| 摘要 |
PURPOSE:To shorten the sweeping time of a mold and, at the same time, obtain excellent sweeping effect by a method wherein a sweeping composition is employed, which contains respectively specified amounts of amino alcohol-based compound, surface-active agent, organic peroxide and white carbon on the basis of ethylene prppylene-based rubber stock and, at the same time, has the specified curing speed and the specified after-cure hardness. CONSTITUTION:Mixture prepared by adding 10-50 pts.wt. of amino alcohol-based compound, the melting point of which is 100 deg.C or lower and the boiling point of which is 150 deg.C or higher, 1-10 pts.wt. of nonionic surface-active agent, the HLB value of which is 5-15 and the molecule of which has polyoxyethylene chain, 10-70 pts.wt. of white carbon, 10-60 pts.wt. of process oil, stearic acid and the like to 100 pts.wt of EPR stock is kneaded for several minutes in a pressurizing type kneader so as to be heated up to 100-120 deg.C. Then, 1-8 pts.wt. of organic peroxide is added thereto and dispersed, the resultant mixture is taken out in order to obtain mold sweeping composition. In addition, the curing speed of the composition at 170 deg.C measured with a curelastmeter of the obtained composition is 4-8min in T90 value. The hardness by JIS of the rubber-like matter after the vulcanization of the obtained composition is 20-70. |
