Cross-linked, water-swellable polymer microgels
Patent 4172066 Issued on October 23, 1979. Estimated Expiration Date: 
September 26, 1997. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
September 26, 1997. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References RE26934 2205355 2982749 3104231 3247171 3252904 3284393 3539535 Cross-linked water-swellable polymer particles Patent #: 4059552 InventorsApplicationNo. 05/836875 filed on 09/26/1977US Classes:523/223, Process of forming a composition of a spheroidal material having physical dimension or composition containing same166/275, Injected fluid comprises water and material other than inorganic gas507/120, Nitrogen is attached directly or indirectly to the acrylic acid monomer or derivative by nonionic bonding (e.g., acrylamide, acrylonitrile, etc.)507/225, Nitrogen is attached directly or indirectly to the acrylic acid monomer or derivative by nonionic bonding (e.g., acrylamide, acrylonitrile, etc.)507/935, ENHANCED OIL RECOVERY524/829, Two or more N monomers525/157, Contacting with an amine, a material containing a N-C(=X)- or N-S(=O)- (X is chalcogen) reactant and an aldehyde or aldehyde derivative at least one of which is saturated, their condensate or solid polymer thereof525/328.4, Monomer containing two or more nitrogen atoms, or two or more nitrogen containing monomers525/329.4, Polymer derived from acrylamide or methacrylamide monomer526/306, Plural amide group containing604/368Collagen or gelling materialExaminersPrimary: Levin, Stanford M.International ClassesC08J 3/12 (20060101)C08F 2/32 (20060101) C09D 7/00 (20060101) AbstractDiscrete, spheroidal microgels of a water-swollen or water-swellable, cross-linked polymer such as cross-linked polyacrylamide are particularly useful as thickening agents for aqueous dispersions to be subjected to high shear and as agents for reducing the permeability of porous structures. |
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