JP2005171184A - Method for producing polyarylene sulfide resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyarylene sulfide resin composition that has an excellent friction coefficient and an excellent wear characteristic. <P>SOLUTION: At first, (a) 100 pts.wt. of a polyarylene sulfide resin are melt-kneaded with (b) 0.1 to 5 pts.wt. of an alkoxysilane to prepare (A) a polyarylene sulfide resin composition. Then, (A) 100 pts.wt. of the resultant polyarylene sulfide resin composition are melt-kneaded with (B) 5 to 100 pts.wt. of polytetrafluoroethylene that is treated with fire, then pulverized into particles with an average particle size of 1 to 1,000 μm and (C) 10 to 200 pts.wt. of a filler. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing a polyarylene sulfide resin composition having a remarkably small friction coefficient and excellent slidability and excellent mechanical properties.

  Polyarylene sulfide (hereinafter abbreviated as PAS) resin, represented by polyphenylene sulfide (hereinafter abbreviated as PPS) resin, is excellent in heat resistance, mechanical properties, chemical resistance, dimensional stability, flame retardancy, etc. Widely used in electrical / electronic equipment parts materials, automotive equipment parts materials, chemical equipment parts materials, etc.

  However, the PAS resin has a drawback that it has a large friction coefficient in a part that slides with other parts, and a large amount of wear occurs during sliding. For this reason, although the PAS resin has the above-described excellent characteristics, there are cases where the applied parts are limited.

  As a conventional method for solving this problem, it is known to blend a fluororesin. For example, a resin composition containing a polytetrafluoroethylene resin (Patent Document 1) or a specific polytetrafluoroethylene resin (Patent Document 2) is shown. Mobility has not been obtained. In addition, blending of a fluororesin and a specific inorganic filler has been proposed (Patent Document 3), but sufficient slidability has not been improved.

On the other hand, as another method for improving the slidability, it is also known to add a carbon-based filler such as carbon fiber or amorphous carbon (Patent Document 4), but a filler having a relatively high Mohs hardness is used. In addition, the friction coefficient is not sufficiently improved and the amount of wear is large. In addition, although a resin composition to which a specific polytetrafluoroethylene resin and an inorganic filler having a low Mohs hardness are added has been proposed (Patent Document 5), sufficient wear characteristics are not obtained by a general manufacturing method. .
JP-A-63-213561 Japanese Unexamined Patent Publication No. 7-304925 JP-A-6-109146 JP-A-2-190677 JP 2002-332406 A

  An object of the present invention is to provide a PAS resin composition that improves the above-mentioned drawbacks of the prior art and is excellent in friction coefficient and wear characteristics.

  As a result of various studies from the viewpoint of composition and production in order to achieve the above-mentioned object, the present inventors have previously melt-kneaded the PAS resin and the alkoxysilane compound, and then, the specific polytetrafluoroethylene resin and the inorganic filler 10 By adding ~ 200 parts by weight and melt-kneading, it was found that a polyarylene sulfide resin composition having a remarkably small friction coefficient and excellent slidability and excellent mechanical properties was obtained, and the present invention was completed. It was.

  That is, the present invention relates to (A) (a) 100 parts by weight of a polyarylene sulfide resin and (b) 100 parts by weight of a mixture obtained by melt-kneading 0.1 to 5 parts by weight of an alkoxysilane compound. After the treatment, 5 to 100 parts by weight of a powdered polytetrafluoroethylene resin having an average particle diameter of 1 to 1000 μm and (C) 10 to 200 parts by weight of an inorganic filler are added and melt-kneaded. It is a manufacturing method of an arylene sulfide resin composition.

  ADVANTAGE OF THE INVENTION According to this invention, the problem of a sliding characteristic and a tensile characteristic can be improved dramatically and the polyarylene sulfide resin composition excellent also in various physical properties, such as another mechanical physical property, can be provided.

  Hereinafter, the present invention will be described in detail. The PAS resin as the component (A) (a) in the present invention is one in which the main repeating unit is composed of — (— Ar—S —) — (wherein Ar is an arylene group). Examples of the arylene group (—Ar—) include a p-phenylene group, an m-phenylene group, an o-phenylene group, a substituted phenylene group (wherein the substituent is an alkyl group, preferably a C1-C5 alkyl group, or a phenyl group) ), P, p′-diphenylenesulfone group, p, p′-biphenylene group, p, p′-diphenylene ether group, p, p′-diphenylenecarbonyl group, naphthalene group and the like can be used. In this case, among the arylene sulfide groups composed of the above-mentioned arylene groups, a polymer using the same repeating unit, that is, a homopolymer can be used, and in terms of processability of the composition, different repeating units are used. In some cases, copolymers containing are preferred.

