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:
Jun. 07, 1994
Filed:
Mar. 26, 1993
Yuanzhen Zhong, Wayne, NJ (US);
Hemant Parikh, Harriman, NY (US);
Paul D Taylor, West Milford, NJ (US);
Terry E Smith, Murray, KY (US);
ISP Investments Inc., Wilmington, DE (US);
Abstract
This invention relates to an improved process for producing a clear solution of vinylpyrrolidone (VP) and vinyl acetate (VA) monomers which comprises, in an anhydrous system, (a) reacting a C.sub.2 to C.sub.3 alcoholic solution containing said VA monomer and between about 60 and about 80 wt. % portion of total VP monomer in the presence of between about 0.05 and about 0.3 wt. % of a free radical initiator selected from the group consisting of tertamylperoxy pivalate and 2,2-azobis(2-methylbutyronitrile) or a mixture thereof for a period of from about 5 to about 10 hours, at a temperature between about 60.degree. and about 110.degree. C.; (b) gradually adding the remaining VP monomer in C.sub.2 to C.sub.3 alcohol solution at reaction temperature after the addition of the VA monomer is complete; (c) raising the temperature of the resulting reaction mixture to between about 110.degree. and about 150.degree. C.; (d) continuing the polymerization reaction at said higher temperature in the presence of from about 0.11 to about 0.6 wt. %, based on total monomers, of 2,5-dimethyl-2,5-bis(tert-butylperoxy) hexane and (e) cooling the resulting reaction mixture and recovering a homogeneous VP/VA copolymer C.sub.2 to C.sub.3 alcohol solution containing less than 100 ppm of residual vinylpyrrolidone monomer or vinyl acetate residual monomer.