JP2648154B2 - Air gap spinning method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Application Field of the Invention] The present invention relates to a so-called loose gap in which a spinning dope (hereinafter, abbreviated as dope) is once discharged into the air from a spinneret and then guided into a coagulating liquid to spin. More specifically, the wet spinning method is suitable for high-speed spinning, the spinning state is stable,
The present invention also relates to an air gap spinning that is easy to spin.

[Conventional technology]

The so-called air gap type wet spinning method (or so-called air gap type) in which the dope is once discharged from the spinneret into the air or into an inert non-coagulating atmosphere and then guided into a coagulation bath to solidify the dope stream.
Dry jet wet spinning method, semi-dry semi-wet spinning method, dry-wet spinning method, etc.) is a method in which the discharged dope flow is stretched in a non-coagulated air layer so that the dope flow is thinned, that is, the fine denier is reduced. It is easy to make it easy to take out, it is easy to take off at high speed, and because the spinneret is not immersed in the coagulating liquid,
It has the advantage of being able to set the temperature independently of each other, and has been proposed as one of the conventional wet spinning methods (for example,
No. 31-8313, Japanese Patent Publication No. 36-12711, Japanese Patent Publication No. 40-2
No. 6212, Japanese Patent Publication No. 42-815, etc.).

Furthermore, in order to further enhance the high-speed take-up of the air gap wet spinning (hereinafter simply referred to as the air gap spinning), that is, the high-speed spinnability, the coagulated yarn is taken out of the spinning bath through a flow tube provided in the spinning bath together with the coagulating liquid. The combination with the so-called loose-flow-type wet spinning is also available in Japanese Patent Publication No. 45-2765 and Japanese Patent Publication No. 55-55.
It is proposed in, for example, Japanese Patent Publication No. 14170.

This combination of air gap spinning and flow tube wet spinning left spinning baths such as aramid or other liquid crystal doped spins with a linear molecular structure, such as polyparaphenylene terephthalamide, or copper ammonia rayon or viscose rayon. Many drawbacks have been proposed in cases where the subsequent drawing rate is low, and therefore the take-up speed from the spinning bath itself must be increased, and further reduces the running frictional resistance between the coagulating liquid and the coagulated yarn,
Many proposals have been made to avoid damage to the coagulated yarn. For these, for example, JP-A-53-78230,
JP-A-53-78231, JP-A-56-128812, JP-A-57-121612, JP-A-59-157316, JP-A-61-102413, JP-A-61-102413 It is disclosed in JP-A-239012 and the like.

[Problems to be solved by the invention]

The above-described air gap spinning method is preferable in terms of speeding up and the like, but the biggest problem is that the dope of the air layer having substantially no coagulation ability is discharged from the spinneret, so that the spinneret of the dope is used. The dope sticking to the surface of the spinneret is not limited to cutting the thread only at the sticky part, and the dope flow discharged from the adjacent spinning hole is also adhered to the surface of the spinneret. The problem that spinning is impossible over the entire surface of the die is likely to occur. Similarly, a dry spinning method or a melt spinning method for discharging a dope or a molten polymer into a gas has the same problem. Neither of these problems is a difficult ratio in the air gap spinning method in that the dope is dried in a gas or the molten polymer is cooled and solidified.

Furthermore, a problem with the air gap spinning method is that the dope stream discharged into the air layer must then break through the surface of the coagulating liquid and be guided into the coagulating liquid. In this case, at the time of thread stand,
At the time of yarn breakage, dope flow is caused by interfacial tension with the coagulating liquid surface.
Often, the liquid surface drifts without sinking in the liquid, complicating the thread stand operation.In particular, when cutting a single yarn generated during spinning, the cut dope flow drifts on the liquid surface, It cuts to other yarns by contacting with other yarns or closes the inlet of the flow tube with drifting yarns.

All of these require a lot of manpower and time to start spinning in the industrial implementation of air gap spinning, and also have a large problem in raising the operation degree such as interruption of spinning.

