JP7262282B2 - Thermoplastic resin composition and molded article - Google Patents

Description

TECHNICAL FIELD The present invention relates to a thermoplastic resin composition and a molded article, and more particularly to a thermoplastic resin composition having high heat resistance, low warpage and excellent mechanical strength, and a molded article made of the same.

Thermoplastic polyester resins represented by polybutylene terephthalate resin and polyethylene terephthalate resin are excellent in mechanical strength, chemical resistance, electrical insulation, etc. Widely used for machine parts.

However, since polybutylene terephthalate resin is a crystalline resin, it has a large molding shrinkage rate. Especially when a reinforcing filler such as glass fiber is blended, the anisotropy tends to increase, and the molded product warps. Sometimes. Therefore, in order to reduce warpage, a method of mixing various amorphous resins has been proposed.

In Patent Document 1, (a) polyester resin 50 to 96% by weight, (b) rubber-modified polystyrene resin 35 to 3% by weight, (c) aromatic polycarbonate resin and/or styrene-maleic anhydride copolymer 15 to A polyester resin composition obtained by blending (B) a glass fiber having a sizing agent containing an amino silane coupling agent and a novolak type epoxy resin attached to a resin (A) consisting of 1% by weight and (C) an epoxy compound is flowed. 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.

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

JP 2006-16559 A JP 2007-314619 A

An object (subject) of the present invention is to provide a thermoplastic resin composition having high heat resistance, low warpage property and excellent mechanical strength, and a molded article made of the composition.

As a result of intensive studies to solve the above-described problems, the present inventors have found that when combining a low-molecular-weight polybutylene terephthalate resin and a high-molecular-weight polystyrene resin or rubber-reinforced polystyrene resin (HIPS), the amount of polybutylene terephthalate resin is reduced. By increasing the amount of polystyrene resin or HIPS and by containing carbon fiber, the low-molecular-weight polybutylene terephthalate resin achieves high heat resistance, which is a characteristic of polybutylene terephthalate resin, even though the amount is small. The present inventors have reached the present invention by discovering that a resin composition having excellent warpage resistance is obtained.
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; 50 to 90 parts by mass of polystyrene resin or rubber-reinforced polystyrene resin having a viscosity of up to 500 Pa·sec, and (C) 5 to 100 parts by mass of carbon fiber with respect to the total of 100 parts by mass of (A) and (B). A thermoplastic resin composition characterized by:
[2] The thermoplastic resin composition according to [1] above, further comprising (D) a compatibilizer in an amount of 1 to 30 parts by mass with respect to a total of 100 parts by mass of (A) and (B).
[3] (C) The thermoplastic resin composition according to the above [1] or [2], wherein the carbon fibers have an average fiber diameter of 10 μm or less.
[4] The thermoplastic resin composition according to any one of [1] to [3] above, which has a specific gravity in the range of 1.0 to 1.33.
[5] A molded article made of the thermoplastic resin composition according to any one of [1] to [4] above.
[6] The molded article according to [5] above, which is a connector part for electrical equipment of automobiles.
[7] The molded article according to [5] above, which is a housing for a head-up display or an engine control unit.

Surprisingly, the thermoplastic resin composition of the present invention selectively uses a low molecular weight polybutylene terephthalate resin in spite of a system rich in polystyrene resin or rubber-reinforced polystyrene resin, which is low in polybutylene terephthalate resin. And by containing carbon fibers, the resin phase of the polybutylene terephthalate resin becomes continuous through the carbon fibers, making it easier to become a matrix (sea), and the polystyrene resin or rubber-reinforced polystyrene resin with high melt viscosity becomes an island. As a result, the heat resistance is specifically improved, the low warpage property is excellent, and the mechanical strength is also excellent.
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.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail. Although the explanations described below may be made based on embodiments and specific examples, the present invention should not be construed as being limited to such embodiments and specific examples.
In the present specification, when a range is indicated by using "-" and sandwiching it between numerical values or physical property values, it means a range including the values before and after it.

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) 50 to 90 parts by mass of a polystyrene resin or rubber-reinforced polystyrene resin having a melt viscosity of 80 to 500 Pa·sec at 250°C and 912 sec ^-1 ;
(C) 5 to 100 parts by mass of carbon fiber per 100 parts by mass in total of (A) and (B).

