Polyurethane/epoxy resin cast mouldings prepn - by heating, mixing, casting and hardening

摘要

Mouldings are prepd. from a casting compsn. by mixing and heating a polyurethane, an epoxide resin and a cross-linking agent to 100 degrees C; casting in a mould preheated to 100 degrees C and hardening for >=5 hrs. at 140 degrees C. The casting compsns. comprises 23-59% polyurethane (esp. from polytetramethyleneglycol and TDI), 25-55% epoxy resin (esp. from bisphenol A and epichlorohydrin) and 16-22% cross-linking agent (esp. 4,4'-methylene-bis-(2-chloroaniline)); esp. 23% polyurethane and 55% epoxy resin or 59% polyurethane and 25% epoxy resin or linear interpolated intermediate valves thereof. This is a division of P 1900562.0. The process is used to mfr. elements for water acoustics. The mould may also be used for acoustic windows which are permeable to water resonance.