Resin composition, pellets, molded articles, and method for suppressing discoloration

Abstract

To provide a resin composition that offers excellent resistance to moisture and heat, and can provide molded articles that suppress discoloration during heating, as well as pellets, molded articles, and a method for suppressing discoloration. [Solution] The resin composition according to this disclosure comprises 0.01 to 30 parts by mass of talc having a crystalline silica content of less than 0.1% by mass and 0.01 to 30 parts by mass of an epoxy compound having an internal epoxide in its molecule, per 100 parts by mass of a thermoplastic resin.

Description

[Technical Field]

[0001] The present invention relates to a resin composition, pellets, molded articles, and a method for suppressing discoloration. [Background technology]

[0002] Thermoplastic resins are widely used in various molding materials. It is known that epoxy compounds are added to thermoplastic resins to improve their hydrolysis resistance and heat and humidity resistance (Patent Documents 1 and 2). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-161335 [Patent Document 2] Japanese Patent Publication No. 2021-063196 [Overview of the project] [Problems that the invention aims to solve]

[0004] Here, the inventors considered using an epoxy compound having an internal epoxide within the molecule (sometimes referred to as an "internal epoxide-containing epoxy compound" in this specification) as the epoxy compound, from the viewpoint of further improving heat and humidity resistance. Conventionally, epoxy compounds used in thermoplastic resins have epoxy groups at their ends. However, by incorporating an internal epoxide-containing epoxy compound, higher heat and humidity resistance can be expected compared to the case where commonly used epoxy compounds with epoxy groups at their ends are used. However, it was found that using epoxy compounds containing internal epoxides can sometimes cause discoloration when the molded product is heated. The present invention aims to solve these problems and to provide a resin composition that has excellent moisture and heat resistance and can provide molded articles that can suppress discoloration when heated, as well as pellets, molded articles, and a method for suppressing discoloration. [Means for solving the problem]

[0005] Based on the above problems, the inventors conducted research and found that the above problems can be solved by blending a thermoplastic resin with an epoxy compound having an internal epoxide in its molecule, along with talc having a crystalline silica content of less than 0.1% by mass. Specifically, the above problem was solved by the following means. [1] Per 100 parts by mass of thermoplastic resin, 0.01 to 30 parts by mass of talc with a crystalline silica content of less than 0.1% by mass and A resin composition comprising 0.01 to 30 parts by mass of an epoxy compound having an internal epoxide within its molecule. [2] The resin composition according to [1], wherein the thermoplastic resin comprises a crystalline resin. [3] The resin composition according to [1], comprising the thermoplastic resin polybutylene terephthalate resin. [4] The resin composition according to [1], wherein the thermoplastic resin comprises a polybutylene terephthalate resin having an intrinsic viscosity of 0.70 to 1.30 dL / g. A pellet of the resin composition described in any one of [5], [1], to [4]. A molded article formed from any one of the resin compositions described in [6], [1], to [4]. A molded product formed from the pellets described in [7] and [5]. [8] A method for suppressing discoloration of a molded article formed from a resin composition comprising 0.01 to 30 parts by mass of an epoxy compound having an internal epoxide in its molecule, per 100 parts by mass of a thermoplastic resin, A method for suppressing discoloration, comprising blending the resin composition with talc having a crystalline silica content of less than 0.1% by mass in a ratio of 0.01 to 30 parts by mass per 100 parts by mass of thermoplastic resin. [Effects of the Invention]

[0006] According to the present invention, a resin composition capable of providing a molded product having excellent heat and humidity resistance and capable of suppressing discoloration during heating, as well as pellets, molded products, and a discoloration suppression method, have become available.

Mode for Carrying Out the Invention

[0007] Hereinafter, the mode for carrying out the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. Note that the following present embodiment is an exemplification for explaining the present invention, and the present invention is not limited only to the present embodiment. In this specification, "~" is used to mean including the numerical values described before and after it as the lower limit value and the upper limit value. Also, any combination of the upper limit value and the lower limit value of the numerical values in this specification can be cited as an example of the present embodiment. In this specification, a combination of preferred embodiments is a more preferred embodiment. In this specification, unless otherwise specified, various physical property values and characteristic values are those at 23°C.

