Polybutylene terephthalate resin composition and method for producing the same, and resin molded article

Abstract

To provide a polybutylene terephthalate resin composition which enables molding of a resin molded article that is excellent in both flame resistance and hydrolysis resistance.SOLUTION: A polybutylene terephthalate resin composition contains a polybutylene terephthalate resin (A) having an intrinsic viscosity of 0.70 dL / g or more and 1.10 dL / g or less, and a carboxylic acid terminal content of 18 meq / kg or less, a bromine-based flame retardant (B), an antimony-based flame retardant assistant (C), and an inorganic filler (D) which is surface-treated with a sizing agent containing a polymer including a structural unit derived from a carboxylic acid and / or a carboxylic acid anhydride and an epoxy resin, wherein the bromine-based flame retardant contains a brominated epoxy-based flame retardant and / or a brominated acrylate-based flame retardant, and the polybutylene terephthalate resin composition contains 10 to 100 pts.mass of the inorganic filler (D) with respect to 100 pts.mass of the polybutylene terephthalate resin (A).SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a polybutylene terephthalate resin composition, a method for producing the same, and a resin molded article. [Background technology]

[0002] Polybutylene terephthalate resin (hereinafter also referred to as "PBT resin") is used in many applications because of its excellent properties such as heat resistance, chemical resistance, electrical properties, mechanical properties, and moldability. Specific applications include various automotive electrical components (various control units, various sensors, ignition coils, etc.), various electrical and electronic components (connectors, switch components, relay components, coil components, etc.), and other electrical and electronic components such as home appliances (casings, insulating materials, etc.). In these applications, flame retardancy is required for the materials used to prevent fires caused by electric leakage, etc., and thus flame-retardant PBT resin compositions containing various flame retardants are used. In addition, in recent years, with the shift to electric vehicles, there has been an increasing demand for flame retardancy in motor and battery-related resin components.

[0003] A commonly known method for making a PBT resin composition flame retardant is to add a halogenated flame retardant such as a halogenated epoxy flame retardant or a non-halogenated flame retardant. Patent Document 1 describes a polybutylene terephthalate resin composition that uses a halogenated epoxy flame retardant.

[0004] On the other hand, since PBT resin has an ester group in the molecule, its physical properties tend to be easily deteriorated by hydrolysis in a high-temperature and high-humidity environment. Therefore, improvements have been made using epoxy resins or carbodiimide compounds. Patent Document 2 describes the use of a PBT resin having a terminal carboxyl group amount of 1 to 9 meq / kg or less, a carbodiimide compound, and a halogenated flame retardant as a flame-retardant PBT resin composition having excellent hydrolysis resistance and fluidity.

[0005] It is also known that the hydrolysis resistance of glass fibers themselves can be improved by using an epoxy resin as a sizing agent (see Patent Documents 3 and 4). Patent Document 3 shows the use of glass fibers that have been surface-treated with a sizing agent containing, as essential components, a copolymer of an unsaturated carboxylic acid and / or an anhydride of an unsaturated carboxylic acid with an unsaturated monomer, and an epoxy resin. Patent Document 4 shows that surface-treated glass fibers containing a novolac-type epoxy resin have excellent long-term heat resistance. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-024880 [Patent Document 2] Patent Publication No. 2022-066647 [Patent Document 3] JP 2003-201671 A [Patent Document 4] JP 2015-129073 A Summary of the Invention [Problem to be solved by the invention]

[0007] As described above, there has been a demand for further improvements in the flame retardancy and hydrolysis resistance of PBT resin compositions in line with the shift to electric vehicles and the longer life spans of electrical and electronic products.

[0008] The present invention has been made in consideration of the above-mentioned problems in the conventional art, and an object of the present invention is to provide a polybutylene terephthalate resin composition capable of molding a resin molded article having both excellent flame retardancy and hydrolysis resistance, a method for producing the same, and a resin molded article obtained by molding the resin composition. [Means for solving the problem]

[0009] As a result of intensive research aimed at solving the above-mentioned problems, the present inventors have found that flame retardancy and hydrolysis resistance can be significantly improved compared to conventional methods by using a PBT resin composition containing a PBT resin having an intrinsic viscosity of 0.70 dL / g or more and 1.10 dL / g or less and a carboxylic acid terminal group amount of 18 meq / kg or less, a brominated epoxy flame retardant and / or a brominated acrylate flame retardant, an antimony-based flame retardant auxiliary, and glass fibers that have been surface-treated with a sizing agent containing a polymer containing structural units derived from carboxylic acid, etc., and an epoxy resin, and have thus completed the present invention.

[0010] One aspect of the present invention that solves the above problems is as follows: (1) A flame retardant composition comprising: a polybutylene terephthalate resin (A) having an intrinsic viscosity of 0.70 dL / g or more and 1.10 dL / g or less and a carboxylic acid end group amount of 18 meq / kg or less; a bromine-based flame retardant (B); an antimony-based flame retardant auxiliary (C); and an inorganic filler (D) that is surface-treated with a sizing agent that contains a polymer containing a structural unit derived from a carboxylic acid and / or a carboxylic acid anhydride and an epoxy resin; the brominated flame retardant comprises a brominated epoxy flame retardant and / or a brominated acrylate flame retardant; A polybutylene terephthalate resin composition comprising 10 to 100 parts by mass of the inorganic filler (D) based on 100 parts by mass of the polybutylene terephthalate resin (A).

[0011] (2) The polybutylene terephthalate resin composition according to (1) above, further comprising 0.5 to 3.0 parts by mass of an aromatic carbodiimide and / or an epoxy compound per 100 parts by mass of the polybutylene terephthalate resin (A).

[0012] (3) The polybutylene terephthalate resin composition according to (1) or (2), wherein the inorganic filler (D) is fibrous and has an average fiber diameter of 3 to 50 μm, and the content of the sizing agent per 100 parts by mass of the inorganic filler (D) is 0.1 to 3.0 parts by mass.

[0013] (4) A resin molded product comprising the polybutylene terephthalate resin composition according to (1) or (2).

[0014] (5) A method for producing the polybutylene terephthalate resin composition according to (1) or (2), comprising the steps of: A step A of obtaining a polybutylene terephthalate resin (A) having an intrinsic viscosity of 0.70 dL / g or more and 1.10 dL / g or less and a carboxylic acid terminal group amount of 18 meq / kg or less, using 1,4-butanediol and / or terephthalic acid obtained by chemical recycling; and and step B of mixing the polybutylene terephthalate resin (A), a bromine-based flame retardant (B), an antimony-based flame retardant auxiliary (C), and an inorganic filler (D) that has been surface-treated with a sizing agent containing a polymer containing a structural unit derived from a carboxylic acid and / or a carboxylic acid anhydride and an epoxy resin, The brominated flame retardant (B) comprises a brominated epoxy flame retardant and / or a brominated acrylate flame retardant, A method for producing a polybutylene terephthalate resin composition, wherein in the step B, 10 to 100 parts by mass of the inorganic filler (D) is mixed with 100 parts by mass of the polybutylene terephthalate resin (A).

