JP7357507B2 - Thermoplastic resin composition and molded body - Google Patents

Description

The present invention relates to a thermoplastic resin composition and a molded article, and more specifically, a thermoplastic resin composition that has an extremely low warpage property, excellent hydrolysis resistance, excellent heat resistance, and excellent mechanical strength. The present invention relates to a molded article made of the same.

Polybutylene terephthalate resin has excellent mechanical strength, chemical resistance, electrical insulation, etc., and is therefore widely used in electrical and electronic equipment parts, interior and exterior parts for automobiles, other electrical parts, mechanical parts, and the like.

However, since polybutylene terephthalate resin is a crystalline resin, it has a high molding shrinkage rate, and especially when it is compounded with reinforcing fillers such as glass fibers, it tends to have a large anisotropy, causing the molded product to warp. There are cases. Therefore, methods of mixing various amorphous resins have been proposed in order to reduce warpage.

Patent Document 1 describes (a) a polyester resin of 50 to 96% by weight, (b) a rubber-modified polystyrene resin of 35 to 3% by weight, and (c) an aromatic polycarbonate resin and/or a styrene-maleic anhydride copolymer of 15 to 15% by weight. A polyester resin composition in which resin (A) consisting of 1% by weight is blended with (B) glass fibers to which a sizing agent containing an amino-based silane coupling agent and a novolac type epoxy resin is attached, and (C) an epoxy compound is fluidized. The invention is described as having excellent properties, dimensional accuracy, and heat resistance. However, such polyester resin compositions are required to be further improved in terms of heat resistance and low warpage.

Patent Document 2 describes (A) thermoplastic polyester resin 10 to 80% by weight, (B) epoxy group-containing vinyl copolymer 1 to 15% by weight, (C) ABS resin 1 to 15% by weight, (D) (d-1) Maleic anhydride-modified polystyrene resin, (d-2) rubber-modified polystyrene resin, and (d-3) 2 or more resins from 1 to 20% by weight of polycarbonate resin, (E) 0 to 50% glass fiber % by weight, (F) 3 to 20% by weight of a halogenated epoxy brominated flame retardant, and (G) an antimony compound of 1 to 10% by weight. It is described that, in addition to low warpage, it has excellent heat cycleability, dimensional stability after annealing treatment, and heat-resistant rigidity. However, extremely high levels of heat resistance and low warpage are required these days, and the thermoplastic polyester resin composition described in Patent Document 2 is still insufficient in terms of heat resistance and low warpage.

Furthermore, since polybutylene terephthalate resin has low hygroscopicity, it is essentially not affected by water at room temperature. However, at high temperatures, the ester group is hydrolyzed by water or steam to generate hydroxyl and carboxyl groups, and the carboxyl group acts as an autocatalyst to further promote hydrolysis, which limits its use in humid heat environments. For this reason, it is also required to have high stability against hydrolysis, and to have excellent hydrolysis resistance so that it can be used even in a moist heat environment.

Japanese Patent Application Publication No. 2006-16559 Japanese Patent Application Publication No. 2007-314619

An object (problem) of the present invention is to provide a thermoplastic resin composition that has an extremely low warpage property, excellent hydrolysis resistance, excellent heat resistance, and excellent mechanical strength, and a molded article made from the same. There is a particular thing.

As a result of intensive studies to solve the above-mentioned problems, the present inventors blended a small amount of low-viscosity polybutylene terephthalate resin with high-viscosity polystyrene resin or rubber-reinforced polystyrene resin (HIPS), and further achieved a specific weight A resin composition containing an epoxy group-containing compound with an average molecular weight has a uniquely extremely low warpage property and excellent hydrolysis resistance, and also has excellent heat resistance and mechanical strength. It was discovered that a resin composition can be obtained, and the present invention was achieved.
The present invention relates to the following thermoplastic resin composition and molded article.

[1] (A) 10 to 50 parts by mass of polybutylene terephthalate resin having an intrinsic ^viscosity (IV) of 0.3 to 0.8 dl/g, (B) melt viscosity (η 50 to 90 parts by mass of a polystyrene resin or rubber-reinforced polystyrene resin having a weight average molecular weight of 80 to 500 Pa·sec, and (C) an epoxy group-containing compound having a weight average molecular weight of 200 to 10,000, to the above (A) and (B). ), based on a total of 100 parts by mass, a thermoplastic resin composition containing 0.1 to 5 parts by mass.
[2] The thermoplastic resin composition according to the above [1], wherein the weight average molecular weight and epoxy equivalent of the epoxy group-containing compound (C) satisfy the following formula.
1.5<[weight average molecular weight of (C)/epoxy equivalent of (C)]<50
[3] The thermoplastic resin according to [1] or [2] above, further containing (D) a compatibilizing agent from 1 to 25 parts by mass based on 100 parts by mass in total of (A) and (B). Composition.
[4] The thermoplastic resin composition according to any one of [1] to [3] above, wherein the terminal carboxyl group concentration of the polybutylene terephthalate resin (A) is 0.1 to 30 eq/ton.
[5] The heat according to any one of [1] to [4] above, further comprising (E) 10 to 150 parts by mass of glass fiber based on 100 parts by mass of the total of (A) and (B). Plastic resin composition.
[6] A molded article comprising the thermoplastic resin composition according to any one of [1] to [5] above.
[7] The molded body according to the above [6], wherein the molded body is a casing for an equipment component mounted on an automobile.

The thermoplastic resin composition of the present invention selectively uses a polystyrene resin or a rubber-reinforced polystyrene resin having a melt viscosity (η) in the range of 80 to 500 Pa·sec to a low molecular weight polybutylene terephthalate resin, and has a weight average molecular weight By containing an epoxy group-containing compound with 200 to 10,000, the polybutylene terephthalate resin phase tends to become a matrix phase (a sea with a sea-island structure), and the polystyrene resin or rubber-reinforced polystyrene resin phase tends to exist in the form of islands. As a result, it has extremely low warpage, excellent hydrolysis resistance, excellent heat resistance, and excellent mechanical strength.
Therefore, the thermoplastic resin composition of the present invention can be suitably used for parts of various electrical and electronic devices, interior or exterior parts for automobiles, and the like.

The thermoplastic resin composition of the present invention comprises (A) 10 to 50 parts by mass of a polybutylene terephthalate resin having an intrinsic viscosity (IV) of 0.3 to 0.8 dl/g, (B) 250°C, 912 sec ^-1 50 to 90 parts by mass of a polystyrene resin or rubber-reinforced polystyrene resin having a melt viscosity (η) of 80 to 500 Pa·sec, and (C) an epoxy group-containing compound having a weight average molecular weight of 200 to 10,000 It is characterized in that it is contained in an amount of 0.1 to 5 parts by weight based on a total of 100 parts by weight of (A) and (B).

