Resin composition and molded object

Abstract

Provided are a resin composition and a molded object. A resin composition comprising, with respect to 100 parts by mass of resin components including a polybutylene terephthalate resin, 2-15 parts by mass of an elastomer, 3-20 parts by mass of a hydroxyl group-containing compound, and 3-20 parts by mass of a conductive carbon, wherein the hydroxyl group-containing compound has, when being subjected to analysis using 1H NMR, a hydroxyl group concentration, which is the proportion of peak area derived from hydroxyl groups with respect to the total peak area and which is represented by [(hydroxyl group derived peak area / total peak area )×100], in a range of 0.5-15.0%.

Description

Resin composition and molded article

[0001] The present invention relates to a resin composition and a molded article, and in particular to an electrically conductive resin composition suitable for electrostatic coating of a water-based paint.

[0002] Polybutylene terephthalate resin is easy to process and has excellent mechanical properties, electrical properties, heat resistance, and other physical and chemical properties, which is why it is widely used in automobile parts, electrical and electronic equipment parts, and other precision equipment parts.

[0003] Currently, automotive fuel oil cap parts are mainly made of steel sheets, but in recent years, plastic fuel oil cap parts have been attracting attention due to their high degree of freedom in shape. Furthermore, to reduce process costs, these parts are primarily painted using online electrostatic painting.

[0004] Conductive resin compositions have been proposed as materials for electrostatic coating. For example, Patent Document 1 discloses a conductive polyester resin composition containing conductive carbon black, an ethylene copolymer-based impact modifier, and a hyperbranched polyester.

[0005] Furthermore, in recent years, there has been an increasing demand for moldability in order to accommodate the molding of parts having complex shapes. To improve moldability, resin materials are required to have improved fluidity when melted. For example, Patent Document 2 discloses a polybutylene terephthalate resin composition containing a thermoplastic elastomer and an acrylic oligomer.

[0006] International Publication No. 2019 / 037122 International Publication No. 2008 / 075776

[0007] Here, molded articles formed from compositions containing polybutylene terephthalate resin and conductive carbon are sometimes painted with paint to impart design, rust resistance, and weather resistance. However, as a result of studies by the present inventors, it was found that when a molded article formed from a composition containing polybutylene terephthalate resin and conductive carbon is painted with a water-based paint, adhesion between the molded article and the water-based paint is low, and the water-based paint is likely to peel off. The present invention aims to solve this problem and to provide a resin composition and a molded article that are a resin composition containing polybutylene terephthalate resin and conductive carbon, and that, when painted with a water-based paint, can provide a molded article that has high adhesion to the water-based paint and is less likely to peel off the water-based paint.

[0008] In light of the above-mentioned problems, the present inventors have conducted extensive research and found that the above-mentioned problems can be solved by blending a resin component containing polybutylene terephthalate resin with an elastomer, a hydroxyl group-containing compound, and conductive carbon in predetermined proportions. Specifically, the above-mentioned problems have been solved by the following means: <1> A resin composition containing 2 to 15 parts by mass of an elastomer, 3 to 20 parts by mass of a hydroxyl group-containing compound, and 3 to 20 parts by mass of conductive carbon, relative to 100 parts by mass of a resin component containing polybutylene terephthalate resin, wherein the hydroxyl group-containing compound is １A resin composition having a hydroxyl group concentration, expressed as a ratio of the peak area attributable to hydroxyl groups to the total peak area, [(peak area attributable to hydroxyl groups / total peak area) × 100], in the range of 0.5 to 15.0% when analyzed by H NMR. <2> The resin composition according to <1>, wherein the resin component further contains a polycarbonate resin. <3> The resin composition according to <2>, wherein the resin component further contains 0.05 to 2 parts by mass of a phosphorus-based stabilizer per 100 parts by mass of the resin component. <4> The resin composition according to any one of <1> to <3>, wherein the polybutylene terephthalate resin has an intrinsic viscosity of 1.00 to 1.50 dL / g. <5> The resin composition according to any one of <1> to <4>, wherein the elastomer contains an epoxy group-containing compound. <6> The resin composition according to any one of <1> to <5>, wherein the hydroxyl group-containing compound has a weight-average molecular weight of 1,500 to 30,000. <7> The resin composition according to any one of <1> to <6>, wherein the hydroxyl group-containing compound comprises a (meth)acrylic compound. <8> The resin composition according to any one of <1> to <7>, wherein the hydroxyl group-containing compound is an amorphous compound. <9> The resin composition according to any one of <1> to <8>, wherein the hydroxyl group concentration of the hydroxyl group-containing compound is in the range of 0.5 to 10.0%. <10> The resin composition according to any one of <1> to <9>, which is used to form a molded article to be electrostatically coated with a water-based paint. <11> A molded article formed from the resin composition according to any one of <1> to <10>. <12> The molded article according to <11>, which is a fuel oil spout.

[0009] The present invention makes it possible to provide a resin composition containing polybutylene terephthalate resin and conductive carbon, which can provide a molded article that has high adhesion to a water-based paint when coated with the water-based paint, and from which the water-based paint is less likely to peel off, and a molded article.

[0010] Hereinafter, a detailed description will be given of an embodiment of the present invention (hereinafter simply referred to as "the present embodiment"). The following present embodiment is an example for explaining the present invention, and the present invention is not limited to this embodiment. In this specification, the term "to" is used to mean that the numerical values ​​before and after the term are included as lower and upper limits. In this specification, various physical property values ​​and characteristic values ​​are those at 23°C unless otherwise specified. In the description of a group (atomic group) in this specification, a notation that does not indicate substituted or unsubstituted encompasses both a group (atomic group) that has no substituent and a group (atomic group) that has a substituent. For example, the term "alkyl group" encompasses not only an alkyl group that has no substituent (unsubstituted alkyl group) but also an alkyl group that has a substituent (substituted alkyl group). In this specification, when a notation that does not indicate substituted or unsubstituted is used, unsubstituted is preferred. In this specification, "(meth)acrylate" refers to both or either acrylate and methacrylate, and "(meth)acrylic" refers to both or either acrylic and methacrylic. In this specification, the weight average molecular weight is a polystyrene equivalent value measured by GPC (gel permeation chromatography). In this specification, the term "process" refers not only to an independent process, but also to a process that cannot be clearly distinguished from other processes as long as the intended effect of the process is achieved. In this specification, ppm means mass ppm. If the standards shown in this specification differ depending on the year, such as the measurement method, they shall be based on the standards as of January 1, 2021, unless otherwise stated.

