Resin composition, pellet, and molded article

Abstract

To provide a resin composition capable of yielding a molded article with high weld strength, the resin composition comprising a polybutylene terephthalate resin blended with a polystyrene-based resin, and also to provide a pellet, and a molded article.SOLUTION: A resin composition according to the present disclosure comprises a polybutylene terephthalate resin and a polystyrene-based resin, wherein an active titanium parameter X for the polybutylene terephthalate resin, specified herein, is 25 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition, a pellet, and a molded article, and more particularly to a resin composition containing a polybutylene terephthalate resin as a main component. [Background technology]

[0002] Polybutylene terephthalate resin, a representative engineering plastic among thermoplastic polyester resins, is widely used in injection-molded products such as automotive parts, electrical and electronic parts, and precision instrument parts due to its ease of molding and processing, mechanical properties, heat resistance, chemical resistance, aroma retention, and other excellent physical and chemical properties.

[0003] However, because polybutylene terephthalate resin is a crystalline resin, it has a large molding shrinkage rate. In particular, when inorganic fillers such as glass fiber are blended, anisotropy tends to increase, which can lead to warping of molded products. Therefore, methods of blending various amorphous resins have been proposed to reduce warping (Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-16559 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-314619 [Patent Document 3] Japanese Patent Publication No. 2020-84037 Summary of the Invention [Problem to be solved by the invention]

[0005] Here, it has been found that when a polystyrene-based resin is blended with a polybutylene terephthalate resin in order to suppress warpage, the weld strength may decrease. The present invention aims to solve these problems and to provide a resin composition, pellets, and molded articles that can provide molded articles with high weld strength in a resin composition that blends a polybutylene terephthalate resin with a polystyrene-based resin. [Means for solving the problem]

[0006] In light of the above-mentioned problems, the present inventors have conducted research and found that the above-mentioned problems can be solved by using a polybutylene terephthalate resin that satisfies certain conditions and blending a polystyrene-based resin therein. Specifically, the above problems were solved by the following means. [1] A composition containing a polybutylene terephthalate resin and a polystyrene-based resin, The polybutylene terephthalate resin A resin composition having an active titanium parameter X shown below of 25 or less.

number

number

[10] The resin composition according to any one of [1] to [9], wherein the active titanium parameter X is 12 or less.

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

[10] , wherein the polybutylene terephthalate resin has an Mw / Mn ratio of 2.1 or more.

[12] The polybutylene terephthalate resin contains 0.1 to 100 mass ppm of sodium element, the polybutylene terephthalate resin contains 0.1 to 3000 mass ppm of calcium element, The proportion α of active titanium represented by the following formula (3) in the polybutylene terephthalate resin is 0.50 or less, The polybutylene terephthalate resin contains polybutylene terephthalate resin derived from material recycling, The polybutylene terephthalate resin contains two or more polybutylene terephthalate resins having different intrinsic viscosities, The resin composition according to any one of [1] to [1], which is for injection molding. α=X / M...Equation (3) (In formula (3), X is the active titanium parameter, and [M] is the titanium element concentration (ppm by mass) in the polybutylene terephthalate resin.)

[12] The polybutylene terephthalate resin contains 0.1 to 100 mass ppm of sodium element, the polybutylene terephthalate resin contains 0.1 to 3000 mass ppm of calcium element, The proportion α of active titanium represented by the following formula (3) in the polybutylene terephthalate resin is 0.50 or less, The polybutylene terephthalate resin contains polybutylene terephthalate resin derived from material recycling, The polybutylene terephthalate resin contains two or more polybutylene terephthalate resins having different intrinsic viscosities, For injection molding, The polybutylene terephthalate resin has a terminal carboxyl group concentration of 25 μmol / g or more, The active titanium parameter X is 12 or less, The resin composition according to any one of [1] to

[11] , wherein the polybutylene terephthalate resin has an Mw / Mn of 2.1 or more. α=X / M...Equation (3) (In formula (3), X is the active titanium parameter, and [M] is the titanium element concentration (ppm by mass) in the polybutylene terephthalate resin.)

[13] Pellets of the resin composition according to any one of [1] to

[12] .

[14] A molded article formed from the resin composition according to any one of [1] to

[12] .

[15] A molded article formed from the pellets according to

[13] . [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a resin composition in which a polybutylene terephthalate resin is blended with a polystyrene-based resin, which is capable of providing a molded article with high weld strength, as well as pellets and molded articles. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment for carrying out the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. Note that the present embodiment is an example for explaining the present invention, and the present invention is not limited to only this embodiment. In this specification, the symbol "to" is used to mean that the numerical values ​​before and after it are included as upper and lower limits. "A to B" means that the range is A or more and B or less. In addition, any combination of the upper and lower limit values ​​of the numerical values ​​in this specification is an example of this embodiment.

[0009] In this specification, various physical properties and characteristic values ​​are those at 23°C unless otherwise specified. In this specification, ppm means ppm by mass. If the measurement methods, etc. described in the standards shown in this specification change from year to year, they will be based on the standards in effect as of January 1, 2024, unless otherwise specified. If the measurement methods, etc. described in the standards shown in this specification are abolished as of January 1, 2024, they will be based on the standards in effect at the time of abolition.

[0010] The resin composition of this embodiment contains a polybutylene terephthalate resin and a polystyrene-based resin, and is characterized in that the polybutylene terephthalate resin has an active titanium parameter X shown below of not more than 25. The resin composition of this embodiment preferably contains 30 to 500 ppm by mass of titanium element.

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number

[0011] By adopting such a constitution, a resin composition capable of providing a molded product with high weld strength can be obtained. In order to achieve low warpage in molded articles formed from polybutylene terephthalate resin, it has been considered to blend a polystyrene-based resin, but blending a polystyrene-based resin with polybutylene terephthalate resin tends to reduce weld strength. Under these circumstances, the present inventors have discovered the use of polybutylene terephthalate resins with low titanium activity. Specifically, when producing polybutylene terephthalate resins, butylene glycol and terephthalic acid are typically reacted in the presence of a titanium catalyst. However, even in the produced polybutylene terephthalate resins, high titanium activity can easily generate tetrahydrofuran gas derived from butanediol terminals. It is believed that molding a resin composition containing a large amount of such tetrahydrofuran gas can easily clog voids at the flow end of the mold, resulting in reduced weld strength. In this embodiment, it is believed that the combined use of a polybutylene terephthalate resin with low titanium activity and a polystyrene-based resin effectively suppresses the generation of tetrahydrofuran gas derived from butanediol, thereby improving weld strength. In particular, as shown in the examples described below, a surprising increase in weld strength of approximately 20% was observed in the present invention.

[0012] Hereinafter, the embodiments of the present invention will be described in detail. However, the explanation of the constituent elements described below is an example of an embodiment of the present invention, and the present invention is not limited to these contents.

[0013] <Polybutylene terephthalate resin> The resin composition of the present embodiment contains a polybutylene terephthalate resin having an active titanium parameter X shown below of not more than 25. The resin composition preferably contains 30 to 500 ppm by mass of titanium element.

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number

[0014] Titanium catalysts are commonly used in the synthesis of polybutylene terephthalate resins. However, it has been found that high titanium catalyst activity in the polymerized polybutylene terephthalate resin tends to generate tetrahydrofuran derived from butanediol. In particular, in industrial mass production, extrusion is carried out continuously for a long period of time using a large extruder, and in such cases, tetrahydrofuran tends to be generated more easily. In this embodiment, it is presumed that the use of a polybutylene terephthalate resin with low titanium activity effectively suppressed the generation of tetrahydrofuran gas in the molded product, thereby improving the weld strength.

[0015] The active titanium parameter X of the polybutylene terephthalate resin used in this embodiment is 25 or less, preferably 20 or less, more preferably 15 or less, even more preferably 12 or less, and still more preferably 10 or less. The lower limit of the active titanium parameter X of the polybutylene terephthalate resin is preferably 0, but even if it is 1 or more, the required performance is sufficiently satisfied. When two or more polybutylene terephthalate resins are used, it is preferable that the polybutylene terephthalate resin with the largest content satisfies the above active titanium parameters, and it is more preferable that all of the polybutylene terephthalate resins satisfy the above active titanium parameters.

[0016] A polybutylene terephthalate resin synthesized using a titanium catalyst and having a low active titanium parameter X can be obtained, for example, by the following method. (1) Increasing the concentration of metal elements such as sodium and calcium in the polybutylene terephthalate resin. These metal elements tend to reduce the activity of the titanium catalyst. (2) Increase the amount of alkaline components in the polybutylene terephthalate resin. Titanium catalysts are acid catalysts, so their activity tends to decrease in the presence of alkaline components. (3) Increasing the terminal carboxylic acid concentration of the polybutylene terephthalate resin. (4) Use recycled polybutylene terephthalate resin. In particular, recycled polybutylene terephthalate resin tends to have low titanium catalyst activity. α=X / M...Equation (3) (In formula (3), X is the active titanium parameter, and [M] is the titanium element concentration (ppm by mass) in the polybutylene terephthalate resin.)

