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. 14, 1998
Filed:
Jun. 28, 1996
Takashi Kobayashi, Ibaraki-ken, JP;
Tadashi Amano, Ibaraki-ken, JP;
Yoshitaka Okuno, Ibaraki-ken, JP;
Hideshi Kurihara, Ibaraki-ken, JP;
Tadaaki Kurokawa, Ibaraki-ken, JP;
Shin-Etsu Chemical Co., Ltd., Tokyo, JP;
Abstract
A vinyl chloride polymer is prepared through suspension polymerization of a vinyl chloride monomer in the presence of a polymerization initiator in a reactor. The reactor is charged with up to 4/5 of the overall monomer charge to initiate polymerization. Polymerization is carried out under a certain saturated vapor pressure of P1 kgf/cm.sup.2 at a preset polymerization temperature. When the internal pressure of the reactor declines to P2 kgf/cm.sup.2, the remainder of the overall monomer charge is continuously fed to the reactor so as to maintain the internal pressure within the range of (P1-.DELTA.P) wherein .DELTA.P=P1-P2 ranges from 0.1 to 2.0 kgf/cm.sup.2. A vinyl chloride polymer having a high degree of polymerization is efficiently produced while alleviating the load of heat removal.