JP4929670B2 - Polyarylene sulfide composition - Google Patents

Description

  The present invention is excellent in thermal conductivity, dimensional stability, heat resistance, mold releasability, and melt fluidity, generates a small amount of gas during melting (hereinafter referred to as low gas property), and has thermal conductivity. The present invention relates to a polyarylene sulfide composition having low anisotropy and thermal expansibility. More particularly, the present invention relates to a polyarylene sulfide composition that is particularly useful for electric parts such as electric / electronic parts or automobile electric parts.

  Polyarylene sulfide is a resin that exhibits excellent properties such as heat resistance, chemical resistance, and moldability, and is used widely in electrical and electronic equipment members, automotive equipment members, OA equipment members, etc. by taking advantage of its superior properties. ing.

  However, since polyarylene sulfide has low thermal conductivity, for example, when an electronic component with heat generation is sealed, the generated heat cannot be efficiently diffused, dimensional change due to thermal expansion, deformation due to heat, Alternatively, problems such as gas generation may occur.

  Several attempts have been made to improve the thermal conductivity of polyarylene sulfide. For example, (a) polyphenylene sulfide, (b) alumina powder having an average particle size of 5 μm or less, and (c) fiber. There has been proposed a resin composition containing a reinforcing material (see, for example, Patent Document 1). One type selected from (a) polyarylene sulfide, (b) carbon fiber having a specific tensile modulus, and (c) graphite, metal powder, alumina, magnesia, titania, dolomite, boron nitride, and aluminum nitride. A resin composition containing the above filler has been proposed (see, for example, Patent Document 2). Further, a resin composition in which (a) a resin composed of polyphenylene sulfide and polyphenylene ether, (b) carbon fiber having a specific thermal conductivity, and (c) graphite is proposed (see, for example, Patent Document 3). .)

Japanese Unexamined Patent Publication No. 04-033958 JP 2002-129015 A JP 2004-137401 A

  However, in the methods proposed in Patent Documents 1 to 3, the thermal conductivity of the composition is low, the thermal conductivity is anisotropic, and the thermal expansion of the composition is large. There was a problem that sufficient dimensional stability could not be obtained.

  Therefore, the present invention is a polyarylene sulfide having excellent thermal conductivity, dimensional stability, heat resistance, mold releasability, low gas property and melt fluidity, and low thermal conductivity anisotropy and thermal expansion. An object of the present invention is to provide a polyarylene sulfide composition that is particularly useful for electrical component applications such as electrical / electronic components or automotive electrical components.

  As a result of intensive studies to solve the above problems, the present inventors have found that polyarylene sulfide, carnauba wax, carbon fibers having a specific thermal conductivity and / or scaly boron nitride powder having a specific structure, and By making a polyarylene sulfide composition comprising magnesite powder having a specific magnesium carbonate content, it has low anisotropy and high thermal conductivity, thermal expansion and low anisotropy, and gold The present inventors have found that the composition can be excellent in mold releasability and have completed the present invention.

That is, the present invention comprises (a) polyarylene sulfide 20 to 50% by weight , (b) carnauba wax 0.05 to 5% by weight , (c) carbon fibers having a thermal conductivity of 100 W / m · k or more and / or Or 5 to 50% by weight of flaky boron nitride powder having a hexagonal crystal structure and (d) magnesite containing magnesium carbonate as a main component and having a magnesium carbonate content of 98 to 99.999% by weight The present invention relates to a polyarylene sulfide composition for injection molding characterized by comprising 15 to 70% by weight of magnesite powder.

  Hereinafter, the present invention will be described in detail.

  The polyarylene sulfide composition of the present invention comprises (a) polyarylene sulfide, (b) carnauba wax, (c) carbon fibers having a thermal conductivity of 100 W / m · k or more and / or a scale-like structure having a hexagonal crystal structure. Boron nitride powder and (d) magnesite containing magnesium carbonate as a main component, the magnesium carbonate content being 98 to 99.999% by weight.

  As the polyarylene sulfide (a) constituting the polyarylene sulfide composition of the present invention, any polyarylene sulfide may be used as long as it belongs to the category called polyarylene sulfide. Since the composition was excellent in mechanical strength and moldability, it was measured with a Koka flow tester using a die having a diameter of 1 mm and a length of 2 mm under the conditions of a measurement temperature of 315 ° C. and a load of 10 kg. Polyarylene sulfide having a melt viscosity of 50 to 3000 poise is preferable, and one having a melt viscosity of 60 to 1500 poise is particularly preferable.

