JP2021181541A - Heat-conductive resin composition, and compact comprising the same - Google Patents

Abstract

To provide a resin composition capable of manufacturing a compact excellent in fog resistance, while heat conductivity in a flow direction is 2 W/(m-K) or greater.SOLUTION: A heat-conductive resin composition contains a thermoplastic resin (A) and a heat-conductive filler (B). In the heat-conductive resin composition, a mass ratio between the thermoplastic resin (A) and the heat-conductive filler (B) is 38/62 to 85/15, a haze value of a glass sheet after a fogging test of 200 hours at 125°C is 8 or lower, and heat conductivity in a flow direction of a compact obtained by molding the heat-conductive resin composition is 2 W/(m-K) or greater.SELECTED DRAWING: None

Description

INDUSTRIAL APPLICABILITY The present invention contains a thermoplastic resin and a thermally conductive filler, and can produce a molded body having excellent fogging resistance and a thermal conductivity of 2 W / (m · K) or more in the flow direction. It relates to a resin composition and a molded body made of the resin composition.

In recent years, the amount of heat generated has increased due to the higher performance of parts and products, but the heat dissipation space has decreased as the parts and products have become smaller and lighter. Therefore, measures against heat that effectively dissipate the generated heat to the outside have become a very important issue, and there are increasing calls for improving the heat dissipation of the resin molding material (for example, resin composition) that is the constituent material. It's coming. For example, it is necessary to efficiently dissipate heat from an LED in order to extend its life, and it is also important that the lens does not fog when the lamp is lit for a long time. Therefore, good fogging resistance of the members used is also required. Considering the amount of heat radiation that leads to a longer life of the LED, the thermal conductivity in the flow direction is 2 W / (m), which is 10 times the thermal conductivity of 0.2 W / (m · K) of a general resin composition.・ K) is required. Therefore, there is a demand for a material having a thermal conductivity of 2 W / (m · K) or more in the flow direction of the molded product and having good fogging resistance.

It has been known that a resin composition having high thermal conductivity can be obtained by highly filling a resin material with a thermally conductive filler (for example, graphite, copper, aluminum, aluminum oxide, etc.) having high thermal conductivity. Has been done. Molds manufactured using such a resin composition have been studied as members for manufacturing electrical and electronic parts (for example, Patent Documents 1 to 4).

On the other hand, in the field of thermally conductive resin compositions, it is also required to be able to produce a molded body having excellent mechanical strength such as bending strength and flexural modulus with good fluidity.

Japanese Unexamined Patent Publication No. 62-100577 Japanese Unexamined Patent Publication No. 4-178421 Japanese Unexamined Patent Publication No. 5-86246 Japanese Unexamined Patent Publication No. 2011-116842

When the inventor of the present invention manufactures a resin composition containing a large amount of a heat conductive filler by a conventional manufacturing method, the degassing during manufacturing becomes insufficient, and the resin composition can be obtained by using the resin composition. It has been found that there arises a problem that the fogging resistance of the molded product is deteriorated. Specifically, the degassing in the production of the resin composition is performed by simply evacuating from the vent port provided in the vicinity of the most downstream in the extrusion direction in the extruder in the conventional method. At this time, if a large amount of the heat conductive filler is blended in the resin composition, the internal pressure becomes high, and the melt tends to overflow from the vent port and / or the vent port tends to be closed. , I couldn't do enough degassing. Therefore, it is considered that the residual monomer component in the thermoplastic resin, the decomposition product component due to heat, and the like cannot be sufficiently removed from the resin composition, and the fogging resistance of the molded product deteriorates.

The present invention provides a resin composition capable of producing a molded body having excellent fogging resistance while having a thermal conductivity of 2 W / (m · K) or more in the flow direction, and a molded body obtained from the resin composition. The purpose is.

The present invention also relates to a resin composition capable of producing a molded product having excellent fogging resistance, bending characteristics and molding fluidity while having a thermal conductivity of 2 W / (m · K) or more in the flow direction. It is an object of the present invention to provide a more obtained molded product.

In the present specification, the thermal conductivity is a property in which heat is easily conducted in a molded product manufactured by using the thermally conductive resin composition. The thermal conductivity may be, for example, a characteristic that the thermal conductivity in the flow direction at the time of manufacturing a molded body (for example, at the time of injection molding) is 2 W / (m · K) or more.
The fogging resistance is a property that the molded product manufactured by using the heat conductive resin composition is less likely to be fogged even in a high temperature environment of 100 ° C. or higher (for example, 125 ° C.).
The bending property is a property in which the bending strength and the bending elastic modulus of the molded product manufactured by using the heat conductive resin composition are sufficiently high.
Molding fluidity is a characteristic that the resin composition can sufficiently flow when a molded product is produced using the thermally conductive resin composition.

Thermal conductivity and fogging resistance are the characteristics of the thermally conductive resin composition of the present invention.
Bending characteristics and molding fluidity are not the characteristics that the thermally conductive resin composition of the present invention must have, but the characteristics that the thermally conductive resin composition of the present invention usually has or are preferable to have. Is.

As a result of diligent research to solve the above-mentioned problems, the present inventors have solved the above-mentioned problems by strengthening the degassing by the vacuum pump when compounding the thermoplastic resin and the heat conductive filler. We found that and arrived at the present invention.

