Resin composition and molded article

Abstract

Provided are a resin composition excellent in heat shock resistance, and a molded article using the same.　Provided is a resin composition containing (A) a polybutylene terephthalate resin, (B) a carbodiimide compound, (C) an elastomer, and (D) a fibrous inorganic filler, wherein the carbodiimide compound (B) contains (b1) a cyclic carbodiimide compound and (b2) an aromatic carbodiimide compound, the total content of the cyclic carbodiimide compound (b1) and the aromatic carbodiimide compound (b2) is 0.6 to 2.0 parts by mass relative to 100 parts by mass of the polybutylene terephthalate resin (A), and the mass ratio [(b1) / (b2)] of the cyclic carbodiimide compound (b1) to the aromatic carbodiimide compound (b2) is 0.2 to 1.6.

Description

Resin composition and molded article

[0001] This disclosure relates to resin compositions and molded articles.

[0002] Polybutylene terephthalate (PBT) resin has excellent mechanical, electrical, and moldability properties and is used in a wide range of applications, including automotive parts and electrical / electronic components. In particular, in the automotive sector, it is used as a housing material for sensors and connectors used in electrical control, actuators, and ECUs. Since automotive parts are used in environments with large temperature fluctuations, composite molded products of metal and resin (insert molded products) are prone to cracking due to strain caused by the difference in linear expansion between the metal and the resin. To prevent cracking, it has been proposed to improve the toughness of the resin by adding various additives and elastomers.

[0003] Patent Document 1 describes a composition mainly composed of polybutylene terephthalate resin having a terminal carboxyl group content of 30 meq / kg or less, combined with a specific amount of carbodiimide compound, fibrous filler, and elastomer, which exhibits excellent heat shock resistance and hydrolysis resistance without a significant decrease in mechanical properties. Patent Document 2 describes a polybutylene terephthalate resin composition prepared by blending polybutylene terephthalate resin with benzyl acrylate halogenated compound, antimony oxide compound, carbodiimide compound, and glass fibers as a filler, thereby providing a polybutylene terephthalate resin composition with excellent heat shock resistance, flame retardancy, and hydrolysis resistance.

[0004] International Publication No. 2009 / 150831, International Publication No. 2011 / 058992

[0005] The object of this disclosure is to provide a resin composition with excellent heat shock resistance and a molded article using the same.

[0006] This disclosure encompasses the following embodiments: A resin composition comprising (A) a polybutylene terephthalate resin, (B) a carbodiimide compound, (C) an elastomer, and (D) a fibrous inorganic filler, wherein the (B) carbodiimide compound comprises (b1) a cyclic carbodiimide compound and (b2) an aromatic carbodiimide compound, the total content of the (b1) cyclic carbodiimide compound and the (b2) aromatic carbodiimide compound is 0.6 to 2.0 parts by mass per 100 parts by mass of the (A) polybutylene terephthalate resin, and the mass ratio [(b1) / (b2)] of the (b1) cyclic carbodiimide compound to the (b2) aromatic carbodiimide compound is 0.2 to 1.6.

[0007] According to this disclosure, it is possible to provide a resin composition with excellent heat shock resistance and a molded article using the same.

[0008] This figure shows the shape and dimensions of the test specimens used in the thermal shock resistance test of the example.

[0009] One embodiment of this disclosure will be described in detail below, but the scope of this disclosure is not limited to the embodiment described herein, and various modifications can be made without departing from the spirit of this disclosure. Each embodiment disclosed herein can be combined with any other features disclosed herein. Furthermore, if multiple upper and lower limits are given for a particular parameter, any upper and lower limit can be combined to form a suitable numerical range. Also, the lower and / or upper limits of the numerical ranges described herein may be replaced with numerical values ​​within that range, as shown in the examples. If multiple numerical ranges are given for multiple parameters, any numerical range can be adopted for each parameter and combined as desired. The expression "X to Y" indicating a numerical range means "X or greater and Y or less". If a particular description given for one embodiment also applies to other embodiments, that description may be omitted in the other embodiments.

[0010] <Resin Composition> The resin composition according to this embodiment is a resin composition comprising (A) a polybutylene terephthalate resin, (B) a carbodiimide compound, (C) an elastomer, and (D) a fibrous inorganic filler, wherein the (B) carbodiimide compound comprises (b1) a cyclic carbodiimide compound and (b2) an aromatic carbodiimide compound, the total content of the (b1) cyclic carbodiimide compound and the (b2) aromatic carbodiimide compound is 0.6 to 2.0 parts by mass per 100 parts by mass of the (A) polybutylene terephthalate resin, and the mass ratio [(b1) / (b2)] of the (b1) cyclic carbodiimide compound to the (b2) aromatic carbodiimide compound is 0.2 to 1.6.

[0011] Conventionally, as described in Patent Documents 1 and 2, it is known that carbodiimide compounds are added to resin compositions mainly composed of polybutylene terephthalate resin to improve heat shock resistance and hydrolysis resistance. The carbodiimide compounds added to resin compositions mainly composed of polybutylene terephthalate resin were mainly aliphatic carbodiimide compounds, alicyclic carbodiimide compounds, and aromatic carbodiimide compounds. When these carbodiimide compounds are added to polymers and melt-kneaded, or when the polymers are remelted and processed, isocyanate gases, which are known to be highly irritating and sensitizing substances, are generated, requiring measures to improve the working environment, such as exhaust equipment. As carbodiimides with a structure that does not release isocyanate compounds, cyclic carbodiimide compounds having a carbodiimide ring with one carbodiimide group in one ring are also known, but cyclic carbodiimide compounds are particularly affected by the increase in viscosity due to crosslinking reactions with polybutylene terephthalate, and the moldability of the resin composition deteriorates significantly. The inventors have diligently conducted research and have found that by using aromatic carbodiimide compounds and cyclic carbodiimides in specific ratios and blending them with polybutylene terephthalate resin in a specific total amount, it is possible to provide a resin composition and molded articles using the same that exhibit superior heat shock resistance while suppressing viscosity increase compared to blending aromatic carbodiimide compounds or cyclic carbodiimides alone. This led to the completion of this disclosure. Although the reason for this unique effect has not been specified, it is presumed that the reason for the improved heat shock resistance is that aromatic carbodiimide compounds and cyclic carbodiimides have different reactivity with the end groups of polybutylene terephthalate and different adhesion to fillers, which mitigates local stress that may occur within the molded articles obtained from the resin composition. Furthermore, it is presumed that the reason the increase in viscosity can be suppressed is that by using aromatic carbodiimide compounds and cyclic carbodiimides in combination, the amount of cyclic carbodiimide compounds used can be reduced, thereby suppressing the effects of the crosslinking reaction between the cyclic carbodiimide compounds and polybutylene terephthalate.

