Thermoplastic polyether polyurethane elastomers
AssigneeUnion Carbide Corporation
InventorsRichard J. Zdrahala, Frank E. Critchfield
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Abstract
Thermoplastic polyether polyurethane elastomers are provided by reacting and forming: (a) a novel liquid polyurethane quasi-prepolymer having a free NCO content of from about 16 percent to about 25 percent; (b) a reactive poly(oxypropylene-oxyethylene) diol; and (c) as an extender, a short chain diol in the presence of (d) a catalyst. The elastomers can be either solid or microcellular, and they are suitable for production using Reaction Injection Molding (RIM) or conventional casting technology. The elastomers are useful in the production of automotive body panels, gears, seals and the like, and, since the elastomers are thermoplastic, any excess elastomer ("scrap") can be reused.
Claims36
A process for producing a solid or microcellular polyether polyurethane elastomer which comprises reacting a reaction mixture containing:
- (a) a liquid polyurethane quasi-prepolymer having a free NCO content of from about 16 percent to about 25 percent in an amount that provides from 0.8 to 1.1 isocyanato groups per active hydrogen group in the reaction mixture, produced by reacting a poly(oxypropylene-oxyethylene)diol having a molecular weight of at least 500 with an aromatic diisocyanate,
- (b) a poly(oxypropylene-oxyethylene) diol having a molecular weight of at least 1000, having terminal oxyethylene groups, and having a primary hydroxyl content of at least 50 mole percent,
- (c) from 5 to 75 parts by weight of a diol extender selected from the group consisting of short-chain alkane diols and short-chain oxyalkylene glycols per 95 to 25 parts by weight of (b), and
- (d) a catalytic amount of catalyst for curing
- the reaction mixture to produce the elastomer.
A liquid polyurethane quasi-prepolymer having a free NCO content of from about 16 percent to about 25 percent that is produced by reacting a poly(oxypropyleneoxyethylene) diol having a molecular weight of at least 500 with an aromatic diisocyanate.
The quasi-prepolymer of claim 37 wherein the aromatic diisocyanate is 4,4'-diphenylmethane diisocyanate.
Dependencies are inferred from the claim text.