JP2001108109A - Gasket with frame and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gasket with a frame allowing reduction of generation of gas polluting a magnetic disk or the like when using an electronic apparatus, without providing a mechanism for removing the gas in an electronic apparatus body. SOLUTION: In this gasket with a frame wherein a frame body and a gasket are integrated, the frame body is made of a propylene homopolymer and/or a propylene copolymer mainly containing propylene not containing a lubricant or made of a heated propylene homopolymer and/or a heated propylene copolymer mainly containing propylene, while the gasket is made of an elastic material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gasket with a frame and a method of manufacturing the same, and more particularly, to a gasket with a frame for sealing a joint surface between a cover body and a main body of a lightweight device, for example, a hard disk device of a computer, and the like. It relates to a manufacturing method. The gasket with a frame of the present invention is a gasket with reduced generation of gas when using electronic equipment, and is completely sealed from water or air such as a hard disk device of a computer installed in a robot in an automation line or the like. Applicable to technology.

[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 and dust. Therefore, the sealing performance of the gasket that seals the joint surface between the box-shaped main body containing these integrated circuits and the cover body depends on the performance and durability of the electronic devices. Is an important factor for

[0003] For this reason, usually, a gasket is sandwiched between joint surfaces of a box body and a lid body containing these integrated circuits and the like.
Sealing and integration are performed by fastening with mounting bolts or the like, and a high-density urethane foam material has been used as a gasket material. The urethane foam material is foamed into a thin sheet shape, and an adhesive tape is stuck to the sheet and punched into a desired shape in many cases. Further, a gasket in which an elastomer is fixed to both surfaces of a frame, which is manufactured by inserting a frame made of stainless steel or a synthetic resin into a mold and then injection-molding an elastomer, has been proposed (JP-A-8-28369).
No. 8). This gasket has a gasket having rigidity by employing a frame, and has improved mountability to equipment. Examples of the synthetic resin forming the frame include acrylonitrile styrene (AS) resin, acrylonitrile butadiene styrene (ABS) resin, styrene resins such as polystyrene and syndiotactic polystyrene, olefin resins such as polyethylene and polypropylene, and nylon. Thermoplastic resins such as polyamide resins, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, modified polyphenylene ethers, acrylic resins, polyacetals and polycarbonates.

