SK104496A3 - Spinning device - 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

Technical field

The invention relates to a spinning apparatus for carrying out the amide oxide process according to a dry / wet spinning method with a spinneret having spinning holes for extruding filaments, a spinneret with a spinning bath liquid, a bundling element which is considered to be extruded in the spinning liquid. and an air gap, which is defined as the distance of the spinneret from the surface of the spin bath liquid.

BACKGROUND OF THE INVENTION

The dry / wet spinning technique generally consists in extruding the spinning mass through a molding tool, such as a spinneret, into a non-precipitating spinning medium, e.g. during consolidation, this medium is stretched and then passed into a spin bath liquid (precipitation bath) in which the filaments coagulate.

The amine oxide process generally refers to the formation of cellulose shaped bodies using a tertiary amine oxide. Here, the cellulose is dissolved in a mixture of tertiary amine oxide and water, the solution is shaped by a shaping tool and passed through an aqueous precipitation bath in which the cellulose precipitates. N-methylmorpholine-N-oxide (NMMO) is primarily used as the amine oxide. Other amine oxides are described, for example, in EP-A-0 553 070.

-2EP-AS - O 356,419.

An embodiment of the amine oxide process according to the dry / wet spinning process is known, for example, from DE-S-29 13 589.

WO 93/19230 and WO95 / (04173 of the applicant disclose a preferred embodiment of the amine oxide process and the cellulose fiber production apparatus according to which the cellulose solution is shaped in the tertiary amine oxide in a warm state and the shaped solution is fed through a gas medium ( The cooling is carried out immediately after shaping and consists essentially of blowing the cellulosic body through air horizontally. The method according to the invention allows the spinning of the cellulose solution to the cellulosic bath. having a high fiber density without adhering the fiberized fibers after exiting the spinneret.

DD-AS-218 121 also relates to a dry / wet spinning process for the production of cellulose fibers from cellulose solutions in a tertiary amine oxide. Also, according to this method, the cellulose solution is spun into the air gap, which is the distance between the spinneret and the surface of the spin bath liquid, when stretched and drawn into a water precipitation bath. DD-A-218 121 mentions that the air gap can be shortened without disadvantages for the spinning safety if polyalkylene ether is added to the cellulose solution prior to spinning. A small air gap is advantageous because the risk of sticking freshly extruded filaments is reduced.

EP-S-0 574 870 discloses a dry / wet spinning process for treating cellulose solutions in a tertiary amine oxide and points out the advantage

-3 to improve contacting a small air gap. In this manner, it is possible, according to the data in the description of this patent application, to spin with a small air gap and with a large number of spinning holes per unit area. In spite of these data, no spinning of filaments should occur in the spinning process. It is recommended to carry out the spinning filaments with liquid for the spinning bath in the spinning funnel. In a uniform flow with the filaments, the spin bath liquid is guided through the spinner funnel. The axis of the spinneret is substantially perpendicular to the plane of the spinneret, and the flow of liquid for the spinning bath is directed from top to bottom, the flow generally being generated by the free fall of liquid for the spinning bath.

According to EP-A-0 574 870, the elongation or stretching of the freshly extruded filaments is achieved in such a way that the filaments are accelerated to their draw-off speed by the spinning liquid flowing through the spinning funnel.

This previously known spinning device has the disadvantage that the spinning funnel tube, by virtue of its relatively small diameter, determines the filament bundle to be formed with respect to its overall cross-section an upper limit which is still set unsatisfactorily low for a highly technical embodiment of the method. Thus, in the experience of the applicant of the present application at a diameter of 6 mm, as for example disclosed in EP-AS 0 574 870, only the filament bundle consisting of a maximum of 100 filaments can be guided through the funnel, since liquid must also be transported through the funnel. for spinning bath. This in turn means that only a spinneret with a maximum of 100 spinnerets can be used when using such a spinneret.

If, on the other hand, a wide spinner is used

Thus, a nozzle with a thousand spinning orifices, such as described in the applicant's Austrian patent AT-B 397.392, must be a correspondingly larger funnel tube, which in turn must drain and circulate much more spinning liquid. This large amount of spin bath liquid leads to turbulent flows in the spin bath, which disrupts the dry / wet spinning process.

