JP6417644B1 - Thermally conductive resin composition and molded body - Google Patents

Abstract

The present invention provides a resin composition and a molded body that can form a molded body having good thermal conductivity and molding processability and good mechanical strength. A thermally conductive resin composition according to the present invention comprises a polyamide resin (A), an ethylene-α-olefin copolymer comprising a structural unit derived from ethylene and a structural unit derived from an α-olefin having 3 to 20 carbon atoms. It contains an acid-modified polymer (B) and an inorganic filler (C). The content ratio of the polyamide resin (A) and the acid-modified product of ethylene-α-olefin copolymer (B) is such that the polyamide resin (A) / acid-modified product of ethylene-α-olefin copolymer (B). = 70/30 to 95/5, and in 100% by mass of the total resin composition, the polyamide resin (A) is 10 to 40% by mass, and the acid-modified product (B) of the ethylene-α-olefin copolymer is 0. .6 to 17% by mass, and the inorganic filler (C) is 40 to 80% by mass. [Selection figure] None

Description

  The present invention relates to a polyamide resin, a resin composition containing an acid-modified product (B) of an ethylene-α-olefin copolymer and an inorganic filler (C), and a molded product.

  In recent years, in the field of electrical / electronic equipment, transmission signals have become higher in frequency due to advances in functionality, density, and compactness. Along with this, the amount of heat generated from components such as semiconductors, power supplies, and light sources is increasing, and heat dissipation measures are becoming very important for the stable operation of equipment. For this reason, as a heat dissipation measure, a sheet or member having high thermal conductivity that fills the gap between the heat generating part in the electric / electronic device and the heat dissipating part such as a heat sink may be installed.

  On the other hand, heat-dissipating members of electric / electronic devices are rapidly being replaced from metal materials by plastic materials that are advantageous in terms of lightness and electrical insulation. However, since the plastic material has lower thermal conductivity than inorganic materials such as metal materials, there is a problem of low heat dissipation. In order to solve such a problem, attempts have been made to increase the thermal conductivity by blending a large amount (30% by mass or more, sometimes 50% by mass or more) of a thermally conductive inorganic filler in the molded body.

  However, if a large amount of an inorganic filler is added to the resin composition material constituting the molded body, the melt viscosity of the resin composition increases, and the molding process cannot be performed in the subsequent process, or the molding processability is significantly reduced. End up. Moreover, even when a molded product is obtained, the molded body becomes very brittle. In addition, when the resin composition constituting the molded body contains a large amount of inorganic fillers and low molecular weight components, the molded body may be formed when the molten material is discharged from a die at a high speed by, for example, injection molding or extrusion molding. There is a problem that a skin layer in which the inorganic filler (C) is not present on the outermost surface or a skin layer with a small content of the inorganic filler (C) is formed, and the thermal conductivity is greatly impaired.

Patent Document 1 discloses a technique for performing a surface treatment on an inorganic filler as a measure for forming processability and embrittlement of a molded body.
Patent Document 2 discloses a resin composition containing an aromatic vinyl compound and a copolymer such as a conjugated diene compound, a thermoplastic elastomer, a paraffin softening agent, and a thermally conductive inorganic filler.
Patent Document 3 includes a predetermined amount of polyamide resin (A), magnesium compound (B), glass fiber (C), aliphatic metal salt, amide group-containing compound, and maleic anhydride group-containing compound. A resin composition containing one or more selected additives (D) is disclosed.
Patent Document 4 discloses a polyamide elastomer composition containing a predetermined amount of an inorganic filler, a silane coupling agent, and a polyamide elastomer.

Patent Document 5 discloses a matrix comprising at least one polyamide, at least one prepolymer, in which the ratio of the weight of the polyamide matrix to the total of the polyamide and the prepolymer and the ratio of the weight of the prepolymer are specific amounts. A molding resin composition excellent in impact resistance, fluidity, and the like, each containing a specific amount of a polymer, at least one impact resistance improver, and an additive is described.
Patent Document 6 discloses a thermoplastic molding material containing a specific amount of thermoplastic polyamide, red phosphorus, dialkylphosphinate, an ethylene copolymer which is an impact modifier having a specific structure, talc, and further additives. Has been proposed.
Patent Document 7 discloses a modification comprising a semi-aromatic polyamide resin (A) having a melting point in a specific range, a semi-aromatic polyamide resin (B) having a heat of fusion in a specific range, and a functional group structural unit containing a hetero atom. A semi-aromatic polyamide resin composition containing specific amounts of an olefin polymer (C), a fibrous filler (D), and a specific fatty acid metal salt (E) is disclosed (Claim 1).
Patent Document 8 includes (a) at least one semicrystalline polyamide; (b) carbon fibers having a specific fiber diameter; (c) at least one particulate mineral or salt filler; (d) specific Polyamide molding materials have been proposed, each having a specific amount of at least one amorphous polymer having Tg; (e) carbon black; (f) at least one further additive and / or additive.

JP2015-025025A JP 2005-75895 A Japanese Patent Laying-Open No. 2015-036415 Japanese Patent Laying-Open No. 2015-057466 Special table 2017-5050963 gazette Japanese translation of patent publication No.16-515656 JP 2006-138163 A JP-A-2015-199959

  In the market, there is a strong demand for the development of a resin composition that has excellent thermal conductivity and good molding processability, and has excellent molding processability even when it contains a large amount of an inorganic filler. However, for example, the resin composition of Patent Document 1 does not provide a high thermal conductivity to a molded product, and the physical properties and recyclability of the heat conductivity are not sufficient. Has a problem that the mechanical properties of the molded product are not sufficient.

