JP2022069942A - Thermoplastic resin composition - Google Patents

Abstract

To provide a thermoplastic resin composition that has high resistance to warping and high weld strength, and also has high heat resistance and laser weldability.SOLUTION: A thermoplastic resin composition has (A) a polybutylene terephthalate resin with an inherent viscosity IV of 0.3-0.8 of 15-45 pts.mass and (B) a styrenic polymer of 55-85 pts.mass. Relative to 100 pts.mass of the total of (A) and (B), (C) a glass fiber 10-150 pts.mass is contained. The (B) styrenic polymer is composed of (B-1) a polystyrenic resin with a meltviscosity at 250°C, 912 sec-1 of 70-500 pa s and (B-2) a styrenic elastomer.SELECTED DRAWING: None

Description

The present invention relates to a thermoplastic resin composition, and more particularly to a thermoplastic resin composition having excellent low warpage property and weld strength, and also excellent heat resistance and laser welding property.

Thermoplastic polyester resins typified by polybutylene terephthalate and polyethylene terephthalate are excellent in mechanical strength, chemical resistance, electrical insulation, etc., and therefore are excellent in electrical and electronic equipment parts, interior and exterior parts for automobiles, and other electrical parts and mechanical parts. It is widely used for such purposes.

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

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

Further, in Patent Document 2, (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) Two or more kinds of resins from (d-1) maleic anhydride-modified polystyrene resin, (d-2) rubber-modified polystyrene resin and (d-3) polycarbonate resin 1 to 20% by weight, (E) glass fiber 0 A thermoplastic polyester resin composition containing up to 50% by weight, (F) a halogenated epoxy bromine-based flame retardant of 3 to 20% by weight, and (G) an antimony compound of 1 to 10% by weight is flame-retardant and has high impact resistance. In addition to high strength and low warpage, it is described that it is excellent in heat cycle property, dimensional stability after annealing treatment, and heat resistance rigidity. However, recently, heat resistance and low warpage are required at extremely high levels, and the thermoplastic polyester resin composition described in Patent Document 2 is still insufficient in terms of heat resistance and low warpage.

According to Patent Document 3, the present inventor has made polystyrene resin rich by combining a low molecular weight polyalkylene terephthalate resin and a high molecular weight polystyrene resin with a small amount of polyalkylene terephthalate resin and a large amount of polystyrene resin. Nevertheless, it has been proposed that the resin composition exhibits high heat resistance, which is a characteristic of polyalkylene terephthalate, and is also excellent in low warpage. However, although this resin composition is excellent in the above points, it has been found that there is a problem in weld strength and that the weldability is poor in the case of laser welding. Poor weld strength is prone to cracking, especially when molding large products with multipoint gates.

Japanese Unexamined Patent Publication No. 2006-16559 Japanese Unexamined Patent Publication No. 2007-314619 International release WO2020 / 110011

An object (problem) of the present invention is to provide a thermoplastic resin composition having excellent low warpage and weld strength, excellent heat resistance and laser welding, and excellent mechanical strength and chemical resistance. ..

As a result of diligent studies to solve the above-mentioned problems, the present inventor combines a small amount of a low molecular weight polyalkylene terephthalate resin and a large amount of a polystyrene-based polymer composed of a polystyrene-based resin having a specific melt viscosity and a styrene-based elastomer. As a result, it was found that the above-mentioned problems could be solved, and the present invention was reached.
The present invention relates to the following thermoplastic resin compositions.

1. 1. (C) Glass fiber 10 with respect to (A) 15 to 45 parts by mass of a polybutylene terephthalate resin having an intrinsic viscosity IV of 0.3 to 0.8 and (B) 55 to 85 parts by mass of a styrene polymer, for a total of 100 parts by mass. The (B) styrene-based polymer contains up to 150 parts by mass, and the (B-1) styrene resin and (B-2) styrene have a melt viscosity in the range of 70 to 500 pa · s at 250 ° C. and 912 sec ^-1 . A thermoplastic resin composition comprising a styrene-based elastomer.
2. 2. (B-2) The thermoplastic resin composition according to 1 above, wherein the content of the styrene-based elastomer is 2 to 20 parts by mass with respect to 100 parts by mass in total of (A) and (B).
3. 3. (B-2) The thermoplastic resin composition according to 1 or 2 above, wherein the styrene-based elastomer has a mass average molecular weight of 350,000 to 600,000.
4. The above 1 to 3 in which the mass ratio (B-1) / (B-2) of the contents of the (B-1) polystyrene-based resin and the (B-2) styrene-based elastomer is 3 to 15 is described. Thermoplastic resin composition.

5. The thermoplastic resin composition according to any one of 1 to 4 above, further comprising (D) a polycarbonate resin in an amount of 1 to 30 parts by mass with respect to a total of 100 parts by mass of (A) and (B).
6. (B-2) The styrene-based elastomer comprises at least two polymer blocks P mainly composed of a vinyl aromatic compound and at least one polymer block Q mainly composed of butadiene and / or isoprene, and is a polymer. The thermoplastic resin composition according to any one of 1 to 5 above, which is a block polymer in which block P occupies 20 to 60% by mass, or a hydrogenated block polymer obtained by hydrogenating the block copolymer. ..
7. The thermoplastic resin composition according to any one of 1 to 6 above, which is laser welded.
8. The thermoplastic resin composition according to any one of 1 to 6 above, which is used for an in-vehicle housing component.

