Polyalkylene terephthalate resin composition and resin molded article

Abstract

A polyalkylene terephthalate resin composition containing a polyalkylene terephthalate resin (A), a carbodiimide compound (B), and an inorganic filler (C) that has been surface treated by a sizing agent containing an epoxy resin and a polymer that contains a structural unit derived from a carboxylic acid and / or a carboxylic anhydride, in which the polyalkylene terephthalate resin composition contains 0.4-10 mass parts of the carbodiimide compound (B) per 100 mass parts of the polyalkylene terephthalate resin (A).

Description

Technical Field

[0001] The present invention relates to a polyalkylene terephthalate resin composition and a resin molded product.

Background Art

[0002] Polyester resins (polyalkylene terephthalate resins) are excellent in mechanical properties, electrical properties, heat resistance, and moldability. In particular, by adding inorganic fillers such as glass fibers, the mechanical properties and heat resistance are improved, so they are widely used in various fields such as automotive parts, parts for electric and electronic devices, and parts for precision devices. On the other hand, since polyester resins have ester groups in the molecule, hydrolysis easily occurs in a high-temperature and high-humidity environment, and in automotive parts where environmental changes are large, improvement of hydrolysis resistance is always desired.

[0003] In order to improve the hydrolysis resistance of the polyester resin itself, it is generally known to add an epoxy resin or a carbodiimide compound to reduce the amount of terminal carboxyl groups (see Patent Documents 1 and 2).

[0004] Patent Document 1 shows that when the amount of terminal carboxyl groups in a resin composition composed of a polybutylene terephthalate resin having an amount of terminal carboxyl groups of 30 meq / kg or less, a carbodiimide compound, a fibrous filler, and an elastomer is set to 1, the amount of carbodiimide functional groups is 0.3 to 1.5 equivalents, the heat shock resistance and hydrolysis resistance are improved.

[0005] Patent Document 2 shows that the hydrolysis resistance is improved by blending an epoxy compound with polybutylene terephthalate having a terminal carboxyl group concentration of 0.1 μeq / g or more and less than 6 μeq / g and an intrinsic viscosity of 0.75 to 1 dL / g.

[0006] On the other hand, it is known that the hydrolysis resistance of glass fibers themselves can be improved by using epoxy resin as a sizing agent (see Patent Documents 3-4). Patent Document 3 shows the use of glass fibers surface-treated with a sizing agent that includes unsaturated carboxylic acids and / or copolymers of anhydrous unsaturated carboxylic acids and unsaturated monomers, and epoxy resin as essential components. Patent Document 4 also shows that surface-treated glass fibers containing novolac-type epoxy resin have excellent long-term heat resistance. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] International Publication No. 2009 / 150831 [Patent Document 2] Japanese Patent Publication No. 2004-277718 [Patent Document 3] Japanese Patent Publication No. 2003-201671 [Patent Document 4] Japanese Patent Publication No. 2015-129073 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] As mentioned above, although proposals have been made to improve the hydrolysis resistance of polyester resins, they are still insufficient, and further improvements are expected.

[0009] The present invention has been made in view of the above-mentioned conventional problems, and its objective is to provide a polyalkylene terephthalate resin composition and resin molded article reinforced with an inorganic filler, which has significantly improved hydrolysis resistance compared to conventional materials. [Means for solving the problem]

[0010] As a result of diligent research to solve the above-mentioned problems, the inventors of the present invention have found that by adding a carbodiimide compound to a polyalkylene terephthalate resin containing glass fibers surface-treated with a sizing agent containing a polymer with constituent units derived from carboxylic acids and the like and an epoxy resin, hydrolysis resistance is significantly improved compared to conventional methods, and have completed the present invention.

[0011] One embodiment of the present invention that solves the aforementioned problems is as follows. (1) Polyalkylene terephthalate resin (A), Carbodiimide compound (B), and The inorganic filler (C) is surface-treated with a sizing agent containing a polymer containing constituent units derived from carboxylic acids and / or carboxylic acid anhydrides and an epoxy resin, A polyalkylene terephthalate resin composition containing 0.4 to 10 parts by mass of the carbodiimide compound (B) per 100 parts by mass of the polyalkylene terephthalate resin (A).

[0012] (2) The polyalkylene terephthalate resin composition according to (1), wherein the carbodiimide compound (B) is an aromatic carbodiimide.

