| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject foam exhibiting excellent mechanical strength and dimensional stability, affording high expansion ratio, and useful as e.g. a cushioning material, thermal insulation material, electrical insulation material, by specifying the liquid crystal resin content ratio for the surface layer and internal layer at a specific relationship. SOLUTION: This foam has such structure as to have provided with a surface layer at least on one side of the internal layer, and is so designed that (A) a thermoplastic resin is blended with (B) a liquid crystal resin, wherein the content of the resin B in the surface layer is higher than that in the internal layer. This foam is obtained, for example, by the following method: the resin B, the resin A having the melting point lower than the transition point of the resin B, and a volatile foaming agent or inorganic gas are mixed together at a temperature higher than the transition point of the resin B in an extruder and the resulting blend is then extruded along with expansion from the extruder set at a temperature 6-50 deg.C higher than the transition point of the resin B. |
