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US 5,328,972 AGranted
Process for preparing low molecular weight polymers
AssigneeRohm and Haas Company
InventorsEmmanuel A. Dada, Willie Lau, Richard F. Merritt, Yi H. Paik, Graham Swift
Life of this patent
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Abstract
A process for preparing polymers having molecular weights below 5,000 and polydispersity below 2.5 is provided. The polymerization is conducted in supercritical carbon dioxide at temperatures of at least 200.degree. C. and pressures above 3,500 psi. The process can be continuous, semi-continuous, or batch. The polymers are useful as detergent additives, scale inhibitors, dispersants and crystal growth modifiers.
Claims17
A process for preparing polymers having weight average molecular weights below 5,000 comprising:
- (a) forming a reaction mixture of one or more polymerizable monomers, and a free-radical initiator in supercritical carbon dioxide at an elevated temperature of at least 200.degree. C. and an elevated pressure of at least about 3,500 psi such that the one or more monomers are present in the reaction mixture at level of below 20 percent by weight of the supercritical carbon dioxide;
- and
- (b) maintaining the reaction mixture at said elevated temperature to form a polymer product.
Dependencies are inferred from the claim text.