KR20020093934A - Method for spinning a spinning solution and spinning head - Google Patents

Abstract

The present invention relates to a spinning head (8) for spinning a spinning dope, which is provided with a tubular, thin-walled spinning capillary (7) having a discharge opening (94). The spinning dope used is e.g. a mixture of cellulose, tertiary amine oxide and water. In order to reduce the fibrillation tendency of the fibres spun by means of the spinning head and in order to increase the non-looping property, the present invention is so conceived that the spinning capillary (7) is heated directly close to the discharge cross-section (94). By means of this simple measure, it is possible to reduce the fibrillation tendency and to increase the non-looping property.

Description

Method for spinning a spinning solution and spinning head

Such methods and apparatus are well known from International Publication No. WO99 / 47733. In the above reference, the spinning capillary is followed by the pre-capillary in the flow direction of the pre-capillary (referred to as the capillary in the reference) and the spinning dope (referred to as the orifice in the reference). It is depicted as including a capillary. The pre-capital and spinning capillaries are produced from two parts of metal blocks. The diameter of the pre-capillary is 1.2 to 2.5 times the spinning capillary.

Reference The spinning head of WO 99/47733 has openings in the area of the pre-capillary, which openings are used to receive the heating device. The heating device functions to heat the metal block of the spinning head in the region of the pre-capillary.

Reference The spinning block of WO 99/47733 is provided by a gas chamber containing a heated gas surrounding the spinning dope which flows out of the spinning head substantially parallel to the spinning dope discharged from the spinning-dope discharge opening. Surrounded.

The driving temperature of the spinning head and spinning capillary in the region of the pre-capillary ranges from 70 to 140 ° C. The temperature of the discharged gas is preferably 70 ° C., which is lower than the temperature of the spinning head.

Reference The spinning head according to WO 99/47733 has the disadvantage that the hole density can be realized because of the structural design of the spinning head described in this reference. A further disadvantage is the fact that temperature can be affected in the region of the pre-capillary.

Due to the high cellulose concentration and high structural viscosity used when NMO / water / cellulose solutions are spun, it is necessary to influence the spinning temperature. In addition, attention is paid to improving the uniformity of the temperature distribution and attention to the requirements not fulfilled in the case of spinning nozzles and heating systems described in reference WO 99/47733.

In view of reference WO 99/47733, the aim to be achieved is to improve spinning heads according to the general clause in such a way that the spun fibers have a low fibrillation tendency and high non-looping properties. will be.

The tendency to microfibrillation is determined by the so-called shaking test ("shaking test"). Shaking experiments are described in the periodic "Chemiefaser Textilindustrie" page 43/95 (1993), page 879 and reference WO 96/07779.

In the above experiments, fibers having a standard length are shaken for a predetermined time in the presence of glass beads. The degree of fibrosis of the fibers is determined by microscopic examination: if a large amount of split-off fibrils is found through the microscope, this means that the fibrosis value is high and consequently of poor quality. do.

With respect to the method mentioned at the outset, this object is close to the spinning-dope discharge opening and the wall of the spinning capillary is heated to a temperature higher than the core temperature of the spinning dope in the spinning capillary at least in the cross-sectional direction. It is achieved by the features of the invention.

Surprisingly enough, the fact that due to the influence on the temperature distribution of the solution during extrusion through spinning capillaries, cellulosic fibers, which are mostly free of fine fibers and have excellent fiber properties, i.e. good non-looping properties, can be produced on the basis of favorable flow behavior. This was found.

In the case of the spinning head mentioned at the outset, this aim is to ensure that, in the region close to the spinning-dope discharge opening, when the spinning head is in operation, the wall temperature of the spinning capacitor is higher than the core temperature of the spinning dope. It is achieved by the features of the present invention.

By this simple measurement, cellulosic fibers having a lower tendency to finer fiber and higher non-looping properties than prior art fibers can be produced.

In the most suitable prior art, spinning head according to WO 99/47733, the capillary is heated, but the spinning capillary extending to the spinning-dope discharge opening is not heated. The pre-capillary has a larger diameter than the capillary. Due to the abrupt change in the cross section between the pre-capillary and the capillary, the temperature distribution in the spinning dope installed in the pre-capillary is no longer favorable for the spinning dope. To be prevented from developing.

Furthermore, the device according to WO 99/47733 does not offer the possibility of heating the capillary wall to a temperature higher than the core temperature of the spinning dope. Because of the long behavior length of the pre-capillary and the low flow rate of the spinning dope in the pre-capillary, the spinning dope will be heated from the pre-capillary to the temperature of the pre-capillary wall. There are two reasons for the fact that the wall temperature of the capillary of WO99 / 47733 is lower than the temperature of the spinning dope.

Firstly, in the spinning head of WO 99/47733, the gas discharged from the gas chamber flows through the annular gap along the outer wall of the capillary. The temperature of this gas is lower than that of the spinning dope. In the case of the apparatus of WO 99/47733, the capillary region close to the discharge opening is actually cooled by this gas to a temperature below the core temperature of the spinning dope.

Secondly, the capillary wall close to the discharge opening is only indirectly heated by the heating head of the spinning head according to WO 99/47733: the heating device is arranged close to the pre-capillary and mainly for the pre-capillary. Works. The downstream capillary is only heated indirectly through the heating of the capillary block. In the case of a spinning head according to WO 99/47733, the wall temperature of the capital near the discharge opening will always be lower than the temperature of the pre-capital.