The gist of the present invention is as follows.
<1> A thermally conductive resin composition containing a thermoplastic resin (A) and a thermally conductive filler (B).
The mass ratio of the thermoplastic resin (A) to the thermally conductive filler (B) is 38/62 to 85/15.
The haze value of the glass plate after the fogging test at 125 ° C. for 200 hours is 8 or less.
A heat conductive resin composition having a heat conductivity of 2 W / (m · K) or more in the flow direction of a molded body obtained by molding the heat conductive resin composition.
<2> The thermally conductive filler (B) is talc, aluminum oxide, magnesium oxide, zinc oxide, magnesium carbonate, silicon carbide, aluminum nitride, boron nitride, silicon nitride, carbon, graphite, silver, copper, aluminum, The thermally conductive resin composition according to <1>, which is one or more materials selected from the group consisting of titanium, nickel, tin, iron, and stainless steel.
<3> The thermally conductive resin composition further contains a non-thermally conductive fibrous reinforcing material (C), and the total of the thermoplastic resin (A) and the thermally conductive filler (B) and the non-thermally conductive filler. The heat conductive resin composition according to <1> or <2>, wherein the mass ratio with the heat conductive fibrous reinforcing material (C) is 100/0 to 50/50.
<4> The thermally conductive resin composition according to <3>, wherein the non-thermally conductive fibrous reinforcing material (C) is glass fiber.
<5> The thermally conductive resin composition according to any one of <1> to <4>, wherein the thermoplastic resin (A) is a polyamide.
<6> The thermoplastic resin (A) is composed of a crystalline polyamide and an amorphous polyamide, and the mass ratio of the crystalline polyamide to the amorphous polyamide is 100/0 to 40/60. 1> The thermally conductive resin composition according to any one of <5>.
<7> The mass ratio of the thermoplastic resin (A) to the thermally conductive filler (B) is 38/62 to 75/25.
The heat conductive resin composition according to any one of <1> to <6>, wherein the heat conductive filler (B) is graphite.
<8> The mass ratio of the thermoplastic resin (A) to the thermally conductive filler (B) is 45/55 to 70/30.
The thermally conductive filler (B) is scaly graphite having an average particle size of 80 to 180 μm.
The thermally conductive resin composition further contains a non-thermally conductive fibrous reinforcing material (C).
The mass ratio of the total of the thermoplastic resin (A) and the thermally conductive filler (B) to the non-thermally conductive fibrous reinforcing material (C) is 100/0 to 75/25, <1>. The thermally conductive resin composition according to any one of ~ <7>.
<9> A molded product made of the thermally conductive resin composition according to any one of <1> to <8>.

According to the present invention, a resin composition capable of producing a molded body having excellent fogging resistance while having a thermal conductivity of 2 W / (m · K) or more in the flow direction and a molded body obtained by the resin composition can be produced. Can be provided.

A schematic cross-sectional view of an extruder for producing the resin composition of the present invention is shown. The schematic diagram for demonstrating the method of measuring the haze value which defines the resin composition of this invention is shown. The schematic diagram of the air collecting bottle used in the method of measuring the haze value which defines the resin composition of this invention is shown.

[Thermal conductive resin composition]
The thermally conductive resin composition of the present invention contains a thermoplastic resin (A) and a thermally conductive filler (B).

The thermoplastic resin (A) used in the present invention is not particularly limited, but is, for example, an olefin resin such as polyethylene, polypropylene, an ethylene-α-olefin copolymer (for example, an ethylene-propylene copolymer, etc.); polymethylpentene. Polyvinyl chloride; Polyvinylidene chloride; Polyvinyl acetate; Ethylene-vinyl acetate copolymer; Polyvinyl alcohol; Polyvinylacetal; Fluororesin such as polyvinylidene fluoride, polytetrafluoroethylene; Polyethylene terephthalate, Polybutylene terephthalate, Polyethylene naphthalate , Polylactic acid and other polyester resins; polystyrene; polyacrylonitrile; styrene-acrylonitrile copolymer; ABS resin; polyphenylene ether (PPE); modified PPE; polyimide; polyamide, polyamideimide and other amide bond-containing polymers; polyetherimide; poly Examples thereof include polymethacrylic acid esters such as methyl methacrylate; polyacrylic acid; polycarbonate; polyarylate; polyphenylene sulfide; polysulfone; polyether sulfone; polyether nitrile; polyether ketone; polyketone; liquid crystal polymer. Among them, an amide bond-containing polymer, particularly a polyamide resin, is preferable because it has excellent molding processability and easily develops thermal conductivity when the thermally conductive filler (B) is blended.

The polyamide resin used in the present invention is a homopolyamide or copolyamide having an amide bond, or a mixture thereof. Homopolyamides and copolyamides having an amide bond can be obtained by polymerizing lactam, aminocarboxylic acid, diamine, dicarboxylic acid and the like. Examples of the lactam, aminocarboxylic acid and diamine, and dicarboxylic acid constituting the homopolyamide and copolyamide include lactam, aminocarboxylic acid, diamine and dicarboxylic acid which can form the crystalline polyamide and the amorphous polyamide described later, respectively. ..

The crystalline (or amorphous) of the polyamide resin is not particularly limited, and the polyamide resin is, for example, crystalline polyamide (A-1-1) alone or crystalline polyamide (A-1-1) and amorphous polyamide. It may be any mixture of (A-1-2).

The crystalline polyamide (A-1-1) has a value of heat of fusion measured at a heating rate of 16 ° C./min under a nitrogen atmosphere using a differential scanning calorimeter (DSC) of 1 cal / g or more. Means polyamide resin.
Amorphous polyamide (A-1-2) has a melting heat value of less than 1 cal / g measured at a heating rate of 16 ° C./min under a nitrogen atmosphere using a differential scanning calorimeter (DSC). It means a certain polyamide resin.

