JP2012238676A - Resin molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin molded product having a small number of processing steps and assembly steps and having good heat dissipation characteristics.
A part of a metal part 1 is embedded in a resin molding part 3 made of a thermoplastic resin composition, and a heat generating part 5 is connected to a part 1A where the metal part 1 is exposed. The heat generated by the heat generating component 5 is radiated to the heat radiating plate 7 through the metal component 1 and the thermoplastic resin layer 3A constituting a part of the resin molding portion 3. The thickness t of the thermoplastic resin layer 3A is 0.4 to 1 mm.
[Selection] Figure 1

Description

  The present invention relates to a resin molded product having excellent heat dissipation characteristics.

  In recent years, various types of electrical and electronic devices have become more sophisticated, smaller and lighter, and the components are exposed to high temperatures due to the heat generated by the mounted components and surrounding components. There is. In particular, automobile control systems are shifting to a system in which conventional mechanisms that have been mechanically operated are electrically operated and electrically linked to each other, and electronic components are more dispersed and become a heat source. It tends to be placed at a close position. In addition, the demand for higher output (higher voltage, higher current) and smaller size for mounting components themselves has been increasing in the trend of electrification of powertrains, and the amount of generated heat has increased rapidly. ing. Such a trend of high heat generation and high temperature is not limited to in-vehicle devices, and is similarly observed in all electric and electronic devices, and is expected to become more prominent. In order to cope with such a situation, there is an increasing demand for a technique for improving the heat dissipation characteristics of each member constituting the electric / electronic device.

  As a countermeasure, Patent Document 1 discloses a conductive member fastening structure that can enhance heat dissipation characteristics from a conductive member even when a plurality of conductive members are electrically connected via a terminal block. In this technology, a terminal block consisting of a base made of a non-conductive resin and a conductive fixing part (base nut) formed integrally with the base is used, and on one end surface of the fixing part exposed from the base, The first conductive member (first to third cable terminals) and the second conductive member (first to third bus bars) are overlapped and fastened with a conductive fastening member (bolt). Then, the other end surface of the fixing portion exposed from the base is fastened to a metal heat sink via an electrically insulating sheet to enhance the heat dissipation characteristics from the conductive member.

Patent Document 2 discloses a mounting structure of a bus bar to a heat radiating plate that has high thermal conductivity from a high-temperature bus bar to the heat radiating plate and maintains high cooling efficiency without a decrease in thermal conductivity. In this technique, a convex part having a screw hole is formed in a metal heat dissipation plate, and a hole into which the convex part is inserted is formed in a bus bar. And the convex part of a heat radiating plate is inserted in the hole of a bus bar, a bus bar and a heat radiating plate are contact | abutted via an insulating member, and a screw is screwed together and fastened.
On the other hand, thermoplastic resin molded products are used for structural members and the like in many electrical and electronic devices. Since the thermoplastic resin molded product is insulative, the insulating structure of the structural member or the like can be simplified by applying the thermoplastic resin molded product to a structural member or the like that has conventionally used a metal material. . Thereby, the moldability of the structural member and the like is improved, and the cost can be reduced and the weight can be reduced.

  However, the thermal conductivity of the thermoplastic resin molded product is about 0.3 to 0.6 W / m · K, which is very low compared to metal materials and ceramic materials. In addition, from the viewpoint of moldability, the resin layer needs to have a thickness equal to or greater than a predetermined thickness, so that the thermal resistance of the thermoplastic resin molded product is increased, and it is difficult to meet the above requirement for heat dissipation characteristics.

  Therefore, in order to increase the thermal conductivity of the thermoplastic resin molded product, a filler having a higher thermal conductivity than that of the resin is added to achieve higher thermal conductivity and higher heat dissipation. In general, a conductive material such as metal or carbon having a high thermal conductivity is filled. Examples of the insulating filler include talc, silica, alumina, magnesia and the like. The more the substance having high thermal conductivity is filled with the volume fraction, the more the thermal conductivity can be improved. However, by adding these fillers, moldability, mechanical properties, and insulation properties are reduced. In addition, the characteristics and characteristics vary depending on the type of filler, and it is necessary to adjust the combination and blending of fillers according to the purpose.