Embodiments of the present invention will be described in detail below. Although the following description may be made based on embodiments and specific examples, the present invention is not interpreted as being limited to such embodiments and specific examples.
In addition, in this specification, "~" is used to include the numerical values described before and after it as a lower limit value and an upper limit value.

[(A) Polybutylene terephthalate resin]
The thermoplastic resin composition of the present invention contains (A) polybutylene terephthalate resin having an intrinsic viscosity (IV) of 0.3 to 0.8 dl/g.
By using a material with an intrinsic viscosity (IV) in the range of 0.3 to 0.8 dl/g, the characteristics of polybutylene terephthalate resin are strongly manifested, and it has excellent heat resistance and low warpage, as well as mechanical strength and The resin composition also has excellent chemical resistance.
If a polybutylene terephthalate having an intrinsic viscosity (IV) lower than 0.3 dl/g is used, the heat resistance of polybutylene terephthalate will not be exhibited and the mechanical strength will tend to be low. In addition, if it is higher than 0.8 dl/g, it becomes difficult to form the above-mentioned sea-island structure, and (B) polystyrene resin or rubber-reinforced polystyrene resin tends to form a sea, resulting in poor fluidity of the resin composition and poor moldability. Easy to do. The intrinsic viscosity (IV) is preferably 0.4 dl/g or more, more preferably 0.5 dl/g or more, further preferably 0.55 dl/g or more, and preferably 0.75 dl/g or less.

In the present invention, the intrinsic viscosity of the polybutylene terephthalate resin (A) is a value measured at 30° C. in a mixed solvent of tetrachloroethane and phenol at a ratio of 1:1 (mass ratio).

(A) Polybutylene terephthalate resin is a polyester resin having a structure in which terephthalic acid units and 1,4-butanediol units are ester-bonded, and in addition to polybutylene terephthalate resin (homopolymer), terephthalic acid units and 1,4-butanediol units are , 4-butanediol units, and a mixture of a homopolymer and the copolymer.

(A) The polybutylene terephthalate resin may contain dicarboxylic acid units other than terephthalic acid, and specific examples of other dicarboxylic acids include isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,5-naphthalene dicarboxylic acid, and -Naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, biphenyl-2,2'-dicarboxylic acid, biphenyl-3,3'-dicarboxylic acid, biphenyl-4,4'-dicarboxylic acid, bis(4,4'- Aromatic dicarboxylic acids such as (carboxyphenyl)methane, anthracene dicarboxylic acid, and 4,4'-diphenyl ether dicarboxylic acid; alicyclic dicarboxylic acids such as 1,4-cyclohexane dicarboxylic acid and 4,4'-dicyclohexyl dicarboxylic acid; and aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, and dimer acid.

The diol unit may contain other diol units in addition to 1,4-butanediol, and specific examples of other diol units include aliphatic or alicyclic diols having 2 to 20 carbon atoms. , bisphenol derivatives, and the like. Specific examples include ethylene glycol, propylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, decamethylene glycol, cyclohexanedimethanol, 4,4'-dicyclohexylhydroxymethane, 4,4 '-dicyclohexylhydroxypropane, ethylene oxide-added diol of bisphenol A, and the like. In addition to the bifunctional monomers mentioned above, trifunctional monomers such as trimellitic acid, trimesic acid, pyromellitic acid, pentaerythritol, and trimethylolpropane can be used to introduce branched structures, and fatty acids and the like can be used to adjust the molecular weight. Small amounts of monofunctional compounds can also be used in combination.

As described above, the polybutylene terephthalate resin (A) is preferably a polybutylene terephthalate homopolymer obtained by polycondensing terephthalic acid and 1,4-butanediol. It may be a polybutylene terephthalate copolymer containing one or more dicarboxylic acids and/or one or more diols other than 1,4-butanediol as the diol unit, and (A) the polybutylene terephthalate resin is In the case of polybutylene terephthalate resin modified by polymerization, specific preferred copolymers include polyester ether resin copolymerized with polyalkylene glycols, particularly polytetramethylene glycol, and dimer acid copolymerized polybutylene terephthalate. resin, isophthalic acid copolymerized polybutylene terephthalate resin.
Note that these copolymers have a copolymerization amount of 1 mol % or more and less than 50 mol % of the total segment of the polybutylene terephthalate resin. Among these, the amount of copolymerization is preferably 2 mol% or more and less than 50 mol%, more preferably 3 to 40 mol%, particularly preferably 5 to 20 mol%. Such a copolymerization ratio tends to improve fluidity and toughness, which is preferable.

(A) The polybutylene terephthalate resin preferably has a terminal carboxyl group content (hereinafter sometimes referred to as AV) of 0.1 to 30 eq/ton. If it exceeds 30 eq/ton, hydrolysis resistance and alkali resistance tend to deteriorate, and gas tends to be generated during melt molding of the resin composition. The amount of terminal carboxyl groups is more preferably 3 eq/ton or more, further preferably 5 eq/ton or more, more preferably 25 eq/ton or less, still more preferably 20 eq/ton or less.

In addition, the amount of terminal carboxyl groups of polybutylene terephthalate resin is a value measured by dissolving 0.5 g of polyalkylene terephthalate resin in 25 mL of benzyl alcohol and titrating using a 0.01 mol/l benzyl alcohol solution of sodium hydroxide. be. The amount of terminal carboxyl groups can be adjusted by any conventionally known method, such as adjusting polymerization conditions such as raw material charging ratio, polymerization temperature, and pressure reduction method during polymerization, or reacting with a terminal blocking agent. That's fine.

(A) Polybutylene terephthalate resin is produced by melt polymerizing a dicarboxylic acid component whose main component is terephthalic acid or an ester derivative thereof and a diol component whose main component is 1,4-butanediol in a batch or continuous manner. It can be manufactured using Further, after producing a low molecular weight polybutylene terectate resin by melt polymerization, the degree of polymerization (or molecular weight) can be increased to a desired value by further performing solid phase polymerization under a nitrogen stream or under reduced pressure.
(A) Polybutylene terephthalate resin is obtained by a manufacturing method in which a dicarboxylic acid component whose main component is terephthalic acid and a diol component whose main component is 1,4-butanediol are continuously melt-polycondensed. is preferred.

