Thermoplastic polyester resin composition and molded article

Abstract

The purpose of the present invention is to obtain a molded article that has excellent fire-resistance and tracking resistance, that has excellent mechanical properties and hydrolysis resistance, and that is unlikely to cause bleed out even in a high temperature and high humidity environment. The thermoplastic polyester resin composition according to the present invention is obtained by blending, with respect to (A) 100 parts by weight of a thermoplastic polyester resin, (B) 0.1-50 parts by weight of at least one phosphinate selected from phosphinates and diphosphinates, (C) 0.1-10 parts by weight of a phosphazene compound, (D) 0.1-50 parts by weight of a nitrogen-based flame retardant, (E) 0.1-10 parts by weight of a polyfunctional epoxy compound, and (F) 0.1-20 parts by weight of an olefin resin. The ratio of the parts by weight of component (B) and the parts by weight of component (C) is 2.0-8.0.

Description

[Technical Field]

[0001] The present invention relates to a thermoplastic polyester resin composition and a molded article obtained by molding the same. [Background technology]

[0002] Thermoplastic polyester resins, thanks to their excellent injection moldability and mechanical properties, are used in a wide range of applications, including mechanical components, electrical and electronic components, and automotive parts. Furthermore, because polyester resins are crystalline plastics with high melting points, high processing temperatures are required for melt-blending extruders and injection molding machines. However, because thermoplastic polyester resins are inherently flammable, their use in industrial applications, such as mechanical components, electrical and electronic components, and automotive parts, requires a balance of general chemical and physical properties as well as flame safety, i.e., flame retardancy. High flame retardancy, often meeting the UL-94 standard of V-0, is required. Furthermore, because thermoplastic polyester resins are susceptible to degradation by hydrolysis, their use in industrial applications, such as mechanical components, electrical and electronic components, and automotive parts, requires long-term hydrolysis resistance in addition to a balance of general chemical and physical properties. In recent years, there has been an increasing demand for thinner and lighter molded products as well as smaller sizes. Particularly in applications for thin-walled molded products such as connectors, if viscosity changes significantly during molten retention, molding defects such as flash and short shots occur during molding. Therefore, there is a demand for materials with excellent retention stability that exhibit minimal viscosity changes during molten retention.

[0003] The most common method of imparting flame retardancy to polyester resin is to compound a halogenated organic compound as a flame retardant and an antimony compound as a flame retardant aid to the resin, but with growing environmental awareness, there is a movement to worry about the environmental impact of halogenated organic compounds. Furthermore, when used in an electrically conducting environment, safety against tracking breakdown, which occurs when the resin decomposes or carbonizes due to discharge and ignites, is required, i.e., tracking resistance, and in many cases a high level of tracking resistance is required, indicating CTI rank 0 according to the IEC 60112 standard.

[0004] In particular, electric vehicles have been attracting attention in recent years due to growing environmental awareness, and even higher levels of tracking resistance are required, but there has been a problem in that when the above-mentioned halogen-based organic compounds and antimony compounds are compounded with polyester resins, tracking resistance is significantly reduced. Therefore, in recent years, there has been a strong desire to use non-halogen flame retardants that do not contain these halogens at all, and it has been proposed to blend, for example, phosphorus-based flame retardants such as phosphinates and phosphazene compounds, and nitrogen-based flame retardants such as melamine cyanurate as flame retardants.

[0005] Examples of flame-retardant resin compositions using non-halogen flame retardants include thermoplastic polyester resins, moist heat-resistant phosphorus-based flame retardants such as diamine phosphates, phosphorus-based flame retardants, nitrogen-containing flame retardants, and anti-drip agents (Patent Document 1); resin compositions containing a thermoplastic resin, phosphinates, and anti-metal corrosion agents having a specific structure (Patent Document 2); resin compositions containing a thermoplastic polyester resin, methacrylic resins, condensed phosphate esters, phosphazene compounds, and organic metal phosphinates, and nitrogen-based flame retardants (Patent Document 3); resin compositions containing a thermoplastic polyester resin, phosphinates, nitrogen compounds, and one or more phosphorus-based compounds selected from phosphate ester compounds, phosphazene compounds, and phosphaphenanthrene compounds (Patent Document 4); Patent Document 5 discloses a resin composition containing phosphates, a phosphazene compound, a nitrogen-containing flame retardant, an enhancer, and other additives; Patent Document 6 discloses a flame-retardant formulation for thermoplastic polymers containing phosphinates, a phosphazene compound, an inorganic zinc compound, and a nitrogen-containing flame retardant; Patent Document 7 discloses a resin composition containing polybutylene terephthalate resin, a thermoplastic polyester elastomer, a phosphazene compound, an epoxy compound, and a polyorganosiloxane; Patent Document 8 discloses a resin composition containing polybutylene terephthalate resin, a phosphinate, a phosphazene compound, and a nitrogen-containing cyclic compound; and Patent Document 9 discloses a resin composition containing polyalkylene terephthalate resin, a polystyrene resin, a compatibilizer, a phosphorus-based flame retardant selected from phosphazenes and phosphinates, and a nitrogen-based flame retardant.

[0006] Furthermore, as a technique for improving the hydrolysis resistance of a thermoplastic polyester resin, for example, Patent Document 10 discloses a resin composition obtained by blending a biphenylaralkyl-type epoxy resin or a dicyclopentadiene-type epoxy resin with a thermoplastic polyester resin. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2019-44037 [Patent Document 2] International Publication No. 2011 / 007687 [Patent Document 3] International Publication No. 2014 / 021101 [Patent Document 4] Japanese Patent Application Laid-Open No. 2010-202748 [Patent Document 5] Special Publication No. 2013-544921 [Patent Document 6] Special Publication No. 2018-525449 [Patent Document 7] Japanese Patent Application Laid-Open No. 2006-152122 [Patent Document 8] International Publication No. 2014 / 084157 [Patent Document 9] Japanese Patent Application Laid-Open No. 2009-292897 [Patent Document 10] International Publication No. 2015 / 072216 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the phosphorus-based flame retardants such as phosphinates and condensed phosphate esters disclosed in Patent Documents 1 to 9 are acidic compounds, and therefore when they are blended with a thermoplastic polyester resin, the acid acts as a catalyst that cleaves the ester groups of the thermoplastic polyester resin, which tends to reduce the mechanical properties and also significantly reduces hydrolysis resistance.

[0009] In response to this, Patent Document 10 discloses a technique for improving the hydrolysis resistance of a thermoplastic polyester resin by blending a biphenylaralkyl epoxy resin or a dicyclopentadiene epoxy resin with the thermoplastic polyester resin. However, since the epoxy groups of the epoxy resin are also ring-opened by the acid of the phosphorus-based flame retardant, simply using the epoxy resin disclosed in Patent Document 10 in combination with the phosphorus-based flame retardants disclosed in Patent Documents 1 to 9 results in problems such as insufficient mechanical properties and hydrolysis resistance and deterioration of retention stability.

[0010] In addition, there is a problem that corrosive gases generated from phosphorus-based flame retardants such as phosphinates and condensed phosphate esters disclosed in Patent Documents 1 to 9 corrode the screws of the kneading machine or the molds of the injection molding machine. Furthermore, metals such as terminals that come into contact with the obtained thermoplastic resin molded product may corrode, potentially causing contact contamination. Patent Documents 2 and 7 disclose technologies to inhibit metal corrosion, but it has been difficult to achieve both metal corrosion resistance and a high level of hydrolysis resistance.

[0011] Furthermore, the phosphazene compounds mentioned in Patent Documents 1 to 9 have a problem of low flame retardancy, and therefore need to be used in combination with a phosphorus-based flame retardant such as a phosphinate or condensed phosphate ester, which has high flame retardancy, resulting in a problem of reduced mechanical properties and hydrolysis resistance.

[0012] For the reasons described above, it is difficult for the techniques disclosed in Patent Documents 1 to 10 to obtain a material that satisfies all of the requirements for flame retardancy and tracking resistance, mechanical properties and hydrolysis resistance that are reduced by the incorporation of a phosphorus-based flame retardant, and metal corrosion resistance and retention stability.

[0013] An object of the present invention is to provide a thermoplastic polyester resin composition from which molded articles having excellent flame retardancy, tracking resistance, mechanical properties, hydrolysis resistance, and metal corrosion resistance can be obtained, despite the inclusion of a phosphorus-based flame retardant, and a molded article thereof. [Means for solving the problem]

[0014] The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result have discovered that the above-mentioned problems can be solved by blending 100 parts by weight of (A) a thermoplastic polyester resin with 0.1 to 50 parts by weight of (B) at least one phosphinate selected from phosphinates and diphosphinates, 0.1 to 10 parts by weight of (C) a phosphazene compound, 0.1 to 50 parts by weight of (D) a nitrogen-based flame retardant, 0.1 to 10 parts by weight of (E) a multifunctional epoxy compound, and 0.1 to 20 parts by weight of (F) an olefin resin, and by setting the ratio of the parts by weight of component (B) to the parts by weight of component (C) to a specific value, thereby arriving at the present invention. That is, the present invention has the following configuration. [1] A thermoplastic polyester resin composition comprising (A) 100 parts by weight of a thermoplastic polyester resin, (B) 0.1 to 50 parts by weight of at least one phosphinate selected from phosphinates and diphosphinates, (C) 0.1 to 10 parts by weight of a phosphazene compound, (D) 0.1 to 50 parts by weight of a nitrogen-based flame retardant, (E) 0.1 to 10 parts by weight of a polyfunctional epoxy compound, and (F) 0.1 to 20 parts by weight of an olefin resin, and satisfying the following requirement (i): (i) The ratio of the parts by weight of the at least one phosphinate salt selected from the (B) phosphinate salt and the diphosphinate salt to the parts by weight of the (C) phosphazene compound (parts by weight of the (B) component per 100 parts by weight of the (A) component / parts by weight of the (C) component per 100 parts by weight of the (A) component) is 2.0 to 8.0. [2] The thermoplastic polyester resin composition according to [1], wherein the content of the phosphazene compound (C) is 1% by mass or more and less than 5% by mass based on 100% by mass of the thermoplastic polyester resin composition. [3] The thermoplastic polyester resin composition according to [1] or [2], characterized in that, when the total amount of the (B) at least one phosphinate selected from phosphinates and diphosphinates, the (C) phosphazene compound, and the (D) nitrogen-based flame retardant is taken as 100% by mass, the (B) at least one phosphinate selected from phosphinates and diphosphinates accounts for 30 to 65% by mass, the (C) phosphazene compound accounts for 5 to 40% by mass, and the (D) nitrogen-based flame retardant accounts for 30 to 65% by mass. [4] The thermoplastic polyester resin composition according to any one of [1] to [3], wherein the (E) polyfunctional epoxy compound contains at least a novolac epoxy. [5] The thermoplastic polyester resin composition according to any one of [1] to [4], wherein the (F) olefin resin contains at least an olefin resin modified with an acid. [6] The thermoplastic polyester resin composition according to any one of [1] to [5], further comprising 0.001 to 0.5 parts by weight of (G) a metal corrosion resistant agent, based on 100 parts by weight of (A) the thermoplastic polyester resin. [7] The thermoplastic polyester resin composition according to any one of [1] to [6], further comprising 0.001 to 0.5 parts by weight of (H) a residence stability improver, based on 100 parts by weight of (A) the thermoplastic polyester resin. [8] The thermoplastic polyester resin composition according to any one of [1] to [7], further comprising 1 to 100 parts by weight of (I) a fibrous reinforcing material, based on 100 parts by weight of (A) the thermoplastic polyester resin. [9] The thermoplastic polyester resin composition according to any one of [1] to [8], further comprising 0.01 to 1 part by weight of an anti-drip agent (J) based on 100 parts by weight of the thermoplastic polyester resin (A).

