Thermoplastic polyester resin composition and molded article comprising the same

Abstract

To provide a thermoplastic polyester resin composition excellent in hydrolysis resistance, and a molded article comprising the same.SOLUTION: (B) 20 to 100 parts by weight of glass fibers having an epoxy concentration of 0.08 to 2.5 00meq / g, and (C) 0.5 to 5.0 parts by weight of dicyclopentadiene type epoxy resins.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a thermoplastic polyester resin having excellent hydrolysis resistance, which is useful for applications such as electrical and electronic equipment parts, automobile parts, and machine parts, and to a molded article made of the same. [Background technology]

[0002] Thermoplastic polyester resins are used in a wide range of fields, including mechanical components, electrical and electronic components, and automotive parts, taking advantage of their excellent injection moldability and mechanical properties.

[0003] However, thermoplastic polyester resins are susceptible to degradation due to hydrolysis, and therefore, in order to be used as industrial materials for machinery parts, electrical and electronic parts, automotive parts, and the like, they are required to have long-term hydrolysis resistance in addition to a balance of general chemical and physical properties.

[0004] In addition, in recent years, there has been a growing demand for the recycling of polyester resins in preparation for a decarbonized society. There is also a need to reduce waste by recovering recycled polyester resins from non-standard products in the production process or from products that have been discarded after being used as specified products and reproducing them into polyester resin products.

[0005] To date, known methods for imparting hydrolysis resistance to thermoplastic polyester resins include blending an epoxy resin with a thermoplastic polyester resin and blending a hindered amine compound with the thermoplastic polyester resin. Examples of such resin compositions include a polyester resin composition (Patent Document 1) obtained by blending a dicyclopentadiene-type novolac epoxy resin and a specific hindered amine compound with a polybutylene terephthalate resin, a polyester resin composition (Patent Document 2) obtained by blending a carbodiimide compound and an inorganic filler having a plate-like cross section with a polybutylene terephthalate resin, and a polyester resin (Patent Document 3) obtained by blending polyethylene terephthalate and a reinforcing filler with a PBT resin having a terminal carboxyl group content of 30 eq / t or less and a temperature-decreasing crystallization temperature of 175°C or higher, or a temperature-decreasing crystallization temperature of 175°C or higher and a residual tetrahydrofuran content of 300 ppm or less. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2019-147934 [Patent Document 2] Japanese Patent Application Publication No. 2019-26842 [Patent Document 3] Japanese Patent Application Laid-Open No. 2004-143209 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in Patent Document 1, a large amount of gas is generated during molding due to the inclusion of a low-molecular-weight hindered amine compound, while in Patent Document 2, there is a problem in that it is difficult to achieve high hydrolysis resistance when a carbodiimide compound is blended.

[0008] Furthermore, Patent Document 3 specifies the amount of terminal carboxyl groups in polybutylene terephthalate resins. However, the recycled polyester resins have a high carboxyl group concentration due to the thermal history in the recycling process, and therefore, when such recycled polyester resins are used, there is a problem that they do not have good hydrolysis resistance.

[0009] An object of the present invention is to provide a thermoplastic polyester resin having excellent hydrolysis resistance and useful for applications such as electrical and electronic equipment parts, automobile parts, and machine parts, as well as molded articles made therefrom. Another object of the present invention is to provide a thermoplastic polyester resin composition having high quality even when recycled polyester resin is used, and a molded article made therefrom. [Means for solving the problem]

[0010] As a result of extensive investigations into solving the above-mentioned problems, the present inventors discovered that the above-mentioned problems can be solved by blending specific amounts of (A) a thermoplastic polyester resin, (B) glass fiber having an epoxy concentration of 0.08 to 2.00 meq / g, and (C) a dicyclopentadiene-type epoxy resin, and arrived at the present invention. That is, the present invention has the following configuration. 1. A thermoplastic polyester resin composition obtained by blending 100 parts by weight of (A) thermoplastic polyester resin with 20 to 100 parts by weight of (B) glass fiber having an epoxy concentration of 0.08 to 2.00 meq / g and 0.5 to 5.0 parts by weight of (C) dicyclopentadiene-type epoxy resin. 2. The thermoplastic polyester resin composition described in item 1, characterized in that the (A) thermoplastic polyester resin comprises at least one selected from (A-1) polybutylene terephthalate resin and (A-2) polyethylene terephthalate resin. 3. The thermoplastic polyester resin composition according to item 2, wherein the (A-2) polyethylene terephthalate resin comprises at least one selected from post-industrial materials and post-consumer materials. 4. A thermoplastic polyester resin composition according to any one of items 2 and 3, characterized in that 100 parts by weight of the (A) thermoplastic polyester resin is a blend of 30 to 70 parts by weight of (A-1) polybutylene terephthalate resin and 30 to 70 parts by weight of (A-2) polyethylene terephthalate resin. 5. The thermoplastic polyester resin composition according to any one of items 1 to 4, further comprising 0.01 to 1.0 parts by weight of (D) aliphatic alkyl acid phosphate blended with 100 parts by weight of (A) the thermoplastic polyester resin. 6. The thermoplastic polyester resin composition according to any one of items 2 to 4, wherein the (A-1) polybutylene terephthalate resin has a melt flow rate (MFR) measured at 250°C and 1000 gf of 1 to 50 g / 10 min. 7. A molded article made of the thermoplastic polyester resin according to any one of items 1 to 6. [Effects of the Invention]

