JP6226724B2 - Method for producing composite molded body and method for improving heat dissipation - Google Patents

Description

  The present invention relates to a method for producing a composite molded body and a method for improving heat dissipation.

  A composite molded body in which a metal part such as aluminum or an aluminum alloy and a resin part composed of a thermoplastic resin composition are integrated has been conventionally used in automobile interior parts such as a console box around an instrument panel and around an engine. It is used for parts, interior parts, exterior members of electronic devices such as digital cameras and mobile phones.

  As a method of integrating the metal part and the resin part, a method of processing the surface of the metal part to form minute irregularities, a method of bonding using an adhesive or a double-sided tape, a folding back to the metal part and / or the resin part There are a method of providing a fixing member such as a piece or a claw and fixing the both using the fixing member, a method of bonding using a screw or the like. Among these, the method of forming minute irregularities on the metal part and the method of using an adhesive tend to be frequently used since they have a high degree of freedom in designing a composite molded body recently.

  Here, it is known that the adhesive for integrating the metal part and the resin part is expensive. Further, in the production of the above composite molded body, the resin part and the metal part need to be separately molded and then integrated, and thus there is a problem that the productivity of the composite molded body is lowered.

  As a method for producing a composite molded body that solves the above-described problems, a metal part whose surface has been chemically etched is placed in a cavity of a mold for injection molding, and a thermoplastic resin composition in a molten state is placed in the cavity. There is known a composite molding method for producing a composite molded body in which a metal part and a resin part are integrated by injection (see, for example, Patent Document 1).

  According to the composite molding method, since it is not necessary to use an adhesive, the manufacturing cost of the composite molded body can be reduced. Further, since the resin part and the metal part are integrated during the molding process of the resin part in the composite molded body, fewer steps are required than in the method using an adhesive, and the productivity is excellent.

  However, even with this composite molding method, there is a problem that the adhesive force between the resin part and the metal part in the composite molded body obtained is small.

JP 2001-225352 A

  As a result of the study by the inventors, when the adhesion between the resin part and the metal part in the composite molded body is small, not only the airtightness of the composite molded body is inferior, but also the heat transfer at the interface between the resin part and the metal part. It was found that the heat dissipation of the composite molded body was inferior because it was not sufficient.

  This invention is made | formed in order to solve the above subject, The objective is to provide the technique which improves the heat dissipation of a composite molded object.

  The inventors of the present invention have made extensive studies to solve the above problems. As a result, it has been found that the above-mentioned problems can be solved by setting the bonding strength of the obtained composite molded body within a predetermined range by a manufacturing method including a specific process, and has completed the present invention. Specifically, the present invention provides the following.

(1) A method for producing a composite molded body comprising: a resin part composed of a thermoplastic resin composition; and a metal part joined to the resin part,
A roughening step of forming a rough surface by wet etching on a surface to be bonded to the resin portion in the metal portion;
The metal portion after the roughening step is placed in an injection mold, and the molten thermoplastic resin composition is injected into the injection mold to form a resin portion, and And an integration step of integrating the resin part and the metal part,
Ten-point average roughness Rz on the rough surface measured in accordance with JIS B 0601 is 10 μm or more,
The manufacturing method of the composite molded object whose joint strength of the said resin part and the said metal part is 10 Mpa or more.

  (2) The method for producing a composite molded body according to (1), wherein the wet etching is chemical etching.

(3) The resin part is an insulating part, the metal part is a conductive heat dissipation part,
The composite molded body further includes a conductive heat generating part connected to the conductive heat radiating part via the insulating part,
The manufacturing method of the composite molded body according to (1) or (2), further including a connecting step of connecting the conductive heat generating portion and the insulating portion.

  (4) A composite molding comprising a resin part composed of a thermoplastic resin composition and a metal part joined to the resin part, wherein the resin part is an insulating part and the metal part is a conductive heat dissipation part. A method for improving heat dissipation from the resin part to the metal part by setting the bonding strength between the resin part and the metal part to 10 MPa or more in the body.

  According to the present invention, a technique for improving the heat dissipation of a composite molded body is provided.