[0015] (6) A method for producing the polybutylene terephthalate resin composition according to (1) or (2), comprising the steps of: A step of obtaining a polybutylene terephthalate resin (A) obtained by material recycling, the polybutylene terephthalate resin (A) having an intrinsic viscosity of 0.70 dL / g or more and 1.10 dL / g or less and a carboxylic acid terminal group amount of 18 meq / kg or less; and step B of mixing the polybutylene terephthalate resin (A), a bromine-based flame retardant (B), an antimony-based flame retardant auxiliary (C), and an inorganic filler (D) that has been surface-treated with a sizing agent containing a polymer containing a structural unit derived from a carboxylic acid and / or a carboxylic acid anhydride and an epoxy resin, The brominated flame retardant (B) comprises a brominated epoxy flame retardant and / or a brominated acrylate flame retardant, A method for producing a polybutylene terephthalate resin composition, wherein in the step B, 10 to 100 parts by mass of the inorganic filler (D) is mixed with 100 parts by mass of the polybutylene terephthalate resin (A). Effect of the Invention

[0016] According to the present invention, it is possible to provide a polybutylene terephthalate resin composition capable of molding a resin molded article having both excellent flame retardancy and hydrolysis resistance, a method for producing the same, and a resin molded article obtained by molding the resin composition. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] <Polybutylene terephthalate resin composition> The polybutylene terephthalate resin composition of the present embodiment includes a polybutylene terephthalate resin (A) having an intrinsic viscosity of 0.70 dL / g or more and 1.10 dL / g or less and a carboxylic acid end group amount of 18 meq / kg or less, a brominated flame retardant (B), an antimony-based flame retardant auxiliary (C), and an inorganic filler (D) surface-treated with a sizing agent containing a polymer containing a structural unit derived from a carboxylic acid and / or a carboxylic acid anhydride and an epoxy resin. The brominated flame retardant includes a brominated epoxy flame retardant and / or a brominated acrylate flame retardant. The inorganic filler (D) is contained in an amount of 10 to 100 parts by mass per 100 parts by mass of the polybutylene terephthalate resin (A).

[0018] The PBT resin composition of this embodiment has excellent flame retardancy by containing a bromine-based flame retardant (B) and an antimony-based flame retardant auxiliary (C). In addition, by using a PBT resin having an intrinsic viscosity of 0.70 dL / g or more and 1.10 dL / g or less and a carboxylic acid end group amount of 18 meq / kg or less, and by containing a polymer containing a structural unit derived from a carboxylic acid and / or a carboxylic acid anhydride in the sizing agent of the inorganic filler (C), the composition has excellent hydrolysis resistance. Note that, although some flame retardants such as phosphorus-based flame retardants and metal hydroxides have a negative effect on hydrolysis resistance, the bromine-based flame retardant (B) contained in the PBT resin composition of this embodiment can impart flame retardancy without reducing hydrolysis resistance. Each component of the PBT resin composition of the present embodiment will be described below.

[0019] [Polybutylene terephthalate resin (A)] The PBT resin (A) is a resin obtained by polycondensation of a dicarboxylic acid component containing at least terephthalic acid or its ester-forming derivative (C1-6 alkyl ester, acid halide, etc.) and a glycol component containing at least an alkylene glycol having 4 carbon atoms (1,4-butanediol) or its ester-forming derivative (acetylated product, etc.). The PBT resin (A) is not limited to a homopolybutylene terephthalate resin, and may be a copolymer containing 60 mol % or more (particularly 75 mol % or more and 95 mol % or less) of butylene terephthalate units. In this embodiment, 1,4-butanediol and terephthalic acid or terephthalic acid alkyl ester, which are raw materials for the PBT resin, may be derived from either fossil resources or biomass resources.

[0020] The amount of carboxylic acid end groups in the PBT resin (A) is 18 meq / kg or less, preferably 2 meq / kg or more and 18 meq / kg or less, and more preferably 5 meq / kg or more and 13 meq / kg or less. By using a PBT resin having a terminal carboxyl group amount in this range, the resulting PBT resin composition is less susceptible to strength reduction due to hydrolysis in a humid and hot environment. In order to ensure adhesion to an inorganic filler surface-treated with a sizing agent, the amount of carboxylic acid end groups is preferably 2 meq / kg or more. If the amount of carboxylic acid end groups is less than 2 meq / kg, adhesion to glass fibers is reduced, resulting in a reduction in strength.

[0021] The intrinsic viscosity (IV) of the PBT resin is preferably 0.70 dL / g or more and 1.10 dL / g or less, more preferably 0.80 dL / g or more and 0.95 dL / g or less, and even more preferably 0.83 dL / g or more and 0.90 dL / g or less. When a PBT resin having an intrinsic viscosity in such a range is used, the obtained PBT resin composition has excellent hydrolysis resistance and moldability. In addition, the intrinsic viscosity can be adjusted by blending PBT resins having different intrinsic viscosities. For example, a PBT resin having an intrinsic viscosity of 0.85 dL / g can be prepared by blending a PBT resin having an intrinsic viscosity of 1.00 dL / g with a PBT resin having an intrinsic viscosity of 0.80 dL / g. The intrinsic viscosity (IV) of the PBT resin (A) can be measured, for example, in o-chlorophenol at a temperature of 35°C.

[0022] In the PBT resin (A), examples of dicarboxylic acid components (comonomer components) other than terephthalic acid and its ester-forming derivatives include C8-14 aromatic dicarboxylic acids such as isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, and 4,4'-dicarboxydiphenyl ether; C4-16 alkanedicarboxylic acids such as succinic acid, adipic acid, azelaic acid, and sebacic acid; C5-10 cycloalkanedicarboxylic acids such as cyclohexanedicarboxylic acid; and ester-forming derivatives of these dicarboxylic acid components (C1-6 alkyl ester derivatives, acid halides, etc.). These dicarboxylic acid components can be used alone or in combination of two or more.

[0023] Among these dicarboxylic acid components, C8-12 aromatic dicarboxylic acids such as isophthalic acid, and C6-12 alkanedicarboxylic acids such as adipic acid, azelaic acid, and sebacic acid are more preferred.

[0024] In the PBT resin (A), examples of glycol components (comonomer components) other than 1,4-butanediol include 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 2-mol ethylene oxide adducts of bisphenol A and 3-mol propylene oxide adducts of bisphenol A; and ester-forming derivatives of these glycols (acetylated products, etc.). These glycol components can be used alone or in combination of two or more.

[0025] Among these glycol components, C2-6 alkylene glycols such as ethylene glycol and trimethylene glycol, polyoxyalkylene glycols such as diethylene glycol, and alicyclic diols such as cyclohexanedimethanol are more preferred. Examples of comonomer components that can be used in addition to the dicarboxylic acid component and the glycol component include 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; C3-12 lactones such as propiolactone, butyrolactone, valerolactone, and caprolactone (ε-caprolactone, etc.); and ester-forming derivatives of these comonomer components (C1-6 alkyl ester derivatives, acid halides, acetylated products, etc.).

