Resin composition, molded article, pellets, method for reducing burnt foreign matter in resin composition, and method for manufacturing resin composition

Abstract

The present invention provides a resin composition capable of providing molded articles with reduced burnt foreign matter, a method for reducing burnt foreign matter in molded articles, pellets, and resin compositions, and a method for manufacturing the resin composition. [Solution] The resin composition according to this disclosure contains 2.2 to 10 parts by mass of an epoxy compound having an internal epoxide in its molecule, with respect to 100 parts by mass of a thermoplastic polyester resin.

Description

[Technical Field]

[0001] The present invention relates to resin compositions, molded articles, pellets, a method for reducing burnt foreign matter in resin compositions, and a method for manufacturing resin compositions. In particular, this invention relates to resin compositions preferably used in transparent resin components of laser-welded bodies. [Background technology]

[0002] Thermoplastic polyester resins, including polybutylene terephthalate resin, are widely used in various equipment components due to their excellent mechanical strength, chemical resistance, and electrical insulation properties, as well as their superior heat resistance, moldability, and recyclability.

[0003] Recently, welding processes have been increasingly used to improve productivity, and among these, laser welding, which has minimal impact on electronic components, is being widely used. Laser welding is a technique in which a laser-transmitting resin component (hereinafter sometimes referred to as a "transmitting resin component") made of a laser-transmitting material and a laser-absorbing resin component (hereinafter sometimes referred to as an "absorbing resin component") made of a laser-absorbing material are placed on top of each other, and laser light is irradiated from the transparent resin component side to heat the interface with the absorbing resin component and weld them together. Resin compositions used in molded products for such applications are required to have the property (laser-weldability) that allows them to be welded by irradiation with laser light. Methods for manufacturing laser-welded bodies are described, for example, in Patent Documents 1 and 2. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2019-081365 [Patent Document 2] International Publication No. 2019 / 088058 [Overview of the project]

Problems to be Solved by the Invention

[0005] On the other hand, in order to improve the hydrolysis resistance of thermoplastic polyester resins, an epoxy compound is blended with the thermoplastic polyester resin. However, it has been found that when an epoxy compound is blended with a thermoplastic polyester resin and melt-kneaded in an extruder, or when a molded product obtained during molding causes burned foreign matters. In particular, when a large amount of epoxy compound is blended to improve the hydrolysis resistance of the thermoplastic polyester resin, or when it stays at a high temperature or for a long time in a molten state, it has been found that a serious problem of burned foreign matters is caused. An object of the present invention is to solve such problems, and to provide a resin composition capable of providing a molded product with reduced burned foreign matters, as well as a method for reducing burned foreign matters in a molded product, pellets, and a resin composition, and a method for producing a resin composition.

Means for Solving the Problems

[0006] Under such circumstances, as a result of the study by the present inventor, it has been found that the above problems can be solved by using an epoxy compound having an internal epoxide in the molecule as the epoxy compound. Specifically, the above problems have been solved by the following means. [1] Based on 100 parts by mass of a thermoplastic polyester resin, A resin composition containing 2.2 parts by mass or more and 10 parts by mass or less of an epoxy compound having an internal epoxide in the molecule. [2] The resin composition according to [1], wherein the resin composition is formed into a plate-shaped molded product having a thickness of 1.5 mm and a size of 60 mm square, and when the total value of the number of black spots visually confirmed from the test piece is measured three times using an infrared irradiation device, the total value is 9 or less. [3] The resin composition according to [1] or [2], further containing an amorphous resin. [4] The resin composition according to any one of [1] to [3], comprising 2.5 parts by mass or more and 10 parts by mass or less of an epoxy compound having an internal epoxide in its molecule, per 100 parts by mass of a thermoplastic polyester resin. [5] The resin composition according to any one of [1] to [4], wherein the content of epoxy compounds other than epoxy compounds having internal epoxides in the molecule is 0.5 parts by mass or less per 100 parts by mass of thermoplastic polyester resin. [6] The resin composition according to any one of [1] to [5], further comprising 1 to 60 parts by mass of amorphous resin per 100 parts by mass of thermoplastic polyester resin. [7] The resin composition according to any one of [1] to [6], further comprising 1 to 50 parts by mass of amorphous resin per 100 parts by mass of thermoplastic polyester resin. [8] The resin composition according to [3], wherein the amorphous resin comprises a polycarbonate resin. [9] The resin composition according to any one of [1] to [8], wherein the thermoplastic polyester resin comprises a polybutylene terephthalate resin.

[10] The resin composition according to any one of [1] to [9], wherein the epoxy compound having an internal epoxide in the molecule comprises an epoxidized natural oil.

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

[10] , wherein the epoxy compound having an internal epoxide in the molecule comprises linseed oil and / or soybean oil.

[12] A resin composition according to any one of [1] to

[11] , for forming a transparent resin member during laser welding.

[13] The resin composition according to any one of [1] to

[12] , wherein the epoxy compound having an internal epoxide in the molecule has a ratio of 0 to 10 moles of structure (B) per 100 moles of structure (A). [ka] (In structure (A), * indicates a connection site with another part.) [ka] (In structure (B), * indicates a connection site with another part.)

[14] The resin composition according to any one of [1] to

[13] , wherein the content of the epoxy compound having an internal epoxide in the molecule in the resin composition is 1.2 to 3.1% by mass, based on 100% by mass of the resin composition.

[15] The thermoplastic polyester resin comprises a polybutylene terephthalate resin, Furthermore, the mixture contains 1 to 60 parts by mass of amorphous resin per 100 parts by mass of thermoplastic polyester resin. The amorphous resin includes a polycarbonate resin. The epoxy compound having an internal epoxide within the molecule comprises linseed oil and / or soybean oil. A resin composition according to any one of [1] to

[14] , for forming a transparent resin member during laser welding.

[16] The resin composition is molded into a plate-shaped molded product with a thickness of 1.5 mm and a size of 60 mm square, and the number of black spots visible to the test piece is measured three times using an infrared irradiation device, and the total value is 9 or less. The epoxy compound having an internal epoxide within the molecule is included in an amount of 2.5 parts by mass or more and 10 parts by mass or less per 100 parts by mass of thermoplastic polyester resin. The content of epoxy compounds other than epoxy compounds having internal epoxides in the molecule is 0.5 parts by mass or less per 100 parts by mass of thermoplastic polyester resin. Furthermore, the mixture contains 1 to 50 parts by mass of amorphous resin per 100 parts by mass of thermoplastic polyester resin. The amorphous resin includes a polycarbonate resin. The thermoplastic polyester resin includes a polybutylene terephthalate resin, The epoxy compound having an internal epoxide within the molecule comprises linseed oil and / or soybean oil. It is for forming transparent resin components during laser welding. The epoxy compound having an internal epoxide within the molecule has a ratio of 0 to 10 moles of structure (B) to 100 moles of structure (A). The resin composition according to any one of [1] to

[15] , wherein the content of the epoxy compound having an internal epoxide in the molecule in the resin composition is 1.2 to 3.1% by mass, based on 100% by mass of the resin composition. [ka] (In structure (A), * indicates a connection site with another part.) [ka] (In structure (B), * indicates a connection site with another part.)

[17] A resin composition according to any one of [1] to

[16] , for molding in an injection molding machine equipped with a gate having a gate diameter of 0.5 mm or less, or an injection molding machine equipped with a hot runner. A molded article formed from any one of the resin compositions described in

[18] [1] to

[17] .

[19] A molded article according to

[18] , which is a transparent resin component of a laser-welded body. A pellet of the resin composition described in any one of

[20] [1] to

[17] . A molded product formed from the pellets described in

[21] and

[20] .

[22] A method for reducing burnt foreign matter in a resin composition containing 1.0 to 10 parts by mass of an epoxy compound per 100 parts by mass of a thermoplastic polyester resin, A reduction method comprising using an epoxy compound having an internal epoxide within the molecule as the epoxy compound.

[23] The reduction method according to

[22] , wherein the resin composition comprises 2.2 to 10 parts by mass of an epoxy compound having an internal epoxide in its molecule, per 100 parts by mass of a thermoplastic polyester resin.

[24] The reduction method according to

[22] or

[23] , further comprising 1 to 50 parts by mass of amorphous resin.

[25] A method for producing a resin composition, comprising blending an epoxy compound having an internal epoxide in its molecule with 100 parts by mass of a thermoplastic polyester resin in a ratio of 0.1 parts by mass to 10 parts by mass and extruding the mixture.

[26] A method for producing resin composition pellets according to

[25] , wherein the distance from the position where the epoxy compound is added to the tip of the screw is 11D or more, and the method comprises a liquid addition step.

[27] A method for producing pellets of the resin composition according to

[25] , wherein the resin composition is the resin composition according to any one of [1] to

[17] . [Effects of the Invention]

[0007] The present invention provides a resin composition capable of providing molded articles with reduced burnt foreign matter, as well as a method for reducing burnt foreign matter in molded articles, pellets, and resin compositions, and a method for manufacturing the resin composition. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram showing a test piece (transparent resin member I) for measuring the laser welding strength in the example. [Figure 2] This is a schematic diagram showing a test piece (absorbent resin member II) for measuring the laser welding strength in the example. [Figure 3] This is a schematic diagram showing a test specimen (a combination of a transparent resin member I and an absorbing resin member II) for measuring the laser welding strength of the example. [Figure 4] This is a schematic diagram showing the method for measuring the laser welding strength in the example. [Figure 5] This is a cross-sectional view showing an example of the screw configuration of an extruder used in the manufacturing method of the resin composition of this embodiment. [Modes for carrying out the invention]

[0009] The following describes in detail embodiments for carrying out the present invention (hereinafter simply referred to as "this embodiment"). Note that the following embodiment is illustrative for explaining the present invention, and the present invention is not limited to this embodiment. In this specification, "~" is used to mean that the numerical values ​​before and after it are included as the lower and upper limits. Furthermore, the upper and lower limits of the numerical values ​​in this specification are given as examples of this embodiment, regardless of the combination of upper and lower limits. In this specification, a preferred combination of embodiments is a more preferred embodiment. In this specification, all physical properties and characteristic values ​​shall be those at 23°C unless otherwise specified.

[0010] In this specification, unless otherwise specified, the weight-average molecular weight and number-average molecular weight are polystyrene equivalent values ​​measured by GPC (gel permeation chromatography) using a Tosoh HLC-8320GPC EcoSEC, tetrahydrofuran as the solvent, Shodex KF-G, KF-805L×3, and KF-800D columns, at a column temperature of 40°C and a flow rate of 1.2 mL / min, detected at a detection wavelength of 254 nm. If the measurement methods, etc., described in the standards shown in this specification differ from year to year, unless otherwise specified, the standards as of January 1, 2024 shall apply. If the measurement methods, etc., described in the standards shown in this specification have been discontinued as of January 1, 2024, the standards in effect at the time of discontinuation shall apply. Figures 1-4 may not accurately reflect reality due to their scales and other factors.

[0011] The resin composition of this embodiment is characterized by containing 2.2 to 10 parts by mass of an epoxy compound having an internal epoxide in its molecule, per 100 parts by mass of a thermoplastic polyester resin. By adopting this configuration, a resin composition is obtained that can provide molded products with reduced burning foreign matter.

[0012] By blending epoxy compounds with thermoplastic polyester resin, molded articles with excellent hydrolysis resistance can be obtained. However, it has been found that when epoxy compounds are blended, burnt foreign matter may occur in the resulting molded articles. The inventors investigated and found that burnt foreign matter tends to occur even during melt kneading. In this embodiment, it is presumed that the problem was solved by using an epoxy compound having an internal epoxide within the molecule as the epoxy compound. First, when the thermoplastic polyester resin and the epoxy compound are melt-kneaded, the epoxy groups of the epoxy compound react with the end groups of the thermoplastic polyester resin. On the other hand, epoxy compounds having epoxy groups at the ends are highly reactive, and if they react excessively with the end groups of the polyester resin, they thicken, adhering to and accumulating in the cylinder and screw inside the extruder, and it is presumed that this generates burnt foreign matter. In contrast, it was hypothesized that using an epoxy compound with an internal epoxide within the molecule suppressed the reaction with the end groups of the polyester resin compared to epoxy compounds with epoxy groups at the molecular ends, thus suppressing viscosity increase, and consequently suppressing adhesion and retention in the extruder, thereby effectively reducing burnt foreign matter.