The present invention relates to a method of spinning a spinning dope. The spinning dope comprises tertiary amine oxides, water and cellulose, wherein the method supplies the spinning dope continuously or discontinuously from the spinning dope reservoir to the spinning head and at least one of the spinning dope. Delivering to the spinning head through a spinning capillary, wherein the spinning capillary has at its downstream end a spinning-dope discharge opening through which the spinning dope is discharged from the spinning head and have.

The present invention also relates to a spinning head for spinning a spinning dope comprising a tertiary amine oxide, flowing through the spinning head, the spinning head comprising at least one spinning capillary, wherein the spinning capillary Further comprises a heating device at its downstream end, with a spinning-doped discharge opening through which the spinning dope exits the spinning head, and which acts on the spinning dope.

The term spinning capillary here means the last part of the spinning head through which the spinning dope flows and defines the spinning-doped outlet opening. The spinning yarn is formed by spinning capillaries.

1 is a configuration diagram of a spinning system.

2 is a cross-sectional view of a spinning head according to a first embodiment of the present invention.

3 is a cross sectional view of a spinning head according to a second embodiment of the present invention;

4 is a cross-sectional view of a spinning head according to a third embodiment of the present invention.

5 is a cross-sectional view of a spinning head according to a fourth embodiment of the present invention.

According to a particularly advantageous embodiment of the invention, the walls of the spinning capital can be indirectly heated by a heating device. In the case of direct heating, the heater acts directly against the spinning capital wall. Such direct heating is not present in the case of the conventional spinning heads disclosed in WO 99/47733. In the case of this spinning head, the spinning capital walls are indirectly heated via a spinning block with a large mass. However, since there are no large inertial masses that can respond slowly to temperature changes, direct heating of the spinning capital wall has the advantage that the temperature of the wall can be controlled more accurately with a faster response. .

In order to precisely adjust the wall temperature of the spinning capacities and to precisely control the process, a temperature controller for adjusting the wall temperature of the spinning capacities to an adjustable value may be provided as a more advantageous embodiment. Such a thermoregulator allows the wall temperature to be automatically adapted to changes in the spinning process, ie other spinning dopes or other spinning-head structures.

According to one embodiment, the wall temperature of the spinning capital is adjustable according to the mass flow rate of the spinning dope through the spinning capital. The thermal transition from the capillary increases in response to the mass flow rate, so that the heating of the capillary wall must be adapted. In this regard, it would be advantageous when changes in mass flow rate through the spinning capital can be compensated by adjusting the wall temperature.

According to another advantageous embodiment, the wall temperature of the spinning capillary may be adjusted according to the spinning pressure in the spinning dope, preferably in accordance with the spinning pressure of the spinning dope in the capillary. Flow rate, consequently, the heat transfer in the spinning dope also depends on the spinning pressure, i.e. the flow rate at the spinning dope: The flow rate of the spinning dope through the spinning capital increases with increasing spinning pressure. Also in this case, it would be advantageous when the changes in spinning pressure could be compensated by adjusting the wall temperature of the spinning capital.

The tendency to finer fiber can be reduced particularly according to another advantageous embodiment when the heating of the spinning capillary wall creates a predetermined temperature profile over the flow cross section of the spinning capillary when the spinning head is in operation. By this temperature profile, the velocity profile of the spinning dope in the spinning capacitor is intentionally influenced based on the temperature dependent viscosity of the spinning dope. In particular, when the capillary wall is heated heavily, it will be possible to reduce the viscosity of the spinning dope to a substantial extent in the wall region. Such heating will reduce the wall friction of the spinning dope and lead to a more complete and wider flow profile in the capillary: the distribution of flow velocity across the flow cross section no longer has a pipe flow of a severely curved profile. It has a wide maximum, reaching a wall of spinning capillaries in a nearly constant fashion. In this method, the microfibrillation tendency can be improved by affecting the flow profile through the wall temperature.

The effect of the wall temperature on the flow profile of the spinning dope in the spinning capital is that the predetermined temperature profile of the spinning capital wall heats the spinning capital wall when the spinning head is in operation. When it can be adjusted in the flow direction of the dope, it can be increased even more according to an advantageous embodiment. For this embodiment, the velocity profile in the spinning capital is affected by intentionally changing the temperature profile in the flow direction. The formation of the pipe flow profile is reliably avoided and the flow profile can be further optimized by adapting the temperature distribution in the flow direction.

For this purpose, a number of independently driven heating devices can be provided on the spinning capital in the flow direction.

Particularly uniform heating of the spinning capillary wall can be achieved when heated heating fluid flows around the wall of the spinning capillary from the outside thereof. Reference In contrast to electrical heating, a type described in WO 99/47733, a sharp change in the spatial temperature distribution will not occur in the case of heating by fluid. In addition, local overheating can also be avoided. The temperature of the heating fluid is at least 100 ° C, preferably about 150 ° C. The temperature of the heating fluid may advantageously be in the range of 50 ° C., 80 ° C. or 100 ° C., and 150 ° C. or 180 ° C. Due to the high flow rate at the end capillary of the spinning head, the wall temperature of the spinning capillary can even exceed the decomposition temperature of the spinning dope. The residence time of the spinning dope in the spinning capacitor is not long enough for the spinning dope to reach the decomposition temperature.

According to another embodiment of the invention, at least one temperature sensor may be provided for detecting the temperature of the capillary wall and / or the temperature of the spinning dope in the region of the capillary wall. This temperature sensor is configured to output an electrical signal representative of the capillary wall temperature. With the help of such a sensor, the temperature of the capillary wall can be determined at any time, directly or indirectly. This can be used to provide a signal to a regulating device in which the wall temperature can be adjusted. For this purpose, the thermostat will change the temperature of the heating fluid present in a suitable way.