[0013] (3) The polyalkylene terephthalate resin composition according to (1) or (2), wherein the inorganic filler (C) is fibrous, has an average fiber diameter of 3 to 50 μm, and contains 0.4 to 3.0 parts by mass of the sizing agent per 100 parts by mass of the inorganic filler (C).

[0014] (4) A resin molded article obtained by molding the polyalkylene terephthalate resin composition described in (1) or (2) above. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a polyalkylene terephthalate resin composition and resin molded articles reinforced with inorganic fillers, which have significantly improved hydrolysis resistance compared to conventional materials. [Modes for carrying out the invention]

[0016] <Polyalkylene terephthalate resin composition> The polyalkylene terephthalate resin composition of this embodiment comprises a polyalkylene terephthalate resin (hereinafter also referred to as "PAT resin") (A), a carbodiimide compound (B), and an inorganic filler (C) surface-treated with a sizing agent containing a polymer comprising structural units derived from carboxylic acids and / or carboxylic acid anhydrides, and an epoxy resin. Furthermore, it contains 0.4 to 10 parts by mass of the carbodiimide compound (B) per 100 parts by mass of the polyalkylene terephthalate resin (A).

[0017] The PAT resin composition of this embodiment exhibits significantly improved hydrolysis resistance compared to conventional materials due to the combination of a carbodiimide compound (B) and an inorganic filler (C) surface-treated with a sizing agent containing a polymer with constituent units derived from carboxylic acids and / or carboxylic acid anhydrides, and an epoxy resin. In other words, the carbodiimide compound (B) and the inorganic filler (C) work together to contribute to improved hydrolysis resistance. The components of the polyalkylene terephthalate resin composition of this embodiment are described below.

[0018] [Polyalkylene terephthalate resin (A)] PAT resin (A) is a thermoplastic polyester resin obtained by the reaction of a dicarboxylic acid component mainly composed of a dicarboxylic acid compound and / or its ester-forming derivative, and a diol component mainly composed of a diol compound and / or its ester-forming derivative, wherein the dicarboxylic acid component mainly consists of terephthalic acid and / or its ester-forming derivative, and the diol component mainly consists of alkylene glycol and / or its ester-forming derivative. As a PAT resin, copolyesters can also be used, which are combinations of dicarboxylic acid components, diol components, and other copolymerizable monomers such as oxycarboxylic acid components and lactone components (hereinafter sometimes referred to as copolymerizable monomers).

[0019] Examples of dicarboxylic acid components other than the main components include aliphatic dicarboxylic acids (for example, dicarboxylic acids having about 4 to 40 carbon atoms such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, hexadecanedicarboxylic acid, dimer acid, preferably dicarboxylic acids having about 4 to 14 carbon atoms), alicyclic dicarboxylic acids (for example, dicarboxylic acids having about 4 to 40 carbon atoms such as hexahydrophthalic acid, hexahydroisophthalic acid, hexahydroterephthalic acid, hymic acid, preferably dicarboxylic acids having about 8 to 12 carbon atoms), aromatic dicarboxylic acids other than terephthalic acid (for example, naphthalenedicarboxylic acids such as phthalic acid, isophthalic acid, methylisophthalic acid, methylterephthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, 4,4'-diphenoxyetherdicarboxylic acid, 4,4'-dioxybenzoic acid, 4,4'-diphenylmethanedicarboxylic acid, 4,4'-diphenylketonedicarboxylic acid, etc., dicarboxylic acids having about 8 to 16 carbon atoms), or derivatives thereof (for example, ester-forming derivatives such as lower alkyl esters, aryl esters, acid anhydrides, etc.). Preferred dicarboxylic acid components for use in combination with terephthalic acid include isophthalic acid, naphthalenedicarboxylic acid, etc., and two or more of these can be used in combination. However, preferably 50 mol% or more, more preferably 80 mol% or more, and particularly preferably 90 mol% or more of the total dicarboxylic acid component as the copolymerizable monomer is an aromatic dicarboxylic acid compound. Further, if necessary, polyvalent carboxylic acids such as trimellitic acid and pyromellitic acid or their ester-forming derivatives (such as alcohol esters, etc.) may be used in combination. When such polyfunctional compounds are used in combination, branched PAT resins can also be obtained.

