JP2014156100A - Metal-resin integrated molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To propose a metal-resin integrated molding manufactured by two-color injection molding and exhibiting a favorable electromagnetic shieldability over a broad frequency band.SOLUTION: The overall electromagnetic shield characteristic of the provided metal-resin integrated molding 1A is determined by a first electromagnetic shield characteristic ascribed to the metallic material of a metallic molding portion 3, a second electromagnetic shield characteristic ascribed to a first additive 5 mixed with the metallic molding 3 portion, and a third electromagnetic shield characteristic ascribed to a second additive 6 mixed with a resin molding 4 portion. The first and second additives 5 and 6 are mixed respectively with separate molding portions, and since degradations of intrinsic characteristics thereof due to mutual influences can be avoided, an excellent electromagnetic shield characteristic is exhibited over a broad band.

Description

  The present invention relates to an integrally molded product having a structure in which a metal molded part and a resin molded part are integrated by heat fusion, which is manufactured using a two-color injection molding method. In particular, the present invention relates to an integrally molded product of metal and resin suitable for use in parts that require electromagnetic shielding and heat dissipation.

  In in-vehicle components, electronic devices, etc., components such as power semiconductor modules, mounting substrates such as light emitting diodes, IC packages, and the like are required to have electromagnetic shielding properties, heat dissipation properties, and rigidity. Moreover, the predetermined | prescribed decorating property may be requested | required by the outer peripheral surface of such a component.

  Patent Documents 1 and 2 propose a method of manufacturing a composite molded article having a configuration in which a metal layer and a resin layer are integrally formed using a two-color injection molding method. In Patent Document 1, a composite molded article is manufactured using a thermoplastic resin in which an additive having a predetermined electromagnetic wave shielding property is mixed and dispersed, and a metal having a low melting point. A composite molded product having shielding properties is obtained.

Japanese Patent Laid-Open No. 03-140237 JP 2004-223980 A

  In such a composite molded product, there are restrictions on the frequency band where good electromagnetic shielding properties can be obtained, and it is difficult to obtain good electromagnetic shielding properties in the target frequency band or a wider frequency band. There is a problem.

  In the case of adding a shielding filler to the electromagnetic wave shielding resin, for example, carbon is suitable for electromagnetic shielding properties in the 0.1 to 1000 MHz band, and ferrite is suitable for electromagnetic shielding properties in the 30 MHz to 40 GHz band. Therefore, it is conceivable to produce a composite molded article having a wide range of electromagnetic wave shielding properties from the megahertz band to the gigahertz band by blending both fillers in the resin.

  However, when both fillers are blended in the resin, the dispersibility of both fillers in the resin is hindered, and a wide range of electromagnetic shielding properties cannot be obtained, and in both the megahertz band and the gigahertz band. However, sufficient electromagnetic shielding properties cannot be obtained. When the electromagnetic wave passes through the conductive filler in the resin, attenuation due to reflection on the surface and internal absorption is given. It is presumed that the desired electromagnetic shielding properties cannot be obtained because fillers having different characteristics exhibit such a complicated behavior and influence each other.

  As described above, it is not easy to secure a good attenuation characteristic with respect to electromagnetic waves in a wide frequency band over a gigahertz band which is a high frequency band in a conventional molded product of metal and resin.

  In addition, it is difficult for a conventional composite molded product to give high attenuation characteristics to electromagnetic waves in a low frequency band. For this reason, conventionally, an electromagnetic wave shielding sheet is laminated on a composite molded product, or another magnetic shield mechanism is used in combination.

  On the other hand, in the composite molded product, even when the heat dissipation characteristics are improved, a filler or powder made of a heat dissipation material is added to the resin as an additive. In this case, the resin molded portion of the composite molded product is given heat dissipation characteristics as a whole. For this reason, heat radiation and heat insulation cannot be performed partially, and there is a possibility that troubles such as unnecessary heat conduction occur in a portion where heat insulation is required.

  In view of these points, an object of the present invention is to propose an integrally molded metal and resin product having good electromagnetic shielding properties in a wide frequency band from a low band to a high band.

  Another object of the present invention is to propose an integrally molded metal / resin product that has electromagnetic shielding properties over a wide band and has a desired heat dissipation or heat insulation property at a required site.