When a heating fluid is used, at least one temperature sensor may be provided according to another advantageous embodiment, the temperature sensor detecting the temperature of the heating fluid and outputting the temperature of the heating fluid to the controller in the form of an electrical signal. To be used. In this embodiment, the wall temperature of the spinning capital can be determined and adjusted through the detection of the heating fluid temperature.

As far as the spinning head is concerned, it would be particularly advantageous when the area of the spinning capillary wall, heated by the heating device and whose temperature is above the core temperature of the spinning dope, essentially reaches the spinning dope outlet opening. The spinning dope exit opening is a special critical point where high wall temperatures will affect the tendency of fibrosis in a particularly advantageous direction. In particular, it has been found that jet expansion, so-called strand expansion, immediately after discharge of the spinning dope from the discharge opening can be suppressed by heating the discharge opening. This results in an improved surface structure of the spun fibers, and consequently the non-looping properties will be further increased and the fibrosis tendency will be further reduced.

According to another advantageous embodiment, the area of the spinning capital wall which is heated by the heating device and whose temperature is above the core temperature of the spinning dope may extend essentially over the entire length of the spinning capital. For this embodiment, the entire spinning capillary can be heated: due to the reduced viscosity of the spinning dope near the wall and due to the moving distance of the spinning capillary, this is due to a sufficient velocity profile for the transverse cross section of the spinning capillary. It will come to full formation.

In order to be able to quickly and intentionally control the wall temperature and the temperature of the spinning dope flowing near the wall, the temperature of the spinning capillary wall must be able to be controlled quickly by the heating device and react quickly to temperature changes. According to yet another embodiment, this is implemented as a spinning-capillary tube in the form of a substantially thin-walled tube in which the spinning capillary is mounted, with the heating device in relation to the wall region of the spinning capillary tube close to the spinning dope outlet opening. It can be achieved by features that act directly. Due to the thin-walled structural design of the spinning capital, since there is no inertial mass, the wall temperature will respond quickly in response to the temperature change of the heater. Fast response will be further ensured from the fact that the heater acts directly on the thin-walled spinning capacitor. It will be advantageous when the wall thickness of the spinning capillary tube is less than 200 μm, preferably less than 150 μm.

According to a further embodiment, the spinning dope outlet opening of the spinning capillary tube has a gap opening in at least the cross-sectional direction and the direction of the spinning dope discharged from the spinning dope outlet opening when the spinning head is in drive. It can be surrounded by a conveying fluid necessarily flowing out from the gap opening. The conveying fluid surrounds the spinning dope jets discharged from the discharge openings of the spinning capacities to reduce abrupt velocity changes on the outer surface of the jets. This has the effect that the jet is stabilized and the flow on the outer surface is quiet. When the spinning head is in drive, the speed of the conveying fluid flowing out of the gap opening can substantially correspond to the speed of spinning dope exiting from the spinning dope discharge opening.

One embodiment of the spinning head is configured such that the spinning capillary tube is surrounded by a heating chamber containing heating fluid near the spinning dope outlet opening. This will be particularly advantageous when the heating chamber is in communication with the gap opening. This allows the heating fluid to flow through the gap opening and sweep over the area of the spinning capillary wall located near the discharge cross section. In this way the spinning capital wall can be heated up to the discharge cross section.

When the heating fluid is discharged from the gap opening at a suitable speed, it can simultaneously function as a transfer fluid. Therefore, it would be unnecessary to provide a separate transfer fluid for stabilizing spinning dope jets.

In order to form a stable and sufficient flow profile, the length of travel in the spinning capital should be as long as possible. Therefore, the ratio of the length to the diameter of the spinning capital should be as large as possible. According to an advantageous embodiment of the spinning capital, the length of the spinning capital is at least 20 to 150 times longer than its diameter. The length taking into account this ratio may be the length through which the spinning dope flows, and the diameter may be the inner diameter of the spinning capital.

In this way, according to a more advantageous embodiment of the invention, the flow cross section of the gap through which the fluid is discharged parallel to the spinning dope can be changed by means of a variable housing, ie variable vanes. Therefore, the velocity of the fluid exiting the gap can be varied according to each spinning operation and each spinning jet velocity and thickness.

The spinning capillary can also be directly heated by an electrical heating element surrounding the spinning capillary.

According to a more advantageous embodiment, the spinning capillary can be implemented as a precision steel tube. It may have a circular discharge opening. The diameter of the discharge opening may be less than 500 μm, preferably less than 250 μm. If for special use, i.e., spinning the spinning material to produce lyocell fibers, the diameter may range from 100 μm to less than 75 μm.

The spinning head may be installed in a spinning system having a pressure equalization vessel. The pressure equalization vessel contains spinning dope with tertiary amine oxides. The spinning system includes a spinning head, in which the spinning dope can be woven using it to produce spinning filaments, and further comprising a spinning dope conduit through which the spinning dope is sent to the spinning head. This spinning system performs the method according to the invention.

The invention also relates to a product produced by the method according to the invention, a spinning head or a spinning system according to the invention: the product is characterized by improved non-looping properties and lower tendency to fibrils, It may have the form of staple fibers, woven fibers, or films / sheets.

Next, the method and the structural design of the spinning head and the driving mode according to the invention are explained on the basis of the embodiments.

Thereby a spinning system 1 in which the method according to the invention is carried out is shown in FIG. 1.