[0012] [(A) Polybutylene terephthalate resin] The resin composition according to this embodiment includes (A) polybutylene terephthalate resin. In this specification, "(A) polybutylene terephthalate resin (hereinafter sometimes referred to as PBT resin)" means at least terephthalic acid or its ester-forming derivative (C １－６ This refers to a polybutylene terephthalate resin obtained by polycondensation of a dicarboxylic acid component (such as alkyl esters or acid halides) and a glycol component (such as alkylene glycol (1,4-butanediol) having at least four carbon atoms or its ester-forming derivative (such as acetylated compounds)). In this embodiment, (A) the polybutylene terephthalate resin is not limited to a homopolybutylene terephthalate resin, but may also be a copolymer containing 60 mol% or more of butylene terephthalate units.

[0013] (A) The amount of terminal carboxyl groups in the polybutylene terephthalate resin is not particularly limited as long as it does not hinder the purpose of this disclosure, but is preferably 30 meq / kg or less, and more preferably 25 meq / kg or less.

[0014] (A) The intrinsic viscosity of the polybutylene terephthalate resin is not particularly limited as long as it does not hinder the purpose of this disclosure, but is preferably 0.60 dL / g or more and 1.5 dL / g or less, and more preferably 0.65 dL / g or more and 1.2 dL / g or less. When a polybutylene terephthalate resin with an intrinsic viscosity in this range is used, the resulting polybutylene terephthalate resin composition will have particularly good moldability. Furthermore, the intrinsic viscosity can be adjusted by blending polybutylene terephthalate resins having different intrinsic viscosities. For example, a polybutylene terephthalate resin with an intrinsic viscosity of 0.9 dL / g can be prepared by blending a polybutylene terephthalate resin with an intrinsic viscosity of 1.0 dL / g and a polybutylene terephthalate resin with an intrinsic viscosity of 0.7 dL / g. The intrinsic viscosity of the polybutylene terephthalate resin can be measured, for example, in o-chlorophenol at a temperature of 35°C.

[0015] (A) In the preparation of polybutylene terephthalate resin, when using an aromatic dicarboxylic acid other than terephthalic acid or its ester-forming derivative as a comonomer component, for example, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-dicarboxydiphenyl ether, etc. ８－１４ Aromatic dicarboxylic acids; such as succinic acid, adipic acid, azelaic acid, sebacic acid, etc. ４－１６ C alkanedicarboxylic acids; cyclohexanedicarboxylic acids, etc. ５－１０ Cycloalkanedicarboxylic acids; ester-forming derivatives of these dicarboxylic acid components (C １－６ Alkyl ester derivatives and acid halides (such as those mentioned above) can be used. These dicarboxylic acid components can be used individually or in combination of two or more.

[0016] Among these dicarboxylic acid components, C such as isophthalic acid ８－１２ Aromatic dicarboxylic acids, and C such as adipic acid, azelaic acid, and sebacic acid. ６－１２ Alkane dicarboxylic acids are more preferred.

[0017] (A) In the preparation of polybutylene terephthalate resin, when a glycol component other than 1,4-butanediol is used as the comonomer component, for example, C2-10 alkylene glycols such as ethylene glycol, propylene glycol, trimethylene glycol, 1,3-butylene glycol, hexamethylene glycol, neopentyl glycol, and 1,3-octanediol; polyoxyalkylene glycols such as diethylene glycol, triethylene glycol, and dipropylene glycol; alicyclic diols such as cyclohexanedimethanol and hydrogenated bisphenol A; aromatic diols such as bisphenol A and 4,4'-dihydroxybiphenyl; C2-4 alkylene oxide adducts of bisphenol A, such as a 2-mol ethylene oxide adduct of bisphenol A and a 3-mol propylene oxide adduct of bisphenol A; or ester-forming derivatives (acetylated products, etc.) of these glycols can be used. These glycol components can be used alone or in combination of two or more.

[0018] Among these glycol components, C2-6 alkylene glycols such as ethylene glycol and trimethylene glycol, polyoxyalkylene glycols such as diethylene glycol, or alicyclic diols such as cyclohexanedimethanol are more preferred.

[0019] As comonomer components that can be used in addition to the dicarboxylic acid component and the glycol component, for example, aromatic hydroxycarboxylic acids such as 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, and 4-carboxy-4'-hydroxybiphenyl; aliphatic hydroxycarboxylic acids such as glycolic acid and hydroxycaproic acid; C ３－１２ lactones such as propiolactone, butyrolactone, valerolactone, and caprolactone (ε-caprolactone, etc.); ester-forming derivatives of these comonomer components (C １－６ alkyl ester derivatives, acid halides, acetylated products, etc.) can be mentioned.

[0020] In one embodiment, the content of (A) polybutylene terephthalate resin is preferably 10 to 85% by mass, more preferably 20 to 80% by mass, and even more preferably 30 to 70% by mass in 100% by mass of the total amount of the resin composition.

[0021] [(B) Carbodiimide compound] The resin composition according to the present embodiment contains (B) a carbodiimide compound, and the (B) carbodiimide compound contains (b1) a cyclic carbodiimide compound and (b2) an aromatic carbodiimide compound. By using (b1) a cyclic carbodiimide compound and (b2) an aromatic carbodiimide compound in combination and blending them with the polybutylene terephthalate resin in specific ratios and amounts described later, it is possible to provide a resin composition with better heat shock resistance while suppressing an increase in viscosity compared to blending the aromatic carbodiimide compound or the cyclic carbodiimide alone, and a molded article using the same.

[0022] (b1) Cyclic Carbodiimide Compounds In this specification, "(b1) Cyclic Carbodiimide Compounds" means carbodiimide compounds having a carbodiimide group in a cyclic structure. A cyclic carbodiimide compound may have multiple cyclic structures. One cyclic structure has one carbodiimide group (-N=C=N-), and its primary and secondary nitrogens are bonded by a bonding group. One cyclic structure has only one carbodiimide group. The number of atoms in the cyclic structure is preferably 8 to 50, more preferably 10 to 30, even more preferably 10 to 20, and particularly preferably 10 to 15. Here, the number of atoms in the cyclic structure means the number of atoms that directly constitute the ring structure; for example, 8 for an 8-membered ring, and 50 for a 50-membered ring. The number of atoms in the cyclic structure is preferably selected from the range of 10 to 30, more preferably 10 to 20, and particularly preferably 10 to 15.