Examples of the crystalline polyamide (A-1-1) include polytetramethylene isophthalamide (polyamide 4I), polytetramethylene terephthalamide (polyamide 4T), polycapramide (polyamide 6), and polytetramethylene adipamide (polypolyzone 46). ), Polyhexamethylene adipamide (polyamide 66), polycapramide / polyhexamethylene adipamide copolymer (polyamide 6/66), polyundecamide (polyamide 11), polycapramide / polyundecamide copolymer (polyamide 6/11), polydodecamide. (Polyamide 12), polycoupled / polydodecamide copolymer (polyamide 6/12), polyhexamethylene sebacamide (polyamide 610), polyhexamethylene dodecamide (polyamide 612), polyundecamethylene adipamide (polyamide 116). , Polyhexamethylene isophthalamide (Polyamide 6I), Polyhexamethylene terephthalamide (Polyamide 6T), Polycapramide / Polytetramethylene terephthalamide copolymer (Polyamide 6 / 4T), Polycapramido / Polytetramethylene isophthalamide copolymer (Polyamide 6 / 4I) , Polyhexamethylene adipamide / polytetramethylene terephthalamide copolymer (polyamide 66 / 4T), polyhexamethylene adipamide / polytetramethylene isophthalamide copolymer (polyoxide 66 / 4I), polyhexamethylene terephthalamide / polyhexamethylene Isophthalamide copolymer (polyamide 6T / 6I), polycapramide / polyhexamethylene terephthalamide copolymer (polyamide 6 / 6T), polycapramide / polyhexamethylene isophthalamide copolymer (polyamide 6/6I), polyhexamethylene adipamide / polyhexamethylene Telephthalamide copolymer (polyamide 66 / 6T), polyhexamethylene adipamide / polyhexamethylene isophthalamide copolymer (polyamide 66 / 6I), polytrimethylhexamethylene terephthalamide (polyamide TMDT), polybis (4-aminocyclohexyl) methandodeca Mid (polyamide PACM12), polybis (3-methyl-4-aminocyclohexyl) methadodecamide (polyamide dimethyl PACM12), polymethoxylylene adipamide (polyamide MXD6), polyoctamethylene terephthalamide (polyoxide PACM12) Polyamide 8T), polynonamethylene terephthalamide (polyamide 9T), polydecamethylene terephthalamide (polyamide 10T), polyundecamethylene terephthalamide (polyamide 11T) and mixtures thereof. Of these, polyamide 6 and / or polyamide 66 is more preferred from the viewpoint of further improving thermal conductivity and fogging resistance, as well as improving bending properties and molding fluidity. As the crystalline polyamide resin, one of the above may be used alone or in combination.

Examples of the amorphous polyamide (A-1-2) include isophthalic acid / terephthalic acid / 1,6-hexanediamine / bis (3-methyl-4-aminocyclohexyl) methane copolymer and terephthalic acid / 2, 2,4-trimethyl-1,6-hexanediamine / 2,4,4-trimethyl-1,6-hexanediamine copolymer, isophthalic acid / bis (3-methyl-4-aminocyclohexyl) methane / ω-lauro Lactum copolymer, isophthalic acid / terephthalic acid / 1,6-hexanediamine copolymer, isophthalic acid / 2,2,4-trimethyl-1,6-hexanediamine / 2,4,4-trimethyl-1,6 -Hexanediamine copolymer, isophthalic acid / terephthalic acid / 2,2,4-trimethyl-1,6-hexanediamine / 2,4,4-trimethyl-1,6-hexanediamine copolymer, isophthalic acid / bis Examples thereof include (3-methyl-4-aminocyclohexyl) methane / ω-laurolactum copolymers and copolymers of isophthalic acid / terephthalic acid / other diamine components. Among them, isophthalic acid / terephthalic acid / 1,6-hexanediamine / bis (3-methyl-4-aminocyclohexyl) methane from the viewpoint of further improvement of thermal conductivity and fogging resistance, and improvement of bending characteristics and molding fluidity. Polymer, terephthalic acid / 2,2,4-trimethyl-1,6-hexanediamine / 2,4,4-trimethyl-1,6-hexanediamine copolymer, isophthalic acid / terephthalic acid / 1,6- Hexadiamine / bis (3-methyl-4-aminocyclohexyl) methane copolymer and terephthalic acid / 2,2,4-trimethyl-1,6-hexanediamine / 2,4,4-trimethyl-1,6-hexane Mixtures with diamine copolymers, isophthalic acid / terephthalic acid / 1,6-hexanediamine copolymers are preferred, isophthalic acid / terephthalic acid / 1,6-hexanediamine / bis (3-methyl-4-aminocyclohexyl). A methane copolymer and an isophthalic acid / terephthalic acid / 1,6-hexanediamine copolymer are more preferable. As the amorphous polyamide resin, one of the above may be used alone or in combination.

By using the crystalline polyamide (A-1-1) and the amorphous polyamide (A-1-2) in combination, further improvement in fogging resistance can be achieved, for example, the haze value after the fogging test can be further increased. It can be made smaller.

The mass ratio of the crystalline polyamide (A-1-1) and the amorphous polyamide (A-1-2) is not particularly limited, and further the thermal conductivity and fogging resistance are further improved, and the bending characteristics and the molding fluidity are improved. From the viewpoint of the above, it is preferably 100/0 to 40/60, more preferably 100/0 to 55/45, more preferably 100/0 to 70/30, and even more preferably 100/0 to 80/20. By setting the ratio of crystalline polyamide (A-1-1) and amorphous polyamide (A-1-2) to the above ratio, the fogging resistance is further improved and the mechanical properties (particularly bending characteristics) are maintained. It is possible.

The relative viscosity of the thermoplastic resin (A) (particularly the polyamide resin) is not particularly limited, but from the viewpoint of improving mechanical properties (particularly bending properties) and heat resistance, 96% by mass concentrated sulfuric acid is used as a solvent and the temperature is 25. The relative viscosity measured at ° C. and a concentration of 1 g / dL is preferably 1.6 or more (particularly 1.85 or more). The relative viscosity is usually 3.5 or less, especially 3.2 or less.

The thermoplastic resin composition used in the present invention needs to contain the heat conductive filler (B) together with the thermoplastic resin (A). Examples of the thermally conductive filler (B) include talc (5 to 10), aluminum oxide (36), magnesium oxide (60), zinc oxide (25), magnesium carbonate (15), silicon carbide (160), and the like. Inorganic fillers such as aluminum nitride (170), boron nitride (210), silicon nitride (40), carbon (10 to several hundred), graphite (10 to several hundred), silver (427), copper (398), Metallic fillers such as aluminum (237), titanium (22), nickel (90), tin (68), iron (84), and stainless steel (15) can be mentioned (the numbers in parentheses are representative of thermal conductivity). Value (unit: represents W / (m · K)). These may be used alone or in combination of two or more. Among these, further improvement in thermal conductivity and economic efficiency. From the viewpoint of improvement, inorganic fillers, particularly graphite and / or talc, are preferable. Since the thermal conductivity when blended with the thermoplastic resin (A) is higher, it is more preferable to use graphite (B-1). Further, in terms of economic efficiency, it is more preferable to use talc (B-2).