[0008] In this specification, unless otherwise specified, the weight average molecular weight and the number average molecular weight are measured by the GPC (gel permeation chromatography) method using HLC-8320GPC EcoSEC manufactured by Tosoh Corporation, using tetrahydrofuran as the solvent, using Shodex KF-G, KF-805L×3, and KF-800D as the columns, at a column temperature of 40°C and a flow rate of 1.2 mL / min, and detected at a detection wavelength of 254 nm, and are values in terms of polystyrene conversion.

[0009] When the measurement methods and the like described according to the standards shown in this specification differ depending on the year, unless otherwise specified, they are based on the standards as of January 1, 2024. When the measurement methods and the like described according to the standards shown in this specification have been abolished as of January 1, 2024, they are based on the standards at the time of abolition.

[0010] The resin composition of this embodiment is characterized by containing, per 100 parts by mass of thermoplastic resin, 0.01 to 30 parts by mass of talc having a crystalline silica content of less than 0.1% by mass, and 0.01 to 30 parts by mass of an epoxy compound having an internal epoxide in its molecule. By adopting this configuration, a resin composition can be obtained that provides molded products with excellent resistance to moisture and heat, and that can suppress discoloration during heating.

[0011] By blending an epoxy compound with a thermoplastic resin, hydrolysis of the thermoplastic resin is suppressed, and a molded product with excellent heat and humidity resistance can be obtained. Here, the inventors have found that using an epoxy compound having an internal epoxide within the molecule further improves heat and humidity resistance. This is presumed to be because, when using an epoxy compound having an internal epoxide within the molecule, the reaction of the epoxy groups proceeds less during the melt-kneading of each material compared to an epoxy compound having epoxy groups at the molecular ends, resulting in a larger amount of epoxy groups remaining in the molded product after molding. However, epoxy compounds containing internal epoxides within the molecule are prone to decomposition when heated because the epoxy groups are located in internal positions such as the main chain. Therefore, molded products tend to discolor easily when heated. In this embodiment, it is presumed that the discoloration of the molded product during heating was suppressed by incorporating talc with a crystalline silica content of less than 0.1% by mass. In other words, it is presumed that incorporating talc with a crystalline silica content of less than 0.1% by mass resulted in a stronger whiteness, improved opacity, and made the discoloration of the molded product less visually noticeable. Specifically, it is presumed that reducing the crystalline silica content in the talc alters the electrical properties of the talc surface, making it easier to disperse the talc in the resin composition, increasing its visible whiteness, and thus improving its opacity. In other words, it is presumed that by using an epoxy compound having an internal epoxide within the molecule in combination with talc containing less than 0.1% by mass of crystalline silica, a resin composition was obtained that provides molded articles with excellent resistance to moisture and heat, and that can suppress discoloration during heating. Furthermore, it is presumed that the tensile strain of the molded product tends to improve because the talc is more easily dispersed in the resin composition, thereby suppressing talc aggregation.

[0012] 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.

[0013] <Thermoplastic resin> The resin composition of this embodiment includes a thermoplastic resin. The thermoplastic resin may be a crystalline thermoplastic resin or an amorphous thermoplastic resin, but a crystalline thermoplastic resin is preferred. In particular, by using a crystalline thermoplastic resin in combination with talc containing less than 0.1% by mass of crystalline silica, the electrical properties of the talc surface change, making it easier for the talc to disperse in the resin composition. This allows the resin composition to crystallize in a balanced manner, resulting in increased visible whiteness and improved opacity. Examples of thermoplastic resins are not specifically defined, but include polyester resins such as polyethylene terephthalate resin, polytrimethylene terephthalate resin, and polybutylene terephthalate resin; polyamide resins; polycarbonate resins; styrene resins; polyolefin resins such as polyethylene resin, polypropylene resin, and cycloolefin resin; polyacetal resins; polyimide resins; polyphenylene sulfide resins, polyether ether ketone resins (PEEK), polytetrafluoroethylene resins, polyvinyl chloride resins, polyetherimide resins; polyurethane resins; polyphenylene ether resins; polysulfone resins; polymethacrylate resins; and it is preferable that crystalline thermoplastic resins are included.

