JP2008133382A - Heat-conductive resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly heat-conductive material having a heat-insulating property and excellent in moldability and friction properties. <P>SOLUTION: The heat-conductive resin composition is obtained by adding (B) 10-200 pts.wt. fibrous titanium oxide having ≥3 W/m*K and ≥10 aspect ratio and (C) 10-400 pts.wt. plate-like and/or spherical and/or amorphous heat-conductive filler having ≥2 W/m*K heat conductivity to (A) 100 pts.wt. liquid crystalline polymer, wherein total addition amount of components (B) and (C) is 30-500 pts.wt. based on 100 pts.wt. liquid crystalline polymer (A). The composition has ≥0.8 W/m*K heat conductivity. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an insulating heat conductive resin composition having excellent moldability and wear characteristics. More specifically, the present invention relates to heat conductivity used in various automobile parts, electrical and electronic parts, etc. that require heat dissipation. The present invention relates to an excellent liquid crystalline polymer composition.

  A liquid crystalline polymer capable of forming an anisotropic molten phase is known as a material that is excellent in dimensional accuracy and vibration damping properties among thermoplastic resins, and generates very little burrs during molding. Conventionally, taking advantage of such characteristics, liquid crystal polymer compositions reinforced with glass fibers have been widely used as materials for various electric and electronic parts. However, in recent years, these parts have been made lighter, thinner, and smaller, and heat radiation inside the parts has become a problem, and there has been a demand for materials having heat radiation properties.

  For this reason, a method has been proposed in which alumina having a specific particle size is added to a thermoplastic resin to improve moldability and thermal conductivity (Patent Document 1), but this method improves moldability. Since the Mohs hardness of alumina is high, the extruder, the screw of the molding machine, the cylinder, and the molding die are severely worn during kneading with the resin and molding, and there is a problem that metal is mixed.

  On the other hand, a method has been proposed in which graphite is mixed with a liquid crystalline polymer to impart thermal conductivity (Patent Document 2). Although this method does not cause wear of a screw or the like by a filler, electric conductivity is simultaneously provided with thermal conductivity. Since conductivity is imparted, there is a problem that it cannot be used in fields where electrical insulation is required.

  Further, although it has been proposed to add a thermal conductive filler having an aspect ratio of 5 or more to a thermoplastic resin (Patent Document 3), only PBO (polybenzazole) fibers are listed as examples. Other fibrous thermal conductive fillers have not been studied, and the fibrous filler alone has a problem that the fluidity is remarkably lowered when a large amount of filler is added to improve thermal conductivity.

In addition, it has been proposed that amorphous titanium oxide is added to a thermoplastic resin to improve light reflectivity and light shielding properties and to be used as a photocatalyst (Patent Documents 4 and 5). No consideration has been made.
JP 2002-146187 A JP 2006-257174 A JP 2006-116894 A JP 2004-75770 A JP 2003-253130 A

  An object of the present invention is to solve the drawbacks of the prior art and to provide a highly heat-conductive material that is insulative and has excellent moldability and wear characteristics.

  In view of the above-mentioned problems, the present inventors diligently searched for and studied a liquid crystalline polymer composition having excellent moldability and wear characteristics and high thermal conductivity. It has been found that it is extremely effective to combine a conductive filler with a specific plate-like, spherical, and irregular-shaped thermally conductive filler, and the present invention has been completed.

That is, the present invention
(A) For 100 parts by weight of the liquid crystalline polymer,
(B) 10 to 200 parts by weight of fibrous titanium oxide having a thermal conductivity of 3 W / m · K or more and an aspect ratio of 10 or more,
(C) Addition of 10 to 400 parts by weight of one or more kinds of plate-like, spherical and irregular shapes having a thermal conductivity of 2 W / m · K or more,
The total addition amount of the components (B) and (C) is 30 to 500 parts by weight with respect to 100 parts by weight of the liquid crystalline polymer (A), and the thermal conductivity is 0.8 W / m · K or more. It is an insulating heat conductive resin composition.

  Hereinafter, the present invention will be described in detail. The liquid crystalline polymer (A) used in the present invention refers to a melt processable polymer having a property capable of forming an optically anisotropic molten phase. The property of the anisotropic molten phase can be confirmed by a conventional polarization inspection method using an orthogonal polarizer. More specifically, the anisotropic molten phase can be confirmed by using a Leitz polarizing microscope and observing a molten sample placed on a Leitz hot stage under a nitrogen atmosphere at a magnification of 40 times. When the liquid crystalline polymer applicable to the present invention is inspected between crossed polarizers, the polarized light is normally transmitted even in the molten stationary state, and optically anisotropic.

