JP6116881B2 - Insulation case - Google Patents

Description

  The present invention relates to an insulating case, and more specifically, heat generated from a heating element such as a bus bar or a coil in a device that handles a large current is efficiently transmitted to a heat radiating member such as a heat sink. The present invention relates to an insulating case made of a thermally conductive resin composition that can be suitably used to ensure insulation from a heat radiating member.

  Since electric and electronic devices such as power converters and chargers used in hybrid vehicles and electric vehicles handle large currents, the amount of heat generated from heating elements such as bus bars and coils is large, and electric heat such as metal heat sinks is used. There are many cases where heat is dissipated using a conductive heat dissipating member. In that case, in order to ensure the insulation between heat generating bodies or between a heat generating body and a heat radiating member, it is necessary to interpose an insulator. Generally, a resin material with low thermal conductivity is used as the insulator, but the insulating case for molding or housing the heating element preferably transfers the generated heat to the heat radiating member efficiently. 1 describes the use of a highly thermally conductive resin as an insulator for molding a bus bar. In this case, the insulating case is required to have high thermal conductivity in the thickness direction. In addition, since the normal use temperature is close to 150 ° C., long-term heat resistance of 150 ° C. is required for the insulating case.

  In order to solve such problems, attempts have been widely made to obtain a highly thermally conductive resin composition by blending a large amount of a thermally conductive filler into a thermoplastic resin. As the thermally conductive filler, a thermally conductive filler such as graphite, carbon fiber, alumina, boron nitride or the like is usually blended in the resin at a high content of 30% by volume or more, and further 50% by volume or more. There is a need. However, even when a large amount of filler is blended, it is difficult to increase the thermal conductivity in the thickness direction in particular because the thermal conductivity of the resin alone is low. In Patent Document 2, a resin composition containing a Sn—Cu alloy, a metal powder having a melting point of 400 ° C. and / or carbon fiber, a hexagonal boron nitride powder, and a magnesium oxide powder as a low melting point alloy has high thermal conductivity in the thickness direction. It is described that it has. However, since a low melting point alloy, metal powder, or carbon fiber is used, it becomes a non-insulator and cannot be used for an insulating case. Patent Document 3 or 4 describes that the anisotropy of thermal conductivity is reduced with respect to a resin composition containing a spherical or particle-shaped thermally conductive filler and a plate-like thermally conductive filler. However, since the thermal conductivity of the base resin is low, there is a problem that it is difficult to improve the thermal conductivity in the thickness direction. Therefore, improvement of the thermal conductivity of the base resin has been demanded.

  Patent Document 5 describes that a thermoplastic resin having a specific structure exhibits high thermal conductivity as a single resin, and that the thermal conductivity of the resin composition is greatly improved by blending a thermal conductive filler. It is described in Non-patent Documents 1 to 3 that many of the described thermoplastic resins exhibit smectic liquid crystallinity when heated. However, no mention is made of the long-term heat resistance at 150 ° C. of the resin material.

JP 2006-031959 A JP 2007-070587 A Special table 2011-503328 gazette JP 2012-136684 A International Publication Number WO2010 / 050202

Journal of Polymer Science Polymer Physics Edition, 21, 1119-1131 (1983) Macromolecules, 16, 1271-1279 (1983) Macromolecules, 17, 2288-2295 (1984).

An object of the present invention is to provide an insulating case having high thermal conductivity and insulation in the thickness direction and long-term heat resistance of 150 ° C.

As a result of diligent research to solve the above problems, it was found that a thermoplastic resin exhibiting smectic liquid crystal properties when heated has high thermal conductivity as a single resin and excellent long-term heat resistance at high temperatures. . Based on this discovery, a spherical or granular heat conductive filler, a fibrous filler and a needle, which are characterized in that the transition point from the crystalline phase to the smectic liquid crystal phase is 180 ° C. or more. An insulating case made of a thermoplastic resin composition containing a specific amount of at least one reinforcing material selected from the group consisting of fillers of the shape is excellent in long-term heat resistance at 150 ° C. and has high thermal conductivity in the thickness direction. And found the present invention.
That is, the present invention includes the following 1) to 13).

  1) Spheric or granular thermal conductivity with respect to 100 parts by weight of the thermoplastic resin (A), which exhibits smectic liquid crystallinity upon heating and has a transition point from the crystal phase to the smectic liquid crystal phase of 180 ° C. or higher. Thermally conductive resin containing 50 to 250 parts by weight of filler (B1) and 10 to 100 parts by weight of at least one reinforcing material (C) selected from the group consisting of fibrous fillers and needle-like fillers An insulating case made of the composition.

  2) The insulating case according to 1), wherein the thermally conductive resin composition further contains 5 to 100 parts by weight of a flame retardant (D).

  3) The thermally conductive resin composition further contains 20 to 200 parts by weight of a plate-like thermally conductive filler (B2), and the content ratio with the spherical or granular thermally conductive filler (B1) is a volume ratio. (B1) / (B2) = 5/95 to 70/30, wherein 1) or 2).

  4) The insulating case according to any one of 1) to 3), wherein the spherical or granular thermally conductive filler (B1) is magnesium oxide having a water absorption rate of 0.5% or less.

  5) The insulating case according to 3) or 4), wherein the plate-like thermally conductive filler (B2) is at least one selected from talc and hexagonal boron nitride.

  6) The insulating case according to any one of 1) to 5), wherein the reinforcing material (C) is at least one selected from the group consisting of glass fiber, wollastonite, potassium titanate whisker, and aluminum borate whisker. .

  7) The insulating case according to any one of 1) to 6), wherein the heat conductive resin composition has a bending strength retention of 85% or more after heat treatment at 150 ° C. for 2000 hours in an air atmosphere.

8) The insulating case according to any one of 1) to 7), wherein the structure of the main chain of the thermoplastic resin is mainly composed of repeating units represented by the general formula (1).
-M-Sp- . . . (1)
(In the formula, M represents a mesogenic group, and Sp represents a spacer.)
9) The insulating case according to 8), wherein the thermoplastic resin is mainly composed of repeating units represented by the following general formula (2).
_{^{-A 1 -x-A 2 -OCO (}} CH 2) m COO- . . . (2)
(In the formula, A ¹ and A ² each independently represent a substituent selected from an aromatic group, a condensed aromatic group, an alicyclic group, and an alicyclic heterocyclic group. Bond, —O—, —S—, —CH ₂ —CH ₂ —, —C═C—, —C═C (Me) —, —C≡C—, —CO—O—, —CO—NH—. , —CH═N—, —CH═N—N═CH—, —N═N— or —N (O) ═N—, wherein m represents 2 to 20. Indicates an integer.)
10) The thermoplastic resin molded article according to 9), wherein -A ¹ -xA ² -of the thermoplastic resin is represented by the following general formula (3).

(In the formula, each R is independently an aliphatic hydrocarbon group, F, Cl, Br, I, CN, or NO ₂ , y is an integer of 2 to 4, and n is an integer of 0 to 4.)
11) The insulating case according to any one of 9) or 10), wherein m of the thermoplastic resin is at least one selected from an even number of 4 to 14.

