JP7740972B2 - Thermoplastic resin composition and composite molded body in which metal molded body and resin molded body are joined - Google Patents

Description

The present invention relates to a thermoplastic resin composition suitable for molding a composite molded article in which a metal molded article and a resin molded article are bonded together, and to a composite molded article in which a metal molded article and a resin molded article are bonded together. More specifically, the present invention relates to a thermoplastic resin composition that has excellent adhesion to metals, exhibits little decrease in bond strength after heat cycle testing, and is highly durable, and to a composite molded article in which a metal molded article and a resin molded article are bonded together.

Metallic materials are used in various fields, including automobiles, electrical engineering, and electronics. Resin molded bodies are sometimes used as metal substitutes to reduce the weight of various parts. However, it is often difficult to replace all metal components with resin. In such cases, new composite parts can be manufactured by joining metal and resin molded bodies together. Technology is needed to join metal and resin molded bodies in an industrially advantageous manner with high bonding strength. Patent Document 1 describes a laser processing method for joining dissimilar materials (resins), including a step of laser scanning the metal surface in one scanning direction and a step of laser scanning in an intersecting scanning direction. Regarding the dissimilar materials, a thermoplastic resin containing glass fiber is also described. Patent Document 2 demonstrates that a composite molded body of a specific structure and a metal has high bonding strength. Patent Documents 3 and 4 demonstrate high bonding strength between metal and resin molded bodies, and describe resin molded bodies made from thermoplastic resins, thermosetting resins, and thermoplastic elastomers blended with carbon fiber, inorganic fiber, metal fiber, or organic fiber. However, none of these methods are sufficient for adhesion between metal and resin under the environmental temperature changes expected in actual use.

Patent No. 4020957 Japanese Patent Application Laid-Open No. 2020-066652 JP 2013-52669 A JP 2014-18995 A

The object of the present invention is to provide a thermoplastic resin composition that has excellent adhesion to metals, exhibits minimal reduction in bond strength after heat cycle testing, and is highly durable, as well as a resin-metal composite molded article made from the same.

As a result of extensive research to solve these problems, the inventors discovered that a composite molded product formed by bonding a resin molded product and a metal molded product formed from a thermoplastic resin composition obtained by blending an appropriate amount of expanded graphite into a thermoplastic resin can be obtained, and that the thermoplastic resin composition has excellent adhesion between the resin molded product and the metal molded product, minimal reduction in bond strength after heat cycle testing, and excellent durability, resulting in the present invention.

The present invention will now be described in detail.

<Component A: Thermoplastic Resin>
The thermoplastic synthetic resin is not particularly limited, and examples thereof include urethane resin, chlorotrifluoroethylene resin, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, vinylidene fluoride resin, ethylene-tetrafluoroethylene copolymer, ethylene-chlorofluoroethylene copolymer, vinyl chloride resin, vinylidene chloride resin, polyethylene, polypropylene, chlorinated polyolefin, water-crosslinked polyolefin, modified polyolefin, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, polystyrene, ABS resin, polyamide, methacrylic resin, polyacetal, polycarbonate resin, cellulose-based resin, polyvinyl alcohol, polyurethane elastomer, polyimide, polyetherimide, polyamideimide, ionomer resin, polyphenylene oxide, methylpentene polymer, polyarylsulfone, polyaryl ether, polyether ketone, polyphenylene sulfide, polysulfone, wholly aromatic polyester, polyethylene terephthalate, polybutylene terephthalate, thermoplastic polyester elastomer, and blends of various other polymeric substances. Among these, polycarbonate resins are preferred from the viewpoint of good mechanical properties.

The polycarbonate resin used in the present invention is obtained by reacting a dihydric phenol with a carbonate precursor. Examples of reaction methods include interfacial polymerization, melt transesterification, solid-phase transesterification of carbonate prepolymers, and ring-opening polymerization of cyclic carbonate compounds.

Representative examples of dihydric phenols used herein include hydroquinone, resorcinol, 4,4'-biphenol, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane (commonly known as bisphenol A), 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 2,2-bis(4-hydroxyphenyl)pentane, 4,4'-(p-phenylene) Examples of dihydric phenols include 4,4'-(m-phenylenediisopropylidene)diphenol, 4,4'-(m-phenylenediisopropylidene)diphenol, 1,1-bis(4-hydroxyphenyl)-4-isopropylcyclohexane, bis(4-hydroxyphenyl)oxide, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)sulfoxide, bis(4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl)ketone, bis(4-hydroxyphenyl)ester, bis(4-hydroxy-3-methylphenyl)sulfide, 9,9-bis(4-hydroxyphenyl)fluorene, and 9,9-bis(4-hydroxy-3-methylphenyl)fluorene. Preferred dihydric phenols are bis(4-hydroxyphenyl)alkanes, with bisphenol A being particularly preferred and widely used in terms of impact resistance.

In the present invention, in addition to bisphenol A-based polycarbonate resins, which are general-purpose polycarbonate resins, it is also possible to use special polycarbonate resins produced using other dihydric phenols as Component A. For example, polycarbonate resins (homopolymers or copolymers) using 4,4'-(m-phenylenediisopropylidene)diphenol (hereinafter sometimes abbreviated as "BPM"), 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane (hereinafter sometimes abbreviated as "Bis-TMC"), 9,9-bis(4-hydroxyphenyl)fluorene, and 9,9-bis(4-hydroxy-3-methylphenyl)fluorene (hereinafter sometimes abbreviated as "BCF") as part or all of the dihydric phenol component are suitable for applications where dimensional change due to water absorption and dimensional stability are particularly strict requirements. These dihydric phenols other than BPA are preferably used in an amount of 5 mol% or more, and especially 10 mol% or more, of the total dihydric phenol components that make up the polycarbonate resin. In particular, when high rigidity and better hydrolysis resistance are required, it is particularly suitable for component A that makes up the resin composition to be a copolymer polycarbonate resin of the following (1) to (3).

(1) A copolymer polycarbonate resin in which, based on 100 mol% of the dihydric phenol component constituting the polycarbonate resin, BPM is 20 to 80 mol% (more preferably 40 to 75 mol%, even more preferably 45 to 65 mol%) and BCF is 20 to 80 mol% (more preferably 25 to 60 mol%, even more preferably 35 to 55 mol%).
(2) A copolymer polycarbonate resin in which, based on 100 mol% of the dihydric phenol component constituting the polycarbonate resin, BPA accounts for 10 to 95 mol% (more preferably 50 to 90 mol%, even more preferably 60 to 85 mol%) and BCF accounts for 5 to 90 mol% (more preferably 10 to 50 mol%, even more preferably 15 to 40 mol%).
(3) A copolymer polycarbonate resin in which, based on 100 mol% of the dihydric phenol component constituting the polycarbonate resin, BPM accounts for 20 to 80 mol% (more preferably 40 to 75 mol%, even more preferably 45 to 65 mol%) and Bis-TMC accounts for 20 to 80 mol% (more preferably 25 to 60 mol%, even more preferably 35 to 55 mol%).

These special polycarbonate resins may be used alone or in a suitable mixture of two or more types. They can also be used in a mixture with the commonly used bisphenol A polycarbonate resin. The manufacturing methods and properties of these special polycarbonate resins are described in detail, for example, in Japanese Patent Application Laid-Open Nos. 6-172508, 8-27370, 2001-55435, and 2002-117580.

Among the various polycarbonate resins mentioned above, those having water absorption and glass transition temperature (Tg) within the following ranges by adjusting the copolymer composition, etc., are particularly suitable in fields where dimensional stability is required, since the polymer itself has good hydrolysis resistance and is remarkably excellent in low warpage after molding.
(i) A polycarbonate resin having a water absorption of 0.05 to 0.15%, preferably 0.06 to 0.13%, and a Tg of 120 to 180°C, or (ii) a polycarbonate resin having a Tg of 160 to 250°C, preferably 170 to 230°C, and a water absorption of 0.10 to 0.30%, preferably 0.13 to 0.30%, more preferably 0.14 to 0.27%.

The water absorption rate of polycarbonate resin is measured using a disk-shaped test piece with a diameter of 45 mm and a thickness of 3.0 mm, after immersing it in water at 23°C for 24 hours in accordance with ISO 62-1980. Furthermore, Tg (glass transition temperature) is a value determined by differential scanning calorimetry (DSC) in accordance with JIS K7121.

Carbonate precursors include carbonyl halides, carbonic acid diesters, and haloformates, and specific examples include phosgene, diphenyl carbonate, and dihaloformates of dihydric phenols.

When producing a polycarbonate resin from the dihydric phenol and carbonate precursor by interfacial polymerization, catalysts, end-capping agents, antioxidants to prevent oxidation of the dihydric phenol, and the like may be used as needed. The polycarbonate resins of the present invention also include branched polycarbonate resins copolymerized with trifunctional or higher polyfunctional aromatic compounds, polyester carbonate resins copolymerized with aromatic or aliphatic (including alicyclic) bifunctional carboxylic acids, copolymer polycarbonate resins copolymerized with bifunctional alcohols (including alicyclic), and polyester carbonate resins copolymerized with such bifunctional carboxylic acids and bifunctional alcohols. Mixtures of two or more of the resulting polycarbonate resins may also be used.

The branched polycarbonate resin can impart anti-drip properties to the resin composition of the present invention. Examples of trifunctional or higher polyfunctional aromatic compounds used in such branched polycarbonate resins include phloroglucin, phloroglucside, 4,6-dimethyl-2,4,6-tris(4-hydroxyphenyl)heptene-2,2,4,6-trimethyl-2,4,6-tris(4-hydroxyphenyl)heptane, 1,3,5-tris(4-hydroxyphenyl)benzene, 1,1,1-tris(4-hydroxyphenyl)ethane, 1,1,1-tris(3,5-dimethyl-4-hydroxyphenyl)ethane, 2,6-bis(2-hydroxy-5-methylbenzyl)-4-methylphenol, 4-{4-[1,1-bis(4- Examples include trisphenols such as {4-hydroxyphenyl)ethyl]benzene}-α,α-dimethylbenzylphenol, tetra(4-hydroxyphenyl)methane, bis(2,4-dihydroxyphenyl)ketone, 1,4-bis(4,4-dihydroxytriphenylmethyl)benzene, trimellitic acid, pyromellitic acid, benzophenonetetracarboxylic acid, and acid chlorides thereof. Of these, 1,1,1-tris(4-hydroxyphenyl)ethane and 1,1,1-tris(3,5-dimethyl-4-hydroxyphenyl)ethane are preferred, with 1,1,1-tris(4-hydroxyphenyl)ethane being particularly preferred.

In the branched polycarbonate resin, the structural units derived from a polyfunctional aromatic compound are preferably 0.01 to 1 mol%, more preferably 0.05 to 0.9 mol%, and even more preferably 0.05 to 0.8 mol%, based on the total 100 mol% of the structural units derived from a dihydric phenol and the structural units derived from such a polyfunctional aromatic compound. In particular, in the case of the melt transesterification method, branched structural units may be generated as a side reaction. The amount of such branched structural units is preferably 0.001 to 1 mol%, more preferably 0.005 to 0.9 mol%, and even more preferably 0.01 to 0.8 mol%, based on the total 100 mol% of the structural units derived from the dihydric phenol. The proportion of such branched structures can be calculated by ^1H -NMR measurement.