JP 2008-98007 A JP 2006-217736 A

  However, in the technique described in Patent Document 1, the number of processing steps for the terminal block (integration of the base and the fixing portion) and the number of assembly steps for interposing an electrically insulating sheet between the terminal block and the heat sink increase. There is a problem. In addition, depending on the type of electrically insulating sheet interposed between the terminal block and the heat sink, there is a problem that the heat dissipation characteristics are insufficient.

  Also in the technique described in Patent Document 2, the number of processing steps for forming a convex portion having a screw hole in the heat radiating plate and an insulating member (for example, an insulating sheet or insulating grease) is interposed between the bus bar and the heat radiating plate. There is a problem that the number of assembly steps increases. In addition, depending on the type of insulating member interposed between the bus bar and the heat radiating plate, there is a problem that the heat radiating characteristics become insufficient.

  On the other hand, in the case of a thermoplastic resin molded article, it is desirable to reduce the thickness of the resin layer of the heat radiating portion within a range that can ensure insulation, in consideration of its thermal conductivity. However, when the fluidity of the thermoplastic resin is poor, the reliability is lowered due to insufficient filling of the thin wall portion with the thermoplastic resin or the occurrence of welds. For this reason, the thermoplastic resin is required to have high fluidity as well as thermal conductivity.

  The problem to be solved by the present invention is to provide a resin molded product having a small number of processing steps and assembly steps for imparting heat dissipation properties and good heat dissipation characteristics.

  In the present invention, a part of a metal part is embedded in a resin molded part made of a thermoplastic resin composition, a heat generating part is connected to a part where the metal part is exposed, and heat generated by the heat generating part is transferred to the metal part and the resin. The object of improvement is a resin molded product that radiates heat to the heat sink through a thermoplastic resin layer that constitutes a part of the molded part.

  Here, “partially embedded” includes a state in which a metal part other than a part to which the heat-generating part is connected is covered with a thermoplastic resin and a state in which the metal part is hardly covered with a thermoplastic resin.

  Further, the shape and material of the metal part used in the present invention are not particularly limited. For example, when a metal part has a hollow inner wall, the metal part can be fitted to another part. Moreover, when it has a female screw in a hollow inner wall, a metal component and another component can be fastened and attached using the volt | bolt which has a male screw. Further, if a material having high thermal conductivity is used, the heat dissipation characteristics can be improved. The heat-generating component is not limited to a component that generates heat, such as a heat-generating element, and is a concept that includes a member such as a bus bar connected to the component.

  The heat radiating plate can be made of a metal or alloy having high heat radiating properties such as aluminum or aluminum alloy. Aluminum and aluminum alloys are suitable as a heat sink because they have advantages such as good workability, low cost, resistance to rust, and high thermal conductivity. Further, the shape of the heat sink may be a simple flat plate. However, in order to increase the cooling efficiency, the thickness may be about 4 to 10 mm, and the surface opposite to the surface in contact with the resin insulating layer may be shaped like a cooling fin. . The heat radiation using the heat radiating plate may be performed from the lower surface of the metal part to which the heat generating component is connected, or may be performed from the side surface of the metal part to which the heat generating component is connected.

  In the resin molded product of the present invention, the thickness of the thermoplastic resin layer is 0.4 to 1 mm. Thus, after embedding a part of the metal part in the resin molded part made of the thermoplastic resin composition and connecting the heat-generating part to the part where the metal part is exposed, the thermoplastic resin layer has such a thickness dimension. In this case, sufficient heat dissipation characteristics can be ensured while reducing the number of processing steps and assembly steps for imparting heat dissipation. If a thermoplastic resin having a thermal conductivity in the thickness direction of 1.2 W / m · K or more is used for the thermoplastic resin layer, more sufficient heat dissipation characteristics can be secured.