[10] The thermoplastic polyester resin composition according to any one of [1] to [9], wherein the thermoplastic polyester resin (A) is a polybutylene terephthalate resin.

[11] The thermoplastic polyester resin composition according to any one of [1] to

[10] , wherein the ratios of the tensile strength after 50 hours and after 100 hours of exposure in an atmosphere of 100% relative humidity and 121°C temperature to the tensile strength before exposure of an ASTM No. 1 dumbbell (1 / 8 inch thick) test piece for evaluating tensile properties molded in accordance with ASTM D638 (2005) (tensile strength retention (%) = ((tensile strength after exposure / tensile strength before exposure) × 100)) are 60% or more and 40% or more, respectively.

[12] A molded article obtained by melt molding the thermoplastic polyester resin composition according to any one of [1] to

[11] .

[13] The molded article according to

[12] , having a comparative tracking index of 400V or more in accordance with IEC 60112. [Effects of the Invention]

[0015] The thermoplastic polyester resin composition of the present invention does not contain a halogen-based flame retardant such as a bromine-containing resin, and has excellent flame retardancy, tracking resistance, and metal corrosion resistance, as well as excellent mechanical properties and hydrolysis resistance, and can give molded articles that are less likely to bleed out even in high-temperature, high-humidity environments. DETAILED DESCRIPTION OF THE INVENTION

[0016] Next, the thermoplastic polyester resin composition of the present invention will be described in detail.

[0017] The thermoplastic polyester resin composition of the present invention is a thermoplastic polyester resin composition comprising 100 parts by weight of (A) a thermoplastic polyester resin, and blended therein: (B) 0.1 to 50 parts by weight of at least one phosphinate salt selected from phosphinates and diphosphinates; (C) 0.1 to 10 parts by weight of a phosphazene compound; (D) 0.1 to 50 parts by weight of a nitrogen-based flame retardant; (E) 0.1 to 10 parts by weight of a polyfunctional epoxy compound; and (F) 0.1 to 20 parts by weight of an olefin resin, and satisfies the following requirement (i): (i) The ratio of the parts by weight of the at least one phosphinate salt selected from the (B) phosphinate salts and diphosphinate salts to the parts by weight of the (C) phosphazene compound (parts by weight of the (B) component per 100 parts by weight of the (A) component / parts by weight of the (C) component per 100 parts by weight of the (A) component) is 2.0 to 8.0.

[0018] Although (A) thermoplastic polyester resins generally have excellent injection moldability and mechanical properties, their low limiting oxygen index means that they will burn if they are close to a fire source such as an open flame. In the present invention, the flame retardancy of (A) thermoplastic polyester resin is enhanced by blending, with respect to 100 parts by weight of (A) thermoplastic polyester resin, 0.1 to 50 parts by weight of (B) at least one phosphinate selected from phosphinates and diphosphinates (hereinafter sometimes referred to as "(B) phosphinates"), 0.1 to 10 parts by weight of (C) a phosphazene compound, 0.1 to 50 parts by weight of (D) a nitrogen-based flame retardant, 0.1 to 10 parts by weight of (E) a multifunctional epoxy compound, and 0.1 to 20 parts by weight of (F) an olefin resin. Phosphinates (B), commonly used as phosphorus-based flame retardants, improve flame retardancy by promoting the formation of a char layer during combustion of thermoplastic polyester resins (A). However, they also produce acidic components due to the decomposition of the phosphorus-based flame retardant under high-temperature, high-humidity conditions, which has been found to significantly impair the mechanical strength and hydrolysis resistance of thermoplastic polyester resins (A). Therefore, by using a phosphazene compound (C) and a multifunctional epoxy compound (E) in combination with a phosphorus-based flame retardant, the generation of acidic components due to the decomposition of the phosphorus-based flame retardant is suppressed, while the carboxyl terminal groups derived from the thermoplastic polyester resin (A) that are generated by hydrolysis are reactively blocked and repaired, achieving high levels of mechanical strength, hydrolysis resistance, flame retardancy, and tracking resistance.

[0019] The thermoplastic polyester resin composition of the present invention contains reaction products of components (A), (B), (C), (D), (E), and (F) each reacted with the other components, but these reaction products are produced by complex reactions, and there are circumstances in which it is impractical to identify their structures. Therefore, the present invention is defined by the components to be blended.

[0020] The thermoplastic polyester resin (A) used in the present invention is a polymer or copolymer having, as its main structural unit, at least one residue selected from the group consisting of (1) dicarboxylic acid or its ester-forming derivative and diol or its ester-forming derivative, (2) hydroxycarboxylic acid or its ester-forming derivative, and (3) lactone. Here, "having as the main structural unit" refers to having at least one residue selected from the group consisting of (1) to (3) in 50 mol % or more of all structural units, with a preferred embodiment being having at least 80 mol % of these residues. Among these, polymers or copolymers having, as their main structural units, (1) residues of dicarboxylic acid or its ester-forming derivative and diol or its ester-forming derivative are preferred because of their superior mechanical properties and heat resistance.

[0021] Examples of the dicarboxylic acid or its ester-forming derivative include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, bis(p-carboxyphenyl)methane, anthracenedicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 5-tetrabutylphosphoniumisophthalate, and 5-sodiumsulfoisophthalic acid; aliphatic dicarboxylic acids such as oxalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, malonic acid, glutaric acid, and dimer acid; alicyclic dicarboxylic acids such as 1,3-cyclohexanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid; and ester-forming derivatives thereof. Two or more of these may be used.

[0022] Examples of the diol or its ester-forming derivative include aliphatic or alicyclic glycols having 2 to 20 carbon atoms, such as ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, decamethylene glycol, cyclohexanedimethanol, cyclohexanediol, and dimer diol; long-chain glycols having a molecular weight of 200 to 100,000, such as polyethylene glycol, poly-1,3-propylene glycol, and polytetramethylene glycol; aromatic dioxy compounds, such as 4,4'-dihydroxybiphenyl, hydroquinone, t-butylhydroquinone, bisphenol A, bisphenol S, and bisphenol F; and ester-forming derivatives thereof. Two or more of these may be used.

[0023] Examples of polymers or copolymers having a dicarboxylic acid or its ester-forming derivative and a diol or its ester-forming derivative as structural units include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polypropylene isophthalate, polybutylene isophthalate, polybutylene naphthalate, polypropylene isophthalate / terephthalate, polybutylene isophthalate / terephthalate, polypropylene terephthalate / naphthalate, polybutylene terephthalate / naphthalate, polybutylene terephthalate / decanedicarboxylate, polypropylene terephthalate / 5-sodium sulfoisophthalate, polybutylene terephthalate / 5-sodium sulfoisophthalate, polypropylene terephthalate / polyethylene glycol, and polybutylene terephthalate / polyethylene Examples of aromatic polyester resins include polyethylene glycol, polypropylene terephthalate / polytetramethylene glycol, polybutylene terephthalate / polytetramethylene glycol, polypropylene terephthalate / isophthalate / polytetramethylene glycol, polybutylene terephthalate / isophthalate / polytetramethylene glycol, polybutylene terephthalate / succinate, polypropylene terephthalate / adipate, polybutylene terephthalate / adipate, polypropylene terephthalate / sebacate, polybutylene terephthalate / sebacate, polypropylene terephthalate / isophthalate / adipate, polybutylene terephthalate / isophthalate / succinate, polybutylene terephthalate / isophthalate / adipate, and polybutylene terephthalate / isophthalate / sebacate. Here, " / " indicates a copolymer.

[0024] Among these, from the viewpoint of further improving mechanical properties and heat resistance, polymers or copolymers having, as main structural units, a residue of an aromatic dicarboxylic acid or an ester-forming derivative thereof and a residue of an aliphatic diol or an ester-forming derivative thereof are more preferred, and polymers or copolymers having, as main structural units, a residue of terephthalic acid, naphthalenedicarboxylic acid or an ester-forming derivative thereof and a residue of an aliphatic diol selected from propylene glycol and 1,4-butanediol or an ester-forming derivative thereof are even more preferred.

[0025] Among these, aromatic polyester resins such as polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polypropylene naphthalate, polybutylene naphthalate, polypropylene isophthalate / terephthalate, polybutylene isophthalate / terephthalate, polypropylene terephthalate / naphthalate, and polybutylene terephthalate / naphthalate are particularly preferred, with polyethylene terephthalate, polypropylene terephthalate, and polybutylene naphthalate being more preferred, and polybutylene terephthalate resin being even more preferred due to its excellent moldability and crystallinity. Furthermore, two or more of these can be used in any desired content.

[0026] In the present invention, the proportion of terephthalic acid or its ester-forming derivative relative to all dicarboxylic acids constituting the polymer or copolymer having, as main structural units, the above-mentioned residues of dicarboxylic acids or their ester-forming derivatives and residues of diols or their ester-forming derivatives is preferably 30 mol % or more, and more preferably 40 mol % or more.

[0027] In the present invention, the thermoplastic polyester resin (A) may be a liquid crystalline polyester resin that can exhibit anisotropy when melted. Examples of structural units of the liquid crystalline polyester resin include an aromatic oxycarbonyl unit, an aromatic dioxy unit, an aromatic and / or aliphatic dicarbonyl unit, an alkylenedioxy unit, and an aromatic iminoxy unit.