The aliphatic difunctional carboxylic acid is preferably an α,ω-dicarboxylic acid. Examples of preferred aliphatic difunctional carboxylic acids include linear saturated aliphatic dicarboxylic acids such as sebacic acid (decanedioic acid), dodecanedioic acid, tetradecanedioic acid, octadecanedioic acid, and icosane dioic acid, as well as alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. Alicyclic diols are more preferred as difunctional alcohols, such as cyclohexanedimethanol, cyclohexanediol, and tricyclodecanedimethanol.

The reaction methods used to produce the polycarbonate resin of the present invention, such as interfacial polymerization, melt transesterification, carbonate prepolymer solid-phase transesterification, and ring-opening polymerization of cyclic carbonate compounds, are well known in various literature and patent publications.

In producing the thermoplastic resin composition of the present invention, the viscosity average molecular weight (M) of the polycarbonate resin is not particularly limited, but is preferably 1.8 x 10 ⁴ to 4.0 x 10 ⁴ , more preferably 2.0 x 10 ⁴ to 3.5 x 10 ⁴ , and even more preferably 2.2 x 10 ⁴ to 3.0 x 10 ^4. Polycarbonate resins with a viscosity average molecular weight of less than 1.8 x 10 ⁴ may not provide good mechanical properties. On the other hand, resin compositions obtained from polycarbonate resins with a viscosity average molecular weight of more than 4.0 x 10 ⁴ are inferior in versatility due to their poor fluidity during injection molding.

The polycarbonate resin may be obtained by blending polycarbonate resins having viscosity average molecular weights outside the above range. In particular, polycarbonate resins having a viscosity average molecular weight exceeding the above range (5 x 10 ⁴ ) have improved entropy elasticity. As a result, they exhibit good moldability in gas-assisted molding and foam molding, which are sometimes used to mold reinforced resin materials into structural components. Such improved moldability is even better than that of the branched polycarbonate resin. In a more preferred embodiment, component A is composed of a polycarbonate resin (component A-1-1) having a viscosity average molecular weight of 7× ^{10 4} to 3×10 ⁵ and an aromatic polycarbonate resin (component A-1-2 ⁾ having a viscosity average molecular weight of 1×10 ⁴ to 3×10 4, and a polycarbonate resin (component A-1) having a viscosity average molecular weight of 1.6×10 4 to 3.5×10 ⁴ (hereinafter, sometimes referred to as a "polycarbonate resin containing a high molecular weight component") can also be used.

In such a high molecular weight component-containing polycarbonate resin (component A-1), the molecular weight of component A-1-1 is preferably 7 x ¹⁰ to 2 x ¹⁰ , more preferably 8 x ¹⁰ to 2 x ¹⁰ , even more preferably 1 x ¹⁰ to 2 x ¹⁰ , and particularly preferably 1 x ¹⁰ to 1.6 x ^10. The molecular weight of component A-1-2 is preferably 1 x ¹⁰ to 2.5 x ¹⁰ , more preferably 1.1 x ¹⁰ to 2.4 x ¹⁰ , even more preferably 1.2 x ¹⁰ to 2.4 x ¹⁰ , and particularly preferably 1.2 x ¹⁰ to 2.3 x ¹⁰ .

The high-molecular-weight polycarbonate resin (component A-1) can be obtained by mixing the aforementioned components A-1-1 and A-1-2 in various ratios and adjusting to satisfy a specified molecular weight range. Preferably, the content of component A-1-1 is 2 to 40% by weight, more preferably 3 to 30% by weight, even more preferably 4 to 20% by weight, and especially preferably 5 to 20% by weight, based on 100% by weight of component A-1.

Methods for preparing component A-1 include: (1) a method in which component A-1-1 and component A-1-2 are polymerized independently and then mixed; (2) a method in which an aromatic polycarbonate resin that exhibits multiple polymer peaks in a molecular weight distribution chart obtained by GPC, such as the method disclosed in JP-A-5-306336, is produced in the same system, and the aromatic polycarbonate resin is produced so as to satisfy the conditions for component A-1 of the present invention; and (3) a method in which an aromatic polycarbonate resin obtained by such a production method (production method (2)) is mixed with separately produced components A-1-1 and/or A-1-2.

The viscosity average molecular weight as used in the present invention is determined by first determining the specific viscosity (η _SP ) calculated by the following formula using an Ostwald viscometer from a solution prepared by dissolving 0.7 g of polycarbonate resin in 100 ml of methylene chloride at 20°C:
Specific viscosity (η _SP )=(t−t ₀ )/t ₀
[ _t0 is the number of seconds for methylene chloride to fall, and t is the number of seconds for the sample solution to fall]
The viscosity average molecular weight M is calculated from the determined specific viscosity (η _SP ) using the following formula.
η _SP /c = [η] + 0.45 × [η] ² c (where [η] is the intrinsic viscosity)
[η]=1.23× ^10-4 M ^0.83
c=0.7

The viscosity average molecular weight of the polycarbonate resin in the thermoplastic resin composition of the present invention is calculated as follows: The composition is mixed with 20 to 30 times its weight of methylene chloride to dissolve the soluble components in the composition. The soluble components are collected by filtration through Celite. The solvent in the resulting solution is then removed. The solid obtained after solvent removal is thoroughly dried to obtain a solid of components soluble in methylene chloride. 0.7 g of this solid is dissolved in 100 ml of methylene chloride, and the specific viscosity at 20°C is determined in the same manner as above. The viscosity average molecular weight M is then calculated from this specific viscosity in the same manner as above.

A polycarbonate-polydiorganosiloxane copolymer resin can also be used as the polycarbonate resin of the present invention. The polycarbonate-polydiorganosiloxane copolymer resin is preferably a copolymer resin containing dihydric phenol units represented by the following general formula (1) and hydroxyaryl-terminated polydiorganosiloxane units represented by the following general formula (3):

[In the above general formula (1), ^R1 and ^R2 each independently represent a group selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, a cycloalkyl group having 6 to 20 carbon atoms, a cycloalkoxy group having 6 to 20 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an aryl group having 6 to 14 carbon atoms, an aryloxy group having 6 to 14 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, an aralkyloxy group having 7 to 20 carbon atoms, a nitro group, an aldehyde group, a cyano group, and a carboxy group; when there are multiple of each, they may be the same or different; a and b each represent an integer of 1 to 4; and W is a single bond or at least one group selected from the group consisting of groups represented by the following general formula (2)]

(In the above general formula (2), R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ and R ¹⁸ each independently represent a group selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an aryl group having 6 to 14 carbon atoms and an aralkyl group having 7 to 20 carbon atoms; R ¹⁹ and R ²⁰ each independently represent a group selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a cycloalkyl group having 6 to 20 carbon atoms, a cycloalkoxy group having 6 to 20 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an aryl group having 6 to 14 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, an aralkyloxy group having 7 to 20 carbon atoms, a nitro group, an aldehyde group, a cyano group, and a carboxy group; when there are a plurality of 20, they may be the same or different; c is an integer from 1 to 10, and d is an integer from 4 to 7.

[In the above general formula (3), R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ each independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms; R ⁹ and R ¹⁰ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms; e and f each represent an integer of 1 to 4; p is a natural number; q is 0 or a natural number; and p+q is a natural number of 4 or greater and 150 or less; and X is a divalent aliphatic group having 2 to 8 carbon atoms.]

Examples of dihydric phenols (I) that derive the carbonate structural unit represented by general formula (1) include 4,4'-dihydroxybiphenyl, bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 2,2-bis(4-hydroxy-3,3'-biphenyl)propane, 2,2-bis(4-hydroxy-3-isopropylphenyl)propane, 2,2-bis(3-t-butyl-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane, 2,2-bis(3-bromo-4-hydroxyphenyl)propane, 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, 2,2-bis(3-cyclohexyl-4-hydroxyphenyl)propane, 1,1-bis(3-cyclohexyl-4-hydroxyphenyl)cyclohexane, bis(4-hydroxyphenyl)diphenylmethane, 9,9-bis(4-hydroxyphenyl)fluorene, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene , 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)cyclopentane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether, 4,4'-sulfonyldiphenol, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxydiphenyl sulfide, 2,2'-dimethyl-4,4'-sulfonyldiphenol, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide, 2,2'-diphenyl-4,4'-sulfonyldiphenol, 4, Examples include 4'-dihydroxy-3,3'-diphenyldiphenyl sulfoxide, 4,4'-dihydroxy-3,3'-diphenyldiphenyl sulfide, 1,3-bis{2-(4-hydroxyphenyl)propyl}benzene, 1,4-bis{2-(4-hydroxyphenyl)propyl}benzene, 1,4-bis(4-hydroxyphenyl)cyclohexane, 1,3-bis(4-hydroxyphenyl)cyclohexane, 4,8-bis(4-hydroxyphenyl)tricyclo[5.2.1.02,6]decane, 4,4'-(1,3-adamantanediyl)diphenol, and 1,3-bis(4-hydroxyphenyl)-5,7-dimethyladamantane.

Among these, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, 4,4'-sulfonyldiphenol, 2,2'-dimethyl-4,4'-sulfonyldiphenol, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 1,3-bis{2-(4-hydroxyphenyl)propyl}benzene, and 1,4-bis{2-(4-hydroxyphenyl)propyl}benzene are preferred, and 2,2-bis(4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane (BPZ), 4,4'-sulfonyldiphenol, and 9,9-bis(4-hydroxy-3-methylphenyl)fluorene are particularly preferred. Of these, 2,2-bis(4-hydroxyphenyl)propane is the most suitable, as it has excellent strength and good durability. These may be used alone or in combination.

In the carbonate structural unit represented by the general formula (3) above, ^R3 , ^R4 , ^R5 , ^R6 , ^R7 , and ^R8 are each independently preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, with a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group being particularly preferred. ^R9 and ^R10 are each independently preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, with a hydrogen atom or an alkyl group having 1 to 4 carbon atoms being particularly preferred. As the dihydroxyaryl-terminated polydiorganosiloxane (II) from which the carbonate structural unit represented by the general formula (3) is derived, for example, a compound such as that shown in the following general formula (I) is suitably used.

p+q is preferably 4 to 120, more preferably 30 to 120, even more preferably 30 to 100, and most preferably 30 to 60.

Next, a method for producing the above-mentioned preferred polycarbonate-polydiorganosiloxane copolymer resin will be described below. A mixed solution of chloroformate compounds containing chloroformate of dihydric phenol (I) and/or carbonate oligomer of dihydric phenol (I) having terminal chloroformate groups is prepared by reacting dihydric phenol (I) with a chloroformate-forming compound such as phosgene or the chloroformate of dihydric phenol (I) in a mixed solution of a water-insoluble organic solvent and an alkaline aqueous solution. Phosgene is preferred as the chloroformate-forming compound.

