JPH07278941A - Wet spinning method - Google Patents

Abstract

PURPOSE:To enable tension applied to yarn in a spinning process to arbitrarily control, reduce spinning tension, prevent yarn from being taken in solidifying liquid stream and subjecting a high polymer solution to wet spinning at a high speed. CONSTITUTION:In a flow bath spinning method having a flow pipe just after spinning and reducing resistance to liquid by moving a solidified liquid in the same direction to advancing direction of yarn, this wet type spinning method is carried out by carrying yarn on a net formed at the top of the flow pipe, removing the solidified liquid on the net while more rapidly traveling a speed of the net than that of the solidified liquid flow and detaching the yarn on the net at a speed faster than that of the net.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for wet spinning a polymer solution.

[0002]

2. Description of the Related Art In a wet spinning method, there is a flow bath spinning method in which the coagulating liquid is made to flow in the same direction as the running direction of the yarn to reduce the relative velocity of the yarn and the coagulating liquid to reduce the resistance of the coagulating liquid. Many have been proposed. For example, Japanese Patent Publication No. 45-25336
In the flow-bath type high-speed spinning method disclosed in the publication, an apparatus composed of a spinneret and a spinning flow tube is proposed, and the coagulating liquid velocity in the straight portion of the flow tube is made close to the spinning velocity to reduce the liquid resistance.

Further, in Japanese Patent Laid-Open No. 60-52610, in a flow bath spinning method, a slight defect is provided at the outlet of a flow tube so that air is sucked and mixed into a coagulation bath to discharge the flow tube. A method is proposed in which bubbles are mixed in the coagulation bath immediately after the flow to relax the momentum of the flow bath and prevent the yarn and the single yarn at the outlet of the flow tube from being taken by the coagulation bath.

[0004]

Even in the conventional wet spinning method, the spinning tension can be somewhat reduced by the techniques disclosed in the above-mentioned Japanese Patent Publication No. Sho and Japanese Patent Laid-Open No. Sho, and a viscose rayon filament is spun at high speed. It was effective for such things. However, when the Young's modulus of the yarn in the coagulation process is low, such as when the polymer solution is an aqueous solution of caustic soda containing alkali-soluble cellulose, the coagulation liquid velocity at the outlet of the flow tube in the prior art is high, and therefore the coagulation liquid flow is high. When the yarn is taken out from the fiber, the yarn is pulled by the coagulating liquid flow (Fig. 2
(See a, b, c), stable spinning at high speed was difficult.

An object of the present invention is to provide a method for stably controlling high-speed spinning by arbitrarily controlling the tension applied to the yarn in the wet spinning process.

[0006]

The inventors of the present invention installed a net running at a surface speed almost the same as the average speed of the coagulating liquid in the flow tube immediately after the conventional flow bath spinning apparatus, and set the tip of the flow tube. The inventors have found that the above problems can be solved by receiving the yarns from the net with the net, and reached the present invention. That is, the present invention uses a spinning flow tube to flow a coagulating liquid flow,
A flow bath spinning method of spinning a discharged polymer solution as a yarn, wherein the yarn is placed on a net running in the same direction as the coagulating liquid flow together with the coagulating liquid flow flowing out from the spinning flow tube,
A wet spinning method, characterized in that the running speed of the net is made to run at a surface speed not lower than the speed of the coagulating liquid flow, and then the yarn on the net is detached from the net at a speed not lower than the running speed of the net; And in the flow bath spinning device,
A wet spinning apparatus, characterized in that a net portion that travels in the same direction as the coagulating liquid flow that receives the coagulating liquid flow and the yarn is provided immediately after the spinning flow tube part, and then a yarn releasing part is provided. .

The present invention will be described in detail below. The polymer solution used in the wet spinning method of the present invention is not particularly limited.
Any material that can be wet-spun can be used. It is particularly effective when Young's modulus and elongation in the solidification process are low, which has been difficult to spin by the conventional flow bath spinning method and the like. For example, a caustic soda aqueous solution of alkali-soluble cellulose is preferably used.

[0008] Alkali-soluble cellulose means cellulose obtained by subjecting natural cellulose such as wood pulp to an explosion treatment and solubilizing it in a 7-10 wt% caustic soda aqueous solution. The wet spinning method of the present invention is a spinning bath spinning apparatus using a polymer solution discharge part and a spinning flow tube part for flowing a coagulating liquid in a polymer solution discharge direction to form a yarn from the discharged polymer solution. A wet spinning apparatus characterized in that a net part that runs in the same direction as the coagulating liquid flow and receives the coagulating liquid flow and the yarn is provided immediately after the pipe part, and then a desorption part that draws the yarn from the net is provided. The biggest feature is that it uses.

