Treetotextile Ab

Tobias Köhnke

Bengt Hagström

Carina Olsson

Artur Hedlund

Lars Stigsson

Marta Bialik

Jonas Engström

A process for forming a fiber tow, involves a wet spinning procedure comprising the steps of: dissolving cellulose pulp N in an alkaline aqueous solvent to form a cellulose spin dope composition, spinning the cellulose spin dope composition in a coagulation having a p H of more than 7.0, preferably a pH of at least 10, to produce a fiber tow, and passing the produced fiber tow through a sequence of consecutive stretching and washing steps in which the formed fiber tow is washed with a washing liquid by a counter-current flow washing procedure.

Process for wet spinning of cellulose fibers from an alkaline spin bath

The present disclosure describes a method for the production of a spinning dope composition, said method comprising a homogenization involving mixing a cellulosic pulp material in alkali solution, mixing implying supplying a power density to agitators used in the homogenization of at least 150 kW/m(KW supplied to agitators per mixed unit of liquid volume), and thereafter a dissolution involving mixing of the cellulosic pulp material in the alkali solution to obtain a spinning dope composition, wherein the power density supplied to agitators used in the dissolution step is maximum 75 kW/m(KW supplied to agitators per mixed unit of liquid volume); and wherein the cellulosic pulp material in alkali solution is kept at a temperature of less than 0° C. during the homogenization and during at least part of the dissolution. The present disclosure is also directed to a system intended for the production of a spinning dope composition.

Method and system for the production of a spinning dope composition

The present invention describes a method for the production of a spinning dope composition, said method comprising a homogenization involving vigorous mixing of a cellulosic pulp material in alkali solution, vigorous mixing implying supplying a power density to agitators used in the homogenization step of at least 150 kW/m(kW supplied to agitators per mixed unit of liquid volume), and thereafter a dissolution involving mixing of the cellulosic pulp material in the alkali solution to obtain a spinning dope composition, wherein the power density supplied to agitators used in the dissolution step is maximum 75 kW/m(kW supplied to agitators per mixed unit of liquid volume); and wherein the cellulosic pulp material in alkali solution is kept at a temperature of less than 0&#xb0; C. during the homogenization and during at least part of the dissolution. The present invention is also directed to a system intended for the production of a spinning dope composition.

System for the production of a spinning dope composition

The present invention describes a method for the production of a spinning dope composition, said method comprising a homogenization involving vigorous mixing of a cellulosic pulp material in alkali solution, vigorous mixing implying supplying a power density to agitators used in the homogenization step of at least 150 k W/m(k W supplied to agitators per mixed unit of liquid volume), and thereafter a dissolution involving mixing of the cellulosic pulp material in the alkali solution to obtain a spinning dope composition, wherein the power density supplied to agitators used in the dissolution step is maximum 75 k W/m(k W supplied to agitators per mixed unit of liquid volume); and wherein the cellulosic pulp material in alkali solution is kept at a temperature of less than 0&#xb0; C. during the homogenization and during at least part of the dissolution. The present invention is also directed to a system intended for the production of a spinning dope composition.

Method for the production of a spinning dope composition

The present invention relates to a process for forming cellulose fibers or film from dissolved cellulose. The process comprises the steps of: dissolving cellulose in an aqueous coagulation sodium salt solution to provide a cellulose spin dope; extruding the cellulose spin dope into a coagulation bath liquid comprising an aqueous coagulation sodium salt solution to provide cellulose fibers or film; withdrawing a portion of the coagulation bath comprising coagulation sodium salt and sodium hydroxide (NaOH); cooling the withdrawn portion of the coagulation bath to precipitate solid coagulation sodium salt to recover sodium hydroxide (NaOH) substantially free from the coagulation salt; and using at least a portion of the recovered sodium hydroxide (NaOH) in dissolving the cellulose to provide the cellulose spin dope.

Process for spinning dissolved cellulose

The present invention concerns a method for the recovery of solvent in a process for preparation of regenerated cellulosic fibers using sodium hydroxide as solvent for cellulose dissolving in the manufacturing of a cellulose spinning dope wherein sodium hydroxide present in the spinning dope is at least partially recovered and recycled as sodium hydroxide from a cellulose fiber regeneration or cellulose coagulation step and wherein said cellulose fiber regeneration or cellulose coagulation step consists of a bath into which cellulose spinning dope is injected. Recovered sodium hydroxide may be directly or indirectly recycled from a cellulose fiber regeneration or cellulose coagulation step to a cellulose dissolving step.

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Gothenburg, Sweden

Tobias Köhnke