PRODUCTION OF OLEFIN-BASED THERMOPLASTIC ELASTOMER INJECTION MOLDED FOAMED BODY

• Main Authors: YOSHINO SHOJI, TSUJI TATSUMI, YAJIMA KAZUO, TERADA MASAHIRO, KAMAE KOSUKE, MATSUOKA KENJI, OGAWA TOME
• Format: Patent
• Language: English
• Published: 17.06.1997
• Edition: 6
• Subjects: AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F,C08G; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; CHEMISTRY; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; GENERAL PROCESSES OF COMPOUNDING; INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; PERFORMING OPERATIONS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; THEIR PREPARATION OR CHEMICAL WORKING-UP; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL; WORKING-UP

PROBLEM TO BE SOLVED: To obtain the subject foamed body which is highly expanded, having uniform and dense foam, exhibiting good soft feeling and useful as an interior part for automobiles by injecting an olefinic thermoplastic elastomer having a specific composition and properly operating the cavity volume. SOLUTION: An elastomer comprising (A) 100 pts.wt. olefinic thermoplastic elastomer obtained by dynamically heat-treating (i) 25-70wt.% ethylene-propylene- diene terpolymer rubber containing an ethylene-propylene-diene terpolymer rubber having 340-385 Mooeny viscosity and 2-6 ratio of weight-average molecular weight Mw to number-average molecular weight and a mineral oil-based softening agent in an amount of 45-150 pts.wt. based on 100 pts.wt. ethylene- propylene-diene terpolymer, (ii) 15-5wt.% polyisobutylene and/or isobutylene- isoprene copolymer rubber and (iii) 60-25wt.% propylene-α-olefin copolymer resin having 2-20wt.% α-olefin content, 0.1-10g/10min melt flow rate and 3-10 Mw/Mn in the presence of an organic peroxide and (B) 1-10 pts.wt. foaming agent is injected and subjected to expansion molding.