[0011] According to the thermoplastic polyester resin composition of the present invention, a molded article having excellent hydrolysis resistance can be obtained. DETAILED DESCRIPTION OF THE INVENTION

[0012] Next, the thermoplastic polyester resin composition of the present invention will be described in detail.

[0013] The thermoplastic polyester resin composition of the present invention is prepared by blending (A) 100 parts by weight of a thermoplastic polyester resin with (B) 20 to 100 parts by weight of glass fibers having an epoxy concentration of 0.08 to 2.00 meq / g and (C) 0.5 to 5.0 parts by weight of a dicyclopentadiene-type epoxy resin.

[0014] Although thermoplastic polyester resins are excellent in injection molding and mechanical properties, their ester bonds are easily decomposed by hydrolysis, resulting in an increase in the concentration of carboxyl end groups. As the concentration of carboxyl end groups increases, the molecular weight of the thermoplastic polyester resin decreases, the mechanical properties deteriorate, and during molding processing, the viscosity decreases, resulting in defects such as flash in the molded product.

[0015] In the present invention, by blending (A) thermoplastic polyester resin with (B) glass fiber having an epoxy concentration of 0.08 to 2.00 meq / g (hereinafter sometimes abbreviated as (B) glass fiber) and (C) dicyclopentadiene-type epoxy resin, the carboxyl terminal groups of the (A) thermoplastic polyester resin generated by hydrolysis react with the epoxy groups of the (B) glass fiber having an epoxy concentration of 0.08 to 2.00 meq / g and the epoxy groups of the (C) dicyclopentadiene-type epoxy resin, thereby suppressing an increase in the carboxyl terminal groups.

[0016] Furthermore, during melt-kneading to obtain the thermoplastic polyester resin composition of the present invention, reactions between the carboxyl terminal groups of the (A) thermoplastic polyester resin and the epoxy groups of the (B) glass fiber, and between the carboxyl terminal groups of the (A) thermoplastic polyester resin and the epoxy groups of the (C) dicyclopentadiene-type epoxy resin, proceed, resulting in a decrease in the initial carboxyl terminal group concentration of the obtained thermoplastic polyester resin composition. As a result, the thermoplastic polyester resin composition of the present invention can maintain the high mechanical properties of the (A) thermoplastic polyester resin.

[0017] In the present invention, by using glass fibers (B) having an epoxy concentration of 0.08 to 2.00 meq / g, the reaction between carboxyl groups and epoxy groups occurs efficiently at the interface between the glass fibers (B) and the thermoplastic polyester resin (A), which more effectively suppresses an increase in the concentration of carboxyl terminal groups and improves hydrolysis resistance.

[0018] Here, the thermoplastic polyester resin composition of the present invention contains a reaction product obtained by reacting (A) a thermoplastic polyester resin with (B) glass fiber or (C) a dicyclopentadiene-type epoxy resin, but the reaction product is produced by a complex reaction, and there are circumstances in which it is impractical to identify its structure. Therefore, the present invention is defined by the components to be blended.

[0019] (A) Thermoplastic polyester resin 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) a dicarboxylic acid or its ester-forming derivative and a diol or its ester-forming derivative, (2) a hydroxycarboxylic acid or its ester-forming derivative, and (3) a lactone. Here, "having as its main structural unit" refers to the presence of 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 the presence of 80 mol % or more of these residues. Among these, polymers or copolymers having, as their main structural units, (1) residues of a dicarboxylic acid or its ester-forming derivative and a diol or its ester-forming derivative are preferred due to their superior injection moldability and mechanical properties.

[0020] 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.

[0021] 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.

[0022] 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 suitable aromatic polyester resins include polypropylene 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. These polymers and copolymers may be used alone or in combination of two or more. Here, " / " indicates copolymer.

[0023] Among these, from the viewpoints of injection moldability and mechanical properties, polymers or copolymers having, as main structural units, residues of aromatic dicarboxylic acids or their ester-forming derivatives and residues of aliphatic diols or their ester-forming derivatives are more preferred, and polymers or copolymers having, as main structural units, residues of terephthalic acid, naphthalenedicarboxylic acid or their ester-forming derivatives and residues of aliphatic diols or their ester-forming derivatives selected from ethylene glycol, propylene glycol, and 1,4-butanediol are even more preferred.