The spinning dope storage vessel or reactor 2 contains spinning dope 3 with high viscosity. Spinning dope 3 comprises a solution of tertiary amine oxides, ie cellulose, water and N-methylmorpholine-N-oxide (NMMO).

The spinning dope is transferred by the pump 4 from the spinning dope vessel 2 to the manifold / distributor block 6 via the spinning dope conduit 4 'and the pressure equalization vessel 5. The manifold block 6 and the spinning capes 7 are part of the spinning head 8.

The pressure equalization vessel functions to equalize possible pressure and / or volume flow rate changes within the spinning dope conduit 4 'and to ensure a uniform supply of spinning dope to the spinning head 8.

High viscosity spinning dope jets 9 exit the spinning head 8 at high speed. After exiting the spinning head 8, these spinning dope jets 9 flow through the air gap 10 or a non-precipitative medium. At this stage, the spinning dope is accelerated and consequently drawn.

Spinning dope jets are then introduced into bath 11 containing a nonsolvent or aqueous amine oxide solution. From the settling tank 11, the spinning dope is drawn in the form of fibers by a drawing device 12.

Next, the structural design of the spinning head 8 according to the first embodiment of the present invention is explained with reference to FIG.

When the spinning head is heated, the spinning head 8 is coupled to the frame 5 and insulated by the thermal barrier material 52 so that no heat loss occurs.

The spinning head 8 has a modular structural design comprising a manifold block 6, a substantially disk or plate shaped pressure distribution plate 54, a substantially disk or plate shaped spinning nozzle body 56, The spinning nozzle body 56 is equipped with a dispenser space 56a, at least one spinning capital 7 and a holding device 60.

The pressure distribution plate 54 of the spinning nozzle body 56 is fixed by the holding device 60 on the manifold block 6 in the direction of the central axis M of the spinning head. For this purpose, the holding device 60 defines an annular or slotted opening in which the pressure distribution plate 54 and the spinning nozzle body 56 are accommodated. A shoulder 60a is formed at one end of the annular opening, which engages the auxiliary opening 60b of the spinning nozzle body 56.

Spinning nozzle body 56 lies on one of its end faces in essentially front contact on pressure distribution plate 54. A sealing member 62 is provided on the end face of the nozzle body 56 such that the spinning dope cannot escape between the pressure distribution plate 54 and the spinning nozzle body 56.

The end face of the pressure distribution plate 54, which is spaced apart from the spinning nozzle body 56, is necessarily adjacent in full contact on the manifold block 6. In addition, this end face has a sealing member 62 therein so that the spinning dope does not escape between the manifold block 6 and the pressure distribution plate.

The holding device 60 is applied towards the manifold block 6 by the screw means 64 which engage the holding device 60. The shoulder 60a of the holding device 60 pressurizes each opening 60b of the nozzle body 56. The nozzle body 56 redirects this pressure to the manifold block 6 via the pressure distribution plate 54. In this way, the pressure distribution plate 54 and the nozzle body 56 are fixed and hermetically coupled on the manifold block 6 and, when needed for replacement or maintenance by other structures, loosen the screw means 64 easily. Can be replaced.

Spinning capital 7 is coupled to spinning nozzle body 56. Spinning capillaries have a circular cross section and are implemented in the form of a tube whose inner diameter is less than 50 μm.

The inner diameter of the spinning capes 7 is constant over its entire length.

The tubes used for spinning caps 7 are precision steel tubes derived from the medical engineering sector whose inner diameter is less than 500 μm and in part less than 250 μm. In particular, for lyocell fibers, it would be possible to provide an inner diameter of less than 100 μm to less than 50 μm.

The spinning capital 7 is a thin wall and has a wall thickness of up to 200 μm. The length of the spinning capital is at least 20 times the inner diameter, preferably at least 150 times. The test results showed that the tendency of the fibrils of fibers to decrease with increasing length / inner diameter ratio of the spinning capillaries.

Typically, a plurality of spinning caps 7 are arranged side by side on the spinning head 8 or in a plurality of rows relative to each other. As can be seen in Figure 1, a plurality of the above mentioned spinning heads can be arranged in any arrangement mode to define an economical production apparatus. Each nozzle body 56 comprises a plurality of spinning caps 7 arranged in a single row or in an elongate or annular structure in several rows.

In order to ensure a uniform flow into the capacities 7, the distributor space 56a is embodied as a single groove or a plurality of rows of V grooves, as an elongated or annular V-shaped groove. The pressure distribution plate 54 is located above the distributor space 56a made of the V-shaped groove.

The spinning capital 7 is surrounded by an inner housing 66 and an outer housing 68.

The inner housing 66, together with the outer surface 7a of the spinning capital, defines a heating chamber 70 which is sealed outwardly and through which a heating fluid flows. The inner housing 66 and the nozzle body 56 define a unit. The outer housing 68 follows the device consisting of the nozzle body 56 and the inner housing 66. The spinning capacitor 7 protrudes slightly out of the inner housing 66 and the outer housing 68.

The outer housing 68 surrounds the inner housing 66 to define an additional heating chamber 72 with the outer surface of the inner housing 66: however, in contrast to the heating chamber 70, the heating chamber 72 Is opened outward. The heating chamber 72 defines a gap 74 surrounding the end of the spinning capital 7 arranged opposite to the spinning head. The heating fluid also flows through this heating chamber 72 and flows substantially parallel to the central axis M through the gap.