GB-A-1,017,855 discloses a dry / wet spinning apparatus for synthetic polymers. It is also recommended here to use a spinner funnel to allow the spin bath liquid to flow in a uniform stream with the extruded fibers. The spinneret is located approximately 0.5 cm above the surface of the spin bath.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a spinning device which allows the amine oxide process according to the dry / wet spinning process to be instrumentally simple and therefore feasible with good spinning (physical spinning safety), with good spinning being understood as high as possible withdrawal (at least possible titer) before breaking the fiber. Another measure for spinning is the time during which it can be spinning without any spinning error that would require a technical support measure. Furthermore, when using spinning nozzles with high orifice density alone, the sticking of the freshly extruded filaments in the air gap is to be avoided and as constant a titer as possible (noticeable titer variations) is achieved.

SUMMARY OF THE INVENTION

Spinning apparatus for carrying out the amine oxide process according to the dry / wet spinning method with

- has spinning holes for

- a spinnerette which extrudes the filaments,

- a blower through which the filaments can be cooled, immediately thereafter, the spinning holes,

- spinning liquid tank,

- a bundling element which is intended to bundle the extruded filaments in a spin bath liquid, and

- an air gap, defined as the distance of the spinneret from the surface of the liquid for the spinning bath, is characterized by:

- that the bundling element is spaced from the spinner at such a distance that the angle (a) which forms the filaments relative to the perpendicular to the surface of the spin bath liquid is at most 45 °, and

- that the relationship (h-1) is fulfilled

0.1 + 0.005 1 <= 0.7. d. ----- '* o h

extruded leaving the spinneret in which d _Q is the distance (mm) between the spinneret and its always adjacent spinneret on the spinneret, h is the distance (mm) of the bunching element from the spinneret, and 1 is the air gap,

0.4 mm <= d _Q <= 2 mm, and 0 mm <1 <60 mm.

It has been shown that the object of the invention can be solved if the spinning device used is designed such that the above two criteria (angle and maximum 45 ° as well as the above-mentioned inequalities) are met. When using spinnerets with a high orifice value, freshly extruded filaments need to be cooled immediately after leaving the spinnerets. However, this cooling is already known to the person skilled in the art (see, for example, WO 95/04173 of the applicant).

A preferred embodiment of the spinning device according to the invention is characterized in that the bundling element is formed as a return element on which the filaments are not only bundled but also inverted.

It has proven advantageous to design the return element so that it does not rotate when the filaments are reversed. Thus, according to this embodiment, the pulley or roller is not considered as a return element. In this way, it is achieved that the broken filaments on the return element are not wound. This facilitates the implementation of the amine oxide process.

A further preferred embodiment of the spinning device according to the invention is characterized in that the angle α does not exceed 20 °. It has been shown that for the spinning safety in the dry / wet spinning process it is absolutely important that the draw-in angle and the air gap are as small as possible and in particular do not exceed 20 °. Thereby, the risk of filaments sticking in the space between the spinneret and the spin bath surface can be minimized and the spinning safety increased.

The invention also relates to a spinning apparatus and an embodiment of an amine oxide dry / wet spinning process

- a spinnerette which extrudes the filaments,

- a blower through which the extruded filaments can be cooled immediately after leaving the spinning holes,

- spinning liquid tank,

- a return element which is intended to bundle and invert the extruded filaments in the spin bath liquid, and

an air gap, which is defined as the distance of the spinneret from the liquid for the spinning bath, characterized in that the return element is formed in a manner according to the method having spinning holes for

-That does not rotate when turning the filaments.

Another advantageous embodiment of the spinning device according to the invention consists in that the spinning nozzle is provided with:

- a nozzle body which is substantially rotationally symmetrical and has a cooling gas inlet at its center,

- inlet for cellulose solution,

a circular spinneret with spinneret holes, and

an impingement plate for controlling the flow of cooling gas to the filaments which are extruded from the spinning holes, since the flow of cooling gas extends substantially perpendicular to the filaments.