First, the wet spinning method of the present invention will be described with reference to the wet spinning apparatus shown in FIG. In the wet spinning method of the present invention, the polymer solution is discharged from the polymer solution supply pipe 1 into the coagulating liquid in the flow tube holder 3 through the spinneret 5. The coagulation liquid is forcibly and quantitatively introduced into the flow tube holder from the coagulation liquid supply pipe 4 by a pump or head pressure.

The yarn 6 and the coagulating liquid pass through the flow pipe 7 and are shaken off on the net 8. The average velocity of the coagulating liquid in the flow tube 7 must be set to be equal to or lower than the surface velocity of the net 8.
The coagulating liquid is, for example, 20% by weight of sulfuric acid at a temperature of -7 if the polymer solution is an aqueous solution of caustic soda containing alkali-soluble cellulose.
A coagulating liquid at ℃ is preferably used. The yarn speed in the flow tube is
Since the average speed of the coagulating liquid in the flow tube is equal to the average speed of the coagulating liquid in the flow tube, if the average speed of the coagulating liquid in the flow tube is set higher than the surface speed of the net, no tension is applied to the yarn, and the obtained yarn has low strength. Therefore, it is not preferable.

When the average speed of the coagulating liquid is slower than the net surface speed, the speed of the yarn spun on the net surface becomes equal to the net surface speed, so that the net pulls the yarn and the inside of the flow tube This causes liquid resistance and tension on the yarn. That is, the tension can be arbitrarily controlled by changing the difference between the net surface speed and the average speed of the coagulating liquid. The difference between the net surface velocity and the average velocity of the coagulating liquid in the flow tube (hereinafter abbreviated as ΔV, ΔV = net surface velocity-average velocity of the average velocity of the coagulating liquid in the flow tube) is the polymer solution used, etc. Depends on

For example, when the polymer solution is a caustic soda aqueous solution of alkali-soluble cellulose, ΔV is 0 m / min.
It is preferably above 36 m / min. △ V is 0m / mi
When it is less than n, not only is the yarn slack on the surface of the net, spinning stability is low, but also the yarn is not subjected to any tension at all, and the strength of the obtained yarn is low.

When ΔV is 36 m / min or more, the yarn is excessively tensioned and the spinning stability is deteriorated. When ΔV is increased, the yarn is cut. If the ΔV is the same, the tension applied to the yarn is the same regardless of the speed. Therefore, to increase the spinning speed, increase the net surface speed and the coagulating liquid speed to the specified speeds while maintaining ΔV at 0 to 35 m / min. Good. More preferable ΔV is 10 m / min to 30 m / min.

In the conventional viscose rayon filament production technology, there are many processes using a net, but in that case, the net surface speed is 1/100 or less of the yarn speed in the spinning section, and the surplus is excessive. Fold the yarn from which the coagulation liquid has already been removed onto the net and wash it with water.
It is only used to allow a sufficient residence time for drying. That is, the net in this case has no effect of reducing the spinning tension applied to the yarn in the spinning section, and is only used for the post-treatment.

Of the yarn and the coagulation liquid which have been shaken off on the net, the coagulation liquid falls under the net and is removed and separated from the yarn. Since the yarn is supported by the net,
No yarn is taken in the coagulating liquid flow as in the prior art shown in b and c. It is effective to remove and separate the coagulation liquid not only by gravity but also by forcefully removing it with the suction 9. It is still more effective if the free roll 10 is provided side by side to forcibly remove the coagulating liquid. Suction and free rolls are more effective at higher spinning speeds.

The yarn 6 solidified in the flow tube or on the net is picked up by a pair of Nelson rolls, the pickup rolls 11,
It is preferable to wind it once or more so that it does not slip on the yarn and peel it from the net. The surface speed of the pick-up roll must be greater than or equal to the net surface speed. If the pick-up roll surface speed is slower than the net surface speed, the yarn sags between the net and the pick-up roll and eventually cuts. An appropriate ratio between the surface speed of the pickup roll and the surface speed of the net varies depending on the type of polymer solution used and is appropriately selected.

When the polymer solution is a caustic soda aqueous solution of alkali-soluble cellulose, it is preferable to set the pickup roll surface speed to 1.00 times or more and less than 1.36 times the net surface speed. In the case of 1.36 times or more, the yarn is excessively tensioned and finally cut. The yarn separated from the coagulating liquid as described above is appropriately stretched at a predetermined ratio, refined and dried. The refining and drying methods may be the same as in the prior art.

