Polyester resin composition and resin molded product

Abstract

To provide a recycled polyester resin composition with excellent flame retardancy and mold release properties. [Solution] A polyester resin composition comprising polybutylene terephthalate resin, recycled polyethylene terephthalate resin, a transesterification inhibitor, and a flame retardant, wherein the amount of terminal hydroxyl groups of the polybutylene terephthalate resin is 30 to 70 mmol / kg relative to the total amount of the polybutylene terephthalate resin and the recycled polyethylene terephthalate resin.

Description

[Technical Field]

[0001] Embodiments of the present invention relate to polyester resin compositions and resin molded articles. [Background technology]

[0002] In recent years, highly recyclable resins have been in demand for the realization of a sustainable society. Resins such as polyethylene, polystyrene, polypropylene, and polyethylene terephthalate, which are used in packaging and containers, have a high polymer ratio in packaging containers, so waste collected from the market is crushed, washed, and repelled to be used as recycled products. On the other hand, polybutylene terephthalate resin (hereinafter also called PBT resin) is often used with various additives such as inorganic fillers, impact modifiers, and flame retardants added according to market demands, so the polymer ratio of polybutylene terephthalate resin itself is low, making it difficult to obtain stable quality in the aforementioned processes. For this reason, methods such as recovering energy through thermal recycling or decomposing the polymer through chemical recycling and utilizing the recovered monomers by polymerization or as raw materials for other substances have been considered, but these methods consume a lot of energy and have not been widely adopted.

[0003] Therefore, studies are underway to increase the proportion of recycled plastics used in polybutylene terephthalate resin compositions by blending readily available recycled resins, such as recycled polyethylene terephthalate resin (hereinafter also referred to as recycled PET resin) and recycled polystyrene resin, with polybutylene terephthalate resin.

[0004] Blending polyethylene terephthalate resin (hereinafter also known as PET resin) or polystyrene resin with polybutylene terephthalate resin is commonly used for purposes such as improving dimensional accuracy, reducing warping, and improving appearance. However, since polystyrene resin reduces heat resistance, polyethylene terephthalate resin, which has a higher melting point, is used in automotive parts and electrical equipment such as induction cooktops where heat resistance is required. However, polyethylene terephthalate resin inhibits the crystallization of polybutylene terephthalate resin, which has resulted in problems with moldability.

[0005] Patent Document 1 describes a polyester resin composition containing polybutylene terephthalate resin, polyethylene terephthalate resin, an aluminum salt of diethylphosphinic acid, melamine cyanurate, and a phosphate ester, which exhibits an excellent balance of physical properties such as fluidity. Patent Document 2 describes a resin composition containing polybutylene terephthalate resin, polyethylene terephthalate resin, and a flame retardant, wherein the polyethylene terephthalate resin contains 1.0 to 100 μg / g of iron, and it is estimated that the iron contributes to improving the release properties of molded products obtained by molding the resin composition. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] International Publication No. 2024 / 043533 [Patent Document 2] Japanese Patent Publication No. 2023-81366 [Overview of the project] [Problems that the invention aims to solve]

[0007] Patent Document 1 does not contain any description regarding mold release properties, and Patent Document 2 showed that mold release properties were insufficient even when using polyethylene terephthalate resin containing iron elements. Embodiments of the present invention aim to provide a recycled polyester resin composition that exhibits excellent flame retardancy and mold release properties.

Means for Solving the Problems

[0008] One embodiment of the present invention relates to a polyester resin composition containing polybutylene terephthalate resin, recycled polyethylene terephthalate resin, an ester exchange inhibitor, and a flame retardant, wherein the amount of terminal hydroxyl groups of the polybutylene terephthalate resin is 30 to 70 mmol / kg with respect to the total amount of the polybutylene terephthalate resin and the recycled polyethylene terephthalate resin. Another embodiment of the present invention relates to a resin molded product obtained using the above-described polyester resin composition.

Advantages of the Invention

[0009] According to an embodiment of the present invention, a polyester resin composition excellent in flame retardancy and mold release property can be provided.

Brief Description of the Drawings

[0010] [Figure 1] It is a perspective view schematically showing a molded product used for evaluating the mold release property in an example.

Mode for Carrying Out the Invention

[0011] Preferred embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments.

[0012] <Polyester Resin Composition> The polyester resin composition of this embodiment is a polyester resin composition containing PBT resin, recycled PET resin, an ester exchange inhibitor, and a flame retardant, wherein the amount of terminal hydroxyl groups of the PBT resin is 30 to 70 mmol / kg with respect to the total amount of the PBT resin and the recycled PET resin.

[0013] In resin compositions containing PBT resin and PET resin, transesterification reactions tend to occur easily between the PBT resin and PET resin under high-temperature conditions such as during melting. If the transesterification reaction proceeds too far, the melting point and crystallization temperature of the resin composition change, and temperature characteristics such as the temperature of deflection under load, as well as tensile strength and elastic modulus, may decrease, resulting in a failure to obtain the expected physical properties. Furthermore, if the crystallization temperature changes and crystallization becomes difficult, shrinkage during injection molding may decrease, the solidification rate may decrease, rigidity may decrease, deformation may occur during mold release, and the molding cycle time may increase, leading to decreased productivity. The same applies when PET resin is replaced with recycled PET resin. Transesterification is a reaction in which the main chain is replaced by the reaction of ester groups and hydroxyl groups. Although it is affected by the concentration of hydroxyl groups, even if the total amount of hydroxyl groups in the resin composition is small, the release properties may not improve.

[0014] The polyester resin composition of this embodiment, which contains PBT resin, recycled PET resin, a transesterification inhibitor, and a flame retardant, and in which the amount of terminal hydroxyl groups of the PBT resin is 30 to 70 mmol / kg relative to the total amount of PBT resin and recycled PET resin, has excellent mold release properties and excellent flame retardancy.

[0015] [Polybutylene terephthalate resin] PBT resin contains at least terephthalic acid or its ester-forming derivative (C 1-6 The resin is obtained by polycondensation of a dicarboxylic acid component containing alkyl esters or acid halides (such as those of 1,4-butanediol) having at least 4 carbon atoms, or a glycol component containing an ester-forming derivative thereof (such as an acetylated compound). The PBT resin is not limited to homopolybutylene terephthalate resin, but may also be a copolymer containing 60 mol% or more (particularly 75 mol% to 95 mol%) of butylene terephthalate units. Furthermore, in this embodiment, the raw materials for the PBT resin, 1,4-butanediol or its ester-forming derivative and terephthalic acid or its ester-forming derivative (e.g., alkyl terephthalate), may be derived from either fossil resources or biomass resources. PBT resin can be used individually or in combination of two or more types.

[0016] From the viewpoint of hydrolysis resistance, the amount of terminal carboxyl groups in PBT resin is preferably 50 mmol / kg or less, more preferably 40 mmol / kg or less, and even more preferably 30 mmol / kg or less. From the viewpoint of tensile strength, the amount of terminal carboxyl groups in PBT resin is preferably 3 mmol / kg or more, more preferably 5 mmol / kg or more, and even more preferably 10 mmol / kg or more. For example, the amount of terminal carboxyl groups in PBT resin is preferably 3 to 50 mmol / kg, more preferably 5 to 40 mmol / kg, and even more preferably 10 to 30 mmol / kg.