The catalyst used in carrying out the esterification reaction may be any conventionally known catalyst, and examples thereof include titanium compounds, tin compounds, magnesium compounds, calcium compounds, and the like. Particularly preferred among these are titanium compounds. Specific examples of the titanium compound as an esterification catalyst include titanium alcoholates such as tetramethyl titanate, tetraisopropyl titanate, and tetrabutyl titanate, and titanium phenolates such as tetraphenyl titanate.

[(B) Polystyrene resin or rubber reinforced polystyrene resin]
The thermoplastic resin composition of the present invention contains (B) a polystyrene resin and/or a rubber-reinforced polystyrene resin.
The polystyrene resin may be a styrene homopolymer or a copolymer of other aromatic vinyl monomers such as α-methylstyrene, paramethylstyrene, vinyltoluene, vinylxylene, etc. in an amount of 50% by mass or less. There may be.

The rubber-reinforced polystyrene resin is preferably one copolymerized or blended with a butadiene rubber component, and the amount of the butadiene rubber component is usually 1% by mass or more and less than 50% by mass, preferably 3 to 40% by mass. , more preferably 5 to 30% by weight, still more preferably 5 to 20% by weight.
High impact polystyrene (HIPS) is particularly preferred as the rubber reinforced polystyrene resin.

In the present invention, (B) polystyrene resin or rubber-reinforced polystyrene resin having a melt viscosity (η) of 80 to 500 Pa·sec at 250° C. and 912 sec ⁻¹ is used. Polystyrene resin or rubber-reinforced polystyrene resin having such a melt viscosity (η) is mixed with (A) 10 to 50 parts by mass of polybutylene terephthalate resin, (B) based on a total of 100 parts by mass of (A) and (B). By blending polystyrene resin or rubber-reinforced polystyrene resin in an amount of 50 to 90 parts by mass, (A) polybutylene terephthalate resin becomes dominant in terms of physical properties, resulting in extremely low warpage and high heat resistance. can be achieved. When the melt viscosity (η) is less than 80 Pa·sec, heat resistance becomes insufficient.

The melt viscosity (η) is preferably 90 Pa·sec or more, more preferably 100 Pa·sec or more, even more preferably 110 Pa·sec or more, especially preferably 120 Pa·sec or more, particularly preferably 130 Pa·sec or more. Moreover, the upper limit thereof is preferably 400 Pa·sec or less, more preferably 300 Pa·sec or less, further preferably 200 Pa·sec or less, and especially preferably 180 Pa·sec or less, particularly preferably 160 Pa·sec or less.
Note that the melt viscosity can be measured according to ISO 11443 using a capillary rheometer and a slit die rheometer.

As mentioned above, the content of (A) polybutylene terephthalate resin is 10 to 50 parts by mass based on the total of 100 parts by mass of (A) and (B), and the content of (B) polystyrene resin or rubber reinforced polystyrene resin is 50 to 50 parts by mass. 90 parts by mass, but preferably (A) is 10 parts by mass or more and less than 50 parts by mass, more preferably 20 parts by mass or more and less than 50 parts by mass, even more preferably 22 parts by mass or more and less than 50 parts by mass, and even more preferably 25 parts by mass. The amount is at least 50 parts by weight, particularly preferably from 25 to 48 parts by weight. (B) is preferably more than 50 parts by mass and not more than 90 parts by mass, more preferably more than 50 parts by mass and not more than 80 parts by mass, even more preferably more than 50 parts by mass and not more than 78 parts by mass, especially more than 50 parts by mass and not more than 75 parts by mass, Particularly preferably, it is 52 parts by mass or more and 75 parts by mass or less.

[(C) Epoxy group-containing compound]
The thermoplastic resin composition of the present invention contains (C) an epoxy group-containing compound. (C) The epoxy group-containing compound is used to suppress the polybutylene terephthalate resin from undergoing hydrolysis and causing a decrease in molecular weight as well as a decrease in mechanical strength, etc. In the present invention, (C) the epoxy group-containing compound As the group-containing compound, one having a weight average molecular weight (Mw) of 200 to 10,000 is used. When the Mw exceeds 10,000, the (A) polybutylene terephthalate resin increases in viscosity, the (A) polybutylene terephthalate resin phase becomes difficult to become a matrix phase, and the heat resistance of the resin composition decreases. Mw is preferably 9000 or less, more preferably 8000 or less, especially 7000 or less, especially 6000 or less, particularly preferably 5000 or less, preferably 250 or more, still more preferably 500 or more, particularly preferably 1000 or less. That's all.

(C) The epoxy group-containing compound may be any compound having one or more epoxy groups in one molecule, and is usually glycidyl, which is a reaction product of alcohol, phenol, or carboxylic acid, etc., and epichlorohydrin. A compound or a compound in which an olefinic double bond is epoxidized may be used.
(C) Epoxy group-containing compounds include, for example, novolak epoxy compounds, bisphenol A epoxy compounds, bisphenol F epoxy compounds, alicyclic epoxy compounds, glycidyl ethers, glycidyl esters, epoxidized butadiene polymers, and resorcinol. Examples include type epoxy compounds.

Examples of the novolak-type epoxy compound include phenol novolac-type epoxy compounds, cresol novolac-type epoxy compounds, and the like.
Examples of bisphenol A-type epoxy compounds include bisphenol A-diglycidyl ether and hydrogenated bisphenol A-diglycidyl ether, and examples of bisphenol F-type epoxy compounds include bisphenol F-diglycidyl ether and hydrogenated bisphenol F-diglycidyl ether. Examples include ether.

Examples of alicyclic epoxy compounds include vinylcyclohexene dioxide, dicyclopentadiene oxide, 3,4-epoxycyclohexyl-3,4-cyclohexylcarboxylate, bis(3,4-epoxycyclohexylmethyl)adipate, vinylcyclohexene dioxide, Examples include epoxide, 3,4-epoxycyclohexyl glycidyl ether, and the like.

Specific examples of glycidyl ethers include monoglycidyl ethers such as methyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, decyl glycidyl ether, stearyl glycidyl ether, phenyl glycidyl ether, butylphenyl glycidyl ether, and allyl glycidyl ether; Examples include diglycidyl ethers such as pentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, glycerin diglycidyl ether, propylene glycol diglycidyl ether, and bisphenol A diglycidyl ether.

Examples of the glycidyl esters include monoglycidyl esters such as benzoic acid glycidyl ester and sorbic acid glycidyl ester; diglycidyl esters such as adipic acid diglycidyl ester, terephthalic acid diglycidyl ester, and orthophthalic acid diglycidyl ester.

Examples of the epoxidized butadiene polymer include epoxidized polybutadiene, epoxidized styrene-butadiene copolymer, and epoxidized hydrogenated styrene-butadiene copolymer.
Examples of resorcin type epoxy compounds include resorcin diglycidyl ether.