It is a perspective view which shows typically the heat dissipation structure in this invention. It is a figure which shows typically the composite molded object used by the Example and the comparative example. (A) is an exploded perspective view, (b) is a perspective view, (c) is a figure which shows only a metal part. It is a figure which shows typically the measuring method of the joint strength between the resin part and metal part which was performed in the Example. It is a figure which shows typically the evaluation method of heat dissipation evaluation performed in the Example. It is a figure which shows typically the sample for evaluation (A) of the airtightness evaluation performed in the Example, and the insert metal component (B) in the sample for evaluation. It is a figure which shows typically the test apparatus of the airtightness evaluation performed in the Example.

  Hereinafter, embodiments of the present invention will be described. In addition, this invention is not limited to the following embodiment.

<Method for producing composite molded body>
The method for producing a composite molded body of the present invention includes at least a roughening step and an integration step. Hereafter, the manufacturing method of the composite molded object of this invention is explained in full detail.

  In producing the composite molded body, first, a metal and a thermoplastic resin composition, which are raw materials for the metal part and the resin part, are prepared.

  The type of metal constituting the metal part is not particularly limited, and a preferable type of metal can be used as appropriate depending on the application. For example, metals such as steel, cast iron, stainless steel, aluminum, copper, gold, silver, and brass, and alloys such as aluminum alloy, zinc alloy, magnesium alloy, and tin alloy can be used.

  The manufacturing method of the said metal part is not specifically limited, A conventionally well-known method is employable. An example of such a method is a high-pressure casting method. The high pressure casting method is a casting method in which a molten metal is press-fitted into a mold to produce a large amount of high dimensional accuracy castings in a short time. Moreover, in order to shape | mold the manufactured metal part in a desired shape, you may use the cutting process by a machine tool, etc.

  The kind of thermoplastic resin composition which comprises a resin part is not specifically limited, According to a use etc., a preferable thermoplastic resin composition can be used suitably.

  One of the features of the present invention is that the adhesion between the resin part and the metal part can be enhanced regardless of the type of the thermoplastic resin contained in the thermoplastic resin composition. Therefore, the effects of the present invention are exhibited regardless of the type of thermoplastic resin. For this reason, the kind of thermoplastic resin to be used can be determined as follows, for example.

  As an example of the optimal use of the composite molded body produced by the production method of the present invention, a heat dissipation structure (details will be described later) can be mentioned. When the composite molded body is used as a heat dissipation structure, it is preferable that the thermoplastic resin composition includes a thermoplastic resin having high heat resistance and high thermal conductivity.

  Examples of the thermoplastic resin having excellent heat resistance and high thermal conductivity include polyarylene sulfide-based resins.

  As described above, according to the production method of the present invention, the adhesive force between the metal part and the resin part can be improved regardless of the type of the thermoplastic resin. You can choose.

[Roughening process]
The roughening step is a step of forming a rough surface by wet etching on the planned joining surface of the metal portion and the resin portion in the metal portion. The surface to be bonded refers to a part or all of the surface of the metal part, and includes all or at least a part of the surface where the metal part and the resin part are actually bonded in the integration step described later.

  By forming a rough surface on the planned joining surface, not only can the adhesion between the resin part and the metal part of the composite molded body to be manufactured be improved, but also heat conduction at the interface between the resin part and the metal part. Becomes smooth.

  In the roughening step in the present invention, a rough surface is formed on the planned joining surface by wet etching. The rough surface formed in the roughening step is fine irregularities on the surface. The roughness of the irregularities is such that the metal surface roughness (10-point average roughness Rz) on the rough surface measured according to JIS B 0601 is 10 μm or more (preferably 10 to 100 μm). By making the metal surface roughness of the rough surface in such a range, sufficient unevenness can be imparted to the bonding planned surface in the metal part, and the molten thermoplastic resin composition injected in the integration process described later is in the unevenness. The penetration strength of the resin part and the metal part increases. The metal surface roughness on the rough surface can be easily adjusted to a desired range by adjusting wet etching conditions (processing time, type of processing liquid). In particular, depending on the type of treatment liquid, the amount of hydroxyl groups on the surface of the rough surface can be increased, and therefore an improvement in the bonding strength between the resin portion and the metal portion by chemical bonding can be expected.

