| 摘要 |
PURPOSE:To manufacture a styrene-based resin foamed thick sheet by a method wherein the surface of a foam, which has been produced by extruding and foaming styrene-based resin and specified foaming agent, is again heated up to within the specified temperature range. CONSTITUTION:The mixture of 5-20wt% of the sum of 0.3-1.5mol of dichlorotrifluoroethane and 1.5-0.3mol of monochlorodifluoromethane or 1.0-0.3mol of butane or their mixture as foaming agent with 1kg of styrene-based resin under kneading is extruded with an extruder so as to obtain a foamed sheet having a thickness of 10mm or more by cooling the surface of the sheet during or just after extrusion. After the surface just after extrusion is once cooled down below the thermal deformation temperature of the resin. In succes sion or after leaving as it is, the surface is again heated up to a temperature, which is higher than the thermal deformation temperature by 5-70 deg.C, for foaming. |