[0014] Examples of thermoplastic resin blend configurations in this embodiment include the following: (1) 90% by mass or more (preferably 95% by mass or more, more preferably 97% by mass or more) of the thermoplastic resin contained in the resin composition is polyalkylene terephthalate resin (preferably polybutylene terephthalate resin). (2) 70 to 100% by mass of the thermoplastic resin contained in the resin composition is polyalkylene terephthalate resin (preferably polybutylene terephthalate resin), and 0 to 30% by mass is styrene resin and / or polycarbonate resin. (3) In (2) above, 90% by mass or more (preferably 95% by mass or more, more preferably 97% by mass or more) of the thermoplastic resin contained in the resin composition is polyalkylene terephthalate resin (preferably polybutylene terephthalate resin) and selectively blended styrene resin and / or polycarbonate resin. Details of styrene resins and polycarbonate resins can be found in paragraphs 0023 to 0039, which are incorporated herein by reference.

[0015] The crystalline thermoplastic resin more preferably contains a crystalline polyester resin, more preferably a polyalkylene terephthalate resin, and even more preferably a polybutylene terephthalate resin. In this embodiment, the polyalkylene terephthalate resin preferably includes polyethylene terephthalate resin and / or polybutylene terephthalate resin, and more preferably includes at least polybutylene terephthalate resin.

[0016] More specifically, the polyalkylene terephthalate resin is a polyester obtained by polycondensation of terephthalic acid as a dicarboxylic acid compound and a diol, and may be either a homopolyester or a copolyester.

[0017] As the dicarboxylic acid compound constituting the polyalkylene terephthalate resin, terphthalic acid compounds or their ester-forming derivatives are preferably used. Aromatic dicarboxylic acids other than terephthalic acid can also be used in combination, such as 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-terphenylene-4,4'-dicarboxylic acid, pyridine-2,5-dicarboxylic acid, etc. These can be used in polycondensation reactions not only as free acids but also as ester-forming derivatives such as dimethyl esters. Among the above, isophthalic acid or its ester-forming derivatives are particularly preferred for use.

[0018] Furthermore, in small amounts, terephthalic acid or the above-mentioned aromatic dicarboxylic acids may 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.

[0019] Examples of dihydroxy compounds constituting polyalkylene terephthalate 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. Among these, butanediol and ethylene glycol are particularly preferred.

[0020] Furthermore, 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. Aromatic diols such as hydroquinone, resorcinol, naphthalenediol, dihydroxydiphenyl ether, and 2,2-bis(4-hydroxyphenyl)propane can also be used.

[0021] 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.

[0022] As the polyalkylene terephthalate resin, it is preferable to use one that mainly consists of a polycondensation of terephthalic acid and a diol, that is, one in which more than 50% by mass of the total resin, preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and even more preferably 99% by mass or more consists of this polycondensate. As the diol, an aliphatic diol is preferred, 1,4-butanediol or ethylene glycol is preferred, and 1,4-butanediol is more preferred.

[0023] The amount of terminal carboxyl groups in the polyalkylene terephthalate resin (preferably polybutylene terephthalate resin) can be appropriately selected and determined, but is usually 80 eq / ton or less, preferably 50 eq / ton or less, more preferably 30 eq / ton or less, even more preferably 20 eq / ton or less, and most preferably 15 eq / ton or less. Keeping it below the above upper limit tends to improve the hydrolysis resistance of the resin composition. There is no particular lower limit for the amount of terminal carboxyl groups, but is preferably 1 eq / ton or more, more preferably 5 eq / ton or more, and even more preferably usually 10 eq / ton or more.

[0024] The amount of terminal carboxyl groups in polyalkylene terephthalate resin is measured by dissolving 0.5 g of resin in 25 mL of benzyl alcohol and titrating with a 0.01 mol / L benzyl alcohol solution of sodium hydroxide. The amount of terminal carboxyl groups can be adjusted by any conventionally known method, such as adjusting polymerization conditions like the raw material ratio, polymerization temperature, and reduced pressure method during polymerization, or by reacting with a chelating agent.

[0025] The intrinsic viscosity of the polyalkylene terephthalate resin (preferably polybutylene terephthalate resin) is preferably 0.70 dL / g or higher, more preferably 0.80 dL / g or higher, even more preferably 0.90 dL / g or higher, even more preferably 0.95 dL / g or higher, even more preferably 1.00 dL / g or higher, and even more preferably 1.05 dL / g or higher. Furthermore, the intrinsic viscosity of the polyalkylene terephthalate resin (preferably polybutylene terephthalate resin) is preferably 1.30 dL / g or lower, and more preferably 1.20 L / g or lower. Setting it above the lower limit tends to further improve moldability. Also, setting it below the upper limit tends to further improve tensile strain.