[0017] The evaluation of the change in terminal carboxyl group concentration over time is performed in a nitrogen atmosphere to prevent the influence of oxygen. Furthermore, if the water concentration in the polybutylene terephthalate resin being evaluated is high, hydrolysis reactions occur frequently, making it difficult to accurately understand the decomposition behavior associated with catalytic activity other than hydrolysis. Therefore, a low water concentration of 300 mass ppm or less is preferable. The evaluation is performed at a temperature of 245°C. Under these heat treatment conditions, the decrease in number average molecular weight due to reactions other than hydrolysis caused by the water contained in the polybutylene terephthalate resin can be ignored. The increase in terminal carboxyl group concentration due to hydrolysis reactions can be considered equal to the increase in terminal hydroxyl group concentration before and after heat treatment. Therefore, the change in terminal carboxyl group concentration due to thermal decomposition reactions other than hydrolysis reactions can be calculated using the following equation (4).

[0018] Formula (4)

number

[0019] The titanium element concentration in the polybutylene terephthalate resin used in the present embodiment is preferably 30 ppm by mass or more, and may be 35 ppm by mass or more, 40 ppm by mass or more, 45 ppm by mass or more, 50 ppm by mass or more, 55 ppm by mass or more, 60 ppm by mass or more, 65 ppm by mass or more, 70 ppm by mass or more, or 75 ppm by mass or more, and may be 500 ppm by mass or less, 400 ppm by mass or less, 300 ppm by mass or less, 150 ppm by mass or less, 120 ppm by mass or less, 110 ppm by mass or less, 100 ppm by mass or less, 90 ppm by mass or less, or 80 ppm by mass or less.

[0020] The sodium element concentration in the polybutylene terephthalate resin used in this embodiment is preferably 0.1 parts by mass or more, more preferably 0.5 ppm by mass or more, even more preferably 0.7 ppm by mass or more, even more preferably 0.9 ppm by mass or more, and even more preferably 1 ppm by mass or more, and is preferably 100 ppm by mass or less, more preferably 50 ppm by mass or less, even more preferably 30 ppm by mass or less, even more preferably 20 ppm by mass or less, and even more preferably 10 ppm by mass or less. By setting the sodium element concentration at or above the lower limit, the generation of tetrahydrofuran gas tends to be more effectively suppressed. Meanwhile, by setting the sodium element concentration at or below the upper limit, the alkali decomposition resistance tends to be further improved. The sodium element in the polybutylene terephthalate resin comes from, for example, the detergent used in the resin washing process.

[0021] The calcium element concentration of the polybutylene terephthalate resin used in this embodiment is preferably 0.1 ppm by mass or more, more preferably 1 ppm by mass or more, even more preferably 3 ppm by mass or more, even more preferably 5 ppm by mass or more, and even more preferably 7 ppm by mass or more. It is also preferably 3000 ppm by mass or less, more preferably 2500 ppm by mass or less, preferably 2000 ppm by mass or less, and preferably 1500 ppm by mass or less, and even more preferably 1000 ppm by mass or less, more preferably 500 ppm by mass or less, even more preferably 300 ppm by mass or less, and even more preferably 200 ppm by mass or less, and may be 100 ppm by mass or less, 50 ppm by mass or less, 30 ppm by mass or less, or 10 ppm by mass or less. By setting the calcium element concentration at or above the lower limit, the generation of tetrahydrofuran gas tends to be more effectively suppressed. By setting the calcium element concentration at or below the upper limit, the alkali decomposition resistance tends to be further improved. The calcium element in the polybutylene terephthalate resin is derived from, for example, the inorganic filler of the inorganic filler.

[0022] The titanium element concentration, sodium element concentration, and calcium element concentration are measured according to the description in the Examples section below.

[0023] The polybutylene terephthalate resin used in this embodiment preferably has an active titanium content α of 0.50 or less, as represented by formula (3). By setting the active titanium content α to 0.50 or less, the generation of tetrahydrofuran gas tends to be more effectively suppressed. α=X / M...Equation (3) (In formula (3), X is the active titanium parameter, and [M] is the titanium element concentration (ppm by mass) in the polybutylene terephthalate resin.) The active titanium ratio α is preferably 0.45 or less, more preferably 0.40 or less, even more preferably 0.35 or less, even more preferably 0.30 or less, even more preferably 0.25 or less, even more preferably 0.20 or less, and even more preferably 0.15 or less. The lower limit of the active titanium ratio α is preferably 0, but even if it is 0.01 or more, the required performance is sufficiently met.

[0024] The intrinsic viscosity of the polybutylene terephthalate resin is preferably 0.60 dL / g or more, more preferably 0.75 dL / g or more, even more preferably 0.80 dL / g or more, and even more preferably 0.85 dL / g or more. By setting it to the lower limit or more, deterioration of physical properties such as strength tends to be effectively suppressed. Furthermore, the intrinsic viscosity of the polybutylene terephthalate resin is preferably 1.30 dL / g or less, more preferably 1.10 dL / g or less, even more preferably 1.00 dL / g or less, and even more preferably 0.90 dL / g or less. By setting it to the upper limit or less, deterioration of fluidity tends to be effectively suppressed. In this embodiment, two or more polybutylene terephthalate resins having different intrinsic viscosities may be used. For example, a polybutylene terephthalate resin having an intrinsic viscosity of 0.60 to 0.75 dL / g and a polybutylene terephthalate resin having an intrinsic viscosity of more than 0.75 dL / g but not more than 0.95 dL / g may be blended in a mass ratio of 1-10:99-90. This composition tends to increase the deflection temperature under load of the resulting molded article. The intrinsic viscosity is measured as described in the Examples section below.

[0025] In the resin composition of this embodiment, the terminal carboxyl group concentration (acid value) of the polybutylene terephthalate resin is preferably 100 μmol / g or less (μeq / g), more preferably 80 μmol / g or less, more preferably 70 μmol / g or less, even more preferably 60 μmol / g or less, even more preferably 40 μmol / g or less, even more preferably 30 μmol / g or less, and preferably 10 μmol / g or more, more preferably 20 μmol / g or more, even more preferably 25 μmol / g or more, and even more preferably 27 μmol / g or more. By setting it to the above upper limit or less, excellent hydrolysis resistance tends to be achieved. Furthermore, by setting it to the above lower limit or more, adhesive strength to adhesives tends to be further improved. When the resin composition of the present embodiment contains two or more types of polybutylene terephthalate resins, the terminal carboxyl group concentration of the mixture preferably falls within the above range. The terminal carboxyl group concentration of the polybutylene terephthalate resin is measured according to the description in the Examples section below. A polybutylene terephthalate resin having such a concentration of terminal carboxyl groups can be obtained by, for example, subjecting it to a thermal history of a temperature equal to or higher than the melting point, such as by melt-kneading.

[0026] In the resin composition of this embodiment, the terminal hydroxy group concentration of the polybutylene terephthalate resin is preferably 110 μmol / g or less, more preferably 100 μmol / g or less, and even more preferably 95 μmol / g or less, and is preferably 30 μmol / g or more, more preferably 35 μmol / g or more, even more preferably 40 μmol / g or more, even more preferably 50 μmol / g or more, and even more preferably 70 μmol / g or more. By setting the concentration below the upper limit, transesterification reactions are suppressed during melt-kneading with other resins such as polycarbonate, thereby shortening the molding cycle. Furthermore, by setting the concentration above the lower limit, adhesive strength to adhesives tends to be further improved.

[0027] When the resin composition of the present embodiment contains two or more types of polybutylene terephthalate resins, the terminal hydroxy group concentration of the mixture preferably falls within the above range. The terminal hydroxyl group concentration of the polybutylene terephthalate resin is measured according to the description in the Examples section below. A polybutylene terephthalate resin having such a concentration of terminal hydroxy groups can be obtained by, for example, subjecting it to a heat history of a temperature equal to or higher than the melting point, such as by melt-kneading.

[0028] The terminal vinyl group concentration of the polybutylene terephthalate resin is preferably 50 μmol / g or less, more preferably 15 μmol / g or less, even more preferably 12 μmol / g or less, even more preferably 10 μmol / g or less, even more preferably 8 μmol / g or less, and preferably 1 μmol / g or more, more preferably 2 μmol / g or more, and even more preferably 3 μmol / g or more. By setting the concentration below the upper limit, the terminal hydroxyl group concentration and terminal carboxyl group concentration become relatively high, which tends to further improve adhesion to epoxy adhesives. On the other hand, by setting the concentration above the lower limit, the terminal hydroxyl group concentration and terminal carboxyl group concentration become relatively low, which suppresses reactivity with other resins such as polycarbonate and epoxy resin, reduces the thickening effect, and tends to improve fluidity. When the resin composition of the present embodiment contains two or more types of polybutylene terephthalate resins, the terminal vinyl group concentration of the mixture preferably falls within the above range. The terminal vinyl group concentration of the polybutylene terephthalate resin is measured according to the description in the Examples section below. A polybutylene terephthalate resin having such a concentration of terminal vinyl groups can be obtained by increasing the number of times the polybutylene terephthalate resin is subjected to heat history, for example, by increasing the number of times it is melt-kneaded.

