EP0832995A2 - Device for implementing a dry/wet spinning process - Google Patents

Abstract

A container (1') holds fluid for a spinning bath in which a dry-wet spinning process takes place. Here there is in the container a direction changing agent (2') for the extruded filaments and their gathering together. This agent can be swung in the vertical plane. Also claimed are (A) the process which entails the extrusion of a polymer dope through a spinneret (7') with high perforation density into a gaseous medium to form an array of filaments which are then drawn into the bath fluid, gathered in a bundle and led via the direction changing agent, where the distance of the direction changing agent from the spinneret is such that the angle between the outermost filaments of the array and the vertical through the spinneret does not exceed 20 degrees ; and (B) the application of the container to the process where a plastic soln. of cellulose in aq. tertiary amino oxide is spun.

Description

The invention relates to a device for carrying out a Dry / wet spinning process.

The technique of dry / wet spinning exists entirely generally in that dope is formed by a molding tool, e.g. a spinneret, in a non-falling for the spinning mass Medium, e.g. Air or an inert gas, is extruded, wherein in the case of using a spinneret filaments are formed which are stretched in this medium and then in a spinning bath liquid (precipitation bath) are carried out in which the filaments coagulate.

WO 93/19230 by the applicant is a method and Device for producing cellulosic fibers known according to which a solution of cellulose in a tertiary Amine oxide molded in the warm state and the molded solution introduced into the precipitation bath by a gaseous medium (air) to precipitate the cellulose contained, the warm, shaped solution cooled before introduction into the precipitation bath becomes. Cooling is done immediately after molding and preferably consists in a horizontal blowing of the cellulosic molded body with air. The invention Process allows spinning the cellulose solution with high Thread density without causing the filaments to stick together comes out of the spinneret.

DD-A-218 121 also relates to a Dry / wet spinning process for the production of cellulosic Fibers from cellulose solutions in tertiary amine oxides. Also According to this method, the cellulose solution is divided into one Air gap, that is the distance between the spinneret and the Surface of the spinning bath liquid, spun, stretched and led into an aqueous precipitation bath. In DD-A - 218 121 mentions that the air gap has no adverse consequences for the Spinning security can be shortened if the cellulose solution a polyalkylene ether is added before spinning. A Small air gap is advantageous because of the risk of Gluing of the freshly extruded filaments is reduced.

EP-A-0 574 870 describes a dry / wet spinning process for processing solutions of cellulose in tertiary Amine oxides are described and taken advantage of a small Air gap noted. With this spinning process it is after Information in the description section of this patent application possible, with a small air gap and with a high number of To spin spinning holes per unit area. Despite this In spinning operation, there should be no sticking of the Filaments are coming. It is recommended that you contact the spun filaments with the spinning bath liquid in one Spinning funnel. Co-current with the filaments spinning bath liquid is passed through this spinning funnel. The axis of the spinning funnel is essentially vertical to the level of the spinneret, and the flow of the Spin bath liquid is directed from top to bottom, whereby the flow in general through the free fall of the Spin bath liquid is formed.

The delay or the stretching of the freshly extruded Filaments is achieved according to EP-A - 0 574 870 so that the Filaments from the one flowing through the spinning funnel Spin bath liquid essentially on their Take-off speed can be accelerated.

This known spinning device has the disadvantage that the funnel tube of the spinning funnel due to its relative narrow diameter of the filament bundle to be carried out an upper limit with regard to its total cross section sets that for a large-scale implementation of the Procedure is set unsatisfactorily deep. So it is after Experience of the applicant of the present application at a diameter of 6 mm, as described in EP-A - 0 574 870 a filament bundle is only given as an example consisting of a maximum of 100 filaments through the funnel lead as spin bath liquid through the funnel must be transported. This in turn means that at Using such a spinning funnel only one spinneret can be used with a maximum of 100 spinning holes.

On the other hand, it becomes a wide spinneret with tens of thousands Spinning holes used, such as in the Austrian patent application A 2724/89 by the applicant is described, the funnel tube must be correspondingly larger be, which in turn makes a lot more spin bath liquid drains and must be circulated. This high throughput Spin bath liquid leads to turbulent flows in the Spin bath, which interferes with the dry / wet spinning process.

In GB-A-1,017,855 a device for Dry / wet spinning of synthetic polymers is described. Again, the use of a spinning funnel is recommended through which spin bath liquid co-current with the extruded fibers is allowed to flow through. The spinneret is about 0.5 cm above the surface of the spin bath.

