Mold cleaning rubber compositon

• Main Authors: SUNAGO, OSAMU, HIROMITSU, KIYOHITO, NOMURA, HIROAKI
• Format: Patent
• Language: Chinese; English
• Published: 16.07.2009
• Subjects: AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; CHEMISTRY; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; 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; USE OF INORGANIC OR NON-MACROMOLECULAR ORGANIC SUBSTANCES ASCOMPOUNDING INGREDIENTS; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

This invention provides a mold cleaning rubber composition for removing soiling on the surface of a mold produced in a curable resin molding process. An unvulcanized rubber is used as a base material resin. The unvulcanied rubber comprises an ethylene-propylene rubber and a butadiene rubber at a mixing ratio of 90/10 to 50/50 on the basis of parts by weight. After the vulcanization curing of the unvulcanized rubber, the elongation is 80 to 800%, the tensile strength is 3 to 10 MPa, and the rubber hardness (durometer hardness) is A60 to 95. The 90% vulcanization time (proper vulcanization point) tc (90) at a mold temperature of 175 DEG C is 50 to 100 sec or 200 to 400 sec. When the mold cleaning rubber composition is used for cleaning for molds for the production of small-size packages having a large cavity depth, for example, PDIP or SOIC, and molds for the production of small packages, particularly small packages with a small number of pins, preferably, the mold cleaning rubber composition contains a release