[0011] The resin composition of the present embodiment contains 2 to 15 parts by mass of an elastomer, 3 to 20 parts by mass of a hydroxyl group-containing compound, and 3 to 20 parts by mass of conductive carbon, relative to 100 parts by mass of a resin component containing a polybutylene terephthalate resin, and the hydroxyl group-containing compound is １The hydroxyl group concentration, which is the ratio of the hydroxyl group-attributed peak area to the total peak area when analyzed by H NMR, is in the range of 0.5 to 15.0%, [(hydroxyl group-attributed peak area / total peak area) × 100]. By adopting the above configuration, a resin composition containing polybutylene terephthalate resin and conductive carbon can be obtained, which, when coated with a water-based paint, can provide a molded article that exhibits high adhesion to the water-based paint and is resistant to peeling of the water-based paint. This is presumably because the polybutylene terephthalate resin and the hydroxyl group-containing compound are adequately compatible, allowing the hydroxyl group-containing compound to precipitate on the surface of the resulting molded article without separating from the polybutylene terephthalate resin. The hydroxyl groups of this hydroxyl group-containing compound interact with the water-based paint, dramatically improving paint adhesion.

[0012] <<Polybutylene terephthalate resin>> Polybutylene terephthalate resins are produced on a large scale by reacting terephthalic acid with 1,4-butanediol. In this embodiment, commercially available resins can be used. Some polybutylene terephthalate resins contain copolymerization components other than the terephthalic acid component and the 1,4-butanediol component. In this embodiment, polybutylene terephthalate resins containing copolymerization components in an amount of preferably 3 to 40% by mass, more preferably 5 to 30% by mass, and even more preferably 10 to 25% by mass can also be used.

[0013] The intrinsic viscosity (IV) of the polybutylene terephthalate resin is preferably 1.00 dL / g or more, more preferably 1.10 dL / g or more, even more preferably 1.18 dL / g or more, and even more preferably 1.20 dL / g or more. The intrinsic viscosity is preferably 1.50 dL / g or less, more preferably 1.40 dL / g or less, even more preferably 1.35 dL / g or less, even more preferably 1.30 dL / g or less, even more preferably 1.28 dL / g or less, even more preferably 1.27 dL / g or less, and particularly preferably 1.26 dL / g or less. By setting the IV at or above the lower limit, excellent toughness can be exhibited. Furthermore, by setting the IV at or below the upper limit, the resin composition does not lose its fluidity, tending to exhibit excellent moldability. The intrinsic viscosity of the polybutylene terephthalate resin here is measured at 30°C in a phenol / tetrachloroethane (1 / 1 mass ratio) mixed solvent. The amount of terminal carboxyl groups in the polybutylene terephthalate resin is typically 60 eq / ton or less, preferably 50 eq / ton or less, and more preferably 30 eq / ton or less. By adjusting the amount to 60 eq / ton or less, alkali resistance and hydrolysis resistance are improved, and gas generation during melt molding of the resin composition is reduced. While the lower limit of the amount of terminal carboxyl groups is not particularly specified, taking into consideration the productivity of polybutylene terephthalate resin production, it is typically 10 eq / ton. The amount of terminal carboxyl groups in the polybutylene terephthalate resin can be determined by dissolving 0.5 g of the resin in 25 mL of benzyl alcohol and titrating with a 0.01 mol / L benzyl alcohol solution of sodium hydroxide.

[0014] The polybutylene terephthalate resin may be 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. These copolymers refer to those in which the copolymerization amount is 1 mol% or more and less than 50 mol% of the total polybutylene terephthalate resin segments. The copolymerization amount is preferably 2 to 50 mol%, more preferably 3 to 40 mol%, and particularly preferably 5 to 20 mol%. For details, see paragraphs 0014 to 0022 of JP 2019-006866 A, the contents of which are incorporated herein by reference.

[0015] The catalyst used in carrying out the esterification reaction may be a conventionally known catalyst, such as a titanium compound, a tin compound, a magnesium compound, or a calcium compound. Among these, titanium compounds are particularly preferred. Specific examples of titanium compounds used as esterification catalysts include titanium alcoholates such as tetramethyl titanate, tetraisopropyl titanate, and tetrabutyl titanate, and titanium phenolates such as tetraphenyl titanate.

[0016] The content of the polybutylene terephthalate resin in the resin composition of this embodiment is preferably 30 parts by mass or more, more preferably 40 parts by mass or more, even more preferably 45 parts by mass or more, and even more preferably 50 parts by mass or more, per 100 parts by mass of the resin component containing the polybutylene terephthalate resin. By setting the content at or above the lower limit, chemical resistance tends to be further improved. Furthermore, the content of the polybutylene terephthalate resin is preferably 99 parts by mass or less, more preferably 90 parts by mass or less, even more preferably 80 parts by mass or less, even more preferably 70 parts by mass or less, and even more preferably 60 parts by mass or less. Setting the content at or below the upper limit tends to more effectively reduce the amount of warpage of the molded article. The resin composition of this 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 preferably falls within the above range.

[0017] <<Polycarbonate Resin>> The resin composition of this embodiment may contain a polycarbonate resin in addition to a polybutylene terephthalate resin. The inclusion of a polycarbonate resin can effectively improve the impact resistance of the resulting molded article. Furthermore, molded articles containing both a polybutylene terephthalate resin and a polycarbonate resin as resin components tend to peel when coated with a water-based paint. However, in this embodiment, the inclusion of a hydroxyl group-containing compound can effectively suppress peeling of the water-based paint. The polycarbonate resin is obtained by reacting a dihydroxy compound or a small amount of a polyhydroxy compound with phosgene or a carbonate diester, and may be branched, a homopolymer, or a copolymer. The method for producing the polycarbonate resin is not particularly limited, and polycarbonate resins produced by the conventionally known phosgene method (interfacial polymerization method) or melt method (ester exchange method) can be used.

[0018] The dihydroxy compound used as the raw material is preferably an aromatic dihydroxy compound, and examples thereof include 2,2-bis(4-hydroxyphenyl)propane (=bisphenol A), tetramethylbisphenol A, bis(4-hydroxyphenyl)-p-diisopropylbenzene, hydroquinone, resorcinol, and 4,4-dihydroxydiphenyl, more preferably bisphenol A. Furthermore, compounds in which one or more tetraalkylphosphonium sulfonates are bonded to the above aromatic dihydroxy compounds can also be used.

[0019] Among the polycarbonate resins mentioned above, aromatic polycarbonate resins derived from 2,2-bis(4-hydroxyphenyl)propane or aromatic polycarbonate copolymers derived from 2,2-bis(4-hydroxyphenyl)propane and other aromatic dihydroxy compounds are preferred. Furthermore, copolymers primarily composed of aromatic polycarbonate resins, such as copolymers with polymers or oligomers having a siloxane structure, may also be used. Furthermore, two or more of the above-mentioned polycarbonate resins may be mixed and used.