It is preferable that the spinneret 5 is installed in the flow tube holder 3, and the flow tube 7 is installed on the center line of the spinneret 5. If the distance from the spinneret to the flow tube is too short, the yarn will not easily enter the flow tube, and the spinning stability will be low because the coagulating liquid swirls around the spinneret. If it is too long, the liquid resistance between the spinneret surface and the flow tube increases, and the spinning speed does not increase. The preferred inner diameter of the flow tube depends on the denier and number of filaments of the yarn being spun.

For example, when spinning a yarn of 75 denier and 33 filaments, an inner diameter of 3 mmφ to 10 mmφ is preferably used. When the inner diameter is 2 mmφ or less, not only the yarn is difficult to enter the flow tube, but also the spinning stability is lowered due to the contact between the yarn and the inner wall of the flow tube. If the inner diameter is too thick,
The amount of coagulating liquid used to reach a predetermined coagulating liquid speed is large, which is disadvantageous in terms of operation and economy.

The flow tube length is preferably a length required for the yarn to solidify to some extent in the flow tube. If it is too short, when the yarn is shaken off the net, the yarn will be deformed and damaged due to insufficient solidification. It is better to install the flow tube 7 and the net 8 as parallel and as close to each other as possible so that the thread coming out of the flow tube can be smoothly and shaken off to the net without damage. That is, it is installed so that the traveling direction of the coagulating liquid flow coming out of the flow tube is the same as the net traveling direction.

The material of the net is not particularly limited as long as it is not corroded by the coagulating liquid. Net density is, for example, 75
When spinning a denier, 33 filament yarn,
About 10 to 500 mesh is preferable. The warp (net running direction) density of the net is more preferably lower than the weft density in order to improve the releasability of the yarn from the net.

Further, it is preferable that a suction is installed on the net. In order to promptly remove excess coagulation liquid from the net, at least one suction should be installed at a position where the flow of coagulation liquid falls into the net. The length of the net is preferably long enough to remove the coagulating liquid. If the spinning speed is slow, the liquid permeability of the net is good, or the suction is installed, the length of the net can be short. For example, 75 denier,
When a 33-filament yarn is spun at a spinning speed of 200 m / min, a net length of about 50 cm is appropriate if a suction is installed.

In the wet spinning method of the present invention, the tension applied to the yarn can be arbitrarily controlled from zero to the cutting tension regardless of the spinning speed.

[0024]

EXAMPLES The present invention will now be described with reference to examples. The spinning stability was evaluated as follows. ◯: At least 8 hours or more, there was no yarn breakage or single yarn breakage (a part of the filament was cut), and stable winding was possible.

X: The yarn was cut or the single yarn was broken within 5 minutes and could not be wound for 5 minutes or more.

[0026]

Examples 1 to 7 Polymer solutions prepared as described below were spun by the wet spinning apparatus shown in FIG. 100 parts of softwood pulp (Alaska pulp) having a degree of polymerization of 1300 was immersed in 1000 parts of water for 3 hours and then dehydrated with a dehydrator to obtain 180 parts of hydrous cellulose. This water-containing cellulose was subjected to 25 at 235 ° C. using an explosive treatment device (manufactured by Nippon Kagaku Kikai Co., Ltd.).
It was steamed for 2 seconds to obtain an alkali-soluble cellulose having a degree of polymerization of 326.

100 g of this cellulose was dissolved in 1900 g of a 7.8 wt% sodium hydroxide aqueous solution at 4 ° C. using a homogenizer to obtain a uniform polymer solution. The solubility of cellulose was 99%. 2 of the obtained polymer solution
Two 00-mesh wire nets and one polyamide non-woven fabric were used for filtration, depressurized at 5 ° C. and defoamed to obtain a spinning polymer solution. Hereinafter, this polymer solution is referred to as a dope.

The obtained dope was discharged from the spinneret into the coagulation bath in the flow tube holder at a flow rate of 13.5 ml / min. The hole diameter of the spinneret is 0.05 mmφ and the number of holes is 33 holes. The coagulating liquid was 20% by weight of sulfuric acid and the temperature was −7 ° C., and was quantitatively introduced into the flow tube holder so that the average speed of the coagulating bath in the flow tube was 70 m / min to 300 m / min. The coagulation liquid and the yarn pass through the glass flow tube attached to the flow tube holder, and the average speed of the coagulation liquid in the flow tube is 10 m / min.
I shook off the net running at a high surface speed. The distance from the nozzle surface to the flow tube is 20 mm, the inner diameter of the flow tube is 5.8 mmφ, and the length is 300 mm. The flow tube was installed parallel to the net, and the distance between the flow tube and the net was 2 mm or less.

