded into any desired shape to obtain a molding having a temperature higher than the glass transition temperature of component A. This molding is irradiated with an ionizing radiation at a dose of 5-100 Mrad in air under conditions of a temperature of 100-200 deg.C and an acceleration voltage of 10-10,000kV.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for producing heat-resistant polyP-phenylene sulfide (hereinafter abbreviated as PPS)-based molded products useful as fibers, films, and other molded products. Regarding.

(Prior art) PPS has excellent properties in terms of heat resistance, weather resistance, chemical resistance, flame retardancy, etc., and can be melt-molded. It has attracted attention in the field of molded products, and market development is progressing.

The reason why pps has high heat resistance is that it has a relatively high melting point (
Of course, the temperature is 280 to 290°C), which makes it possible to use it in a high temperature range compared to polyester (polyethylene terephthalate) and the like.

However, its heat resistance is also high temperature filter.

In the fields of FPCs, capacitors, etc., it is said that this is still insufficient, and the reality is that there is a desire to put into practical use products that can withstand use at higher temperatures.

As a countermeasure against this, it has been proposed to take advantage of the phenomenon in which heat treatment of pps in the presence of oxygen causes a curing reaction (molecular chain extension, crosslinking, etc.), which apparently improves heat resistance. C.D., G.

Brady; J, 8pp1. Polymer, sci.
, 20.2541 (1976)).

(Problem to be Solved by the Invention) However, in this method, in which a melt-molded molded product is heated and cured at a temperature of 200"C or higher and below the melting point of PPS, the heat of PPS is There was a problem in that the dimensional change caused by the dimensional change was large, and if the processing temperature was lowered in an attempt to reduce the dimensional change, the expected degree of hardening would be reduced.

An object of the present invention is to provide a method that can improve the heat resistance of PPS molded products at relatively low temperatures.

(Means for Solving the Problems) The present inventors have conducted intensive research to provide a method for improving the heat resistance of PPS molded products that does not have the above-mentioned problems. Contrary to the conventional knowledge that PPS-based molded products are insensitive to radiation, the heat resistance of PPS-based molded products is significantly improved by irradiation with ionizing radiation, and the effect is achieved only at temperatures above the glass transition point of PPS-based polymers. The present invention was achieved by discovering that irradiation at 100° C. is sufficient.

That is, the present invention provides a method for producing a heat-resistant PPS molded article, which comprises irradiating ionizing radiation to a molded article that is made of a polymer whose main component is PPS and has a temperature equal to or higher than the glass transition point of the polymer. The main points are as follows.

In the present invention, a molded article made of a polymer whose main component is PPS is a polymer whose main repeating unit is a pps component, preferably 80 mol% or more, particularly preferred,
means fibers, films, and other molded products made of a polymer in which 90 mol% or more is occupied by a PPs component, but other polymers, such as polyethylene, polypropylene, polyamide, polyester, may be used within the range that does not impede the purpose of the present invention. , polyarylate, polystyrene, polycarbonate, polyphenylene oxide, polyimide, polyamideimide, polyetheretherketone, polyetherketone, polysulfone, polyethersulfone, etc., or, for example, antioxidants, slip agents,
Matting agents, pigments.

It may also contain additives such as glass fiber.

When PPS contains other copolymerization components, the copolymerization components include 9, for example, a trifunctional component and a sulfone component.

Examples include an ether component, a ketone component, a meta bond component, a biphenyl bond component, a substituted sulfide component, and the like.

These PPS or copolymerized PP mainly composed of these PPS
S can be synthesized by a conventionally known method, such as the method described in US Pat. No. 3,354,129, in which P-dichlorobenzene and sodium sulfide are reacted in a polar solvent.

The molded article included in q) of the present invention can be molded into a desired shape by a conventionally known melt molding method. The spot/
), the melting temperature of the polymer is 290-330'l
is preferable, and in the case of fibers and films, stretching is performed if necessary.

To the present invention. Therefore, in order to improve the heat resistance of PPS-based molded articles, ionizing radiation is irradiated to the molded article having a temperature equal to or higher than the glass transition point of the Fl)S-based polymer.

Examples of ionizing radiation include electron beams and gamma rays, with electron beams being preferably used.

The radiation dose is 5 to 100 Mrad, especially 1
0 to 100 Mrad is preferred. If the dose is too large, the physical properties of the molded article may deteriorate, which is not preferable. Furthermore, when using an electron beam, the depth that the electron beam reaches increases linearly in proportion to the accelerating voltage, so it is preferable to increase the accelerating voltage in accordance with the thickness of the molded product. The acceleration voltage is
10~100OOKV.

A range of 50 to 5000 KV is particularly preferred. The temperature of the molded article during irradiation is required to be higher than the glass transition point of the pps polymer. If the temperature is lower than the glass transition point, the effect of improving heat resistance will be reduced. Since the glass transition point of PPS polymer is usually 80 to 95°C, processing at a higher temperature than this temperature range is required, but the practical temperature is 100 to 200°C. The higher the temperature, the shorter the time required for irradiation, but if the temperature is too high, dimensional changes may occur in the molded product, so the temperature is preferably 200°C or less. The irradiation atmosphere is in the air.

Irradiation in an inert gas (nitrogen, argon, etc.) or vacuum is usually selected, but irradiation in air is most practical.

(Example) The present invention will be explained in more detail below using Examples.

In addition, the heat resistance evaluation was performed at 260°C or 270°C.
The degree of deformation of the film after being immersed in a solder bath for 10 seconds was determined visually.

Examples 1-4. Comparative Examples 1 to 3 PPS pellets were melt-extruded from a T-die at 300°C to obtain unstretched films. The obtained unstretched film was stretched 3.0 times in length in an atmosphere at 100°C.

A stretched film having a thickness of 10 μm was obtained by simultaneous biaxial stretching at a magnification of 3.0 times in the horizontal direction. The melting point of this film is 285°C
, the glass transition point was 85°C.

This stretched film was irradiated with electron beams using an electron beam irradiation device with an accelerating voltage of 750 KV at various temperatures and doses shown in Table 1 (the absorbed dose per sandstone was I Mra
d) The heat resistance of the obtained film was measured and the results shown in Table 1 were obtained.

From Table 1 it is clear that the temperature during irradiation is extremely important.

Table 1 Note: ◎: No deformation, ○: Almost no deformation ×: Large deformation (Effect of the invention) According to the present invention, the heat resistance of PPS molded products can be efficiently improved without causing any dimensional changes. be able to.

Patent applicant: Yu-Tei Riki Co., Ltd.

Claims (1)

[Claims] (1) A heat-resistant polyP-phenylene sulfide system consisting of a polymer whose main component is polyP-phenylene sulfide, characterized by irradiating ionizing radiation to a molded article having a temperature equal to or higher than the glass transition point of the polymer. Method of manufacturing molded products.