[0026] Any of the polybutylene terephthalate copolymers obtained by copolymerizing the comonomer components described above can be suitably used as the PBT resin (A). In addition, a homopolybutylene terephthalate polymer and a polybutylene terephthalate copolymer may be used in combination as the PBT resin (A).

[0027] If the intrinsic viscosity and amount of carboxylic acid end groups of PBT resin (A) are within the above-mentioned ranges, market recovered products can be used (material recycling). In addition, PBT resins produced by decomposing 1,4-butanediol, terephthalic acid, etc. from PBT resin waste to the monomer level (chemical recycling) and polycondensing the obtained raw materials can also be used. The form of the manufacturing method using such PBT resins will be described later.

[0028] [Brominated flame retardants (B)] In the PBT resin composition of the present embodiment, the brominated flame retardant (B) includes a brominated epoxy flame retardant and / or a brominated acrylate flame retardant. By including the brominated flame retardant (B), it is possible to impart flame retardancy to the PBT resin composition without reducing hydrolysis resistance.

[0029] (Brominated epoxy flame retardant) As the brominated epoxy flame retardant, for example, an aromatic epoxy compound containing one or more epoxy groups in one molecule (such as a biphenyl type epoxy compound, a bisphenol A type epoxy compound, a phenol novolac type epoxy compound, or a cresol novolac type epoxy compound) can be used.

[0030] The number average molecular weight of the brominated epoxy flame retardant is preferably 13,000 or more. As the brominated epoxy flame retardant, for example, one having a number average molecular weight of 13,000 or more and 20,000 or less can be preferably used. From the viewpoint of moldability of the PBT resin composition, the number average molecular weight of the brominated epoxy flame retardant is more preferably 14,000 or more and 18,000 or less, and further preferably 15,000 or more and 16,000 or less. The number average molecular weight of the brominated epoxy flame retardant can be determined in terms of polystyrene by gel permeation chromatography (GPC).

[0031] The epoxy equivalent of the brominated epoxy flame retardant is preferably 20,000 g / eq or more, more preferably 30,000 g / eq or more, and even more preferably 31,000 g / eq or more. By setting the epoxy equivalent within this range, the PBT resin composition of the present embodiment tends to be more effectively prevented from adhering to the screw of an extruder or molding machine during molding of the composition.

[0032] In addition, it is preferable to use, as the above-mentioned brominated epoxy flame retardant, one whose ends are blocked with bromophenol (tribromophenol, etc.), since this can suppress the decrease in the fluidity of the PBT resin composition.

[0033] The brominated epoxy flame retardants can be used alone or in combination of two or more.

[0034] (Brominated acrylate flame retardants) The brominated acrylate flame retardant is preferably a polymer. For example, the brominated acrylate flame retardant may be one represented by the following formula (I):

[0035] [ka]

[0036] In formula (I), X each independently represents a hydrogen atom or a substituent, and at least one of X is a bromine atom. Examples of the substituent represented by X include a halogen atom. For example, X may each independently represent a hydrogen atom or a bromine atom. The number of X in one structural unit is 5, and for example, 3 to 5 of them may be a substituent. From the viewpoint of flame retardancy, it is preferable that 3 to 5 of the 5 X in one structural unit are bromine atoms. The average degree of polymerization m is 10 to 2000, and preferably 15 to 1000. When the average degree of polymerization m is 10 or more, the thermal stability tends to be better. On the other hand, when the average degree of polymerization m is 2000 or less, the molding processability of the PBT resin composition to which it is added tends to be better. In addition, the above brominated acrylate flame retardants may be used alone or in combination of two or more.

[0037] The brominated acrylate flame retardant represented by formula (I) can be obtained by polymerizing bromine-containing benzyl acrylate (hereinafter sometimes referred to as "bromine-containing benzyl acrylate") alone. The brominated acrylate flame retardant may have a structure obtained by copolymerizing, for example, bromine-containing benzyl acrylate with benzyl methacrylate or the like having a similar structure. Examples of bromine-containing benzyl acrylates include pentabromobenzyl acrylate, tetrabromobenzyl acrylate, tribromobenzyl acrylate, and mixtures thereof. Of these, pentabromobenzyl acrylate is preferred. Examples of benzyl methacrylates that can be copolymerized with bromine-containing benzyl acrylate include methacrylates corresponding to the above-mentioned acrylates.Furthermore, copolymerization with vinyl monomers is also possible, and 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.In addition, crosslinkable vinyl monomers, xylylene diacrylate, xylylene dimethacrylate, tetrabromo xylylene diacrylate, tetrabromo xylylene dimethacrylate, butadiene, isoprene, and divinylbenzene can also be used.These are preferably used in an equimolar amount or less, more preferably 0.5 times the molar amount or less, relative to benzyl acrylate or benzyl methacrylate.

[0038] An example of the method for producing the brominated acrylate flame retardant is a method in which a monomer such as bromine-containing benzyl acrylate is reacted to a predetermined degree of polymerization by solution polymerization or bulk polymerization. In the case of solution polymerization, it is preferable not to use a halogenated aromatic compound such as chlorobenzene as a solvent. In addition, as the solvent for solution polymerization, aprotic solvents such as ethylene glycol monomethyl ether, methyl ethyl ketone, ethylene glycol dimethyl ether, and dioxane are preferable.

[0039] The above brominated acrylate flame retardant is preferably washed with an aqueous solution containing water and / or alkaline (earth) metal ions in order to remove reaction by-products such as residual sodium polyacrylate. An aqueous solution containing alkaline (earth) metal ions can be easily obtained by adding an alkaline (earth) metal salt to water, but an alkaline (earth) metal hydroxide (e.g., calcium hydroxide) that does not contain chloride ions, phosphate ions, etc. is optimal. When calcium hydroxide is used as the alkaline (earth) metal salt, calcium hydroxide is generally soluble at about 0.126 g in 100 g of water at 20°C, and the aqueous solution concentration is not particularly limited as long as it is up to the solubility. In addition, the method of washing with an aqueous solution containing water and / or alkaline (earth) metal ions is not particularly limited, and a method such as immersing the brominated acrylate flame retardant in an aqueous solution containing water and / or alkaline (earth) metal ions for an appropriate time may be used. The brominated acrylate flame retardant that has been subjected to the above-mentioned washing treatment with water and / or an aqueous solution containing alkaline (earth) metal ions generally has a dry solid content in the hot water extract of 100 ppm or less. When such a brominated acrylate flame retardant is used, there is almost no generation of foreign matter originating from the brominated acrylate flame retardant on the surface of the molded product.

[0040] The brominated acrylate flame retardants can be used alone or in combination of two or more.