[(A) Polybutylene terephthalate resin]
The thermoplastic resin composition of the present invention contains (A) a polybutylene terephthalate resin having an intrinsic viscosity (IV) of 0.3 to 0.8 dl/g.
By using those having an intrinsic viscosity (IV) in the range of 0.3 to 0.8 dl / g, the characteristics of polybutylene terephthalate resin are strongly manifested, excellent in high heat resistance and low warpage, and mechanical strength and The resin composition also has excellent chemical resistance.
If the intrinsic viscosity (IV) is lower than 0.3 dl/g, the heat resistance of polybutylene terephthalate is not exhibited and the mechanical strength tends to be low. If it is higher than 0.8 dl/g, it becomes difficult to form the sea-island structure described above, and (B) the polystyrene resin or rubber-reinforced polystyrene resin tends to form a sea, and the flowability of the resin composition deteriorates, resulting in poor moldability. Easy to wear. 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 (A) polybutylene terephthalate resin is a value measured at 30° C. in a 1:1 (mass ratio) mixed solvent of tetrachloroethane and phenol.

(A) Polybutylene terephthalate resin is a polyester resin having a structure in which terephthalic acid units and 1,4-butanediol units are ester-linked, and in addition to polybutylene terephthalate resin (homopolymer), terephthalic acid units and 1 ,4-butanediol units, polybutylene terephthalate copolymers containing other copolymerization components, and mixtures of homopolymers and such copolymers.

(A) The polybutylene terephthalate resin may contain dicarboxylic acid units other than terephthalic acid. Specific examples of other dicarboxylic acids include isophthalic acid, orthophthalic acid, 1,5-naphthalene dicarboxylic acid, 2,5 -naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, biphenyl-2,2'-dicarboxylic acid, biphenyl-3,3'-dicarboxylic acid, biphenyl-4,4'-dicarboxylic acid, bis(4,4'- carboxyphenyl)methane, anthracenedicarboxylic acid, 4,4′-diphenylether dicarboxylic acid and other aromatic dicarboxylic acids; 1,4-cyclohexanedicarboxylic acid, 4,4′-dicyclohexyldicarboxylic acid and other alicyclic dicarboxylic acids; 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 above bifunctional monomers, trifunctional monomers such as trimellitic acid, trimesic acid, pyromellitic acid, pentaerythritol, and trimethylolpropane for introducing a branched structure, and fatty acids for molecular weight adjustment. A small amount of monofunctional compound can also be used together.

As described above, the polybutylene terephthalate resin (A) is preferably a polybutylene terephthalate homopolymer obtained by polycondensation of terephthalic acid and 1,4-butanediol. A polybutylene terephthalate copolymer containing one or more diols other than the 1,4-butanediol may be used as one or more dicarboxylic acid and/or diol units, and (A) the polybutylene terephthalate resin is a copolymer In the case of a polybutylene terephthalate resin modified by polymerization, specific preferred copolymers thereof include polyester ether resins obtained by copolymerizing polyalkylene glycols, particularly polytetramethylene glycol, and polybutylene terephthalate copolymerized with dimer acid. resins, and isophthalic acid-copolymerized polybutylene terephthalate resins.
In addition, these copolymers refer to those having a copolymerization amount of 1 mol % or more and less than 50 mol % in all segments of the polybutylene terephthalate resin. Among them, the copolymerization amount is preferably 2 mol % or more and less than 50 mol %, more preferably 3 to 40 mol %, particularly preferably 5 to 20 mol %. By setting such a copolymerization ratio, fluidity and toughness tend to be improved, which is preferable.

(A) Polybutylene terephthalate resin, the amount of terminal carboxyl groups may be appropriately selected and determined, but it is usually 60 eq/ton or less, preferably 50 eq/ton or less, and 30 eq/ton or less. is more preferred. If it exceeds 60 eq/ton, the alkali resistance and hydrolysis resistance are lowered, and gas tends to be generated during melt molding of the resin composition. Although the lower limit of the amount of terminal carboxyl groups is not particularly defined, it is usually 10 eq/ton in consideration of productivity in the production of polybutylene terephthalate resin.

