Flame-retardant polybutylene terephthalate resin composition

Abstract

To inhibit corrosion of a metal member to be in contact with a molding composed of a polybutylene terephthalate resin composition using a halogenated benzyl acrylate flame retardant as a flame retardant, and improve hydrolysis resistance of the molding.SOLUTION: The problem is solved by reducing the amount of a halogenated aromatic compound such as chlorobenzene derived from a halogenated benzyl acrylate flame retardant used as a flame retardant, in a polybutylene terephthalate resin composition to which a hydrolysis resistance improver and a flame retardant area added.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a flame-retardant polybutylene terephthalate resin composition and a method for producing the same. [Background technology]

[0002] Polybutylene terephthalate resin (PBT resin) is excellent in various properties such as mechanical properties, electrical properties, and heat resistance, and is therefore widely used as an engineering plastic for various applications such as automobile parts and electrical and electronic equipment parts. Among these, in electrical and electronic equipment part applications, flame retardancy is required for the materials used to prevent ignition due to tracking, etc. Polybutylene terephthalate resin is used as a flame-retardant resin composition with the addition of a flame retardant, since it does not have sufficient flame retardancy by itself.

[0003] One type of flame retardant that can be added to such polybutylene terephthalate resin is a halogenated benzyl acrylate flame retardant, an example of which is polypentabromobenzyl acrylate (PBBPA) as introduced in Patent Document 1. Paragraph 0004 of Patent Document 1 gives examples of methods for producing this flame retardant, including a method of polymerizing the monomer pentabromobenzyl acrylate in ethylene glycol monomethyl ether, methyl ethyl ketone, or ethylene glycol dimethyl ether, and a method of polymerizing it in chlorobenzene.

[0004] Among these, when chlorobenzene, a halogenated aromatic compound, is used as a solvent for polymerization, a small amount of chlorobenzene will be present as an impurity in the final PBBPA. And the polybutylene terephthalate resin composition flame-retarded by adding this will also contain chlorobenzene.

[0005] Although this chlorobenzene is generally a stable compound, in a high temperature environment, especially when it comes into contact with metals such as metal oxides and alkali metal compounds, it may be dechlorinated and generate compounds such as hydrogen chloride. Therefore, when a composition containing this is used in a molded product that comes into contact with a metal member, such as insert molding or terminal press-in, a problem such as corrosion of the metal member may occur. Here, in the above-mentioned electric and electronic component applications, since a molded product made of a polybutylene terephthalate resin composition is used as an electric insulating member in combination with a metal member that is a conductive part, it is required that the metal member is not corroded. In addition, it is required to suppress this not only when the molded product is used in combination with a metal member, but also from the viewpoint of corrosion of metal members such as the screw and cylinder of the molding machine or the mold in the process of molding the molded product itself.

[0006] However, since polybutylene terephthalate resin is a polyester resin, it also has the disadvantage that its physical properties are easily deteriorated due to hydrolysis. Therefore, when a molded article made of a polybutylene terephthalate resin composition used in combination with the above-mentioned metal member is exposed to a humid and hot environment, the molded article is easily broken due to the deterioration of physical properties due to hydrolysis and the distortion caused by heat due to the difference in linear expansion coefficient between metal and resin. Therefore, as a technology for improving the hydrolysis resistance of polybutylene terephthalate resin, Patent Document 2 discloses a polybutylene terephthalate resin composition in which an acrylic core-shell polymer, an epoxy compound, and an aromatic carbodiimide compound are added to polybutylene terephthalate resin. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Special Publication No. 2015-532350 [Patent Document 2] JP 2006-104363 A Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention aims to suppress the deterioration of physical properties due to hydrolysis when a molded article made of a polybutylene terephthalate resin composition using a halogenated benzyl acrylate-based flame retardant as a flame retardant is used in a humid and hot environment, and to suppress corrosion of metal members in contact with the molded article. [Means for solving the problem]

[0009] In the course of research aimed at achieving the above-mentioned object, the present inventors discovered that the above-mentioned object can be achieved by using a halogenated benzyl acrylate flame retardant as a flame retardant in a polybutylene terephthalate resin composition containing a specific hydrolysis resistance improver, and by reducing the amount of halogenated aromatic compounds such as chlorobenzene contained in the polybutylene terephthalate resin composition, in particular by reducing the amount of halogenated aromatic compounds derived from the production process of the flame retardant, thereby completing the present invention.

[0010] That is, the present invention relates to the following (1) to (8). (1) A flame-retardant polybutylene terephthalate resin composition comprising (A) 100 parts by mass of a polybutylene terephthalate resin, (B) 3 to 50 parts by mass of a halogenated benzyl acrylate flame retardant, and (C) 0.1 to 10 parts by mass of a hydrolysis resistance improver, wherein the content of halogenated aromatic compounds other than the flame retardant is less than 0.5 ppm as measured by headspace gas chromatography (heated at 150°C for 1 hour), and wherein the hydrolysis resistance improver contains one or more compounds selected from a carbodiimide compound, an epoxy compound, an oxazoline compound, an oxazine compound, and a combination thereof. (2) The flame-retardant polybutylene terephthalate resin composition according to (1), wherein the halogenated benzyl acrylate flame retardant (B) contains a brominated acrylic polymer represented by general formula (I): [ka] (In the formula, X is a hydrogen atom or a bromine atom, at least one X is a bromine atom, and m is a number from 10 to 2000.) (3) The flame-retardant polybutylene terephthalate resin composition according to (1) or (2), wherein the halogenated benzyl acrylate flame retardant (B) contains polypentabromobenzyl acrylate. (4) The flame-retardant polybutylene terephthalate resin composition according to any one of (1) to (3), wherein the halogenated aromatic compound other than the flame retardant contains a halogenated benzene. (5) The flame-retardant polybutylene terephthalate resin composition according to any one of (1) to (4), wherein the halogenated aromatic compound other than the flame retardant contains chlorobenzene. (6) A method for producing the flame-retardant polybutylene terephthalate resin composition according to any one of (1) to (5), comprising a step of producing a halogenated benzyl acrylate-based flame retardant (B), wherein a solvent having a halogenated aromatic compound content of 1000 ppm or less is used in the step. (7) (B) The method according to (6), wherein no halogenated aromatic compound is used as a solvent in the production process of the halogenated benzyl acrylate flame retardant. (8) (B) The method for producing the halogenated benzyl acrylate flame retardant according to (6) or (7), wherein one or more solvents selected from the group consisting of ethylene glycol monomethyl ether, methyl ethyl ketone, ethylene glycol dimethyl ether and dioxane are used as the solvent in the production process of the halogenated benzyl acrylate flame retardant. (8) The method according to any one of (6) to (8), further comprising a vacuum drying step. Effect of the Invention