When producing a chloroformate compound from dihydric phenol (I), the entire amount of dihydric phenol (I) from which the carbonate structural unit represented by general formula (1) is derived may be converted into the chloroformate compound at once, or a portion of it may be added as a post-added monomer as a reaction raw material to the subsequent interfacial polycondensation reaction. The post-added monomer is added to facilitate the subsequent polycondensation reaction and need not be added if not necessary. While the method for this chloroformate compound production reaction is not particularly limited, it is typically carried out in a solvent in the presence of an acid binder. Furthermore, if desired, a small amount of an antioxidant such as sodium sulfite or hydrosulfide may be added, and this addition is preferred. The proportion of the chloroformate-forming compound used may be adjusted appropriately, taking into account the stoichiometric ratio (equivalents) of the reaction. Furthermore, when using phosgene, a preferred chloroformate-forming compound, a method of blowing gasified phosgene into the reaction system is preferably used.

Examples of the acid binder include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkali metal carbonates such as sodium carbonate and potassium carbonate, organic bases such as pyridine, and mixtures of these. Similarly, the proportion of the acid binder used can be determined appropriately taking into account the stoichiometric ratio (equivalents) of the reaction. Specifically, it is preferable to use 2 equivalents or a slight excess of the acid binder per mole of dihydric phenol (I) used to form the chloroformate compound of dihydric phenol (I) (usually 1 mole corresponds to 2 equivalents).

The solvent may be any of a variety of inert solvents, such as those used in the production of known polycarbonates, and may be used alone or in combination. Typical examples include hydrocarbon solvents such as xylene, and halogenated hydrocarbon solvents such as methylene chloride and chlorobenzene. Halogenated hydrocarbon solvents such as methylene chloride are particularly preferred.

There are no particular restrictions on the pressure in the reaction to produce chloroformate compounds; normal, elevated, or reduced pressure may be used, but it is usually advantageous to carry out the reaction at normal pressure. The reaction temperature is selected from the range of -20 to 50°C, and since the reaction often generates heat, water or ice cooling is desirable. The reaction time depends on other conditions and cannot be specified in general, but is usually carried out for 0.2 to 10 hours. The pH range for the reaction to produce chloroformate compounds can be determined using known interfacial reaction conditions, and the pH is usually adjusted to 10 or higher.

In producing the polycarbonate-polydiorganosiloxane copolymer resin of the present invention, after preparing a mixed solution of chloroformate compounds containing the chloroformate of dihydric phenol (I) and a carbonate oligomer of dihydric phenol (I) having terminal chloroformate groups in the manner described above, dihydroxyaryl-terminated polydiorganosiloxane (II) from which carbonate structural units represented by general formula (3) are derived is added to the mixed solution while stirring at a rate of 0.01 mol/min or less per mole of dihydric phenol (I) charged in preparing the mixed solution, and the dihydroxyaryl-terminated polydiorganosiloxane (II) and the chloroformate compound are subjected to interfacial polycondensation to produce a polycarbonate-polydiorganosiloxane copolymer resin.

Polycarbonate-polydiorganosiloxane copolymer resins can be made into branched polycarbonate-polydiorganosiloxane copolymer resins by using a branching agent in combination with a dihydric phenol compound. Examples of trifunctional or higher polyfunctional aromatic compounds used in such branched polycarbonate resins include phloroglucin, phloroglucside, 4,6-dimethyl-2,4,6-tris(4-hydroxyphenyl)heptene-2,2,4,6-trimethyl-2,4,6-tris(4-hydroxyphenyl)heptane, 1,3,5-tris(4-hydroxyphenyl)benzene, 1,1,1-tris(4-hydroxyphenyl)ethane, 1,1,1-tris(3,5-dimethyl-4-hydroxyphenyl)ethane, 2,6-bis(2-hydroxy-5-methylbenzyl)-4-methylphenol, 4-[4-[1,1-bis(4- Examples include trisphenols such as {4-hydroxyphenyl)ethyl]benzene}-α,α-dimethylbenzylphenol, tetra(4-hydroxyphenyl)methane, bis(2,4-dihydroxyphenyl)ketone, 1,4-bis(4,4-dihydroxytriphenylmethyl)benzene, trimellitic acid, pyromellitic acid, benzophenonetetracarboxylic acid, and acid chlorides thereof. Of these, 1,1,1-tris(4-hydroxyphenyl)ethane and 1,1,1-tris(3,5-dimethyl-4-hydroxyphenyl)ethane are preferred, with 1,1,1-tris(4-hydroxyphenyl)ethane being particularly preferred.

The method for producing such a branched polycarbonate-polydiorganosiloxane copolymer resin may be a method in which a branching agent is included in the mixed solution during the chloroformate compound production reaction, or a method in which a branching agent is added during the interfacial polycondensation reaction after the production reaction. The proportion of carbonate structural units derived from the branching agent is preferably 0.005 to 1.5 mol%, more preferably 0.01 to 1.2 mol%, and particularly preferably 0.05 to 1.0 mol%, of the total amount of carbonate structural units constituting the copolymer resin. The amount of branched structures can be calculated by ^1H -NMR measurement.

The pressure in the system during the polycondensation reaction can be reduced, normal, or increased, but is typically carried out at normal pressure or the reaction system's own pressure. The reaction temperature is selected from the range of −20 to 50°C. In many cases, heat is generated during polymerization, so water or ice cooling is desirable. The reaction time cannot be generally specified because it varies depending on other conditions such as the reaction temperature, but it is typically carried out for 0.5 to 10 hours. In some cases, the resulting polycarbonate-polydiorganosiloxane copolymer resin can be subjected to appropriate physical treatments (mixing, fractionation, etc.) and/or chemical treatments (polymer reaction, crosslinking treatment, partial decomposition treatment, etc.) to obtain a polycarbonate-polydiorganosiloxane copolymer resin with the desired reduced viscosity [η _SP /c]. The resulting reaction product (crude product) can be subjected to various post-treatments, such as known separation and purification methods, to recover a polycarbonate-polydiorganosiloxane copolymer resin with the desired purity (degree of purification).

The content of the polydiorganosiloxane block represented by the following general formula (4) contained in the above general formula (3) is preferably 1.0 to 10.0% by weight, more preferably 1.0 to 8.0% by weight, even more preferably 1.0 to 5.0% by weight, and most preferably 1.0 to 3.0% by weight, based on the total weight of the polycarbonate resin composition.

(In the above general formula (4), R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ each independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms; p is a natural number; q is 0 or a natural number; and p+q is a natural number of 4 or more and 150 or less.)

<Component B: Expansion-treated graphite>
The resin composition of the present invention contains thermally expanded graphite as component B. The thermally expanded graphite used in the present invention is artificial graphite obtained by heat-treating natural graphite, petroleum coke, petroleum pitch, amorphous carbon, or the like, which is naturally occurring as a mineral, at 2000°C or higher to artificially orient irregularly arranged micrographite crystals. The artificial graphite is then immersed in concentrated sulfuric acid, concentrated nitric acid, or the like, and further treated with an oxidizing agent such as hydrogen peroxide or hydrochloric acid to form a graphite intercalation compound. The compound is then washed with water and rapidly heated to 800 to 1000°C to expand the graphite in the C-axis direction of the raw graphite. When graphite that has not been thermally expanded is used, it disperses poorly in the resin, resulting in a significant decrease in the bond strength between the resin and metal after a heat cycle test. Natural graphite is particularly preferred as the graphite to be thermally expanded.

It is desirable that this thermally expanded graphite be prepared by subjecting the graphite to the thermal expansion treatment described above and then pulverizing it. Furthermore, the expanded graphite that has been thermally expanded is in a cocoon-like expanded form, and generally has a specific volume of 100 cc/g or more. While it is possible to pulverize the expanded graphite in this form using various known pulverizers, it is more preferable to compress the cocoon-like expanded graphite using a roll, press, etc., to form it into a sheet, and then pulverize this sheet using various known pulverizers.

This thermally expanded graphite is classified as needed before use, and is further washed with water and dried as needed to reduce residual acid components. Its average particle size is preferably 0.1 to 1000 μm, more preferably 25 to 1000 μm. If the average particle size is less than 0.1 μm, extrusion stability during resin composition production may be poor, resulting in reduced productivity. If the average particle size exceeds 1000 μm, the appearance of the molded product surface may be poor.

The surface of the thermally expanded graphite of the present invention may be subjected to a surface treatment, such as an epoxy treatment, urethane treatment, silane coupling treatment, or oxidation treatment, in order to increase affinity with aromatic polycarbonate resins, as long as the properties of the composition of the present invention are not impaired. Furthermore, the apparent bulk density of the thermally expanded graphite of the present invention is preferably 0.01 to 0.50 g/cc, more preferably 0.05 to 0.30 g/cc, and even more preferably 0.10 to 0.25 g/cc. If the apparent bulk density exceeds 0.50 g/cc, the expansion ratio of the expanded graphite will be low, and thermal conductivity may be poor. If the apparent bulk density is less than 0.01 g/cc, extrusion stability during resin composition production may be poor, resulting in reduced productivity.

The content of Component B is 1 to 80 parts by weight, preferably 5 to 60 parts by weight, and more preferably 10 to 40 parts by weight, per 100 parts by weight of Component A. If the content of Component B is less than 1 part by weight, the retention rate of the bond strength between the resin and metal after a heat cycle test will be significantly reduced. Furthermore, if the content exceeds 80 parts by weight, the fluidity of the resin will decrease, resulting in insufficient penetration of the resin into the grooves on the metal surface during metal insert molding, and insufficient bond strength between the resin and metal will be obtained.

<Component C: Fibrous Filler>
The resin composition of the present invention preferably contains a fibrous filler as component C. Examples of fibrous fillers include glass fibers, carbon fibers, milled carbon fibers, metal fibers, asbestos, rock wool, ceramic fibers, slag fibers, potassium titanate whiskers, boron whiskers, aluminum borate whiskers, calcium carbonate whiskers, titanium oxide whiskers, wollastonite, xonotlite, palygorskite (attapulgite), and sepiolite, as well as fibrous heat-resistant organic fillers such as aramid fibers, polyimide fibers, and polybenzthiazole fibers, as well as fibrous fillers obtained by surface-coating these fillers with a different material, such as a metal or metal oxide. Examples of fillers surface-coated with a different material include metal-coated glass fibers and metal-coated carbon fibers. The method for coating the surface of a dissimilar material is not particularly limited, and examples include various known plating methods (e.g., electrolytic plating, electroless plating, hot-dip plating, etc.), vacuum deposition, ion plating, CVD methods (e.g., thermal CVD, MOCVD, plasma CVD, etc.), PVD, and sputtering. Among these fibrous fillers, glass fiber, carbon fiber, milled carbon fiber, and aramid fiber are preferred, with glass fiber and carbon fiber being more preferred. The fiber diameter of the fibrous filler is preferably in the range of 0.1 to 20 μm. The upper limit of the fiber diameter is more preferably 18 μm, and even more preferably 15 μm. Meanwhile, the lower limit of the fiber diameter is more preferably 1 μm, and even more preferably 6 μm. The fiber diameter here refers to the number-average fiber diameter. The number-average fiber diameter is a value calculated from images obtained by scanning electron microscopy of the residue collected after dissolving a molded product in a solvent or decomposing a resin with a basic compound, and the ashing residue collected after ashing in a crucible.