[0028] The carboxyl group amount of the thermoplastic polyester resin (A) used in the present invention is preferably 50 eq / t or less in terms of fluidity, hydrolysis resistance, and heat resistance. If it exceeds 50 eq / t, the carboxyl group may act as an acid catalyst, resulting in a significant decrease in hydrolysis resistance. It is more preferably 40 eq / t or less, and even more preferably 30 eq / t or less. The lower limit of the carboxyl group amount is approximately 0 eq / t. Here, the carboxyl group amount of the thermoplastic polyester resin (A) is the value measured by dissolving the thermoplastic polyester resin (A) in an o-cresol / chloroform solvent and then titrating with ethanolic potassium hydroxide.

[0029] The thermoplastic polyester resin (A) used in the present invention preferably has a weight-average molecular weight (Mw) of 8,000 or more in order to further improve mechanical properties. Furthermore, the upper limit of the weight-average molecular weight (Mw) is preferably 500,000 or less, since this improves fluidity. It is more preferably 300,000 or less, and even more preferably 250,000 or less. In the present invention, the Mw of the thermoplastic polyester resin (A) is a value calculated as polymethyl methacrylate (PMMA) as measured by gel permeation chromatography (GPC) using hexafluoroisopropanol as a solvent.

[0030] The thermoplastic polyester resin (A) used in the present invention can be produced by a known polycondensation method, ring-opening polymerization method, etc. The production method may be either batch polymerization or continuous polymerization, and either transesterification or direct polymerization can be applied, but from the viewpoint of productivity, continuous polymerization is preferred, and direct polymerization is more preferred.

[0031] When the thermoplastic polyester resin (A) used in the present invention is a polymer or copolymer obtained by a condensation reaction of a dicarboxylic acid or its ester-forming derivative and a diol or its ester-forming derivative as the main components, it can be produced by subjecting the dicarboxylic acid or its ester-forming derivative and the diol or its ester-forming derivative to an esterification reaction or an ester exchange reaction, followed by a polycondensation reaction.

[0032] In order to effectively promote the esterification reaction or transesterification reaction and polycondensation reaction, it is preferable to add a polymerization catalyst during these reactions. Specific examples of the polymerization catalyst include organotitanium compounds such as methyl ester, tetra-n-propyl ester, tetra-n-butyl ester, tetraisopropyl ester, tetraisobutyl ester, tetra-tert-butyl ester, cyclohexyl ester, phenyl ester, benzyl ester, tolyl ester, or mixed esters thereof of titanic acid, dibutyltin oxide, methylphenyltin oxide, tetraethyltin, hexaethylditin oxide, cyclohexahexylditin oxide, didodecyltin oxide, and triethyltin hydroxide. Examples of suitable antimony compounds include tin compounds such as tin oxide, triphenyltin hydroxide, triisobutyltin acetate, dibutyltin diacetate, diphenyltin dilaurate, monobutyltin trichloride, dibutyltin dichloride, tributyltin chloride, dibutyltin sulfide, butylhydroxytin oxide, alkylstannoic acids such as methylstannoic acid, ethylstannoic acid, and butylstannoic acid, zirconia compounds such as zirconium tetra-n-butoxide, and antimony compounds such as antimony trioxide and antimony acetate. Two or more of these compounds may be used.

[0033] Among these polymerization catalysts, organic titanium compounds and tin compounds are preferred, and tetra-n-butyl ester of titanic acid is more preferred. The amount of the polymerization catalyst added is preferably in the range of 0.01 to 0.2 parts by weight per 100 parts by weight of the thermoplastic polyester resin.

[0034] The thermoplastic polyester resin composition of the present invention contains (B) at least one phosphinate selected from phosphinates and diphosphinates to improve flame retardancy. The (B) phosphinate promotes the formation of a char layer on the (A) thermoplastic polyester resin during combustion, thereby further improving flame retardancy.

[0035] The phosphinate in the present invention is a compound having a structure represented by the following formula (1).

[0036] [ka]

[0037] (In the formula, R1 and R2 may be the same or different and represent a hydrogen atom, an alkyl group having 1 to 16 carbon atoms, or an aryl group, which may be linear or branched. M represents sodium, magnesium, nickel, manganese, calcium, aluminum, or zinc. n represents an integer of 1 to 4.) The diphosphinate in the present invention is a compound having a structure represented by the following formula (2).

[0038] [ka]

[0039] (In the formula, R1' and R2' may be the same or different and represent a hydrogen atom, an alkyl group or an aryl group having 1 to 16 carbon atoms, which may be linear or branched. R3' represents a linear or branched alkylene group having 1 to 10 carbon atoms, or an arylene group, alkylarylene group or arylalkylene group having 6 to 10 carbon atoms. M' represents sodium, magnesium, nickel, manganese, calcium, aluminum or zinc. n' represents an integer of 1 to 4.) In the present invention, a polymer of a phosphinate or a polymer of a diphosphinate can also be used as the phosphinate (B). Examples of such compounds include those having the structures described in JP-A-2002-540224.

[0040] Aluminum is preferred as the metal component in terms of excellent mechanical properties, corrosion resistance to metals, melt retention stability, fluidity, flame retardancy, etc. Specific examples of (B) phosphinates include aluminum hypophosphite, aluminum ethylmethylphosphinate, and aluminum diethylphosphinate, with aluminum diethylphosphinate being more preferred. Commercially available (B) phosphinates include aluminum hypophosphite "Phoslite" (registered trademark) IP-A manufactured by Italmatch Chemicals, and "Exolit" (registered trademark) OP1230 and OP1240 manufactured by Clariant Japan.

[0041] In the present invention, the blending amount of (B) phosphinate salts is 0.1 to 50 parts by weight per 100 parts by weight of (A) thermoplastic polyester resin from the viewpoint of flame retardancy and hydrolysis resistance. If the blending amount of (B) component is less than 0.1 part by weight, flame retardancy will decrease. It is more preferably 1 part by weight or more, even more preferably 10 parts by weight or more, and most preferably 18 parts by weight or more. On the other hand, if the blending amount of (B) component exceeds 50 parts by weight, mechanical strength and hydrolysis resistance will decrease. It is more preferably 30 parts by weight or less, even more preferably 25 parts by weight or less.

[0042] The thermoplastic polyester resin composition of the present invention contains (C) a phosphazene compound in order to improve flame retardancy, tracking resistance, mechanical properties and hydrolysis resistance.

[0043] The phosphazene compound (C) in the present invention may be any compound having a -P=N- bond in the molecule, and examples thereof include linear or cyclic phosphazene compounds having a structure represented by the following general formula (3):

[0044] [ka]

[0045] (In the above general formula (3), m represents an integer of 1 to 1000. R3 and R4 each independently represent a hydrogen atom, a linear, branched, or cyclic alkyl group having from 1 to 18 carbon atoms, a linear, branched, or cyclic alkoxyl group having from 1 to 30 carbon atoms, an aryl group having from 6 to 30 carbon atoms, or an aryloxy group having from 6 to 30 carbon atoms.) In the above general formula (3), examples of the alkyl group include a methyl group and an ethyl group. Examples of the alkoxyl group include a methoxy group and an ethoxy group. Examples of the aryl group include a phenyl group. Examples of the aryloxy group include a phenyloxy group. m is preferably 3 to 30, and the compound preferably contains at least a cyclic phosphazene compound in which the structure represented by the above general formula (3) is cyclically bonded.

[0046] The phosphazene compound (C) may be a crosslinked phosphazene compound. Such a crosslinked phosphazene compound can be obtained, for example, by crosslinking a linear or cyclic phosphazene compound represented by the above general formula (3) via a divalent crosslinking group, and examples of such a crosslinked phosphazene compound include phosphazene compounds having a structure represented by the following general formula (4):

[0047] [ka]

[0048] (In the above general formula (4), o and p represent integers of 1 to 1,000. R5 and R6 each independently represent a hydrogen atom, a linear, branched, or cyclic alkyl group having from 1 to 18 carbon atoms, a linear, branched, or cyclic alkoxyl group having from 1 to 30 carbon atoms, an aryl group having from 6 to 30 carbon atoms, or an aryloxy group having from 6 to 30 carbon atoms. X represents a divalent bridging group.) In the above general formula (4), examples of the alkyl group include a methyl group and an ethyl group. Examples of the alkoxy group include a methoxy group and an ethoxy group. Examples of the aryl group include a phenyl group. Examples of the aryloxy group include a phenyloxy group.

[0049] In the above general formula (4), X represents a divalent crosslinking group, and examples of the crosslinking group include a dialkoxybenzene group (o-dialkoxybenzene group, m-dialkoxybenzene group, p-dialkoxybenzene group) represented by the structure -O-C6H4-O-, and a bisphenylene group represented by the following general formula (5).The above divalent crosslinking groups can be used alone or in combination of two or more.The above crosslinked phosphazene compound can be obtained by the method described in JP-A-2003-192792 or other known methods.

[0050] [ka]

[0051] (In general formula (5), A represents a direct bond, —C(CH)—, —SO—, —S—, or —O—.) (C) The phosphazene compound may be synthesized or commercially available. Phosphazene compounds can be synthesized by known methods, such as those described in "Synthesis and Applications of Phosphazene Compounds" (by Kajiwara Naruyuki, CMC Publishing, 1986). For example, phosphazene compounds can be synthesized by reacting phosphorus pentachloride or phosphorus trichloride as a phosphorus source with ammonium chloride or ammonia gas as a nitrogen source by a known method (the cyclic product may be purified), and then substituting the resulting substance with an alcohol, phenol, and amines. Commercially available products, such as "Lavitor" (registered trademark) FP-110 manufactured by Fushimi Pharmaceutical Co., Ltd., are preferably used.

[0052] In the present invention, the blending amount of the phosphazene compound (C) is 0.1 to 10 parts by weight per 100 parts by weight of the thermoplastic polyester resin (A) from the viewpoint of a balance between flame retardancy, hydrolysis resistance, and tracking resistance. If the blending amount of the component (C) is less than 0.1 part by weight, the flame retardancy, hydrolysis resistance, and tracking resistance will decrease. It is more preferably 1 part by weight or more, even more preferably 2 parts by weight or more, and most preferably 4 parts by weight or more. On the other hand, if the blending amount of the component (C) exceeds 10 parts by weight, bleed-out will easily occur. It is more preferably 9 parts by weight or less, even more preferably 8 parts by weight or less.

[0053] The content of the (C) phosphazene compound in 100% by mass of the thermoplastic polyester resin composition is preferably 1% by mass or more and less than 5% by mass. If it is less than 5% by mass, a material with an excellent balance of flame retardancy, hydrolysis resistance, tracking resistance, and bleed-out can be obtained. More preferably, it is 1% by mass or more and 4.0% by mass or less, and even more preferably 1.5% by mass or more and 3.6% by mass or less.