  The present invention has been made in view of the above background, has excellent thermal conductivity and good moldability, and particularly when a large amount (for example, 50% by mass or more) of an inorganic filler is contained, An object of the present invention is to provide a resin composition and a molded article that are excellent in molding processability, for example, an injection molded article from which a good molded article excellent in smoothness, mechanical properties and thermal conductivity can be obtained.

As a result of intensive studies to solve the above problems, the present inventors have completed the present invention.
[1]: Polyamide resin (A),
A resin composition comprising an acid-modified product (B) of an ethylene-α-olefin copolymer containing a structural unit derived from ethylene and a structural unit derived from an α-olefin having 3 to 20 carbon atoms and an inorganic filler (C). Yes,
The content ratio of the polyamide resin (A) and the acid-modified product (B) of ethylene-α-olefin copolymer is polyamide resin (A) / acid-modified product of ethylene-α-olefin copolymer (B) = 70. / 30 to 95/5,
Of the total 100% by mass of the resin composition, the polyamide resin (A) is 10 to 40% by mass, the acid-modified product (B) of the ethylene-α-olefin copolymer is 0.6 to 17% by mass, and the inorganic filler ( C) is 40-80% by weight,
However, the case where the acid-modified product (B) of the ethylene-α-olefin copolymer is a maleic anhydride-modified product of ethylene-octene copolymer and the inorganic filler (C) is inorganic particles is excluded. ,
Thermally conductive resin composition.
[2]: The thermally conductive resin composition according to [1], wherein the inorganic filler (C) is a particle that may have a coating layer.
[3]: The heat conductive resin composition according to [1] or [2], wherein the inorganic filler (C) has an average particle size of 0.1 to 50 μm.
[4]: The thermal conductivity according to any one of [1] to [3], wherein the acid-modified product (B) of the ethylene-α-olefin copolymer has a weight average molecular weight of 70,000 to 500,000. Resin composition.
[5] The thermal conductive resin composition according to any one of [1] to [4], wherein the inorganic filler (C) has a thermal conductivity of 5 W / mK or more.
[6]: A molded article obtained by molding the thermally conductive resin composition according to any one of [1] to [5].
[7]: The molded article according to [6], wherein the thermal conductivity measured by a hot disk method is 1.1 W / mK or more.

  According to the present invention, the thermal conductivity is excellent, and the molding processability is also good. In particular, even when an inorganic filler is contained in a large amount (for example, 50% by mass or more), the molding processability is excellent. The product has an excellent effect that it can provide a resin composition and a molded product from which a good molded product excellent in smoothness, mechanical properties and thermal conductivity can be obtained.

  Hereinafter, an example of an embodiment to which the present invention is applied will be described. The numerical values specified in this specification are values obtained by the method disclosed in the embodiment or examples. It should be noted that other embodiments are also included in the scope of the present invention as long as they meet the spirit of the present invention. In addition, the numerical values “A to B” specified in the present specification refer to ranges satisfying the numerical value A and the value larger than the numerical value A and the numerical value B and the value smaller than the numerical value B.

  The resin composition of this embodiment contains a polyamide resin (A), an acid-modified product (B) of an ethylene-α-olefin copolymer, and an inorganic filler (C).

<Polyamide resin (A)>
The polyamide resin (A) is not particularly limited as long as it has an amide bond.
Examples of the polyamide resin (A) include polyamide 6, polyamide 66, polyamide 46, polyamide 11, polyamide 12, polyamide 69, polyamide 610, polyamide 612, polyamide 96, amorphous polyamide, high melting point polyamide, polyamide RIM, polyamide MIX6 and the like; copolymers containing two or more monomers constituting the polyamide, terephthalic acid copolymers such as polyamide 6T and polyamide 9T, that is, polyamide 6/66 copolymer, polyamide 6/66/610 Examples thereof include a copolymer, a polyamide 6/66/11/12 copolymer, and a crystalline polyamide / non-crystalline polyamide copolymer. A polyamide resin is used individually by 1 type or in mixture of 2 or more types. Among these, polyamide 6 and polyamide 12 having low crystallinity and high impact resistance are particularly preferable.

  The resin composition according to the present embodiment may contain other resin in the polyamide resin (A). That is, a mixed polymer obtained by mixing the polyamide resin (A) and another resin may be used. Examples of such mixed polymers include polyamide / polyester mixed polymers, polyamide / polyphenylene oxide mixed polymers, polyamide / polycarbonate mixed polymers, polyamide / polyolefin mixed polymers, polyamide / styrene / acrylonitrile mixed polymers, polyamide / polyesters. Acrylic ester mixed polymer, polyamide / silicone mixed polymer and the like can be mentioned.

  It is preferable that polyamide resin (A) is 10-40 mass% in 100 mass% of the whole resin composition, More preferably, it is 10-38 mass%, More preferably, it is 20-35 mass%. By setting it as 40 mass% or less, it becomes possible to increase the quantity of an inorganic filler (C), and can improve thermal conductivity. When other resins are contained, the content of other resins is preferably 20% by mass or less, and more preferably 10% by mass or less, in 100% by mass of the entire resin composition.

<Acid modified product of ethylene-α-olefin copolymer (B)>
The acid-modified product (B) of an ethylene-α-olefin copolymer is an ethylene-α-olefin copolymer acid containing a structural unit derived from ethylene and a structural unit derived from an α-olefin having 3 to 20 carbon atoms. It is a modified product (B). The ethylene-α-olefin copolymer may contain a structural unit derived from another monomer without departing from the gist of the present invention. For example, conjugated dienes such as 1,3-butadiene and 2-methyl-1,3-butadiene; non-conjugated dienes such as 1,4-pentadiene and 1,5-hexadiene; unsaturated carboxylic acids such as acrylic acid and methacrylic acid Unsaturated carboxylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, and ethyl methacrylate; structural units derived from monomers of vinyl ester compounds such as vinyl acetate may be included. In the acid-modified product (B), the structural unit derived from ethylene and the structural unit derived from an α-olefin having 3 to 20 carbon atoms are preferably 50 mol% or more, and more preferably 80 mol% or more. Moreover, the ethylene-alpha-olefin copolymer which consists of a structural unit derived from ethylene and a structural unit derived from a C3-C20 alpha olefin is preferable.

