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:
Mar. 31, 1992
Filed:
Apr. 12, 1990
Norbert Hasenbein, Dirmstein, DE;
Wolfgang Ball, Mannheim, DE;
Juergen Schmidt-Theummes, Neuhofen, DE;
Gernot Koehler, Worms, DE;
BASF Aktiengesellschaft, Ludwigshafen, DE;
Abstract
Polyethylene and copolymers of predominant amounts of ethylene and minor amounts of comonomers which are polymerizable with ethylene are obtainable by free radical polymerization of the monomers under from 1,500 to 5,000 bar and at from 40.degree. to 250.degree. C. by means of an initiator with virtually complete exclusion of oxygen in not less than n=3 polymerization stages, by a method in which, in the first stage, the total amount of the predominant part of the monomers are subjected to polymerization using some of the initiator required, until said polymerization comes virtually to a stop, thereafter a further part of the initiator and, if required, of the monomers are added to the mixture, which has been cooled by 20.degree.-60.degree. C., and this process is repeated in the subsequent stages until the n th stage, with the proviso that the initiators used in the (n-1) th stage have a half-life temperature of from 80.degree. to 160.degree. C.