[0011] According to the present invention, in a polybutylene terephthalate resin composition that uses a halogenated benzyl acrylate-based flame retardant as a flame retardant, the amount of halogenated aromatic compounds such as chlorobenzene in the production process of the flame retardant is reduced, thereby making it possible to suppress corrosion of metal parts that are combined with a molded article that uses the polybutylene terephthalate resin composition and to suppress deterioration of the physical properties of the molded article due to hydrolysis in a humid and hot environment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] An embodiment of the present invention will be described in detail below. The present invention is not limited to the following embodiment, and can be carried out by making appropriate modifications within the scope that does not impair the effects of the present invention.

[0013] [Flame-retardant polybutylene terephthalate resin composition] Hereinafter, the components of the flame-retardant polybutylene terephthalate resin composition of the present embodiment will be described in detail with reference to examples.

[0014] ((A) Polybutylene terephthalate resin) (A) Polybutylene terephthalate resin (PBT resin) contains at least terephthalic acid or its ester-forming derivative (C 1-6 The polybutylene terephthalate resin is obtained by polycondensation of a dicarboxylic acid component containing an alkylene glycol having at least 4 carbon atoms (such as an alkyl ester or acid halide of the alkylene glycol) and a glycol component containing an alkylene glycol having at least 4 carbon atoms (such as 1,4-butanediol) or an ester-forming derivative thereof (such as an acetylated product). In this embodiment, the polybutylene terephthalate resin (A) is not limited to a homopolybutylene terephthalate resin, and may be a copolymer containing 60 mol % or more of butylene terephthalate units.

[0015] The amount of terminal carboxyl groups in the polybutylene terephthalate resin (A) is not particularly limited as long as it does not impede the object of the present invention, but is preferably 30 meq / kg or less, more preferably 25 meq / kg or less.

[0016] The intrinsic viscosity of the (A) polybutylene terephthalate resin is not particularly limited as long as it does not impede the object of the present invention, but is preferably 0.60 dL / g or more and 1.2 dL / g or less, and more preferably 0.65 dL / g or more and 0.9 dL / g or less. When a polybutylene terephthalate resin having an intrinsic viscosity in such a range is used, the obtained polybutylene terephthalate resin composition has particularly excellent moldability. In addition, the intrinsic viscosity can be adjusted by blending polybutylene terephthalate resins having different intrinsic viscosities. For example, a polybutylene terephthalate resin having an intrinsic viscosity of 1.0 dL / g and a polybutylene terephthalate resin having an intrinsic viscosity of 0.7 dL / g can be blended to prepare a polybutylene terephthalate resin having an intrinsic viscosity of 0.9 dL / g. The intrinsic viscosity of the polybutylene terephthalate resin can be measured, for example, in o-chlorophenol at a temperature of 35°C.

[0017] (A) In the preparation of polybutylene terephthalate resin, when an aromatic dicarboxylic acid other than terephthalic acid or an ester-forming derivative thereof is used as a comonomer component, for example, C 2,4'-dicarboxydiphenyl ether such as isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, and 4,4'-dicarboxydiphenyl ether is used. 8-14 Aromatic dicarboxylic acids; succinic acid, adipic acid, azelaic acid, sebacic acid, etc. 4-16 Alkanedicarboxylic acids such as cyclohexanedicarboxylic acid, etc. 5-10 Cycloalkanedicarboxylic acids; ester-forming derivatives of these dicarboxylic acid moieties (C 1-6 These dicarboxylic acid components can be used alone or in combination of two or more kinds.

[0018] Among these dicarboxylic acid components, C 8-12 Aromatic dicarboxylic acids such as adipic acid, azelaic acid, and sebacic acid 6-12 The alkanedicarboxylic acids of the formula (I) are more preferred.

[0019] (A) In the preparation of polybutylene terephthalate resin, when a glycol component other than 1,4-butanediol is used as a comonomer component, for example, C glycerides such as ethylene glycol, propylene glycol, trimethylene glycol, 1,3-butylene glycol, hexamethylene glycol, neopentyl glycol, and 1,3-octanediol are used. 2-10 alkylene glycols; 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; C diols of bisphenol A such as 2-mol ethylene oxide adduct of bisphenol A and 3-mol propylene oxide adduct of bisphenol A 2-4 or ester-forming derivatives of these glycols (acetylated products, etc.). These glycol components can be used alone or in combination of two or more.

[0020] Among these glycol components, C ethylene glycol, trimethylene glycol, etc. 2-6 More preferred are alkylene glycols such as those mentioned above, polyoxyalkylene glycols such as diethylene glycol, and alicyclic diols such as cyclohexanedimethanol.

[0021] 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; C hydroxycarboxylic acids such as propiolactone, butyrolactone, valerolactone, and caprolactone (ε-caprolactone, etc.); 3-12 Lactones; ester-forming derivatives of these comonomer components (C 1-6 Examples of the alkyl ester derivatives, acid halides, acetylated derivatives, etc. of the above-mentioned compounds include the above-mentioned compounds.

