Polyurethane foams
AssigneeImperial Chemical Industries PLC
InventorsStefan E. L. Helsemans, Gerhard Bleys
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Abstract
A method for the preparation of shape memory polyurethane foams by reacting a polyisocyanate component and a polyol composition in the presence of a foaming agent comprising water wherein the polyisocyanate component contains at least 85% by weight of 4,4'-diphenylmethane diisocyanate or a variant thereof and the polyol composition comprises at least one polyoxyalkylene polyol containing oxyethylene residues, said polyol composition having an average nominal hydroxyl functionality of from 2.2 to 6, an average oxyethylene content of at least 86% by weight and an average hydroxyl equivalent weight from 250 to 1500.
Claims8
A method for the preparation of shape memory polyurethane foams by reacting a polyisocyanate component and a polyol composition in the presence of a foaming agent comprising water wherein the polyisocyanate component contains at least 70% by weight of 4,4'-diphenylmethane diisocyanate or a variant thereof and the polyol composition comprises at least one polyoxyalkylene polyol containing oxyethylene residues, said polyol composition having an average nominal hydroxyl functionality of from 2.2 to 6, an average oxyethylene content of at least 86% by weight and an average hydroxyl equivalent weight from 250 to 1500 and wherein the amount of water is 1.5-6% by weight based on the weight of the polyol composition and wherein the isocyanate index is 90-150.
A reaction system comprising:
- (i) a polyisocyanate component containing at least 70% by weight of 4,4'-diphenylmethane diisocyanate or a variant thereof;
- (ii) a polyol composition comprising at least one polyoxyalkylene polyol containing oxyethylene residues, said polyol composition having an average nominal hydroxyl functionality of from 2.2 to 6, an average hydroxyl equivalent weight of from 250 to 1500 and an average oxyethylene content of at least 86% by weight;
- (iii) a foaming agent comprising 1.5-6% by weight of water based on the weight of the polyol composition, and, optionally,
- (iv) one or more additives conventional to foam formulations, the relative amounts of polyisocyanates and isocyanate-reactive compounds being such that the isocyanate index is 90-150.
Dependencies are inferred from the claim text.