[0020] 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.

[0021] The viscosity average molecular weight (Mv) of the polycarbonate resin is preferably 10,000 or more, more preferably 15,000 or more, and even more preferably 20,000 or more. By using a polycarbonate resin having a viscosity average molecular weight of 10,000 or more, the mechanical strength of the resulting resin composition tends to be further improved. Furthermore, the viscosity average molecular weight (Mv) of the polycarbonate resin is preferably 60,000 or less, more preferably 40,000 or less, and even more preferably 30,000 or less. By using a polycarbonate resin having a viscosity average molecular weight of 60,000 or less, the flowability of the resin composition tends to be improved, and moldability tends to be improved.

[0022] In this embodiment, the viscosity average molecular weight (Mv) of the 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 20°C using an Ubbelohde viscometer, and then using the following Schnell viscosity formula: [η] = 1.23 × 10 －４ Mv ０．８３

[0023] 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.

[0024] The content of the polycarbonate resin is preferably 1 part by mass or more, more preferably 10 parts by mass or more, even more preferably 20 parts by mass or more, still more preferably 30 parts by mass or more, and even more preferably 40 parts by mass or more, per 100 parts by mass of the resin component containing the polybutylene terephthalate resin. The content of the polycarbonate resin is preferably 70 parts by mass or less, more preferably 60 parts by mass or less, even more preferably 55 parts by mass or less, and even more preferably 50 parts by mass or less, per 100 parts by mass of the resin component containing the polybutylene terephthalate resin. By adjusting the content to such a level, the impact resistance of a molded article using the resin composition can be improved and warpage can be reduced. The resin composition of this embodiment may contain only one type of carbonate resin, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0025] The mass ratio of the polybutylene terephthalate resin to the polycarbonate resin is preferably 50-90 / 50-10, more preferably 50-70 / 50-30, and even more preferably 50-60 / 50-40.

[0026] The resin composition of this embodiment may or may not contain resin components other than polybutylene terephthalate resin and polycarbonate resin. When the resin composition of this embodiment contains other resin components, examples include styrene-based resins, polyethylene terephthalate resins, polyarylate resins, modified polyphenylene ether resins, and polyamide resins. Among the components described below under "elastomers and other additives," high molecular weight components are not included in the resin components of this embodiment. The resin components in the resin composition of this embodiment preferably comprise polybutylene terephthalate resin and polycarbonate resin in total at 90% by mass or more, more preferably at 95% by mass or more, even more preferably at 98% by mass or more, and even more preferably at 99% by mass or more. Furthermore, the total content of the resin components in the resin composition is preferably at 72% by mass or more, more preferably at 75% by mass or more of the resin composition. The total content of the resin components in the resin composition is preferably 92% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less, and even more preferably 84% by mass or less, of the resin composition. By setting the content within this range, a molded product having a good balance of chemical resistance, impact resistance, and dimensional stability can be obtained.

[0027] <<Elastomer>> In this embodiment, in order to improve the impact resistance of the molded article, an elastomer is blended in addition to the resin component containing the polybutylene terephthalate resin. Examples of thermoplastic elastomers that are typically used to improve the impact resistance of molded articles include rubbery polymers and those obtained by copolymerizing rubbery polymers with compounds that react with the rubbery polymers.

[0028] Among the elastomers, an elastomer containing an epoxy group (an epoxy group-containing compound) is preferred. By including an elastomer containing an epoxy group, not only can the impact resistance of the molded article be increased, but also the adhesion of the water-based paint can be effectively improved.

[0029] A first embodiment of the epoxy group-containing elastomer is a copolymer obtained by copolymerizing an α-olefin, a glycidyl ester of an α,β-unsaturated acid, and, if necessary, an unsaturated monomer copolymerizable therewith. From the viewpoint of adhesion to aqueous coatings, the content of the glycidyl ester of an α,β-unsaturated acid is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, of the total copolymerization components. There is no particular upper limit, but from the viewpoint of handleability, it is preferably 20% by mass or less, more preferably 18% by mass or less, and even more preferably 16% by mass or less, of the total copolymerization components.

[0030] Examples of α-olefins include ethylene, propylene, butene-1, and pentene-1. Two or more of these may be used. Examples of glycidyl esters of α,β-unsaturated acids include glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, and glycidyl itaconate. Two or more of these may be used. Examples of vinyl monomers copolymerizable with the above components include vinyl ethers, vinyl esters such as vinyl acetate and vinyl propionate, acrylic and methacrylic acid esters such as methyl, ethyl, propyl, and butyl, acrylonitrile, and styrene. Two or more of these may be used.

[0031] Preferred examples of epoxy group-containing elastomers include ethylene / glycidyl methacrylate copolymers, ethylene / glycidyl methacrylate / vinyl acetate copolymers, ethylene / glycidyl methacrylate / alkyl acrylate copolymers, and ethylene / alkyl acrylate / vinyl acetate copolymers. In particular, ethylene / glycidyl methacrylate / alkyl acrylate (preferably butyl acrylate) copolymers are preferred from the viewpoint of excellent toughness and further improving the moist heat resistance and impact resistance of molded articles. Specific examples of epoxy group-containing elastomers are available from Arkema under the trade names "Rotadar" (registered trademark) AX8900 and AX8700.

[0032] Furthermore, elastomers other than the epoxy group-containing elastomer may also be added as appropriate. Examples of such elastomers include copolymers of ethylene and unsaturated carboxylic acid esters (e.g., ethylene-methacrylate copolymers, ethylene-butyl acrylate copolymers), copolymers of ethylene and aliphatic vinyl compounds, terpolymers of ethylene, propylene, and non-conjugated dienes, acrylic rubbers (e.g., polybutyl acrylate, poly(2-ethylhexyl acrylate), butyl acrylate-2-ethylhexyl acrylate copolymers), polybutadiene, polyisoprene, diene copolymers (e.g., styrene-butadiene copolymers, acrylonitrile-butadiene copolymers, acrylic-butadiene rubbers), copolymers of ethylene and α-olefins having 3 or more carbon atoms (e.g., ethylene-propylene copolymers, ethylene-butene copolymers, ethylene-octene copolymers), and silicone rubbers (e.g., polyorganosiloxane rubbers, IPN composite rubbers composed of polyorganosiloxane rubbers and polyalkyl(meth)acrylate rubbers).