[0022] The content of the (A) polybutylene terephthalate resin is preferably from 10 to 90 mass %, more preferably from 20 to 80 mass %, and further preferably from 30 to 70 mass %, of the total mass of the resin composition.

[0023] ((B) Halogenated benzyl acrylate flame retardants) The halogenated benzyl acrylate flame retardant (B) used in the present invention includes a brominated acrylic polymer represented by the following general formula (I). [ka] In the formula, X is a hydrogen atom or a bromine atom, and at least one is bromine. The number of X is 1 to 5 in one constitutional unit, but the number of bromine atoms is preferably 3 to 5 from the viewpoint of flame retardancy. The average degree of polymerization m is 10 to 2000, preferably 15 to 1000. Those having an average degree of polymerization lower than 10 deteriorate the thermal stability, and those exceeding 2000 deteriorate the moldability of the added polybutylene terephthalate resin. The above brominated acrylic polymers may be used alone or in combination of two or more kinds.

[0024] The halogenated benzyl acrylate flame retardant (B) used in the present invention may contain impurities such as halogenated aromatic compounds derived from the solvent during polymerization or decomposition products of the brominated acrylic polymer, in addition to the above-mentioned brominated acrylic polymer, but the content of such impurities, halogenated aromatic compounds other than the flame retardant, is preferably 100 ppm or less, more preferably 50 ppm or less, even more preferably 30 ppm or less, and particularly preferably 10 ppm or less. The content of halogenated aromatic compounds other than the flame retardant can be determined, for example, by measuring the amount of gas generated by heating a sample of the halogenated benzyl acrylate flame retardant (B) in the headspace using a gas chromatograph, and determining the amount of gas generated by the halogenated aromatic compounds.

[0025] The brominated acrylic polymer represented by the general formula (I) is obtained by polymerizing benzyl acrylate containing bromine alone, but it may be copolymerized with benzyl methacrylate having a similar structure. Examples of the bromine-containing benzyl acrylate include pentabromobenzyl acrylate, tetrabromobenzyl acrylate, tribromobenzyl acrylate, or a mixture thereof. Among them, pentabromobenzyl acrylate is preferable. Examples of the benzyl methacrylate, which is a copolymerizable component, include methacrylates corresponding to the above-mentioned acrylates. Furthermore, copolymerization with vinyl monomers is also possible, and examples of the 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. Also usable are crosslinkable vinyl monomers, xylylene diacrylate, xylylene dimethacrylate, tetrabromo xylylene diacrylate, tetrabromo xylylene dimethacrylate, butadiene, isoprene, and divinylbenzene, which are used in an amount of up to the equimolar amount, preferably up to 0.5 times the molar amount, of benzyl acrylate or benzyl methacrylate.

[0026] (B) As a method for producing the halogenated benzyl acrylate flame retardant, an example of the method for producing the above-mentioned brominated acrylic polymer is a method in which a brominated acrylic monomer is reacted to a predetermined degree of polymerization by solution polymerization or bulk polymerization. In the case of solution polymerization, a solvent is used in which the content of halogenated aromatic compounds is 1000 ppm or less, preferably 500 ppm or less, more preferably 300 ppm or less, and even more preferably 100 ppm or less. It is particularly preferable not to use halogenated aromatic compounds such as halogenated benzene and chlorobenzene as the solvent. In addition, aprotic solvents such as ethylene glycol monomethyl ether, methyl ethyl ketone, ethylene glycol dimethyl ether, and dioxane are preferable as the solvent for solution polymerization.

[0027] The halogenated benzyl acrylate flame retardant (B) such as the brominated acrylic polymer 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. In this specification, "containing alkaline (earth) metal ions" means containing alkaline metal ions and / or alkaline earth metal ions. An aqueous solution containing alkaline (earth) metal ions can be easily obtained by adding an alkaline (earth) metal salt to water, but hydroxides (e.g., calcium hydroxide), which are alkaline (earth) metals that do not contain chloride ions, phosphate ions, etc., are optimal. When calcium hydroxide is used as the alkaline (earth) metal salt, calcium hydroxide is generally soluble in an amount of 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 acrylic polymer in an aqueous solution containing water and / or alkaline (earth) metal ions for an appropriate time may be used. The brominated acrylic polymer that has been subjected to the above-mentioned washing treatment with water and / or an aqueous solution containing an alkaline (earth) metal ion generally has a dry solid content in the hot water extract of 100 ppm or less. When such a brominated acrylic polymer is used, it is almost impossible for foreign matter to be generated on the surface of the molded article.

[0028] The flame-retardant polybutylene terephthalate resin composition of the present invention has a content of halogenated aromatic compounds other than the flame retardant, which is the above-mentioned impurity, of less than 0.5 ppm, preferably 0.3 ppm or less, more preferably 0.1 ppm or less. By the content of halogenated aromatic compounds other than the flame retardant in the flame-retardant polybutylene terephthalate resin composition being within the above range, corrosion of metal terminals can be suppressed in insert moldings using the polybutylene terephthalate resin composition, and the deterioration of physical properties due to hydrolysis of the polybutylene terephthalate resin composition can be suppressed without impairing the effect of adding the hydrolysis resistance improver (C) described later. The content of such halogenated aromatic compounds other than the flame retardant can be determined, for example, from the amount of gas generated by measuring the amount of gas generated by halogenated aromatic compounds by gas chromatography when a sample obtained by pulverizing the polybutylene terephthalate resin composition is heat-treated in the headspace.

[0029] In making the resin flame-retardant, it is preferable to use an antimony-based flame retardant assistant in combination. Representative flame retardant assistants include antimony trioxide, antimony tetraoxide, antimony pentoxide, sodium pyroantimonate, etc. Furthermore, it is also preferable to use a drip prevention agent such as polytetrafluoroethylene in combination in order to prevent the spread of fire caused by dripping of the burned resin.