  The thermoplastic resin preferably contains a matrix resin and boron nitride as an inorganic filler. Here, “average particle size of single particle” means the average particle size of primary particles. Further, the average particle diameter is measured using a known particle size measuring apparatus by laser diffraction / scattering method, and indicates the particle diameter when the cumulative weight obtained by measuring the particle size distribution is 50%. Here, the laser diffraction / scattering method is a measurement method utilizing the fact that the intensity pattern of the scattered light changes depending on the particle diameter when the filler particles are irradiated with laser light.

  Boron nitride preferably has an average particle diameter of 18 μm or more, more preferably a scaly shape. When such boron nitride is used, the contact probability between the inorganic fillers is increased even with the same filling amount, and aggregates of scaly crystals (the shape is spherical or massive) or the average particle size of a single particle Compared with the case of using boron nitride having a diameter of less than 18 μm, the thermal conductivity in the thickness direction can be increased. For this reason, the content of boron nitride for ensuring the desired thermal conductivity can be reduced, and good moldability and mechanical strength can be ensured. In particular, boron nitride having an average particle size of 35 μm or more as a single particle is more preferable because a moldability is good and a resin molded product having a higher thermal conductivity in the resin flow direction during molding can be obtained. In addition, since the thermal conductivity of the resin molded product is improved as the average particle size is larger, the upper limit value of the average particle size is not particularly specified. However, boron nitride having an average particle size exceeding 45 μm is difficult to obtain on the market at this time.

  Content of boron nitride shall be 15-30 volume% with respect to the total volume of matrix resin and an inorganic filler. If the boron nitride content is low, the thermal conductivity of the resin molded product tends to decrease, and if the boron nitride content is high, the moldability (fluidity) and the mechanical strength of the resin molded product tend to decrease. There is. By setting the boron nitride content in the above range, sufficient thermal conductivity and fluidity can be obtained.

  Moreover, it is preferable that content of an inorganic filler shall be 25-50 volume% with respect to the total volume of matrix resin and an inorganic filler. By setting the content of the inorganic filler within the above range, sufficient thermal conductivity and fluidity can be obtained. The content of the inorganic filler refers to the total content of boron nitride and magnesium oxide and alumina described later.

  More preferably, the inorganic filler includes magnesium oxide and / or alumina in addition to boron nitride. Thereby, the anisotropy of the thermal conductivity of the thermoplastic resin molded article can be reduced, and the cost can be reduced. In addition, the shape and particle size of magnesium oxide and alumina are not particularly limited. For example, a general aggregate or spherical shape can be used as magnesium oxide and / or alumina.

  The boron nitride, magnesium oxide, and alumina may be surface-treated with various silane coupling agents, alkoxysilane compounds, silicone oils, titanate coupling agents, and the like.

  The matrix resin is not particularly limited, and for example, a molten liquid crystalline resin or polyarylene sulfide resin that exhibits liquid crystallinity in a molten state can be used. For example, when a molten liquid crystalline resin is used as the matrix resin, the molecular chain is oriented during molding, and a resin molded product having high thermal conductivity can be obtained. The molten liquid crystalline resin has a wholly aromatic polyester skeleton in the main chain, and the higher the ratio of the aromatic polyester in the monomer, the higher the thermal conductivity of the resin molded product. Among them, a molten liquid crystalline resin having a melt viscosity at 290 ° C. of 90 Pa · s or less has good fluidity, a molecular chain is easily oriented during molding, and a resin molded product having higher thermal conductivity can be obtained. In addition, since the moldability of the resin is improved as the melt viscosity is lower, the lower limit value of the melt viscosity at 290 ° C. of the molten liquid crystalline resin is not particularly defined.

As the matrix resin, a polyarylene sulfide resin having a repeating unit represented by the following formula can also be used.

Among the polyarylene sulfide resins, polyphenylene sulfide resins in which the polyarylene group is a phenylene group are preferable. As the phenylene group, one having a structure represented by the following formula can be used. It may be a homopolymer, a copolymer, or a mixture thereof having these configurations.

