Foamed thermoplastic resin molding for automotive interior and production method thereof

A method for producing a speaker grille-integrated foamed thermoplastic resin molding for automotive interior, the method using a mold, which can be opened and closed, comprising a pair of a female and male mold members, the mold having an opening hole-forming pin for forming an opening hole of the speaker grille and a slide core that can be moved forward and backward in the mold opening-and-closing direction, the mold having a structure capable of causing the female and male mold members to form a partial contact state by means of the opening hole-forming pin and the slide core and capable of freely controlling a mold cavity clearance defined by the female and male mold members while causing the slide core to move so as to maintain the contact state, wherein the process comprises the steps of:

• (a) charging a molten thermoplastic resin containing a foaming component into a mold cavity defined by the female and male mold members while causing the female and male mold members to form the partial contact state by means of the opening hole-forming pin and the slide core;
• (b) forming a solidified layer in a surface of the molten thermoplastic resin charged in the mold cavity;
• (c) opening, after the formation of the solidified layer, the mold in the molding thickness direction so that the mold cavity clearance becomes the thickness of a final molding while moving the slide core so as to maintain the contact state, thereby foaming an unsolidified portion of the molten thermoplastic resin charged;
• and
• (d) cooling a molding while maintaining the mold cavity clearance at the thickness of the final molding.