| 摘要 |
<p>The present invention is directed to an improved internal mold release system for the production of high density molded SRIM parts, i.e. molded parts having a density of from 1.3 to 2.0 g/cc. In particular, the process comprises reacting a reaction mixture comprising an organic polyisocyanate and at least one organic compound containing isocyanate-reactive hydrogens in the presence of a catalyst and an internal mold release agent in a closed mold. The internal mold release agent is a compound corresponding to the formula: <CHEM> wherein R<2> represents hydrogen, the group R<5>-NH-CO-, or a C1 to C24 alkyl or substituted alkyl group, a C3 to C24 cycloalkyl or substituted cycloalkyl group, a C2 to C24 alkenyl or substituted alkenyl group, or a C6 to C24 aryl or substituted aryl group, and wherein R<1>, R<3>, R<4> and R<5> may be the same or different and represent a C1 to C24 alkyl or substituted alkyl group, a C3 to C24 cycloalkyl or substituted cycloalkyl group, a C2 to C24 alkenyl or substituted alkenyl group, or a C6 to C24 aryl or substituted aryl group, with the proviso that at least one of R<1>, R<2>, R<3>, R<4> and R<5> is a C12 to C24 alkyl or substituted alkyl group, or a C12 to C24 alkenyl or substituted alkenyl group, and with the further proviso that substituent groups are inert toward isocyanate groups at temperatures of 100 DEG C or less.</p> |