When the fibrous filler is glass fiber, the glass composition of the glass fiber is not particularly limited, and may be any of various glass compositions, such as A-glass, C-glass, and E-glass. Such glass fillers may optionally contain components such as TiO ₂ , SO ₃ , and P ₂ O ₅ . Among these, E-glass (alkali-free glass) is more preferred. Glass fibers that have been surface-treated with a known surface treatment agent, such as a silane coupling agent, titanate coupling agent, or aluminate coupling agent, are preferred in terms of improved mechanical strength. Furthermore, glass fibers that have been bundled with olefin-based resins, styrene-based resins, acrylic-based resins, polyester-based resins, epoxy-based resins, and urethane-based resins are preferred, with epoxy-based resins and urethane-based resins being particularly preferred in terms of mechanical strength. The amount of sizing agent attached to the bundled glass fibers is preferably 0.1 to 3 wt %, more preferably 0.2 to 1 wt %, based on 100 wt % of the glass fibers. Flat-section glass fibers can also be used as the fibrous filler. The flat cross-section glass fiber is a glass fiber having an average major axis of the fiber cross-section of preferably 10 to 50 μm, more preferably 15 to 40 μm, and even more preferably 20 to 35 μm, and an average major axis to minor axis ratio (major axis/minor axis) of preferably 1.5 to 8, more preferably 2 to 6, and even more preferably 2.5 to 5. When a flat cross-section glass fiber having an average major axis to minor axis ratio within this range is used, the anisotropy is greatly improved compared to when a non-circular cross-section fiber having a cross-section of less than 1.5 is used. Furthermore, examples of the flat cross-sectional shape include, in addition to flat, non-circular cross-sectional shapes such as elliptical, cocoon-shaped, and trilobal shapes, or shapes similar thereto. Among these, a flat shape is preferred from the viewpoints of improving mechanical strength and low anisotropy. The ratio of the average fiber length to the average fiber diameter (aspect ratio) of the flat cross-section glass fiber is preferably 2 to 120, more preferably 2.5 to 70, and even more preferably 3 to 50. A fiber length to average fiber diameter ratio of less than 2 may result in a reduced effect on improving mechanical strength, while a fiber length to average fiber diameter ratio of more than 120 may result in increased anisotropy and a deterioration in the appearance of the molded article. The average fiber diameter of the flat cross-section glass fiber refers to the number-average fiber diameter when the flat cross-section shape is converted into a perfect circle of the same area. The average fiber length refers to the number-average fiber length in the reinforced polycarbonate resin composition of the present invention. The number-average fiber length is a value calculated using an image analyzer from an optical microscope image of the filler residue collected after processing such as high-temperature incineration of a molded article, dissolution with a solvent, or chemical decomposition. The value is calculated using the fiber diameter as a guide, excluding fibers with lengths less than that.

The content of Component C is preferably 1 to 100 parts by weight, more preferably 5 to 80 parts by weight, and even more preferably 10 to 50 parts by weight, per 100 parts by weight of Component A. If the content of Component C is less than 1 part by weight, peeling may occur during insert molding, and if it exceeds 100 parts by weight, sufficient bonding strength between the resin and metal may not be achieved.

(Other additives)
In order to improve the thermal stability and designability of the thermoplastic resin composition of the present invention, additives used for these purposes can be advantageously used. These additives will be specifically described below.

(I) Heat Stabilizer The thermoplastic resin composition of the present invention may contain various known stabilizers, such as phosphorus-based stabilizers and hindered phenol-based antioxidants.

(i) Phosphorus-Based Stabilizer The thermoplastic resin composition of the present invention preferably contains a phosphorus-based stabilizer to the extent that it does not promote hydrolysis. Such a phosphorus-based stabilizer improves thermal stability during production or molding processing, and improves mechanical properties, color, and molding stability. Examples of phosphorus-based stabilizers include phosphorous acid, phosphoric acid, phosphonous acid, phosphonic acid, and esters thereof, as well as tertiary phosphines. Specific examples of the phosphite compound include triphenyl phosphite, tris(nonylphenyl)phosphite, tridecyl phosphite, trioctyl phosphite, trioctadecyl phosphite, didecyl monophenyl phosphite, dioctyl monophenyl phosphite, diisopropyl monophenyl phosphite, monobutyl diphenyl phosphite, monodecyl diphenyl phosphite, monooctyl diphenyl phosphite, 2,2-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite, tris(diethylphenyl)phosphite, tris(di-iso-propylphenyl)phosphite, and tris(di-n-butylphenyl)phosphite. bis(2,6-di-tert-butylphenyl) phosphite, tris(2,4-di-tert-butylphenyl) phosphite, distearyl pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-ethylphenyl) pentaerythritol diphosphite, phenyl bisphenol A pentaerythritol diphosphite, bis(nonylphenyl) pentaerythritol diphosphite, dicyclohexyl pentaerythritol diphosphite, etc. Furthermore, as other phosphite compounds, those which react with dihydric phenols to have a cyclic structure can also be used. For example, 2,2'-methylenebis(4,6-di-tert-butylphenyl)(2,4-di-tert-butylphenyl)phosphite, 2,2'-methylenebis(4,6-di-tert-butylphenyl)(2-tert-butyl-4-methylphenyl)phosphite, 2,2'-methylenebis(4-methyl-6-tert-butylphenyl)(2-tert-butyl-4-methylphenyl)phosphite, 2,2'-ethylidenebis(4-methyl-6-tert-butylphenyl)(2-tert-butyl-4-methylphenyl)phosphite, and the like can be mentioned. Examples of the phosphate compound include tributyl phosphate, trimethyl phosphate, tricresyl phosphate, triphenyl phosphate, trichlorophenyl phosphate, triethyl phosphate, diphenyl cresyl phosphate, diphenyl monoorthoxenyl phosphate, tributoxyethyl phosphate, dibutyl phosphate, dioctyl phosphate, and diisopropyl phosphate, and preferred are triphenyl phosphate and trimethyl phosphate.

Phosphonite compounds include tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite, tetrakis(2,4-di-tert-butylphenyl)-4,3'-biphenylene diphosphonite, tetrakis(2,4-di-tert-butylphenyl)-3,3'-biphenylene diphosphonite, tetrakis(2,6-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite, tetrakis(2,6-di-tert-butylphenyl)-4,3'-biphenylene diphosphonite, tetrakis(2,6-di-tert-butylphenyl)-3,3'-biphenylene diphosphonite, bis(2,4-di-tert-butylphenyl)-4-phenyl-phenylphosphonite, bis Examples of suitable phosphonite compounds include (2,4-di-tert-butylphenyl)-3-phenyl-phenyl phosphonite, bis(2,6-di-n-butylphenyl)-3-phenyl-phenyl phosphonite, bis(2,6-di-tert-butylphenyl)-4-phenyl-phenyl phosphonite, and bis(2,6-di-tert-butylphenyl)-3-phenyl-phenyl phosphonite. Preferred are tetrakis(di-tert-butylphenyl)-biphenylene diphosphonite and bis(di-tert-butylphenyl)-phenyl-phenyl phosphonite. Tetrakis(2,4-di-tert-butylphenyl)-biphenylene diphosphonite and bis(2,4-di-tert-butylphenyl)-phenyl-phenyl phosphonite are more preferred. Such phosphonite compounds can be used in combination with the above-mentioned phosphite compounds having an aryl group substituted with two or more alkyl groups, which is preferred. Examples of suitable phosphonate compounds include dimethyl benzenephosphonate, diethyl benzenephosphonate, and dipropyl benzenephosphonate. Examples of tertiary phosphines include triethylphosphine, tripropylphosphine, tributylphosphine, trioctylphosphine, triamylphosphine, dimethylphenylphosphine, dibutylphenylphosphine, diphenylmethylphosphine, diphenyloctylphosphine, triphenylphosphine, tri-p-tolylphosphine, trinaphthylphosphine, and diphenylbenzylphosphine. A particularly preferred tertiary phosphine is triphenylphosphine. The above phosphorus-based stabilizers can be used alone or in combination with two or more. Among the above phosphorus-based stabilizers, alkyl phosphate compounds, such as trimethyl phosphate, are preferred. Using such alkyl phosphate compounds in combination with phosphite compounds and/or phosphonite compounds is also a preferred embodiment.

(ii) Hindered Phenol Antioxidant A hindered phenol-based antioxidant can be blended into the thermoplastic resin composition of the present invention. Such blending is effective in suppressing deterioration of color during molding processing and over long-term use. Examples of hindered phenol-based antioxidants include α-tocopherol, butylhydroxytoluene, sinapyl alcohol, vitamin E, n-octadecyl-β-(4'-hydroxy-3',5'-di-tert-butylphenyl)propionate, 2-tert-butyl-6-(3'-tert-butyl-5'-methyl-2'-hydroxybenzyl)-4-methylphenyl acrylate, 2,6-di-tert-butyl-4-(N,N -dimethylaminomethyl)phenol, 3,5-di-tert-butyl-4-hydroxybenzylphosphonate diethyl ester, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 4,4'-methylenebis(2,6-di-tert-butylphenol), 2,2'-methylenebis(4-methyl-6-cyclohexylphenol), 2 , 2'-dimethylene-bis(6-α-methyl-benzyl-p-cresol) 2,2'-ethylidene-bis(4,6-di-tert-butylphenol), 2,2'-butylidene-bis(4-methyl-6-tert-butylphenol), 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), triethylene glycol-N-bis-3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate terephthalate, 1,6-hexanediol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], bis[2-tert-butyl-4-methyl 6-(3-tert-butyl-5-methyl-2-hydroxybenzyl)phenyl]terephthalate, 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1,-dimethylethyl}-2,4,8,10-terephthalate Traoxaspiro[5,5]undecane, 4,4'-thiobis(6-tert-butyl-m-cresol), 4,4'-thiobis(3-methyl-6-tert-butylphenol), 2,2'-thiobis(4-methyl-6-tert-butylphenol), bis(3,5-di-tert-butyl-4-hydroxybenzyl)sulfide, 4,4'-di-thiobis(2,6-di-tert-butylphenol), 4,4'-tri-thiobis( 2,6-di-tert-butylphenol), 2,2-thiodiethylenebis-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,4-bis(n-octylthio)-6-(4-hydroxy-3',5'-di-tert-butylanilino)-1,3,5-triazine, N,N'-hexamethylenebis-(3,5-di-tert-butyl-4-hydroxyhydrocinnamide), N,N'-bis[3-(3 ,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, tris(3,5-di-tert-butyl-4-hydroxyphenyl)isocyanurate, tris(3,5-di-tert-butyl-4- Examples of suitable hindered phenol antioxidants include 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate, 1,3,5-tris-2[3(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]ethyl isocyanurate, and tetrakis[methylene-3-(3',5'-di-tert-butyl-4-hydroxyphenyl)propionate]methane. All of these are readily available. The above hindered phenol antioxidants can be used alone or in combination of two or more. The amounts of the phosphorus-based stabilizer and the hindered phenol-based antioxidant are each preferably 0.0001 to 1 part by weight, more preferably 0.001 to 0.5 parts by weight, and even more preferably 0.005 to 0.3 parts by weight per 100 parts by weight of Component A.

