JPH01272809A - Wet spinning - Google Patents

Abstract

PURPOSE:To obtain undrawn yarn free from adhesion between single yarns, by upward delivering a spinning dope from a spinneret set at the lower part of a spinning bath consisting essentially of a solvent, taking off spun yarn above, passing the yarn through a solvent bath having coagulating ability, extracting and removing the solvent in the yarn. CONSTITUTION:An organic polymer is dissolved in a first solvent to prepare a spinning dope and a second solvent consisting essentially of a solvent which has a higher specific gravity than the spinning dope and has no coagulating ability on the organic polymer is prepared as a spinning bath 3. An extracting agent bath 6 is composed of the extracting agent of the first solvent after a third solvent bath 3 having coagulating ability on the organic polymer is set. The spinning dope is upward delivered from a spinneret 2 to the bath 3, taken up by a take-up roll 4, the yarn is coagulated in the bath 5, the first solvent is extracted and removed in the bath 6 and undrawn yarn is wound.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a wet spinning method for an organic polymer solution. The present invention relates to a wet spinning method capable of producing undrawn yarn that becomes a fiber with a high initial elastic modulus.

(Prior Art) Recently, a spinning dope in which a high molecular weight organic polymer is dissolved in a specific solvent is used for spinning. A method for obtaining high-strength, high-modulus fibers using the so-called gel spinning method or dry/wet spinning method has been developed and is attracting attention.

In polyethylene fibers produced by gel spinning method.

Fibers having a strength of 30 g/d or more and an initial elastic modulus of 400 g/d or more have been obtained.

Polyvinyl alcohol (hereinafter abbreviated as PVA) has superior heat resistance and adhesive properties compared to polyethylene fibers.
Regarding fibers, methods for improving both strength and initial elastic modulus are disclosed in JP-A-59-130314 and JP-A-60-1.
No. 26312, JP-A-61-108712,
JP-A-62-238812, JP-A-63-289
1) It has been proposed in Publications, etc.

These methods produce high-strength, This method produces PVA fibers with a high initial modulus of elasticity.

In addition, a wet spinning method for PVA using dimethyl sulfoxide as a solvent and methanol, acetone, toluene, etc. as a coagulating liquid is known from Japanese Patent Publication No. 16675/1983, but in this method, PVA fibers are Despite being stretched 20 times, the strength of the resulting fiber is 10 g/d.
It's nothing more than that.

(Problems to be Solved by the Invention) As described above, various methods for producing polyethylene fibers or PVA fibers having high strength and high initial elastic modulus have been proposed, but in the dry and wet spinning methods described above, spinnerets and The problem is that there is an inert atmosphere layer between the coagulating liquid (cooling liquid).

That is, when the spinning stock solution is extruded from the discharge hole of the spinneret, thick gel-like filaments are formed that are unstable in shape immediately below the spinneret (in the inert atmosphere layer).

Therefore, when extruding the spinning stock solution from a plurality of discharge holes, if the interval between the discharge holes (the distance between one discharge hole and the discharge hole next to it) is narrow.

Each gel-like filament adheres to each other to form a glued yarn, and the glued yarn breaks as a single filament during drawing, making it impossible to increase the drawing ratio, resulting in the problem of not being able to obtain fibers with high strength and high initial elastic modulus. be.

As one way to solve this problem.

It is conceivable to widen the interval between the discharge holes, but this method is possible up to about 100 holes.

When trying to fabricate a spinneret with several hundred holes, which is desired for industrially efficient production, the spinneret becomes extremely thick, which is not only disadvantageous in handling, but also creates a new problem in that it tends to cause uneven discharge between the discharge holes. A problem arises.

On the other hand, with the conventional wet spinning method, although the problem of the formation of sticky yarn does not occur, as mentioned above, the 2-strength is PV
With fiber A, it was only 10 g/d at most, and it was not possible to improve both strength and initial elastic modulus.

The present invention solves the above problems, allows spinning in a stable state without the filaments sticking to each other during spinning, and achieves high strength and high initial elastic modulus by performing drawing treatment in the subsequent process. A technical object of the present invention is to provide a wet spinning method that can produce undrawn yarn that becomes fibers with high productivity.