  The liquid crystalline polymer (A) is not particularly limited, but is preferably an aromatic polyester or an aromatic polyester amide, and an aromatic polyester or a polyester partially containing the aromatic polyester amide in the same molecular chain. Is also in that range. They preferably have a logarithmic viscosity (IV) of at least about 2.0 dl / g, more preferably 2.0-10.0 dl / g when dissolved in pentafluorophenol at 60 ° C. at a concentration of 0.1% by weight. .) Are used.

  The aromatic polyester or aromatic polyester amide as the liquid crystalline polymer (A) applicable to the present invention is particularly preferably at least one selected from the group consisting of aromatic hydroxycarboxylic acids, aromatic hydroxyamines and aromatic diamines. An aromatic polyester or aromatic polyester amide having the above compound as a constituent component.

More specifically,
(1) A polyester mainly composed of one or more aromatic hydroxycarboxylic acids and derivatives thereof;
(2) mainly (a) one or more of aromatic hydroxycarboxylic acids and derivatives thereof; and (b) one or more of aromatic dicarboxylic acids, alicyclic dicarboxylic acids and derivatives thereof; c) Polyester comprising at least one or more of aromatic diol, alicyclic diol, aliphatic diol and derivatives thereof;
(3) mainly (a) one or more aromatic hydroxycarboxylic acids and derivatives thereof; (b) one or more aromatic hydroxyamines, aromatic diamines and derivatives thereof; and (c). A polyesteramide comprising one or more of aromatic dicarboxylic acid, alicyclic dicarboxylic acid and derivatives thereof;
(4) mainly (a) one or more aromatic hydroxycarboxylic acids and derivatives thereof; (b) one or more aromatic hydroxyamines, aromatic diamines and derivatives thereof; and (c). One or more of aromatic dicarboxylic acid, alicyclic dicarboxylic acid and derivatives thereof; and (d) at least one or more of aromatic diol, alicyclic diol, aliphatic diol and derivatives thereof, and The polyesteramide which consists of, etc. are mentioned. Furthermore, you may use a molecular weight modifier together with said structural component as needed.

  Specific examples of the specific compound constituting the liquid crystalline polymer (A) applicable to the present invention include aromatic hydroxycarboxylic acids such as p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid, 2,6- Aromatic diols such as dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 4,4′-dihydroxybiphenyl, hydroquinone, resorcinol, compounds represented by the following general formula (I) and the following general formula (II); terephthalic acid, isophthal Aromatic dicarboxylic acids such as acids, 4,4′-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid and compounds represented by the following general formula (III); aromatics such as p-aminophenol and p-phenylenediamine Examples include amines.

(However, X: alkylene (C1 -C4), alkylidene, -O-, -SO -, - SO 2 -, -S -, - CO- than group _{selected, Y :-( CH 2) n -} (n = 1~4), - O (CH 2) n O- (n = 1~4) from the group selected)
Particularly preferred liquid crystalline polymer (A) to which the present invention is applied is a fragrance comprising p-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 4,4′-dihydroxybiphenyl, terephthalic acid as a main constituent component. A polyester.

  Next, (B) fibrous titanium oxide used in the present invention, the thermal conductivity is important. When the thermal conductivity is low, improvement in thermal conductivity as a resin composition to which a filler is added can hardly be expected. Therefore, the thermal conductivity of fibrous titanium oxide is 3 W / m · K or more, preferably 10 W / m. -K or more. In addition, the aspect ratio is also important, and if it is too small, the heat transfer path in the resin composition is difficult to develop, and there is a problem that there is little improvement in the thermal conductivity of the resin composition. Preferably 15 or more is necessary. Fibrous titanium oxide satisfies the above-mentioned conditions, does not give adverse effects such as decomposition on the liquid crystalline polymer, and does not have conductivity, and is selectively used as the fibrous thermal conductive filler of the component (B) in the present invention. Used for.

  Moreover, although it is the addition amount of fibrous titanium oxide, since a heat transfer path in the resin composition does not develop if the addition amount is too small, sufficient thermal conductivity cannot be exhibited, and conversely if too much, Although the entanglement becomes intense and the thermal conductivity increases, the problem that the molding fluidity is remarkably lowered, the problem that the pressure in the extruder rises at the time of kneading and the kneading property is extremely deteriorated, the fiber breaks due to the thickening of the resin composition, Problems such as a decrease in thermal conductivity occur. Therefore, the amount of (B) fibrous titanium oxide added is 10 to 200 parts by weight, preferably 20 to 150 parts by weight, more preferably 20 to 100 parts by weight, based on 100 parts by weight of (A) liquid crystalline polymer. Most preferably, it is 30 to 100 parts by weight.

