Method of manufacturing plastic molding
AssigneeInoue MTP Kabushiki Kaisha
InventorsTohru Mayumi, Isamu Eto
Life of this patent
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Abstract
A method of manufacturing a plastic molding of a foamable thermoplastic raw material blank or preform which contains a foaming agent by high frequency voltage heating in a molding die assembly defining a molding cavity, wherein gas discharging openings which extend through the thickness of the blank or preform are preformed in the raw material blank or preform.
Claims9
A method of manufacturing a foamed plastic molding having a predetermined shape and formed from a foamable plastic raw material blank or preform containing a foaming agent comprising placing a foamable thermoplastic resin blank or preform having preformed gas discharge openings provided therein, the gas discharge openings extending through the thickness of the blank or preform, into the mold cavity a molding die assembly defining a molding cavity having the predetermined shape of the foamed plastic molding;
- the heating said black or preform by the application of high frequency voltage to soften and foam said blanks or preform and, wherein air originally trapped in the mold cavity and gas issued during the foaming is discharged from the mold cavity through said gas discharge openings preformed in the blank or preform which extend through the thickness of the raw material from the lower side thereof that is adjacent to the lower surface of the molding cavity to the opposite upper side of the foamable plastic raw material blank or preform.
Dependencies are inferred from the claim text.