In the thermoplastic resin composition of the present invention, (A) the polybutylene terephthalate resin is low, (B) the styrene polymer is rich, but the low molecular weight (A) polybutylene terephthalate resin is the sea of the sea island structure. It becomes a sea of (matrix) or co-continuous structure, (B-1) polystyrene-based resin with high melt viscosity becomes islands, and (B-2) styrene-based elastomer is present due to its thickening effect (B-1). ) Since the islands of the polystyrene-based resin are more aggregated, the weld strength is high, the warp resistance is excellent, the heat resistance is excellent, and the mechanical strength, appearance, and chemical resistance are also excellent. Further, by containing (C) glass fiber, the resin phase of the polybutylene terephthalate resin becomes continuous via the glass fiber, so that it becomes easy to form a matrix (sea), and as a result, low warpage and weld strength are obtained. It is excellent in heat resistance and laser welding. The laser welding method is a method of irradiating a resin molded product containing a heat absorber such as carbon black with a laser, melting the resin skin layer of the molded product with the energy, and adhering it to the skin layer of another member. The adhesion strength between the skin layer and the resin skin layer is similar to the strength of the contact surface between the resin and the resin that has flowed in the molded product. Therefore, the resin composition of the present invention having excellent weld strength is also excellent in laser welding property. Further, when the (D) polycarbonate resin is further contained, the strength and appearance can be further improved.
Therefore, the thermoplastic resin composition of the present invention can be suitably used as parts for various electric and electronic devices, interior / exterior parts for automobiles, housing parts for automobiles, and the like. In addition, the molded product can achieve high welding strength by laser welding.

The thermoplastic resin composition of the present invention comprises (A) 15 to 45 parts by mass of a polybutylene terephthalate resin having an intrinsic viscosity IV of 0.3 to 0.8 and (B) 55 to 85 parts by mass of a styrene polymer, for a total of 100 parts by mass. (C) Contains 10 to 150 parts by mass of glass fiber, and (B) the styrene-based polymer has a melt viscosity in the range of 70 to 500 pa · s at (B-1) 250 ° C. and 912 sec ^-1 . It is characterized by being composed of a polystyrene-based resin and a (B-2) styrene-based elastomer.

Hereinafter, embodiments of the present invention will be described in detail. Although the description described below may be based on embodiments and specific examples, the present invention is not construed as being limited to such embodiments and specific examples.
In addition, in this specification, "-" is used in the meaning which includes the numerical values described before and after it as the lower limit value and the 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 polymer having an intrinsic viscosity (IV) as low as 0.3 to 0.8 dl / g in combination with (B) a styrene polymer, it has excellent weld strength, low warpage, heat resistance, and mechanical strength. The resin composition has excellent chemical resistance. The polybutylene terephthalate resin (A) preferably has high rigidity. The polybutylene terephthalate resin having high rigidity is characterized by having a rigidity of 1500 MPa or more in a flexural modulus according to ISO 178.
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. Further, when the content is higher than 0.8 dl / g, the above-mentioned sea-island structure is difficult to form, the (B-1) polystyrene-based resin tends to form the sea, the weld strength and low warpage property deteriorate, and the fluidity of the resin composition becomes poor. It is poor and the moldability tends to deteriorate. The intrinsic viscosity (IV) is preferably 0.4 dl / g or more, more preferably 0.5 dl / g or more, further 0.55 dl / g or more, and particularly preferably 0.6 dl / g or more, and preferably 0. It is .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 1: 1 (mass ratio) mixed solvent of tetrachloroethane and phenol.

(A) The polybutylene terephthalate resin is a polyester resin having a structure in which a terephthalic acid unit and a 1,4-butanediol unit are ester-bonded. In addition to the polybutylene terephthalate resin (homopolymer), a terephthalic acid unit and 1 , A polybutylene terephthalate copolymer containing other copolymerization components other than 4-butanediol units, and a mixture of a homopolymer and the copolymer.

(A) The polybutylene terephthalate resin may contain a dicarboxylic acid unit other than terephthalic acid, and specific examples of other dicarboxylic acids include isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, and 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) Aromatic dicarboxylic acids such as methane, anthracendicarboxylic acid, 4,4'-diphenylether dicarboxylic acid, alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, 4,4'-dicyclohexyldicarboxylic acid, Examples thereof include 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 the 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 can be mentioned. In addition to the above-mentioned bifunctional monomers, trifunctional monomers such as trimellitic acid, trimesic acid, pyromellitic acid, pentaerythritol, and trimethylolpropane for introducing a branched structure, and fatty acids for adjusting the molecular weight, etc. A small amount of the monofunctional compound can also be used in combination.

As the polybutylene terephthalate resin (A), as described above, a polybutylene terephthalate homopolymer obtained by polycondensing terephthalic acid and 1,4-butanediol is preferable, but the crystallinity of the (A) polybutylene terephthalate resin is also preferable. Polybutylene terephthalate copolymer containing one or more dicarboxylic acids other than the above-mentioned terephthalic acid and / or one or more diols other than the above 1,4-butanediol as a carboxylic acid unit within a range not impairing the above. When the (A) polybutylene terephthalate resin is a polybutylene terephthalate resin modified by copolymerization, specific preferred copolymers thereof include polyalkylene glycols, particularly polytetramethylene glycol. Examples thereof include a polyester ether resin obtained by copolymerizing the above, a dimer acid copolymerized polybutylene terephthalate resin, and an isophthalic acid copolymerized polybutylene terephthalate resin.
In addition, these copolymers have a copolymerization amount of 1 mol% or more and less than 50 mol% in all segments of a 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%, and particularly preferably 5 to 20 mol%. With such a copolymerization ratio, fluidity and toughness tend to be improved, which is preferable.

The polybutylene terephthalate resin (A) preferably has a terminal carboxyl group amount of 0.1 to 30 eq / ton. If it exceeds 30 eq / ton, the hydrolysis resistance and the alkali resistance tend to decrease, and gas tends to be generated during melt molding of the resin composition. The amount of the terminal carboxyl group 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.