A gasket with a frame whose frame is formed of a thermoplastic resin is lighter in weight than a gasket with a frame whose frame is formed of a metal such as stainless steel, and when a thermoplastic elastomer is used as a gasket material, It has the property that adhesion between the body and the gasket is easy. However, when the temperature inside the electronic device body rises to 40 to 50 ° C. during actual use of the gasket with the frame, many of them generate gas that contaminates the magnetic disk, and the generated gas is deposited on a disk such as a hard disk device. It may accumulate and cause unreadable in the hard disk drive. For example, usually, about 0.05 to 5% of various additives are added to polypropylene depending on various uses. Among them, the lubricant is easy to volatilize and easily generates gas. In order to solve such inconveniences, a mechanism for adsorbing the generated gas is provided (Japanese Patent Laid-Open No. 6-302178). This problem is dealt with by providing a gas adsorbent in the breathing hole (JP-A-6-36548). However, the generation of gas from the gasket is for a long time, and the inconvenience of always generating gas when using electronic equipment cannot be avoided.In addition, the above-mentioned gas adsorption mechanism must promptly remove the generated gas. However, there is a problem that the effect of removing the gas is reduced when used for a long time.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a frame with a frame for reducing the generation of gas contaminating a magnetic disk or the like when the electronic device is used, without providing a mechanism for removing gas in the electronic device body. It is intended to provide a gasket.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have found that the frame is made of a specific propylene homopolymer and / or a propylene copolymer mainly composed of propylene. It has been found that, by forming with, the gas is not generated from the framed gasket during use of the electronic device, and the object can be achieved. The present invention has been completed based on such findings. That is, the present invention provides a gasket with a frame in which the frame and the gasket are integrated, wherein the frame is a propylene homopolymer containing no lubricant and / or
Or a propylene copolymer mainly composed of propylene, the gasket is made of an elastic body, and the frame and the gasket are characterized in that the frame and the gasket are integrated, and the frame and the gasket are integrated. In the framed gasket, the frame is made of a heat-treated propylene homopolymer and / or a propylene copolymer mainly composed of propylene, the gasket is made of an elastic body, and the frame and the gasket are integrated. It is another object of the present invention to provide a method of manufacturing a gasket with a frame, characterized in that the gasket with a frame and the frame and the gasket are integrated by a two-color molding method or an insert molding method.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the framed gasket of the present invention, the frame is made of a propylene homopolymer and / or a propylene copolymer containing propylene as a main component, or a propylene homopolymer and / or propylene that has been heat-treated. And a propylene copolymer mainly composed of As the propylene copolymer mainly composed of propylene, a copolymer of propylene and a small amount of other α-olefin (for example, propylene-ethylene copolymer, propylene / 4-
Methyl-1-pentene copolymer). Here, the polypropylene according to the present invention refers not to a polypropylene polymerized using a metallocene catalyst, but to a general polypropylene, specifically, an isotactic polypropylene or an atactic polypropylene, for example, mainly a Ziegler catalyst (Ti-based catalyst). ) In the presence of propylene. Among copolymers, a random copolymer is obtained by coexisting a small amount of ethylene or another α-olefin during polymerization, and a block copolymer is obtained by polymerizing propylene homopolymer and then mainly polymerizing ethylene. When a frame is formed from a propylene homopolymer and / or a propylene-based propylene copolymer (hereinafter referred to as polypropylene, etc.) containing no lubricant as a gas generation source, gas is generated even in an environment of 40 to 50 ° C. do not do. Here, the lubricant refers to an additive such as polypropylene which imparts lubricity necessary for facilitating molding processing, and specifically, a hydrocarbon-based lubricant such as paraffin and wax, and a fatty acid-based lubricant such as stearic acid. And metal soap-based lubricants such as calcium stearate, and fatty acid derivative-based lubricants such as fatty acid amides. The frame made of polypropylene or the like not containing a lubricant is preferably made of polypropylene or the like not containing an additive that generates a gas at a temperature of 120 ° C. or lower. Examples of the gas-generating additives include various stabilizers such as phenol-substituted products, antioxidants such as aromatic amines, ultraviolet absorbers such as hindered amines and benzophenones, and DOP (dioctyl phthalate). Various additives such as a plasticizer such as a phthalic acid ester, a flame retardant using a halogen-based flame retardant, antimony oxide, and a phosphorus flame retardant alone or in combination thereof are exemplified. Further, even in the case of polypropylene or the like containing a lubricant or the like, the contained gas can be removed by heat treatment. Therefore, if the frame is formed of heat-treated polypropylene or the like, no gas is generated even in an environment of 40 to 50 ° C. The heat treatment can be performed at a temperature of 80 to 150 ° C. for 1 to 48 hours, for example, at a temperature of 80 to 150 ° C., particularly at 100 to 130 ° C. for 5 to 24 hours. preferable.

As the thermoplastic elastomer forming the gasket, for example, thermoplastic elastomers such as styrene-based, olefin-based, urethane-based and ester-based thermoplastic elastomers can be used. In particular, at least a polymer block mainly composed of a vinyl aromatic compound is used. One containing a copolymer thermoplastic elastomer composed of one and at least one of polymer blocks mainly composed of a conjugated diene compound is preferably used. More specifically, for example, a block copolymer of crystalline polyethylene and ethylene / butylene-styrene random copolymer obtained by hydrogenating a block copolymer of polybutadiene and butadiene-styrene random copolymer, A block copolymer of polybutadiene and polystyrene, and a block copolymer of polyisoprene and polystyrene, or obtained by hydrogenating a block copolymer of polybutadiene or an ethylene-butadiene random copolymer and polystyrene, for example, Diblock copolymer of crystalline polyethylene and polystyrene, styrene
Ethylene / butylene-styrene triblock copolymer (SEBS), styrene-ethylene / propylene-styrene triblock copolymer (SEPS), among others, styrene-ethylene / butylene-styrene block copolymer or styrene-ethylene / Propylene-styrene block copolymer. These elastomers may be used alone or in combination of two or more.