  In particular, when a polyphenylene sulfide resin having a melt viscosity at 300 ° C. of 170 Pa · s or less is used as the matrix resin, sufficient heat resistance and fluidity can be obtained. In addition, since the moldability of resin improves, so that melt viscosity is low, the lower limit of melt viscosity in 300 degreeC of polyphenylene sulfide resin is not defined in particular.

  Moreover, if the matrix resin to be used has a thermal conductivity of 0.5 W / m · K or more, a resin molded product having a high thermal conductivity and excellent heat dissipation characteristics can be obtained.

  In addition, melt viscosity can be measured as a melt viscosity at the time of extruding from a nozzle on predetermined conditions using a well-known viscosity measuring apparatus.

  In addition to the above, matrix resins that can be used in the present invention include polystyrene, styrene / acrylonitrile copolymer, styrene / maleic anhydride copolymer, (meth) acrylic acid ester / styrene copolymer, and other styrene (co) polymers. Combined; Rubber-reinforced resin such as ABS resin, AES resin, ASA resin, etc .; α-olefin (co) polymer comprising at least one kind of α-olefin having 2 to 10 carbon atoms such as polyethylene, polypropylene, and ethylene / propylene copolymer And olefin resins such as modified polymers (chlorinated polyethylene, etc.) and cyclic olefin copolymers; ethylene copolymers such as ionomers, ethylene / vinyl acetate copolymers, ethylene / vinyl alcohol copolymers; Vinyl, ethylene / vinyl chloride polymer, polyvinylidene chloride and other salts Vinyl-based resins; acrylic resins such as (co) polymers using one or more (meth) acrylic esters such as polymethyl methacrylate (PMMA); polyamide 6, polyamide 6,6, polyamide 6,12 Polyamide resins (PA) such as; Polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate; Polyacetal resin (POM); Polycarbonate resin (PC); Polyarylate resin; Ether; Fluororesin such as polytetrafluoroethylene and polyvinylidene fluoride; Imide resin such as polyimide, polyamideimide, and polyetherimide; Polyetherketone, polyetherketone-based ketone resin; Sulfone such as polysulfone and polyethersulfone System resins; urethane resins; polyvinyl acetate; polyethylene oxide, polyvinyl alcohol, polyvinyl ethers, polyvinyl butyral, phenoxy resin, photosensitive resin; resin such as biodegradable plastics. These can be used in combination of two or more. Among these, rubber reinforced resins, polycarbonate resins and alloys thereof, olefin resins, polyamide resins and polyester resins are preferable.

  In the resin molded product of the present invention, inexpensive inorganic fillers such as talc and calcium carbonate and insulating inorganic fibers may be blended without departing from the object of the present invention. For example, an alumina fiber is preferable because a resin molded product having high mechanical strength and high thermal conductivity in the resin flow direction during molding can be obtained. The insulating inorganic fiber has a fiber diameter of 0.5 to 5 μm and a fiber length of 5 to 500 μm, for example. The insulating inorganic fiber may be surface-treated with various silane coupling agents, alkoxysilane compounds, silicone oils, titanate coupling agents and the like.

  The resin molded product according to the present invention is formed by molding the above thermoplastic resin composition, and is not particularly limited in its use. For example, a housing, an electric / electronic device component having a heat dissipation function, etc. Can be used. Examples of the molding method include injection molding, transfer molding, and compression molding.

  According to the present invention, a part of a metal part is embedded in a resin molded part made of a thermoplastic resin composition, and a heat-generating part is connected to a part where the metal part is exposed, thereby generating heat generated by the heat-generating part. When heat is dissipated to the heat sink through the thermoplastic resin layer that constitutes a part of the metal part and the resin molded part, if the thickness of the thermoplastic resin layer is 0.4 to 1 mm, processing for imparting heat dissipation Man-hours and assembly man-hours are reduced, and sufficient heat dissipation characteristics can be ensured.

It is sectional drawing which shows an example of the resin molded product which concerns on this invention. It is sectional drawing which shows another example of the resin molded product which concerns on this invention. It is sectional drawing which shows another example of the resin molded product which concerns on this invention. It is sectional drawing which shows another example of the resin molded product which concerns on this invention.