[0024] Among these, at least one aromatic polyester resin selected from polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polypropylene naphthalate, polybutylene naphthalate, polypropylene isophthalate / terephthalate, polybutylene isophthalate / terephthalate, polypropylene terephthalate / naphthalate, polybutylene adipate / terephthalate, polybutylene terephthalate / sebacate, and polybutylene terephthalate / naphthalate is particularly preferred, and at least one selected from polyethylene terephthalate, polybutylene terephthalate, polybutylene isophthalate / terephthalate, polybutylene decanedicarboxylate / terephthalate, polybutylene terephthalate / naphthalate, and polybutylene / ethylene terephthalate is more preferred.

[0025] From the viewpoint of mechanical properties, the (A) thermoplastic polyester resin used in the present invention more preferably contains at least one selected from (A-1) polybutylene terephthalate resin and (A-2) polyethylene terephthalate resin. To improve hydrolysis resistance, it is more preferable that 100 parts by weight of the (A) thermoplastic polyester resin be blended with 30 to 70 parts by weight of the (A-1) polybutylene terephthalate resin and 70 to 30 parts by weight of the (A-2) polyethylene terephthalate resin. It is even more preferable that the (A-1) polybutylene terephthalate resin be blended with 40 to 60 parts by weight of the (A-1) polybutylene terephthalate resin and 60 to 40 parts by weight of the (A-2) polyethylene terephthalate resin. The (A-1) polybutylene terephthalate resin used in the present invention is a polymer obtained by a polymerization method such as polycondensation reaction of terephthalic acid or its ester-forming derivative and 1,4-butanediol or its ester-forming derivative as the main components. The term "major components" as used herein refers to 50 mol% or more of the dicarboxylic acid component and diol component, respectively, consisting of terephthalic acid or its ester-forming derivative and 1,4-butanediol or its ester-forming derivative. Other copolymer components may also be included within the range that does not impair the properties, for example, within a range of approximately 20 mol% or less of the raw material. Preferred examples of these polymers and copolymers include polybutylene terephthalate, polybutylene (terephthalate / isophthalate), polybutylene (terephthalate / adipate), polybutylene (terephthalate / sebacate), polybutylene (terephthalate / decanedicarboxylate), polybutylene (terephthalate / naphthalate), and poly(butylene / ethylene) terephthalate. These may be used alone or in combination.

[0026] The polybutylene terephthalate resin (A-1) used in the present invention preferably has a melt flow rate (MFR) of 1 to 50 g / 10 min when measured at 250°C and 1000 gf from the viewpoint of fluidity, and more preferably 25 to 45 g / 10 min from the viewpoint of injection moldability.

[0027] The method for producing the polybutylene terephthalate resin (A-1) used in the present invention is not particularly limited, and known polycondensation methods, ring-opening polymerization methods, etc. can be used. Either batch polymerization or continuous polymerization methods are acceptable, and methods involving transesterification and polycondensation reactions, as well as methods involving direct polymerization polycondensation reactions (direct polymerization methods), can also be applied. Direct polymerization methods are preferred because they facilitate control of the amount of carboxyl end groups and are economical. It is preferable to add a catalyst during these reactions to effectively promote the esterification reaction or transesterification and polycondensation reactions. Specific examples of the 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 of titanic acid, or mixed esters thereof, dibutyltin oxide, methylphenyltin oxide, tetraethyltin, hexaethylditin oxide, cyclohexahexylditin oxide, didodecyltin oxide, and triethyltin hydroxide. Examples of suitable polymerization catalysts include tin compounds such as tin hydroxide, triphenyltin hydroxide, triisobutyltin acetate, dibutyltin diacetate, diphenyltin dilaurate, monobutyltin trichloride, dibutyltin dichloride, tributyltin chloride, dibutyltin sulfide, butylhydroxytin oxide, and 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 catalysts can also be used in combination. From the viewpoint of the carboxyl group concentration of the (A-1) polybutylene terephthalate resin, organic titanium compounds and tin compounds are preferred, with tetra-n-butyl ester of titanic acid being even more preferred. The amount of polymerization catalyst used is preferably 0.01 to 0.2 parts by weight per 100 parts by weight of the (A-1) polybutylene terephthalate resin.

[0028] The polyethylene terephthalate resin (A-2) used in the present invention is a polymer obtained by a polymerization reaction such as polycondensation of terephthalic acid or its ester-forming derivative and ethylene glycol or its ester-forming derivative as the main components. The term "main component" here refers to a dicarboxylic acid component and a diol component each consisting of terephthalic acid or its ester-forming derivative and ethylene glycol or its ester-forming derivative, respectively. Other copolymerization components may be included within a range that does not impair the properties, for example, within a range of about 20 mol% or less of the raw materials. The term "main component" here refers to a dicarboxylic acid component and a diol component each independently accounting for more than 50 parts by weight of each component. Preferred examples of these polymers and copolymers include polyethylene terephthalate, polyethylene (terephthalate / isophthalate), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sebacate), polyethylene (terephthalate / decanedicarboxylate), and polyethylene (terephthalate / naphthalate), and these may be used alone or in combination of two or more.