[0020] Examples of diol components other than the main component include aliphatic alkanediols (e.g., aliphatic diols having about C2-12 such as ethylene glycol, trimethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, neopentyl glycol, hexanediol, octanediol, decanediol, preferably aliphatic diols having about C2-10, excluding those used as the main component), polyoxyalkylene glycols (glycols having a plurality of oxyalkylene units of about C2-4, e.g., diethylene glycol, dipropylene glycol, ditetramethylene glycol, triethylene glycol, tripropylene glycol, polytetramethylene glycol, etc.), alicyclic diols (e.g., 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.), etc. Further, aromatic diols such as hydroquinone, resorcinol, bisphenol, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis-(4-(2-hydroxyethoxy)phenyl)propane, xylylene glycol, etc. may be used in combination. However, preferably 50 mol% or more, more preferably 80 mol% or more, and particularly preferably 90 mol% or more of the total diol component as the copolymerizable monomer is alkylene glycol. Further, if necessary, polyols such as glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, etc. or their ester-forming derivatives may be used in combination. By using such polyfunctional compounds in combination, a branched thermoplastic PAT resin can also be obtained.

[0021] Examples of the oxycarboxylic acid (or oxycarboxylic acid component or oxycarboxylic acids) include oxycarboxylic acids such as oxybenzoic acid, oxynaphthoic acid, hydroxyphenylacetic acid, glycolic acid, oxycaproic acid, etc. or their derivatives, etc. Examples of the lactone include C3-12 lactones such as propiolactone, butyrolactone, valerolactone, caprolactone (e.g., ε-caprolactone, etc.).

[0022] In copolyesters, the proportion of copolymerizable monomers can be selected from a range of, for example, 0.01 mol% to 30 mol%, and is usually 1 mol% to 25 mol%, preferably 3 mol% to 20 mol%, and more preferably 5 mol% to 15 mol%. When homopolyesters and copolyesters are used in combination, the ratio of homopolyesters to copolyesters is in a range where the proportion of copolymerizable monomers is 0.01 mol% to 30 mol% (preferably 1 mol% to 25 mol%, more preferably 3 mol% to 20 mol%, and particularly preferably 5 mol% to 15 mol%) relative to the total monomers, and is usually selected from a range of former / latter = 99 / 1 to 1 / 99 (mass ratio), preferably 95 / 5 to 5 / 95 (mass ratio), and more preferably 90 / 10 to 10 / 90 (mass ratio).

[0023] Preferred PAT resins include homopolyesters or copolyesters having alkylene terephthalate units as the main component (for example, 50 to 100 mol%, preferably 75 to 100 mol%). Examples include homopolyesters such as polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), and other poly-C2-4 alkylene terephthalates; copolyesters having alkylene terephthalate units as the main component and alkylene isophthalate units as the copolymer component; and copolyesters having alkylene terephthalate units as the main component and alkylene naphthalate units as the copolymer component. These can be used individually or in combination of two or more.

[0024] The amount of terminal carboxyl groups in the PAT resin is not particularly limited as long as it does not hinder the effect of the PAT resin composition of this embodiment. The amount of terminal carboxyl groups in the PAT resin is preferably 30 meq / kg or less, and more preferably 25 meq / kg or less. Too many terminal carboxyl groups in the PAT resin may impair hydrolysis resistance. Furthermore, in order to ensure adhesion with the inorganic filler surface-treated with a sizing agent, the amount of terminal carboxyl groups in the PAT resin is preferably 3 meq / kg or more, and more preferably 5 meq / kg or more.

[0025] The intrinsic viscosity (IV) of the PAT resin is not particularly limited as long as it does not hinder the effects of the PAT resin composition of this embodiment. From the viewpoint of moldability, the intrinsic viscosity of the PAT resin is preferably 0.6 to 1.3 dL / g, and more preferably 0.7 to 1.2 dL / g. When the intrinsic viscosity of the PAT resin is 0.7 to 1.0 dL / g, the resulting PAT resin composition has particularly excellent moldability. Furthermore, the intrinsic viscosity can be adjusted by blending PAT resins having different intrinsic viscosities. For example, by blending a PAT resin with an intrinsic viscosity of 0.69 dL / g and a PAT resin with an intrinsic viscosity of 0.88 dL / g, a PAT resin with an intrinsic viscosity of 0.78 dL / g can be prepared. The intrinsic viscosity (IV) of the PAT resin is the value measured in o-chlorophenol at a temperature of 35°C.