[0054] The thermoplastic polyester resin composition of the present invention further contains (D) a nitrogen-based flame retardant to improve flame retardancy and tracking resistance. Examples of (D) nitrogen-based flame retardants in the present invention include aliphatic amine compounds, aromatic amine compounds, nitrogen-containing heterocyclic compounds, cyanide compounds, aliphatic amide compounds, aromatic amide compounds, urea, and thiourea. Two or more of these may be blended. Among these, nitrogen-containing heterocyclic compounds are preferred. In this case, a flame retardant containing both a nitrogen atom and a phosphorus atom is treated as a (C) phosphazene compound if it has a -P=N- bond in the molecule, and as a nitrogen-based flame retardant if it does not.

[0055] Examples of the aliphatic amine compound include ethylamine, butylamine, diethylamine, ethylenediamine, butylenediamine, triethylenetetramine, 1,2-diaminocyclohexane, and 1,2-diaminocyclooctane.

[0056] Examples of the aromatic amine compound include aniline and phenylenediamine.

[0057] Examples of the nitrogen-containing heterocyclic compounds include uric acid, adenine, guanine, 2,6-diaminopurine, 2,4,6-triaminopyridine, and triazine compounds.

[0058] The cyanide compound may include dicyandiamide.

[0059] Examples of the aliphatic amide compounds and aromatic amide compounds include N,N-dimethylacetamide and N,N-diphenylacetamide.

[0060] The triazine compounds exemplified as the nitrogen-containing heterocyclic compounds are compounds having a triazine skeleton, such as triazine, melamine, benzoguanamine, methylguanamine, cyanuric acid, melamine cyanurate, melamine isocyanurate, trimethyltriazine, triphenyltriazine, ameline, amelide, thiocyanuric acid, diaminomercaptotriazine, diaminomethyltriazine, diaminophenyltriazine, diaminoisopropoxytriazine, and melamine polyphosphate, with melamine cyanurate, melamine isocyanurate, and melamine polyphosphate being preferred.

[0061] The melamine cyanurate or melamine isocyanurate is preferably an adduct of cyanuric acid or isocyanuric acid with a triazine compound, typically in a molar ratio of 1:1, sometimes 1:2. These are produced by known methods, typically in powder form, by, for example, preparing a water slurry of a mixture of melamine and cyanuric acid or isocyanuric acid, thoroughly mixing the mixture to form fine salts of the two compounds, and then filtering and drying the slurry. The salts do not need to be completely pure; some unreacted melamine, cyanuric acid, or isocyanuric acid may remain. If dispersibility is poor, dispersants such as tris(β-hydroxyethyl)isocyanurate or known surface treatment agents such as polyvinyl alcohol and metal oxides such as silica may be used in combination. The average particle size of the melamine cyanurate or melamine isocyanurate before and after incorporation into a resin is preferably 0.1 to 100 μm from the viewpoints of flame retardancy, mechanical strength, and surface smoothness of the molded product. Here, the average particle size is the average particle size measured at 50% cumulative distribution particle size by the laser micron sizer method. Commercially available melamine cyanurate or melamine isocyanurate products such as MC-4000, MC-4500, and MC-6000 manufactured by Nissan Chemical Industries, Ltd. are preferably used.

[0062] The blending amount of the (D) nitrogen-based flame retardant is 0.1 to 50 parts by weight per 100 parts by weight of the (A) thermoplastic polyester resin, from the viewpoint of the balance between flame retardancy and toughness. If the blending amount of the (D) component is less than 0.1 part by weight, the flame retardancy will be insufficient. It is more preferably 1 part by weight or more, even more preferably 10 parts by weight or more, and most preferably 15 parts by weight or more. On the other hand, if the blending amount of the (D) component exceeds 50 parts by weight, the mechanical properties will deteriorate. It is preferably 40 parts by weight or less, and more preferably 30 parts by weight or less.

[0063] The thermoplastic polyester resin composition of the present invention further contains (E) a polyfunctional epoxy compound to improve hydrolysis resistance. By adding (E) a polyfunctional epoxy compound, the carboxyl groups of (A) the thermoplastic polyester resin are blocked by reaction, thereby suppressing hydrolysis reactions under high-temperature and high-humidity environments.

[0064] The polyfunctional epoxy compound (E) used in the present invention is a compound having two or more epoxy groups in one molecule and not containing a bromine atom. Examples of the polyfunctional epoxy compound include, but are not limited to, glycidyl ester compounds, glycidyl ether compounds, epoxidized fatty acid ester compounds, glycidyl imide compounds, and alicyclic epoxy compounds. Two or more of these compounds may be used in combination.

[0065] The glycidyl ether compound is a compound having a glycidyl ether structure, and examples thereof include condensation products of phenol compounds and epichlorohydrin, novolac type epoxy, and glycidyl ethers of polyvalent hydroxyl group compounds.

[0066] Specific examples of the condensation products of a phenol compound and epichlorohydrin include condensations products obtained by condensing a phenol compound such as bisphenol A, resorcinol, hydroquinone, pyrocatechol, bisphenol F, saligenin, bisphenol S, 4,4'-dihydroxybiphenyl, 1,5-dihydroxynaphthalene, 1,4-dihydroanthracene-9,10-diol, 6-hydroxy-2-naphthoic acid, 1,1-methylenebis-2,7-dihydroxynaphthalene, 1,1,2,2-tetrakis-4-hydroxyphenylethane, and cashew phenol with epichlorohydrin.

[0067] Specific examples of novolac type epoxies include phenol novolac type epoxies, cresol novolac type epoxies, naphthol novolac type epoxies, bisphenol A novolac type epoxies, dicyclopentadiene-phenol adduct novolac type epoxies, dimethylenephenylene-phenol adduct novolac type epoxies, and dimethylenebiphenylene-phenol adduct novolac type epoxies.

[0068] In the present invention, the polyhydric hydroxyl group compound refers to an aliphatic compound having two or more hydroxyl groups, and specific examples thereof include glycols having 2 to 20 carbon atoms, glycerin, polyglycerin, dipentaerythritol, tripentaerythritol, xylitol, mannitol, sorbitol, galactose, maltitol, lactitol, isomalt, inositol, glucose, and fructose.

[0069] In the present invention, the epoxidized fatty acid ester compound refers to a compound in which the unsaturated bond of an unsaturated fatty acid ester such as soybean oil or linseed oil has been epoxidized, and specific examples thereof include epoxidized fatty acid octyl ester, epoxidized soybean oil, and epoxidized linseed oil.

[0070] Specific 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-bromophthalimide. Examples of suitable glycidyl succinimide include N-glycidyl succinimide, N-glycidyl hexahydrophthalimide, N-glycidyl-1,2,3,6-tetrahydrophthalimide, N-glycidyl maleinimide, N-glycidyl-α,β-dimethylsuccinimide, N-glycidyl-α-ethylsuccinimide, N-glycidyl-α-propylsuccinimide, triglycidyl isocyanurate, N-glycidyl benzamide, N-glycidyl-p-methylbenzamide, N-glycidyl naphthamide, and N-glycidyl steramide.

[0071] Specific 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 imide, N-ethyl-4,5-epoxycyclohexane-1,2-dicarboxylic imide, N-phenyl-4,5-epoxycyclohexane-1,2-dicarboxylic imide, N-naphthyl-4,5-epoxycyclohexane-1,2-dicarboxylic imide, and N-tolyl-3-methyl-4,5-epoxycyclohexane-1,2-dicarboxylic imide.

[0072] The (E) polyfunctional epoxy compound is preferably at least one selected from glycidyl ether compounds, epoxidized fatty acid ester compounds, and alicyclic epoxy compounds, because it can suppress reactions between epoxy groups and prevent deterioration of retention stability. Among these, glycidyl ether compounds and epoxidized fatty acid ester compounds are more preferred. Among these, glycidyl ether compounds are even more preferred because they can further improve hydrolysis resistance. Furthermore, among glycidyl ether compounds, novolac-type epoxies are preferred because they can improve heat resistance, and dicyclopentadiene-phenol adduct novolac-type epoxies are particularly preferred.

[0073] Furthermore, the (E) polyfunctional epoxy compound is preferably an epoxy compound having an epoxy equivalent of 100 to 3000 g / eq. When the (E) polyfunctional epoxy compound has an epoxy equivalent of 100 g / eq or more, the amount of gas generated during melt processing can be suppressed. 150 g / eq or more is more preferable. When the (E) polyfunctional epoxy compound has an epoxy equivalent of 3000 g / eq or less, both long-term hydrolysis resistance and high-temperature melt retention stability can be achieved at higher levels. 2000 g / eq or less is even more preferable.

[0074] In the present invention, the blending amount of the (E) polyfunctional epoxy compound is 0.1 to 10 parts by weight per 100 parts by weight of the (A) thermoplastic polyester resin. If the blending amount of the (E) component is less than 0.1 part by weight, the effect of improving long-term hydrolysis resistance cannot be obtained. It is more preferably 0.3 parts by weight or more, and even more preferably 0.5 parts by weight or more. On the other hand, if the blending amount of the (E) component exceeds 10 parts by weight, heat resistance and retention stability tend to deteriorate. It is more preferably 7.5 parts by weight or less, and even more preferably 5 parts by weight or less.

[0075] In the present invention, the preferred range of the blending amount of the (E) polyfunctional epoxy compound can be set depending on the epoxy equivalent of the (E) polyfunctional epoxy compound. For example, the ratio of the amount of epoxy groups derived from the (E) polyfunctional epoxy compound blended into the thermoplastic polyester resin composition to the amount of carboxyl groups derived from the (A) thermoplastic polyester resin blended into the thermoplastic polyester resin composition (epoxy group blending amount (eq / g) / carboxyl group blending amount (eq / g)) is preferably 0.5 to 8. When the (epoxy group blending amount (eq / g) / carboxyl group blending amount (eq / g)) is 0.5 or more, long-term hydrolysis resistance can be further improved. It is preferably 1 or more, more preferably 2 or more. When the (epoxy group blending amount (eq / g) / carboxyl group blending amount (eq / g)) is 8 or less, retention stability, heat resistance, and mechanical properties can be simultaneously achieved at higher levels. It is preferably 7 or less, more preferably 6 or less.