(C) The epoxy group-containing compound may be a copolymer containing a glycidyl group-containing compound as one component. Examples include copolymers of glycidyl esters of α,β-unsaturated acids and one or more monomers selected from the group consisting of α-olefins, acrylic acid, acrylic esters, methacrylic acid, and methacrylic esters. It will be done.

The epoxy group-containing compound (C) is preferably one in which the relationship between weight average molecular weight and epoxy equivalent satisfies the following formula (1).
1.5<[weight average molecular weight of (C)/epoxy equivalent of (C)]<50 (1)
When the ratio (Mw/eq) of weight average molecular weight of (C)/epoxy equivalent of (C) becomes 50 or more, the polybutylene terephthalate resin increases in viscosity due to the reaction with the epoxy group-containing compound, resulting in a decrease in heat resistance. If it becomes 1.5 or less, the effect of improving hydrolysis resistance tends to be insufficient. Mw/eq is more preferably 1.7 or more, still more preferably 3.0 or more, more preferably 40 or less, still more preferably 30 or less.

The epoxy equivalent of the epoxy group-containing compound (C) is preferably 150 to 1000 g/eq. If the epoxy equivalent is less than 150 g/eq, the amount of epoxy groups will be too large, resulting in a high viscosity of the resin composition, and if the epoxy equivalent is more than 1000 g/eq, the amount of epoxy groups will be small. The effect of improving the alkali resistance and hydrolysis resistance of the polybutylene terephthalate resin composition tends to be difficult to sufficiently exhibit. The epoxy equivalent is more preferably 160 to 800 g/eq, still more preferably 170 to 700 g/eq, and most preferably 180 to 650 g/eq.

(C) As the epoxy group-containing compound, bisphenol A type epoxy compounds and novolak type epoxy compounds obtained from the reaction of bisphenol A or novolac with epichlorohydrin tend to improve hydrolysis resistance and alkali resistance. This is particularly preferred from the viewpoint of the surface appearance of the molded product.

(C) The content of the epoxy group-containing compound is 0.1 to 5 parts by mass, based on a total of 100 parts by mass of (A) polybutylene terephthalate resin and (B) polystyrene resin or rubber-reinforced polystyrene resin, and 0. It is preferably 15 parts by mass or more, more preferably 0.2 parts by mass or more, further preferably 0.25 parts by mass or more, preferably 4 parts by mass or less, more preferably 3 parts by mass or less, and even more preferably 2.5 parts by mass. Parts or less, particularly preferably 2 parts by mass or less. (C) If the content of the epoxy group-containing compound is less than 0.1 part by mass, a decrease in hydrolysis resistance and alkali resistance tends to occur, and if it is more than 5 parts by mass, crosslinking will progress and flow during molding. Sexual behavior tends to deteriorate.

[(D) Compatibilizer]
It is preferable that the resin composition of the present invention further contains (D) a compatibilizer. (D) By containing a compatibilizer, the compatibilization of (A) polybutylene terephthalate resin and (B) polystyrene resin or rubber-reinforced polystyrene resin is promoted, thereby dispersing in the (A) polybutylene terephthalate resin phase. (B) The dispersed particle size of the polystyrene resin or rubber-reinforced polystyrene resin becomes smaller and the interfacial strength increases, making it easier to obtain excellent mechanical strength and excellent appearance.

(D) The compatibilizing agent is not particularly limited as long as it can fulfill the function of compatibilizing the (A) polybutylene terephthalate resin and (B) polystyrene resin or rubber-reinforced polystyrene resin. Compound-based compatibilizers are preferred.

(D) As the compatibilizer, polycarbonate resin or styrene-maleic acid copolymer is particularly preferred.

Polycarbonate resins are optionally branched thermoplastic polymers or copolymers obtained by reacting dihydroxy compounds or small amounts of polyhydroxy compounds with phosgene or carbonic acid diesters.

The dihydroxy compound as a raw material is substantially free of bromine atoms, and is preferably an aromatic dihydroxy compound. Specifically, 2,2-bis(4-hydroxyphenyl)propane (i.e., bisphenol A), tetramethylbisphenol A, bis(4-hydroxyphenyl)-p-diisopropylbenzene, hydroquinone, resorcinol, 4,4- Examples include dihydroxydiphenyl, and preferably bisphenol A. Further, it is also possible to use a compound in which one or more tetraalkylphosphonium sulfonates are bonded to the above-mentioned aromatic dihydroxy compound.

Among the polycarbonate resins mentioned above, aromatic polycarbonate resins derived from 2,2-bis(4-hydroxyphenyl)propane, or 2,2-bis(4-hydroxyphenyl)propane and other aromatic dihydroxy An aromatic polycarbonate copolymer derived from the compound is preferred. Alternatively, a copolymer mainly composed of an aromatic polycarbonate resin, such as a copolymer with a polymer or oligomer having a siloxane structure, may be used. Furthermore, two or more of the above-mentioned polycarbonate resins may be used in combination.

To adjust the molecular weight of polycarbonate resins, monovalent aromatic hydroxy compounds may be used, such as m- and p-methylphenol, m- and p-propylphenol, p-tert-butylphenol, p-long chain Examples include alkyl-substituted phenols.

The viscosity average molecular weight (Mv) of the polycarbonate resin is preferably 10,000 or more, more preferably 13,000 or more, most preferably more than 15,000. When a resin having a viscosity average molecular weight lower than 10,000 is used, the resulting resin composition tends to have low mechanical strength such as impact resistance. Moreover, Mv is preferably 60,000 or less, more preferably 40,000 or less, and even more preferably 35,000 or less. If it is higher than 60,000, the fluidity of the resin composition may become poor and moldability may deteriorate.

In the present invention, the viscosity average molecular weight (Mv) of the polycarbonate resin is determined by measuring the viscosity of a methylene chloride solution of the polycarbonate resin at 25°C using an Ubbelohde viscometer, and determining the intrinsic viscosity ([η]). The value calculated from the following Schnell's viscosity formula is shown.
[η]=1.23×10 ⁻⁴ Mv ^0.83

The method for producing polycarbonate resin is not particularly limited, and polycarbonate resin produced by either the phosgene method (interfacial polymerization method) or the melting method (ester exchange method) can be used. It is also preferable to use a polycarbonate resin produced by a melting method and subjected to a post-treatment to adjust the amount of terminal OH groups.

The styrene-maleic acid copolymer is preferably a styrene-maleic anhydride copolymer (SMA resin), which is a copolymer of styrene monomer and maleic anhydride monomer, and can be produced by radical polymerization or the like. Known polymerization methods are possible.

