JP2000198163A - Composite molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a composite molding adapted to an application such as a gasket with a cover or the like having excellent vibration damping properties without necessity of complicated steps by integrating a metal plate obtained by laminating a high hardness thermoplastic material having a specific JIS-A hardness with a thermoplastic material by heat fusion bonding. SOLUTION: After a high hardness thermoplastic material having a JIS-A hardness of 45 deg. or above is laminated on a metal plate 5, a thermoplastic material is heat fusion bonded by an injection mold or the like. Here, as the high hardness thermoplastic material, a polypropylene or the like is used, and as the plate 5, an aluminum or the like is used. Further, as the thermoplastic material, a styrene thermoplastic elastomer or the like of a low hardness thermoplastic material is used. A molding made of a polypropylene layer 4, the plate 5 and a thermoplastic elastomer layer is formed. Thus, a composite molding having good vibration damping properties and adapted to an application such as a gasket with a cover or the like can be manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite molded article in which a metal plate and a thermoplastic material are integrated. More specifically, the present invention relates to a method in which a metal plate and a thermoplastic material are formed without subjecting the metal plate to a base treatment. Also, the present invention relates to a composite molded body that is integrated without using an adhesive and is suitable for use as a gasket with a lid used for housing electronic devices and the like.

[0002]

2. Description of the Related Art In recent years, the development of electronic devices has been remarkable. These electronic devices use integrated circuits using semiconductors and are printed and wired on a substrate.
The weight has been reduced. These electronic devices dislike moisture, dust, and the like, and the sealing property of a case that stores the electronic devices is an important factor for the performance and durability of the electronic devices.

[0003] A case for accommodating electronic equipment and the like is composed of a box and a lid, and the box and the lid are integrated with a mating surface of them by sandwiching a gasket made of a thermoplastic material. Normally, the gasket takes the form of a gasket with a lid fixed to the lid, this is fixed by a method of fixing the gasket to the lid with double-sided tape, making holes in the lid, and opening the holes from both sides of the lid. It is performed by a method of fixing the gasket material by sandwiching it. The method of fixing the gasket to the lid with a double-sided tape is usually a method of punching a sheet-like gasket material to which the double-sided tape is stuck into a gasket shape, and fixing the gasket to the lid. In this method, most of the sheet-like gasket material after the punching is discarded as waste material, and since the gasket material is punched into a gasket shape and then fixed to the lid, the process becomes complicated, so the cost is increased. There is a problem that it becomes a factor. Further, in a gasket with a lid manufactured by a method of sandwiching a perforated lid with a gasket material, the gasket material is exposed at an upper portion of the lid, and the adhesion between the gasket material and the lid is insufficient. Therefore, when inserting the lid into the space of the electronic device body which has been narrowed due to recent miniaturization of electronic device parts, the gasket material exposed at the top of the lid may be rolled up. There is a problem that the winding causes poor sealing performance. Furthermore, when a gasket with a lid manufactured by such a method is used in a hard disk drive, there is a problem that vibration due to rotation of the hard disk cannot be suppressed.

[0004] On the other hand, the bonding between a thermoplastic material and a metal plate is usually performed by applying a base treatment to the surface of the metal plate, applying an adhesive to the surface, and bonding the thermoplastic material. In addition, in order to improve the adhesiveness, an adhesive (tacky) material is blended with a thermoplastic material. However, when a thermoplastic material is bonded to a metal plate using an adhesive, a process such as a base treatment of the metal plate or an application of an adhesive is required, so that the process is complicated, which causes a problem of an increase in cost. There is. In addition, when a molded body obtained by bonding a thermoplastic material and a metal plate is in the form of a gasket with a lid, and is used in precision electronic equipment, etc., the precision electronic equipment is used for gas generated due to a base treatment or an adhesive. There is a problem that it becomes difficult to use such as.
In addition, when an adhesive (tacky) material is blended with a thermoplastic material, there is a problem that handling is extremely difficult due to tacking (self-adhesion) of the blend, and the like. There is a problem that physical properties such as compression set of the thermoplastic material are deteriorated by blending the materials, and the thermoplastic material does not function as a gasket material.