[0029] The polybutylene terephthalate resin used in the resin composition of this embodiment is a polyester resin having a structure in which terephthalic acid units and 1,4-butanediol units are ester-bonded, and includes not only polybutylene terephthalate resin (homopolymer), but also polybutylene terephthalate copolymers containing other copolymerization components other than terephthalic acid units and 1,4-butanediol units, and mixtures of homopolymers and polybutylene terephthalate copolymers.

[0030] The polybutylene terephthalate resin may contain one or more dicarboxylic acid units other than terephthalic acid. Specific examples of other dicarboxylic acids include aromatic dicarboxylic acids 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, bis(4,4'-carboxyphenyl)methane, anthracenedicarboxylic acid, and 4,4'-diphenyletherdicarboxylic acid; alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid and 4,4'-dicyclohexyldicarboxylic acid; and aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, and dimer acid. In the polybutylene terephthalate resin used in this embodiment, terephthalic acid units preferably account for 80 mol % or more of all dicarboxylic acid units, more preferably 90 mol % or more, even more preferably 95 mol % or more, and may even account for 99 mol % or more.

[0031] The diol unit may contain one or more other diol units in addition to 1,4-butanediol. Specific examples of other diol units include aliphatic or alicyclic diols having 2 to 20 carbon atoms, bisphenol derivatives, etc. Specific examples include ethylene glycol, propylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, decamethylene glycol, cyclohexanedimethanol, 4,4'-dicyclohexylhydroxymethane, 4,4'-dicyclohexylhydroxypropane, and ethylene oxide adduct diol of bisphenol A. In addition to the above-mentioned bifunctional monomers, small amounts of trifunctional monomers such as trimellitic acid, trimesic acid, pyromellitic acid, pentaerythritol, and trimethylolpropane can also be used in combination to introduce a branched structure, or monofunctional compounds such as fatty acids can be used in combination to adjust the molecular weight. In the polybutylene terephthalate resin used in this embodiment, 1,4-butanediol units preferably account for 80 mol% or more of all diol units, more preferably 90 mol% or more, even more preferably 95 mol% or more, and may even account for 99 mol% or more.

[0032] As described above, the polybutylene terephthalate resin is preferably a polybutylene terephthalate homopolymer obtained by polycondensation of terephthalic acid and 1,4-butanediol. Alternatively, the polybutylene terephthalate copolymer may contain, as the carboxylic acid unit, one or more dicarboxylic acids other than the terephthalic acid and / or, as the diol unit, one or more diols other than the 1,4-butanediol. When the polybutylene terephthalate resin is a polybutylene terephthalate resin modified by copolymerization, 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. Among these, polyester ether resins copolymerized with polytetramethylene glycol are preferred. When the polybutylene terephthalate resin is a copolymer, the copolymerization amount is 1 mol% or more and less than 50 mol% of all polybutylene terephthalate resin units. In particular, the copolymerization amount is preferably 2 mol% or more and less than 50 mol%, more preferably 3 to 40 mol%, and even more preferably 5 to 20 mol%. By setting the copolymerization amount in this range, molded articles with small molding shrinkage and high impact resistance can be obtained, which is preferable.

[0033] The polybutylene terephthalate resin used in this embodiment preferably has a high degree of dispersion. A high degree of dispersion increases the amount of terminal groups (particularly the amount of terminal hydroxyl groups and / or the amount of terminal carboxyl groups) in the polybutylene terephthalate resin, thereby further improving adhesion to an epoxy adhesive.

[0034] The polybutylene terephthalate resin preferably has an Mw / Mn of 2.1 or more, more preferably 2.2 or more, and even more preferably 2.3 or more, and preferably 3.5 or less, more preferably 3.0 or less, even more preferably 2.7 or less, even more preferably 2.6 or less, and even more preferably 2.5 or less. By making the Mw / Mn ratio equal to or greater than the lower limit, the adhesive strength to epoxy adhesives tends to be further improved. On the other hand, by making the Mw / Mn ratio equal to or less than the upper limit, the mechanical strength tends to be further improved. Such a polybutylene terephthalate resin with a high degree of dispersion can be obtained by increasing the number of times the polybutylene terephthalate resin is subjected to thermal history, for example, by increasing the number of times it is melt-kneaded, or by blending two or more polybutylene terephthalate resins with different average molecular weights.

[0035] The number average molecular weight (Mn) of the polybutylene terephthalate resin used in this embodiment is preferably 2500 or more, more preferably 3000 or more, even more preferably 3500 or more, even more preferably 3700 or more, and even more preferably 4000 or more, and is preferably 20000 or less, more preferably 18000 or less, even more preferably 14000 or less, even more preferably 10000 or less, and even more preferably 6000 or less. By setting it to be equal to or greater than the lower limit, mechanical strength tends to be excellent. On the other hand, by setting it to be equal to or less than the upper limit, the fluidity of the resin tends to be improved.

[0036] The weight average molecular weight (Mw) of the polybutylene terephthalate resin used in this embodiment is preferably 5000 or more, more preferably 6000 or more, even more preferably 7000 or more, even more preferably 8000 or more, and even more preferably 9500 or more, and is preferably 40000 or less, more preferably 35000 or less, even more preferably 30000 or less, even more preferably 25000 or less, and even more preferably 20000 or less. By setting it to be equal to or greater than the lower limit, mechanical strength tends to be further improved. On the other hand, by setting it to be equal to or less than the upper limit, the fluidity of the resin tends to be improved.

[0037] The number average molecular weight and weight average molecular weight of the polybutylene terephthalate resin are measured by the following method.

[0038] <Weight average molecular weight (Mw) and number average molecular weight (Mn)> Using a Tosoh HLC-8320, polybutylene terephthalate resin was weighed, and a predetermined amount of HFIP (hexafluoro-2-propanol) and 10 mM CF3COONa eluent was added. The resin was allowed to dissolve overnight at room temperature. The sample was then filtered through a 0.45 μm PTFE cartridge filter. The molecular weight (Mw, Mn) of the dissolved sample (filtrate) was measured by GPC. The calibration curve was a cubic approximation curve using standard PMMA, and the molecular weight was expressed in terms of PMMA. For the measurement by GPC, a Tosoh TSKgel GMHhr-M column (manufactured by Tosoh) can be used.

[0039] The melting point (Tm) of the polybutylene terephthalate resin used in this embodiment, measured by DSC, is preferably 200°C or higher, more preferably 205°C or higher, even more preferably 210°C or higher, even more preferably 215°C or higher, and even more preferably 220°C or higher, and is preferably 280°C or lower, more preferably 270°C or lower, even more preferably 260°C or lower, even more preferably 255°C or lower, and even more preferably 240°C or lower. By setting the melting point at or above the lower limit, heat resistance tends to be further improved. Meanwhile, by setting the melting point at or below the upper limit, molding cycle tends to be further improved. When the resin composition of this embodiment contains two or more polyalkylene terephthalate resins, the melting point is the melting point of the mixture. When multiple melting point peaks are detected, it is sufficient that at least one of the multiple melting points falls within the range from the lower limit to the upper limit. However, it is preferable that the component with the highest content among the multiple melting points falls within the range from the lower limit to the upper limit, and it is more preferable that all of the multiple melting points fall within the range from the lower limit to the upper limit.

[0040] The crystallization temperature (Tc) of the polybutylene terephthalate resin used in this embodiment, measured by DSC, is preferably 130°C or higher, more preferably 145°C or higher, even more preferably 160°C or higher, even more preferably 175°C or higher, even more preferably 190°C or higher, and is preferably 240°C or lower, more preferably 230°C or lower, even more preferably 220°C or lower, even more preferably 210°C or lower, and even more preferably 200°C or lower. By setting it to be equal to or higher than the lower limit, the solidification rate tends to be improved and the molding cycle tends to be further improved. Furthermore, by setting it to be equal to or lower than the upper limit, the appearance of the molded article tends to be improved. When the resin composition of this embodiment contains two or more polyalkylene terephthalate resins, the crystallization temperature is the crystallization temperature of the mixture. When multiple crystallization temperature peaks are detected, it is sufficient that at least one of the multiple crystallization temperatures falls within the range from the lower limit to the upper limit. However, it is preferable that the component with the highest content among the multiple crystallization temperatures falls within the range from the lower limit to the upper limit, and it is more preferable that all of the multiple crystallization temperatures fall within the range from the lower limit to the upper limit. The Tm and Tc of the polyalkylene terephthalate resin are measured by the following method.

