JPH05140409A - Thermoplastic resin composition - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a resin composition as a molded article, which is excellent in rigidity, dimensional stability and heat resistance. [Structure] 40 to 95% by weight of a polyester resin (polybutylene terephthalate is a preferred embodiment),
Acrylic polymer (I) and aromatic vinyl compound and /
Alternatively, a thermoplastic resin composition containing 60 to 5% by weight of a copolymer (II) composed of a vinyl cyanide compound.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin composition, and more particularly to a thermoplastic resin composition which is excellent in rigidity and has excellent dimensional accuracy and heat resistance of the obtained molded product.

[0002]

2. Description of the Related Art Polyester resins represented by polybutylene terephthalate (hereinafter abbreviated as PBT) or polyethylene terephthalate generally have various excellent properties such as mechanical strength, chemical resistance and heat resistance. Since it is a resin material, it can be used for electrical and electronic parts,
Widely used in automobile parts or other machine parts. However, polyester is a crystalline resin and has the drawback of large dimensional change.

Generally, as a means for improving the dimensional stability of a polyester resin, a method of blending an amorphous resin represented by ABS or AS is known. However, A
When BS is added, the dimensional stability is improved, but the heat resistance is lowered.

The inventors of the present invention have conducted extensive studies to further improve such characteristics, and as a result, achieved the present invention.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a resin composition which has excellent rigidity and dimensional stability and heat resistance when formed into a molded product.

[0006]

The present invention relates to polyester resin (A) 40
AAS resin (B) 60 of ˜95% by weight and a copolymer (II) obtained by polymerizing an acrylic polymer (I) with an aromatic vinyl compound and / or a vinyl cyanide compound
It is a thermoplastic resin composition consisting of 5 wt%.

In the present invention, the polyester resin (A) means a polyester resin comprising an acid component mainly containing terephthalic acid and a glycol component. Here, "mainly" means 80 mol% or more, preferably 90 mol% or more, based on the total acid components, and may be copolymerized with other acid components and / or glycol components as necessary. May be.

Examples of the acid component copolymerizable with the polyester resin (A) of the present invention include dicarboxylic acids other than terephthalic acid, such as isophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid and diphenyldicarboxylic acid. Acid, diphenyl ether dicarboxylic acid, diphenoxyethane dicarboxylic acid, diphenyl ketone dicarboxylic acid, diphenyl sulfone dicarboxylic acid, succinic acid,
Examples thereof include adipic acid, sebacic acid, cyclohexanedicarboxylic acid, tetralindicarboxylic acid and decalindicarboxylic acid. These dicarboxylic acid components may be esterified with a monohydric alcohol such as methanol.

The glycol component is 1,4-
Examples are Buntadiol, ethylene glycol, hexamethylene glycol, neopentyl glycol, cyclohexanedimethanol, tricyclodecanedimethylol, xylylene glycol, bisphenol A, bisphenol B, and bishydroxyethoxybisphenol A.

Of these, PBT having terephthalic acid as the dicarboxylic acid component and 1,4-butanediol as the glycol component is preferable.

Polyester resin (A) used in the present invention
Is the intrinsic viscosity (using orthochlorophenol as a solvent
(Measured at ° C) is preferably 0.4 to 1.5.

The polyester resin (A) is manufactured by a known method. That is, after the esterification or transesterification reaction, the polycondensation reaction is carried out under high vacuum. If necessary, the melt-polymerized polyester resin can be further solid-phase polymerized.

In the present invention, the polyester resin (A)
Occupies 40 to 95% by weight in the resin composition. If the polyester resin (A) is less than 40% by weight, mechanical strength and chemical resistance cannot be obtained. On the other hand, if it exceeds 95% by weight, sufficient dimensional stability cannot be obtained.

The AAS resin (B) used in the present invention comprises an acrylic polymer (I) and a copolymer (II) obtained by polymerizing an aromatic vinyl compound and / or a vinyl cyanide compound. It is a resin.

The acrylic polymer (I) constituting the AAS resin is a polymer of acrylic acid ester or a copolymer obtained by polymerizing acrylic acid ester and a small amount of a crosslinkable monomer.

Here, as the acrylic ester, butyl acrylate, methyl acrylate, ethyl acrylate, propyl acrylate, hexyl acrylate,
It is an alkyl ester of acrylic acid such as 2-ethylhexyl acrylate having 1 to 13 carbon atoms. The acrylic ester may be used alone or in combination of two or more kinds thereof and copolymerized. Of these, n-butyl acrylate is preferred.