[0005]

An object of the present invention is to provide a composite molded body which can be manufactured without requiring complicated steps, has excellent vibration damping properties, and is suitable for uses such as a gasket with a lid. It is intended for.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, laminated a metal plate with a high-hardness thermoplastic material, and laminated the laminated metal plate with another thermoplastic resin. It has been found that a composite molded body in which the material is integrated can achieve the object. The present invention has been completed based on such findings. That is, the present invention
An object of the present invention is to provide a composite molded body in which a thermoplastic material is integrated with a metal plate on which a high-hardness thermoplastic material having a JIS-A hardness of 45 ° or more is laminated by heat fusion.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The composite molded article of the present invention is
It can be manufactured by heat-sealing a metal plate laminated with a high-hardness thermoplastic material having an A hardness of 45 ° or more and a thermoplastic material by a method such as injection molding. JIS
Examples of the high hardness thermoplastic material having an A hardness of 45 ° or more include polyolefins such as polypropylene and polyethylene, polystyrene, and vinyl chloride. Examples of the metal plate include, but are not limited to, those made of aluminum, iron, or stainless steel. Various materials can be used as the thermoplastic material to be heat-fused to the metal plate. When the composite molded body is used as a gasket with a lid, the JIS-A hardness is 60 °.
Low hardness thermoplastic materials of less than are preferred. Examples of the low-hardness thermoplastic material include a styrene-based thermoplastic elastomer, an olefin-based thermoplastic elastomer, and a urethane-based thermoplastic elastomer. In particular, in a case for housing electronic devices, it is preferable to use a material that reliably shuts off moisture and air and that does not generate a halogen-based gas or an acid gas. From the viewpoint, those having a JIS-A hardness of less than 60 ° are preferred. Particularly, those having a angle of 15 ° to 45 ° are preferable.
Specifically, styrene-ethylene / butylene-styrene /
An elastomer made of a block copolymer (hereinafter, referred to as “styrene-based thermoplastic elastomer”) may be used. Examples of the styrene-based thermoplastic elastomer include Lavalon manufactured by Mitsubishi Chemical Corporation and Elastomer AR manufactured by Aron Kasei Co., Ltd. An example of the former is, for example, Lavalon MJ4300B
(Trade name, JIS-A hardness 45 °), Lavalon T320
C (trade name, JIS-A hardness 15 °). Styrenic thermoplastic elastomers do not require vulcanization for molding, unlike EPDM rubber and butyl rubber, and are recyclable, so that they greatly contribute to cost reduction.

[0008] By adopting such a structure, the metal plate is not subjected to a base treatment, an adhesive is not used, or an adhesive (adhesive) material is not blended with a thermoplastic material. And the thermoplastic material can be integrated, so that the metal plate and the thermoplastic material can be easily integrated without deteriorating the physical properties of the thermoplastic material. In addition, the composite molded body has good vibration damping properties because the metal plate is laminated with a high-hardness thermoplastic material, and is suitable for use as a gasket with a lid (see FIG. 1 described later) used in electronic devices and the like. is there. Particularly, in the case of a composite molded body (see FIGS. 2 and 3 described later) in which a low-hardness thermoplastic material layer is formed on both sides of a laminated metal plate by making holes in the laminated metal plate, the metal surface is used as a sealing surface side. Since the low-hardness thermoplastic material layer and the high-hardness thermoplastic material are fused together, the low-hardness thermoplastic material layer exposed at the top of the lid is less likely to be turned up, and static electricity and gas are generated. It is less likely to be used and is suitably used as a gasket with a lid. Further, by mixing a conductive material into a high-hardness thermoplastic material or a thermoplastic material, it is possible to prevent adhesion of dirt such as dust and leakage of electromagnetic waves. Further, by mixing a material having good heat dissipation into the high hardness thermoplastic material, heat generated inside can be radiated to the outside, so that heat storage in the hard disk can be prevented.