[0023] (b1) The molecular weight of the cyclic carbodiimide compound is preferably 100 to 1,000. If the molecular weight is 100 or more, the (b1) cyclic carbodiimide compound has advantages in terms of structural stability and volatility. If the molecular weight is 1,000 or less, the synthesis in a dilution system is not required in the production of the cyclic carbodiimide, and the yield does not decrease easily, which is advantageous in terms of cost. From this viewpoint, it is more preferably 100 to 750, and even more preferably 250 to 750. Here, the molecular weight of the (b1) cyclic carbodiimide compound refers to the weight-average molecular weight if the (b1) cyclic carbodiimide compound has a molecular weight distribution.

[0024] In one embodiment, the (b1) cyclic carbodiimide compound is preferably a compound having a cyclic structure represented by the following general formula (I).

[0025] (In the formula, Q is a divalent to tetravalent bond group which may contain a heteroatom and / or substituents, an aliphatic group, an alicyclic group, an aromatic group, or a combination thereof).

[0026] In one embodiment, Q is -Ar ａ -O-X-O-Ar ｂ It is preferable that the group is represented by -. Ar ａand Ar ｂ is each independently a monocyclic or fused polycyclic alicyclic group, aromatic group, or heterocyclic group which may have a substituent, preferably a phenylene group or naphthalene-diyl group which may have a substituent. In this case, examples of the substituent include an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 15 carbon atoms, a halogen atom, a nitro group, an amide group, a hydroxyl group, an ester group, an ether group, an aldehyde group, etc., preferably an alkyl group having 1 to 6 carbon atoms or a phenyl group. When X has two cyclic structures, it is preferably an alkanediyl group. When it has four cyclic structures, it is preferably an alkanetetrayl group.

[0027] In one embodiment, the (b1) cyclic carbodiimide compound is preferably a compound represented by formula (II).

[0028]

[0029] In the formula, X is a tetravalent group represented by the following formula (i). In the formula, Ar １ ~Ar ４ are each independently a divalent monocyclic or fused polycyclic alicyclic group, aromatic group, or heterocyclic group which may have a substituent, preferably an orthophenylene group or 1,2-naphthalene-diyl group which may have a substituent.. Examples of the substituent include an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 15 carbon atoms, a halogen atom, a nitro group, an amide group, a hydroxyl group, an ester group, an ether group, an aldehyde group, etc. Also, when Ar １ ~Ar ４ is a heterocyclic group, the heterocyclic group contains a hetero atom selected from the group consisting of O, N, S, and P

[0030]

[0031] In one embodiment, specific examples of the (b1) cyclic carbodiimide compound that can be preferably used include the compounds shown below.

[0032]

[0033] (In the case where a cyclic carbodiimide compound is added to the main chain of the polymer, and n is the number of repeating units of the polymer.)

[0034]

[0035]

[0036]

[0037]

[0038] [(b2) Aromatic carbodiimide compounds] In this specification, "(b2) Aromatic carbodiimide compounds" means carbodiimide compounds whose main chain is aromatic. In other words, it means aromatic compounds having a carbodiimide group as a substituent. In this embodiment, the aromatic carbodiimide compounds include diphenylcarbodiimide, di-2,6-dimethylphenylcarbodiimide, N-triyl-N'-phenylcarbodiimide, di-p-nitrophenylcarbodiimide, di-p-aminophenylcarbodiimide, di-p-hydroxyphenylcarbodiimide, di-p-chlorophenylcarbodiimide, di-p-methoxyphenylcarbodiimide, di-3,4-dichlorophenylcarbodiimide, di-2,5-dichlorophenylcarbodiimide, di-o-chlorophenylcarbodiimide, p-phenylene-bis-di-o-triylcarbodiimide, p-phenylene-bis-dicyclohexylcarbodiimide, p-phenylene-bis-di-p-chlorophenylcarbodiimide, and ethylene-bis-diphenylcarbodiimide. Examples include mono or dicarbodiimide compounds such as poly(2,4'-diphenylmethanecarbodiimide), poly(4,4'-diphenylmethanecarbodiimide), poly(3,5'-dimethyl-4,4'-biphenylmethanecarbodiimide), poly(p-phenylenecarbodiimide), poly(m-phenylenecarbodiimide), poly(3,5'-dimethyl-4,4'-diphenylmethanecarbodiimide), poly(naphthylenecarbodiimide), poly(1,3-diisopropylphenylenecarbodiimide), poly(1-methyl-3,5-diisopropylphenylenecarbodiimide), poly(1,3,5-triethylphenylenecarbodiimide), and poly(triisopropylphenylenecarbodiimide), and two or more of these can be used in combination. Among these, di-2,6-dimethylphenylcarbodiimide, poly(4,4'-diphenylmethanecarbodiimide), poly(phenylenecarbodiimide), and poly(triisopropylphenylenecarbodiimide) are particularly preferred.(B) The carbodiimide compound may contain other carbodiimide compounds other than (b1) the cyclic carbodiimide compound and (b2) the aromatic carbodiimide compound, but preferably (B) the carbodiimide compound consists only of (b1) the cyclic carbodiimide compound and (b2) the aromatic carbodiimide compound.

[0039] [Total content of (B) carbodiimide compound] In the resin composition according to this embodiment, the total content of (b1) cyclic carbodiimide compound and (b2) aromatic carbodiimide compound is 0.6 to 2.0 parts by mass per 100 parts by mass of (A) polybutylene terephthalate resin. In one embodiment, the total content of (b1) cyclic carbodiimide compound and (b2) aromatic carbodiimide compound is preferably 0.7 to 2.0 parts by mass, more preferably 0.7 to 1.8 parts by mass, even more preferably 0.7 to 1.7 parts by mass, and particularly preferably 0.8 to 1.6 parts by mass per 100 parts by mass of (A) polybutylene terephthalate resin. By having the total content of (b1) cyclic carbodiimide compound and (b2) aromatic carbodiimide compound within the above range, it is easier to obtain a resin composition with superior heat shock resistance while suppressing viscosity increase. In one embodiment, the total content of (b1) cyclic carbodiimide compound and (b2) aromatic carbodiimide compound is preferably 0.1 to 5% by mass, more preferably 0.2 to 1% by mass, and even more preferably 0.3 to 1% by mass, based on 100% by mass of the total amount of the resin composition.