  The polyarylene sulfide (a) preferably contains 70 mol% or more, particularly 90 mol% or more of a p-phenylene sulfide unit represented by the following general formula (1) as a structural unit.

そして、他の構成成分としては、例えば、下式の一般式（２）に示されるｍ−フェニレンスルフィド単位、

Examples of other components include m-phenylene sulfide units represented by the following general formula (2):

一般式（３）に示されるｏ−フェニレンスルフィド単位、

O-phenylene sulfide unit represented by the general formula (3),

一般式（４）に示されるフェニレンスルフィドスルホン単位、

A phenylene sulfide sulfone unit represented by the general formula (4),

一般式（５）に示されるフェニレンスルフィドケトン単位、

A phenylene sulfide ketone unit represented by the general formula (5),

一般式（６）に示されるフェニレンスルフィドエーテル単位、

A phenylene sulfide ether unit represented by the general formula (6),

一般式（７）に示されるジフェニレンスルフィド単位、

A diphenylene sulfide unit represented by the general formula (7),

一般式（８）に示される置換基含有フェニレンスルフィド単位、

A substituent-containing phenylene sulfide unit represented by the general formula (8),

（ここで、ＲはＯＨ、ＮＨ_２、ＣＯＯＨ、ＣＨ_３を示し、ｎは１又は２を示す。）
一般式（９）に示される分岐構造含有フェニレンスルフィド単位、

(Here, R represents OH, NH ₂ , COOH, CH ₃ , and n represents 1 or 2)
A branched structure-containing phenylene sulfide unit represented by the general formula (9):

等を含有していてもよく、中でもポリ（ｐ−フェニレンスルフィド）が好ましい。

In particular, poly (p-phenylene sulfide) is preferable.

  The method for producing the (a) polyarylene sulfide is not particularly limited. For example, the polyarylene sulfide may be produced by a method of reacting an alkali metal sulfide and a dihaloaromatic compound in a generally known polymerization solvent. Possible alkali metal sulfides include, for example, lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide and mixtures thereof, which may be used in the form of hydrates. These alkali metal sulfides are obtained by reacting an alkali metal hydrosulfide with an alkali metal base, and can be prepared in situ prior to addition of the dihaloaromatic compound into the polymerization system, or outside the system. You can use the adjusted one. Examples of the dihaloaromatic compound include p-dichlorobenzene, p-dibromobenzene, p-diiodobenzene, m-dichlorobenzene, m-dibromobenzene, m-diiodobenzene, 1-chloro-4-bromobenzene, 4,4'-dichlorodiphenyl sulfone, 4,4'-dichlorodiphenyl ether, 4,4'-dichlorobenzophenone, 4,4'-dichlorodiphenyl and the like. The charging ratio of the alkali metal sulfide and the dihaloaromatic compound is preferably in the range of alkali metal sulfide / dihaloaromatic compound (molar ratio) = 1.00 / 0.90 to 1.10.

  As the polymerization solvent, a polar solvent is preferable, and an organic amide which is aprotic and stable to alkali at high temperature is particularly preferable. Examples of the organic amide include N, N-dimethylacetamide, N, N-dimethylformamide, hexamethylphosphoramide, N-methyl-ε-caprolactam, N-ethyl-2-pyrrolidone, and N-methyl-2-pyrrolidone. 1,3-dimethylimidazolidinone, dimethyl sulfoxide, sulfolane, tetramethylurea and mixtures thereof. Moreover, it is preferable to use this polymerization solvent in 150-3500 weight% with respect to the polymer produced | generated by superposition | polymerization, and it is preferable to use especially in the range used as 250-1500 weight%. The polymerization is preferably carried out at 200 to 300 ° C., particularly 220 to 280 ° C. for 0.5 to 30 hours, particularly 1 to 15 hours with stirring.

  Furthermore, even if the (a) polyarylene sulfide is linear or is treated and crosslinked at a high temperature in the presence of oxygen, a slight amount of trihalo or higher polyhalo compound is added to form a slight crosslink. Alternatively, a branched structure may be introduced, a heat treatment may be performed in a non-oxidizing inert gas such as nitrogen, or a mixture of these structures may be used.

