Plastic and nonmetallic article shaping or treating: processes – Forming continuous or indefinite length work – Shaping by extrusion
Patent
1997-09-08
1999-02-09
Tentoni, Leo B.
Plastic and nonmetallic article shaping or treating: processes
Forming continuous or indefinite length work
Shaping by extrusion
264187, 2642108, 26421112, 26421114, D01F 202
Patent
active
058689850
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a process for manufacturing cellulose fibers by extrusion of a spinning solution, containing dissolved cellulose, into a gaseous medium through a predetermined gas zone, with subsequent immersion in and guidance through a coagulation bath over a predetermined coagulation zone, drawing the cellulose fibers obtained and winding them up.
Such a process is for example known from DE-A-4409609. The spinning solution is immersed in a stationary coagulation bath after passage through the gas zone, and the coagulation bath is then accelerated along with the spinning solution. The acceleration of the coagulation bath takes place via a spinning funnel which is conically tapered at the bottom. Such a spinning funnel has the disadvantage that the spinning initiation poses considerable problems. The maximum winding velocity obtainable is 150 m/min according to the examples, so that this known process is not very economical.
An additional process of this type is known from JP-A-61-19805, where again the spinning solution is extruded into a spinning funnel, whereby due to the encapsulation of the gas zone, the gas atmosphere into which the spinning solution is extruded is strongly enriched with the coagulation liquid, causing hereby a pre-coagulation in the gas zone which is not always desirable. In this known process the coagulation liquid is to be guided as a stream over the wall of the spinning funnel, resulting in turbulence right at the point of contact between the spinning solution and the coagulation liquid. This turbulence causes frequent spinning breaks so that this process only leads to a stable spinning process when using spinning solutions with very little cellulose. The examples state winding velocities of up to 1500 m/min. However, this is obtained by costly arrangements of several acceleration funnels, which in the first place renders the spinning initiation difficult and secondly makes a stable spinning process considerably more complicated.
BRIEF DESCRIPTION OF THE DRAWING
The FIG. depicts an apparatus for manufacturing fibers according to the present invention.
The objective of the present invention is to make a further spinning process for the production of cellulose fibers available, which works more economically. In particular, it should at least reduce the above mentioned disadvantages. It should also provide a process for the production of cellulose fibers which is also stable even at winding velocities exceeding 1000 m/min, and with sensitive cellulose spinning solutions, such as is the case with solutions of cellulose in a water-containing N-oxide of a tertiary amine, particularly N-methylmorpholine-N-oxide (NMMO).
This objective is met by the process of the type initially described in that, after the gas zone, the extruded spinning solution is introduced into a coagulation bath accelerated to a predetermined velocity and flowing laminarly at least approximately in the direction of the extruded spinning solution, whereby the coagulation liquid is fed laterally into the path of the spinning solution and the flow direction of the spinning solution and the coagulation liquid is kept at least approximately parallel throughout the entire coagulation zone, and in that the cellulose fibers obtained are deflected laterally when leaving the coagulation zone and are subsequently wound up.
The lateral laminar feeding of the coagulation liquid can be easily obtained in that one side of a reservoir for the coagulation liquid is formed as a spillway, whereby the spillway is shaped in such a way that the coagulation liquid on the one hand flows along the contour and on the other hand is redirected from the horizontal into the flow direction of the spinning solution. This contour can in a simple case be shaped like a quarter circle or a parabola, but attention should be paid to the fact that a steady curve is formed from the outlet to the transition into the flow direction of the spinning solution to guarantee that turbulence is for the most part avoided, s
REFERENCES:
patent: 5417909 (1995-05-01), Michels et al.
Abstract of Japan 59-228,012 (Published Dec. 21, 1984).
Akzo Nobel nv
Tentoni Leo B.
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