[0013] The embodiments of the present invention will be described in detail below, but the description of the constituent elements described below is merely one example of an embodiment of the present invention and is not limited to these.

[0014] <Thermoplastic polyester resin> The resin composition in this embodiment includes a thermoplastic polyester resin. Thermoplastic polyester resin is a polyester obtained by polycondensation of dicarboxylic acid compounds and dihydroxy compounds, polycondensation of oxycarboxylic acid compounds, or polycondensation of these compounds, and may be either homopolyester or copolyester. The thermoplastic polyester resin used in this embodiment preferably contains a polyalkylene terephthalate resin, more preferably contains a polyethylene terephthalate resin and / or a polybutylene terephthalate resin, and even more preferably contains a polybutylene terephthalate resin. The thermoplastic polyester resin used in this embodiment is typically a crystalline resin.

[0015] As the dicarboxylic acid compound constituting the thermoplastic polyester resin, aromatic dicarboxylic acids or their ester-forming derivatives are preferably used. Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, biphenyl-2,2'-dicarboxylic acid, biphenyl-3,3'-dicarboxylic acid, biphenyl-4,4'-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, diphenylmethane-4,4'-dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic acid, diphenylisopropylidene-4,4'-dicarboxylic acid, 1,2-bis(phenoxy)ethane-4,4'-dicarboxylic acid, anthracene-2,5-dicarboxylic acid, anthracene-2,6-dicarboxylic acid, p-tert-phenylene-4,4'-dicarboxylic acid, pyridine-2,5-dicarboxylic acid, etc., with terephthalic acid being preferred.

[0016] These aromatic dicarboxylic acids may be used in combination of two or more types. As is well known, they can be used in polycondensation reactions not only as free acids but also as ester-forming derivatives such as dimethyl esters. Furthermore, in small amounts, these aromatic dicarboxylic acids can be used in combination with one or more aliphatic dicarboxylic acids such as adipic acid, azelaic acid, dodecanedionic acid, and sebacic acid, or alicyclic dicarboxylic acids such as 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid.

[0017] Examples of dihydroxy compounds constituting thermoplastic polyester resins include aliphatic diols such as ethylene glycol, propylene glycol, butanediol, hexylene glycol, neopentyl glycol, 2-methylpropane-1,3-diol, diethylene glycol, and triethylene glycol, as well as alicyclic diols such as cyclohexane-1,4-dimethanol, and mixtures thereof. In small amounts, one or more long-chain diols with molecular weights of 400 to 6,000, such as polyethylene glycol, poly-1,3-propylene glycol, and polytetramethylene glycol, may be copolymerized. In addition, aromatic diols such as hydroquinone, resorcinol, naphthalenediol, dihydroxydiphenyl ether, and 2,2-bis(4-hydroxyphenyl)propane can also be used.

[0018] In addition to the difunctional monomers mentioned above, small amounts of trifunctional monomers such as trimellitic acid, trimesic acid, pyromellitic acid, pentaerythritol, and trimethylolpropane can also be used to introduce branched structures, as well as monofunctional compounds such as fatty acids to adjust molecular weight. The thermoplastic polyester resin used is typically one that consists mainly of a polycondensation of a dicarboxylic acid and a diol, that is, one in which 50% by mass, preferably 70% by mass or more of the total thermoplastic polyester resin consists of this polycondensate. Aromatic carboxylic acids are preferred as the dicarboxylic acid, and aliphatic diols are preferred as the diol.

[0019] Of these, polyalkylene terephthalate resins are preferred, in which 95 mol% or more of the acid component is terephthalic acid and 95% by mass or more of the alcohol component is an aliphatic diol. Typical examples include polybutylene terephthalate resin and polyethylene terephthalate resin, with polybutylene terephthalate resin being preferred. These are preferably close to homopolyesters, that is, in which 95% by mass or more of the total resin consists of the terephthalic acid component and the 1,4-butanediol or ethylene glycol component.

[0020] Thermoplastic polyester resins are also preferably copolymerized with isophthalic acid, dimer acid, polyalkylene glycols such as polytetramethylene glycol (PTMG), and more preferably copolymerized with isophthalic acid. Examples of these copolymers include those with a copolymerization amount of 1 mol% or more and less than 50 mol% of the total segments of polyalkylene terephthalate, preferably less than 40 mol%, more preferably less than 30 mol%, and may be less than 20 mol%.

[0021] The thermoplastic polyester resin used in this embodiment may include recycled materials. Examples of recycled thermoplastic polyester resins include those obtained through material recycling, which involves crushing and washing molded product scraps, defective products, and collected used thermoplastic polyester resin molded products for reuse, as well as those obtained through chemical recycling (chemical decomposition). Furthermore, thermoplastic polyester resins derived from plant materials may also be used.

[0022] An example of the blend form of the thermoplastic polyester resin in this embodiment is that it contains at least polybutylene terephthalate resin. The mass ratio of polybutylene terephthalate resin in this blend form is preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 52% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and may also be 95% by mass or more, based on 100% by mass of the thermoplastic polyester resin. Setting it above the lower limit tends to result in a higher load deflection temperature of the resulting member and improved moldability of the resin composition. In the first embodiment, the mass ratio of polybutylene terephthalate resin may be 100% by mass of 100% by mass of the thermoplastic polyester resin contained in the resin composition, or, depending on the application, it may be 90% by mass or less, 70% by mass or less, or 60% by mass or less.

[0023] The polybutylene terephthalate resin used in this embodiment may be a homopolymer of polybutylene terephthalate, or a copolymer of a portion with isophthalic acid, dimer acid, polytetramethylene glycol (PTMG), or other polyalkylene glycols. Preferably, 1 to 30 mol% (preferably 5 to 25 mol%) of the terephthalic acid component in the polybutylene terephthalate resin may be isophthalic acid modified. Using such an isophthalic acid modified polybutylene terephthalate resin tends to improve toughness, fluidity, tracking resistance, and laser welding strength.

[0024] In the above blend configuration, polyethylene terephthalate resin is preferred as the resin other than polybutylene terephthalate resin. In the above blend form, it is particularly preferable that the blend contains 30% by mass or more (preferably 50% by mass or more) of polybutylene terephthalate resin in 100% by mass of thermoplastic polyester resin, and the total of polybutylene terephthalate resin and polyethylene terephthalate resin (the content of polyethylene terephthalate resin may be 0% by mass) accounts for 90% by mass or more (preferably 95% by mass or more) of 100% by mass of thermoplastic polyester resin. By incorporating polyethylene terephthalate resin, the warping of the resulting member tends to be suppressed more effectively.

[0025] The concentration of terminal carboxyl groups in the thermoplastic polyester resin is preferably 1 eq / ton or more, more preferably 7 eq / ton or more, preferably 23 eq / ton or less, and more preferably 22 eq / ton or less. This range tends to improve the fluidity of the resin composition. In this embodiment, if the resin composition contains two or more thermoplastic polyester resins, the concentration of terminal carboxyl groups in the thermoplastic polyester resins shall be the same as the concentration of terminal carboxyl groups in the mixture. The amount of terminal carboxyl groups can be determined by dissolving 0.5 g of thermoplastic polyester resin in 25 mL of benzyl alcohol and titrating with a 0.01 mol / L benzyl alcohol solution of sodium hydroxide.

[0026] The thermoplastic polyester resin used in this embodiment preferably has an intrinsic viscosity of 0.40 dL / g or higher, and more preferably 2.00 dL / g or lower. Setting the intrinsic viscosity below the upper limit tends to improve the moldability of the resulting component. Conversely, setting the intrinsic viscosity above the lower limit tends to improve mechanical properties such as tensile strength and flexural strength. The intrinsic viscosity of the thermoplastic polyester resin is preferably 0.50 dL / g or more, more preferably 0.65 dL / g or more, even more preferably 0.70 dL / g or more, and even more preferably 0.75 dL / g or more. The intrinsic viscosity is preferably 1.50 dL / g or less, and more preferably 1.00 dL / g or less.

[0027] The intrinsic viscosity of thermoplastic polyester resins is measured by the following method. Polybutylene terephthalate resin pellets are dissolved in a phenol / 1,1,2,2-tetrachloroethane (mass ratio 1 / 1) mixed solvent by stirring at 110°C for 1 hour to a concentration of 1.00 g / dL. The mixture is then cooled to 30°C. Using a fully automated solution viscometer, the drop time of the sample solution and the drop time of the solvent alone are measured at 30°C, and the intrinsic viscosity is calculated using the formula. Intrinsic viscosity=((1+4K H η sp ) 0.5 -1) / (2K H C) Here, η sp =η / η0-1, where η is the number of seconds for the sample solution to fall, η0 is the number of seconds for the solvent only to fall, C is the concentration of the sample solution (g / dL), and K is the concentration of the sample solution (g / dL). H K is Huggins' constant. H 0.33 was adopted. In this embodiment, if the resin composition contains two or more thermoplastic polyester resins, the intrinsic viscosity of the thermoplastic polyester resins shall be the intrinsic viscosity of the mixture.

[0028] The content of thermoplastic polyester resin (preferably polyalkylene terephthalate resin, more preferably polyethylene terephthalate resin and / or polybutylene terephthalate resin) in the resin composition of this embodiment is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, and may be 40% by mass or more, 45% by mass or more, or 50% by mass or more, depending on the application. Furthermore, the content of the thermoplastic polyester resin (preferably polyalkylene terephthalate resin, more preferably polyethylene terephthalate resin and / or polybutylene terephthalate resin) is preferably 80% by mass or less, more preferably 75% by mass or less, even more preferably 70% by mass or less, and may be 65% by mass or less, 60% by mass or less, or 55% by mass or less, depending on the application. The resin composition of this embodiment may contain only one type of thermoplastic polyester resin (preferably polyalkylene terephthalate resin, more preferably polybutylene terephthalate resin and / or polybutylene terephthalate resin), or it may contain two or more types. When two or more types are included, it is preferable that the total amount is within the above range.

[0029] <Amorphous resin> The resin composition of this embodiment may also contain amorphous resin. By including amorphous resin, the amount of polyester resin can be relatively reduced, suppressing burnt foreign matter and achieving high laser transmittance. Furthermore, warping of the resulting molded product can be effectively suppressed. While there are no specific requirements regarding the type of amorphous resin, it is usually an amorphous thermoplastic resin, with examples including styrene resins, polycarbonate resins, acrylic resins, and modified polyphenylene ether resins. It is preferable that the resin contains styrene resin and / or polycarbonate resin, and more preferably polycarbonate resin.

[0030] The amorphous resin used in this embodiment may be a virgin amorphous resin or a recycled amorphous resin. The amorphous resin is usually an amorphous thermoplastic resin. Examples of recycled amorphous resins include those obtained through material recycling, where used amorphous resin molded products are crushed, washed, and reused, and those obtained through chemical recycling (chemical decomposition). Amorphous resins derived from plant materials may also be used.

[0031] <<Styrene-based resin>> The styrene-based resin used in this embodiment includes homopolymers of styrene-based monomers, copolymers of styrene-based monomers and monomers copolymerizable with styrene-based monomers, and the like. In copolymers of styrene-based monomers and copolymerizable monomers, it is preferable that 50% by mass or more of the total monomer is styrene-based monomer, more preferably 60% by mass or more is styrene-based monomer, and preferably 100% by mass or less is styrene-based monomer.

[0032] Styrene monomers refer to styrene and styrene having substituents, and include styrene, α-methylstyrene, p-methylstyrene, vinylxylene, ethylstyrene, dimethylstyrene, p-tert-butylstyrene, vinylnaphthalene, methoxystyrene, monobromstyrene, dibromstyrene, fluorostyrene, and tribromstyrene, with styrene and α-methylstyrene being more preferred, and styrene being particularly preferred. Furthermore, among the monomers that make up styrene-based resins, monomers other than styrene-based monomers include (meth)acrylic acid ester monomers, maleimide monomers such as maleimide, N-methylmaleimide, and N-phenylmaleimide, α,β-unsaturated carboxylic acids and their anhydrides such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, phthalic acid, and itaconic acid, and rubbers such as butadiene.