[0040] [(b1) Mass ratio of the cyclic carbodiimide compound to the (b2) aromatic carbodiimide compound [(b1) / (b2)]] In the resin composition according to this embodiment, the mass ratio of the (b1) cyclic carbodiimide compound to the (b2) aromatic carbodiimide compound [(b1) / (b2)] is 0.2 to 1.6. In one embodiment, the mass ratio of the (b1) cyclic carbodiimide compound to the (b2) aromatic carbodiimide compound [(b1) / (b2)] is preferably 0.22 to 1.6, more preferably 0.22 to 1.5, even more preferably 0.24 to 1.5, and particularly preferably 0.24 to 1.4. By having the mass ratio of the (b1) cyclic carbodiimide compound to the (b2) aromatic carbodiimide compound [(b1) / (b2)] within the above range, it is easier to obtain a resin composition with superior heat shock resistance while suppressing viscosity increase.

[0041] [(C) Elastomer] The resin composition according to this embodiment includes (C) elastomer. By combining (C) elastomer with (D) fibrous inorganic filler, which will be described later, the resin composition is given elasticity, and the balance between strength and toughness of the molded article obtained from the resin composition according to this embodiment can be improved, thereby further enhancing the resistance to heat shock. Examples of (C) elastomer include olefin-based elastomers, core-shell-based elastomers, diene-based elastomers, polyester-based elastomers, urethane-based elastomers, silicone-based elastomers, styrene-based elastomers, polyamide-based elastomers, etc., and one or more of these can be used in combination.

[0042] Examples of olefin-based elastomers include ethylene-propylene copolymers (EP copolymers), ethylene-butene copolymers, ethylene-octene copolymers, ethylene-propylene-diene copolymers (EPD copolymers), ethylene-propylene-butene copolymers, ethylene-vinyl acetate copolymers, copolymers containing at least one unit selected from EP copolymers and EPD copolymers, copolymers of olefins and (meth)acrylic monomers, ethylene-ethyl acrylate copolymers, ethylene-glycidyl methacrylate copolymers, α-olefin-α,β-unsaturated carboxylic acid (ester)-α,β-unsaturated carboxylic acid glycidyl ester ternary copolymers, and ethylene copolymers obtained by copolymerizing ethylene (co)polymer with maleic anhydride or glycidyl methacrylate. Preferred olefin-based elastomers include EP copolymers, EPD copolymers, and copolymers of olefins and (meth)acrylic monomers, with ethylene ethyl acrylate being particularly preferred from the viewpoint of fluidity and mold release properties. These olefin-based elastomers can be used individually or in combination of two or more types.

[0043] Core-shell elastomers are polymers composed of a core layer made up of rubber components (soft components) and a shell layer made up of hard components, with acrylic rubber being used as the rubber component of the core layer. The rubber component used in the core layer has a glass transition temperature (T ｇ The temperature is preferably below 0°C (for example, -10°C or below), more preferably below -20°C (for example, -180°C or higher and -25°C or below), and particularly preferably below -30°C (for example, -150°C or higher and -40°C or below).

[0044] When using acrylic rubber as the rubber component, polymers obtained by polymerizing acrylic monomers such as alkyl acrylates as the main component are preferred. The alkyl acrylates used as monomers for acrylic rubber include butyl acrylate and other acrylic acid C110 １－１２ Alkyl esters of acrylic acid are preferred, and C ２－６ Alkyl esters are more preferred.

[0045] Acrylic rubber may be a homopolymer or copolymer of acrylic monomers. If the acrylic rubber is a copolymer of acrylic monomers, it may be a copolymer of acrylic monomers with other acrylic monomers, or a copolymer of acrylic monomers with other unsaturated bond-containing monomers. If the acrylic rubber is a copolymer, it may also be a copolymer of crosslinkable monomers.

[0046] Vinyl polymers are preferably used for the shell layer. Vinyl polymers are obtained by polymerizing or copolymerizing at least one monomer selected from, for example, aromatic vinyl monomers, vinyl cyanide monomers, methacrylate monomers, and acrylic acid monomers. The core layer and shell layer of such a core-shell elastomer may be bonded together by graft copolymerization. This graft copolymerization is obtained, if necessary, by adding a graft cross-agent that reacts with the shell layer during polymerization of the core layer, thereby providing reactive groups to the core layer, and then forming the shell layer. When silicone rubber is used as the graft cross-agent, organosiloxanes having vinyl bonds or organosiloxanes having thiols are used, and acronoxysiloxane, methacryloxysiloxane, and vinylsiloxane are preferably used.

[0047] As polyester elastomers, both ester-ester type elastomers having polyester unit structures in both the hard and soft segments, and ester-ether type elastomers having polyether unit structures in the soft segments, are preferably used. However, the former is more preferable in terms of heat resistance, and the latter in terms of dimensional accuracy. Aromatic polyester units such as polybutylene terephthalate and polyethylene terephthalate can preferably be used as the polyester unit structure of the hard segment, aliphatic polyester units such as polyethylene adipate, polybutylene adipate, and polycaprolactone can preferably be used as the polyester unit structure of the soft segment, and polyethylene glycol and polytetramethylene glycol can preferably be used as the polyether unit structure of the soft segment, but are not limited to these.

[0048] Examples of urethane-based elastomers include, but are not limited to, block copolymers in which polyurethane obtained by reacting diisocyanates such as 4,4'-diphenylmethane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, tolylene diisocyanate, and hexamethylene diisocyanate with glycols such as ethylene glycol and tetramethylene glycol forms the hard segment, and polyethers such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol, or aliphatic polyesters such as polyethylene adipate, polybutylene adipate, and polycaprolactone form the soft segment.

[0049] Examples of styrene-based elastomers include acrylonitrile-styrene copolymers, acrylonitrile-butadiene-styrene copolymers, styrene-butadiene copolymers, styrene-butadiene-styrene copolymers, styrene-isoprene-styrene copolymers, styrene-ethylene-butadiene-styrene copolymers, and acrylonitrile-styrene-epoxy group-containing vinyl copolymers, which can be used individually or in combination of two or more.

[0050] Examples of polyamide elastomers include, but are not limited to, block copolymers in which nylon 6, nylon 66, nylon 11, nylon 12, etc. are used as hard segments and polyethers or aliphatic polyesters are used as soft segments. In addition, although not strictly classified as elastomers, aliphatic polyamides can also be used as polyamide elastomers.

[0051] In one embodiment, the content of (C) elastomer is preferably 1.0 part by mass or more and 50 parts by mass or less, more preferably 5 parts by mass or more and 40 parts by mass or less, even more preferably 10 parts by mass or more and 35 parts by mass or less, and particularly preferably 10 parts by mass or more and 30 parts by mass or less, per 100 parts by mass of (A) (polybutylene terephthalate resin). By having the content of (C) elastomer in the resin composition within the above range, the balance between strength and toughness of the molded article obtained from the resin composition can be improved, thereby further enhancing the resistance to heat shock. In one embodiment, the content of (C) elastomer is preferably 1 to 25% by mass, more preferably 2 to 20% by mass, and even more preferably 6 to 10% by mass, of 100% by mass of the total amount of the resin composition.