[0029] The polyethylene terephthalate resin (A-2) used in the present invention preferably has a melt flow rate (MFR) of 1 to 50 g / 10 min when measured at 275°C and 350 gf from the viewpoint of fluidity, and more preferably 10 to 45 g / 10 min from the viewpoint of injection moldability.

[0030] The method for producing the polyethylene terephthalate resin (A-2) used in the present invention is not particularly limited, and known polycondensation methods, ring-opening polymerization methods, etc. can be used. Either batch polymerization or continuous polymerization methods are acceptable, and methods involving transesterification and polycondensation reactions, as well as methods involving direct polymerization polycondensation reactions (direct polymerization methods), can also be applied. Direct polymerization methods are preferred because they facilitate control of the amount of carboxyl end groups and are economical. It is preferable to add a catalyst during these reactions to effectively promote the esterification reaction or transesterification and polycondensation reactions. Specific examples of the 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 of titanic acid, or mixed esters thereof, dibutyltin oxide, methylphenyltin oxide, tetraethyltin, hexaethylditin oxide, cyclohexahexylditin oxide, didodecyltin oxide, and triethyltin hydroxide. Examples of suitable polymerization catalysts include tin compounds such as tin hydroxide, triphenyltin hydroxide, triisobutyltin acetate, dibutyltin diacetate, diphenyltin dilaurate, monobutyltin trichloride, dibutyltin dichloride, tributyltin chloride, dibutyltin sulfide, butylhydroxytin oxide, and 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 catalysts can also be used in combination. From the viewpoint of the carboxyl group concentration of the (A-2) polyethylene terephthalate resin, organic titanium compounds and tin compounds are preferred, with tetra-n-butyl ester of titanic acid being even more preferred. The amount of polymerization catalyst used is preferably 0.01 to 0.2 parts by weight per 100 parts by weight of the (A-2) polyethylene terephthalate resin.

[0031] The polyethylene terephthalate resin (A-2) in the present invention may be a virgin polyethylene terephthalate resin obtained by polymerization reaction of raw material monomers, or may be a post-industrial material obtained from non-standard products in the manufacturing process, or a post-consumer material obtained by recovering resin products using polyethylene terephthalate resin distributed on the market. Either one of these or both may be mixed and used in any ratio.

[0032] The polyethylene terephthalate resin, which is a post-industrial or post-consumer material referred to in the present invention, is derived from, for example, non-standard pellets generated during the production of polyethylene terephthalate resin, non-standard products generated during the production of resin products such as bottles, films, fibers, and injection-molded products, post-industrial products such as sprues, runners, and pellet waste generated during molding, and post-consumer products obtained by recovering products containing polyethylene terephthalate resin from the market. Examples of polyethylene terephthalate resin, which is a post-industrial or post-consumer material, include chemically recycled products obtained by depolymerizing a resin product containing polyethylene terephthalate resin recovered from the market, decomposing the polyethylene terephthalate resin, and then repolymerizing the decomposed polyethylene terephthalate resin; flake-shaped recycled products obtained by crushing the recovered polyethylene terephthalate resin; and material recycled products such as pellet-shaped recycled products obtained by cutting the molten resin discharged from a die after heat-melting during the production of a resin composition containing polyethylene terephthalate resin.

[0033] It is preferable to use a post-industrial material or a post-consumer material as the polyethylene terephthalate resin (A-2) in the present invention, since this allows for reductions in waste and carbon dioxide emissions.

[0034] The polyethylene terephthalate resin (A-2) used in the present invention as a post-industrial or post-consumer material may contain components other than polyethylene terephthalate resin as long as the components do not affect the properties of the polyester resin of the present invention. Examples of components other than polyethylene terephthalate resin include stabilizers, weathering agents, lubricants, pigments, dyes, crystal nucleating agents, plasticizers, antistatic agents, flame retardants, color inhibitors, inorganic fillers such as fibrous reinforcing materials, and polymers other than polyethylene terephthalate resin.

[0035] (B) Glass fiber with an epoxy concentration of 0.08 to 2.00 meq / g The glass fiber (B) used in the present invention must be surface-treated with a surface treatment agent such as a sizing agent to improve hydrolysis resistance and interfacial adhesion with the polybutylene terephthalate resin, and the epoxy concentration contained in the glass fiber must be 0.08 to 2.00 meq / g. If the epoxy concentration is less than 0.08 meq / g, hydrolysis resistance will be insufficient. If the epoxy concentration is more than 2.00 meq / g, it will be difficult to maintain fluidity.