[0017] From the viewpoint of appearance, the amount of terminal hydroxyl groups in PBT resin is preferably 40 mmol / kg or more, more preferably 60 mmol / kg or more, and even more preferably 80 mmol / kg or more. On the other hand, from the viewpoint of release properties, the amount of terminal hydroxyl groups in PBT resin is preferably 160 mmol / kg or less, more preferably 140 mmol / kg or less, and even more preferably 120 mmol / kg or less. For example, the amount of terminal hydroxyl groups in PBT resin is preferably 40 to 160 mmol / kg, more preferably 60 to 140 mmol / kg, and even more preferably 80 to 120 mmol / kg.

[0018] In this specification, the number of terminal hydroxyl groups in PBT resin is a value measured by NMR. Similarly, the number of terminal hydroxyl groups in recycled PET resin, as described later, is also a value measured by NMR. Furthermore, the number of terminal hydroxyl groups in PBT resin and recycled PET resin in polyester resin compositions, as described later, are also values ​​measured by NMR. For example, a Bruker AVANCE III 400 NMR spectrometer can be used.

[0019] The intrinsic viscosity (IV) of PBT resin is preferably 0.5 dL / g or more and 1.5 dL / g or less, more preferably 0.55 dL / g or more and 1.4 dL / g or less, and even more preferably 0.6 dL / g or more and 1.3 dL / g or less. Furthermore, the intrinsic viscosity can be adjusted by blending PBT resins having different intrinsic viscosities. For example, a PBT resin with an intrinsic viscosity of 0.9 dL / g can be prepared by blending a PBT fat with an intrinsic viscosity of 0.7 dL / g with a PBT resin with an intrinsic viscosity of 1.1 dL / g. The intrinsic viscosity (IV) of PBT resin can be measured, for example, in o-chlorophenol at a temperature of 35°C.

[0020] In PBT resin, dicarboxylic acid components (comonomer components) other than terephthalic acid and its ester-forming derivatives include, for example, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-dicarboxydiphenyl ether, etc. 8-14 Aromatic dicarboxylic acids; such as succinic acid, adipic acid, azelaic acid, sebacic acid, etc. 4-16 C alkanedicarboxylic acids; cyclohexanedicarboxylic acids, etc. 5-10 Cycloalkane dicarboxylic acids; ester-forming derivatives of these dicarboxylic acid components (C 1-6 Examples include alkyl ester derivatives and acid halides. These dicarboxylic acid components can be used individually or in combination of two or more.

[0021] Among these dicarboxylic acid components, C isophthalic acid and others 8-12 Aromatic dicarboxylic acids, and C such as adipic acid, azelaic acid, and sebacic acid. 6-12 Alkane dicarboxylic acids are more preferred.

[0022] In PBT resin, glycol components (comonomer components) other than 1,4-butanediol and its ester-forming derivatives include, for example, ethylene glycol, propylene glycol, trimethylene glycol, 1,3-butylene glycol, hexamethylene glycol, neopentyl glycol, 1,3-octanediol, etc.2-10 Alkylene glycols; polyoxyalkylene glycols such as diethylene glycol, triethylene glycol, dipropylene glycol; alicyclic diols such as cyclohexanedimethanol, hydrogenated bisphenol A; aromatic diols such as bisphenol A, 4,4'-dihydroxybiphenyl; ethylene oxide adducts of bisphenol A with 2 moles added, propylene oxide adducts of bisphenol A with 3 moles added, etc., C 2-4 alkylene oxide adducts of bisphenol A; or ester-forming derivatives (such as acetylated products) of these glycols. These glycol components can be used alone or in combination of two or more.

[0023] Among these glycol components, C 2-6 alkylene glycols such as ethylene glycol, trimethylene glycol, polyoxyalkylene glycols such as diethylene glycol, or alicyclic diols such as cyclohexanedimethanol are more preferred. As comonomer components that can be used in addition to the dicarboxylic acid component and the glycol component, for example, aromatic hydroxycarboxylic acids such as 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 4-carboxy-4'-hydroxybiphenyl; aliphatic hydroxycarboxylic acids such as glycolic acid, hydroxycaproic acid; C 3-12 lactones such as propiolactone, butyrolactone, valerolactone, caprolactone (ε-caprolactone, etc.); ester-forming derivatives of these comonomer components (C 1-6 alkyl ester derivatives, acid halides, acetylated products, etc.) are included.

[0024] All of the polybutylene terephthalate copolymers copolymerized with the comonomer components described above can be suitably used as PBT resins. Also, as the PBT resin, a combination of a homopolybutylene terephthalate polymer and a polybutylene terephthalate copolymer may be used.

[0025] PBT resin can be recycled from the market (material recycling). Alternatively, PBT resin produced by decomposing 1,4-butanediol and terephthalic acid from PBT resin waste to the monomer level (chemical recycling) and then polycondensing the resulting raw materials can also be used.

[0026] The amount of PBT resin is preferably 20% by mass or more, more preferably 25% by mass or more, and even more preferably 30% by mass or more, relative to the total amount of the polyester resin composition. On the other hand, the amount of PBT resin is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less, relative to the total amount of the polyester resin composition. For example, the amount of PBT resin is preferably 20 to 60% by mass, more preferably 25 to 50% by mass, and even more preferably 30 to 40% by mass, relative to the total amount of the polyester resin composition.

[0027] [Recycled polyethylene terephthalate resin] Recycled PET resin is made from terephthalic acid or its ester-forming derivative (C 1-6 This polyester resin is obtained by polycondensation of alkyl esters and acid halides (such as ethylene glycol) or its ester-forming derivatives (such as acetylated compounds) according to known methods, and can utilize market-recovered products such as PET bottles, PET fibers, and films.

[0028] The recycled PET resin may be modified by copolymerizing a small amount of a modifying component that provides repeating units other than terephthaloyl units and ethylenedioxy units, to the extent that it does not hinder the objectives of the present invention. The amount of repeating units other than terephthaloyl units and ethylenedioxy units contained in the recycled PET resin is preferably less than 4 mol%, more preferably 3 mol% or less, and even more preferably 2 mol% or less, of the total repeating units of the polyethylene terephthalate resin.

[0029] Furthermore, the recycled PET resin may contain 4 mol% or more of the repeating units derived from the modified components mentioned above, out of the total repeating units. In this specification, such polyethylene terephthalate resin may also be referred to as "modified PET resin".

[0030] The modified PET resin may contain other dicarboxylic acids of terephthalic acid or their ester-forming derivatives (C) to the extent that it does not impede the purpose of the present invention. 1-6 The modified polyethylene terephthalate resin may contain dicarbonyl units derived from alkyl esters, acid halides, etc. The amount of other dicarbonyl units in the modified polyethylene terephthalate resin is preferably 5 mol% to 50 mol%, more preferably 7 mol% to 30 mol%, and particularly preferably 10 mol% to 25 mol% of the total dicarbonyl units.