In order to change the geometry of the gap 74, the outer housing 68 is supported on the inner housing 66 so that it can be displaced in the direction of the central axis M.

According to the embodiment of FIG. 2, the same kind of heating fluid can be used for both chambers 70, 72. This heating fluid can be heated to 150 ° C. via a heat exchanger (not shown) as a gas inert to the spinning dope. Alternatively, other types of heating fluids may be used for the chambers 70, 72. The heating chamber 70 defines a heating device for the spinning capital 7.

The manifold block 6 and the holding device 60 are embodied as substantially large blocks with large masses, which are heating channels 76, 78, 80 for hot water, hot air, heat transfer oil and steam. Or optionally mounted rod-shaped heating elements. Due to the large mass and heat shielding of the manifold block 6 and the holding device 60, only small changes will occur at the drive temperature of the manifold block 6 and the holding device 60.

Next, the function of the spinning block according to the present invention is described.

The spinning dope is equipped with a through disk or plate 86 having flow openings 88 formed therein via a supply line 82 connected to the spinning dope supply via a sealing means 83. Flow through manifold block 6 to stabilization chamber 84. Stabilization chamber 84 and through disk 86 are formed by pressure distribution plate 54. When viewed in the flow direction, the filtration device 90 is located in front of the through disk 86. Stabilization chamber 84, through disk 86 and filtration device 90 extend over all spinning caps 7.

Due to the flow transverse cross section of the stabilization chamber 84 enlarged to a greater extent than the supply line 82, the flow rate of the spinning dope is reduced and the flow becomes more uniform. In addition, the spinning dope flows through the openings 88 of the filtration device 90 and the pressure distribution plate 54 so that the flow and pressure profile will become even more uniform across the flow cross section, all the capillaries 7 will be supplied evenly.

From the stabilization chamber 84, the spinning dope flows through the pressure distribution plate in the spinning head 8 and enters the dispenser space 56a defined by the spinning nozzle body 56. In the distributor space 56a, the flow cross section decreases gradually along the flow direction. This has the effect that the spinning dope is accelerated and the flow cross section is gradually reduced to the flow cross section of the spinning capes 7.

When viewed in the flow direction, the spinning caplets 7 follow the distributor space 56a and the spinning caplets 7 end in the spinning-dope outlet openings 94 in the flow direction. This spinning dope is discharged from the spinning head through the spinning-dope discharge opening 94 at high velocity and high mass flow rate, respectively. Typical mass flow rates per spinning capital are from 0.03 to 0.5 g / min. Higher flow rates up to 1.5 g / min are possible at higher heating temperatures of the spinning capacities. The spinning dope pressure can reach 400 bar.

In order to drive the spinning head 8, it is important that it is maintained at the drive temperature as the spinning dope flows through the spinning head. For this purpose, the heating channels 76, 78, 80 already briefly mentioned above are provided in the manifold block 6 and the holding device 60.

Manifold block heating channels 76 are disposed proximate to supply line 82 to maintain the spinning dope in supply line 82 at a drive temperature. Heating fluid, such as hot water, heat transfer oil or water vapor, flows through the heating channels 76.

The heating channel 78 will be disposed far below in the area of the holding device 60 to heat the dispenser space 56a before the spinning material enters the capital 7. Heating fluid, such as hot air, hot water, heat transfer oil or water vapor, also flows through the heating element 78.

Optionally, a second manifold block heating element 80 may be provided attached to a spinning head portion located opposite the spinning dope discharge opening 94. In the embodiment according to FIG. 2, the manifold block heating element 80 functions to heat upstream of the supply line 82.

Heating channels 76, 78, 80 may be connected to a common heating circuit, or they may define separate heating circuits. Heating circuits of heating channels 76, 78, 80 may also be connected to the heating chamber.

In the first embodiment with reference to FIG. 2, the tendency of microfibrillation is reduced by the fact that the spinning capital 7 is heated from the outside in the region of the outlet opening 94. This is achieved by the fact that the heating fluid in the heating chamber 70 flows around the outer surface of the spinning capital 7 to directly heat the spinning capital 7. Due to the fact that the spinning capital 7 has large outer surfaces and thin walls in terms of length, high heat transfer occurs from the heating fluid to the spinning dope via the spinning capital walls. In order to obtain the best possible heating of the spinning capital wall, the contact surface between the heating fluid and the outer wall of the spinning capital should be as large as possible.

Because the spinning dope flows at high speed within the spinning capitary, the temperature of the heating fluid may safely exceed the decomposition temperature of the spinning dope: due to the high speed that the spinning dope flows along the heated wall, The residence time of the spinning dope in the capillary will not be long enough for the spinning dope to reach the wall temperature of the capillary.

Surprisingly enough, even at a wall temperature of about 150 ° C., it has been found that it is possible to spun fibers with a very low tendency to fibrils. The trend of microfibrillation was even lower than in the case of 105 ° C. and the non-looping properties were higher.

Due to the large length of the spinning capital, it is ensured that the spinning-doped layer flowing near the wall is heated. In the case of conventional spinning dope, the viscosity increases as the temperature decreases, so the viscosity of the spinning dope flowing through the spinning capacitor 7 will decrease in the region close to the wall. A more complete velocity profile can be obtained in the core flow over the large moving length of the spinning capital 7 where all of the length is heated.

The formation of the velocity profile along the spinning capital 7 is illustrated schematically in FIG. 2 based on four velocity profiles, A, B, C and D. FIG. Velocity profile A is characterized by being at a short distance behind distributor space 56a and being narrow and maximal in the region of core flow close to centerline M. FIG. The velocity profile A steeply descends towards the wall of the spinning capital 7.