The amount of terminal carboxyl groups in the polybutylene terephthalate resin is a value measured by dissolving 0.5 g of the polybutylene 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 the terminal carboxyl group, a method for adjusting the polymerization conditions such as the raw material charging ratio at the time of polymerization, the polymerization temperature, the depressurization method, the method for reacting the terminal blocking agent, and the like, any conventionally known method can be used. Just do it.

(A) The polybutylene terephthalate resin is obtained by melt-polymerizing a dicarboxylic acid component containing terephthalic acid as a main component or an ester derivative thereof and a diol component containing 1,4-butanediol as a main component by a batch method or a continuous method. Can be manufactured. Further, the degree of polymerization (or molecular weight) can be increased to a desired value by producing a low molecular weight polybutylene terecturate resin by melt polymerization and then 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 containing terephthalic acid as a main component and a diol component containing 1,4-butanediol as a main component are continuously melt-polycondensed. Is preferable.

The catalyst used in carrying out the esterification reaction may be a conventionally known one, and examples thereof include titanium compounds, tin compounds, magnesium compounds, calcium compounds and the like. Of these, a titanium compound is particularly suitable. 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) Styrene-based polymer]
The thermoplastic resin composition of the present invention contains (B) a polystyrene-based polymer, and (B) a polystyrene-based polymer. It is composed of (B-1) a polystyrene-based resin having a melt viscosity in the range of 70 to 500 pa · s at 250 ° C. and 912 sec ^-1 , and (B-2) a styrene-based elastomer.

[(B-1) Polystyrene resin]
(B-1) The polystyrene-based resin is a polystyrene-based resin having a melt viscosity in the range of 70 to 500 pa · s at 250 ° C. and 912 sec ^-1 , preferably a polystyrene resin and / or a rubber-reinforced polystyrene resin.

(B-1) The polystyrene-based resin is preferably amorphous. Here, amorphous refers to a characteristic in which a clear melting point and melting peak are not detected when a sample is measured using a differential scanning calorimeter (DSC) or the like. On the contrary, the crystallinity means a property that a crystal structure in which molecules are regularly arranged is likely to be obtained and has a melting point and a melting peak as measured by a differential scanning calorimeter (DSC) or the like. Syndiotactic polystyrene or the like in which benzene rings are regularly arranged alternately with respect to the polymer main chain is crystalline and is preferably excluded as the (B-1) polystyrene-based resin.

The polystyrene resin is a homopolymer of styrene or a copolymer of other aromatic vinyl monomers such as α-methylstyrene, paramethylstyrene, vinyltoluene, vinylxylene and the like in a range of, for example, 50% by mass or less. There may be.

The rubber-reinforced polystyrene resin is preferably a copolymer or blend of 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, still more preferably 5 to 20% by mass. As the rubber reinforced polystyrene resin, high impact polystyrene (HIPS) is particularly preferable.

In the present invention, as the (B-1) polystyrene-based resin, a resin having a melt viscosity of 70 to 500 pa · s at 250 ° C. and 912 sec ^-1 is used. A (B) styrene-based polymer composed of a (B-1) polystyrene-based resin having such a melt viscosity (η _B ) and a (B-2) styrene-based elastomer can be obtained from (A) 15 to 45 parts by mass of a polybutylene terephthalate resin. (B) By blending 55 to 85 parts by mass of the styrene polymer [based on 100 parts by mass of (A) and (B) in total], the polybutylene terephthalate resin (A) becomes dominant in terms of physical properties. As a result, high heat resistance, low warpage and weld strength can be achieved. If the melt viscosity is 70 pa · s or more, the heat resistance can be improved. Further, when the melt viscosity is 500 pa · s or less, excellent production stability and fluidity can be provided.

(B-1) The melt viscosity (η _B ) of the polystyrene-based resin is preferably 80 Pa · sec or more, more preferably 90 Pa · sec or more, still more preferably 100 Pa · sec or more, especially 110 Pa · sec or more, particularly 120 Pa · sec. It is preferably sec or more. The upper limit thereof is preferably 400 Pa · sec or less, more preferably 300 Pa · sec or less, further 200 Pa · sec or less, particularly preferably 180 Pa · sec or less, and particularly preferably 160 Pa · sec or less.
The melt viscosity conforms to ISO 11443 and can be measured by using a capillary reometer and a slit direometer. Specifically, using an orifice with a capillary diameter of 1 mm and a capillary length of 30 mm, the piston melts from the stress when the piston is pushed into a furnace body with an inner diameter of 9.5 mm heated to 250 ° C. at a piston speed of 75 mm / min. The viscosity can be calculated.

[(B-2) Styrene-based elastomer]
(B-2) As the styrene-based elastomer, a block copolymer composed of a polymer block containing a vinyl aromatic compound as a polymerization component and a polymer block containing a conjugated diene as a polymerization component, and a hydrogenated product thereof are preferable.

Examples of the vinyl aromatic compound constituting the polymer block of the vinyl aromatic hydrocarbon include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, pt-butylstyrene, 1,3-dimethylstyrene, and the like. Examples thereof include styrene such as lower alkyl-substituted styrene, vinylnaphthalene and vinylanthracene, or derivatives thereof. These can be used alone or in combination of two or more.

Examples of the conjugated diene constituting the conjugated diene block include butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene and the like.

(B-2) The styrene-based elastomer comprises at least two polymer blocks P mainly composed of vinyl aromatic compounds and at least one polymer block Q mainly composed of butadiene and / or isoprene. , A block copolymer represented by (PQ) n-P (n represents an integer of 1 or more), a block copolymer of triblock or more is preferable, and the polymer block P is A block copolymer occupying 20 to 60% by mass or a hydrogenated block copolymer obtained by hydrogenating the block copolymer is preferable.
In the above, the term "main body" means that it is more than 50% by mass, preferably 50% by mass or more, more preferably 60% by mass or more, further 70% by mass or more, and particularly 80% by mass or more. Is 90% by mass or more.