(iii) Heat Stabilizers Other Than the Above-mentioned: The thermoplastic resin composition of the present invention can also contain heat stabilizers other than the phosphorus-based stabilizer and hindered phenol-based antioxidant. Suitable examples of such heat stabilizers include lactone-based stabilizers, such as the reaction product of 3-hydroxy-5,7-di-tert-butyl-furan-2-one and o-xylene. Details of such stabilizers are described in Japanese Patent Laid-Open Publication No. 7-233160. This compound is commercially available as Irganox HP-136 (trademark, manufactured by CIBA SPECIALTY CHEMICALS), and this compound can be used. Furthermore, stabilizers containing this compound in combination with various phosphite compounds and hindered phenol compounds are commercially available. A suitable example is Irganox HP-2921 manufactured by the same company. The amount of lactone-based stabilizer blended is preferably 0.0005 to 0.05 parts by weight, more preferably 0.001 to 0.03 parts by weight, per 100 parts by weight of Component A. Other stabilizers include sulfur-containing stabilizers such as pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(3-laurylthiopropionate), and glycerol-3-stearylthiopropionate. The amount of such sulfur-containing stabilizer blended is preferably 0.001 to 0.1 parts by weight, more preferably 0.01 to 0.08 parts by weight, per 100 parts by weight of Component A. An epoxy compound can be blended into the thermoplastic resin composition of the present invention as needed. Such epoxy compounds are blended for the purpose of inhibiting mold corrosion, and essentially any compound having an epoxy functional group can be used. Specific examples of preferred epoxy compounds include 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexylcarboxylate, 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol, a copolymer of methyl methacrylate and glycidyl methacrylate, a copolymer of styrene and glycidyl methacrylate, etc. The amount of such epoxy compound added is preferably 0.003 to 0.2 parts by weight, more preferably 0.004 to 0.15 parts by weight, and even more preferably 0.005 to 0.1 parts by weight, per 100 parts by weight of Component A.

(II) Flame Retardant The thermoplastic resin composition of the present invention can be blended with a flame retardant. The incorporation of such compounds not only improves flame retardancy, but also, depending on the properties of each compound, improves antistatic properties, fluidity, rigidity, and thermal stability, among other things. Examples of such flame retardants include (i) organometallic salt-based flame retardants (e.g., organic alkali (earth) metal sulfonates, organic borate metal salt-based flame retardants, and organic stannate metal salt-based flame retardants), (ii) organophosphorus-based flame retardants (e.g., organic group-containing monophosphate compounds, phosphate oligomer compounds, phosphonate oligomer compounds, phosphonitrile oligomer compounds, and phosphonic acid amide compounds), (iii) silicone-based flame retardants consisting of silicone compounds, and (iv) fibrillated PTFE. Of these, organometallic salt-based flame retardants and organophosphorus-based flame retardants are preferred. These may be used alone or in combination.

(i) Organic Metal Salt-Based Flame Retardants The organic metal salt compound is preferably an alkali (earth) metal salt of an organic acid having 1 to 50 carbon atoms, preferably 1 to 40 carbon atoms, and preferably an alkali (earth) metal salt of an organic sulfonate. Examples of the alkali (earth) metal salt of an organic sulfonate include metal salts of fluorine-substituted alkylsulfonic acids, such as metal salts of perfluoroalkylsulfonic acids having 1 to 10 carbon atoms, preferably 2 to 8 carbon atoms, with alkali metals or alkaline earth metals, and metal salts of aromatic sulfonic acids having 7 to 50 carbon atoms, preferably 7 to 40 carbon atoms, with alkali metals or alkaline earth metals. Examples of alkali metals constituting the metal salt include lithium, sodium, potassium, rubidium, and cesium, while examples of alkaline earth metals include beryllium, magnesium, calcium, strontium, and barium. Alkali metals are more preferred. Among these alkali metals, rubidium and cesium, which have a larger ionic radius, are preferred when higher transparency is required. However, these metals are not widely used and are difficult to purify, which can result in cost disadvantages. On the other hand, metals with smaller ionic radii, such as lithium and sodium, may be disadvantageous in terms of flame retardancy. Taking these factors into consideration, the alkali metals in the alkali metal sulfonates can be selected appropriately, but potassium sulfonates, which have an excellent balance of properties in all respects, are most suitable. Such potassium salts can also be used in combination with alkali metal sulfonates of other alkali metals.

Specific examples of alkali metal salts of perfluoroalkylsulfonates include potassium trifluoromethanesulfonate, potassium perfluorobutanesulfonate, potassium perfluorohexanesulfonate, potassium perfluorooctane sulfonate, sodium pentafluoroethanesulfonate, sodium perfluorobutanesulfonate, sodium perfluorooctane sulfonate, lithium trifluoromethanesulfonate, lithium perfluorobutanesulfonate, lithium perfluoroheptanesulfonate, cesium trifluoromethanesulfonate, cesium perfluorobutanesulfonate, cesium perfluorooctane sulfonate, cesium perfluorohexanesulfonate, rubidium perfluorobutanesulfonate, and rubidium perfluorohexanesulfonate. These can be used alone or in combination of two or more. The number of carbon atoms in the perfluoroalkyl group is preferably 1 to 18, more preferably 1 to 10, and even more preferably 1 to 8.

Among these, potassium perfluorobutanesulfonate is particularly preferred. Perfluoroalkylsulfonic acid alkali (earth) metal salts made from alkali metals usually contain a significant amount of fluoride ions (F-). The presence of such fluoride ions can reduce flame retardancy, so it is preferable to reduce their content as much as possible. The proportion of such fluoride ions can be measured by ion chromatography. The fluoride ion content is preferably 100 ppm or less, more preferably 40 ppm or less, and particularly preferably 10 ppm or less. For production efficiency, a content of 0.2 ppm or more is also preferred. Such alkali (earth) metal perfluoroalkylsulfonate salts with reduced fluoride ion content can be produced using known production methods, including reducing the amount of fluoride ions contained in the raw materials used to produce the fluorine-containing organometallic salt; removing hydrogen fluoride and other products obtained by the reaction by heating or using gas generated during the reaction; and reducing the amount of fluoride ions by purifying the fluorine-containing organometallic salt using recrystallization, reprecipitation, or other purification methods. Because organometallic salt flame retardants are relatively soluble in water, they are preferably produced using ion-exchanged water, particularly water with an electrical resistance of 18 MΩ cm or greater, i.e., an electrical conductivity of approximately 0.55 μS/cm or less, by dissolving and washing the salt at a temperature higher than room temperature, followed by cooling and recrystallization.

Specific examples of alkali (earth) metal salts of aromatic sulfonates include disodium diphenyl sulfide-4,4'-disulfonate, dipotassium diphenyl sulfide-4,4'-disulfonate, potassium 5-sulfoisophthalate, sodium 5-sulfoisophthalate, polysodium polyethylene terephthalate polysulfonate, calcium 1-methoxynaphthalene-4-sulfonate, disodium 4-dodecylphenyl ether disulfonate, polysodium poly(2,6-dimethylphenylene oxide) polysulfonate, polysodium poly(1,3-phenylene oxide) polysulfonate, polysodium poly(1,4-phenylene oxide) polysulfonate, polypotassium poly(2,6-diphenylphenylene oxide) polysulfonate, lithium poly(2-fluoro-6-butylphenylene oxide) polysulfonate, potassium sulfonate of benzenesulfonate, sodium benzenesulfonate, and benzenesulfonic acid Examples of suitable sulfonates include strontium, magnesium benzenesulfonate, dipotassium p-benzenedisulfonate, dipotassium naphthalene-2,6-disulfonate, calcium biphenyl-3,3'-disulfonate, sodium diphenylsulfone-3-sulfonate, potassium diphenylsulfone-3-sulfonate, dipotassium diphenylsulfone-3,3'-disulfonate, dipotassium diphenylsulfone-3,4'-disulfonate, sodium α,α,α-trifluoroacetophenone-4-sulfonate, dipotassium benzophenone-3,3'-disulfonate, disodium thiophene-2,5-disulfonate, dipotassium thiophene-2,5-disulfonate, calcium thiophene-2,5-disulfonate, sodium benzothiophenesulfonate, potassium diphenylsulfoxide-4-sulfonate, a formalin condensate of sodium naphthalenesulfonate, and a formalin condensate of sodium anthracenesulfonate. Of these alkali (earth) metal salts of aromatic sulfonates, potassium salts are particularly preferred. Of these alkali (earth) metal salts of aromatic sulfonates, potassium diphenylsulfone-3-sulfonate and dipotassium diphenylsulfone-3,3'-disulfonate are preferred, and mixtures of these (with a weight ratio of the former to the latter of 15/85 to 30/70) are particularly preferred.

Suitable examples of organic metal salts other than alkali (earth) metal sulfonates include alkali (earth) metal salts of sulfates and alkali (earth) metal salts of aromatic sulfonamides. Examples of alkali (earth) metal salts of sulfates include alkali (earth) metal salts of sulfates of monohydric and/or polyhydric alcohols. Examples of sulfates of monohydric and/or polyhydric alcohols include methyl sulfate, ethyl sulfate, lauryl sulfate, hexadecyl sulfate, sulfates of polyoxyethylene alkylphenyl ethers, mono-, di-, tri-, and tetra-sulfates of pentaerythritol, sulfates of lauric acid monoglyceride, sulfates of palmitic acid monoglyceride, and sulfates of stearic acid monoglyceride. Examples of alkali (earth) metal salts of these sulfates include alkali (earth) metal salts of lauryl sulfate. Examples of alkali (earth) metal salts of aromatic sulfonamides include saccharin, N-(p-tolylsulfonyl)-p-toluenesulfonimide, N-(N'-benzylaminocarbonyl)sulfanilimide, and alkali (earth) metal salts of N-(phenylcarboxyl)sulfanilimide. The content of the organometallic salt flame retardant is preferably 0.001 to 1 part by weight, more preferably 0.005 to 0.5 parts by weight, even more preferably 0.01 to 0.3 parts by weight, and particularly preferably 0.03 to 0.15 parts by weight, per 100 parts by weight of Component A.

(ii) Organic phosphorus flame retardant As the organic phosphorus flame retardant, an aryl phosphate compound or a phosphazene compound is preferably used. These organic phosphorus flame retardants have a plasticizing effect, and are therefore advantageous in that they can improve molding processability. As the aryl phosphate compound, various phosphate compounds known as conventional flame retardants can be used, but more preferably, one or more phosphate compounds represented by the following general formula (5) can be used.

(In the above formula, M represents a divalent organic group derived from a dihydric phenol, and Ar ¹ , Ar ² , Ar ³ , and Ar ⁴ each represent a monovalent organic group derived from a monohydric phenol. a, b, c, and d each independently represent 0 or 1, and m is an integer from 0 to 5. In the case of a mixture of phosphate esters having different degrees of polymerization m, m represents the average value thereof and is a value from 0 to 5.)

The phosphate compound of the above formula may be a mixture of compounds having different m numbers. In such a mixture, the average m number is preferably in the range of 0.5 to 1.5, more preferably 0.8 to 1.2, even more preferably 0.95 to 1.15, and particularly preferably 1 to 1.14.

Specific examples of suitable dihydric phenols from which M can be derived include hydroquinone, resorcinol, bis(4-hydroxydiphenyl)methane, bisphenol A, dihydroxydiphenyl, dihydroxynaphthalene, bis(4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl)ketone, and bis(4-hydroxyphenyl)sulfide, with resorcinol, bisphenol A, and dihydroxydiphenyl being particularly preferred.

