Lenzing Aktiengesellschaft

Christian H Schlossnikl

Peter Gspaltl

Heinrich Firgo

Johann Kalleitner

Andreas Schweigart

Siegfried Ambrosch

Gerold Riedl

Raimund Jurkovic

Adalbert G Wimmer

Harmut R&uuml;f

Rudolf Kraft

Harmut Ruf

Reinhard Reinmuller

Franz Sasshofer

The invention relates to a process for the manufacture of cellulosic flat films and cellulosic membranes in the form of flat membranes whereby a solution of cellulose in an aqueous tertiary amine oxide is moulded in film form using an extrusion nozzle which has an oblong extrusion gap and is led into a precipitation bath via an air gap whereby the cellulosic flat film is formed in the precipitation bath, characterized in that the cellulosic flat film is stretched in the transverse direction after entering the precipitation bath.

Process for the production of cellulosic moulded bodies

The invention relates to a process for the production of a spunlaid fabric containing solvent-spun cellulosic fibers. The process is characterised in that a solution of cellulose in an aqueous tertiary amine oxide is extruded through a spinneret ( ) with orifices and the extruded filaments ( ) are stretched in an air gap and led into a precipitation bath ( ), the filaments in the precipitation bath ( ) are intercepted by a first conveyor device ( ) whereby a curtain of threads of filaments basically arranged parallel to each other and basically of constant thickness is formed on the first conveyor device ( ), the curtain of threads is transported by means of the first conveyor device ( ) out of the precipitation bath ( ) onto a second conveyor device inclined downwards ( ), and the curtain of threads is transported downwards on the second conveyor device ( ) onto a third conveyor device ( ), where the third conveyor device ( ) draws off the curtain of threads at a speed less than the speed of the curtain of threads transported downwards on the second conveyor device.

Process and device for the production of cellulosic moulded bodies

The invention relates to a process for the production of cellulosic flat films whereby a solution of cellulose is extruded in an aqueous tertiary amine oxide by means of an extrusion die which has an extrusion gap whereby the solution is moulded in the shape of a film and the extruded solution is led via an air gap to a precipitation bath. The process in accordance with the invention is characterized in that an extrusion die is used which has an extrusion gap b of 220 &mgr;m&lE;b&lE;280 &mgr;m. Moreover, the invention relates to flat films, obtainable by the amine oxide process with a thickness d of less than 20 &mgr;m, a width B of more than 30 cm, and a factor f of 65 or less, whereby f is defined as f&equals;d*(MD/TD), d is used in &mgr;m and whereby MD stands for the tenacity of the film in the longitudinal direction (N/mm ) and TD for the tenacity of the film in the transverse direction (N/mm ).

Process for the production of cellulosic flat films

The invention relates to a process for the production of cellulosic moulded bodies in the form of flat or tubular films and cellulosic membranes in the form of flat or tubular films whereby a solution of cellulose in an aqueous tertiary amine oxide is extruded using an extrusion nozzle whereby the solution can as the case may be also contain additives such as stabilizing and softening agents, pore formers and so on whereby a moulded solution results which has two surfaces and the extruded moulded solution is led over a gap into a precipitation bath and drawn off from the precipitation bath. The process in accordance with the invention is characterized in that the two surfaces of the moulded solution in the gap are each exposed to at least one gaseous medium whereby the medium to which the first surface is exposed differs from the medium to which the second surface is exposed in composition, properties and/or the state of motion.

The invention relates to a process for the manufacture of cellulosic flat films and of cellulosic membranes in the form of flat membranes whereby a solution of cellulose in an aqueous tertiary amine oxide is extruded by means of an extrusion nozzle, which has an extrusion gap, whereby the solution is shaped in the form of a film and the solution is led into a precipitation bath via an air gap and is characterized in that an extrusion nozzle is used which has an extrusion gap with a minimum length of 40 cm.

Method for producing cellulose shaped bodies

The invention relates to a process for producing a strengthened fiber assembly containing cellulosic fibers with the cellulose being present in the crystalline structure of cellulose II, by contacting the fiber assembly with an aqueous solution of N-methylmorpholine-N-oxide (NMMO) at elevated temperature and subsequently washing the fiber assembly, characterized in that contacting is effected in a manner that from the relation

Process for producing a strengthened fiber assembly

To produce a monoaxially stretched shaped article of polytetrafluoroethylene (PTFE), a pasty mass containing PTFE powder is continuously shaped to a shaped body, which is fed over a plurality of rollers or rolls, heated and stretched. The shaped body is heated to a temperature of between 327.degree. and 450.degree. C. prior to stretching strain, it is sintered simultaneously and is then stretched. This process allows for the production of a monoaxially stretched shaped article of PTFE which has strength values in the stretching direction of at least 500 N/mm.sup.2 and a delivery of between 1.80 and 2.30 g/cm.sup.3.

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Vocklabruck, Austria

Christian H Schlossnikl