[0031] Suitable compounds as dicarboxylic acids or their ester-forming derivatives included in the modified component include isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-dicarboxydiphenyl ether, etc. 8-14 Aromatic dicarboxylic acids; such as succinic acid, adipic acid, azelaic acid, sebacic acid, etc. 4-16 C alkanedicarboxylic acids; cyclohexanedicarboxylic acids, etc. 5-10 Cycloalkane dicarboxylic acids; ester-forming derivatives of these dicarboxylic acid components (C 1-6 Examples include alkyl ester derivatives and acid halides. These dicarboxylic acids can be used individually or in combination of two or more.

[0032] Among these dicarboxylic acids or their esterifying derivatives, C such as isophthalic acid 8-12 Aromatic dicarboxylic acids or their ester-forming derivatives, as well as C such as adipic acid, azelaic acid, and sebacic acid. 6-12Alkane dicarboxylic acids or their ester-forming derivatives are more preferred. Furthermore, since the resulting polybutylene terephthalate resin composition exhibits excellent metal adhesion and mechanical properties, isophthalic acid or ester-forming derivatives of isophthalic acid (such as dimethyl isophthalate, diethyl isophthalate, and dichloride isophthalate) are particularly preferred as the dicarboxylic acid or its ester-forming derivative in the modified component.

[0033] The modifying components used in the production of the modified PET resin may contain, in addition to a predetermined amount of dicarboxylic acid or its ester-forming derivative, other glycol components, hydroxycarboxylic acid components, lactone components, etc., of ethylene glycol and its ester-forming derivatives, to the extent that they do not impede the objectives of the present invention. In the modified polyethylene terephthalate resin composition, the amount of repeating units derived from these modifying components, such as glycol components, hydroxycarboxylic acid components, and lactone components, is preferably 30 mol% or less, more preferably 25 mol% or less, and particularly preferably 20 mol% or less, of the total repeating units in the modified polyethylene terephthalate resin.

[0034] Glycol components included in the modified components include propylene glycol, trimethylene glycol, 1,4-butanediol, 1,3-butylene glycol, hexamethylene glycol, neopentyl glycol, 1,3-octanediol, and other C 2-10 Alkylene glycols; polyoxyalkylene glycols such as diethylene glycol, triethylene glycol, and dipropylene glycol; alicyclic diols such as cyclohexanedimethanol and hydrogenated bisphenol A; aromatic diols such as bisphenol A and 4,4'-dihydroxybiphenyl; bisphenol A C, such as a 2-mol ethylene oxide adduct of bisphenol A and a 3-mol propylene oxide adduct of bisphenol A. 2-4 Examples include alkylene oxide adducts of these glycols; or ester-forming derivatives of these glycols (such as acetylated compounds). These glycol components can be used individually or in combination of two or more.

[0035] The hydroxycarboxylic acid components included in the modified components are aromatic hydroxycarboxylic acids such as 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, and 4-carboxy-4'-hydroxybiphenyl; aliphatic hydroxycarboxylic acids such as glycolic acid and hydroxycaproic acid; or ester-forming derivatives of these hydroxycarboxylic acids (C 1-6 Examples include alkyl ester derivatives, acid halides, acetylated compounds, etc. These hydroxycarboxylic acid components can be used individually or in combination of two or more.

[0036] The lactone components included in the modified components are propiolactone, butyrolactone, valerolactone, caprolactone (ε-caprolactone, etc.), etc. 3-12 Lactones are one example. These lactone components can be used individually or in combination of two or more.

[0037] From the viewpoint of appearance, the amount of terminal hydroxyl groups in recycled PET resin is preferably 10 mmol / kg or more, more preferably 20 mmol / kg or more, and even more preferably 30 mmol / kg or more. On the other hand, from the viewpoint of release properties, the amount of terminal hydroxyl groups in PET resin is preferably 80 mmol / kg or less, more preferably 70 mmol / kg or less, and even more preferably 60 mmol / kg or less. For example, the amount of terminal hydroxyl groups in PET resin is preferably 10 to 80 mmol / kg, more preferably 20 to 70 mmol / kg, and even more preferably 30 to 60 mmol / kg.

[0038] If the amount of terminal hydroxyl groups in recycled PET resin recovered from the market falls outside the aforementioned range, the amount of terminal hydroxyl groups may be adjusted by solid-phase polymerization in an inert gas atmosphere such as nitrogen. Furthermore, PET resin produced by decomposing PET resin waste down to monomer levels such as ethylene glycol and terephthalic acid, and then polycondensing the resulting raw materials, can also be used. Recycled PET resin may be used individually or in combination of two or more types.

[0039] The amount of recycled PET resin is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more, relative to the total amount of the polyester resin composition. On the other hand, the amount of recycled PET resin is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less, relative to the total amount of the polyester resin composition. For example, the amount of PET resin is preferably 10 to 50% by mass, more preferably 20 to 45% by mass, and even more preferably 25 to 40% by mass, relative to the total amount of the polyester resin composition.

[0040] From the viewpoint of improving mold release properties, in a polyester resin composition, the amount of terminal hydroxyl groups of PBT resin relative to the total amount of PBT resin and recycled PET resin (sum of the mass of PBT resin and the mass of PET resin) is preferably 30 to 70 mmol / kg. In a polyester resin composition, the amount of terminal hydroxyl groups of PBT resin relative to the total amount of PBT resin and recycled PET resin is more preferably 35 to 65 mmol / kg, and even more preferably 40 to 60 mmol / kg.

[0041] In a polyester resin composition, the amount of terminal hydroxyl groups of PBT resin relative to the total amount of PBT resin and recycled PET resin is preferably 70 mmol / kg or less, more preferably 65 mmol / kg or less, and even more preferably 60 mmol / kg or less. On the other hand, in a polyester resin composition, the amount of terminal hydroxyl groups of PBT resin relative to the total amount of PBT resin and recycled PET resin is preferably 30 mmol / kg or more, more preferably 35 mmol / kg or more, and even more preferably 40 mmol / kg or more.

[0042] From the viewpoint of further improving mold release properties, in the polyester resin composition, the sum of the terminal hydroxyl groups of the PBT resin and the recycled PET resin relative to the total amount of PBT resin and recycled PET resin is preferably 60 to 90 mmol / kg, more preferably 62 to 85 mmol / kg, even more preferably 65 to 75 mmol / kg, and still more preferably 70 to 75 mmol / kg.

[0043] In a polyester resin composition, the sum of the terminal hydroxyl groups of the PBT resin and the recycled PET resin relative to the total amount of PBT resin and recycled PET resin is preferably 90 mmol / kg or less, more preferably 85 mmol / kg or less, and even more preferably 75 mmol / kg or less. On the other hand, in a polyester resin composition, the sum of the terminal hydroxyl groups of the PBT resin and the recycled PET resin relative to the total amount of PBT resin and recycled PET resin is preferably 60 mmol / kg or more, more preferably 62 mmol / kg or more, even more preferably 65 mmol / kg or more, and even more preferably 70 mmol / kg or more.