The average particle size of the heat conductive filler (B) is not particularly limited, and may be, for example, 1 μm or more, particularly 1 to 200 μm. As the average particle size of the heat conductive filler (B), an average value regarding the maximum length of any 100 heat conductive fillers (B) based on microscopic observation is used.

Examples of the form of graphite include spherical shape, powder shape, fibrous shape, needle shape, scale shape, whisker shape, microcoil shape, nanotube shape and the like. Among these, scaly graphite is more preferable because it can increase the heat conduction efficiency when blended with the thermoplastic resin (A). The larger the average particle size of scaly graphite, the higher the thermal conductivity, but the mechanical properties tend to decrease, and the mechanical properties and thermal conductivity are uniform without causing agglomerates due to poor dispersion. In order to form the molded body with good processability, the average particle size of the scaly graphite is preferably 1 μm or more, more preferably 10 μm or more, still more preferably 30 μm or more. It is particularly preferably 30 to 200 μm, and most preferably 80 to 180 μm.

Examples of the morph of talc include plate-like, scaly-like, scaly-like, and flaky-like. Among these, scaly talc and flaky talc are more preferable because they tend to be oriented in the plane direction when formed into a molded body, and as a result, the thermal conductivity can be increased. The average particle size of the scaly talc is preferably 1 μm or more, more preferably 5 μm or more, and more preferably 15 μm or more for the same reason as the above-mentioned reason for the preferable average particle size of the scaly graphite. It is more preferably 15 to 70 μm, and particularly preferably 15 to 70 μm.

The thermally conductive filler (B) used in the present invention is a silane-based coupling agent or a titanium-based coupling agent in order to improve the adhesion with the thermoplastic resin (A) as long as the effect of the present invention is not impaired. The surface may be treated with. Examples of the silane coupling agent include γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, and N-β- (aminoethyl) -γ-aminopropyldimethoxymethyl. Aminosilane-based coupling agents such as silane, and epoxysilane-based cups such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane. Ring agent can be mentioned. Examples of the titanium-based coupling agent include isopropyltristearoyl titanate, isopropyltridodecylbenzenesulfonyl titanate, tetraisopropylbis (dioctylphosphite) titanate and the like. These may be used alone or in combination of two or more.

In the thermoplastic resin composition used in the present invention, the mass ratio (A / B) of the thermoplastic resin (A) and the heat conductive filler (B) needs to be 38/62 to 85/15. From the viewpoint of further improvement of thermal properties (particularly thermal conductivity) and fogging resistance, and improvement of mechanical properties (particularly bending properties) and molding processability (particularly molding fluidity), 38/62 to 75 are preferable. / 25, more preferably 45/55 to 70/30, still more preferably 48/52 to 65/35. If the amount of the heat conductive filler (B) is too large, the fogging resistance is lowered and the bending property is lowered. If the amount of the heat conductive filler (B) is too small, sufficient heat conductivity may not be obtained.

The resin composition used in the present invention may contain a fibrous reinforcing material (C) different from the heat conductive filler. Specifically, the fibrous reinforcing material (C) is a fibrous reinforcing material having non-thermal conductivity. The fact that the fibrous reinforcing material (C) has non-thermal conductivity means that the substance constituting the fibrous reinforcing material (C) has a thermal conductivity of less than 5 W / (m · K), particularly 4 W / (m · K) or less. It means having a rate.

Examples of the non-thermally conductive fibrous reinforcing material include fibers composed of inorganic fibers, organic fibers or a mixture thereof. Examples of the inorganic fiber include glass fiber and the like. Examples of the organic fiber include aramid fiber, high-density polyethylene fiber, other general polyamide, and organic fiber such as polyester. In the present invention, glass fiber is preferable from the viewpoint of being able to more effectively improve the bending characteristics when blended in the composite resin composition of the thermoplastic resin (A) and the heat conductive filler (B).

The mass ratio of the total of the thermoplastic resin (A) and the heat conductive filler (B) to the fibrous reinforcing material (C) is usually 100/0 to 50/50 parts by mass, and is heat conductive and fogging resistant. From the viewpoint of further improving the property and improving the bending property and the molding fluidity, it is preferably 100/0 to 75/25 parts by mass, and more preferably 90/10 to 75/25 parts by mass. By setting the fibrous reinforcing agent (C) in the above range, the mechanical strength and impact strength can be efficiently improved without impairing the moldability. The mass ratio of the total of the thermoplastic resin (A) and the thermally conductive filler (B) to the fibrous reinforcing material (C) is 100/0, which means that the fibrous reinforcing material (C) is not contained. do. In other words, the resin composition of the present invention may or may not contain the fibrous reinforcing material (C). When the resin composition of the present invention contains the fibrous reinforcing material (C), the total mass ratio of the polyamide resin (A) and the heat conductive filler (B) to the fibrous reinforcing material (C) is 99 /. It may be 1 to 50/50 parts by mass, particularly 98/2 to 75/25 parts by mass.

The glass fiber may be surface-treated with a silane coupling agent, a titanium-based coupling agent, a zirconia-based coupling agent, or the like in order to improve the adhesion and uniform dispersibility with the matrix resin. Fiberglass is usually used in the form of chopped strands. The cross section of the glass fiber may have any shape such as a round shape, a flat shape, a gourd shape, an eyebrows shape, an oval shape, an elliptical shape, a rectangle shape, or a similar product thereof.

The average fiber length of the glass fiber is preferably 1 to 10 mm, more preferably 1.5 to 6 mm. The fiber diameter of the glass fiber is preferably 4 to 18 μm, more preferably 7 to 15 μm. When the fiber cross section is other than round, for example, flat, gourd, eyebrows, oval, elliptical, or rectangular, the long side (for example, maximum length) and short side (for example, maximum length) in the cross-sectional shape. The ratio (that is, the aspect ratio) to the length in the vertical direction is preferably 1.5 to 10, and more preferably 2 to 8.

