KR20140081674A - Method for manufacturing composite molded article and method of improving heat dissipation - Google Patents

Abstract

Provided is a technology to improve the heat dissipation property of composite molded articles. As a method of manufacturing composite molded articles which include a resin part made of a thermoplastic resin composition and a metal part joined to the resin part, the present invention includes: a rough surface formation process of forming a rough surface on the joint surface of the metal part on which the resin part is to be joined through wet etching; and an integration process of placing the metal part after the rough surface formation process inside a mold and molding the melted thermoplastic resin composition inside the mold for injection molding to form the resin part and integrate the resin part and the metal part at the same time. The ten point-average roughness (Rz) on the rough surface measured according to JIS B 0601 is equal to or greater than 10 μm, and the bond strength between the resin part and the metal part is equal to or greater than 10 MPa.

Description

METHOD FOR MANUFACTURING COMPOSITE MOLDED ARTICLE AND METHOD OF IMPROVING HEAT DISSIPATION BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

The present invention relates to a method of manufacturing a complex formed article and a method of improving heat radiation.

BACKGROUND ART [0002] Composite molded articles in which a metal part such as aluminum or an aluminum alloy and a resin part made of a thermoplastic resin composition are integrally formed are conventionally used for an interior part of an automobile such as a console box around an instrument panel, And is used for external members of electronic devices such as digital cameras and cellular phones.

Examples of the method of integrating the metal part and the resin part include a method of forming fine irregularities by processing the surface of the metal part, a method of bonding using an adhesive or double-sided tape, a method of bonding the metal part and / A method of bonding both using a fixing member such as a projection or the like, a method of bonding both using a fixing member, or a method using a screw or the like. Among these methods, a method of forming fine irregularities in the metal part and a method of using an adhesive tend to be frequently used because of the high degree of freedom in designing the complex molded body recently.

Here, it is known that an adhesive for integrating the metal part and the resin part is expensive. Further, in the production of the above-mentioned composite formed article, there is a problem that the productivity of the composite formed article is deteriorated because the resin part and the metal part are separately molded and then integrated.

In order to solve the above problems, there is provided a method of manufacturing a complex molded body, comprising the steps of disposing a metal part whose surface has been chemically etched in advance in a cavity of a mold for injection molding, injecting a thermoplastic resin composition in a molten state into a cavity, (For example, refer to 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 article can be reduced. Further, since the resin part and the metal part are integrated at the time of molding the resin part in the complex formed article, the number of required steps is smaller and the productivity is also superior to the method using the adhesive.

However, the composite formed body obtained by such a complex molding method also has a problem that adhesion between the resin portion and the metal portion is small.

1. Japanese Patent Application Laid-Open No. 2001-225352

As a result of the investigation by the inventor, it has been found that if the adhesion between the resin part and the metal part in the composite formed article is small, the airtightness of the composite formed article deteriorates, and heat transfer at the interface between the resin part and the metal part is insufficient, I found out the point.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a technique for improving the heat radiation property of the composite formed article.

DISCLOSURE OF THE INVENTION The present inventors have conducted intensive studies in order to solve the above problems. As a result, it has been found that the above problems can be solved by setting the bonding strength of the obtained composite molded product to a predetermined range by a manufacturing method having a specific process, and have accomplished the present invention. Specifically, the present invention provides the following.

(1) A method for producing a complex formed article 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 roughened surface by wet etching on a surface to be joined with the resin part in the metal part;

An integral step of disposing a metal part after the roughening step in a mold for injection molding and injecting the thermoplastic resin composition in a molten state into the mold for injection molding to form a resin part and integrally integrating the resin part and the metal part and,

The ten point average roughness (Rz) in the above roughened surface measured according to JIS B 0601 is 10 占 퐉 or more,

Wherein the bonding strength between the resin part and the metal part is 10 MPa or more.

(2) The method according to (1), wherein the wet etching is a chemical etching.

(3) The resin part is an insulating part, and the metal part is a conductive heat-

The composite formed body further includes a conductive heat generating portion connected to the conductive heat dissipating portion through the insulating portion,

(1) or (2), further comprising a connecting step of connecting the conductive heating 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 radiation part, Is 10 MPa or more, the heat radiation from the resin part to the metal part is improved.

According to the present invention, there is provided a technique for improving heat dissipation of a composite formed article.

1 is a perspective view schematically showing a heat radiation structure according to the present invention.
Fig. 2 is a diagram schematically showing the composite molded body used in Examples and Comparative Examples. Fig. (a) is an exploded perspective view, (b) is a perspective view, and (c) is a view showing only a metal part.
Fig. 3 is a diagram schematically showing a method of measuring the bonding strength between the resin part and the metal part in the embodiment. Fig.
Fig. 4 is a diagram schematically showing a method of evaluating the heat release performance in the embodiment. Fig.
5 is a diagram schematically showing a sample (A) for evaluation of the airtightness evaluation and an insert metal part (B) in the evaluation sample according to the embodiment.
6 is a diagram schematically showing a test apparatus for airtightness evaluation performed in the embodiment.