  The carbon number of the α-olefin in the acid-modified product (B) of the ethylene-α-olefin copolymer is 3 to 20. By setting it as this range, the improvement effect of the mechanical property of a resin composition is acquired. More preferably, it is 6-20, More preferably, it is 6-10.

  Specific examples of the α-olefin include propylene, 1-butene, 1-pentene, 4-methyl-pentene-1, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene and 1-undecene. 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-icocene, styrene, p-methylstyrene, and the like. Of these, 4-methyl-1-pentene, 1-hexene, 1-heptene and 1-octene are preferable, and 4-methyl-1-pentene, 1-hexene and 1-octene are more preferable. These compounds can be used individually by 1 type or in combination of 2 or more types.

  The ethylene content in all structural units of the main chain of the acid-modified product (B) of the ethylene-α-olefin copolymer is preferably 30 to 99.5 mol%, and more preferably 50 to 95 mol%. More preferred. The content of α-olefin in all structural units of the main chain of the acid-modified product (B) of the ethylene-α-olefin copolymer is preferably 0.5 to 70 mol%, preferably 5 to 50 mol%. It is more preferable that By setting the content of α-olefin in all structural units of the main chain of the acid anhydride (B) to 0.5 to 70 mol%, the properties relating to moldability become more excellent.

  As the acid that modifies the copolymer, an unsaturated carboxylic acid-containing compound or a derivative thereof is preferably used. Examples include maleic acid, maleic anhydride, fumaric acid, fumaric anhydride, adipic acid, adipic anhydride, phthalic anhydride, glutaric anhydride, and malonic anhydride. These acids may be used alone or in combination of two or more. Of these, maleic anhydride and adipic acid are particularly preferable. As the acid anhydride (B) of the ethylene-α-olefin copolymer, one type may be used alone, or two or more types may be used in combination.

  The acid addition rate in the acid-modified product (B) of the ethylene-α-olefin copolymer is preferably 0.1 to 10% by mass from the viewpoint of improving the dispersibility of the inorganic filler (C). More preferably, it is -3 mass%. More preferably, it is 0.1-1 mass%.

  The production method of the acid-modified product (B) of the ethylene-α-olefin copolymer is not particularly limited, but ethylene and α-olefin are anhydrous maleic using a polymerization catalyst containing a metallocene catalyst and an organoaluminum compound as catalyst components. There is a method of copolymerizing in the presence of an unsaturated carboxylic acid-containing compound such as an acid or a derivative thereof. In addition, unsaturated carboxylic acid-containing compounds are obtained by adding radicals generated by organic peroxides or thermal decomposition methods after adding unsaturated carboxylic acid-containing compounds or their derivatives after copolymerization of ethylene and α-olefin. A method of grafting a compound or a derivative thereof to an α-olefin can be exemplified. Examples of the polymerization method include a continuous slurry polymerization method and a continuous bulk polymerization method, and a continuous slurry polymerization method is preferable.

The weight average molecular weight of the acid-modified product (B) of the ethylene-α-olefin copolymer is preferably 70,000 to 500,000, more preferably 100,000 to 200,000. When the weight average molecular weight of the acid-modified product (B) of the ethylene-α-olefin copolymer is 70,000 or more, the following effects are obtained. First, the thermal conductivity, surface smoothness and mechanical properties of the molded body are further improved. Moreover, it is preferable because the moldability becomes better, for example, the resin composition is difficult to draw down during molding. Furthermore, since an appropriate shearing force is easily applied during kneading, the inorganic filler (C) can be appropriately unwound and the molded article can be made smooth.
Moreover, when the weight average molecular weight is less than 500,000, the overload to the kneading machine and the viscosity difference with the material do not become too large, and the dispersion of the inorganic filler (C) becomes easy.

The content (mass) ratio of the acid-modified product (B) of the ethylene-α-olefin copolymer to the polyamide resin (A) is the acid modification of the polyamide resin (A) / ethylene-α-olefin copolymer. Object (B) = 70/30 to 95/5. By being in this range, the effect of improving the dispersibility of the inorganic filler and improving the mechanical properties can be expected. More preferably, it is 80 / 20-90 / 10. By making it in this range, it is expected that the dispersibility of the filler and the mechanical properties are improved by the acid-modified product of the ethylene-α-olefin copolymer while maintaining the heat resistance inherent to the polyamide resin.
That is, in a total of 100% by mass of the polyamide resin (A) and the acid-modified product (B) of the ethylene-α-olefin copolymer, the content of the acid-modified product (B) of the ethylene-α-olefin copolymer is: It is 5-30 mass%, Preferably it is 10-20 mass%.

  In 100% by mass of the whole resin composition, the acid-modified product (B) of the ethylene-α-olefin copolymer is preferably 0.6 to 17% by mass, more preferably 1 to 17% by mass, and still more preferably. Is 2-12% by mass. By being in the range of 0.6 to 17% by mass, the resin composition can be produced without impairing the heat resistance of the resin composition.

<Inorganic filler (C)>
The inorganic filler (C) used in the present embodiment is a particle having an inorganic substance as a core. Therefore, not only the inorganic substance alone, but also the core-shell type particles in which the coating layer covering the core of the inorganic substance is an organic substance (for example, a ligand or a surface treatment agent) is an inorganic filler (C). Moreover, the particle | grains of only a nucleus may be sufficient.

