JP2001123063A - Straight-chain polyphenylene sulfide resin composition and sliding member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a straight-chain polyphenylene sulfide resin composition improved in releasability from a mold in molding. SOLUTION: The straight-chain polyphenylene sulfide resin composition comprises 48.6-58.8 wt.% of a straight-chain polyphenylene sulfide resin, 19.2-29.6 wt.% of a fluororesin, 7.7-30.0 wt.% of an oxygenzoyl polyester, and 1.5-3.9 wt.% of an oligomer having perfluoroalkyl groups and alkyl groups.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyphenylene sulfide resin composition which can be used for sliding parts such as sliding bearings and cams, and in particular, has excellent heat resistance, chemical resistance, friction and wear characteristics, and remarkable separation. The present invention relates to a linear polyphenylene sulfide resin composition which provides a moldability improving effect and a good appearance.

[0002] The present invention also relates to a sliding member composed of the linear polyphenylene sulfide resin composition.

[0003]

2. Description of the Related Art Conventionally, a linear polyphenylene sulfide resin (hereinafter abbreviated as a linear PPS resin) composition has excellent heat resistance, mechanical properties, chemical resistance, water resistance, electrical properties, and branching properties. In particular, it has superior weld tensile strength, tensile elongation, and impact resistance compared to the polyphenylene sulfide resin composition, and is being used in electrical and electronic equipment, transportation equipment, sliding parts, etc. Are expected to expand into fields that require

[0004] A method for producing such a linear PPS resin is as follows.
For example, it is disclosed in JP-A-61-7332. This method uses a high-molecular-weight linear P
For producing a PS resin, the resulting linear PPS
The resin has a high melt viscosity and is linear. Therefore, it is possible to obtain not only general molded products but also tough heat-resistant fibers, films, and the like, and it can be processed into various molded products by injection molding, extrusion molding, or the like. It is also stated that various inorganic or organic substances such as powders such as carbon black, calcium carbonate, silica and titanium oxide, and fibers such as carbon, glass, asbestos and polyaramid can be used as the filler.

The applicant of the present invention focused on the characteristics of the above-mentioned linear PPS resin, and continued research and development of resin products using the same.
As a result, a plastic retainer for bearings capable of withstanding long-term high-speed, high-load rotation under severe environmental conditions of contacting oil and chemicals at high temperatures has been provided (Japanese Patent Application Laid-Open No. 64-64).
No. 79419).

[0006]

However, the above-mentioned conventional linear PPS resin composition is inferior in moldability and, in particular, in mold releasability from a mold, hindering continuous molding and further demolding. It has been found that a defect such as poor appearance or deformation of the product is caused by poor properties. Therefore, the present invention
Linear PPS with improved releasability from mold during molding
An object of the present invention is to provide a resin composition to solve the above-mentioned conventional problems.

Another object of the present invention is to provide a sliding member having good releasability from a mold during molding and good appearance.

[0008]

The invention according to claim 1 of the present invention relates to a linear polyphenylene sulfide resin composition.
6 to 58.8% by weight and a fluororesin 19.2 to 29.6
% By weight and oxybenzoyl polyester 7.7-3
0.0% by weight, and 1.5 to 3.9% by weight of an oligomer having a perfluoroalkyl group and an alkyl group.

Further, the invention according to claim 2 relates to a sliding member, characterized in that it is composed of the linear polyphenylene sulfide resin composition according to claim 1. A fluorine-containing low polymer having a perfluoroalkyl group and an alkyl group (hereinafter also referred to as a fluorine-containing oligomer) functions as a type of surfactant, and facilitates release from a mold by its lubricating action. That is, when the linear PPS resin to which the fluorinated oligomer is added is molded in a mold, the fluorinated oligomer is oriented with the alkyl group, which is a lipophilic group, toward the resin and the perfluoroalkyl group toward the surface. .

Therefore, in the molten state of the resin, the fluorine-containing oligomer selectively floats on the contact surface between the resin and the mold. Then, the perfluoroalkyl group has a very low interfacial energy, so that the affinity with the mold decreases.
As a result, it acts as a release agent for improving release properties, and enables continuous molding of the linear PPS resin composition. The details will be described below.

The present inventors have conducted intensive studies to solve the above-mentioned problems, and the addition of a specific amount of a fluorinated oligomer to a linear PPS resin composition is effective for improving the releasability. I found that. That is, when the linear PPS resin composition contained 1.5 to 3.9% by weight of the fluorine-containing oligomer, it was revealed that the releasability of the product from the mold at the time of injection molding could be remarkably improved. .

The fluorine-containing oligomer used in the present invention is, for example, a perfluoroacrylate oligomer and another copolymerized monomer, or an oligomer having a perfluoroalkyl group and an alkyl group such as perfluoroalkylsilane. May be used alone or in combination. Such a fluorine-containing oligomer can be obtained from Asahi Glass Co., Ltd. as "Surflon (registered trademark)".

When the content of the fluorine-containing oligomer is 1.5
When the amount is less than% by weight, the effect of improving the releasability is weak. On the other hand, the content of the fluorinated oligomer was 3.9% by weight.
If it exceeds 300, the releasability improving effect is saturated. The linear PPS resin used in the present invention is a PPS resin in which a molecular chain is linearly grown to a high molecular weight in a polymerization stage.
No. 7,332, and JP-A-61-66720. Since no crosslinking agent or branching agent is added at the time of polymerization, and it has not been subjected to heat treatment at a high temperature after polymerization, it is a high polymer that does not contain a crosslinked or branched structure in the molecule, and a measure of its molecular weight Melt viscosity at 310 ° C. and a shear rate of 200
(Second) When measured at ^-1 , it is 1000 poise or more. Such a linear PPS resin can be obtained from Kureha Chemical Industry Co., Ltd. as "Photron (registered trademark) KPS".

