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. 29, 1980
Filed:
Jul. 17, 1978
Jozef L van der Loos, Sittard, NL;
Wilhelmus G Duijzings, Born, NL;
Stamicarbon, B.V., Geleen, NL;
Abstract
An improved process for the preparation of copolymers by the polymerization of from about 25 to 85 parts by weight of a styrene and/or .alpha.-methylstyrene monomer together with about 15-75 parts by weight of acrylonitrile and/or methacrylonitrile monomer in an aqueous dispersion in the presence of a compound yielding free radicals is disclosed whereby the quantity of monomer remaining in the copolymer after polymerization is substantially reduced. A compound yielding water-soluble free radicals is added to the aqueous reaction medium, containing copolymer as well as non-converted monomer, in a quantity of between about 0.05 and 2.5 parts per 100 parts by weight of monomer and copolymer present in the reaction medium, at a point of time at which (a) the rate of conversion of monomer to copolymer is less than 15% per hour, (b) the degree of conversion of monomer to copolymer is greater than 75%, and (c) at least 0.1 weight percent of non-converted acrylonitrile and/or methacrylonitrile relative to the total weight of the reaction medium, remains in the reaction medium, and whereafter no additional monomer is added.