Although the molecular weight of the styrene-maleic acid copolymer is not particularly limited, the mass average molecular weight is preferably 10,000 or more and 500,000 or less, more preferably 40,000 or more and 400,000 or less, and Preferably it is 80,000 or more and 350,000.
The weight average molecular weight herein is the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent.

The styrene-maleic acid copolymer can be copolymerized with other monomer components within a range that does not impair the characteristics of the present invention. Specific examples include aromatic vinyl monomers such as α-methylstyrene, acrylonitrile, etc. vinyl cyanide monomers such as, unsaturated carboxylic acid alkyl ester monomers such as methyl methacrylate and methyl acrylate, N-methylmaleimide, N-ethylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, etc. These maleimide monomers can be used alone or in combination of two or more.

(D) The content of the compatibilizer is preferably 1 to 25 parts by mass, more preferably 3 parts by mass, based on a total of 100 parts by mass of (A) polybutylene terephthalate resin and (B) polystyrene resin or rubber-reinforced polystyrene resin. ~20 parts by weight, more preferably 3 to 18 parts by weight.

[(E) Glass fiber]
The polycarbonate resin composition of the present invention contains (E) glass fiber. Glass fibers that are normally used in thermoplastic polyester resins include A glass, E glass, alkali-resistant glass compositions containing zirconia components, chopped strands, roving glass, thermoplastic resin and glass fibers. Any known glass fiber can be used regardless of the form of the glass fiber when blending the masterbatch and the like. Among them, as the glass fiber used in the present invention, alkali-free glass (E glass) is preferable for the purpose of improving the thermal stability of the thermoplastic resin composition of the present invention.

(E) As the glass fiber, it is also preferable to use a glass fiber whose longitudinal cross-sectional shape ratio is in the range of 2.0 to 6.0.
The irregularity ratio of the longitudinal cross section is defined as a rectangle with the minimum area that circumscribes the cross section perpendicular to the length direction of the glass fiber, the length of the long side of this rectangle is the major axis, and the length of the short side is It is the ratio of the long axis/breadth axis when the short axis is the short axis.

In the present invention, (E) glass fiber exhibits a bridging function that connects the phases of (A) polybutylene terephthalate resin, and the polybutylene terephthalate resin tends to become a matrix (sea), so that it specifically The present inventor speculates that the heat resistance will be improved and the warpage property and appearance will be excellent.
Furthermore, when the glass fibers are present in a state surrounded by the (A) polybutylene terephthalate resin phase, the bridging effect between the (A) polybutylene terephthalate resin phases by the glass fibers is higher. In addition, since the bulky glass fibers play the role of an extender for the polybutylene terephthalate resin (A), it is thought that the heat resistance is further improved.

(E) The cross-sectional area of the glass fiber in the longitudinal direction is preferably more than 180 μm ² and 300 μm ² or less. With such a cross-sectional area, polybutylene terephthalate tends to form a matrix, resulting in poor heat resistance. Easy to improve. The cross-sectional area is more preferably more than 180 μm ² and less than 250 μm ² , and even more preferably more than 180 μm ² and less than 200 μm ² .
(E) The thickness of the glass fiber is not particularly limited, but it is preferable that the short axis is about 2 to 20 μm and the long axis is about 5 to 50 μm.

(E) The glass fibers may be treated with a sizing agent or a surface treatment agent. Furthermore, during the production of the resin composition of the present invention, a sizing agent or a surface treatment agent may be added to the untreated glass fibers for surface treatment.

Examples of the sizing agent include resin emulsions such as vinyl acetate resin, ethylene/vinyl acetate copolymer, acrylic resin, epoxy resin, polyurethane resin, and polyester resin.
Examples of surface treatment agents include aminosilane compounds such as γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, vinyltrichlorosilane, and methylvinyltrimethoxysilane. Chlorosilane compounds such as chlorosilane, alkoxysilane compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, γ-methacryloxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxy Examples include silane, epoxysilane compounds such as γ-glycidoxypropyltrimethoxysilane, acrylic compounds, isocyanate compounds, titanate compounds, and epoxy compounds.

Two or more of these sizing agents and surface treatment agents may be used in combination, and the amount used (adhered amount) is usually 10% by mass or less, preferably 0.05 to 10% by mass, based on the mass of (E) glass fiber. It is 5% by mass. By setting the adhesion amount to 10% by mass or less, necessary and sufficient effects can be obtained and it is economical.

(E) Two or more types of glass fibers may be used in combination depending on the required properties.

The preferred content of (E) glass fiber in the polycarbonate resin composition of the present invention is 10 to 150 parts by mass based on a total of 100 parts by mass of (A) polybutylene terephthalate resin and (B) polystyrene resin or rubber-reinforced polystyrene resin. It is. (E) If the content of glass fiber is less than 10 parts by mass, rigidity tends to be insufficient, and if it exceeds 150 parts by mass, impact resistance and fluidity tend to be insufficient, and production tends to be difficult. (E) The content of glass fiber is more preferably 20 parts by mass or more, more preferably 100 parts by mass or less, even more preferably 80 parts by mass or less, especially preferably 70 parts by mass or less, especially 60 parts by mass or less. In particular, it is preferably 55 parts by mass or less.

[Other inorganic fillers]
It is also preferable that the thermoplastic resin composition of the present invention contains other plate-like, granular, or amorphous inorganic fillers in addition to the glass fiber (E) described above. The plate-shaped inorganic filler exhibits the function of reducing anisotropy and warpage, and includes talc, glass flakes, mica, mica, kaolin, metal foil, and the like. Among the plate-shaped inorganic fillers, glass flakes are preferred.
Other granular or amorphous inorganic fillers include ceramic beads, clay, zeolite, barium sulfate, titanium oxide, silicon oxide, aluminum oxide, magnesium hydroxide, zinc sulfide, and the like.
As other inorganic fillers, talc, titanium oxide, and zinc sulfide are particularly preferred.

The content of other inorganic fillers is preferably 0.1 to 30 parts by mass, and more preferably 0.1 to 30 parts by mass, based on a total of 100 parts by mass of (A) polybutylene terephthalate resin and (B) polystyrene resin or rubber-reinforced polystyrene resin. Preferably it is 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 20 parts by mass.

[Stabilizer]
It is preferable for the thermoplastic resin composition of the present invention to contain a stabilizer because it has the effect of improving thermal stability and preventing deterioration of mechanical strength, transparency, and hue. As the stabilizer, phosphorus stabilizers, sulfur stabilizers and phenol stabilizers are preferred.