In this way, it can be spun with an even greater density of holes and at the same time it can be effectively prevented that the freshly extruded filaments stick together in the air gap. Cooling the annular system of filaments by blowing with cooling air is known from the applicant's publication WO 95/04173.

Another advantageous embodiment of the spinning device according to the invention is that the tank containing the liquid for the spinning bath is in connection with a lifting device by means of which the tank can be moved in a vertical direction opposite the spinnerette there and back, changing the distance 1 and the bundling element is arranged such that the distance h remains constant despite this movement.

Overview of the figures in the drawing

BRIEF DESCRIPTION OF THE DRAWINGS The invention is further elucidated with reference to the accompanying drawings, in which: FIG. 1, FIG. 2 and FIG. 3 show a general illustration of the dry / wet spinning process,

-8i with quantities important for the relationship according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 1, the spinning bath liquid tank is indicated by 1, the surface of the spin bath liquid being denoted by 1a. In the spinning process, the spinning mass is extruded through the spinnerette and the extruded filaments 4, 5 are drawn through the air gap 1 into the spinning liquid in which they coagulate. On the return pipe 2, which is a non-rotatable, cylindrical rod, the coagulated filaments are bundled, inverted and oblique upwardly drawn. The air gap 1 is defined as the distance of the underside of the spinneret 2 from the surface 1a of the spin bath liquid. The angle defined above by the filaments relative to the perpendicular to the surface for the spin bath is denoted < χ.

i I

Reference numeral 4 denotes a filament that comes from the spinning orifice located at the outer edge of the annulus formed by the spinning orifices in the spinneret 2 / is the radius (mm) of the circle that outwardly delimits the annulus formed by the spinning orifices. <X _H indicates the distance of the spinneret hole to his zvlákňovačiernu adjacent the opening 2, while it is always meant the distance between the centers of two adjacent spinning holes, h is the distance of the return element from the spinneret 2 ^ 1, and the air gap.

According to the embodiment described in FIG. 1, the reservoir 1 stands on a lifting device (not shown here) which can be moved vertically by the reservoir and thus the air gap size (T) can be easily changed

It has proved to be particularly advantageous that the return element 2 is not fixed to the container 1, but is intended to be such that:

-Adjustment space 1 and FIG.

with the reservoir 1 can be moved and at the same time the distances 4 remain constant. In this simple manner, the air can be varied while keeping the distance h constant. Fig. show embodiments of such a type of spinning device according to the invention.

Fig. 2 essentially shows the spinning device of FIG. 1, wherein like parts have been designated with the same reference numerals. The non-rotatable return element 2 is connected via a rigid arm 6 to a fixed element 7 which is not connected to the reservoir, so that when the reservoir 1 is raised or lowered, the element 7 does not move with it. For example, the element 7 may be a wall. In FIG. 2 shows two positions of the reservoir 1, the lower position being indicated by dotted lines. The device for lifting and lowering the reservoir 1 is not shown. FIG.

it is clear that by lifting and lowering the reservoir 1 the air gap can be shortened or extended, while at the same time the distance h remains the same.

Fig. 3 shows a further embodiment of the spinning device according to the invention. In this embodiment, the return element 2 is anchored by means of a rigid arm 8 on the floor 8. The arm 2 protrudes by a corresponding opening 11 which is provided in the container 1. In order not to lose any liquid from the reservoir 1, a seal 10 is provided for sealing, which simply closes when the reservoir 1 is lowered by means of a device (not shown).

The following Examples 1, 2, 3 and 4 illustrate the invention

The examples 1 and 2 illustrate the effect of the angles on the fiberizability of the cellulose solutions. Example 4 illustrates the advantageous effect of a non-rotatable restoring element on spinning.

-10Example 1

A spinning device that essentially corresponded to FIG. 1, but as a bundling element according to EP-A 0 574 870. As used is that described in WO 95/04173, the disclosure of which is incorporated herein by reference.