[0026] Intrinsic viscosity is measured by the following method. Dissolve polyalkylene terephthalate resin pellets 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. Then, cool to 30°C. Using a fully automated solution viscometer, measure the drop time of the sample solution and the drop time of the solvent alone at 30°C, and calculate the intrinsic viscosity 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). HK is Huggins' constant. H 0.33 was adopted. The fully automatic solution viscometer used is manufactured by Shibayama Kagaku Co., Ltd. If the resin composition of this embodiment contains two or more polyalkylene terephthalate resins, the viscosity shall be the intrinsic viscosity of the mixture.

[0027] Preferred polyalkylene terephthalate resins are those in which 95 mol% or more of the acid component is terephthalic acid and 95 mol% or more of the alcohol component is an aliphatic diol. Typical examples include polybutylene terephthalate resin and polyethylene terephthalate resin. These are preferably close to homopolyesters, meaning that 95 mol% or more of the total resin consists of a terephthalic acid component and a 1,4-butanediol or ethylene glycol component. The polyalkylene terephthalate resin is preferably polybutylene terephthalate resin and / or polyethylene terephthalate resin. In particular, the polyalkylene terephthalate resin preferably contains polybutylene terephthalate resin as its main component, and it is preferable that the amount of polybutylene terephthalate resin exceeds 50% by mass. In this case, it is also preferable that polyethylene terephthalate resin is included in an amount of less than 50% by mass.

[0028] Polybutylene terephthalate resin can be produced by melt polymerization of a dicarboxylic acid component mainly composed of terephthalic acid or ester derivatives thereof, and a diol component mainly composed of 1,4-butanediol, in a batch or continuous manner. Furthermore, after producing a low molecular weight polybutylene terephthalate resin by melt polymerization, the degree of polymerization (or molecular weight) can be increased to a desired value by further solid-phase polymerization under a nitrogen atmosphere or reduced pressure.

[0029] A preferred manufacturing method for polybutylene terephthalate resin involves the continuous melt polycondensation of a dicarboxylic acid component mainly composed of terephthalic acid and a diol component mainly composed of 1,4-butanediol.

[0030] The catalyst used in carrying out the esterification reaction may be one of the conventionally known ones, such as titanium compounds, tin compounds, magnesium compounds, and calcium compounds. Among these, titanium compounds are particularly preferred. Specific examples of titanium compounds as esterification catalysts include titanium alcoholates such as tetramethyl titanate, tetraisopropyl titanate, and tetrabutyl titanate, and titanium phenolates such as tetraphenyl titanate.

[0031] The polybutylene terephthalate resin may be a polybutylene terephthalate resin modified by copolymerization (hereinafter sometimes referred to as "modified polybutylene terephthalate resin"), but specific preferred copolymers include polyester ether resins copolymerized with polyalkylene glycols (particularly polytetramethylene glycol), dimer acid copolymerized polybutylene terephthalate resins, and isophthalic acid copolymerized polybutylene terephthalate resins.

[0032] When using a polyester ether resin copolymerized with polytetramethylene glycol as the modified polybutylene terephthalate resin, the proportion of the tetramethylene glycol component in the copolymer is preferably 3 to 40% by mass, more preferably 5 to 30% by mass, and even more preferably 10 to 25% by mass. When using a dimer acid copolymerized polybutylene terephthalate resin as the modified polybutylene terephthalate resin, the proportion of the dimer acid component to the total carboxylic acid component is preferably 0.5 to 30 mol%, more preferably 1 to 20 mol%, and even more preferably 3 to 15 mol% as carboxylic acid groups. When using an isophthalic acid copolymerized polybutylene terephthalate resin as the modified polybutylene terephthalate resin, the proportion of isophthalic acid components to the total carboxylic acid components is preferably 1 to 30 mol%, more preferably 1 to 20 mol%, and even more preferably 3 to 15 mol% as carboxylic acid groups. Among modified polybutylene terephthalate resins, polyester ether resin copolymerized with polytetramethylene glycol and isophthalic acid copolymerized polybutylene terephthalate resin are preferred. The thermoplastic resin used in this embodiment may be recycled products (including recovered products, material recycled products, chemical recycled products, etc.), rejected products, or scraps from thermoplastic resin molding.

[0033] The thermoplastic resin content in the resin composition of this embodiment is preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 85% by mass or more, and depending on the application, it may be 90% by mass or more, 95% by mass or more, or 97% by mass or more. Furthermore, the upper limit in the resin composition is the amount in which all components other than talc, in which the epoxy compound having an internal epoxide in the molecule and crystalline silica content is less than 0.1% by mass, become thermoplastic resins. The resin composition of this embodiment may contain only one type of thermoplastic 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.