[0033] The polystyrene resin used in this embodiment may include rubber-reinforced polystyrene resin. Specific examples of rubber-reinforced polystyrene resins include acrylonitrile-styrene copolymer (AS resin), high-impact polystyrene resin (HIPS), acrylonitrile-butadiene-styrene copolymer (ABS resin), acrylonitrile-acrylic rubber-styrene copolymer (AAS resin), acrylonitrile-styrene-acrylic rubber copolymer (ASA resin), acrylonitrile-ethylene propylene-rubber-styrene copolymer (AES resin), styrene-IPN type rubber copolymer, and other resins.

[0034] In this embodiment, it is also preferable that a portion of the polystyrene resin used is a styrene-maleic acid polymer (preferably a styrene-maleic anhydride polymer). The styrene-maleic acid polymer acts as a compatibilizer between the polybutylene terephthalate resin and the polystyrene resin and / or rubber-reinforced polystyrene resin. As a result, the strength of the resulting component can be increased.

[0035] In this embodiment, the polystyrene resin preferably includes at least one selected from polystyrene resin (GPPS), acrylonitrile-styrene copolymer (AS resin), high-impact polystyrene resin (HIPS), acrylonitrile-butadiene-styrene copolymer (ABS resin), acrylonitrile-acrylic rubber-styrene copolymer (AAS resin), acrylonitrile-styrene-acrylic rubber copolymer (ASA resin), and acrylonitrile-ethylene propylene rubber-styrene copolymer (AES resin), and more preferably high-impact polystyrene resin (HIPS). Furthermore, from the viewpoint of heat resistance, polystyrene resin (GPPS) and acrylonitrile-styrene copolymer (AS resin) are more preferred, and AS resin is even more preferred.

[0036] <<Polycarbonate resin>> The polycarbonate resin used in this embodiment is a branched thermoplastic polymer or copolymer obtained by reacting a dihydroxy compound or a small amount thereof with a polyhydroxy compound with phosgene or a diester carbonate.

[0037] The dihydroxy compounds used as raw materials are substantially free of bromine atoms, and aromatic dihydroxy compounds are preferred. Specifically, examples include 2,2-bis(4-hydroxyphenyl)propane (i.e., bisphenol A), tetramethylbisphenol A, bis(4-hydroxyphenyl)-p-diisopropylbenzene, hydroquinone, resorcinol, 4,4-dihydroxydiphenyl, etc., with bisphenol A being preferred. In addition, compounds in which one or more tetraalkylphosphonium sulfonates are bonded to the above aromatic dihydroxy compounds can also be used.

[0038] As the polycarbonate resin, among those described above, an aromatic polycarbonate resin derived from 2,2-bis(4-hydroxyphenyl)propane, or an aromatic polycarbonate copolymer derived from 2,2-bis(4-hydroxyphenyl)propane and another aromatic dihydroxy compound is preferable. Further, a copolymer mainly composed of an aromatic polycarbonate resin, such as a copolymer with a polymer or oligomer having a siloxane structure, may be used. Furthermore, two or more of the above-described polycarbonate resins may be mixed and used.

[0039] To adjust the molecular weight of the polycarbonate resin, a monohydric aromatic hydroxy compound may be used. For example, m- and p-methylphenol, m- and p-propylphenol, p-tert-butylphenol, p-long-chain alkyl-substituted phenol, and the like can be mentioned.

[0040] The viscosity average molecular weight (Mv) of the polycarbonate resin is preferably 10,000 or more, more preferably 12,000 or more, further preferably 13,000 or more, and particularly preferably more than 14,000. When a polycarbonate resin having a viscosity average molecular weight lower than 10,000 is used, the resulting resin composition tends to have low mechanical strength such as impact resistance. Also, Mv is preferably 60,000 or less, more preferably 40,000 or less, further preferably 35,000 or less, still more preferably 30,000 or less, and may be 25,000 or less, 20,000 or less. When it is higher than 60,000, the fluidity of the resin composition may deteriorate and the moldability may worsen.

[0041] In the present invention, the viscosity average molecular weight (Mv) of the polycarbonate resin is a value calculated from the following Schnell viscosity formula by measuring the viscosity of a methylene chloride solution of the polycarbonate resin at 25 °C using an Ubbelohde viscometer to obtain the intrinsic viscosity ([η]). [η]=1.23×10 -4 Mv 0.83

[0042] The melt flow rate (MFR) of polycarbonate resin, measured in accordance with JIS K7210 (temperature 300°C, load 1.20 kgf), is preferably 3 g / 10 min or more, more preferably 6 g / 10 min or more, preferably 100 g / 10 min or less, and more preferably 70 g / 10 min or less. When the MFR is within the above range, the effects of the present invention tend to be exhibited more effectively. The melt volume rate (MVR) of polycarbonate resin, measured according to JIS K7210 (temperature 300°C, load 1.20 kgf), is 0.5 to 80 cm³. 3 It is preferable that the g / 10 mins be 40-70 cm 3 A value of 10 minutes is more preferable. When the MVR is within the above range, the effects of the present invention tend to be exhibited more effectively.

[0043] The method for producing the polycarbonate resin is not particularly limited, and polycarbonate resin produced by either the phosgene method (interfacial polymerization method) or the melting method (transesterification method) can be used. Furthermore, polycarbonate resin produced by the melting method and then subjected to post-treatment to adjust the amount of terminal OH groups is also preferred.

[0044] In this embodiment, the amorphous resin content in the resin composition is preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 7 parts by mass or more, even more preferably 10 parts by mass or more, even more preferably 15 parts by mass or more, even more preferably 20 parts by mass or more, and for example, 60 parts by mass or less, preferably 50 parts by mass or less, more preferably 40 parts by mass or less, even more preferably 35 parts by mass or less, and even more preferably 30 parts by mass or less. Setting the content above the lower limit tends to further improve the low warpage and laser transmittance of the resulting molded product. Setting the content below the upper limit tends to further improve the heat resistance and basic physical properties of the resin composition or molded product. The resin composition in this embodiment may contain only one type of amorphous resin, or it may contain two or more types. When it contains two or more types, it is preferable that the total amount is within the above range.

[0045] In this embodiment, the total content of thermoplastic polyester resin and amorphous resin in the resin composition is preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 55% by mass or more, even more preferably 60% by mass or more, and also preferably 90% by mass or less, more preferably 80% by mass or less, even more preferably 75% by mass or less, and even more preferably 70% by mass or less.

[0046] <Epoxy compounds containing internal epoxides within the molecule> The resin composition of this embodiment contains an epoxy compound having an internal epoxide within its molecule (internal epoxide-containing epoxy compound). By including an epoxy compound having an internal epoxide within the molecule, such as the compound main chain, the heat and moisture resistance of the resulting molded product is improved, and burnt foreign matter is reduced. An epoxy compound containing an internal epoxide is a compound having structure (A). [ka] In structure (A), * indicates a connection site with another part. A specific example of an epoxy compound containing an internal epoxide is the compound represented by formula (A-1). [ka] In the above structure (A-1), R 1 and R 2 At least one of them is an alkyl group, a cycloalkyl group, an alkenyl group or an aryl group, R 3 and R 4 At least one of them is an alkyl group, a cycloalkyl group, an alkenyl group, or an aryl group. 1 , R 2 , R3 and R 4 Each group in may have substituents, and the substituents may have further substituents.

[0047] Examples of the substituents mentioned above are preferably halogen atoms, cyano groups, nitro groups, hydroxyl groups, alkyl groups, alkoxy groups, aryl groups, aryloxy groups, heterocyclic groups, heterocyclic oxy groups, alkenyl groups, alkylsulfanyl groups, arylsulfanyl groups, acyl groups, or amino groups; more preferably halogen atoms, alkyl groups, alkoxy groups, aryl groups, aryloxy groups, alkenyl groups, or acyl groups; even more preferably alkyl groups, aryl groups, aryloxy groups, or alkenyl groups; and even more preferably alkyl groups. The formula weight of these substituents is preferably 15 or more, and preferably 200 or less. For example, the formula weight of a methyl group (-CH3) is 15.

[0048] The molecular weight of the compound represented by formula (A-1) is preferably 50 or more, more preferably 70 or more, preferably 5000 or less, and more preferably 1000 or less. Setting it above the lower limit tends to suppress bleed-out of the epoxy compound and further improve the basic physical properties. Setting it below the upper limit tends to improve compatibility with thermoplastic polyester resins and further improve the basic physical properties of the resulting molded article. If the compound represented by formula (A-1) is a mixture, the molecular weight shall be the weighted average value.

[0049] Conventionally, epoxy compounds incorporated into thermoplastic resins were generally compounds having structure (B) (hereinafter referred to as "terminated epoxides"). [ka] In structure (B), * indicates a connection site with another part. An example of a compound having structure (B) is the compound represented by formula (B-1). [ka] In formula (B), R 1x and R 2x Both are hydrogen atoms, or R 3x and R 4x Both are hydrogen, or R 1x ~R 4x At least three of them are hydrogen atoms. 1x ~R 4x Of these, the groups other than the hydrogen atom are substituents, and examples of substituents are those described in the section on formula (A-1) above. Furthermore, it goes without saying that compounds having structure (B) also include compounds whose side chains contain structure (B), such as cresol novolac type epoxy resins.

[0050] In the case of compounds having structure (A), the epoxy group is located inside the molecule, such as in the main chain, rather than at the terminal position, which makes the reaction less likely to proceed, and as a result, the amount of burnt foreign matter is reduced. In contrast, in the case of compounds with structure (B), the epoxy group is located at the terminal position, so the reaction proceeds easily, and burnt foreign matter is more likely to be generated compared to compounds with structure (A).

[0051] In this embodiment, the internal epoxide-containing epoxy compound is, for example, an epoxy compound that contains more of structure (A) than structure (B), and does not exclude the presence of structure (B). In this embodiment, the internal epoxide-containing epoxy compound preferably has a proportion of structure (B) of 10 moles or less, more preferably 5 moles or less, even more preferably 1 mole or less, or even 0 moles, per 100 moles of structure (A).

[0052] The internal epoxide-containing epoxy compound used in this embodiment is preferably an epoxidized fatty acid ester. Epoxylated fatty acid esters are compounds in which fatty acid esters have been epoxidized. As fatty acid esters, fatty acid esters having one or more (preferably 2 to 10) unsaturated bonds inside the molecule are preferred. Furthermore, it is preferable that the epoxidized fatty acid ester is an epoxidized natural oil. As the epoxidized natural oils, epoxidized animal oils and / or epoxidized vegetable oils are preferred, and epoxidized vegetable oils are more preferred. Examples of animal fats include beef tallow, pork tallow, chicken tallow, milk tallow, and fish oil. The vegetable oil is not particularly limited as long as it mainly consists of triglycerides containing unsaturated fatty acids as fatty acid components. Examples include soybean oil, rapeseed oil, linseed oil, corn oil, palm oil, sunflower oil, grape oil, cottonseed oil, sesame oil, rice bran oil, peanut oil, castor oil, tung oil, safflower oil, olive oil, and grapeseed oil. At least one selected from the group consisting of soybean oil, rapeseed oil, linseed oil, corn oil, and palm oil is preferred, linseed oil and / or soybean oil is more preferred, and linseed oil is even more preferred.

[0053] The epoxy equivalent of the internally epoxide-containing epoxy compound (preferably an epoxidized fatty acid ester, or preferably an epoxidized natural oil) is preferably 1500 g / eq or less, more preferably 1000 g / eq or less, even more preferably 800 g / eq or less, even more preferably 500 g / eq or less, even more preferably 300 g / eq or less, and also preferably 50 g / eq or more, more preferably 75 g / eq or more, even more preferably 100 g / eq or more, and even more preferably 150 g / eq or more. Setting it below the upper limit tends to improve hydrolysis resistance. Setting it above the lower limit tends to suppress thickening of the resin composition. If the resin composition of this embodiment contains two or more internal epoxide-containing epoxy compounds, the epoxy equivalent is the weighted average value of the epoxy equivalents of the internal epoxide-containing epoxy compounds.

[0054] The proportion of oxirane oxygen in the internal epoxide-containing epoxy compound is preferably 4.0% by mass or more, more preferably 5.0% by mass or more, even more preferably 6.0% by mass or more, even more preferably 6.5% by mass or more, even more preferably 7.0% by mass or more, even more preferably 7.5% by mass or more, and also preferably 12.0% by mass or less, and more preferably 10.0% by mass or less.

