| 摘要 |
A composite structure including a polyurea show surface, or top layer, and a polyurethane backing layer is disclosed. Preferably, the show surface of the composite structure is substantially free of volatile organic compounds and is aliphatic such that it is ultraviolet light stable. Specifically, the show surface is the reaction product of an aliphatic polyisocyanate or aliphatic polyisocyanate blend, and of a resin component which is a polyamine. The resin component reacts with the aliphatic polyisocyanate to form a polyurea. The show surface has a Shore D hardness of 70. Like the show surface, the polyurethane backing layer of the composite structure is substantially free of volatile organic compounds. This backing layer is the reaction product of a second polyisocyanate component, such as polymeric diphenylmethane diisocyanate, and of a second-layer resin component, which comprises a polyol having a functionality of at least three. The complete composite structure has a flexural modulus of at least 200,000 lb/in2.
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