METHOD FOR PRODUCING POLYAMIDE MOLDING

• Main Author: MUNESAWA YUJI
• Format: Patent
• Language: English
• Published: 04.11.2004
• Edition: 7
• Subjects: AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; 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

PROBLEM TO BE SOLVED: To provide a method for producing a molding of a semi-aromatic polyamide comprising dicarboxylic acid units mainly composed of a terephthalic acid unit and diamine units mainly composed of a 6-18C aliphatic alkylenediamine unit in good productivity without being accompanied by a problem of the occurrence of a gate trace projection by defective cutting in the opening of a submarine gate and resin waste. SOLUTION: An injection-molded article is molded by injecting the semi-aromatic polyamide from the opening of the submarine gate into a cavity formed between molds. When the molds are opened, the molding is demolded by an ejector pin, and simultaneously the molding and a submarine gate part are cut and separated. The incident angle of the submarine gate is set up at 45-65° with a parting surface made a standard, and the tip part of the submarine gate is formed in the shape of a spherical surface or an elliptic spherical surface. The relationship between its curvature radius R and the diameter of the opening of the submarine gate is R≥ . The opening does not exist on the extension of the center line of the submarine gate. COPYRIGHT: (C)2005,JPO&NCIPI