[0055] For further details regarding the internal epoxide-containing epoxy compound, please refer to paragraphs 0046 to 0070 of Japanese Patent Publication No. 2019-026727 and paragraphs 0016 to 0025 of Japanese Patent Publication No. 2023-136871, in addition to the above, and this information is incorporated herein by reference. Commercially available epoxy compounds containing internal epoxides can also be used, for example, Sanwa Synthetic Chemical Co., Ltd.'s Chemisizer SE-100 (epoxide soybean oil, ESBO, general-purpose grade), Chemisizer SE-100ST (epoxide soybean oil, high-grade), Chemisizer ELS-100 (epoxide linseed oil), and Shin Nippon Rikagaku Co., Ltd.'s Sansosizer E-2000H (epoxide soybean oil), Sansosizer E-9000H (epoxide linseed oil). Examples include linseed oil, Sanso-sizer E-4030 (epoxidized fatty acid isobutyl), Sanso-sizer E-6000 (epoxidized fatty acid 2-ethylhexyl), ADEKA's ADEKA-sizer O-130P (epoxidized soybean oil), ADEKA-sizer O-180A (epoxidized linseed oil), ADEKA-sizer D-32 (epoxidized fatty acid octyl ester), ADEKA-sizer D-55 (epoxidized fatty acid alkyl ester), etc.

[0056] The content of the internal epoxide-containing epoxy compound in the resin composition of this embodiment is, for example, 1.0 part by mass or more, preferably 1.5 parts by mass or more, more preferably 2.2 parts by mass or more, even more preferably 2.5 parts by mass or more, and depending on the application, even more preferably 3.0 parts by mass or more, and also 10 parts by mass or less, preferably 8 parts by mass or less, more preferably 7 parts by mass or less, even more preferably 6 parts by mass or less, and depending on the application, it may be 4.5 parts by mass or less. Setting the content above the lower limit tends to further improve the moisture and heat resistance and tensile strain of the molded product. Setting the content below the upper limit tends to further improve the suppression of discoloration of the molded product, the effect of suppressing bleed-out after heating, and the rigidity.

[0057] The content of the internal epoxide-containing epoxy compound in the resin composition of this embodiment is preferably 1.2% by mass or more, more preferably 1.3% by mass or more, preferably 3.1% by mass or less, more preferably 3.0% by mass or less, and even more preferably 2.5% by mass or less, based on 100% by mass of the resin composition. By keeping it below the above upper limit, the productivity of the resin composition tends to improve further. The resin composition of this embodiment may contain only one internal epoxide-containing epoxy compound, or it may contain two or more. When it contains two or more, it is preferable that the total amount is within the above range.

[0058] The resin composition of this embodiment may or may not contain epoxy compounds other than epoxy compounds having internal epoxides in their molecules. The resin composition of this embodiment preferably contains substantially no epoxy compounds other than epoxy compounds having internal epoxides in the molecule. For example, the content of epoxy compounds other than epoxy compounds having internal epoxides in the molecule is preferably 0.5 parts by mass or less, more preferably 0.3 parts by mass or less, even more preferably 0.1 parts by mass or less, and even more preferably 0.01 parts by mass or less, per 100 parts by mass of thermoplastic polyester resin.

[0059] <Stabilizer> The resin composition in this embodiment may contain stabilizers (light stabilizers and / or heat stabilizers). The stabilizer preferably contains one or more compounds selected from the group consisting of thioether compounds, phosphorus compounds, hindered phenol compounds, and phosphite compounds, with phosphorus compounds and / or hindered phenol compounds being more preferred. Furthermore, in this embodiment, it is also preferable to use two or more thioether compounds, hindered phenol compounds, and phosphite compounds in combination as needed.

[0060] As the thioether compound, any conventionally known sulfur atom-containing compound can be used, with thioethers being particularly preferred. The resin composition of this embodiment tends to have a good appearance and improved thermal stability when it contains a thioether compound. Specifically, examples include didodecylthiodipropionate, ditetradecylthiodipropionate, dioctadecylthiodipropionate, pentaerythritol tetrakis(3-dodecylthiopropionate), 2,2-bis{[3-(dodecylthio)-1-oxopropoxy]methyl}propane-1,3-diylbis[3-(dodecylthio)propionate], thiobis(N-phenyl-β-naphthylamine), 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, tetramethylthiuram monosulfide, tetramethylthiuram disulfide, nickel dibutyldithiocarbamate, nickel isopropylxanthate, and trilauryl trithiophosphite. Among these, 2,2-bis{[3-(dodecylthio)-1-oxopropoxy]methyl}propane-1,3-diylbis[3-(dodecylthio)propionate] is preferred. Commercially available products include "C-NOX 412S" manufactured by Cipro Chemical Co., Ltd. and "ADEKA AO-412S" manufactured by ADEKA Corporation.

[0061] Examples of phosphorus-based stabilizers include phosphorous acid, phosphoric acid, phosphorous acid esters (phosphites), trivalent phosphate esters (phosphonites), and pentavalent phosphate esters (phosphates), with organic phosphite compounds, organic phosphonite compounds, and organic phosphate compounds being preferred.

[0062] Preferably, the organic phosphate compound is of the following formula: (R 1 O) 3-n P(=O)OH n (In the formula, R 1 (where n is an alkyl group or an aryl group, which may be the same or different; n is an integer between 0 and 2.) It is a compound represented by . More preferably, R1 Examples include long-chain alkyl acid phosphate compounds having 8 to 30 carbon atoms. Specific examples of alkyl groups having 8 to 30 carbon atoms include octyl group, 2-ethylhexyl group, isooctyl group, nonyl group, isononyl group, decyl group, isodecyl group, dodecyl group, tridecyl group, isotridecyl group, tetradecyl group, hexadecyl group, octadecyl group, eicosyl group, and triacontyl group.

[0063] Examples of long-chain alkyl acid phosphates include octyl acid phosphate, 2-ethylhexyl acid phosphate, decyl acid phosphate, lauryl acid phosphate, octadecyl acid phosphate, oleyl acid phosphate, behenyl acid phosphate, phenyl acid phosphate, nonylphenyl acid phosphate, cyclohexyl acid phosphate, phenoxyethyl acid phosphate, and alkoxypolyethylene glycol acid phosphate. Examples include octadecyl acid phosphate, bisphenol A acid phosphate, dimethyl acid phosphate, diethyl acid phosphate, dipropyl acid phosphate, diisopropyl acid phosphate, dibutyl acid phosphate, dioctyl acid phosphate, di-2-ethylhexyl acid phosphate, dioctyl acid phosphate, dilauryl acid phosphate, distearyl acid phosphate, diphenyl acid phosphate, and bisnonylphenyl acid phosphate. Among these, octadecyl acid phosphate is preferred, and this is commercially available under the trade name "ADEKA Stab AX-71" from ADEKA Corporation.

[0064] Preferably, the organophosphite compound is of the following formula: R 2 OP(OR 3 )(OR 4 ) (In the formula, R 2 , R 3 and R 4 These are a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, or an aryl group having 6 to 30 carbon atoms, respectively.2 , R 3 and R 4 At least one of them is an aryl group with 6 to 30 carbon atoms. Examples of compounds represented by [the formula shown] are given.

[0065] Examples of organic phosphite compounds include triphenyl phosphite, tris(nonylphenyl) phosphite, dilauryl hydrogen phosphite, triethyl phosphite, tridecyl phosphite, tris(2-ethylhexyl) phosphite, tris(tridecyl) phosphite, tristearyl phosphite, diphenyl monodecyl phosphite, monophenyl didecyl phosphite, diphenyl mono(tridecyl) phosphite, tetraphenyldipropylene glycol diphosphite, tetraphenyltetra(tridecyl)pentaerythritol tetraphosphite, hydrogenated bisphenol A phenol phosphite polymer, diphenyl hydrogen phosphite, 4,4'-butylidene-bis(3-methyl-6-tert-butylphenyl di(tridecyl) phosphite), and tetra(tridecyl)4,4'-iso Examples include propyridene diphenyl diphosphite, bis(tridecyl)pentaerythritol diphosphite, bis(nonylphenyl)pentaerythritol diphosphite, dilauryl pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, tris(4-tert-butylphenyl) phosphite, tris(2,4-di-tert-butylphenyl) phosphite, hydrogenated bisphenol A pentaerythritol phosphite polymer, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,2'-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite, and bis(2,4-dicumylphenyl)pentaerythritol diphosphite. Among these, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite is preferred.

[0066] The organic phosphonite compound is preferably one of the following formulas: R 5 -P(OR 6 )(OR 7 ) (In the formula, R 5 , R 6 and R 7 These are a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, or an aryl group having 6 to 30 carbon atoms, respectively. 5 , R 6 and R 7 At least one of them is an aryl group with 6 to 30 carbon atoms. Examples of compounds represented by [the formula shown] are given.

[0067] Examples of organic phosphonite compounds include tetrakis(2,4-di-iso-propylphenyl)-4,4'-biphenylenediphosphonite, tetrakis(2,4-di-n-butylphenyl)-4,4'-biphenylenediphosphonite, tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylenediphosphonite, tetrakis(2,4-di-tert-butylphenyl)-4,3'-biphenylenediphosphonite, and tetrakis(2,4-di-tert-butylphenyl)-3,3'-biphenylenediphosphona Examples include tetrakis(2,6-di-iso-propylphenyl)-4,4'-biphenylenediphosphonite, tetrakis(2,6-di-n-butylphenyl)-4,4'-biphenylenediphosphonite, tetrakis(2,6-di-tert-butylphenyl)-4,4'-biphenylenediphosphonite, tetrakis(2,6-di-tert-butylphenyl)-4,3'-biphenylenediphosphonite, and tetrakis(2,6-di-tert-butylphenyl)-3,3'-biphenylenediphosphonite.

[0068] Examples of hindered phenol compounds include pentaerythritol tetrakis(3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate), octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, thiodiethylenebis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), pentaerythritol tetrakis(3-(3,5-di-neopentyl-4-hydroxyphenyl)propionate), and 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene. Among these, pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) and octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate are preferred. Commercially available options include ADEKA products such as "ADEKA Stub AO-60" and "ADEKA Stub AO-330," and BASF products such as "Irganox Knox 1010."

[0069] Preferably, the phosphite compound is of the formula: R 2 OP(OR 3 )(OR 4 ) (In the formula, R 2 , R 3 and R 4 These are a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, or an aryl group having 6 to 30 carbon atoms, respectively. 2 , R 3 and R 4 At least one of them is an aryl group with 6 to 30 carbon atoms. Examples of compounds represented by [the formula shown] are given.

[0070] Phosphite compounds include, for example, triphenyl phosphite, tris(nonylphenyl) phosphite, dilauryl hydrogen phosphite, triethyl phosphite, tridecyl phosphite, tris(2-ethylhexyl) phosphite, tris(tridecyl) phosphite, tristearyl phosphite, diphenyl monodecyl phosphite, monophenyl didecyl phosphite, diphenyl mono(tridecyl) phosphite, tetraphenyldipropylene glycol diphosphite, tetraphenyltetra(tridecyl)pentaerythritol tetraphosphite, hydrogenated bisphenol A phenol phosphite polymer, diphenyl hydrogen phosphite, 4,4'-butylidene-bis(3-methyl-6-tert-butylphenyl di(tridecyl) phosphite, tetra(tridecyl)4,4'-isopropyl Examples include lopyridene diphenyl diphosphite, bis(tridecyl)pentaerythritol diphosphite, bis(nonylphenyl)pentaerythritol diphosphite, dilauryl pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, tris(4-tert-butylphenyl) phosphite, tris(2,4-di-tert-butylphenyl) phosphite, hydrogenated bisphenol A pentaerythritol phosphite polymer, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, 2,2'-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite, and bis(2,4-dicumylphenyl)pentaerythritol diphosphite. Among these, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite is preferred. A commercially available example is "ADEKA Stab PEP-36" manufactured by ADEKA Corporation.

[0071] In addition, as stabilizers, specific examples can be found in paragraphs 0067-0075 of Japanese Patent Publication No. 2021-063196, paragraphs 0046-0057 of Japanese Patent Publication No. 2018-070722, paragraphs 0030-0037 of Japanese Patent Publication No. 2019-056035, and paragraphs 0066-0078 of International Publication No. 2017 / 038949, the contents of which are incorporated herein by reference.