[0036] The method for measuring the epoxy concentration contained in glass fiber complies with JIS K7236:2001, and (B) the surface treatment agent is extracted from 1 g of glass fiber with chloroform, and acetic acid, triethylammonium bromide / acetic acid solution, and crystal violet / acetic acid solution are added as indicators, and the epoxy group concentration is calculated by titrating with 0.1 mol / L perchloric acid / acetic acid.

[0037] The surface treatment agent for (B) glass fiber used in the present invention is preferably a sizing agent containing one or more epoxy compounds such as bisphenol-type epoxy, novolac-type epoxy, epoxysilane compound, etc. Other surface treatment agents for (B) glass fiber may also be used, such as silane coupling agents such as aminosilane compounds, urethane, copolymers made of acrylic acid such as acrylic acid / styrene copolymers, copolymers made of maleic anhydride such as methyl acrylate / methyl methacrylate / maleic anhydride copolymers, and sizing agents containing vinyl acetate.

[0038] The (B) glass fiber used in the present invention may be a chopped strand type or a roving type, and is available, for example, under the trade name T-158H from Nippon Electric Glass Co., Ltd. The (B) glass fiber preferably has an average fiber diameter of 4 to 25 μm, more preferably 6 to 20 μm. From the viewpoint of mechanical strength, it is more preferably 20 μm or less, and from the viewpoint of dispersibility of the glass fiber, it is preferably 6 μm or more.

[0039] (C) Dicyclopentadiene epoxy resin The dicyclopentadiene epoxy resin (C) used in the present invention is represented by the following general formula (1) and contains an epoxy group in the molecule.

[0040] [ka] In the general formula (1), n ​​represents the number of repeating units of the dicyclopentadiene epoxy resin (C). The number of repeating units, n, of the dicyclopentadiene epoxy resin (C) used in the present invention is preferably in the range of 0 to 10. If the number of repeating units, n, is large, the reaction between the dicyclopentadiene epoxy resins (C) is more likely to proceed, leading to the formation of a crosslinked structure, and the retention stability of the thermoplastic polyester resin composition is deteriorated. From the viewpoint of retention stability, the number of repeating units, n, of the dicyclopentadiene epoxy resin is more preferably 0 to 4, and even more preferably 1 to 3.

[0041] The dicyclopentadiene-type epoxy resin (C) used in the present invention must be blended in an amount of 0.5 to 5.0 parts by weight per 100 parts by weight of the thermoplastic polyester resin (A). If the amount is less than 0.5 parts by weight, hydrolysis resistance will be insufficient. If the amount exceeds 5.0 parts by weight, viscosity will increase during molten retention. From the viewpoint of moldability, the amount is more preferably 1.0 to 3.5 parts by weight, and even more preferably 1.0 to 3.0 parts by weight. Commercially available dicyclopentadiene-type epoxy resins include "Epiclon" (registered trademark) HP-7200H (manufactured by DIC Corporation) and XD-1000 (manufactured by Nippon Kayaku Co., Ltd.).

[0042] (D) Aliphatic alkyl acid phosphate The aliphatic alkyl acid phosphate used in the present invention has the effect of suppressing the elimination of the aliphatic alcohol moiety contained in the (A) thermoplastic polyester resin due to ester exchange, and improving stability during molten retention.

[0043] In the thermoplastic polyester resin composition of the present invention, the blending amount of (D) aliphatic alkyl acid phosphate is preferably 0.01 to 1.0 part by weight per 100 parts by weight of (A) thermoplastic polyester resin. By blending an amount of 0.01 part by weight or more, sufficient melt residence stability can be obtained. More preferably, it is 0.03 part by weight or more. By blending an amount of 1.0 part by weight or less, good mechanical properties can be obtained. More preferably, it is 0.8 part by weight or less.

[0044] Examples of the (D) aliphatic alkyl acid phosphate used in the present invention include methyl acid phosphate, ethyl acid phosphate, propyl acid phosphate, butyl acid phosphate, lauryl acid phosphate, stearyl acid phosphate, decyl acid phosphate, dodecyl acid phosphate, and octadecyl acid phosphate. A mixture containing one or more of these may also be used. Octadecyl acid phosphate is a particularly preferred aliphatic alkyl acid phosphate. The use of (D) aliphatic alkyl acid phosphate can suppress an increase in viscosity during melting during injection molding.

[0045] [Other ingredients] The thermoplastic polyester resin composition of the present invention may contain other resin components, flame retardants, fillers other than (B) glass fiber, stabilizers, crystal nucleating agents, colorants, lubricants, and other conventional additives, and two or more of these may be contained in the composition, as long as the effects of the present invention are not impaired.

[0046] The other resin components may be any melt-moldable resin, and examples thereof include AS resin (acrylonitrile / styrene copolymer), hydrogenated or unhydrogenated SBS resin (styrene / butadiene / styrene triblock copolymer), hydrogenated or unhydrogenated SIS resin (styrene / isoprene / styrene triblock copolymer), polyethylene resin, polypropylene resin, polymethylpentene resin, cyclic olefin resin, cellulose resin such as cellulose acetate, polycarbonate resin, polytrimethylene terephthalate resin, polyamide resin, polyacetal resin, polysulfone resin, polyphenylene sulfide resin, polyether ether ketone resin, polyimide resin, and polyetherimide resin.

