US Patent 7521524 Polymerization method and polymerization apparatus

Patent 7521524 was granted and assigned to Hitachi on April, 2009 by the United States Patent and Trademark Office.

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Is a

Patent

Patent attributes

Current Assignee

Hitachi

Patent Jurisdiction

United States Patent and Trademark Office

Patent Number

7521524

Date of Patent

April 21, 2009

Patent Application Number

11071326

Date Filed

March 4, 2005

Patent Primary Examiner

‌

Duc Truong

Patent abstract

A polymerization method comprises, prior to polymerization of a monomer of the cyclic dimer of alpha-hydroxycarboxylic acid, a first mixture of a polymerization catalyst by bypassing a part of the monomer of the cyclic dimer is prepared. Then, the first mixture is mixed with a dominant amount of the monomer introduced into a polymerization reactor. The monomer of the cyclic dimer in the polymerization reactor is conducted in the presence of a polymerization initiator.