[0072] The stabilizer content in the resin composition is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and even more preferably 0.3 parts by mass or more, based on 100 parts by mass of the total of the thermoplastic polyester resin and amorphous resin. Setting the content above the lower limit tends to further improve the suppression of thermal degradation and oxidative degradation of the resin during melt mixing, molding, and use of the molded product, and tends to improve heat resistance. Furthermore, the upper limit of the stabilizer content is preferably 1.5 parts by mass or less, more preferably 1.0 part by mass or less, and even more preferably 0.8 parts by mass or less, based on 100 parts by mass of the total of the thermoplastic polyester resin and amorphous resin. Setting the content below the upper limit tends to effectively suppress adverse effects on appearance and physical properties due to aggregation of additives such as stabilizers, and tends to suppress discoloration of the resin composition. The resin composition of this embodiment may contain only one stabilizer or two or more stabilizers. When two or more stabilizers are included, it is preferable that the total amount is within the above range.

[0073] <Release agent> The resin composition of this embodiment preferably contains a mold release agent. A wide range of known release agents can be used, such as aliphatic carboxylic acid amides, aliphatic carboxylic acids, esters of aliphatic carboxylic acids and alcohols, aliphatic hydrocarbon compounds with a number average molecular weight of 200 to 15000, and polysiloxane-based silicone oils.

[0074] Examples of aliphatic carboxylic acid amides include compounds obtained by the dehydration reaction of a higher aliphatic monocarboxylic acid and / or polybasic acid with a diamine. Preferred higher aliphatic monocarboxylic acids include saturated aliphatic monocarboxylic acids and hydroxycarboxylic acids having 16 or more carbon atoms, such as palmitic acid, stearic acid, behenic acid, montanic acid, and 12-hydroxystearic acid. Examples of polybasic acids include aliphatic dicarboxylic acids such as malonic acid, succinic acid, adipic acid, sebacic acid, pimelic acid, and azelaic acid; aromatic dicarboxylic acids such as phthalic acid and terephthalic acid; and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid and cyclohexylsuccinic acid. Examples of diamines include ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, hexamethylenediamine, metaxylylenediamine, tolylenediamine, paraxylylenediamine, phenylenediamine, and isophoronediamine. As carboxylic acid amide compounds, compounds obtained by polycondensation of stearic acid, sebacic acid, and ethylenediamine are preferred, and compounds obtained by polycondensation of 2 moles of stearic acid, 1 mole of sebacic acid, and 2 moles of ethylenediamine are even more preferred. In addition to bisamide compounds obtained by reacting diamines with aliphatic carboxylic acids, such as N,N'-methylenebisstearate and N,N'-ethylenebisstearate, dicarboxylic acid amide compounds such as N,N'-dioctadecylterephthalamide can also be suitably used.

[0075] Examples of aliphatic carboxylic acids include saturated or unsaturated aliphatic monovalent, divalent, or trivalent carboxylic acids. Here, aliphatic carboxylic acids also include alicyclic carboxylic acids. Among these, preferred aliphatic carboxylic acids are monovalent or divalent carboxylic acids having 6 to 36 carbon atoms, and more preferably aliphatic saturated monovalent carboxylic acids having 6 to 36 carbon atoms. Specific examples of such aliphatic carboxylic acids include palmitic acid, stearic acid, caproic acid, capric acid, lauric acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, melissic acid, tetrariacontanoic acid, montanic acid, adipic acid, and azelaic acid.

[0076] As the aliphatic carboxylic acid in the ester of an aliphatic carboxylic acid and an alcohol, for example, the same aliphatic carboxylic acid as the aliphatic carboxylic acid can be used. On the other hand, as the alcohol, for example, saturated or unsaturated monohydric or polyhydric alcohols can be used. These alcohols may have substituents such as fluorine atoms or aryl groups. Among these, monohydric or polyhydric saturated alcohols having 30 or fewer carbon atoms are preferred, and aliphatic or alicyclic saturated monohydric alcohols or aliphatic saturated polyhydric alcohols having 30 or fewer carbon atoms are more preferred. Specific examples of such alcohols include octanol, decanol, dodecanol, stearyl alcohol, behenyl alcohol, ethylene glycol, diethylene glycol, glycerin, pentaerythritol, 2,2-dihydroxyperfluoropropanol, neopentylene glycol, ditrimethylolpropane, and dipentaerythritol. Specific examples of esters of aliphatic carboxylic acids and alcohols include beeswax (a mixture mainly composed of myricyl palmitate), stearyl stearate, behenyl behenate, stearyl behenate, glycerin monopalmitate, glycerin monostearate, glycerin distearate, glycerin tristearate, pentaerythritol monopalmitate, pentaerythritol monostearate, pentaerythritol distearate, pentaerythritol tristearate, pentaerythritol tetrastearate, and esters of montanic acid and polyfunctional alcohols.

[0077] Examples of aliphatic hydrocarbons with a number-average molecular weight of 200 to 15000 include liquid paraffin, paraffin wax, microwax, polyethylene wax, Fischer-Tropsch wax, and α-olefin oligomers having 3 to 12 carbon atoms. Note that alicyclic hydrocarbons are also included as aliphatic hydrocarbons. Furthermore, the number-average molecular weight of the aliphatic hydrocarbons is preferably 5000 or less.

[0078] Examples of polyolefin waxes include polyethylene wax, polypropylene wax, and polyethylene propylene wax, with polyethylene wax being preferred. Polyolefin wax may be unmodified or modified. Examples of modified polyolefin waxes include vinyl ester-modified polyolefin wax, acid-modified polyolefin wax, and oxidized polyolefin wax, with oxidized polyolefin wax being preferred. Oxidized polyolefin wax has excellent compatibility with thermoplastic resins and tends to effectively suppress mold deposits in the resulting resin composition.

[0079] Oxidized polyolefin waxes can be obtained by oxidizing the corresponding unmodified polyolefin wax. Examples of oxidized polyethylene waxes include Licowax® PED521, PED522, PED121, and Ceridust® 3715, all manufactured by Clariant Chemicals. In addition to the above, commercially available polyolefin waxes can also be referenced to the description in paragraph 0028 of Japanese Patent Publication No. 2022-140470, which is incorporated herein by reference.

[0080] The weight-average molecular weight of the polyolefin wax is preferably 800 or more, more preferably 1,000 or more, even more preferably 1,500 or more, even more preferably 2,000 or more, and even more preferably 2,500 or more. Setting it above the lower limit tends to further shorten the growing time. Furthermore, the weight-average molecular weight of the polyolefin wax is preferably 30,000 or less, more preferably 20,000 or less, even more preferably 15,000 or less, and even more preferably 10,000 or less. Setting it below the upper limit tends to further improve the fluidity of the resin composition during molding. The weight-average molecular weight was measured using GPC (gel permeation chromatography) with a Tosoh HLC-8320GPC EcoSEC, tetrahydrofuran as the solvent, three Shodex KF-G, KF-805L, and KF-800D columns, at a column temperature of 40°C and a flow rate of 1.2 mL / min. The measurement was obtained as a polystyrene equivalent value detected with a UV-8320 detector at a detection wavelength of 254 nm. In this embodiment, if the resin composition contains two or more types of polyolefin waxes, the weight-average molecular weight of the mixture is used.

[0081] The dropping point of the polyolefin wax is preferably 165°C or lower, more preferably 160°C or lower, even more preferably 155°C or lower, even more preferably 150°C or lower, even more preferably 145°C or lower, even more preferably 140°C or lower, even more preferably 135°C or lower, especially more preferably 130°C or lower, and also preferably 80°C or higher, more preferably 85°C or higher, even more preferably 85°C or higher, even more preferably 90°C or higher, and even more preferably 95°C or higher. The dropping point is defined as the temperature at which the first drop of molten polyolefin wax falls from a standard cup with a 2.8 mm opening after heating the wax from a solid to a liquid state.

[0082] In addition to the above, the descriptions in paragraphs 0063 to 0077 of Japanese Patent Publication No. 2018-070722 and paragraphs 0090 to 0098 of Japanese Patent Publication No. 2019-123809 can also be considered as release agents, and these contents are incorporated herein by reference.

[0083] The resin composition of this embodiment preferably contains 0.01 parts by mass or more of the release agent per 100 parts by mass of the total of the thermoplastic polyester resin and amorphous resin, more preferably 0.1 parts by mass or more, even more preferably 0.2 parts by mass or more, preferably 5 parts by mass or less, more preferably 4 parts by mass or less, even more preferably 3 parts by mass or less, even more preferably 2 parts by mass or less, and may also be 1 part by mass or less. Setting the release agent above the lower limit tends to further improve the release properties of the resulting molded product. Furthermore, setting the release agent below the upper limit can effectively suppress bleed-out of the resulting molded product. The resin composition may contain only one type of release agent or two or more types. If it contains two or more types, it is preferable that the total amount is within the above range.

[0084] <Dyes that transmit laser light> The resin composition in this embodiment preferably contains a dye that transmits laser light. By containing a dye that transmits laser light, the resin composition of this embodiment can be preferably used for forming a transparent resin member during laser welding. More specifically, when using the resin composition of this embodiment as a transparent resin member in a laser-welded molded product, the color of the transparent resin member and the absorbent resin member can be adjusted, resulting in a laser-welded product with excellent design. The dye that transmits laser light is not specifically defined as any dye that transmits a certain percentage or more of the laser light used for laser welding; any known dye can be used. The laser light-transmitting dye includes, for example, a dye that, when combined with polybutylene terephthalate resin (e.g., Novaduran® 5008), 30% by mass of glass fiber (e.g., Nippon Electric Glass Co., Ltd., product name: T-127), and 0.2% by mass of a dye (a dye believed to transmit laser light) to a total of 100% by mass, has a transmittance of 5% or more when the light transmittance is measured. Furthermore, by incorporating the laser light-transmitting dye in this embodiment, for example, the transmittance at a wavelength of 1064 nm can be made 5% or more when the laser-transmitting resin composition is molded to a thickness of 1.5 mm. Pigments that transmit laser light are typically dyes. The laser light-transmitting dye can be appropriately selected according to its application, and its color is not particularly specified. In this embodiment, the laser light-transmitting dye is preferably a black dye composition containing a black dye and / or two or more chromatic dyes. A black dye composition means a composition in which two or more chromatic dyes such as red, blue, and green are combined to produce a black color. A first embodiment of the black pigment composition is a form containing a green pigment and a red pigment. A second embodiment of the black pigment composition is a form containing a red pigment, a blue pigment and a yellow pigment. Specific examples of dyes that transmit laser light include nigrosine, naphthalocyanine, aniline black, phthalocyanine, porphyrin, perinone, quaterylene, azo, azomethine, anthraquinone, pyrazolone, squamate derivatives, perylene, chromium complexes, and immonium, with azomethine, anthraquinone, and perinone being preferred, and anthraquinone and perinone being more preferred among them.

[0085] Examples of commercially available products include the colorants e-BIND LTW-8731H, e-BIND LTW-8701H, and e-BIND LTW-8904 from Orient Chemical Industry Co., Ltd., the colorants Plast Yellow 8000, Plast Red M 8315, Plast Red 8370, and Oil Green 5602 from Arimoto Chemical Co., Ltd., the colorants Macrolex Yellow 3G, Macrolex Red EG, and Macrolex Green 5B from LANXESS, and KP Plast HK, KP Plast Red HG, KP Plast Red H2G, KP Plast Blue R, KP Plast Blue GR, and KP Plast Green G from Kiwa Chemical Industry Co., Ltd. Furthermore, the dyes described in Japanese Patent Publication No. 4157300 and Japanese Patent Publication No. 4040460 can also be used, and these are incorporated herein by reference.

[0086] The resin composition used in this embodiment preferably contains 0.001 to 5 parts by mass of a laser light-transmitting dye per 100 parts by mass of the total of the thermoplastic polyester resin and amorphous resin contained in the resin composition. The lower limit of the content is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, even more preferably 0.5 parts by mass or more, even more preferably 1.0 part by mass or more, and even more preferably 1.5 parts by mass or more. Setting the content above the lower limit results in coloring of the transparent resin member, improving the aesthetic appeal of the laser-welded body. The upper limit of the content is preferably 4 parts by mass or less, more preferably 3.5 parts by mass or less, and even more preferably 3 parts by mass or less. Setting the content below the upper limit effectively suppresses the bleed-out of the laser light-transmitting dye. The laser-transmitting resin composition may contain only one type of laser light-transmitting dye, or it may contain two or more types. When it contains two or more types, it is preferable that the total amount is within the above range.

