Inverse emulsions
AssigneeNational Starch and Chemical Corporation
InventorsYen-Jer Shih, John (Ji-Hsiung) Tsai, Wen B. Chiao, Dilip K. Ray-Chaudhuri
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Abstract
Polysaccharide graft copolymers are prepared by a water-in-oil emulsion polymerization process in which the polysaccharide and water-soluble monomer are emulsified in an oil phase containing emulsifying agents and polymerized therein. The resultant emulsion polymers are in stable form and may be used directly, for example, as adhesives for prepasted wallpaper, or may be inverted into aqueous systems and used for their thickening or flocculating properties.
Claims20
A water soluble or water swellable graft copolymer dispersed in an inverse water-in-oil emulsion comprising:
- (a) 20-80% by weight of the emulsion of an aqueous discontinuous phase comprising 30-70% by weight water and 70-30% by weight of a polysaccharide copolymer having a polysaccharide content of 5 to 50%;
- and
- (b) 80 to 20% by weight of a continuous phase comprising 70 to 99% inert hydrophobic liquid;
- and 1 to 30% by weight of an oil soluble surfactant.
A process for the preparation of an inverse water-in-oil emulsion of a water soluble or water swellable polysaccharide graft copolymer comprising the steps of:
- (a) forming an aqueous phase comprising 30-70% by weight water with a mixture of 70-30% by weight of a polysaccharide and a water soluble monomer wherein the polysaccharide comprises 5-50% by weight of said mixture;
- (b) adding thereto a solution comprising 70-99% inert hydrophobic liquid and 1-30% by weight of an oil soluble surfactant;
- (c) polymerizing the resultant blend to produce a stable water-in-oil emulsion which contains dispersed therein finely divided particles of a polysaccharide graft copolymer.
Dependencies are inferred from the claim text.