Due to the fact that the spinning capillary wall is heated, the viscosity of the spinning dope decreases in the wall area, the velocity profile gradually becomes uniform and the velocity maximum increases in width. This is shown graphically in velocity profile B.

In the spinning dope outlet opening 94, the velocity distribution in the core flow is nearly constant and steeply descends towards the wall. This is shown in velocity profile C. Steep descent in the wall region is possible due to the low viscosity and strong heating of the spinning capillary wall to the outlet opening 94.

Velocity profile D diagrammatically shows the velocity profile after the spinning dope is discharged from the discharge opening 94. Inert fluid from chamber 72 and spinning dope from discharge opening 94 together form a broad jet.

According to the invention, very long capillary lengths and direct heating of the capacities relative to the capillary diameters interact and result in an advantageous velocity profile. An important aspect in this regard is that the temperature of the spinning capital wall is higher than the core temperature of the spinning dope flow at the center of the spinning capital. The temperature at the core of the spinning dope flow through the capacitor 7 is dependent on the drive temperature of the holding device 60 and the manifold block 6 with the pressure distribution plate 54 and the nozzle body 56 housed therein. Approximately corresponding, the drive temperature is controlled by heating channels 76, 78, 80. When flowing through the spinning capital, the core flow remains unaffected and does not change its temperature.

Due to the small wall thickness of the capillary 7, the temperature of the spinning capillary wall 7 can be adjusted more accurately and quickly in response: due to the small mass of the spinning capillary wall, the wall temperature is increased by the heating chamber 70. It will react immediately to the temperature change at.

In order to intentionally adjust the wall temperature and intentionally influence the flow through the capillaries 7 in this way, a regulator (not shown) can be provided. The regulating device is connected to sensors (not shown), which are the temperature of the capillary wall and / or the temperature of the heating fluid in the heating chamber 70, the flow rate of the spinning dope through the capillaries and the driving of the spinning dope. Detect the pressure. In this way, a closed-loop regulation circuit can be installed and the temperature of the wall can be automatically adapted to the changing driving conditions by this regulation circuit or by regulation from the outside. Can be adapted. Therefore, changes in driving variables can be compensated without any degradation of the spinning quality.

The test results show that when the walls of the spinning capital 7 are heated even in the region of the discharge opening 94, the tendency of microfibrillation can be reduced to a critical extent.

For this purpose, the heating fluid is transferred from the heating chamber 72 through the gap 74 past the outer wall of the spinning capital 7 and from the spinning head 8 in the embodiment according to FIG. 2. This will ensure that the spinning capital is actually heated over its entire length and that a more complete flow profile that develops over the length of the spinning capital 7 cannot weaken due to the colder wall at the end of the travel length. .

Fluid flows from the gap 74 at a high velocity at least corresponding to the rate at which the spinning dope exits the outlet opening 94. The fluid also acts as a transfer fluid that entrains and stabilizes the spinning dope jets.

If the rate of discharge of the fluid is higher than the speed of spinning dope, tensile stress will act on the edge of the spinning dope jet, which will increase the length of the high viscosity jet.

As with the fluid in the heating chamber 70, the fluid in the heating chamber 72 may be part of a closed loop control circuit for the wall temperature of the spinning capital 7. For this purpose, as well as sensors for detecting the temperature of the spinning capital wall and the temperature of the heating fluid, a large number of sensors for detecting the driving variables of the spinning system may be provided, as described above. The signals from these sensors are provided to a thermostat, by which the temperature of the heating fluid in the heating chamber 70 is regulated.

Due to the division into two heating chambers 70, 72, the temperature of the two heating fluids in these chambers is otherwise adjustable. In this regard, it has been found to be advantageous when the spinning capital wall close to the discharge opening 94 is maintained at a temperature higher than the central region of the spinning capital. This method functions to suppress the aforementioned strand expansion.

By dividing the chamber 70 into additional heating chambers that are independent of each other, the temperature profile along the spinning capital is in the direction of flow of the spinning dope according to another embodiment, in particular in cases where the capital is very long. In this way, it can be adjusted more precisely. Each of these chambers is equipped with separate sensors.

Next, the structural design of the second embodiment will be described with reference to FIG.

In doing so, only differences that exist in comparison with the first embodiment will be described. Similar elements having the same function as the elements of the first embodiment or the same elements have the same reference numerals in FIG. 3.

The second embodiment according to FIG. 3 is substantially different with respect to the structural design of the heating chamber 70: The embodiment of FIG. 3 shows the outlet opening 94 of the individual spinning caps 7 in the region of spinning caps. It has only a single heating chamber 70 up to and defining the gap 74. Each spinning capital 7 may have its own heating chamber 70, but a number of spinning capacities 7 may be coupled to one heating chamber 70. Neither the second chamber 72 nor the second housing 68 is provided.

In the embodiment of FIG. 3, the heating chamber 70 surrounds the outer surfaces of the spinning capital and defines an annular or elliptical tube 100 defining an annular space 102 between the spinning capital 7 and the housing 66. ) Is attached. The annular space 102 opens with an annular gap 74.

The heating fluid in the annular space 102 heats the entire outer wall of the spinning capital to the outlet opening 94. Therefore, the heating fluid is the part that acts directly on the spinning capital wall and can be used to intentionally adjust the wall temperature.

Tube 100 is formed from a precision steel tube.

