| 摘要 |
PURPOSE:To manufacture a large-sized silicone rubber board as well as a strain-free thin silicone rubber sheet by a method wherein stock is injected outside a mold and then it is, carried within the mold for forming and, at the same time, the used stock has the fluidity showing the slump after five minutes of 30mm or less. CONSTITUTION:Liquid silicone used as stock is KE 1978 A/B, in which A represents that hardener is added and B represents that major agent is two-pack addition vulcanization type one and which has the slump after five minutes of 20mm. A preform 2A made of KE 1978 A/B is injected on continuous sandblasted PET film 3 as conveying carrier and then conveyed in molds 4A and 4B so as to be formed by clamping the molds. For example, the mold temperature is set to be 130 deg.C. Since KE 1978 A/B hardens in 20sec at 130 deg.C, the molds 4A and 4B are opened after 20sec so as to take a formed rubber board 7 out of the molds. During the mold clamping, a preform 2B in next cycle is injected. Simultaneously with the taking-out of said formed rubber board 7, the preform 2B is conveyed in the molds 4A and 4B. Thus, the structure of the molds is simplified and no removal of a runner from a formed article becomes necessary and, in addition, the forming of a large-sized rubber board becomes also easy. |