[0047] In particular, amorphous resins such as AS resin (acrylonitrile / styrene copolymer) can be easily melt-kneaded with thermoplastic polyester resins, and by blending them together, molded products with excellent dimensional stability can be produced.

[0048] (B) Fillers other than glass fiber can be used in any form, including fibrous, plate-like, powdery, and granular fillers. Examples of fibrous fillers include carbon fiber, metal fiber, and organic fibers (such as nylon, polyester, aramid, polyphenylene sulfide, liquid crystal polymer, and acrylic). These can be used alone or in combination. Examples of plate-like, powdery, and granular fillers include whisker-like fillers such as rock wool, potassium titanate whiskers, barium titanate whiskers, aluminum borate whiskers, and silicon nitride whiskers; and powdery, granular, or plate-like fillers such as mica, talc, kaolin, silica, calcium carbonate, glass beads, glass flakes, glass microballoons, clay, molybdenum disulfide, wollastonite, montmorillonite, titanium oxide, zinc oxide, calcium polyphosphate, graphite, and barium sulfate. These fillers can be used alone or in combination.

[0049] As the flame retardant, any of those used as flame retardants for polyester resin compositions can be used. For example, organic halogen-based flame retardants, specifically high molecular weight organic halogen compounds such as halogenated polycarbonates (e.g., carbonate oligomers of tetrabromobisphenol A), halogenated acrylic resins, halogenated epoxy resins, halogenated phenoxy resins, halogenated polystyrenes, tetrabromobisphenol A·ethyl ether oligomers, and halogenated polyphenylene ethers (e.g., polydibromophenylene oxide); decabromodiphenyl ether, hexabromophenol, and tetrabromobisphenol A·bis(2,3-dibromopropyl ether); Examples of suitable flame retardants include low-molecular-weight organic halogen compounds such as brominated bisphenol A (e.g., tetrabromobisphenol A bis(allyl ether), tetrabromobisphenol A 2-hydroxyethyl ether), hexabromobenzene, tetrabromophthalic anhydride, tribromophenol, bis(tribromophenoxy)ethane, bis(pentabromophenoxy)ethane, ethylene bistetrabromophthalimide, brominated styrene, tetrabromobisphenol S, and bis(2,3-dibromopropyl ether) of tetrabromobisphenol S. These organic halogen flame retardants may be used alone or in combination. Phosphorus-based (other than (D) aliphatic alkyl acid phosphates) and inorganic flame retardants may also be used.

[0050] As the stabilizer, any of those used as stabilizers for polyester resin compositions can be used. Examples include antioxidants, light stabilizers, catalyst deactivators, etc. Two or more of these may be blended.

[0051] The nucleating agent may be either an inorganic nucleating agent or an organic nucleating agent, and these may be used alone or in combination of two or more. In the thermoplastic polyester resin composition of the present invention, the amount of the nucleating agent is preferably 0.01 to 5.0 parts by weight per 100 parts by weight of the thermoplastic polyester resin (A). When the amount is 0.01 part by weight or more, excellent moldability is obtained, and when the amount is 5.0 parts by weight or less, good mechanical properties are obtained. A more preferred amount is 0.05 to 4.0 parts by weight.

[0052] Examples of colorants include organic dyes, organic pigments, inorganic pigments, etc. Two or more of these may be blended together.

[0053] Examples of lubricants include, but are not limited to, metal soaps such as calcium stearate and barium stearate, fatty acid esters, salts of fatty acid esters (including partial salts), fatty acid amides such as ethylene bisstearamide, polycondensates of ethylenediamine, stearic acid, and sebacic acid, or fatty acid amides formed from polycondensates of phenylenediamine, stearic acid, and sebacic acid, polyalkylene waxes, acid anhydride-modified polyalkylene waxes, and mixtures of the above lubricants with fluorine-based resins or fluorine-based compounds. In the thermoplastic polyester resin composition of the present invention, the amount of lubricant is preferably 0.05 to 1.5 parts by weight per 100 parts by weight of the thermoplastic polyester resin (A). If the amount is less than 0.05 parts by weight, mold releasability decreases. If the amount is more than 1.5 parts by weight, gas generation and mold fouling during molding become significant. From the viewpoint of moldability, the amount is more preferably 0.1 to 1.0 parts by weight.

[0054] The thermoplastic polyester resin composition of the present invention preferably has the above-mentioned components (A) to (D) and, if necessary, other components uniformly dispersed therein. Examples of methods for producing the thermoplastic polyester resin composition of the present invention include a method in which the components are melt-kneaded using a known melt-kneader such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, or a mixing roll. The components may be mixed together in advance and then melt-kneaded. The moisture content of each component is preferably low, and it is desirable to dry the components in advance, if necessary.

