Resin multilayer molding method and multilayer molding device

Abstract

A resin multilayer molding method in which a skin material having a resin decorating layer on a surface and a core-material resin are integrally molded in a mold, comprising the steps of: presetting a relationship of a glass transition point (Tgs) of the resin decorating layer of the skin material and a supply temperature (Tc) of a molten resin forming a core material to satisfy Tgs<Tc, and performing molding on a condition that a maximum temperature (Tsm) of the resin decorating layer of the skin material during clamping satisfies Tsm>Tgs. When a temperature of the resin decorating layer of the skin material reaches a previously estimated and set value (Tsd) so that a temperature Tsc, which temperature of the resin decorating layer reaches by rising again after an air insulating layer is formed, satisfies Tsc≧Tgs on the basis of a correlation between a temperature of the core-material resin during clamping and forming and retaining the air insulating layer and a temperature of the skin material decorating layer, the gap is made between the resin decorating layer of the skin material and the mold cavity surface opposed to the resin decorating layer to form and retain the air insulating layer. By this, remarkably high-quality resin multilayer molded products can be stably supplied at low cost without impairing surface decorating performance.