A block copolymer such as triblock represented by the formula (PQ) n-P has a high molecular weight-matching thickening effect and becomes an island portion in the sea-island structure formed by the obtained resin composition (B). -1) It is preferable because the islands of the polystyrene-based resin are more aggregated and the effect of improving the weld strength is higher. In the case of a PQ-type diblock copolymer, the fluidity is too good and the thickening effect tends to be small, and the effect of improving the weld strength tends to be small.

(B-2) Preferred specific examples of the styrene-based elastomer include styrene-butadiene-styrene block copolymer (SBS), hydrogenated styrene-butadiene-styrene block copolymer (SEBS), and styrene-isoprene-styrene block. Polymers (SIS), hydrogenated styrene-isoprene-styrene block copolymers (SEPS) and the like can be mentioned.

(B-2) A high molecular weight styrene-based elastomer has a high thickening effect, and (B-1) the island portion of the polystyrene-based resin is more likely to aggregate and the effect of improving the weld strength is enhanced, so that it is preferable. When the average molecular weight is in the range of 350,000 to 600,000, the above effect becomes remarkable, which is preferable. The mass average molecular weight is more preferably 360000 or more, more preferably 550000 or less, further 500,000 or less, and particularly 450,000 or less.

As described above, the content of the (A) polybutylene terephthalate resin is 15 to 45 parts by mass based on the total of 100 parts by mass of (A) and (B), and the content of the (B) styrene polymer is 55 to 85 parts by mass. Although it is a part, (A) is preferably 20 to 45 parts by mass, more preferably 25 to 45 parts by mass, further preferably 30 to 45 parts by mass, and (B) preferably 55 to 80 parts by mass. It is preferably 55 to 75 parts by mass, and more preferably 55 to 70 parts by mass.

The content of the (B-2) styrene-based elastomer is preferably 2 to 20 parts by mass with respect to 100 parts by mass in total of (A) and (B). (B-2) When the content of the styrene-based elastomer is in such a range, the weld strength can be further improved. The content is more preferably 3 parts by mass or more, further preferably 4 parts by mass or more, still more preferably 17 parts by mass or less, still more preferably 15 parts by mass or less.

The content of the polystyrene-based resin (B-1) is preferably 35 to 83 parts by mass with respect to 100 parts by mass in total of (A) and (B). (B-1) When the content of the polystyrene-based resin is in such a range, the weld strength and the low warpage property can be further improved. The content is more preferably 40 parts by mass or more, more preferably 80 parts by mass or less, still more preferably 75 parts by mass or less, and particularly preferably 70 parts by mass or less, 65 parts by mass or less, and 60 parts by mass or less.

The mass ratio (B-1) / (B-2) of the contents of the (B-1) polystyrene-based resin and the (B-2) styrene-based elastomer is preferably 3 to 15. By setting such a mass ratio, it is possible to particularly balance rigidity and heat resistance. The mass ratio is more preferably 3.5 or more, and more preferably 13 or less.

[(C) Glass fiber]
The thermoplastic resin composition of the present invention contains (C) glass fiber.
As the glass fiber, if it is usually used for thermoplastic polyester resin, it has an alkali-resistant glass composition containing A glass, E glass, and zirconia components, chopped strant, 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 compounding such as the master batch of. Among them, as the glass fiber used in the present invention, non-alkali glass (E glass) is preferable for the purpose of improving the thermal stability of the thermoplastic resin composition of the present invention.

(C) The glass fiber may have a round cross section in the length direction, and a glass fiber having an irregular shape ratio of 2 to 6 in the cross section in the length direction is also preferable. The irregular shape ratio of the cross section in the length direction assumes a rectangle with the minimum area circumscribing the cross section perpendicular to the length direction of the glass fiber, and the length of the long side of this rectangle is the major axis, and the length of the short side. It is the ratio of the major axis / the minor axis when the minor axis is defined as. By containing glass fibers having a variant ratio of 2 to 6, the glass fibers are oriented to exhibit the function of bridging between the phases of the (A) polybutylene terephthalate resin, and the polybutylene terephthalate resin is a matrix (sea). ), Therefore, the heat resistance is specifically improved, and it is also possible to make it excellent in low warpage and appearance.
Furthermore, when the glass fiber exists in a state of being surrounded by the phase of the (A) polybutylene terephthalate resin, the bridging effect between the (A) polybutylene terephthalate resin phase by the glass fiber is higher. In addition, since the bulky glass fiber acts as a bulking agent for the (A) polybutylene terephthalate resin, the heat resistance is likely to be further improved.

In the case of a glass fiber having a modified cross section, the irregular shape ratio is more preferably 2.5 or more, further preferably 3 or more, still more preferably 5.5 or less, still more preferably 5 or less. It is particularly preferable that the shape of the cross section in the length direction is substantially rectangular.
The cross-sectional area of the glass fiber in the length direction is preferably 180 μm ² or more and 300 μm ² or less, and such a cross-sectional area makes it easy for the polybutylene terephthalate resin to form a matrix, resulting in improved heat resistance. easy. The cross-sectional area is more preferably 180 μm ² or more and 250 μm ² or less, and further preferably 180 μm ² or more and 200 μm ² or less.
The thickness of the glass fiber is not particularly limited, but it is preferable that the minor axis is about 2 to 20 μm and the major axis is about 5 to 50 μm.