[0076] In the present invention, the amount of carboxyl groups derived from the thermoplastic polyester resin (A) blended into the thermoplastic polyester resin composition can be determined from the carboxyl group concentration of the thermoplastic polyester resin (A) and the blending ratio of the component (A) in the entire thermoplastic polyester resin composition. The carboxyl group concentration of the thermoplastic polyester resin (A) can be calculated by titrating a solution of the thermoplastic polyester resin (A) dissolved in an o-cresol / chloroform (2 / 1, vol / vol) mixed solution with 0.05 mol / L ethanolic potassium hydroxide using 1% bromophenol blue as an indicator.

[0077] The thermoplastic polyester resin composition of the present invention further contains an olefin resin (F), which can further improve the mechanical properties and tracking resistance.

[0078] (F) Olefin resin is a thermoplastic resin obtained by polymerizing or copolymerizing olefins such as ethylene, propylene, butene, isoprene, and pentene. Specific examples include homopolymers such as polyethylene, polypropylene, polystyrene, poly-1-butene, poly-1-pentene, and polymethylpentene, ethylene / propylene copolymers, ethylene / propylene / non-conjugated diene copolymers, ethylene-butene-1 copolymers, ethylene / glycidyl methacrylate copolymers, ethylene / butene-1 / glycidyl methacrylate copolymers, ethylene / propylene / glycidyl methacrylate copolymers, ethylene / octene-1 / glycidyl methacrylate copolymers, ethylene / acrylic ester / glycidyl methacrylate copolymers, ethylene / maleic anhydride copolymers, ethylene / butene-1 / maleic anhydride copolymers, ethylene / propylene / maleic anhydride copolymers, and ethylene / acrylic ester / maleic anhydride copolymers. These (F) olefin resins may be used alone or in combination of two or more.

[0079] The (F) olefin resin preferably contains at least an acid-modified olefin resin, because it has excellent dispersibility in the (A) thermoplastic polyester resin, and excellent hydrolysis resistance and toughness. The acid-modified olefin resin is a modified olefin resin in which an acidic substrate has been introduced into the main chain or side chain, and examples thereof include ethylene / maleic anhydride copolymer, ethylene / butene-1 / maleic anhydride copolymer, ethylene / propylene / maleic anhydride copolymer, and ethylene / acrylic acid ester / maleic anhydride copolymer. Among these, it is preferable to contain at least an ethylene / butene-1 / maleic anhydride copolymer, because it has excellent dispersibility in the (A) thermoplastic polyester resin, flame retardancy, and hydrolysis resistance.

[0080] The blending amount of (F) olefin resin is 0.1 to 20 parts by weight per 100 parts by weight of (A) thermoplastic polyester resin. Within this range, it is possible to improve hydrolysis resistance and tracking resistance while maintaining flame retardancy. If the blending amount is less than 0.1 part by weight, the effect of improving tracking resistance cannot be obtained. It is more preferably 2 parts by weight or more, even more preferably 3 parts by weight or more, and particularly preferably 4 parts by weight or more. On the other hand, if the blending amount exceeds 20 parts by weight, flame retardancy and mechanical properties tend to decrease, which is not preferable. It is more preferably 15 parts by weight or less, and even more preferably 10 parts by weight or less.

[0081] In the present invention, the ratio of parts by weight of the (B) phosphinate salts to parts by weight of the (C) phosphazene compound (parts by weight of the (B) component per 100 parts by weight of the (A) component / parts by weight of the (C) component per 100 parts by weight of the (A) component) is 2.0 to 8.0. Because the (B) component and the components resulting from its decomposition are acidic, when the (B) component is blended with the (A) thermoplastic polyester and the (E) polyfunctional epoxy compound, the (B) component accelerates the hydrolysis of the ester bonds in the (A) component, reducing mechanical strength and hydrolysis resistance. Furthermore, the (B) component ring-opens the epoxy groups in the (E) component, significantly reducing the (E) component's ability to block the reaction of the carboxyl groups in the (A) component. As a result, the inclusion of the (E) component does not improve hydrolysis resistance. However, by blending the (B) phosphinate salts to the (C) phosphazene compound in a ratio of 2.0 to 8.0, the effects of the acid derived from the (B) component can be suppressed. This is because component (C) is a compound that does not easily generate acidic components, and at the blending ratio described above, the basicity of the -P=N- bond in component (C) can efficiently capture the acid components derived from component (B).

[0082] Component (C) is a compound that is unlikely to generate acidic components, but has low flame retardancy. Combining it with the highly flame-retardant component (B) can enhance flame retardancy. However, only by adjusting the weight ratio of component (B) to component (C) to 2.0 to 8.0 and incorporating components (E) and (F) can a resin composition be obtained that maintains flame retardancy while exhibiting a well-balanced combination of high levels of mechanical properties, hydrolysis resistance, tracking resistance, and metal corrosion resistance. A ratio greater than 8.0 results in decreased hydrolysis resistance, metal corrosion resistance, and tracking resistance. A more preferred range is 2.2 to 7.7, even more preferably 2.5 to 7.5, particularly preferably 3.0 to 7.0, and most preferably 3.2 to 5.2.

[0083] The thermoplastic polyester resin composition of the present invention preferably contains 30 to 65 mass% of the (B) at least one phosphinate selected from phosphinates and diphosphinates, 5 to 40 mass% of the (C) phosphazene compound, and 30 to 65 mass% of the (D) nitrogen-based flame retardant, where the total amount of the (B) at least one phosphinate selected from phosphinates and diphosphinates, the (C) phosphazene compound, and the (D) nitrogen-based flame retardant is taken as 100 mass%. While the (B), (C), and (D) components used in the present invention contribute to improving the flame retardancy of the resulting thermoplastic polyester resin composition, they can also cause deterioration in mechanical properties and hydrolysis resistance. Blending the (B), (C), and (D) components in the above-mentioned ranges is preferred because the resulting thermoplastic polyester resin composition maintains high flame retardancy while exhibiting excellent mechanical properties and hydrolysis resistance.

[0084] When the total amount of (B) at least one phosphinate selected from phosphinates and diphosphinates, (C) the phosphazene compound, and (D) the nitrogen-based flame retardant is taken as 100% by mass, the amount of (B) the phosphinate is preferably 34% by mass or more, and even more preferably 36% by mass or more, from the viewpoint of flame retardancy. On the other hand, from the viewpoints of mechanical properties and hydrolysis resistance, it is more preferably 62% by mass or less, and even more preferably 58% by mass or less. On the other hand, from the viewpoints of hydrolysis resistance, the amount of (C) the phosphazene compound is more preferably 6% by mass or more, and even more preferably 8% by mass or more. On the other hand, from the viewpoints of suppressing bleed-out and gas generation, it is more preferably 34% by mass or less, and even more preferably 30% by mass or less. On the viewpoints of flame retardancy, it is more preferably 32% by mass or more, and even more preferably 34% by mass or more, from the viewpoint of flame retardancy. On the other hand, from the viewpoint of mechanical properties, it is more preferably 60% by mass or less, and even more preferably 56% by mass or less.

[0085] The thermoplastic polyester resin composition of the present invention preferably further contains (G) an anti-metal corrosion agent. The (G) anti-metal corrosion agent of the present invention is a compound containing a structure represented by the following formula (6). By having such a structure, it is possible to further improve metal corrosion resistance and further reduce the amount of gas generated from the thermoplastic polyester resin composition during retention.

[0086] [ka]

[0087] (Y represents a heterocyclic group having a nitrogen atom).

[0088] Y may be any heterocyclic group containing a nitrogen atom, and the ring-constituting atoms may include, in addition to the nitrogen atom, one or more atoms selected from carbon, oxygen, and sulfur atoms. From the viewpoint of excellent mechanical properties, metal corrosivity, melt retention stability, fluidity, and flame retardancy, the number of atoms constituting the ring is preferably 3 to 14, and more preferably 5 to 7. Furthermore, the ring may be any of a saturated ring, a partially unsaturated ring, and an aromatic ring group, and the ring constituting the ring may be either a monocyclic ring or a fused ring. From the viewpoint of excellent mechanical properties, metal corrosivity, melt retention stability, fluidity, and flame retardancy, the monocyclic ring is preferred, and the ring structure is preferably a 3- to 14-membered ring, more preferably a 4- to 7-membered ring, even more preferably a 5- or 6-membered ring, and most preferably a 5-membered ring.

[0089] Specific examples of Y include a pyrrolyl group, an imidazolyl group, a benzimidazolyl group, an imidazolidinyl group, a pyrazolyl group, a pyrazolidinyl group, a triazolyl group, a tetrazolyl group, an oxazolyl group, an isoxazolyl group, a furazanyl group, a thiazolyl group, an isothiazolyl group, a pyridyl group, a pyridinyl group, a pyridazinyl group, a pyrimidinyl group, a pyrazinyl group, a pyrrolidinyl group, a piperidinyl group, a piperazinyl group, a morpholinyl group, an indolyl group, an indolinyl group, an isoindolyl group, an isoindolinyl group, an indolizinyl group, an indazolyl group, a quinolinyl group, an isoquinolinyl group, a quinolidinyl group, a quinoxalinyl group, a cinnolinyl group, a phthalazinyl group, and a carbazolyl group. In view of excellent mechanical properties, corrosion resistance to metals, melt retention stability, etc., a pyrrolyl group, an imidazolyl group, a benzimidazolyl group, an imidazolidinyl group, a pyrazolyl group, a pyrazolidinyl group, a triazolyl group, and a tetrazolyl group are preferred, and a triazolyl group is more preferred.

[0090] Specific examples of (G) anti-metal corrosion agents include compounds represented by the following chemical structural formula (7).

[0091] [ka]

[0092] An example of a commercially available product of the compound represented by chemical structural formula (7) is CDA-1 from ADEKA Corporation. The same company also commercially sells CDA-1M, which is composed of CDA-1 and an organic compound, and either can be preferably used.

[0093] In the present invention, the blending amount of (G) anti-metal corrosion agent is preferably 0.001 to 0.5 parts by weight, more preferably 0.01 to 0.3 parts by weight, and even more preferably 0.05 to 0.2 parts by weight, per 100 parts by weight of (A) thermoplastic polyester resin. When the blending amount is 0.001 part by weight or more, the corrosiveness to metals is improved, and when the blending amount is 0.5 part by weight or less, excellent mechanical strength can be achieved and high flame retardancy can be maintained.

[0094] The thermoplastic polyester resin composition of the present invention preferably contains a (H) retention stability improver. The (H) retention stability improver of the present invention is a compound having a structure represented by the following formula (8), i.e., a structure in which two or more oxygen atoms are bonded to a phosphorus atom having an unshared electron pair. By having such a structure, crosslinking reactions between the (E) polyfunctional epoxy compounds can be suppressed, and retention stability can be further improved at high temperatures of 270°C or higher. In general phosphorus compounds, the upper limit of the number of oxygen atoms that can be bonded to the phosphorus atom having an unshared electron pair from the valence of the phosphorus atom is three.