  The blending amount of (a) polyarylene sulfide constituting the polyarylene sulfide composition of the present invention is 20 to 50% by weight because it becomes a polyarylene sulfide composition particularly excellent in mechanical strength, moldability, and thermal conductivity. It is preferable that

  (B) Carnauba wax constituting the polyarylene sulfide composition of the present invention is blended in order to improve mold releasability and appearance of a molded product obtained from the polyarylene sulfide composition, (B) As a carnauba wax, a general commercial product can be used. For example, (trade name) purified carnauba No. 1 powder (manufactured by Nikko Fine Products) can be used. The blending amount of the (b) carnauba wax is less likely to cause problems such as mold contamination during the molding process, and becomes a polyarylene sulfide composition excellent in mold releasability and molded article appearance. It is preferable that it is 05 to 5 weight%.

  The polyarylene sulfide composition of the present invention is a carbon fiber having a thermal conductivity of 100 W / m · k or more (hereinafter referred to as carbon fiber (c)) and / or a flaky boron nitride powder having a hexagonal crystal structure ( Hereinafter, the scaly boron nitride powder (referred to as “c”) is blended.

  Here, as the carbon fiber (c), any carbon fiber having a thermal conductivity of 100 W / m · k or more can be used without any limitation. Carbon fibers can be broadly classified into polyacrylonitrile, pitch, rayon, polyvinyl alcohol and the like, and any of these may be used as long as the thermal conductivity is 100 W / m · k or more, preferably the pitch system. Carbon fiber. When carbon fiber having a thermal conductivity of less than 100 W / m · k is used to form a polyarylene sulfide composition, it is combined with (d) a high-purity magnesite powder having a magnesium carbonate content of 98 to 99.999% by weight. Even if blended, a polyarylene sulfide composition having high thermal conductivity cannot be obtained, and the object of the present invention cannot be achieved.

  Examples of the shape of the carbon fiber (c) include a chopped fiber having a fiber diameter of 5 to 20 μm and a fiber length of 2 to 8 mm, a milled fiber having a fiber diameter of 5 to 20 μm and a fiber length of 30 to 150 μm. Chopped fiber is preferred because it provides a polyarylene sulfide composition with excellent mechanical strength.

On the other hand, the scaly boron nitride powder (c) can be used without any limitation as long as it has a hexagonal crystal structure, and the scaly boron nitride powder (c) is, for example, The crude boron nitride powder is heat-treated in a nitrogen atmosphere in the presence of an alkali metal or alkaline earth metal borate at 2000 ° C. for 3 to 7 hours to sufficiently develop the boron nitride crystal, and after grinding, necessary Accordingly, it can be produced by purifying with a strong acid such as nitric acid, and the boron nitride powder thus obtained usually has a scaly shape. The scaly boron nitride powder (c) is a polyarylene sulfide composition having excellent dispersibility of the scaly boron nitride powder (c) in the polyarylene sulfide composition of the present invention and excellent mechanical properties. Therefore, it is preferable that the average particle diameter (D ₅₀ ) measured by the laser diffraction scattering method is 3 to 30 μm. Moreover, since the scaly boron nitride powder (c) exhibits a high crystallinity and can be a polyarylene sulfide composition having particularly excellent thermal conductivity, it is obtained by a powder X-ray diffraction method. (102) G represented by the ratio of the sum of the integrated intensity values of (100) diffraction line and (101) diffraction line [I _{(100) + (101)} ] to the integrated intensity value [I ₍₁₀₂₎ ] of the diffraction line . It is preferable that I value (GI = [I _{(100) + (101)} ] / [I ₍₁₀₂₎ ]) is in the range of 0.8-10.

  Furthermore, in the polyarylene sulfide composition of the present invention, the carbon fiber (c) and the scaly boron nitride powder (c) may be used alone or simultaneously. The blending amount of carbon fiber (c) and / or scaly boron nitride powder (c) constituting the polyarylene sulfide composition of the present invention is particularly polyarylene excellent in mechanical strength, moldability and thermal conductivity. Since it becomes a sulfide composition, it is preferable that it is 5 to 50 weight%.