(C) The glass fiber may be treated with a sizing agent or a surface treating agent. Further, at the time of producing the resin composition of the present invention, a sizing agent or a surface treating agent may be added separately from the untreated glass fiber 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 the surface treatment agent include aminosilane compounds such as γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and γ- (2-aminoethyl) aminopropyltrimethoxysilane, vinyltrichlorosilane, and methylvinyldi. Chlorosilane compounds such as chlorosilane, alkoxysilane compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, γ-methacryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxy Examples thereof include epoxysilane compounds such as silane and 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 (adhesion amount) used thereof is usually 10% by mass or less, preferably 0.05 to 0, based on the mass of (C) glass fiber. It is 5% by mass. By setting the adhesion amount to 10% by mass or less, a necessary and sufficient effect can be obtained.

The glass fiber (C) may be used in combination of two or more depending on the required properties, and the content thereof is based on 100 parts by mass of the total of (A) polybutylene terephthalate resin and (B) styrene polymer. It is 10 to 150 parts by mass, preferably 20 parts by mass or more, more preferably 30 parts by mass or more, particularly preferably 40 parts by mass or more, preferably 120 parts by mass or less, and more preferably 100 parts by mass or less. 80 parts by mass or less, particularly preferably 60 parts by mass or less. By containing it in such a range, high heat resistance can be achieved, and the effect of reducing the strength and shrinkage of the obtained molded product can be enhanced.

The resin composition of the present invention exists in a state in which (C) glass fibers are surrounded by a phase of (A) polybutylene terephthalate resin in the cross-sectional structure of the molded body of the resin composition observed with an electron microscope. Is preferable. Further, it is preferable that the (A) polybutylene terephthalate resin forms a co-continuous phase with the sea (matrix) having a sea-island structure or the (B-1) polystyrene-based resin. By having such a morphology structure, the heat resistance is specifically improved, the warp property is excellent, and the appearance is likely to be excellent.

The thermoplastic resin composition of the present invention preferably contains carbon fibers or other plate-shaped, granular or amorphous fillers in addition to the above-mentioned (C) glass fibers. The plate-shaped inorganic filler exhibits a function of reducing anisotropy and warpage, and examples thereof include talc, glass flakes, mica, mica, kaolin, and metal foil. Among the plate-shaped inorganic fillers, glass flakes are preferable.
Examples of other granular or amorphous 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 preferable, and talc is particularly preferable.

The content of the other inorganic filler is preferably 0.1 to 30 parts by mass with respect to 100 parts by mass in total of the (A) polybutylene terephthalate resin and (B) styrene polymer. 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 or less.

[(D) Polycarbonate resin]
The resin composition of the present invention preferably further contains (D) a polycarbonate resin. By containing (D) a polycarbonate resin, the compatibility between the (A) polybutylene terephthalate resin and the (B-1) polystyrene resin is promoted, so that the polybutylene terephthalate resin is dispersed in the (A) polybutylene terephthalate resin phase (B). -1) By reducing the dispersed particle size of the polystyrene-based resin and increasing the interfacial strength, the mechanical strength can be further improved and an excellent appearance can be easily obtained.

The polycarbonate resin is a optionally branched thermoplastic polymer or copolymer obtained by reacting a dihydroxy compound or a small amount of a polyhydroxy compound with phosgene or a carbonic acid diester. The method for producing the polycarbonate resin is not particularly limited, and those produced by a conventionally known phosgene method (interfacial polymerization method) or melting method (transesterification method) can be used.

The raw material dihydroxy compound is substantially free of bromine atoms, and aromatic dihydroxy compounds are preferable. Specifically, 2,2-bis (4-hydroxyphenyl) propane (ie, bisphenol A), tetramethylbisphenol A, bis (4-hydroxyphenyl) -p-diisopropylbenzene, hydroquinone, resorcinol, 4,4- Examples thereof include dihydroxydiphenyl, and preferably bisphenol A. Further, a compound in which one or more tetraalkylphosphonium sulfonates are bonded to the above aromatic dihydroxy compound can also be used.

Among the above-mentioned polycarbonate resins, the aromatic polycarbonate resin derived from 2,2-bis (4-hydroxyphenyl) propane (that is, bisphenol A) or 2,2-bis (4-hydroxyphenyl) propane is used as the polycarbonate resin. Aromatic polycarbonate copolymers derived from and other aromatic dihydroxy compounds are preferred. Further, it may be a copolymer mainly composed of an aromatic polycarbonate resin, such as a polymer having a siloxane structure or a copolymer with an oligomer. Further, two or more of the above-mentioned polycarbonate resins may be mixed and used.

To adjust the molecular weight of the polycarbonate resin, a monovalent aromatic hydroxy compound may be used, for example, m- and p-methylphenol, m- and p-propylphenol, p-tert-butylphenol, p-long chain. Examples thereof include alkyl-substituted phenols.

The viscosity average molecular weight (Mv) of the polycarbonate resin is preferably 15,000 or more, more preferably 20,000 or more, still more preferably 23,000 or more, particularly preferably 25,000 or more, and particularly most preferably 28,000 or more. preferable. If a resin composition having a viscosity average molecular weight lower than 15,000 is used, the obtained resin composition tends to have low mechanical strength such as impact resistance. The 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 be deteriorated and the moldability may be deteriorated.

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

The method for producing the polycarbonate resin is not particularly limited, and a polycarbonate resin produced by any of a phosgene method (interfacial polymerization method) and a melting method (transesterification method) can be used. Further, a polycarbonate resin produced by a melting method and subjected to post-treatment for adjusting the amount of OH groups at the ends is also preferable.

