Zimmer Aktiengesellschaft

Lenzing Aktiengesellschaft

Alceru Schwarza Gmbh

Uwe Kind

Ralf-Uwe Bauer

Leo Kagalowski

Marco Blech

A method of regulating the composition of the cellulose-containing extrusion solution in the production of cellulosic molded articles, whereby (a) cellulose is mixed with an aqueous amine oxide solution; (b) the mixture is converted to the extrusion solution by evaporation of water in vacuo at an elevated temperature and by input of shearing energy; (c) the extrusion solution is extruded, forming the cellulosic molded article, and is coagulated in a coagulation bath, and (d) the resulting molded article is washed to remove the residual amine oxide, characterized in that in step (a) the cellulose/amine oxide ratio is kept at a predetermined level by preregulation, and the water content of the extrusion solution is kept at a predetermined level by a main regulation after leaving step (b). This method allows accurate regulation of the composition of the solution.

Method and device for controlling the composition of the cellulose containing extrusion solution in the lyocell process

Process for manufacture of cellulose mouldings, such as fibres, filaments, or films, from TCF-bleached or ECF-bleached cellulose, in which the bleached cellulose is dissolved in an aqueous tertiary aminoxide to form a mouldable cellulose, the cellulose solution deforms, and the moulding comes into being by coagulation of the deformed solution, characterized in that, to reduce the cellulose decomposition in the process, TCF-bleached cellulose is used comprising carboxyl group content in the range from 1 to 35 &#x3bc;mol/g or an ECF-bleached cellulose with carboxyl group content in the range from 1 to 50 &#x3bc;mol/g. Cellulose mouldings having a reduced cellulose decomposition may be formed by said process.

Method for producing cellulose shaped-bodies

The invention relates to a method for continually producing an extrusion solution for producing cellulosed shaped bodies, such as fibres and films, according to the lyocell method. According to the inventive method, (a) a cellulose suspension is produced from cellulose and an aqueous phase in a mass ratio ranging from 1:3 to 1:40, whereby shearing is maintained for between 5 to 200 minutes. (b) The cellulose suspension is dewatered to form a material having a cellulose content ranging from 20 to 80 mass % and the aqueous phase produced thereby is at least partially returned to step (a). (c) The humid cellulose material being homogenised is transported through a first shearing zone in the absence of N-methylmorpholine-N-oxide. (d) The cellulose material is transported through a second shearing zone after sufficient aqueous N-Methyl-morpholine-N-oxide has been added to the homogenised cellulose material so that, after mixing, a suspension having a N-Methylmorpholine-N-oxide content ranging from 70 to 80 mass % in the liquid phase is obtained. The cellulose material or the suspension completely fills in the available cross-section of transport in the shearing zones and (e) the produced cellulose suspension being sheared is converted into the extrusion solution in aqueous N-Methylmorpholine-N-oxide, whereby water evaporates.

Method and device for continually producing an extrusion solution

A procedure to continuously produce a suspension of cellulose in aqueous N-methylmorpholine-N-oxide is characterized in that: (a) The cellulose is conveyed through a first shearing zone in the absence of N-methylmorpholine-N-oxide and is homogenized, and (b) the homogenized cellulose is conveyed through a second shearing zone after adding enough aqueous N-methylmorpholine-N-oxide for a suspension to result in a N-methylmorpholine-N-oxide content in the liquid phase of 70-80 weight percent after mixing, whereby the cellulose or suspension almost completely fills the available content cross-section in the shearing zones.

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Rudolstadt, Germany

Uwe Kind