[0030] The range of addition of the (B) halogenated benzyl acrylate flame retardant and antimony flame retardant assistant to the resin is 3 to 50 parts by mass of the polymer, preferably 5 to 40 parts by mass, and more preferably 10 to 35 parts by mass, per 100 parts by mass of polybutylene terephthalate resin. The range of 1 to 40 parts by mass of the antimony flame retardant assistant is preferred. If the amount of the brominated acrylic polymer and the antimony flame retardant assistant added is too small, sufficient flame retardancy cannot be imparted, and if it is too large, the physical properties of the molded product may deteriorate.

[0031] ((C) Hydrolysis resistance improver) The hydrolysis resistance improver (C) used in the present invention is added in order to improve the hydrolysis resistance, which is required when a molded article made of the flame-retardant polybutylene terephthalate resin composition of the present invention is used in a humid and hot environment.

[0032] (C) Examples of the hydrolysis resistance improver include carbodiimide compounds, epoxy compounds, oxazoline compounds, and oxazine compounds. These can be used alone or in combination of two or more.

[0033] As the carbodiimide compound, a compound having at least one carbodiimide group represented by (-N=C=N-) in the molecule can be used. Such a carbodiimide compound can be produced, for example, by heating an organic isocyanate in the presence of a suitable catalyst and subjecting it to a decarboxylation reaction.

[0034] Examples of the carbodiimide compound include diphenylcarbodiimide, di-cyclohexylcarbodiimide, di-2,6-dimethylphenylcarbodiimide, diisopropylcarbodiimide, dioctyldecylcarbodiimide, di-o-toluylcarbodiimide, di-p-toluylcarbodiimide, di-p-nitrophenylcarbodiimide, di-p-aminophenylcarbodiimide, di-p-hydroxyphenylcarbodiimide, di-p-chlorophenylcarbodiimide, di-o-chlorophenylcarbodiimide, di-3,4-dichlorophenylcarbodiimide, di-2,5-dichlorophenylcarbodiimide, p-phenylene-bis-o-toluylcarbodiimide, p-phenylene-bis- Dicyclohexylcarbodiimide, p-phenylene-bis-di-p-chlorophenylcarbodiimide, 2,6,2',6'-tetraisopropyldiphenylcarbodiimide, hexamethylene-bis-cyclohexylcarbodiimide, ethylene-bis-diphenylcarbodiimide, ethylene-bis-di-cyclohexylcarbodiimide, N,N'-di-o-triylcarbodiimide, N,N'-diphenylcarbodiimide, N,N'-dioctyldecylcarbodiimide, N,N'-di-2,6-dimethylphenylcarbodiimide, N-triyl-N'-cyclohexylcarbodiimide, N,N'-di-2,6-diisopropylphenylcarbodiimide, N,N'-di-2,6-di-tert -butylphenylcarbodiimide, N-toluyl-N'-phenylcarbodiimide, N,N'-di-p-nitrophenylcarbodiimide, N,N'-di-p-aminophenylcarbodiimide, N,N'-di-p-hydroxyphenylcarbodiimide, N,N'-di-cyclohexylcarbodiimide, N,N'-di-p-toluylcarbodiimide, N,N'-benzylcarbodiimide, N-octadecyl-N'-phenylcarbodiimide, N-benzyl-N'-phenylcarbodiimide, N-octadecyl-N'-tolylcarbodiimide, N-cyclohexyl-N'-tolylcarbodiimide, N-phenyl-N'-tolylcarbodiimide, N-benzyl-N'-tolylcarbodiimide, N,N'-di-o-ethylphenylcarbodiimide, N,N'-di-p-ethylphenylcarbodiimide, N,Mono- or dicarbodiimide compounds such as N'-di-o-isopropylphenylcarbodiimide, N,N'-di-p-isopropylphenylcarbodiimide, N,N'-di-o-isobutylphenylcarbodiimide, N,N'-di-p-isobutylphenylcarbodiimide, N,N'-di-2,6-diethylphenylcarbodiimide, N,N'-di-2-ethyl-6-isopropylphenylcarbodiimide, N,N'-di-2-isobutyl-6-isopropylphenylcarbodiimide, N,N'-di-2,4,6-trimethylphenylcarbodiimide, N,N'-di-2,4,6-triisopropylphenylcarbodiimide, and N,N'-di-2,4,6-triisobutylphenylcarbodiimide; poly(1,6-hexamethylene carbodiimide); Examples of polycarbodiimides include poly(4,4'-methylenebiscyclohexylcarbodiimide), poly(1,3-cyclohexylenecarbodiimide), poly(1,4-cyclohexylenecarbodiimide), poly(4,4'-diphenylmethanecarbodiimide), poly(3,3'-dimethyl-4,4'-diphenylmethanecarbodiimide), poly(naphthylenecarbodiimide), poly(p-phenylenecarbodiimide), poly(m-phenylenecarbodiimide), poly(tolylcarbodiimide), poly(diisopropylcarbodiimide), poly(methyl-diisopropylphenylenecarbodiimide), poly(triethylphenylenecarbodiimide), and poly(triisopropylphenylenecarbodiimide). As the polycarbodiimide, a xylylene-based polycarbodiimide synthesized from m-xylylene diisocyanate, p-xylylene diisocyanate, m-tetramethylxylylene diisocyanate, p-tetramethylxylylene diisocyanate, etc. can also be used. Furthermore, a carbodiimide compound obtained by reacting a diisocyanate compound with a diol compound such as polyether polyol, polyester polyol, polycarbonate polyol, silicone diol, polyolefin polyol, polyurethane polyol, alkylene (having 21 or more carbon atoms) diol, etc. can also be used. Among these, from the viewpoint of heat resistance, N,N'-di-2,6-diisopropylphenylcarbodiimide, 2,6,2',Aromatic carbodiimides such as 6'-tetraisopropyldiphenylcarbodiimide are preferred, as are polycarbodiimides.

