The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 26, 1994
Filed:
Jan. 31, 1991
Jenn S Shih, Paramus, NJ (US);
Terry E Smith, Morristown, NJ (US);
ISP Investments Inc., Wilmington, DE (US);
Abstract
What is provided herein is a process for making homopolymers of polyvinylpyrrolidone polymer in the form of fine powders at a polymer solids level of at least about 17%, preferably 30% or more, and in a yield of at least about 95%, which comprises precharging a reactor with a predetermined amount of a solvent selected from a C.sub.3 -C.sub.20 alkane, preferably heptane, or a C.sub.3 -C.sub.20 cycloalkane, preferably cyclohexane, and a free radical polymerization initiator, and feeding vinylpyrrolidone monomer into the precharged reactor at a selected rate, preferably about 0.1 to 1.8 g vinylpyrrolidone/min/1000 g of solvent, and most preferably, about 1 g/min/1000 g of cyclohexane and 0.5 g/min/1000 g of heptane, which rates preclude build-up of monomer during the polymerization, and for a feed period which provides the desired level of polymer solids in the reaction product, preferably at least about 200 minutes. The polymer product may be isolated from the reaction mixture by filtration and drying, or by direct drying.