[Means to solve the problem]

The above problem is that in the air gap spinning, the coagulated yarn is drawn out of the spinning bath together with the coagulating liquid through a flow tube,
The inlet of the flow tube is positioned at a distance of 5 mm to 40 mm from the surface of the coagulating liquid, and the spinning axis of the spinneret is on the center line of the flow tube, and the distance (L ₀ ) from the surface of the coagulating liquid to the inlet of the flow tube an intermediate point of the discharge of more than 350 meters / minute using those as perforated intersect at one point, a further spinning dope from該紡hole between a point away from the flow tube inlet only flow tube exit direction L ₀ The problem is solved by discharging at a linear velocity.

Hereinafter, the configuration of the present invention will be described in detail with reference to the drawings showing an example of the embodiment.

FIG. 1 shows an example of an embodiment of the present invention,
The dope is supplied to the spin pack 2 via the dope supply pipe 1, and is discharged through the spinneret 3. After the dope flow discharged from the spinning hole 4 passes through the air layer 8, it enters a coagulating liquid surface (hereinafter simply referred to as a liquid surface) 9, and travels as a yarn 7 while coagulating in the coagulating liquid 10. The yarn is drawn out as a yarn 14 through the flow tube 11 and sent to a finishing device (not shown) via a deflection guide 15. The coagulation liquid is sent from the nozzle 13 to the spinning bath 12 having a closed structure, and in this example, the entire amount thereof flows out together with the yarn through the flow tube 11.

The most characteristic feature of the air gap spinning of the present invention is that, as the spinneret 3, the spinning shaft 5 of the spinning hole 4 is inclined and bored so as to intersect at one point 6 on the center line of the flow tube 11, Furthermore, dope is produced from the spinner designed as such.
The discharge is performed at an extremely high discharge linear velocity of 350 m / min or more. Due to the combination of these, the separation of the dope from the spinneret surface, which is a problem of the present invention, is difficult. The difficulty of breaking through the interface when the flow enters can be solved.

That is, when the discharge linear velocity is less than 350 m / min, the discharged dope is likely to adhere to the surface of the spinneret and should be avoided. When it collides with the solidification liquid surface 9
Overcoming the interfacial tension, the dope flow does not automatically enter the coagulating liquid 10. Therefore, the effect of the present invention becomes more remarkable as the discharge linear velocity increases, but it may be approximately 350 m / min or more, more preferably 450 m / min or more. The upper limit of the discharge linear velocity is not particularly limited, and may be arbitrarily selected from the desired denier, take-up speed, and the like as long as stable dope discharge is maintained.

In addition, it is important to discharge the dope from the spinning group designed so that the spinning shaft 5 which is a feature of the present invention intersects at a specific point 6 on the center line of the flow tube under the above conditions. The dope discharged at a high discharge linear speed from the spinning hole 4 of the slightly inclined spinning shaft 5 forms a dope flow along the spinning shaft 5 and travels in the air, and tilts toward the coagulation liquid surface. Collision at an angle
Promotes breakthrough of the dope flow. Further, the dope flow that has entered the coagulation liquid automatically reaches the inlet of the flow tube without diffusing in the liquid, and flows out together with the coagulation liquid in the flow tube.

The position of the intersection 6 of the spinning shaft 5 is of course also a weight,
Is closer to the liquid level 9 than the midpoint between the
At the time of the yarn standing, the dope streams are easily merged into one, and even if a drawing force is applied, the dope flows are converged due to the interfacial tension of the liquid surface 9 and a problem that the dope flows cannot be easily separated occurs, which is not preferable. Further, the intersection 6 can not obtain the effect of the present invention becomes similar to that using the conventional spinneret If too further from the liquid surface 9, generally, contains only L ₀ toward the flow tube inlet flow tube outlet Should stop within that point.

It should be understood that the intersection 6 may not actually intersect at one point from the point of machining accuracy in practice, and it is generally 10% of the distance L ₀ between the spinneret surface and the inlet of the flow tube. Within this range or within 2-3 mm, the goal of the present invention is achieved.

As shown in FIG. 1, a preferred example of the spinneret used in the practice of the present invention is a spinneret having a concave surface and a spinning hole formed substantially perpendicular to the concave surface. In such a case, the dope stream is discharged almost perpendicularly to the spinneret surface, giving a more preferable embodiment in that the occurrence of sticking to the spinneret surface hardly occurs.
However, it should be understood that the spinning axis may not be completely perpendicular to the spinneret surface due to circumstances such as machining accuracy.
The objective is achieved if the error is within approximately 10 °, preferably within 5 °.

