| 摘要 |
PROBLEM TO BE SOLVED: To provide a process for producing a foamed sheet that has a spindle- shaped foam of which the longitudinal axis is oriented to the thickness direction of the foamed sheet and that is excellent in compressive rigidity. SOLUTION: On at least one surface of a foamable sheet comprising a thermoplastic resin composition containing a heat decomposable, chemical foaming agent, a surface material that has a strength capable of inhibiting a foaming power directed inwardly from the surface and has a releasable surface is laminated so that the releasable surface of the surface material is directed in face-to- face relation with the foamable sheet, whereby a composite foamable sheet is obtained,. The composite foamable sheet is heated so as to cause the composite foamable sheet to foam. From the resultant composite foamed sheet, the surface material is released. As a thermoplastic resin composition, a modified polyolefin produced by melt mixing a polyolefin resin and at least one monomer for modification selected from a dioxime compound, a bismaleimide, a divinylbenzene and an acrylic multifunctional monomer is preferably used. |