[0033] Other elastomers include core-shell elastomers. The use of core-shell elastomers tends to provide excellent adhesion to thermoplastic resins such as polybutylene terephthalate resins due to the reactive compound contained in the core layer, resulting in increased welding strength. Examples of core-shell elastomers include those obtained by graft copolymerizing a monomer component onto a core polymer. The core is preferably a rubbery polymer, such as an acrylonitrile-acrylic rubbery polymer-styrene graft copolymer (ASA resin), a methyl methacrylate-acrylic rubbery polymer-styrene graft copolymer (MSA resin), a methyl methacrylate-acrylonitrile-acrylic rubbery polymer-styrene graft copolymer (MASA resin), and a polyorganosiloxane-containing rubbery polymer.

[0034] Specific examples of the monomer component graft copolymerizable with the core include aromatic vinyl compounds, vinyl cyanide compounds, (meth)acrylic acid ester compounds, (meth)acrylic acid compounds, epoxy group-containing (meth)acrylic acid ester compounds such as glycidyl (meth)acrylate, maleimide compounds such as maleimide, N-methylmaleimide, and N-phenylmaleimide; α,β-unsaturated carboxylic acid compounds such as maleic acid, phthalic acid, and itaconic acid, and anhydrides thereof (for example, maleic anhydride, etc.).

[0035] Specific examples of rubber polymers, aromatic vinyl compounds, vinyl cyanide compounds, and (meth)acrylic acid ester compounds are described in paragraphs 0042 to 0046 of JP 2019-059813 A, the contents of which are incorporated herein by reference.

[0036] The elastomer preferably has a melt flow rate (MFR) of 0.1 to 50 g / 10 min, more preferably 0.5 to 30 g / 10 min, measured at 190°C under a load of 2.16 kgf in accordance with JIS K 7210. By setting the MFR within the above range, there is a tendency for impact resistance to be improved while appearance defects are more effectively suppressed.

[0037] The content of the elastomer in the resin composition of this embodiment is 2 parts by mass or more, preferably 3 parts by mass or more, more preferably 4 parts by mass or more, even more preferably 5 parts by mass or more, and may be 6 parts by mass or more, or even 7 parts by mass or more, relative to 100 parts by mass of the resin component containing the polybutylene terephthalate resin. Furthermore, the content of the elastomer in the resin composition of this embodiment is 15 parts by mass or less, preferably 14 parts by mass or less, more preferably 13 parts by mass or less, even more preferably 12 parts by mass or less, and may be 11 parts by mass or less, 10 parts by mass or less, 9 parts by mass or less, or even 8 parts by mass or less, relative to 100 parts by mass of the resin component containing the polybutylene terephthalate resin. By setting the content of the elastomer within the above range, the toughness and impact resistance of the resulting molded product can be further improved without reducing the conductivity required for electrostatic coating. The resin composition of this embodiment may contain only one type of elastomer, or may contain two or more types. When two or more types of elastomers are contained, the total amount is preferably within the above range.

[0038] <<Hydroxyl Group-Containing Compound>> The hydroxyl group-containing compound used in this embodiment is １When analyzed by H NMR, the hydroxyl group concentration, expressed as the ratio of the peak area attributable to hydroxyl groups to the total peak area, expressed as [(peak area attributable to hydroxyl groups / total peak area) × 100], is in the range of 0.5 to 15.0%. In this embodiment, such a hydroxyl group-containing compound is used to improve the coating adhesion of an aqueous paint. The hydroxyl group-containing compound is not particularly limited as long as it satisfies the predetermined hydroxyl group concentration, but known hydroxyl group-containing oligomers and polymers are exemplified, with hydroxyl group-containing polymers being preferred. These hydroxyl group-containing oligomers and polymers preferably contain polar groups other than hydroxyl groups in an amount of 10 mol% or less of the hydroxyl groups. This configuration tends to more effectively demonstrate the effects of the present invention. Specific examples of hydroxyl group-containing compounds include polyalkylene glycols, polyvinyl alcohols, (meth)acrylic compounds (preferably (meth)acrylic polymers), and hyperbranched polyester resins. Among these, (meth)acrylic compounds are preferred, and (meth)acrylic polymers are particularly preferred, due to their suitable compatibility with polybutylene terephthalate resins. The hydroxyl group-containing compound used in this embodiment may be a crystalline compound or an amorphous compound, but is preferably an amorphous compound. In the case of a crystalline resin, it is presumed that the folded molecular chain structure of the crystalline portion makes it easier for hydroxyl groups to exist between molecules, thereby reducing the proportion of hydroxyl groups present in the surface layer portion. In the case of an amorphous resin, the molecular chain structure is randomized, increasing the proportion of hydroxyl groups present in the surface layer of the molded product, and paint adhesion tends to be more effectively exhibited. An amorphous compound refers to a compound that does not exhibit a clear melting point when measured by differential scanning calorimetry (DSC). When two or more hydroxyl group-containing compounds are used, it is preferable that at least one of the hydroxyl group-containing compounds contained in the resin composition is an amorphous compound. Furthermore, when two or more hydroxyl group-containing compounds are used, it is preferable that 80% by mass or more (even 90% by mass or more) of the hydroxyl group-containing compounds contained in the resin composition are amorphous compounds.

[0039] The hydroxyl group concentration in the hydroxyl group-containing compound is 0.5% or more, preferably 1.0% or more, and more preferably 1.2% or more. The upper limit of the hydroxyl group concentration is 15.0% or less, preferably 12.0% or less, more preferably 10.0% or less, even more preferably 9.0% or less, even more preferably 7.0% or less, even more preferably 5.0% or less, and even more preferably 3.0% or less. By setting the hydroxyl group concentration to 0.5% or less, the adhesion of water-based paints is improved. By setting the hydroxyl group concentration to 15.0% or less, or even 10.0% or less, compatibility with polybutylene terephthalate resins can be maintained at a moderate level, making it difficult for the hydroxyl group to remain inside the resin, thereby improving the adhesion and mechanical strength of water-based paints. Furthermore, by using a hydroxyl group-containing compound within the above range, the affinity of the molded body surface with water-based paints can be increased, and the adhesion of water-based paints during application can be improved. When the resin composition of the present embodiment contains two or more hydroxyl group-containing compounds, the hydroxyl group concentration is determined by calculating the hydroxyl group concentration of each compound and determining the average hydroxyl group concentration based on the mass ratio.

