JP2961068B2 - Gasket material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gasket material which is completely sealed between water and air, and which has no harmful gas and is mainly sandwiched between a box housing electronic equipment and a lid. .

[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,
Moreover, the printed wiring is formed on the substrate, and the size and weight are reduced. These electronic devices dislike moisture, dust, and the like, and their sealing properties are important factors for the performance and durability of the electrical devices.

For this reason, in general electronic equipment, a gasket material is sandwiched between mating surfaces of a box and a lid housing the electronic device with screws or the like. Urethane foam material of high density was used. However, this urethane foam material is foamed into a thin sheet, and is punched from this sheet according to the size used as a gasket material, and most of the sheet after punching is discarded as waste material. It had been. This urethane foam gasket has such wasteful surfaces and has relatively large compression set, so that moisture may enter the interior for long-term use, thereby reducing the durability of the electronic equipment itself. It was supposed to be lowered.

In recent years, a gasket material made of a vulcanized rubber material such as butyl rubber or EPDM rubber has been adopted, and the problem of permanent compression set has been improved. However, since the material constituting the gasket material is basically a vulcanized rubber, there is a major disadvantage in manufacturing that it takes time for molding. Further, it is not sufficient to change the hardness of the gasket material in a wide range, and there are many points where improvement is required.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and provides a gasket material having good sealing properties for moisture and air and excellent compression set characteristics. Further, the present invention provides a gasket material having excellent moldability and mountability to electronic devices.

[0006]

The present invention has the following configuration to achieve the above object. That is, the first aspect of the present invention is a gasket material that is interposed between a box housing electronic devices and a lid to block moisture and air, and does not generate a halogen-based gas and an acid gas. And hardness 1
It is characterized by comprising an elastomer made of styrene-ethylene / butylene-styrene / block copolymer having a degree of 5 to 60 degrees (JIS-A). In particular, it is known that a material having a hardness of about 35 to 50 degrees (JIS-A) has good workability.

A second aspect of the present invention is a gasket which is interposed between a box housing electronic devices and a lid to block moisture and air, and is divided into a box and a lid. And a hardness of 15 to 60 degrees (without generation of halogen-based gas and acid gas attached to the frame)
A) an elastomer made of styrene-ethylene-butylene-styrene block copolymer of A). Preferably, the elastomer is mounted on both sides of the frame by injection molding.

[0008]

The most significant feature of the gasket material of the present invention is that of a styrene-ethylene / butylene-styrene block copolymer, that is, a hydrogenated SBS block copolymer (SEBS).
Is adopted as the base material of the gasket material. First, since this SEBS is a thermoplastic elastomer, the gasket material can be easily obtained by the injection molding method. That is, a gasket material can be obtained simply by injecting an elastomer into a mold. The molding does not require a vulcanization time such as EPDM rubber or butyl rubber, and the material is recyclable, which significantly reduces cost. Will be contributed to.

The SEBS can be selected from a wide range of hardness, and has an excellent surface as a gasket material. Furthermore, it has excellent compression set characteristics, and has extremely low permeation of moisture and air, and is suitable as a gasket material. More specifically, SEBS, which is the base material of the gasket material, is a gasket material that does not generate halogen-based gas or various acidic gases, and has no adverse effect on materials constituting electronic devices and the like.

The hardness of the SEBS material is 15 to 60 degrees (JIS-A), preferably 30 to 50 degrees (JIS-A).
SA). That is, the lower the hardness, the better the adhesion / adhesiveness to the box or lid, but on the other hand, the handling is somewhat inconvenient, so the lower limit is 15 degrees, and the higher the hardness, the easier the handling Is disadvantageous in terms of adhesion, and the upper limit is determined by itself. Examples of the SEBS polymer include Lavalon manufactured by Mitsubishi Chemical and Elastomer AR manufactured by Aron Kasei.
J4300 (trade name).

Regarding the measurement of a halogen-based gas and an acid gas, the former is a GC-IR (JIR-35 manufactured by JEOL).
10) The latter used an ion chromatograph (IC-7000) manufactured by Yokogawa Analytical Systems.

In the case of using a frame sandwiched between a box housing electronic devices and a lid (second invention), rigidity can be imparted to the entire gasket material. For this reason, the gasket material using this frame can be mounted as it is on a robot in an automation line associated with the integration of the box and the lid. The frame is preferably made of stainless steel, and may be made of resin.

[0013]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples. FIG. 1 is a perspective view showing a second gasket material of the present invention, and FIG. 2 is a sectional view taken along line AA of FIG. In the figure, reference numeral 1 denotes a stainless steel frame, and reference numerals 2 and 3 denote SEBS materials mounted on both sides of the frame 1. The frame 1 has a screw hole 1 for integrating a box and a cover (not shown). Are formed. This gasket material was obtained by first setting the frame 1 in a mold and injection molding SEBS having a hardness of 45 degrees, which is a thermoplastic elastomer, in the mold.

The EPDM rubber material used for the conventional gasket needs to be vulcanized at the time of molding, but in this regard, the SEBS material of the present invention does not need to be vulcanized at all, and the molding of the gasket material is simplified. It will be. The SEBS polymer used here was Lavalon MJ430 manufactured by Mitsubishi Chemical Corporation.
0.

It was confirmed whether or not gas was generated from the SEBS material as the base material of the gasket material. That is, generation of a halogen-based gas and an acid gas was measured. The former measurement is GC
-IR (JIR-3510), and the latter measurement was performed by ion chromatography (IC-7000). In the former, 100 mg of the sample was heated to 100 ° C. and the generated gas was measured. In the latter, 1 g of the sample was cut into about 2 mm square, immersed in 19 cc of pure water, and subjected to ultrasonic extraction (30 minutes × 4).
The measured aqueous solution was measured up to 100 cc and measured. As a result, generation of any halogen-based gas or acidic gas was not recognized.

The evaluation of the metal test piece (copper piece) was also performed. 2.4 g of the sample was put into a beaker together with the metal test piece, and the test piece after heating at 100 ° C. for 270 hours was inspected for abnormalities.

Further, oil resistance, chemical resistance and compression set were compared with those of the conventional EPDM rubber. The test method is JIS
Performed according to -K6301. As a result of the test, oil resistance and chemical resistance were superior to EPDM rubber, and compression set was equivalent to that of EPDM rubber.

[0018]

According to the present invention, there is provided a gasket material as described above, which has good properties as well as its properties. In particular, in the case of using a frame, the gasket material can be automated in assembling electronic equipment. And it is industrially excellent.

[Brief description of the drawings]

FIG. 1 is a perspective view of a gasket material according to a second embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line AA of FIG.

[Explanation of symbols]

 1 ‥‥ frame, 2, 3 ‥‥ SEBS material.

Claims (4)

(57) [Claims] 1. A gasket material that is interposed between a box housing electronic devices and a lid to block moisture and air, and that does not generate a halogen-based gas and an acid gas, and
A gasket material comprising a styrene-ethylene-butylene-styrene-block copolymer elastomer having a hardness of 15 to 60 degrees (JIS-A). 2. The gasket material according to claim 1, wherein the hardness is 35 to 50 degrees (JJS-A). 3. A gasket which is interposed between a box housing electronic devices and a lid to block moisture and air,
A frame having a shape defined by a box and a lid; and a styrene-ethylene / ethylene / hardness-free 15 to 60 degree (JXS-A) -hardened halogen-based gas or acidic gas-equipped frame. A gasket material comprising: a butylene-styrene block copolymer elastomer. 4. The gasket material according to claim 3, wherein said elastomer is mounted on both sides of said frame by injection molding.