[0041] <Melting point (Tm) and crystallization temperature (Tc)> The melting point (Tm) and crystallization temperature (Tc) of polybutylene terephthalate resin are measured using a differential scanning calorimeter (DSC) in accordance with JIS K7121. The temperature is raised from 40°C to 300°C at a rate of 20°C / min in a nitrogen atmosphere, held at 300°C for 3 minutes, and then lowered to 40°C at a rate of -20°C / min. This constitutes one cycle. The temperature of the maximum peak due to crystallization during cooling is taken as the crystallization temperature Tc. The melting point Tm is calculated from the peak value during melting. The units are °C. The differential scanning calorimeter that can be used is "DSC7020" manufactured by Hitachi High-Tech Science Corporation.

[0042] In particular, the polybutylene terephthalate resin used in this embodiment has dicarboxylic acid units and diol units, and it is preferred that 80 mol% or more (preferably 90 mol% or more, more preferably 95 mol% or more, and even more preferably 99 mol% or more) of all dicarboxylic acid units are terephthalic acid units derived from fossil resources, and 80 mol% or more (preferably 90 mol% or more, more preferably 95 mol% or more, and even more preferably 99 mol% or more) of all diol units are 1,4-butanediol units derived from fossil resources. The polybutylene terephthalate resin used in this embodiment is preferably not a bio-based polybutylene terephthalate resin. An example of a bio-based polybutylene terephthalate resin is a polybutylene terephthalate resin in which 10% by mass or more, or even 30% by mass or more, or 90% by mass or less, or even 60% by mass or less of the total amount of dicarboxylic acids and diols, which are raw materials for the polybutylene terephthalate resin, are bio-based raw materials.

[0043] The polybutylene terephthalate resin used in this embodiment may be a recycled product. Examples of recycled polybutylene terephthalate resin include those obtained by material recycling in which molded articles of recovered used polybutylene terephthalate resin are crushed, washed, and reused, and those obtained by chemical recycling (chemical decomposition method). In this embodiment, it is preferable to include polybutylene terephthalate resin derived from material recycling. Polybutylene terephthalate resin derived from material recycling may be contaminated with alkaline components during use as a product or during the cleaning process during recycling. It is presumed that the contamination of such alkaline components into polybutylene terephthalate resin reduces the titanium catalyst activity in the polybutylene terephthalate resin. In this embodiment, recycled polybutylene terephthalate resins that have undergone a large number of thermal histories can be used. Examples of thermal histories include melt-kneading, and thermoforming such as injection molding and extrusion molding. In this embodiment, polybutylene terephthalate resins that have undergone 3 to 10 thermal histories can be used. Examples of such recycled products include connectors, home appliances, toothbrushes, fibers, miscellaneous goods, automobile parts, films, tubes, and other extruded parts.

[0044] The content of polybutylene terephthalate resin in the resin composition of this embodiment is preferably 30% by mass or more, more preferably 35% by mass or more, even more preferably 40% by mass or more, and even more preferably 45% by mass or more, based on 100% by mass of the resin composition. It is also preferably 60% by mass or less, more preferably 55% by mass or less, and even more preferably 50% by mass or less. By setting the content at or above the lower limit, the heat resistance of the resulting molded article tends to be improved. Furthermore, by setting the content at or below the upper limit, the shrinkage rate of the resulting molded article tends to be reduced. The resin composition of the present embodiment may contain only one type of polybutylene terephthalate resin, or may contain two or more types. When two or more types are contained, the total amount is preferably in the above range.

[0045] <Polystyrene resin> The resin composition of the present embodiment contains a polystyrene-based resin, which makes it possible to effectively suppress warpage of the resulting molded article. The polystyrene resin in this embodiment may be a homopolymer of a styrene monomer, a copolymer of a styrene monomer and a monomer copolymerizable with the styrene monomer, etc. In the copolymer of a styrene monomer and a monomer copolymerizable with the styrene monomer, the styrene monomer preferably accounts for 50% by mass or more of the total monomers, more preferably 60% by mass or more, and preferably 100% by mass or less.

[0046] The styrene-based monomer means styrene and styrene having a substituent, and examples thereof include styrene, α-methylstyrene, p-methylstyrene, vinylxylene, ethylstyrene, dimethylstyrene, p-tert-butylstyrene, vinylnaphthalene, methoxystyrene, monobromostyrene, dibromostyrene, fluorostyrene, and tribromostyrene, with styrene and α-methylstyrene being more preferred, and styrene being particularly preferred. Furthermore, among the monomers constituting the polystyrene-based resin, examples of monomers other than styrene-based monomers include (meth)acrylic acid ester-based monomers, maleimide-based monomers such as maleimide, N-methylmaleimide, and N-phenylmaleimide, α,β-unsaturated carboxylic acids and anhydrides thereof such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, phthalic acid, and itaconic acid, and rubbers such as butadiene.

[0047] The polystyrene resin used in this embodiment may contain a rubber-reinforced polystyrene resin. Specific examples of the rubber-reinforced polystyrene resin 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), and styrene-IPN type rubber copolymer.

[0048] The polystyrene resin used in this embodiment preferably contains 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 molded article can be increased.

[0049] 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 includes high impact polystyrene resin (HIPS). Furthermore, from the viewpoint of heat resistance, polystyrene resin (GPPS) and acrylonitrile-styrene copolymer (AS resin) are more preferable, and polystyrene resin (GPPS) is even more preferable.

[0050] The polystyrene resin used in this embodiment may contain recycled products. Examples of recycled polystyrene resins include those obtained through material recycling, in which scraps or rejected products from molded products, or recovered used polystyrene resin molded products are crushed, washed, and reused, and those obtained through chemical recycling (chemical decomposition method).

[0051] The content of the polystyrene-based resin in the resin composition of this embodiment is preferably 30 parts by mass or more, more preferably 35 parts by mass or more, even more preferably 40 parts by mass or more, even more preferably 45 parts by mass or more, still more preferably more than 50 parts by mass, and 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 the total of the polybutylene terephthalate resin and the polystyrene-based resin. By setting the content at or above the lower limit, the shrinkage rate of the molded article tends to be reduced. Furthermore, by setting the content at or below the upper limit, the heat resistance of the molded article tends to be further improved. The resin composition of the present embodiment may contain only one type of polystyrene resin, or may contain two or more types. When two or more types are contained, the total amount is preferably in the above range.

[0052] <Polycarbonate resin> The resin composition of this embodiment may contain a polycarbonate resin, which serves as a compatibilizer for the polybutylene terephthalate resin and the polystyrene-based resin. Polycarbonate resins are thermoplastic polymers or copolymers which may be branched and are obtained by reacting a dihydroxy compound or a dihydroxy compound together with a small amount of a polyhydroxy compound with phosgene or a carbonic acid diester.

[0053] The dihydroxy compound used as the raw material is preferably an aromatic dihydroxy compound. Specific examples include 2,2-bis(4-hydroxyphenyl)propane (i.e., bisphenol A), 4,4'-isopropylidenebis(2-methylphenol) (i.e., bisphenol C), tetramethylbisphenol A, bis(4-hydroxyphenyl)-p-diisopropylbenzene, hydroquinone, resorcinol, and 4,4-dihydroxydiphenyl, with bisphenol A being preferred. Compounds in which one or more tetraalkylphosphonium sulfonates are bonded to the above aromatic dihydroxy compounds can also be used. The polycarbonate resin used in the present embodiment preferably contains 90% by mass or more (preferably 95% by mass or more) of its structural units derived from aromatic hydroxy compounds, more preferably structural units derived from bisphenol A and / or bisphenol C, and even more preferably structural units derived from bisphenol A.

[0054] To adjust the molecular weight of the polycarbonate resin, a monovalent aromatic hydroxy compound may be used, such as m- and p-methylphenol, m- and p-propylphenol, p-tert-butylphenol, and p-long-chain alkyl-substituted phenol.

[0055] The viscosity average molecular weight (Mv) of the polycarbonate resin is preferably 10,000 or more, more preferably 12,000 or more, even more preferably 13,000 or more, and particularly preferably more than 14,000. If a viscosity average molecular weight lower than 10,000 is used, the resulting resin composition is likely to have low mechanical strength such as impact resistance. Furthermore, Mv is preferably 60,000 or less, more preferably 40,000 or less, even more preferably 35,000 or less, even more preferably 30,000 or less, and may be 25,000 or less, or 20,000 or less. If it is higher than 60,000, the flowability of the resin composition may be poor, resulting in poor moldability.

[0056] In the present invention, the viscosity average molecular weight (Mv) of a polycarbonate resin is a value calculated from the intrinsic viscosity ([η]) obtained by measuring the viscosity of a methylene chloride solution of the polycarbonate resin at 25°C using an Ubbelohde viscometer, and then using the following Schnell viscosity formula: [η]=1.23×10 -4 Mv 0.83

[0057] The melt mass flow rate (MFR) of the 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, and is preferably 100 g / 10 min or less, 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 more effectively exhibited.