[0035] The epoxy compound may be any compound containing an epoxy group in its molecular structure, and preferably used are glycidyl ether compounds, glycidyl ester compounds, glycidyl amine compounds, glycidyl imide compounds, and alicyclic epoxy compounds.

[0036] Examples of the glycidyl ether compound include butyl glycidyl ether, stearyl glycidyl ether, allyl glycidyl ether, phenyl glycidyl ether, o-phenylphenyl glycidyl ether, ethylene oxide lauric alcohol glycidyl ether, ethylene oxide phenol glycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, Examples of the epoxy resin include bisphenol A diglycidyl ether type epoxy resin, bisphenol F diglycidyl ether type epoxy resin, and bisphenol S diglycidyl ether type epoxy resin obtained by condensation reaction of bisphenols such as cyclohexane dimethanol diglycidyl ether, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol polyglycidyl ether, 2,2-bis-(4-hydroxyphenyl)propane, 2,2-bis-(4-hydroxyphenyl)methane, and bis(4-hydroxyphenyl)sulfone with epichlorohydrin. Among them, bisphenol A diglycidyl ether type epoxy resin is preferable.

[0037] Examples of the glycidyl ester compound include benzoic acid glycidyl ester, p-toluic acid glycidyl ester, cyclohexane carboxylic acid glycidyl ester, stearic acid glycidyl ester, lauric acid glycidyl ester, palmitic acid glycidyl ester, versatic acid glycidyl ester, oleic acid glycidyl ester, linoleic acid glycidyl ester, linolenic acid glycidyl ester, terephthalic acid diglycidyl ester, isophthalic acid diglycidyl ester, phthalic acid diglycidyl ester, naphthalenedicarboxylic acid diglycidyl ester, and the like. diglycidyl ester, diglycidyl bibenzoate, diglycidyl methyl terephthalate, diglycidyl hexahydrophthalate, diglycidyl tetrahydrophthalate, diglycidyl cyclohexanedicarboxylate, diglycidyl adipic acid, diglycidyl succinate, diglycidyl sebacate, diglycidyl dodecanedicarboxylate, diglycidyl octadecanedicarboxylate, triglycidyl trimellitate, tetraglycidyl pyromellitate, etc. Among these, glycidyl benzoate and glycidyl versatic acid are preferred.

[0038] Examples of the glycidyl amine compound include tetraglycidyl aminodiphenylmethane, triglycidyl-p-aminophenol, triglycidyl-m-aminophenol, diglycidyl aniline, diglycidyl toluidine, tetraglycidyl metaxylenediamine, diglycidyl tribromoaniline, tetraglycidyl bisaminomethylcyclohexane, triglycidyl cyanurate, and triglycidyl isocyanurate.

[0039] Examples of the glycidyl imide compound include N-glycidyl phthalimide, N-glycidyl-4-methylphthalimide, N-glycidyl-4,5-dimethylphthalimide, N-glycidyl-3-methylphthalimide, N-glycidyl-3,6-dimethylphthalimide, N-glycidyl-4-ethoxyphthalimide, N-glycidyl-4-chlorophthalimide, N-glycidyl-4,5-dichlorophthalimide, N-glycidyl-3,4,5,6-tetrabromophthalimide, and N-glycidyl-4-n-butyl-5- Examples of such phthalimide include bromophthalimide, N-glycidyl succinimide, N-glycidyl hexahydrophthalimide, N-glycidyl-1,2,3,6-tetrahydrophthalimide, N-glycidyl maleimide, N-glycidyl-α,β-dimethylsuccinimide, N-glycidyl-α-ethylsuccinimide, N-glycidyl-α-propylsuccinimide, N-glycidyl benzamide, N-glycidyl-p-methylbenzamide, N-glycidyl naphthamide, and N-glycidyl steramide. Of these, N-glycidyl phthalimide is preferred.

[0040] Examples of the alicyclic epoxy compound include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate, bis(3,4-epoxycyclohexylmethyl)adipate, vinylcyclohexene diepoxide, N-methyl-4,5-epoxycyclohexane-1,2-dicarboxylic acid imide, N-ethyl-4,5-epoxycyclohexane-1,2-dicarboxylic acid imide, N-phenyl-4,5-epoxycyclohexane-1,2-dicarboxylic acid imide, N-naphthyl-4,5-epoxycyclohexane-1,2-dicarboxylic acid imide, and N-tolyl-3-methyl-4,5-epoxycyclohexane-1,2-dicarboxylic acid imide.

[0041] Other epoxy compounds that can be used include epoxy-modified fatty acid glycerides such as epoxidized soybean oil, epoxidized linseed oil, and epoxidized whale oil, phenol novolac type epoxy resins, and cresol nosolac type epoxy resins.

[0042] Furthermore, as the epoxy compound, an epoxy-modified resin or an epoxy-modified elastomer obtained by copolymerizing an epoxy compound such as a glycidyl ester of an α,β-unsaturated acid, for example, an acrylic acid glycidyl ester, a methacrylic acid glycidyl ester, or an ethacrylic acid glycidyl ester with another monomer by random, block, or graft copolymerization, specifically, a glycidyl group-containing copolymer consisting of an α-olefin and a glycidyl ester of an α,β-unsaturated acid, a polyorganosiloxane / polyalkyl(meth)acrylate composite rubber graft copolymer obtained by graft polymerization of an epoxy group-containing vinyl monomer, or a styrene / butadiene copolymer elastomer having an epoxy group in the main chain, or a brominated epoxy compound (without blocked epoxy groups) generally used as a flame retardant can also be used.

