| 摘要 |
PURPOSE:To obtain a foam having a uniform cell diameter, a small compression set and good elasticity, by preparing a foamable composition of a crosslinked thermoplastic fluorocarbon resin and foaming this composition by heating to a specified expansion ratio. CONSTITUTION:A thermoplastic fluorocarbon resin is crosslinked and then mixed with a blowing agent or this resin is mixed with a blowing agent and then crosslinked to form a foamable composition. This composition is foamed by heating to an expansion ratio of at least 1.5. Said crosslinking is performed by adding a chemical crosslinking agent to the thermoplastic fluorocarbon resin and heating the mixture or by irradiating it with an ionizing radiation in an inert gas or water. Alternatively, a crosslinkable fluorocarbon resin containing units of a copolymerizable monomer having a crosslinking functional group is mixed with a low-molecular compound which can react with said functional group to form a crosslinkage, and the mixture is crosslinked by heating. |