Examples of phosphorus stabilizers include phosphorous acid, phosphoric acid, phosphorous esters (phosphites), trivalent phosphoric esters (phosphonites), and pentavalent phosphoric esters (phosphates). Preferred are phyto compounds, organic phosphonite compounds, and organic phosphate compounds.

The organic phosphate compound preferably has the following general formula:
(R ¹ O) _3-n P(=O)OH _n
(In the formula, R ¹ is an alkyl group or an aryl group, and each may be the same or different. n represents an integer of 0 to 2.)
It is a compound represented by More preferred are long-chain alkyl acid phosphate compounds in which R ¹ has 8 to 30 carbon atoms. Specific examples of alkyl groups having 8 to 30 carbon atoms include octyl group, 2-ethylhexyl group, isooctyl group, nonyl group, isononyl group, decyl group, isodecyl group, dodecyl group, tridecyl group, isotridecyl group, tetradecyl group, Examples include hexadecyl group, octadecyl group, eicosyl group, and triacontyl group.

Examples of long-chain alkyl acid phosphates include octyl acid phosphate, 2-ethylhexyl acid phosphate, decyl acid phosphate, lauryl acid phosphate, octadecyl acid phosphate, oleyl acid phosphate, behenyl acid phosphate, phenyl acid phosphate, nonylphenyl acid phosphate, and cyclohexyl Acid phosphate, phenoxyethyl acid phosphate, alkoxypolyethylene glycol acid phosphate, bisphenol A acid phosphate, dimethyl acid phosphate, diethyl acid phosphate, dipropyl acid phosphate, diisopropyl acid phosphate, dibutyl acid phosphate, dioctyl acid phosphate, di-2-ethylhexyl acid phosphate, dioctyl acid phosphate, dilauryl acid phosphate, distearyl acid phosphate, diphenyl acid phosphate, bisnonylphenyl acid phosphate, and the like. Among these, octadecyl acid phosphate is preferred, and this product is commercially available from ADEKA under the trade name "ADEKA STAB AX-71".

The organic phosphite compound preferably has the following general formula:
R ² OP (OR ³ ) (OR ⁴ )
(In the formula, R ² , R ³ and R ⁴ are each a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, or an aryl group having 6 to 30 carbon atoms, and among R ² , R ³ and R ⁴ At least one of them is an aryl group having 6 to 30 carbon atoms.)
Examples include compounds represented by:

Examples of organic phosphite compounds include triphenyl phosphite, tris (nonylphenyl) phosphite, dilauryl hydrogen phosphite, triethyl phosphite, tridecyl phosphite, tris (2-ethylhexyl) phosphite, tris (tridecyl ) Phosphite, tristearyl phosphite, diphenyl monodecyl phosphite, monophenyl didecyl phosphite, diphenyl mono(tridecyl) phosphite, tetraphenyldipropylene glycol diphosphite, tetraphenyltetra(tridecyl)pentaerythritol tetraphosphite , hydrogenated bisphenol A phenol phosphite polymer, diphenyl hydrogen phosphite, 4,4'-butylidene-bis(3-methyl-6-tert-butylphenyl di(tridecyl) phosphite), tetra(tridecyl)4,4 '-isopropylidene diphenyl diphosphite, bis(tridecyl) pentaerythritol diphosphite, bis(nonylphenyl) pentaerythritol diphosphite, dilauryl pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, tris(4- tert-butylphenyl) phosphite, tris(2,4-di-tert-butylphenyl) phosphite, hydrogenated bisphenol A pentaerythritol phosphite polymer, bis(2,4-di-tert-butylphenyl) pentaerythritol di Phosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,2'-methylenebis(4,6-di-tert-butylphenyl)octylphosphite, bis( Examples include 2,4-dicumylphenyl) pentaerythritol diphosphite. Among these, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite is preferred.

The organic phosphonite compound preferably has the following general formula:
^R5 -P( ^OR6 )( ^OR7 )
(In the formula, R ⁵ , R ⁶ and R ⁷ are each a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, or an aryl group having 6 to 30 carbon atoms, and among R ⁵ , R ⁶ and R ⁷ At least one of them is an aryl group having 6 to 30 carbon atoms.)
Examples include compounds represented by:

Examples of organic phosphonite compounds include tetrakis(2,4-di-iso-propylphenyl)-4,4'-biphenylene diphosphonite, tetrakis(2,4-di-n-butylphenyl)-4,4'-biphenylphenyl Diphosphonite, Tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite, Tetrakis(2,4-di-tert-butylphenyl)-4,3'-biphenylene diphosphonite Tetrakis (2,4-di-tert-butylphenyl)-3,3'-biphenylene diphosphonite, Tetrakis (2,6-di-iso-propylphenyl)-4,4'-biphenylene diphosphonite, Tetrakis (2,6-di-n-butylphenyl)-4,4'-biphenylene diphosphonite, Tetrakis (2,6-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite, Tetrakis ( Examples include 2,6-di-tert-butylphenyl)-4,3'-biphenylene diphosphonite and tetrakis(2,6-di-tert-butylphenyl)-3,3'-biphenylene diphosphonite. .

As the sulfur stabilizer, any conventionally known sulfur atom-containing compound can be used, and thioethers are preferred among them. Specifically, for example, didodecylthiodipropionate, ditetradecylthiodipropionate, dioctadecylthiodipropionate, pentaerythritol tetrakis (3-dodecylthiopropionate), thiobis(N-phenyl-β-naphthylamine) ), 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, tetramethylthiuram monosulfide, tetramethylthiuram disulfide, nickel dibutyl dithiocarbamate, nickel isopropyl xanthate, and trilauryl trithiophosphite. Among these, pentaerythritol tetrakis (3-dodecylthiopropionate) is preferred.

Examples of phenolic stabilizers include pentaerythritol tetrakis (3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate), octadecyl-3-(3,5-di-tert-butyl-4 -hydroxyphenyl)propionate, thiodiethylene bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), pentaerythritol tetrakis(3-(3,5-di-neopentyl-4-hydroxyphenyl) ) propionate), etc. Among these, pentaerythritol tetrakis (3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) ) Propionate is preferred.

One type of stabilizer may be contained, or two or more types may be contained in any combination and ratio.

The content of the stabilizer is preferably 0.001 to 2 parts by weight based on a total of 100 parts by weight of (A) polybutylene terephthalate resin and (B) polystyrene resin or rubber-reinforced polystyrene resin. If the content of the stabilizer is less than 0.001 parts by mass, it is difficult to expect improvement in the thermal stability and compatibility of the resin composition, and a decrease in molecular weight and deterioration of hue during molding are likely to occur. If it exceeds the amount, there is a tendency that the amount becomes excessive and silver formation and hue deterioration are more likely to occur. The content of the stabilizer is more preferably 0.01 to 1.5 parts by mass, and even more preferably 0.1 to 1 part by mass.