[0087] <Fibrous filler> The resin composition in this embodiment preferably further contains a fibrous filler. Including a fibrous filler tends to improve the mechanical strength.

[0088] The fibrous filler that can be used in the resin composition in this embodiment is one that has the effect of improving the mechanical properties of the resin composition obtained by being blended with the resin, and any commonly used fibrous filler for plastics can be used. Preferably, fibrous fillers such as glass fibers, carbon fibers, basalt fibers, wollastonite, and potassium titanate fibers can be used, with glass fibers and / or carbon fibers being preferred, and glass fibers being more preferred. It is more preferable to use fibrous fillers that have been surface-treated with a surface treatment agent such as a coupling agent. Glass fibers to which a surface treatment agent has been applied are preferable because they have excellent durability, resistance to humid heat, resistance to hydrolysis, and resistance to thermal shock.

[0089] Any conventionally known surface treatment agent can be used, and specifically, silane coupling agents such as aminosilane, epoxysilane, allylsilane, and vinylsilane are preferred. Among these, aminosilane surface treatment agents are preferred, and specifically, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and γ-(2-aminoethyl)aminopropyltrimethoxysilane are preferred examples.

[0090] In addition, other preferred surface treatment agents include epoxy resin-based surface treatment agents such as novolac-type and bisphenol A-type epoxy resin-based surface treatment agents, with treatment using a novolac-type epoxy resin-based surface treatment agent being particularly preferred. Silane-based surface treatment agents and epoxy resin-based surface treatment agents may be used individually or in combination, and it is also preferable to use both in combination. In this embodiment, glass fibers refer to fibrous glass material, and more specifically, chopped glass fibers, which are bundled together in a manner of 1,000 to 10,000 strands and cut to a predetermined length, are preferred.

[0091] In this embodiment, the glass fibers have a number-average fiber length of 0.5 to 10 mm, and more preferably 1 to 5 mm. By using glass fibers with such a number-average fiber length, the mechanical strength can be further improved. The number-average fiber length is calculated by randomly selecting glass fibers to be measured from an image obtained by observation with an optical microscope, measuring their longest side, and then calculating the number-average fiber length from the obtained measurement values. The observation magnification is 20x, and the number of measurements is 1,000 or more. This roughly corresponds to the cut length. Furthermore, the cross-section of the glass fiber may be circular, elliptical, oblong, rectangular, a rectangle with semicircles attached to both short sides, or cocoon-shaped, but a circular shape is preferred. Here, "circular" includes not only a circular shape in the geometric sense, but also what is commonly referred to as circular in the technical field of this embodiment. The number-average fiber diameter of glass fibers is preferably 4.0 μm or more at the lower limit, more preferably 4.5 μm or more, and even more preferably 5.0 μm or more. The upper limit of the number-average fiber diameter of glass fibers is preferably 15.0 μm or less, and more preferably 14.0 μm or less. Using glass fibers having a number-average fiber diameter within this range tends to yield components with superior mechanical strength. The number-average fiber diameter of glass fibers is calculated by randomly selecting glass fibers to be measured from an image obtained by observing with an electron microscope, measuring the fiber diameter near the center, and obtaining the measured values. The observation magnification is 1,000x, and the number of measurements is 1,000 or more. For glass fibers with a cross-section other than circular, the number-average fiber diameter is calculated as the number-average fiber diameter when converted to a circle with the same area as the cross-sectional area.

[0092] Glass fibers are generally obtained by melt-spinning supplied glass such as E glass (Electrical glass), C glass (Chemical glass), A glass (Alkali glass), S glass (High strength glass), D glass, R glass, and alkali-resistant glass, but any material that can be made into glass fibers can be used and is not particularly limited. In this embodiment, it is preferable to include E glass.

[0093] The glass fibers used in this embodiment are preferably surface-treated with a surface treatment agent such as a silane coupling agent, such as γ-methacrylateoxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, or γ-aminopropyltriethoxysilane. The amount of surface treatment agent applied is preferably 0.01 to 1% by mass of the glass fibers. Furthermore, if necessary, glass fibers may be surface-treated with a lubricant such as a fatty acid amide compound or silicone oil, an antistatic agent such as a quaternary ammonium salt, a resin with film-forming ability such as epoxy resin or urethane resin, or a mixture of a resin with film-forming ability and a heat stabilizer.

[0094] Glass fibers are available commercially. Examples of commercially available products include T-286H, T-756H, T-127, T-289H from Nippon Electric Glass Co., Ltd., DEFT2A from Owens Corning, HP3540 from PPG, and CSG3PA820 from Nitto Boseki Co., Ltd.

[0095] In this embodiment, the content of fibrous filler (preferably glass fiber) in the resin composition is preferably 10 parts by mass or more, more preferably 30 parts by mass or more, even more preferably 40 parts by mass or more, and even more preferably 50 parts by mass or more, per 100 parts by mass of thermoplastic polyester resin contained in the resin composition. Setting it above the lower limit tends to increase the mechanical strength of the resulting member. Furthermore, the upper limit of the fibrous filler content is preferably 70 parts by mass or less, more preferably 65 parts by mass or less, and even more preferably 60 parts by mass or less, per 100 parts by mass of thermoplastic polyester resin. Setting it below the upper limit tends to increase the welding strength of the interface.

[0096] Furthermore, the content of fibrous filler (preferably glass fiber) in the resin composition in this embodiment is preferably 20% by mass or more, and more preferably 25% by mass or more. Moreover, the content of the fibrous filler (preferably glass fiber) is preferably 45% by mass or less, more preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 32% by mass or less. The resin composition in this embodiment may contain only one type of fibrous filler (preferably glass fiber), or it may contain two or more types. When two or more types are included, it is preferable that the total amount is within the above range.

[0097] <Other ingredients> The resin composition in this embodiment may contain other components as needed, as long as they do not significantly impair the desired physical properties. The other components may be present as a single component, or as two or more components in any combination and ratio. Other examples of components include resin additives and fillers other than the fibrous fillers mentioned above. Examples of resin additives include nucleating agents, impact modifiers, lubricants, flame retardants, flame retardant aids, transesterification inhibitors, ultraviolet absorbers, antistatic agents, antifogging agents, antiblocking agents, flow modifiers, plasticizers, and dispersants. The total amount of these other components is preferably 0% by mass or more and less than 10% by mass, more preferably 0% by mass or more and less than 5% by mass, even more preferably 0% by mass or more and less than 3% by mass, and even more preferably 0% by mass or more and less than 1% by mass, based on 100% by mass of the resin composition.

[0098] Other fillers besides fibrous fillers include granular or amorphous fillers such as calcium carbonate, titanium oxide, feldspar minerals, clay, organic clay, and glass beads; plate-like fillers such as talc; and flake-like fillers such as glass flakes, mica, and graphite. The total amount of fillers other than fibrous fillers is preferably 0% by mass or more and less than 10% by mass, more preferably 0% by mass or more and less than 5% by mass, and even more preferably 0% by mass or more and less than 3% by mass, based on 100% by mass of the resin composition.

[0099] In this embodiment, an example of the resin composition is one in which the total of a thermoplastic polyester resin, an amorphous resin, an epoxy compound having an internal epoxide in its molecule, a laser light-transmitting dye, glass fibers, a mold release agent, and a stabilizer, which are added as needed, preferably accounts for 90% by mass or more, more preferably 95% by mass or more, and even more preferably 99% by mass or more.

[0100] The resin composition of this embodiment is preferably less prone to black spots when molded into a product. Specifically, when the resin composition is molded into a 60 mm square plate-shaped product with a thickness of 1.5 mm, and the number of black spots visible to the eye on a test piece is measured three times using an infrared irradiation device, the total value is preferably 9 or less, more preferably 5 or less, even more preferably 3 or less, even more preferably 1 or less, and even more preferably 0.

[0101] <Method for producing resin compositions> The resin composition of this embodiment can be manufactured by conventional methods for preparing resin compositions (e.g., pellets). Typically, each component and various additives, which may be added as desired, are thoroughly mixed together and then melt-kneaded in a single-screw or twin-screw extruder. Alternatively, the resin composition of this embodiment can be prepared by pre-mixing the components, or by pre-mixing only a portion of them, and then supplying the mixture to the extruder using a feeder for melt-kneading. For example, it is preferable to supply glass fibers to an extruder using a side feeder and melt-knead them. Alternatively, some components may be melt-kneaded with a thermoplastic resin to prepare a masterbatch, and then the remaining components may be added to this and melt-kneaded. The thermoplastic resin used for the masterbatch is preferably a polyalkylene terephthalate resin, more preferably a polybutylene terephthalate resin and / or polyethylene terephthalate resin, and even more preferably a polybutylene terephthalate resin.

[0102] Furthermore, the method for producing the resin composition of this embodiment is characterized by including extruding an epoxy compound having an internal epoxide in a ratio of 0.1 to 10 parts by mass per 100 parts by mass of thermoplastic polyester resin. It is also preferable that the distance from the point where the epoxy compound is added to the tip of the screw is 11D or more, and that the process includes a liquid addition step. The resin composition is preferably the resin composition of this embodiment.

[0103] An example of a method for producing the resin composition of this embodiment is a method for producing pellets of the resin composition using an extruder, wherein a twin-screw extruder is used as the extruder, having a raw material feed section, a conveying section, a kneading section, a conveying section including a liquid additive section, a vacuum vent section, a conveying section, and a die section in order from upstream to downstream of the extruder, in which the raw material containing thermoplastic polyester resin supplied from the raw material feed section is melt-kneaded, an epoxy compound having an internal epoxide in its molecule is added in the conveying section downstream thereafter, volatile matter is removed in the vacuum vent section, and it is preferable that the distance from the position where the epoxy compound having an internal epoxide in its molecule is added to the tip of the screw is 11D or more. Furthermore, an example of a method for producing a resin composition when glass fibers are incorporated is a method for producing pellets of the resin composition using an extruder, wherein a twin-screw extruder is used as the extruder, having, in order from upstream to downstream, a raw material feed section, a conveying section, a kneading section, a conveying section including a liquid additive section, a glass fiber supply section, a kneading section, a conveying section, a vacuum vent section, a conveying section, and a die section, in which raw materials including thermoplastic polyester resin supplied from the raw material feed section are melt-kneaded, an epoxy compound having internal epoxides in its molecule is added in the conveying section downstream thereafter, volatile matter is removed in the vacuum vent section, and it is preferable that the distance from the position where the epoxy compound having internal epoxides in its molecule is added to the tip of the screw is 11D or more.

[0104] When the distance from the point where the epoxy compound having an internal epoxide within the molecule is added to the screw tip is 11D or greater, the dispersibility of the epoxy compound is improved, and issues such as extrusion instability and quality inconsistencies can be suppressed. Furthermore, it is preferable that the distance be 54D or less, and even more preferable that it be 28D or less to suppress burning caused by the epoxy compound.

[0105] A twin-screw extruder is preferably used in the method for manufacturing the resin composition of this embodiment. Various types of twin-screw extruders can be used, and the screw rotation method may be co-rotating or counter-rotating, but a co-meshing twin-screw extruder is preferred. In addition, a reduced-pressure vent is usually provided in the twin-screw extruder.

[0106] Figure 5 is a cross-sectional view showing an example of the screw configuration of an extruder used in the manufacturing method of the resin composition of this embodiment. The manufacturing method of the resin composition of this embodiment will be described below with reference to Figure 5.

[0107] Raw materials other than epoxy compounds containing internal epoxides in their molecules, such as thermoplastic polyester resins, are supplied to the extruder from the raw material feed section of a twin-screw extruder. The thermoplastic polyester resin is transported towards the die section, located to the right in Figure 5, while being melted and kneaded by the heating of the extruder barrel and the rotation of the screw. The strands discharged from the discharge die are pelletized in a granulator (not shown).

[0108] The raw material feed section is the part that feeds raw materials such as thermoplastic polyester resin. It consists of the screw at the base of the extruder or the upper opening upstream for raw material feeding, and in the case of an extruder with a side feed screw, it is the feed section for feeding raw materials to that side feed screw.