  12) The insulating case according to any one of 1) to 11), wherein the thermoplastic resin has a number average molecular weight of 3000 to 40000.

  13) A power module formed by using the insulating case according to any one of 1) to 12).

  The insulating case of the present invention is not only excellent in thermal conductivity in the thickness direction, but also retains strength by long-term heat treatment at 150 ° C., and thus can be applied to electric / electronic devices that handle large currents. Contributes to downsizing or higher performance of equipment.

  The insulating case of the present invention exhibits a smectic liquid crystal property when heated, and has a transition point from a crystalline phase to a smectic liquid crystal phase of 180 ° C. or more, which is spherical or granular with respect to 100 parts by weight of the thermoplastic resin (A). 50 to 250 parts by weight of the thermally conductive filler (B1) and 10 to 100 parts by weight of at least one reinforcing material (C) selected from the group consisting of a fibrous filler and an acicular filler. It is characterized by comprising a thermally conductive resin composition.

  The thermoplasticity referred to in the present invention is a property of plasticizing by heating. The thermoplastic resin in the present invention can be a smectic liquid crystal in the liquid crystal phase. A smectic liquid crystal is called a smectic layer in which molecules are arranged almost parallel to the molecular axis, and the center of gravity of the parallel connected parts is on the same plane and has a layer state substantially perpendicular to the molecular axis. It has a layer structure. It is known that smectic liquid crystals exhibit a peculiar pattern such as a batonets structure, a mosaic structure, a fan-like structure, etc. in microscopic observation under orthogonal polarization. In addition, a diffraction peak derived from the period of the smectic layer is observed from wide-angle X-ray diffraction measurement in a liquid crystal state.

The thermophysical properties of a thermoplastic resin exhibiting smectic liquid crystallinity generally indicate a transition point T _S from a solid phase to a smectic liquid crystal phase and a transition point T _i from a smectic liquid crystal phase to an isotropic phase in the temperature rising process. . Some resins also indicate transition point T _N to nematic liquid crystal phase from the smectic liquid crystal phase at a temperature lower than T _i. These phase transition points can be confirmed as the peak top of the endothermic peak in the temperature rising process of DSC measurement.

By "characterized by transition from the crystalline phase to the smectic liquid crystal phase is 180 ° C. or more" of the present invention means that the T _S is 180 ° C. or higher, preferably 190 ° C. or higher, more preferably 200 degreeC or more is preferable at the point of 150 degreeC long-term heat resistance. Although from the standpoint of long-term heat resistance T _S is preferably as high as possible, it is preferred that the T _S from the viewpoint of moldability of the resin material is 350 ° C. or less, more preferably 330 ° C. or less, 310 ° C. or less More preferably.

  Most of the liquid crystalline resins that have been put to practical use so far have nematic liquid crystalline properties, and most of them have a fully aromatic molecular structure, so there is a transition point from the solid phase to the liquid crystal phase. Many of them had a temperature of 250 ° C. or higher, and therefore many had long-term heat resistance of 150 ° C. However, a resin that becomes nematic liquid crystalline when melted, for example, has its molecular chain oriented due to shear flow in the mold during injection molding. However, even if a thermally conductive filler is blended, heat in the thickness direction of the resin composition can be obtained. The conductivity is not greatly improved. On the other hand, as described in Patent Document 5 and Non-Patent Documents 1 to 3, since a flexible group such as a methylene chain exists in the molecular structure of many thermoplastic resins exhibiting smectic liquid crystallinity, the liquid crystal phase is changed from the solid phase. The transition temperature to is lower than that of nematic liquid crystalline resins, and many of them have a high temperature of around 200 ° C. It was an unexpected discovery that such a smectic liquid crystalline resin exhibiting a relatively low solid phase-liquid crystal phase transition temperature has a long-term heat resistance of 150 ° C. Furthermore, when a thermally conductive filler is blended with a resin exhibiting smectic liquid crystallinity, the thermal conductivity of the resin composition is greatly improved.

Thermoplastic resin (A) in the present invention is a crystal phase is less than T _S. Crystalline thermoplastic resin exhibiting a smectic liquid crystallinity, since at temperatures below T _S becomes relatively high crystallinity, thereby believed to have a long-term heat resistance of 0.99 ° C.. From this viewpoint, the degree of crystallinity at room temperature (25 ° C.) is preferably 20% or more, more preferably 40% or more, and further preferably 60% or more. The degree of crystallinity is obtained from the X-ray diffraction measurement by the Ruland method.

  The resin composition in the present invention is characterized by containing a spherical or granular heat conductive filler (B1). When the shape of the thermally conductive filler is spherical or granular, the thermal conductivity can be increased in the thickness direction even when the resin composition is formed into a thin wall. The thermal conductivity in the thickness direction is preferably 2.0 W / (m · K) or more, more preferably 2.2 W / (m · K) or more, and 2.5 W / (m · K). More preferably, it is more preferably 3.0 W / (m · K) or more.

  The usage-amount of a heat conductive filler (B1) is 50-250 weight part with respect to 100 weight part of thermoplastic resins (A), Preferably it is 60-200 weight part, More preferably, it is 70-150 weight part. If it is less than 50 parts by weight, the thermal conductivity in the thickness direction of the insulating case will be insufficient, and if it exceeds 250 parts by weight, the molding processability will be deteriorated, and the extruder and mold used for compounding with the resin will wear. cause.

  The average particle diameter of the thermally conductive filler (B1) is preferably in the range of 10 μm to 100 μm, more preferably 20 μm to 80 μm, and particularly preferably 30 μm to 60 μm. If it is less than 10 μm, the thermal conductivity of the insulating case may be insufficient, and if it exceeds 100 μm, the moldability may be deteriorated.

  Examples of the heat conductive filler (B1) include alumina, aluminum nitride, magnesium oxide, calcium fluoride, glass beads, and hexagonal boron nitride aggregated in a spherical shape or a granular shape. However, magnesium oxide is preferable in terms of low Mohs hardness, thermal conductivity, and cost. Magnesium oxide preferably has a water absorption rate of 0.5% or less, and more preferably 0.3% or less. If it exceeds 0.5%, the resin may be hydrolyzed when blended with the resin, or fired during molding. For example, the water absorption can be reduced to 0.5% or less by baking magnesium oxide at a high temperature of 1900 ° C. or higher, or by surface treatment with a silane coupling agent or the like. Here, the water absorption is a mass change rate when treated for 48 hours in an atmosphere of a temperature of 85 ° C. and a relative humidity of 85%.