  The wet etching is not particularly limited as long as it is a technique capable of forming a rough surface on the planned joining surface, and a conventionally known method can be used. For example, chemical etching using a liquid agent (for example, an aqueous solution containing hydrogen peroxide, sulfuric acid, benzotriazole, sodium chloride, etc.) can be suitably used. Chemical etching is preferable in that the necessary treatment can be easily performed and the resulting molded article has high airtightness. A wet etching method can be appropriately selected depending on the size of the rough surface to be obtained, the roughness, and the like.

[Integration process]
In the integration step, the metal portion after the roughening step is placed in an injection mold, and a thermoplastic resin composition in a molten state is injected into the injection mold. It refers to the process of integrating the part.

  The conditions for injection molding are not particularly limited, and preferable conditions can be appropriately set according to the physical properties of the thermoplastic resin composition and the state of the rough surface formed on the metal part.

  The thermoplastic resin composition injected into the injection mold is solidified, and the metal part and the resin part are integrated to complete the composite molded body of the present invention. The composite molded body of the present invention can be obtained by removing the composite molded body from the mold.

[Joint strength between resin part and metal part]
The bonding strength between the resin part and the metal part of the composite molded body in the present invention is 10 MPa or more (preferably 10 to 50 MPa). As a result of investigations by the inventors, if the bonding strength between the resin part and the metal part in the composite molded body is 10 MPa or more, not only the adhesion between the resin part and the metal part is high, but also the resin part and the metal part. It was found that the heat transfer at the interface between them is good. Therefore, the composite molded body in the present invention has not only airtightness but also high heat dissipation. Therefore, the composite molded body in the present invention can be preferably used as a molded body that is required to have high heat dissipation properties, such as automobile parts and electronic parts.

  The bonding strength between the resin part and the metal part in the composite molded body is measured as follows. The middle part of the metal part of the composite molded body having the shape shown in FIG. 2 is cut into two parts to obtain a sample for evaluation. The obtained sample for evaluation is placed on a pedestal (jig) as shown in FIG. 3, and the jig is moved so as to push away the resin part from the metal part in the direction of the arrow at a speed of 1 mm / min. The strength at the time when the resin portion is peeled from the metal portion is measured as the bonding strength.

<Heat dissipation structure>
The production method of the present invention is preferable as a method for producing a heat dissipation structure. First, the heat dissipation structure will be described with reference to FIG. FIG. 1 shows an example of the heat dissipation structure 1. The heat dissipation structure 1 includes an insulating portion 2, a conductive heat dissipation portion 3, and a conductive heat generating portion 4. As shown in FIG. 1, the conductive heat radiating part 3 and the conductive heat generating part 4 are connected via the insulating part 2.

  The insulating part 2 corresponds to the resin part in the above-mentioned composite molded body, and the conductive heat radiation part 3 corresponds to the metal part in the above-mentioned composite molded body.

  Since the heat dissipation structure manufactured by the method of the present invention has strong adhesion between the insulating portion 2 and the conductive heat dissipation portion 3 and between the insulating portion 2 and the conductive heat generating portion 4, The heat transfer at the interface between the conductive heat radiating part 3 and the insulating part 2 and the conductive heat generating part 4 is smooth. For this reason, the heat dissipation structure 1 manufactured by the method of the present invention has high performance as a heat dissipation structure.

  In particular, when both the heat dissipating part and the heat generating part are conductive as in this embodiment, it is necessary to electrically insulate between the heat dissipating part and the heat generating part. In the case of such a heat dissipation structure, the problem is that the heat transfer is greatly hindered by disposing the insulating portion 2 between the conductive heat dissipation portion 3 and the conductive heat generation portion 4. In the heat dissipation structure manufactured in (1), since the heat transfer between the insulating portion and the conductive heat dissipation portion is smooth, the above problem does not occur. In addition, as the electroconductive heat generating part 4, an electronic component etc. are mentioned, for example.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not limited to these Examples.

