Resin composition, pellet, and molded article

Abstract

To provide a resin composition, a pellet, and a molded article that exhibit superior thermal conductivity in an in-plane direction.SOLUTION: A resin composition comprising (A) a thermoplastic resin, (B) expanded graphite, and (C) aluminum powder, the content of the thermoplastic resin (A) being 50-92 vol%, the content of the expanded graphite (B) being 5-30 vol%, the content of the aluminum powder (C) being 3-20 vol%, and the total content of the expanded graphite (B) and the aluminum powder (C) being 8-50 vol%.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition, a pellet, and a molded article. [Background technology]

[0002] BACKGROUND ART In the past, in order to improve the thermal conductivity of a resin composition, it has been investigated to blend a filler into the resin composition (Patent Documents 1 to 3). Known thermoplastic resins used in thermally conductive resin compositions include polyamide resins, non-liquid crystal polyester resins, liquid crystal polymers, polyarylene sulfide resins, styrene resins, and polyester resins. Known fillers used in thermally conductive resin compositions include carbon fibers, metal fibers, silicon nitride whiskers, graphite, metal powder, metal flakes, metal oxides, carbon powder, graphite, carbon flakes, flaky carbon, mica, talc, boron nitride, aluminum nitride, silicon carbide, boron phosphide, titanium oxide, silicon oxide, barium sulfide, and alumina. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-146124 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-200986 [Patent Document 3] International Publication No. 2016 / 084397 Summary of the Invention [Problem to be solved by the invention]

[0004] As described above, various studies have been conducted on improving the thermal conductivity of resin compositions, and there is a particular demand for improving the thermal conductivity in the in-plane direction. Here, the in-plane thermal conductivity refers to the thermal conductivity in the flow direction of the resin composition during molding, for example, in an injection-molded product. The present invention aims to solve the above problems and to provide a resin composition, pellets, and molded articles having excellent thermal conductivity in the planar direction. [Means for solving the problem]

[0005] In view of the above-mentioned problems, the present inventors have conducted research and have found that the above-mentioned problems can be solved by blending expanded graphite and aluminum powder with a thermoplastic resin and adjusting the ratio of these. Specifically, the above problems were solved by the following means. <1> A resin composition comprising (A) a thermoplastic resin, (B) expanded graphite, and (C) aluminum powder, The content of the (A) thermoplastic resin is 50 to 92% by volume, The content of the (B) expanded graphite is 5 to 30% by volume, the content of the (C) aluminum powder is 3 to 20% by volume, A resin composition in which the total content of the (B) expanded graphite and the (C) aluminum powder is 8 to 50% by volume. <2> The average particle size D50 of the (B) expanded graphite is 30 to 1000 μm, and the average particle size D50 of the (C) aluminum powder is 1 to 300 μm. <1> The resin composition according to claim 1. <3> the average particle size D50 of the (B) expanded graphite is larger than the average particle size D50 of the (C) aluminum powder; <1> or <2> The resin composition according to claim 1. <4> the difference between the average particle size D50 of the (B) expanded graphite and the average particle size D50 of the (C) aluminum powder is 100 to 350 μm; <1> ~ <3> The resin composition according to any one of the above. <5> The (A) thermoplastic resin includes a polyamide resin. <1> ~ <4> The resin composition according to any one of the above. <6> The (A) thermoplastic resin includes a bio-based polyamide resin. <1> ~ <5> The resin composition according to any one of the above. <7> The (A) thermoplastic resin contains a polyamide resin containing diamine units and dicarboxylic acid units, and 70 mol % or more of the diamine units are derived from xylylenediamine. <1> ~ <6> The resin composition according to any one of the above. <8> The volume ratio of the (B) expanded graphite to the (C) aluminum powder is 75:25 to 33:67. <1> ~ <7> The resin composition according to any one of the above. <9> The thermal conductivity in the plane direction of an injection-molded article of 100 mm × 100 mm × 2 mm formed from the resin composition is 7.0 to 20.0 W / (m K). <1> ~ <8> The resin composition according to any one of the above. <10> The thermal conductivity in the thickness direction of an injection-molded article of 100 mm × 100 mm × 2 mm formed from the resin composition is 1.2 to 10.0 W / (m·K) or more. <1> ~ <9> The resin composition according to any one of the above. <11> The specific gravity of the resin composition is 1.30 to 1.70 g / cm 3 That is, <1> ~ <10> The resin composition according to any one of the above. <12> The average particle size D50 of the (B) expanded graphite is 30 to 1000 μm, and the average particle size D50 of the (C) aluminum powder is 1 to 300 μm, the average particle size D50 of the (B) expanded graphite is larger than the average particle size D50 of the (C) aluminum powder, the difference between the average particle size D50 of the (B) expanded graphite and the average particle size D50 of the (C) aluminum powder is 100 to 350 μm; the (A) thermoplastic resin is a bio-based polyamide resin, the (A) thermoplastic resin contains a polyamide resin that contains diamine units and dicarboxylic acid units, and 70 mol % or more of the diamine units are derived from xylylenediamine; the volume ratio of the (B) expanded graphite to the (C) aluminum powder is 75:25 to 33:67; a thermal conductivity in the plane direction of a 100 mm × 100 mm × 2 mm injection-molded article formed from the resin composition is 7.0 to 20.0 W / (m K); a thermal conductivity in the thickness direction of a 100 mm × 100 mm × 2 mm injection-molded article formed from the resin composition is 1.2 to 10.0 W / (m K); The specific gravity of the resin composition is 1.30 to 1.70 g / cm 3 That is, <1> ~ <11> The resin composition according to any one of the above. <13> <1> ~ <12> A pellet of the resin composition according to any one of the above. <14> <1> ~ <12> A molded article formed from the resin composition according to any one of the above items. <15> <13> A molded article formed from the pellets according to claim 1. [Effects of the Invention]

[0006] The present invention makes it possible to provide a resin composition, pellets, and molded articles having excellent thermal conductivity in the planar direction. DETAILED DESCRIPTION OF THE INVENTION

[0007] 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, various physical properties and characteristic values ​​are those at 23°C unless otherwise specified. In addition, unless otherwise specified, the volume in this specification refers to the volume at 23°C and 1 atmosphere. 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.

