| 摘要 |
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°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 agent in addition to the unvulcanized rubber having a tc (90) value of 200 to 400 sec. |