Examples of the crosslinkable monomer include triallyl cyanurate, triallyl isocyanurate, triacrylic formal, butylene diacrylate, butylene dimethacrylate, trimethylolpropane trimethacrylate, divinylbenzene, vinyl acrylate, vinyl methacrylate, allyl acrylate, Examples thereof include polyvalent vinyl compounds and polyvalent allyl compounds such as allyl methacrylate, diallyl malate, diallyl fumarate, diallyl itaconate, monoallyl malate, monoallyl fumarate and triacyl cyanurate. Of these, triallyl isocyanurate and triallyl cyanurate are preferable.

As the aromatic vinyl compound constituting the copolymer (II) obtained by polymerizing an aromatic vinyl compound and / or a vinyl cyanide compound, styrene, α-methylstyrene, α-chlorostyrene, α- Examples include bromostyrene and vinyltoluene. Of these, styrene and / or α-methylstyrene is preferable.

Further, as the vinyl cyanide compound,
Examples thereof include acrylonitrile and methacrylonitrile, and acrylonitrile is particularly preferable.

The above-mentioned copolymer (II) is produced by emulsion polymerization, solution polymerization, bulk polymerization, suspension polymerization or the like.

In the present invention, the AAS resin (B) is 60
Occupy ~ 5% by weight. If the AAS resin (B) is less than 5% by weight, sufficient dimensional stability cannot be obtained. On the other hand, when it exceeds 60% by weight, the mechanical strength and chemical resistance of the polyester resin are deteriorated.

If desired, the resin composition of the present invention may contain other additives such as colorants, heat stabilizers, antioxidants, ultraviolet absorbers, mold release agents, crystallization nucleating agents, crystallization accelerators and fillers. A flame retardant or the like may be added. In particular, when melt heat stability at the time of molding and heat resistance of the product are required, it is desirable to add a heat stabilizer or an antioxidant.

The method for producing the resin composition of the present invention is not particularly limited and can be prepared by a known method.

For example, polyester resin (A) and AAS
A general method is to obtain a mixture of the resin (B) and other components by melt mixing.

The resin composition of the present invention can be applied to housing materials for electric and electronic products, which are required to have dimensional accuracy and heat resistance, materials for electronic parts such as connectors, and materials for electric parts of automobiles. However, the resin composition of the present invention is not limited to the above applications.

[0026]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

All "%" in the examples are based on weight. Tensile strength and tensile elongation are ASTM: D-63
8, flexural modulus is ASTM: D-790, impact strength is A
Each was measured by the method of STM: D-256.

The dimensional stability was judged by measuring the molding shrinkage. Molding shrinkage rate (%) = {[(mold size)-(mold size)] / (mold size)} × 100

The solvent resistance was judged by the change of the surface after being immersed in toluene at 23 ° C. for 7 days.

[0030]

Examples 1 to 5 and Comparative Examples 1 to 4 PBT and AAS having an intrinsic viscosity of 0.92 (in orthochlorophenol, 35 ° C., 1.2 g / dl) as polyester resin (A).
Resin (B) [Hitachi Chemical Co., Ltd .: V6700] was mixed with the composition shown in Table 1 and melt-kneaded with a 44 mm diameter twin-screw extruder to produce molding pellets. Then 110
After hot-air drying at 5 ° C for 5 hours, injection molding was performed to obtain a test piece.

[0031]

[Table 1]

[0032]

Examples 6 to 7 and Comparative Examples 5 to 6 Molding pellets having the compositions shown in Table 2 were produced in the same manner as in Example 1. After hot-air drying at 110 ° C for an hour, injection molding is performed to ASTM
A TYPE-4 tensile dumbbell was obtained. 150 ° C for these
After heat treatment for a predetermined time with the heat aging tester set to, tensile strength and tensile elongation were measured.

As the ABS resin used in Comparative Example 5, ST-30 manufactured by Mitsui Toatsu Chemicals, Inc. was used.

[0034]

[Table 2]

Claims (2)

[Claims] 1. A thermoplastic resin composition comprising 40 to 95% by weight of a polyester resin (A) and 60 to 5% by weight of an AAS resin (B). Here, the AAS resin is composed of an acrylic polymer (I) and a copolymer (II) obtained by polymerizing an aromatic vinyl compound and / or a vinyl cyanide compound. 2. The thermoplastic resin composition according to claim 1, wherein the polyester resin (A) is polybutylene terephthalate.