[0034] <Talc with a crystalline silica content of less than 0.1% by mass> The resin composition of this embodiment contains talc having a crystalline silica content of less than 0.1% by mass (hereinafter sometimes referred to as "silica-less talc"). By including such silica-less talc, discoloration of the resulting molded product during heating can be effectively suppressed. Traditionally, talc has been added to thermoplastic resins to improve their physical properties. Here, talc is hydrated magnesium silicate (Mg3Si4O 10 It is a clay mineral whose main component is (OH)2), and is known as a clay mineral in which tetrahedral sheets of Si-O tetrahedra and octahedral sheets of Mg-(OH) octahedra are sandwiched together in a 2:1 ratio. [ka]

[0035] However, since talc is usually extracted as a natural mineral, it contains impurities. Specifically, it is known to contain crystalline silica in a proportion of 0.1% by mass or more. In contrast, in this embodiment, by using silica talc, it is possible to sufficiently disperse it in the resin composition, maintain its color even when the molded product is heated, and effectively suppress discoloration caused by burning during heating. Crystalline silica is composed of SiO4 tetrahedra bonded together in a periodic, regular pattern. It exists in various crystalline forms, including quartz, cristobalite, and tridymite, and is commonly identified by X-ray diffraction analysis. Specifically, each crystalline form can be distinguished from the angle of the diffraction line peaks that appear at approximately 2θ = 19-30°. The crystalline silica content is generally calculated from the characteristic peak intensities of each polymorph in XRD measurements.

[0036] Silica-less talc has a crystalline silica content of 0% by mass or more and less than 0.1% by mass. Conventionally, talc blended into crystalline thermoplastic resins contained crystalline silica at a ratio of 0.1% by mass or more. In this embodiment, by using silica-less talc with a crystalline silica content of less than 0.1% by mass, discoloration during heating was suppressed.

[0037] The number-average particle size (D50) of silica starc is preferably 0.1 μm or more, more preferably 1 μm or more, even more preferably 3 μm or more, preferably 30 μm or less, more preferably 20 μm or less, and even more preferably 15 μm or less. By setting it above the lower limit, the effect as a crystal nucleating agent can be effectively exerted. Furthermore, by setting it below the upper limit, the decrease in the tensile nominal strain of the molded product can be suppressed. If two or more types of silica talc are included, the number-average particle size (D50) of the mixture is used. Silica-free talc can also be commercially available, such as those manufactured by Nippon Talc, with product names "P-3-SF", "K1#90-SF", "MS-SF", "FG-20F", "FG-15F", "NanoAce D-1000F", "NanoAce D-800F", and "NanoAce D-600F".

[0038] On the other hand, another example of silica starc is plant-derived silica, with rice husk-derived silica being preferred. Plant-derived silica can be commercially available, such as "rice husk-derived silica" manufactured by MIT Corporation.

[0039] The silica talc content in the resin composition of this embodiment is 0.01 parts by mass or more, preferably 0.05 parts by mass or more, more preferably 0.08 parts by mass or more, even more preferably 0.1 parts by mass or more, even more preferably 0.2 parts by mass or more, even more preferably 0.3 parts by mass or more, and also 30 parts by mass or less, preferably 10 parts by mass or less, more preferably 5.0 parts by mass or less, even more preferably 2.5 parts by mass or less, even more preferably 1.5 parts by mass or less, and even more preferably 1.0 part by mass or less. Setting the content above the lower limit tends to improve moldability. Furthermore, setting the content below the upper limit can more effectively suppress the decrease in tensile strain of the resulting molded product and suppress the decrease in the physical properties of the resin composition. The resin composition of the present embodiment may contain only one type or two or more types of silica-free talc, respectively. When two or more types are contained, the total amount is preferably within the above range.

[0040] The resin composition of the present embodiment may or may not contain talc other than silica-free talc. Specifically, the content of talc other than silica-free talc contained in the resin composition is preferably less than 10% by mass of the content of silica-free talc, more preferably less than 7% by mass, still more preferably less than 5% by mass, even more preferably less than 3% by mass, and may be less than 1% by mass.

