| 摘要 |
<p>PURPOSE: To improve the chemical resistance, the heat resistance, to improve hermetical sealability and to improve the bendability and stain resistance of the inner surface by laminating two layers of polyfluoroethylene (PTFE) having different structures, forming a third layer of a polymer material having higher elasticity, and setting the gas permeability of the third layer to a predetermined value or less. CONSTITUTION: A first layer 10 made of PTFE having a solid structure and a second layer 11' made of PTFE having a porous structure on the outer periphery are laminated. Further, a third layer is formed of a polymer material having permeability and higher elasticity than that of the material of the layer 11', i.e., elastomer such as synthetic rubber or natural rubber. In this case, the layer 10 and the layer 11' are integrated by thermal fusion bonding. The permeability of the layer 19' is so set as to become 100000sec or less of Gurley number. The layers 10 and 11' are integrated via an adhesive layer of thermoplastic fluorine resin, and the permeability of the layer 19' is set to 100,000sec or shorter of Gurley number.</p> |