[0043] Examples of the oxazoline compound include 2-methoxy-2-oxazoline, 2-ethoxy-2-oxazoline, 2-propoxy-2-oxazoline, 2-butoxy-2-oxazoline, 2-pentyloxy-2-oxazoline, 2-hexyloxy-2-oxazoline, 2-heptyloxy-2-oxazoline, 2-octyloxy-2-oxazoline, 2-nonyloxy-2-oxazoline, 2-decyloxy-2-oxazoline, 2-cyclopentyloxy-2-oxazoline, 2-cyclohexyloxy-2-oxazoline, 2-allyloxy-2-oxazoline, and the like. xazoline, 2-methallyloxy-2-oxazoline, 2-crotyloxy-2-oxazoline, 2-phenoxy-2-oxazoline, 2-cresyl-2-oxazoline, 2-o-ethylphenoxy-2-oxazoline, 2-o-propylphenoxy-2-oxazoline, 2-o-phenylphenoxy-2-oxazoline, 2-m-ethylphenoxy-2-oxazoline, 2-m-propylphenoxy-2-oxazoline, 2-p-phenylphenoxy-2-oxazoline, 2-methyl-2-oxazoline, 2-ethyl-2-oxazoline, 2-propyl -2-oxazoline, 2-butyl-2-oxazoline, 2-pentyl-2-oxazoline, 2-hexyl-2-oxazoline, 2-heptyl-2-oxazoline, 2-octyl-2-oxazoline, 2-nonyl-2-oxazoline, 2-decyl-2-oxazoline, 2-cyclopentyl-2-oxazoline, 2-cyclohexyl-2-oxazoline, 2-allyl-2-oxazoline, 2-methallyl-2-oxazoline, 2-crotyl-2-oxazoline, 2-phenyl-2-oxazoline, 2-o-ethylphenyl-2-oxazoline, 2-o-propyl Phenyl-2-oxazoline, 2-o-phenylphenyl-2-oxazoline, 2-m-ethylphenyl-2-oxazoline, 2-m-propylphenyl-2-oxazoline, 2-p-phenylphenyl-2-oxazoline, 2,2′-bis(2-oxazoline), 2,2′-bis(4-methyl-2-oxazoline), 2,2′-bis(4,4′-dimethyl-2-oxazoline), 2,2′-bis(4-ethyl-2-oxazoline), 2,2′-bis(4,4′-diethyl-2-oxazoline), 2,2′-bis(4-propyl-2-oxazoline), 2,2'-bis(4-butyl-2-oxazoline), 2,2'-bis(4-hexyl-2-oxazoline), 2,2'-bis(4-phenyl-2-oxazoline), 2,2'-bis(4-cyclohexyl-2-oxazoline), 2,2'-bis(4-benzyl-2-oxazoline), 2,2'-p-phenylenebis(2-oxazoline), 2,2'-m-phenylenebis(2-oxazoline), 2,2'-o-phenylenebis(2-oxazoline), 2,2'-p-phenylenebis(4-methyl-2-oxazoline), 2,2'-p-phenylenebis(4,4'-dimethyl-2-oxazoline), 2,2'-m-phenylenebis(4-methyl-2-oxazoline), 2,2'-m -phenylenebis(4,4'-dimethyl-2-oxazoline), 2,2'-ethylenebis(2-oxazoline), 2,2'-tetramethylenebis(2-oxazoline), 2,2'-hexamethylenebis(2-oxazoline), 2,2'-octamethylenebis(2-oxazoline), 2,2'-decamethylenebis(2-oxazoline), 2,2'-ethylenebis(4-methyl-2-oxazoline), 2,2'-tetramethylenebis(4,4'-dimethyl-2-oxazoline), 2,2'-9,9'-diphenoxyethanebis(2-oxazoline), 2,2'-cyclohexylenebis(2-oxazoline), 2,2'-diphenylenebis(2-oxazoline), etc. may also be mentioned. Furthermore, polyoxazoline compounds containing the above-mentioned compounds as monomer units may also be mentioned.

[0044] Examples of oxazine compounds include 2-methoxy-5,6-dihydro-4H-1,3-oxazine, 2-ethoxy-5,6-dihydro-4H-1,3-oxazine, 2-propoxy-5,6-dihydro-4H-1,3-oxazine, 2-butoxy-5,6-dihydro-4H-1,3-oxazine, 2-pentyloxy-5,6-dihydro-4H-1,3-oxazine, 2-hexyloxy-5,6-dihydro-4H-1,3-oxazine, and 2-heptyloxy-5,6-dihydro-4H- 1,3-oxazine, 2-octyloxy-5,6-dihydro-4H-1,3-oxazine, 2-nonyloxy-5,6-dihydro-4H-1,3-oxazine, 2-decyloxy-5,6-dihydro-4H-1,3-oxazine, 2-cyclopentyloxy-5,6-dihydro-4H-1,3-oxazine, 2-cyclohexyloxy-5,6-dihydro-4H-1,3-oxazine, 2-allyloxy-5,6-dihydro-4H-1,3-oxazine, 2-methallyloxy-5, 6-dihydro-4H-1,3-oxazine, 2-crotyloxy-5,6-dihydro-4H-1,3-oxazine, etc., further include 2,2'-bis(5,6-dihydro-4H-1,3-oxazine), 2,2'-methylenebis(5,6-dihydro-4H-1,3-oxazine), 2,2'-ethylenebis(5,6-dihydro-4H-1,3-oxazine), 2,2'-propylenebis(5,6-dihydro-4H-1,3-oxazine), 2,2'-butylenebis(5,6-di Hydro-4H-1,3-oxazine), 2,2'-hexamethylenebis(5,6-dihydro-4H-1,3-oxazine), 2,2'-p-phenylenebis(5,6-dihydro-4H-1,3-oxazine), 2,2'-m-phenylenebis(5,6-dihydro-4H-1,3-oxazine), 2,2'-naphthylenebis(5,6-dihydro-4H-1,3-oxazine), 2,2'-P,P'-diphenylenebis(5,6-dihydro-4H-1,3-oxazine), etc. Furthermore, polyoxazine compounds containing the above-mentioned compounds as monomer units, etc. can be mentioned.