The heating fluid flows from the annular space 102 that is parallel and coaxial to the spinning dope jets discharged from the spinning dope discharge openings. This allows the spinning dope jet to be transferred quietly.

Next, a third embodiment of the spinning head according to the present invention is described with reference to FIG.

In doing so, only differences that exist when compared with the second embodiment will be discussed. Components of the third embodiment that are identical and / or have the same function as the second embodiment are provided in FIG. 4 with the same reference numerals that were used in FIG. 1.

The embodiment of FIG. 4 differs from the second embodiment as long as the gap 74 defined by the housing 66 is elongate rather than annular. The housing 66 may be implemented in one piece or may have two wings 104a and 104b configured to lie perpendicular to the centerline M. The width of the gap 74 can be adjusted by placing the vanes in the direction of the arrow shown in FIG. 4.

Next, a fourth embodiment of the spinning head according to the present invention will be described with reference to FIG.

In doing so, only differences that exist when compared with the second embodiment will be discussed. Components of the fourth embodiment that are identical and / or have the same function as the second embodiment are provided in FIG. 5 with the same reference numerals that were used in FIG. 1.

In the case of the spinning head according to the fourth embodiment, the heating chamber is no longer provided. The spinning capillary is no longer heated via the heating fluid, but is heated via the electrical heating jacket 110 which is part of the heating device of the spinning head.

The heating jacket 110 may be part of a closed loop control circuit for regulating the temperature of the spinning capital wall: This type of closed loop control circuit has been described above.

In order to achieve precise control of the temperature profile along the length of the spinning capital, the heating jacket may be divided into a number of independently driven heating jacket portions.

The spinning method of the present invention makes it possible to produce cellulose fibers with a low tendency to microfibrillation and with improved non-looping properties.

Claims (45)