The terminal carboxyl group content of the polybutylene terephthalate resin is a value measured by dissolving 0.5 g of the polyalkylene terephthalate resin in 25 mL of benzyl alcohol and titrating with a 0.01 mol/l benzyl alcohol solution of sodium hydroxide. be. As a method for adjusting the amount of terminal carboxyl groups, any conventionally known method may be used, such as a method of adjusting polymerization conditions such as the raw material charge ratio during polymerization, the polymerization temperature, and a decompression method, or a method of reacting a terminal blocking agent. You can do it.

(A) Polybutylene terephthalate resin is obtained by melt-polymerizing a dicarboxylic acid component or ester derivative thereof mainly composed of terephthalic acid and a diol component mainly composed of 1,4-butanediol in a batch or continuous manner. can be manufactured by Further, after producing a low-molecular-weight polybutylene terephthalate resin by melt polymerization, the degree of polymerization (or molecular weight) can be increased to a desired value by solid-phase polymerization under a nitrogen stream or under reduced pressure.
(A) Polybutylene terephthalate resin is obtained by a production method in which a dicarboxylic acid component containing terephthalic acid as a main component and a diol component containing 1,4-butanediol as a main component are continuously subjected to melt polycondensation. is preferred.

Catalysts used in carrying out the esterification reaction may be those conventionally known, and examples thereof include titanium compounds, tin compounds, magnesium compounds, calcium compounds, and the like. Particularly suitable among these are titanium compounds. Specific examples of the titanium compound as the 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 or a rubber-reinforced polystyrene resin.
The polystyrene resin may be a homopolymer of styrene or a copolymer obtained by copolymerizing other aromatic vinyl monomers such as α-methylstyrene, paramethylstyrene, vinyltoluene, vinylxylene, etc., in a range of 50% by mass or less. There may be.

The rubber-reinforced polystyrene resin is preferably copolymerized or blended with a butadiene-based rubber component, and the amount of the butadiene-based 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 mass, more preferably 5 to 20% by mass.
High impact polystyrene (HIPS) is particularly preferred as the rubber-reinforced polystyrene resin.

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

(B) The melt viscosity (η) of the polystyrene resin or rubber-reinforced polystyrene resin is preferably 90 Pa·sec or more, more preferably 100 Pa·sec or more, still more preferably 110 Pa·sec or more, especially 120 Pa·sec or more, particularly 130 Pa. • It is preferable that the time is greater than or equal to sec. Further, 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, more preferably 180 Pa·sec or less, particularly preferably 160 Pa·sec or less.
The melt viscosity can be measured according to ISO 11443 using a capillary rheometer and a slit die rheometer.

As described above, the content of (A) polybutylene terephthalate resin is 10 to 50 parts by mass based on a total of 100 parts by mass of (A) and (B), and (B) polystyrene resin or rubber-reinforced polystyrene resin is 50 to 50 parts by mass. Although it is 90 parts by mass, preferably (A) is 20 parts by mass or more and less than 50 parts by mass, more preferably 25 parts by mass or more and less than 50 parts by mass, still more preferably 30 parts by mass or more and less than 50 parts by mass, particularly preferably 30 parts by mass. ~ 48 parts by mass, and (B) is preferably more than 50 parts by mass and 80 parts by mass or less, more preferably more than 50 parts by mass and 75 parts by mass or less, still more preferably more than 50 parts by mass and 70 parts by mass or less, particularly preferably 52 parts by mass ~70 parts by mass.

[(C) Carbon fiber]
The polycarbonate resin composition of the present invention contains (C) carbon fibers. (C) As the carbon fiber, any of PAN (polyacrylonitrile), pitch, rayon and the like can be used. Among them, PAN-based carbon fibers are preferable.

(C) The average fiber diameter of carbon fibers is preferably 10 μm or less from the viewpoint of mechanical strength, and most preferably in the range of 5 to 8 μm from the viewpoint of balance between fluidity and appearance.
In addition, the number average fiber length of the (C) carbon fibers is preferably 0.2 mm or more, more preferably 0.4 mm or more, and the upper limit of the number average fiber length is preferably 10 mm or less, more preferably 8 mm or less. , 7 mm or less, and particularly preferably 6 mm or less.