[0041] <Epoxy compound having internal epoxide in the molecule> The resin composition of the present embodiment contains an epoxy compound having an internal epoxide in the molecule (internal epoxide-containing epoxy compound). By containing an epoxy compound having an internal epoxide in the molecule such as the compound main chain, the moisture and heat resistance of the obtained molded product can be more effectively improved. The internal epoxide-containing epoxy compound is a compound having structure (A).

Chemical formula

Chemical formula

[0042] 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.

[0043] 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 compound and further improve its basic physical properties. Setting it below the upper limit tends to improve compatibility with thermoplastic resins and further improve its basic physical properties. If the compound represented by formula (A-1) is a mixture, the molecular weight shall be the weighted average value.

[0044] 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 the substituents described in the section of formula (A-1) above are preferred.

[0045] 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. This makes the reaction less likely to proceed, and a sufficient amount of epoxy group can be left in the resulting molded article. As a result, the heat and humidity resistance of the molded article can be improved. In contrast, in the case of compounds having structure (B), the epoxy group is located at the terminal position, so the reaction proceeds easily, and the effect of improving the moisture and heat resistance of the molded product is lower compared to the case of compounds having structure (A).

[0046] 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).

[0047] 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, the epoxidized fatty acid ester is preferably 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, soybean oil and / or linseed oil is more preferred, and linseed oil is even more preferred.

[0048] 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 shall be the weighted average value of the epoxy equivalents of the internal epoxide-containing epoxy compounds.

[0049] 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.

[0050] The content of the internal epoxide-containing epoxy compound in the resin composition of this embodiment is 0.01 parts by mass or more, preferably 0.05 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, even more preferably 1.2 parts by mass or more, and also 30 parts by mass or less, preferably 20 parts by mass or less, more preferably 15 parts by mass or less, even more preferably 10 parts by mass or less, even more preferably 5 parts by mass or less, and even more preferably 2 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 discoloration suppression and bleed-out suppression effect after heating of the molded product. 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.

[0051] <Stabilizer> The resin composition of 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, hindered phenol compounds, and phosphite compounds, with 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.

[0052] 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.

[0053] 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."

[0054] 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. 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.

[0055] 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.

[0056] The stabilizer content in the resin composition of this embodiment is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and even more preferably 0.1 parts by mass or more, per 100 parts by mass of thermoplastic resin. Setting the content above the lower limit tends to further improve the effect of suppressing thermal degradation and oxidative degradation of the resin during melt mixing, molding, and use as a molded product, and tends to improve heat resistance. Furthermore, the upper limit of the stabilizer content is preferably 1.0 part by mass or less, more preferably 0.8 parts by mass or less, more preferably 0.6 parts by mass or less, even more preferably 0.5 parts by mass or less, and even more preferably 0.4 parts by mass or less, per 100 parts by mass of thermoplastic 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.

[0057] <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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] The resin composition of this embodiment preferably contains 0.01 parts by mass or more of a release agent per 100 parts by mass of thermoplastic 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.

[0068] <Other ingredients> The resin composition of 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 not mentioned above. Examples of resin additives include flame retardants, flame retardant enhancers, anti-dripping agents, transesterification inhibitors, UV absorbers, mold release agents, colorants (pigments, dyes), nucleating agents other than talc, antistatic agents, anti-fogging agents, anti-blocking agents, flow improvers, 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, and even more preferably 0% by mass or more and less than 3% by mass, based on 100% by mass of the resin composition. The resin composition of this embodiment comprises a thermoplastic resin, talc with a crystalline silica content of less than 0.1% by mass, an internally epoxide-containing epoxy compound, and other components added as needed, with the total amount being 100% by mass. In this embodiment, the resin composition preferably contains a total of 90% or more by mass of the thermoplastic resin, talc with a crystalline silica content of less than 0.1% by mass, an internally epoxide-containing epoxy compound, and stabilizers and release agents added as needed, and may be 100% by mass.

[0069] <Physical properties of resin compositions> The resin composition of this embodiment preferably has a high tensile strain. Specifically, when the resin composition of this embodiment is molded into an ISO test piece with a thickness of 4 mm, the tensile nominal strain in accordance with ISO 527-1 and ISO 527-2 is preferably 30% or more, more preferably 40% or more, even more preferably 50% or more, and even more preferably 55% or more. The upper limit of the tensile nominal strain is usually 250% or less, and 100% or less is practical. Furthermore, when the resin composition of this embodiment is molded into a 1 mm thick No. 4 dumbbell test piece, it is preferable that the tensile strain at a chuck distance of 85 mm and a tensile speed of 50 mm / min is 18% or more. The upper limit of the tensile strain is usually 100% or less, and 40% or less is practical.