[0109] The conveying section is the part that conveys raw materials from upstream to downstream using a screw, and consists of a flight screw or the like. A forward-facing full-flight screw is preferred as the conveying screw. The thermoplastic polyester resin supplied from the supply port is conveyed and preheated in the first conveying section.

[0110] Next, the thermoplastic polyester resin is melted in the kneading section. The kneading section is the part where the resin is kneaded, plasticized, or dispersed, and consists of a mixing screw, a kneading disc, and the like. Preferred kneading discs used in the mixing section include R-kneading discs, N-kneading discs, L-kneading discs, L-screws, and seal rings. The mixing section may have a standard full-flight screw for feeding placed between multiple kneading discs.

[0111] An R-type kneading disc, also known as a progressive kneading disc (hereinafter sometimes referred to as R), typically has two or more blades with a twist angle of 10 to 75 degrees. By positioning the blades with a predetermined angle offset in this way, resin can be fed and a strong shearing force can be applied.

[0112] An N-type kneading disc, also called an orthogonal kneading disc (sometimes referred to as N), typically has two or more blades with a twist angle of 75 to 105 degrees. Because the blades are offset by approximately 90 degrees, it has almost no force to move the resin, but it has strong kneading power.

[0113] An L-kneading disc, also known as a reverse-feed kneading disc (sometimes referred to simply as L), typically has two or more blades with a twist angle between -10 and -75 degrees. The L-kneading disc is a pressurizing element that acts to block incoming resin or push back incoming resin. By placing it downstream of the element that promotes kneading, it blocks the resin flow and provides a powerful kneading effect.

[0114] An L-screw, also called a reverse-feed screw, is a screw that spirals in the opposite direction to a normal feed screw. It is an element that can block the resin flow or increase pressure in the direction that the fed resin is returned. Similar to an L-kneading disc, it is installed downstream of the element that promotes kneading to block the resin flow and exert a powerful kneading effect.

[0115] The blades described above are usually elliptical, with flat sections at the two vertices of the ellipse. These blades are also called discs, and each kneading disc is usually composed of 3 to 7 discs. These discs are sometimes roughly triangular and have three vertices, and are also called three-pronged kneading discs. Similarly, there are R, N, and L types. These can also be used in the same way. Among kneading discs, there are also twisted kneading discs, in which the vertices are twisted in the direction of the screw axis, and similar kneading effects can be obtained.

[0116] A seal ring is a ring-shaped component fitted onto a screw, which blocks approximately 70-90% of the flow path, causing the resin flow to stagnate and thereby increasing the resin pressure. Similar to an L-kneading disc, by placing it downstream of the element that promotes kneading, it can dam the resin flow and exert a powerful kneading effect.

[0117] The mixing section is preferably composed of the kneading disc and seal ring described above, but a mixing screw, rotor screw, or reverse-feed full-flight screw may also be used.

[0118] A mixing screw is made by machining the peaks of a screw flight. It is a single- or double-flute feed or reverse-flute screw and is an element with strong shear dispersion force. There are forward-flute notched mixing screws and reverse-flute notched mixing screws.

[0119] A rotor screw has elliptical (two-blade structure) or triangular rotor blades, and can generate strong shear force through the gap (tip clearance) between the rotor and the inner wall of the barrel. A reverse-feed full-flight screw is a screw that operates in the opposite direction to a feed screw and has a strong resin boost pressure.

[0120] Thus, the mixing section refers to the part where the resin is retained, subjected to strong shearing, and melted and mixed. The mixing section can be located in one place or divided into multiple sections. If divided into two sections, the mixing section and conveying section should be arranged in that order. In this invention, the kneading section refers to the beginning and end of the kneading area.

[0121] In the mixing section, sufficient melting of the thermoplastic polyester resin is achieved. Preferably, the epoxy compound is added in the conveying section following this melt-mixing section. The addition position is shown in Figure 5. The distance L from the position where the epoxy compound containing internal epoxides is added to the tip of the screw is preferably in the range of 11D (where D is the inner diameter of the extruder cylinder) or more, as described above.

[0122] There are no particular restrictions on the method of adding an epoxy compound having an internal epoxide to an extruder, but when the epoxy compound is liquid at room temperature, it is preferable to add it to the extruder cylinder from a liquid addition nozzle using a pump. Here, "liquid at room temperature" means that it is liquid at 23°C. Furthermore, if the epoxy compound having an internal epoxide is in a highly viscous state at room temperature, it is preferable to heat it to reduce its viscosity and make it liquid, and then add it to the extruder cylinder from a liquid addition nozzle using a pump. The reason for this is that extruders with cylinder diameters of 40 mm or more, which are often used in mass production lines, typically produce continuously at a standard discharge rate of 200 kg or more, resulting in large production volumes and long production times. In such cases, the method of mixing liquid epoxy compounds at room temperature with other raw materials and supplying them from a feeder to the extruder can lead to the liquid epoxy compounds gradually solidifying and accumulating on the feeder's screw, etc., causing supply problems during production and making continuous production difficult. The pump used is preferably a positive displacement pump, and among these, plunger pumps, diaphragm pumps, gear pumps, and tube pumps are preferred. Among plunger pumps, multi-phase plunger pumps are more preferable in suppressing flow pulsation.

[0123] In the conveying section after the liquid additive section, glass fibers may be supplied from a side feeder. Examples of raw material feeders include twin-screw type and vibrating type. Glass fibers are supplied into the extruder by the side screw.

[0124] Next, in the kneading section, the glass fibers are dispersed and mixed into the resin composition, using a mixing screw, kneading disc, etc. Preferred kneading discs used in the mixing section include R-kneading discs, N-kneading discs, L-kneading discs, and L-screws. The mixing section may have a standard full-flight screw for feeding placed between multiple kneading discs.

[0125] The material is then transported downstream to the die section by a conveying unit, but typically a pressure-reducing vent is located in the middle of the conveying unit. Vacuum vents are installed, for example, to remove volatile components generated from plasticized resins or additives. Volatile components include volatile components (low molecular weight components) contained in the raw materials and low molecular weight components generated during plasticization. The degree of pressure reduction of the depressurization vent is preferably in the range of -0.03 MPa to -0.099 MPa, with atmospheric pressure being 0 MPa. After the vacuum vent, there is a conveying section and the tip of the screw. The strand exiting the die is water-cooled and then cut in a pelletizer to obtain pellets.

[0126] <Molded articles and methods for manufacturing molded articles> The resin composition of this embodiment is molded according to a known method. That is, the molded article of this embodiment is formed from the resin composition of this embodiment. The method for manufacturing the molded product is not particularly limited, and any molding method commonly used for thermoplastic resin compositions can be arbitrarily employed. Examples include injection molding, ultra-high-speed injection molding, injection compression molding, two-color molding, hollow molding methods such as gas-assisted molding, molding using insulated molds, molding using rapidly heated molds, foam molding (including supercritical fluids), insert molding, IMC (in-mold coating) molding, extrusion molding, sheet molding, thermoforming, rotational molding, lamination molding, press molding, blow molding, etc., with injection molding being preferred among these. Details of injection molding can be found in paragraphs 0113 to 0116 of Japanese Patent No. 6183822, which are incorporated herein by reference. In this embodiment, it is particularly preferable that the product be used for molding in an injection molding machine equipped with a gate having a gate diameter of 0.5 mm or less, or in an injection molding machine equipped with a hot runner. Generally, if burnt foreign matter is present in the resin composition, it can clog the molding machine, particularly at the gate tip, causing molding problems such as insufficient resin filling into the mold. In this embodiment, since it is possible to reduce the occurrence of burnt foreign matter, molding can be easily performed even with molding machines that have mold structures with small gate diameters of 0.5 mm or less, such as so-called pin gates. Furthermore, the resin composition of this embodiment is also suitable for hot runner molding. Hot runners are a mechanism that extracts only the molded product by keeping the sprue runner in a molten state, but they are unsuitable for resins with poor thermal stability because they remain in a molten state. The resin composition of this embodiment has excellent thermal stability, and even if it remains in the molten state, it is less likely to produce burnt foreign matter and can be successfully molded using hot runner molding.

[0127] <Application> The resin composition of this embodiment is not particularly limited in its use, and can be widely used in known applications where resin compositions are generally used. The resin composition of this embodiment can be used, for example, as a composition for forming a transparent resin member during laser welding. That is, the resin composition of this embodiment acts as a light-transmitting resin composition, and a molded article formed from such a light-transmitting resin composition becomes a resin member that transmits laser light during laser welding. The transparent resin member can then be used as a laser-welded body by laser welding it with a molded article formed from a light-absorbing resin composition (a resin member that absorbs laser light during laser welding). Here, the light-absorbing resin composition includes a thermoplastic resin and a light-absorbing dye (for example, carbon black). It may also contain an inorganic filler.

[0128] Details of the laser welding method and the light-absorbing resin composition can be found in paragraphs 0083-0092 of International Publication No. 2021 / 225154, which are incorporated herein by reference.

[0129] The laser light source used for laser welding can be determined according to the absorption wavelength of the light-absorbing dye, with lasers in the wavelength range of 800 to 1100 nm being preferred. Examples of laser light types include solid-state lasers, fiber lasers, semiconductor lasers, gas lasers, and liquid lasers. For example, YAG (yttrium aluminum garnet crystal) lasers (wavelengths 1064 nm, 1070 nm) and LD (laser diode) lasers (wavelengths 808 nm, 840 nm, 940 nm, 980 nm) can be preferably used. Among these, laser light with wavelengths of 940 nm, 980 nm, and 1070 nm is preferred.

[0130] The resin composition or molded article of this embodiment can be applied to a variety of uses, specifically, various storage containers, electrical and electronic equipment components, office automation (OA) equipment components, home appliance components, mechanical mechanism components, vehicle mechanism components, etc. In particular, it can be suitably used for food containers, pharmaceutical containers, oil and fat product containers, hollow vehicle components (various tanks, intake manifold components, camera housings), vehicle electrical components (various control units, ignition coil components, etc.), motor components, various sensor components, connector components, switch components, circuit breaker components, relay components, coil components, transformer components, lamp components, etc.

[0131] In particular, the laser-welded body of this embodiment is preferably used for in-vehicle camera components, sensor case components, motor components, and electronic control components. More specifically, it is suitable for in-vehicle camera components and in-vehicle camera modules including in-vehicle camera components, housings for millimeter-wave radar, housings for ECU cases, housings for sensor cases such as sonar sensors, and housings for motor components such as electric parking brakes.

[0132] The method for reducing burnt foreign matter in a resin composition of this embodiment is a method for reducing burnt foreign matter in a resin composition containing 1.0 to 10 parts by mass of an epoxy compound per 100 parts by mass of a thermoplastic polyester resin, characterized in that the epoxy compound is an epoxy compound having an internal epoxide within its molecule. Preferably, the resin composition contains 1 to 50 parts by mass of amorphous resin and 2.2 to 10 parts by mass of epoxy compound having internal epoxides in its molecule, per 100 parts by mass of thermoplastic polyester resin. Details of the method for reducing burnt foreign matter can be found in the above description, and preferred ranges, etc., are the same as above. [Examples]

[0133] The present invention will be described in more detail below with reference to examples. The materials, amounts used, proportions, processing content, and processing procedures shown in the following examples can be modified as appropriate, as long as they do not depart from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. When it is difficult to obtain the measuring instruments and the like used in the examples due to their obsolescence or the like, measurements can be made using other instruments having equivalent performance.

[0134] 1. Raw materials The following raw materials were used.

Table 1

[0135] 2. Examples 1 - 6, Comparative Examples 1 - 3 <Compound> The components shown in Table 1 were uniformly mixed in the ratios (parts by mass) shown in Table 2 or Table 3 using a tumbler mixer for the components other than the glass fiber. The obtained mixture was fed into a twin - screw extruder (TEX30α manufactured by Japan Steel Works, Ltd.) through the main feed port. The cylinder set temperature of the first kneading section was set at 260°C, and the glass fiber was fed through a side feeder. The cylinder temperature after adding the glass fiber was set at 240°C, and the resin composition was melt - kneaded under the conditions of a discharge rate of 40 kg / h and a screw rotation speed of 200 rpm, and then rapidly cooled in a water tank and pelletized using a pelletizer to obtain pellets of the resin composition.