[0052] [(D) Fibrous Inorganic Filler] The resin composition according to this embodiment includes (D) a fibrous inorganic filler. By combining it with the (C) elastomer described above and blending it into the resin composition, the balance between strength and toughness of the molded product obtained from the resin composition according to this embodiment can be improved, thereby further enhancing the resistance to heat shock. Examples of (D) fibrous inorganic fillers include glass fibers, asbestos fibers, carbon fibers, silica fibers, silica-alumina fibers, zirconia fibers, boron nitride fibers, silicon nitride fibers, boron fibers, potassium titanate fibers, and metal fibrous materials such as stainless steel, aluminum, titanium, copper, and brass. When using these inorganic fibrous fillers, it is desirable to use a consolidating agent or surface treatment agent if necessary. In one embodiment, (D) the fibrous inorganic filler is preferably glass fiber. Any known glass fiber is preferably used as the glass fiber, and it is not dependent on the glass fiber diameter, shape such as cylindrical, cocoon-shaped cross section, or oval cross section, or the length and glass cutting method when used in the manufacture of chopped strands or roving. While the type of glass is not limited, E-glass or corrosion-resistant glass containing zirconium in its composition is preferably used.

[0053] In one embodiment, the length of the fibrous inorganic filler (D) is not particularly limited, but is preferably 0.2 mm or more, more preferably 2.0 mm or less, and even more preferably 0.3 mm or more and 1.5 mm or less. The cross-section of the fibrous inorganic filler (D) may be circular or elliptical. From the viewpoint of filling performance with respect to the thickness of the molded product and the gate diameter, the diameter of a circular filler is preferably 5 μm or more and 20 μm or less, and preferably 10 μm or more and 15 μm or less. In the case of an elliptical filler, the major and minor axes are not particularly limited, but the major axis is preferably 10 μm or more and 26 μm or less, more preferably 12 μm or more and 20 μm or less, and the minor axis is preferably 5 μm or more and 13 μm or less, and even more preferably 6 μm or more and 10 μm or less. The length, cross-sectional diameter, major axis, and minor axis of the fibrous inorganic filler (D) can be calculated using a scanning electron microscope and image processing software, and the arithmetic mean measured for 1000 pieces of fibrous inorganic filler (C) is used. (D) The length, cross-sectional diameter, or major and minor axes of the fibrous inorganic filler can be taken from the manufacturer's catalog values. If the fibrous inorganic filler is circular, the resin composition can be ashed at approximately 600°C, the ashed residue can be dispersed in a 5% by mass polyethylene glycol aqueous solution, and then transferred to a petri dish. Images of 1000 fibrous inorganic fillers in the ashed residue can be captured from a CCD camera to a PC, and the arithmetic mean can be obtained using an image processing method with an image measuring instrument ("LUZEX AP" manufactured by Nireco Corporation).

[0054] In one embodiment, the content of (D) fibrous inorganic filler is preferably 20 parts by mass or more and 150 parts by mass or less, more preferably 30 parts by mass or more and 130 parts by mass or less, and more preferably 40 parts by mass or more and 110 parts by mass or less, per 100 parts by mass of polybutylene terephthalate resin. By having the content of (D) fibrous inorganic filler within the above range, the balance between strength and toughness of the molded article obtained from the resin composition can be improved, thereby further enhancing the resistance to heat shock. In one embodiment, the content of (D) fibrous inorganic filler is preferably 10 to 60% by mass, more preferably 15 to 40% by mass, and even more preferably 25 to 30% by mass, of 100% by mass of the total amount of the resin composition.

[0055] [Other Components] The resin compositions of this disclosure may also contain other polymers, other fillers, and known substances commonly added to synthetic resins, such as flame retardants, flame retardant aids, epoxy resins, anti-dripping agents, lubricants, plasticizers, stabilizers, colorants, antioxidants, ultraviolet absorbers, antistatic agents, dyes, pigments, etc., as appropriate, insofar as they do not impair the effects of this disclosure, depending on the required performance.

[0056] Other polymers refer to polymers other than (A) polybutylene terephthalate resin, (B) carbodiimide compounds, and (C) polymers that constitute elastomers, for example, epoxy group-containing copolymers. Other fillers refer to fillers other than (D) fibrous inorganic fillers, for example, organic fillers, carbon black, etc.

[0057] (E) Flame retardant and (F) Flame retardant aid) In one embodiment, the resin composition preferably contains (E) a flame retardant and (F) a flame retardant aid. By including (E) a flame retardant and (F) a flame retardant aid, a resin composition with superior flame retardancy can be obtained.

[0058] (E) As for flame retardants, those commonly used as flame retardants can be used. Specifically, halogen-based flame retardants include brominated epoxy flame retardants, brominated polyacrylate flame retardants, brominated polystyrene flame retardants, brominated polyphenylene ether flame retardants, brominated polycarbonate flame retardants, brominated biphenyl ether flame retardants, and brominated diphthalimide flame retardants. Non-halogen-based flame retardants include phosphate ester flame retardants, calcium or aluminum salts of phosphinates or diphosphinic acid, and red phosphorus. Among these, brominated epoxy flame retardants and brominated polyacrylate flame retardants are particularly preferred from the viewpoint of heat shock resistance.

[0059] In one embodiment, (E) the flame retardant is preferably one or more flame retardants selected from brominated epoxy flame retardants and brominated acrylate flame retardants. As the brominated epoxy flame retardant, for example, brominated versions of aromatic epoxy compounds (such as biphenyl-type epoxy compounds, bisphenol A-type epoxy compounds, phenol novolac-type epoxy compounds, and cresol novolac-type epoxy compounds) containing one or more epoxy groups in one molecule can be used. The brominated epoxy flame retardants can be used individually or in combination of two or more.