  Hereinafter, embodiments of the resin molded product of the present invention will be described. First, in the first embodiment, as shown in FIG. 1, a part of a metal part 1 is embedded in a resin molding part 3 made of a thermoplastic resin composition, and a part 1A where the metal part 1 is exposed is exposed. The heat generating component 5 is connected. Then, the heat generated by the heat generating component 5 is radiated to the heat radiating plate 7 through the metal component 1 and the thermoplastic resin layer 3 </ b> A constituting a part of the resin molding portion 3. In this example, the thickness (indicated by “t” in FIG. 1) of the thermoplastic resin layer 3A is 0.4 to 1 mm. At this time, the thermal conductivity in the thickness direction is 1.2 W / m · K or more. Thus, by setting the thickness of the thermoplastic resin layer 3A to 0.4 to 1 mm, the number of processing steps and assembly steps for imparting heat dissipation can be reduced, and sufficient heat dissipation characteristics can be ensured. .

  In the first embodiment shown in FIG. 1, heat is radiated from the lower surface of the metal component 1 to which the heat generating component 5 is connected. However, as in the second embodiment described later, the heat generating component 105 is connected. It is also possible to dissipate heat from the side surface of the metal part 101 to the heat radiating plate 107 via the thermoplastic resin layer 103A (see FIG. 2).

  Further, in the first embodiment shown in FIG. 1, portions other than the portion to which the heat generating component 5 of the metal component 1 is connected are exposed, but the heat generation of the metal component 201 is performed as in the third embodiment. The part other than the part to which the part 205 is connected may be covered with the resin molding part 203 (see FIG. 3), and most of the metal part 301 is exposed as in the fourth embodiment. It is also possible (see FIG. 4).

  In the second to fourth embodiments shown in FIG. 2 to FIG. 4, the parts common to the first embodiment shown in FIG. , 300 is added and the description is omitted.

  Examples according to the resin molded product of the present invention will be described below. In this example, the following materials were used. In this example, the melt viscosity is measured using a flow tester CFT-500A type manufactured by Shimadzu Corporation, and a resin heated and melted at a predetermined temperature under a load of 0.2 kN, an inner diameter: 2 mm, a length: It is a melt viscosity when extruded from a 10 mm nozzle. The average particle size was measured using a known particle size measuring device by laser diffraction / scattering method (“MICROTRACK SPA-7997” manufactured by Nikkiso Co., Ltd.) and obtained by measuring the particle size distribution. This is the particle diameter when the cumulative weight is 50%.

Matrix resin (a) Molten liquid crystalline resin having a wholly aromatic polyester skeleton in the main chain and exhibiting liquid crystallinity in the molten state: “E7008” (melting point: 275 ° C., melt viscosity at 290 ° C .: 85 Pa · s) )
(B) Melt liquid crystalline resin having a wholly aromatic polyester skeleton in the main chain and exhibiting liquid crystallinity in a molten state: “Ueno LCP5540G” manufactured by Ueno Pharmaceutical (melting point: 293 ° C., melt viscosity at 290 ° C .: 98 Pa · s)
(C) Polyphenylene sulfide resin: “LR-300G” manufactured by DIC (melt viscosity at 300 ° C .: 170 Pa · s)
(D) Polyphenylene sulfide resin: “A503F1” manufactured by Toray (melt viscosity at 300 ° C .: 230 Pa · s)
Inorganic filler (1) Boron nitride: “PT110” manufactured by Momentive Performance Materials Japan (average particle size of single particles: 45 μm, shape: scale-like)
(2) Boron nitride: “SGP” manufactured by Denki Kagaku Kogyo (average particle diameter of single particles: 18 μm, shape: scale-like)
(3) Boron nitride: “HGPE” manufactured by Denki Kagaku Kogyo (average particle size of single particles: 6 μm, shape: scale-like)
(4) Boron nitride: “UHP-EX” manufactured by Showa Denko Co., Ltd. (average particle diameter of aggregate: 50 μm, shape: lump (aggregate of scaly crystals))
(5) Alumina: “AA-3” manufactured by Sumitomo Chemical Co., Ltd. (average particle size of single particles: 3 μm, shape: spherical)
(6) Magnesium oxide: “RF-50-C” manufactured by Ube Industries, Ltd. (average particle size of aggregate: 50 μm, shape: lump (aggregate))
Examples 1-24, Comparative Examples 1-6
After mixing the matrix resin and the inorganic filler with a Henschel mixer, the mixture was melt kneaded (cylinder temperature 260 to 320 ° C.) using a biaxial kneader to produce pellets (resin composition). In addition, the matrix resin and the inorganic filler used the material shown in Tables 1-4 for every Example. Moreover, the compounding of the inorganic filler was adjusted to the amount shown in Tables 1 to 4 for each example.

