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:
Dec. 02, 2003
Filed:
Jan. 08, 2002
Mitsubishi Gas Chemical Company, Inc., Tokyo, JP;
Abstract
In the process for producing polyamide of the present invention, a diamine and a dicarboxylic acid are melt-polycondensed in a batch-wise fist polymerizer in the absence of a solvent to produce a middle-stage polyamide. The diamine has a boiling point higher than a melting point of the middle-stage polyamide being produced under inner pressures of the first polymerizer. The middle-stage polyamide is fed into a continuous second polymerizer while controlling the change of relative viscosity within ±0.2, and further polycondensed there to produce the objective polyamide. With such a process, the change of polymerization degree of the middle-stage polyamide during the switching of the polymerization step from a batch-wise manner to a continuous manner is avoided, thereby preventing the variation in quality of the final product.