THERMOPLASTIC RESIN FOAM

摘要

Disclosed is a thermoplastic resin foam having high reflectance and good shape-retaining properties which is suitable for a backlight or illumination box of electrical advertising displays, illuminating devices, displays or the like. The thermoplastic resin foam is produced by a production method which comprises a step for having a resin sheet contain an inert gas by keeping the resin sheet, which is composed of a thermoplastic resin (A) and a thermoplastic resin (B) with a functional group having an affinity with the thermoplastic resin (A), in a pressurized inert gas atmosphere, and another step for causing the inert gas-containing resin sheet to foam by heating the resin sheet to a temperature not less than the softening temperature of the thermoplastic resin at the atmospheric pressure.