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:
May. 18, 1993
Filed:
Mar. 30, 1992
Tadashi Amano, Kanagawa, JP;
Minoru Shigemitsu, Ibaragi, JP;
Shin-Etsu Chemical Co., Ltd., , JP;
Abstract
A method for recovering unreacted monomers during preparation of a vinylic polymer comprises the steps of polymerizing a vinyl monomer in an aqueous medium in a polymerizer and then recovering unreacted monomers from the polymerization system, wherein a gas evacuation rate per unit charge weight of the monomer is controlled to the range of from 60 to 300 Nm.sup.3 /hr per ton of the monomer from the initiation of the monomer recovery till the pressure in the polymerizer reaches 2.5 kg/cm.sup.2 G and a superficial gas linear velocity is reduced to a level of not more than 0.008 m/sec when the pressure in the polymerizer reaches 2.5 kg/cm.sup.2 G. The method makes it possible to recover unreacted monomers quickly without causing carrying over of polymer particles formed and is effective to maintain high quality of vinylic polymers produced.