Addition of flame retardants, crystal nucleating agents, compatibilizers, lubricants, mold release agents, antistatic agents, antioxidants, weather resistant agents, etc. to the resin composition used in the present invention as long as the effects of the present invention are not impaired. Agents may be added.
Examples of the flame retardant include halogen-based flame retardants, aluminum hydroxide, magnesium hydroxide, inorganic flame retardants such as antimony trioxide, phosphinates and diphosphinates, and polymers thereof, polyphosphate melamine, cyanurate melamine. , Red phosphorus, phosphoric acid ester, condensed phosphoric acid ester, phosphazene compound and the like.
Examples of the crystal nucleating agent include sorbitol compounds, benzoic acid and metal salts of the compounds, and phosphoric acid ester metal salts.
Examples of the compatibilizer include ionomer-based compatibilizers, oxazoline-based compatibilizers, elastomer-based compatibilizers, reactive compatibilizers, and copolymer-based compatibilizers.
As the pigment, for example, either an organic type or an inorganic type can be used.
Examples of the antioxidant include hindered phenol-based, phosphite-based, and thioether-based antioxidants.
The weathering agent absorbs and blocks ultraviolet rays to prevent photodegradation of the resin, or captures radicals generated by ultraviolet rays or heat to suppress polymer decomposition. Examples of the weather resistant agent include an ultraviolet blocking agent, a light stabilizer, an ultraviolet absorber, and an antioxidant.
These additives may be used alone or in combination of two or more. In the present invention, the method for mixing these additives is not particularly limited.

[Manufacturing method and molded product of thermally conductive resin composition]
The heat-conducting resin composition of the present invention comprises a thermoplastic resin (A), a heat-conducting filler (B), and, if necessary, various additives, in a general extruder, for example, a uniaxial extruder. , Can be manufactured by melting and kneading using a twin-screw extruder, a roll kneader, and a thermoplastic. After melting and kneading, the melt is usually extruded into strands to be cooled and solidified, and then cut with a pelletizer to obtain the thermally conductive resin composition of the present invention in pellet form. It is effective to use a static mixer or a dynamic mixer together before melting and kneading. It is preferable to use a twin-screw extruder to improve the kneading state.

The extruder 10 has a cylinder 1 and a screw 2 arranged in the cylinder 1, for example, as shown in FIG. The material added from the main hopper 3 of the extruder 10 is melted and kneaded while being conveyed in the cylinder 1 by the rotation of the screw 2, and is discharged from the discharge port 4. The extruder 10 usually further has a side feeder 11 in the middle of the extruder 10 in the extrusion direction. In such an extruder 10, at least the thermoplastic resin (A) is usually added from the main hopper 3. The method of adding the heat conductive filler (B) and the fibrous reinforcing material (C) is not particularly limited, but the heat conductive filler (B) and the fibrous reinforcing material (C) are independently added to the hopper (the hopper (). In particular, it may be added from the main hopper 3) or from the side feeder 11. In a preferred embodiment from the viewpoint of further improvement of thermal conductivity and fogging resistance and improvement of bending characteristics and molding fluidity, the thermally conductive filler (B) is the main hopper 3 or the side feeder 11 (more preferably the side feeder). 11) When the fibrous reinforcing material (C) is added, the fibrous reinforcing material (C) is added from the side feeder 11.

In the production of the heat conductive resin composition of the present invention, a side vacuum device is used during melting and kneading by an extruder. The side vacuum device is, for example, a side vent device for a twin-screw extruder as shown in Japanese Patent No. 5645480. The side vacuum device is, specifically, as shown in FIG. 1, a device 12 for drawing a vacuum from a hole in a side portion of the extruder 10. More specifically, the side vacuum device 12 has a cylinder (not shown) and a screw (not shown) arranged inside the cylinder, and the rotation of the screw causes the melt from the extruder 10 to rotate. The pressure inside the extruder 10 can be reduced while preventing backflow. The screw of the side vacuum device 12 has a screw main body portion (that is, a screw shaft) and a blade portion (that is, a mountain portion) spirally formed on the surface of the screw main body portion. In the side vacuum device 12, the blade portion is in close contact with the inner wall of the cylinder at the tip thereof in a cross-sectional view perpendicular to the screw shaft. Therefore, the side vacuum device 12 can reduce the pressure inside the extruder 10 while preventing the backflow of the melt from the extruder 10 by reducing the pressure between the blades while rotating the screw. You can do it. In the present invention, since melting and kneading are performed using such a side vacuum device 12, even if the heat conductive filler (B) is highly filled, the heat conductive filler (B) overflows and melts. The depressurization inside the extruder is sufficiently achieved while preventing the backflow of the material. As a result, the gas in the cylinder 1 of the extruder 10 is sufficiently removed, and the residual monomer component and the pyrolyzed product component in the thermoplastic resin (A) can be sufficiently removed from the melt, so that heat conduction is sufficient. It is considered that both resistance and fogging resistance can be achieved at a sufficiently high level. Instead of using the side vacuum device 12, if a general standard-equipped vacuum device without a screw is installed in the vent port 5 and used, a heat conductive filler is blended like the resin composition of the present invention. If the amount is large, the vent portion will be blocked and gas cannot be sucked efficiently. Therefore, the fogging resistance of the obtained resin composition deteriorates.

The installation position X ₁₂ (see FIG. 1) of the side vacuum device 12 is usually 0.5 × Y to 0 when the extrusion direction distance from the main hopper 3 to the ejection port 4 in the extruder 10 is Y (mm). The position is 9.9 × Y, preferably 0.6 × Y to 0.85 × Y, more preferably 0.65 × Y to 0.80 × Y, from the viewpoint of further improving the fogging resistance. The position, more preferably the position of 0.65 × Y to 0.75 × Y.

When the extruder 10 has a side feeder 11, the installation position of the side vacuum device 12 is usually downstream of the installation position of the side feeder 11 in the extrusion direction.

