Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Including a second component containing structurally defined...
Reexamination Certificate
1999-01-06
2002-02-12
Thibodeau, Paul (Department: 1773)
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Including a second component containing structurally defined...
C428S458000, C428S461000, C428S480000, C525S064000, C525S176000
Reexamination Certificate
active
06346320
ABSTRACT:
DETAILED DESCRIPTION OF THE INVENTION
1. Technical Field
The present invention relates to a thermoplastic resin composition having excellent durability, especially a polyester resin composite molded article having excellent thermal shock resistance.
2. Background Arts
Polybutylene terephthalate is a thermoplastic material having excellent moldability and exhibiting various excellent characteristics such as solvent resistance, and is used in various fields because a molded article having good physical and mechanical properties can be produced by the melt-molding and injection molding of the polymer.
Examples of representative applications of the resin are electrical and electronic parts, housing of household appliance and automobile. According to the recent tendency to save the energy and cost, an integral molding of a resin material together with a different material such as metal becomes more frequent rather than the use of the resin material as a singly molded part. Thermal stress is generated in the article integrally molded with a metal by the expansion and shrinkage caused by the ambient temperature change because of the non-homogeneous structure of the article.
The durability to thermal stress is called as thermal shock resistance, and a severer thermal shock resistance is required for electrical equipment to be used in an engine room of automobile. The thermal shock resistance of a resin material can be improved by a method to compound a graft polymer composed of an acrylic acid ester and a crosslinkable monomer together with an epoxy compound as disclosed in JP-A 63-3055 (hereunder, JP-A means “Japanese Unexamined Patent Publication) [JP-B 5-25260 (hereunder, JP-B means “Japanese Examined Patent Publication)], a method to compound an olefinic copolymer composed of an &agr;-olefin and an &agr;,&bgr;-unsaturated acid glycidyl ester as disclosed in JP-A 6-304963, and a method to compound a graft copolymer of an ethylene-unsaturated carboxylic acid alkyl ester copolymer and a copolymer of a vinyl polymer as disclosed in JP-A 6-304964.
Since a technique to compound a copolymer having epoxy group such as glycidyl group or to compound an epoxy compound is used in these methods, the viscosity increase takes place in a molding method necessitating a long molding cycle such as insert molding to produce a problem of failing in getting an essentially stable molded article.
JP-A 55-50058 (JP-B 57-59261) discloses a technique to improve the impact resistance by mixing a thermoplastic polyester resin under melting with a graft-modified ethylene polymer having a crystallinity of 75% or below and a melt index of 0.01 to 50 and produced by grafting an ethylene polymer or an ethylene-&agr;-olefin copolymer with an &agr;,&bgr;-unsaturated carboxylic acid or its acid derivative. Since the technique described in JP-A 55-50058 does not use glass fibers, the obtained composition has low impact resistance and thermal shock resistance insufficient for the use as the composite molded article of the present invention.
JP-A 8-253663 discloses that the thermal-shock resistance of a polyester resin is improved and a light-weight resin composition having excellent impact resistance can be produced by compounding a polyester resin with a graft-modified ethylene-propylene-nonconjugated diene copolymer produced by graft-modifying an ethylene-propylene-nonconjugated diene copolymer with a glycidyl-containing compound and a vinyl monomer.
JP-A 8-283543 discloses that the thermal-shock resistance and weld properties of a polyester resin are improved and a light-weight resin composition having rigidity and impact resistance can be produced by compounding a polyester resin with a polypropylene resin and a graft-modified olefinic elastomer produced by the graft-modification of an olefinic elastomer with a glycidyl-containing compound and a vinyl monomer.
The techniques described in the above JP-A 8-253663 and JP-A 8-283543 use the method to compound a copolymer having epoxy group such as glycidyl group and, accordingly, cause the viscosity increase in a molding method necessitating a long molding cycle such as insert molding to fail in getting an essentially stable molded article.
DISCLOSURE OF THE INVENTION
The object of the present invention is to provide a polyester resin composite molded article having excellent thermal shock resistance and retention stability in the molding cycle of insert molding, etc.
Other objects and advantages of the present invention will be clarified by the following descriptions.
As a result of vigorous investigation to solve the above problems, the inventors of the present invention found that the thermal shock resistance and melt thermal stability were remarkably improved by blending a polybutylene terephthalate with a specific modified polyolefin resin elastomer and adjusting the elastomer particles existing in the composite molded article to have a prescribed particle diameter.
The present invention has the following constitution.
1. A polyester resin composite molded article composed of a resin composition (A) comprising a polybutylene terephthalate (A1), an inorganic filler (A2) and a modified ethylenic copolymer (A3) produced by the graft-polymerization of an &agr;,&bgr;-unsaturated carboxylic acid or its acid derivative and a metal (B) wherein a part or total of the metal (B) is covered with the resin composition (A), the graft copolymer (A3) is present in the form of dispersed particles in the molded part of the resin composition constituting the composite molded article, and the diameter of the dispersed particles is between 1 and 3 &mgr;m.
2. A polyester resin composite molded article described in the above item 1 wherein the modified ethylenic copolymer (A3) is a modified ethylenic copolymer (A3) graft-polymerized with an acid derivative of an &agr;,&bgr;-unsaturated carboxylic acid.
3. A polyester resin composite molded article described in the above item 1 wherein the resin composition (A) is composed of 100 parts by weight of a polybutylene terephthalate (A1), 1 to 125 parts by weight of an inorganic filler (A2) and 5 to 20 parts by weight of a modified ethylenic copolymer (A3) graft-polymerized with an acid derivative of an &agr;, &bgr;-unsaturated carboxylic acid.
4. A polyester resin composite molded article described in the above item 1 wherein the polybutylene terephthalate (A1) has an intrinsic viscosity of from 0.5 to 0.9 dl/g.
<<Polybutylene terephthalate>>
The polybutylene terephthalate (A1) to be used in the present invention is a polyester produced by using terephthalic acid as a main acid component and 1,4-butanediol as a main glycol component. The main component means a component accounting for not less than 80 mol %, preferably not less than 90 mol % of the total acid component or total glycol component.
Examples of the copolymerizable acid component are aromatic dicarboxylic acids other than terephthalic acid such as isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenyl ether dicarboxylic acid, diphenoxyethanedicarboxylic acid and diphenyl ketone dicarboxylic acid; aliphatic dicarboxylic acids such as succinic acid, adipic acid and sebacic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid and tetralindicarboxylic acid; etc.
Examples of the copolymerizable glycol component are ethylene glycol, hexamethylene glycol, neopentyl glycol, cyclohexane dimethanol, tricyclodecane dimethylol, xylylene glycol, bisphenol A, bisphenol B and bishydroxyethoxy bisphenol A.
The polyester may be copolymerized with a polyfunctional compound such as glycerol, trimethylolpropane, pentaerythritol, trimellitic acid or pyromellitic acid in an amount not to essentially lose the molding performance of the polyester, for example not more than 3 mol %.
Examples of the other copolymerizable component usable in the production of polybutylene terephthalate are hydroxy acids such as p-hydroxybenzoic acid and p-hydroxyethoxybenzoic acid.
The polybutylene terephthalate used in the present invention has an intri
Doteguchi Mitsuru
Tadokoro Naonobu
Sughrue & Mion, PLLC
Teijin Limited
Thibodeau Paul
Zacharia Ramsey
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