  The inorganic filler refers to inorganic particles such as ceramics and carbon material. Moreover, the heat conductivity is generally preferably 5 W / mK or more. As a single substance having no coating layer on the particle surface of the inorganic filler, examples of the carbon material include graphite, graphene, carbon nanotube, carbon nanohorn, carbon nanofiber, carbon fiber, and fullerene. In ceramics, for example, calcium oxide, calcium carbonate, magnesium oxide, magnesium carbonate, aluminum oxide, boron nitride, aluminum nitride, kaolin clay, aluminum phosphate, magnesium phosphate and other metal oxides, nitrides, borides, carbonates, A phosphate is mentioned. In the case of the inorganic filler (C) of core-shell type particles, a coating layer may be formed thereon.

  When the inorganic filler (C) has a thermal conductivity of 5 W / mK or more, it becomes possible to obtain a resin composition that can be suitably used for removal of heat generation in electrical and electronic equipment having excellent thermal conductivity. . In addition to the core, the inorganic filler (C) having a coating layer preferably has a thermal conductivity of 5 W / mK or more.

Examples of the method for measuring the thermal conductivity of the inorganic filler (C) include a steady method, a hot disk method, a periodic heating method, a hot wire method, and a laser flash method. Any method may be used.
Specifically, as a method for measuring the thermal conductivity of the inorganic filler (C), for example, a hot disk method is used, and measurement is performed in an atmosphere at 23 ° C. using a thermophysical property measuring device TPS-500 and a sensor having a diameter of 7 mmφ. Can be sought.

The average particle size of the inorganic filler (C) is preferably from 0.1 to 50 μm, more preferably from 1 to 30 μm. The average particle diameter can be measured using an electron microscope.
Specifically, for example, using an electron microscope (scanning electron microscope S-4300, manufactured by Hitachi, Ltd.), the maximum value of each particle diameter observed in an enlarged image (approximately 3,000 to 10,000 times) An intermediate value of the minimum values is obtained, and the average value of about 20 to 50 particles is the particle diameter in this embodiment. When the average particle diameter is within the above range, the heat conductive particles themselves are less likely to aggregate, the dispersibility is good and sufficient heat conductivity is obtained, and the molding processability and mechanical properties are improved.

  When the inorganic filler (C) has a coating layer on the particle surface, it is preferable from the viewpoint of improving dispersibility. Examples of the coating layer include an organic treatment formed with a phosphate ester, a silane coupling agent, etc., for example, an inorganic treatment formed with aluminum oxide, silicon oxide, or the like. As the coating layer, organic treatment and inorganic treatment may be used alone or in combination.

Specific examples of the surface treatment agent include methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, butyltrimethoxysilane, and butyltrimethoxysilane. Alkoxyalkoxysilane compounds such as ethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, β Epoxysilane compounds such as-(3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, With aminosilane compounds such as γ- (2-aminoethyl) aminopropyltrimethoxysilane and γ-aminopropyltrimethoxysilane, long chain fatty acids such as stearic acid, oleic acid, montanic acid, stearyl alcohol or long chain aliphatic alcohols Surface treatment may be performed. These surface treatment agents can be used alone or in combination of two or more.
The surface treating agent is preferably an alkylalkoxysilane compound having no reactive functional group other than an alkoxysilyl group. Since there is no reactive functional group other than the alkoxysilyl group, that is, a hydrophilic group, the hydrophobicity of the thermally conductive particles after the surface treatment is increased, and the dispersibility in the polyamide resin is further improved.

  It is preferable that the coating layer formed with the surface treatment agent is 0.05 to 5 parts by mass with respect to 100 parts by mass of the inorganic filler (C). When the coating layer is in the above range, the inorganic filler (C) having the coating layer is further improved in dispersibility with the polyamide resin.

  For the formation of the coating layer in the surface treatment agent of the inorganic filler (C), a direct treatment method (eg, dry method, slurry method, spray method, etc.), an integral blend method (eg, direct method, masterbatch method, etc.), dry A known method such as a concentrate method can be used. Of these, a direct treatment method, particularly a dry method, is preferred as a method that allows simple treatment.

  In the case of performing the dry method, for example, a method of mixing the inorganic filler with stirring or mixing with a Henschel mixer or the like while dripping or spraying the surface treatment agent, and heat-treating as necessary can be mentioned. Since the heat conductive particles after the formation of the coating layer may aggregate, it is preferable to grind with a ball mill or the like. It is also preferable to form the coating layer after diluting with an organic solvent such as alcohol when the surface treatment agent is dropped or sprayed.

<Antioxidant>
The antioxidant used in the present embodiment can suppress thermal degradation of the polyamide resin (A) during the production of the resin composition and the molded body. As the antioxidant, a known compound can be used. Examples of the antioxidant include phenol-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, lactone-based antioxidants, amine-based antioxidants, and amide-based antioxidants. Antioxidants can be used alone or in combination of two or more.

  The antioxidant may be used as long as dispersion failure does not occur. For example, the antioxidant is preferably contained in an amount of 0.01 to 5% by mass, more preferably 0.1 to 3% by mass in 100% by mass of the resin composition. .

<Other optional components>
The resin composition of this embodiment can mix | blend another arbitrary component as needed. Examples of other optional components include colorants, antistatic agents, plasticizers, lubricants, antifoaming agents, mold release agents, and flame retardants. The selection of other optional components and the amount of use thereof are not particularly limited as long as they are within the range in which the problem of the present embodiment can be solved.