(C) The carbon fiber is preferably surface-treated, and the tensile strength and bending strength of the resin composition are improved. Any commonly used surface treatment agent can be used, and examples thereof include epoxy sizing agents, urethane sizing agents, epoxy-urethane sizing agents, polyamide sizing agents, and olefin sizing agents. Among these, epoxy-based, polyamide-based, and urethane-based materials are preferred.
The amount of the surface treatment agent (C) is preferably in the range of 0.5 to 15 parts by mass, more preferably in the range of 1 to 10 parts by mass, per 100 parts by mass of the carbon fiber.

The content of (C) carbon fiber in the polycarbonate resin composition of the present invention is 5 to 100 parts by mass with respect to a total of 100 parts by mass of (A) polybutylene terephthalate resin and (B) polystyrene resin or rubber-reinforced polystyrene resin. be. (C) If the carbon fiber content is less than 5 parts by mass, the rigidity will be insufficient. (C) The content of the carbon fiber is preferably 10 parts by mass or more, preferably 80 parts by mass or less, more preferably 60 parts by mass or less, still more preferably 50 parts by mass or less, especially 40 parts by mass or less, especially It is preferably 30 parts by mass or less.

[Glass fiber]
The thermoplastic resin composition of the present invention may further contain glass fibers.
As the glass fiber, if it is usually used for thermoplastic polyester resin, A glass, E glass, alkali resistant glass composition containing zirconia component, chopped strand, roving glass, thermoplastic resin and glass fiber Any known glass fiber can be used regardless of the form of the glass fiber at the time of blending the masterbatch or 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.

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

Examples of the sizing agent include resin emulsions such as vinyl acetate resins, ethylene/vinyl acetate copolymers, acrylic resins, epoxy resins, polyurethane resins and polyester resins.
Examples of surface treatment agents include aminosilane compounds such as γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane; vinyltrichlorosilane; Chlorosilane compounds such as chlorosilane, alkoxysilane compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, γ-methacryloxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxy Epoxysilane-based compounds such as silane, γ-glycidoxypropyltrimethoxysilane, acrylic compounds, isocyanate-based compounds, titanate-based compounds, and epoxy-based compounds are included.
Two or more of these sizing agents and surface treatment agents may be used in combination, and the amount used (adhesion amount) is usually 10% by mass or less, preferably 0.05 to 5% by mass, based on the mass of the glass fiber. is. By setting the adhesion amount to 10% by mass or less, necessary and sufficient effects can be obtained, which is economical.

When glass fiber is contained, the content is preferably 5 to 150 parts by mass, more preferably 10 parts by mass, relative to a total of 100 parts by mass of (A) polybutylene terephthalate resin and (B) polystyrene resin or rubber-reinforced polystyrene resin. 120 parts by mass, preferably 15 to 100 parts by mass, particularly preferably 20 to 90 parts by mass, most preferably 30 to 80 parts by mass.

[Other inorganic fillers]
The thermoplastic resin composition of the present invention preferably contains other inorganic fillers in the form of plates, granules, or amorphous, in addition to (C) the carbon fibers and glass fibers described above. The plate-like inorganic filler exhibits the function of reducing anisotropy and warpage, and examples thereof include talc, glass flakes, mica, mica, kaolin, and metal foil. Glass flakes are preferred among the plate-like inorganic fillers.
Other particulate or amorphous inorganic fillers include ceramic beads, clays, zeolites, barium sulfate, titanium oxide, silicon oxide, aluminum oxide, magnesium hydroxide, zinc sulfide, and the like.
Talc, titanium oxide, and zinc sulfide are particularly preferred as other inorganic fillers.

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

[(D) compatibilizer]
The thermoplastic resin composition of the present invention preferably further contains (D) a compatibilizer. By containing (D) a compatibilizer, (A) polybutylene terephthalate resin and (B) polystyrene resin or rubber-reinforced polystyrene resin are accelerated to compatibilize, thereby dispersing in (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 becomes higher, so that excellent mechanical strength and excellent appearance can be easily obtained.

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

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

Polycarbonate resins are optionally branched thermoplastic polymers or copolymers obtained by reacting a dihydroxy compound or a small amount of a polyhydroxy compound with phosgene or a carbonic acid diester.