  The resin composition in the present invention is characterized by containing at least one reinforcing material (C) selected from the group consisting of a fibrous filler and an acicular filler. Thereby, the strength and heat resistance of the molded product obtained from the resin composition can be increased. Examples of the fibrous filler include glass fiber, carbon fiber, boron fiber, aramid fiber, and liquid crystal polyester fiber. Examples of the needle-shaped filler include wollastonite (calcium metasilicate). Potassium titanate whisker, aluminum borate whisker, zinc oxide whisker, calcium carbonate whisker and the like. Among these, as the reinforcing material (C), it is preferable to use glass fiber from the viewpoint of high strength and low cost, and from the viewpoint of obtaining a molded product having high surface smoothness, it is preferable to use an acicular filler. preferable. In particular, glass fiber, wollastonite (calcium metasilicate), potassium titanate whisker, and aluminum borate whisker can be preferably used from the viewpoint of maintaining whiteness.

  Such a reinforcing material (C) is a silane coupling agent and / or in order to increase the dispersibility in the thermoplastic resin (A) or to improve the adhesion to the thermoplastic resin (A). It is preferable that the surface treatment is performed with an acrylic resin, a urethane resin, an epoxy resin, or the like.

  The content of the reinforcing material (C) in the resin composition in the present invention is 10 to 100 parts by weight, preferably 15 to 80 parts by weight, more preferably 20 to 60 parts by weight based on 100 parts by weight of the thermoplastic resin (A). Within the range of parts by weight. When the amount is less than 10 parts by weight, the mechanical strength and long-term heat resistance of the molded article made of the resin composition of the present invention are lowered, and when it exceeds 100 parts by weight, the moldability is lowered.

It is preferable that the heat conductive resin composition in this invention further contains 5-100 weight part flame retardant (D). The flame retardancy of the thermoplastic resin composition may be a condition adopted in electric / electronic devices that handle a large current that is equivalent to V-0 in the UL-94 standard.
As a usage-amount of a flame retardant (D), it is more preferable that it is 7-80 weight part, It is more preferable that it is 10-60 weight part, It is further more preferable that it is 12-40 weight part. Various flame retardants (D) are known, and examples include various ones described in “Technology and Application of Polymer Flame Retardation” (P149-221) issued by CMC Chemical. However, it is not limited to these. Among these flame retardants, phosphorus flame retardants, halogen flame retardants, and inorganic flame retardants can be preferably used.

  Examples of phosphorus flame retardants include phosphate esters, halogen-containing phosphate esters, condensed phosphate esters, polyphosphates, and red phosphorus. These phosphorus flame retardants may be used alone or in combination of two or more. Specific examples of the halogen flame retardant include brominated polystyrene, brominated polyphenylene ether, brominated bisphenol type epoxy polymer, brominated styrene maleic anhydride polymer, brominated epoxy resin, brominated phenoxy resin, deca Brominated diphenyl ether, decabromobiphenyl, brominated polycarbonate, perchlorocyclopentadecane, brominated crosslinked aromatic polymer, particularly brominated polystyrene and brominated polyphenylene ether are preferred. These halogen flame retardants may be used alone or in combination of two or more. In addition, the halogen element content of these halogen flame retardants is preferably 15 to 87%.

  Specific examples of the inorganic flame retardant include aluminum hydroxide, antimony trioxide, antimony pentoxide, sodium antimonate, tin oxide, zinc oxide, iron oxide, magnesium hydroxide, calcium hydroxide, zinc borate, Examples include kaolin clay and calcium carbonate. These inorganic compounds may be treated with a silane coupler, a titanium coupler, or the like, or may be used alone or in combination of two or more.

  The thermally conductive resin composition in the present invention further contains 20 to 200 parts by weight of a plate-like thermally conductive filler (B2), and the content ratio with the spherical or granular thermally conductive filler (B1) is a volume ratio. It is preferable that (B1) / (B2) = 5/95 to 70/30. In order to efficiently increase the thermal conductivity in the thickness direction of the thermally conductive resin composition, the content of the thermally conductive filler (B2) is preferably 30 to 180 parts by weight, more preferably 40 to 160 parts by weight. More preferably, it is 50-140 weight part, Most preferably, it is 60-120 weight part. When the ratio of the spherical or granular thermally conductive filler (B1) is less than (B1) / (B2) = 5/95 in volume ratio, the plate-like thermally conductive filler is easily oriented in the in-plane direction. In addition, even if the total amount of the thermally conductive filler is increased, the thermal conductivity in the thickness direction may not be increased. When the ratio of the spherical or granular heat conductive filler (B1) is more than (B1) / (B2) = 70/30, the total amount of the heat conductive filler is set to increase the thermal conductivity in the thickness direction. Need to increase. When the thermally conductive fillers (B1) and (B2) are used under the conditions of (B1) / (B2) = 5/95 to 70/30, the heat conductivity of a spherical or granular material having a relatively high Mohs hardness is obtained. Since the thermal conductivity in the thickness direction can be increased while suppressing the total amount of the filler (B1), the moldability of the resin composition can be further improved. A more preferable volume ratio is (B1) / (B2) = 10/90 to 65/35, and further preferably (B1) / (B2) = 20/80 to 660/40.

  Examples of the plate-like thermally conductive filler (B2) include talc, mica, hexagonal boron nitride, and alumina. The effect of improving the thermal conductivity when blended with a resin and the molding of the resin composition are included. Hexagonal boron nitride is preferable because it is difficult to lower the workability, and talc is preferable from the viewpoint of improving thermal conductivity to some extent and cost.

  The average particle diameter of the heat conductive filler (B2) is preferably 10 μm to 300 μm, more preferably 20 μm to 150 μm, and particularly preferably 30 μm to 60 μm. When the thickness is less than 10 μm, the thermal conductivity of the insulating case may be insufficient, and when it exceeds 300 μm, the moldability may be deteriorated.

The thermoplastic resin composition of the present invention may have long-term heat resistance such that the bending strength retention is 85% or more after heat treatment at 150 ° C. for 2000 hours in an air atmosphere. Thereby, it can be applied not only to the insulating case but also to other uses requiring long-term heat resistance of 150 ° C. 150 ° C. is close to the maximum temperature of electric / electronic devices that handle large currents, and “150 ° C. long-term heat resistance” is a widely adopted condition for electric / electronic devices.
The dielectric breakdown strength of the insulating case of the present invention is preferably 15 kV / mm or more, more preferably 20 kV / mm or more, and further preferably 25 kV / mm or more. If it is less than 15 kV / mm, it may be impossible to use in electric / electronic devices that handle a large current.

The thermoplastic resin in the present invention preferably has a main chain structure composed mainly of repeating units represented by the general formula (1).
-M-Sp- . . . (1)
(In the formula, M represents a mesogenic group, and Sp represents a spacer.)
Here, mainly means that the amount of the general formula (1) contained in the main chain of the molecular chain is 50 mol% or more, preferably 70 mol% or more, more preferably 90 mol% or more, based on all the structural units. And most preferably substantially 100 mol%. If it is less than 50 mol%, high thermal conductivity may not be exhibited due to disorder of the molecular structure, or smectic liquid crystallinity may not be exhibited.

