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:
Nov. 08, 1994
Filed:
Oct. 12, 1993
Atsuo Kawakami, Ube, JP;
Toshiro Shimada, Ube, JP;
Tatsuo Tsumiyama, Ube, JP;
Hisaya Yamaguchi, Ube, JP;
Ube Industries, Ltd., Ube, JP;
Abstract
A continuous polymerization method for laurolactam which has three stages. A prepolymerization process include steps of preliminarily heating laurolactam with 1 to 10% weight of water added, thereafter continuously feeding and passing the laurolactam from the upper part of the lower part of the longitudinal-type polymerization reaction zone, arranging a temperature decreasing gradient of 10.degree. C. or more than the upper part to the lower part directions at a polymerization temperature of 250.degree. and 300.degree. C. in the polymerization zone, and polymerizing the laurolactam under vapor pressure up to a conversion rate of 99.5% or more. A intermediate process has a step of releasing pressure from the prepolymerization product from the prepolymerization process for conversion into an intermediate product at atmospheric pressure. A post polymerization process includes the steps of continuously feeding the intermediate product at atmospheric pressure from the intermediate process in the direction from one end of the lower end to the other lower end of the traverse-type polymerization zone, polymerizing the intermediate product with agitation and air discharge in the presence of inert gas under reduced pressure or atmospheric pressure to a final relative viscosity of .eta..sub..tau. of 1.9 to 3.3.