The net is a plain weave of monofilament warp yarns (parallel to the running direction of the net) 78 / inch, weft yarns (perpendicular to the running direction of the net) 61 / inch (manufactured by Nippon Filcon Co., Ltd., trade name FOP-76). , Made of polyester). The coagulation liquid shaken off on the net was forcibly sucked by three suction rolls and two free rolls. Next, the yarn from which the excess coagulation liquid was removed was peeled from the net by using a pickup roll that rotates at a surface speed 1.05 times faster than the surface speed of the net. The pick-up rolls were a pair of Nelson rolls. After one spiral winding of the yarn, the yarn was transferred to a washing roll, thoroughly washed with water, dried with a drier and sampled.

The results are shown in Table 1. ΔV is 10 m / mi
n, the average velocity of the coagulating liquid in the flow tube while keeping the surface velocity of the pickup roll at 1.05 times the net surface velocity,
When the net surface speed and the pick-up roll surface speed were both improved, the yarn speed could reach 325 m / min. At this time, there was no yarn breakage or single yarn breakage (a part of the filament was cut), and the spinning stability was good. Although the yarn speed did not exceed 325 m / min, a feeling that spinning was possible was obtained at a higher speed.

[0031]

Comparative Example 1 The same dope and coagulating liquid as in Examples 1 to 7 were spun by a conventional wet spinning apparatus (FIGS. 2a, 2b and 2c). Using any of the devices a, b, and c in FIG. 2 and changing the spinning conditions drastically (ΔV was −5 m / min)
To 40 m / min. Ratio of pickup roll surface speed Pv and net surface speed Nv, Pv / N
(v was changed from 0.99 times to 1.4 times), and a part 13 of the yarn was taken in the coagulating liquid flow 12 and spinning could not be performed.

[0032]

[Examples 8 to 12 and Comparative Examples 2 and 3] The dope, coagulating liquid and wet spinning apparatus are under the same conditions as in Examples 1 to 7. The results are shown in Table 2. When ΔV was -5 m / min, the yarn was disturbed on the net, the spinning stability was poor, and the strength of the obtained yarn was slightly low, 1.2 g / d (Comparative Example 2). . When ΔV was 0 to 35 m / min, spinning could be stably performed, and the strength of the obtained yarn was 1.75 g / d or more, which was satisfactory physical properties (Examples 8 to 12). When ΔV was 40 m / min, the yarn was cut during the spinning process and sampling was impossible (Comparative Example 3).

[0033]

Examples 13 to 18, Comparative Examples 4 and 5 The dope, coagulating liquid and wet spinning apparatus are the same as those in Examples 1 to 7.
The results are shown in Table 3. The ratio PV / NV of the pickup roll surface speed PV to the net surface speed NV is 1.00 to 1.
At 35, spinning could be stably carried out (Examples 13 to 18). PV
When / NV was 0.99, the yarn slackened between the pickup roll and the net and was finally cut (Comparative Example 4).

When PV / NV was 1.4, the yarn was cut between the pick-up roll and the net and could not be spun (Comparative Example 5).

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

[Table 3]

[0038]

INDUSTRIAL APPLICABILITY The wet spinning method of the present invention has a Young's modulus and elongation in the coagulation process which have been difficult to spin by the conventional flow bath spinning method such as an aqueous solution of alkali-soluble cellulose in caustic soda. It is possible to stably spin a yarn having a low level and the like at a high speed.

[Brief description of drawings]

FIG. 1 is a process drawing schematically showing an example of the wet spinning method of the present invention.

FIG. 2 is an explanatory view schematically showing a state where a yarn is taken out from a coagulation bath of a conventional wet spinning method.

[Explanation of symbols]

 1 Polymer Solution Supply Pipe 2 Spinneret Holder 3 Flow Tube Holder 4 Coagulation Liquid Supply Pipe 5 Spinneret 6 Yarn 7 Flow Tube 8 Net 9 Suction 10 Freeroll 11 Pickup Roll 12 Coagulation Liquid Flow 13 Taken by Coagulation Liquid Flow Part of the yarn

Claims (2)

[Claims] 1. A spinning flow tube is used to flow a coagulating liquid flow,
A flow bath spinning method of spinning a discharged polymer solution as a yarn, wherein the yarn is placed on a net running in the same direction as the coagulating liquid flow together with the coagulating liquid flow flowing out from the spinning flow tube,
A wet spinning method, characterized in that the running speed of the net is made to run at a surface speed not lower than the speed of the coagulating liquid flow, and then the yarn on the net is detached from the net at a speed not lower than the running speed of the net. 2. The wet spinning method according to claim 1, wherein the polymer solution is a caustic soda aqueous solution of alkali-soluble cellulose having a solubility of 90% or more in an alkaline aqueous solution having a concentration of 5 to 15% by weight.