| 摘要 |
A process of reaction injection molding of polyurethanes is disclosed which includes the mixing of one or more of each of polyols, isocyanates, and catalysts, the reaction of the foregoing ingredients, and the molding and curing of the foregoing mixture into the desired configuration, the improvement comprising mixing with the other ingredients a silicone selected from the group consisting of Z4-aSiGa and R3-dGdSiO(Y2-bGbSiO)nSiGcX3-c wherein Z, R, Y, and X are selected from the group consisting of hydrogen, substituted and unsubstituted hydrocarbon radicals, and mixtures thereof; G is a radical of the structure -D(OR'')mOH wherein D and R'' are selected from the group consisting of substituted and unsubstituted hydrocarbon radicals, and m has a value of 1 to 50; a has a value of 1 to 4; d and c have values of 0 to 3, and b has a value of 0 to 2 wherein d, c, or b has a value of at least 1; and n has a value of 0 to 350. The incorporation of this composition aids in the release of the molded parts, shortens the molding cycle time, and, in the reaction injection molding process of polyurethanes, allows a two-stream process.
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