[0008] 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.

[0009] The resin composition of the present embodiment is a resin composition containing (A) a thermoplastic resin, (B) expanded graphite, and (C) aluminum powder, characterized in that the content of the (A) thermoplastic resin is 50 to 92 volume %, the content of the (B) expanded graphite is 5 to 30 volume %, the content of the (C) aluminum powder is 3 to 20 volume %, and the total content of the (B) expanded graphite and the (C) aluminum powder is 8 to 50 volume %. By adopting such a configuration, the thermal conductivity of the obtained molded article in the planar direction can be improved. That is, when a thermoplastic resin, expanded graphite, and aluminum powder are melt-kneaded, the aluminum powder has a moderate hardness, which causes the expanded graphite to be crushed to a moderate degree. As a result, it is presumed that a conductive path is formed by the expanded graphite and aluminum powder in the resulting molded product. In particular, it is presumed that expanded graphite is thinner than flake graphite and therefore tends to be more easily crushed. As a result, it is presumed that the thermal conductivity in the planar direction is improved. In particular, the expanded graphite is crushed during melt-kneading, but the crushing is not uniform, and it exists in a distributed state in the molded product, which is presumed to form an excellent conductive path. In this specification, the term "plane direction" refers not only to injection-molded articles obtained by injection molding, but also to the direction along the resin flow direction when molding a resin composition, i.e., the direction in which expanded graphite is oriented.

[0010] <(A) Thermoplastic resin> The resin composition of the present embodiment contains a thermoplastic resin. The thermoplastic resin used in this embodiment is preferably selected from polyamide resin, polycarbonate resin, polyester resin, polyolefin resin, polypropylene resin, styrene-based resin, polyethylene resin, and acrylic resin. Among these, polyamide resin, polycarbonate resin, and styrene-based resin are preferred, polyamide resin and polycarbonate resin are more preferred, and polyamide resin is even more preferred. The thermoplastic resin (A) used in this embodiment may be a recycled thermoplastic resin product (including recovered products, material recycled products, chemical recycled products, etc.), a rejected product, or scrap material generated when molding a molded product from a resin composition.

[0011] <<Polyamide resin>> Polyamide resins are polymers whose constituent units are acid amides obtained by ring-opening polymerization of lactams, polycondensation of aminocarboxylic acids, or polycondensation of diamines and dibasic acids. Specific examples include polyamide 6, polyamide 11, polyamide 12, polyamide 46, polyamide 66, polyamide 610, polyamide 612, polyamide 6I, polyamide 6 / 66, polyamide 6T / 6I, polyamide 6 / 6T, polyamide 66 / 6T, polyamide 66 / 6T / 6I, polyamide MX, polytrimethylhexamethylene terephthalamide, polybis(4-aminocyclohexyl)methanedodecamide, polybis(3-methyl-4-aminocyclohexyl)methanedodecamide, and polyundecamethylenehexahydroterephthalamide. The "I" in the above text represents the isophthalic acid component, and the "T" represents the terephthalic acid component. Regarding polyamide resins, the description in paragraphs 0011 to 0013 of JP-A No. 2011-132550 can be referred to, the contents of which are incorporated herein by reference. The polyamide resin is preferably a bio-based polyamide resin.

[0012] The polyamide resin used in this embodiment is preferably a xylylenediamine-based polyamide resin containing diamine units and dicarboxylic acid units, with 70 mol % or more of the diamine units being derived from xylylenediamine. The diamine units of the xylylenediamine-based polyamide resin are more preferably derived from xylylenediamine (preferably paraxylylenediamine and / or metaxylylenediamine) at 75 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, still more preferably 95 mol% or more, and particularly preferably 99 mol% or more.

[0013] The xylylenediamine is preferably paraxylylenediamine and / or metaxylylenediamine. The xylylenediamine preferably contains 0 to 100 mol% metaxylylenediamine and 100 to 0 mol% paraxylylenediamine (however, the total of metaxylylenediamine and paraxylylenediamine does not exceed 100 mol%), more preferably 10 to 100 mol% metaxylylenediamine and 90 to 0 mol% paraxylylenediamine, even more preferably 50 to 100 mol% metaxylylenediamine and 0 to 50 mol% paraxylylenediamine, and even more preferably 60 to 100 mol% metaxylylenediamine and 40 to 0 mol% paraxylylenediamine. In the xylylenediamine-based polyamide resin, the total of paraxylylenediamine units and metaxylylenediamine units preferably accounts for 80 mol % or more, more preferably 85 mol % or more, even more preferably 90 mol % or more, still more preferably 95 mol % or more, still more preferably 98 mol % or more, and still more preferably 99 mol % or more of the diamine units. The upper limit of the total of paraxylylenediamine units and metaxylylenediamine units is 100 mol %.

[0014] Diamines other than metaxylylenediamine and paraxylylenediamine that can be used as raw diamine components for xylylenediamine-based polyamide resins include aliphatic diamines such as tetramethylenediamine, pentamethylenediamine, 2-methylpentanediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,2,4-trimethylhexamethylenediamine, and 2,4,4-trimethylhexamethylenediamine; 1,3-bis( Examples of the diamine include alicyclic diamines such as bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis(4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, bis(aminomethyl)decalin, and bis(aminomethyl)tricyclodecane; and diamines having an aromatic ring such as bis(4-aminophenyl)ether, paraphenylenediamine, and bis(aminomethyl)naphthalene. These diamines can be used alone or in combination of two or more.