(a) bei kleiner Verzugsstrecke (Luftspalt) zu verspinnen, und

(b) Spinndüsen zu verwenden, die eine hohe Lochdichte aufweisen und einen hohen Spinnmassedurchsatz gestatten.

The object of the invention is to provide a container for holding spinning bath liquid, which makes it possible to carry out a dry / wet spinning process with high spinning safety without using a spinning funnel, and at the same time:

(a) spinning with a small warpage (air gap), and

(b) To use spinnerets that have a high hole density and allow a high spinning mass throughput.

Furthermore, in the device according to the invention in the spinning bath a turbulent flow should be avoided if possible. Furthermore should allow the device according to the invention, spinnerets to use different sizes without the Device must be converted, i.e. that the device of adapted each spinneret used in a simple manner can be.

The container according to the invention for holding spin bath liquid to carry out a dry / wet spinning process, which process involves using a spinning mass through a spinneret high spinning hole density extruded in a gaseous medium , forming a cluster of filaments formed by the gaseous medium with delay in the spin bath liquid are introduced, is characterized in that in the Container a deflector for bundling and deflecting the Filaments is provided, which is in the vertical plane is pivotable.

The filament family is thus in the container according to the invention not from a spinning funnel, as in EP-A - 0 574 870 described, but bundled by a deflector.

It has been shown that for spinning safety Dry / wet spinning processes are very important that the draft angle in the air gap is as small as possible and preferably does not exceed 20 °. As a draft angle denotes the angle that the outermost filament or Edge filament of a filament group leaving the spinneret with the perpendicular to the spinneret level. With the The device of the invention can now be independent of the The size of the spinneret used is always the same Set the draft angle. This can reduce the risk of Bonding of the filaments in the space between the spinneret and the Surface of the spinning bath minimized and the spinning security increase.

A preferred embodiment of the invention Container is that the deflecting one in has essentially cylindrical body of two in essential annular flanks is limited, the of the flanks formed preferably one with each other Include angles between 7 ° and 30 °. This embodiment is especially beneficial for spinning start, like below is performed.

(a) eine Leitung zum Einbringen von Spinnbadflüssigkeit in den Behälter, welche Leitung am unteren Ende des Behälters vorgesehen ist,

(b) eine Ableitung für Spinnbadflüssigkeit, die am oberen Ende des Behälters vorgesehen ist.

A further preferred embodiment of the container according to the invention has the following further features:

(a) a line for introducing spin bath liquid into the container, which line is provided at the lower end of the container,

(b) an outlet for spin bath liquid which is provided at the upper end of the container.

It has been shown that the container according to the invention particularly good for dry / wet spinning formable solutions from Cellulose in an aqueous tertiary amine oxide is suitable.

The invention further relates to a method for Dry / wet spinning by extrusion of a dope a spinneret with high spinning hole density in a gaseous Medium, forming a cluster of filaments, which delayed by the gaseous medium in a Spinning bath liquid introduced, bundled and over Guide element are guided, which is characterized in that the deflector at such a distance from Spinneret is that the angle between the outermost Filaments of the filament array and the perpendicular to the Spinneret does not exceed 20 °.

In the process according to the invention, the spinning bath liquid not run in direct current with the filaments and the delay thus not with the kinetic energy of the spinning bath liquid as detailed below.

In the process of the invention, preference is given to spinning mass a moldable solution of cellulose in an aqueous tertiary Amine oxide used.

With the drawing, a preferred embodiment of the The device according to the invention explained in more detail, the Figure 1 is a general representation of the FIG. 2 shows a dry / wet spinning process perspective view of an embodiment of the 3 schematically shows the container according to the invention and FIG the deflector shown in Figure 2 shows.

In Figure 1, 1 is a container for receiving Spinning bath liquid called, the surface of the Spin bath liquid is indicated with 1a. During the spinning process spinning mass is extruded through the spinneret 7 and the extruded filaments over the air gap LS in the Drawn off spin bath liquid in which they coagulate. At the Deflector 2, the coagulated filaments are deflected and deducted diagonally upwards. The distance is the air gap LS the underside of the spinneret 7 from the surface 1a of the Spin bath liquid defined. The one defined above Distortion angle is denoted by α.

In Figure 2, the reference numeral 1 'is a trough-shaped Container for holding spinning bath liquid called. The Spin bath liquid is via line 3 at the lower end of the container 1 'fed and flows upwards. Is the Container filled, then spin bath liquid passes over the Overflow edge 5 in the drain collecting cup 6, thereby a consistently high liquid level in the container 1 ' is maintained.

The spinning bath liquid overflowed into the drain collection cup 6 is drained via the lead 4 and via a external pump system (not shown) again via line 3 fed to the container 1 'according to the invention. Conveniently the derivation 4 is provided with a sieve to possibly filter any filament residues.