[0095] [ka]

[0096] Examples of the (H) retention stability improver used in the present invention include phosphonite compounds, which are compounds containing a structure in which two oxygen atoms are bonded to a phosphorus atom having an unshared electron pair, and phosphite compounds, which are compounds containing a structure in which three oxygen atoms are bonded to a phosphorus atom having an unshared electron pair.

[0097] Examples of phosphonite compounds include condensates of phosphonous acid compounds such as phenylphosphonous acid and 4,4'-biphenylenediphosphonous acid with aliphatic alcohols having 4 to 25 carbon atoms and / or phenolic compounds such as 2,6-di-t-butylphenol and 2,4-di-t-butyl-5-methylphenol. Specific examples include bis(2,4-di-t-butyl-5-methylphenyl)-phenylphosphonite, tetrakis(2,4-di-t-butyl-5-methylphenyl)-4,4'-biphenylenediphosphonite, and tetrakis(2,4-di-t-butylphenyl)-4,4'-biphenylenediphosphonite. Two or more of these may be used.

[0098] Examples of phosphite compounds include condensation products of phosphorous acid with aliphatic alcohols having 4 to 25 carbon atoms, polyhydric alcohols such as glycerol and pentaerythritol, and / or phenolic compounds such as 2,6-di-t-butylphenol and 2,4-di-t-butylphenol. Specifically, tris(alkylaryl)phosphites such as triisodecyl phosphite, trisnonylphenyl phosphite, diphenylisodecyl phosphite, phenyldiisodecyl phosphite, 2,2-methylenebis(4,6-di-t-butylphenyl)octyl phosphite, 4,4'-butylidenebis(3-methyl-6-t-butylphenyl)ditridecyl phosphite, tris(2,4-di-t-butylphenyl)phosphite, tris(2-t-butyl-4-methylphenyl)phosphite, tris(2,4-di-t-amylphenyl)phosphite, tris(2-t-butylphenyl)phosphite, tris[2-(1,1-dimethylpropyl)-phenyl]phosphite, and tris[2,4-(1,1-dimethylpropyl)-phenyl]phosphite (provided that In this case, the alkyl group is a branched alkyl group having 3 to 6 carbon atoms), bis(2-t-butylphenyl)phenyl phosphite, tris(2-cyclohexylphenyl)phosphite, tris(2-t-butyl-4-phenylphenyl)phosphite, bis(octyl)pentaerythritol diphosphite, bis(octadecyl)pentaerythritol diphosphite, bis(2,4-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite, bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite, bis(nonylphenyl)pentaerythritol diphosphite, and other bis(alkylaryl)pentaerythritol diphosphites (however, in this case, the alkyl group is an alkyl group having 3 to 9 carbon atoms). Two or more of these may be used.

[0099] From the viewpoint of heat resistance stability, the residence stability improver (H) preferably has a cyclic phosphite structure. A cyclic phosphite is a compound having a structural unit represented by the following formula (9) in the molecule, in which the phosphorus atom in the structural unit and two or more oxygen atoms bonded to it are contained in the ring. Specific examples include bis(alkylaryl)pentaerythritol diphosphites, such as bis(2,4-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite and bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite.

[0100] [ka]

[0101] In the present invention, the blending amount of the (H) retention stability improver is preferably 0.001 to 0.5 parts by weight per 100 parts by weight of the (A) thermoplastic polyester resin. By blending the (H) retention stability improver in an amount of 0.001 part by weight or more, retention stability can be improved. 0.01 part by weight or more is more preferred, and 0.05 part by weight or more is even more preferred. On the other hand, by blending the (H) retention stability improver in an amount of 0.5 parts by weight or less, long-term hydrolysis resistance and mechanical properties can be further improved. 0.4 parts by weight or less is more preferred, and 0.3 parts by weight or less is even more preferred.

[0102] The thermoplastic polyester resin composition of the present invention preferably further contains (I) a fibrous reinforcing material, which can further improve the mechanical strength and heat resistance.

[0103] Specific examples of the (I) fibrous reinforcing material include glass fiber, aramid fiber, and carbon fiber. The glass fiber may be a chopped strand type or a roving type. Glass fibers treated with a silane coupling agent such as an aminosilane compound or an epoxysilane compound and / or a sizing agent containing urethane, a copolymer of acrylic acid such as an acrylic acid / styrene copolymer, a copolymer of maleic anhydride such as a methyl acrylate / methyl methacrylate / maleic anhydride copolymer, vinyl acetate, bisphenol A diglycidyl ether, or one or more epoxy compounds such as a novolac epoxy compound are preferred. Glass fibers treated with a sizing agent containing a copolymer of maleic anhydride are more preferred because they can further improve hydrolysis resistance. The silane coupling agent and / or sizing agent may be mixed in an emulsion liquid before use. The fiber diameter of the glass fiber is generally preferably in the range of 1 to 30 μm. From the viewpoint of dispersibility of the glass fiber in the resin, the lower limit is preferably 5 μm. From the viewpoint of mechanical strength, the upper limit is preferably 15 μm. Furthermore, although the fiber cross section is usually circular, fibrous reinforcing materials having any cross section, such as oval glass fibers, flat glass fibers, and cocoon-shaped glass fibers with any aspect ratio, can also be used, which has the advantage of improving fluidity during injection molding and producing molded products with little warpage.

[0104] The blending amount of (I) fibrous reinforcing material is preferably 1 to 100 parts by weight per 100 parts by weight of (A) thermoplastic polyester resin. Blending 1 part by weight or more of (I) fibrous reinforcing material can further improve mechanical strength and heat resistance. Blending 2 parts by weight or more is more preferable, and 3 parts by weight or more is even more preferable. Blending 100 parts by weight or less of (I) fibrous reinforcing material can further improve mechanical strength and fluidity. Blending 95 parts by weight or less is more preferable, and 90 parts by weight or less is even more preferable.

[0105] The preferred range of the blending amount of (I) fibrous reinforcing material can also be set as its content in the thermoplastic polyester resin composition. The content of (I) fibrous reinforcing material in the thermoplastic polyester resin composition is preferably 1 to 70 parts by weight per 100 parts by weight of the thermoplastic polyester resin composition. By blending 1 part by weight or more of (I) fibrous reinforcing material per 100 parts by weight of the thermoplastic polyester resin composition, mechanical strength and heat resistance can be further improved. 3 parts by weight or more is more preferred, and 5 parts by weight or more is even more preferred. On the other hand, by blending 70 parts by weight or less of (I) fibrous reinforcing material per 100 parts by weight of the thermoplastic polyester resin composition, mechanical strength and flowability can be further improved. 60 parts by weight or less is more preferred, and 55 parts by weight or less is even more preferred.

[0106] The thermoplastic polyester resin composition of the present invention preferably further contains (J) an anti-drip agent. In the present invention, the anti-drip agent is a compound that can suppress melting and dripping of the resin composition during combustion and further improve flame retardancy, and examples of such an agent include fluorine-based resins.

[0107] The fluorine-based resin is a resin containing fluorine in the substance molecule, and specific examples include polytetrafluoroethylene, polyhexafluoropropylene, (tetrafluoroethylene / hexafluoropropylene) copolymer, (tetrafluoroethylene / perfluoroalkyl vinyl ether) copolymer, (tetrafluoroethylene / ethylene) copolymer, (hexafluoropropylene / propylene) copolymer, polyvinylidene fluoride, (vinylidene fluoride / ethylene) copolymer, etc. Among them, polytetrafluoroethylene, (tetrafluoroethylene / perfluoroalkyl vinyl ether) copolymer, (tetrafluoroethylene / hexafluoropropylene) copolymer, (tetrafluoroethylene / ethylene) copolymer, and polyvinylidene fluoride are preferred, and polytetrafluoroethylene and (tetrafluoroethylene / ethylene) copolymer are particularly preferred.

[0108] In addition, from the viewpoint of the balance between flame retardancy and mechanical strength, the blending amount of the anti-drip agent is preferably 0.01 to 1 part by weight per 100 parts by weight of the (A) thermoplastic polyester resin. By blending the anti-drip agent in an amount of 0.01 part by weight or more, flame retardancy can be ensured. 0.03 parts by weight or more is more preferable, and 0.05 parts by weight or more is even more preferable. On the other hand, by blending the anti-drip agent in an amount of 1 part by weight or less, the fluidity of the thermoplastic resin composition can be maintained. 0.8 parts by weight or less is more preferable, and 0.6 parts by weight or less is even more preferable.

[0109] The resin composition of the present invention may contain one or more optional additives such as ultraviolet absorbers, light stabilizers, plasticizers, release agents, antistatic agents, carbon black, titanium oxide, and pigments and dyes of various colors, as long as the object of the present invention is not impaired.

[0110] The resin composition of the present invention may contain thermoplastic resins other than components (A) and (F) within the scope of the present invention, which can improve moldability, dimensional accuracy, molding shrinkage, toughness, etc. Examples of thermoplastic resins other than component (A) include polyamide resins, polyacetal resins, polyurethane resins, aromatic or aliphatic polyketone resins, polyphenylene sulfide resins, polyether ether ketone resins, polyimide resins, thermoplastic starch resins, polyurethane resins, aromatic polycarbonate resins, polyarylate resins, polysulfone resins, polyethersulfone resins, polyphenylene ether resins, poly-4-methylpentene-1, polyetherimide resins, cellulose acetate resins, and polyvinyl alcohol resins.

[0111] The resin composition of the present invention may contain a polyhydric alcohol compound (hereinafter, sometimes referred to as a "polyhydric alcohol compound") having three or four functional groups and containing one or more alkylene oxide units. The polyhydric alcohol compound may be a low molecular weight compound or a polymer. Examples of functional groups include hydroxyl groups, aldehyde groups, carboxylic acid groups, sulfo groups, amino groups, isocyanate groups, carbodiimide groups, oxazoline groups, oxazine groups, ester groups, amide groups, silanol groups, and silyl ether groups. Among these, it is preferable to have three or four identical or different functional groups. In particular, from the viewpoint of further improving fluidity, it is even more preferable to have three or four identical functional groups. Furthermore, it is particularly preferable to use a compound containing a propylene oxide unit as an alkylene oxide unit.

