PURPOSE: To seal liquid or gaseous chemicals by covering an elastic layer with a chemicals-resisting layer together with covering the chemicals-resisting layer with a fine-fiber-structured porous layer made of tetra-fluoroethylene resin.
CONSTITUTION: The sealing material is made up of a three-layered structure: an elastic body layer 1, a core part 1, a plastic layer 2, an intermediate layer, and a PTFE-made porous layer 3, the outer most layer. It is most appropriate to form the elastic layer 1 by using rubber material such as nitrile rubber, natural rubber, or silicone rubber. The plastic layer 2, which covers the elastic body 1, is formed by means of PE, PP, FEP, etc. In addition, the outermost PTFE-made porous layer 3 is made up of fine-fiber-structure formed by nodes, which are connected with each other by fibers. The mean diameter and porosity of the porous layer 3 is set at 0.1W10μm and 30W95%, respectively.