[0058] The melt volume rate (MVR) of polycarbonate resin measured in accordance with JIS K7210 (temperature 300°C, load 1.20 kgf) is 0.5 to 20 cm 3 g / 10 min is preferable, and 1 to 10 cm 3 When the MVR is within the above range, the effects of the present invention tend to be more effectively exhibited.

[0059] The method for producing the polycarbonate resin is not particularly limited, and polycarbonate resins produced by either the phosgene method (interfacial polymerization method) or the melt method (ester interchange method) can be used. Also preferred is a polycarbonate resin produced by the melt method and then subjected to post-treatment to adjust the amount of terminal OH groups.

[0060] The polycarbonate resin may be a recycled polycarbonate resin. Examples of recycled polycarbonate resin include those obtained by material recycling, in which recovered used polycarbonate resin molded products are crushed, washed, and reused, those obtained by chemical recycling (chemical decomposition method), and those obtained by mechanical recycling. Chemical recycling involves chemically decomposing recovered used polycarbonate resin molded articles, returning them to their raw material level, and resynthesizing the polycarbonate resin.Mechanical recycling, on the other hand, is a method that makes it possible to remove dirt from polycarbonate resin molded articles more reliably than material recycling by carrying out alkaline washing more rigorously than in the material recycling described above, or by vacuum drying at high temperatures. For example, recycled polycarbonate resin can be obtained from used polycarbonate resin molded products by removing foreign matter, crushing and cleaning the product, and then pelletizing the product using an extruder.

[0061] The content of the polycarbonate resin in the resin composition of this embodiment is preferably 5 parts by mass or more, more preferably 7 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of the total of the polybutylene terephthalate resin and the polystyrene-based resin, and is preferably 25 parts by mass or less, and more preferably 20 parts by mass or less. By ensuring that the content is equal to or greater than the lower limit, the mechanical properties such as tensile strength of the molded article tend to be further improved. Furthermore, by ensuring that the content is equal to or less than the upper limit, the heat resistance of the molded article tends to be further improved. The resin composition of the present embodiment may contain only one type of polycarbonate resin, or may contain two or more types. When two or more types are contained, the total amount is preferably in the above range.

[0062] A first example of a preferred blend form of thermoplastic resins in this embodiment is a resin composition in which polybutylene terephthalate resin and polystyrene-based resin account for 90% by mass or more (preferably 95% by mass or more, and preferably 100% by mass or less) of the thermoplastic resins contained in the resin composition. A second example of a preferred blend form of thermoplastic resins in this embodiment is a resin composition in which polybutylene terephthalate resin, polycarbonate resin, and polystyrene resin account for 90% by mass or more (preferably 95% by mass or more, and preferably 100% by mass or less) of the thermoplastic resins contained in the resin composition.

[0063] <Stabilizer> The resin composition of the present embodiment may contain a stabilizer. By containing a stabilizer, a resin composition or a molded article having excellent thermal stability can be obtained. The stabilizer preferably contains one or more compounds selected from the group consisting of thioether compounds, hindered phenol compounds, and phosphite compounds, and more preferably contains one or more compounds selected from the group consisting of hindered phenol compounds and phosphite compounds.

[0064] As the thioether-based compound, any conventionally known sulfur-containing compound can be used, and among them, thioethers are preferred. By including the thioether-based compound in the resin composition of the present embodiment, the appearance of the molded article tends to be improved and color change tends to be suppressed. Specific 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 isopropyl xanthate, 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 Shipro Chemicals' product name "Seenox 412S" and ADEKA's product name "Adekastab AO-412S."

[0065] Examples of hindered phenol compounds include pentaerythritol tetrakis(3-(3,5-di-tert-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 products include ADEKA products under the trade names "ADK STAB AO-60" and "ADK STAB AO-330," EVERSPRING CHEMICAL products under the trade name "EVERNOX-10," and BASF products under the trade name "IRGANOX1010."

[0066] The phosphite compound is preferably a compound represented by the formula: R 2 OP(OR 3 )(OR 4 ) (In the formula, R 2 , R 3 and R 4 are each a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, or an aryl group having 6 to 30 carbon atoms, and R 2 , R 3 and R 4 At least one of the groups is an aryl group having 6 to 30 carbon atoms.) Examples of the compound include compounds represented by the following formula: Examples of the phosphite compound 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, tetraphenyl dipropylene glycol diphosphite, tetraphenyl tetra(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 phosphate, tetra(tridecyl) ... propylidenediphenyl 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, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, and the like. Among these, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite is preferred. Commercially available products include those manufactured by ADEKA Corporation under the trade names "ADEKA STAB PEP-36" and "AX-71."

[0067] Other examples of stabilizers include the descriptions in paragraphs 0067 to 0075 of JP 2021-063196 A, paragraphs 0046 to 0057 of JP 2018-070722 A, paragraphs 0030 to 0037 of JP 2019-056035 A, and paragraphs 0066 to 0078 of WO 2017 / 038949 A. The contents of these descriptions are incorporated herein by reference.

[0068] The stabilizer content in the resin composition of this embodiment is preferably 0.05 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, per 100 parts by mass of the polybutylene terephthalate resin and the polystyrene-based resin combined. By ensuring that the stabilizer content is above the lower limit, the effect of suppressing thermal and oxidative degradation of the resin during melt-kneading, molding, and use as a molded product tends to be more improved, and discoloration of the resin tends to be more effectively suppressed. Furthermore, the upper limit of the stabilizer content is preferably 3.0 parts by mass or less, more preferably 2.0 parts by mass or less, and even more preferably 1.0 parts by mass or less, per 100 parts by mass of the polybutylene terephthalate resin and the polyethylene terephthalate resin combined. By ensuring that the stabilizer content is below the upper limit, adverse effects on appearance and physical properties due to aggregation of additives such as stabilizers can be effectively suppressed. The resin composition of the present embodiment may contain only one stabilizer, or may contain two or more stabilizers. When two or more stabilizers are contained, the total amount is preferably in the above range.

[0069] <Inorganic fillers> The resin composition of the present embodiment preferably further contains an inorganic filler. By containing an inorganic filler, preferably a fibrous or scaly inorganic filler, more preferably glass fiber and / or glass flake, the mechanical strength tends to be improved.

[0070] The inorganic filler that can be contained in the resin composition of this embodiment has the effect of improving the mechanical properties of the resulting resin composition when blended with the resin, and can be any inorganic filler commonly used for plastics. Preferably, fibrous inorganic fillers such as glass fiber, carbon fiber, basalt fiber, wollastonite, and potassium titanate fiber can be used. Other examples include granular or amorphous fillers such as calcium carbonate, titanium oxide, feldspar minerals, clay, organoclay, and glass beads; plate-like fillers such as talc; and scaly inorganic fillers such as glass flakes, mica, and graphite. Among these, glass fiber and / or glass flakes are preferred in terms of mechanical strength, rigidity, and heat resistance, and glass fiber is particularly preferred. Glass fiber can have either a round or irregular cross-sectional shape. It is more preferable to use an inorganic filler that has been surface-treated with a surface treatment agent such as a coupling agent. Glass fibers with a surface treatment agent attached thereto are preferred because they have excellent durability, moist heat resistance, hydrolysis resistance, and heat shock resistance.

[0071] Any conventionally known surface treatment agent can be used, and specific preferred examples include silane coupling agents such as aminosilane-based, epoxysilane-based, allylsilane-based, and vinylsilane-based silane coupling agents. Among these, aminosilane-based surface treatment agents are preferred, and specific preferred examples include γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and γ-(2-aminoethyl)aminopropyltrimethoxysilane.

[0072] Other preferred surface treatment agents include novolac-type and other epoxy resin-based surface treatment agents, and bisphenol A-type epoxy resin-based surface treatment agents, and treatment with a novolac-type epoxy resin-based surface treatment agent is particularly preferred. The silane-based surface treatment agent and the epoxy resin-based surface treatment agent may be used alone or in combination, and it is also preferable to use both of them in combination. The glass fiber in this embodiment means a fibrous glass material, and more specifically, it is preferable that the glass fiber has a chopped shape obtained by bundling 1,000 to 10,000 glass fibers and cutting them to a predetermined length. The glass fibers in this embodiment preferably have a number-average fiber length of 0.5 to 10 mm, more preferably 1 to 5 mm. By using glass fibers with such a number-average fiber length, mechanical strength can be further improved. The number-average fiber length is calculated from the measured values ​​obtained by randomly selecting glass fibers for which fiber length measurement is to be performed from an image obtained by observation with an optical microscope, measuring the long sides of the fibers. The observation is performed at a magnification of 20 times, and the number of fibers measured is 1,000 or more. This roughly corresponds to the cut length. The cross section of the glass fiber may be any shape, such as a circle, an ellipse, an oval, a rectangle, a shape in which both short sides of a rectangle are joined with semicircles, a cocoon shape, etc., but a circle is preferred. Here, the circle includes not only a circle in the geometric sense but also what is usually called a circle in the technical field of this embodiment. The lower limit of the number average fiber diameter of the glass fibers is preferably 4.0 μm or more, 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 the glass fibers is preferably 15.0 μm or less, more preferably 14.0 μm or less. Using glass fibers having a number average fiber diameter in this range tends to produce molded products with superior mechanical strength. The number average fiber diameter of the glass fibers is calculated from the measured values ​​obtained by randomly selecting glass fibers to be measured for fiber diameter from an image obtained by observation with an electron microscope, measuring the fiber diameter near the center, and then measuring the measured value. The observation is performed at a magnification of 1,000x, and the number of fibers measured is 1,000 or more. The number average fiber diameter of glass fibers having a cross section other than a circle is the number average fiber diameter when converted into a circle with the same area as the cross section.