  As the colorant, known dyes, organic pigments and inorganic pigments can be used. Examples of the dye include styryl dyes, pyridone azo dyes, pyrazole azo dyes, anthraquinone dyes, heteroazo dyes, benzene azo dyes, naphthoquinone dyes, indoaniline dyes, and cyanine dyes according to structural classification. Moreover, according to a use classification, a disperse dye, a vat dye, an oil-soluble dye, etc. are mentioned.

  The organic pigment is, for example, an azo pigment of azo lake, hansa, benzimidazolone, diarylide, pyrazolone, benzidine yellow, disazo; a condensed polycyclic pigment such as phthalocyanine, quinacridone, perylene, perinone, dioxazine, anthraquinone, isoindolinone, and the like Aniline black is mentioned.

<Method for producing resin composition>
In the resin composition of this embodiment, for example, a polyamide resin (A), an acid-modified product (B) of an ethylene-α-olefin copolymer, and an inorganic filler (C) are charged into a processing machine and melt kneaded. Can be manufactured. The melt kneading temperature is preferably 200 to 300 ° C. Processing machines include batch kneaders such as kneaders, roll mills, super mixers, Henschel mixers, Shugi mixers, vertical granulators, high speed mixers, fur matrices, ball mills, steel mills, sand mills, vibration mills, attritors, and banbury mixers. A twin screw extruder, a single screw extruder, a rotor type twin screw kneader, and the like. The shape of the resin composition is preferably, for example, a pellet shape, a powder shape, or a granular shape, and among these, a pellet shape is more preferable.

  40-80 mass% is preferable in 100 mass% of resin compositions, and, as for the ratio of the inorganic filler (C) which the resin composition of this embodiment contains, 60-70 mass% is more preferable. Thermal conductivity improves more by containing 40 mass% or more of inorganic fillers (C). Further, by containing 80% by mass or less of the inorganic filler (C), the moldability and mechanical properties are further improved.

  The molded product of this embodiment can be obtained by melting and kneading the resin composition and using a molding machine. A known method can be used as the molding method. Examples include extrusion molding, injection molding, blow molding, press molding, calendar molding, T-die molding, inflation molding, compression molding, pipe extrusion molding, laminate molding, and vacuum molding. Among these, extrusion molding and injection molding in which a melt is discharged at high speed are preferable, and injection molding is most preferable.

  The molded product of the present embodiment includes, for example, containers and packaging materials [containers and packaging materials for food products (fresh food products, processed food products, soft drinks, etc.), miscellaneous goods (tableware, toys, stationery, electric parts, household appliances, Containers and packaging materials for furniture, luxury goods, etc., textile products (clothing, shoes, bedding, carpets, mats, dust paper, newspapers, handkerchiefs, towels, etc.) containers and packaging materials, chemicals (industrial chemicals, pharmaceuticals, etc.) Containers and packaging materials, various industrial coating materials (agricultural greenhouse house coating materials, automotive surface protection coating sheets, etc.), other uses (plastic bags, shopping bags, garbage bags, etc.) containers and packaging materials], automotive Components [Instrument materials such as instrument panels, door trims, pillars, exterior materials such as bumpers, internal parts such as gasoline tanks, valves, etc.] Home appliances [TVs, video recorders (videos, hard disks, DVDs) BD, etc.), tuner, satellite dish, iron, hair dryer, shaver, electric toothbrush, hair iron, face care equipment, health meter, futon dryer, washing machine, refrigerator, wine cellar, rice cooker, microwave oven, electronic balance, Tableware dryer, food processor, hot plate, electric kettle, coffee maker, IH cooker, garbage disposal machine, vacuum cleaner, clock, telephone, lighting equipment, ventilation fan, air conditioner, fan, hot air heater, dehumidifier, humidifier , Air purifiers, negative ion generators, massage chairs, foot massagers, health appliances, power tools, home game consoles and game software, acoustic components, video cameras, audio equipment, electronic instruments, remote controls, chargers, etc.] Cases and internal parts, etc. PC equipment [PC body, display (CRT, liquid crystal, plasma, projector, organic EL, etc.), notebook computer, printer, recording medium drive (hard disk, MO, memory card, CD, DVD, BD, flexible disk, etc.), recording medium (USB memory, IC card, etc.) ) Housing, housings and internal parts such as mice], small mobile devices [radio devices, mobile phones, PHS, PDA, smartphones, portable game consoles and game software, TVs, navigation devices, GPS, etc. Equipment, headphone stereos, optical cameras, digital cameras, electronic dictionaries and computer casings and internal parts, etc.] and office equipment [copying, facsimiles, scanners and their combined machines, shredders, paper folding, etc.] Machine, electronic blackboard, time clock, net Cases and internal parts of work cameras, smoking counters, label writers, electronic registers, electronic checkwriters, laminators, bookbinding machines, etc.], and cases and internal parts of gaming machines [arcade game machines, pachinko machines, slot machines, etc.] Medical equipment [dry imagers, medical printers, medical recorders, medical cameras, X-ray television systems, CT scanner systems, mammography systems, angiography systems, ultrasonic diagnostic systems, etc. and internal components], electronic components [Various cases, holders, covers, cooling fans, gears, sensors, valves, connectors, sockets, transformer bobbins, resistors, buttons, switches, handles, distribution boards, breakers, capacitors, outlets, motors, transformers , Tuners, electromagnetic switches, optical pickups, oscillators, terminal boards, transformers, plugs, timers, printed wiring boards, etc.], transport materials [containers, flexible containers, carts, trays, carrier tapes, pallets, sheet skids (automobiles) Sheet conveyance), stretch film (for preventing collapse of cargo), cable ties, foam cushioning material, air cap (cushioning material), etc.], molded products for living materials [furniture (chairs, desks, hangers, etc.), building materials such as houses (Various doors such as entrances and interiors, interior / exterior wall materials, ceiling materials, roofing materials, tiles, heat insulation / heat shield materials, etc.), hobby goods [sports equipment (racquets, skis, snowboards, etc.), gardening equipment (planters, etc.) ), Outdoor equipment (fishing rods, etc.)], and other daily goods [tableware, toys, stationery, oral care products, toiletries (bath unit) , Toilet, etc.), it can be used in applications such as health equipment, etc.].