  The pellet (resin composition) was injection-molded under the conditions of a cylinder temperature of 280 to 340 ° C., a mold temperature of 150 ° C., an injection speed of 80 mm / s, and a holding pressure of 40 MPa to produce a resin molded product.

  In addition, as shown in FIG. 1, the resin molded product in a present Example is a resin molded part 3 in which a part of the metal part 1 (material: copper (C1100), shape: diameter φ15 mm) is made of a thermoplastic resin composition. A heat generating component 5 (thermal resistor) is connected to a portion where the metal component 1 is exposed. Then, heat is radiated from the portion in which the metal part 1 is embedded to the heat radiating plate 7 (aluminum plate, material: 5052, shape: length 200 mm × width 100 mm × height 45 mm) via the thermoplastic resin layer 3A. . At this time, the shape of the resin molding part 3 is 55 mm long × 90 mm wide × 30 mm high. The metal part 1 has a thickness of the thermoplastic resin layer (indicated by “t” in FIG. 1) by adjusting the height of the metal part 1 by setting the protruding height from the resin molded portion 3 to 2 mm. The thickness shown in Tables 1 to 4 is set for each example.

  About the resin molded product in said each Example and a comparative example, thermal conductivity, thermal resistor temperature, bending strength, and withstand voltage property were evaluated. Moreover, the moldability was evaluated about the resin composition. The results are shown in Tables 1-4. Each characteristic shown in the table was evaluated as follows.

  Thermal conductivity: Performed using a flash method apparatus (Xe flash analyzer LFA447 type manufactured by NETZSCH) (according to ASTM E1461). The thermal conductivity was obtained by multiplying the thermal diffusivity measured by the same apparatus by the density measured by Archimedes method and the specific heat measured by DSC method. In addition, thermal conductivity was evaluated about the surface direction and thickness direction of a thermoplastic resin layer.

  Thermal resistor temperature: The heat radiation characteristics were evaluated using the resin molded product shown in FIG. In the resin molded product, a thermoplastic resin layer is pressure-bonded to the heat radiating plate 7 via grease. In addition, water at 40 ° C. constantly flows in the heat sink 7 at a constant flow rate. A power of 15 W was input to the heat generating component 5 (thermal resistor), and the temperature of the thermal resistor 10 minutes after the input was measured.

  Bending strength: A three-point bending strength at room temperature was measured according to JISK7171, using a sample cut out of a resin molded product into a size of 100 mm × 100 mm × thickness 2 mm.

  Voltage resistance: The voltage resistance was evaluated using the resin molded product shown in FIG. In this evaluation, instead of the heat radiating plate 7, an aluminum plate (material: 5052, shape φ30 mm, thickness 0.5 mm) was disposed directly below the metal part 1 with the thermoplastic resin layer interposed therebetween. A voltage of 3.0 kV AC was applied between the metal part 1 and the aluminum plate for 60 seconds, and insulation (leakage current value) was confirmed. The case where insulation was maintained (when the leakage current value was 600 μA or less) was “◯”, and the case where dielectric breakdown occurred (when the leakage current value exceeded 600 μA) was “x”.

Formability: Metal insert molded products were produced, and the formability was judged from the appearance as follows. ○: Injection molding is possible, Δ: Injection molding is possible, but the surface appearance is partially defective, X: Short shot, and injection molding is not possible.