[0073] The glass fiber is obtained by melt spinning commonly available glass such as E-glass (electrical glass), C-glass (chemical glass), A-glass (alkaline glass), S-glass (high strength glass), D-glass, R-glass, and alkali-resistant glass, but is not particularly limited as long as it can be made into glass fiber. In this embodiment, it is preferable to include E-glass.

[0074] The glass fiber used in this embodiment is preferably surface-treated with a surface treatment agent such as a silane coupling agent, for example, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, or γ-aminopropyltriethoxysilane. The amount of the surface treatment agent attached is preferably 0.01 to 1 mass% of the glass fiber. Furthermore, if necessary, the glass fiber 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 capable of forming a film, such as an epoxy resin or urethane resin, or a mixture of a resin capable of forming a film and a heat stabilizer.

[0075] Glass fibers are commercially available, such as T-286H, T-756H, T-127, and T-289H manufactured by Nippon Electric Glass Co., Ltd., DEFT2A manufactured by Owens Corning, HP3540 manufactured by PPG, and CSG3PA820 manufactured by Nitto Boseki Co., Ltd.

[0076] The content of the inorganic filler (preferably glass fiber) in the resin composition of this embodiment is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, even more preferably 20 parts by mass or more, even more preferably 25 parts by mass or more, and even more preferably 30 parts by mass or more, per 100 parts by mass of the polybutylene terephthalate resin and the polystyrene-based resin combined. By setting the content at or above the lower limit, the mechanical strength of the resulting molded article tends to be high. Furthermore, the upper limit of the content of the inorganic filler is preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 50 parts by mass or less, per 100 parts by mass of the thermoplastic resin. By setting the content at or below the upper limit, the welding strength of the interface tends to be high.

[0077] The content of the inorganic filler (preferably glass fiber) in the resin composition of this embodiment is preferably 20% by mass or more, more preferably 25% by mass or more, of the resin composition, and 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 of the present embodiment may contain only one type of inorganic filler (preferably glass fiber), or may contain two or more types. When two or more types are contained, the total amount is preferably in the above range.

[0078] <Release agent> The resin composition of the present embodiment preferably contains a release agent. A wide variety of known release agents can be used as the release agent, and examples thereof include aliphatic carboxylic acid amides, aliphatic carboxylic acids, esters of aliphatic carboxylic acids and alcohols, aliphatic hydrocarbon compounds having a number average molecular weight of 200 to 15,000, and polysiloxane-based silicone oils, with aliphatic carboxylic acid amides and / or aliphatic hydrocarbon compounds having a number average molecular weight of 200 to 15,000 being preferred.

[0079] Examples of the aliphatic carboxylic acid amides include compounds obtained by a dehydration reaction between a higher aliphatic monocarboxylic acid and / or a polybasic acid and a diamine. As the higher aliphatic monocarboxylic acid, saturated aliphatic monocarboxylic acids and hydroxycarboxylic acids having 16 or more carbon atoms are preferred, and examples thereof include 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. The carboxylic acid amide compound is preferably a compound obtained by polycondensation of stearic acid, sebacic acid, and ethylenediamine, and more preferably a compound obtained by polycondensation of 2 moles of stearic acid, 1 mole of sebacic acid, and 2 moles of ethylenediamine. In addition to bisamide compounds obtained by reacting diamines with aliphatic carboxylic acids, such as N,N'-methylenebisstearamide and N,N'-ethylenebisstearamide, dicarboxylic acid amide compounds such as N,N'-dioctadecylterephthalamide can also be suitably used.

[0080] Examples of aliphatic carboxylic acids include saturated or unsaturated aliphatic mono-, di-, or tri-carboxylic acids. Aliphatic carboxylic acids also include alicyclic carboxylic acids. Among these, preferred aliphatic carboxylic acids are mono- or di-carboxylic acids having 6 to 36 carbon atoms, with saturated aliphatic mono-carboxylic acids having 6 to 36 carbon atoms being more preferred. Specific examples of such aliphatic carboxylic acids include palmitic acid, stearic acid, caproic acid, capric acid, lauric acid, arachic acid, behenic acid, lignoceric acid, cerotic acid, melissic acid, tetralinic acid, montanic acid, adipic acid, and azelaic acid.

[0081] The aliphatic carboxylic acid in the ester of an aliphatic carboxylic acid and an alcohol can be, for example, the same as the aliphatic carboxylic acid. On the other hand, the alcohol can be, for example, a saturated or unsaturated monohydric or polyhydric alcohol. These alcohols may have a substituent such as a fluorine atom or an aryl group. Among these, monohydric or polyhydric saturated alcohols having 30 or less carbon atoms are preferred, and aliphatic or alicyclic saturated monohydric alcohols or aliphatic saturated polyhydric alcohols having 30 or less 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 containing myricyl palmitate as a main component), 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.

[0082] Examples of aliphatic hydrocarbons having a number average molecular weight of 200 to 15,000 include liquid paraffin, paraffin wax, microcrystalline wax, polyethylene wax, Fischer-Tropsch wax, and α-olefin oligomers having 3 to 12 carbon atoms. Note that the aliphatic hydrocarbons herein also include alicyclic hydrocarbons. The number average molecular weight of the aliphatic hydrocarbons is preferably 5,000 or less.

[0083] Examples of polyolefin waxes include polyethylene wax, polypropylene wax, and polyethylene propylene wax, with polyethylene wax being preferred. The 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 waxes have excellent compatibility with polyalkylene terephthalate resins and tend to effectively suppress mold deposits in the resulting resin composition.

[0084] Oxidized polyolefin waxes can be obtained by oxidizing the corresponding unmodified polyolefin waxes. Examples of oxidized polyethylene waxes include Licowax (registered trademark) PED521, PED522, and PED121 manufactured by Clariant Chemicals; Ceridust (registered trademark) 3715, etc. In addition to the above, commercially available polyolefin waxes can be found in paragraph 0028 of JP-A-2022-140470, the contents of which are incorporated herein by reference.

[0085] 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. By setting it to the lower limit or above, glowing time tends to be further shortened. 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. By setting it to the upper limit or below, the fluidity of the resin composition during molding tends to be further improved. The weight average molecular weight can be measured by GPC (gel permeation chromatography) using a Tosoh HLC-8320GPC EcoSEC with tetrahydrofuran as the solvent and 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, and can be measured as a polystyrene-equivalent value detected with a detector (UV-8320) at a detection wavelength of 254 nm. When the resin composition of the present embodiment contains two or more types of polyolefin waxes, the weight average molecular weight is the weight average molecular weight of the mixture.

[0086] 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, particularly more preferably 130°C or lower, and 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 the temperature at which a polyolefin wax is heated to change from a solid to a liquid state and the first drop of molten material falls from a standard cup with a 2.8 mm opening.

[0087] In addition to the above, the release agent can be found in paragraphs 0063 to 0077 of JP 2018-070722 A and paragraphs 0090 to 0098 of JP 2019-123809 A, the contents of which are incorporated herein by reference.

[0088] 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 polybutylene terephthalate resin and the polystyrene-based resin combined, more preferably 0.1 parts by mass or more, even more preferably 0.3 parts by mass or more, and even more preferably 0.5 parts by mass or more, and preferably 5 parts by mass or less, more preferably 4 parts by mass or less, even more preferably 3 parts by mass or less, and even more preferably 2 parts by mass or less. By setting the content at or above the lower limit, the releasability of the resulting molded article tends to be further improved. Furthermore, by setting the content at or below the upper limit, bleeding out of the resulting molded article can be effectively suppressed. The resin composition may contain only one type of release agent, or may contain two or more types. When two or more types are contained, the total amount is preferably in the above range.

[0089] <Coloring agent> The resin composition of the present embodiment may contain a colorant (dye and / or pigment). By containing a colorant, the design of the resulting molded article can be improved. The colorant may be a dye or a pigment. The dye used in this embodiment is preferably a black dye and / or a black dye composition. The black dye composition refers to a dye composition that exhibits black by combining two or more chromatic dyes such as red, blue, and green. A first embodiment of the black dye composition is a composition that contains a green dye and a red dye. A second embodiment of the black dye composition is a composition that contains a red dye, a blue dye, and a yellow dye.