The mesogenic group M contained in the thermoplastic resin of the present invention means a rigid and highly oriented substituent. The mesogenic group M corresponds to the general formula (4) in the following general formula (2) and can be preferably applied.
_{^{-A 1 -x-A 2 -OCO (}} CH 2) m COO- . . . (2)
-A ^{1 -x-A 2} -. . . (4)
(In the formula, A ¹ and A ² each independently represent a substituent selected from an aromatic group, a condensed aromatic group, an alicyclic group, and an alicyclic heterocyclic group. Bond, —O—, —S—, —CH ₂ —CH ₂ —, —C═C—, —C═C (Me) —, —C≡C—, —CO—O—, —CO—NH—. , —CH═N—, —CH═N—N═CH—, —N═N— or —N (O) ═N—, wherein m represents 2 to 20. Indicates an integer.)
Here, A ¹ and A ² each independently represent a hydrocarbon group having a benzene ring having 6 to 12 carbon atoms, a hydrocarbon group having a naphthalene ring having 10 to 20 carbon atoms, or a biphenyl structure having 12 to 24 carbon atoms. A hydrocarbon group having 3 or more benzene rings having 12 to 36 carbon atoms, a hydrocarbon group having a condensed aromatic group having 12 to 36 carbon atoms, and an alicyclic heterocyclic group having 4 to 36 carbon atoms It is preferable that it is selected from.

Specific examples of A ¹ and A ² include phenylene, biphenylene, naphthylene, anthracenylene, cyclohexyl, pyridyl, pyrimidyl, thiophenylene, and the like. These may be unsubstituted or may be a derivative having a substituent such as an aliphatic hydrocarbon group, a halogen group, a cyano group, or a nitro group. x is a bond, direct bond, —CH ₂ —, —C (CH ₃ ) ₂ —, —O—, —S—, —CH ₂ —CH ₂ —, —C═C—, —C≡C —, —CO—, —CO—O—, —CO—NH—, —CH═N—, —CH═N—N═CH—, —N═N— or —N (O) ═N—. A divalent substituent selected from Among these, those in which the number of atoms in the main chain of x corresponding to the connector is an even number are preferable. That is, a direct bond, —CH ₂ —CH ₂ —, —C═C—, —C≡C—, —CO—O—, —CO—NH—, —CH═N—, —CH═N—N═CH A divalent substituent selected from the group of-, -N = N- or -N (O) = N- is preferred. When the number of atoms in the main chain of x is an odd number, the increase in molecular width of the mesogenic group and the flexibility due to the increase in the degree of freedom of rotation of the bond promotes a decrease in the crystallization rate, thereby reducing the thermal conductivity of the resin alone. May decrease.

  Specific examples of such preferred mesogenic groups include biphenyl, terphenyl, quarterphenyl, stilbene, diphenyl ether, 1,2-diphenylethylene, diphenylacetylene, benzophenone, phenylbenzoate, phenylbenzamide, azobenzene, azoxybenzene, 2-naphthoate. , Phenyl-2-naphthoate, and derivatives thereof, and the like, but divalent groups having a structure in which two hydrogens are removed are not limited thereto.

  More preferably, it is a mesogenic group represented by the following general formula (3). This mesogenic group is rigid and highly oriented due to its structure, and is easily available or synthesized.

(In the formula, X is independently an aliphatic hydrocarbon group, F, Cl, Br, I, CN, or NO ₂ , y is an integer of 2 to 4, and n is an integer of 0 to 4.)
In order to obtain a thermoplastic resin composition having excellent moldability, the mesogenic group contained in the thermoplastic resin preferably does not contain a crosslinkable substituent.

The spacer Sp included in the thermoplastic resin means a flexible molecular chain and includes a bonding group with a mesogenic group. The number of main chain atoms of the spacer of the thermoplastic resin is preferably 4 to 28, more preferably 6 to 24, and still more preferably 8 to 20. When the number of main chain atoms of the spacer is less than 4, sufficient flexibility is not expressed in the molecular structure of the thermoplastic resin, the crystallinity may be lowered, and the thermal conductivity may be lowered. Crystallinity may decrease and thermal conductivity may decrease. The type of atoms constituting the main chain of the spacer is not particularly limited, and any type can be used. However, it is preferably at least one atom selected from C, H, O, S, and N.
The spacer Sp corresponds to the general formula (5) in the following general formula (2), and can be preferably applied.
_{^{-A 1 -x-A 2 -OCO (}} CH 2) m COO- . . . (2)
-OCO _{(CH 2)} m COO-. . . (5)
(In the formula, A ¹ and A ² each independently represent a substituent selected from an aromatic group, a condensed aromatic group, an alicyclic group, and an alicyclic heterocyclic group. Bond, —O—, —S—, —CH ₂ —CH ₂ —, —C═C—, —C═C (Me) —, —C≡C—, —CO—O—, —CO—NH—. , —CH═N—, —CH═N—N═CH—, —N═N— or —N (O) ═N—, wherein m represents 2 to 20. Indicates an integer.)
m is preferably an integer of 2 to 20, and more preferably an integer of 4 to 14. M is preferably an even number. In the case of an odd number, since the mesogenic group is inclined, the crystallinity may be lowered and the thermal conductivity may be lowered. In particular, m is preferably at least one selected from 8, 10, and 12 from the viewpoint that a resin having excellent thermal conductivity can be obtained.

  The number average molecular weight of the present invention is high-temperature GPC using a solution prepared by dissolving polystyrene in a mixed solvent of p-chlorophenol and toluene at a volume ratio of 3: 8 so as to have a concentration of 0.25% by weight. (Viscotek: 350 HT-GPC System) is a value measured at a column temperature of 80 ° C. and a detector as a differential refractometer (RI).

  The number average molecular weight of the thermoplastic resin in the present invention is preferably 3000 to 40000, more preferably 3000 to 30000, and particularly preferably 3000 to 20000 in view of the upper limit. On the other hand, considering the lower limit, it is preferably 3000 to 40000, more preferably 5000 to 40000, and particularly preferably 7000 to 40000. Furthermore, when an upper limit and a lower limit are considered, it is more preferable that it is 5000-30000, and it is most preferable that it is 7000-20000. When the number average molecular weight is less than 3000, the mechanical strength as a molded product may be low, and when it is greater than 40000, the molding fluidity may be reduced or the thermal conductivity may be reduced.

  In the thermoplastic resin of the present invention, it is preferable that 10% or more of the end groups of the molecular chain are sealed with an end-capping agent, more preferably 60% or more are sealed, and 80% or more. Is more preferably sealed, particularly preferably 100% sealed. When the end-capping rate is 10% or more, the long-term heat resistance is more excellent, and the molecular weight change during heating is further suppressed.