This previously known spinnerette (number of holes:

spinning funnel used spinneret was

100 mm, nozzle outer diameter 145 mm) has a nozzle body formed essentially rotationally symmetrically, having

3960, hole diameter (outer row of holes)

supply for cooling gas, supply for cellulose solutions (13,

5% cellulose, temperature 120 ° C), a round deep-drawn spinner made of heat-treated steel with spinning holes, where the spinneret is formed in a tub-shaped cross-section, and an impingement plate to control the cooling gas flow to cellulosic filaments which are extruded from spinneries 0.025 g / min) so that the cooling gas stream (24 m ³ / h) hits the extruded cellulose filaments substantially perpendicularly. The spinning orifices in the spinnerette j have a substantially uniform spacing between them (aperture - aperture d _o : 1000 μαι). The air gap 1 had a length of 15 mm. The air in the air gap was at a temperature

24.5 ° C and water content 4.5 g water / kg air.

|| and

Several spinning experiments were carried out, with the same air gap l changing the distance, h of the funnel bundling point (transition from the cylindrical tube to the funnel itself) from the surface,

0.1+ 0.005 (s 1 = 15 = 1000) of the spinneret such that (h-1) ¹ <= 0.7.d _o .--------, h

In a further experiment, the maximum attainable end draw, i.e. the maximum draw speed of the filaments at breaking the fiber, was measured. The results

h (mm) angle a 240 16.8 190 20.9 140 27.4 90 38.8 70 46, 0 40 61.1

are shown in Table 1:

Table ending from t; ah (m / min)

42

41 29 0

It can be seen from Table 1 that no reduction in the ultimate draw-off speed can be observed up to an angle of about 40 °, and thus no deterioration of the spinability. However, from an angle of 45 °, the maximum retraction speed decreases markedly. At an angle of about 61 °, the solution is no longer fiberizable.

EXAMPLE 2 The apparatus used for the spinning was used Fig. 2, and as I the spinneret was again schematically described in WO 95/04173 (number of holes 28.392, hole diameter 100 gm, nozzle outer diameter (outer row of holes (d: 155 μτα, hole-hole spacing d _o : 500) / xm).

The cellulose solution used contained 13.5% cellulose and had a temperature of 120 ° C. The discharge] was 0.025 g / min. The air gap 1 had a length of 20 mm. The air in the air gap was at a temperature of 12 ° C and a water content of 5 g water / kg air.

The filaments were turned on a cylindrical non-rotating rod; and

2. and pulled up at an angle from the spinning bath.

At the same air gap 1, the distance h was varied and the maximum end draw speed and angle were determined analogously to Example 1. The results are shown in Table 2.

-12Table 2

h (m, m) angle α (°) final draft (m / min) 345 13 18 165 25 18 115 34 ^j 18 75 46 4

As can be seen in Table 2, there is no reduction in the maximum end draw speed when the angle α is changed from 13 ° to 34 °. However, if the angle qi increases to 46 °, then i

end towing speed, i.e. ¹ fiberizability, drastically reduced. If the distance h is further reduced, the angle g is increased, the solution can no longer be spun.

Example 3

The same spinner was used as described in Example 2, but the air gap 1 was set constant at 30 mm.

Again the distance h was changed. Due to the occurrence of spinning errors (tearing of the filaments, extreme bonding of the filaments together), the safety of spinning of the solution under predetermined conditions was characterized.

I ¹

A high spinability is given if virtually no spinning error occurs in a time interval of more than 15 minutes. If more spinning errors occur within a time interval of 15 minutes or earlier, spinning on a technical scale is only possible with a permanent technical support measure.

v j l

Furthermore, spinning is characterized by a time stamp, wherein in the following Table 3,> 15 min indicates that good spinning has been given (virtually no spinning errors within 15 minutes). For example, <10 min means that 10 minutes after the start of spinning, there were large spinning errors that

I force interruption of spinning.

spinnability

-13Ί;

Table 3

Ih (mm) angle and (°) i

245 13 > 15 min 165 25 i > 15 min 115 34 > 15 min 100 38 10-15 min 85 42! <10 min

From Table 3 it can be seen that up to a distance h of 115 mm good spinning is given. However, since h is even smaller, it is no longer fulfilled the relationship established by the invention, and the spinability deteriorates drastically. This is the case with both last attempts. This deterioration of the spinning behavior in this case already occurs at an angle and well below 45 [deg.].