  As the homopolymer, those having a p-phenylene sulfide group as a repeating unit and using a p-phenylene group as an arylene group are particularly preferably used. In addition, as the copolymer, among the arylene sulfide groups comprising the above-mentioned arylene groups, two or more different combinations can be used. Among them, combinations mainly containing p-phenylene sulfide groups and containing m-phenylene sulfide groups are available. Particularly preferably used. Among these, those containing 70 mol% or more, more preferably 80 mol% or more of p-phenylene sulfide groups are suitable from the viewpoint of physical properties such as heat resistance, moldability and mechanical properties. Further, among these PAS resins, a high molecular weight polymer having a substantially linear structure obtained by condensation polymerization from a monomer mainly composed of a bifunctional halogen aromatic compound can be particularly preferably used. In addition to the PAS resin having a structure, a polymer in which a partially branched or crosslinked structure is formed by using a small amount of a monomer such as a polyhaloaromatic compound having three or more halogen substituents during condensation polymerization can be used. It is also possible to use a polymer in which a low molecular weight linear structure polymer is heated at a high temperature in the presence of oxygen or an oxidizing agent to increase the melt viscosity by oxidative crosslinking or thermal crosslinking, thereby improving the molding processability.

The PAS resin as the component (a) is mainly composed of the linear PAS (310 ° C., viscosity at a shear rate of 1200 sec ⁻¹ of 10 to 300 Pa · s), and a part thereof (1 to 30% by weight, preferably 2 to 25% by weight), but a mixed system with a branched or cross-linked PAS resin having a relatively high viscosity (300 to 3000 Pa · s, preferably 500 to 2000 Pa · s) is also suitable. In addition, the PAS resin used in the present invention is preferably one that has been purified by removing acid by-product, etc. by performing acid washing, hot water washing, organic solvent washing (or a combination thereof) after polymerization.

  Next, the alkoxysilane compound used as the component (A) (b) in the present invention includes various types such as vinylalkoxysilane, methacryloxyalkoxysilane, epoxyalkoxysilane, aminoalkoxysilane, mercaptoalkoxysilane, etc. Can be used, but aminoalkoxysilane compounds and epoxyalkoxysilane compounds are preferred. As a compounding quantity of an alkoxysilane compound, it is 0.1-5 weight part with respect to 100 weight part of (a) polyarylene sulfide resin. If the amount is less than 0.1 parts by weight, a sufficient slidability improving effect cannot be obtained.

  In the production method of the present invention, a PAS resin (a) and an alkoxysilane compound (b) are previously melt-kneaded to prepare a mixture (A), which contains a specific polytetrafluoroethylene resin (B) and an inorganic The filler (C) is added and melt-kneaded.

  When the PAS resin (a), the alkoxysilane compound (b), the polytetrafluoroethylene resin (B), and the inorganic filler (C) are melted and kneaded together, the alkoxysilane compound (b) is converted into the polytetrafluoroethylene resin (B ) And the inorganic filler (C), resulting in insufficient dispersion of the polytetrafluoroethylene resin (B) in the PAS resin (a), resulting in satisfactory slidability and physical properties. I can't. For this reason, it is important to first melt and knead the PAS resin (a) and the alkoxysilane compound (b) to deactivate the reaction activity of the alkoxysilane compound (b).

  In actual kneading, the PAS resin (a) and the alkoxysilane compound (b) are introduced from the main feeder, melted and kneaded sufficiently, and the reaction activity of the alkoxysilane compound (b) is deactivated. A one-stage extrusion method in which the ethylene resin (B) and the inorganic filler (C) are charged from the side feeder can also be used.

  Next, the polytetrafluoroethylene resin used as the component (B) in the present invention is a polytetrafluoroethylene resin having an average particle diameter of 1 to 1000 μm, which has been pulverized and then powdered. The polytetrafluoroethylene resin that has not been subjected to the baking treatment has poor thermal stability, and sufficient slidability cannot be obtained due to decomposition or the like. The firing temperature is not particularly limited, but is preferably 360 ° C. or higher.