Specific preferred examples of the monohydric phenol from which Ar ¹ , Ar ² , Ar ³ , and Ar ⁴ are derived include phenol, cresol, xylenol, isopropylphenol, butylphenol, and p-cumylphenol, and among these, phenol and 2,6-dimethylphenol are preferred.

Furthermore, such monohydric phenols may be substituted with halogen atoms, and specific examples of phosphate compounds having groups derived from such monohydric phenols include tris(2,4,6-tribromophenyl)phosphate, tris(2,4-dibromophenyl)phosphate, and tris(4-bromophenyl)phosphate.

On the other hand, specific examples of phosphate compounds not substituted with halogen atoms include monophosphate compounds such as triphenyl phosphate and tri(2,6-xylyl)phosphate, as well as phosphate oligomers based on resorcinol bis(di(2,6-xylyl)phosphate), phosphate oligomers based on 4,4-dihydroxydiphenyl bis(diphenyl phosphate), and phosphate ester oligomers based on bisphenol A bis(diphenyl phosphate). (Here, "based on" means that it may contain small amounts of other components with different degrees of polymerization, and more preferably, the component where m = 1 in formula (5) above accounts for 80% by weight or more, more preferably 85% by weight or more, and even more preferably 90% by weight or more.)

While various phosphazene compounds known as flame retardants can be used, phosphazene compounds represented by the following general formulas (6) and (7) are preferred.

(In the formula, X ¹ , X ² , X ³ , and X ⁴ represent hydrogen, a hydroxyl group, an amino group, or an organic group that does not contain a halogen atom, and r represents an integer of 3 to 10.)

In the above formulas (6) and (7), examples of the organic groups not containing a halogen atom represented by ^X1 , ^X2 , ^X3 , and ^X4 include an alkoxy group, a phenyl group, an amino group, an allyl group, etc. Among these, a cyclic phosphazene compound represented by the above formula (6) is preferred, and further, a cyclic phenoxyphosphazene in which ^X1 and ^X2 in the above formula (6) are phenoxy groups is particularly preferred.

The content of the organophosphorus flame retardant is preferably 1 to 50 parts by weight, more preferably 2 to 30 parts by weight, and even more preferably 5 to 20 parts by weight, per 100 parts by weight of Component A. If the amount of organophosphorus flame retardant is less than 1 part by weight, it will be difficult to achieve flame retardant effects, while if it exceeds 50 parts by weight, problems such as strand breakage and surging may occur during kneading and extrusion, resulting in reduced productivity.

(iii) Silicone-based flame retardants Silicone compounds used as silicone-based flame retardants improve flame retardancy through a chemical reaction during combustion. Various compounds previously proposed as flame retardants for aromatic polycarbonate resins can be used as such compounds. Silicone compounds are believed to impart a high flame retardant effect, particularly when used with polycarbonate resins, by bonding with themselves or with components derived from the resin during combustion to form a structure, or by a reduction reaction during the formation of this structure.

Therefore, it is preferable for the silicone to contain groups that are highly active in such reactions, and more specifically, it is preferable for the silicone to contain a predetermined amount of at least one type of group selected from alkoxy groups and hydrogen (i.e., Si-H groups). The content of such groups (alkoxy groups, Si-H groups) is preferably in the range of 0.1 to 1.2 mol/100g, more preferably 0.12 to 1 mol/100g, and even more preferably 0.15 to 0.6 mol/100g. This ratio can be determined by measuring the amount of hydrogen or alcohol generated per unit weight of silicone compound using the alkaline decomposition method. The alkoxy group is preferably an alkoxy group with 1 to 4 carbon atoms, with methoxy groups being particularly preferred.

Generally, the structure of a silicone compound is formed by any combination of the following four types of siloxane units. That is, M units: monofunctional siloxane units such as ( _CH3 ) _{3SiO1/2 ,} H( _CH3 ) _{2SiO1/ 2} , _H2 ( _CH3 )SiO1 _/ 2, ( _CH3 ) ₂ ( _CH2 =CH)SiO1 _{/ 2} , ( _CH3 ) ₂ ( _C6H5 )SiO1 _{/ 2} , ( _CH3 )( _C6H5 )( _CH2 =CH)SiO1 _/2 ; D units: difunctional siloxane units such as ( _CH3 ) _2SiO , H( _CH3 )SiO, _H2SiO , H( _{C6H5 )} SiO, ( _CH3 )( _CH2 = _CH )SiO, ( _C6H5 ) _2SiO ; T units: ( _{CH3 Q unit : a tetrafunctional siloxane} unit _{represented by SiO 2 .}

Specific examples of the structures of silicone compounds used in silicone-based flame retardants include rational formulas Dn, Tp, MmDn, MmTp, MmQq, MmDnTp, MmDnQq, MmTpQq, MmDnTpQq, DnTp, DnQq, and DnTpQq. Among these, preferred silicone compound structures are MmDn, MmTp, MmDnTp, and MmDnQq, with MmDn or MmDnTp being even more preferred.

Here, the coefficients m, n, p, and q in the rational formula are integers of 1 or greater that represent the degree of polymerization of each siloxane unit, and the sum of the coefficients in each rational formula is the average degree of polymerization of the silicone compound. This average degree of polymerization is preferably in the range of 3 to 150, more preferably 3 to 80, even more preferably 3 to 60, and particularly preferably 4 to 40. The more preferred the range, the better the flame retardancy. Furthermore, as described below, silicone compounds containing a predetermined amount of aromatic groups also exhibit excellent transparency and hue, resulting in excellent reflected light. Furthermore, when any of m, n, p, and q is a value of 2 or greater, the siloxane unit with that coefficient can be two or more types of siloxane units with different bonded hydrogen atoms or organic residues.

Silicone compounds may be linear or branched. Furthermore, the organic residue bonded to the silicon atom preferably has 1 to 30 carbon atoms, more preferably 1 to 20. Specific examples of such organic residues include alkyl groups such as methyl, ethyl, propyl, butyl, hexyl, and decyl; cycloalkyl groups such as cyclohexyl; aryl groups such as phenyl; and aralkyl groups such as tolyl. Alkyl groups, alkenyl groups, and aryl groups having 1 to 8 carbon atoms are even more preferred. Among alkyl groups, alkyl groups having 1 to 4 carbon atoms, such as methyl, ethyl, and propyl, are particularly preferred. Furthermore, silicone compounds used as silicone flame retardants preferably contain aryl groups. On the other hand, silane and siloxane compounds used as organic surface treatment agents for titanium dioxide pigments are clearly distinguished from silicone flame retardants in their preferred aspects, in that the absence of aryl groups provides more favorable effects. Silicone compounds used as silicone flame retardants may contain reactive groups in addition to the Si-H groups and alkoxy groups. Examples of such reactive groups include amino groups, carboxy groups, epoxy groups, vinyl groups, mercapto groups, and methacryloxy groups.

The content of the silicone flame retardant is preferably 0.01 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, and even more preferably 1 to 5 parts by weight, per 100 parts by weight of Component A.

(iv) Polytetrafluoroethylene having fibril-forming ability (fibrillated PTFE)
The fibrillated PTFE may be fibrillated PTFE alone or in a mixed form, i.e., a polytetrafluoroethylene-based mixture consisting of fibrillated PTFE particles and an organic polymer. Fibrillated PTFE has an extremely high molecular weight and tends to bond PTFE molecules together to form fibers under external influences such as shear force. Its number-average molecular weight is in the range of 1.5 million to tens of millions. The lower limit is more preferably 3 million. This number-average molecular weight is calculated based on the melt viscosity of polytetrafluoroethylene at 380°C, as disclosed, for example, in Japanese Patent Laid-Open Publication No. 6-145520. That is, the melt viscosity of fibrillated PTFE at 380°C, measured using the method described in this publication, is in the range of ¹⁰ to ¹⁰ poise, preferably ¹⁰ to ¹⁰ poise. Such PTFE can be used in the form of a solid or an aqueous dispersion. Furthermore, such fibrillated PTFE can be used in the form of a PTFE mixture with other resins to improve dispersibility in resins and to obtain better flame retardancy and mechanical properties.

Furthermore, as disclosed in Japanese Patent Application Laid-Open No. 6-145520, a structure with such fibrillated PTFE as a core and low-molecular-weight polytetrafluoroethylene as a shell is also preferably used.

Commercially available examples of such fibrillated PTFE include Teflon (registered trademark) 6J from DuPont-Mitsui Fluorochemicals Co., Ltd., and Polyflon MPA FA500 and F-201L from Daikin Chemical Industries, Ltd.

Fibrillated PTFE in a mixed form can be obtained by (1) mixing an aqueous dispersion of fibrillated PTFE with an aqueous dispersion or solution of an organic polymer and co-precipitation to obtain a co-aggregated mixture (methods described in JP-A-60-258263, JP-A-63-154744, etc.), (2) mixing an aqueous dispersion of fibrillated PTFE with dried organic polymer particles (method described in JP-A-4-272957), or (3) uniformly mixing an aqueous dispersion of fibrillated PTFE with an organic polymer particle solution and extracting the co-aggregated mixture from the mixture. (3) a method in which the media are simultaneously removed (methods described in JP-A Nos. 06-220210 and 08-188653, etc.); (4) a method in which a monomer that forms an organic polymer is polymerized in an aqueous dispersion of fibrillated PTFE (method described in JP-A No. 9-95583); and (5) a method in which an aqueous dispersion of PTFE and an organic polymer dispersion are uniformly mixed, and then a vinyl monomer is polymerized in the mixed dispersion, and then a mixture is obtained (methods described in JP-A No. 11-29679, etc.).

Commercially available products of these mixed forms of fibrillated PTFE include the Metablen A series, represented by Mitsubishi Rayon Co., Ltd.'s "Metablen A3000" (trade name), "Metablen A3700" (trade name), and "Metablen A3800" (trade name), Shine Polymer's SN3300B7 (trade name), and GE Specialty Chemicals' "BLENDEX B449" (trade name).

The proportion of fibrillated PTFE in the blend is preferably 1% to 95% by weight, more preferably 10% to 90% by weight, and most preferably 20% to 80% by weight, per 100% by weight of the blend.

When the proportion of fibrillated PTFE in the blend is within this range, good dispersibility of the fibrillated PTFE can be achieved. The content of fibrillated PTFE is preferably 0.001 to 0.5 parts by weight, more preferably 0.01 to 0.5 parts by weight, and even more preferably 0.1 to 0.5 parts by weight, per 100 parts by weight of Component A.

(III) Dyes and Pigments The thermoplastic resin composition of the present invention can further contain various dyes and pigments to provide molded articles with diverse design properties. Examples of dyes and pigments that can be used in the present invention include perylene dyes, coumarin dyes, thioindigo dyes, anthraquinone dyes, thioxanthone dyes, ferrocyanides such as Prussian blue, perinone dyes, quinoline dyes, quinacridone dyes, dioxazine dyes, isoindolinone dyes, and phthalocyanine dyes. Furthermore, the thermoplastic resin composition of the present invention can be blended with a metallic pigment to achieve better metallic colors. Aluminum powder is a suitable metallic pigment. Furthermore, blending a fluorescent brightener or other fluorescent dye that emits light can provide even better design effects that take advantage of the emitted light color.

