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:
Jul. 22, 2014
Filed:
Jun. 09, 2011
Enrico Balestra, Ferrara, IT;
Tiziana Caputo, Ferrara, IT;
Antonio Mazzucco, Ferrara, IT;
Riccardo Rinaldi, Mantova, IT;
Silvia Soffritti, Ferrara, IT;
Enrico Balestra, Ferrara, IT;
Tiziana Caputo, Ferrara, IT;
Antonio Mazzucco, Ferrara, IT;
Riccardo Rinaldi, Mantova, IT;
Silvia Soffritti, Ferrara, IT;
Basell Poliolefine Italia S.r.l., Milan, IT;
Abstract
A process for the gas-phase copolymerization of: (a) propylene, (b) at least one C-Cα-olefin, and (c) optionally ethylene, the process being carried out in a reactor having two interconnected polymerization zones, wherein the growing polymer particles flow through the first of said polymerization zones (riser) under fast fluidization conditions, leave said riser and enter the second of said polymerization zones (downcomer) through which they flow downward in a densified form, leave said downcomer and are reintroduced into said riser, thus establishing a circulation of polymer between the riser and the downcomer, the gas mixture present in the riser being at least partially prevented from entering the downcomer by introducing into the upper part of said downcomer a liquid barrier having a composition different from the gaseous mixture present in the riser and comprising at least one C-Cα-olefin in a total amount of from 0.1% to 35% by mol.