It has not been fully elucidated what principle the effect of the spinning group having the above-mentioned inclined spinning axis which is a feature of the present invention is based on. It is supposed that the collision of the dope flow with the liquid surface weakens the effect of the interfacial tension. Also, in terms of phenomena, each dope stream is inclined to the liquid surface, which also collides in the direction of converging at the center of the flow tube, so that the dope flow that can not break through the liquid surface and drifts on the liquid surface Even when generated, the drift direction is directed to the center of the dope flow group, and the kinetic energy of the large dope flow remains at the drift speed, and the dope flow drifting converges to one point, and the flows merge. May break through the liquid surface. Similarly, when a partial yarn break occurs due to an accident during spinning, even if the dope stream drifts without being able to break through the liquid surface, the drifting dope is not cut by another running dope. It flows rapidly in the direction of flow, instantaneously merges with the running dope flow, breaks through the liquid surface, and is then guided into the liquid.

Incidentally, when the dope flow runs while solidifying in the coagulating liquid 10 and is taken up as the coagulated yarn 14 through the flow tube 11, the dope flow traveling in the air layer 8 is no longer in the spinning axis direction, On the same line as the yarn 7 running in the coagulating liquid,
It often runs straight from the spinning hole toward the flow tube.

In practicing the present invention, the size and shape of the spinning are not limited, but the diameter of the spinning is preferably at least 0.04 mm or more, and below that, hole clogging is likely to occur due to high-speed dope discharge, Also, there are many problems in drilling accuracy due to poor drilling accuracy. On the other hand, if the spinning diameter is too large, the dope discharge amount per hole is too large, and there is a limit in high-speed take-up corresponding to a high discharge linear speed, so the denier per single yarn becomes excessive, and the limit naturally occurs. is there. Usually, it is often selected to be about 0.20 mm or less, more preferably about 0.10 mm or less.

Naturally, the spinneret used in the present invention only needs to consider the strength setting that can withstand the back pressure due to the above-mentioned discharge linear velocity, and other materials and shapes are not limited at all. The shape of the spinning hole is not particularly limited, and may be a shape other than a circle for spinning a so-called irregularly shaped yarn.

In practicing the present invention, and the number of紡孔forming the紡孔group that can be applied, as the shape and size of the group, the inflow of L ₀ and, diameter and shape of the flow tube, into a coagulating liquid flow pipe It depends on the speed and the like, and is not particularly limited. However, if the area of the spinning group is too large, the crossing angle of the spinning axis becomes too large, which causes a problem in the processing surface of the spinneret. the diameter of紡孔sequence circle, three times the distance L ₀ from the spinneret surface to the flow tube inlet less, preferably 2 times the L ₀ or less, more preferably L ₀ or less, as the number of holes 1000
The number of holes is selected to be not more than 150 holes. As a special case, the effect of the present invention can be exerted even when the flow tube is formed into a slit shape and the arrangement of the spinning groups is arranged in a straight line of several rows to form a rectangle, or even with a larger number of spinning holes.

In carrying out the air gap spinning using the flow tube of the present invention, it is necessary to appropriately determine the distance (L ₀ ) between the coagulating liquid surface 9 and the inlet of the flow tube 11.

When L ₀ is large, the time of yarn cutting that occurs during the spinning start or spinning, the yarn is continued flow tube inlet is introduced into the bath by breaking through the automatic liquid level as described above Shirubebi No coagulation liquid
Easy to stay in part 10 At the same time, when L ₀ is large, the contact between the traveling yarn 7 and the coagulating liquid 10 becomes longer, the frictional resistance increases, and problems such as cutting of the yarn occur. Thus L ₀ is about 40mm or less, more preferably 30mm or less, a particular case is set to 15mm or less.

On the other hand, if L ₀ is 5 mm or less, vortices are likely to be generated on the surface of the coagulating liquid, and the liquid level cannot be maintained stably, which is not preferable.