[0015] On the other hand, the dicarboxylic acid units of the xylylenediamine-based polyamide resin are preferably derived from α,ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms (preferably sebacic acid) for a proportion of preferably 70 mol % or more, more preferably 75 mol % or more, even more preferably 80 mol % or more, even more preferably 90 mol % or more, still more preferably 95 mol % or more, and particularly preferably 99 mol % or more.

[0016] Examples of α,ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms that are suitable for use as the raw dicarboxylic acid component of xylylenediamine-based polyamide resins include aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, undecanedioic acid, and 1,12-dodecanedioic acid. These can be used alone or in combination of two or more. Among these, at least one of adipic acid, sebacic acid, and 1,12-dodecanedioic acid is preferred, as this ensures that the melting point of the polyamide resin falls within a range suitable for molding and processing. Adipic acid and / or sebacic acid are more preferred, with sebacic acid being even more preferred. Sebacic acid can be obtained as a naturally occurring component, and by using sebacic acid, a bio-based polyamide resin can be used as the thermoplastic resin.

[0017] Examples of dicarboxylic acid components other than those mentioned above include phthalic acid compounds such as isophthalic acid, terephthalic acid, and orthophthalic acid, and isomers of naphthalenedicarboxylic acid such as 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid, and these can be used alone or in combination of two or more.

[0018] In this embodiment, the polyamide resin preferably contains diamine units and dicarboxylic acid units, in which 70 mol % or more of the diamine units are derived from paraxylylenediamine and 70 mol % or more of the dicarboxylic acid units are derived from an α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms, and more preferably a xylylenediamine-based polyamide resin in which 90 mol % or more of the diamine units are derived from xylylenediamine and 90 mol % or more of the dicarboxylic acid units are derived from sebacic acid. Such xylylenediamine-based polyamide resins are preferred because they have a high degree of crystallinity, a high melting point, and excellent dimensional stability.

[0019] Although the xylylenediamine-based polyamide resin is primarily composed of diamine units and dicarboxylic acid units, other structural units are not completely excluded, and it goes without saying that it may contain structural units derived from lactams such as ε-caprolactam and laurolactam, and aliphatic aminocarboxylic acids such as aminocaproic acid and aminoundecanoic acid. Here, "major component" refers to the structural units constituting the xylylenediamine-based polyamide resin in which the total number of diamine units and dicarboxylic acid units is the largest among all structural units. In this embodiment, the total of the diamine units and dicarboxylic acid units in the xylylenediamine-based polyamide resin preferably accounts for 90% by mass or more of all structural units, more preferably 95% by mass or more, even more preferably 97% by mass or more, and even more preferably 99% by mass or more.

[0020] It is also preferable to use a polyamide resin produced using biomass raw materials (biomass polyamide resin) as the xylylenediamine-based polyamide resin, which can reduce the environmental impact. Bio-adipic acid can be used as a biomass raw material for xylylenediamine-based polyamide resins. Mass-balance certified (ISCC PLUS) adipic acid can also be used. Mass-balance certification means that the amount of renewable or bio-based raw materials used at each factory or production facility, and the amount of products produced or shipped are quantified, along with the quality, and guaranteed.

[0021] In the resin composition of this embodiment, the content of the xylylenediamine-based polyamide resin in 100 parts by mass of polyamide resin is preferably 90 parts by mass or more, more preferably 95 parts by mass or more, and even more preferably 97 parts by mass or more, and may be 100 parts by mass or less.

[0022] The melting point of the polyamide resin is preferably 150°C or higher, more preferably 250°C or higher, and even more preferably 280°C or higher, and is preferably 350°C or lower, more preferably 330°C or lower, and even more preferably 300°C or lower.

[0023] The lower limit of the number average molecular weight (Mn) of the polyamide resin is preferably 6,000 or more, more preferably 8,000 or more, and even more preferably 10,000 or more, and is preferably 100,000 or less, more preferably 50,000 or less. Within such ranges, the heat resistance, elastic modulus, dimensional stability, and moldability are improved.

[0024] <<Polycarbonate resin>> The polycarbonate resin is not particularly limited, and any of aromatic polycarbonate, aliphatic polycarbonate, and aromatic-aliphatic polycarbonate can be used. Among them, aromatic polycarbonate is preferred, and further, thermoplastic aromatic polycarbonate polymers or copolymers obtained by reacting an aromatic dihydroxy compound with phosgene or a diester of carbonic acid are more preferred.

[0025] Examples of aromatic dihydroxy compounds include 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), tetramethylbisphenol A, bis(4-hydroxyphenyl)-p-diisopropylbenzene, hydroquinone, resorcinol, and 4,4-dihydroxydiphenyl, with bisphenol A being preferred. Furthermore, for the purpose of preparing a highly flame-retardant composition, compounds in which one or more tetraalkylphosphonium sulfonates are bonded to the above aromatic dihydroxy compounds, or polymers or oligomers having a siloxane structure and containing phenolic OH groups at both ends, can be used.

[0026] Preferred examples of the polycarbonate resin used in this embodiment include polycarbonate resins derived from 2,2-bis(4-hydroxyphenyl)propane; and polycarbonate copolymers derived from 2,2-bis(4-hydroxyphenyl)propane and other aromatic dihydroxy compounds.

[0027] The method for producing the polycarbonate resin is not particularly limited, and in this embodiment, polycarbonate resins produced by any method, such as a phosgene method (interfacial polymerization method) or a melting method (ester interchange method), can be used. In addition, in this embodiment, polycarbonate resins produced by a general melting method production process followed by a process of adjusting the amount of OH groups in the terminal groups may also be used.

[0028] Furthermore, the polycarbonate resin used in this embodiment may be not only a polycarbonate resin as a virgin raw material, but also a polycarbonate resin regenerated from used products, that is, a so-called material-recycled polycarbonate resin.

[0029] For further details regarding the polycarbonate resin used in this embodiment, see, for example, the descriptions in paragraphs 0018 to 0066 of JP-A No. 2012-072338 and paragraphs 0011 to 0018 of JP-A No. 2015-166460, the contents of which are incorporated herein by reference.

