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US 7,507,781 B2Granted
Anionic copolymers prepared in an inverse emulsion matrix
AssigneeHercules Incorporated
InventorsBrian Walchuk, Fushan Zhang, John C. Harrington, William Sean Carey, Richard Lee Brady
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Abstract
A papermaking method and a composition which utilize, as a drainage aid, a water-soluble anionic copolymer prepared via a water-in-oil polymerization technique that, absent a cross-linking agent, is characterized by a Huggins' constant (k′) determined in 0.01M NaCl greater than 0.75 and a storage modulus (G′) for a 1.5 wt. % actives polymer solution at 4.6 Hz greater than 175 Pa.
Claims15
A method of preparing a polymer by water-in-oil emulsion polymerization comprising:
- (a) preparing an oil phase comprising:
- at least one hydrocarbon;
- and a surfactant system wherein the surfactant system comprises at least one diblock or triblock surfactant to form an emulsion upon the addition of an aqueous phase;
- (b) preparing an aqueous phase comprising at least one ethylenically unsaturated anionic monomer and at least one ethylenically unsaturated anionic monomer and at least one ethylenically unsaturated nonionic monomer;
- (c) adding said aqueous phase (b) to said oil phase (c) to form an emulsion;
- and
- (d) causing the monomers in the emulsion to polymerize by free radical polymerization;
- wherein the diblock or triblock surfactant to monomer ratio is at least about 0.03 and the pH is adjusted to from about 2 to about 7 and wherein no additional crossing linking agent is added to the system, wherein the resulting polymer having a Huggins' constant (k′) determined between 0.0025 wt. % to 0.025 wt. % of said polymer in 0.01 m NaCl is greater than 0.75;
- and having a storage modulus (G′) for a 1.5 wt. % actives of said polymer solution at 4.6 Hz is greater tan 175 Pa.
6 more elements
Dependencies are inferred from the claim text.