Installation position _{X 11} of the side feeder 11 (see FIG. 1), when the extrusion direction distance from the main hopper 3 in the extruder 10 to the discharge port 4 was Y (mm), typically, 0.3 × Y~0. It is a position of 7 × Y, preferably a position of 0.35 × Y to 0.6 × Y, and more preferably a position of 0.40 × Y to 0.55 × Y from the viewpoint of further improving fogging resistance. , More preferably, the position is 0.40 × Y to 0.50 × Y.

In the extruder 10, the extrusion direction distance Y from the main hopper 3 to the ejection port 4 is not particularly limited, and may be, for example, 500 to 50,000 mm, particularly 1000 to 10000 mm, preferably 1000 to 5000 mm.

The degree of decompression when the side vacuum device 12 is used is a numerical value of the decompression gauge, preferably −0.06 MPa or less, still more preferably −0.08 MPa or less, from the viewpoint of further improving the fogging resistance.

The thermal conductivity of the resin composition of the present invention needs to be 2.0 W / (m · K) or more, and is preferably 5.0 W / (m · K) or more from the viewpoint of further improving the thermal conductivity. More preferably, it is 10.0 W / (m · K) or more. If the thermal conductivity is less than 2 W / (m · K), a sufficient heat dissipation effect may not be obtained when the molded product is formed. The upper limit of the thermal conductivity is not particularly limited, and the thermal conductivity is usually 50 W / (m · K) or less, particularly 45 W / (m · K) or less.

The thermal conductivity of the resin composition is the thermal conductivity of the molded product produced by using the resin composition. Specifically, the thermal conductivity of the resin composition is calculated from the thermal diffusivity α, the density ρ and the specific heat Cp in the flow direction (that is, the injection direction) in the test piece manufactured by the injection molding method in accordance with ASTM D790. The value corresponding to "α × ρ × Cp" is used.
The thermal diffusivity α may be measured by using any device as long as it can measure the thermal diffusivity in the flow direction of the molded body. For example, the laser flash method (particularly the heat constant measuring device TC-7000 (Albac Riko)) It can be measured using (manufactured by the company)).
The density ρ may be measured by any device as long as it can measure the density of the molded body, and can be measured by using, for example, an electronic hydrometer ED-120T (manufactured by Mirage Trading Co., Ltd.).
The specific heat Cp may be measured by any device as long as it can measure the specific heat of the molded body, and is elevated by using, for example, a differential scanning calorimetry method (for example, DSC-7 (manufactured by PerkinElmer)). It can be measured under the condition of a temperature rate of 10 ° C./min.

The haze value of the resin composition of the present invention needs to be 8.0 or less, and is preferably 7.5 or less, more preferably 6.5 or less, from the viewpoint of further improving the thermal conductivity. When the haze value exceeds 8.0, sufficient fogging resistance cannot be obtained when the molded product is formed. The lower limit of the heat haze value is not particularly limited, and the haze value is usually 0.1 or more, particularly 0.5 or more.

The haze value of the resin composition is the haze value of the glass plate when the molded product produced by using the resin composition is subjected to a fogging test. Specifically, the haze value of the resin composition is 200 in a high temperature environment of 125 ° C. in an air collecting bottle covered with a glass plate of 12 test pieces having a size of 50 mm × 15 mm × 2 mm manufactured by an injection molding method. The increase in the haze value on the glass plate when subjected to the time-retaining fogging test is used.
The haze value may be measured using any device as long as it can measure the haze value of the glass plate. For example, the haze value can be measured using a haze meter (Haze Meter NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd.). can.

The resin composition of the present invention can be molded into a desired shape by using a commonly known melt molding method such as injection molding, compression molding, extrusion molding, transfer molding, and sheet molding to obtain a molded product.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the Examples. The measurement methods used for the evaluation of the resin compositions of Examples and Comparative Examples are as follows.

A. Evaluation Method (1) Relative Viscosity A sample solution having a concentration of 1 g / dL was prepared by dissolving in 96% sulfuric acid. Subsequently, the drop time of the sample solution and the solvent was measured at a temperature of 25 ° C. using an Ubbelohde viscometer, and the relative viscosity was determined using the following formula.
Relative viscosity = (falling time of sample solution) / (falling time of solvent only)

(2) Density Measured at a temperature of 20 ° C. using an electron hydrometer (manufactured by Kyoto Electronics Industry Co., Ltd.).

(3) Flow length A sufficiently dried resin composition is subjected to an injection molding machine (manufactured by Nissei Plastic Industry Co., Ltd .: NEX110-12E) equipped with a bar flow test mold (spiral shape) having a width of 20 mm and a thickness of 1 mm. Injection molding was performed 10 times, and the average thereof was taken as the bar flow flow length. The cylinder temperature and the mold temperature were the temperatures shown in the table, and the injection pressure was 150 MPa. Under the same resin temperature conditions, the longer the flow length, the better the molding fluidity. The evaluation criteria for the flow length are as follows.
⊚: 115 mm or more (best);
◯: 55 mm or more and less than 115 mm (good);
X: Less than 55 mm (there is a problem in practical use).

(4) Bending strength and flexural modulus Measured in accordance with ISO standard 178. The evaluation criteria for bending strength and flexural modulus are as follows.
-Bending strength ◎: 85 MPa or more (best);
◯: 75 MPa or more and less than 85 MPa (good);
X: Less than 75 MPa (there is a problem in practical use).
-Bending elastic modulus ◎: 8 GPa or more (best);
◯: 5.5 GPa or more and less than 8 GPa (good);
X: Less than 5.5 GPa (there is a problem in practical use).