Cellulose, water and tertiary, characterized in that the walls of the spinning capital 7 are heated at a temperature higher than the core temperature of the spinning dope in the spinning capital at least in the cross-sectional direction near the spinning-doped outlet opening 94. Supplying a spinning dope comprising a mixture of amine oxides to at least one spinning head; And And transmitting the spinning dope to the spinning head through at least one spinning capital, the spinning dope discharge opening through which the spinning dope exits the spinning head, mounted at its downstream end. How to spin a fret. The method of claim 1, wherein the walls of the spinning capillary are heated directly by a heating device (70, 72). Method according to one of the preceding claims, characterized in that the wall temperature of the spinning capital (7) is adjusted to an adjustable value by means of a temperature controller. Spinning dough according to any of the preceding claims, characterized in that the wall temperature of the spinning capital (7) is adjusted in accordance with the mass flow rate of the spinning dope through the spinning capital (7). How to spin a fret. The wall temperature of the spinning capital 7 is according to the spinning pressure in the spinning dope, preferably in the spinning capital 7. Spinning doping, characterized in that it is adjusted according to the spinning pressure of the spinning doping. 6. The predetermined temperature profile according to claim 1, wherein the predetermined temperature profile across the flow cross section of the spinning capital 7 heats the spinning-capital wall when the spinning capital is in operation. 7. Spinning dope, characterized in that it is adjusted by. 7. The method according to any one of claims 1 to 6, wherein the predetermined temperature profile of the spinning capital wall is determined by heating the spinning capital wall by heating the spinning capital wall when the spinning capital is in a driven state. A spinning doping method, characterized in that it is adjusted in the flow direction. 8. The method of claim 1, wherein the spinning-capital wall is heated by a heating fluid flowing around the wall of the spinning capillary on its outside. 9. In the region proximate the spinning dope discharge opening 94, the wall temperature of the spinning capital 7 produced by the heaters 70, 72 is determined by the spinning dope of the spinning dope when the spinning head 8 is driven. At least one spinning capillary having a spinning-doped discharge opening at its downstream end, characterized in that it is higher than the core temperature, wherein the spinning dope is discharged from the spinning head through the spinning dope discharge opening and A spinning head for spinning a spinning dope, consisting of a mixture of cellulose, water, and a tertiary amine oxide, further comprising a temperature-controlled heater acting on the dope, flowing through the spinning head. 10. The area of the spinning capillary wall, heated by the heaters 70, 72, and whose temperature is above the core temperature of the spinning dope, is essentially up to the spinning dope outlet opening 94. Spinning head, characterized in that extending to. The area of the spinning capillary according to claim 9 or 10, wherein the area of the spinning capillary wall heated by the heating devices (70, 72), the temperature of which is higher than the core temperature of the spinning dope, is obtained. Spinning head, characterized in that it extends essentially over the entire length of. 12. The spinning capillary (7) according to any one of claims 9 to 11, wherein the spinning capillary (7) is embodied as a spinning capillary tube in the form of a substantially thin wall tube, and the heating devices (70, 72) are Spinning head, characterized in that it acts directly on the wall area of the spinning capillary tube close to the dope outlet opening (94). 13. A control unit according to any one of claims 9 to 12, wherein a control unit is provided, which acts on the heaters 70, 72, by which the spinning-capital tube The spinning head, characterized in that the temperature of the directly heated wall region of (7) is adjusted at least in the cross-sectional direction. Spinning head according to any one of claims 9 to 13, characterized in that the heating device (70, 72) comprises a heating fluid surrounding at least the cross-section of the spinning-capillary tube (7). . Spinning head according to claim 14, characterized in that the heating fluid of the heating device (70, 72) surrounds the spinning-capillary tube (7) in at least a cross-sectional direction. The spinning-doped discharge opening 94 of the spinning-capillary tube 7 is surrounded by a gap opening 74 in at least a cross-sectional direction. And, when the spinning head is in the driven state, a conveying fluid necessarily flows out of the gap opening (74) in the direction of the spinning dope exiting from the spinning-dope discharge opening (94). 17. The speed of the spinning dope discharged from the spinning-dope discharge opening (94) according to claim 16, wherein the speed of the conveying fluid flowing out of the gap opening (74) when the spinning head is in a driven state. At least substantially corresponding to the spinning head. 18. The method according to any one of claims 9 to 17, near the spinning-dope discharge opening, the spinning-capillary tube 7 is surrounded by a heating chamber 70, 72 containing a heating fluid. Spinning head, characterized in that. 19. Spinning head according to any one of claims 16 to 18, characterized in that the heating chamber (72) communicates with the gap opening (74). 20. The spinning head according to any one of claims 16 to 19, wherein said heating fluid acts as a transfer fluid and is transmitted from said heating chamber (72) through said gap opening (74). 21. The annular space 102 extends between the heating chamber 70 and the gap opening 74, wherein the annular space 102 is the full length of the tube. Spinning head, characterized in that it surrounds the capillary tube (7) from the outside along the. 21. The spinning head of claim 20, wherein said annular space (102) has a substantially elliptical transverse cross section. The spinning head according to any one of claims 9 to 21, characterized in that the length of the spinning capital (7) is 20 to 150 times the diameter of the spinning capital. The spinning head according to claim 23, wherein the length is the length through which the spinning dope flows, and / or the diameter is the inner diameter of the spinning capital. 25. Spinning head according to any one of claims 9 to 24, wherein the discharge transverse cross section (94) is circular. 27. Spinning head according to claim 25, characterized in that the discharge transverse cross section (94) has a diameter of less than 500 mu m, preferably less than 250 mu m. Spinning head according to any of the claims 9 to 26, characterized in that the wall thickness of the spinning capillary tube (7) is less than 200 μm, preferably less than 150 μm. 28. Spinning head according to any one of the preceding claims, characterized in that the temperature of the heating fluid in the heating chamber (70, 72) is at least 100 ° C, preferably about 150 ° C. 28. Spinning head according to any one of claims 9 to 27, wherein the temperature of the heating fluid in the heating chamber (70, 72) is in the range of 50 ° C to 150 ° C. 28. Spinning head according to any one of claims 9 to 27, characterized in that the temperature of the heating fluid in the heating chamber (70, 72) is in the range of 80 ° C to 150 ° C. 28. Spinning head according to any one of claims 9 to 27, wherein the temperature of the heating fluid in the heating chamber (70, 72) is in the range of 100 ° C to 150 ° C. 28. Spinning head according to any one of claims 9 to 27, characterized in that the temperature of the heating fluid in the heating chamber (70, 72) is in the range of 50 ° C to 180 ° C. 33. The method of any one of claims 9 to 32, wherein at least one temperature sensor is provided for detecting the temperature of the capillary wall and / or the temperature of the spinning dope in the region of the capillary wall. The capping wall temperature is configured to be output by the temperature sensor to the control device in the form of an electrical signal. 34. The spinning head of claim 33, wherein said temperature sensor is implemented as an electrical resistance element. 35. A method according to any one of claims 9 to 34, wherein at least one temperature sensor for detecting the temperature of the heating fluid is provided, wherein the temperature of the heating fluid is adjusted in the form of an electrical signal by the temperature sensor. Spinning head, characterized in that configured to be output to the device. 36. The gap according to any one of claims 9 to 35, wherein the gap 74 is defined by a housing (100; 104a, 104b) which is movable laterally in at least the cross-sectional direction with respect to the longitudinal axis of the spinning capillary. Spinning head, characterized in that the flow cross section of the gap (74) is variable. 37. A spinning head according to any one of claims 9 to 36, wherein said spinning capital is surrounded by at least one electric heating element. Spinning head 8 is embodied in accordance with any one of claims 9 to 37 and / or spinning system 1 is characterized in that it is embodied for carrying out the method according to any one of claims 1 to 8. Spinning head or a plurality of spinning heads, from which the spinning dope can be woven to obtain formed bodies, whereby the spinning dope is transferred from the pressure equalization vessel to the spinning head or spinning heads. A spinning system comprising a spinning dope consisting of cellulose, water, and a tertiary amine oxide, and a pressure equalization vessel comprising one or more stabilizers. 39. The spinning system of claim 38, wherein the spinning system comprises an air gap 10 after the spinning head 8 or the spinning heads 8, wherein the spinning dope opens the spinning-doped outlet opening 94. Spinning system, characterized in that it is drawn by flowing into the air gap (10) after leaving. 40. The spinning system (1) according to claim 38 or 39, wherein the spinning system (1) comprises a settling tank (11) downstream of the air gap (10), wherein the spinning dope discharged from the spinning head (8) Spinning system, characterized in that it is immersed in the settling tank after passing through the gap (10) and drawn to obtain the formed body. 41. The drawing-off device 12 according to any one of claims 38 to 40, thereby providing a drawing-off device 12 in which the spinning dope can be drawn from the settling bath in the form of a settled thread or formed body. Spinning system characterized in that. A product produced according to the method according to any one of claims 1 to 8, wherein the final product is a filament. A product produced according to the method according to any one of claims 1 to 8, wherein the final product is staple fiber. A product produced according to the method according to any one of claims 1 to 8, wherein the final product is spunbonded fibers. A product produced according to the method according to claim 1, wherein the final product is a film / sheet.