Stock material or miscellaneous articles – Composite – Of metal
Reexamination Certificate
2000-03-22
2001-01-30
Acquah, Samuel A. (Department: 1711)
Stock material or miscellaneous articles
Composite
Of metal
C525S063000, C525S064000, C525S065000, C525S068000, C525S069000, C525S070000, C525S071000, C525S074000, C525S078000, C525S165000, C525S174000, C525S185000, C525S240000, C525S242000, C525S437000, C525S445000, C524S444000, C524S469000, C524S492000, C524S502000, C524S504000, C524S513000, C428S480000
Reexamination Certificate
active
06180251
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a polyester resin composition having excellent flame-retardance and heat shock property, and it also relates to an insert molded article having excellent flame-retardance and heat shock property, obtained by an insert-molding of the polyester resin composition with a metal or an inorganic solid.
BACKGROUND OF THE INVENTION
The insert molding method is a molding method in which a metal or inorganic solid (hereinafter, abbreviated as metals) is embedded in a resin for utilizing the property of the resin and the material property of the metals. It is applied in wide fields such as automobile parts and electric and electronic parts, and presently one of general molding methods. However, since expansion and shrinkage coefficient (so-called liner expansion coefficient) are extremely different between a resin and metals, molded articles having thin resin portions, portions with large variation in thickness or sharp corners composed of metals, suffer from a lot of troubles such as cracking just after molding and cracking by temperature change in use. Particularly in the case of electric and electronic parts, since high flame-retardance is also required, thermosetting resins such as phenol resins and epoxy resins are widely used for an insert molding.
However, thermosetting resins have disadvantages such as lower productivity due to a long molding cycle and low recycling property, so that substitution with thermoplastic resins is required eagerly.
SUMMARY OF THE INVENTION
The present inventors have intensively studied, in view of the above-described problems, to obtain a thermoplastic resin for insert molding, having excellent flame-retardance, not cracking by temperature change and having excellent heat shock property, and which can be suitably used for electric and electronic parts in particular. As a result, it has been found that a composition, mainly comprising a thermoplastic polyester resin and containing an impact resistance giving agent, inorganic filler, flame-retardant and aromatic ester compound compounded therein, is excellent in flame-retardance and heat shock property, and that an insert molded article prepared by using this composition has sufficient flame-retardance as electric and electronic parts and simultaneously sufficient heat shock resistance causing no crack by common temperature change, whereby completing the present invention.
That is, an object of the present invention is
a flame-retardant polyester resin composition, obtained by blending a thermoplastic polyester resin (A) with
1 to 25% by weight, based on the total amount of the composition, of an impact resistance giving agent (B),
1 to 50% by weight, based on the total amount of the composition, of an inorganic filler (C),
1 to 25% by weight, based on the total amount of the composition, of a flame-retardant (D) and
0.1 to 10% by weight, based on the total amount of the composition, of an aromatic polyvalent carboxylate (E),
and an insert molded article obtained by an insert-molding of the flame-retardant polyester resin composition with a metal or an inorganic solid.
In other words, the composition comprises (A), 1-25% by weight of (B), 1-50% by weight of (C), 1-25% by weight of (D) and 0.1-10% by weight of (E), which are all based on the total amount of the composition. The amount of (A) may be 20-96.9% to 100% by weight of the composition.
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below. First, the thermoplastic polyester resin (A), which is a base resin in the present invention, is a polyester obtained by, for example, polycondensation of a dicarboxylic acid compound with a dihydroxy compound, polycondensation of an oxycarboxylic acid compound, and polycondensation of ternary compounds thereof, and may be any of homopolyesters and copolyesters. Examples of the dicarboxylic acid compound constituting the thermoplastic polyester resin (A) herein used include known dicarboxylic acids such as terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenylethane dicarboxylic acid, cyclohexane dicarboxylic acid, adipic acid and sebacic acid, and alkyl-, alkoxy- or halogen-substituted compounds thereof. These dicarboxylic acid compounds can also be used for polymerization in the form of ester-formable derivatives, for example, lower alcohol esters such as a dimethyl ester.
Then, examples of the dihydroxy compound constituting the thermoplastic polyester resin (A) of the present invention include hydroxy compounds such as ethylene glycol, propylene glycol, butane diol, neopentyl glycol, hydroquinone, resorcin, dihydroxyphenyl, naphthalene diol, dihydroxyphenyl ether, cyclohexane diol, 2,2-bis(4-hydroxyphenyl)propane and diethoxylated bisphenol A, polyoxyalkylene glycol and alkyl-, alkoxy- or halogen-substituted compounds thereof, and one or more of them can be added. Examples of the oxycarboxylic acid compound include oxycarboxylic acids such as oxybenzoic acid, oxynaphthoic acid and diphenyleneoxycarboxylic acid, and alkyl-, alkoxy- or halogen-substituted compounds thereof. Further, ester-formable derivatives of these compounds can also be used. In the present invention, one or more of these compounds are used. In addition to the above-described compounds, polyesters having a branched or cross-linked structure obtained by using a small amount of a trifunctional monomer, such as, trimellitic acid, trimesic acid, pyromellitic acid, pentaerythritol and trimethylolpropane, may be used.
In the present invention, any of thermoplastic polyesters produced by polycondensation using the above-described compounds as monomer components, can be used as the component (A) of the present invention, and they are used alone or in combination of two or more. Preferably, is used a polyalkylene terephthalate, further preferably a polybutylene terephthalate and copolymers including such terephthalate as the main component. In the present invention, thermoplastic polyesters may be modified according to a known method such as cross-linking and graft polymerization.
Representative examples of the impact resistance giving agent (B) used in the present invention, thermoplastic elastomers and core-shell polymers are cited. These thermoplastic elastomers are a generic name of the polymer substances which can be melt-mixed with thermoplastic polyester resins because they are solids having rubber-like elasticity at normal temperature, but heating them decreases the viscosity thereof.
The kind of the thermoplastic elastomer is not particularly restricted, and olefin-, styrene-, polyester-, polyamide- and urethane-based elastomers are listed, for example.
Preferable as the olefin-based elastomer are copolymers mainly comprising ethylene and/or propylene, and specific examples thereof include, but are not limited to, an ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-octene copolymer, ethylene-propylene-butene copolymer, ethylene-propylene-diene copolymer, ethylene-ethyl acrylate copolymer, ethylene-vinyl acetate copolymer and ethylene-glycidyl methacrylate copolymer. Among the olefin-based elastomers, preferably used are graft copolymers obtained by chemically bonding, either in branched or cross-linked structure, (a-1) an ethylene-unsaturated alkyl carboxylate copolymer or (a-2) an olefin-based copolymer composed of an &agr;-olefin and a glycidyl ester of an &agr;, &bgr;-unsaturated acid with one or more of (b) a polymer or copolymer mainly comprising a repeating unit represented by the following general formula (1):
(wherein, R represents hydrogen or a lower alkyl group, X represents one or more groups selected from —COOH, —COOCH
3
, —COOC
2
H
5
, —COOC
4
H
9
, —COOCH
2
CH(C
2
H
5
)C
4
H
9
,
and —CN.)
Such graft copolymer particularly has an effect for improving heat shock property, and is particularly suitable as the impact resistance giving agent. Specific examples of the ethylene-unsaturated alkyl carboxylate copolymer (a-1) inclu
Aoki Kei
Kanai Hiroyuki
Katsumata Toru
Acquah Samuel A.
Nixon & Vanderhye P.C.
Polyplastics Co. Ltd.
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