METHOD FOR PRODUCING POLYPROPYLENE RESIN ARTICLE HAVING SKINMATERIAL LINED WITH FOAMED LAYER

• Main Authors: MATSUMOTO, MASAHITO, USUI, NOBUHIRO, MATUBARA, SHIGEYOSHI, HARA, TAKAHISA
• Format: Patent
• Language: English; French
• Published: 19.02.2002
• Edition: 5
• Subjects: AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS; LAYERED PRODUCTS; LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT ORNON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM; PERFORMING OPERATIONS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

The present invention provides a multi-layer molded article which is made of a polypropylene resin body and a skin material lined with a foamed layer. The article has a good appearance and is produced using upper and lower molds which have a cavity therebetween. A specific cavity clearance is freely set between the molds, a skin material lined with a foamed layer is placed between the upper and lower molds, and a molten polypropylene resin containing a chemical blowing agent is supplied through a resin melt conduit into the lower mold when the cavity clearance (t) is between (C + 15) mm and (C + 50) mm where "C" is a thickness of the skin material lined with the foamed layer, lowering the upper mold at a specific rate and pressing the molten resin at specific pressure to fill the cavity with the molten resin to complete molding of a body of the resin, pressing the body for a certain time after completing molding to form a skin layer, lifting up the upper mold to decrease compression pressure of the skin material lined with the foamed layer to a pressure lower than a blowing pressure of the polypropylene resin to form and solidify a foamed body, and again lowering the upper mold to apply a certain pressure on a molded article and cooling the article in the molds.