[0041] In the PBT resin composition of the present embodiment, the content of bromine atoms derived from the bromine-based flame retardant (B) is preferably 0.13 mol or more per 100 g of PBT resin (A). By making the content of bromine atoms 0.13 mol or more per 100 g of PBT resin (A), the burning time can be reduced, the spread of fire due to dripping (dripping of molten resin) can be prevented, and the flame retardancy can be improved. The content of bromine atoms in the PBT resin composition is preferably 0.14 mol or more per 100 g of PBT resin (A), more preferably 0.15 mol or more, even more preferably 0.16 mol or more, and particularly preferably 0.17 mol or more.

[0042] The upper limit of the bromine atom content in the PBT resin composition is preferably 0.30 mol or less, more preferably 0.28 mol or less, and even more preferably 0.25 mol or less, from the viewpoint of corrosion resistance during molding. In one embodiment, the content of bromine atoms in the PBT resin composition may be 0.13 to 0.30 mol, 0.14 to 0.28 mol, or 0.15 to 0.25 mol. When two or more kinds of brominated flame retardants (B) are used in combination, it is preferable to add each brominated flame retardant (B) so that the total content of bromine atoms in the PBT resin composition falls within the above range.

[0043] [Antimony-based flame retardant synergist (C)] In the PBT resin composition of the present embodiment, the antimony-based flame retardant auxiliary is not particularly limited, but specific examples include antimony trioxide, antimony tetraoxide, antimony pentoxide, sodium antimonate, antimony halides, etc. Among these, it is preferable to use antimony trioxide in terms of supplyability and cost.

[0044] The form of the antimony-based flame retardant auxiliary (C) is not particularly limited, but is preferably particulate with an average particle size of 0.1 to 10 μm, more preferably 0.3 to 5 μm, and even more preferably 0.5 to 2 μm. When the average particle size of the antimony-based flame retardant auxiliary is 10 μm or less, the resulting PBT resin composition is less likely to become a starting point of breakage when mechanical stress is applied thereto, is less likely to become brittle, and tends not to have a reduced flame retardancy. The average particle size can be measured using a laser diffraction / scattering type particle size distribution measuring device LA-920 (manufactured by Horiba, Ltd.) using distilled water as a dispersion medium, and can be obtained as a median size.

[0045] The antimony-based flame retardant auxiliary (C) can be used alone or in combination of two or more.

[0046] The content of the antimony-based flame retardant auxiliary (C) in the PBT resin composition is preferably 3 to 10 parts by mass, more preferably 4 to 9 parts by mass, per 100 parts by mass of the PBT resin (A). When the content of the antimony-based flame retardant auxiliary (C) per 100 parts by mass of the PBT resin (A) is 3 parts by mass or more, the effect as a flame retardant auxiliary is more likely to be exhibited. On the other hand, when the content of the antimony-based flame retardant auxiliary (C) per 100 parts by mass of the PBT resin (A) is 10 parts by mass or less, defects such as a decrease in mechanical properties tend not to occur. In addition, in terms of the relationship with the content of the bromine-based flame retardant (B), the total mass of the bromine atoms in the bromine-based flame retardant (B) and the antimony atoms in the antimony-based flame retardant auxiliary (C) in the PBT resin composition may be 15 to 35 mass%, preferably 18 to 33 mass%, more preferably 20 to 30 mass% relative to the total amount of organic components in the PBT resin composition. In addition, the ratio (bromine atom / antimony atom) of the mass of the bromine atoms in the bromine-based flame retardant (B) to the mass of the antimony atoms in the antimony-based flame retardant auxiliary (C) in the PBT resin composition may be 2 / 1 to 4 / 1. By blending the antimony-based flame retardant auxiliary so as to satisfy the above, the flame retardancy imparting effect of the bromine-based flame retardant (B) can be effectively enhanced.

[0047] [Inorganic filler (D)] In the PBT resin composition of the present embodiment, the inorganic filler (D) is surface-treated with a sizing agent containing an epoxy resin and a polymer containing structural units derived from a carboxylic acid and / or a carboxylic acid anhydride. By including the inorganic filler (D), the mechanical strength of the molded product is improved, and further, the surface treatment with a specific sizing agent provides excellent hydrolysis resistance.

[0048] The inorganic filler (D) may be in the form of either a fibrous inorganic filler or a non-fibrous inorganic filler, with a fibrous inorganic filler being preferred.

[0049] (fibrous inorganic filler) Examples of fibrous inorganic fillers include glass fibers, carbon fibers, silica fibers, silica-alumina fibers, zirconia fibers, boron nitride fibers, silicon nitride fibers, boron fibers, potassium titanate fibers, and metal fibers (e.g., stainless steel, aluminum, titanium, copper, brass, etc.). Representative examples of fibrous inorganic fillers include glass fibers and carbon fibers, and glass fibers are preferably used in terms of availability and cost. The type of glass used as the raw material for glass fibers is not particularly limited, but E glass and corrosion-resistant glass containing zirconium elements in the composition are preferably used in terms of quality.

[0050] The average fiber diameter of the fibrous inorganic filler is preferably 3 to 50 μm, more preferably 6 to 15 μm, from the viewpoint of mechanical properties and prevention of gate clogging during injection molding. The average fiber length of the fibrous inorganic filler is not particularly limited, and can be, for example, 0.1 to 20 mm. The average fiber diameter and average fiber length of the fibrous filler are values ​​calculated by analyzing an image taken by a CCD camera of the fibrous filler before it is mixed into the resin composition, and calculating the weighted average. For example, they can be calculated using a dynamic image analysis method / particle (state) analyzer PITA-3 manufactured by Seishin Enterprise Co., Ltd.

[0051] As the fibrous inorganic filler, either one having a circular cross section or one having a noncircular cross section can be used. Examples of noncircular cross sections include oval, elliptical, and cocoon shapes. The irregularity ratio (major axis diameter:minor axis diameter) of the noncircular cross section is not particularly limited, but is preferably 1.5:1 to 6:1, more preferably 2:1 to 5:1, and even more preferably 2.5:1 to 4:1. When the irregularity ratio is in the range of 1.5:1 to 6:1, the effects of dimensional stability and warpage reduction due to the flattening of the cross section can be easily obtained, and the decrease in strength due to the excessive flatness that makes the material more susceptible to cracking can also be easily suppressed.

[0052] (Non-fibrous inorganic filler) The shape of the non-fibrous inorganic filler is not particularly limited, and examples thereof include granular, ellipsoidal, spindle-shaped, plate-shaped, scaly, irregular, etc. Specific examples of the non-fibrous inorganic filler include silicates such as mica, talc, quartz, calcium silicate, aluminum silicate, kaolin, clay, diatomaceous earth, and bentonite; carbon-based materials such as carbon black and graphite; metal carbonates such as calcium carbonate and magnesium carbonate; metal sulfates such as zinc sulfate, calcium sulfate, and barium sulfate; metal oxides such as zinc oxide, iron oxide, titanium oxide, antimony trioxide, and alumina; glass flakes, glass beads, milled glass fibers, glass balloons, glass powder, and the like; and other materials such as magnesium hydroxide, boehmite, spherical silica, ferrite, silicon carbide, silicon nitride, boron nitride, and various metal powders, but are not limited thereto. From the viewpoint of improving low warpage properties, it is preferable to contain a plate-like or scaly inorganic filler such as mica, glass flakes, or talc, and it is more preferable to contain at least a plate-like inorganic filler such as mica or talc.