Hereinafter, an embodiment of the present invention will be described. However, the present invention is not limited to the following embodiments.

≪ Manufacturing method of composite formed article >

The method for producing a complex formed article of the present invention includes at least a roughening step and an integrating step. Hereinafter, the method for producing the composite formed article of the present invention will be described in detail.

In the production of the composite molded article, first, the metal and the thermoplastic resin composition which are the raw materials of the metal portion and the resin portion are prepared.

The kind of the metal constituting the metal part is not particularly limited, and a suitable kind of metal may be suitably used in accordance with the use and the like. For example, alloys such as steel, cast iron, stainless steel, aluminum, copper, gold, silver and brass, aluminum alloys, zinc alloys, magnesium alloys and tin alloys can be used.

The method of producing the metal part is not particularly limited, and conventionally known methods can be applied. Such a method includes, for example, a high-pressure casting method. The high-pressure casting method is a casting method in which molten metal is pressed into a mold to produce a casting with a high dimensional precision in a short time in a large amount. In addition, in order to mold the produced metal part into a desired shape, a cutting process using a machine tool or the like can be used.

The kind of the thermoplastic resin composition constituting the resin part is not particularly limited, and a thermoplastic resin composition suitably preferred in accordance with the use and the like can be used.

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 kind of the thermoplastic resin contained in the thermoplastic resin composition. Therefore, the effect of the present invention is exhibited regardless of the kind of the thermoplastic resin. For this reason, for example, the kind of the thermoplastic resin to be used can be determined as follows.

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

As thermoplastic resins having excellent heat resistance and high thermal conductivity, polyarylene sulfide based resins can be mentioned.

As described above, according to the manufacturing method of the present invention, since the adhesion between the metal part and the resin part can be improved regardless of the kind of the thermoplastic resin, the optimum thermoplastic resin can be selected according to the application.

 [Roughening process]

 The roughening step is a step of forming a roughened surface by wet etching on the surface to be joined of the metal part and the resin part in the metal part. The intended bonding surface refers to a part or all of the surface of the metal part, and includes all or at least a part where the metal part and the resin part are actually bonded in a later-described integration step.

By forming the roughened surface on the surface to be joined, not only the adhesion between the resin part and the metal part of the composite formed article to be produced can be improved, but also the heat conduction at the interface between the resin part and the metal part is smooth.

In the roughening step of the present invention, the roughened surface is formed by wet etching on the surface to be joined. The roughened surface formed in the roughening process is fine irregularities on the surface. The roughness of the unevenness is such that the surface roughness (ten point average roughness Rz) of the metal surface on the rough surface measured according to JIS B 0601 is 10 탆 or more (preferably 10 to 100 탆). By setting the surface roughness of the metal surface to be within this range, it is possible to impart sufficient concavity and convexity to the surface to be joined in the metal part, and to melt the thermoplastic resin composition in a molten state injected in a later- The bonding strength of the metal part is increased. The roughness of the metal surface on the roughened surface can be easily adjusted to a desired range by adjusting the conditions of the wet etching (the treatment time and the kind of the treatment liquid). Particularly, depending on the kind of the treatment liquid, the amount of hydroxyl groups on the surface of the roughened surface can be increased, so that improvement by chemical bonding of the bonding strength between the resin part and the metal part can be expected.

The wet etching is not particularly limited as long as it is a technique capable of forming a roughened surface on a surface to be bonded, and conventionally known methods 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 from the viewpoint that necessary treatments can be easily carried out and the obtained molded article is highly airtight. A suitable method of wet etching can be selected in accordance with the size and roughness of the unevenness of the rough surface to be obtained.

 [Integration Process]

The integration step refers to a step of disposing a metal part after the roughening step in a mold for injection molding and injecting a thermoplastic resin composition in a molten state into a mold for injection molding to integrate the resin part and the metal part.

The conditions for the injection molding are not particularly limited, and suitable conditions can be appropriately set according to the physical properties of the thermoplastic resin composition and the roughened 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 molding of the present invention. By taking out the composite molding from the mold, the composite molding of the present invention can be obtained.

[Bond strength between resin part and metal part]

The bonding strength between the resin portion and the metal portion of the composite formed article in the present invention is 10 MPa or more (preferably 10 to 50 MPa). The inventors of the present invention have found that when the bonding strength between the resin part and the metal part in the complex molded body is 10 MPa or more, the adhesion between the resin part and the metal part is high and the heat transfer at the interface between the resin part and the metal part is good. Therefore, the composite molded article of the present invention has high airtightness as well as high heat dissipation. Therefore, the composite formed article of the present invention can be preferably used for a molded article requiring high heat dissipation, such as automobile parts, electronic parts, and the like.