[0044] [Transesterification inhibitors] From the viewpoint of suppressing transesterification reactions, polyester resin compositions preferably contain transesterification inhibitors. Examples of transesterification inhibitors include organic phosphite compounds, phosphate compounds, and phosphorus compounds such as metal phosphate salts. Specific examples include bis(2,4-di-t-4 methylphenyl)pentaerythritol diphosphite, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, tetrakis(2,4-di-t-butylphenyl)-4,4'-biphenylene phosphate, and 3,9-bis(2,6-di-t-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro-[5.5]undecane. Examples of metal phosphate salts include alkaline earth metal phosphates such as monocalcium phosphate (calcium dihydrogen phosphate) and alkali metal phosphates such as monosodium phosphate (sodium dihydrogen phosphate). The metal phosphate salt may be, for example, an anhydrous form or a hydrated form. From the viewpoint of further improving mold release properties, the polyester resin composition preferably contains a phosphorus-based compound containing a sodium atom or a calcium atom, and more preferably contains a metal phosphate salt containing a sodium atom or a calcium atom.

[0045] In the polyester resin composition, the transesterification inhibitor is preferably present in an amount of 0.03 to 0.5% by mass, and more preferably in an amount of 0.1 to 0.5% by mass, relative to the total amount of the polyester resin composition. For example, in a polyester resin composition, the amount of phosphorus-based compounds containing sodium atoms or calcium atoms is preferably 0.1 to 0.5% by mass, and more preferably 0.15 to 0.3% by mass, relative to the total amount of the polyester resin composition.

[0046] [Flame retardant] In this embodiment, it is preferable to use a halogen-based flame retardant and / or a phosphorus-based flame retardant as the flame retardant. As the halogen-based flame retardant, it is more preferable to use a brominated aromatic flame retardant containing a structure in which one or more hydrogen atoms of the benzene ring are substituted with bromine atoms. Specifically, examples include brominated epoxy compounds, brominated polystyrene, brominated acrylate polymers, brominated polycarbonates, brominated phthalimides, and brominated polyphenylene ethers. As the phosphorus-based flame retardant, there are no particular limitations as long as it is a compound containing phosphorus atoms, but examples include inorganic phosphorus-based flame retardants and organophosphorus-based flame retardants. Examples of organophosphorus-based flame retardants include monomer-type organophosphorus compounds and polymer-type organophosphorus compounds. The amount of the flame retardant depends on the halogen and phosphorus content, but is preferably 6 to 20% by mass, more preferably 10 to 18% by mass, and even more preferably 12 to 17% by mass, relative to the total amount of the polyester resin composition.

[0047] (Halogenated flame retardant) As the brominated epoxy compound, an aromatic epoxy compound containing one or more epoxy groups in one molecule (such as biphenyl-type epoxy compounds, bisphenol A-type epoxy compounds, phenol novolac-type epoxy compounds, and cresol novolac-type epoxy compounds) is used, and it is preferable to use one with a number average molecular weight of 1,000 to 20,000. From the viewpoint of the moldability of the flame-retardant polybutylene terephthalate resin composition, it is more preferable that the number average molecular weight is 2,000 to 15,000, and even more preferable that it is 3,000 to 10,000.

[0048] Furthermore, it is preferable to use the above-mentioned brominated epoxy compound with its ends sealed with bromophenol (tribromophenol, etc.) because this suppresses a decrease in the fluidity of the flame-retardant polybutylene terephthalate resin composition.

[0049] Brominated polystyrene may be produced by either brominating polystyrene or by polymerizing brominated styrene monomer, but polymerized brominated styrene is preferred because it contains a small amount of free bromine (atoms). The hydrogen atoms of the vinyl group to which brominated benzene is bonded may be substituted with methyl groups. Brominated polystyrene may also be a copolymer of other vinyl monomers. Examples of vinyl monomers in this case include styrene, α-methylstyrene, acrylonitrile, methyl acrylate, butadiene, and vinyl acetate. Brominated polystyrene may also be used as a single substance or a mixture of two or more substances with different structures, and may contain units derived from styrene monomers with different numbers of bromine atoms in a single molecular chain.

[0050] Specific examples of brominated polystyrene include, for example, poly(4-bromostyrene), poly(2-bromostyrene), poly(3-bromostyrene), poly(2,4-dibromostyrene), poly(2,6-dibromostyrene), poly(2,5-dibromostyrene), poly(3,5-dibromostyrene), poly(2,4,6-tribromostyrene), poly(2,4,5-tribromostyrene), poly(2,3,5-tribromostyrene), and poly(4-bromo-α-methylstyrene). Examples include poly(2,4-dibromo-α-methylstyrene), poly(2,5-dibromo-α-methylstyrene), poly(2,4,6-tribromo-α-methylstyrene), and poly(2,4,5-tribromo-α-methylstyrene), with poly(2,4,6-tribromostyrene), poly(2,4,5-tribromostyrene), and polydibromostyrene and polytribromostyrene containing an average of 2 to 3 bromine groups in the benzene ring being particularly preferred.

[0051] Examples of brominated acrylate polymers include those represented by the following general formula (I). [ka] In the formula, at least one of X is bromine. The number of X in a single constituent unit is 1 to 5, but it is preferably 3 to 5 for the effect of flame retardancy. The average degree of polymerization m is 10 to 2000, preferably in the range of 15 to 1000. If the average degree of polymerization is low, the thermal stability deteriorates, and if it exceeds 2000, the moldability of the flame-retardant polybutylene terephthalate resin composition to which it is added deteriorates. In addition, one or more of the above brominated acrylate polymers may be used.

[0052] Brominated acrylate polymers represented by general formula (I) can be obtained by polymerizing bromine-containing benzyl acrylate alone, but copolymerization with benzyl methacrylate or other polymers with similar structures is also possible. Examples of bromine-containing benzyl acrylates include pentabromobenzyl acrylate, tetrabromobenzyl acrylate, tribromobenzyl acrylate, or mixtures thereof. Among these, pentabromobenzyl acrylate is preferred. Examples of benzyl methacrylates that can be copolymerized include methacrylates corresponding to the above-mentioned acrylates. Furthermore, copolymerization with vinyl monomers is also possible, and examples include acrylic acid esters such as acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, and benzyl acrylate; methacrylic acid esters such as methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, and benzyl methacrylate; unsaturated carboxylic acids or their anhydrides such as styrene, acrylonitrile, fumaric acid, and maleic acid; vinyl acetate; vinyl chloride, etc. In addition, crosslinkable vinyl monomers, xylylenediacrylate, xylylenedimethacrylate, tetrabrom xylylenediacrylate, tetrabrom xylylenedimethacrylate, butadiene, isoprene, and divinylbenzene can also be used. These are used in amounts equal to or less than equimolar to benzyl acrylate or benzyl methacrylate, preferably 0.5 times the molar amount or less.

[0053] The brominated polycarbonate is preferably, for example, a brominated polycarbonate obtained from brominated bisphenol A, particularly tetrabromobisphenol A. Its terminal structure may include a phenyl group, a 4-t-butylphenyl group, or a 2,4,6-tribromophenyl group, with a 2,4,6-tribromophenyl group being particularly preferred.