In order to solve the above problems, the integrally molded product of the metal and resin of the present invention is:
A composite molded body in which the metal molded part and the resin molded part are heat-sealed and integrated by two-color injection molding,
The metal forming part is formed of a metal material in which the first additive is mixed and dispersed,
The resin molded part is formed from a thermoplastic resin material in which a second additive made of a material different from the first additive is mixed and dispersed,
The metal material has a first electromagnetic shielding characteristic;
The first additive has a second electromagnetic shielding characteristic,
The second additive has a third electromagnetic wave shielding characteristic.

  In the integrally molded product of metal and resin of the present invention, the first electromagnetic wave shielding characteristic by the metal material of the metal molding part, the second electromagnetic wave shielding characteristic by the first additive compounded in the metal molding part, and the resin molding part The overall electromagnetic wave shielding characteristics are determined by the third electromagnetic wave shielding characteristics of the second additive added. The first and second additives are blended in separate molded parts, and do not affect each other and deteriorate their own characteristics. Therefore, an integrally molded product having excellent electromagnetic wave shielding characteristics over a wide band can be obtained. In addition, by appropriately selecting the metal material and the first and second additives, an integrally molded product having excellent electromagnetic wave shielding characteristics in a desired band can be obtained.

  Here, a metal or an alloy having a melting point of 250 ° C. or lower is used as the metal material. As the resin material, any one of polycarbonate, ABS, polystyrene, polyacetal, polyamide, polypropylene, polystyrene, polyphenylene sulfide, polyetherimide, and polyetheretherketone can be used. Further, as the first additive, a fibrous or powdery additive made of any one of carbon, ferrite, aluminum oxide, aluminum nitride, silicon magnesium nitride, magnesium oxide, and silicon carbide can be used. . As the second additive, a fibrous or powdery additive made of any one of carbon, ferrite, aramid resin, and glass can be used.

  In this case, by appropriately combining the metal material, the resin material, and the first and second additives, the metal molded part can be a heat radiating part having a thermal conductivity of 5 to 160 W / m · k, The resin molded part can be a heat insulating part having a thermal conductivity of 0.5 W / m · k or less. By providing the metal forming part with a heat radiating surface exposed on the outer peripheral surface of the composite molded body, an integrally molded product having excellent heat dissipation can be obtained.

  Moreover, each of the heat-radiating part and the heat-insulating part can be formed in a necessary part of the integrally molded product by separating the resin-molded part that is the heat-insulating part by a part of the metal-forming part that is the heat-dissipating part.

It is a schematic sectional drawing which shows embodiment of the integrally molded product of the metal and resin provided with the electromagnetic wave shielding property to which this invention is applied. It is a schematic sectional drawing which shows another example of an integrally molded product. It is a schematic sectional drawing which shows embodiment of the integrally molded product of the metal and resin provided with the heat dissipation to which this invention is applied.

  Hereinafter, an embodiment of an integrally molded product of metal and resin to which the present invention is applied (hereinafter sometimes simply referred to as “integrated molded product”) will be described with reference to the drawings.

[Embodiment 1: Integrated molded product having electromagnetic shielding properties]
FIG. 1 is a schematic cross-sectional view showing an integrally molded product having electromagnetic wave shielding properties. An integrally molded product 1A according to the present embodiment includes a composite molded body 2 molded by a two-color injection molding method. The composite molded body 2 has a configuration in which the metal molded portion 3 and the resin molded portion 4 are integrated by heat fusion. A predetermined amount of the first additive 5 is mixed and dispersed in the metal forming portion 3. A predetermined amount of the second additive 6 made of a material different from that of the first additive 5 is mixed and dispersed in the resin molded portion 4.

  The composite molded body 2 is, for example, a plate material having a constant thickness, and includes a rectangular main body plate portion 2a and an outer peripheral plate portion 2b that is bent at right angles from the four peripheral edges of the main body plate portion 2a to the back surface side. The front side portion of the composite molded body 2 is formed by the metal molding portion 3, and the rear side portion is formed by the resin molding portion 4. Thereby, the metal forming part 3 is exposed on the surface 2c of the main body plate portion 2a of the composite molded body 2 and the outer surface 2d of the outer peripheral plate portion 2b. Further, the resin molded portion 4 is exposed on the back surface 2e of the main body plate portion 2a and the inner side surface 2f of the outer peripheral plate portion 2b. A rectangular frame-shaped end face 2g facing the back side of the composite molded body 2 has the metal molding portion 3 exposed at the outer half thereof and the resin molding portion 4 exposed at the inner half thereof. A predetermined finishing process is applied to the front surface, the back surface, and the like of the composite molded body 2 to form an integrally molded product 1A.