The magnesite powder constituting the polyarylene sulfide composition of the present invention is a magnesite containing magnesium carbonate as a main component and having a magnesium carbonate content of 98 to 99.999% by weight (hereinafter referred to as “magnesite powder”). High purity magnesite powder (d)), and can be used without any limitation as long as the above conditions are satisfied. The high-purity magnesite powder (d) includes synthetic products and natural products, and any of these may be used. For example, (trade name) synthetic magnesite MSHP (manufactured by Kamishima Chemical Co., Ltd.) is preferred. As an example. Here, as the magnesite powder, when a magnesite powder having a magnesium carbonate content outside the range of 98 to 99.999% by weight is used as the polyarylene sulfide composition, even if carbon fiber (c) and / or scaly nitriding is performed. Even when blended in combination with the boron powder (c), a polyarylene sulfide composition having high thermal conductivity cannot be obtained. Moreover, as a high purity magnesite powder (d), since it becomes a polyarylene sulfide composition excellent in heat conductivity in particular, the average particle diameter (D ₅₀ ) measured by a laser diffraction scattering method is 1 μm or more. In particular, those having a thickness of 10 μm or more are preferred.

  The high-purity magnesite powder (d) may be further surface-treated with a silane coupling agent, a titanate coupling agent, or an aluminate coupling agent as necessary. Examples of the agent include vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-mercaptopropyltrimethoxysilane, and titanate. Examples of the coupling agent include isopropyl triisostearoyl titanate, and examples of the aluminate coupling agent include acetoalkoxyaluminum diisopropylate.

  The blending amount of the high-purity magnesite powder (d) constituting the polyarylene sulfide composition of the present invention is 15 to 70 because it becomes a polyarylene sulfide composition excellent in mechanical strength, moldability and thermal conductivity. It is preferable that it is weight%.

  Furthermore, in the polyarylene sulfide composition of the present invention, it is preferable that (e) graphite is blended in order to make the thermal conductivity anisotropy smaller. There is no restriction | limiting in particular as this (e) graphite, What kind of thing can be used if a thermal conductivity anisotropy can be made small. Graphite is roughly classified into natural graphite and artificial graphite. Natural graphite includes, for example, earthy graphite, scale-like graphite, scale-like graphite, and any of these may be used. The fixed carbon content of the (e) graphite is a graphite having a fixed carbon content of 95% or more because it becomes a polyarylene sulfide composition having particularly excellent thermal conductivity and low anisotropy. It is preferable. In addition, the particle diameter of the (e) graphite is preferably a polyarylene sulfide composition having particularly excellent thermal conductivity, so that the average particle diameter of primary particles is 0.5 to 400 μm.

  When the (e) graphite is blended with the polyarylene sulfide composition of the present invention, the blending amount becomes a polyarylene sulfide composition with particularly low mechanical strength, moldability, and thermal conductivity anisotropy. It is preferable that it is 5 to 40 weight%.

  The polyarylene sulfide composition of the invention is within a range not departing from the object of the present invention, various thermosetting resins, thermoplastic resins such as epoxy resins, cyanate ester resins, phenol resins, polyimides, silicone resins, polyolefins, polyesters, One or more of polyamide, polyphenylene oxide, polycarbonate, polysulfone, polyetherimide, polyethersulfone, polyetherketone, polyetheretherketone and the like can be mixed and used.

  As a method for producing the polyarylene sulfide composition of the present invention, a conventionally used hot melt kneading method can be used. Examples thereof include a heat-melt kneading method using a single-screw or twin-screw extruder, a kneader, a mill, a Brabender, etc., and a melt kneading method using a twin screw extruder excellent in kneading ability is particularly preferable. Moreover, the kneading | mixing temperature in this case is not specifically limited, Usually, it can select arbitrarily from 280-400 degreeC. Moreover, the polyarylene sulfide composition of the present invention can be molded into an arbitrary shape using an injection molding machine, an extrusion molding machine, a transfer molding machine, a compression molding machine, or the like.

  In the polyarylene sulfide composition of the present invention, fibrous or non-fibrous reinforcing materials can be used without departing from the object of the present invention. Examples of the fibrous reinforcing material include glass fiber, alumina fiber, potassium titanate whisker, aluminum borate whisker, and zinc oxide whisker. Examples of the non-fibrous reinforcing material include calcium carbonate, mica, silica, talc, calcium sulfate, kaolin, clay, wollastonite, zeolite, glass beads, and glass powder. These reinforcing materials can be used in combination of two or more, and can be used after surface treatment with a silane-based or titanium-based coupling agent if necessary. Particularly preferred reinforcing materials are glass fibers for fibrous reinforcing materials and calcium carbonate and talc for non-fibrous reinforcing materials.

