| 摘要 |
PURPOSE:To obtain a millable urethane rubber with a low hardness without adding a plasticizer, which rubber will provide a polyurethane molded item without inclusion of bubbles, by adding a cast type urethane rubber, hardening it, and adding organic peroxides, etc. followed by the hardening. CONSTITUTION:A millable urethane rubber (comprising a composition composed of a polyester and a polyether) is milled by rolls, and a cast type polyurethane rubber (a compound of a polyester with an isocyanate) and a hardener (e.g. 3,3'- dichloro-4,4'-diaminodiphenyl methane, or the like) are added thereto. After the milling, a peroxide (e.g. dihloro-peroxides, or the like) is incorporated, and the mixture is heated and vulcanized to produce the aimed urethane rubber molded item free from any bubbles. |