[0090] Examples of commercially available light-transmitting dyes include colorants Plast Yellow 8000, Plast Red M 8315, Plast Red 8370, and Oil Green 5602 manufactured by Arimoto Chemical Co., Ltd.; colorants Macrolex Yellow 3G, Macrolex Red EG, and Macrolex Green 5B manufactured by LANXESS; and colorants KP Plast HK, KP Plast Red HG, KP Plast Red H2G, KP Plast Blue R, KP Plast Blue GR, and KP Plast Green G manufactured by Kiwa Chemical Industry Co., Ltd. Furthermore, dyes described in Japanese Patent No. 4157300 and Japanese Patent No. 4040460 can also be used, the contents of which are incorporated herein by reference.

[0091] Examples of pigments used in this embodiment include inorganic pigments (black pigments such as carbon black (e.g., acetylene black, lamp black, thermal black, furnace black, channel black, ketjen black, etc.), red pigments such as iron oxide red, orange pigments such as molybdate orange, and white pigments such as titanium oxide), and organic pigments (yellow pigments, orange pigments, red pigments, blue pigments, green pigments, etc.), with black pigments being preferred and carbon black being more preferred. When the resin composition of the present embodiment contains a pigment, it is preferable to use it as a masterbatch with a thermoplastic resin (preferably a polyester resin, more preferably a polybutylene terephthalate resin). The concentration of the pigment in the masterbatch is preferably 1 to 50 mass %.

[0092] When the resin composition of the present embodiment contains a colorant, the content thereof is preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, even more preferably 0.4 parts by mass or more, and even more preferably 0.6 parts by mass or more, relative to 100 parts by mass of the total of the polybutylene terephthalate resin and the polystyrene-based resin, and is preferably 5 parts by mass or less, and more preferably 4 parts by mass or less. The resin composition of the present embodiment may contain only one type of colorant, or may contain two or more types. When two or more types are contained, the total amount is preferably in the above range.

[0093] <Other ingredients> The resin composition of this embodiment may contain other components in addition to those described above, as necessary, as long as the desired physical properties are not significantly impaired. Examples of other components include various resin additives. One type of other component may be contained, or two or more types may be contained in any combination and ratio. The total amount of these other components is preferably 0 to 5% by mass, more preferably 0 to 3% by mass, and even more preferably 0 to 1% by mass, based on 100% by mass of the resin composition. Specific examples include reactive compounds, ultraviolet absorbers, antistatic agents, antifogging agents, antiblocking agents, flow improvers, plasticizers, dispersants, and antibacterial agents. In addition, the resin composition of this embodiment can be blended with additives described in paragraphs 0047 to 0103 of WO 2021 / 241471 within the scope of the present invention, the contents of which are incorporated herein by reference. In the resin composition of this embodiment, the total of the polybutylene terephthalate resin, the polystyrene-based resin, and the glass fiber preferably accounts for 80% by mass or more of the resin composition, more preferably 85% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more, and may be 100% by mass or less. Furthermore, in the resin composition of the present embodiment, the polybutylene terephthalate resin, polystyrene-based resin, polycarbonate resin, and optionally blended glass fiber, stabilizer, release agent, and colorant preferably account for 90% by mass or more of the resin composition, more preferably 95% by mass or more, and even more preferably 97% by mass or more. They may also account for 99% by mass or more, or 100% by mass or less.

[0094] <Method of manufacturing resin composition> The resin composition of this embodiment can be produced by a conventional method for preparing a resin composition (e.g., pellets). Typically, the components and various optional additives 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 without premixing the components, or by premixing only a portion of the components, feeding the mixture into an extruder using a feeder and melt-kneading the mixture. For example, it is preferable to feed glass fibers into an extruder using a side feeder and melt-knead them. Alternatively, a masterbatch may be prepared by melt-kneading some of the components, such as a colorant, with a thermoplastic resin to prepare a masterbatch, and then blending the remaining components with the masterbatch and melt-kneading the resulting mixture.

[0095] <Method of manufacturing molded products> The resin composition or pellets of this embodiment are molded according to a known method. The method for producing the molded article is not particularly limited, and any molding method generally used for resin compositions can be used. Examples thereof include injection molding, ultra-high speed injection molding, injection compression molding, two-color molding, gas-assisted or other hollow molding, molding using a heat-insulating mold, molding using a rapid heating 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., among which injection molding is preferred. For details of the injection molding method, please refer to the description in paragraphs 0113 to 0116 of Japanese Patent No. 6183822, the contents of which are incorporated herein by reference. Furthermore, the mold temperature during molding such as injection molding is preferably 40 to 150°C.

[0096] <Application> The resin composition of the present embodiment is used as a molded article formed from the resin composition or pellets. The uses of the resin composition and pellets are not particularly limited, and they can be widely used as resin compositions for injection molding. The application fields of the material include, for example, materials for electrical and electronic devices, vehicle materials, housing materials, and materials for manufacturing parts in other industrial fields, both indoors and outdoors. In this embodiment, particularly preferred applications include food containers, pharmaceutical containers, containers for oil and fat products, hollow vehicle parts (various tanks, intake manifold parts, camera housings), vehicle electrical parts (various control units, ignition coil parts, etc.), motor parts, various sensor parts, connector parts, switch parts, breaker parts, relay parts, coil parts, transformer parts, lamp parts, housings for automotive interior and exterior parts, etc. [Example]

[0097] The present invention will be explained in more detail below with reference to examples. The materials, amounts used, ratios, processing details, processing procedures, etc. shown in the following examples can be appropriately changed without departing 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 the like, measurements can be made using other instruments with equivalent performance.

[0098] 1. Raw materials The following raw materials were used: [Table 1]

[0099] <Synthesis Example 1> A slurry containing 1.80 moles of 1,4-butanediol (BDO) mixed with 1.00 moles of terephthalic acid was continuously fed to an esterification reactor equipped with a screw agitator and filled with PBT oligomer with an esterification rate of 99%, where the esterification reaction was carried out. A titanium catalyst solution of tetrabutyl titanate was added to the esterification reactor in an amount that resulted in a titanium concentration of 40 ppm by mass relative to the PBT. Additional BDO was added to the esterification reactor so that the molar ratio of BDO to terephthalic acid was 3.2. The reactor temperature was 226°C, the pressure was 60 kPa, and the average residence time was 180 minutes.

[0100] Next, the PBT oligomer with an esterification rate of 96.5% was continuously transferred to the first polycondensation reaction tank. In the first polycondensation reaction tank, a continuous polycondensation reaction was carried out. The reaction temperature was 230 °C, the pressure was 3.9 kPa, and the average residence time was 120 minutes. Then, this product was transferred to the second polycondensation reaction tank, and a continuous polycondensation reaction was carried out. The reaction temperature was 240 °C, the pressure was 130 Pa, and the average residence time was 60 minutes.

[0101] The obtained polymer was continuously extruded from the die head in a strand form through a filter via an extraction line by an extraction gear pump, and cut with a rotary cutter to obtain PBT pellets (major diameter: about 3 mm, minor diameter: about 2 mm, length: about 4 mm).

[0102] <Measurement of Ti Concentration, Na Concentration, and Ca Concentration> Qualitative / semi - quantitative analysis (μg / g) of Ti, Na, and Ca in the polybutylene terephthalate resin was performed by ICP emission spectrometry. In this case, as a pretreatment, 200 mg of the sample was weighed, and Kjeldahl wet digestion (sulfuric acid / nitric acid, sulfuric acid / hydrogen peroxide) was carried out, and the volume was made up to 50 mL. Subsequently, ICP emission analysis was performed by the acid concentration matching single - point calibration method. The unit was shown in mass ppm. ICP emission analysis was performed using "iCAP7600duoiCAP76000uo" manufactured by ThermoThrmo Fisher Scientific, with axial / radial photometry. <U

[0103] <Active Titanium Parameter X and Ratio α of Active Titanium> Five capillaries with an inner diameter of 5 mm were filled with the powder of the polybutylene terephthalate resin (pellets) obtained above. Next, after thoroughly purging the contents with nitrogen, the capillaries were immersed in an oil bath accurately controlled at 245 °C (temperature T), taken out over time, and quenched with liquid nitrogen. Then, the contents were taken out, and the terminal carboxyl group concentration and terminal hydroxyl group concentration were determined. Using these values, the ratio α of active titanium was determined from Formula (1), Formula (2), and Formula (3). [[ID=二十二]]

Number

number

[0104] The evaluation of the change in terminal carboxyl group concentration over time is performed in a nitrogen atmosphere to prevent the influence of oxygen. Furthermore, if the water concentration in the polybutylene terephthalate resin being evaluated is high, hydrolysis reactions occur frequently, making it difficult to accurately understand the decomposition behavior associated with catalytic activity other than hydrolysis. Therefore, a low water concentration of 300 mass ppm or less is preferable. The evaluation is performed at a temperature of 245°C. Under these heat treatment conditions, the decrease in number average molecular weight due to reactions other than hydrolysis caused by the water contained in the polybutylene terephthalate resin can be ignored. The increase in terminal carboxyl group concentration due to hydrolysis reactions can be considered equal to the increase in terminal hydroxyl group concentration before and after heat treatment. Therefore, the change in terminal carboxyl group concentration due to thermal decomposition reactions other than hydrolysis reactions can be calculated using the following equation (4).