[0040] The hydroxyl group concentration in a hydroxyl group-containing compound is determined by dissolving the compound in a solvent and １ It can be calculated by the following formula, which expresses the ratio of the peak area derived from hydroxyl groups to the total peak area when analyzed by H NMR: Hydroxyl group concentration (%) = [(peak area derived from hydroxyl groups (hydroxyl proton integral value) / total peak area (total proton integral value)) × 100]. It is preferable that the solvent used is a good solvent in which the compound is sufficiently soluble. Examples of the solvent that can be used include dimethyl sulfoxide-d6, deuterated chloroform, deuterated tetrachloroethane, and deuterated methanol. When multiple hydroxyl compounds are used, it is expressed as the sum of the products of the ratio obtained by dividing the amount of each hydroxyl compound by the total amount of hydroxyl compounds and the concentrations of each hydroxyl compound. Example: When hydroxyl compound A and hydroxyl compound B are used, hydroxyl group concentration (%) = hydroxyl group concentration (%) of hydroxyl compound A / (parts by mass of hydroxyl compound A / parts by mass of all hydroxyl compounds) + hydroxyl group concentration (%) of hydroxyl compound B / (parts by mass of hydroxyl compound B / parts by mass of all hydroxyl compounds).

[0041] The acid value of the hydroxyl group-containing compound used in this embodiment is preferably 200 mgKOH / g or less, more preferably 100 mgKOH / g or less, even more preferably 50 mgKOH / g or less, even more preferably 30 mgKOH / g or less, even more preferably 15 mgKOH / g or less, and even more preferably 10 mgKOH / g or less. The lower limit of the acid value is usually 0 mgKOH / g or more. By setting the acid value to 200 mgKOH / g or less, the impact resistance of the resulting molded article tends to be further improved. When the resin composition of this embodiment contains two or more hydroxyl group-containing compounds, the acid value refers to the acid value of the mixture of hydroxyl group-containing compounds. The acid value is measured in accordance with JIS K0070-1992.

[0042] The weight-average molecular weight of the hydroxyl group-containing compound used in this embodiment is preferably 1,500 or more, more preferably 2,000 or more, and preferably 30,000 or less, more preferably 25,000 or less, even more preferably 20,000 or less, even more preferably 18,000 or less, and even more preferably 16,000 or less. By setting the weight-average molecular weight to 1,500 or more, separation on the surface of the molded body can be suppressed, effectively preventing deterioration of the appearance of the molded body and mold contamination. Furthermore, by setting the weight-average molecular weight to 30,000 or less, the hydroxyl group-containing compound is less likely to remain inside the molded body, thereby further improving the adhesion of the aqueous paint. In other words, by using a hydroxyl group-containing compound within the preferred range, the hydroxyl group-containing compound can adequately float to the surface of the molded body, more effectively improving the adhesion of the aqueous paint during application. In this embodiment, the hydroxyl group-containing compound is preferably a blend of one having a weight-average molecular weight of 1,500 to 5,000 (preferably 2,000 or more, and preferably 4,000 or less, more preferably 3,000 or less) and one having a weight-average molecular weight of 10,000 to 30,000 (preferably 11,000 or more, more preferably 12,000 or more, even more preferably 13,000 or more, and preferably 27,000 or less, more preferably 24,000 or less, even more preferably 21,000 or less, even more preferably 18,000 or less, and even more preferably 16,000 or less). By using such a composition, the effects of the present invention tend to be more effectively exhibited. In particular, in the resin composition of the present embodiment, the mass ratio of the hydroxyl group-containing compound having a weight average molecular weight of 1,500 to 5,000 to the hydroxyl group-containing compound having a weight average molecular weight of 10,000 to 30,000 is preferably 1:1 to 1:4, and more preferably 1:1 to 1:3.

[0043] In this embodiment, the ratio of the weight average molecular weight of the polybutylene terephthalate resin to the weight average molecular weight of the hydroxyl group-containing compound (weight average molecular weight of polybutylene terephthalate resin / weight average molecular weight of hydroxyl group-containing compound) is preferably 40 / 1 to 5 / 1, and more preferably 40 / 1 to 8 / 1. By making the ratio equal to or greater than the lower limit, delamination near the gate tends to be suppressed, resulting in a more excellent appearance. By making the ratio equal to or less than the upper limit, the flowability during molding tends to be more excellent.

[0044] The content of the hydroxyl group-containing compound used in this embodiment is 3 parts by mass or more, preferably 4 parts by mass or more, and more preferably 5 parts by mass, per 100 parts by mass of the resin component containing the polybutylene terephthalate resin. Depending on the application, it may be 6 parts by mass or more, 7 parts by mass or more, 8 parts by mass or more, or 10 parts by mass or more. The content of the hydroxyl group-containing compound used in this embodiment is 20 parts by mass or less, more preferably 18 parts by mass or less, per 100 parts by mass of the resin component containing the polybutylene terephthalate resin. Depending on the application, it may be 16 parts by mass or less, 14 parts by mass or less, 12 parts by mass or less, 10 parts by mass or less, 9 parts by mass or less, or 8 parts by mass or less. By setting the content of the hydroxyl group-containing compound within the above range, it is possible to further improve the adhesion of the aqueous paint without reducing impact resistance. The resin composition of this embodiment may contain only one type of hydroxyl group-containing compound, or may contain two or more types. When two or more types are contained, it is preferable that the total amount is within the above range.

[0045] <<Conductive Carbon>> The resin composition of this embodiment contains conductive carbon. By containing conductive carbon, the resistivity of the molded body decreases, making electrostatic coating possible. Examples of conductive carbon include carbon black (e.g., ketjen black, furnace black, channel black, acetylene black), graphene, graphite, fullerene, carbon nanocoil, carbon nanotube, and carbon fiber, with carbon black being preferred and ketjen black being more preferred.

[0046] The number average primary particle diameter of the conductive carbon used in this embodiment may be appropriately selected and determined, but is preferably 5 nm or more, more preferably 7 nm or more, and even more preferably 10 nm or more. The average particle diameter is preferably 60 nm or less, more preferably 55 nm or less, and even more preferably 50 nm. By setting the number average primary particle diameter within the above range, aggregation of the conductive carbon tends to be suppressed, and the appearance tends to be improved. The number average primary particle diameter of the conductive carbon can be determined using a transmission electron microscope. When the conductive carbon is not particulate, the average primary particle diameter refers to the average primary particle diameter when converted into particles of the same volume.

[0047] The DBP absorption amount of the conductive carbon used in this embodiment is 300 cm 3 There is no particular upper limit, but it is preferable that the 3 It is preferable that the DBP absorption is 300 cm 3 By adding an amount of the compound to the resin composition in an amount of 100 g or more, it is possible to impart good electrical conductivity to the resin composition with a smaller amount of the compound added. The DBP absorption amount can be measured in accordance with JIS K6217 (unit: cm 3 / 100g).