<Method for producing composite molded body>
A schematic diagram of the composite molded body used in the examples and comparative examples is shown in FIG. (A) is a disassembled perspective view of a composite molded object, (b) is a perspective view of a composite molded object, (c) is a figure which shows only a metal part. This composite molded body was produced by the following method. In addition, the unit of the dimension in FIG. 2 is mm.

As a thermoplastic resin composition constituting the resin part, a polyphenylene sulfide-based resin composition (containing 35% by mass of glass fiber as a filling material and having a melt viscosity of 160 Pa · s (310 ° C., 1000 s ⁻¹ ), poly “1135MF1” manufactured by Plastics Co., Ltd.) was used. The melt viscosity of the polyphenylene sulfide resin composition was measured as follows.
(Measurement of melt viscosity of polyphenylene sulfide resin composition)
Using a Capillograph manufactured by Toyo Seiki Co., Ltd., a melt viscosity at a barrel temperature of 310 ° C. and a shear rate of 1000 sec ⁻¹ was measured using a 1 mmφ × 20 mmL / flat die as a capillary.

  As a metal part, the plate-shaped object comprised from aluminum (A5052, 2 mm in thickness) was used. The said metal part has a joining plan surface in the part shown with the oblique line of Fig.2 (a). One of the following etchings 1 and 2 was applied to the planned joining surface of the metal part.

<Etching 1>
The metal part surface is immersed in an etching solution A (aqueous solution) having the following composition for 1 minute to remove the rust-preventive film and then immersed in an etching solution B (aqueous solution) having the following composition for 5 minutes. Was etched. According to this etching, the metal part surface is roughened.
[Etching solution A (temperature 20 ° C.)]
Hydrogen peroxide 26g / L
Sulfuric acid 90g / L
[Etching solution B (temperature: 25 ° C.)]
Hydrogen peroxide 80g / L
Sulfuric acid 90g / L
Benzotriazole 5g / L
Sodium chloride 0.2g / L

<Etching 2>
Only the rust preventive film removal was performed by immersing in the etching planned surface of a metal part for 1 minute in the etching liquid A (aqueous solution) of the following composition. According to this etching, the surface of the metal part is not roughened.
[Etching solution A (temperature 20 ° C.)]
Hydrogen peroxide 26g / L
Sulfuric acid 90g / L

The metal parts subjected to etching 1 (Example 1) or etching 2 (Comparative Example 1) were respectively placed in a mold and an integration process was performed. The molding conditions are as follows. The shape of the composite molded body used is as shown in FIG.
[Molding condition]
Molding machine: Sodick TR-40VR (vertical molding machine)
Cylinder temperature: 310 ° C-320 ° C-310 ° C-290 ° C
Mold temperature: 160 ° C
Injection speed: 100mm / s
Holding pressure: 98 MPa × 5 seconds

<Evaluation>
About the composite molded object produced by said method, the joining strength of the joining part, heat dissipation, and airtightness were evaluated. In addition, the metal part is not etched, and a one-part epoxy resin adhesive (“XNR3503” manufactured by Nagase ChemteX (curing condition: 120 ° C. × 10 min)) is used on one joint surface (joint surface 1) in the metal part. Then, the resin part and the metal part are joined together, and the other joint surface (joint surface 2) in the metal part is a thermosetting silicone adhesive sealing material (“TSE322”, manufactured by Momentive (curing condition: 150 ° C. × 60 min)). The composite molded body (corresponding to “Comparative Example 2” in Table 1) in which the resin part and the metal part were joined using the same was evaluated in the same manner. The specific evaluation method is as follows.

[Joint strength]
The middle part of the metal part of the composite molded body having the shape shown in FIG. 2 was cut into two parts to obtain evaluation samples. The obtained sample for evaluation was placed on a pedestal (jig) as shown in FIG. 3, and the jig was moved so as to push away the resin part from the metal part in the direction of the arrow at a speed of 1 mm / min. The strength at the time when the resin portion was peeled from the metal portion was measured as the bonding strength. In addition, Tensilon UTA-50kN (made by Orientec Co., Ltd.) was used as a measuring instrument. The measurement results are shown in Table 1 (values are average values in three tests).