[0055] In addition, examples of methods for feeding each component into a melt kneader include a method in which (A), (C), and, if necessary, (D) and other components are fed into a main feeding port installed at the base of the screw using a single-screw or twin-screw extruder, and (B) is fed into a sub-feeding port installed between the main feeding port and the tip of the extruder, and the components are melt-mixed.

[0056] The melt-kneading temperature is preferably 190 to 340°C, more preferably 210 to 310°C, and even more preferably 240 to 290°C, in terms of excellent fluidity and mechanical properties.

[0057] The resin composition of the present invention can be molded by any conventional method such as injection molding, extrusion molding, blow molding, press molding, spinning, etc., and can be processed into various molded articles for use. The molded articles can be used as injection molded articles, extrusion molded articles, blow molded articles, films, sheets, fibers, etc. The films can be used as various films such as unstretched, uniaxially stretched, and biaxially stretched films, and the fibers can be used as various fibers such as unstretched yarns, stretched yarns, and ultrastretched yarns.

[0058] In the present invention, the various molded articles described above can be used for a variety of purposes, such as automobile parts, electrical and electronic parts, building materials, various containers, daily necessities, household goods, and sanitary products. In particular, the thermoplastic polyester resin composition of the present invention has excellent retention stability when heated and melted, allowing for the production of good, small, thin-walled molded articles, making it particularly suitable for use as connector parts for electrical and electronic equipment components. Furthermore, because the thermoplastic polyester resin composition of the present invention has excellent hydrolysis resistance and retention stability even after use as a molded article, molded articles for various purposes can be recycled and reused as various molded articles. [Example]

[0059] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The raw materials used in each example and comparative example are shown below.

[0060] (A) Thermoplastic polyester resin A-1-1: Polybutylene terephthalate (Toray Industries, Inc., "Trecon" (registered trademark), MFR: 35 g / 10 min (250°C, 1000 gf)). A-1-2: Polybutylene terephthalate (Toray Industries, Inc., "Trecon" (registered trademark), MFR: 57 g / 10 min (250°C, 1000 gf)). A-2-1: Post-industrial recycled polyethylene terephthalate (manufactured by Toray Industries, Inc., MFR: 13.5 g / 10 min (275°C, 375 gf)). A-2-2: Post-industrial recycled polyethylene terephthalate (manufactured by Toray Industries, Inc., MFR: 19.7 g / 10 min (275°C, 375 gf)). A-2-3: Post-consumer recycled polyethylene terephthalate (manufactured by Toray Industries, Inc., MFR: 35.8 g / 10 min (275°C, 375 gf)).

[0061] (B) Glass fiber with an epoxy concentration of 0.08 to 2.00 meq / g B-1: Chopped strand (T-158H (trade name) manufactured by Nippon Electric Glass Co., Ltd., 3 mm length, average fiber diameter: 10.5 μm, epoxy concentration: 0.09 meq / g).

[0062] (B') Glass fibers that do not fall under the category of glass fibers with an epoxy concentration of 0.08 to 2.00 meq / g B'-1: Chopped strands (T-187 (trade name) manufactured by Nippon Electric Glass Co., Ltd., 3 mm length, average fiber diameter: 13.0 μm, epoxy concentration: 0.07 meq / g).

[0063] (C) Dicyclopentadiene epoxy resin C-1: Dicyclopentadiene-type epoxy resin represented by general formula (1) having an epoxy equivalent of 290 g / eq (manufactured by DIC Corporation, "Epiclon" (registered trademark) HP-7200H).

[0064] (D) Aliphatic alkyl acid phosphate D-1: Octadecyl acid phosphate ("ADEKA STAB" (registered trademark) AX-71, manufactured by ADEKA Corporation).

[0065] (E) Lubricant E-1: Pentaerythritol tetrastearate ("Roxiol" (registered trademark) VPG861, manufactured by Emery Oleochemicals Japan Co., Ltd.).

[0066] (F) Crystal nucleus material F-1: Inorganic crystal nucleus material (Hitron (registered trademark) manufactured by Takehara Industrial Chemical Co., Ltd.).

[0067] The evaluation methods used in the examples and comparative examples are summarized below.

[0068] (1)(B) Glass fiber-derived epoxy group compounding concentration In accordance with JIS K7236:2001, (B) the surface treatment agent was extracted from 1 g of glass fiber with chloroform, and acetic acid, triethylammonium bromide / acetic acid solution, and crystal violet / acetic acid solution were added as indicators. The solution was titrated with 0.1 mol / L perchloric acid / acetic acid, and the epoxy group concentration was calculated using the following formula. Epoxy group concentration [eq / g] = (0.1 mol / L perchloric acid acetic acid [ml] required to titrate a solution of chloroform, from which the surface treatment agent for glass fiber (B) had been extracted, to which acetic acid and triethylammonium bromide / acetic acid solution had been added, and 0.1 mol / L perchloric acid acetic acid [ml] required to titrate a solution of chloroform to which acetic acid and triethylammonium bromide / acetic acid solution had been added) × concentration of 0.1 mol / L perchloric acid acetic acid [mol / ml] × 1 / amount of component (B) collected and used for titration [g]).