  Here, the metal forming part 3 is formed of a so-called low melting point metal material. Generally, a metal or alloy having a melting point of 250 ° C. or lower is used. Moreover, it is desirable to use any one of polycarbonate, ABS, polystyrene, polyacetal, polyamide, polypropylene, polystyrene, polyphenylene sulfide, polyetherimide, and polyetheretherketone as the resin material of the resin molded portion 4. It is also possible to use other thermoplastic resins.

  On the other hand, as each of the first additive 5 and the second additive 6, a fibrous or powdery additive made of one of glass, carbon, ceramics, and polymer can be used. Specifically, as the first additive 5, a fibrous (filler) or powdery additive made of carbon, ferrite, aluminum oxide, aluminum nitride, silicon magnesium nitride, magnesium oxide, or silicon carbide is used. it can. As the second additive 6, carbon, ferrite, aramid resin, or a fiber (filler) or powder additive made of glass can be used.

  For example, carbon fiber (filler) or carbon powder as a first additive 5 is blended in the metal forming part 3 as a first additive 5 in a low melting point metal at a predetermined ratio. In the resin molding portion 4, ferrite fiber (filler) or ferrite powder is added to the thermoplastic resin as a second additive 6 at a predetermined ratio.

  According to this configuration, since the first and second additives 5 and 6 do not interfere with the respective electromagnetic wave shielding characteristics, the integrally molded product 1A having good electromagnetic wave shielding characteristics from the low band to the high band is obtained. can get. In the case of this example, carbon is excellent in electromagnetic shielding properties in the 0.1 to 1000 MHz band, and ferrite is excellent in electromagnetic shielding properties in the 30 MHz to 40 GHz band. The electromagnetic wave shielding property in the band between these is obtained by the metal material of the metal forming part 3. Therefore, as indicated by solid and broken arrows in FIG. 1, electromagnetic waves in different bands are reliably reflected by the metal molding part 3 and the resin molding part 4, respectively. Therefore, the integrally molded product 1 </ b> A exhibits good electromagnetic wave shielding properties over a wide frequency band of 0.1 MHz to 40 GHz.

  In this example, the metal molding part 3 is laminated on the front surface side of the integrally molded product 1A, and the resin molding part 4 is laminated on the back surface side. On the contrary, it is also possible to adopt a configuration in which the resin molded portion 4 is laminated on the front surface side of the integrally molded product 1A and the metal molded portion 3 is laminated on the back surface side.

(Modification of Embodiment 1)
Next, FIG. 2 is an explanatory view showing a modification of the integrally molded product 1A for electromagnetic wave shielding in FIG. Since the basic configuration of the integrally molded product 1B shown in FIG. 2 is the same as that of the integrally molded product 1A of FIG. 1, the corresponding parts are denoted by the same reference numerals, and description thereof is omitted.

  On the metal molding portion 3A of the integrally molded product 1B, a partition portion 3a having a constant thickness extending from the front surface 2c side in the thickness direction and reaching the back surface 2e is formed. The front end surface 3b on the back surface side of the partition portion 3a is exposed on the back surface 2e. The resin molded portion 4A includes portions 4a and 4b separated on the left and right by the partition portion 3a. These portions 4a and 4b are exposed on the back surface 2e, and are located on the same plane as the front end surface 3b of the partition portion 3a.

  In the integrally molded product 1B having this configuration, as indicated by an arrow in FIG. 2, electromagnetic waves in a frequency band that cannot be shielded by the metal forming portion 3A pass through the partition portion 3a from the front side to the back side or from the back side to the front side. Is possible. Accordingly, it is possible to realize a shield plate having selective electromagnetic wave shielding characteristics that can transmit electromagnetic waves in a necessary band and shield unnecessary electromagnetic waves.

[Embodiment 2: Integrated molded product with heat dissipation]
FIG. 3 is a schematic cross-sectional view showing an integrally molded product having heat dissipation to which the present invention is applied. The cross-sectional configuration of the integrally molded product 10 is the same as that of the integrally molded product 1B shown in FIG.

  That is, the integrally molded product 10 includes a composite molded body 12 molded by a two-color injection molding method. The composite molded body 12 has a configuration in which a metal molded portion 13A and a resin molded portion 14A are integrated by heat fusion. A predetermined amount of the first additive 15 is mixed and dispersed in the metal forming portion 13A. A predetermined amount of the second additive 16 made of a material different from the first additive 15 is mixed and dispersed in the resin molded portion 14A.

