| abstract |
A thermoplastic resin foam which has both high reflectance and superior shape-retention properties, suitable for use in backlights and illumination boxes for illumination signboards, lighting fixtures, displays and the like. The thermoplastic resin foam is manufactured by a manufacturing method including a procedure for holding a resin sheet composed of thermoplastic resin (A) and thermoplastic resin (B), which has a functional group having an affinyty with thermoplastic resin (A), within a pressurized inert gas atmosphere to enable the resin sheet to contain inert gas, and a procedure for foaming by heating the resin sheet containing inert gas at a temperature higher than the softening temperature of thermoplastic resin, under normal pressure. |