[0112] As an indicator of the hydrolysis resistance of molded articles made from the thermoplastic polyester resin composition, ASTM No. 1 dumbbell (1 / 8 inch thick) tensile property evaluation test pieces molded from the thermoplastic polyester resin composition of the present invention in accordance with ASTM D638 (2005) were used. The ratio of the tensile strength after 50 hours and after 100 hours of exposure in an atmosphere of 100% relative humidity and 121°C to the tensile strength before exposure was measured. This ratio is called the tensile strength retention: (tensile strength after exposure / tensile strength before exposure) x 100(%). To suppress the decrease in molecular weight due to hydrolysis of the thermoplastic polyester resin, the molded articles of the present invention preferably have tensile strength retentions of 60% or more and 40% or more after 50 hours and after 100 hours of exposure in an atmosphere of 100% relative humidity and 121°C, respectively. The tensile strength retention rates of less than 60% and less than 40% after 50 hours and 100 hours of exposure under these conditions, respectively, indicate that the hydrolysis of the polyester resin increases the number of carboxyl end groups, resulting in a decrease in molecular weight. The increase in carboxyl end groups due to hydrolysis of the main chain further accelerates the decrease in molecular weight of the polyester resin, resulting in a decrease in mechanical properties. The tensile strength retention rate after 50 hours of exposure in an atmosphere of 100% relative humidity and 121°C is preferably 65% ​​or more, more preferably 70% or more. Furthermore, the tensile strength retention rate after 100 hours of exposure in an atmosphere of 100% relative humidity and 121°C is preferably 45% or more, more preferably 50% or more. The closer the tensile strength retention rate after 50 hours and 100 hours of exposure in an atmosphere of 100% relative humidity and 121°C is to 100%, the more suppressed the decrease in molecular weight due to the progression of hydrolysis of the polyester resin is, indicating higher hydrolysis resistance.

[0113] Molded articles made from the thermoplastic polyester resin composition of the present invention preferably have a comparative tracking index of 400 V or higher in accordance with IEC 60112. IEC 60112 refers to the safety standard for tracking resistance revised in 2003 by the International Electrotechnical Commission (IEC). Measurements can be made in accordance with the comparative tracking index measurement method of IEC 60112:2003, using a 0.1% aqueous ammonium chloride solution as the electrolyte. This standard addresses tracking breakdown, which occurs when an electric field and contaminants (electrolytes) such as dust or dirt are generated on the resin surface, causing partial discharge. The resulting heat accelerates decomposition and carbonization of the resin, ultimately resulting in surface insulation breakdown and ignition due to local overheating. Resin materials used near electric fields, such as those in mechanical components, electrical and electronic components, or automotive parts, are required to have a high level of tracking resistance. A comparative tracking index of 500 V or higher is more preferred, with a comparative tracking index of 550 V or higher being even more preferred, and a comparative tracking index of 600 V or higher being most preferred.

[0114] The thermoplastic polyester resin composition of the present invention can be obtained, for example, by melt-kneading the components (A) to (F) and, if necessary, other components.

[0115] Examples of the melt-kneading method include a method in which component (A), component (B), component (C), component (D), component (E), component (F), and optionally component (G) and component (H), as well as various additives, are premixed, and the mixture is fed into an extruder or the like and thoroughly melt-kneaded; or a method in which a predetermined amount of each component is fed into an extruder or the like using a metering feeder such as a gravimetric feeder, and thoroughly melt-kneaded.

[0116] Examples of the premixing include dry blending and mixing using a mechanical mixer such as a tumbler, ribbon mixer, or Henschel mixer. (I) Fibrous reinforcing materials and inorganic fillers other than fibrous reinforcing materials may be added by installing a side feeder between the base and vent sections of a multi-screw extruder such as a twin-screw extruder. Liquid additives may be added using a plunger pump with a liquid addition nozzle installed between the base and vent sections of a multi-screw extruder such as a twin-screw extruder, or by supplying the additive from the base using a metering pump.

[0117] The thermoplastic polyester resin composition of the present invention is preferably pelletized before molding, for example, by using a single-screw extruder, twin-screw extruder, triple-screw extruder, conical extruder, or kneader-type mixer equipped with a "Unimelt" or "Dulmage" type screw, to extrude the composition in the form of strands, followed by cutting with a strand cutter.

[0118] The thermoplastic polyester resin composition of the present invention can be melt-molded to obtain films, fibers, and other molded articles in various shapes. Examples of melt-molding methods include injection molding, extrusion molding, and blow molding, with injection molding being particularly preferred.

[0119] In addition to the usual injection molding method, other known injection molding methods include gas-assisted molding, two-color molding, sandwich molding, in-mold molding, insert molding, and injection press molding, and any of these molding methods can be applied.

[0120] The molded article of the present invention can be used as a molded article for machine mechanism parts, electrical parts, electronic parts, and automobile parts, taking advantage of its excellent flame retardancy, tracking resistance, and long-term hydrolysis resistance. Furthermore, because the molded article of the present invention has excellent flame retardancy, tracking resistance, and long-term hydrolysis resistance, it is particularly useful as an electrical and electronic part for automobiles.

[0121] Specific examples of mechanical parts, electrical parts, electronic parts, and automotive parts include breakers, electromagnetic switches, focus cases, flyback transformers, molded parts for fixing units in copiers and printers, housings for general home electrical appliances and office equipment, variable capacitor case parts, various terminal boards, transformers, printed wiring boards, housings, terminal blocks, coil bobbins, connectors, relays, disk drive chassis, transformers, switch parts, outlet parts, motor parts, sockets, plugs, capacitors, various cases, resistors, electrical and electronic parts that incorporate metal terminals and conductors, computer-related parts, audio parts such as audio components, lighting parts, telegraph equipment-related parts, telephone equipment-related parts, air conditioner parts, home appliance parts such as VTRs and televisions, copier parts, facsimile parts, optical equipment parts, automotive ignition system parts, automotive connectors, and various automotive electrical parts. [Example]

[0122] Next, the effects of the thermoplastic polyester resin composition of the present invention will be specifically described with reference to examples. It should be noted that Example 18 should be read as Reference Example 1. The raw materials used in the examples and comparative examples are shown below. Here, % and parts all represent % by weight and parts by weight, and " / " in the resin names below indicates copolymerization.

[0123] (A) Thermoplastic polyester resin <a-1>Polybutylene terephthalate resin: Polybutylene terephthalate resin manufactured by Toray Industries, Inc., having a carboxyl group amount of 30 eq / t, was used. <a-2>Polyethylene terephthalate resin: A polyethylene terephthalate resin manufactured by Toray Industries, Inc., having a carboxyl group amount of 40 eq / t, was used.

[0124] (B) Phosphinates <b-1>Aluminum diethylphosphinate: "Exolit" (registered trademark) OP-1240 manufactured by Clariant Japan K.K. was used.

[0125] (C) Phosphazene Compounds <c-1>Phosphonitrilic acid phenyl ester: "Lavitor" (registered trademark) FP-110 manufactured by Fushimi Pharmaceutical Co., Ltd. was used.

[0126] (C') Flame retardants not falling under (C) <C’-1> Ethylenediamine zinc phosphate: "Firecut" (registered trademark) "ZPO-3" manufactured by Suzuhiro Chemical Co., Ltd. was used.

[0127] (D) Nitrogen-based flame retardants <d-1>Melamine cyanurate, MC-4000 (white powder with an average particle size of 10 μm) manufactured by Nissan Chemical Industries, Ltd. was used.

[0128] (E) Polyfunctional epoxy compound <e-1>Dicyclopentadiene-type novolac epoxy: "EPICLON" HP-7200H manufactured by DIC Corporation was used (epoxy equivalent: 275 g / eq). <e-2>Bisphenol A type epoxy: "jER" (registered trademark) 1004K manufactured by Mitsubishi Chemical Corporation was used (epoxy equivalent: 926 g / eq).

[0129] (F) Olefin resin <f-1>Acid-modified olefin resin: ethylene / butene-1 / maleic anhydride copolymer, "Tafmer" (registered trademark) MH-5020 manufactured by Mitsui Chemicals, Inc. was used. <f-2>Olefin resin: ethylene-butene-1 copolymer, "Tafmer" (registered trademark) A4085S manufactured by Mitsui Chemicals, Inc. was used.

[0130] (G) Metal corrosion resistant agent <g-1>The compound represented by the above formula (6): CDA-1M manufactured by ADEKA Corporation was used.

[0131] (H) Retention stability improver <h-1>Bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite: "ADEKA STAB" (registered trademark) PEP36 manufactured by ADEKA Corporation was used.

[0132] (I) Fibrous reinforcement <i-1>Glass fiber treated with a bundling agent containing an epoxy compound: glass fiber ECS03T-187 manufactured by Nippon Electric Glass Co., Ltd., with a cross-sectional diameter of 13 μm and a fiber length of 3 mm was used. (J) Anti-drip agent <j-1>The fluorine-based resin, polytetrafluoroethylene, "Teflon" (registered trademark) 6-J manufactured by DuPont-Mitsui Fluorochemicals Co., Ltd. was used.

[0133] [Method of measuring each characteristic] In the examples and comparative examples, the properties were evaluated by the following measurement methods.

[0134] (1) Mechanical properties (tensile strength and tensile elongation) Using a Nissei Plastics NEX1000 injection molding machine, ASTM No. 1 dumbbell (1 / 8-inch thick) tensile test specimens and mold-notched Izod test specimens were molded in accordance with ASTM D638 (2005) under molding cycle conditions of 260°C and 80°C for polybutylene terephthalate resin (Component A), or 280°C and 80°C for polyethylene terephthalate resin (Component A), with a total injection time and dwell time of 10 seconds and a cooling time of 10 seconds. Tensile strength and elongation at maximum tensile point (tensile elongation) were measured using the resulting test specimens according to ASTM D638 (2005). The values ​​were averaged from three measurements. Materials with higher tensile strength values ​​were considered to have superior mechanical strength, and materials with higher tensile elongation values ​​were considered to have superior toughness.

[0135] (2) Flame retardancy (combustion rank) Using a Nissei Plastic Industrial NEX1000 injection molding machine, 125mm x 13mm x 1.6mm thick combustion test specimens were obtained under the same injection molding conditions as those for the mechanical properties described in (1) above. The resulting combustion test specimens were evaluated for flame retardancy according to the evaluation criteria set forth in the UL94 vertical test. Flame retardancy is ranked in descending order of V-0 > V-1 > V-2. Materials that were poor in flammability and did not reach the V-2 rating above and did not meet the flame retardancy rankings listed above were deemed non-compliant.

[0136] (3) Tracking resistance (comparative tracking index) Using a Nissei Plastic Industrial Co., Ltd. NEX1000 injection molding machine, injection molding was performed under the same injection molding conditions as in (1) above to obtain a square plate measuring 80 mm x 80 mm x 3 mm thick. The comparative tracking index of the obtained square plate was measured using a 0.1% aqueous ammonium chloride solution as the electrolyte solution in accordance with the comparative tracking index measurement method of IEC60112:2003.