The content of the polycarbonate resin (D) is preferably 1 to 30 parts by mass, more preferably 3 parts by mass or more, based on 100 parts by mass of the total of (A) polybutylene terephthalate resin and (B) styrene-based polymer. More preferably 5 parts by mass or more, particularly preferably 8 parts by mass or more, particularly preferably 10 parts by mass or more, more preferably 25 parts by mass or less, still more preferably 20 parts by mass or less, and particularly preferably 17 parts by mass or less. It is 15 parts by mass or less.

[Stabilizer]
It is preferable that the thermoplastic resin composition of the present invention contains a stabilizer because it has an effect of improving thermal stability and preventing deterioration of mechanical strength, transparency and hue. As the stabilizer, a phosphorus-based stabilizer, a sulfur-based stabilizer and a phenol-based stabilizer are preferable.

Examples of the phosphorus-based stabilizer include phosphoric acid, phosphoric acid, phosphite, trivalent phosphoric acid ester (phosphonite), pentavalent phosphoric acid ester (phosphate), and the like, among which phosphite is used. , Phosphoronite, phosphate are preferred.

The organic phosphate compound is preferably given 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, a long-chain alkyl acid phosphate compound in which R ¹ has 8 to 30 carbon atoms can be mentioned. Specific examples of the alkyl group having 8 to 30 carbon atoms include an octyl group, a 2-ethylhexyl group, an isooctyl group, a nonyl group, an isononyl group, a decyl group, an isodecyl group, a dodecyl group, a tridecyl group, an isotridecyl group and a tetradecyl group. Examples thereof include a hexadecyl group, an octadecyl group, an eicosyl group, and a 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. Examples thereof include phosphate, dioctyl acid phosphate, dilauryl acid phosphate, distealyl acid phosphate, diphenyl acid phosphate, bisnonylphenyl acid phosphate and the like. Among these, octadecyl acid phosphate is preferable, and this product is commercially available under the trade name "ADEKA STAB AX-71" of ADEKA.

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

Examples of the organic phosphite compound include triphenylphosphite, tris (nonylphenyl) phosphite, dilaurylhydrogenphosphite, triethylphosphite, tridecylphosphite, tris (2-ethylhexyl) phosphite, and tris (tridecyl). ) Phenylphosphite, tristearylphosphite, diphenylmonodecylphosphite, monophenyldidecylphosphite, diphenylmono (tridecyl) phosphite, tetraphenyldipropylene glycol diphosphite, tetraphenyltetra (tridecyl) pentaerythritol tetraphosphite , Hydrogenated Bisphenol A Phenol Phenylphosphite Polymer, Diphenylhydrogenphosphite, 4,4'-butylidene-bis (3-methyl-6-tert-butylphenyldi (tridecyl) phosphite), Tetra (tridecyl) 4,4 '-Isopropyridene 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) pentaerythritoldi Phosphite, 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 preferable.

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

Examples of the organic phosphonite compound include tetrakis (2,4-di-iso-propylphenyl) -4,4'-biphenylenediphosphonite and tetrakis (2,4-di-n-butylphenyl) -4,4'-bipheni. Range phosphonite, tetrakis (2,4-di-tert-butylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,4-di-tert-butylphenyl) -4,3'-biphenylenediphospho Nite, 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'-biphenylenediphosphonite, tetrakis (2,6-di-tert-butylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,6-di-n-butylphenyl) -4,4'-biphenylenediphosphonite 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 among them, thioethers are preferable. Specifically, for example, didodecylthiodipropionate, ditetradecylthiodipropionate, dioctadecylthiodipropionate, pentaerythritol tetrakis (3-dodecylthiopropionate), thiobis (N-phenyl-β-naphthylamine). ), 2-Mercaptobenzothiazole, 2-Mercaptobenzimidazole, Tetramethylthium monosulfide, Tetramethylthiuram disulfide, Nickeldibutyldithiocarbamate, Nickelisopropylxantate, Trilauryltrithiophosphite. Among these, pentaerythritol tetrakis (3-dodecylthiopropionate) is preferable.

Examples of the phenolic stabilizer include pentaerythritol tetrakis (3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate) and 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 tetrakis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate) and octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) ) Propionate is preferred.

As the stabilizer, one type 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 mass with respect to 100 parts by mass of the total of (A) polybutylene terephthalate resin and (B) styrene polymer. If the content of the stabilizer is less than 0.001 part by mass, it is difficult to expect improvement in thermal stability and compatibility of the resin composition, and a decrease in molecular weight and deterioration of hue during molding are likely to occur, and 2 parts by mass is used. If it exceeds the amount, the amount becomes excessive and the generation of silver and the deterioration of hue tend to occur more easily. The content of the stabilizer is more preferably 0.01 to 1.5 parts by mass, still more preferably 0.1 to 1 part by mass.

[Release agent]
The thermoplastic resin composition of the present invention preferably contains a mold release agent. As the release agent, known release agents usually used for polyester resins can be used, but among them, polyolefin-based compounds and fatty acid ester-based compounds are preferable, and polyolefin-based compounds are particularly preferable, because they have good alkali resistance. 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 10000, more preferably 900 to 8000 are preferable.

Examples of the fatty acid ester-based compound include saturated or unsaturated monovalent or divalent aliphatic carboxylic acid esters, glycerin fatty acid esters, sorbitan fatty acid esters and other fatty acid esters, and partially saponified products thereof. Among them, mono or difatty acid esters composed of fatty acids having 11 to 28 carbon atoms, preferably 17 to 21 carbon atoms and alcohols are preferable.