[0105] Formula (4)

number

[0106] <Intrinsic viscosity (IV)> The intrinsic viscosity was measured by the following method. Polybutylene terephthalate resin pellets were dissolved in a mixed solvent of phenol / 1,1,2,2-tetrachloroethane (1 / 1 by mass) by stirring at 110°C for 1 hour to a concentration of 1.00 g / dL. The solution was then cooled to 30°C. Using a fully automatic solution viscometer, the number of seconds it took for the sample solution and the solvent alone to fall at 30°C were measured, and the intrinsic viscosity was calculated using the formula: Intrinsic viscosity=((1+4K H η sp ) 0.5 -1) / (2KH C) where η sp =η / η0-1, where η is the time it takes for the sample solution to fall, η0 is the time it takes for the solvent alone to fall, C is the concentration of the sample solution (g / dL), and K H is Huggins' constant. K H The value was 0.33. The unit is dL / g. The fully automatic solution viscometer used was manufactured by Shibayama Scientific Co., Ltd.

[0107] <Terminal carboxyl group concentration (acid value)> The terminal carboxyl group concentration of polybutylene terephthalate resin was determined by dissolving 0.5 g of polybutylene terephthalate resin in 25 mL of benzyl alcohol and titrating it with a 0.01 mol / L benzyl alcohol solution of sodium hydroxide. The unit is μmol / g (μeq / g).

[0108] <Terminal hydroxyl group concentration> The terminal hydroxyl group concentration of polyalkylene terephthalate resin was measured by dissolving 25 mg of sample in a vial in 0.75 mL of a 7 / 3 volumetric mixture of deuterated chloroform and hexafluoroisopropanol containing a trace of TMS (tetramethylsilane). 25 μL of deuterated pyridine was added and the sample was transferred to a 5 mm NMR sample tube. H NMR spectra were measured using a Brooke AVANCE NEO 600 spectrometer. The resonance frequency was 600, 1 MHz, the flip angle was 45°, the data acquisition time was 3 s, the pulse repetition time was 10 s, the number of accumulations was 16, and the temperature was 25 °C. The unit is μmol / g.

[0109] <Terminal vinyl group concentration> The terminal vinyl group concentration of the polyalkylene terephthalate resin was measured under the same conditions as the terminal hydroxyl group concentration of the polyalkylene terephthalate resin, and the unit is μmol / g.

[0110] [Table 2]

[0111] Example 1, Example 2, Comparative Example 1 <Compound> The components shown in Table 1 were mixed uniformly in a tumbler mixer in the proportions shown in Table 3 (each component in Table 3 is shown in parts by mass), with the exception of the glass fiber. The resulting mixture was fed into a twin-screw extruder ("TEX30α" manufactured by The Japan Steel Works, Ltd.) through the main feed port. The cylinder temperature of the first kneading section was set to 260°C, and the glass fiber was fed through a side feeder. The resin composition was melt-kneaded under conditions of a cylinder temperature setting of 220°C and a screw rotation speed of 200 rpm after the addition of the glass fiber, and then quenched in a water bath and pelletized using a pelletizer to obtain pellets of the resin composition.

[0112] <Tensile properties> The resin pellets obtained above were dried at 120°C for 5 hours, and then ISO multipurpose test specimens (thickness 4 mm) were injection molded using an injection molding machine ("J85AD" manufactured by The Japan Steel Works, Ltd.) under conditions of a cylinder temperature of 250°C and a mold temperature of 80°C. Using the molded multipurpose ISO multipurpose test specimens, the tensile strength (unit: MPa) and tensile modulus (unit: MPa) were measured in accordance with ISO527-1 and ISO527-2.

[0113] <Weld strength> Tests were conducted in accordance with ISO 527-1 and 2 using a 4mm thick 1A-type test piece at a test speed of 5mm / min. A mold with two gates (gate distance 170mm) on the center line of the surface in the longitudinal direction of the test piece was used, and the test piece with a weld formed in the center was molded under conditions of a cylinder temperature of 250°C, a mold temperature of 80°C, and a molding cycle of 40 seconds, and the weld strength (unit: MPa) was measured.

[0114] <Deflection temperature under load (DTUL)> Using the above ISO multipurpose test piece (4 mm thick), the deflection temperature under load (unit: °C) was measured under a load of 1.80 MPa in accordance with ISO75-1 and ISO75-2.

[0115] <Amount of gas generated> The amount of gas (THF) generated in the resin composition was measured according to the following method. The pellets of the resin composition were heated at 150°C for 10 minutes, and the resulting gas was analyzed. The gas analysis was carried out by headspace gas chromatography. The amount of generated gas (THF) was measured. Gas analysis was performed using a Nexis GC-2030 manufactured by Shimadzu Corporation.

[0116] [Table 3]

[0117] As is clear from the above results, molded articles formed from the resin composition of the present invention had high weld strength. Furthermore, they also had excellent tensile properties and high deflection temperatures under load (Examples 1 and 2). Furthermore, the amount of gas contained in the pellets could be reduced. In contrast, when the active titanium content was outside the range of the present invention, the weld strength was significantly low, and the tensile properties were also poor (Comparative Example 1).

[0118] Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the invention.

Claims

1. Contains polybutylene terephthalate resin and polystyrene-based resin, The polybutylene terephthalate resin A resin composition having an active titanium parameter X shown below of 25 or less. [Equation 1] [Equation 2]

2. The resin composition according to claim 1, wherein the polybutylene terephthalate resin contains 30 to 500 ppm by mass of titanium element.

3. The resin composition according to claim 1, wherein the polybutylene terephthalate resin contains 0.1 to 100 ppm by mass of sodium element.

4. The resin composition according to claim 1, wherein the polybutylene terephthalate resin contains 0.1 to 3000 ppm by mass of calcium element.

5. 2. The resin composition according to claim 1, wherein the proportion α of active titanium represented by the following formula (3) in the polybutylene terephthalate resin is 0.50 or less. α=X / M...Formula (3) (In formula (3), X is the active titanium parameter, and [M] is the titanium element concentration (ppm by mass) in the polybutylene terephthalate resin.)

6. The resin composition according to claim 1 , wherein the polybutylene terephthalate resin comprises a polybutylene terephthalate resin derived from recycled materials.

7. The resin composition according to claim 1 , wherein the polybutylene terephthalate resin comprises two or more polybutylene terephthalate resins having different intrinsic viscosities.

8. The resin composition according to claim 1, which is for injection molding.

9. The resin composition according to claim 1, wherein the polybutylene terephthalate resin has a terminal carboxyl group concentration of 25 μmol / g or more.

10. The resin composition according to claim 1, wherein the active titanium parameter X is 12 or less.

11. The resin composition according to claim 1 , wherein the polybutylene terephthalate resin has an Mw / Mn ratio of 2.1 or more.

12. the polybutylene terephthalate resin contains 0.1 to 500 ppm by mass of sodium element, the polybutylene terephthalate resin contains 0.1 to 3000 ppm by mass of calcium element, The proportion α of active titanium represented by the following formula (3) in the polybutylene terephthalate resin is 0.50 or less, The polybutylene terephthalate resin contains polybutylene terephthalate resin derived from material recycling, the polybutylene terephthalate resin contains two or more polybutylene terephthalate resins having different intrinsic viscosities, The resin composition according to claim 1, which is for injection molding. α=X / M...Formula (3) (In formula (3), X is the active titanium parameter, and [M] is the titanium element concentration (ppm by mass) in the polybutylene terephthalate resin.)

13. the polybutylene terephthalate resin contains 0.1 to 100 ppm by mass of sodium element, the polybutylene terephthalate resin contains 0.1 to 3000 ppm by mass of calcium element, The proportion α of active titanium represented by the following formula (3) in the polybutylene terephthalate resin is 0.50 or less, The polybutylene terephthalate resin contains polybutylene terephthalate resin derived from material recycling, the polybutylene terephthalate resin contains two or more polybutylene terephthalate resins having different intrinsic viscosities, For injection molding, The polybutylene terephthalate resin has a terminal carboxyl group concentration of 25 μmol / g or more, The active titanium parameter X is 12 or less, The resin composition according to claim 1 , wherein the polybutylene terephthalate resin has an Mw / Mn ratio of 2.1 or more. α=X / M...Formula (3) (In formula (3), X is the active titanium parameter, and [M] is the titanium element concentration (ppm by mass) in the polybutylene terephthalate resin.)

14. Pellets of the resin composition according to any one of claims 1 to 13.

15. A molded article formed from the resin composition according to any one of claims 1 to 13.

16. A molded article formed from the pellets of claim 14.

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