| abstract |
Mo3503 LeA 27,404 A PROCESS FOR THE PREPARATION OF PLASTIC MOLDINGS ABSTRACT OF THE DISCLOSURE The invention relates to the preparation of plastic moldings by curing reactive, liquid casting compositions at elevated temperatures using a process in which (1) a liquid casting composition is prepared by reacting (a) an organic polyisocyanate, and (b) an organic compound containing at least two epoxide groups in a quantity corresponding to an equivalent ratio of isocyanate groups to epoxide groups of about 1.2:1 to about 500:1, in the presence of (d) a stabilizing alkylating sulfonic acid alkyl ester, methyl iodide, or dimethyl sulfate, (e) a latent, heat-activatable catalyst (preferably a tertiary or quaternary ammonium salt of an alkylating or acidic ester of organic phosphonic acids or phosphoric acid and/or an addition complex of boron trihalides with tertiary amines), and (f) optional auxiliaries and/or additives; (2) the liquid casting composition is transferred under pressure through a conduit into a heated mold having a temperature above 70°C; and (3) the casting composition is kept in the mold under pressure until curing is complete. Mo3503 |