(Means for Solving the Problems) In view of the current situation, the inventors of the present invention have conducted intensive studies and have arrived at the present invention.

That is, the present invention has a first-order configuration.

(1) Prepare a spinning stock solution by dissolving an organic polymer in a first solvent, and then use a second solvent whose main component is a solvent that has a higher specific gravity than the spinning stock solution and does not have the ability to coagulate the organic polymer. The spinning stock solution is discharged upward from a spinneret provided at the lower part of the spinning bath and taken up above. A wet spinning method characterized in that after forming the yarn, the first solvent in the yarn is removed using an extractant.

(2) Prepare a spinning stock solution by dissolving the organic polymer in a first solvent, and add a second solvent as a lower layer, the main component of which is a solvent that has a higher specific gravity than the spinning stock solution and does not have the ability to coagulate the organic polymer. The lower part of the spinning bath consists of two baths, the upper layer of which is a third solvent which has a lower specific gravity than the second solvent, has coagulation ability for organic polymers, and has a limited mutual solubility with the second solvent. A wet spinning method characterized in that the spinning dope is discharged upward from a spinneret provided in the spinneret to form yarn through the two baths, and then the first solvent in the yarn is removed with an extractant. .

Hereinafter, one aspect of the present invention will be explained in detail.

The organic polymer in the present invention is polyethylene.

Polyolefin polymers such as polypropylene, ethylene/propylene copolymer, vinyl polymers such as PVA, polyacrylonitrile, polyvinylidene fluoride, etc.2 Polyamide polymers such as various types of nylon, polyester polymers such as polyethylene terephthalate The present invention particularly refers to a polymerization degree of 1 or a mixture thereof.
Suitable for spinning PVA polymers of 500 or more.

In the present invention, the first solvent used to dissolve the organic polymer and prepare the spinning dope is:

When the organic polymer is a polyolefin polymer.

Various hydrocarbons2 e.g. decalin, xylene.

Tetralin, cyclohexane, nonane, decane.

It may be selected from paraffin oil, naphthalene, etc. and mixtures thereof.

Also, when the organic polymer is a vinyl polymer.

It may be selected from saturated aliphatic polyhydric alcohols such as glycerin, ethylene glycol, propylene glycol, dimethyl sulfoxide, water, etc., and mixtures thereof. In the case of PVA-based polymers suitable for the present invention, glycerin, ethylene glycol, etc. , dimethyl sulfoxide, water or mixtures thereof are preferably used.

When the organic polymer is a polyamide polymer or a polyester polymer, benzyl alcohol, formic acid, etc., or benzyl alcohol, 0-chlorophenol, acetic acid dichloride, etc. can be used, respectively.

In the present invention, the specific gravity is higher than that of the spinning dope.

Moreover, it is important to discharge the spinning solution from a spinneret provided at the lower part of the second solvent bath, which is mainly composed of a solvent that does not have the ability to coagulate organic polymers.

That is, by discharging into the second solvent whose main component is a solvent having a higher specific gravity than the spinning dope, the discharged spinning dope flow receives buoyancy caused by the difference in specific gravity between the spinning dope and the second solvent. Moreover, since the second solvent is mainly composed of a solvent that does not have the ability to coagulate the organic polymer, the discharged spinning stock solution flow rises while remaining in a solution state. Furthermore, since the second solvent is present between each spinning stock solution flow discharged from each discharge hole, there is no possibility of sticking between filaments (it is possible to spin multifilaments in an extremely stable state). It becomes possible.

Further, as described above, since the spinning dope flow rises due to buoyancy, the spinning dope needs to be discharged upward. If the spinning dope is discharged downward, the spun solution will adhere to the spinneret surface, making spinning difficult.If the spinning dope is discharged downward, sideways or diagonally, the buoyancy will act sideways, resulting in undrawn materials for high-strength, high-modulus fibers. It becomes difficult to obtain thread.