[0136] <Laser welding strength after PCT treatment> <<Molding of the transparent resin member>> After drying the above resin pellets at 120°C for 5 hours, using an injection molding machine (J55 manufactured by Japan Steel Works, Ltd.), they were molded at a cylinder temperature of 260°C and a mold temperature of 60°C to produce a molded product (transparent resin member I) with a thickness of 1.5 mm as shown in Fig. 1.

[0137] <<Molding of the absorbent resin member>> Polybutylene terephthalate resin (NOVADURAN 5010G30X4 / BK2) manufactured by Mitsubishi Chemical Corporation was dried at 120°C for 5 hours, and then using an injection molding machine (J55 manufactured by Japan Steel Works, Ltd.), it was molded at a cylinder temperature of 260°C and a mold temperature of 60°C to produce a molded product (absorbent resin member II) as shown in Fig. 2.

[0138] As shown in Figures 3 and 4, holes 21 and 22 were made in the absorbent resin member II, respectively, and jigs 23 and 24 for measuring welding force were placed inside. A lid-shaped transparent resin member I was then placed on top of the box-shaped absorbent resin member II, and a laser light source was positioned vertically above the flange portion where the transparent resin member I and the absorbent resin member II overlapped. A pressing force of 4.92 N / mm (pressing force during welding) was applied inward from both sides in the thickness direction to the overlapping portion of the transparent resin member I and the absorbent resin member II using a glass plate, while the laser was irradiated to obtain a laser-welded body. The portion labeled X in Figure 3 is the portion where the laser was irradiated. The welding equipment is as follows:

[0139] <<Galvanoscanner-type laser welding>> Laser device: IPG YLR-300-AC-Y14 Wavelength: 1070nm Collimator: 7.5mm Laser type: Fiber Laser intensity (output): 100W Galvanometer scanner: ARGES Fiber Elephants21 Aperture: 21mm Laser irradiation speed: 900 mm / s Number of laser irradiation passes: 10 passes Circumference of welded area: 137mm The laser beam was defocused and the laser scanner was positioned so that the spot diameter irradiated onto the welding surface was 1.6 mm in diameter.

[0140] <<Laser welding strength>> As shown in Figure 4, measuring jigs 25 and 26 were inserted into the top and bottom surfaces of the box made of the permeable resin member I and absorbent resin member II prepared above, respectively, and connected to jigs 23 and 24 housed inside. The box was then pulled vertically (tensile speed: 5 mm / min) to measure the strength at which the permeable resin member I and absorbent resin member II separated (welding strength, unit: N). Furthermore, the equipment used was a 100kN Tensilon universal testing machine manufactured by ORIENTEC.

[0141] <<Laser welding strength after PCT treatment>> The laser welded body obtained above was subjected to PCT treatment for 50 hours under the conditions of 121 °C and 2 atm, and the laser welding strength was measured. Also, the retention rate (unit: %) after PCT treatment was shown when the laser welding strength immediately after laser welding was set to 100%.

[0142] <Tensile strength after PCT treatment> After drying the pellets obtained above at 120 °C for 5 hours, injection molding was performed using an injection molding machine ("J85AD" manufactured by Japan Steel Works, Ltd.) under the conditions of a cylinder temperature of 250 °C and a mold temperature of 80 °C to obtain ISO multipurpose test pieces (thickness: 4 mm). In addition to the initial tensile strength, the tensile strength after PCT treatment for 150 hours and 200 hours under the conditions of 121 °C and 2 atm was measured. Also, the retention rate (unit: %) after PCT treatment was shown when the tensile strength before PCT treatment was set to 100%. Also, the retention rate (unit: %) after PCT treatment was calculated when the initial tensile strength was set to 100%.

[0143] <Light transmittance (transmittance)> After drying the pellets obtained above at 120 °C for 5 hours, a plate-shaped molded product with a thickness of 1.5 mm and a size of 60 mm square was injection molded using an injection molding machine ("NEX80" manufactured by Nissei Plastic Industrial Co., Ltd.) under the conditions of a cylinder temperature of 260 °C and a mold temperature of 60 °C. The obtained plate was used with an ultraviolet-visible spectrophotometer to measure the light transmittance (unit: %) of 1064 nm at a point 45 mm from the gate and at the center of the test plate width. An ultraviolet-visible spectrophotometer "UV-3100PC" manufactured by Shimadzu Corporation equipped with an integrating sphere was used.

[0144] <Number of black dots> Using the test piece used for the measurement of the above light transmittance, the number of black dots visually confirmed from the test piece was measured using an infrared irradiation device. The measurement was performed 3 times, and the total value was described.

[0145] 3. Example 7 <Compound> A twin-screw extruder "TEX54αIII" manufactured by Japan Steel Works, Ltd. (14 barrels total, L / D = 49, cylinder diameter = 58 mm) was used. The following explanation will be given with reference to Figure 5. The total discharge rate was set to 500 kg / h, and the raw materials were supplied at the same mixing ratio as in Example 1. Epoxy compound 1 was heated and supplied by a plunger pump from a liquid-addition nozzle installed in barrel C8. PBT, release agent 1, and dye masterbatch were supplied individually from feeders, and the remaining raw materials in powder form, including PC, were supplied all at once after mixing. PBT, release agent 1, dye masterbatch, and mixed raw materials were supplied from barrel C1. Glass fibers were supplied from a side screw at barrel C10. Twin-screw feeders were used in all cases. A vacuum vent was placed at the location of barrel C13. The distance L from the epoxy compound addition point of barrel C8 to the tip of the downstream barrel C14 was 23.8D. After 10 hours of operation, there were no production problems such as a decrease in raw material supply or strand breakage, and continuous operation was possible. The cylinder temperature was set to 270°C for the first kneading section, 240°C for the liquid addition section, 200°C for the cylinder temperature after glass fiber addition, and 270°C for the die head temperature. The resin composition was melt-kneaded under these conditions with a screw rotation speed of 300 rpm, rapidly cooled in a water bath, and pelletized using a pelletizer to obtain pellets of the resin composition. The obtained pellets were evaluated in the same manner as in Example 1.

[0146] [Table 2]

[0147] [Table 3]

[0148] As is clear from the results above, the resin composition of this embodiment was found to have a low number of black spots and suppress the generation of burnt foreign matter. Furthermore, it exhibited excellent laser welding strength and tensile strength after moist heat treatment. Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications are possible without departing from the intent and scope of the invention. [Explanation of Symbols]

[0149] 21, 22 holes 23, 24 Fixtures for measuring welding force 25, 26 Measuring jigs

Claims

1. Per 100 parts by mass of thermoplastic polyester resin, A resin composition comprising 2.2 parts by mass or more and 10 parts by mass or less of an epoxy compound having an internal epoxide within its molecule.

2. The resin composition according to claim 1, wherein the resin composition is molded into a plate-shaped molded product with a thickness of 1.5 mm and a size of 60 mm square, and the total value of the number of black spots that can be visually confirmed from a test piece is measured three times using an infrared irradiation device is 9 or less.

3. Furthermore, the resin composition according to claim 1 or 2, further comprising an amorphous resin.

4. The resin composition according to claim 1 or 2, comprising 2.5 parts by mass or more and 10 parts by mass or less of an epoxy compound having an internal epoxide within the molecule, per 100 parts by mass of a thermoplastic polyester resin.

5. The resin composition according to claim 1 or 2, wherein the content of epoxy compounds other than epoxy compounds having internal epoxides in the molecule is 0.5 parts by mass or less per 100 parts by mass of thermoplastic polyester resin.

6. Furthermore, the resin composition according to claim 1 or 2, comprising 1 to 60 parts by mass of amorphous resin per 100 parts by mass of thermoplastic polyester resin.

7. Furthermore, the resin composition according to claim 1 or 2, further comprising 1 to 50 parts by mass of amorphous resin with respect to 100 parts by mass of thermoplastic polyester resin.

8. The resin composition according to claim 3, wherein the amorphous resin includes a polycarbonate resin.

9. The resin composition according to claim 1 or 2, wherein the thermoplastic polyester resin comprises a polybutylene terephthalate resin.

10. The resin composition according to claim 1 or 2, wherein the epoxy compound having an internal epoxide within the molecule comprises an epoxidized natural oil or fat.

11. The resin composition according to claim 1 or 2, wherein the epoxy compound having an internal epoxide within the molecule comprises linseed oil and / or soybean oil.

12. A resin composition according to claim 1 or 2, for forming a transparent resin member during laser welding.

13. The resin composition according to claim 1 or 2, wherein the epoxy compound having an internal epoxide within the molecule has a ratio of 0 to 10 moles of structure (B) to 100 moles of structure (A). 【Chemistry 1】 (In structure (A), * indicates a connection point with another part.) 【Chemistry 2】 (In structure (B), * indicates a connection point with another part.)

14. The resin composition according to claim 1 or 2, wherein the content of the epoxy compound having an internal epoxide in the molecule in the resin composition is 1.2 to 3.1% by mass, based on 100% by mass of the resin composition.

15. The thermoplastic polyester resin includes a polybutylene terephthalate resin, Furthermore, the mixture contains 1 to 60 parts by mass of amorphous resin per 100 parts by mass of thermoplastic polyester resin. The amorphous resin includes a polycarbonate resin. The epoxy compound having an internal epoxide within the molecule comprises linseed oil and / or soybean oil. The resin composition according to claim 1, for forming a transparent resin member during laser welding.

16. The resin composition was molded into a 60 mm square plate-shaped molded product with a thickness of 1.5 mm, and the number of black spots visible to the test piece was measured three times using an infrared irradiation device. The total value was 9 or less. The epoxy compound having an internal epoxide within the molecule is included in an amount of 2.5 parts by mass or more and 10 parts by mass or less per 100 parts by mass of thermoplastic polyester resin. The content of epoxy compounds other than epoxy compounds having internal epoxides in the molecule is 0.5 parts by mass or less per 100 parts by mass of thermoplastic polyester resin. Furthermore, the mixture contains 1 to 50 parts by mass of amorphous resin per 100 parts by mass of thermoplastic polyester resin. The amorphous resin includes a polycarbonate resin. The thermoplastic polyester resin includes a polybutylene terephthalate resin, The epoxy compound having an internal epoxide within the molecule comprises linseed oil and / or soybean oil. It is for forming transparent resin components during laser welding. The epoxy compound having an internal epoxide within the molecule has a ratio of 0 to 10 moles of structure (B) per 100 moles of structure (A). The resin composition according to claim 1, wherein the content of the epoxy compound having an internal epoxide in the molecule in the resin composition is 1.2 to 3.1% by mass, based on 100% by mass of the resin composition. 【Transformation 3】 (In structure (A), * indicates a connection point with another part.) 【Chemistry 4】 (In structure (B), * indicates a connection point with another part.)

17. The resin composition according to claim 1, 2, 15, or 16, for molding in an injection molding machine equipped with a gate having a gate diameter of 0.5 mm or less, or an injection molding machine equipped with a hot runner.

18. A molded article formed from the resin composition according to claim 1, 2, 15, or 16.

19. The molded article according to claim 18, wherein the laser-welded body is a transparent resin member.

20. Pellets of the resin composition according to claim 1, 2, 15, or 16.

21. A molded article formed from the pellets described in claim 20.

22. A method for reducing burnt foreign matter in a resin composition containing 1.0 to 10 parts by mass of an epoxy compound per 100 parts by mass of thermoplastic polyester resin, A reduction method comprising using an epoxy compound having an internal epoxide within the molecule as the epoxy compound.

23. The reduction method according to claim 22, wherein the resin composition comprises 2.2 to 10 parts by mass of an epoxy compound having an internal epoxide in its molecule, per 100 parts by mass of a thermoplastic polyester resin.

24. Furthermore, the reduction method according to claim 22 or 23, further comprising 1 to 50 parts by mass of amorphous resin.

25. A method for producing a resin composition, comprising blending 100 parts by mass of a thermoplastic polyester resin with an epoxy compound having an internal epoxide in its molecule in a ratio of 0.1 parts by mass to 10 parts by mass, and then extruding the mixture.

26. A method for producing resin composition pellets according to claim 25, wherein the distance from the position where the epoxy compound is added to the tip of the screw is 11D or more, and the method includes a liquid addition step.

27. A method for producing pellets of the resin composition according to claim 25, wherein the resin composition is the resin composition according to claim 1, 2, 15, or 16.

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