The end-capping rate of the thermoplastic resin can be obtained by the following formula (6) by measuring the number of end functional groups sealed and unsealed in the thermoplastic resin. The number of each terminal group is preferably determined from the integral value of the characteristic signal corresponding to each terminal group by ¹ H-NMR in terms of accuracy and simplicity.
Terminal sealing rate (%) = [number of sealed terminal functional groups] / ([number of sealed terminal functional groups] + [number of unsealed terminal functional groups]). . . (6)

  As the end-capping agent, a monoamine having 1 to 20 carbon atoms or an aliphatic monocarboxylic acid is preferable from the viewpoint of enhancing the thermal conductivity of the base resin, and an aliphatic monocarboxylic acid having 1 to 20 carbon atoms is more preferable. An aliphatic monocarboxylic acid of several 10 to 20 is more preferable. Specific examples of aliphatic monocarboxylic acids include fatty acids such as acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, and isobutyric acid. Group monocarboxylic acids, and any mixtures thereof. Among these, myristic acid, palmitic acid, and stearic acid are preferable from the viewpoint of particularly improving the thermal conductivity of the base resin. Specific examples of monoamines include aliphatic monoamines such as methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, and any of these A mixture etc. can be mentioned. Among these, butylamine, hexylamine, octylamine, decylamine, stearylamine, and cyclohexylamine are preferable from the viewpoints of reactivity, high boiling point, stability of the capped end, and price.

  The thermoplastic resin in the present invention may be produced by any known method. From the viewpoint that the control of the structure is simple, a method of producing by reacting a compound having reactive functional groups at both ends of the mesogenic group and a compound having reactive functional groups at both ends of the spacer is preferable. As such a reactive functional group, known groups such as a hydroxyl group, a carboxyl group, an alkoxy group, an amino group, a vinyl group, an epoxy group, and a cyano group can be used, and the conditions for reacting these are not particularly limited. From the viewpoint of ease of synthesis, a compound having a hydroxyl group at both ends of the mesogen group and a compound having a carboxyl group at both ends of the spacer, or a compound having a carboxyl group at both ends of the mesogen group and a hydroxyl group at both ends of the spacer Preferred is a production method in which a compound having a reaction is made.

  As an example of a method for producing a thermoplastic resin comprising a compound having a hydroxyl group at both ends of a mesogenic group and a compound having a carboxyl group at both ends of a spacer, a mesogenic group having a hydroxyl group at both ends is substituted with a lower fatty acid such as acetic anhydride. Examples thereof include a method in which an acetate ester is individually or collectively used, and then subjected to a deacetic acid polycondensation reaction with a compound having a carboxyl group at both ends of the spacer in another reaction tank or the same reaction tank. The polycondensation reaction is carried out at a temperature of generally 230 to 350 ° C., preferably 250 to 330 ° C. in the presence of an inert gas such as nitrogen, at normal pressure or under reduced pressure, in the presence of substantially no solvent. ~ 5h done. When the reaction temperature is lower than 230 ° C., the reaction proceeds slowly, and when it is higher than 350 ° C., side reactions such as decomposition tend to occur. When making it react under reduced pressure, it is preferable to raise a pressure reduction degree in steps. When the pressure is rapidly reduced to a high degree of vacuum, the monomer volatilizes and the molecular weight may not be controlled. The ultimate vacuum is preferably 50 torr or less, more preferably 30 torr or less, and particularly preferably 10 torr or less. When the degree of vacuum is greater than 50 torr, the polymerization reaction may take a long time. A multi-stage reaction temperature may be employed. In some cases, the reaction product can be withdrawn in a molten state and recovered as soon as the temperature rises or when the maximum temperature is reached. The obtained thermoplastic resin may be used as it is, or it may be subjected to solid phase polymerization in order to remove unreacted raw materials or improve physical properties. In the case of performing solid phase polymerization, the obtained thermoplastic resin is mechanically pulverized into particles having a particle size of 3 mm or less, preferably 1 mm or less, and an inert gas such as nitrogen at 100 to 350 ° C. in the solid state. It is preferable to perform the treatment for 1 to 20 hours under an atmosphere or under reduced pressure. If the particle size of the polymer particles is 3 mm or more, the treatment is not sufficient, and problems with physical properties are caused, which is not preferable. It is preferable to select the treatment temperature and the rate of temperature increase during solid phase polymerization so that the thermoplastic resin particles do not cause fusion.

  Examples of the acid anhydride of the lower fatty acid used in the production of the thermoplastic resin in the present invention include acid anhydrides of lower fatty acids having 2 to 5 carbon atoms, such as acetic anhydride, propionic anhydride, monochloroacetic anhydride, dichloroacetic anhydride, Examples include trichloroacetic anhydride, monobromoacetic anhydride, dibromoacetic anhydride, tribromoacetic anhydride, monofluoroacetic anhydride, difluoroacetic anhydride, trifluoroacetic anhydride, butyric anhydride, isobutyric anhydride, valeric anhydride, pivalic anhydride, etc. Acetic anhydride, propionic anhydride, and trichloroacetic anhydride are particularly preferably used. The amount of the lower anhydride fatty acid used is 1.01 to 1.50 times equivalent, preferably 1.02 to 1.20 times equivalent to the total of hydroxyl groups of the mesogenic groups used.

  The thermoplastic resin of the present invention may be copolymerized with other monomers to such an extent that the effect is not lost. For example, aromatic hydroxycarboxylic acids, aromatic dicarboxylic acids, aromatic diols, aromatic hydroxyamines, aromatic diamines, aromatic aminocarboxylic acids or caprolactams, caprolactones, aliphatic dicarboxylic acids, aliphatic diols, aliphatic diamines, Examples include alicyclic dicarboxylic acids, and alicyclic diols, aromatic mercaptocarboxylic acids, aromatic dithiols, and aromatic mercaptophenols.

  Specific examples of the aromatic hydroxycarboxylic acid include 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 2-hydroxybenzoic acid, 2-hydroxy-6-naphthoic acid, 2-hydroxy-5-naphthoic acid, 2-hydroxy 7-naphthoic acid, 2-hydroxy-3-naphthoic acid, 4'-hydroxyphenyl-4-benzoic acid, 3'-hydroxyphenyl-4-benzoic acid, 4'-hydroxyphenyl-3-benzoic acid and their Examples thereof include alkyl, alkoxy, and halogen-substituted products.

  Specific examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 4,4′-dicarboxybiphenyl, 3 , 4′-dicarboxybiphenyl, 4,4 ″ -dicarboxyterphenyl, bis (4-carboxyphenyl) ether, bis (4-carboxyphenoxy) butane, bis (4-carboxyphenyl) ethane, bis (3- Carboxyphenyl) ether and bis (3-carboxyphenyl) ethane and the like, alkyl, alkoxy or halogen substituted products thereof.

Specific examples of the aromatic diol include, for example, pyrocatechol, hydroquinone, resorcin, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 3,3′-dihydroxybiphenyl, 3,4 ′. -Dihydroxybiphenyl, 4,4'-dihydroxybiphenyl, 4,4'-dihydroxybiphenol ether, bis (4-hydroxyphenyl) ethane, 2,2'-dihydroxybinaphthyl, etc., and alkyl, alkoxy or halogen substituted products thereof Is mentioned.
Specific examples of the aromatic hydroxyamine include 4-aminophenol, N-methyl-4-aminophenol, 3-aminophenol, 3-methyl-4-aminophenol, 4-amino-1-naphthol, 4-amino- 4'-hydroxybiphenyl, 4-amino-4'-hydroxybiphenyl ether, 4-amino-4'-hydroxybiphenylmethane, 4-amino-4'-hydroxybiphenyl sulfide and 2,2'-diaminobinaphthyl and their alkyls , Alkoxy or halogen-substituted products.