[0009]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Example 1 FIG. 1 is a perspective view showing a gasket with a lid for a case for accommodating a hard disk drive device, which is an embodiment of the composite molded article of the present invention. This is the view I saw.). The gasket 1 is in close contact with the surface of a metal lid 2, and the lid 2 serves as a lid of a hard disk drive device storage case. In the center gap portion of the gasket with the lid, devices such as a magnetic disk, a magnetic head, and an actuator are arranged on the box side of the hard disk drive device storage case,
These devices are closed by a metal box (not shown) and a gasket with a lid, and stored in a hard disk drive device storage case. The lid 2 is formed by laminating a polypropylene (Noblen AX568, manufactured by Sumitomo Chemical Co., Ltd., Rockwell R105 ° (JIS-A hardness 100 ° or more)) to a thickness of 120 μm on an iron plate having a thickness of 0.5 mm. Styrene-based thermoplastic elastomer (Lavalon MJ4300B, JIS-A hardness 45 °, manufactured by Mitsubishi Chemical Corporation)
Was subjected to insert molding using an injection molding machine to a thickness of 1 mm to obtain a gasket with a lid. The injection conditions were such that the nozzle and cylinder temperatures were 180 ° C., respectively, and the mold and insert iron plate temperatures were room temperature. When a peel test (based on JIS Z 0337) between the styrene-based thermoplastic elastomer and the metal plate was performed on the obtained gasket with the lid, the material of the styrene-based thermoplastic elastomer itself was broken or peeled at the interface between the iron plate and polypropylene. The force (adhesion) was 30 N / 25 mm or more. On the other hand, when the styrene-based thermoplastic elastomer was bonded to an iron plate without lamination using an adhesive, the peeling force was 20 N / 25 mm.

[0010] The gasket with a lid manufactured in this manner was used as a lid of a hard disk drive storage case, that is, the gasket was placed in the hard disk drive, and after 30 days of use, the gasket was visually observed. No fouling was observed, and the dustproof property during use was also good. In addition, when the vibration suppression performance of the gasket with the lid in the hard disk drive was observed, the resonance due to the hard disk was observed when the iron plate without the laminate was used, whereas the resonance due to the hard disk was recognized in the gasket with the lid. I couldn't.

Embodiment 2 The same laminated metal plate as that used in Embodiment 1 is provided with a large number of small holes a, and the lid 3 shown in FIGS. 2 and 3 is used. Then, a thermoplastic elastomer was injection-molded to obtain a gasket with a lid having a cross section shown in FIG. In FIG. 3, 4 is a polypropylene layer, 5 is a metal plate, and 6 is a thermoplastic elastomer layer. The thickness of the thermoplastic elastomer layer 6 on the polypropylene layer 4 side is 0.4.
mm, the thickness of the thermoplastic elastomer layer 6 on the metal plate 5 side,
That is, the thickness of the gasket was 1.0 mm. The gasket with the lid thus produced was used as a lid of a hard disk drive storage case, that is, the gasket was placed in the hard disk drive, and the gasket was visually observed after being used for 30 days.
No settling of the gasket was observed, and the dustproof property during use was good. In addition, no curling was generated in the outer thermoplastic elastomer layer, and no generation of static electricity or gas was observed. As is clear from the evaluation results in each of the above embodiments, the gasket with the lid according to the present invention can be easily manufactured, and the gasket and the lid have good adhesion. When used as a lid for a storage case, it had good dust-proofing properties and the gasket was made of a low-hardness material, so that it did not deform even after long-term use.

[0012]

According to the composite molded article of the present invention, a metal plate and a thermoplastic material are integrated without applying a base treatment to the metal plate and without using an adhesive, so that the metal plate can be housed in electronic equipment and the like. It is suitable for uses such as a gasket with a lid to be used.

[Brief description of the drawings]

FIG. 1 is a perspective view of a gasket with a lid according to the present invention.

FIG. 2 is a plan view of a lid according to the present invention.

FIG. 3 is an enlarged view of a cross section taken along line AA when a low-hardness thermoplastic material layer is formed on the lid shown in FIG.

[Explanation of symbols]

 1: Gasket 2: Lid 3: Lid 4: Polypropylene layer 5: Metal plate 6: Thermoplastic elastomer layer

Claims (5)

[Claims] 1. A composite molded article in which a thermoplastic material is integrated with a metal plate laminated with a high-hardness thermoplastic material having a JIS-A hardness of 45 ° or more by thermal fusion. 2. The thermoplastic material has a JIS-A hardness of 60 °.
The composite molded article according to claim 1, wherein the composite molded article is a low-hardness thermoplastic material having a hardness of less than. 3. A metal plate on which a high-hardness thermoplastic material is laminated, wherein a hole is provided in a peripheral portion, and a low-hardness thermoplastic material layer is formed on both surfaces of the laminated metal plate. 3. The composite molded article according to 1 or 2. 4. The composite molded article according to claim 1, wherein the composite molded article is a gasket with a lid. 5. The composite molded body according to claim 3, wherein the composite molded body is a gasket with a lid, and the metal surface side of the laminated metal plate is used as the sealing surface side.