  Next, the (C) plate-like, spherical, and amorphous heat conductive filler used in the present invention is the reason why the plate-like, spherical, and amorphous heat conductive filler is added. (B) Fibrous titanium oxide However, the thermal conductivity in the direction of the fiber is increased by itself, but the improvement in the thermal conductivity in the direction perpendicular to the direction is reduced. Therefore, by adding a filler that spreads in two or more directions of plate, sphere, and amorphous, the resin composition It is possible to give uniform thermal conductivity as a product, and adding only a large amount of fibrous titanium oxide causes a significant decrease in fluidity as described above, so it has excellent moldability and high thermal conductivity. It is difficult to obtain a resin composition having Therefore, the thermal conductivity of the plate-like, spherical, and irregular-shaped thermally conductive fillers is as important as the fibrous titanium oxide. If the thermal conductivity is low, it is difficult to transfer the heat transferred by the fibrous heat conductive filler, and the heat transfer at that portion becomes rate-limiting. Therefore, the thermal conductivity of the plate-like / spherical / indeterminate thermally conductive filler is 2 W / m · K or more, preferably 3 W / m · K or more.

  In addition, it is the amount of plate-like, spherical, and amorphous heat conductive filler added, but if the amount added is too small, the heat transfer path in the resin composition does not develop, so that sufficient heat conductivity is not exhibited, On the other hand, if the amount is too large, the fiber breaks due to the thickening of the resin composition, but rather the problem that the thermal conductivity decreases, the problem that the pressure in the extruder rises during kneading, and the kneadability becomes extremely worse occurs. Therefore, the addition amount of (C) plate-like, spherical, and amorphous heat conductive filler is 10 to 400 parts by weight, preferably 20 to 100 parts by weight, more preferably 100 parts by weight of (A) liquid crystalline polymer. Preferably it is 30-80 weight part.

  As the (C) plate-like, spherical, and amorphous heat conductive filler that can be used in the present invention, any material that satisfies the above conditions can be used. Specific materials include talc, anhydrous magnesium carbonate, magnesium oxide, alumina, silica, beryllia, boron nitride, silicon carbide, aluminum nitride, etc. Among these, from the viewpoint of filler hardness, toxicity and economy Talc, anhydrous magnesium carbonate, and magnesium oxide are preferred.

  If the total amount of (B) fibrous titanium oxide and (C) plate-like, spherical, and amorphous heat-conducting fillers is too small, the thermal conductivity will not be improved. As the total addition amount satisfies the above addition amount of each of the components (B) and (C), (A) 30 to 500 parts by weight with respect to 100 parts by weight of the liquid crystalline polymer. Parts, preferably 50 to 250 parts by weight, more preferably 50 to 200 parts by weight.

  Next, anhydrous magnesium carbonate to be used as the component (C) is generally known. It is known that magnesium carbonate exists as a trihydrate and releases its crystal water at 100 ° C. Therefore, when general magnesium carbonate is mixed in the resin, troubles such as foaming and decomposition of the resin occur due to the release of crystal water, and kneading cannot be performed. However, anhydrous magnesium carbonate used in the present invention is obtained by treating general magnesium carbonate existing as a trihydrate salt under high temperature and high pressure to form anhydrous crystals, and does not have the above-mentioned problems. Anhydrous magnesium carbonate produced by such a method is generally available as high-purity magnesite MSL (manufactured by Kamishima Chemical Co., Ltd.).

  Next, magnesium oxide used as the component (C) can be used as it is, but it is preferable to use phosphorus-containing coated magnesium oxide in order to improve wet heat resistance. The phosphorus-containing coated magnesium oxide used in the present invention is obtained by coating a surface with a double oxide by melting at a high temperature in the presence of a compound that forms a double oxide on the surface of the magnesium oxide. . Specifically, the compound that forms the double oxide is wet-added to the magnesium oxide powder, and then mixed and stirred, or the compound that forms the double oxide is present on the surface of the magnesium oxide. It can be manufactured by a method of firing at a temperature equal to or higher than the melting point of the material.

  The compound used to form the double oxide is preferably one or more compounds selected from the group consisting of aluminum compounds, iron compounds, silicon compounds and titanium compounds. The form of the compound is not limited, but nitrate, sulfate, chloride, oxynitrate, oxysulfate, oxychloride, hydroxide, oxide, etc. are used. Specific examples of this compound include fumed silica, aluminum nitrate, iron nitrate and the like.

