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. 05, 2009
Filed:
Oct. 20, 2005
Bernardus Maria Koenders, Westervoot, NL;
Bernardus Maria Koenders, Westervoot, NL;
Teijin Aramid B.V., Arnhem, NL;
Abstract
Described is a method for dissolving PPTA or copolymers thereof in sulfuric acid using a twin screw extruder having transporting, mixing, and kneading elements with an entering zone, an intermediate zone, a mixing zone, a negative transport zone, a degassing zone, and a pressure build-up zone. The method includes transporting PPTA or copolymer thereof into the entering zone at a transport capacity low enough as to prevent sulfuric acid entering the entering zone; introducing sulfuric acid in the intermediate zone; essentially fully filling the mixing zone to allow sufficient time to mix and dissolve PPTA or copolymer thereof in the sulfuric acid to obtain a PPTA or copolymer-sulfuric acid solution; creating after the mixing zone a negative transport zone to obtain a product lock between the mixing zone and the degassing zone; creating a thin film of the PPTA or copolymer-sulfuric acid solution in the degassing zone to degas the solution; and entering the solution into the output pressure build-up zone to partially fill this zone and to leave the twin screw extruder.