Styrene/acrylic-type polymers for use as surface sizing agents
Patent 5139614 Issued on August 18, 1992. Estimated Expiration Date: 
June 3, 2011. 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.
June 3, 2011. 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 2851448 Material used to bear writing or printing Patent #: 4481244 InventorsAssigneeApplicationNo. 709254 filed on 06/03/1991US Classes:162/135, With coating after drying162/168.1, Polymerized unsaturated compound427/391Paper baseExaminersPrimary: Schofer, Joseph L.Assistant: Nagumo, M. Attorney, Agent or FirmForeign Patent References
International ClassD21H 019/20AbstractA process is disclosed for the preparation of styrene/acrylic type polymers which are useful in the sizing of paper. The process comprises polymerizing the monomers in an alcohol/water mixture at reflux temperature in the presence of a free-radical generating catalyst. The catalyst is added portion-wise over the course of the reaction and the resultant polymer is neutralized while substantially simultaneously separating the alcohol/water mixture and adding water to recover a product of less than 25% polymer solids. | |