[Heat dissipation evaluation]
As shown in FIG. 4, the composite molded body is placed on an aluminum table (installed on a hot plate) having a surface temperature of 150 ° C., and the surface of the resin part (measurement surface) 3 mm away from the resin side end face of the metal part immediately after placement. ) Was measured using a thermographic apparatus (Thermo CAM CPA-7800 manufactured by Chino). It shows that the heat dissipation of a composite molded object is so high that the measured temperature is high. The measurement results for each composite molded body are shown in Table 1.

[Airtight evaluation]
The evaluation sample shown in FIG. 5 was used, and the airtightness was evaluated using the test apparatus shown in FIG. In this evaluation sample, the resin molded product corresponds to the resin portion, and the insert metal part corresponds to the metal portion. First, the composite molded body was set in a metal container portion of a pressure-tight airtight container via a rubber O-ring, and then fixed so that the composite molded body was sandwiched between metal upper lid portions (the container portion and the upper lid portion were respectively Male and female threads are cut and fixed by this). The pressure-tight airtight container was put into a water tank, and the compressed air valve was gradually opened until the desired pressure was reached, and the pressure in the pressure-tight airtight container was increased, and the presence or absence of air leakage from the metal part was confirmed. If there was no air leakage in a state of standing for 1 minute under a predetermined pressure, it was determined that the airtightness under the pressure was good (also referred to as “OK”). The test started from a pressure of 0.1 MPa. If it was OK, the test was sequentially increased by 0.1 MPa, and the test was performed up to a maximum of 0.6 MPa. The pressure at which air leakage was observed for each composite molded body is shown in Table 1.

[Metal surface roughness (ten-point average roughness Rz)]
With a laser microscope (VK-9510, Keyence Co., Ltd.), the planned joining surface of each metal part subjected to either etching 1 or 2 and the planned joining surface of a metal part not etched are used. The surface of the planned joining surface was observed, and the 10-point average roughness Rz was determined based on JIS B 0601.

  As shown in Table 1, when the metal part and the resin part are bonded to each other through a rough surface having a ten-point average roughness Rz of 10 μm or more formed on the metal part by wet etching, the resin part and the metal part It can be seen that the joint strength increases with the heat dissipation and the airtightness is remarkably increased.

DESCRIPTION OF SYMBOLS 1 Heat dissipation structure 2 Insulation part 3 Conductive heat dissipation part 4 Conductive heat generating part

Claims (4)

A method for producing a composite molded body comprising a resin part composed of a thermoplastic resin composition, and a metal part joined to the resin part,
A roughening step of forming a rough surface by wet etching on a surface to be bonded to the resin portion in the metal portion;
The metal part after the roughening step is placed in an injection mold, and the molten thermoplastic resin composition is injected into the injection mold to form a resin part, and And an integration step of integrating the resin part and the metal part,
The ten-point average roughness Rz on the rough surface measured according to JIS B 0601 is 10 μm or more,
The manufacturing method of the composite molded object whose joint strength of the said resin part and the said metal part is 10 Mpa or more.   The method for producing a composite molded body according to claim 1, wherein the wet etching is chemical etching. The resin part is an insulating part, the metal part is a conductive heat radiating part,
The composite molded body further includes a conductive heat generating part connected to the conductive heat radiating part through the insulating part,
The manufacturing method of the composite molded object of Claim 1 or 2 which further has the connection process which connects the said electroconductive heat generating part and the said insulating part. In a composite molded body comprising a resin part composed of a thermoplastic resin composition and a metal part joined to the resin part, the resin part is an insulating part, and the metal part is a conductive heat dissipation part,
A rough surface is formed by wet etching on the planned joining surface of the resin part and the metal part,
The ten-point average roughness Rz on the rough surface measured according to JIS B 0601 is 10 μm or more,
A method of improving heat dissipation from the resin part to the metal part by setting the bonding strength between the resin part and the metal part to 10 MPa or more.

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