[Release agent]
It is preferable that the thermoplastic resin composition of the present invention contains a mold release agent. As the mold release agent, known mold release agents commonly used for polyester resins can be used, but among them, polyolefin compounds and fatty acid ester compounds are preferable because of their good alkali resistance.In particular, polyolefin compounds and fatty acid ester compounds are preferred. Compounds are preferred.

Examples of the polyolefin compound include compounds selected from paraffin wax and polyethylene wax, and among them, those having a weight average molecular weight of 700 to 10,000, more preferably 900 to 8,000.

Examples of fatty acid ester compounds include fatty acid esters such as saturated or unsaturated monovalent or divalent aliphatic carboxylic acid esters, glycerin fatty acid esters, sorbitan fatty acid esters, and partially saponified products thereof. Among these, mono- or di-fatty acid esters composed of a fatty acid having 11 to 28 carbon atoms, preferably 17 to 21 carbon atoms, and alcohol are preferred.

Examples of fatty acids include palmitic acid, stearic acid, caproic acid, capric acid, lauric acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, melisic acid, tetraliacontanoic acid, montanic acid, adipic acid, azelaic acid, etc. It will be done. Furthermore, the fatty acid may be alicyclic.
Alcohols include saturated or unsaturated monohydric or polyhydric alcohols. These alcohols may have a substituent such as a fluorine atom or an aryl group. Among these, monohydric or polyhydric saturated alcohols having 30 or less carbon atoms are preferred, and aliphatic saturated monohydric or polyhydric alcohols having 30 or less carbon atoms are more preferred. Here, aliphatic also includes alicyclic compounds.
Specific examples of such alcohols include octanol, decanol, dodecanol, stearyl alcohol, behenyl alcohol, ethylene glycol, diethylene glycol, glycerin, pentaerythritol, 2,2-dihydroxyperfluoropropanol, neopentylene glycol, ditrimethylolpropane, dipentaerythritol, and the like. can be mentioned.
Note that the above ester compound may contain an aliphatic carboxylic acid and/or an alcohol as an impurity, or may be a mixture of a plurality of compounds.

Specific examples of fatty acid ester compounds include glycerin monostearate, glycerin monobehenate, glycerin dibehenate, glycerin-12-hydroxy monostearate, sorbitan monobehenate, pentaerythritol monostearate, and pentaerythritol dibehenate. Examples include stearate, stearyl stearate, ethylene glycol montanate, and the like.

The content of the mold release agent is preferably 0.1 to 3 parts by mass, but 0.1 to 3 parts by mass, based on a total of 100 parts by mass of (A) polybutylene terephthalate resin and (B) polystyrene resin or rubber-reinforced polystyrene resin. It is more preferably 2 to 2.5 parts by weight, and even more preferably 0.3 to 2 parts by weight. If it is less than 0.1 part by mass, the surface properties tend to decrease due to poor mold release during melt molding, while if it exceeds 3 parts by mass, the kneading workability of the resin composition tends to decrease, and the molded product The surface tends to become cloudy.

[Carbon black]
The thermoplastic resin composition of the present invention preferably contains carbon black.
There are no restrictions on the type, raw material, or manufacturing method of carbon black, and any of furnace black, channel black, acetylene black, Ketjen black, etc. can be used. There is no particular restriction on the number average particle diameter, but it is preferably about 5 to 60 nm.

Preferably, the carbon black is formulated as a masterbatch premixed with a thermoplastic resin, preferably a polybutylene terephthalate resin.

The content of carbon black is preferably 0.1 to 4 parts by mass, more preferably 0.2 to 4 parts by mass, based on a total of 100 parts by mass of (A) polybutylene terephthalate resin and (B) polystyrene resin or rubber-reinforced polystyrene resin. 3 parts by mass. If it is less than 0.1 parts by mass, the desired color may not be obtained or the effect of improving weather resistance may not be sufficient, and if it exceeds 4 parts by mass, mechanical properties may deteriorate.

[Other ingredients]
The thermoplastic resin composition of the present invention may contain thermoplastic resins other than the above-mentioned essential components within a range that does not impair the effects of the present invention. Other thermoplastic resins include, for example, polyacetal resins, polyamide resins, polyphenylene oxide resins, polyphenylene sulfide resins, polysulfone resins, polyethersulfone resins, polyetherimide resins, polyetherketone resins, and polyolefin resins. etc.
However, when containing other resins, the content is preferably 20 parts by mass or less based on a total of 100 parts by mass of (A) polybutylene terephthalate resin and (B) polystyrene resin or rubber-reinforced polystyrene resin. It is more preferably 10 parts by mass or less, more preferably 5 parts by mass or less, particularly preferably 3 parts by mass or less.

Furthermore, the thermoplastic resin composition of the present invention may contain various additives other than those described above, and such additives include flame retardants, flame retardant aids, anti-dripping agents, and ultraviolet absorbers. agents, antistatic agents, antifogging agents, antiblocking agents, plasticizers, dispersants, antibacterial agents, colorants, dyes and pigments, etc.

[Manufacture of thermoplastic resin composition]
The thermoplastic resin composition of the present invention can be produced according to conventional methods for preparing resin compositions. That is, (A) polybutylene terephthalate resin, (B) polystyrene resin or rubber-reinforced polystyrene resin, and (C) epoxy group-containing compound, as well as other resin components and various additives added as desired, are mixed together thoroughly. Then, the mixture is melt-kneaded using a single-screw or twin-screw extruder. Alternatively, the resin composition can also be prepared by pre-mixing each component or only a part of the components, feeding the mixture to an extruder using a feeder, and melt-kneading the mixture. (E) It is preferable to side feed the glass fibers.
Alternatively, a part of the mixture may be blended into a masterbatch and melt-kneaded. Furthermore, it is also possible to produce various molded products by supplying a mixture obtained by mixing each component in advance to a molding machine such as an injection molding machine as it is without melt-kneading it.

The heating temperature during melt-kneading can be selected as appropriate from the range of usually 220 to 300°C. If the temperature is too high, decomposition gas is likely to be generated, which may cause poor appearance. Therefore, it is desirable to select a screw configuration that takes shear heat generation into consideration. In order to suppress decomposition during kneading and subsequent molding, it is desirable to use antioxidants and heat stabilizers.