  The polytetrafluoroethylene resin preferably has a number average molecular weight of 100,000 or more, more preferably 200,000 or more.

  Examples of such a polytetrafluoroethylene resin include trade name KT400M available from Kitamura Co., Ltd. In addition, as a method for pulverizing the polytetrafluoroethylene resin, there are mechanical pulverization, pulverization by radiation, and the like. From the viewpoint of gas generation, mechanical pulverization is preferable.

  The amount of the component (B) is 5 to 100 parts by weight, preferably 20 to 60 parts by weight, based on 100 parts by weight of the (A) polyarylene sulfide resin. If the blending amount is less than 5 parts by weight, a sufficient sliding improvement effect cannot be obtained, and if it exceeds 100 parts by weight, it is not preferable because the amount of wear only increases.

  In the resin composition of the present invention, in order to improve the performance such as mechanical strength, heat resistance, dimensional stability (deformation resistance, warpage), electrical properties, etc. within a range that does not impair the wearability during sliding. Commonly used known inorganic fillers are blended. Depending on the purpose, fibrous (glass fiber, carbon fiber, etc.), granular (carbon black, silica, etc.), plate-like (mica etc.) fillers are used, and these may be used alone or in combination of two or more. However, those having a Mohs hardness of 3.5 or less are preferably used from the viewpoint of wear during sliding. Examples of the inorganic filler having a Mohs hardness of 3.5 or less include talc, mica, kaolin, diatomaceous earth, calcium sulfate, barium sulfate, aluminum hydroxide, magnesium hydroxide, and calcium carbonate.

  In using these fillers, it is desirable to use a sizing agent or a surface treatment agent if necessary. Examples of this are functional compounds such as epoxy compounds, isocyanate compounds, silane compounds, and titanate compounds. These compounds may be used after being subjected to surface treatment or convergence treatment in advance, or may be added at the same time as material preparation.

  The amount of the inorganic filler used is 10 to 200 parts by weight, preferably 10 to 100 parts by weight, per 100 parts by weight of (A) polyarylene sulfide resin. If the amount is less than 10 parts by weight, the desired effect cannot be obtained, and if it exceeds 200 parts by weight, the amount of wear increases, which is not preferable.

  Depending on the purpose, the resin composition of the present invention can be supplemented with a small amount of other thermoplastic resins in addition to the above components. As the other thermoplastic resin used here, any thermoplastic resin may be used as long as it is stable at a high temperature. For example, an aromatic dicarboxylic acid such as polyethylene terephthalate or polybutylene terephthalate and an aromatic composed of a diol or oxycarboxylic acid. Examples thereof include polyester, polyamide, polycarbonate, ABS, polyphenylene oxide, polyalkyl acrylate, polysulfone, polyether sulfone, polyether imide, polyether ketone, and fluororesin. These thermoplastic resins can also be used as a mixture of two or more.

Furthermore, the resin composition of the present invention includes known substances that are generally added to thermoplastic resins depending on the purpose, that is, stabilizers such as antioxidants and weathering stabilizers, colorants such as flame retardants and dyes / pigments. Further, a lubricant, a crystallization accelerator, a crystal nucleating agent, and the like can be appropriately added according to the required performance.
The resin composition of the present invention can be prepared by facilities and methods generally used for preparing a synthetic resin composition. In general, necessary components can be mixed, melt-kneaded using a single-screw or twin-screw extruder, and extruded to form pellets for molding.