[0070] <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 it and melt-kneaded. The thermoplastic resin used for the masterbatch is preferably a polyalkylene terephthalate resin, more preferably a thermoplastic resin and / or polyethylene terephthalate resin, and even more preferably a thermoplastic resin.

[0071] <Method for manufacturing molded products> The resin composition or pellets of this embodiment are molded according to known methods. The method for manufacturing the molded product is not particularly limited, and any molding method commonly used for 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 a heat-insulating mold, molding using a rapidly heated mold, foam molding (including supercritical fluid), 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 them. Details of the injection molding method can be found in paragraphs 0113 to 0116 of Japanese Patent No. 6183822, and these contents are incorporated herein by reference. Furthermore, the mold temperature during mold molding, such as injection molding, is preferably between 40 and 150°C.

[0072] <Application> The resin composition of this embodiment is used as a molded article formed from the resin composition or pellets. The resin composition and pellets can be widely used in known applications. For example, they can be widely used both indoors and outdoors in electrical and electronic equipment materials, automotive materials, housing materials, and materials for manufacturing parts in other industrial fields. More specifically, examples include circuit breakers, electromagnetic switches, various relay components, transformer components, sensor components, switch components, connector components, terminal components, actuator components, outlet components, socket components, plug components, capacitor components, resistor components, charging components, battery components, housing components, structural components, and insulating components. In particular, it can be suitably used as a material for components located near electrical contacts. Automotive materials include housings, reflectors, bezels, and extensions for lamps, as well as connectors, ECU cases, enclosures for in-vehicle cameras and millimeter-wave radar, battery cases, and sensor enclosures. Examples of electrical and electronic components include various housings, personal computers, game consoles, display devices such as televisions, printers, copiers, scanners, fax machines, electronic organizers and PDAs, electronic desktop calculators, electronic dictionaries, cameras, video cameras, mobile phones, battery packs, drives and readers for recording media, mice, numeric keypads, housings, covers, keyboards, buttons, and switch components for CD players, MD players, portable radios and audio players, power meter housings, battery cases, battery transport trays, relays, sensors, actuators, terminal switches, and components for grill cooking equipment.

[0073] <Method to prevent discoloration> The discoloration suppression method of this embodiment is a method for suppressing discoloration of a molded article formed from a resin composition containing 0.01 to 30 parts by mass of an internal epoxide-containing epoxy compound per 100 parts by mass of a thermoplastic resin, and comprises blending the resin composition with talc having a crystalline silica content of less than 0.1% by mass in a ratio of 0.01 to 30 parts by mass per 100 parts by mass of the thermoplastic resin. Details of the discoloration suppression method can be found in the above description, and preferred ranges, etc., are the same as above. [Examples]

[0074] 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. If the measuring instruments used in the examples are difficult to obtain due to discontinuation or other reasons, measurements can be taken using other instruments with equivalent performance.

[0075] 1.Raw materials The following ingredients were used. [Table 1]

[0076] 2. Examples 1-4, Comparative Examples 1-6 <Compound> Each component shown in Table 1 was uniformly mixed in a tumbler mixer in the proportions shown in Table 2 or Table 3 (each component in Tables 2 and 3 is expressed in parts by mass). The resulting mixture was supplied to a twin-screw extruder (TEX30α, manufactured by Japan Steel Works, Ltd.) through the main feed port. The resin composition was melt-kneaded under the conditions of setting the cylinder temperature of the first kneading section to 260°C and the screw rotation speed to 200 rpm. The mixture was then rapidly cooled in a water bath and pelletized using a pelletizer to obtain pellets of the resin composition.

[0077] <Tensile Nominal Strain (ISO Test Specimen)> The resin pellets obtained above were dried at 120°C for 5 hours, and then ISO multipurpose test specimens (4 mm thick) were injection molded using an injection molding machine (Japan Steel Works, Ltd. "J85AD") under the conditions of a cylinder temperature of 250°C and a mold temperature of 80°C. Using molded multi-purpose ISO test specimens, tensile nominal strain (in %) was measured in accordance with ISO 527-1 and ISO 527-2. Furthermore, a tensile nominal strain (ISO test specimen) of 30% or more was rated as A, and a strain of less than 30% was rated as B.