An antistatic property can be imparted to the above-mentioned polypropylene or the thermoplastic elastomer by adding a filler capable of imparting conductivity. By imparting the antistatic property, it is possible to prevent dust and dirt from adhering to the gasket and the frame in the manufacturing process of the framed gasket. Fillers that can impart conductivity include iron,
Conductive fillers such as metal powder and metal fiber such as stainless steel and aluminum, carbon black and carbon fiber, and antistatic agents such as polyalkylamine, alkyl sulfonate, quaternary ammonium chloride, and alkyl betaine can be used. . The amount of the filler added to the polypropylene or the thermoplastic elastomer is preferably such that the volume resistivity of the polypropylene or the thermoplastic elastomer when the filler is added is 1 × 10 ⁸ Ωcm or less. Further, when the frame is required to have an electromagnetic wave shielding property, it is preferable to set the volume resistance value to 1 × 10 ² Ωcm or less. In the case of a thermoplastic elastomer, JIS-A when a filler is added is used.
The hardness is preferably 80 degrees or less, particularly preferably 10 to 50 degrees. Further, in the above-mentioned polypropylene or the thermoplastic elastomer, as the reinforcing material, inorganic fibers such as glass fibers and carbon fibers, inorganic fillers such as mica and talc, whiskers such as potassium titanate, etc. do not impair the effects of the present invention. It can be added in a range.

[0010] The frame and the gasket are integrated by joining polypropylene or the like forming the frame with a thermoplastic elastomer forming the gasket, preferably by a two-color molding method or an insert molding method. In the two-color molding method, first, polypropylene and the like forming the frame is melt injection molded in a mold by a dedicated injection molding machine,
Next, after the molded product is solidified, a thermoplastic elastomer having excellent fusion property with polypropylene or the like is melt-injected and molded by a special injection molding machine, and a part of a frame made of the molded product of the polypropylene or the like is heated. By forming the gasket portion composed of the thermoplastic elastomer layer, a gasket with a frame in which polypropylene or the like and the thermoplastic elastomer layer formed on the surface thereof are integrally compounded is obtained. Such a two-color molding method has a high production efficiency and can produce a framed gasket at low cost. On the other hand, in the insert molding method, a frame having a predetermined shape is prepared by various known molding methods using polypropylene or the like in advance, and the frame is placed in a mold. Next, the thermoplastic elastomer is melt-injected and molded by an injection molding machine to form a thermoplastic elastomer layer on a part of the frame, thereby forming the frame and the thermoplastic elastomer formed on the part thereof. Are integrally combined to obtain a framed gasket.

The framed gasket of the present invention reduces the generation of gas contaminating a magnetic disk or the like during use of an electronic device by forming a frame with polypropylene or the like or lubricant that does not contain a lubricant. be able to. In addition, since polypropylene or the like is used as the material of the frame, and no metal material is used, a rust-proofing process is not required, and the weight can be reduced. It is possible to produce a frame with high precision and to recycle polypropylene and the like.

[0012]

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 of a framed gasket of the present invention as viewed from a sealing surface side. In FIG. 1, 1 is a frame, and 2 is a gasket. The dimensions of this framed gasket are 100mm x 70
mm. This framed gasket is as follows:
It was produced by a two-color molding method. As the polypropylene forming the frame 1, a polypropylene containing no lubricant [trade name: CF3001 manufactured by Chisso Corporation] is used, and the thermoplastic elastomer forming the gasket has a number average molecular weight of 10
100 parts by weight of SEPS having a styrene content of 30% by weight and a paraffinic oil having a kinematic viscosity at 40 ° C. of 380 mm ² / sec [manufactured by Idemitsu Kosan Co., Ltd., trade name: Diana Process Oil PW380, weight average molecular weight 750] ]
It was prepared by kneading 150 parts by weight and 12.5 parts by weight of the same polypropylene as above. The JIS-A hardness of this thermoplastic elastomer was 22 degrees. Using a DC60E5ASE machine manufactured by Nissei Plastic Industry Co., Ltd. as a molding machine, first, the above-mentioned polypropylene for a frame is melt-injected and molded into a mold under the conditions of a mold temperature of 40 ° C. and a resin temperature of 180 ° C. Mold temperature 40 ° C, resin temperature 230 ° C
The above-mentioned thermoplastic elastomer for gaskets was melt-injected and molded under the conditions described above to produce a gasket with a frame in which the frame and the gasket were integrated. When the gasket with the frame manufactured as described above was used in a hard disk drive of a computer, a failure considered to be caused by the generated gas did not occur for a long time, and sufficient sealing properties were maintained for a long time. .