[0030] <<Polyester resin>> Examples of polyester resins include polyethylene terephthalate resins and polybutylene terephthalate resins. As is well known, polyethylene terephthalate resins and polybutylene terephthalate resins are produced on a large scale by reacting terephthalic acid or ester with ethylene glycol or 1,4-butanediol, and are distributed on the market. In this embodiment, these commercially available resins can be used. Some commercially available resins contain copolymer components other than the terephthalic acid component and the ethylene glycol component or 1,4-butanediol component. In this embodiment, resins containing a small amount of copolymer component, typically 10% by mass or less, preferably 5% by mass or less, can also be used. The intrinsic viscosity of polyethylene terephthalate resin is usually 0.4 to 1.0 dL / g, and preferably 0.5 to 1.0 dL / g. When the intrinsic viscosity is equal to or greater than the lower limit, the mechanical properties of the resin composition are less likely to deteriorate, and when it is equal to or less than the upper limit, fluidity is easily maintained. Note that all intrinsic viscosities are measured at 30°C in a phenol / tetrachloroethane (1 / 1 mass ratio) mixed solvent. The intrinsic viscosity of the polybutylene terephthalate resin is usually 0.5 to 1.5 dL / g, and preferably 0.6 to 1.3 dL / g. If the intrinsic viscosity is equal to or greater than the lower limit, it is easy to obtain a resin composition with excellent mechanical strength. If the intrinsic viscosity is equal to or less than the upper limit, the resin composition does not lose its fluidity, and tends to have excellent moldability. In addition, the amount of terminal carboxyl groups is preferably 30 meq / g or less.

[0031] 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 but 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%. Reference is also made to paragraphs 0014 to 0022 of JP 2019-006866 A, which are incorporated herein by reference. In addition to the above, the polyester resin may be found in paragraphs 0013 to 0016 of JP-A-2010-174223, the contents of which are incorporated herein by reference. The resin composition used in the present embodiment may contain only one type of thermoplastic polyester resin, or may contain two or more types.

[0032] <<Styrene-based resin>> The styrene-based resin refers to at least one polymer selected from the group consisting of a styrene-based polymer made of a styrene-based monomer, a copolymer of a styrene-based monomer and another copolymerizable vinyl-based monomer, and a copolymer obtained by polymerizing a styrene-based monomer or a styrene-based monomer and another copolymerizable vinyl-based monomer in the presence of a rubber-based polymer, and among these, a copolymer with a rubber-based polymer is preferred.

[0033] Examples of rubbery polymers copolymerizable with styrene-based monomers include polybutadiene, polyisoprene, styrene-butadiene random copolymers and block copolymers, acrylonitrile-butadiene random copolymers and block copolymers, acrylonitrile-butadiene copolymers, copolymers of acrylic acid alkyl esters or methacrylic acid alkyl esters with butadiene, copolymers of ethylene and α-olefins such as polybutadiene-polyisoprene diene copolymers, ethylene-isoprene random copolymers and block copolymers, and ethylene-butene random copolymers and block copolymers, copolymers of ethylene and α,β-unsaturated carboxylic acid esters such as ethylene-methacrylate copolymers and ethylene-butyl acrylate copolymers, ethylene-propylene-non-conjugated diene terpolymers such as ethylene-vinyl acetate copolymers and ethylene-propylene-hexadiene copolymers, acrylic rubbers, and composite rubbers consisting of polyorganosiloxane rubber and polyalkyl acrylate or methacrylate rubber. For details of styrene-based resins, please refer to the descriptions in paragraphs 0019 to 0029 of JP 2015-166460 A, which are incorporated herein by reference. The resin composition used in the present embodiment may contain only one type of styrene-based resin, or may contain two or more types.

[0034] <<Other resins, etc.>> For further details about the thermoplastic resin, please refer to paragraphs 0011 to 0028 of JP 2014-074162 A, the contents of which are incorporated herein by reference.

[0035] A first embodiment of the thermoplastic resin of this embodiment is an embodiment in which 90% by mass or more (more preferably 95% by mass or more, and even more preferably 99% by mass or more) of the (A) thermoplastic resin is a polyamide resin (preferably a xylylenediamine-based polyamide resin). A second embodiment of the thermoplastic resin of this embodiment is an embodiment in which 90 mass % or more of the thermoplastic resin (A) is a polycarbonate resin. A third embodiment of the thermoplastic resin of this embodiment is an embodiment in which the thermoplastic resin (A) is 85 to 65 mass % polycarbonate resin and 15 to 35 mass % styrene resin (particularly rubber-based resin such as ABS resin). The total of the polycarbonate resin and the styrene resin is preferably 90 mass % or more of the thermoplastic resin. A fourth embodiment of the thermoplastic resin of this embodiment is an embodiment in which 85 to 65 mass % of the thermoplastic resin (A) is a polycarbonate resin and 15 to 35 mass % is a polyester resin (particularly polyethylene terephthalate). The total of the polycarbonate resin and the polyester resin is preferably 90 mass % or more of the thermoplastic resin. A fifth embodiment of the thermoplastic resin of this embodiment is an embodiment in which the thermoplastic resin (A) contains 15 to 45 mass% polybutylene terephthalate, 15 to 45 mass% isophthalic acid-modified polybutylene terephthalate, and 70 to 10 mass% polyamide resin (particularly aliphatic polyamide resin). The total of the polybutylene terephthalate, isophthalic acid-modified polybutylene terephthalate, and polyamide resin is preferably 90 mass% or more.

[0036] The resin composition of this embodiment contains (A) thermoplastic resin at 50 vol% or more, preferably 55 vol% or more, and at most 92 vol%, preferably 90 vol% or less, more preferably 85 vol% or less, even more preferably 80 vol% or less, still more preferably 70 vol% or less, and even more preferably 65 vol% or less, based on 100 vol% of the total volume of the resin composition. The resin composition of the present embodiment may contain only one type of (A) thermoplastic resin, or may contain two or more types. When two or more types are contained, the total amount is preferably in the above range.