The raw material dihydroxy compound does not substantially contain a bromine atom, and is preferably an aromatic dihydroxy compound. Specifically, 2,2-bis(4-hydroxyphenyl)propane (that is, bisphenol A), tetramethylbisphenol A, bis(4-hydroxyphenyl)-p-diisopropylbenzene, hydroquinone, resorcinol, 4,4- Examples include dihydroxydiphenyl and the like, preferably bisphenol A. A compound in which one or more tetraalkylphosphonium sulfonates are bonded to the above aromatic dihydroxy compound can also be used.

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 Aromatic polycarbonate copolymers derived from a compound are preferred. It may also be a copolymer mainly composed of an aromatic polycarbonate resin, such as a copolymer with a polymer or oligomer having a siloxane structure. Furthermore, two or more of the above polycarbonate resins may be mixed and used.

Monohydric aromatic hydroxy compounds may be used to control the molecular weight of polycarbonate resins, such as m- and p-methylphenol, m- and p-propylphenol, p-tert-butylphenol, p-long chain Alkyl-substituted phenols and the like can be mentioned.

The viscosity average molecular weight (Mv) of the polycarbonate resin is preferably 10,000 or more, more preferably 13,000 or more, and most preferably more than 15,000. If the viscosity-average molecular weight is lower than 10,000, the resulting resin composition tends to have low mechanical strength such as impact resistance. Also, 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 deteriorate and the moldability may deteriorate.

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

The method for producing the polycarbonate resin is not particularly limited, and polycarbonate resins produced by either the phosgene method (interfacial polymerization method) or the melt method (transesterification method) can be used. Also preferred is a polycarbonate resin prepared by subjecting a polycarbonate resin produced by a melting method to a post-treatment for adjusting 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 a styrene monomer and a maleic anhydride monomer. Known polymerization methods are possible.

The molecular weight and the like of the styrene-maleic acid copolymer are not particularly limited. Preferably it is 80,000 or more and 350,000.
Here, the mass average molecular weight is the polystyrene-equivalent mass average molecular weight measured by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent.

Other monomer components can be copolymerized with the styrene-maleic acid copolymer as long as the properties of the present invention are not impaired. vinyl cyanide-based monomers, unsaturated carboxylic acid alkyl ester-based monomers such as methyl methacrylate and methyl acrylate, N-methylmaleimide, N-ethylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, etc. and the like, and these can be used alone or in combination of two or more.

The content of the (D) compatibilizer is preferably 1 to 30, either alone or in total, with respect to a total of 100 parts by mass of (A) polybutylene terephthalate resin and (B) polystyrene resin or rubber-reinforced polystyrene resin. parts by mass, more preferably 1 to 25 parts by mass, still more preferably 3 to 20 parts by mass, and particularly preferably 3 to 18 parts by mass.

[Stabilizer]
It is preferable that the thermoplastic resin composition of the present invention contain a stabilizer because it has effects of improving thermal stability and preventing deterioration of mechanical strength, transparency and hue. Phosphorus-based stabilizers, sulfur-based stabilizers and phenol-based stabilizers are preferred as stabilizers.

Phosphorus-based stabilizers include phosphorous acid, phosphoric acid, phosphites (phosphites), trivalent phosphates (phosphonites), pentavalent phosphates (phosphates) and the like, among which phosphites , phosphonites and phosphates are preferred.

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, which may be the same or different. n represents an integer of 0 to 2.)
It is a compound represented by More preferably, R ¹ is a long-chain alkyl acid phosphate compound having 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, A hexadecyl group, an octadecyl group, an eicosyl group, a triacontyl group and the like can be mentioned.

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, 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 )
(wherein 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 is an aryl group having 6 to 30 carbon atoms.)
The compound represented by is mentioned.

Examples of organic phosphite compounds include triphenylphosphite, tris(nonylphenyl)phosphite, dilaurylhydrogenphosphite, triethylphosphite, tridecylphosphite, tris(2-ethylhexyl)phosphite, tris(tridecyl ) phosphite, tristearyl phosphite, diphenyl monodecyl phosphite, monophenyl didecyl phosphite, diphenyl mono (tridecyl) phosphite, tetraphenyl dipropylene glycol diphosphite, tetraphenyl tetra (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 Phosphites, bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, 2,2′-methylenebis(4,6-di-tert-butylphenyl)octylphosphite, bis( 2,4-dicumylphenyl)pentaerythritol diphosphite and the like. Among these, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite is preferred.