Comparative Example 1 The procedure of Example 1 was repeated except that a polypropylene containing metal soap salt-based lubricant [EX6 manufactured by Nippon Polychem Co., Ltd.] was used as the polypropylene forming the frame 1. Similarly, a framed gasket was produced. Using the framed gasket thus produced in a hard disk drive of a computer, a durability test was performed.
A reading defect considered to be caused by the generated gas occurred. Example 2 Example 1 was repeated except that, as the polypropylene forming the frame, calcium stearate-containing polypropylene [manufactured by Nippon Polychem Co., Ltd., trade name: MA03] was subjected to heat treatment in an oven at 110 ° C. for 24 hours. Is
A framed gasket was produced in the same manner as in Example 1. When the gasket with the frame manufactured in this manner was used in a hard disk drive of a computer, a failure considered to be caused by the generated gas did not occur for a long time, and sufficient sealing properties were maintained for a long time. . Comparative Example 2 In Example 2, a calcium stearate-containing polypropylene [manufactured by Nippon Polychem Co., Ltd., trade name: MA03]
A framed gasket was produced in the same manner as in Example 2, except that was used without heat treatment. A durability test was performed using the gasket with the frame manufactured in this manner in a hard disk device of a computer. As a result, a reading defect considered to be caused by the generated gas occurred.

[0014]

According to the gasket of the present invention, the gas which contaminates a magnetic disk or the like is reduced when it is used in an electronic device, and the gasket is lightweight and has excellent sealing properties.

[Brief description of the drawings]

FIG. 1 is a perspective view of a framed gasket of the present invention as viewed from a sealing surface side.

[Explanation of symbols]

 1: Frame 2: Gasket

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3J040 AA01 AA12 AA17 CA01 EA15 EA17 EA25 FA06 HA01 HA15 4E360 AB12 AB33 ED22 EE03 FA08 GA22 GA29 GA53 GB99 GC08

Claims (9)

[Claims] 1. A gasket with a frame in which a frame and a gasket are integrated, wherein the frame is made of a propylene homopolymer and / or a propylene copolymer containing propylene as a main component without a lubricant, and the gasket is made of an elastic material. A gasket with a frame, wherein the gasket comprises a frame body and a gasket. 2. The method according to claim 1, wherein the propylene homopolymer and / or the propylene copolymer containing propylene as a main component does not contain an additive that generates gas at a temperature of 120 ° C. or lower. Gasket with frame. 3. The gasket with a frame according to claim 1, wherein the elastic body forming the gasket is a thermoplastic elastomer. 4. The method according to claim 1, wherein the unification is carried out by fusing a propylene homopolymer and / or a propylene copolymer mainly composed of propylene with the thermoplastic elastomer forming the gasket. 3. The gasket with a frame according to 3. 5. A gasket with a frame in which a frame and a gasket are integrated, wherein the frame is made of a heat-treated propylene homopolymer and / or a propylene copolymer mainly composed of propylene, and the gasket is made of an elastic material. A gasket with a frame, wherein the frame and the gasket are integrated. 6. The gasket with a frame according to claim 5, wherein the elastic body forming the gasket is a thermoplastic elastomer. 7. The method according to claim 1, wherein the integration is performed by fusing a propylene homopolymer and / or a propylene copolymer mainly composed of propylene forming the frame with a thermoplastic elastomer forming the gasket. 6. A gasket with a frame according to 6. 8. A method for manufacturing a gasket with a frame, comprising: integrating a frame and a gasket by a two-color molding method to manufacture the gasket with a frame according to any one of claims 1 to 7. 9. A method for manufacturing a gasket with a frame, comprising: integrating a frame and a gasket by an insert molding method to manufacture the gasket with a frame according to any one of claims 1 to 7.