[0048] The nitrogen adsorption specific surface area of ​​the conductive carbon used in this embodiment is 600 m 2 / g or more is preferable, and 800m 2 There is no particular upper limit, but from the viewpoint of handling, it is preferable that the molecular weight is 1500 m / g or more. 2 / g or less, and 2 / g or less. 2 By making the specific surface area of ​​the molded article 100% by weight, it is possible to impart electrical conductivity to the molded article while suppressing deterioration of mechanical properties. The nitrogen adsorption specific surface area can be measured in accordance with JIS K6217 (unit: m 2 / g).

[0049] The pH of the conductive carbon used in this embodiment is not particularly limited, but is usually 2 or more, preferably 3 or more, and more preferably 4 or more. The pH is 10 or less, preferably 9 or less, and more preferably 8 or less.

[0050] The content of the conductive carbon used in this embodiment is 3 parts by mass or more, more preferably 4 parts by mass or more, and even more preferably 5 parts by mass or more, relative to 100 parts by mass of the resin component containing the polybutylene terephthalate resin. Depending on the application, it may be 6 parts by mass or more, 7 parts by mass or more, 8 parts by mass or more, or 10 parts by mass or more. Furthermore, the content of the conductive carbon is 20 parts by mass or less, more preferably 19 parts by mass or less, and even more preferably 18 parts by mass or less, relative to 100 parts by mass of the resin component containing the polybutylene terephthalate resin. Depending on the application, it may be 17 parts by mass or less, 16 parts by mass or less, 14 parts by mass or less, 12 parts by mass or less, 10 parts by mass or less, 9 parts by mass or less, or 8 parts by mass or less. By setting the content of the conductive carbon within the above range, it is possible to impart conductivity to the molded article while maintaining mechanical properties. The resin composition of this embodiment may contain only one type of conductive carbon, or may contain two or more types. When two or more types are contained, it is preferable that the total amount is within the above range.

[0051] <<Stabilizer>> The resin composition of this embodiment may contain a stabilizer such as an antioxidant. Use of a stabilizer can suppress decomposition due to transesterification of the polybutylene terephthalate resin and the polycarbonate resin, improving physical properties and appearance. Examples of stabilizers include phenol-based stabilizers, amine-based stabilizers, phosphorus-based stabilizers, and thioether-based stabilizers. In this embodiment, phosphorus-based stabilizers and / or phenol-based stabilizers are preferred, and it is more preferred to include both a phosphorus-based stabilizer and a phenol-based stabilizer. In particular, when a polycarbonate resin is used, it is preferred to add a phosphorus-based stabilizer.

[0052] Any known phosphorus stabilizer can be used. Specific examples include phosphorus oxoacids such as phosphoric acid, phosphonic acid, phosphorous acid, phosphinic acid, and polyphosphoric acid; metal acid pyrophosphates such as sodium acid pyrophosphate, potassium acid pyrophosphate, and calcium acid pyrophosphate; phosphates of Group 1 or Group 2B metals such as potassium phosphate, sodium phosphate, cesium phosphate, and zinc phosphate; organic phosphate compounds, organic phosphite compounds, and organic phosphonite compounds, with organic phosphate compounds being particularly preferred.

[0053] As the phenol-based stabilizer, a hindered phenol-based stabilizer is preferably used. Specific examples of hindered phenol stabilizers 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], N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide], 2,4-dimethyl-6-(1-methylpentadecyl)phenol, diethyl[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphate, 3,3',3'',5,5',5''-hexa-tert-butyl-a,a',a''-(mesityle) 4,6-bis(octylthiomethyl)-o-cresol, ethylene bis(oxyethylene) bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], hexamethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,3,5-tris(3,5-di-tert-butyl 2,6-di-tert-butyl-4-(4,6-bis(octylthio)-1,3,5-triazin-2-ylamino)phenol, 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate, and the like.

[0054] 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. Specific examples of such hindered phenol stabilizers include "Irganox (registered trademark; the same applies hereinafter) 1010" and "Irganox 1076" manufactured by BASF, and "ADK STAB AO-50" and "ADK STAB AO-60" manufactured by ADEKA Corporation.

[0055] When a stabilizer is contained, its content is preferably in the range of 0.01 to 5 mass% of the resin composition. In particular, when the resin composition of this embodiment contains a phosphorus-based stabilizer, its content is preferably 0.05 parts by mass or more, more preferably 0.06 parts by mass or more, even more preferably 0.08 parts by mass or more, and even more preferably 0.10 parts by mass or more, and is preferably 2 parts by mass or less, more preferably 1.5 parts by mass or less, even more preferably 1.0 parts by mass or less, even more preferably 0.7 parts by mass or less, even more preferably 0.5 parts by mass or less, even more preferably 0.3 parts by mass or less, even more preferably 0.2 parts by mass or less, and especially more preferably 0.15 parts by mass or less, per 100 parts by mass of the resin component. In particular, when the resin composition of this embodiment contains a phenolic stabilizer, the content thereof is preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, even more preferably 0.25 parts by mass or more, and even more preferably 0.3 parts by mass or more, per 100 parts by mass of the resin component. It is also preferable that the content be 2 parts by mass or less, more preferably 1.5 parts by mass or less, even more preferably 1.0 parts by mass or less, even more preferably 0.7 parts by mass or less, and even more preferably 0.5 parts by mass or less. Furthermore, when a phosphorus-based stabilizer and a phenolic stabilizer are used in combination, the mass ratio of phosphorus-based / phenolic is preferably 1 / 0.5 to 5. The resin composition of this embodiment may contain only one type of stabilizer, or two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0056] <<Other Additives>> The resin composition of the present embodiment may contain resin additives other than those described above. Specifically, the resin composition may contain a mold release agent (polyethylene wax, oxidized polyethylene wax, silicone oil, fluorine-based resin, fatty acid, fatty acid ester, fatty acid metal salt, etc.), a flame retardant (phosphorus-based flame retardant, halogen-based flame retardant, organometallic flame retardant, etc.), an internal lubricant (fatty acid metal salt, polyethylene wax, etc.), a reinforcing material (carbon fiber, glass fiber, talc, mica, etc.), a dye, a weather resistance improver, a nucleating agent, a plasticizer, a flowability improver, etc.

[0057] When other components are contained, the total content thereof is preferably in the range of 0.01 to 10 mass% of the resin composition. The resin composition of this embodiment is prepared so that the total of the polybutylene terephthalate resin, polycarbonate resin, elastomer, hydroxyl group-containing compound, conductive carbon, and other components that are optionally blended together is 100 mass%. The resin composition of this embodiment is prepared so that the total of the polybutylene terephthalate resin, polycarbonate resin, elastomer, hydroxyl group-containing compound, conductive carbon, and other components that are optionally blended together is 100 mass%. Furthermore, the total of the polybutylene terephthalate resin, polycarbonate resin, elastomer, hydroxyl group-containing compound, and conductive carbon preferably accounts for 90 mass% or more of the resin composition, more preferably 94 mass% or more, and even more preferably 96 mass% or more. Furthermore, the total of the polybutylene terephthalate resin, polycarbonate resin, elastomer, hydroxyl group-containing compound, conductive carbon, stabilizer, and mold release agent preferably accounts for 95% by mass or more of the resin composition, more preferably 97% by mass or more, and even more preferably 99% by mass or more.