  As is clear from Tables 1 to 4, it can be understood that sufficient heat dissipation characteristics can be secured by setting the thickness of the thermoplastic resin layer to 0.4 to 1 mm (Examples 1 to 12 and Comparative Examples 1 to 3 and Controls of Examples 13-24 and Comparative Examples 4-6). In Examples 1 to 24, the thermal conductivity in the thickness direction is in the range of 1.2 W / m · K or more.

  In Comparative Examples 1 and 4, since the thickness of the thermoplastic resin layer exceeds 1 mm, the heat dissipation characteristics are insufficient and the thermal resistor temperature is high. In Comparative Examples 2 and 5, since the thickness of the thermoplastic resin layer was less than 0.4 mm, the moldability was insufficient. In Comparative Examples 3 and 6, since the thermal conductivity in the thickness direction is less than 1.2 W / m · K, it is considered that the heat dissipation characteristics are insufficient and the temperature of the thermal resistor is increased.

  Boron nitride has a scaly shape and improved thermal conductivity and fluidity when the average particle size of the single particles is 18 μm or more, and further 35 μm or more (Examples 5 and 9 to 11 and Examples). Control of Example 17 and Examples 21-23).

  The matrix resin is a molten liquid crystalline resin having a wholly aromatic polyester skeleton in the main chain and exhibiting liquid crystallinity in a molten state, and has a thermal conductivity when the melt viscosity at 290 ° C. is 90 Pa · s or less. The fluidity was improved (control of Example 5 and Example 12). Further, thermal conductivity and fluidity were improved even when the resin was polyphenylene sulfide resin and the melt viscosity at 300 ° C. was 170 Pa · s or less (contrast of Example 17 and Example 24).

  Thus, in the resin molded product of the present invention, the number of processing steps and assembly steps for imparting heat dissipation are reduced, and sufficient heat dissipation characteristics can be ensured.

  Although the embodiments and examples of the present invention have been specifically described above, the present invention is not limited to these embodiments and examples, and modifications based on the technical idea of the present invention are possible. Of course there is.

DESCRIPTION OF SYMBOLS 1 Metal part 1A Exposed part 3 Resin molding part 3A Thermoplastic resin layer 5 Heat generating part 7 Heat sink

Claims (8)

A part of the metal part is embedded in a resin molding part made of a thermoplastic resin composition, and a heat-generating part is connected to a part where the metal part is exposed, and heat generated by the heat-generating part is transmitted to the metal part. And a resin molded product that radiates heat to the heat sink via a thermoplastic resin layer that constitutes a part of the resin molded portion,
A resin molded product, wherein the thermoplastic resin layer has a thickness of 0.4 to 1 mm.   The resin molded article according to claim 1, wherein the thermoplastic resin layer has a thermal conductivity in the thickness direction of 1.2 W / m · K or more. The thermoplastic resin composition includes a matrix resin and boron nitride having an average particle diameter of 18 μm or more as a single particle as an inorganic filler,
The inorganic filler is 25 to 50% by volume based on the total volume of the matrix resin and the inorganic filler,
3. The resin molded product according to claim 1, wherein the boron nitride is 15 to 30% by volume with respect to a total volume of the matrix resin and the inorganic filler.   The resin molded product according to claim 3, wherein the inorganic filler includes magnesium oxide and / or alumina in addition to boron nitride.   5. The resin molded product according to claim 3, wherein the boron nitride has an average particle size of 35 μm or more as a single particle.   The resin molded product according to any one of claims 3 to 5, wherein the matrix resin is a molten liquid crystalline resin exhibiting liquid crystallinity in a molten state, and has a melt viscosity at 290 ° C of 90 Pa · s or less.   The resin molded product according to any one of claims 3 to 5, wherein the matrix resin is a polyarylene sulfide resin.   The resin molded article according to claim 7, wherein the polyarylene sulfide resin is a polyphenylene sulfide resin and has a melt viscosity at 300 ° C of 170 Pa · s or less.

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