  Specific examples of the aromatic diamine and aromatic aminocarboxylic acid include 1,4-phenylenediamine, 1,3-phenylenediamine, N-methyl-1,4-phenylenediamine, N, N′-dimethyl-1,4. -Phenylenediamine, 4,4'-diaminophenyl sulfide (thiodianiline), 4,4'-diaminobiphenyl sulfone, 2,5-diaminotoluene, 4,4'-ethylenedianiline, 4,4'-diaminobiphenoxyethane 4,4′-diaminobiphenylmethane (methylenedianiline), 4,4′-diaminobiphenyl ether (oxydianiline), 4-aminobenzoic acid, 3-aminobenzoic acid, 6-amino-2-naphthoic acid and 7-amino-2-naphthoic acid and alkyl, alkoxy or halogen substituted products thereof It is below.

  Specific examples of the aliphatic dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, fumaric acid, maleic acid Etc.

  Specific examples of the aliphatic diamine include 1,2-ethylenediamine, 1,3-trimethylenediamine, 1,4-tetramethylenediamine, 1,6-hexamethylenediamine, 1,8-octanediamine, 1,9- Nonanediamine, 1,10-decanediamine, 1,12-dodecanediamine, and the like can be given.

  Specific examples of the alicyclic dicarboxylic acid, aliphatic diol and alicyclic diol include hexahydroterephthalic acid, trans-1,4-cyclohexanediol, cis-1,4-cyclohexanediol, and trans-1,4-cyclohexane. Dimethanol, cis-1,4-cyclohexanedimethanol, trans-1,3-cyclohexanediol, cis-1,2-cyclohexanediol, trans-1,3-cyclohexanedimethanol, ethylene glycol, propylene glycol, butylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol, neo Such as pentyl glycol Such Jo or branched chain aliphatic diols, as well as reactive derivatives thereof.

  Specific examples of the aromatic mercaptocarboxylic acid, aromatic dithiol and aromatic mercaptophenol include 4-mercaptobenzoic acid, 2-mercapto-6-naphthoic acid, 2-mercapto-7-naphthoic acid, benzene-1,4- Dithiol, benzene-1,3-dithiol, 2,6-naphthalene-dithiol, 2,7-naphthalene-dithiol, 4-mercaptophenol, 3-mercaptophenol, 6-mercapto-2-hydroxynaphthalene, 7-mercapto-2 -Hydroxynaphthalene and the like, as well as reactive derivatives thereof.

  The thermoplastic resin composition of the present invention includes an epoxy resin, a polyolefin resin, a bismaleimide resin, a polyimide resin, a polyether resin, a phenol resin, a silicone resin, a polycarbonate resin, and a polyamide as long as the effects of the present invention are not lost. Any known resin such as resin, polyester resin, fluorine resin, acrylic resin, melamine resin, urea resin, urethane resin may be contained. Specific examples of preferred resins include polycarbonate, polyethylene terephthalate, polybutylene terephthalate, liquid crystal polymer, nylon 6, nylon 6,6 and the like. The amount of these resins used is preferably in the range of 0 to 10000 parts by weight and more preferably in the range of 1 to 800 parts by weight with respect to 100 parts by weight of the thermoplastic resin usually contained in the thermoplastic resin molding. preferable.

  In the thermoplastic resin composition of the present invention, as an additive other than the resin and the filler, any other components such as a reinforcing agent, a thickener, a release agent, a coupling agent, a difficulty agent, and the like, depending on the purpose. A flame retardant, a flame retardant, a pigment, a colorant, other auxiliary agents, and the like can be added as long as the effects of the present invention are not lost. The amount of these additives used is preferably in the range of 0 to 20 parts by weight and more preferably in the range of 0.1 to 15 parts by weight with respect to 100 parts by weight of the thermoplastic resin.

It does not specifically limit as a compounding method of the compound with respect to a thermoplastic resin. For example, it can be produced by drying the above-described components, additives and the like and then melt-kneading them in a melt-kneader such as a single-screw or twin-screw extruder. Moreover, when a compounding component is a liquid, it can also manufacture by adding to a melt-kneader on the way using a liquid supply pump etc.
The insulating case of the present invention can be molded by various resin molding methods such as injection molding, extrusion molding, press molding, and blow molding. Among these molding methods, an injection molding method is preferable because it is simple. The injection molding is a molding method in which a mold is attached to an injection molding machine, a resin composition melt-plasticized by the molding machine is injected into the mold at a high speed, and the resin composition is cooled and solidified to be taken out. Specifically, the thermoplastic resin in the present invention is heated to a smectic liquid crystal state and injected into a mold. Molding cannot be performed at a temperature lower than T _{s, and at} a temperature equal to or higher than T _i , the resin melts isotropically, so that the thermal conductivity may decrease. Here, from the viewpoint of molding fluidity, the mold temperature is preferably T _s -100 ° C or higher, more preferably T _s -80 ° C or higher, and further T _s -50 ° C or higher. preferable.

  The insulating case of the present invention has high thermal conductivity in the thickness direction and long-term heat resistance of 150 ° C. Further, the resin composition constituting the insulating case does not require a large amount of heat conductive filler for the purpose of achieving high heat conductivity, and thus has a low specific gravity and good molding fluidity. Such insulation cases are used for encapsulating resin for bus bars in electrical and electronic devices that handle large currents such as generators, motors, transformers, current transformers, voltage regulators, rectifiers, inverters, and chargers, especially power modules. In addition, it can be suitably used as an insulating case that houses a bus bar and a coil and secures insulation between the bus bar and the coil.

  Next, the insulating case of the present invention will be described in more detail with reference to production examples, examples and comparative examples, but the present invention is not limited to such examples. Unless otherwise specified, the reagents listed below were used without purification from Wako Pure Chemical Industries.

  The raw material components used for preparing the resin composition are shown below.

[Other resins]
・ Polyethylene terephthalate resin (PET):
Novapex PBKII manufactured by Mitsubishi Chemical Corporation
-Polybutylene terephthalate (PBT):
NOVADURAN 5008L manufactured by Mitsubishi Engineering Plastics Co., Ltd.
-Nematic liquid crystal polymer (UENOLCP):
UENOLCP A-2100 manufactured by Ueno Pharmaceutical Co., Ltd.