Example 4

In a pilot plant for the production of cellulosic fibers according to the amine oxide process, the spinning process of the spinning bath in the spinning bath has also been investigated in many individual experiments with the spinning apparatus of the invention.

Rotary symmetrical rotary return members of various embodiments (glass rod pulleys having a smooth or ribbed surface) were tested. In these experiments, it has always been found that, as soon as the return element rotates about its own axis, the filaments wind up at the return roller within a short period of time. The reason for the winding is obviously that in the spinning bath there is sometimes a single tearing of the fibers which are picked up by the rotating return roller itself, are guided together from the return roller and the coiling of other filaments leads to an increasing winding; In this case, the spinning filaments are damaged because the filaments wound on the deflection roller must be removed by mechanical action again, which leads to a deterioration of the end product.

It has been shown that the spinning procedure must be interrupted in less than 30 minutes in order to remove the fibers wound on the spinning roller when using the swivel pulley.

Since the return element is prevented from rotating when the other parameters are removed, for example, because it is fixedly mounted, virtually no winding takes place. It has been shown that in this way the continuous spinning process can be maintained for more than a few hours. The use of rotatable return elements must therefore be avoided. In order to enable trouble-free operation, it is necessary that all the return elements are preferably non-rotatable.

Claims (7)

A spinning apparatus for carrying out the amine oxide process according to the dry / wet spinning method with - a spinnerette having spinning holes for extruding the filaments, - a blower through which the extruded filaments can be cooled immediately after leaving the spinning holes, - spinning liquid tank, - a bundling element which is intended to bundle the extruded filaments in a spin bath liquid, and - an air gap, defined as the distance of the spinneret from the surface of the spinning bath liquid, - that the bundling element ( (2) is spaced from the spinneret (3) at a distance such that the angle (a) formed by the filaments relative to the perpendicular to the spinning liquid surface (1a) is at most 45 °, and - that the relationship (h-1) is fulfilled 0.1 + 0.005 1 <= 0.7.d _o -----, h wherein (d _Q ) is the distance (mm) between the spinning orifice and its always adjacent spinning orifice on the spinnerette (3), (h) is the distance (mm) of the bundle member (2) from the spinnerette (3), and (1) is the air gap, where 0.4 mm <= d <= 2 mm, and 0 mm <1 <60 mm. -162. Spinning device according to claim 1, characterized in that the bundling element (2) is designed as a return element (2) on which the filaments (4, 5) are not only bundled but also inverted. Spinning device according to claim 2, characterized in that the return element (2) is designed so that it does not rotate when the filaments (4, 5) are reversed. Spinning device according to one of Claims 1 to 3, characterized in that the angle (α) is at most 20 °. 5. A spinning apparatus for carrying out the amine oxide process according to the dry / wet spinning method with - a spinnerette having spinning holes for extruding the filaments, - a blower through which the extruded filaments can be cooled immediately after they have left the spinning holes, - spinning liquid tank, - a return element which is intended to bundle and invert the extruded filaments in the spin bath liquid, and - an air gap, which is defined as the distance of the spinneret from the liquid for the spinning bath, characterized in that the return element (2) is designed so that it does not rotate when the filaments (4, 5) are reversed. 6. A spinning device according to claim 1 5, characterized in that the spinning -17the nipple is provided with: - a nozzle body made in symmetrical shape and having cooling gas in it, - inlet for cellulose solution, a circular spinneret through holes, and a filament gas impingement plate, a substantially rotating center inlet for the spinning control of the cooling stream which is extruded from the spinning holes, so that the cooling gas stream extends substantially perpendicular to the filaments. Spinning device according to any one of claims 1 to 6, characterized in that the tank containing the spinning bath liquid is in connection with a lifting device by means of which the tank can be moved in a vertical direction towards the spinning nozzle back and forth, thereby changing the distance (1), and the bundling element is arranged such that the distance (h) remains constant despite this movement.