The bonding strength between the resin part and the metal part in the complex formed article is measured as follows. The middle part of the metal part of the composite formed article having the shape shown in Fig. 2 is cut to obtain two samples for evaluation. The obtained evaluation sample is placed on a jig as shown in Fig. 3, and the jig is moved so as to push the resin part from the metal part in the arrow direction at a speed of 1 mm / min. The strength at the time when the resin part is separated from the metal part is measured as the bonding strength.

<Heat Radiating Structure>

The manufacturing method of the present invention is preferable as a method for manufacturing the heat radiation structure. First, a heat dissipating structure will be described with reference to Fig. Fig. 1 shows an example of the heat dissipating structure 1. Fig. The heat dissipating structure 1 has an insulating portion 2, a conductive heat dissipating portion 3, and a conductive heat generating portion 4. As shown in Fig. 1, the conductive heat-dissipating portion 3 and the conductive heat-generating portion 4 are connected to each other through the insulating portion 2. [

The insulating portion 2 corresponds to the resin portion in the above-described complex formed body, and the conductive heat dissipating portion 3 corresponds to the metal portion in the aforementioned complex formed body.

The heat radiation structure manufactured by the method of the present invention is excellent in the adhesion between the insulating portion 2 and the conductive heat radiation portion 3 and the adhesion between the insulating portion 2 and the conductive heat generating portion 4, The heat is transmitted smoothly at the interface between the conductive heat-dissipating portion 3 and the insulating portion 2 and the conductive heat-generating portion 4. [ Therefore, the heat radiation structure 1 manufactured by the method of the present invention has high performance as a heat radiation structure.

In particular, when the heat-radiating portion and the heat-generating portion are electrically coupled together as in the present embodiment, it is necessary to electrically insulate the heat-radiating portion from the heat-generating portion. In the case of such a heat-radiating structure, there is a problem that heat transmission is largely hindered by disposing the insulating portion 2 between the conductive heat-radiating portion 3 and the conductive heat-generating portion 4. However, the heat- , The heat transfer between the insulating portion and the conductive heat dissipating portion is smooth, so that the above problem does not occur. As the conductive heat generating portion 4, for example, electronic parts and the like can be mentioned.

Example

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

&Lt; Manufacturing method of composite formed article >

A schematic view of the composite formed article used in Examples and Comparative Examples is shown in Fig. (a) is an exploded perspective view of the composite formed article, (b) is a perspective view of the composite formed article, and (c) is a view showing only a metal part. The composite molding thus obtained was produced by the following method. In Fig. 2, the unit of dimension is mm.

As the thermoplastic resin composition constituting the resin part, a polyphenylene sulfide type resin composition (a resin composition containing 35 mass% of glass fibers as a filling material and having a melt viscosity of 160 Pa · s (310 ° C., 1000 s ^-1 ) 1135 MF1 &quot; manufactured by Nissan Chemical Industries, Ltd.) was used. Here, the melt viscosity of the polyphenylene sulfide type resin composition was measured as follows.

(Measurement of Melt Viscosity of Polyphenylene Sulfide Resin Composition)

The melt viscosity at a barrel temperature of 310 DEG C and a shear rate of 1000 sec &lt; ^-1 &gt; was measured using a capillograph of TOYO SEIKI Co., Ltd., using a 1 mmΦ x 20 mm L / flat die as a capillary.

(Plate material) composed of aluminum (A5052, thickness: 2 mm) was used as a metal part. The metal portion has a surface to be joined at a portion indicated by oblique lines in Fig. 2 (a). One of the following etching 1 or 2 was performed on the surface to be joined of the metal part.

<Etching 1>

The surface of the metal part was etched by immersing it in the etching solution A (aqueous solution) having the following composition for 1 minute to remove the rust-inhibitive film on the surface to be bonded of the metal part, and then immersing in the etching solution B (aqueous solution) having the following composition for 5 minutes . According to such etching, the surface of the metal part is roughened.

[Etching solution A (temperature 20 DEG C)]

Hydrogen peroxide 26g / L

Sulfuric acid 90 g / L

[Etching solution B (temperature 25 DEG C)]

Hydrogen peroxide 80 g / L

Sulfuric acid 90 g / L

Benzotriazole 5 g / L

Sodium chloride 0.2 g / L

<Etching 2>

The rust prevention film was removed only by immersing in the etching solution A (aqueous solution) having the following composition for 1 minute on the surface to be bonded of the metal part. According to such an etching, the surface of the metal part is not roughened.

[Etching solution A (temperature 20 DEG C)]

Hydrogen peroxide 26g / L

Sulfuric acid 90 g / L

The metal parts subjected to the etching 1 (Example 1) or the etching 2 (Comparative Example 1) were arranged in the molds, respectively, and the integrated process was carried out. The molding conditions are as follows. The shape of the composite molding used is shown in Fig.