[0037] <(B) Expanded graphite> The resin composition of the present embodiment contains expanded graphite. The expanded graphite is not particularly limited, and any known expanded graphite can be used as appropriate. The expanded graphite may be any graphite that expands when heated, and graphite (e.g., natural flaky graphite, pyrolytic graphite, kish graphite, etc.) with a compound or the like inserted between its layers can be suitably used. Examples of compounds that can be inserted between the layers of graphite include acids such as sulfuric acid and nitric acid, mixtures of these acids, nitrates, potassium dichromate, potassium chlorate, potassium permanganate, ammonium peroxodisulfate, sodium peroxodisulfate, hydrogen peroxide, and potassium permanganate. As such expanded graphite, commercially available products can be used as appropriate, such as the EXP-50 series and EXP-80 series manufactured by Fuji Graphite Industries Co., Ltd.; the 953240 series, 9550 series, and 9510 series manufactured by Ito Graphite Industries Co., Ltd.; the 5099SS-3 and 60CA-60 manufactured by Coal Chemical Co., Ltd.; and the SMF, EMF, SFF, and SS manufactured by Chuetsu Graphite Industries Co., Ltd. The expansion start temperature of the expanded graphite is not particularly limited, but is preferably 100 to 300°C, and more preferably 150 to 300°C. The "expansion start temperature" refers to the temperature at which a volume change occurs in the expanded graphite. The expansion ratio of the expanded graphite is not particularly limited, but may be, for example, 150% to 400%. The "expansion ratio" is calculated by dividing the volume of the expanded graphite after thermal expansion by the volume of the expanded graphite before thermal expansion and multiplying the result by 100. The particle size of the expanded graphite before expansion is not particularly limited, but may be, for example, 10 μm to 100 μm.

[0038] In the resin composition of this embodiment, the average particle size D50 of the (B) expanded graphite is preferably 30 μm or more, more preferably 50 μm or more, even more preferably 100 μm or more, even more preferably 200 μm or more, even more preferably 300 μm or more, even more preferably 400 μm or more, and is preferably 1000 μm or less, more preferably 700 μm or less, even more preferably 600 μm or less, even more preferably 500 μm or less, and even more preferably 450 μm or less. By setting the average particle size D50 to be equal to or greater than the lower limit, the thermal conductivity of the resin composition tends to be further improved. Meanwhile, by setting the average particle size D50 to be equal to or less than the upper limit, the strength and elastic modulus of a molded article obtained from the resin composition tend to be further improved. D50 means the median diameter, and is the value measured using a laser scattering particle size analyzer (the same applies to (C) aluminum powder, described below). When two or more types of (B) expanded graphite are contained, the D50 is the D50 of the mixture.

[0039] The content of (B) expanded graphite in the resin composition of this embodiment is preferably 5% by volume or more, more preferably 10% by volume or more, even more preferably 15% by volume or more, even more preferably 20% by volume or more, even more preferably 25% by volume or more, and preferably 30% by volume or less, based on 100% by volume of the resin composition. By making the content equal to or greater than the lower limit, the thermal conductivity of the resin composition tends to be further improved. Meanwhile, by making the content equal to or less than the upper limit, the strength of a molded article obtained from the resin composition tends to be further improved. The resin composition of the present embodiment may contain only one kind or two or more kinds of the following. When two or more kinds are contained, the total amount is preferably in the above range.

[0040] <(C) Aluminum powder> The resin composition of the present embodiment contains (C) aluminum powder. The aluminum powder is a powder containing aluminum as a main component, and typically, 90 mass % or more of the aluminum powder (C) is aluminum. The average particle size D50 of the aluminum powder (C) used in this embodiment is 1 to 300 μm. The average particle size D50 of the aluminum powder (C) is preferably 10 μm or more, more preferably 30 μm or more, even more preferably 50 μm or more, and even more preferably 70 μm or more, and is preferably 250 μm or less, and more preferably 200 μm or less. By setting the average particle size D50 to be equal to or greater than the lower limit, the thermal conductivity in the thickness direction of a molded article obtained from the resin composition tends to be further improved. Furthermore, by setting the average particle size D50 to be equal to or less than the upper limit, the strength of a molded article obtained from the resin composition tends to be further improved.

[0041] In this embodiment, it is preferable that the average particle size D50 of the (B) expanded graphite is larger than the average particle size D50 of the (C) aluminum powder. By adopting such a configuration, the thermal conductivity of the obtained molded article tends to be more effectively improved. The difference between the average particle size D50 of (B) expanded graphite and the average particle size D50 of (C) aluminum powder is preferably 100 μm or more, more preferably 150 μm or more, even more preferably 200 μm or more, even more preferably 250 μm or more, and is preferably 350 μm or less.

[0042] The content of (C) aluminum powder in the resin composition of this embodiment is, relative to 100% by volume of the resin composition, 3% by volume or more, preferably 6% by volume or more, more preferably 10% by volume or more, even more preferably 12% by volume or more, even more preferably 14% by volume or more, even more preferably 15% by volume or more, and 20% by volume or less, preferably 19% by volume or less, and more preferably 17% by volume or less. By setting the content at or above the lower limit, the thermal conductivity, strength, and elastic modulus of a molded article obtained from the resin composition tend to be further improved. Meanwhile, by setting the content at or below the upper limit, the specific gravity of the resin composition tends to be lower. The resin composition of the present embodiment may contain only one type of aluminum powder (C), or may contain two or more types. When two or more types are contained, the total amount is preferably in the above range.