[0026] Furthermore, commercially available PAT resins may be used, or they may be manufactured by copolymerizing (polycondensing) a dicarboxylic acid component or its reactive derivative, a diol component or its reactive derivative, and a copolymerizable monomer as needed, using conventional methods such as transesterification or direct esterification.

[0027] [Carbodiimide compound (B)] In the PAT resin composition of this embodiment, the carbodiimide compound (B) plays a role in improving hydrolysis resistance. Carbodiimide compounds are compounds having a carbodiimide group (-N=C=N-) in their molecule. Examples of carbodiimide compounds include aliphatic carbodiimide compounds with an aliphatic main chain, alicyclic carbodiimide compounds with an alicyclic main chain, and aromatic carbodiimide compounds with an aromatic main chain. One or more selected from these can be used. In particular, it is preferable to include an aromatic carbodiimide compound in terms of the heat resistance and moisture resistance of the carbodiimide compound.

[0028] Examples of aliphatic carbodiimide compounds include diisopropylcarbodiimide and dioctyldecylcarbodiimide. Examples of alicyclic carbodiimide compounds include dicyclohexylcarbodiimide. Two or more of these can also be used in combination.

[0029] Aromatic carbodiimide compounds include diphenylcarbodiimide, di-2,6-dimethylphenylcarbodiimide, N-triyl-N'-phenylcarbodiimide, di-p-nitrophenylcarbodiimide, di-p-aminophenylcarbodiimide, di-p-hydroxyphenylcarbodiimide, di-p-chlorophenylcarbodiimide, di-p-methoxyphenylcarbodiimide, di-3,4-dichlorophenylcarbodiimide, di-2,5-dichlorophenylcarbodiimide, di-o-chlorophenylcarbodiimide, p-phenylene-bis-di-o-triylcarbodiimide, p-phenylene-bis-dicyclohexylcarbodiimide, p-phenylene-bis-di-p-chlorophenylcarbodiimide, and ethylene-bi Examples include mono- or dicarbodiimide compounds such as s-diphenylcarbodiimide; and polycarbodiimide compounds such as poly(4,4'-diphenylmethanecarbodiimide), poly(3,5'-dimethyl-4,4'-biphenylmethanecarbodiimide), poly(p-phenylenecarbodiimide), poly(m-phenylenecarbodiimide), poly(3,5'-dimethyl-4,4'-diphenylmethanecarbodiimide), poly(naphthylenecarbodiimide), poly(1,3-diisopropylphenylenecarbodiimide), poly(1-methyl-3,5-diisopropylphenylenecarbodiimide), poly(1,3,5-triethylphenylenecarbodiimide), and poly(triisopropylphenylenecarbodiimide). Two or more of these can also be used in combination.

[0030] The number-average molecular weight of the carbodiimide compound (B) is preferably 3000 or more. By keeping the number-average molecular weight within the above range, it is possible to prevent the generation of gases and odors when the residence time is long during the melt-kneading or molding of thermoplastic resins.

[0031] The content of carbodiimide compound (B) is 0.4 to 10 parts by mass per 100 parts by mass of PAT resin (A). If the content is less than 0.4 parts by mass, hydrolysis resistance cannot be improved, and if it exceeds 10 parts by mass, fluidity decreases and gel components and carbides are more likely to be formed during compounding (manufacturing of the resin composition) or molding. The content of carbodiimide compound (B) is preferably 0.5 to 7 parts by mass, and more preferably 0.5 to 3 parts by mass.

[0032] [Inorganic filler (C)] In the PAT resin composition of this embodiment, the inorganic filler (C) is surface-treated with a sizing agent containing a polymer containing constituent units derived from carboxylic acids and / or carboxylic acid anhydrides and an epoxy resin. The inclusion of an inorganic filler (C) improves the mechanical strength of the molded product, and furthermore, surface treatment with a predetermined sizing agent provides excellent hydrolysis resistance.

[0033] The shape of the inorganic filler (C) is not particularly limited, and either fibrous inorganic fillers or non-fibrous inorganic fillers can be used.

