Process of making cellulose fibres

Details Process of making cellulose fibres Process of making cellulose fibres

1995-01-04

1996-08-06

Tentoni, Leo B.

Plastic and nonmetallic article shaping or treating: processes

Forming continuous or indefinite length work

Shaping by extrusion

26421111, 26421116, D01F 202

Patent

active

055431011

DESCRIPTION:

BRIEF SUMMARY
FIELD OF THE INVENTION

The present invention is concerned with cellulose fibres and a process for the production of cellulose fibres by extruding a solution of cellulose in a tertiary amine-oxide through spinning holes of a spinneret and conducting the extruded filaments across an air gap into a precipitation bath while drawing them.


BACKGROUND OF THE INVENTION

As an alternative to the viscose process, in recent years there has been described a number of processes in which cellulose, without forming a derivative, is dissolved in an organic solvent, a combination of an organic solvent and an inorganic salt, or in aqueous saline solutions. Cellulose fibres made from such solutions have received by BISFA (The International Bureau for the Standardisation of man made Fibres) the generic name Lyocell. As Lyocell, BISFA defines a cellulose fibre obtained by a spinning process from an organic solvent. By "organic solvent", BISFA understands a mixture of an organic chemical and water. "Solvent-spinning" is considered to mean dissolving and spinning without the forming of a derivative.
So far, however, only one process for the production of a cellulose fibre of the Lyocell type has achieved industrial-scale realization. In this process, N-methylmorpholine-N-oxide (NMMO) is used as a solvent. Such a process is described for instance in U.S. Pat. No. 4,246,221 and provides fibres which present a high tensile strength, a high wet-modulus and a high loop strength.
However, the usefulness of plane fibre assemblies, for example fabrics, made from the above fibres, is significantly restricted by the pronounced tendency of the fibres to fibrillate when wet. Fibrillation means the breaking up of the fibre in the longitudinal direction at mechanical stress in a wet condition, so that the fibre gets hairy, or furry. A fabric made from these fibres and dyed significantly loses color intensity as it is washed several times. Additionally, light stripes are formed at the abrasion and crease edges. The reason may be that the fibres consist of fibrils which are arranged in the longitudinal direction of the fibre axis and that there is only little crosslinking between these.
WO 92/14871 describes a process for the production of a fibre having a reduced tendency to fibrillation. The reduced tendency to fibrillation is attained by providing all the baths with which the fibre is contacted before the first drying with a maximum pH value of 8.5.
WO 92/07124 also describes a process for the production of a fibre having a reduced tendency to fibrillation, according to which the not dried fibre is treated with a cationic polymer. As such, a polymer with imidazole and azetidine groups is mentioned. Additionally, there may be carried out a treatment with an emulsifiable polymer, such as polyethylene or polyvinylacetate, or a crosslinking with glyoxal.


SUMMARY OF THE INVENTION

In a lecture given by S. Mortimer at the CELLUCON conference in 1993 in Lund, Sweden, it was mentioned that the tendency to fibrillation rises as drawing is increased.
It has been shown that the known cellulose fibres of the Lyocell type still leave something to be desired in terms of tendency to fibrillation, and thus it is the object of the present invention to provide a cellulose fibre of the Lyocell type having a further reduced tendency to fibrillation.
This objective is attained in a process described at the beginning by carrying out the process in a way that the mathematical expression -7.18.times.T-0.094.times.L-2.50.times.F+0.045F2 hole in g/min, T is the titer of the individual filament in dtex, L is the length of the air gap in mm and F is the humidity of the air in the air gap in g of water/kg of air, does not exceed the number 10, with the provision that the length of the air gap is provided greater than 30 mm.
The invention is based on the finding that by adjusting the spinning parameters, the structure of the cellulose fibre can be influenced in such a positive way that a fibre having a reduced tendency to fibrillation is formed.


DETAILED DESCRIPTI

REFERENCES:
patent: 4246221 (1981-01-01), McCorsley, III
patent: 4416698 (1983-11-01), McCorsley, III

Affiliated with

Also associated with

Rating

Process of making cellulose fibres does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Process of making cellulose fibres, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process of making cellulose fibres will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2189205