Process for providing homogeneous copolymers of vinylpyrrolidone and 3-dimethylaminopropyl methacrylamide (DMAPMA) which form clear aqueous solutions having high cloud points
AssigneeISP Investments Inc.
InventorsYuanzhen Zhong, Philip F. Wolf
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Abstract
A process for making homogeneous copolymers of vinylpyrrolidone (VP) and 3-dimethylaminopropyl methacrylamide (DMAPMA) which form clear aqueous solutions having high cloud points. The process involves precharging VP and DMAPMA monomers in a predetermined ratio, and then feeding VP and DMAPMA at a predetermined rate, the ratio of the components in the initial charge and the feeding rates for the monomer being selected in accordance with the reactivity rates of the monomers towards copolymerization as opposed to homopolymerization.
Claims10
A process for making substantially homogeneous copolymers of vinylpyrrolidone and 3-dimethylaminopropyl methacrylamide having a selected weight ratio of 5:95 to 95:1 which form clear aqueous solutions having a high cloud point substantially in excess of room temperature by polymerization of the monomers in water, a water miscible organic solvent, and mixtures thereof, in the presence of a radical initiator, which comprises:
- (a) precharging a reactor with initial weight amounts of vinylpyrrolidone (f.sub.1) and of 3-dimethylaminopropyl methacrylamide (f.sub.2) monomers according to the equation ##EQU4## wherein f.sub.1 :
- mole fraction of monomer 1 in the feed;
- f.sub.2 :
- mole fraction of monomer 2 in the feed;
- F.sub.1 :
- mole fraction of monomer 1 in the copolymer;
- F.sub.2 :
- mole fraction of monomer 2 in the copolymer;
- r.sub.1 :
- reactivity ratio for monomer 1 and
- r.sub.2 :
- reactivity ratio for monomer 2;
- to provide said selected weight ratio of monomers, solvent and initiator, at a polymerization temperature, and
- (b) introducing separate feed streams of vinylpyrrolidone and 3-dimethylaminopropyl methacrylamide monomers, solvent and initiator into said reactor at given rates, according to the selected monomer ratio in said copolymer, over a given period of time.
Dependencies are inferred from the claim text.