(5) Thermal conductivity (thermal conductivity of molded product)
The thermal conductivity λ was calculated by the following formula as the product of the thermal diffusivity α, the density ρ and the specific heat Cp obtained by the following methods.
λ = αρCp
λ: Thermal conductivity (W / m · K)
α: Thermal diffusivity (m ² / sec)
ρ: Density (g / m ³ )
Cp: Specific heat (J / g ・ K)
The thermal diffusivity α was specifically measured by the following method. Four bending test pieces manufactured according to ASTM D790 are hot-pressed at a temperature above the melting point of the resin using a special die having a cavity with the same width and length (length in the longitudinal direction) as the bending test piece. It was glued together. This laminated material was cut out so that the width (thickness) direction of the obtained test piece was parallel to the flow direction at the time of injection molding, and the width of the obtained test piece was 1 mm to 1.5 mm. .. Using the obtained test piece, the resin flow direction was measured by a thermal constant measuring device TC-7000 (manufactured by ULVAC Riko Co., Ltd.) based on a laser flash method. In ASTM D790, test pieces are manufactured by an injection molding method.
The density ρ was measured using an electron hydrometer ED-120T (manufactured by Mirage Trading Co., Ltd.) and a bending test piece prepared in accordance with ASTM D790.
The specific heat Cp was measured at a heating rate of 10 ° C./min using a bending test piece prepared according to a differential scanning calorimeter DSC-7 (manufactured by PerkinElmer) and ASTM D790.
The thermal conductivity in the flow direction was calculated by the above method. For each of α, ρ and Cp, an average value based on the measured values of 10 test pieces was used.
Regarding the thickness direction, the same method as the above-mentioned method for calculating the thermal conductivity in the flow direction is used, except that a sample is prepared so as to have a thickness of 1 mm to 1.5 mm using a bending test piece prepared in accordance with ASTM D790. The thermal conductivity in the thickness direction was calculated.
The thermal conductivity in the flow direction was evaluated based on the following criteria.
⊚: 10.0 or more (best);
◯: 5.0 or more and less than 10.0 (good);
Δ: 2.0 or more and less than 5.0 (no problem in practical use);
×: Less than 2.0 (there is a problem in practical use).

(6) Fogging resistance A sufficiently dried resin composition was molded into a plate molded product having a thickness of 50 mm × 90 mm × 2 mm using an injection molding machine (manufactured by Nissei Resin Industry Co., Ltd .: NEX110-12E). The two obtained compacts were cut into 6 equal parts (15 mm width) to obtain sample pieces. As shown in FIG. 2A, the sample piece 21 is placed in the air collecting bottle 22, and the sample piece 21 is placed in an oil bath 24 containing the silicone oil 23 heated to 125 ° C. in the height direction of the air collecting bottle. It was installed so that it could be used up to a height of about 80%, and the mouth of the air collecting bottle was covered with a glass plate 25 having a thickness of 2 mm. The glass plate had dimensions of 80 mm × 80 mm × 2 mm in thickness. As shown in FIG. 2B, the air collecting bottle had dimensions of a bottom surface diameter of 85 mm, a height of 150 mm, and an inner diameter of the mouth portion of 50 mm. The glass plate is not particularly limited as long as it has a size that completely covers the mouth of the air collecting bottle. Further, grease may be applied to the mouth portion of the air collecting bottle in order to improve the adhesion.
After leaving it in this state for 200 hours, the glass plate was removed from the air collecting bottle and cooled sufficiently. After sufficient cooling, the haze values at any 10 points in the portion where the air collecting bottle of the glass plate was covered were measured with a haze meter (Haze Meter NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd.). The average value of these measured values was defined as the haze value A. The average value of the haze values of any 10 points on the glass plate before being used as a lid was 0.1, and this average value was defined as the haze value B. The value of "haze value A-haze value B" was evaluated based on the following criteria.
⊚: 6.5 or less (best);
◯: More than 6.5 and 7.5 or less (good);
Δ: More than 7.5 and less than 8.0 (no problem in practical use);
×: Over 8.0 (there is a problem in practical use).

B. Raw Materials The raw materials used in the examples and comparative examples of the present invention are shown below.
(1) Thermoplastic resin (A)
-PA6: Polyamide 6 (relative viscosity 2.6, density 1.13 g / cm ³ )
PA66: Polyamide 66 resin obtained by polymerization of hexamethylenediamine and adipic acid (relative viscosity 2.8, density 1.14 g / cm ³ )
Acrylic PA: Acrylic polyamide (isophthalic acid / terephthalic acid / 1,6-hexamethylenediamine cocondensate, G21 manufactured by EMS, density 1.18 g / cm ³ )

(2) Thermally conductive filler (B)
-GrA: scaly graphite (average particle size 130 μm, thermal conductivity 100 W / m · K, density 2.25 g / cm ³ )
-GrB: scaly graphite (average particle size 40 μm, thermal conductivity 100 W / m · K, density 2.25 g / cm ³ )
TC: scaly talc (average particle size 25 μm, thermal conductivity 5-10 W / (m · K), density 2.70 g / cm ³ )

(3) Fibrous filler (C)
-GF: Glass fiber (T-262H manufactured by Nippon Electric Glass Co., Ltd., average fiber diameter 11 μm, average fiber length 3 mm)

Example 1
As shown in FIG. 1, 60 parts by mass of polyamide 6 resin (PA6) and 40 parts by mass of scaly graphite (GrA) are used in a shaft extruder (Toshiba Machinery Co., Ltd .: TEM26SS, screw diameter 26 mm, from main hopper 3 to discharge port 4. (Extrusion direction distance Y = 1380 mm) 10 was supplied to the main hopper 3 and melted and kneaded at 260 ° C. At that time, the side vacuum device 12 was used at one place. As described above, the side vacuum device 12 is a device that achieves decompression in the extruder 10 while preventing backflow of the melt from the extruder 10 by rotating the screw contained therein. The degree of decompression in the side vacuum device 12 was −0.07 MPa as the value of the decompression gauge. The installation position X ₁₂ (see FIG. 1) of the side vacuum device 12 is a position of 0.70 × Y when the extrusion direction distance from the main hopper 3 to the ejection port 4 in the extruder 10 is Y (mm). rice field. The melt was sufficiently melted and kneaded, extruded into strands to be cooled and solidified, and then cut with a pelletizer to obtain pellets of the resin composition.
For the evaluation of bending strength, thermal conductivity and fogging resistance, the obtained pellets were molded into the above-mentioned predetermined shape by a molding machine (NEX110-12E) manufactured by Nissei Resin Co., Ltd.
Pellets of resin composition were used for other evaluations and measurements.