To keep turbulent flow as little as possible in the spinning bath generate, a baffle plate 10 is provided in the container 1 ', attached parallel to the wall of the container (not shown) is.

Reference number 7 'denotes a spinneret, wherein the emerging filaments are indicated with dashed lines are.

A preferred spinneret is in the International Patent application WO 93/19230 described by the applicant. Reference numeral 2 'denotes a deflecting element, via which the Filament coulter bundled and pulled off diagonally upwards (not will be shown. The deflection element 2 'is connected to an arm 8 a rotatable axis 9 attached. The axis 9 is on the side in the wall of the container 1 'rotatably and naturally sealed so that no spin bath liquid can escape. By turning the axis 9, the deflection element 2 'in the container be pivoted. This turning can, for example, by means of of an electric motor 11 are accomplished.

In Figure 2, the lower end position of the deflection member 2 ' shown in which the distance to the surface of the Spin bath liquid is largest. The upper end position of the Deflector 2 ', in which the distance to the surface of the Spinning bath liquid is the smallest is dashed shown. The one shown in FIG Embodiment of the container according to the invention is the maximum angle through which the deflection element is pivoted is 65 °.

The container 1 'is expediently provided with a lifting device (not shown) equipped with the height of the container 1 'and thus the width of the air gap LS, that is the Distance of the surface of the spin bath liquid to the stationary one Spinneret 7 ', can be adjusted.

The container according to the invention allows the draft angle α regardless of the width of the spinneret 7 'as small as possible hold. If a wide spinneret is used, as in Figure 2 is shown, by moving the arm 8 downwards the Distortion angle α reduced and thus the spinning security increase. With less wide spinnerets this can Deflector 2 'closer to the surface of the spinning bath liquid be positioned.

Another advantage of the container according to the invention is in that the start of spinning is easier to carry out. To the deflector is brought into the upper end position and the Air gap LS enlarged by moving the entire container down is moved. The filaments emerging from the spinneret 7 ' immerse in the relatively distant spinning bath passed over the deflector 2 'and through the oblique flanks 2'b and 2'c (see FIG. 3) on the Deflector bundled and held. The bundling is relieved when the deflector in the upper end position like this is that the area with the larger flank spacing the spinneret 7 'is facing. The bundle of filaments is pulled off diagonally upwards. During this process can the deflection element 2 'immediately by rotating the axis 9 downwards be lowered into the spin bath, reducing the draft angle downsized and at the same time by the obliquely employed Flanks the bundle of filament coulters is somewhat reinforced, since by turning the deflection element 2 'of the spinneret 7' now an area that has a smaller flank spacing has, whereby the bundling is strengthened. The redirected Filament bundle is a downstream take-off device (not shown) and by choosing a specific one Withdrawal speed of the desired titer due to delay in Air gap LS set.

Claims (7)

Container for holding spin bath liquid for Carrying out a dry / wet spinning process, at which process a spinning mass through a spinneret with high spinning hole density in a gaseous medium is extruded, forming a family of filaments which is delayed by the gaseous medium in the Spinning bath liquid can be introduced, thereby characterized in that a deflecting member in the container (1 ') (2 ') provided for bundling and deflecting the filaments which is pivotable in the vertical plane. Container according to claim 1, characterized in that the Deflector (2 ') a substantially cylindrical Body (2'a), that of two essentially annular flanks (2'b; 2'c) is limited. Container according to claim 2, characterized in that the planes formed by the flanks (2'b, 2'c) with one another enclose an angle between 7 ° and 30 °. Container according to one of claims 1 to 3, characterized in that it further comprises: (a) a line (3) for introducing spin bath liquid into the container (1 '), which line (3) is provided at the lower end of the container (1'), (b) an outlet (4) for spinning bath liquid, which is provided at the upper end of the container. Use of a container according to one of claims 1 to 4 for dry / wet spinning formable solutions from Cellulose in an aqueous tertiary amine oxide. Process for dry / wet spinning by extrusion of a Spinning mass through a spinneret with high spinning hole density in a gaseous medium, a group of Filaments is formed, which is delayed by the gaseous medium in a spin bath liquid introduced, bundled and guided over a deflection element are characterized in that the deflector (2 ') at such a distance from the spinneret (7') finds that the angle (α) between the outermost Filaments of the filament array and the perpendicular to the Spinneret (7 ') does not exceed 20 °. A method according to claim 6, characterized in that as a dope a formable solution of cellulose in an aqueous tertiary amine oxide is used.

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