[0060] As a brominated acrylate-based flame retardant, for example, one having a structure obtained by copolymerizing a bromine-containing benzyl acrylate with a benzyl methacrylate having a similar structure can be used. Examples of bromine-containing benzyl acrylates include pentabromobenzyl acrylate, tetrabromobenzyl acrylate, tribromobenzyl acrylate, or mixtures thereof. Among these, pentabromobenzyl acrylate is preferred. Examples of benzyl methacrylate copolymerizable with bromine-containing benzyl acrylates include methacrylates corresponding to the above-mentioned acrylates. Furthermore, copolymerization with vinyl monomers is also possible. Examples of vinyl monomers include acrylic acid esters such as acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, and benzyl acrylate; methacrylic acid esters such as methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, and benzyl methacrylate; unsaturated carboxylic acids or their anhydrides such as styrene, acrylonitrile, fumaric acid, and maleic acid; vinyl acetate; and vinyl chloride. Crosslinkable vinyl monomers, xylylenediacrylate, xylylenedimethacrylate, tetrabrom xylylenediacrylate, tetrabrom xylylenedimethacrylate, butadiene, isoprene, and divinylbenzene can also be used. These are preferably used in amounts equal to or less than equimolar, and more preferably 0.5 times the molar amount, relative to benzyl acrylate or benzyl methacrylate. Brominated acrylate flame retardants can be used individually or in combination of two or more types.

[0061] (F) Examples of flame retardants include antimony-based flame retardants, metal borate salt-based flame retardants, and nitrogen-based flame retardants. Typically, antimony-based or metal borate salt-based flame retardants are used with halogen-based flame retardants, and nitrogen-based flame retardants are used with non-halogen-based flame retardants.

[0062] Examples of antimony-based flame retardants include antimony trioxide, antimony pentoxide, or sodium antimonate. Examples of metal borate salt-based flame retardant additives include calcium borate, sodium borate, and zinc borate. Examples of nitrogen-based flame retardant additives include salts of triazine compounds with cyanuric acid or isocyanuric acid (e.g., melamine cyanurate).

[0063] In one embodiment, (F) the flame retardant is preferably an antimony oxide compound. From the viewpoint of heat shock resistance, antimony pentoxide is particularly preferred as the antimony oxide compound.

[0064] In one embodiment, the content of (E) flame retardant is preferably 1 to 50 parts by mass, more preferably 10 to 40 parts by mass, preferably 20 to 35 parts by mass, and most preferably 25 to 35 parts by mass, with respect to 100 parts by mass of (A) polybutylene terephthalate resin.

[0065] In one embodiment, the content of (F) flame retardant aid is preferably 1 to 50 parts by mass, more preferably 5 to 40 parts by mass, preferably 5 to 30 parts by mass, and most preferably 10 to 20 parts by mass, per 100 parts by mass of (A) polybutylene terephthalate resin.

[0066] (G) Epoxy Resin In one embodiment, the resin composition preferably contains an epoxy resin. Including an epoxy resin makes it easier to obtain a resin composition with superior heat shock resistance. Examples of epoxy resins include biphenyl-type epoxy resin, bisphenol A-type epoxy resin, phenol novolac-type epoxy resin, and cresol novolac-type epoxy resin, and it is preferable to use one or more selected from these. The epoxy resin may be used alone, or two or more may be used in any combination. The epoxy equivalent of the epoxy resin is preferably 600 to 1500 g / equivalent (g / eq). The epoxy equivalent can be measured by potentiometric titration with glacial acetic acid and cetyltrimethylammonium bromide in accordance with JIS K-7236.

[0067] In one embodiment, the epoxy resin content is preferably 0.1 parts by mass or more and 10 parts by mass or less, more preferably 0.5 parts by mass or more and 5 parts by mass or less, even more preferably 1 part by mass or more and 5 parts by mass or less, and particularly preferably 1 part by mass or more and 2 parts by mass or less, based on 100 parts by mass of (A) polybutylene terephthalate resin.

[0068] ((H) Anti-dripping agent) In one embodiment, the resin composition may contain (H) an anti-dripping agent. By including (H) an anti-dripping agent, dripping during combustion can be prevented, and the flame retardancy of the resin composition is more easily improved. Examples of anti-dripping agents include fluorine-containing monomers (tetrafluoroethylene, chlorotrifluoroethylene, vinylidene fluoride, hexafluoropropylene, perfluoroalkyl vinyl ether, etc.) alone or copolymers thereof, or copolymers of the fluorine-containing monomer with other copolymerizable monomers (olefin monomers such as ethylene and propylene, acrylic monomers such as (meth)acrylate, etc.). Polytetrafluoroethylene is preferred due to its availability, high effectiveness, and ease of handling. In one embodiment, the content of the anti-dripping agent is preferably 0.1 parts by mass or more and 5 parts by mass or less, and more preferably 1 part by mass or more and 2 parts by mass or less, per 100 parts by mass of (A) polybutylene terephthalate resin.

[0069] (Lubricant) In one embodiment, the resin composition may contain a lubricant. Including a lubricant makes it easier to improve the moldability of the resin composition. A fatty acid-based lubricant is preferred as the lubricant. In one embodiment, the lubricant content is preferably 0.1 parts by mass or more and 1 part by mass or less, and more preferably 0.5 parts by mass or more and 1 part by mass or less, per 100 parts by mass of (A) polybutylene terephthalate resin.

[0070] (Plasticizer) In one embodiment, the resin composition may contain a plasticizer. Including a plasticizer makes it easier to improve the moldability of the resin composition. A pyromellitic acid mixed linear alkyl ester is preferred as the plasticizer. In one embodiment, the content of the plasticizer is preferably 1 to 20 parts by mass, and more preferably 5 to 10 parts by mass, per 100 parts by mass of (A) polybutylene terephthalate resin.

[0071] (Stabilizers) In one embodiment, the resin composition may contain stabilizers. Including stabilizers makes it easier to improve the durability and stability of molded articles containing the resin composition. Examples of stabilizers include organic acid salts, inorganic acid salts, oxides, and hydroxides of alkali metals and alkaline earth metals. Specifically, examples of alkali metal compounds include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium bicarbonate, potassium bicarbonate, lithium bicarbonate, sodium carbonate, potassium carbonate, lithium carbonate, sodium acetate, potassium acetate, lithium acetate, sodium stearate, potassium stearate, lithium stearate, sodium borohydride, lithium borohydride, sodium phenylborohydrate, sodium benzoate, potassium benzoate, lithium benzoate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, dilithium hydrogen phosphate, disodium salt, dipotassium salt, dilithium salt of bisphenol A, sodium salt, potassium salt, lithium salt of phenol, and the like. Furthermore, examples of alkaline earth compounds include calcium hydroxide, barium hydroxide, magnesium hydroxide, strontium hydroxide, calcium bicarbonate, barium bicarbonate, magnesium bicarbonate, strontium bicarbonate, calcium carbonate, barium carbonate, magnesium carbonate, strontium carbonate, calcium acetate, barium acetate, magnesium acetate, strontium acetate, calcium stearate, barium stearate, magnesium stearate, and strontium stearate. Among these compounds, potassium acetate and calcium acetate are preferred. In one embodiment, the content of the stabilizer is preferably 0.001 parts by mass or more and 0.1 parts by mass or less, and more preferably 0.05 parts by mass or more and 0.015 parts by mass or less, per 100 parts by mass of (A) polybutylene terephthalate resin.