The fluororesin used in the present invention includes:
Polytetrafluoroethylene (hereinafter referred to as PTFE),
Examples thereof include tetrafluoroethylene-hexafluoropropylene copolymer, polytrichlorofluoroethylene, and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, and PTFE is particularly preferred. Among PTFE, lubricant-grade PTFE powder having an average particle size of less than 20 μm is preferable, and Teflon (registered trademark) TLP-10, TLP-10F-1 manufactured by DuPont, and Lubron (registered trademark) manufactured by Daikin Industries, Ltd. L-2, L-5,
LD-1, Fluon (registered trademark) L16 manufactured by ICI
9, L170, L171 and the like are preferable.

Typical amounts of the linear PPS resin composition of the present invention are 48.6 to 58.8% by weight of the linear PPS resin and 7.7 to 30.5% of the oxybenzoyl polyester.
The combination is such that 0% by weight, 19.2 to 29.6% by weight of a fluororesin, and 1.5 to 3.9% by weight of a fluorinated oligomer, and the total of these four components is 100% by weight.

If the amount of the fluororesin exceeds 29.6% by weight, melt-kneading becomes difficult, and a uniformly dispersed composition cannot be obtained. The means for blending the raw material resin component, various fillers, and the fluorine-containing oligomer used in the production of the linear PPS resin composition of the present invention is not particularly limited. Other resin components such as linear PPS resin and fluorine resin, various fillers, and fluorine-containing oligomers can be individually melt-kneaded, and these materials can be previously mixed with a mixer such as a Henschel mixer or a ribbon blender. After preliminarily mixing the mixture, the mixture can be supplied to a melt mixer.

As the melt mixer, any device such as a single-screw or twin-screw extruder, a mixing roll, a pressure kneader, a Brabender plastograph and the like can be used. Alternatively, the fluorinated oligomer or its solution can be added later to the granulated composition and mixed with a Henschel mixer, V blender or the like. In the linear PPS resin composition of the present invention, an appropriate amount of various stabilizers, fluidity improvers, inorganic and organic fibrous reinforcing agents, if necessary, as long as the object of the present invention is not impaired, Various resins and the like may be appropriately added.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to examples. Note that the present invention is not limited to these examples. (Example 1) 48.6 to 60.0% by weight of linear PPS resin, 19.2 to 20.0% of oxybenzoyl polyester
A cylindrical test piece is formed using a composition consisting of 1 wt%, 19.2 wt% to 30.0 wt% of a fluororesin, and 0 wt% to 3.9 wt% of a fluorinated oligomer. The degree was evaluated.

As the linear PPS resin of each composition, "FORTRON (registered trademark) W-2" manufactured by Kureha Chemical Industry Co., Ltd. is used.
14 "as oxybenzoyl polyester as" Econol (registered trademark) E-10 "manufactured by Sumitomo Chemical Co., Ltd.
1 (S type) "as the fluororesin," Teflon (registered trademark) TLP-10 "manufactured by Mitsui Dupont Fluorochemicals Co., Ltd., which is PTFE resin powder, and Asahi Glass Co., Ltd. as the fluorine-containing oligomer. "Surflon (registered trademark) SC-101, solid content concentration 30%" was used.

The above-mentioned raw materials were prepared by using a Henschel M manufactured by Mitsui Miike Works.
ixer FM-10B was mixed to the composition shown in Table 1, the solvent contained in Surflon was volatilized, and the mixture was extruded and kneaded with a twin screw extruder (MODEL PCM-30) manufactured by Ikegai Iron Works Co., Ltd. After that, a cylindrical test piece having an outer diameter of 16 mm, an inner diameter of 12 mm and a length of 10 mm was formed by injection molding with a side gate using an injection molding machine (MODEL SIM-4749) manufactured by Techno Plus Co., Ltd.

As an evaluation, each test piece was visually observed and its appearance was observed by a stereoscopic microscope, and the dimensional accuracy was evaluated by measuring the roundness of the inner diameter at the center of the cylindrical test piece. The results are shown in Table 1. The results of the external appearance observation are represented by x for unacceptable, を for acceptable, and Δ for middle. In addition, the evaluation results of the dimensional accuracy indicate that circularity of 15 μm or less is ○, 15 to 30 μm
Are represented by Δ, and those exceeding 30 μm are represented by ×.

[0022]

[Table 1]

[0023]

As described above, according to the first aspect of the present invention,
Since the linear polyphenylene sulfide resin composition according to the present invention includes an oligomer having a perfluoroalkyl group and an alkyl group, excellent releasability that can not be considered in a conventional linear polyphenylene sulfide resin composition Is obtained. Further, the sliding member according to claim 2 of the present invention has good releasability from a metal mold and appearance during molding.

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Claims (2)

[Claims] 1. A linear polyphenylene sulfide resin (48.6 to 58.8% by weight) and a fluororesin (19.2 to 2).
9.6% by weight and oxybenzoyl polyester 7.7
A linear polyphenylene sulfide resin composition comprising: 30.0% by weight and 1.5 to 3.9% by weight of an oligomer having a perfluoroalkyl group and an alkyl group. 2. A sliding member comprising the linear polyphenylene sulfide resin composition according to claim 1.