[0045] Among the above oxazoline compounds and oxazine compounds, 2,2'-m-phenylenebis(2-oxazoline) and 2,2'-p-phenylenebis(2-oxazoline) are preferred.

[0046] The amount of the (C) hydrolysis resistance improver added is 0.1 to 10 parts by mass, preferably 0.2 to 8 parts by mass, and more preferably 0.3 to 5 parts by mass, per 100 parts by mass of the polybutylene terephthalate resin.

[0047] The amount of the hydrolysis resistance improver (C) added may be set so that the total functional group content of carbodiimide groups, epoxy groups, oxazoline groups, and oxazine rings is 0.3 to 5 equivalents, assuming the amount of terminal carboxyl groups in the polybutylene terephthalate resin composition to be 1. The total functional group content is preferably 0.5 to 3 equivalents, more preferably 0.8 to 2 equivalents.

[0048] (Additives) If necessary, known substances generally added to thermoplastic resins can be added to the composition of the present invention in order to impart desired properties other than flame retardancy and hydrolysis resistance. For example, any of the following can be blended: antioxidants, ultraviolet absorbers, stabilizers such as light stabilizers, antistatic agents, lubricants, release agents, colorants such as dyes and pigments, plasticizers, flow improvers, toughness improvers, impact resistance improvers, and resins other than those corresponding to hydrolysis resistance improvers, fillers, etc. In particular, fillers are effective for the purpose of imparting rigidity and low warpage, and fibrous, granular, or plate-like fillers are used depending on the purpose.

[0049] Examples of fibrous fillers include circular cross-section glass fibers, asbestos fibers, carbon fibers, silica fibers, silica-alumina fibers, zirconia fibers, potassium titanate fibers, and metal fibers such as stainless steel, aluminum, titanium, copper, brass, etc. Organic fibrous materials with high melting points such as fluororesins and acrylic resins can also be used.

[0050] Examples of powdered and granular fillers include glass beads, glass powder, quartz powder, kaolin, clay, diatomaceous earth, wollastonite, iron oxide, titanium oxide, alumina, calcium carbonate, magnesium carbonate, calcium sulfate, barium sulfate, as well as silicon carbide, silicon nitride, and various metal powders.

[0051] Examples of the plate-like inorganic filler include mica, glass flakes, and various metal foils.

[0052] The type of filler is not particularly limited, and one or more types of fillers can be added. In particular, it is preferable to use circular cross-section glass fiber, potassium titanate fiber, mica, and wollastonite.

[0053] The amount of the filler to be added is not particularly limited, but is preferably 200 parts by mass or less per 100 parts by mass of the polybutylene terephthalate resin. When an excessive amount of filler is added, the moldability is poor and a decrease in toughness is observed.

[0054] [Method for producing flame-retardant polybutylene terephthalate resin composition] The form of the flame-retardant polybutylene terephthalate resin composition of the present invention may be a powder mixture or a molten mixture (melt kneaded product) such as pellets. The method for producing a polybutylene terephthalate resin composition according to one embodiment of the present invention includes a process for producing a halogenated benzyl acrylate-based flame retardant (B). This process is as described above, so a description thereof will be omitted here. The method for producing the polybutylene terephthalate resin composition is not particularly limited, and the composition can be produced using equipment and methods known in the art. For example, the necessary components can be mixed and kneaded using a single-screw or twin-screw extruder or other melt kneading device to prepare pellets for molding. A plurality of extruders or other melt kneading devices may be used. All components may be simultaneously fed from a hopper, or some components may be fed from a side feed port.

[0055] The flame-retardant polybutylene terephthalate resin composition of the present invention can be vacuum-dried (vacuum drying step) to remove moisture at the stage of each component (raw material) supplied to the above-mentioned melt kneading and / or at the stage of pellets when used in combination with a metal to form a molded article, thereby making it possible to suppress hydrolysis during processing. EXAMPLES

[0056] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples as long as it does not depart from the gist of the invention. The characteristics were evaluated by the following methods.

[0057] (1) Halogenated aromatic compounds content The materials dry-blended with the components and composition (parts by mass) shown in Table 1 were fed to a twin-screw extruder (manufactured by Japan Steel Works, Ltd.) with a 30 mmφ screw and melt-kneaded at 260°C, and the pellets of the resulting polybutylene terephthalate resin composition were crushed and used as a sample. 5 g of the sample was taken and left in a 20 ml headspace at 150°C for 1 hour, and then the sample was heated at 5°C / min using a Yokogawa Hewlett-Packard HP5890A apparatus and a HR-1701 (0.32 mm diameter x 30 m) column after holding at 50°C for 1 minute. The amount of gas generated from halogenated aromatic compounds was measured by gas chromatography, and the content of halogenated aromatic compounds was expressed in ppm. The results are shown in Table 1.

[0058] (2) Metal corrosiveness Materials dry-blended with the components and compositions (parts by mass) shown in Table 1 were fed to a twin-screw extruder (manufactured by Japan Steel Works, Ltd.) with a 30 mmφ screw and melt-kneaded at 260°C, and 50 g of the resulting polybutylene terephthalate resin composition pellets were placed in a 300 ml glass stoppered bottle together with a 1 cm x 1 cm silver plate, the bottle was plugged, and the bottle was left to stand in a Geer oven at 150°C for 500 hours, after which the surface of the silver plate was visually inspected and evaluated as ◯ if no corrosion had occurred and × if corrosion had occurred. The results are shown in Table 1.

[0059] (3) Flame retardancy The materials dry-blended with the components and compositions (parts by mass) shown in Table 1 were fed to a twin-screw extruder (manufactured by The Japan Steel Works, Ltd.) having a screw of 30 mmφ and melt-kneaded at 260°C, and the resulting pellets of polybutylene terephthalate resin composition were dried at 140°C for 3 hours and then injection-molded at a cylinder temperature of 250°C and a mold temperature of 70°C to prepare test pieces having a thickness of 1 / 32 inch in accordance with UL94, and their flammability was evaluated. The results are shown in Table 1.

