Lenzing Lyocell Patent (1995)

In looking through the Courtaulds and Lenzing patents on lyocell, this is the first I've seen which covers a process for making fibres as opposed to different parts of a process.  It is also the first to mention the Buss Filmtruder as the thin-film evaporator, this being the evaporator installed at Mobile Tencel in 1992 and operating commercially when this was filed.

United States Patent	5,603,883
Zikeli	February 18, 1997

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Process of and apparatus for making celluose products

Abstract A plant for the production of cellulose films and fibers includes at least one pulping device for producing a first suspension of pulp in an aqueous amine-oxide solution and a first thin-film treatment apparatus for receiving the first pulp suspension and producing a concentrated pulp suspension. The plant also includes a second thin-film treatment apparatus wherein the concentrated pulp suspension is transformed into a mouldable solution of cellulose and a spinning device connected to the second thin-film treatment apparatus, wherein the mouldable cellulose solution is processed into cellulose films and fibers. A process for the production of cellulose films and fibers according to an amine-oxide process includes the steps of suspending pulp in an aqueous amine-oxide solution to produce a first suspension, concentrating the first suspension, producing a mouldable cellulose solution by heating, and processing the solution to form cellulose films and fibers.

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Inventors:	Zikeli; Stefan (Regau, AT)
Assignee:	Lenzing Aktiengesellschaft (AT)
Appl. No.:	08/465,321
Filed:	June 5, 1995 100 kg of humid pulp of the "Lenzing BKZ EM 9 feucht" type containing 50% of water was suspended for about 5 minutes in a pulper of the company Cellwood Grubbens AB (vertical pulper) in 600 kg of a commercially available solution of N-methylmorpholine-N- oxide having an NMMO content of approximately 58% by mass. A homogeneous pulp suspension having a dry substance density of 8, 33% by mass of pulp was obtained.  This suspension (58.degree. C.) was fed into a FILMTRUDER.RTM. of the Buss HS/HSG 0200 type at a rate of 600 kg/h and therein concentrated to a dry substance density of 12, 38% by mass of pulp. The heating surface of the FILMTRUDER.RTM. was heated by means of saturated vapor at 160.degree. C. The circumferential rate of the rotor was 4 m/s. Approximately 404 kg of concentrated suspension per hour having a temperature of 85.degree. C. could be withdrawn from the FILMTRUDER.RTM..  The concentrated suspension was fed into the FILMTRUDER.RTM. of the Buss HS 0200 type at a temperature of 80.degree. C. at a rate of about 404 kg/h, therein further concentrated and finally transformed into a mouldable solution having a cellulose concentration of 15, 0%. The heating surface of the FILMTRUDER.RTM. was heated by means of saturated vapor at 142.degree. C. The circumferential rate of the rotor was 4 m/s. Approximately 333 kg of mouldable cellulose solution per hour having a temperature of 105.degree. C. could be withdrawn from the FILMTRUDER.RTM..