Examples of fatty acids include palmitic acid, stearic acid, caproic acid, caproic acid, lauric acid, araquinic acid, behenic acid, lignoceric acid, cellotic acid, melicic acid, tetrariacontanic acid, montanic acid, adipic acid, azelaic acid and the like. Will be. Further, the fatty acid may be an alicyclic type.
Examples of the alcohol 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 preferable, and aliphatic saturated monohydric alcohols or polyhydric alcohols having 30 or less carbon atoms are more preferable. Here, the aliphatic term also contains an alicyclic compound.
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.
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 the fatty acid ester compound include glycerin monostearate, glycerin monobehenate, glycerin dibehenate, glycerin-12-hydroxymonostearate, sorbitan monobehenate, pentaerythritol monostearate, and pentaeristoldi. Examples thereof include stearate, stearyl stearate, and ethylene glycol montanic acid ester.

The content of the release agent is preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the total of (A) polybutylene terephthalate resin and (B) styrene polymer, but 0.2 to 2. It is more preferably 5 parts by mass, still more preferably 0.3 to 2 parts by mass. If it is less than 0.1 part by mass, the surface property is likely to be deteriorated due to poor mold release during melt molding, while if it is more than 3 parts by mass, the kneading workability of the resin composition is likely to be deteriorated, and the molded product is formed. The surface tends to be cloudy.

[Carbon black]
The thermoplastic resin composition of the present invention preferably contains carbon black.
The type, raw material type, and manufacturing method of carbon black are not limited, and any of furnace black, channel black, acetylene black, ketjen black, and the like can be used. The number average particle size is not particularly limited, but is preferably about 5 to 60 nm.

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

The content of carbon black is preferably 0.1 to 4 parts by mass, more preferably 0.2 to 3 parts by mass, based on 100 parts by mass of the total of (A) polybutylene terephthalate resin and (B) styrene polymer. be. If it is 0.1 part by mass or more, the effect of obtaining a desired color is enhanced, and the effect of improving weather resistance can be expected. If it is 4 parts by mass or less, it can be expected to suppress deterioration of mechanical properties.

[Other ingredients]
The thermoplastic resin composition of the present invention uses a thermoplastic resin other than the above-mentioned (A) polybutylene terephthalate resin, (B) styrene polymer, and (D) polycarbonate resin as long as the effect of the present invention is not impaired. Can be contained in. Specific examples of other thermoplastic resins include polyacetal resin, polyamide resin, polyphenylene oxide resin, polyphenylene sulfide resin, polysulfone resin, polyether sulfone resin, polyetherimide resin, polyether ketone resin, and polyolefin resin. And so on.
However, when other resins are contained, the content is preferably 20 parts by mass or less, preferably 10 parts by mass or less, based on 100 parts by mass of the total of (A) polybutylene terephthalate resin and (B) styrene polymer. Is more preferable, and more preferably 5 parts by mass or less, particularly preferably 3 parts by mass or less.

Further, 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, antistatic agents, and ultraviolet absorption. Examples thereof include agents, antistatic agents, antifogging agents, antiblocking agents, plasticizers, dispersants, antibacterial agents, colorants, dyes and pigments.

[Manufacturing 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) styrene-based polymer, other resin components added as desired, and various additives are mixed well together and then melt-kneaded by a uniaxial or twin-screw extruder. Further, it is also possible to prepare a resin composition without mixing each component in advance or by mixing only a part thereof in advance and supplying it to an extruder using a feeder to melt-knead it. Further, a masterbatch of a part thereof may be blended and melt-kneaded. Further, it is also possible to supply a mixture in which each component is mixed in advance to a molding machine such as an injection molding machine as it is without melt-kneading to manufacture various molded bodies.

The heating temperature for melt-kneading can be appropriately selected 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 a poor appearance. Therefore, it is desirable to select a screw configuration in consideration of shear heat generation and the like. It is desirable to use an antioxidant or a heat stabilizer in order to suppress decomposition during kneading and molding in the subsequent process.

[Molded product]
The method for producing a molded product using the thermoplastic resin composition of the present invention is not particularly limited, and any molding method generally used for the thermoplastic resin composition can be arbitrarily adopted. For example, an injection molding method, an ultra-high speed injection molding method, an injection compression molding method, a two-color molding method, a hollow molding method such as gas assist, a molding method using a heat insulating mold, and a rapid heating mold were used. Molding method, foam molding (including supercritical fluid), insert molding, IMC (in-mold coating molding) molding method, extrusion molding method, sheet molding method, thermal molding method, rotary molding method, laminated molding method, press molding method, 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 good productivity and surface properties of the obtained molded body.

The obtained molded product has excellent low warpage and weld strength, excellent heat resistance and laser weldability, and excellent mechanical strength and chemical resistance. Therefore, electrical and electronic equipment parts whose characteristics are strictly required. It is suitably used as interior / exterior parts for automobiles and other electrical parts. Electrical and electronic equipment parts include IH cooker housing parts, button cases, grill handles, coil peripheral members, rice cooker protection frames, relay cases, smart meter housings, industrial breaker housings, inverter cases, and mobile phone housings. Specific examples thereof include a body, a housing for warm equipment, a separator for a battery, a case for a battery, a tray for transporting electronic parts, a tray for transporting a battery, a charging facility for an automobile, and the like.
For interior and exterior parts for automobiles, in-vehicle housing parts, in-vehicle battery cases, in-vehicle battery covers, in-vehicle battery separators, various motor cases, sensor cases, camera cases, holder parts, air conditioner wind direction control plates, door mirror stays. It can be particularly preferably used for a housing of a head-up display built in an automobile, a housing for an engine control unit (ECU), and a connector component for electrical components of an automobile.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not construed as being limited to the following examples.

(Examples 1 to 6, Comparative Examples 1 to 4)
The components used are as shown in Table 1 below.