[0053] The inorganic filler (D) may be used alone or in combination of two or more kinds.

[0054] In addition, a fibrous inorganic filler and a non-fibrous inorganic filler may be used in combination. By using a fibrous inorganic filler and a non-fibrous inorganic filler in combination, it is possible to achieve both low warpage and mechanical properties such as tensile strength. The ratio of the fibrous inorganic filler and the non-fibrous inorganic filler is not particularly limited, but the fibrous inorganic filler / non-fibrous inorganic filler (mass ratio) is preferably 80 / 20 to 45 / 55, more preferably 75 / 25 to 55 / 45, and even more preferably 70 / 30 to 60 / 40. When the content of the non-fibrous inorganic filler is 20% by mass or more of the inorganic filler, better low warpage is easily obtained, and when it is 55% by mass or less, better tensile strength is easily obtained. The combination of the fibrous inorganic filler and the non-fibrous inorganic filler is not particularly limited, but examples thereof include a combination of a fibrous inorganic filler such as glass fiber or carbon fiber with a non-fibrous inorganic filler such as glass flake, mica or talc, and it is preferable that the combination contains at least glass fiber and mica.

[0055] Next, the polymer having a structural unit derived from a carboxylic acid and / or a carboxylic acid anhydride and the epoxy resin contained in the sizing agent used in the surface treatment of the inorganic filler (D) will be described below.

[0056] (Polymers Having Structural Units Derived from Carboxylic Acids and / or Carboxylic Acid Anhydrides) In the polymer having a structural unit derived from a carboxylic acid and / or a carboxylic acid anhydride (hereinafter, simply referred to as a "polymer"), the carboxylic acid may be an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, fumaric acid, maleic acid, succinic acid, cinnamic acid, itaconic acid, mesaconic acid, citraconic acid, etc. These may have a substituent. Among them, acrylic acid, methacrylic acid, and maleic acid are preferable. In addition, the carboxylic acid anhydride may be an anhydride of an unsaturated carboxylic acid such as maleic anhydride, itaconic anhydride, succinic anhydride, phthalic anhydride, glutaric anhydride, dodecenylsuccinic anhydride, or chlorendic anhydride. The above polymers may be homopolymers in which each carboxylic acid or carboxylic anhydride is polymerized alone, or may be copolymers in which two or more carboxylic acids or carboxylic anhydrides are copolymerized.

[0057] In this embodiment, the weight average molecular weight of the above polymer is not particularly limited, but is particularly preferably 10,000 to 1,000,000. When the weight average molecular weight is within the range of 10,000 to 1,000,000, sufficient hydrolysis resistance is obtained and sufficient adhesion to the surface of the inorganic filler is achieved.

[0058] (Epoxy resin) Examples of epoxy resins include glycidyl ether type epoxy resins, glycidyl ester type epoxy resins (diglycidyl phthalate, diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, dimethylglycidyl phthalate, dimethylglycidyl hexahydrophthalate, dimer acid glycidyl ester, aromatic diglycidyl ester, cycloaliphatic diglycidyl ester, etc.), glycidyl amine type epoxy resins (tetraglycidyldiaminodiphenylmethane, triglycidyl-paraaminophenol, triglycidyl-methamine, etc.), and the like. nonphenol, diglycidyl toluidine, tetraglycidyl metaxylylenediamine, diglycidyl tribromoaniline, tetraglycidyl bisaminomethylcyclohexane, etc.), heterocyclic epoxy resins (triglycidyl isocyanurate (TGIC), hydantoin type epoxy resins, etc.), cyclic aliphatic epoxy resins (vinylcyclohexene dioxide, dicyclopentadiene oxide, alicyclic diepoxy acetal, alicyclic diepoxy adipate, alicyclic diepoxy carboxylate, etc.), epoxidized polybutadiene, etc.

[0059] Glycidyl ether type epoxy resins include glycidyl ethers of polyhydroxy compounds [glycidyl ethers of aromatic polyhydroxy compounds such as bisphenol type epoxy resins (e.g., bisphenol A type, bisphenol AD ​​type, or bisphenol F type epoxy resins), and resorcin type epoxy resins; aliphatic epoxy resins (glycidyl ethers of alkylene glycols, polyoxyalkylene glycols, and the like)], novolac type epoxy resins (phenol novolac type, cresol novolac type epoxy resins, and the like), and the like.

[0060] Among epoxy resins, aromatic epoxy resins (such as bisphenol-type epoxy resins, resorcin-type epoxy resins, and phenol novolac-type epoxy resins) and cyclic aliphatic epoxy resins are preferred. Among them, glycidyl ether-type aromatic epoxy resins, such as bisphenol-type epoxy resins and phenol novolac-type epoxy resins, are preferred.

[0061] The epoxy equivalent of the epoxy resin may be, for example, about 100 to 1600 g / eq, preferably about 100 to 800 g / eq, and more preferably about 150 to 500 g / eq.

[0062] The number average molecular weight of the epoxy resin may be, for example, about 200 to 50,000, preferably about 300 to 10,000, and more preferably about 400 to 6,000.

[0063] In this embodiment, the mass ratio (X / Y) of the polymer (X) to the epoxy resin (Y) in the sizing agent is preferably 0.001 to 1.500 from the viewpoint of improving the mechanical strength of the molded product.

[0064] The sizing agent is preferably contained in an amount of 0.1 to 3.0 parts by mass, and more preferably 0.3 to 2.5 parts by mass, per 100 parts by mass of the inorganic filler (D). By containing the sizing agent in an amount of 0.1 to 3.0 parts by mass, hydrolysis resistance can be improved.

[0065] In addition to the above components, the bundling agent may contain components such as urethane resin, silane coupling agent, lubricant, nonionic surfactant, antistatic agent, etc., and the mixing ratio of each component may be determined as necessary. The urethane resin contributes to the bundling and dispersibility of the glass fiber, and is obtained from polyisocyanate and polyol, etc. As the silane coupling agent, aminosilane, epoxysilane, chlorosilane, mercaptosilane, vinylsilane, acrylicsilane, etc. can be used. As the lubricant, fatty acid amide, quaternary ammonium salt, etc. can be used. As the nonionic surfactant, synthetic alcohol, natural alcohol, fatty acid ester, etc. can be used.

[0066] In the PBT resin composition of this embodiment, the inorganic filler (D) is contained in an amount of 10 to 100 parts by mass, preferably 20 to 80 parts by mass, and more preferably 30 to 70 parts by mass, per 100 parts by mass of the PBT resin (A). If the content of the inorganic filler (C) is less than 10 parts by mass, the effect of improving mechanical strength cannot be obtained, and if it exceeds 100 parts by mass, the toughness decreases, and breakage from the welds and a decrease in strength after wet heat treatment become noticeable.

