Thursday, August 9, 2012

First Lenzing Lyocell patent (1991)

This appears about 8 years after the first Courtaulds NMMO patent and furthermore after the design of the Mobile plant had been finalised.

United States Patent
Zikeli ,   et al.March 10, 1992

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
Appl. No.:07/742,093
Filed:August 2, 1991

see also:
A 2036/88Austria1988-08-16

Click here for full patent

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