  Among these, it can be suitably used for molded products such as home appliances, OA equipment parts, AV equipment parts, automobile interior and exterior parts, and the like. Particularly in household electrical appliances and OA devices that generate a lot of heat, heat generated in the heat generating part is efficiently transmitted to the heat radiating part. Heat dissipation sheet to dissipate heat effectively, and also use as an exterior material to dissipate the heat generated internally in electronic equipment that has a heat source inside but is difficult to forcibly cool with a fan etc. Can do. For this reason, portable computers such as notebook computers, PDAs, mobile phones, portable game machines, portable music players, portable TV / video devices, small or portable electronic devices such as portable video cameras, LED lamps and batteries It is suitable for a heat conducting member used for a component that requires high heat dissipation around a heat source such as a surrounding component. In addition, although the resin composition which concerns on this embodiment is excellent in heat conductivity, it cannot be overemphasized that you may use as a resin composition and a molded object which are not required for heat conductivity.

  According to the resin composition of this embodiment, a resin composition excellent in thermal conductivity, mechanical properties, surface smoothness and recyclability can be obtained. Moreover, according to the resin composition of the present embodiment, the inorganic filler (C) is blended by blending a specific amount of the polyamide resin (A) and the acid-modified product (B) of the ethylene-α-olefin copolymer. Dispersibility is improved, and a resin composition rich in surface smoothness and thermal conductivity of the molded product is obtained. Moreover, since a softening agent is not used when blending a large amount of the inorganic filler (C), a resin composition rich in heat resistance and mechanical properties can be obtained.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example. In the examples, “part” means “part by mass”, and “%” means “% by mass”.

The measuring method of the weight average molecular weight of the acid-modified product (B) of the ethylene-α-olefin copolymer and the measuring method of the thermal conductivity of the inorganic filler (C) are as follows.
<Weight average molecular weight of acid-modified product of ethylene-α-olefin copolymer>
Using a Prominence GPC system manufactured by Shimadzu Corporation, a molecular weight distribution curve was measured by a gel permeation chromatograph (GPC) method, and a weight average molecular weight (Mw) and a number average molecular weight (Mn) were calculated from values in terms of polystyrene. The molecular weight distribution (Mw / Mn) was calculated from the obtained weight average molecular weight and number average molecular weight values. As standard polystyrene used for polystyrene conversion, polystyrene manufactured by VARIAN was used, TSKgelGMH-HT manufactured by Tosoh Corporation was used as a column, and orthodichlorobenzene was used as a carrier at the time of measurement. The column temperature was 140 ° C. and the carrier flow rate was 1.0 mL.

<Measuring method of thermal conductivity of inorganic filler (C)>
A plate-like sample in which the inorganic filler (C) was compressed at 100 MPa was prepared using a press. The sample was measured in an atmosphere of 23 ° C. using a hot disk method thermophysical property measuring apparatus TPS-500 manufactured by Kyoto Electronics Industry Co., Ltd. and a sensor having a diameter of 7 mmφ.

  The raw material components of the compositions used in the following examples and comparative examples are shown.

<Polyamide resin (A)>
A-1: Polyamide 6 (density 1.13 g / cm ³ , melting point 225 ° C.)
A-2: Polyamide 66 (density 1.20 g / cm ³ , melting point 265 ° C.)

<Acid modified product of ethylene-α-olefin copolymer (B)>
B-1: Maleic anhydride-modified product of ethylene-octene copolymer (Mw = 1 × 10 ⁵ )
B-2: A modified maleic anhydride of an ethylene-octene copolymer (Mw = 3 × 10 ⁵ )
B-3: Maleic anhydride-modified product of ethylene-octene copolymer (Mw = 2 × 10 ⁵ )
B-4: Maleic anhydride-modified product of ethylene-octene copolymer (Mw = 4 × 10 ⁴ )
B-5: A modified maleic anhydride of an ethylene-octene copolymer (Mw = 8 × 10 ⁴ )
B-6: Maleic anhydride modified product of ethylene-butene copolymer (Mw = 2 × 10 ⁵ )
B-7: Adipic acid modified product of ethylene-butene copolymer (Mw = 2 × 10 ⁵ )
B-8: Maleic anhydride modified product of ethylene-butene copolymer (Mw = 1 × 10 ⁵ )
B-9: Adipic acid modified product of ethylene-butene copolymer (Mw = 1 × 10 ⁵ )
B-10: Maleic anhydride modified product of ethylene-hexene copolymer (Mw = 2 × 10 ⁵ )
B-11: Adipic acid modified product of ethylene-hexene copolymer (Mw = 2 × 10 ⁵ )
B-12: Maleic anhydride-modified product of ethylene-hexene copolymer (Mw = 1 × 10 ⁵ )
B-13: Adipic acid-modified product of ethylene-hexene copolymer (Mw = 1 × 10 ⁵ )
B-14: Maleic anhydride-modified product of ethylene-4 methylpentene copolymer (Mw = 2 × 10 ⁵ )
B-15: Maleic anhydride-modified product of ethylene-4 methylpentene copolymer (Mw = 2 × 10 ⁵ )
B-16: Maleic anhydride-modified product of ethylene-4 methylpentene copolymer (Mw = 1 × 10 ⁵ )
B-17: Maleic anhydride modified product of ethylene-4methylpentene copolymer (Mw = 1 × 10 ⁵ )