[0067] [Anti-drip agent] In order to prevent the spread of fire due to dripping of burning resin, it is also preferable to use a drip prevention agent such as polytetrafluoroethylene in the PBT resin composition. The drip prevention agent may be used alone or in combination of two or more.

[0068] [Hydrolysis resistance improver] In the PBT resin composition of the present embodiment, in order to further improve the hydrolysis resistance, it is preferable to contain 0.5 to 3.0 parts by mass of an aromatic carbodiimide and / or an epoxy compound as a hydrolysis resistance improver (D).

[0069] [Aromatic carbodiimide compounds] The aromatic carbodiimide compound is a compound having a carbodiimide group (-N=C=N-) in the molecule and an aromatic main chain. Among the carbodiimide compounds, the aromatic carbodiimide compound is preferable in terms of excellent heat resistance and moist heat resistance.

[0070] Examples of the aromatic carbodiimide compound 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-fluorophenylcarbodiimide, mono- or dicarbodiimide compounds such as p-phenylene-bis-di-o-triylcarbodiimide, p-phenylene-bis-dicyclohexylcarbodiimide, p-phenylene-bis-di-p-chlorophenylcarbodiimide, and ethylene-bis-diphenylcarbodiimide; and poly(4,4'-diphenylmethanecarbodiimide), poly(3,5'-dimethyl-4,4'-biphenylmethanecarbodiimide), poly(p-phenylenecarbodiimide), poly(m-phenylenecarbodiimide), poly(3,5'-dimethyl-4,4'-diphenyl Examples of the polycarbodiimide compounds include poly(1,3-diisopropylphenylenecarbodiimide), poly(naphthylenecarbodiimide), poly(1,3-diisopropylphenylenecarbodiimide), poly(1-methyl-3,5-diisopropylphenylenecarbodiimide), poly(1,3,5-triethylphenylenecarbodiimide) and poly(triisopropylphenylenecarbodiimide). Two or more of these may be used in combination.

[0071] The number average molecular weight of the aromatic carbodiimide compound is preferably at least 3000. By setting the number average molecular weight within the above range, it is possible to prevent the generation of gas or odor when the residence time is long during melt-kneading or molding of the thermoplastic resin.

[0072] The content of the aromatic carbodiimide compound is preferably 0.5 to 3.0 parts by mass relative to 100 parts by mass of the PBT resin (A). When the content is 0.5 parts by mass or more, the hydrolysis resistance can be improved, and when the content is 3.0 parts by mass or less, the decrease in fluidity is suppressed and the generation of gel components or charred materials during compounding (when producing the resin composition) or molding is suppressed.

[0073] [Epoxy compounds] Examples of the epoxy compound in this embodiment include 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. The epoxy compound may be used in any combination of two or more compounds. The epoxy equivalent is preferably 600 to 1500 g / equivalent (g / eq).

[0074] In this embodiment, the epoxy compound is preferably added in an amount of 0.5 to 3.0 parts by mass relative to 100 parts by mass of the PBT resin (A). When the content is 0.5 parts by mass or more, hydrolysis resistance can be improved, and when the content is 5 parts by mass or less, the generation of char during molding is suppressed, and unfilled areas and discoloration due to increased viscosity can be suppressed.

[0075] [Other ingredients] The PBT resin composition of the present embodiment may contain other components as necessary. Examples of other components include, but are not limited to, inorganic fillers other than the inorganic filler (D), antioxidants, weather stabilizers, molecular weight regulators, ultraviolet absorbers, antistatic agents, dyes, pigments, lubricants, crystallization accelerators, crystal nucleating agents, near-infrared absorbers, organic fillers, and colorants.

[0076] <Resin molded products> The resin molded article of the present embodiment is produced by molding the PBT resin composition of the present embodiment described above, and therefore has the effect of having flame retardancy similar to that of the PBT resin composition of the present embodiment, and of having significantly improved hydrolysis resistance compared to conventional compositions.

[0077] The method for producing a resin molded article using the PBT resin composition of the present embodiment is not particularly limited, and a known method can be adopted. For example, the PBT resin composition of the present embodiment can be put into an extruder, melt-kneaded and pelletized, and the pellets can be put into an injection molding machine equipped with a predetermined mold and injection molded to produce the resin molded article.

[0078] The resin molded article of the present embodiment can be suitably used as a resin composition for molded articles that require flame retardancy in the applications of automobile parts and electric / electronic parts. The molded article made of this resin composition can be used for relays, switches, transformer bobbins, terminal blocks, covers, switches, sockets, coils, plug connectors, etc. because it can prevent degradation due to hydrolysis even when used for a long period of time under a sufficiently high temperature and high humidity environment.

[0079] <Method of producing polybutylene terephthalate resin composition> There are two methods for producing the PBT resin composition of the present embodiment, a first method and a second method, and either method is one method for producing the PBT resin composition of the present embodiment described above. In the first embodiment, the method includes a step A of obtaining a polybutylene terephthalate resin (A) having an intrinsic viscosity of 0.70 dL / g or more and 1.10 dL / g or less and a carboxylic acid end group amount of 18 meq / kg or less using 1,4-butanediol and / or terephthalic acid obtained by chemical recycling, and a step B of mixing the polybutylene terephthalate resin (A), a brominated flame retardant (B), an antimony-based flame retardant auxiliary (C), and an inorganic filler (D) surface-treated with a sizing agent containing a polymer containing a structural unit derived from a carboxylic acid and / or a carboxylic acid anhydride and an epoxy resin. The brominated flame retardant (B) contains a brominated epoxy flame retardant and / or a brominated acrylate flame retardant. In the step B, 10 to 100 parts by mass of the inorganic filler (D) is mixed with 100 parts by mass of the polybutylene terephthalate resin (A).

[0080] In the second embodiment, the method includes a step of obtaining a polybutylene terephthalate resin (A) having an intrinsic viscosity of 0.70 dL / g or more and 1.10 dL / g or less and a carboxylic acid end group amount of 18 meq / kg or less by material recycling, and a step B of mixing the polybutylene terephthalate resin (A), a brominated flame retardant (B), an antimony-based flame retardant auxiliary (C), and an inorganic filler (D) surface-treated with a sizing agent containing a polymer containing a structural unit derived from a carboxylic acid and / or a carboxylic acid anhydride and an epoxy resin. The brominated flame retardant (B) contains a brominated epoxy flame retardant and / or a brominated acrylate flame retardant. In the step B, 10 to 100 parts by mass of the inorganic filler (D) is mixed with 100 parts by mass of the polybutylene terephthalate resin (A).