[Molded object]
The method for producing a molded article using the thermoplastic resin composition of the present invention is not particularly limited, and any molding method generally employed for thermoplastic resin compositions can be employed. Examples include injection molding, ultra-high-speed injection molding, injection compression molding, two-color molding, gas-assisted blow molding, molding using an insulated mold, and rapid heating mold. Molding method, foam molding (including supercritical fluid), insert molding, IMC (in-mold coating molding) molding method, extrusion molding method, sheet molding method, thermoforming method, rotational molding method, lamination molding method, press molding method, Examples include blow molding method. Among these, the injection molding method is preferable because the effects of the present invention are remarkable, such as productivity and good surface properties of the molded product obtained.

The obtained molded product has excellent heat resistance, low warping property, and chemical resistance, and is therefore suitably used as electrical and electronic equipment parts, interior and exterior parts for automobiles, and other electrical parts that require these properties strictly. Particularly suitable for interior and exterior parts of automobiles, such as casings for equipment parts installed in automobiles, casings for head-up displays installed in automobiles, casings for engine control units (ECU), etc. It can be particularly suitably used.

Hereinafter, the present invention will be explained in more detail with reference to Examples. However, the present invention is not interpreted as being limited to the following examples.
In the following Examples and Comparative Examples, the components used are as shown in Table 1 below.

(Examples 1 to 4, Comparative Examples 1 to 8)
Among the components shown in Table 1 above, each component excluding glass fiber was mixed uniformly in a tumbler mixer at the proportions shown in Table 2 below (all parts by mass), and then mixed using a twin screw extruder (Japan Steel The resin composition was melted and kneaded using "TEX30α" (L/D = 42) manufactured by Co., Ltd., with the glass fibers supplied from the side feeder, under the conditions of a cylinder set temperature of 260 ° C., a discharge rate of 40 kg/h, and a screw rotation speed of 200 rpm. was rapidly cooled in a water tank and pelletized using a pelletizer to obtain pellets of a thermoplastic resin composition.

[Tensile strength at break, tensile elongation at break]
After drying the pellets obtained above at 120°C for 5 hours, using an injection molding machine manufactured by Nippon Steel Corporation (mold clamping force 85T), ISO multi-purpose Test pieces (4 mm thick) were injection molded.
Based on ISO527, the tensile strength at break (unit: MPa) and tensile elongation at break (unit: %) were measured using the above ISO multipurpose test piece (4 mm thickness).
[Maximum bending strength, bending modulus]
In accordance with ISO 178, maximum bending strength (unit: MPa) and bending elastic modulus (unit: MPa) were measured at a temperature of 23° C. using the above ISO multipurpose test piece (4 mm thickness).
[Notched Charpy impact strength]
In accordance with ISO 179, the notched Charpy impact strength (unit: kJ/m ² ) of the above-mentioned ISO multi-purpose test piece (4 mm thick) was measured at a temperature of 23° C. with a notch.

[Deflection temperature under load and heat resistance judgment]
Using the above ISO multipurpose test piece (4 mm thick), the deflection temperature under load was measured under a load of 1.80 MPa in accordance with ISO75-1 and ISO75-2.
Heat resistance was evaluated based on the following criteria.
○: Deflection temperature under load is 140℃ or more ×: Deflection temperature under load is less than 140℃

[Warpage amount and warpability judgment]
A circular plate with a diameter of 100 mm and a thickness of 1.6 mm was molded using an injection molding machine (NEX80 manufactured by Nissei Jushi Kogyo Co., Ltd.) using a side gate mold at a cylinder temperature of 260°C and a mold temperature of 80°C. The amount of warpage (unit: mm) of the plate was determined.
Warpability was evaluated based on the following strict criteria.
○: The amount of warpage is less than 1mm ×: The amount of warpage is 1mm or more

[Tensile strength retention rate (unit: %) and hydrolysis resistance judgment]
Using an injection molding machine "NEX80-9E" manufactured by Nissei Jushi Kogyo Co., Ltd., an ISO test piece was prepared at a cylinder temperature of 250°C and a mold temperature of 80°C, and a tensile test was conducted in accordance with ISO527.
Furthermore, the above-mentioned ISO test piece was subjected to moist heat treatment (PCT test) in saturated steam at a temperature of 121° C. and a pressure of 203 kPa for 50 hours. The tensile strength of the ISO test pieces before and after the moist heat treatment was measured in accordance with ISO527.
The tensile strength retention rate (unit: %) was determined from the following formula.
Tensile strength retention rate (%) = (Tensile strength after treatment/Tensile strength before treatment) x 100
Hydrolysis resistance was evaluated based on the following criteria.
○: Tensile strength retention rate is 60% or more ×: Tensile strength retention rate is less than 60%

The above results are shown in Table 2 below.

The thermoplastic resin composition of the present invention has an extremely low warpage property, excellent hydrolysis resistance, excellent heat resistance, and excellent mechanical strength, so it can be used in electrical and electronic equipment where these properties are strictly required. It can be particularly suitably used as parts, interior and exterior parts for automobiles, and other electrical components.

Claims (7)

(A) 10 to 50 parts by mass of polybutylene terephthalate resin with an intrinsic viscosity (IV) of 0.3 to 0.8 dl/g, (B) a melt viscosity (η) of 80 at 250°C and 912 sec ^-1 . 50 to 90 parts by mass of a rubber-reinforced polystyrene resin having a pressure of ~500 Pa·sec, and (C) an epoxy group-containing compound having a weight average molecular weight of 200 to 10,000, for a total of 100 parts by mass of the above (A) and (B). 0.1 to 5 parts by mass based on the thermoplastic resin composition. The thermoplastic resin composition according to claim 1, wherein the weight average molecular weight and epoxy equivalent of the epoxy group-containing compound (C) satisfy the following formula.
1.5<[weight average molecular weight of (C)/epoxy equivalent of (C)]<50 The thermoplastic resin composition according to claim 1 or 2, further comprising (D) a compatibilizer in an amount of 1 to 25 parts by mass based on a total of 100 parts by mass of the (A) and (B). The thermoplastic resin composition according to any one of claims 1 to 3, wherein the terminal carboxyl group concentration of the polybutylene terephthalate resin (A) is 0.1 to 30 eq/ton. The thermoplastic resin composition according to any one of claims 1 to 4, further comprising (E) glass fiber in an amount of 10 to 150 parts by mass based on a total of 100 parts by mass of (A) and (B). A molded article made of the thermoplastic resin composition according to any one of claims 1 to 5. 7. The molded article according to claim 6, wherein the molded article is a casing for an equipment component mounted on an automobile.