[Spherical or granular thermally conductive filler (B1)]
Magnesium oxide (MgO):
RF-98 (MgO-1, no surface treatment, water absorption 0.5% or less, average particle size 50 μm) and RF-50-SC (MgO-2, no surface treatment, water absorption 0.3) manufactured by Ube Material Co., Ltd. %, Average particle size 50 μm)
Aluminum nitride (AlN):
Toyorunite FLA manufactured by Toyo Aluminum Co., Ltd., average particle size 12μm,

[Plate-like thermally conductive filler (B2)]
Boron nitride powder (BN):
PT110 (BN-1, average particle diameter 45 μm) and PT100 (BN-2, average particle diameter 13 μm) manufactured by Momentive Performance Materials
·talc:
MS-KY manufactured by Nippon Talc Co., Ltd., average particle size 23 μm

[Reinforcing material (C)]
・ Glass fiber (GF):
T187H / PL manufactured by Nippon Electric Glass Co., Ltd., fiber diameter 13 μm, number average fiber length 3.0 mm
・ Wollastonite (WN):
NYGLOS8 manufactured by Sakai Kogyo Co., Ltd., fiber diameter 8 μm, number average fiber length 136 μm

[Flame Retardant (D)]
A mixture of brominated flame retardant and sodium antimonate, BT-Sb:
BT-93 / W: Sb = 23: 6 (weight ratio)
・ EM-Sb:
Emerald 1000: Sb = 17: 8 (weight ratio)
Brominated flame retardant:
-SAYTEX BT-93 / W (BT) manufactured by Albemarle Japan
Emerald1000 (EM) manufactured by Chemtura
・ Sodium antimonate (Sb):
SA-A manufactured by Nippon Seiko Co., Ltd.

[Evaluation method]
Number average molecular weight: A sample was prepared by dissolving the thermoplastic resin used in the present invention in a mixed solvent of p-chlorophenol (manufactured by Tokyo Chemical Industry Co., Ltd.) and toluene in a volume ratio of 3: 8 to a concentration of 0.25% by weight. . The standard material was polystyrene, and a similar sample solution was prepared. The measurement was performed using a high temperature GPC (350 HT-GPC System manufactured by Viscotek) under conditions of a column temperature of 80 ° C. and a flow rate of 1.00 mL / min. A differential refractometer (RI) was used as a detector.

Differential scanning calorimetry (DSC measurement): The temperature is raised and lowered at a rate of 10 ° C./min in the range of 50 ° C. to 320 ° C., and from the peak top of the endothermic peak at the second temperature rise of 10 ° C./min, The transition point (T _s ) from the liquid crystal phase to the liquid crystal phase and the transition point (T _i ) from the liquid crystal phase to the isotropic phase were determined.
Observation with an optical polarizing microscope: The thermoplastic resin (A) was heated to _Ti or higher on a hot stage, and the temperature was lowered to a temperature showing liquid crystal at 10 ° C./min, and the optical structure of the liquid crystal was observed.

Test piece molding conditions: The obtained pellet-shaped resin composition was dried at 120 ° C. for 4 hours using a hot air dryer, and then various test pieces were molded using an injection molding machine. At this time, the cylinder temperature was set to T _s + 30 ° C. of a smectic liquid crystalline thermoplastic resin, the mold temperature was set to 120 to 150 ° C., and injection was performed. However, when the smectic liquid crystalline thermoplastic resin was not used, the cylinder temperature was set to the melting point of the thermoplastic resin used + 30 ° C.

  Thermal conductivity: In a disk-shaped sample having a thickness of 1 mm × 25 mmφ, the thermal conductivity in the in-plane direction of the sample in the room temperature atmosphere was measured with a laser flash method thermal conductivity measuring device (LFA447 manufactured by NETZSCH).

  Specific gravity: Calculated by the Archimedes method using a disk-shaped sample having a thickness of 1 mm × 25 mmφ.

  Formability: Formability was judged as follows from a test by a spiral flow having a thickness of 1 mm. ○: Flow length is 100 mm or more, Δ: Flow length is 50 to 100 mm, X: Flow length is less than 50 mm.

  Long-term heat resistance test: A test piece (4 × 10 × 80 mm) is heat-treated in a drier at 150 ° C. for 2000 hours in air, and the bending strength of the test piece with and without heat treatment is measured in accordance with ISO178. The strength retention was calculated.

  Dielectric strength: measured according to ASTM D149 using a test piece (2 × 100 × 100 mm).

[Production Example 1]
In a closed reactor equipped with a reflux condenser, a thermometer, a nitrogen introduction tube, and a stirring rod, 4,4′-dihydroxybiphenyl, dodecanedioic acid, and acetic anhydride were each in a molar ratio of 1.0: 1.1: 2. .1 was charged, and sodium acetate was used as a catalyst to react at 145 ° C. under normal pressure and nitrogen atmosphere to obtain a uniform solution, and then the temperature was raised to 250 ° C. at 2 ° C./min while acetic acid was distilled off. And stirred at 250 ° C. for 1 hour. Subsequently, while maintaining the temperature, the pressure was reduced to 10 Torr over about 40 minutes, and then the reduced pressure state was maintained. Three hours after the start of pressure reduction, the pressure was returned to normal pressure with nitrogen gas, and the produced polymer was taken out. The number average molecular weight of the obtained resin was 9500, T _S was 205 ° C., T _i was 255 ° C., and the end capping rate was 0%. From the observation with a polarizing microscope, a batnet structure was observed in a liquid crystal state, and it was confirmed that the liquid crystal was a smectic liquid crystal. The obtained resin is (A-1), and the molecular structure is shown in Table 1.

[Production Example 2]
In a closed reactor equipped with a reflux condenser, a thermometer, a nitrogen introduction tube and a stirring rod, 4,4′-dihydroxybiphenyl, tetradecanedioic acid, and acetic anhydride were each in a molar ratio of 0.9: 1.09: 0. The mixture was charged at a ratio of 1: 2.1 and reacted at 145 ° C. under normal pressure and nitrogen atmosphere using sodium acetate as a catalyst to obtain a homogeneous solution, and then 240 ° C. at 2 ° C./min while distilling off acetic acid. The temperature was raised to ° C and stirred at 240 ° C for 30 minutes. Furthermore, it heated up to 260 degreeC at 1 degreeC / min, and stirred at 260 degreeC for 1 hour. Subsequently, while maintaining the temperature, the pressure was reduced to 10 Torr over about 40 minutes, and then the reduced pressure state was maintained. Three hours after the start of pressure reduction, the pressure was returned to normal pressure with nitrogen gas, and the produced polymer was taken out. The number average molecular weight of the resin 10000, _{T S} is 190 ° C., _{T i} is 240 ° C., terminal blocking ratio was 0%. From the observation with a polarizing microscope, a batnet structure was observed in a liquid crystal state, and it was confirmed that the liquid crystal was a smectic liquid crystal. The obtained resin is (A-2), and the molecular structure is shown in Table 1.