The inlet of the flow tube is preferably located directly on the spinneret surface and on a vertical line from the center of the spinneret to the spinneret surface. The effects of the present invention can be expected.

The term “flow tube” as used in the present invention is a general term for a thin tube for taking out a thread that is coagulating from a coagulation bath together with a coagulating liquid, and has no restrictions on its inner diameter, length, shape, and the like. Instead, an optimum one may be arbitrarily selected depending on the polymer to be used, the properties of the dope, the coagulation mechanism, and the like. In an extreme case, an orifice formed in a coagulation bath may be used.

As a special type of the flow tube, as described above, the spinning group may be arranged in a rectangular shape, and the flow tube may be used in a slit shape.

In carrying out the present invention, the thread-like take-up speed from the flow tube and the speed of the coagulating liquid flowing through the flow tube are not particularly limited, but in order to take advantage of the high discharge linear speed and stable spinnability of the present invention. High take-off speed is preferred, at least 20
High-speed take-up such as 0 m / min or more, and in some cases, 2000 m / min is also possible. Also, when pulling the yarn from the flow tube at such a high speed, if the speed difference between the coagulated yarn and the coagulating liquid in the flow tube is excessive, unnecessary deformation of the yarn may occur due to frictional force. This is not preferable because it causes fiber cutting and deterioration of physical properties.
Usually, this speed difference is preferably set to 200 m / min or less, more preferably 100 m / min or less.

The length of the air layer is not limited in practicing the present invention, but if it is too large, the dope flow traveling in the air layer becomes unstable and loses the liquid level breaking effect characteristic of the present invention. 30mm or less, preferably 20mm
mm or less.

In carrying out the flow tube wet spinning of the present invention, the composition of the spinning dope is not limited, and it is sufficient that the conditions required for the present invention can be implemented industrially. Because of the linear discharge speed which can be said to be abnormal from the conventional spinning concept, the back pressure of the spinneret becomes extremely high, so that the viscous resistance decreases drastically under high shearing speed. Also, a solution of a polymer referred to as a rigid linear polymer or a worm (insect) -like polymer which is easily flow-oriented is preferable.

Further, for the same reason, the apparent viscosity under the shear rate at the time of passing through the spinning is desirably low, preferably 200 poise or less, but even if it is higher, the spinning equipment has sufficient mechanical strength. The implementation of the present invention is possible if designed.

Examples of suitable dopes for practicing these inventions include:
Optically anisotropic dope prepared by dissolving polyparaphenylene terephthalamide (hereinafter abbreviated as PPTA) in concentrated sulfuric acid.
No. 8474, JP-B-59-14568) and optically anisotropic doping of cellulose derivatives (JP-A-52-96230).

Further, although not an optically anisotropic dope, a dope in which cellulose is dissolved in a copper ammonia complex solution, a dope in a mixture of N-methylmorpholine oxide (hereinafter abbreviated as NMMO) and water, and a dope with an aqueous solution of cellulose xanthate in alkali ( So-called viscose dope) is also suitable for the practice of the present invention, among which viscose dope has a low viscosity,
Discharge can be performed stably up to an extremely high discharge linear velocity, for example, 1000 m / min or more. In addition, NMMO and water dope can be used at elevated temperatures up to around 100 ° C., which is advantageous in that the viscosity at the time of discharge can be reduced.

The flow tube wet-spun yarn according to the method of the present invention is then guided to an optional finishing step according to the properties of each polymer and the yarn and the drawing speed to be completed as a fiber.

For example, a coagulated yarn obtained from an optically anisotropic dope such as PPTA has already been completed in a fiber structure as it is spun, and therefore, Japanese Patent Publication No. 55-9908, which has already been proposed by the present inventors. As described above, a method of depositing on a conveyor, washing with water, refueling, and drying can be applied. Further, when the present invention is applied to viscose rayon, it may be refined after being once wound up in a cake shape by a conventional centrifugal method, and by taking advantage of the stable spinnability of the present invention, a Nelson roll method. It is also preferable that the finishing treatment is performed by another continuous refining-drying device.

