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US 5,008,363 AGranted
Low temperature active aliphatic aromatic polycarbodiimides
AssigneeUnion Carbide Chemicals & Plastics Technology Corporation
InventorsCharles B. Mallon, Howard Chu
Life of this patent
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Abstract
A mixed aliphatic/aromatic polycarbodiimide prepared by first polymerizing an aliphatic isocyanate or mixture thereof, optionally in the presence of a polyfunctional isocyanate; arresting polymer chain growth by reaction with a stoichiometrically deficient amount of a monofunctional isocyanate-reactive compound, followed by further polymerization with an aromatic diisocyanate.
Claims20
A method for preparing a mixed aliphatic/aromatic polycarbodiimide comprising:
- (a) polymerizing a saturated aliphatic diisocyanate or a saturated cycloaliphatic diisocyanate or a mixture thereof, optionally containing a polyfunctional isocyanate, in the presence of a polycarbodiimide polymerization catalyst to form a polycarbodiimide intermediate having free isocyanate groups;
- (b) reacting said polycarbodiimide intermediate with a monofunctional isocyanate-reactive compound or a mixture thereof in an amount insufficient to react with all of said free isocyanate groups, and
- (c) further polymerizing said polycarbodiimide intermediate in the presence of an aromatic diisocyanate and said catalyst under polycarbodiimide-forming conditions until essentially all of the isocyanate groups are depleted.
A storage stable mixed aliphatic/aromatic polycarbodiimide prepared by
- (a) polymerizing a saturated aliphatic diisocyanate, or a saturated cycloaliphatic diisocyanate or a mixture thereof, optionally containing a polyfunctional isocyanate, in the presence of a polycarbodiimide polymerization catalyst to form a polycarbodiimide intermediate having free isocyanate groups,
- (b) reacting said polycarbodiimide intermediate with a monofunctional isocyanate-reactive compound or mixture thereof in an amount insufficient to react with all of said free isocyanate groups, and
- (c) further reacting said polycarbodiimide intermediate in the presence of an aromatic diisocyanate and said catalyst under carbodiimide-forming conditions until essentially all of the isocyanate groups are depleted.
Dependencies are inferred from the claim text.