Method of crosslinking PVP
Patent 5219950 Issued on June 15, 1993. Estimated Expiration Date: 
September 16, 2012. 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 16, 2012. 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 3178397 3563968 1-Thiadiazolyl-4-methoxymethyl-5-hydroxyimidazolidinones Small-globular crosslinked monoallylamine polymer and process for producing the same Biologically useful polymer preparations Strongly swellable, moderately crosslinked polyvinylpyrrolidone Patent #: 5073614 InventorsAssigneeApplicationNo. 945565 filed on 09/16/1992US Classes:525/359.3, Organic halogen-containing compound contains oxygen525/328.2, Polymer derived from monomer containing nitrogen other than: unsubstituted ammonium, acrylonitrile, acrylamide, methylolacrylamide and the corresponding methacryl materials525/328.7, Polymer derived from aldehyde monomer525/328.8, Polymer derived from alcohol monomer525/355, Chemical treating agent contains hydrogen halide, elemental halogen, organic halogen-containing compound, or compound containing only halogen atoms525/385, Oxygen compound contains an ether group526/307.5, Oxygen atom is part of ether or hydroxyl group526/312Contains oxygen atom bonded to a carbon atomExaminersPrimary: Schofer, Joseph L.Assistant: Zitomer, Fred Attorney, Agent or FirmInternational ClassesC08C 019/32C08C 019/38 C08F 026/08 C08F 026/10 AbstractThe method of crosslinking polyvinylpyrrolidone (PVP) which comprises: copolymerizing vinyl pyrrolidone (VP) and an aminoalkene, a hydroxyalkene, or an aminoalkyl acrylamide or methacrylamide, to provide a crosslinkable, functional PVP copolymer as a starting material; then (a) condensing predetermined amounts of the starting material and a haloacetal under basic conditions to form a stable, crosslinkable PVP copolymer intermediate containing an acetal group as a functional appendant on the PVP polymer backbone; (b) acidifying the basic solution to hydrolyze the acetal group to an aldehyde group, and (c) crosslinking the aldehyde-functional PVP copolymer with the amine group of the amine-functional PVP copolymer, present on the polymer as free amine after step (a), or as added amine-functional copolymer to the reaction mixture, under basic conditions. | |