[0081] In the above-mentioned first and second embodiments, the PBT resin (A) is obtained by utilizing chemical recycling and material recycling, respectively, but the production of the PBT resin composition of the above-mentioned embodiment is not limited to the production methods according to the first and second embodiments. That is, as long as a PBT resin having an intrinsic viscosity of 0.70 dL / g or more and 1.10 dL / g or less and a carboxylic acid terminal group amount of 18 meq / kg or less can be obtained, there is no limitation on the method for obtaining the PBT resin (A).

[0082] The first and second forms are different in the process of obtaining the PBT resin (A). That is, in the first form, the PBT resin (A) is obtained using 1,4-butanediol and / or terephthalic acid obtained by chemical recycling, whereas in the second form, the PBT resin (A) is obtained by material recycling.

[0083] In both the first and second forms, PBT resin, which is waste plastic, can be reused, which contributes to saving natural resources and reducing the environmental burden.

[0084] In the first form, PBT resin (A) is produced by decomposing 1,4-butanediol, terephthalic acid, etc. from PBT resin waste etc. to the monomer level (chemical recycling) and polycondensing the obtained raw material. In chemical recycling, PBT resin and alcohols are filled into a reaction vessel and heated to depolymerize the alcohols under supercritical conditions, and 1,4-butanediol and terephthalic acid can be recovered.

[0085] In the second embodiment, the PBT resin (A) is obtained by material recycling. That is, as long as the intrinsic viscosity and the amount of carboxylic acid end groups are within the above-mentioned ranges, market-recovered products can be used. Market-recovered products can be pulverized using a pulverizer such as a single-screw pulverizer, a twin-screw pulverizer, a triple-screw pulverizer, or a cutter mill, and then used. The pulverized products can also be melt-kneaded using a single-screw extruder or a twin-screw extruder, and granulated to be used as pellets. In addition, a stainless steel filter can be set on the breaker plate during melt-kneading to remove foreign matter. Since foreign matter is the starting point of destruction, removing the foreign matter can maintain the mechanical properties and improve the appearance of the molded product made of the PBT resin composition.

[0086] In any embodiment, there is no particular limitation on the manufacturing method as long as the step of obtaining PBT resin (A) can obtain a PBT resin having an intrinsic viscosity of 0.70 dL / g or more and 1.10 dL / g or less and a carboxylic acid terminal group amount of 18 meq / kg or less.

[0087] In the step of mixing the components (A) to (D), the method for mixing the components is not particularly limited, and any known method can be used. For example, the components are fed into an extruder, melt-kneaded, and pelletized. EXAMPLES

[0088] The present embodiment will be described in more detail below with reference to examples, but the present embodiment is not limited to the following examples.

[0089] [Examples 1 to 8, Comparative Examples 1 to 7] In each of the Examples and Comparative Examples, components (A) to (D) were melt-mixed and extruded in the ratios (parts by mass) shown in Tables 2 to 3 using a 30 mmφ twin-screw extruder (TEX30C, manufactured by The Japan Steel Works, Ltd.) with a cylinder temperature of 260°C at the raw material supply section and die tip, and 220 to 260°C between them, at a discharge rate of 15 kg / h and a screw rotation speed of 130 rpm, to obtain pellets made of a PBT resin composition. Details of each component shown in Tables 2 to 3 are shown below.

[0090] (1) PBT resin (A); (A-1): Polyplastics Co., Ltd., PBT resin, intrinsic viscosity: 0.86 dL / g, carboxylic acid end group amount: 12 meq / kg (A-2): PBT resin polycondensed with biomass-derived 1,4-butanediol and terephthalic acid, and titanium tetrabutoxide as a catalyst. Intrinsic viscosity: 0.86 dL / g, carboxylic acid end group amount: 12 meq / kg (A-3): Polyplastics Co., Ltd.'s Duranex 500FP was dried at 140°C for 3 hours, and then a 1A type ISO test piece (width 10 mm, thickness 4 mmt) conforming to ISO3167 was produced using a FANUC Corporation's injection molding machine "ROBOSHOT S-2000i 100B" at a cylinder temperature of 260°C and a mold temperature of 80°C, and the resulting ISO test piece was crushed in a small crusher to produce a PBT resin. Intrinsic viscosity: 0.89 dL / g, carboxylic acid end group amount: 15 meq / kg. (A-4): Polyplastics Co., Ltd., PBT resin, intrinsic viscosity: 0.86 dL / g, carboxylic acid end group amount: 20 meq / kg (A-5): Polyplastics Co., Ltd., PBT resin, intrinsic viscosity: 0.69 dL / g, carboxylic acid end group amount: 24 meq / kg

[0091] (2) Flame retardant (B); (B-1) Brominated flame retardant: Brominated epoxy flame retardant "CXB-1500C" (number average molecular weight: 15,000, epoxy equivalent: 31,000 g / eq), manufactured by Wooshin Polymer Co., Ltd. (B-2) Brominated flame retardant: Brominated epoxy flame retardant "SRT5000S" (number average molecular weight: 10000, epoxy equivalent: 5000g / eq), manufactured by Sakamoto Pharmaceutical Co., Ltd. (B-3) Brominated flame retardant: Brominated benzyl acrylate flame retardant "FR-1025" manufactured by ICL Japan Co., Ltd. (B-4) Phosphorus-based flame retardant: aluminum diethylphosphinate EXOLIT OP1240, manufactured by Clariant Japan Ltd.

[0092] (3) flame retardant synergist (C); (C-1) Antimony-based flame retardant assistant: Antimony trioxide, manufactured by Nihon Seiko Co., Ltd. (C-2) Antimony-based flame retardant assistant: Antimony pentoxide, HY1030, manufactured by Yamanaka Sangyo Co., Ltd. (C-3) Nitrogen-based flame retardant synergist: Melamine cyanurate MELAPUR MC50, manufactured by BASF Japan Ltd.

[0093] (4) Inorganic filler (D); (D-1) Glass fiber: E-glass glass fiber, average fiber diameter: 13 μm (bundling agent: 0.5 mass% phenol novolac resin, 0.2 mass% copolymer of maleic anhydride, methyl methacrylate and methyl acrylate) (D-2) Glass fiber: E-glass glass fiber, average fiber diameter: 13 μm (bundling agent: phenol novolac resin 0.5% by mass) (D-3) Glass fiber: E-glass glass fiber, average fiber diameter: 13 μm (bundling agent: copolymer of maleic anhydride, methyl methacrylate and methyl acrylate (0.2 mass%)

[0094] Meanwhile, the components of the sizing agent used in the surface treatment of the glass fibers (D-1) to (D-3) are shown in Table 1. The values ​​in Table 1 indicate the content (mass%) of each component relative to the entire glass fiber. In the glass fiber (D-1), the sizing agent was contained in an amount of 0.7 parts by mass relative to 100 parts by mass of the glass fiber (D-1).