  The material pellets thus obtained can be molded using generally known thermoplastic resin molding methods such as injection molding, extrusion molding, vacuum molding, compression molding, etc. The most preferable is the injection molding method. is there.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto. The specific substances (a), (b), (B) and (C) used in Examples and Comparative Examples are as follows.
(a) polyphenylene sulfide (PPS) resin;
Fortron KPS, manufactured by Kureha Chemical Industry Co., Ltd.
(b) an alkoxysilane compound;
Shin-Etsu Chemical Co., Ltd., KBE-903P (γ-aminopropyltriethoxysilane)
(B) polytetrafluoroethylene resin;
KT-400M manufactured by Kitamura Co., Ltd. (polytetrafluoroethylene resin subjected to baking treatment (baking temperature 380 ° C.), average particle size 35 μm)
(C) inorganic filler;
(C-1); CALSHITEC Brillant-1500 made by Toyo Fine Chemical (calcium carbonate (Mohs hardness 3))
(C-2); NYAD G-40 (Wollastonite (Mohs hardness 4.5)) manufactured by NYCO
In addition, the measuring method of each physical property evaluated by the Example and the comparative example is as follows.
<Evaluation of tensile properties>
The tensile strength and tensile elongation were measured according to ISO 527.
<Evaluation of sliding characteristics>
Using a Suzuki type (thrust type) friction wear tester, the slidability was evaluated with the contact area of 2 cm ² at the sliding part, with the upper side as the evaluation material and the lower side as the mating material (steel S55C). The test conditions were as follows.
・ Test speed 5mm / min ・ Load 216 N
-Test time 30 minutes The average value of the test time 30 minutes was measured as the dynamic friction coefficient. The wear state was evaluated by visually observing the wear state after the test. The case where there was almost no change in the wear surface and almost no wear powder was indicated as ◯, the case where there was a slight change in the wear surface and there was wear powder, and the case where there was a significant change in the wear surface and there was a lot of wear powder.
Example 1
First, 100 parts by weight of (a) and 0.5 part by weight of (b) were put into a twin screw extruder having a cylinder temperature of 320 ° C. and melt-kneaded, and then a pelletized mixture (A) was prepared. 40 parts by weight of (B) and 60 parts by weight of (C-1) were added to 100 parts by weight of the mixture (A), and the mixture was charged into a twin screw extruder having a cylinder temperature of 320 ° C., and melt kneaded to prepare pellets. Next, various test pieces were molded from the pellets with an injection molding machine at a cylinder temperature of 320 ° C. and a mold temperature of 150 ° C., and evaluated.
Example 2
Various test pieces were molded and evaluated in the same manner as in Example 1 except that (C-2) was used instead of (C-1).
Comparative Example 1
(a) 100 parts by weight, (b) 0.5 parts by weight, (B) 40 parts by weight and (C-1) 60 parts by weight are charged into a twin screw extruder with a cylinder temperature of 320 ° C. Was prepared. Next, various test pieces were molded from this pellet in the same manner as in Example 1 and evaluated.
Comparative Example 2
In advance, 100 parts by weight of (a), 0.5 part by weight of (b) and 40 parts by weight of (B) were put into a twin screw extruder having a cylinder temperature of 320 ° C. and melt kneaded, and then a pelletized mixture was prepared. To 140.5 parts by weight of this mixture, 60 parts by weight of (C-1) was added and charged into a twin screw extruder having a cylinder temperature of 320 ° C., and melt kneaded to prepare pellets. Next, various test pieces were molded from this pellet in the same manner as in Example 1 and evaluated.
Comparative Example 3
In advance, 100 parts by weight of (a), 0.5 part by weight of (b) and 60 parts by weight of (C-1) were put into a twin screw extruder having a cylinder temperature of 320 ° C. and melt-kneaded, and then a pelletized mixture was prepared. 40 parts by weight of (B) was added to 160.5 parts by weight of this mixture, and the mixture was charged into a twin screw extruder having a cylinder temperature of 320 ° C., and melt kneaded to prepare pellets. Next, various test pieces were molded from this pellet in the same manner as in Example 1 and evaluated.

  These results are shown in Table 1.

Claims (4)

(A) (a) 100 parts by weight of polyarylene sulfide resin (100) 100 parts by weight of a mixture obtained by melting and kneading 0.1 to 5 parts by weight of an alkoxysilane compound A polyarylene sulfide resin composition characterized by adding 5 to 100 parts by weight of a powdered polytetrafluoroethylene resin having an average particle diameter of 1 to 1000 μm and (C) 10 to 200 parts by weight of an inorganic filler, followed by melt-kneading Manufacturing method. (b) The method for producing a polyarylene sulfide resin composition according to claim 1, wherein the alkoxysilane compound is an aminoalkoxysilane compound and / or an epoxyalkoxysilane compound. (B) The method for producing a polyarylene sulfide resin composition according to claim 1 or 2, wherein the polytetrafluoroethylene resin is powdered by mechanical pulverization. (C) The method for producing a polyarylene sulfide resin composition according to any one of claims 1 to 3, wherein the inorganic filler has a Mohs hardness of 3.5 or less.