[0054] The average number of repeating carbonate units in brominated polycarbonate can be appropriately selected and determined, but it is usually between 2 and 30. If the average number of repeating carbonate units is too small, it may cause a decrease in the molecular weight of the PBT resin during melting. Conversely, if it is too large, the melt viscosity will increase, and moldability may deteriorate. Therefore, the average number of repeating units is preferably between 3 and 15, and especially between 3 and 10.

[0055] The molecular weight of the brominated polycarbonate is arbitrary and can be selected and determined as appropriate, but preferably, the viscosity-average molecular weight is 1,000 to 20,000, and more preferably, 2,000 to 10,000.

[0056] The brominated polycarbonate obtained from the above-mentioned brominated bisphenol A can be obtained, for example, by a conventional method of reacting brominated bisphenol A with phosgene. Examples of end-capping agents include aromatic monohydroxy compounds, which may be substituted with halogens or organic groups.

[0057] Examples of brominated phthalimides include N,N'-(bistetrabromophthalimide)ethane, N,N'-(bistetrabromophthalimide)propane, N,N'-(bistetrabromophthalimide)butane, N,N'-(bistetrabromophthalimide)diethyl ether, N,N'-(bistetrabromophthalimide)dipropyl ether, N,N'-(bistetrabromophthalimide)dibutyl ether, N,N'-(bistetrabromophthalimide)diphenylsulfone, N,N'-(bistetrabromophthalimide)diphenyl ketone, and N,N'-(bistetrabromophthalimide)diphenyl ether. Among these, N,N'-ethylenebis(tetrabromophthalimide) is preferred.

[0058] In this embodiment, when a halogenated flame retardant is used in the polyester resin composition, an antimony compound or a metal borate salt may be included as a flame retardant aid. Typical antimony compounds used as flame retardant aids include antimony trioxide, antimony tetroxide, antimony pentoxide, and sodium antimonate. Examples of metal borate salts include calcium borate and zinc borate.

[0059] (Phosphorus-based flame retardant) Among phosphorus-based flame retardants, inorganic phosphorus-based flame retardants include, for example, red phosphorus and (poly)phosphates [such as orthophosphoric acid, phosphorous acid, hypophosphoric acid, polyphosphoric acid (metaphosphoric acid, pyrophosphoric acid, triphosphoric acid, tetraphosphoric acid, etc.), and ammonium salts of non-condensed or condensed (phosphorous) phosphoric acid (metaphosphoric acid, pyrophosphoric acid, etc.)].

[0060] Red phosphorus has a high flame-retardant effect and can impart flame retardancy to resins even in small amounts. Furthermore, because the effect is obtained with small amounts, flame retardancy can be achieved without impairing the properties of the resin (e.g., mechanical properties or electrical properties). Stabilized red phosphorus is usually preferred as the red phosphorus used. In particular, red phosphorus obtained by a method of micronizing red phosphorus without crushing it and without forming a crushed surface that is highly reactive with water and oxygen on the surface of the red phosphorus, and red phosphorus in which the surface of the red phosphorus is coated with resin (e.g., thermosetting resin, thermoplastic resin), metal, metal compound (e.g., metal hydroxide, metal oxide, etc.), either alone or in combination of two or more, can be used.

[0061] Examples of thermosetting resins used to coat the surface of red phosphorus include phenolic resins, melamine resins, urea resins, alkyd resins, unsaturated polyester resins, epoxy resins, and silicone resins. Examples of thermoplastic resins include polyester resins, polyamide resins, acrylic resins, and olefin resins. Examples of metal hydroxides include aluminum hydroxide, magnesium hydroxide, calcium hydroxide, zinc hydroxide, and titanium hydroxide. Examples of metal oxides include aluminum oxide, magnesium oxide, zinc oxide, titanium oxide, zirconium oxide, copper oxide, iron oxide, molybdenum oxide, tungsten oxide, manganese oxide, and tin oxide.

[0062] Furthermore, methods for stabilizing the surface of red phosphorus by coating it with metal include, for example, electroless plating to coat it with metal (iron, nickel, copper, aluminum, zinc, manganese, tin, titanium, zirconium, etc.) or alloys thereof. Other methods for coating the surface of red phosphorus include treating the red phosphorus with a solution of metal salt (salts of aluminum, magnesium, zinc, titanium, copper, silver, iron, nickel, etc.) to form a metal phosphorus compound on the surface of the red phosphorus and stabilize it.

[0063] In particular, a method may be used to atomize red phosphorus without forming a fractured surface on the red phosphorus surface, and a coating treatment may be performed in multiple layers by combining a coating of metal components (metal hydroxide or metal oxide) and a resin coating, or in particular, multiple layers of resin coating may be applied on top of the coating of metal components. These stabilized red phosphorus have excellent heat resistance and hydrolysis resistance, and the generation of phosphine due to decomposition reactions in the presence of moisture or at high temperatures is significantly reduced, which is preferable from a safety viewpoint when manufacturing the resin composition of the present invention and when manufacturing molded articles.

[0064] For red phosphorus, stabilized red phosphorus can usually be used in powder form. The particle size of stabilized red phosphorus is, for example, 0.01 to 100 μm, preferably 0.1 to 70 μm, and more preferably about 0.1 to 50 μm.

[0065] Monomer-type organophosphorus compounds used as organophosphorus flame retardants include phosphate esters, phosphate ester amides, phosphonitrile compounds, polyphosphates, organophosphonic acid compounds (phosphonic acid esters, metal salts, etc.), organophosphinic acid compounds, and phosphine oxides (triphenylphosphine oxide, tricresylphosphine oxide, etc.).

[0066] Examples of phosphate esters include aliphatic phosphate esters such as trimethyl phosphate, triethyl phosphate, tripropyl phosphate, triisopropyl phosphate, tributyl phosphate, triisobutyl phosphate, pentaerythritol phosphate (e.g., Great Lakes Chemical's NH-1197, bicyclophosphate ester, etc.) and tri-C phosphate. 1-10 Alkyl esters; diC phosphate corresponding to the phosphate triester mentioned above. 1-10 Alkyl esters and mono-C phosphates 1-10 Alkyl esters, etc., aromatic phosphate esters [triphenyl phosphate, tricresyl phosphate, trixylyl phosphate, diphenylcresyl phosphate, tri(isopropylphenyl) phosphate, etc.] 6-20Examples include aryl esters, aliphatic-aromatic phosphate esters, methyldiphenyl phosphate, phenyldiethyl phosphate, spirocyclic aromatic phosphate esters (such as diphenylpentaerythritol diphosphate, dicresylpentaerythritol diphosphate, and dixylpentaerythritol diphosphate).

[0067] As the phosphate ester amide, compounds containing phosphate ester and phosphate amide bonding modes can be used.