  Furthermore, the polyarylene sulfide composition of the present invention is a conventionally known release agent, lubricant, thermal stabilizer, antioxidant, ultraviolet absorber, crystal nucleating agent, foaming agent, within the range not departing from the object of the present invention. One or more additives such as mold corrosion inhibitors, flame retardants, flame retardant aids, colorants such as dyes and pigments, and antistatic agents may be used in combination.

  The polyarylene sulfide composition of the present invention is particularly suitable for a semiconductor element having high exothermic property, a sealing resin such as a resistor, or a component that generates high frictional heat, as well as a generator, an electric motor, a transformer, a current transformer. Especially suitable for electrical equipment parts applications such as transformers, voltage regulators, rectifiers, inverters, relays, power contacts, switches, circuit breakers, knife switches, other pole rods, electrical parts cabinets, sockets, resistors, relay cases Sensors, LED lamps, connectors, small switches, coil bobbins, capacitors, variable capacitor cases, optical pickups, oscillators, various terminal boards, transformers, plugs, printed circuit boards, tuners, speakers, microphones, headphones, small motors, magnetics Head base, power module, semiconductor, liquid crystal, FDD carriage, FDD Chassis, hard disk drive parts (hard disk drive hubs, actuators, hard disk substrates, etc.), DVD parts (optical pickups, etc.), motor brush holders, parabolic antennas, computer-related electronic parts; VTR parts, TV parts, irons , Hair dryer, rice cooker parts, microwave oven parts, acoustic parts, audio equipment parts such as audio / laser discs (registered trademark) / compact discs, lighting parts, refrigerator parts, air conditioner parts, typewriter parts, word processor parts, etc. Home, office electrical product parts; office computer-related parts, telephone-related parts, facsimile-related parts, copier-related parts, cleaning jigs, motor parts, lighters, typewriters, etc. Representative machine-related parts: Optical instruments such as microscopes, binoculars, cameras, watches, precision machine-related parts: Alternator terminals, alternator connectors, IC regulators, light meter potentiometer bases, exhaust gas valves, etc. Valves, fuel-related / exhaust / intake system pipes, air intake nozzle snorkel, intake manifold, fuel pump, engine coolant joint, carburetor main body, carburetor spacer, exhaust gas sensor, coolant sensor, oil temperature sensor, brake pad Wear sensor, throttle position sensor, crankshaft position sensor, air flow meter, brake pad wear sensor, thermostat base for air conditioner, warm air flow -Control valve, brush holder for radiator motor, water pump impeller, turbine vane, wiper motor related parts, distributor, starter switch, starter relay, transmission wiring harness, window washer nozzle, air conditioner panel switch board, fuel related electromagnetic valve Coils, fuse connectors, horn terminals, electrical component insulation plates, step motor rotors, lamp sockets, lamp reflectors, lamp housings, brake pistons, solenoid bobbins, engine oil filters, ignition device cases, etc. It can be applied to various purposes.

  The present invention is a polyarylene sulfide composition having excellent thermal conductivity, dimensional stability, heat resistance, mold releasability, low gas properties and melt fluidity, and low thermal conductivity anisotropy and thermal expansion. The polyarylene sulfide composition is particularly useful for electrical parts such as electrical / electronic parts or automotive electrical parts.

  EXAMPLES Next, although an Example and a comparative example demonstrate this invention, this invention is not restrict | limited to these examples at all.

  In Examples and Comparative Examples, (a) polyphenylene sulfide, (b) carnauba wax, (c) carbon fiber having a thermal conductivity of 100 W / m · k or more, and flaky boron nitride powder having a hexagonal structure, (c ') The following were used as carbon fiber having a thermal conductivity of less than 100 W / m · k, (d) magnesite powder, and (e) graphite.

<(A) Polyphenylene sulfide>
(A-1) Poly (p-phenylene sulfide) (hereinafter simply referred to as PPS (a-1)): Melt viscosity 110 poise.
(A-2) Poly (p-phenylene sulfide) (hereinafter simply referred to as PPS (a-2)): melt viscosity of 300 poise.
(A-3) Poly (p-phenylene sulfide) (hereinafter simply referred to as PPS (a-3)): Melt viscosity poise 350 poise.

<(B) Carnauba wax>
(B-1) Carnauba wax (hereinafter simply referred to as Carnauba wax (b-1)); (trade name) purified carnauba No. 1 powder manufactured by Nikko Fine Products.