[0095] [Table 1]

[0096] (5) Anti-drip agent Daikin Industries, Ltd.'s "Polyflon PTFE M-392" (polytetrafluoroethylene resin) (6) Epoxy compound: Epicoat 1004, manufactured by Mitsubishi Chemical Corporation (7) Aromatic carbodiimide compound: Stabaxol P-100, aromatic polycarbodiimide, manufactured by LANXESS

[0097] [evaluation] The pellets obtained in each of the Examples and Comparative Examples were used to carry out the following evaluation tests. (1) Flame retardancy Pellets made with the compositions in Tables 2 and 3 were dried at 140°C for 3 hours, then injection molded at a cylinder temperature of 260°C and a mold temperature of 80°C to prepare rectangular test pieces measuring 125mm x 13mm x 1 / 16 inch thick in accordance with UL94, and their flammability was evaluated. Those that met V-0 were rated as V-0, and those that did not were rated as failing. The evaluation results are shown in Tables 2 and 3.

[0098] (2) Hydrolysis resistance Pellets prepared with the compositions shown in Tables 2 and 3 were dried at 140°C for 3 hours, and then injection molded at a cylinder temperature of 260°C and a mold temperature of 80°C to prepare 1A type tensile test specimens in accordance with ISO3167. The tensile strength of the obtained test specimens was measured in accordance with ISO527-1,2. The measurement results are shown in Tables 2 and 3. Next, using a PCT processing device (highly accelerated life test device), the test specimens were exposed to 121°C and 100% RH, and the tensile strength was measured after the moist heat test (50 hours and 100 hours), and the strength retention rate before and after the moist heat treatment was calculated. The calculation results are shown in Tables 2 and 3.

[0099] [Table 2]

[0100] [Table 3]

[0101] It can be seen from Tables 2 and 3 that good evaluation results were obtained for both flame retardancy and hydrolysis resistance in Examples 1 to 7. That is, it was demonstrated that Examples 1 to 7 produced resin molded articles having excellent flame retardancy and hydrolysis resistance. On the other hand, Comparative Example 1, which differs from Example 1 only in that it used glass fiber (D-2) surface-treated with a sizing agent containing only an epoxy resin, had poor hydrolysis resistance. Similarly, Comparative Example 2, which differs from Example 1 only in that it used glass fiber (D-3) surface-treated with a sizing agent containing only a copolymer of maleic anhydride, methyl methacrylate, and methyl acrylate, had poor hydrolysis resistance. Comparative Example 3, which differs from Example 4 only in that it used glass fiber (D-2) surface-treated with a sizing agent containing only an epoxy resin, had poor hydrolysis resistance. Similarly, Comparative Example 4, which differs from Example 4 only in that it used glass fiber (D-3) surface-treated with a sizing agent containing only a copolymer of maleic anhydride, methyl methacrylate, and methyl acrylate, had poor hydrolysis resistance. In addition, Comparative Example 5, which differs from Example 1 only in that a PBT resin (A-4) with a high terminal carboxyl group was used, and Comparative Example 6, which differs from Example 1 only in that a PBT resin (A-5) with a low intrinsic viscosity and a high terminal carboxyl group was used, had poor hydrolysis resistance. Moreover, Comparative Example 7, which did not contain the antimony-based flame retardant auxiliary (C), had poor flame retardancy. Furthermore, Comparative Examples 8 and 9, in which a phosphorus-based flame retardant was used as the flame retardant and a nitrogen-based flame retardant auxiliary was used as the flame retardant auxiliary, had good flame retardancy but poor hydrolysis resistance.

Claims

1. The flame retardant comprises: (A) a polybutylene terephthalate resin having an intrinsic viscosity of 0.70 dL / g or more and 1.10 dL / g or less and a carboxylic acid terminal group amount of 18 meq / kg or less; (B) a bromine-based flame retardant; (C) an antimony-based flame retardant auxiliary; and (D) an inorganic filler surface-treated with a sizing agent containing an epoxy resin and a polymer containing structural units derived from a carboxylic acid and / or a carboxylic acid anhydride; the brominated flame retardant (B) comprises a brominated epoxy flame retardant and / or a brominated acrylate flame retardant, the polymer containing a structural unit derived from a carboxylic acid and / or a carboxylic acid anhydride includes a copolymer of maleic anhydride, methyl methacrylate, and methyl acrylate; A polybutylene terephthalate resin composition comprising 10 to 100 parts by mass of the inorganic filler (D) per 100 parts by mass of the polybutylene terephthalate resin (A).

2. The polybutylene terephthalate resin composition according to claim 1, further comprising 0.5 to 3.0 parts by mass of an aromatic carbodiimide and / or an epoxy compound per 100 parts by mass of the polybutylene terephthalate resin (A).

3. 3. The polybutylene terephthalate resin composition according to claim 1, wherein the inorganic filler (D) is fibrous and has an average fiber diameter of 3 to 50 μm, and the content of the sizing agent is 0.1 to 3.0 parts by mass per 100 parts by mass of the inorganic filler (D).

4. A resin molded article made from the polybutylene terephthalate resin composition according to claim 1 or 2.

5. A method for producing the polybutylene terephthalate resin composition according to claim 1 or 2, A step A of obtaining a polybutylene terephthalate resin (A) having an intrinsic viscosity of 0.70 dL / g or more and 1.10 dL / g or less and a carboxylic acid terminal group amount of 18 meq / kg or less using 1,4-butanediol and / or terephthalic acid obtained by chemical recycling; and and step B of mixing the polybutylene terephthalate resin (A), a bromine-based flame retardant (B), an antimony-based flame retardant auxiliary (C), and an inorganic filler (D) surface-treated with a sizing agent containing a polymer including a structural unit derived from a carboxylic acid and / or a carboxylic acid anhydride and an epoxy resin, the brominated flame retardant (B) comprises a brominated epoxy flame retardant and / or a brominated acrylate flame retardant, the polymer containing a structural unit derived from a carboxylic acid and / or a carboxylic acid anhydride includes a copolymer of maleic anhydride, methyl methacrylate, and methyl acrylate; In the step B, 10 to 100 parts by mass of the inorganic filler (D) is mixed with 100 parts by mass of the polybutylene terephthalate resin (A).

6. A method for producing the polybutylene terephthalate resin composition according to claim 1 or 2, A step of obtaining a polybutylene terephthalate resin (A) obtained by material recycling, which has an intrinsic viscosity of 0.70 dL / g or more and 1.10 dL / g or less and a carboxylic acid terminal group amount of 18 meq / kg or less; and step B of mixing the polybutylene terephthalate resin (A), a bromine-based flame retardant (B), an antimony-based flame retardant auxiliary (C), and an inorganic filler (D) surface-treated with a sizing agent containing a polymer including a structural unit derived from a carboxylic acid and / or a carboxylic acid anhydride and an epoxy resin, the polymer containing a structural unit derived from a carboxylic acid and / or a carboxylic acid anhydride includes a copolymer of maleic anhydride, methyl methacrylate, and methyl acrylate; the brominated flame retardant (B) comprises a brominated epoxy flame retardant and / or a brominated acrylate flame retardant, In the step B, 10 to 100 parts by mass of the inorganic filler (D) is mixed with 100 parts by mass of the polybutylene terephthalate resin (A).