[0058] <Method for producing resin composition> The method for producing the resin composition of this embodiment is not limited to a specific method, but examples include a method in which components such as a polybutylene terephthalate resin, a polycarbonate resin, an elastomer, a hydroxyl group-containing compound, and conductive carbon are mixed together and then melted and kneaded. The melting and kneading method can be a method commonly used for thermoplastic resins.

[0059] Examples of melt-kneading methods include uniformly mixing the essential components described above and other components, if necessary, using a Henschel mixer, ribbon blender, V-type blender, tumbler, or the like, followed by melt-kneading using a single- or multi-screw kneading extruder, roll, Banbury mixer, Labo Plastomill (Brabender), or the like. When a reinforcing agent is added, feeding it from a side feeder in the kneading extruder is preferred, as this prevents breakage of the reinforcing agent and allows for dispersion. The melt-kneading temperature and kneading time can be selected depending on the types of components constituting the resin component, the ratio of the components, the type of melt-kneading machine, and the like. However, the melt-kneading temperature is preferably in the range of 200 to 300°C. By keeping the temperature at 300°C or below, thermal degradation of each component is less likely to be a problem, and the physical properties of the resulting molded product tend to be improved, as well as the appearance.

[0060] <Volume Resistivity> The resin composition of the present embodiment was molded into a test piece with a thickness of 3 mm, and the volume resistivity measured in accordance with IEC 60093 was 1.0 × 10 １４ It is preferably Ω cm or less, and 1.0 × 10 １２ It is more preferable that the viscosity is less than Ω cm. There is no particular lower limit, but it is preferably 1.0 × 10 １０ By setting the volume resistivity of the resin composition within the above range, electrostatic coating becomes easier.

[0061] <Method for manufacturing a molded article> The molded article of this embodiment is formed from the resin composition of this embodiment. The method for manufacturing the molded article in this embodiment is not particularly limited, and any molding method commonly used for resin compositions can be used. Examples include injection molding, ultra-high speed injection molding, injection compression molding, two-color molding, gas-assisted or other hollow molding methods, molding using an insulated mold, molding using a rapidly heated mold, foam molding (including supercritical fluid), insert molding, IMC (in-mold coating molding) molding, extrusion molding, sheet molding, thermoforming, rotational molding, laminate molding, press molding, blow molding, and the like. A molding method using a hot runner system can also be used.

[0062] <Applications> The resin composition and molded article of the present embodiment are suitable for a wide range of applications, such as interior and exterior parts for vehicles, aircraft, etc., electrical, electronic, and office automation equipment parts, mobile phones, machine parts, building materials, and leisure goods and miscellaneous goods.

[0063] Specifically, examples of automobile exterior parts include outer handles, door mirror stays, fenders, garnishes, bumpers, roof rails, and wiper arms, while examples of automobile interior parts include inner handles, center consoles, instrument panels, assist grips, and seat belt stoppers.

[0064] Examples of railway vehicle parts include table arms, handrails, and assist grips, while examples of electrical parts include shaver frames, hair dryers, refrigerator handles and pull handles, microwave oven doors, handles for portable MD systems, headphone arms, and housings for electric screwdrivers. Examples of building material parts include door handles, crescents, and French slats.

[0065] The resin composition of this embodiment can be electrostatically coated with a water-based paint, and is therefore used to form molded articles to be electrostatically coated with a water-based paint. The resin composition and molded articles of this embodiment are particularly suitable for use in automotive exterior parts, such as fuel oil cap parts. Examples of water-based paints include water-based urethane paints and water-based acrylic paints, and are particularly suitable for water-based urethane paints. This is presumably because residual isocyanate, a urethane raw material for water-based urethane paints, reacts with the hydroxyl groups of hydroxyl-containing compounds to further improve adhesion. That is, this embodiment makes it possible to provide a molded article having a paint layer, which comprises the molded article of this embodiment and a water-based paint layer applied (preferably electrostatically) to its surface. A kit of the resin composition of this embodiment and a water-based urethane paint is also preferably used. This kit is particularly suitable for use as a kit for fuel oil caps.

[0066] The present invention will be explained in more detail below with reference to examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be changed as appropriate 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.

[0067] <Raw materials used>

[0068] <Measurement of hydroxyl group concentration in hydroxyl group-containing compound> 14.2 g of the hydroxyl group-containing compound was dissolved in 0.5 mL of dimethyl sulfoxide-d6, and １ The hydroxyl group concentration was calculated using the following formula, which represents the ratio of the peak area derived from hydroxyl groups to the total peak area when analyzed by H NMR (AVANCE III): Hydroxyl group concentration (%) = [(peak area derived from hydroxyl groups (integrated value of hydroxyl group protons) / total peak area (integrated value of total protons)) × 100]

[0069] When multiple hydroxyl compounds are used, the concentration is expressed as the sum of the product of the amount of each hydroxyl compound divided by the total amount of hydroxyl compounds and the concentration of each hydroxyl compound. Example: When hydroxyl compound A and hydroxyl compound B are used, hydroxyl concentration (%) = hydroxyl concentration (%) of hydroxyl compound A / (parts by mass of hydroxyl compound A / parts by mass of all hydroxyl compounds) + hydroxyl concentration (%) of hydroxyl compound B / (parts by mass of hydroxyl compound B / parts by mass of all hydroxyl compounds).

[0070] Examples 1 to 4, Comparative Examples 1 to 6 <Compounds> Each component was weighed out so as to obtain the composition shown in the table below (each component is in parts by mass), and after uniformly mixing in a tumbler, the mixture was supplied to a twin-screw extruder ("TEX30α" manufactured by The Japan Steel Works, Ltd., L / D = 42) and kneaded under conditions of a screw rotation speed of 200 rpm, a discharge rate of 30 kg / hour, and a barrel temperature of 250°C. The molten resin extruded in the form of strands was quenched in a water tank and pelletized using a pelletizer to obtain pellets of the resin composition.