[0043] In the resin composition of this embodiment, the total content of (B) expanded graphite and (C) aluminum powder is, relative to 100% by volume of the resin composition, 8% by volume or more, preferably 10% by volume or more, more preferably 15% by volume or more, even more preferably 25% by volume or more, even more preferably 35% by volume or more, and even more preferably 40% by volume or more, and is 50% by volume or less, preferably 45% by volume or less. By setting the total content at or above the lower limit, the thermal conductivity and elastic modulus of a molded article obtained from the resin composition tend to be further improved. By setting the total content at or below the upper limit, the specific gravity of the resin composition tends to be lower.

[0044] In the resin composition of the present embodiment, the volume ratio of the (B) expanded graphite to the (C) aluminum powder is preferably 75:25 to 33:67. Furthermore, when the total volume of the (B) expanded graphite and the (C) aluminum powder is taken as 100, the volume of the (B) expanded graphite is preferably 40 or more, more preferably 45, even more preferably 50, even more preferably 53, even more preferably 57 or more, and preferably 70 or less. By making the volume equal to or greater than the lower limit, the thermal conductivity of the resin composition tends to be further improved. Meanwhile, by making the volume equal to or less than the upper limit, the strength of the molded article obtained from the resin composition tends to be further improved.

[0045] <<Release Agent>> The resin composition of this embodiment may further contain a release agent. The release agent is primarily used to improve productivity during molding of the resin composition. Examples of the release agent include aliphatic carboxylic acid amides, aliphatic carboxylic acids, aliphatic carboxylic acid metal salts, esters of aliphatic carboxylic acids and alcohols, aliphatic hydrocarbon compounds having a number-average molecular weight of 200 to 15,000, polysiloxane-based silicone oils, ethylene bisstearic acid amide, and distearyl ketone.

[0046] For details about the release agent, please refer to the descriptions in paragraphs 0037 to 0042 of JP 2016-196563 A and paragraphs 0048 to 0058 of JP 2016-078318 A, the contents of which are incorporated herein by reference.

[0047] When a release agent is added, the content thereof is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and preferably 2.0% by mass or less, more preferably 1.5% by mass or less, based on 100% by mass of the resin composition. By adjusting the content within such ranges, it is possible to improve the mold releasability and prevent mold contamination during injection molding. The release agent may be used alone or in combination of two or more. When two or more types are used, it is preferable that the total amount is within the above range.

[0048] When a release agent is added, the lower limit of the content of the release agent relative to the resin composition is preferably 0.01% by volume or more, more preferably 0.1% by volume or more, and the upper limit is preferably 2.0% by volume or less, more preferably 1.0% by volume or less. By setting the content within such a range, it is possible to improve the mold releasability and prevent mold contamination during injection molding. The release agent may be used alone or in combination of two or more. When two or more types are used, it is preferable that the total amount is within the above range.

[0049] <Other ingredients> The resin composition of this embodiment may contain other components in addition to those described above. Examples of other components that may be added as needed include additives such as nucleating agents, antioxidants such as heat stabilizers and weather stabilizers, colorants, flame retardants, flame retardant assistants, anti-dripping agents, matting agents, UV absorbers, plasticizers, antistatic agents, color inhibitors, and anti-gelling agents. These additives may each be used alone or in combination of two or more. Details of these components include additives described in paragraphs 0047 to 0103 of International Publication No. 2021 / 241471, the contents of which are incorporated herein. The total amount of these other components in the resin composition of this embodiment is preferably less than 5% by mass of the resin composition, more preferably less than 3% by mass, and even more preferably less than 1% by mass. In the resin composition of the present embodiment, the total of (A) thermoplastic resin, (B) expanded graphite, and (C) aluminum powder and release agent preferably accounts for 90% by mass or more of the resin composition, more preferably 95% by mass or more, even more preferably 97% by mass or more, and even more preferably 99% by mass or more, and the upper limit may be 100% by mass or less. In the resin composition of the present embodiment, the total of (A) thermoplastic resin, (B) expanded graphite, and (C) aluminum powder and release agent preferably accounts for 90% by volume or more of the resin composition, more preferably 95% by volume or more, even more preferably 97% by volume or more, and even more preferably 99% by volume or more, and the upper limit may be 100% by volume or less.

[0050] <Physical properties of resin composition> The resin composition of the present embodiment preferably has excellent thermal conductivity when formed into a molded article. Specifically, the thermal conductivity in the planar direction of a 100 mm × 100 mm × 2 mm injection-molded article formed from the resin composition of this embodiment is preferably 7.0 W / (m·K) or more, more preferably 7.5 W / (m·K) or more, even more preferably 8.0 W / (m·K) or more, still more preferably 9.0 W / (m·K) or more, even more preferably 9.5 W / (m·K) or more, still more preferably 10.0 W / (m·K) or more, and particularly preferably 13.0 W / (m·K) or more; and although there is no particular upper limit, the required performance is sufficiently met even if the thermal conductivity is, for example, 20.0 W / (m·K) or less. Furthermore, the thermal conductivity in the thickness direction of a 100 mm × 100 mm × 2 mm injection-molded article formed from the resin composition of this embodiment is preferably 1.2 W / (m·K) or more, more preferably 1.5 W / (m·K) or more, even more preferably 1.8 W / (m·K) or more, still more preferably 2.0 W / (m·K) or more, even more preferably 3.0 W / (m·K) or more, and still more preferably 4.0 W / (m·K) or more. There is no particular upper limit, but the required performance will be fully satisfied even if the thermal conductivity is, for example, 10.0 W / (m·K) or less.

[0051] The resin composition of this embodiment has a specific gravity of 1.30 g / cm 3 It is preferable that the concentration is 1.35 g / cm or more. 3 More preferably, it is 1.40 g / cm or more. 3More preferably, it is 1.50 g / cm or more. 3 More preferably, it is 1.70 g / cm or more. 3 and preferably 1.65 g / cm 3 More preferably, it is: The resin composition of this embodiment preferably has a high flexural modulus. Specifically, when the resin composition is molded into a 4 mm thick ISO dumbbell test piece, the flexural modulus measured in accordance with ISO 178 is preferably 8 GPa or more, more preferably 9 GPa or more, and even more preferably 10 GPa or more. There is no particular upper limit to the flexural modulus, but for example, a flexural modulus of 30 GPa or less, or even 20 GPa or less, will sufficiently satisfy the required performance. The thermal conductivity, specific gravity and flexural modulus are measured according to the descriptions in the examples below.