[0068] Preferred phosphate ester amides include condensed phosphate ester amides. Examples of such phosphate ester amides include N-(diaryloxyphosphinnyl)-substituted alkyleneamines [e.g., N,N′-bis(diphenoxyphosphinnyl)piperazine, N,N′-bis(ditolyloxyphosphinnyl)piperazine, N,N′-bis(dixyloxyphosphinnyl)piperazine, N,N′-bis(di or trimethylphenyloxyphosphinnyl)piperazine, etc.], and bis to tetrakis[(diaryloxyphosphinnyl)amino]-substituted aromatic compounds {e.g., 1,3- or 1,4-bis [(diphenoxyphosphinnyl)amino]benzene, 1,3- or 1,4-bis[(ditolyloxyphosphinnyl)amino]benzene, 1,3- or 1,4-bis[(dixyloxyphosphinnyl)amino]benzene, 1,3- or 1,4-bis[(di or trimethylphenyloxyphosphinnyl)amino]benzene, 1,3- or 1,4-bis[(diphenoxyphosphinnyl)aminomethyl]benzene, 1,3- or 1,4-bis[( [dixyloxyphosphinyl)aminomethyl]benzene, 1,3- or 1,4-bis[(di-trimethylphenyloxyphosphinyl)aminomethyl]benzene, etc.}, N-(cyclic alkylenedioxyphosphinyl)substituted alkyleneamines [e.g., N,N′-bis(neopentylenedioxyphosphinyl)piperazine, etc.], bis to tetrakis[(cyclic alkylenedioxyphosphinyl)amino]substituted aromatic compounds {e.g., 1,3- or 1,4-bis[(neopentylenedioxyphosphinyl)amino]benzene, 1, 3- or 1,4-bis[(neopentylenedioxyphosphinyl)aminomethyl]benzene, etc., N-(cyclic ariadioxyphosphinyl)-substituted alkyleneamines [e.g., N,N′-bis(phenylene-1,2-dioxyphosphinyl)piperazine, 1,3- or 1,4-bis[(biphenylene-2,2′-dioxyphosphinyl)aminomethyl]piperazine, etc.], bis to tetrakis[(cyclic ariadioxyphosphinyl)amino]-substituted aromatic compounds {e.g., 1,3- or 1,4-bis[(phenylene-1,This includes 2-dioxyphosphinnyl)amino]benzene, 1,3- or 1,4-bis[(biphenylene-2,2′-dioxyphosphinnyl)aminomethyl]benzene, 3,9-bis(N-substituted amino)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]-undecane-3,9-dioxides [for example, spirocyclic phosphate ester amides in which the N-substituted amino group is a dialkylamino group (such as diethylamino), a cyclic amino group (such as piperidino, pipecolino, dimethylpiperidino, or morpholino), an arylamino group (such as phenylamino), or an alkylarylamino group (such as methylphenylamino)].

[0069] Examples of phosphonitrile compounds include cyclic or linear aryloxyphosphazenes such as (poly)phenoxyphosphazene, (poly)tolyloxyphosphazene, (poly)xylenyloxyphosphazene, and (poly)methylnaphthyloxyphosphazene; cyclic or linear alkoxyaryloxyphosphazenes such as (poly)methoxyphenoxyphosphazene, (poly)methoxytolyloxyphosphazene, and (poly)methoxynaphthyloxyphosphazene; and cyclic or linear alkoxyphosphazenes such as (poly)methoxyphosphazene.

[0070] Examples of organic phosphonic acid (phosphite) compounds include aromatic phosphite esters (where the aryl group is phenyl, cresyl, xylyl, etc., such as tri-C phosphite). 6-20 (such as aryl esters), aliphatic phosphite esters (tri-C phosphite where the alkyl group is methyl, ethyl, propyl, butyl, t-butyl, hexyl, etc.) 1-10 Alkyl esters; di or mono C phosphorous esters corresponding to the trialkyl phosphites mentioned above. 1-10 C(alkyl esters, etc.), organic phosphite esters [for example, C(alkyl) is the alkyl(alkyl) example above, and the aryl(aryl) is phenyl, cresyl, xylyl, etc.] 1-6 DiC alkylphosphonate 1-6 Alkyl, C 1-6 DiC alkylphosphonate 6-10 Ariel, C 1-6Alkylphosphonic acid C 1-6 Alkyl C 6-10 Alkylphosphonic acid diesters such as aryls; C corresponding to the alkylphosphonic acid diester. 6-10 Aryl-phosphonic acid diesters; cyclic organic phosphonic acid diesters {e.g., 4-C1-6 alkyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]-octane-1-oxide such as 4-methyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]-octane-1-oxide, spirocyclic alkylphosphonic acid esters such as pentaerythritol bis(methylphosphonate), pentaerythritol bis(ethylphosphonate), pentaerythritol bis(propylphosphonate), pentaerythritol bis(butylphosphonate), spirocyclic cycloalkylphosphonic acid esters such as pentaerythritol bis(cyclohexylphosphonate), spirocyclic aralkylphosphonic acid esters such as pentaerythritol bis(benzylphosphonate), spirocyclic arylphosphonic acid esters such as pentaerythritol bis(phenylphosphonate), pentaerythritol bis(tolylphosphonate), etc.}; C 6-15 Arylphosphonic acid monoesters (e.g., 10-hydroxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide); phosphonocarboxylic acid esters (C corresponding to the alkylphosphonic acid diesters such as dimethyl methoxycarbonylmethylphosphonate) 1-4 Alkoxycarbonyloxy C 1-4This includes various phosphonic acid esters, such as phosphonocarboxylic acid triesters (including alkylphosphonic acid diesters). It also includes phosphorous acid, (cyclic) phosphorous acid monoesters, or metal salts (Ca, Mg, Zn, Ba, Al salts, etc.) of phosphonocarboxylic acids (e.g., alkylphosphonic acid, alkylphosphonic acid monoalkyl ester, alkylphosphonic acid monoaryl ester, arylphosphonic acid, arylphosphonic acid monoalkyl ester, arylphosphonic acid monoaryl ester, etc.) which may be substituted with alkyl or aryl groups. Specific examples of phosphonic acid esters include, for example, diphenyl methanephosphonate and diethyl phenylphosphonate.

[0071] Organic phosphinic acid compounds include alkyl groups (C 1-4 (Alkyl group, etc.) or aryl group (C 6-10 Phosphinic acid esters (such as methyl phosphinate) may be substituted (monosubstituted or disubstituted) with an aryl group or other group. 1-6 C phosphinates such as alkyl and phenyl phosphinates 6-10 Aryl, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-C 1-30 Alkyl or C 6-20 This includes cyclic phosphinic acid esters such as aryl-substituted-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide. It also includes metal salts (Ca, Mg, Zn, Ba, Al salts, etc.) of phosphinic acids that may be substituted with alkyl or aryl groups (e.g., dimethylphosphinic acid, diethylphosphinic acid, methylethylphosphinic acid, etc.), phosphinicocarboxylic acid esters (e.g., 3-methylphosphinicopropionate, 3-phenylphosphinicopropionate, etc.), and their homopolymers and copolymers.

[0072] As polymer-type organophosphorus compounds, condensates of monomer-type organophosphorus compounds can be used. The condensates include polymer-type phosphate esters, and examples include resorcinol phosphates (condensates of resorcinol and phenyl phosphate, condensates of resorcinol and cresyl phosphate, condensates of resorcinol and xylyl phosphate, etc.), hydroquinone phosphates (condensates of hydroquinone and phenyl phosphate, condensates of hydroquinone and cresyl phosphate, condensates of hydroquinone and xylenyl phosphate, etc.), biphenol phosphates (condensates of biphenol and phenyl phosphate, condensates of biphenol and cresyl phosphate, condensates of biphenol and xylenyl phosphate, etc.), and bisphenol phosphates (condensates of bisphenol A and phenyl phosphate, condensates of bisphenol A and cresyl phosphate, condensates of bisphenol A and xylenyl phosphate, etc.).