[0072] (Colorants) In one embodiment, the resin composition may contain a colorant. Examples of colorants include inorganic pigments [black pigments such as carbon black (e.g., acetylene black, lamp black, thermal black, furnace black, channel black, Ketjen black, etc.), red pigments such as iron oxide, orange pigments such as molybdate orange, white pigments such as titanium dioxide, etc.], and organic pigments (yellow pigments, orange pigments, red pigments, blue pigments, green pigments, etc.). In one embodiment, the content of the colorant is preferably 0.1 parts by mass or more and 5 parts by mass or less, and more preferably 1 part by mass or more and 1.5 parts by mass or less, per 100 parts by mass of (A) polybutylene terephthalate resin.

[0073] (Antioxidant) In one embodiment, the resin composition may contain an antioxidant. Including an antioxidant makes it easier to improve the durability and stability of the molded article containing the resin composition. Examples of antioxidants include hindered phenol antioxidants, thioether antioxidants, and hindered amine antioxidants, and it is preferable to include a hindered phenol antioxidant. In one embodiment, the content of the antioxidant is preferably 0.1 parts by mass or more and 5 parts by mass or less, and more preferably 0.1 parts by mass or more and 1 part by mass or less, per 100 parts by mass of (A) polybutylene terephthalate resin.

[0074] (Method for manufacturing the resin composition) The resin composition according to this embodiment can be manufactured by various methods conventionally known as methods for manufacturing thermoplastic resin compositions. A suitable method for manufacturing the resin composition is, for example, a method in which each component is melt-kneaded using a melt-kneading device such as a single-screw or twin-screw extruder and then extruded into pellets.

[0075] Furthermore, the (B) carbodiimide compound can also be formulated as a masterbatch with a thermoplastic resin as the matrix. The masterbatch of the (B) carbodiimide compound preferably uses polybutylene terephthalate resin as the matrix, but masterbatches using other thermoplastic resins as the matrix can also be used.

[0076] The resin composition according to this embodiment is measured in accordance with ISO 11443 at a temperature of 260°C and a shear rate of 1000 sec. －１ The melt viscosity can be 0.4 kPa·s or less, more preferably 0.38 kPa·s or less, and even more preferably 0.36 kPa·s or less. Because the resin composition according to this embodiment exhibits such a melt viscosity, it shows excellent fluidity during molding and can be suitably used in injection molding such as insert molding, resulting in fewer molding defects such as short shots.

[0077] The resin composition obtained according to this embodiment has excellent resistance to thermal shock and is therefore suitable for use in various applications such as insert parts. In particular, it is suitable for use as a material for insert molded products such as busbars for automotive applications because it is less prone to cracking due to thermal shock even when subjected to drastic temperature changes.

[0078] <Molded Article> The molded article according to this embodiment contains the above-mentioned resin composition. By containing the above-mentioned resin composition, the molded article according to this embodiment exhibits excellent heat shock resistance and long-term reliability as a material. In one embodiment, the molded article is preferably an insert molded article. Because the expansion and contraction rates due to temperature changes (so-called linear expansion coefficients) differ greatly between polybutylene terephthalate resin and conductive members such as metal, cracks are likely to occur with temperature changes during use. In particular, when the conductive member embedded in the polybutylene terephthalate resin is a thin insert part (for example, a plate-shaped member with an average thickness of 3 mm or less), it has been difficult to obtain an insert molded article with sufficient heat shock resistance for practical use. The molded article of this embodiment, which has excellent heat shock resistance, is an insert molded article, and therefore cracks due to heat shock are less likely to occur even when subjected to drastic temperature changes, making it suitable for use as an automotive part.

[0079] (Applications) The molded product according to this embodiment is suitable for general home appliances, electrical and electronic components incorporated into office automation equipment, mechanical components, automobile parts, etc., as it is possible to obtain a molded product with excellent heat shock resistance.

[0080] Furthermore, it is suitably used as a component for electric vehicles, where durability for automobiles and flame retardancy as an electrical and electronic component are required. For example, although not particularly limited, it is suitable as a material for cases housing busbars, power modules, boost DC / DC converters, buck DC / DC converters, capacitors, insulators, motor terminal blocks, batteries, electric compressors, battery current sensors, and junction blocks.

[0081] A non-limiting list of exemplary embodiments and combinations of exemplary embodiments of the present disclosure is disclosed below. [1] A resin composition comprising (A) a polybutylene terephthalate resin, (B) a carbodiimide compound, (C) an elastomer, and (D) a fibrous inorganic filler, wherein the (B) carbodiimide compound comprises (b1) a cyclic carbodiimide compound and (b2) an aromatic carbodiimide compound, the total content of the (b1) cyclic carbodiimide compound and the (b2) aromatic carbodiimide compound is 0.6 to 2.0 parts by mass per 100 parts by mass of the (A) polybutylene terephthalate resin, and the mass ratio [(b1) / (b2)] of the (b1) cyclic carbodiimide compound to the (b2) aromatic carbodiimide compound is 0.2 to 1.6. [2] The resin composition according to [1], wherein the amount of (B) carbodiimide compound is 0.8 to 1.8 parts by mass per 100 parts by mass of (A) polybutylene terephthalate resin. [3] The resin composition according to [1] or [2], wherein the mass ratio [(b1) / (b2)] of the (b1) cyclic carbodiimide compound to the (b2) aromatic carbodiimide compound is 0.22 to 1.5. [4] The resin composition according to any one of [1] to [3], wherein (D) fibrous inorganic filler is glass fiber. [5] The resin composition according to any one of [1] to [4], further comprising a flame retardant and a flame retardant aid. [6] The resin composition according to any one of [1] to [5], further comprising an epoxy resin. [7] A molded article comprising the resin composition according to any one of [1] to [6]. [8] The molded article according to [7], which is an insert molded article.

[0082] The present disclosure will be further illustrated by the following examples, but these examples will not limit the interpretation of the present disclosure.

[0083] <Preparation of Resin Compositions> The raw materials were mixed in the proportions shown in Tables 1 to 3, and extruded using a twin-screw extruder (TEX 30, manufactured by Japan Steel Works) at a cylinder temperature of 260°C and screw rotation of 130 rpm to produce pellets of each resin composition for the examples and comparative examples. A blank space in Tables 1 to 3 indicates that the component was not included.