Examples 2-14 and Comparative Examples 1-6
The same operation as in Example 1 was carried out except that the resin composition, kneading conditions, molding conditions and side vacuum apparatus (presence / absence) were changed as shown in Table 1, to obtain pellets of the resin composition.
When the fibrous reinforcing material (C) was supplied, the fibrous reinforcing material (C) was supplied by a side feeder (“11” in FIG. 1) during melting and kneading. Installation position _{X 11} of the side feeder 11 (see FIG. 1), the extrusion direction distance from the main hopper 3 in the extruder 10 to the discharge port 4 when the Y (mm), was a position of 0.45 × Y ..
When supplying fibrous reinforcement and (C), the installation position X ₁₂ of the side vacuum device 12 _(see FIG. 1) in the extrusion direction of the extruder 10, a downstream side of the installation position X ₁₁ of the side feeder, detail Was a position of 0.70 × Y when the extrusion direction distance from the main hopper 3 to the ejection port 4 in the extruder 10 was Y (mm).
When the side vacuum device was not used, a general standard-equipped vacuum device without a screw was installed at the vent port 5 and used.

Since the resin compositions of Examples 1 to 14 satisfy the requirements of the present invention, it is possible to obtain a molded product having a thermal conductivity of 2 W / (m · K) or more and excellent fogging resistance. rice field. Examples 4 to 6, Examples 8 to 10 and Example 13 contained glass fiber as a fibrous reinforcing material, and the blending amount was appropriate, so that the bending characteristics were excellent.

Since Examples 8 to 10 contain an amorphous polyamide, the haze value in the fogging test was smaller than that in Example 4 which did not contain the amorphous polyamide.

Comparing Examples 8 to 9 with Example 10, it can be seen that the molding fluidity of Example 10 is reduced due to the large mass ratio of the amorphous polyamide.

In Example 14, since a large amount of fibrous reinforcing material was contained, the bending characteristics were high, but the molding fluidity was lowered.

Since Comparative Examples 1 and 4 to 6 did not use the side vacuum device, the haze value after the fogging test was high.

In Comparative Example 2, since the mass ratio of the thermally conductive filler was larger than the range of the present invention, the haze value after the fogging test was high and the molding fluidity was also lowered.
In Comparative Example 3, the mass ratio of the thermally conductive filler was smaller than the range of the present invention, so that sufficient thermal conductivity could not be obtained.

Specific examples of the molded body obtained by molding the resin composition of the present invention include electrical and electronic parts such as sockets, relay parts, coil bobbins, optical pickups, oscillators, and computer-related parts; VTRs, televisions, irons, and the like. Household electrical appliances such as air conditioners, stereos, copiers, refrigerators, rice cookers, and lighting fixtures; heat dissipation members for releasing heat from electronic parts such as heat dissipation sheets, heat sinks, and fans; lamp sockets, lamp reflectors, lamps Lighting equipment parts such as housings; Audio product parts such as compact discs, laser discs (registered trademarks), speakers; Communication equipment parts such as ferrules for optical cables, mobile phones, fixed phones, facsimiles, modems; Separation claws, heater holders, etc. Copier / printing machine related parts; Mechanical parts such as impellers, fan gears, gears, bearings, motor parts and cases, and mechanical parts for automobiles; Automotive parts such as engine parts, engine room parts, electrical parts, interior parts, etc.; Cooking utensils such as microwave cooking pots and heat-resistant tableware; parts for space equipment and sensor parts in aircraft and spacecraft.

Claims (9)

A thermally conductive resin composition containing a thermoplastic resin (A) and a thermally conductive filler (B).
The mass ratio of the thermoplastic resin (A) to the thermally conductive filler (B) is 38/62 to 85/15.
The haze value of the glass plate after the fogging test at 125 ° C. for 200 hours is 8 or less.
A heat conductive resin composition having a heat conductivity of 2 W / (m · K) or more in the flow direction of a molded body obtained by molding the heat conductive resin composition. The thermally conductive filler (B) is talc, aluminum oxide, magnesium oxide, zinc oxide, magnesium carbonate, silicon carbide, aluminum nitride, boron nitride, silicon nitride, carbon, graphite, silver, copper, aluminum, titanium, nickel. The thermally conductive resin composition according to claim 1, which is one or more materials selected from the group consisting of, tin, iron, and stainless steel. The thermally conductive resin composition further contains a non-thermally conductive fibrous reinforcing material (C), and the sum of the thermoplastic resin (A) and the thermally conductive filler (B) and the non-thermally conductive material. The heat conductive resin composition according to claim 1 or 2, wherein the mass ratio with the fibrous reinforcing material (C) is 100/0 to 50/50. The heat conductive resin composition according to claim 3, wherein the non-heat conductive fibrous reinforcing material (C) is glass fiber. The thermally conductive resin composition according to any one of claims 1 to 4, wherein the thermoplastic resin (A) is a polyamide. Claims 1 to 1, wherein the thermoplastic resin (A) is composed of a crystalline polyamide and an amorphous polyamide, and the mass ratio of the crystalline polyamide to the amorphous polyamide is 100/0 to 40/60. 5. The thermally conductive resin composition according to any one of 5. The mass ratio of the thermoplastic resin (A) to the thermally conductive filler (B) is 38/62 to 75/25.
The heat conductive resin composition according to any one of claims 1 to 6, wherein the heat conductive filler (B) is graphite. The mass ratio of the thermoplastic resin (A) to the thermally conductive filler (B) is 45/55 to 70/30.
The thermally conductive filler (B) is scaly graphite having an average particle size of 80 to 180 μm.
The thermally conductive resin composition further contains a non-thermally conductive fibrous reinforcing material (C).
Claim 1 in which the mass ratio of the total of the thermoplastic resin (A) and the thermally conductive filler (B) to the non-thermally conductive fibrous reinforcing material (C) is 100/0 to 75/25. The thermally conductive resin composition according to any one of 7 to 7. A molded product made of the thermally conductive resin composition according to any one of claims 1 to 8.

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