[Production Example 3]
In a closed reactor equipped with a reflux condenser, a thermometer, a nitrogen introduction tube and a stirring rod, 4,4′-dihydroxybiphenyl, sebacic acid, catechol, stearic acid, and acetic anhydride were each in a molar ratio of 1: 1.01. : 0.05: 0.08: 2.2 was charged, sodium acetate was used as a catalyst, and the reaction was carried out at 145 ° C. under normal pressure and nitrogen atmosphere to obtain a uniform solution, and then acetic acid was distilled off. The temperature was raised to 240 ° C. at 2 ° C./min and stirred at 240 ° C. for 30 minutes. Furthermore, it heated up to 260 degreeC at 1 degreeC / min, and stirred at 260 degreeC for 1 hour. Subsequently, while maintaining the temperature, the pressure was reduced to 10 Torr over about 40 minutes, and then the reduced pressure state was maintained. Three hours after the start of pressure reduction, the pressure was returned to normal pressure with nitrogen gas, and the produced polymer was taken out. The number average molecular weight of the obtained resin 15000, _{T S} is 210 ° C., _{T i} is 275 ° C., terminal blocking ratio was 99%. From the observation with a polarizing microscope, a batnet structure was observed in a liquid crystal state, and it was confirmed that the liquid crystal was a smectic liquid crystal. The obtained resin is (A-3), and the molecular structure is shown in Table 1.

[Examples 1 to 7 and Comparative Examples 1 to 4]
After the thermoplastic resin (A) shown in Table 1 and other resin materials were dried at 120 ° C. for 4 hours using a hot air dryer, the resin component and various blends in the amounts shown in Table 1 were combined with the thermoplastic resin (A ) In a liquid crystal state, in Comparative Example 1, it was extruded into a strand using a 15 mm co-rotating fully meshed twin screw extruder KZW15-45MG (manufactured by Technobell Co., Ltd.) at 290 ° C., cut by a pelletizer and pellets A thermoplastic resin composition was obtained. Using the obtained resin composition, the above-mentioned various test pieces were produced and various physical properties were evaluated. The results are shown in Table 2 and Table 3.

  As is clear from Tables 1 and 2, the resin compositions of Examples 1 to 7 have a high thermal conductivity of 2.0 W / (m · K) or more in the thickness direction, molding processability, and long-term heat resistance. Excellent dielectric breakdown strength. On the other hand, the resin composition of Comparative Example 1 is derived from the low thermal conductivity of the base resin because the base resin does not exhibit smectic liquid crystallinity, and the thermal conductivity in the thickness direction of the resin composition is 1 Low at 1 W / (m · K). Also, the bending strength retention after the long-term heat resistance test is less than 85%. In the resin composition of Comparative Example 2, since the base resin is a nematic liquid crystalline resin and has a high melting point, the resin composition is excellent in long-term heat resistance, but the thermal conductivity in the thickness direction of the resin composition is low. In the case of the resin composition of Comparative Example 3, since MgO exceeds 250 parts by weight with respect to 100 parts by weight of the thermoplastic resin (A), the molding processability is poor. In the case of the resin composition of Comparative Example 4, the spherical or granular thermal conductive filler (B1) is not contained at all, and only the plate-shaped thermal conductive filler (B2) is used in a large amount. Since this filler is oriented in the in-plane direction by injection molding, the thermal conductivity in the thickness direction is less than 2 W / (m · K). In the case of the resin composition of Comparative Example 5, since the reinforcing material (C) is not contained at all, the bending strength retention after the long-term heat resistance test is less than 85%.

  The insulating case of the present invention has a high thermal conductivity of 2.0 W / (m · K) or more in the thickness direction, and is excellent in molding processability, long-term heat resistance, and dielectric breakdown strength. Therefore, heat generated from bus bars and coils in electrical / electronic devices that handle large currents, such as power converters and chargers used in hybrid vehicles and electric vehicles, is electrically conductive, such as metal heat sinks. It can be suitably used as an insulator for the purpose of efficiently transferring heat to the heat dissipating member and ensuring insulation between the heat generating members or between the heat generating member and the heat dissipating member. This makes it possible to achieve high performance while maintaining the size or size of the electric / electronic device, and thus the industrial advantage is very large.

Claims (14)

  A spherical or granular thermal conductive filler with respect to 100 parts by weight of the thermoplastic resin (A), which exhibits a smectic liquid crystal property upon heating and has a transition point from a crystal phase to a smectic liquid crystal phase of 180 ° C. or higher. Thermally conductive resin composition containing 10 to 100 parts by weight of (B1) at 50 to 250 parts by weight and at least one reinforcing material (C) selected from the group consisting of a fibrous filler and an acicular filler. Insulating case consisting of   The insulating case according to claim 1, wherein the heat conductive resin composition further contains 5 to 100 parts by weight of a flame retardant (D).   The thermally conductive resin composition further contains 20 to 200 parts by weight of a plate-like thermally conductive filler (B2), and the content ratio with the spherical or granular thermally conductive filler (B1) is in a volume ratio ( The insulating case according to claim 1 or 2, wherein B1) / (B2) = 5/95 to 70/30. Spherical or granular thermal-(B1), having a water absorption rate of magnesium oxide 0.5%, the insulation case according to any one of claims 1 to 3.   The insulating case according to claim 3 or 4, wherein the plate-like thermally conductive filler (B2) is at least one selected from talc and hexagonal boron nitride. Reinforcement (C) is glass fiber, wollastonite, insulation case according to claim 1 is at least one selected from the group consisting of potassium titanate whisker and aluminum borate whisker, . The thermal-conductive resin composition is under an air atmosphere, after 2000 hours of heat treatment at 0.99 ° C., flexural der retention over 100% of the strength is, and the thickness direction of the thermal conductivity of 2W / (m · K) or higher insulation case according to any one of claims 1 to 6 der Ru. Insulation case according to any one of the heat backbone structure of the thermoplastic resin, according to claim 7 comprising repeating units of units represented mainly by the general formula (1).
-M-Sp-. . . (1)
(In the formula, M represents a mesogenic group, and Sp represents a spacer.) The insulating case according to claim 8, wherein the thermoplastic resin is mainly composed of repeating units represented by the following general formula (2).
_{^{-A 1 -x-A 2 -OCO (}} CH 2) m COO-. . . (2)
(In the formula, A ¹ and A ² each independently represent a substituent selected from an aromatic group, a condensed aromatic group, an alicyclic group, and an alicyclic heterocyclic group. Bond, —O—, —S—, —CH ₂ —CH ₂ —, —C═C—, —C═C (Me) —, —C≡C—, —CO—O—, —CONH—, — A divalent substituent selected from the group of CH = N-, -CH = N-N = CH-, -N = N- or -N (O) = N-, where m is an integer of 2 to 20. Show.) Wherein the thermoplastic resin -A 1 ^-x-A 2 ^-, wherein the is represented by the following general formula (3), an insulating case of claim 9.

(In the formula, each R is independently an aliphatic hydrocarbon group, F, Cl, Br, I, CN, or NO ₂ , y is an integer of 2 to 4, and n is an integer of 0 to 4.) The insulating case according to claim 9, wherein m of the thermoplastic resin is at least one selected from an even number of 4 to 14. 11 . Is 3,000 to 40,000 number average molecular weight of the thermoplastic resin, the insulation case according to any one of claims 1 to 11. The insulation case of any one of Claims 1-12 in which 10% or more of the terminal groups of the molecular chain of the thermoplastic resin (A) are sealed with a terminal sealing material. Power module formed by using a insulating case according to any one of claims 1 to 13.