The organic phosphonite compound preferably has the following general formula:
R ⁵ -P(OR ⁶ )(OR ⁷ )
(wherein 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 is an aryl group having 6 to 30 carbon atoms.)
The compound represented by is mentioned.

Examples of organic phosphonite compounds include tetrakis(2,4-di-iso-propylphenyl)-4,4'-biphenylene diphosphonite, tetrakis(2,4-di-n-butylphenyl)-4,4'-biphenyl diphosphonite, tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylenediphosphonite, tetrakis(2,4-di-tert-butylphenyl)-4,3'-biphenylenediphosphonite night, tetrakis(2,4-di-tert-butylphenyl)-3,3'-biphenylenediphosphonite, tetrakis(2,6-di-iso-propylphenyl)-4,4'-biphenylenediphosphonite, Tetrakis (2,6-di-n-butylphenyl)-4,4'-biphenylene diphosphonite, tetrakis (2,6-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite, tetrakis ( 2,6-di-tert-butylphenyl)-4,3'-biphenylenediphosphonite, tetrakis(2,6-di-tert-butylphenyl)-3,3'-biphenylenediphosphonite, and the like. .

As the sulfur-based stabilizer, any conventionally known sulfur atom-containing compound can be used, and thioethers are particularly preferable. Specific examples include didodecylthiodipropionate, ditetradecylthiodipropionate, dioctadecylthiodipropionate, pentaerythritol tetrakis(3-dodecylthiopropionate), thiobis(N-phenyl-β-naphthylamine ), 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, tetramethylthiuram monosulfide, tetramethylthiuram disulfide, nickel dibutyldithiocarbamate, nickel isopropylxanthate, trilauryltrithiophosphite. Among these, pentaerythritol tetrakis(3-dodecylthiopropionate) is preferred.

Phenolic stabilizers include, for example, pentaerythritol tetrakis (3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate), octadecyl-3-(3,5-di-tert-butyl-4 -hydroxyphenyl)propionate, thiodiethylenebis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), pentaerythritol tetrakis(3-(3,5-di-neopentyl-4-hydroxyphenyl) ) propionate) and the like. Among these, pentaerythritol-letetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl ) propionate is preferred.

One stabilizer may be contained, or two or more stabilizers may be contained in any combination and ratio.

The content of the stabilizer is preferably 0.001 to 2 parts by mass with respect to a total of 100 parts by mass 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 part by mass, it is difficult to expect an improvement in the thermal stability and compatibility of the resin composition, and a decrease in molecular weight and deterioration in color during molding are likely to occur. If it exceeds, the amount becomes excessive, and the generation of silver and the deterioration of the hue tend to occur more easily. The stabilizer content is more preferably 0.01 to 1.5 parts by mass, and still more preferably 0.1 to 1 part by mass.

[Release agent]
The thermoplastic resin composition of the present invention preferably contains a release agent. As the release agent, known release agents that are commonly used for polyester resins can be used. Among them, polyolefin compounds and fatty acid ester compounds are preferable in terms of good alkali resistance, and particularly polyolefin compounds. Compounds are preferred.

Examples of polyolefin compounds include compounds selected from paraffin waxes and polyethylene waxes. Among them, those having a weight average molecular weight of 700 to 10,000, more preferably 900 to 8,000 are preferred.

Examples of fatty acid ester compounds include saturated or unsaturated monovalent or divalent aliphatic carboxylic acid esters, fatty acid esters such as glycerol fatty acid esters, sorbitan fatty acid esters, and partially saponified products thereof. Among them, mono- or di-fatty acid esters composed of fatty acids having 11 to 28 carbon atoms, preferably 17 to 21 carbon atoms, and alcohols 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, melicic acid, tetralyacontanoic acid, montanic acid, adipic acid, and azelaic acid. be done. Fatty acids may also be cycloaliphatic.
Alcohols may include saturated or unsaturated monohydric or polyhydric alcohols. These alcohols may have substituents such as fluorine atoms and aryl groups. Among these, monohydric or polyhydric saturated alcohols having 30 or less carbon atoms are preferred, and saturated monohydric or polyhydric alcohols having 30 or less carbon atoms are more preferred. Here, the term "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. is mentioned.
The above ester compound may contain aliphatic carboxylic acid and/or alcohol as impurities, 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 distearate. rate, stearyl stearate, ethylene glycol montanic acid ester, and the like.