[0137] (4) Hydrolysis resistance (tensile strength retention rate) Using a Nissei Plastic Industrial Co., Ltd. NEX1000 injection molding machine, ASTM No. 1 dumbbell (1 / 8 inch thick) test pieces for evaluating tensile properties were molded in accordance with ASTM D638 (2005) under the same injection molding conditions as in (1) above. The resulting ASTM No. 1 dumbbells were placed in an Espec Corp. EHS-411 highly accelerated life testing machine set to a temperature and humidity of 121°C and 100% RH, and subjected to moist heat treatment for 50 and 100 hours. The maximum tensile strength of the molded pieces after moist heat treatment was measured under the same conditions as in (1) above, and the average of three measurements was calculated. The tensile strength retention was calculated from the maximum tensile strength after moist heat treatment and the maximum tensile strength of the untreated pieces using the following formula: Tensile strength retention rate (%) = (maximum tensile strength after moist heat treatment ÷ maximum tensile strength before moist heat treatment) × 100 Materials with a tensile strength retention rate of less than 60% after 50 hours of moist heat treatment and less than 40% after 100 hours of moist heat treatment were judged to have poor hydrolysis resistance, and materials with a higher tensile strength retention rate were judged to have better hydrolysis resistance.

[0138] (5) Bleed out Using a Nissei Plastic Industrial Co., Ltd. NEX1000 injection molding machine, 1 / 8 inch (approximately 3.2 mm) thick ASTM No. 1 dumbbell test pieces for bleedout evaluation were obtained under the same injection molding conditions as in (1) above. The obtained ASTM No. 1 dumbbells were placed in an Espec Corp. EHS-411 highly accelerated life testing machine set to a temperature and humidity of 121°C x 100% RH for 96 hours (4 days) and subjected to moist heat treatment. The appearance of the molded product after moist heat treatment was visually observed, and bleedout was evaluated according to the following criteria. A: No liquid or white powdery bleeding out is observed in the molded product. B: Liquid or white powdery bleeding out is observed in some or all parts of the molded product.

[0139] (6) Metal corrosion test using heat treatment at 270°C for 3 hours (metal corrosion test) Approximately 10 g of thermoplastic polyester resin composition pellets were placed in a 60 mm diameter glass Petri dish with a glass lid. A 25 mm diameter glass watch glass was placed on top of the pellets. A copper plate measuring 10 mm in length, 20 mm in width, and 1 mm in thickness was then placed on the glass watch glass, and the glass lid was then placed on top of the dish to form a sample. The sample was placed in a Tabai Espec Gear Oven GPHH-200 (controlled at 270°C) for 3 hours. After cooling to room temperature, the state of corrosion of the copper plate within the sample was visually observed. The copper plate corroded and turned green due to the development of verdigris, which is copper rust. Observation of this green discoloration was considered to indicate corrosion.

[0140] (7) Retention stability (rate of change in melt viscosity index) The melt viscosity index (melt flow index) of the thermoplastic polyester resin composition was measured in accordance with ASTM D1238 (1999) using a C501DOS thermoplasticizer manufactured by Toyo Seiki Co., Ltd., under conditions of a temperature of 270°C and a load of 5000 g. Furthermore, after the thermoplastic polyester resin composition was allowed to reside in a cylinder for 30 minutes, the melt viscosity index was measured under the same conditions, and the difference (% change) in the melt viscosity index before and after the residency relative to the melt viscosity index before the residency was determined. The calculated % change was an absolute value and was calculated as a positive value. A rate of change in the melt viscosity index of more than 50% was considered to indicate poor residency stability, and a smaller difference was considered to indicate excellent residency stability.

[0141] (8) Gas volume 10 g of the resin composition was weighed into an aluminum cup and placed in an ESPEC PHH202 hot air oven at atmospheric pressure at 270°C for 3 hours, after which the weight of the resin composition was determined. The ratio of the difference in the weight of the resin composition before and after the heat treatment to the weight of the resin composition before the heat treatment (gas amount (%)) was determined. If the gas amount exceeded 3%, it was determined that the amount of gas generated was large and that the moldability was poor. The smaller the gas amount, the better the moldability.

[0142] [Examples 1 to 25], [Comparative Examples 1 to 16] Using a co-rotating, vented twin-screw extruder (TEX-30α, manufactured by Japan Steel Works, Ltd.) with a screw diameter of 30 mm and an L / D ratio of 35, (A) thermoplastic polyester resin, (B) phosphinate salts, (C) phosphazene compounds, (D) nitrogen-based flame retardants, (E) multifunctional epoxy compounds, and (F) olefin resins, as needed, (G) anti-metal corrosion agents, (H) retention stability improvers, and other materials were mixed in the compositions shown in Tables 1 to 5 and added to the extruder's base feeder. (I) Fibrous reinforcing material was added using a side feeder installed between the base feeder and the vent. Furthermore, melt mixing was performed at a mixing temperature of 250°C when polybutylene terephthalate resin was used as component (A), or at a mixing temperature of 270°C when polyethylene terephthalate resin was used as component (A), with a screw rotation of 200 rpm. The mixture was extruded into strands, passed through a cooling bath, and pelletized using a strand cutter.

[0143] The obtained pellets were dried in a hot air dryer at a temperature of 110° C. for 6 hours, and then evaluated by the above-mentioned method. The results are shown in Tables 1 to 5.

[0144] The ratio of the parts by weight of the (B) phosphinate salts to the parts by weight of the (C) phosphazene compound (parts by weight of the (B) component per 100 parts by weight of the (A) component / parts by weight of the (C) component per 100 parts by weight of the (A) component) is expressed as "Requirement (i): (B) / (C)".

[0145] The content (mass %) of the phosphazene compound (C) relative to 100 mass % of the thermoplastic polyester resin composition was expressed as "content of the phosphazene compound (C)."

[0146] When the total amount of (B) phosphinates, (C) phosphazene compounds, and (D) nitrogen-based flame retardants is taken as 100% by mass, the respective contents (% by mass) of the (B) component, the (C) component, and the (D) component are expressed as "content of (B) in (B), (C), and (D)," "content of (C) in (B), (C), and (D)," and "content of (D) in (B), (C), and (D)."

[0147] The content (mass%) of (I) fibrous reinforcing material relative to 100 mass% of the thermoplastic polyester resin composition is expressed as "content of (I) fibrous reinforcing material."

[0148] [Table 1]

[0149] [Table 2]

[0150] [Table 3]

[0151] [Table 4]

[0152] [Table 5]

[0153] Comparison of the Examples and Comparative Examples revealed that by setting the blending amounts of the (B), (C), (D), (E), and (F) components within specific ranges relative to 100 parts by weight of the (A) thermoplastic polyester resin, a material with an excellent balance of mechanical properties, flame retardancy, tracking resistance, hydrolysis resistance, and metal corrosion resistance was obtained.

Claims

1. A thermoplastic polyester resin composition comprising, relative to 100 parts by weight of (A) a thermoplastic polyester resin, (B) 0.1 to 50 parts by weight of at least one phosphinate salt selected from phosphinates and diphosphinates, (C) 0.1 to 10 parts by weight of a phosphazene compound, (D) 15 to 50 parts by weight of a nitrogen-based flame retardant, (E) 0.1 to 10 parts by weight of a polyfunctional epoxy compound, and (F) 0.1 to 10 parts by weight of an olefin resin, and which satisfies the following requirement (i): (i) The ratio of parts by weight of the at least one phosphinate salt (B) selected from phosphinate salts and diphosphinate salts to parts by weight of the phosphazene compound (C) (parts by weight of component (B) per 100 parts by weight of component (A) / parts by weight of component (C) per 100 parts by weight of component (A)) is 2.0 to 8.

0.

2. 2. The thermoplastic polyester resin composition according to claim 1, wherein the content of the phosphazene compound (C) is 1% by mass or more and less than 5% by mass based on 100% by mass of the thermoplastic polyester resin composition.

3. 3. The thermoplastic polyester resin composition according to claim 1, wherein, when the total amount of the (B) at least one phosphinate selected from phosphinates and diphosphinates, the (C) phosphazene compound, and the (D) nitrogen-based flame retardant is taken as 100% by mass, the (B) at least one phosphinate selected from phosphinates and diphosphinates accounts for 30 to 65% by mass, the (C) phosphazene compound accounts for 5 to 40% by mass, and the (D) nitrogen-based flame retardant accounts for 30 to 65% by mass.

4. 4. The thermoplastic polyester resin composition according to claim 1, wherein the polyfunctional epoxy compound (E) contains at least a novolac epoxy.

5. 5. The thermoplastic polyester resin composition according to claim 1, wherein the olefin resin (F) comprises at least an olefin resin modified with an acid.

6. The thermoplastic polyester resin composition according to any one of claims 1 to 5, further comprising 0.001 to 0.5 parts by weight of (G) a metal corrosion resistant agent, based on 100 parts by weight of (A) the thermoplastic polyester resin.

7. 7. The thermoplastic polyester resin composition according to claim 1, further comprising 0.001 to 0.5 parts by weight of a residence stability improver (H) based on 100 parts by weight of the thermoplastic polyester resin (A).

8. 8. The thermoplastic polyester resin composition according to claim 1, further comprising 1 to 100 parts by weight of (I) a fibrous reinforcing material, based on 100 parts by weight of (A) the thermoplastic polyester resin.

9. 9. The thermoplastic polyester resin composition according to claim 1, further comprising 0.01 to 1 part by weight of an anti-drip agent (J) based on 100 parts by weight of the thermoplastic polyester resin (A).

10. The thermoplastic polyester resin composition according to any one of claims 1 to 9, wherein the thermoplastic polyester resin (A) is a polybutylene terephthalate resin.

11. The thermoplastic polyester resin composition according to any one of claims 1 to 10, wherein the ratios of tensile strength after 50 hours and after 100 hours of exposure in an atmosphere of 100% relative humidity and 121°C temperature to the tensile strength before exposure of an ASTM No. 1 dumbbell (1 / 8 inch thick) test piece for evaluating tensile properties molded in accordance with ASTM D638 (2005) (tensile strength retention (%) = ((tensile strength after exposure / tensile strength before exposure) × 100)) are 60% or more and 40% or more, respectively.

12. A molded article obtained by melt molding the thermoplastic polyester resin composition according to any one of claims 1 to 11.

13. 13. The molded article according to claim 12, which has a comparative tracking index according to IEC 60112 of 400 V or more.

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