[Function of the invention]

The feature of the air gap spinning of the present invention is that it is suitable for high-speed spinning in combination with the flow tube spinning method, and the most characteristic feature is that the spinning axis of the spinning nozzle is a flow tube. And the distance from the coagulation bath surface to the inlet of the flow tube intersects at a point between the midpoint of (L ₀ ) and the point separated from the inlet of the flow tube by L _{0 in the} direction of the outlet of the flow tube. The dope discharged as described above is used, and the dope is discharged at a high speed of 350 m / min or more. And the problem of dope sticking to the spinneret, which has been a problem in the conventional air gap spinning, does not occur. Furthermore, the dope stream is jetted out along the spinning axis and immediately enters the coagulation liquid immediately without drifting to the coagulation liquid surface because it collides with the coagulating liquid surface at a large angle at an inclined angle. Above all, it reaches the flow tube in a focused state without diffusion.

The inlet of the flow tube is appropriately set as described above, and the yarn automatically flows out with the coagulating liquid through the flow tube.

In this way, the spinning can be started automatically and smoothly, and even for the cutting of the dope stream that is accidentally generated during spinning,
Since the spinning is automatically restored, the low operating rate, which has been a problem of the air gap spinning, can be solved.

〔Example〕

Hereinafter, examples of embodiments of the present invention will be described by way of examples. In the examples, percentages are by weight unless otherwise specified.

Example 1 A PPTA polymer was obtained by a low-temperature solution polymerization method under the following conditions.

In a polymerization apparatus disclosed in JP-B-53-43986, N-
70 parts of anhydrous calcium chloride was dissolved in 1000 parts of methylpyrrolidone, and then 48.6 parts of paraphenylenediamine were dissolved. After cooling to 8 ° C, terephthalic acid dichloride 91.4
Parts were added at once in powder form. After a few minutes, the polymerization reaction product was solidified into a cheese, and the polymerization reaction product was discharged from the polymerization apparatus in accordance with the method described in JP-B-53-43986. The polymerization reaction product was pulverized. Next, the finely pulverized product was transferred into a Henschel mixer, added with an approximately equal amount of water, further pulverized, filtered, washed several times in warm water, and dried in hot air at 110 ° C. 95 parts of a pale yellow PPTA polymer having a η inh of 6.2 measured at 30 ° C at a concentration of 0.2 g / 100 ml in 98.5% sulfuric acid was obtained.

99.8% concentrated sulfuric acid polymer concentration obtained PPTA polymer
The solution was dissolved at 70 ° C. for 2 hours so that the concentration became 19%. The dissolution was carried out in a vacuum, and after the dissolution, the mixture was allowed to stand under vacuum for 2 hours to remove bubbles, thereby adjusting the optically anisotropic dope. The optical anisotropy was confirmed by making the dark field under crossed Nicols of a polarizing microscope a bright field with a dope preparation.

This dope is 5μ of sintered SUS316 stainless steel non-woven fabric.
After filtering through a filter that guarantees exclusion up to m, it is made of tantalum, and the spinneret surface is processed into a concave surface so that the peripheral part has a slope of 162 ° as shown in FIG.
Twenty-five 0.045 mm diameter spinning holes are drilled on the circumference of 8 mm, and the spinning axis is perpendicular to the surface of the spinneret,
The spinning axis was discharged to the air layer at a discharge linear speed of 400 m / min at a speed of 15 mm through a spinneret intersecting at a point 25 mm from the spinneret.

As a spinning bath, as shown in FIG.
A pressure reducing chamber 16 is provided at the outlet of the flow tube 11 described in
The chamber is suctioned to a reduced pressure through a, and the coagulating liquid remaining in the chamber is suctioned and discharged by a nozzle 17b, and an orifice 18 provided at the lower part of the chamber is sucked and discharged.
A device for pulling out the yarn through the device was used.

Here, in the coagulation liquid surface and the flow tube inlet of the distance L ₀ is 15 mm, as the coagulating solution with 20% concentrated sulfuric acid 30 ° C..

The flow tube 11 is obtained by squeezing one end of a glass tube having a diameter of 15 mm into a conical shape, and piercing an orifice having a diameter of about 1 mm and a length of about 1 mm at its tip so that the orifice portion is inserted into the spinning bath. installed.