[0060] (4) Hydrolysis resistance The material dry-blended with the components and composition (parts by mass) shown in Table 1 was fed to a twin-screw extruder (manufactured by The Japan Steel Works, Ltd.) having a screw of 30 mmφ and melt-kneaded at 260°C. The resulting pellets of polybutylene terephthalate resin composition were dried at 140°C for 3 hours and then injection-molded under conditions of a cylinder temperature of 260°C and a mold temperature of 80°C to prepare tensile test pieces according to ISO3167 Type1A, and the tensile breaking strain was measured in accordance with ISO527-1,2. The same tensile test piece was subjected to high temperature and humidity treatment at 121°C and 100% RH for 60 hours using a pressure cooker test (PCT) device, and the tensile breaking strain was measured in the same manner as described above to determine the retention rate relative to before treatment (tensile breaking strain after treatment ÷ tensile breaking strain before treatment × 100 (%)). The hydrolysis resistance was evaluated by assigning a ◎ to a retention rate of 90% or more after 60 hours of treatment, a ○ to a retention rate of 80% or more, a △ to a retention rate of 50% or more, and an × to a retention rate of less than 50%. The results are shown in Table 1.

[0061] [Table 1] ND in the table indicates that the value is below the detection limit (0.1 ppm). The unit of content is parts by mass.

[0062] Details of each component listed in Table 1 are as follows. (A) PBT resin: polybutylene terephthalate resin manufactured by WinTech Polymer Co., Ltd., with a terminal carboxyl group concentration of 20 meq / kg and an intrinsic viscosity of 0.7 dL / g (B-1) PBBPA1: Polypentabromobenzyl acrylate polymerized using ethylene glycol monomethyl ether as a solvent (content of halogenated aromatic compounds other than flame retardants: 8 ppm) (B-2) PBBPA2: Polypentabromobenzyl acrylate polymerized using chlorobenzene as a solvent (content of halogenated aromatic compounds other than flame retardants: 150 ppm) (C) Hydrolysis resistance improver: aromatic carbodiimide (STABAXOL P, manufactured by Rhein Chemie Japan) Glass fiber: Nippon Electric Glass Co., Ltd., ECS03T-127 (average fiber diameter 13 μm, average fiber length 3 mm) Antimony trioxide: PATOX-M, manufactured by Nihon Seiko Co., Ltd. Anti-drip agent: Polytetrafluoroethylene resin

Claims

1. (A) 100 parts by mass of polybutylene terephthalate resin; (B) 3 to 50 parts by mass of a halogenated benzyl acrylate flame retardant; (C) 0.3 to 5 parts by mass of a hydrolysis resistance improver; a flame-retardant polybutylene terephthalate resin composition having a content of halogenated aromatic compounds other than the flame retardant of less than 0.1 ppm as measured by headspace gas chromatography (heated at 150° C. for 1 hour); The hydrolysis resistance improver contains a carbodiimide compound, the tensile breaking strain of the molded article measured in accordance with ISO 527-1, 2 after treatment at 121°C and 100% RH for 60 hours is 80% or more of the tensile breaking strain before the treatment; A flame-retardant polybutylene terephthalate resin composition in which 50 g of the composition is placed in a 300 mL glass stoppered bottle together with a 1 cm x 1 cm silver plate, the bottle is stopped up, and the bottle is left at 150°C for 500 hours. After this, no corrosion occurs on the surface of the silver plate.

2. 2. The flame-retardant polybutylene terephthalate resin composition according to claim 1, wherein the halogenated benzyl acrylate flame retardant (B) contains a brominated acrylic polymer represented by general formula (I): 【Chemistry 1】 (In the formula, X is a hydrogen atom or a bromine atom, at least one X is a bromine atom, and m is a number from 10 to 2000.)

3. 3. The flame-retardant polybutylene terephthalate resin composition according to claim 1 or 2, wherein the halogenated benzyl acrylate flame retardant (B) contains polypentabromobenzyl acrylate.

4. The flame-retardant polybutylene terephthalate resin composition according to claim 1 , wherein the halogenated aromatic compound other than the flame retardant contains a halogenated benzene.

5. The flame-retardant polybutylene terephthalate resin composition according to claim 1 , wherein the halogenated aromatic compound other than the flame retardant contains chlorobenzene.

6. The flame-retardant polybutylene terephthalate resin composition according to claim 2, wherein the halogenated benzyl acrylate flame retardant (B) has a content of halogenated aromatic compounds other than the brominated acrylic polymer represented by the general formula (I) of 100 ppm or less.

7. A method for producing the flame-retardant polybutylene terephthalate resin composition according to any one of claims 1 to 6, comprising the steps of: (B) A production method comprising a step of producing a halogenated benzyl acrylate-based flame retardant, the step being characterized in that a solvent having a content of halogenated aromatic compounds of 1000 ppm or less is used.

8. The method according to claim 7, wherein in the production process of the halogenated benzyl acrylate-based flame retardant (B), no halogenated aromatic compound is used as a solvent.

9. The method according to claim 7 or 8, wherein in the production process of the halogenated benzyl acrylate flame retardant (B), one or more solvents selected from the group consisting of ethylene glycol monomethyl ether, methyl ethyl ketone, ethylene glycol dimethyl ether and dioxane are used as a solvent.

10. The method according to claim 7 , further comprising a vacuum drying step.

11. The method according to any one of claims 7 to 10, wherein in the production process of the halogenated benzyl acrylate flame retardant (B), a solvent selected from the group consisting of ethylene glycol monomethyl ether, methyl ethyl ketone, ethylene glycol dimethyl ether and dioxane is used as a solvent.

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