<(C) Scaled boron nitride powder having a carbon fiber having a thermal conductivity of 100 W / m · k or more and a hexagonal crystal structure>
(C-1) Carbon fiber having a thermal conductivity of 100 W / m · k or more (hereinafter simply referred to as high thermal conductivity carbon fiber (c-1)); (trade name) DIALEAD, manufactured by Mitsubishi Chemical Corporation K6331T; thermal conductivity 140 W / m · k, chopped fiber, fiber diameter 10 μm, fiber length 6 mm.
(C-2) scale-like boron nitride powder having a hexagonal crystal structure (hereinafter, simply referred to as scale-like boron nitride powder (c-2)); manufactured by Denki Kagaku Kogyo Co., Ltd. (trade name) DENKABORON NITRIDE SGP: average particle diameter 18.0 μm, specific surface area 2 m ² / g, G. I value of 0.9.

<(C ′) Carbon fiber having a thermal conductivity of less than 100 W / m · k>
(C′-1) Carbon fiber having a thermal conductivity of less than 100 W / m · k (hereinafter simply referred to as low thermal conductivity carbon fiber (c′-1)); manufactured by Mitsubishi Chemical Corporation (trade name) DIALEAD K223SE; thermal conductivity 20 W / m · k, chopped fiber, fiber diameter 10 μm, fiber length 6 mm.

<(D) Magnesite powder>
(D-1) Magnesite powder (hereinafter simply referred to as high-purity magnesite powder (d-1)); manufactured by Kamishima Chemical Co., Ltd., (trade name) synthetic magnesite MSHP; magnesium carbonate content 99. 99% by weight, average particle size 12 μm.
(D-2) Magnesite powder (hereinafter, simply referred to as high-purity magnesite powder (d-2)); manufactured by Kamijima Chemical Co., Ltd., (trade name) synthetic magnesite MSL; magnesium carbonate content 99. 7% by weight, average particle size 8 μm.
(D-3) Magnesite powder (hereinafter, simply referred to as magnesite powder (d-3)); manufactured by Kamishima Chemical Co., Ltd., (trade name) heavy magnesium carbonate; magnesium carbonate content 86.8 wt. %, Average particle diameter 11 μm.

<(E) Graphite>
(E-1) Graphite (hereinafter referred to as unit graphite (e-1)); manufactured by Showa Denko KK, (trade name) UFG-30; artificial graphite, fixed carbon content 99.4%.

  Evaluation and measurement methods used in Examples and Comparative Examples are shown below.

~ Measurement of bending strength ~
A test piece having a length of 127 mm, a width of 12.7 mm, and a thickness of 3.2 mm was prepared by injection molding, and the bending strength was measured using the test piece according to ASTM D-790 Method-1 (three-point bending method). did. Using a measuring device (manufactured by Shimadzu Corporation, (trade name) AG-5000B), the test was performed under the test conditions of a distance between fulcrums of 50 mm and a measurement speed of 1.5 mm / min.

~ Measurement of thermal conductivity ~
Using a thermal conductivity measuring device (manufactured by ULVAC, (trade name) TC7000; ruby laser), measurement was performed by a laser flash method at 23 ° C. For the thermal conductivity in the thickness direction, the heat capacity Cp and the thermal diffusivity α in the thickness direction are obtained by a one-dimensional method, and for the thermal conductivity in the plane direction, the thermal diffusivity α ′ in the plane direction is obtained by a two-dimensional method. Thus, the thermal diffusivity was calculated from the following equation.
Thermal conductivity in the thickness direction = ρ × Cp × α
Thermal conductivity in the plane direction = ρ × Cp × α ′
Here, the density ρ was measured according to ASTM D-792 A method (underwater substitution method). Moreover, the test piece used for a measurement cut from the flat plate used for the following linear expansion coefficient. Furthermore, in order to evaluate the anisotropy of the thermal conductivity, the ratio (thickness direction) / (plane direction) of the thermal conductivity was calculated. The closer the value was to 100%, the smaller the anisotropy. Conversely, when the value was close to 0% or greatly exceeded 100%, the anisotropy was judged to be large.

~ Measurement of linear expansion coefficient ~
A flat plate having a length of 70 mm, a width of 70 mm, and a thickness of 2 mm is produced by injection molding. From the flat plate, a width of 5 mm and a length of 15 mm are respectively obtained in the resin flow direction (MD) and the direction perpendicular to the resin flow direction (TD). A strip-shaped plate was cut out and used as a test piece for measuring the linear expansion coefficient. Next, the test piece was attached to a measuring device ((trade name) DL7000, manufactured by ULVAC, Inc.), and the linear expansion coefficient was measured in the range of 30 to 200 ° C. under a temperature rising condition of 2 ° C./min. Furthermore, in order to evaluate the anisotropy of the linear expansion coefficient, the (MD) / (TD) ratio of the linear expansion coefficient is calculated. The closer the value is to 100%, the smaller the anisotropy is. When near or greatly exceeding 100%, the anisotropy was judged to be large.