[0078] <Tensile strain (dumbbell test specimen)> The resin pellets obtained above were dried at 120°C for 5 hours. Then, a No. 4 dumbbell test piece (1 mm thick) was injection molded using an injection molding machine (Japan Steel Works, Ltd. "J50AD") under the conditions of a cylinder temperature of 250°C and a mold temperature of 80°C. Using a molded dumbbell test specimen, tensile strain (in %) was measured at a chuck distance of 85 mm and a tensile speed of 50 mm / min. Furthermore, a tensile strain (dumbbell test specimen) of 18% or more was rated as A, and a strain of less than 18% was rated as B.

[0079] <Discoloration after heat treatment> The resin pellets obtained above were dried at 120°C for 5 hours, and then ISO multipurpose test specimens (4 mm thick) were injection molded using an injection molding machine (Japan Steel Works, Ltd. "J85AD") under the conditions of a cylinder temperature of 250°C and a mold temperature of 80°C. The obtained multipurpose test specimens (4 mm thick) were treated in an oven at a temperature of 150°C for 1000 hours. The presence or absence of discoloration before and after heat treatment was assessed. The assessment was made by five experts, with Comparative Example 1 designated as B, and the decision was made by majority vote. A: Discoloration is suppressed more than in Comparative Example 1. B: Discoloration similar to that of Comparative Example 1 C: More discolored than in Comparative Example 1.

[0080] <Tensile strength and retention rate after moist heat treatment> The resin pellets obtained above were dried at 120°C for 5 hours, and then ISO multipurpose test specimens (4 mm thick) were injection molded using an injection molding machine (Japan Steel Works, Ltd. "J85AD") under the conditions of a cylinder temperature of 250°C and a mold temperature of 80°C. The obtained multipurpose test specimens (4 mm thick) were treated using a pressure cooker tester under the conditions of a temperature of 121°C, relative humidity of 100%, and pressure of 2 atm for 75 hours. The pressure cooker used for testing was the ESPEC EH8-221M.

[0081] For the test specimens before and after the aforementioned moist heat treatment, the tensile strength (unit: MPa) and retention rate (unit: %) were measured at a temperature of 23°C using the above ISO multipurpose test specimen (4 mm thick) in accordance with ISO 527-1 and 527-2. Tensile strength retention rate (%) = (Tensile strength after PCT treatment / Tensile strength before PCT treatment) × 100

[0082] [Table 2]

[0083] [Table 3]

[0084] As is clear from the above results, the molded articles obtained from the resin composition of the present invention exhibited excellent resistance to moisture and heat, and were able to suppress discoloration during heating (Examples 1-4). Furthermore, they exhibited high tensile strain. In contrast, when talc other than silica-less talc was included (Comparative Example 1, Comparative Example 2), or when talc was not included (Comparative Example 5, Comparative Example 6), the degree of discoloration was higher. On the other hand, when no epoxy compound was included (Comparative Example 3), or when an epoxy compound other than an internally epoxide-containing epoxy compound was used (Comparative Example 4), the heat and humidity resistance was inferior. Furthermore, the tensile strain was also relatively low.

[0085] 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.

Claims

1. Per 100 parts by mass of thermoplastic resin, 0.01 to 30 parts by mass of talc having a crystalline silica content of less than 0.1% by mass and A resin composition comprising 0.01 to 30 parts by mass of an epoxy compound having an internal epoxide within its molecule.

2. The resin composition according to claim 1, wherein the thermoplastic resin includes a crystalline resin.

3. The resin composition according to claim 1, wherein the thermoplastic resin comprises a polybutylene terephthalate resin.

4. The resin composition according to claim 1, wherein the thermoplastic resin comprises a polybutylene terephthalate resin having an intrinsic viscosity of 0.70 to 1.30 dL / g.

5. Pellets of the resin composition according to any one of claims 1 to 4.

6. A molded article formed from the resin composition according to any one of claims 1 to 4.

7. A molded article formed from the pellets described in claim 5.

8. A method for suppressing discoloration of a molded article formed from a resin composition containing 0.01 to 30 parts by mass of an epoxy compound having an internal epoxide in its molecule, per 100 parts by mass of a thermoplastic resin, A method for suppressing discoloration, comprising blending the resin composition with talc having a crystalline silica content of less than 0.1% by mass in a ratio of 0.01 to 30 parts by mass per 100 parts by mass of thermoplastic resin.

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