Of the components shown in Table 1 above, the components other than (C) glass fiber are uniformly mixed with a tumbler mixer at the ratio (all by mass) shown in Table 2 below, and then a twin-screw extruder (Japan). Using "TEX30α" manufactured by Japan Steel Works, L / D = 42), (C) glass fiber is charged using a side feeder, cylinder set temperature 260 ° C, discharge rate 40 kg / h, screw rotation speed 200 rpm. The resin composition melt-kneaded under the above conditions was rapidly cooled in a water tank and pelletized using a pelletizer to obtain pellets of the thermoplastic resin composition.

[Tension breaking strength, tensile breaking elongation rate]
After the pellets obtained above are dried at 120 ° C. for 5 hours, ISO multipurpose is used under the conditions of a cylinder temperature of 250 ° C. and a mold temperature of 80 ° C. using an injection molding machine (mold clamping force 85T) manufactured by Japan Steel Works. A test piece (4 mm thick) was injection molded.
In accordance with ISO527, the tensile breaking strength (unit: MPa) and the tensile breaking elongation (unit:%) were measured using the ISO multipurpose test piece (4 mm thickness).
[Maximum bending strength, flexural modulus]
In accordance with ISO178, the maximum bending strength (unit: MPa) and flexural modulus (unit: MPa) were measured at a temperature of 23 ° C. using the above ISO multipurpose test piece (thickness of 4 mm).
[Charpy impact strength with notch]
In accordance with ISO179, the notched Charpy impact strength (unit: kJ / m ² ) of the notched test piece obtained by notching the ISO multipurpose test piece (4 mm thickness) was measured at a temperature of 23 ° C.

[Weld strength and weld strength judgment]
After the pellets obtained above are dried at 100 ° C. for 5 hours, ISO is used under the conditions of a cylinder temperature of 250 ° C. and a mold temperature of 80 ° C. using an injection molding machine (mold clamping force 85T) manufactured by Japan Steel Works, Ltd. A multipurpose test piece (4 mm thick) was molded. The mold used for this molding is provided with gates at both ends of the above-mentioned test piece so that a weld is formed in the center of the test piece.
Using the above-mentioned ISO multipurpose test piece (4 mm thick) in which a weld is formed in the center of the test piece, a tensile test is performed at a tensile speed of 5 mm / min with reference to ISO527, and the weld strength (unit: MPa) is based on the tensile breaking strength. Was evaluated.
Weld strength was determined according to the following criteria.
⊚: Weld strength is 25 MPa or more 〇: Weld strength is less than 25 MPa 23 MPa or more ×: Weld strength is less than 23 MPa

[Degree of deflection temperature under load and heat resistance]
Using the above ISO multipurpose test piece (thickness 4 mm), the deflection temperature under load was measured under the condition of load 1.80 MPa in accordance with ISO75-1 and ISO75-2.
The heat resistance was judged according to the following criteria.
⊚: Deflection temperature under load is 150 ° C or higher 〇: Deflection temperature under load is less than 150 ° C 140 ° C or higher ×: Deflection temperature under load is less than 140 ° C

[Warp amount and warp property judgment]
With an injection molding machine (“NEX80” manufactured by Nissei Resin Industry Co., Ltd.), a disk with a diameter of 100 mm and a thickness of 1.6 mm is used as a side gate metal under the conditions of a cylinder temperature of 260 ° C., a mold temperature of 80 ° C., and an injection time of 0.5 sec. It was molded by a mold, and the amount of warpage (unit: mm) of the disk was determined.
Warpage was evaluated and judged according to the following criteria.
◯: Warpage amount is less than 1 mm ×: Warpage amount is 1 mm or more The results are shown in Table 2 below.

The thermoplastic resin composition of the present invention has excellent low warpage and weld strength, excellent heat resistance and laser welding, and is also excellent in mechanical strength, chemical resistance, and flame retardancy. It can be particularly preferably used as electrical and electronic equipment parts, interior / exterior parts for automobiles, and other electrical parts that are strictly required, and can also be effectively used for manufacturing parts by laser welding.

Claims (8)

(C) Glass fiber 10 with respect to (A) 15 to 45 parts by mass of a polybutylene terephthalate resin having an intrinsic viscosity IV of 0.3 to 0.8 and (B) 55 to 85 parts by mass of a styrene polymer, for a total of 100 parts by mass. The (B) styrene-based polymer contains up to 150 parts by mass, and the (B-1) styrene resin and (B-2) styrene have a melt viscosity in the range of 70 to 500 pa · s at 250 ° C. and 912 sec ^-1 . A thermoplastic resin composition comprising a styrene-based elastomer. (B-2) The thermoplastic resin composition according to claim 1, wherein the content of the styrene-based elastomer is 2 to 20 parts by mass with respect to 100 parts by mass in total of (A) and (B). (B-2) The thermoplastic resin composition according to claim 1 or 2, wherein the styrene-based elastomer has a mass average molecular weight of 350,000 to 600,000. The invention according to any one of claims 1 to 3, wherein the mass ratio (B-1) / (B-2) of the contents of the (B-1) polystyrene resin and the (B-2) styrene elastomer is 3 to 15. Thermoplastic resin composition. The thermoplastic resin composition according to any one of claims 1 to 4, further comprising (D) a polycarbonate resin in an amount of 1 to 30 parts by mass with respect to a total of 100 parts by mass of (A) and (B). (B-2) The styrene-based elastomer comprises at least two polymer blocks P mainly composed of a vinyl aromatic compound and at least one polymer block Q mainly composed of butadiene and / or isoprene, and is a polymer. The thermoplastic resin composition according to any one of claims 1 to 5, which is a block polymer in which the block P occupies 20 to 60% by mass, or a hydrogenated block polymer obtained by hydrogenating the block copolymer. thing. The thermoplastic resin composition according to any one of claims 1 to 6, which is laser welding. The thermoplastic resin composition according to any one of claims 1 to 6, which is for an in-vehicle housing component.