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US 6,475,412 B1Granted
Process for making polyurethaneurea powder
AssigneeE. I. du Pont de Nmeours and Company
InventorDavid Herbert Roach
Life of this patent
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Abstract
Polyurethaneurea powders, prepared from spandex under specific process conditions, are provided.
Claims8
A process for making a polyurethaneurea powder comprising the steps of:
- feeding a polyurethaneurea-based spandex to an extruder having at least one heating zone at a rate less than the maximum feed rate of the extruder;
- and
- extruding the spandex so that it is subjected to an average temperature range and a total residence time range such that the polyurethaneurea is not degraded and the powder is formed.
Dependencies are inferred from the claim text.