[0071] <Tensile Break Strength (MPa), Tensile Break Elongation (%)> The pellets obtained by the above-mentioned production method were dried at 120°C for 6 hours, and then injection molded using an injection molding machine (clamping force 85T) manufactured by The Japan Steel Works, Ltd. under conditions of a cylinder temperature of 250°C and a mold temperature of 80°C to mold ISO3167:93A type test specimens (hereinafter referred to as "ISO test specimens"). In accordance with ISO-527, the tensile break strength (unit: MPa) and tensile break elongation (unit: %) were measured using the ISO test specimens obtained above.

[0072] <Ultimate Flexural Strength (MPa) and Flexural Modulus (MPa)> Using a rectangular test piece of 80 mm × 10 mm × 4 mmt prepared by machining the parallel portion of the ISO test piece, the ultimate flexural strength (unit: MPa) and flexural modulus (unit: MPa) were measured in accordance with ISO-178 under an environment of a temperature of 23°C and a humidity of 50%.

[0073] <Notched Charpy impact strength (kJ / m ２)> The ISO test specimen obtained above was machined in accordance with ISO-179-1 and ISO179-2 to remove the gripping portions at both ends and to form a notch in the center to form a notched Charpy impact test specimen. The notched Charpy impact strength (unit: kJ / m) at 23°C was measured for the obtained notched Charpy impact test specimen as an evaluation of impact resistance in accordance with ISO-179-1 and ISO179-2. ２ ) was measured.

[0074] <Strength evaluation> A: Tensile breaking strength of 50 MPa or more, maximum bending strength of 75 MPa or more, notched Charpy impact strength of 12 kJ / m ２ B: Does not satisfy the conditions of A, and has a tensile strength of 45 MPa or more, a maximum bending strength of 70 MPa or more, and a notched Charpy impact strength of 10 kJ / m ２ C: Neither A nor B is satisfied.

[0075] <Deflection temperature under load (°C)> In accordance with ISO-75-1, the deflection temperature under load (unit: °C) was measured using a rectangular test piece of 80 mm × 10 mm × 4 mmt that was prepared by machining the parallel portion of the above ISO test piece.

[0076] <Volume Resistivity> The pellets obtained by the above-mentioned production method were dried at 120°C for 6 hours, and then injection molded using an injection molding machine ("NEX80" manufactured by Nissei Plastic Industrial Co., Ltd.) at a cylinder temperature of 260°C and a mold temperature of 80°C to mold flat test specimens of 100 mm x 100 mm x 3 mm. The volume resistivity of the test specimens obtained by the above-mentioned molding method was measured in accordance with IEC 60093. The unit of volume resistivity was expressed in Ω cm. A resistivity meter, part number R8340A manufactured by Advantest Corporation, was used to measure the volume resistivity.

[0077] <Conductivity evaluation> A: Volume resistivity is 1.0 × 10 １２ B: Volume resistivity is less than 1.0 × 10 １２ Ω・cm or more 1.0×10 １４ Ω・cm or less C: Volume resistivity is 1.0×10 １４ Ω・cm super

[0078] <Paintability> The surface of a 100 mm x 100 mm x 2 mm test piece was wiped with isopropyl alcohol, degreased, and then coated with a standard automotive body paint (manufactured by BASF) and baked at 140°C for 20 minutes. After baking, a 100-square grid peel test was performed according to JIS K5600. Using a utility knife, 11 vertical and horizontal cuts were made at 2 mm intervals on the painted surface, transparent adhesive tape was applied to the cuts, and the tape was rubbed with a fingertip to adhere. Within 5 minutes, the transparent adhesive tape was quickly peeled upward. This was repeated three times in both the vertical and horizontal directions, and the number of squares with paint remaining on the painted surface was recorded.

[0079] <Painting evaluation> A: No peeling of the squares during the paintability test B: 85 or more squares with paint remaining during the paintability test C: Less than 85 squares with paint remaining during the paintability test

[0080]

[0081]

[0082] As is clear from the above results, the resin composition of this embodiment had excellent paint adhesion with water-based paint. Furthermore, because it also had low volume resistivity, it was found to be suitable for applications such as fuel caps that require electrostatic painting. Furthermore, molded articles obtained from the resin composition of this embodiment also had excellent mechanical strength and heat resistance.

Claims

1. In 100 parts by mass of a resin component containing polybutylene terephthalate resin, 2 to 15 parts by mass of elastomer, 3 to 20 parts by mass of a hydroxyl group-containing compound, Contains 3 to 20 parts by mass of conductive carbon, The hydroxyl group-containing compound is １ A resin composition in which the hydroxyl group concentration, expressed as [(peak area derived from hydroxyl groups / total peak area) × 100], which is the ratio of the peak area derived from hydroxyl groups to the total peak area when analyzed by 1H NMR, is in the range of 0.5 to 15.0%.

2. The resin composition according to claim 1, wherein the resin component further comprises a polycarbonate resin.

3. The resin composition according to claim 2, further comprising 0.05 to 2 parts by mass of a phosphorus-based stabilizer per 100 parts by mass of the resin component.

4. The resin composition according to any one of claims 1 to 3, wherein the intrinsic viscosity of the polybutylene terephthalate resin is 1.00 to 1.50 dL / g.

5. The resin composition according to any one of claims 1 to 3, wherein the elastomer comprises an epoxy group-containing compound.

6. The resin composition according to any one of claims 1 to 3, wherein the weight-average molecular weight of the hydroxyl group-containing compound is 1,500 to 30,000.

7. The resin composition according to any one of claims 1 to 3, wherein the hydroxyl group-containing compound comprises a (meth)acrylic compound.

8. The resin composition according to any one of claims 1 to 3, wherein the hydroxyl group-containing compound is an amorphous compound.

9. The resin composition according to any one of claims 1 to 3, wherein the hydroxyl group concentration of the hydroxyl group-containing compound is in the range of 0.5 to 10.0%.

10. A resin composition according to any one of claims 1 to 3, used for forming a molded article to which a water-based paint is electrostatically applied.

11. The resin component further comprises a polycarbonate resin, The resin component is further comprising 100 parts by mass of the aforementioned resin component, plus 0.05 to 2 parts by mass of a phosphorus-based stabilizer. The intrinsic viscosity of the polybutylene terephthalate resin is 1.00 to 1.50 dL / g. The elastomer contains an epoxy group-containing compound, The weight-average molecular weight of the hydroxyl group-containing compound is 1,500 to 30,000. The hydroxyl group-containing compound includes a (meth)acrylic compound, The hydroxyl group-containing compound is an amorphous compound. The hydroxyl group concentration of the hydroxyl group-containing compound is in the range of 0.5 to 10.0%. Water-based paints are used in the formation of molded bodies that are electrostatically coated. The resin composition according to claim 1.

12. A molded article formed from the resin composition according to any one of claims 1 to 3 and 11.

13. The molded body according to claim 12, which is a fuel oil port cap.