Monday, December 3, 2012

Lenzing's Patent on Filmtruder use for Lyocell (1992)

This is the lyocell patent Lenzing claimed Courtaulds infringed in building the US Tencel plant.  They sued Courtaulds in 1993 and the case was summarily dismissed in the USA in 1995.   Courtaulds was awarded costs.  Lenzing later appealed.

The 1995 Judgement appears here.

United States Patent
Zikeli ,   et al.March 10, 1992
**Please see images for: ( Certificate of Correction ) **

Process and arrangement for preparing a solution of cellulose

There is disclosed a process for preparing solutions of cellulose in aqueous tertiary amine oxides from a suspension of cellulose in an aqueous solution of the tertiary amine oxide by supplying heat at a reduced pressure. The suspension is transported over a heating surface, spread in layers or coats, until a homogenous solution of the cellulose has formed, which has a viscosity of between 50 and 15,000 Pas.s. Feeding of the suspension and drawing-off of the homogenous solution are carried out continuously. The solutions are prepared in an indirectly heated evacuatable vessel provided with a stirring device. The vessel is designed as a cylindrical container including a centrically mounted stirring shaft having agitators joined thereto, the radial distance of the agitators from the internal wall of the container being 20 mm at the most. There are provided an intake for the cellulose suspension in the upper part of the container and an outlet for the homogenous collulose solution in its lower end.

Inventors:Zikeli; Stefan (Regau, AT), Wolschner; Bernd (Vocklabruck, AT), Eichinger; Dieter (Vocklabruck, AT), Jurkovic; Raimund (Lenzing, AT), Firgo; Heinrich (Vocklabruck, AT)
Assignee:Lenzing Aktiengesellschaft (Lenzing, AT
Family ID:25597486
Appl. No.:07/742,093
Filed:August 2, 1991

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