Abstract: For the production of sandwich structure elements comprising non-cellular polyurethane layers and polyurethane foamed layers which are produced on a substrate by the application of layers to a substrate, it is proposed that at least the non-cellular polyurethane layers contain 15 to 55% by weight of mica. Sandwich structure elements are obtained which are particularly dimensionally accurate and which adhere well. The effect is believed to be based on a non-homogeneous curing reaction of the mixture which reacts to form polyurethane, due to the presence of mica.

Abstract: The present invention relates to a process for the preparation of a cellular polyurethane by the reaction of(A) a polyisocyanate with(B) an isocyanate reactive component containing(1) at least one component having a molecular weight of about 60-2000 and a functionality of 2 to 8, containing isocyanate reactive groups,(2) optionally at least one component having a molecular weight of about 2000 to 12,000 and a functionality of 2 to 8 containing isocyanate reactive groups.(3) about 0.1 to 30 parts, based on 100 parts of (B1)+(B2), of a liquid adduct of an amine and carbon dioxide, and(4) optionally water, blowing agents, foam stabilizers, catalysts and other auxiliary agents and additives,characterized in that the liquid adduct of amine and carbon dioxide is liquid at 20.degree. C., optionally contains water, and is an adduct of carbon dioxide and an amine having at least one amino group and containing at least one primary, secondary or tertiary hydroxyl group, which amine may be solid or liquid at 20.degree.