The pressure in the decompression chamber 16 was reduced, and the linear velocity of the orifice portion of the coagulating liquid flowing from the orifice into the decompression chamber was adjusted to 950 m / min, and spinning was started.

Simultaneously with the start of spinning, a dope flow is spouted from the spinning vigorously and travels through the air layer so as to form a cone along the spinning axis. The stand was completed automatically.

Next, the coagulated yarn was drawn out from the decompression chamber 16 through the lower orifice 18 at a speed of 1000 m / min.

As described in JP-B-55-9088, the drawn coagulated yarn is piled up on a conveyor consisting of an endless belt of a flat woven wire mesh made of stainless steel wire, and is then piled up with a 1% aqueous sodium hydroxide solution. After being neutralized and then washed with water and refueled, it was dried, taken up on a conveyor, and wound up.

The obtained PPTA fiber has a yarn denier of 85 denier,
The strength was 23.7 g / d, the elongation was 5.2%, and the initial modulus was 375 g / d.

During the last about 30 minutes after the start of the spinning, air was mixed into the discharged dope stream, which was considered to be due to poor replacement of the dope in the spin pack. In each case, the dope flow automatically broke through the liquid surface, passed through the flow tube and the lower orifice together with other yarns, and did not result in a failure in which spinning was interrupted.

Comparative Example 1 Spinning was performed under the same conditions as in Example 1 except that the spinneret was changed to a conventional spinneret having a flat spinneret surface and a spinning axis perforated perpendicular to the spinneret surface and parallel to each other. Was.

First, at the start of spinning, the dope flow partially broke through the liquid surface, but most of it drifted off the liquid surface, and was then drawn into the flow tube along with some of the broken yarn, so it drifted at the inlet of the flow tube. The lump that had been clogged was clogged, and the thread could not be threaded.

Next, all the yarns were manually passed through a flow tube, passed through a lower orifice, guided to a net conveyor, and wound up.

As in Example 1, after the start of spinning, air was mixed in the dope stream, and single yarn was cut. As a result, the dope flow of the single yarn cut portion drifted on the liquid surface, and was subsequently caught by another yarn. A phenomenon leading to the flow tube was observed. The entangled yarn became clumped and blocked the flow tube, so that spinning could not be continued.

Example 2 Softwood pulp for dissolution used for rayon was immersed in dilute sulfuric acid and hydrolyzed, and cellulose having an average degree of polymerization of 330 calculated from ηinh by a copper-ammonia solution was reacted with acrylonitrile using sodium hydroxide as a catalyst. The degree of substitution was induced to 2.62 cyanoethylcellulose (CyEC).

Nitrite was removed by urea in advance of this CyEC.
An optically anisotropic dope obtained by dissolving in 30% nitric acid at 0 ° C. to give a concentration of 30% was spun using the apparatus shown in FIG.

The spinneret is made of stainless steel, and the diameter of the spinning array circle is 9 mm and 5 mm.
A hole having 0 holes was used, and a flat spinneret was perforated so that its spinning axis intersected at a point 25 mm from the surface of the spinneret, and discharge was performed at a discharge linear velocity of 350 m / min.
5 ° C. water was used as the coagulating liquid, the air layer was 10 mm, and the distance between the liquid surface and the flow tube was 25 mm. As the flow tube, a glass tube having an inner diameter of 1 mm cut into 50 mm was used, and the evacuation of the decompression chamber was adjusted so that the coagulating liquid flowed out at 775 m / min.

At both the start of the spinning and the breakage of the yarn, it was confirmed that the production of the liquid was extremely easy as in Example 1 and that the yarn was drawn out due to the dope flowing into the flow tube.

The drawn fiber is wound on a stainless steel bobbin, washed by immersing the bobbin in running water overnight, and then dried in an air oven to obtain 6.0 g / d strength, 5.1% elongation C.
yEC fiber was obtained.

Comparative Example 2 A spinneret having the same design as in Example 2 was used except that the normal spinning axis was parallel, and spinning was performed under the same conditions as in Example 2.

In this comparative example, the discharged dope drifted to the surface of the coagulating liquid, was not easily introduced into the liquid, and caused an operational problem that it took time to start spinning.