[0034] (Fibrous inorganic filler) Examples of fibrous inorganic fillers include glass fibers, carbon fibers, silica fibers, silica-alumina fibers, zirconia fibers, boron nitride fibers, silicon nitride fibers, boron fibers, potassium titanate fibers, and metal fibers (e.g., stainless steel, aluminum, titanium, copper, brass, etc.). Typical fibrous inorganic fillers include glass fibers and carbon fibers, with glass fibers being preferred due to their availability and cost-effectiveness. While there are no particular limitations on the type of glass used as the raw material for glass fibers, E-glass and corrosion-resistant glass containing zirconium in its composition are preferred for quality reasons.

[0035] The average fiber diameter of the fibrous inorganic filler is not particularly limited, but is preferably 3 to 50 μm, and more preferably 6 to 15 μm. The average fiber length of the fibrous inorganic filler is not particularly limited, and can be, for example, 0.1 to 20 mm. The average fiber diameter and average fiber length of the fibrous inorganic filler are values ​​calculated by analyzing images taken with a CCD camera of the fibrous inorganic filler before it is incorporated into the resin composition, and using a weighted average. For example, this can be calculated using a dynamic image analysis / particle (state) analyzer such as the PITA-3 manufactured by Seishin Corporation.

[0036] As fibrous inorganic fillers, those with a circular cross-section and those with a non-circular cross-section can both be used. Examples of non-circular cross-sections include oval, elliptical, and cocoon-shaped shapes. The ratio of the non-circular cross-section (major axis diameter:minor axis diameter) is not particularly limited, but is preferably 1.5:1 to 6:1, more preferably 2:1 to 5:1, and even more preferably 2.5:1 to 4:1. When the ratio of the non-circular cross-section is in the range of 1.5:1 to 6:1, it is easier to obtain effects such as dimensional stability and warping reduction due to the flattening of the cross-section, and it is also easier to suppress the decrease in strength due to excessive flattening which makes it prone to cracking.

[0037] (Non-fibrous inorganic filler) The shape of non-fibrous inorganic fillers is not particularly limited and can be granular, ellipsoidal, spindle-shaped, plate-shaped, flaky, or irregularly shaped. Specific examples of non-fibrous inorganic fillers include: silicates such as mica, talc, quartz, calcium silicate, aluminum silicate, kaolin, clay, diatomaceous earth, and bentonite; carbon-based materials such as carbon black and graphite; metal carbonates such as calcium carbonate and magnesium carbonate; metal sulfates such as zinc sulfate, calcium sulfate, and barium sulfate; metal oxides such as zinc oxide, iron oxide, titanium oxide, antimony trioxide, and alumina; glass flakes, glass beads, milled glass fibers, glass balloons, and glass powder; and other materials such as magnesium hydroxide, boehmite, spherical silica, ferrite, silicon carbide, silicon nitride, boron nitride, and various metal powders, but are not limited to these. From the viewpoint of improving low warping, it is preferable to include plate-like or flaky inorganic fillers such as mica, glass flakes, and talc, and it is more preferable to include at least plate-like inorganic fillers such as mica and talc.

[0038] The inorganic filler (C) may be used alone or in combination of two or more types.

[0039] Furthermore, fibrous inorganic fillers and non-fibrous inorganic fillers may be used in combination. By using fibrous inorganic fillers and non-fibrous inorganic fillers in combination, it is possible to achieve both low warping and mechanical properties such as tensile strength. The ratio of fibrous inorganic fillers to non-fibrous inorganic fillers is not particularly limited, but it is preferable that the fibrous inorganic filler / non-fibrous inorganic filler (mass ratio) = 80 / 20 to 45 / 55, more preferably 75 / 25 to 55 / 45, and even more preferably 70 / 30 to 60 / 40. If the content of non-fibrous inorganic fillers is 20% by mass or more of the inorganic fillers, better low warping is more likely to be obtained, and if it is 55% by mass or less, better tensile strength is more likely to be obtained. The combination of fibrous inorganic fillers and non-fibrous inorganic fillers is not particularly limited, but examples include a combination of fibrous inorganic fillers such as glass fibers and carbon fibers, and non-fibrous inorganic fillers such as glass flakes, mica, and talc, with the combination preferably containing at least glass fibers and mica.

[0040] Next, regarding inorganic fillers (C), polymers and epoxy resins having constituent units derived from carboxylic acids and / or carboxylic acid anhydrides, which are included in the sizing agent used for surface treatment, will be described below.