The content of the release agent is preferably 0.1 to 3 parts by mass with respect to 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 mass, still more preferably 0.3 to 2 parts by mass. If the amount is less than 0.1 parts by mass, the surface property tends to be deteriorated due to poor mold release during melt molding. The surface tends to become cloudy.

[Carbon black]
The thermoplastic resin composition of the present invention preferably contains carbon black.
Carbon black is not limited in its type, raw material type, and production method, and any of furnace black, channel black, acetylene black, ketjen black, etc. can be used. Although the number average particle diameter is not particularly limited, it is preferably about 5 to 60 nm.

Carbon black is preferably blended as a masterbatch premixed with a thermoplastic resin, preferably polybutylene terephthalate resin, particularly polybutylene terephthalate resin.

The content of carbon black is preferably 0.1 to 4 parts by mass, more preferably 0.2 to 100 parts by mass in total 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 part 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 contains (A) a polybutylene terephthalate resin, (B) a polystyrene resin or rubber-reinforced polystyrene resin, and (D) a thermoplastic resin other than the resins described above as a compatibilizer, It can be contained within a range that does not impair the effects of the present invention. Specific examples of other thermoplastic resins include polyacetal resins, polyamide resins, polyphenylene oxide resins, polyphenylene sulfide resins, polysulfone resins, polyethersulfone resins, polyetherimide resins, polyetherketone resins, and polyolefin resins. etc.
However, when other resins are contained, the content is preferably 20 parts by mass or less with respect to 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, and particularly preferably 3 parts by mass or less.

In addition, the thermoplastic resin composition of the present invention may contain various additives other than those described above. agents, antistatic agents, antifogging agents, antiblocking agents, plasticizers, dispersants, antibacterial agents, coloring agents other than carbon black, dyes and pigments, and the like.

[Production of thermoplastic resin composition]
The thermoplastic resin composition of the present invention can be produced according to a conventional method for preparing a resin composition. That is, (A) polybutylene terephthalate resin and (B) polystyrene resin or rubber-reinforced polystyrene resin, other resin components added as desired, and various additives are thoroughly mixed together, and then extruded by a single-screw or twin-screw extruder. Melt and knead. The resin composition can also be prepared without premixing the respective components, or premixing only a part of them, feeding them to an extruder using a feeder and melt-kneading them. (C) Carbon fibers are preferably side-fed. Alternatively, a masterbatch of a part thereof may be blended and melt-kneaded. Furthermore, it is also possible to supply 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 to produce various moldings.

The heating temperature for melt-kneading can be appropriately selected from the range of 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 structure in consideration of shear heat generation and the like. In order to suppress decomposition during kneading and subsequent molding, it is desirable to use antioxidants and heat stabilizers.

The thermoplastic resin composition of the present invention is lightweight and preferably has a specific gravity in the range of 1.0 to 1.33. Here, the specific gravity is a value measured according to ISO1183.

[Molded body]
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, hollow molding such as gas assist, molding using heat insulating molds, and rapid heating molds. 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, laminate molding method, press molding method, A blow molding method and the like can be mentioned. Among them, the injection molding method is preferable because the effects of the present invention are remarkable, such as improvement in productivity and surface properties of the resulting molded article.

The resulting molded article has high heat resistance, low warpage, and excellent mechanical strength, so it is suitable for use as electrical and electronic equipment parts, interior and exterior parts for automobiles, and other electrical parts that require these properties strictly. be done. In particular, as interior and exterior parts for automobiles, it can be particularly suitably used for electrical connector parts for automobiles, housings for head-up displays installed in automobiles, housings for engine control units (ECUs), and the like.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention should not be construed as being limited to the following examples.
The components used in the following examples and comparative examples are shown in Table 1 below.