[0073] Furthermore, polymer-type organophosphorus compounds may also be phosphate esters of polymers having hydroxyl groups (such as phenolic resins). In addition, polymer-type organophosphorus compounds also include polyphosphenicocarboxylic acid esters and polyphosphonic acid amides.

[0074] Preferred phosphorus-based flame retardants include inorganic phosphorus compounds (e.g., red phosphorus, ammonium (poly)phosphate, etc.), phosphate esters (e.g., aliphatic phosphate esters, aromatic phosphate esters and condensed phosphate esters, especially condensed phosphate esters), phosphate ester amides, phosphonitrile compounds, organic phosphonic acid compounds (e.g., phosphaphenanthrenes, etc.), and organic phosphinic acid compounds (e.g., dialkylphosphinate metal salts, etc.).

[0075] In this embodiment, the polyester resin composition may contain a nitrogen-containing compound as a flame retardant aid when a phosphorus-based flame retardant is used. Examples of nitrogen-containing compounds include nitrogen-containing cyclic compounds having an amino group, salts of nitrogen-containing cyclic compounds having an amino group and (iso)cyanuric acid, salts of nitrogen-containing cyclic compounds having an amino group and oxygen acids, salts of nitrogen-containing cyclic compounds having an amino group and organophosphates, polyphosphate amides, urea compounds, amidine compounds, tetrazole compounds, and the like. Particularly preferred are melamine salts of cyanuric acid such as melamine cyanurate, and melamine salts, melam salts, melon salts, guanamine salts, and the like corresponding to melamine salts.

[0076] In this embodiment, the polyester resin composition may also use a drip-preventing agent such as polytetrafluoroethylene in combination with the flame retardant and flame retardant aid to prevent the spread of fire due to the dripping of burnt resin.

[0077] [Crystallizing agent] From the viewpoint of promoting the crystallization of the resin, the polyester resin composition preferably contains a crystal nucleating agent. The nucleating agent may be an organic substance, an inorganic substance, or a combination thereof. Inorganic substances can be, for example, individual elements such as Zn powder, Al powder, graphite, and carbon black; metal oxides such as ZnO, MgO, Al2O3, TiO2, MnO2, SiO2, and Fe3O4; nitrides such as aluminum nitride, silicon nitride, titanium nitride, and boron nitride; inorganic salts such as Na2CO3, CaCO3, MgCO3, CaSiO3, BaSO4, and Ca3(PO4)3; and clays such as talc, kaolin, clay, and white clay, either alone or in combination of two or more. Organic substances can be, for example, organic salts such as calcium oxalate, sodium oxalate, calcium benzoate, calcium phthalate, calcium tartrate, magnesium stearate, and polyacrylates; polymers such as polyester, polyethylene, and polypropylene; and crosslinked polymers, either alone or in combination of two or more. Among these, talc, carbon black, or combinations thereof are preferred.

[0078] In the polyester resin composition, the amount of the nucleating agent is preferably 0.05 to 2% by mass, more preferably 0.1 to 1.5% by mass, and even more preferably 0.3 to 1% by mass, based on the total amount of the polyester resin composition.

[0079] [Inorganic filler] The polyester resin composition preferably contains an inorganic filler. A fibrous inorganic filler is preferred as the inorganic filler.

[0080] 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. The type of glass used as the raw material for glass fibers is not particularly limited, but for quality reasons, E-glass and corrosion-resistant glass containing zirconium in its composition are preferred.

[0081] In the polyester resin composition, the inorganic filler is preferably 5 to 50% by mass, and more preferably 10 to 40% by mass, relative to the total amount of the polyester resin composition.

[0082] [Other ingredients] The polyester resin composition may contain other components as needed. Examples of other components include, but are not limited to, antioxidants, weather stabilizers, molecular weight modifiers, ultraviolet absorbers, antistatic agents, lubricants, crystallization accelerators such as plasticizers, and colorants.

[0083] [Method for producing polyester resin composition] The method for producing the polyester resin composition is not particularly limited. The polyester resin composition can be produced by various methods known as methods for producing thermoplastic resin compositions.

[0084] A suitable method for producing a polyester resin composition is, for example, a method in which each component is melt-kneaded using a melt-kneading device such as a single-screw or twin-screw extruder and then extruded into pellets.

[0085] <Resin molded products> The resin molded article of this embodiment can be obtained using the polyester resin composition described above.

[0086] There are no particular limitations on the method for producing resin molded products using a polyester resin composition, and known methods can be employed. For example, the polyester resin composition 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.

[0087] The resin composition of this embodiment exhibits excellent mold release properties and superior productivity of molded resin products. Furthermore, molded resin products obtained using this resin composition exhibit reduced post-shrinkage under high-temperature conditions and can be suitably used as molded products exposed to high-temperature and high-humidity environments for long periods, such as in automobiles, trains, and the aerospace industry. The molded resin products of this embodiment can be used in connectors, sensors, actuators, ECU housings, levers, switches, relays, and the like.

[0088] Embodiments of the present invention include, but are not limited to, the following embodiments. <1> A polyester resin composition comprising polybutylene terephthalate resin, recycled polyethylene terephthalate resin, a transesterification inhibitor, and a flame retardant, wherein the amount of terminal hydroxyl groups of the polybutylene terephthalate resin is 30 to 70 mmol / kg relative to the total amount of the polybutylene terephthalate resin and the recycled polyethylene terephthalate resin. <2> With respect to the total amount of the polybutylene terephthalate resin and the polyethylene terephthalate resin, the sum of the terminal hydroxyl groups of the polybutylene terephthalate resin and the polyethylene terephthalate resin is 60 to 90 mmol / kg. <1> The polyester resin composition described above. <3> The transesterification inhibitor comprises a phosphorus compound containing a sodium atom or a calcium atom. <1> or <2> The polyester resin composition described above. <4> Further containing a crystal nucleating agent, <1> ~ <3> A polyester resin composition according to any one of the items. <5> The polyester resin composition further comprises 5 to 50% by mass of an inorganic filler, <1> ~ <4> A polyester resin composition according to any one of the items. <6> <1> ~ <5> A resin molded article obtained using the polyester resin composition described in any one of the items. [Examples]

[0089] The embodiment will be described in more detail below with reference to examples, but this embodiment is not limited to the following examples.

[0090] [Examples 1-9, Comparative Examples 1-3] The materials listed in Tables 1-3 were melt-kneaded and extruded in the ratios (mass%) shown in Tables 1-3 using a 30 mmφ twin-screw extruder (TEX30, manufactured by Japan Steel Works Ltd.) at a cylinder temperature of 260°C and a screw rotation speed of 130 rpm to obtain pellets consisting of the polyester resin compositions of Examples 1-9 and Comparative Examples 1-3. Details of each component shown in Tables 1-3 are given below.

