Process of increasing the molecular weight of water soluble acrylate polymers by chain combination
AssigneeRohm and Haas Company
InventorsKathleen A. Hughes, Graham Swift
Life of this patent
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Abstract
A method has been discovered for generating free radicals at saturated carbon atoms on the backbone of acrylate polymers or copolymers. This method is useful for combining at least two polymer chains at the free radical sites on each polymer chain to form a polymer or copolymer product with increased molecular weight and a controlled degree of branching. The polymers and copolymers produced by this process are useful as antiscalants, dispersants, incrustation inhibitors and superabsorbants. They are particularly useful in detergent and cleaning applications.
Claims15
A method of increasing molecular weight comprising:
- a) forming an aqueous solution containing at least two water soluble polymer chains, wherein at least one of the water soluble polymer chains is a water soluble acrylate polymer;
- b) adjusting and maintaining the aqueous solution pH from about 1 to about 11;
- c) gradually feeding one or more water soluble initiators to the aqueous solution and generating one or more free radicals at saturated carbon atoms on at least two of the water soluble polymer chains, at least one of the water soluble polymer chains being the acrylate polymer;
- wherein when the aqueous solution pH is in the range of from about 3 to 7, the total concentration of the one or more water soluble initiators is from about 0.5 to 5 weight percent, based on the weight of the water soluble acrylate polymer;
- and
- d) combining the acrylate polymer chain with one or more of the water soluble polymer chains at the free radical sites to form a water soluble polymer product with a predetermined weight average molecular weight equal to or less than about 142,000, and wherein the molecular weight of the polymer product is greater than the acrylate polymer.
Dependencies are inferred from the claim text.