(IV) Fluorescent Brightening Agent In the thermoplastic resin composition of the present invention, the fluorescent brightening agent is not particularly limited as long as it is used to improve the color tone of the resin or the like to white or bluish white. Examples include stilbene-based, benzimidazole-based, benzoxazole-based, naphthalimide-based, rhodamine-based, coumarin-based, and oxazine-based compounds. Specific examples include CI Fluorescent Brightener 219:1, Eastman Chemical Company's EASTOBRITE OB-1, and Showa Chemical Co.'s "HAKKOL PSR." Here, the fluorescent brightening agent has the effect of absorbing the ultraviolet energy of light and radiating this energy in the visible region. The content of the fluorescent brightening agent is preferably 0.001 to 0.1 parts by weight, more preferably 0.001 to 0.05 parts by weight, per 100 parts by weight of Component A. Even if the content exceeds 0.1 part by weight, the effect of improving the color tone of the composition is small.

(V) Compounds Absorbing Heat Rays The thermoplastic resin composition of the present invention may contain a compound capable of absorbing heat rays. Suitable examples of such compounds include phthalocyanine-based near-infrared absorbers, metal oxide-based near-infrared absorbers such as ATO, ITO, iridium oxide, ruthenium oxide, immonium oxide, and titanium oxide, various metal compounds with excellent near-infrared absorption capabilities, such as metal boride-based and tungsten oxide-based near-infrared absorbers such as lanthanum boride, cerium boride, and tungsten boride, and carbon fillers. Examples of such phthalocyanine-based near-infrared absorbers include MIR-362 manufactured by Mitsui Chemicals, Inc., which is commercially available and easily available. Examples of carbon fillers include carbon black, graphite (both natural and artificial), and fullerenes, with carbon black and graphite being preferred. These can be used alone or in combination of two or more. The content of the phthalocyanine-based near-infrared absorbent is preferably 0.0005 to 0.2 parts by weight, more preferably 0.0008 to 0.1 parts by weight, and even more preferably 0.001 to 0.07 parts by weight, relative to 100 parts by weight of Component A. The contents of the metal oxide-based near-infrared absorbent, metal boride-based near-infrared absorbent, and carbon filler in the thermoplastic resin composition of the present invention are preferably in the range of 0.1 to 200 ppm (weight ratio), and more preferably 0.5 to 100 ppm.

(VI) Light Diffusers The thermoplastic resin composition of the present invention can be blended with a light diffuser to impart a light diffusing effect. Examples of such light diffusers include polymeric fine particles, inorganic fine particles with a low refractive index such as calcium carbonate, and composites thereof. Such polymeric fine particles are already known as light diffusers for polycarbonate resins. More preferred examples include acrylic crosslinked particles with a particle size of several microns and silicone crosslinked particles such as polyorganosilsesquioxane. Examples of the shape of the light diffuser include spherical, discoidal, cylindrical, and irregular shapes. Such spherical shapes do not necessarily need to be perfect spheres and include deformed shapes, and such cylindrical shapes include cubes. Preferred light diffusers are spherical, and the more uniform their particle size, the better. The content of the light diffuser is preferably 0.005 to 20 parts by weight, more preferably 0.01 to 10 parts by weight, and even more preferably 0.01 to 3 parts by weight per 100 parts by weight of Component A. Two or more light diffusers can be used in combination.

(VII) Highly Light-Reflecting White Pigment A highly light-reflecting white pigment can be blended into the thermoplastic resin composition of the present invention to impart a light-reflecting effect. Titanium dioxide (particularly titanium dioxide treated with an organic surface treatment agent such as silicone) is particularly preferred as such a white pigment. The content of such highly light-reflecting white pigment is preferably 3 to 30 parts by weight, more preferably 8 to 25 parts by weight, per 100 parts by weight of Component A. Two or more types of highly light-reflecting white pigments can be used in combination.

(VIII) Ultraviolet Absorber The thermoplastic resin composition of the present invention can be blended with an ultraviolet absorber to impart weather resistance. Specific examples of such ultraviolet absorbers include benzophenone-based ones, such as 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-benzyloxybenzophenone, 2-hydroxy-4-methoxy-5-sulfoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxy-5-sodium sulfoxybenzophenone, bis(5-benzoyl-4-hydroxy-2-methoxyphenyl)methane, 2-hydroxy-4-n-dodecyloxybenzophenone, and 2-hydroxy-4-methoxy-2'-carboxybenzophenone. Specific examples of the ultraviolet absorber include benzotriazole-based compounds such as 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole, 2-(2-hydroxy-3,5-dicumylphenyl)phenylbenzotriazole, 2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorobenzotriazole, 2,2'-methylenebis[ 4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol], 2-(2-hydroxy-3,5-di-tert-butylphenyl)benzotriazole, 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2-hydroxy-3,5-di-tert-amylphenyl)benzotriazole, 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole Examples of the 2-hydroxyphenyl-2H-benzotriazole skeleton include 2-(2-hydroxy-5-acryloxyethylphenyl)benzotriazole, 2-(2-hydroxy-5-tert-butylphenyl)benzotriazole, 2-(2-hydroxy-4-octoxyphenyl)benzotriazole, 2,2'-methylenebis(4-cumyl-6-benzotriazolephenyl), 2,2'-p-phenylenebis(1,3-benzoxazin-4-one), and 2-[2-hydroxy-3-(3,4,5,6-tetrahydrophthalimidomethyl)-5-methylphenyl]benzotriazole, and polymers having a 2-hydroxyphenyl-2H-benzotriazole skeleton such as copolymers of 2-(2'-hydroxy-5-methacryloxyethylphenyl)-2H-benzotriazole and vinyl monomers copolymerizable with the monomer, and copolymers of 2-(2'-hydroxy-5-acryloxyethylphenyl)-2H-benzotriazole and vinyl monomers copolymerizable with the monomer. Specific examples of hydroxyphenyltriazine ultraviolet absorbers include 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-hexyloxyphenol, 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-methyloxyphenol, 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-ethyloxyphenol, 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-propyloxyphenol, and 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-butyloxyphenol. Further examples include compounds in which the phenyl group of the above-mentioned compounds is replaced with a 2,4-dimethylphenyl group, such as 2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl)-5-hexyloxyphenol. Specific examples of cyclic iminoester-based ultraviolet absorbers include 2,2'-p-phenylenebis(3,1-benzoxazin-4-one), 2,2'-m-phenylenebis(3,1-benzoxazin-4-one), and 2,2'-p,p'-diphenylenebis(3,1-benzoxazin-4-one). Specific examples of cyanoacrylate-based ultraviolet absorbers include 1,3-bis-[(2'-cyano-3',3'-diphenylacryloyl)oxy]-2,2-bis[(2-cyano-3,3-diphenylacryloyl)oxy]methyl)propane and 1,3-bis-[(2-cyano-3,3-diphenylacryloyl)oxy]benzene. Furthermore, the UV absorber may be a polymeric UV absorber obtained by copolymerizing such a UV-absorbing monomer and/or a photostable monomer with a monomer such as an alkyl (meth)acrylate by adopting a radically polymerizable monomer compound structure. Suitable examples of the UV-absorbing monomer include compounds containing a benzotriazole skeleton, a benzophenone skeleton, a triazine skeleton, a cyclic imino ester skeleton, and a cyanoacrylate skeleton in the ester substituent of a (meth)acrylic acid ester. Among these, benzotriazole-based and hydroxyphenyl triazine-based compounds are preferred in terms of UV absorption ability, while cyclic imino ester-based and cyanoacrylate-based compounds are preferred in terms of heat resistance and color. Specific examples include "Chemisorb 79" from Chemipro Chemical Co., Ltd. and "Tinuvin 234" from BASF Japan Ltd. The UV absorbers may be used alone or in a mixture of two or more types.

The content of the ultraviolet absorber is preferably 0.01 to 3 parts by weight, more preferably 0.01 to 1 part by weight, even more preferably 0.05 to 1 part by weight, and especially preferably 0.05 to 0.5 parts by weight, per 100 parts by weight of Component A.

(IX) Antistatic Agent: The thermoplastic resin composition of the present invention may require antistatic properties. In such cases, it is preferable to include an antistatic agent. Examples of such antistatic agents include (1) organic sulfonate phosphonium salts, such as arylsulfonate phosphonium salts (e.g., dodecylbenzenesulfonate phosphonium salt) and alkylsulfonate phosphonium salts, as well as borate phosphonium salts, such as tetrafluoroborate phosphonium salt. The content of the phosphonium salt is preferably 5 parts by weight or less, preferably 0.05 to 5 parts by weight, more preferably 1 to 3.5 parts by weight, and even more preferably 1.5 to 3 parts by weight, per 100 parts by weight of Component A. Examples of antistatic agents include (2) alkali (earth) metal organic sulfonates, such as lithium organic sulfonate, sodium organic sulfonate, potassium organic sulfonate, cesium organic sulfonate, rubidium organic sulfonate, calcium organic sulfonate, magnesium organic sulfonate, and barium organic sulfonate. As mentioned above, such metal salts are also used as flame retardants. More specific examples of such metal salts include metal salts of dodecylbenzenesulfonic acid and metal salts of perfluoroalkanesulfonic acid. The content of the alkali (earth) metal organic sulfonate is suitably 0.5 parts by weight or less, preferably 0.001 to 0.3 parts by weight, and more preferably 0.005 to 0.2 parts by weight, per 100 parts by weight of Component A. Alkali metal salts such as potassium, cesium, and rubidium are particularly suitable.

Examples of antistatic agents include (3) organic ammonium sulfonates, such as ammonium alkylsulfonates and ammonium arylsulfonates. The amount of such ammonium salts is preferably 0.05 parts by weight or less per 100 parts by weight of the components A and B. Examples of antistatic agents include (4) polymers containing a poly(oxyalkylene) glycol component, such as polyether ester amide. The amount of such polymers is preferably 5 parts by weight or less per 100 parts by weight of component A.

(X) Filler The thermoplastic resin composition of the present invention can be blended with various fillers known as reinforcing fillers other than fibrous fillers. Various plate-like fillers and granular fillers can be used as such fillers. Here, plate-like fillers are fillers that have a plate-like shape (including those with an uneven surface or curved plates). Granular fillers are fillers with shapes other than these, including irregular shapes.

Preferred examples of plate-like fillers include glass flakes, talc, mica, kaolin, metal flakes, carbon flakes, and graphite, as well as plate-like fillers coated with a different material such as a metal or metal oxide. The particle size preferably ranges from 0.1 to 300 μm. This particle size refers to the median diameter (D50) of the particle size distribution measured by X-ray transmission, a type of liquid-phase precipitation method, in the range up to approximately 10 μm; the median diameter (D50) of the particle size distribution measured by laser diffraction/scattering in the range from 10 to 50 μm; and the value measured by vibrating sieving in the range from 50 to 300 μm. These particle sizes are those within the resin composition. The plate-like filler may be surface-treated with various coupling agents such as silane-based, titanate-based, aluminate-based, and zirconate-based agents, or may be bundled or compressed with various resins such as olefin-based resins, styrene-based resins, acrylic resins, polyester-based resins, epoxy-based resins, and urethane-based resins, or higher fatty acid esters.