[0091] (1)PBT resin (A) (A-1): PBT resin: Manufactured by Polyplastics Co., Ltd., terminal hydroxyl group content 80 mmol / kg (A-2): PBT resin, manufactured by Polyplastics Co., Ltd., terminal hydroxyl group content 100 mmol / kg (A-3): PBT resin, manufactured by Polyplastics Co., Ltd., terminal hydroxyl group content 120 mmol / kg

[0092] (2) Recycled PET resin (B) (B-1): PET resin, Indorama N1-100, terminal hydroxyl group content 40 mmol / kg

[0093] (4) Transesterification inhibitors (C) (C-1): Sodium dihydrogen phosphate, manufactured by Yoneyama Chemical Industries, Ltd.

[0094] (5) Flame retardant (D) (D-1): Brominated epoxy compound, "SRT5000S" manufactured by Sakamoto Pharmaceutical Co., Ltd. (D-2): Brominated polystyrene, Albemarle "Pyrocheck 68PBC" (D-3): Brominated acrylate polymer, "FR-1025" manufactured by ICL Japan. (D-4): Organophosphinate compound, Clariant Japan "EXOLIT OP1240"

[0095] (6) Flame retardant additive (E) (E-1): Antimony pentoxide, manufactured by Nissan Chemical Industries, Ltd., "Sun Epoch NA1030" (E-2): Antimony trioxide, manufactured by Nippon Seikou Co., Ltd., "ATOX-S" (E-3): Melamine cyanurate, BASF Japan "MELAPUR MC50"

[0096] (7) Drip prevention agent (F) (F-1): Polytetrafluoroethylene, Daikin Industries' "Polyflon PTFE M-392"

[0097] (8) Inorganic filler (G) (G-1): Fiberglass, manufactured by Nippon Electric Glass Co., Ltd., "ECS 03 T-187"

[0098] (9) Lubricant (H) (H-1): Low molecular weight polyethylene, manufactured by Sanyo Chemical Industries, Ltd., "Sunwax 161-P"

[0099] (10) Nucleating agent (I) (I-1): Boron Nitride, manufactured by Mizushima Alloy Iron FS-1

[0100] In Tables 1 and 2, "PBT terminal hydroxyl group amount (mmol / kg)" refers to the amount of terminal hydroxyl groups in PBT resin (A) relative to the total amount of PBT resin (A) and recycled PET resin (B) in the polyester resin composition (mmol / kg). "PET terminal hydroxyl group amount (mmol / kg)" refers to the amount of terminal hydroxyl groups in PET resin (B) relative to the total amount of PBT resin (A) and recycled PET resin (B) in the polyester resin composition (mmol / kg). "Total terminal hydroxyl group amount (mmol / kg)" refers to the sum of the terminal hydroxyl groups in PBT resin (A) and recycled PET resin (B) relative to the total amount of PBT resin (A) and recycled PET resin (B) in the polyester resin composition (mmol / kg). The terminal hydroxyl group amounts of PBT resin (A) and recycled PET resin (B) in the polyester resin composition were measured by NMR using a Bruker AVANCE III 400 NMR spectrometer.

[0101] <Evaluation Method>

[0102] (1) Cooling time (release properties) For the resin compositions listed in Tables 1 and 2, molded products with the shape shown in Figure 1 were produced using Toshiba Corporation's "EC40" resin, and the minimum time required for demolding (cooling time (seconds)) at a holding pressure of 70 MPa was measured. A shorter cooling time indicates superior demolding performance. The results (cooling time (seconds)) are shown in Tables 1 and 2. The molding conditions are as follows:

[0103] (Molding conditions) Cylinder temperature: 250℃ Mold temperature: 60℃ Injection speed: 20mm / sec Injection and holding pressure: 5 seconds

[0104] Figure 1 is a schematic perspective view of a molded product used to evaluate the cooling time (release properties). In Figure 1, 1 is the molded product, 2 is the short side, 3 is the cylinder, 4 is the long side, and 5 is the ejector pin protrusion area. The molded product 1 has a thin T-shape (long side 4: length 30 mm, width 15 mm, thickness 1 mm; short side 2: height 10 mm, width 15 mm, central thickness 2 mm, maximum thickness 3 mm), and a cylinder 3 (diameter 3 mm, height 7 mm) is installed on one side of the long side 4. Furthermore, an ejector pin (not shown) is set to protrude from the central ejector pin protrusion area 5 on the other side of the long side 4.

[0105] (2) Flame retardant For the resin compositions listed in Tables 1 and 2, after drying at 140°C for 3 hours, injection molding was performed using a FANUC S-2000i100B injection molding machine at a cylinder temperature of 250°C and a mold temperature of 70°C. According to UL94, strip-shaped test pieces measuring 125 mm × 13 mm × 1 / 32 inch thick were prepared, and their flammability was evaluated. Compositions that met V-0 flammability were marked with ○, and those that did not were marked with ×. The results are shown in Tables 1 and 2.

[0106] [Table 1]

[0107] [Table 2]

[0108] As shown in Table 1, Examples 1 to 10, which contained PBT resin (A), PET resin (B), a transesterification inhibitor (C), and a flame retardant (D), and in which the amount of terminal hydroxyl groups of PBT resin (A) was 30 to 70 mmol / kg relative to the total amount of PBT resin (A) and PET resin (B), showed excellent results in both cooling time (release properties) and flammability evaluation. On the other hand, as shown in Table 2, Comparative Examples 2 to 6, in which the amount of terminal hydroxyl groups of PBT resin (A) was not within the range of 30 to 70 mmol / kg relative to the total amount of PBT resin (A) and PET resin (B), and / or did not contain the transesterification inhibitor (C), tended to have longer cooling times. Furthermore, Comparative Example 1, which did not contain the flame retardant (D), did not show flame retardancy. [Explanation of symbols]

[0109] 1 Molded product 2 Short side 3 cylinders 4 Long side 5. Eject pin protrusion area

Claims

1. A polyester resin composition comprising a polybutylene terephthalate resin, a recycled polyethylene terephthalate resin, a transesterification inhibitor, and a flame retardant, wherein the amount of terminal hydroxyl groups of the polybutylene terephthalate resin is 30 to 70 mmol / kg relative to the total amount of the polybutylene terephthalate resin and the recycled polyethylene terephthalate resin.

2. The polyester resin composition according to claim 1, wherein the sum of the amount of terminal hydroxyl groups in the polybutylene terephthalate resin and the recycled polyethylene terephthalate resin is 60 to 90 mmol / kg, relative to the total amount of the polybutylene terephthalate resin and the recycled polyethylene terephthalate resin.

3. The polyester resin composition according to claim 1 or 2, wherein the transesterification inhibitor comprises a phosphorus-based compound containing a sodium atom or a calcium atom.

4. The polyester resin composition according to claim 1 or 2, further comprising a crystal nucleating agent.

5. The polyester resin composition according to claim 1 or 2, further comprising 5 to 50% by mass of an inorganic filler based on the total amount of the polyester resin composition.

6. A resin molded article obtained using the polyester resin composition described in claim 1 or 2.

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