| 摘要 |
PURPOSE: To provide a method for preparing in extruded foamed polycarbonate resin sheet with high closed-cell ratio and excellent appearance, heat insulating properties, moldability, etc. CONSTITUTION: A polycarbonate resin foamed sheet is prepd. by performing extrusion foaming of a polycarbonate resin (a branched polycarbonate resin or a mixture of a branched polycarbonate resin and another polycarbonate resin) with a structural viscosity index (N value) of at least 1.1 which can be obtd. from the following equation by changing the pressure condition to 20-300kg/cm<2> at the temp. condition of 300 deg.C. Log Q=N.logP+K (wherein Q: flow rate of the molten resin [cc/sec], N: the structural viscosity index (N value), P: pressure [kg/cm<2> ], K: const. for each polycarbonate resin). |