[0084] [(A): Polybutylene terephthalate (PBT) resin] - Polybutylene terephthalate (manufactured by Polyplastics Co., Ltd., intrinsic viscosity 0.68 dL / g, carboxylic acid terminal group content 13 meq / kg) [(B): Carbodiimide compounds] - (b1): Cyclic carbodiimide (manufactured by Teijin Limited, "Carbodista TCC-NP") - (b2): Aromatic carbodiimide (manufactured by Lanxess K.K., "STABAXOL P100") [(C): Elastomer] - Olefin elastomer (manufactured by NOF Corporation, "Modiper A5300") [(D): Fibrous inorganic filler] - Glass fiber (manufactured by Nippon Electric Glass Co., Ltd., "ECS03T-127") [(E) Flame retardant] - (1): Brominated benzyl acrylate resin (manufactured by ICL JAPAN Co., Ltd., "FR-1025") • (2): Brominated epoxy resin (manufactured by Ushin Polymer Co., Ltd., "CXB-1500C") [(F) Flame retardant additive] • (1): Antimony trioxide (manufactured by Nippon Seikou Co., Ltd., "PATOX-M") • (2): Antimony pentoxide (manufactured by Nissan Chemical Corporation, "Sun Epoch NA1030") [(G) Epoxy resin] • Bisphenol A type epoxy resin (manufactured by Tomoe Engineering Co., Ltd., "YD014C"), epoxy equivalent 938 g / equivalent [(H) Anti-dripping agent] • Polytetrafluoroethylene resin (manufactured by AGC Inc., "Fluon CD097E") [Lubricant] • Special fatty acid ester (manufactured by Riken Vitamin Co., Ltd., "Rikemar B-74") [Plasticizer] • Pyromellitic acid mixed alcohol ester (manufactured by ADEKA Corporation, "ADEKA Sizer UL-100") [Stabilizer] • Potassium acetate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) [Coloring agent] • Carbon black (manufactured by Mitsubishi Chemical Corporation, "MA600B") [Antioxidant] • Hindered phenol antioxidant (manufactured by BASF Japan Ltd., "IRGANOX1010")

[0085] <Melting Viscosity> After drying each pellet prepared above at 140°C for 3 hours, the pellets were melted in accordance with ISO 11443 using a Capillograph 1B (manufactured by Toyo Seiki Seisakusho Co., Ltd.) at a barrel temperature of 260°C, with a capillary diameter of φ1 mm x 20 mm L and a shear rate of 1000 sec. －１ The melt viscosity was measured.

[0086] <Tensile Strength Retention Rate (Hydrolysis Resistance)> After drying each pellet prepared above at 140°C for 3 hours, ISO 3167 tensile test specimens were injection molded using an injection molding machine (Sumitomo Heavy Industries, Ltd., "SE100EV-A") at a resin temperature of 260°C and a mold temperature of 80°C, and the tensile strength was measured in accordance with ISO 527-1,2. In addition, the injection-molded test specimens were treated in a high-accelerated life tester (Hirayama Seisakusho, "PC-R8D") at 121°C and 100% RH for 100 hours, and the tensile strength after treatment was measured, and the retention rate of tensile strength before and after treatment [(Tensile strength value after treatment) / (Tensile strength value before treatment)] was calculated. A higher retention rate before and after treatment indicates superior hydrolysis resistance.

[0087] <Heat Shock Resistance> Using the pellets prepared above and L-shaped metal insert parts, test pieces as shown in Figure 1 were insert-molded by injection molding. The resulting molded test pieces were subjected to a heat shock resistance test using a thermal shock tester (Hitachi Appliances, "ES-107LH"), in which the process of heating to 140°C for 1 hour and 30 minutes, then cooling to -40°C for 1 hour and 30 minutes, and then heating back up to 140°C constituted one cycle. The number of cycles until cracks appeared in the molded product (shown as "Number of Cycles" in Tables 1 to 3) was measured. A larger number of cycles until cracks appear in the molded product indicates superior heat shock resistance. The results are shown in Tables 1 to 3.

[0088]

[0089]

[0090]

[0091] As shown in Tables 1 to 3, molded articles using the resin compositions of the examples that satisfy the configuration of this embodiment had approximately twice as many cycles until cracks appeared in the molded articles compared to molded articles using the resin compositions of the comparative examples that do not satisfy the configuration of this embodiment. In other words, molded articles with superior heat shock resistance were obtained using the resin compositions of this embodiment. Furthermore, despite containing a cyclic carbodiimide compound (b1) known to increase melt viscosity, the polybutylene terephthalate resin composition of the examples showed suppressed increases in melt viscosity. In addition, the resin compositions of the examples generally had higher tensile strength retention rates compared to the resin compositions of the comparative examples. In other words, molded articles using the resin compositions of the examples generally exhibited superior hydrolysis resistance.

[0092] The resin composition of this embodiment can produce molded products with superior heat shock resistance, making it suitable for various applications such as insert parts, and thus possessing industrial applicability.

Claims

1. A resin composition comprising (A) a polybutylene terephthalate resin, (B) a carbodiimide compound, (C) an elastomer, and (D) a fibrous inorganic filler, wherein the (B) carbodiimide compound comprises (b1) a cyclic carbodiimide compound and (b2) an aromatic carbodiimide compound, the total content of the (b1) cyclic carbodiimide compound and the (b2) aromatic carbodiimide compound is 0.6 to 2.0 parts by mass per 100 parts by mass of the (A) polybutylene terephthalate resin, and the mass ratio [(b1) / (b2)] of the (b1) cyclic carbodiimide compound to the (b2) aromatic carbodiimide compound is 0.2 to 1.

6.

2. The resin composition according to claim 1, wherein the amount of (B) carbodiimide compound is 0.8 to 1.8 parts by mass per 100 parts by mass of (A) polybutylene terephthalate resin.

3. The resin composition according to claim 1 or 2, wherein the mass ratio [(b1) / (b2)] of the cyclic carbodiimide compound (b1) to the aromatic carbodiimide compound (b2) is 0.22 to 1.

5.

4. (D) The resin composition according to claim 1 or 2, wherein the fibrous inorganic filler is glass fiber.

5. The resin composition according to claim 1 or 2, further comprising (E) a flame retardant and (F) a flame retardant aid.

6. The resin composition according to claim 1 or 2, further comprising (G) an epoxy resin.

7. A molded article comprising the resin composition according to claim 1 or 2.

8. The molded article according to claim 7, which is an insert molded article.

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