~ Measurement of bending strength ~
A test piece having a length of 127 mm, a width of 12.7 mm, and a thickness of 3.2 mm was prepared by injection molding, and the bending strength was measured using the test piece according to ASTM D-790 Method-1 (three-point bending method). did. The measuring device (trade name) AG-5000B (manufactured by Shimadzu Corporation) was used, and the test was performed under the test conditions of a distance between fulcrums of 50 mm and a measurement speed of 1.5 mm / min.

~ Measurement of melt flow rate (MFR) ~
Using a Koka flow tester, the weight (g unit) of the composition flowing out in 10 minutes was measured under the conditions of a temperature of 315 ° C., a load of 5 kg, and a die inner diameter of 2.0 mm, and a melt flow rate (hereinafter referred to as MFR). It was written.)

<Synthesis Example 1 (Synthesis of PPS (a-1), PPS (a-2))>
A 15 liter autoclave equipped with a stirrer was charged with 1866 g of Na ₂ S · 2.8H ₂ O and 5 liters of N-methyl-2-pyrrolidone (hereinafter referred to as NMP), and gradually raised to 205 ° C. while stirring under a nitrogen stream. Warm and distill 407 g of water. After cooling the system to 140 ° C., 2280 g of p-dichlorobenzene and 1500 g of NMP were added, and the system was sealed under a nitrogen stream. The system was heated to 225 ° C. and polymerized at 225 ° C. for 2 hours. After completion of the polymerization, the mixture was cooled to room temperature, and the polymer was isolated using a centrifuge. The polymer was washed repeatedly with warm water and dried at 100 ° C. for a whole day and night to obtain poly (p-phenylene sulfide).

  The melt viscosity of the obtained poly (p-phenylene sulfide) (PPS (a-1)) was 110 poise.

  Further, PPS (a-1) was heat-cured at 235 ° C. in an air atmosphere. The melt viscosity of the obtained poly (p-phenylene sulfide) (PPS (a-2)) was 300 poise.

<Synthesis Example 2 (Synthesis of PPS (a-3))>
A 15 liter titanium autoclave equipped with a stirrer was charged with 3232 g of NMP, 1682 g of a 47% aqueous solution of sodium hydrogen sulfide and 1142 g of a 48% aqueous solution of sodium hydroxide. Distilled. The system was cooled to 170 ° C., 2118 g of p-dichlorobenzene and 1783 g of NMP were added, and the system was sealed under a nitrogen stream. The system was heated to 225 ° C., polymerized at 225 ° C. for 1 hour, then heated to 250 ° C. and polymerized at 250 ° C. for 2 hours. Furthermore, 451 g of water was injected at 250 ° C., the temperature was raised again to 255 ° C., and polymerization was carried out at 225 ° C. for 2 hours. After completion of the polymerization, the mixture was cooled to room temperature, and the polymerization slurry was separated into solid and liquid. The polymer was washed successively with NMP, acetone and water, and dried at 100 ° C. overnight to obtain poly (p-phenylene sulfide).

  The obtained poly (p-phenylene sulfide) (PPS (a-3)) was linear, and its melt viscosity was 350 poise.

Example 1
Blended in a proportion of 42.7% by weight of PPS (a-2), 1.3% by weight of carnauba wax (b-1) and 56% by weight of high-purity magnesite powder (d-1) and heated to 310 ° C. Into the hopper of the twin screw extruder (Toshiba Machine, (trade name) TEM-35-102B), on the other hand, the high thermal conductivity carbon fiber (c-1) is put into the hopper of the twin screw extruder side feeder. Melt-kneading was performed at a rotational speed of 200 rpm, and the molten composition flowing out from the die was cooled and cut to prepare a pellet-shaped polyarylene sulfide composition. The composition ratio of the polyarylene sulfide composition at that time was PPS (a-2) / carnauba wax (b-1) / high purity magnesite powder (d-1) / high thermal conductive carbon fiber (c-1) = 32. / 1/42/25 (% by weight).