[0052] <Method of manufacturing resin composition> In the present embodiment, the method for producing the resin composition is not particularly limited, and a wide variety of known methods for producing thermoplastic resin compositions can be employed. Specifically, the resin composition can be produced by pre-mixing the components using various mixers such as a tumbler or a Henschel mixer, and then melt-kneading them using a Banbury mixer, a roll, a Brabender mixer, a single-screw extruder, a twin-screw extruder, a kneader, or the like.

[0053] Alternatively, for example, the resin composition can be produced by not mixing the components in advance, or by mixing only some of the components in advance, feeding the mixture into an extruder using a feeder, and melt-kneading the mixture. Furthermore, for example, some of the components such as a colorant may be mixed in advance, fed to an extruder, and melt-kneaded to obtain a masterbatch composition, which may then be mixed again with the remaining components and melt-kneaded to produce pellets. Also, the glass fibers can be side fed.

[0054] <Applications of resin compositions and molded products> The molded article of this embodiment is formed from the resin composition or pellets of this embodiment. The method for producing the molded article of this embodiment is not particularly limited, but an example thereof is an injection-molded article produced by injection molding. For example, the molded product of this embodiment may be produced by melt-kneading the components and then directly molding the components by various molding methods, or by melt-kneading the components and pelletizing them, then melting them again and molding them by various molding methods.

[0055] The method for molding the molded article is not particularly limited, and any conventionally known molding method can be used, such as injection molding, injection compression molding, extrusion molding, profile extrusion, transfer molding, blow molding, gas-assisted blow molding, blow molding, extrusion blow molding, IMC (in-mold coating molding), rotational molding, multilayer molding, two-color molding, insert molding, sandwich molding, foam molding, and pressure molding.

[0056] The shape of the molded article of the present embodiment is not particularly limited and can be appropriately selected depending on the use and purpose of the molded article. Examples include plate-like, plate-like, rod-like, sheet-like, film-like, cylindrical, ring-like, circular, elliptical, gear-like, polygonal, irregular-shaped, hollow, frame-like, box-like, and panel-like shapes.

[0057] The application fields of the resin composition, pellets, and molded articles of the present embodiment are not particularly limited, and they are useful for high heat dissipation applications, metal replacement applications, ceramic replacement applications, electromagnetic wave shielding applications, high-precision parts (low dimensional change), high conductivity applications, etc. More specifically, electrical and electronic components such as various cases, gear cases, LED lamp-related parts, connectors, relay cases, switches, variable capacitor cases, optical pickup lens holders, optical pickup slide bases, various terminal boards, transformers, printed wiring boards, LCD panel frames, power modules and their housings, plastic magnets, semiconductors, LCD display parts, lamp covers for projectors etc., FDD carriages, FDD chassis, actuators, HDD parts such as chassis, computer-related parts, etc.; VTR parts, television parts, irons, hair dryers, rice cooker parts, microwave oven parts, acoustic parts, audio equipment parts such as audio, laser discs (registered trademark), compact discs, digital video discs, lighting parts, refrigerator parts, air conditioner parts and other household and office electrical appliance parts, office computer-related parts, telephone-related parts, facsimile-related parts, printer and copier-related parts such as print heads and transfer rolls, cleaning jigs, These materials are useful in a wide range of applications, including motor parts, optical equipment such as microscopes, binoculars, cameras, and watches, precision machinery parts, alternator terminals, alternator connectors, IC regulators, light dimmer potentiometer bases, motor core sealing materials, insulator materials, power seat gear housings, air conditioner thermostat bases, air conditioner panel switch boards, horn terminals, electrical component insulating plates, lamp housings, and ignition device cases. They are also useful in a wide range of applications, including housings for chip antennas and installed antennas in the information and communications field that require electromagnetic wave shielding, as well as partition boards that require high dimensional precision, electromagnetic wave shielding, and gas and liquid barrier properties, applications requiring thermal and electrical conductivity, and outdoor equipment and building materials. They are particularly useful in automotive parts, electrical and electronic parts, and thermal equipment parts, where weight reduction and freedom of shape are required and a metal replacement is highly desired.

Example

[0058] The present invention will be further specifically described with reference to the following examples. The materials, amounts used, ratios, treatment details, treatment procedures, etc. shown in the following examples can be appropriately changed as long as they do not depart from the gist of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. When the measuring instruments used in the examples are difficult to obtain due to being out of production numbers, etc., measurements can be made using other devices having equivalent performance.

[0059] 1. Raw materials The following raw materials were used.

Table 1

[0060] <Synthesis of PAMP10> Sebacic acid was heated and dissolved in a reaction vessel under a nitrogen atmosphere. Then, while stirring the contents, a mixed diamine with a molar ratio of 3:7 of p - xylylenediamine (manufactured by Mitsubishi Gas Chemical Company) and m - xylylenediamine (manufactured by Mitsubishi Gas Chemical Company) was gradually dropped under pressure (0.35 MPa) so that the molar ratio of diamine to sebacic acid became about 1:1, and the temperature was raised to 235°C. After the dropping was completed, the reaction was continued for 60 minutes to adjust the amount of components with a molecular weight of 1,000 or less. After the reaction was completed, the contents were taken out in a strand shape and pelletized with a pelletizer to obtain a polyamide resin (MP10).

[0061] 2. Examples 1 - 8, Comparative Examples 1 - 7 <Compound> The components shown in Table 1 were weighed as shown in Tables 2 - 4 (the unit of each component is parts by mass), blended, and charged from the root of a twin - screw extruder (manufactured by Shibaura Machine Co., Ltd., TEM26SS), melted, and kneaded to produce pellets of the resin composition. The temperature setting of the twin - screw extruder was 280°C.