Example 3 and Comparative Example 3 Ordinary viscose (sodium hydroxide 6%, cellulose 8.5%, γ value 40, viscosity 50 seconds) was added to a coagulation liquid containing sulfuric acid 120g / sodium sulfate 260g / zinc sulfate 15g /. Was spun.

In this embodiment, the spinning bath shown in FIG. 1 is used. As the spinneret, a hole having a diameter of 0.05 mm is formed on the concave surface of the concave spinneret forming a substantially spherical surface by 20 mm from the axis of the spinneret.
Were made of gold-platinum-containing gold perforated so as to intersect at point 3, the air layer was set to 5 mm, and the distance between the liquid surface and the flow tube was set to 8 mm.

The flow tube is a glass tube with an inner diameter of 1.5 mm cut into 40 mm and used.
The coagulation liquid was supplied at a speed of 600 m / min so as to pass through the flow tube.

When viscose was discharged at a discharge linear speed of 800 m / min,
It broke through the liquid surface without any problems and flowed out of the flow tube automatically.

The yarn was drawn out of the spinning bath at 600 m / min, dropped in the space together with the coagulating liquid, then guided to a take-up roll via a guide, deposited on a net conveyor, refined, washed with water, dried and wound up. In addition, the elongation of about 40% occurred between the take-off rolls after leaving the flow tube, and the take-up rolls could take off at 850 m / min.

The obtained fiber is 75 denier, strength 1.71 g / d, elongation 21.
It was 7%, and showed physical properties comparable to cake yarn, despite being spun at several times the speed of ordinary viscose rayon.

On the other hand, for comparison, when the spinning speed was reduced to 200 m / min and spinning was started, the spouted viscose flow accumulated on the liquid surface and blocked the inlet of the flow tube, making spinning impossible. Since the coagulated fiber of the dope was weak, it was impossible to manually thread the fiber into the flow tube, and spinning was abandoned.

〔The invention's effect〕

According to the present invention, wet spinning combining air gap spinning and flow tube spinning suitable for high-speed spinning can start spinning very easily, and automatically even when a single yarn break occurs due to an accident during spinning. This is advantageous in that the spinning is stably continued while the spinning is connected, and the productivity of wet spinning is increased.

[Brief description of the drawings]

1 and 2 are longitudinal sectional views showing an example of an apparatus for performing the method of the present invention. 2 ... Spin pack, 3 ... Spinner, 7 ... Coagulated yarn, 8 ... Air layer, 9 ... Coagulated liquid surface, 10 ... Coagulated liquid, 11 ... Flow tube, 12 ... Spinning bath, 14 ... coagulated thread, 16 ... decompression chamber, 18 ... lower orifice.

Claims (5)

(57) [Claims] In an air gap spinning method in which a spinning dope is once extruded into the air from a spinneret and then the dope stream is introduced into a coagulating liquid and spun, the coagulated yarn is passed from a spinning bath together with the coagulating liquid through a flow tube. Withdrawing, the inlet of the flow tube is positioned at a distance of 5 mm to 40 mm from the surface of the coagulating liquid, and the spinning axis of the spinneret is on the center line of the flow tube, and the distance from the surface of the coagulating liquid to the inlet of the flow tube (L ₀ ) from the midpoint and from the inlet of the flow tube
I used those as perforated intersect at a point between the point separated only flow tube exit direction L _0, and characterized in that for discharging further spinning dope at 350 meters / minute or more discharge linear velocity from該紡hole Air gap spinning method. 2. The air gap spinning method according to claim 1, wherein the spinneret surface is concave, and the spinneret is formed by using a spinneret perforated substantially perpendicular to the spinneret surface. 3. The spin dope is an optically anisotropic dope of polyparaphenylene terephthalamide.
Item 3. The air gap spinning method according to item 2 or 2. 4. The air gap spinning method according to claim 1, wherein the spinning dope is an optically anisotropic dope of a cellulose derivative. 5. The dope according to claim 1, wherein the spinning dope is selected from the group consisting of an alkali aqueous solution dope of cellulose xanthate, a copper ammonia complex solution dope of cellulose, and a mixture dope of N-methylmorpholine oxide and water of cellulose. 3. The air gap spinning method according to claim 2.