  The method for producing phosphorus-containing coated magnesium oxide is obtained by subjecting magnesium oxide having a coating layer made of magnesium oxide or a double oxide produced by the above method to surface treatment with a phosphorus compound, and a magnesium phosphate compound on the surface thereof. To form a coating layer.

  Examples of the phosphorus compound used for the surface treatment include phosphoric acid, phosphate, and acidic phosphate ester. These may be used alone or in combination of two or more. Examples of the phosphate include sodium phosphate, potassium phosphate, and ammonium phosphate. Examples of the acidic phosphate ester include isopropyl acid phosphate, methyl acid phosphate, ethyl acid phosphate, propyl acid phosphate, and butyl acid phosphate. Lauryl acid phosphate, stearyl acid phosphate, 2-ethylhexyl acid phosphate, oleyl acid phosphate and the like. Among these, isopropyl acid phosphate is preferable because a coating layer having excellent water resistance can be easily formed.

  As a specific method of the surface treatment with a phosphorus compound of phosphorus-containing coated magnesium oxide, a predetermined amount of phosphorus compound is added to magnesium oxide having a coating layer made of magnesium oxide or a double oxide, for example, after stirring for 5 to 60 minutes, It is performed by baking at a temperature of 300 ° C. or higher for 0.5 to 5 hours.

  The phosphorus-containing coated magnesium oxide produced by such a method is generally available as Cool Filler CF2-100A (Tateho Chemical Industry Co., Ltd.).

  Next, in the present invention, it is preferable to further add (D) an alkoxysilane compound from the viewpoint of improving the heat and moisture resistance. The effect is particularly remarkable when phosphorus-containing coated magnesium oxide is used as the component (C).

  The alkoxysilane compound used in the present invention may be at least one selected from the group consisting of aminoalkoxysilane, vinylalkoxysilane, epoxyalkoxysilane, mercaptoalkoxysilane, and allylalkoxysilane.

  Any aminoalkoxysilane may be used as long as it is a silane compound having one or more amino groups in one molecule and having two or three alkoxy groups. For example, γ-aminopropyltrimethoxysilane, γ -Aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltri And methoxysilane. Any vinylalkoxysilane can be used as long as it is a silane compound having one or more vinyl groups in one molecule and having two or three alkoxy groups. For example, vinyltrimethoxysilane, vinyltriethoxysilane. Vinyltris (β-methoxyethoxy) silane and the like. As the epoxyalkoxysilane, any silane compound having one or more epoxy groups in one molecule and having two or three alkoxy groups is effective. For example, γ-glycidoxypropyltrimethoxysilane , Β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and the like. Any mercaptoalkoxysilane may be used as long as it is a silane compound having one or more mercapto groups in one molecule and having two or three alkoxy groups. For example, γ-mercaptopropyltrimethoxysilane, γ -Mercaptopropyltriethoxysilane and the like. Any arylalkoxysilane is effective as long as it is a silane compound having one or more allyl groups in one molecule and having two or three alkoxy groups, such as γ-diallylaminopropyltrimethoxysilane, Examples include γ-allylaminopropyltrimethoxysilane, γ-allylthiopropyltrimethoxysilane, and the like. For the purpose of the present invention, among the alkoxysilane compounds, aminoalkoxysilane is most preferable.

  In the present invention, the addition amount of the alkoxysilane compound is important. If the amount of the alkoxysilane compound is small, the mechanical properties after the PCT are remarkably lowered. On the other hand, if the amount is too large, the resin is thickened and the moldability is remarkably lowered. Therefore, the addition amount of an alkoxysilane compound is 0.1-5 weight part with respect to 100 weight part of (A) liquid crystalline polymer, Preferably it is 0.4-4 weight part.

  In addition, the high thermal conductive resin composition of the present invention is within the object range of the present invention in order to improve performance such as mechanical strength, heat resistance, dimensional stability (deformation resistance, warpage), and electrical properties. B) and inorganic or organic fillers other than the components (C) may be blended, and for this purpose, fibrous, granular or plate-like fillers are used depending on the purpose.

  In addition, known substances generally added to thermoplastic resins, that is, flame retardants, colorants such as dyes and pigments, stabilizers such as antioxidants and ultraviolet absorbers, lubricants, crystallization accelerators, crystal nucleating agents, etc. Also, those appropriately added according to the required performance can be used as the composition of the present invention.

  A molded product obtained by injection molding, extrusion molding, blow molding or the like using the heat conductive resin composition of the present invention thus obtained has high moisture and heat resistance, chemical resistance, dimensional stability, difficulty. Shows flammability and excellent heat dissipation. Taking advantage of this advantage, it can be suitably used for components that radiate internally generated heat, such as heat exchangers, heat sinks, and optical pickups.

