Polyurethane sandwich structure element and process for production thereof
AssigneeBayer Aktiengesellschaft
InventorsWolfgang Grimm, Heinz Hausmann, Hans Mandel, Ernst-Christoph Prolingheuer
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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.
Claims5
A process for producing self-supporting sandwich structure elements comprising applying at least one non-cellular polyurethane layer and at least one polyurethane foamed layer to a substrate, wherein mixtures which react to form each polyurethane layer are used which contain a polylether polyol with an OH number of 250 to 400, a semi-prepolymer based on MDI and polyether polyol and containing 20 to 30% by weight NCO, and optionally foaming agents, wherein the mixtures are reacted at an isocyanate index of from 90 to 130, wherein at least the non-cellular polyurethane layers have a content of 10 to 55% by weight of finely divided mica, and wherein the layers of the sandwich structure element are applied successively to a substrate, wherein the next layer is applied in each case before the layer situated below it has become tack-free.
Dependencies are inferred from the claim text.