(XI) Other Resins and Elastomers The thermoplastic resin composition of the present invention may contain a small amount of other resins or elastomers, replacing part of the resin component, as long as the effects of the present invention are not impaired. The amount of the other resins or elastomers added is preferably 20 parts by weight or less, more preferably 10 parts by weight or less, even more preferably 5 parts by weight or less, and most preferably 3 parts by weight or less, per 100 parts by weight of Component A. Examples of such other resins include polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyamide resins, polyimide resins, polyetherimide resins, polyurethane resins, silicone resins, polyphenylene ether resins, polyphenylene sulfide resins, polysulfone resins, polymethacrylate resins, phenolic resins, and epoxy resins. Examples of elastomers include isobutylene/isoprene rubber, styrene/butadiene rubber, ethylene/propylene rubber, acrylic elastomers, polyester elastomers, polyamide elastomers, and core-shell elastomers such as MBS (methyl methacrylate/styrene/butadiene) rubber, MB (methyl methacrylate/butadiene) rubber, and MAS (methyl methacrylate/acrylonitrile/styrene) rubber.

(XII) Other Additives The thermoplastic resin composition of the present invention may contain other flow improvers, antibacterial agents, dispersants such as liquid paraffin, photocatalytic antifouling agents, photochromic agents, and the like.

<Production of Resin Composition>
Any method can be used to produce the resin composition of the present invention. For example, component A, component B, and optionally other components can be thoroughly mixed using a premixing device such as a V-type blender, Henschel mixer, mechanochemical device, or extrusion mixer, followed by granulation using an extrusion granulator or briquetting machine, if necessary, followed by melt-kneading using a melt mixer such as a vented twin-screw extruder, and pelletization using a pelletizer or other device. Other methods include feeding component A, component B, and optionally other components independently to a melt mixer such as a vented twin-screw extruder, or premixing a portion of component A and the other components and then feeding the premixer independently of the remaining components. If any of the components to be blended is liquid, a liquid injection device or liquid addition device can be used to feed the components to the melt mixer.

<Metal molded body>
The metal material forming the resin-metal composite molded body of the present invention is preferably a metal material having a joint with a groove formed therein, and more preferably a metal material in which the groove is formed by irradiation with continuous wave laser light or pulsed wave laser light. The metal constituting the metal material is not particularly limited and can be appropriately selected from known metals depending on the application. Examples include iron, various stainless steels, aluminum or its alloys, copper, magnesium, and alloys containing these. Among these, aluminum (aluminum alone) and aluminum alloys are preferred, and aluminum alloys are more preferred, in terms of light weight and high strength. Metal molded bodies are formed by cutting, plastic processing such as pressing, punching, grinding, polishing, electrical discharge machining, and other thinning processes, into shapes such as flat plates, curved plates, rods, cylinders, and blocks. The surface of the metal molded body preferably has a large surface area to improve adhesion to the resin, and specifically, a roughened surface is preferred. The method for roughening the surface of a metal component is preferably a method of roughening the surface by a means selected from a chemical etching method using a known etching agent, irradiation with laser light, etching processing, press processing, and blast processing, and more preferably a method of roughening the surface by irradiation with continuous wave laser light or pulse wave laser light.

<Preparation of resin-metal composite molded body>
The resin-metal composite molded product of the present invention is a composite molded product characterized in that the metal material and the resin molded product are bonded together by the resin molded product entering the grooves of the metal material. The method for producing the composite molded product is not particularly limited, and examples include resin molding methods such as injection molding, extrusion molding, hot press molding, compression molding, transfer molding, laser welding molding, reaction injection molding (RIM molding), rim molding (LIM molding), and thermal spray molding. Among these, a manufacturing method including a step of irradiating a joining surface of a metal molded product with continuous wave laser light or pulse wave laser light and a step of injection molding a thermoplastic resin composition in a mold, in which a portion of the metal molded product irradiated with continuous wave laser light or pulse wave laser light in the previous step, including the joining surface, is preferred from the standpoint of shape flexibility and productivity. Furthermore, when producing a composite comprising an aluminum resin composition film coated on an aluminum surface, examples of the method include a coating method in which the resin composition is dissolved or dispersed in a solvent and applied, as well as various other painting methods. Other painting methods include baking coating, electrodeposition coating, electrostatic coating, powder coating, and UV-curable coating.

<Electronic control device>
The resin-metal composite molded product of the present invention is preferably used in a control device having a circuit board on which electronic components are mounted, a base having protrusions for installing the circuit board, and a cover formed of resin and covering the circuit board and the base. Furthermore, it is more preferable that the protrusions of the base consist solely of the thermoplastic resin composition of the present application. Furthermore, it is preferable that the base have protrusions and the cover have multiple holes in order to suppress heat generation in the electronic circuit board.

The thermoplastic resin composition of the present invention, which contains an appropriate amount of expanded graphite, is a thermoplastic resin composition that, when bonded to a metal, has excellent adhesion to the metal and exhibits excellent durability with minimal reduction in bond strength after heat cycle testing when bonded to a metal in a composite molded article. These technologies are not available in conventional resin-metal bonding technologies, and are extremely useful in a variety of industrial applications, including office automation equipment and electrical and electronic equipment, with significant industrial benefits.

The present inventors currently believe that the best form of the present invention embodies the preferred ranges of each of the above-mentioned requirements, and representative examples are described in the examples below. Naturally, the present invention is not limited to these forms.

The present invention will be further explained below with reference to examples, but is not limited thereto.
The evaluation was carried out on the following items.

(i) Adhesion Strength: Pellets obtained from each composition of the examples were dried in a hot air dryer at 100°C for 5 hours and then molded into test specimens for resin-metal adhesion tests conforming to ISO 19095-2 using an injection molding machine [Sumitomo Heavy Industries, Ltd. SG150U-S-M IV] at a cylinder temperature of 310°C and a mold temperature of 110°C. (170 mm length x 10 mm width x 4 mm thickness: butt joint type). The metal molded body used was an aluminum plate (thickness: 4 mm) of alloy number 5052 specified in JIS H4000 cut to dimensions of 85 mm x 10 mm, followed by laser-forming of a joint with grooves on the metal surface. The groove diameter was 40-80 μm, the depth was 75-125 μm, and the spacing between the grooves was 90-120 μm. The obtained test piece was conditioned for 24 hours under conditions of 23°C and 50% RH, and then the resin-metal adhesion strength (tensile strength using butt-jointed test pieces) was measured in accordance with ISO 19095-3. The adhesion strength is preferably 20 MPa or more.

(ii) Strength retention rate after heat cycle test A heat cycle test (2000 cycles, each cycle consisting of heating at 80°C for 30 minutes, followed by cooling at -40°C for 30 minutes) was carried out using the composite molded article used in "(i) Adhesion strength", and then the resin-metal adhesion strength (tensile strength of butt-jointed test pieces) was measured and the strength retention rate was calculated using the following formula (1). The strength retention rate is preferably 80% or more.

[Examples 1 to 12, Comparative Examples 1 to 5]
A resin composition having the blending ratios shown in Table 1 was prepared as follows. The following explanation follows the symbols in the table. Each component was weighed out according to the ratios shown in the table, and the components, excluding the fibrous filler, were mixed uniformly using a tumbler. The mixture was then fed into an extruder to prepare a resin composition. The extruder used was a vented twin-screw extruder, model TEX-30XSST (fully intermeshing, co-rotating, two-start screw) manufactured by The Japan Steel Works, Ltd. The extrusion conditions were a throughput rate of 20 kg/h, a screw rotation speed of 150 rpm, a vent vacuum of 3 kPa, and an extrusion temperature of 280-320°C. The fibrous filler was fed into the extruder through the second feed port using a side feeder, while the remaining polycarbonate resin and additives were fed into the extruder through the first feed port. The first feed port here refers to the feed port farthest from the die, and the second feed port refers to the feed port located between the extruder die and the first feed port. The pellets thus obtained were used to mold test pieces for evaluation using an injection molding machine as described above. The evaluation results are shown in Table 1. The components indicated by symbols in Table 1 are as follows:

(Component A)
A-1: Aromatic polycarbonate resin, Panlite L-1225WX (product name) manufactured by Teijin Limited
A-2: Polycarbonate-polydiorganosiloxane copolymer resin (viscosity average molecular weight 23,500, PDMS content 8.4%, PDMS polymerization degree 37)
A-3: Polyphenylene sulfide resin, manufactured by Polyplastics, C0202C7 (product name)
(B component)
B-1: Expanded graphite, manufactured by Nishimura Graphite Co., Ltd., E-40 (product name)
B-2 (for comparison): Flake graphite, SC-120 (product name) manufactured by Fuji Graphite Industries Co., Ltd.
(C component)
C-1: Glass fiber, Nittobo Co., Ltd., chopped strand CS3PE455FB (product name)
C-2: Carbon fiber, Teijin Limited HTC422 (product name)
(Other ingredients)
D-1: Stabilizer, Johoku Chemical Industry Co., Ltd. JC-224 (product name)
D-2: Weathering agent, Tinuvin 234 (product name) manufactured by BASF Japan Ltd.
D-3: Release agent, Rikemal SL-900 (product name) manufactured by Riken Vitamin Co., Ltd.
D-4: Colorant, RB90003S (product name) manufactured by Koshigaya Chemical Industry Co., Ltd.

Claims (8)

A thermoplastic resin composition for producing a resin molded body in a composite molded body in which a metal molded body and a resin molded body are joined, characterized in that the thermoplastic resin composition contains 1 to 80 parts by weight of (B) expanded graphite (component B) and 1 to 100 parts by weight of (C) a fibrous filler (component C) per 100 parts by weight of (A) a thermoplastic resin (component A). 2. The thermoplastic resin composition according to claim 1 , wherein component C is glass fiber and/or carbon fiber. A composite molded body in which a metal molded body having a groove portion on its surface and a resin molded body made of the thermoplastic resin composition described in claim 1 or 2 are joined together, characterized in that the metal molded body and the resin molded body are joined together by the resin molded body entering the groove portion. 4. The composite molding according to claim 3 , wherein the grooves on the surface of the metal molding are formed by irradiating the surface of the metal molding with a continuous wave laser beam or a pulse wave laser beam. A method for producing a composite molded body according to claim 3 or 4 , characterized in that it comprises a step of irradiating a joining surface of the metal molded body with continuous wave laser light or pulse wave laser light, and a step of placing a portion of the metal molded body including the joining surface irradiated with continuous wave laser light or pulse wave laser light in a mold and injection molding the thermoplastic resin composition according to claim 1 or 2 . 5. An electronic control device comprising: a circuit board on which electronic components are mounted; a base portion having protrusions for installing said circuit board; and a cover portion formed of resin and covering said circuit board and said base portion, wherein said base portion is the composite molded product according to claim 3 or 4 . 7. The electronic control device according to claim 6 , wherein the protrusions on the base are made of the thermoplastic resin composition according to claim 1 or 2 . 8. The electronic control device according to claim 6, wherein the cover portion has a plurality of holes.