(Examples 1-5, Comparative Examples 1-4)
Among the components shown in Table 1 above, each component excluding carbon fiber is uniformly mixed in a tumbler mixer at a ratio (all parts by mass) shown in Table 2 below, and then a twin-screw extruder (Nippon Steel "TEX30α" manufactured by Tokoro Co., Ltd., L/D = 42), the carbon fiber is supplied from the side feeder, and the resin composition is melted and kneaded under the conditions of a cylinder setting temperature of 260 ° C, a discharge rate of 40 kg / h, and a screw rotation speed of 200 rpm. The material was quenched in a water bath and pelletized using a pelletizer to obtain pellets of the thermoplastic resin composition.

[MVR]
MVR is the melt flow volume MVR per unit time (unit: cm ³ /10 min) of the pellets obtained above under conditions of 265 ° C. and a load of 5 kgf using a melt indexer manufactured by Takara Industries Co., Ltd. Measured. bottom.

[specific gravity]
The specific gravity was measured according to ISO1183.

[Tensile breaking strength, tensile breaking elongation]
After drying the pellets obtained above at 120 ° C. for 5 hours, using an injection molding machine manufactured by Nippon Steel Corporation (clamping force 85 T), under the conditions of a cylinder temperature of 250 ° C. and a mold temperature of 80 ° C., ISO multi-purpose Specimens (4 mm thick) were injection molded.
Based on ISO527, tensile strength at break (unit: MPa) and tensile elongation at break (unit: %) were measured using the above ISO multi-purpose test piece (4 mm thick).
[Maximum flexural strength, flexural modulus]
Using the ISO multi-purpose test piece (4 mm thick), the maximum flexural strength (unit: MPa) and flexural modulus (unit: MPa) were measured at a temperature of 23° C. in accordance with ISO178.
[Charpy impact strength with notch]
Notched Charpy impact strength (unit: kJ/m ² ) was measured at a temperature of 23° C. for a notched test piece obtained by notching the above ISO multipurpose test piece (4 mm thick) according to ISO179.

[Deformation temperature under load and judgment of heat resistance]
Using the above ISO multi-purpose test piece (4 mm thick), the load deflection temperature (unit: ° C.) was measured under the condition of a load of 0.45 MPa in accordance with ISO75-1 and ISO75-2.
Heat resistance was determined according to the following criteria.
○: Deflection temperature under load is 150°C or more △: Deflection temperature under load is 130°C or more and less than 150°C ×: Deflection temperature under load is less than 130°C

[Warpage amount and determination of low warpage]
Using an injection molding machine ("NEX80" manufactured by Nissei Plastic Industry Co., Ltd.), a cylinder temperature of 260 ° C and a mold temperature of 80 ° C are used to mold a circular plate with a diameter of 100 mm and a thickness of 1.6 mm using a side gate mold. The warp amount (unit: mm) of the plate was obtained.
Low warpage was evaluated and determined according to the following criteria.
○: The amount of warp is less than 1 mm △: The amount of warp is 1 mm or more and less than 3 mm ×: The amount of warp is 3 mm or more The results are shown in Table 2 below.

Since the thermoplastic resin composition of the present invention has high heat resistance and excellent low warpage and mechanical strength, it can be used as electrical and electronic equipment parts, interior and exterior parts for automobiles, and other electrical parts where these properties are strictly required. It is particularly suitable for use.

Claims (7)

(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) 50 to 90 masses of polystyrene resin or rubber-reinforced polystyrene resin (excluding syndiotactic polystyrene resin) having a melt viscosity of 80 to 500 Pa·sec at 250°C and 912 sec ^-1 part,
(C) A thermoplastic resin composition characterized by containing 5 to 100 parts by mass of carbon fiber with respect to a total of 100 parts by mass of (A) and (B). 2. The thermoplastic resin composition according to claim 1, further comprising (D) a compatibilizer in an amount of 1 to 30 parts by mass with respect to a total of 100 parts by mass of (A) and (B). 3. The thermoplastic resin composition according to claim 1, wherein (C) the carbon fibers have an average fiber diameter of 10 [mu]m or less. The thermoplastic resin composition according to any one of claims 1 to 3, which has a specific gravity in the range of 1.0 to 1.33. A molded article made of the thermoplastic resin composition according to any one of claims 1 to 4. 6. The molded article according to claim 5, which is an automotive electrical connector part. 6. The molded article according to claim 5, which is a housing for a head-up display or an engine control unit.