<Synthesis of acid-modified product (B-1) of ethylene-α-olefin copolymer>
In a 1000 mL flask equipped with a condenser, 400 mL of xylene as a solvent, 60 g of an ethylene-octene copolymer (Prime Polymer Co., Moatech 0138N) as a base resin (X) (hereinafter also referred to simply as (X)), unsaturated After adding 1.0 g of maleic anhydride as a carboxylic acid and its derivative (Y) (hereinafter also simply referred to as (Y)), heating and stirring at 140 ° C. to dissolve the ethylene-octene copolymer, 40 mL of xylene A xylene solution in which 4.0 g of dicumyl peroxide was dissolved was added dropwise over 1 hour. After completion of the dropwise addition, the reaction was continued at 140 ° C. for 6 hours. An oil bath was used for heating. After completion of the reaction, the content was lowered to room temperature and poured into acetone to precipitate the target ethylene-α-olefin copolymer acid-modified product, followed by filtration.
In order to remove unreacted maleic anhydride from the acid-modified product of the obtained ethylene-α-olefin copolymer, it was put into 500 mL of methyl ethyl ketone, stirred for 10 minutes, and then filtered. This operation was repeated twice, followed by vacuum drying at 120 ° C. and 10 mmHg or less for 2 hours to obtain an acid-modified product (B-1) of an ethylene-α-olefin copolymer.

<Synthesis of (B-2 to B-5)>
For the synthesis of (B-1), B-2 to B-5 were obtained by changing the amount of maleic anhydride (Y) and the reaction temperature.
<Synthesis of (B-6 to B-9)>
For the synthesis of (B-1), an ethylene-butene copolymer (manufactured by Prime Polymer, Neozex 20201J) is used as (X), and the amount of maleic anhydride or adipic acid and the reaction temperature are changed as (Y). As a result, B-6 to B-9 were obtained.
<Synthesis of (B-10 to B-13)>
For the synthesis of (B-1), an ethylene-hexene copolymer (Prime Polymer, Evolue SP3010) is used as (X), and the amount of maleic anhydride or adipic acid and the reaction temperature are changed as (Y). As a result, B-10 to B-13 were obtained.
<Synthesis of (B-14 to B-17)>
For the synthesis of (B-1), ethylene- 4 methylpentene copolymer (manufactured by Prime Polymer Co., Ltd., Ultzex 2022N) is used as (X), and amount of maleic anhydride or adipic acid and reaction temperature as (Y) Were changed to obtain B-14 to B-17.

<Inorganic filler (C)>
Inorganic filler (C-1); average particle size: 1 μm, thermal conductivity 15 W / mK
Inorganic filler (C-2); average particle size: 20 μm, thermal conductivity 15 W / mK
Inorganic filler (C-3); average particle size: 50 μm, thermal conductivity 15 W / mK
Inorganic filler (C-4); average particle size: 13 μm, thermal conductivity 35 W / mK
Inorganic filler (C-5); average particle size: 1 μm, thermal conductivity 15 W / mK
Inorganic filler (C-6); average particle size: 1 μm, thermal conductivity 15 W / mK
Inorganic filler (C-7); synthetic anhydrous magnesium carbonate average particle size: 1 μm, thermal conductivity 15 W / mK

<Method for producing inorganic filler (C-1)>
Add n-dodecyltrimethoxysilane to synthetic anhydrous magnesium carbonate with an average particle size of 1 μm so that the synthetic anhydrous magnesium carbonate is 99 mass% and n-dodecyltrimethoxysilane is 1 mass%, and the speed is 30 Hz with a Henschel shell mixer. The mixture was stirred for 10 minutes while heating to 80 ° C. to obtain an inorganic filler (C-1).

<Method for producing inorganic filler (C-2)>
Inorganic filler (C-2) was prepared in the same manner as inorganic filler (C-1) except that synthetic anhydrous magnesium carbonate having an average particle diameter of 20 μm was used instead of synthetic anhydrous magnesium carbonate having an average particle diameter of 1 μm. Got.

<Method for producing inorganic filler (C-3)>
An inorganic filler (C-3) was prepared in the same manner as the inorganic filler (C-1) except that synthetic anhydrous magnesium carbonate having an average particle diameter of 50 μm was used instead of the synthetic anhydrous magnesium carbonate having an average particle diameter of 1 μm. Got.

<Method for producing inorganic filler (C-4)>
N-dodecyltrimethoxysilane was added to boron nitride (MGP, manufactured by Denki Kagaku Kogyo Co., Ltd.) with an average particle size of 13 μm so that boron nitride would be 97% by mass and n-dodecyltrimethoxysilane would be 3% by mass, and Henschel shell It stirred for 10 minutes, heating at 80 degreeC with the speed | rate of 30 Hz with the mixer, and obtained the inorganic filler (C-4).

<Method for producing inorganic filler (C-5)>
Aminotrimethoxysilane is added to synthetic anhydrous magnesium carbonate having an average particle size of 1 μm so that the synthetic anhydrous magnesium carbonate is 99% by mass and the aminotrimethoxysilane is 1% by mass, and the temperature is increased to 80 ° C. at 30 Hz with a Henschel shell mixer. It stirred for 10 minutes, heating, and obtained the inorganic filler (C-5).

<Method for producing inorganic filler (C-6)>
An inorganic filler (C-6) was obtained in the same manner as the method for producing the inorganic filler (C-5) except that epoxytrimethoxysilane was used instead of aminotrimethoxysilane.