  The metal molding part 13A of the composite molded body 12 is, for example, a plate material having a constant thickness, a rectangular main body plate portion 12a, and an outer peripheral plate portion 12b that is bent at right angles from the four peripheral edges of the main body plate portion 12a to the back surface side. Is forming. Thereby, the metal forming portion 13A is exposed on the surface 12c of the main body plate portion 12a of the composite molded body 12 and the outer surface 12d of the outer peripheral plate portion 12b. The back surface side of the metal forming portion 13A is filled with the resin forming portion 14A, and a flat back surface 12e is formed.

  In the metal forming portion 13A, a partition portion 13a having a constant thickness extending from the front surface 12c side in the thickness direction to the back surface 12e is formed. The front end surface 13b on the back surface side of the partition portion 13a is exposed on the back surface 12e. The resin molding portion 14A includes portions 14a and 14b separated on the left and right by the partition portion 13a. These portions 14a and 14b are exposed on the back surface 12e, and are located on the same plane as the front end surface 13b of the partition portion 13a.

  The metal forming portion 13A is formed of a so-called low melting point metal material. Generally, a metal or alloy having a melting point of 250 ° C. or lower is used. Moreover, it is desirable to use any one of polycarbonate, ABS, polystyrene, polyacetal, polyamide, polypropylene, polystyrene, polyphenylene sulfide, polyetherimide, and polyetheretherketone as the resin material of the resin molded portion 14A. It is also possible to use other thermoplastic resins.

  On the other hand, the 1st additive 15 mix | blended with 13 A of metal forming parts is an additive provided with the heat dissipation used in order to improve the heat dissipation of the said metal forming part 13A. For example, carbon, ferrite, aluminum oxide, aluminum nitride, silicon magnesium nitride, or a fibrous (filler) or powder additive made of magnesium oxide can be used.

  On the other hand, the 2nd additive 16 mix | blended with the resin molding part 14A is an additive provided with the predetermined heat insulation used in order to improve the heat insulation of the said resin molding part 14A. For example, a fibrous (filler) or powder additive made of carbon, ferrite, aramid resin or glass can be used.

  By combining the low melting point metal material and the first additive 15 used for the metal forming part 13A with appropriate materials, the heat conductivity of the metal forming part 13A is made a heat radiating part of 5 to 160 W / m · k. be able to. Moreover, as a thermoplastic resin used for the resin molded portion 14A and the second additive 16, a heat insulating portion having a thermal conductivity of 0.5 W / m · k or less and a thermal conductivity of the resin molded portion 14 can be obtained by combining those of appropriate materials. can do.

  In the integrally molded product 10 configured as described above, the metal molded portion 13A that is a heat radiating portion is exposed on the surface 12c and the outer surface 12d, and these surfaces function as a heat radiating surface. Further, the end surface on the back surface side of the outer peripheral plate portion 12b and the front end surface 13b on the back surface side of the partition portion 13a are exposed on the back surface side. Therefore, the heat generated on the back surface side from these exposed surfaces is transmitted to the metal forming portion 13A and released to the front surface side through the metal forming portion 13A. Therefore, the heat generated on the back surface side of the integrally molded product 10 can be efficiently released to the front surface side.

  Further, the resin molded portion 14A, which is a heat insulating portion, is divided into left and right portions by a partition portion 13a that is a part of the metal molded portion 13A, thereby forming portions 14a, 14b that are isolated from each other. On the back surface side of the integrally molded product 10, heat is not transmitted to the portions facing the heat insulating portions 14a and 14b, and the heat insulation state is maintained. Therefore, the heat from the heat-generating component arranged on the back surface side of the integrally molded product 10 can be efficiently released to the outside through the metal molding portion 13A, and the component to be kept in the heat-blocking state is surely secured by the resin molding portion 14A. It can be maintained in a heat shut-off state.

  Furthermore, as described in the first embodiment, a predetermined electromagnetic wave shielding characteristic can be imparted to the metal molded part 13A, and a predetermined electromagnetic wave shielding characteristic can also be imparted to the resin molded part 14A by the added second additive 16. In addition, electromagnetic waves in a predetermined band can be transmitted through the partition portion 13a. Therefore, it is possible to obtain an integrally molded product having excellent heat dissipation / interrupting properties and excellent electromagnetic wave shielding / transmitting properties.