[0041] (polymers having constituent units derived from carboxylic acids and / or carboxylic acid anhydrides) Polymers having constituent units derived from carboxylic acids and / or carboxylic acid anhydrides (hereinafter also simply referred to as "polymers") include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, fumaric acid, maleic acid, succinic acid, cinnamic acid, itaconic acid, mesaconic acid, and citraconic acid. These may have substituents. Among these, acrylic acid, methacrylic acid, and maleic acid are preferred. Examples of carboxylic acid anhydrides include unsaturated carboxylic acid anhydrides such as maleic anhydride, itaconic anhydride, succinic anhydride, phthalic anhydride, glutaric anhydride, dodecenylsuccinic anhydride, and chlorendicic anhydride. The polymers described above may be homopolymers obtained by polymerizing each carboxylic acid or carboxylic anhydride individually, or they may be copolymers obtained by copolymerizing two or more carboxylic acids or carboxylic anhydrides.

[0042] In this embodiment, the weight-average molecular weight of the polymer is not particularly limited, but 10,000 to 1,000,000 is particularly preferred. When the weight-average molecular weight is within the range of 10,000 to 1,000,000, sufficient hydrolytic properties are obtained, and sufficient adhesion to the surface of the inorganic filler is achieved.

[0043] (Epoxy resin) Examples of epoxy resins include glycidyl ether type epoxy resins, glycidyl ester type epoxy resins (diglycidyl phthalate, diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, dimethylglycidyl phthalate, dimethylglycidyl hexahydrophthalate, dimer acid glycidyl ester, aromatic diglycidyl ester, cycloaliphatic diglycidyl ester, etc.), and glycidylamine type epoxy resins (tetraglycidyldiaminodiphenylmethane, triglycidyl-paraaminophenol, triglycidyl-methamine). Examples include nophenols, diglycidyl toluidine, tetraglycidyl metaxylylenediamine, diglycidyl tribromaniline, tetraglycidyl bisaminomethylcyclohexane, etc., heterocyclic epoxy resins (triglycidyl isocyanurate (TGIC), hydantoin-type epoxy resins, etc.), cyclic aliphatic epoxy resins (vinylcyclohexene dioxide, dicyclopentadiene oxide, alicyclic diepoxyacetal, alicyclic diepoxyadipate, alicyclic diepoxycarboxylate, etc.), and epoxidized polybutadiene.

[0044] Glycidyl ether type epoxy resins include glycidyl ethers of polyhydroxy compounds [such as bisphenol type epoxy resins (e.g., bisphenol A type, bisphenol AD ​​type, or bisphenol F type epoxy resins), glycidyl ethers of aromatic polyhydroxy compounds such as resorcinol type epoxy resins, and aliphatic epoxy resins (such as glycidyl ethers of alkylene glycols and polyoxyalkylene glycols)], and novolac type epoxy resins (such as phenol novolac type and cresol novolac type epoxy resins).

[0045] Among epoxy resins, aromatic epoxy resins (such as bisphenol-type epoxy resins, resorcinol-type epoxy resins, and phenol novolac-type epoxy resins) and cyclic aliphatic epoxy resins are preferred. In particular, glycidyl ether-type aromatic epoxy resins, such as bisphenol-type epoxy resins and phenol novolac-type epoxy resins, are preferred.

[0046] The epoxy equivalent of the epoxy resin may be, for example, 100 to 1600 g / eq, preferably 100 to 800 g / eq, and more preferably 150 to 500 g / eq.

[0047] The number-average molecular weight of the epoxy resin may be, for example, 200 to 50,000, preferably 300 to 10,000, and more preferably 400 to 6,000.

[0048] In this embodiment, the mass ratio (X / Y) of polymer (X) to epoxy resin (Y) in the sizing agent is not particularly limited, but is preferably 0.001 to 1.500.

[0049] The sizing agent is preferably contained in an amount of 0.1 to 5.0 parts by mass, and more preferably 0.3 to 4.0 parts by mass, per 100 parts by mass of the inorganic filler (C). By having a surface treatment agent content of 0.4 to 3.0 parts by mass, hydrolysis resistance can be improved.