[0069] (2) Tensile properties The pellets obtained in each example and comparative example were dried for 3 hours in a hot air dryer at 130°C, and then multipurpose test specimens Type A (total length 150 mm, test section width 10 mm, thickness 4 mm) specified in ISO3167:2002 were prepared using an SE50DUZ injection molding machine manufactured by Sumitomo Heavy Industries, Ltd. under molding conditions of a cylinder temperature of 260°C and a mold temperature of 80°C. Using the obtained test specimens, tensile properties were measured in accordance with ISO527-1, -2:2012.

[0070] (3) Hydrolysis resistance The pellets obtained in each example and comparative example were used to mold test pieces in the same manner as in the method described in (2) above. These test pieces were subjected to hydrolysis treatment (PCT treatment) at 121°C and 100% RH for 50 or 100 hours using a HAST CHAMBER EHS-221M manufactured by TABAI ESPEC Co., Ltd. The tensile properties of the test pieces were measured in the same manner as in (2), and the tensile strength retention was calculated using the following formula to evaluate the hydrolysis resistance. Tensile strength retention rate (%) = (tensile strength (after hydrolysis treatment) (MPa) / tensile strength (before hydrolysis treatment) (MPa) × 100

[0071] [Table 1]

[0072] [Table 2]

[0073] [Examples 1 to 12, Comparative Examples 1 to 9] According to the formulations shown in Tables 1 and 2, (A) thermoplastic polyester resin, (C) dicyclopentadiene-type epoxy resin, and (D) aliphatic alkyl acid phosphate, as well as all other additives, were fed into the base of a twin-screw extruder. (B) Glass fiber was fed into a side inlet located between the main inlet and the tip of the extruder. The mixture was melt-kneaded in a twin-screw extruder (Toshiba Machine Co., Ltd., TEM37S (trade name)) with a screw diameter of 37 mm and a cylinder temperature set to 260°C. The strand extruded from the die was cooled in a cooling bath and then pelletized with a strand cutter to obtain a resin composition. The obtained resin composition was evaluated using the above-mentioned methods, and the results are shown in Tables 1 and 2.

[0074] The following is clear from Tables 1 and 2:

[0075] A comparison of Examples 1 to 12 and Comparative Examples 1 to 10 reveals that a thermoplastic polyester resin composition containing 100 parts by weight of (A) thermoplastic polyester resin, 20 to 100 parts by weight of (B) glass fiber with an epoxy concentration of 0.08 to 2.00 (meq / g), and 0.5 to 5.0 parts by weight of (C) dicyclopentadiene-type epoxy resin, exhibits excellent hydrolysis resistance. Furthermore, even when (A-2) polyethylene terephthalate resin, which is a post-industrial or post-consumer material, is used as the polyethylene terephthalate resin, it is possible to maintain hydrolysis resistance and exhibit excellent economic and environmental performance.

Claims

1. A thermoplastic polyester resin composition obtained by blending 20 to 100 parts by weight of (B) glass fibers having an epoxy concentration of 0.08 to 2.00 meq / g, and 0.5 to 5.0 parts by weight of (C) dicyclopentadiene-type epoxy resin with 100 parts by weight of (A) thermoplastic polyester resin.

2. 2. The thermoplastic polyester resin composition according to claim 1, wherein the thermoplastic polyester resin (A) comprises at least one selected from the group consisting of (A-1) polybutylene terephthalate resin and (A-2) polyethylene terephthalate resin.

3. 3. The thermoplastic polyester resin composition according to claim 2, wherein the polyethylene terephthalate resin (A-2) comprises at least one selected from post-industrial materials and post-consumer materials.

4. 3. The thermoplastic polyester resin composition according to claim 2, wherein 100 parts by weight of the thermoplastic polyester resin (A) is a blend of 30 to 70 parts by weight of the polybutylene terephthalate resin (A-1) and 70 to 30 parts by weight of the polyethylene terephthalate resin (A-2).

5. 3. The thermoplastic polyester resin composition according to claim 1, further comprising 0.01 to 1.0 parts by weight of (D) an aliphatic alkyl acid phosphate, based on 100 parts by weight of (A).

6. The thermoplastic polyester resin composition according to claim 2, characterized in that the (A-1) polybutylene terephthalate resin has a melt flow rate (MFR) measured at 250°C and 1000 gf of 1 to 50 g / 10 min.

7. A molded article made from the thermoplastic polyester resin composition according to claim 1 or 2.

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