[0062] <Flexural strength and flexural modulus> The thermoplastic resin pellets obtained by the above-mentioned manufacturing method were dried at 80°C for 12 hours, and then injection-molded into ISO dumbbell test pieces (4 mm thick) using an injection molding machine (Nissei Plastic Industrial Co., Ltd., "NEX140III") under the following conditions: cylinder temperature 290°C, mold temperature 130°C, and molding cycle 50 seconds. The flexural strength (unit: MPa) and flexural modulus (unit: GPa) of the above ISO dumbbell test pieces (4 mm thick) were measured in an environment of 23°C and 50% humidity in accordance with ISO 178. The results are shown in Tables 2 to 4.

[0063] <Specific gravity> The specific gravity of each molded product was measured by Archimedes' method. The unit of specific gravity is g / cm. 3 It was decided. For the measurements, an analytical balance AP324X manufactured by Shimadzu Corporation was used. The results are shown in Tables 2 to 4.

[0064] <Thermal conductivity> The thermoplastic resin pellets obtained by the above-mentioned manufacturing method were dried at 80°C for 12 hours, and then injection-molded into molded articles measuring 100 mm x 100 mm x 2 mm using an injection molding machine (Nissei Plastic Industrial Co., Ltd., "NEX140III") under conditions of a cylinder temperature of 290°C, a mold temperature of 130°C, and a molding cycle of 50 seconds. In accordance with ISO22007-2, the thermal conductivity (unit: W / m·K) was measured in the plane direction (direction of resin flow) and thickness direction of the test specimen. For the measurements, a hot disk method thermophysical property measuring device ("TPS-2500S" manufactured by Kyoto Electronics Manufacturing Co., Ltd.) was used. The unit of thermal conductivity is W / (m·K).

[0065] [Table 2]

[0066] [Table 3]

[0067] [Table 4]

[0068] As is clear from the above results, the resin composition of the present invention, when molded into a molded article, exhibited significantly high thermal conductivity in the planar direction. In addition, the resin composition of the present invention, when molded into a molded article, also exhibited high thermal conductivity in the thickness direction. Furthermore, when the resin composition of this embodiment was molded into a molded article, it maintained high bending properties, and in particular, the bending modulus was improved. Furthermore, the resin composition of this embodiment also had a relatively low specific gravity.

Claims

1. A resin composition comprising (A) a thermoplastic resin, (B) expanded graphite, and (C) aluminum powder, The content of the thermoplastic resin (A) is 50 to 92% by volume, The content of the (B) expanded graphite is 5 to 30% by volume, the content of the aluminum powder (C) is 3 to 20% by volume, A resin composition, wherein the total content of the (B) expanded graphite and the (C) aluminum powder is 8 to 50% by volume.

2. The resin composition according to claim 1, wherein the average particle diameter D50 of the (B) expanded graphite is 30 to 1000 μm, and the average particle diameter D50 of the (C) aluminum powder is 1 to 300 μm.

3. 2. The resin composition according to claim 1, wherein the average particle diameter D50 of the expanded graphite (B) is larger than the average particle diameter D50 of the aluminum powder (C).

4. The resin composition according to claim 1, wherein the difference between the average particle diameter D50 of the (B) expanded graphite and the average particle diameter D50 of the (C) aluminum powder is 100 to 350 μm.

5. The resin composition according to claim 1 , wherein the thermoplastic resin (A) comprises a polyamide resin.

6. The resin composition according to claim 1 , wherein the thermoplastic resin (A) comprises a bio-based polyamide resin.

7. The resin composition according to claim 1, wherein the thermoplastic resin (A) comprises a polyamide resin containing diamine units and dicarboxylic acid units, in which 70 mol% or more of the diamine units are derived from xylylenediamine.

8. 2. The resin composition according to claim 1, wherein the volume ratio of the (B) expanded graphite to the (C) aluminum powder is 75:25 to 33:

67.

9. The resin composition according to claim 1, wherein the thermal conductivity in the plane direction of an injection-molded product of 100 mm x 100 mm x 2 mm formed from the resin composition is 7.0 to 20.0 W / (m K).

10. The resin composition according to claim 1, wherein the thermal conductivity in the thickness direction of a 100 mm x 100 mm x 2 mm injection-molded product formed from the resin composition is 1.2 to 10.0 W / (m K) or more.

11. The specific gravity of the resin composition is 1.30 to 1.70 g / cm ３ The resin composition according to claim 1,

12. The average particle size D50 of the (B) expanded graphite is 30 to 1000 μm, and the average particle size D50 of the (C) aluminum powder is 1 to 300 μm, the average particle size D50 of the (B) expanded graphite is larger than the average particle size D50 of the (C) aluminum powder, the difference between the average particle size D50 of the (B) expanded graphite and the average particle size D50 of the (C) aluminum powder is 100 to 350 μm; the thermoplastic resin (A) is a bio-based polyamide resin, the thermoplastic resin (A) contains a polyamide resin containing diamine units and dicarboxylic acid units, in which 70 mol % or more of the diamine units are derived from xylylenediamine; the volume ratio of the (B) expanded graphite to the (C) aluminum powder is 75:25 to 33:67; the thermal conductivity in the plane direction of a 100 mm × 100 mm × 2 mm injection-molded article formed from the resin composition is 7.0 to 20.0 W / (m K); a thermal conductivity in the thickness direction of a 100 mm × 100 mm × 2 mm injection-molded article formed from the resin composition is 1.2 to 10.0 W / (m K); The specific gravity of the resin composition is 1.30 to 1.70 g / cm ３ The resin composition according to claim 1,

13. Pellets of the resin composition according to any one of claims 1 to 12.

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

15. A molded article formed from the pellets of claim 13.

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