[0050] In addition to the components mentioned above, the sizing agent may also contain other components such as urethane resin, silane coupling agent, lubricant, nonionic surfactant, and antistatic agent, and the mixing ratio of each component can be determined as needed. The urethane resin contributes to the binding and dispersibility of the glass fibers and is obtained from polyisocyanate and polyol, etc. The silane coupling agent is used to improve the interfacial adhesion between the glass fibers and the sizing agent. Suitable silane coupling agents include aminosilane, epoxysilane, chlorosilane, mercaptosilane, vinylsilane, and acrylicsilane. The lubricant is used to suppress wear caused by friction between the glass fibers. Suitable lubricants include fatty acid amides and quaternary ammonium salts. Suitable nonionic surfactants include synthetic alcohol-based, natural alcohol-based, and fatty acid ester-based surfactants.

[0051] In the PAT resin composition of this embodiment, the inorganic filler (C) is preferably contained in an amount of 10 to 100 parts by mass, and more preferably in an amount of 20 to 80 parts by mass, per 100 parts by mass of PAT resin.

[0052] [Other ingredients] The PAT resin composition of this embodiment may contain other components as needed. Examples of other components include, but are not limited to, inorganic fillers other than inorganic filler (C), antioxidants, weather stabilizers, molecular weight modifiers, ultraviolet absorbers, antistatic agents, dyes, pigments, lubricants, crystallization accelerators, crystal nucleating agents, near-infrared absorbers, flame retardants, flame retardant aids, organic fillers, and colorants.

[0053] <Resin molded products> The resin molded product of this embodiment is formed by molding the PAT resin composition of this embodiment described above. Therefore, similar to the PAT resin composition of this embodiment, it has the effect of significantly improving hydrolysis resistance compared to conventional products.

[0054] There are no particular limitations on the method for producing resin molded products using the PAT resin composition of this embodiment, and known methods can be employed. For example, the PAT resin composition of this embodiment can be put into an extruder, melt-kneaded to form pellets, and then these pellets can be put into an injection molding machine equipped with a predetermined mold and injected to produce the product.

[0055] The resin molded articles of this embodiment can be suitably used as resin compositions for molded articles that are exposed to high temperature and high humidity environments for long periods of time, such as in automobiles, trains, and the aerospace industry. Molded articles made from this resin composition can be used in connectors and the like because degradation due to hydrolysis can be prevented even when used for long periods of time in sufficiently high temperature and high humidity environments. [Examples]

[0056] The embodiment will be described in more detail below with reference to examples, but this embodiment is not limited to the following examples.

[0057] [Examples 1-6, Comparative Examples 1-10] In each example, comparative example, and reference example, components (A) to (F) were used in the ratios (parts by mass) shown in Tables 2 and 3. A 30 mmφ twin-screw extruder (manufactured by Japan Steel Works Ltd., TEX30C) was used, with the raw material supply section and die tip cylinder temperature set to 260°C, and the temperature between them set to 220-260°C. The mixture was melt-kneaded and extruded at a discharge rate of 15 kg / h and a screw rotation speed of 130 rpm to obtain pellets made of PBT resin composition. Details of each component shown in Tables 2 and 3 are shown below. (1) PAT resin (A); • PBT resin (A1): Manufactured by Polyplastics Co., Ltd., polybutylene terephthalate resin, Duranex PBT 300FP • PBT resin (A2): Manufactured by Polyplastics Co., Ltd., polybutylene terephthalate resin, Duranex PBT 500FP (2) Carbodiimide compound (B): Stabaxol P-100, aromatic polycarbodiimide, manufactured by Lanxess. (3) Inorganic filler (C); • Glass fiber (C1): E-glass glass fiber, average fiber diameter 13 μm (surface treatment agent: 0.5% by mass of phenol novolac resin, 0.2% by mass of copolymer of maleic anhydride, methyl methacrylate, and methyl acrylate) • Glass fiber (C2): E-glass glass fiber, average fiber diameter 13 μm (surface treatment agent: 0.5% by mass of phenol novolac resin, 0.2% by mass of polymerized methacrylic acid) • Glass fiber (C3): E-glass glass fiber, average fiber diameter 13 μm (surface treatment agent: phenol novolac resin 0.5% by mass) • Glass fiber (C4): E-glass glass fiber, average fiber diameter 13 μm (surface treatment agent: copolymer of maleic anhydride, methyl methacrylate, and methyl acrylate 0.2% by mass) • Glass fiber (C5): E-glass glass fiber, average fiber diameter 13 μm (surface treatment agent: 0.55 mass% phenol novolac resin, 0.46 mass% copolymer of maleic anhydride, methyl methacrylate, and methyl acrylate) • Glass fiber (C6): E-glass glass fiber, average fiber diameter 13 μm (surface treatment agent: phenol novolac resin 1.5% by mass, copolymer of maleic anhydride, methyl methacrylate and methyl acrylate 0.6% by mass) (4) Antioxidant (D): Irganox 1010 manufactured by BASF Japan (5) Lubricant (E): Rikemar B-74, manufactured by Riken Vitamin Co., Ltd. (6) Epoxy compound (F): Epicoat 1004, manufactured by Mitsubishi Chemical Corporation

