Method for producing molded gasket
In a method for producing a molded gasket having a surface treated layer on one surface of a substrate and integrally formed with a gasket body constructed by a rubber-like elastic body on the other surface, a first step of integrally molding the gasket body on the substrate, a second step of temporarily placing the molded piece on a placement stand, and a third step of removing a burr portion from a production portion by punching the molded piece are sequentially executed. For preventing foreign material attachment, pollution and scratching, the first step integrally forms a projecting leg portion constructed by a rubber-like elastic body at a position corresponding to the burr portion in the molded piece, the second step brings the molded piece into contact with the placement stand by the leg portion, and the third step removes the leg portion as a part of the burr portion.
1. A method for producing a molded gasket which is provided with a surface treated layer on one surface in a thickness direction of a substrate and is structured such that a gasket body constructed by an elastic body is integrally formed on the other surface in the thickness direction, comprising:
a first step of integrally molding said gasket body on said substrate which is provided with said surface treated layer;
a second step of temporarily placing the molded piece finishing said first step on a placement stand;
a third step of removing a burr portion in a peripheral edge from a production portion by punching the molded piece finishing said second step; and
sequentially executing the first step, the second step and the third step,
wherein said first step integrally forms a projecting leg portion constructed by an elastic body at a position corresponding to said burr portion in said molded piece, said second step brings said molded piece into contact with said placement stand by said leg portion, and said third step removes said leg portion as a part of said burr portion.
2. The producing method according to claim 1 , wherein said leg portion is integrally molded on the other surface in the thickness direction on said substrate in the same manner as said gasket body, and said leg portion is formed in such a manner that a height dimension thereof becomes larger than that of said gasket body.
3. The producing method according to claim 2 , wherein said leg portion and said gasket body are integrally molded via a rubber impregnated portion which is impregnated with a porous structure provided in said substrate.
4. The producing method according to claim 1 , wherein said leg portion is integrally molded on the one surface in the thickness direction which is provided with said surface treated layer in said substrate in contradiction to said gasket body.
5. The producing method according to claim 4 , wherein said leg portion and said gasket body are integrally formed via a rubber impregnated portion which is impregnated with a porous structure provided in said substrate, and a rubber filled portion which is filled in a through hole provided on said surface treated layer.
6. The producing method according to claim 4 , wherein said leg portion and said gasket body are integrally molded via a rubber impregnated portion which is impregnated with a porous structure provided in said substrate, and a rubber impregnated portion which is impregnated with a porous structure provided in said surface treated layer.
7. The producing method according to claim 1 , wherein said first to third steps are sequentially executed in a state in which said surface treated layer is coated with a protection film so as to protect said surface treated layer.
8. The producing method according to claim 7 , wherein said leg portion is integrally formed on the one surface in the thickness direction which is provided with said surface treated layer in said substrate in contradiction to said gasket body, and said leg portion and said gasket body are integrally formed via a rubber impregnated portion which is impregnated with a porous structure provided in said substrate, a rubber impregnated portion which is impregnated with a porous structure provided in said surface treated layer, and a rubber filled portion which is filled in a through hole provided in said protection film.
9. The producing method according to claim 7 , wherein said leg portion is integrally formed with the one surface in the thickness direction which is provided with said surface treated layer in said substrate in contradiction to said gasket body, and said leg portion and said gasket body are integrally formed via a rubber impregnated portion which is impregnated with a porous structure provided in said substrate, a rubber filled portion which is filled in a through hole provided in said surface treated layer, and a rubber filled portion which is filled in a through hole provided in said protection film.
10. The producing method according to claim 7 , wherein said protection film is constrained only by a part of said leg portion in place of all of said leg portion, so as to prevent deflection from being generated at a time of thermal expansion while taking into consideration difference in coefficient of thermal expansion between said protection film and said substrate.
11. The producing method according to claim 8 , wherein said protection film is constrained only by a part of said leg portion in place of all of said leg portion, so as to prevent deflection from being generated at a time of thermal expansion while taking into consideration difference in coefficient of thermal expansion between said protection film and said substrate.
12. The producing method according to claim 9 , wherein said protection film is constrained only by a part of said leg portion in place of all of said leg portion, so as to prevent deflection from being generated at a time of thermal expansion while taking into consideration difference in coefficient of thermal expansion between said protection film and said substrate.
13. The producing method according to claim 1 , wherein said substrate is a GDL in a fuel battery cell, and said surface treated layer is an MPL layer.