[Molding conditions]

Molding machine: Sodick TR-40 VR (Vertical Molding Machine)

Cylinder temperature: 310 占 폚 -320 占 폚 -310 占 폚 -290 占 폚

Mold temperature: 160 ℃

Injection speed: 100mm / s

Boom pressure: 98MPa × 5 seconds

<Evaluation>

The joint strength, heat radiation property, and airtightness of the joint portion were evaluated for the composite formed body produced by the above method. Further, a single-liquid epoxy resin adhesive (&quot; XNR 3503 &quot; Nagase Chemtech product (curing condition: 120 x 10 min)) was used for one of the bonding surfaces (bonding surface 1) ("TSE 322", Momentive product (curing condition: 150 × 60 min)) was attached to the other joint surface (joint surface 2) of the metal part (Corresponding to &quot; Comparative Example 2 &quot; in Table 1) in which the resin portion and the metal portion were bonded to each other was evaluated in the same manner. The specific evaluation method is as follows.

 [Bond strength]

The middle portion of the metal part of the composite formed article having the shape shown in Fig. 2 was cut into two pieces to obtain evaluation samples. The obtained evaluation sample was placed on a jig as shown in Fig. 3, and the jig was moved so as to push the resin part from the metal part in the arrow direction at a speed of 1 mm / min. The strength at the time when the resin part was separated from the metal part was measured as the bonding strength. Tensilon UTA-50 kN (manufactured by Orientech) was used as a measuring instrument. The measurement results are shown in Table 1 (the values are average values in three tests).

 [Heat dissipation evaluation]

As shown in Fig. 4, a composite formed article was placed on an aluminum pedestal (provided on a hot plate) with a surface temperature of 150 DEG C, and the surface of the resin portion (measurement surface) at a portion 3 mm away from the resin- The temperature was measured using a thermography device (ThermaCAM CPA-7800 from Chino). The higher the measured temperature, the higher the heat dissipation of the composite formed article. The results of the measurement for each composite molding are shown in Table 1.

 [Confidentiality Evaluation]

Using the sample for evaluation shown in Fig. 5, the airtightness was evaluated using the test apparatus shown in Fig. In this evaluation sample, the resin molded article corresponds to the resin portion and the insert metal component corresponds to the metal portion. First, a composite formed body was set in a metal container portion of a pressure-tight airtight vessel through a rubber O-ring, and then fixed as if the composite formed body was sandwiched between metal cover portions (the container portion and the upper cover portion were crossed with male and female threads And fixed by this). The pressure-resistant airtight container was put into a water tank, and the compressed air valve was gradually opened until the pressure reached a desired pressure to raise the pressure in the pressure tight airtight container, and the presence or absence of air leakage from the metal part was confirmed. It was judged that the airtightness under the above pressure was good (also referred to as &quot; OK &quot;) when there was no air leakage in the stop state for one minute by applying a predetermined pressure. The test was started at a pressure of 0.1 MPa, and when it was OK, the test was carried out up to 0.6 MPa, sequentially increasing by 0.1 MPa. Table 1 shows the pressures at which air leakage was confirmed for each composite molded article.

 [Metal surface roughness (ten point average roughness (Rz))]

The surface to be bonded of each of the metal portions subjected to any one of the etching 1 or 2 and the surface to be bonded of the unetched metal portion was polished with a laser microscope (VK-9510 manufactured by KEYENCE CORPORATION) , And the ten-point average roughness (Rz) was determined based on JIS B0601.

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

1 heat-dissipating structure
2 insulation part
3 conductive heat sink
4 conductive heating part

Claims (4)

A method for producing a composite formed article 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 roughened surface by wet etching on a surface to be joined with the resin part in the metal part;
An integral step of disposing the metal part after the roughening step in a mold for injection molding and injecting the thermoplastic resin composition in a molten state into the mold for injection molding to form a resin part and integrating the resin part and the metal part and,
The ten point average roughness (Rz) in the above roughened surface measured according to JIS B 0601 is 10 占 퐉 or more,
Wherein the bonding strength between the resin part and the metal part is 10 MPa or more. The method according to claim 1,
Wherein the wet etching is chemical etching. 3. The method according to claim 1 or 2,
Wherein the resin part is an insulating part, the metal part is a conductive heat-
The composite formed body further includes a conductive heat generating portion connected to the conductive heat dissipating portion through the insulating portion,
And a connecting step of connecting the conductive heating portion and the insulating portion. Wherein the resin part is an insulating part and the metal part is a conductive heat-radiating part, wherein the bonding strength between the resin part and the metal part is 10 MPa Or more, thereby improving the heat radiation from the resin part to the metal part.

Images