[0058] Table 1 shows the components of the sizing agent used for surface treatment of glass fibers (C1) to (C6). The values ​​in Table 1 represent the content (mass %) of each component relative to the total amount of glass fiber. For glass fibers (C1) and (C2), the sizing agent is contained in an amount of 0.7 parts by mass per 100 parts by mass of glass fibers (C1) and (C2). Similarly, for glass fibers (C5) and (C6), the sizing agent is contained in an amount of 1.02 parts by mass and 2.15 parts by mass, respectively, per 100 parts by mass of glass fibers (C5) and (C6).

[0059] [Table 1]

[0060] [evaluation] The pellets obtained in each example, comparative example, and reference example were used to conduct the following evaluation tests. 《Hydrolysis resistance》 Pellets prepared with the compositions shown in Tables 2 and 3 were dried at 140°C for 3 hours, and then injection molded at a cylinder temperature of 260°C and a mold temperature of 80°C to produce 1A-type tensile test specimens in accordance with ISO 3167. The tensile strength of the obtained specimens was measured in accordance with ISO 527-1 and 527-2. The measurement results are shown in Tables 2 and 3. Next, using a PCT treatment apparatus (high-accelerated life testing apparatus), the specimens were exposed to 121°C and 100% RH, and the tensile strength was measured after the moist heat test (after 50 hours, 100 hours, and 150 hours) to calculate the strength retention rate before and after moist heat treatment. The calculation results are shown in Tables 2 and 3.

[0061] [Table 2]

[0062] [Table 3]

[0063] Tables 2 and 3 show that in Examples 1 to 6, good evaluation results were obtained regarding hydrolysis resistance. On the other hand, Comparative Example 8, which differed from Example 3 only in that it did not use carbodiimide compound (B), exhibited inferior hydrolysis resistance. Furthermore, Comparative Example 4, which differed from Example 3 only in that it used glass fibers (C3) surface-treated with a sizing agent containing only phenol novolac resin, exhibited inferior hydrolysis resistance. Furthermore, Comparative Example 7, which differed from Example 3 only in that it used glass fibers (C4) surface-treated with a sizing agent containing only a copolymer of maleic anhydride, methyl methacrylate, and methyl acrylate, exhibited inferior hydrolysis resistance. Furthermore, Comparative Example 9, which had an insufficient content of carbodiimide compound (B), exhibited poor hydrolysis resistance. Furthermore, Comparative Example 10, which had epoxy compound (F) added to the composition of Comparative Example 8, also exhibited inferior hydrolysis resistance.

Claims

1. Polyalkylene terephthalate resin (A), Carbodiimide compound (B), and The inorganic filler (C) is surface-treated with a sizing agent containing a polymer containing constituent units derived from carboxylic acids and / or carboxylic acid anhydrides and an epoxy resin, The polymer containing the constituent units derived from the carboxylic acid and / or carboxylic acid anhydride includes a copolymer of maleic anhydride, methyl methacrylate and methyl acrylate, A polyalkylene terephthalate resin composition containing 0.4 to 10 parts by mass of the carbodiimide compound (B) per 100 parts by mass of the polyalkylene terephthalate resin (A).

2. The polyalkylene terephthalate resin composition according to claim 1, wherein the carbodiimide compound (B) is an aromatic carbodiimide.

3. The polyalkylene terephthalate resin composition according to claim 1 or 2, wherein the inorganic filler (C) is fibrous, has an average fiber diameter of 3 to 50 μm, and contains 0.4 to 3.0 parts by mass of the sizing agent per 100 parts by mass of the inorganic filler (C).

4. A resin molded article obtained by molding the polyalkylene terephthalate resin composition according to claim 1 or 2.

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