  The polyarylene sulfide composition was put into a hopper of an injection molding machine (manufactured by Sumitomo Heavy Industries, Ltd., (trade name) SE75S) heated to 310 ° C., and a test piece for measuring bending strength, and thermal conductivity Each flat plate for measuring the linear expansion coefficient was molded.

  Bending strength, thermal conductivity, and linear expansion coefficient were measured from the test piece and the flat plate. Further, the polyarylene sulfide composition was charged into a Koka flow tester and MFR was measured. These results are shown in Table 1.

  The obtained polyarylene sulfide composition had a sufficiently high bending strength, a high thermal conductivity, and a small anisotropy. Moreover, the linear expansion coefficient was small and the anisotropy was also small. Furthermore, MFR also showed a practically sufficient value.

Examples 2-10
PPS (a-1, 2, 3), carnauba wax (b-1), high thermal conductivity carbon fiber (c-1), scaly boron nitride powder (c-2), high purity magnesite powder (d-1, 2) A polyarylene sulfide composition and a test piece for evaluation shown in Table 1 were prepared and evaluated by the same method as in Example 1 except that graphite (e-1) was used. The evaluation results are shown in Table 1.

  All the obtained polyarylene sulfide compositions had high thermal conductivity and low linear expansion coefficient. Moreover, each anisotropy was also small.

比較例１〜６
ＰＰＳ（ａ−１，２）、カルナバワックス（ｂ−１）、高熱伝導炭素繊維（ｃ−１）、鱗片状窒化ホウ素粉末（ｃ−２）、低熱伝導炭素繊維（ｃ’−１）、高純度マグネサイト粉末（ｄ−１）、マグネサイト粉末（ｄ−３）を用いた以外は、実施例１と同様の方法により、表２に示す構成割合のポリアリーレンスルフィド組成物、評価用試験片を作成し、評価した。評価結果を表２に示す。

Comparative Examples 1-6
PPS (a-1, 2), carnauba wax (b-1), high thermal conductivity carbon fiber (c-1), scaly boron nitride powder (c-2), low thermal conductivity carbon fiber (c′-1), high A polyarylene sulfide composition having the composition ratios shown in Table 2 and a test piece for evaluation were obtained in the same manner as in Example 1 except that pure magnesite powder (d-1) and magnesite powder (d-3) were used. Was created and evaluated. The evaluation results are shown in Table 2.

  (C) a composition not containing the high thermal conductivity carbon fiber and scaly boron nitride powder obtained by Comparative Example 1, (d) a composition not containing the high purity magnesite powder obtained by Comparative Example 2, Comparative Example 3 (C ′) composition obtained by mixing the low thermal conductive carbon fiber obtained by the above, composition containing the magnesite powder whose magnesium carbonate content obtained by Comparative Examples 4 and 5 is out of the range of 98 to 99.999% by weight Each of the objects had a low thermal conductivity and a large anisotropy. Moreover, the linear expansion coefficient was also large. Furthermore, the composition (b) obtained by Comparative Example 6 that does not contain carnauba wax has poor mold releasability, so that the test piece and flat plate used for each evaluation cannot be molded, bending strength, thermal conductivity, And the linear expansion coefficient could not be evaluated.

Claims (3)

(A) Polyarylene sulfide 20 to 50% by weight , (b) Carnauba wax 0.05 to 5% by weight , (c) Carbon fiber having a thermal conductivity of 100 W / m · k or more and / or a hexagonal crystal structure Scaly boron nitride powder 5 to 50% by weight , and (d) high purity magnesite powder 15 to 70 having magnesium carbonate as a main component and having a magnesium carbonate content of 98 to 99.999% by weight. injection molding the polyarylene sulfide composition characterized in that it consists by weight%. (A) Polyarylene sulfide 20 to 50% by weight, (b) Carnauba wax 0.05 to 5% by weight, (c) Carbon fiber having a thermal conductivity of 100 W / m · k or more and / or a hexagonal crystal structure 5 to 50% by weight of flaky boron nitride powder, (d) high-purity magnesite powder having a magnesium carbonate content of 98 to 99.999% by weight and having a magnesium carbonate content of 98 to 99.999% by weight The polyarylene sulfide composition for injection molding according to claim 1, wherein the composition comprises 5% by weight and 5% by weight of (e) graphite . An injection-molded article obtained by injection-molding the polyarylene sulfide composition for injection molding according to claim 1 or 2 .