<Thermoplastic resin>
Thermoplastic resin (1): ethylene-α-olefin copolymer (manufactured by Nippon Polyethylene Co., Ltd., Kernel KF283, Mw = 7 × 10 ⁴ )

[Example 1]
[Production of resin composition]
A Henschel mixer was charged with 38% by mass of polyamide resin (A-1), 2% by mass of an acid-modified product of ethylene-α-olefin copolymer (B-1) and 60% by mass of an inorganic filler (C-1). And premixed at a temperature of 20 ° C. for 3 minutes, and then supplied to an extruder having a screw diameter of 30 mm and L / D (screw diameter / screw length) = 38 to 42, with a rotational speed of 250 rpm and a set temperature of 250 A pellet-shaped resin composition was obtained using a pelletizer after melt-kneading and extruding under the condition of ° C.

[Examples 2-37, Comparative Examples 1-6]
A pellet-shaped resin composition was obtained in the same manner as the resin composition of Example 1 except that the types of materials described in Tables 1, 2, and 3 and the blending amount (mass%) were used.

〔Evaluation method〕
The following evaluation items were tested using the resin compositions obtained by blending Tables 1 to 3. The results are shown in Table 4.

<Thermal conductivity>
The resin composition was put into an injection molding machine (manufactured by Toshiba Machine Co., Ltd.) and heated to 250 ° C., and 6 plates of vertical and horizontal 50 mm and thickness 2 mm were prepared at an injection pressure of 50 MPa and a mold temperature of 40 ° C. The thermal conductivity (unit: W / m · K) was measured using a hot disk method thermophysical property measuring apparatus (TPS-500, manufactured by Kyoto Electronics Industry Co., Ltd.) using a sensor having a diameter of 7 mmφ.

<Measurement of tensile fracture strength>
The resin composition was put into an injection molding machine (manufactured by Toshiba Machine Co., Ltd.), and a dumbbell test piece (JIS K 7139, type A1, thickness 4 mm) was produced at an injection pressure of 50 MPa and a mold temperature of 40 ° C. The test piece was subjected to tensile fracture strength measurement according to JIS K 7161 using Strograph VE10D (manufactured by Toyo Seiki Co., Ltd.). The lower the value of the tensile strength at break, the lower the mechanical strength of the specimen. When producing a resin composition, if the thermoplastic resin contains many foreign substances due to deterioration due to oxidation and hydrolysis, deposits or generation of eyes, the tensile fracture point strength decreases.

<Skin layer evaluation>
The resin composition is put into an injection molding machine (manufactured by TOSHIBA MACHINERY CO., LTD.), An injection temperature of 250 ° C., an injection pressure of 50 MPa, a mold temperature of 40 ° C., and a plate having a length and width of 50 mm and a thickness of 2 mm. A shaped molded product was produced. The obtained molded product was cut, and the surface of the skin layer was observed at a magnification of 1000 times using a video microscope “VHX-900” (manufactured by Keyence Corporation). A thinner skin layer does not hinder heat conduction, and a molded article having high heat conductivity can be obtained.
A: The thickness of the skin layer is less than 3 μm.
B: The thickness of the skin layer is 3 μm or more.

<Surface smoothness>
A thermally conductive resin composition is put into a T-die film molding machine (manufactured by Toyo Seiki Co., Ltd.), melted at a molding temperature of 250 ° C. and a screw rotation speed of 80 rpm, and extruded to form a film having a width of 100 mm and a thickness of 100 μm. The molded product was obtained. About the obtained film 1m, surface smoothness evaluation by visual observation was performed. It was evaluated whether or not aggregates exist as protrusions on the film surface.
A: There is no protrusion and it is smooth.
B: 1 to 10 protrusions or no protrusions but not smooth.
C: 11 or more protrusions exist.

As is apparent from Table 4, it was confirmed that the use of the thermally conductive resin composition of the present example yielded a molded article having good thermal conductivity and molding processability and good mechanical strength. . Thus, the heat conductive resin composition of the present Example is excellent in moldability even when the inorganic filler (C) is blended at a high concentration.
On the other hand, in the molded product using the heat conductive resin composition of the comparative example, the thermal conductivity, smoothness, and mechanical strength were significantly reduced, which was inferior to the molded product of this example.

Claims (7)

Polyamide resin (A),
A resin composition containing an acid-modified product (B) of an ethylene-α-olefin copolymer containing a structural unit derived from ethylene and a structural unit derived from an α-olefin having 6 to 20 carbon atoms and an inorganic filler (C). Yes,
The content ratio of the polyamide resin (A) and the acid-modified product (B) of ethylene-α-olefin copolymer is polyamide resin (A) / acid-modified product of ethylene-α-olefin copolymer (B) = 70. / 30 to 95/5,
Of the total 100% by mass of the resin composition, the polyamide resin (A) is 10 to 40% by mass, the acid-modified product (B) of the ethylene-α-olefin copolymer is 0.6 to 17% by mass, and the inorganic filler ( C) is 40-80% by weight,
However, the case where the acid-modified product (B) of the ethylene-α-olefin copolymer is a maleic anhydride-modified product of ethylene-octene copolymer and the inorganic filler (C) is inorganic particles is excluded. ,
Thermally conductive resin composition.   The thermally conductive resin composition according to claim 1, wherein the inorganic filler (C) is a particle that may have a coating layer.   The heat conductive resin composition of Claim 1 or 2 whose average particle diameter of an inorganic filler (C) is 0.1-50 micrometers.   The heat conductive resin composition in any one of Claims 1-3 whose weight average molecular weights of the acid modification material (B) of an ethylene-alpha-olefin copolymer are 70,000-500,000.   The thermal conductivity of the inorganic filler (C) is 5 W / mK or more, and the thermally conductive resin composition according to any one of claims 1 to 4.   The molded object formed by shape | molding the heat conductive resin composition in any one of Claims 1-5.   The molded object of Claim 6 whose heat conductivity measured by the hot disk method is 1.1 W / mK or more.