  Other applications include, for example, LEDs, sensors, connectors, sockets, terminal blocks, printed circuit boards, motor parts, ECU cases and other electrical / electronic parts, lighting parts, TV parts, rice cooker parts, microwave oven parts, iron parts, etc. It can be used for household and office electrical product parts such as copier-related parts, printer-related parts, facsimile-related parts, heaters, and air conditioner parts.

Next, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited to these. In addition, the method of the physical property measurement in an Example is as follows.
(1) Thermal conductivity Thermal conductivity was measured by a hot disk method using a sample in which disk-shaped molded products having a diameter of 30 mm and a thickness of 2 mm were stacked.
(2) Injection moldability Under the conditions of a cylinder temperature of 370 ° C and an injection speed of 15 m / min, a rod-shaped molded product with a width of 5 mm, a thickness of 0.3 mm and a maximum flow distance of 70 mm is molded, and the flow distance is measured. did.
(3) Moist heat resistance
Using an ISO standard test piece of 80 × 10 × 4 mm, a pressure cooker test is performed for 48 hours under the conditions of 121 ° C., 100% humidity and 2 atmospheres, and the bending strength of the test piece is measured according to ISO 178. The retention rate relative to the initial value was determined.
Examples 1-6, Comparative Examples 1-5
A liquid crystal polymer, a thermally conductive filler and an alkoxysilane compound are kneaded with the composition shown in Table 1 using a twin screw extruder (TEX30α type, manufactured by Nippon Steel Co., Ltd.) to form pellets, and then an injection molding machine The above-mentioned test pieces were molded and various evaluations were performed. The results are shown in Table 1.

In addition, each component used and the alkoxysilane compound addition method are as follows.
(A) Liquid crystalline polymer (LCP)
S950 manufactured by Polyplastics Co., Ltd., thermal conductivity 0.45 W / m · K
(B) Fibrous titanium oxide Acicular titanium oxide: FTL-300 manufactured by Ishihara Sangyo Co., Ltd., fiber diameter 0.27 μm, fiber length 5.15 μm, thermal conductivity 20 W / m · K
(C) Plate, Spherical, and Amorphous Thermally Conductive Filler Talc; Crown Talc PP manufactured by Matsumura Sangyo Co., Ltd., plate, average particle size 8 μm, thermal conductivity 3.2 W / m · K
Anhydrous magnesium carbonate; high purity magnesite MSL (anhydrous magnesium carbonate synthetic product) manufactured by Kamishima Chemical Industry Co., Ltd., irregular shape, average particle size 8 μm, thermal conductivity 15 W / m · K
Phosphorus-containing coated magnesium oxide; manufactured by Tateho Chemical Co., Ltd. CF2-100A, spherical, average particle size 27 μm, maximum particle size 100 μm, thermal conductivity 35 W / m · K
Titanium oxide; TITON SR-1, manufactured by Sakai Chemical Industry Co., Ltd., irregular shape, average particle size 0.25 μm, thermal conductivity 20 W / m · K
(D) Aminosilane compound 3-Aminopropyltriethoxysilane

Claims (5)

(A) For 100 parts by weight of the liquid crystalline polymer,
(B) 10 to 200 parts by weight of fibrous titanium oxide having a thermal conductivity of 3 W / m · K or more and an aspect ratio of 10 or more,
(C) Addition of 10 to 400 parts by weight of one or more kinds of plate-like, spherical and irregular shapes having a thermal conductivity of 2 W / m · K or more,
The total addition amount of the components (B) and (C) is 30 to 500 parts by weight with respect to 100 parts by weight of the liquid crystalline polymer (A), and the thermal conductivity is 0.8 W / m · K or more. Insulating heat conductive resin composition.   (B) Component addition amount is 20 to 100 parts by weight, (C) Component addition amount is 20 to 100 parts by weight, and (B) and (C) component total addition amount is 50 to 200 parts by weight. The insulating heat conductive resin composition according to claim 1.   (C) The insulative heat conductive resin composition according to claim 1 or 2, wherein the plate-like, spherical, and amorphous heat-conductive filler is at least one selected from talc, anhydrous magnesium carbonate and magnesium oxide. .   The insulating heat conductive resin composition according to claim 3, wherein the magnesium oxide is phosphorus-containing coated magnesium oxide.   Furthermore, the thermal conductive resin composition of Claim 4 formed by mix | blending 0.1-5 weight part of (D) alkoxysilane compounds with respect to 100 weight part of (A) liquid crystalline polymer.