  In addition, as shown in FIG. 1, it is also possible to manufacture the integrally molded product in a state in which the metal molding part 13A and the resin molding part 14A are laminated.

[Other embodiments]
In the first and second embodiments, in order to reliably integrate the metal molded part and the resin molded part by two-color injection molding, there is little difference in shrinkage between the metal molded part and the resin molded part. desirable. For example, it is desirable that the difference in shrinkage rate is 0.1% or less.

In addition, it is desirable that the difference in the coefficient of thermal expansion between the metal molded part and the resin molded part is also small. For example, it is desirable that the difference in coefficient of thermal expansion is 1 × 10 ⁻⁵ or less.

  In this case, as the first additive compounded in the metal forming part, carbon, ferrite, aluminum oxide, aluminum nitride, silicon magnesium magnesium, or a fibrous (filler) or powdered additive made of magnesium oxide is used. It is desirable to use it.

  Further, as the second additive to be blended in the resin molded part, it is desirable to use a fibrous (filler) or powdery additive made of carbon, ferrite, aramid resin or glass.

1A, 1B, 10 Integrated molded product 2, 12 Composite molded body 2a, 12a Main body plate portion 2b, 12b Outer plate portion 2c, 12c Front surface 2d, 12d Outer side surface 2e, 12e Back surface 2f, 12f Inner side surface 2g, 12g End surface,
3, 3A, 13A Metal forming portions 3a, 13a Partition portions 3b, 13b Tip surfaces 4, 4A, 14A Resin forming portions 5, 15 First additive 6, 16 Second additive

Claims (9)

A composite molded body in which the metal molded part and the resin molded part are heat-sealed and integrated by two-color injection molding,
The metal forming part is formed of a metal material in which the first additive is mixed and dispersed,
The resin molded part is formed from a thermoplastic resin material in which a second additive made of a material different from the first additive is mixed and dispersed,
The metal material has a first electromagnetic shielding characteristic;
The first additive has a second electromagnetic shielding characteristic,
The second additive has a third electromagnetic wave shielding property, and is an integrally molded product of metal and resin. The metal material is a metal or alloy having a melting point of 250 ° C. or less,
The resin material is any one of polycarbonate, ABS, polystyrene, polyacetal, polyamide, polypropylene, polystyrene, polyphenylene sulfide, polyetherimide, polyetheretherketone,
2. The metal and resin integral according to claim 1, wherein each of the first additive and the second additive is a fibrous or powdery additive made of one of glass, carbon, ceramics, and polymer. Molding. The first additive is a fibrous or powdery additive made of any one of carbon, ferrite, aluminum oxide, aluminum nitride, silicon magnesium nitride, magnesium oxide, silicon carbide,
3. The metal-resin integral molded product according to claim 2, wherein the second additive is a fibrous or powdery additive made of any one of carbon, ferrite, aramid resin, and glass. One of the first additive and the second additive is a fibrous or powdery additive made of carbon,
4. The metal-resin integral molded product according to claim 3, wherein the other of the first additive and the second additive is a fibrous or powdery additive made of ferrite. 5. The metal forming part is a heat radiating part having a thermal conductivity of 5 to 160 W / m · k,
The resin molded part is a heat insulating part having a thermal conductivity of 0.5 W / m · k or less,
5. The metal-resin integrated molded product according to claim 3, wherein the metal molded part includes a heat radiating surface exposed on an outer peripheral surface of the composite molded body. The difference in shrinkage between the metal molded part and the resin molded part is 0.1% or less,
6. The metal-resin integral according to claim 3, wherein a difference in coefficient of thermal expansion between the metal molded part and the resin molded part is 1 × 10 ⁻⁵ or less. Molding. The composite molded body is plate-shaped,
The metal molded part and the resin molded part are laminated in the thickness direction of the composite molded body,
On the surface of the composite molded body, one of the metal molded part and the resin molded part is exposed,
The metal-resin integral molded product according to any one of claims 1 to 6, wherein the other of the metal molded part and the resin molded part is exposed on the back surface of the composite molded body. The metal molded part is exposed on the surface and outer peripheral surface of the composite molded body,
The metal-resin integral molded product according to claim 7, wherein the resin-molded portion is exposed on the back surface of the composite molded plate. The metal forming part includes at least one partition part extending from the front surface to the back surface along the thickness direction,
The metal-resin integral molded product according to claim 7 or 8, wherein the resin-molded portion is divided by the partition portion.

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