As the second solvent, various solvents can be used depending on the combination of the organic polymer and the first solvent, and those skilled in the art can easily select an appropriate solvent. For example, water is suitable when spinning a spinning stock solution in which polyethylene is dissolved in paraffin oil. Also, when spinning a spinning stock solution in which a PVA polymer is dissolved in dimethyl sulfoxide.

It is preferable to use a solvent containing tetrachlorethylene as a main component.

The second solvent used in the present invention is mainly composed of a solvent that does not have the ability to coagulate the organic polymer, but it may be mixed with a solvent that has a coagulation ability as appropriate to the extent that the spinning stock solution does not completely coagulate. .

In the present invention, the gel-like filament discharged into the second solvent bath is once taken up above and then introduced into the third solvent bath which has the ability to coagulate the organic polymer.

Forms coagulated threads. (First invention) In addition, when the third solvent has a lower specific gravity than the second solvent and has a finite solubility with the second solvent, a third solvent bath is provided above the second solvent bath, The gel-like filaments may be continuously conducted from the second solvent bath to a third solvent bath to form a coagulated thread.

(Second invention) As the third solvent, it is possible to apply a solvent used in conventionally known dry/wet spinning methods or wet spinning methods, but if necessary, other components may be mixed. good. When spinning a PVA-based polymer solution suitable for the present invention, it is preferable to use metal or acetone as the third solvent.

Since the coagulated thread obtained above still contains the first solvent, it is necessary to extract and remove the first solvent with an extractant.

In other words, if the yarn containing the first solvent is dried or hot-stretched in the subsequent steps, the first solvent will ooze out onto the surface of the single yarns constituting the yarn, resulting in inter-filament agglutination. .

Any extractant may be used as long as it has affinity with the second and first solvents, and those skilled in the art can easily select an appropriate extractant. In addition, the same extractant as the third solvent may be used, and in the case of the first invention in which the second solvent bath and the third solvent bath are separated, the third solvent bath is used to remove the yarn. Coagulation and extraction removal of the first solvent may be performed simultaneously.

The undrawn yarn obtained by the method of the present invention is once wound up or continuously supplied to a drawing step and drawn. In the present invention, during this period, drying, oil treatment, and other steps may be appropriately introduced if necessary.

Various methods can be used as the stretching method.9 For example, a method in which the undrawn yarn is stretched while being in contact with a heating body such as a heat plate, a method in which the yarn is stretched in a hot air bath such as a heat oven, and a method in which the yarn is stretched in a hot air bath such as a heat oven; Examples include a method in which the material is stretched in a medium, and a method in which the material is stretched using a dielectric heating method. In these methods, 1
Stretching can be done in stages or in multiple stages of 2 or more stages, but 2
It is preferable to stretch in multiple stages, and in the case of multi-stage stretching, it is also possible to add moisture, oil, etc. between the nth stage stretching and the n+1th stage stretching (n is an integer of 1 or more). good.

Next, two aspects of the present invention will be explained with reference to the drawings.

FIG. 1 is a schematic process diagram showing an implementation BjR of the first invention in which the second solvent bath and the third solvent bath are separated.

The spinning stock solution supplied from the conduit 1 is discharged upward from the spinneret 2 into the second solvent bath 3, taken off by the take-up roller 4, and then passed through the third solvent bath 5 to solidify the yarn. The first solvent is extracted and removed in an extractant bath 6, and the undrawn yarn is wound up.

Further, FIG. 2 is a schematic process diagram showing an embodiment of the second invention, in which the spinning dope is discharged into a spinning bath having a second solvent bath 3 as a lower layer and a third solvent bath 5 as an upper layer, and is taken up. After being taken up by rollers 4, the first solvent is extracted and removed in an extractant bath 6, and the undrawn yarn is wound up.

(Function) According to the present invention, filaments can be spun in a stable state without sticking to each other during spinning, and high strength can be achieved by performing a drawing process in the subsequent process.

It is possible to produce undrawn yarns that result in fibers with high initial elastic modulus with high productivity.

In the present invention, the following is considered to be the reason why it is possible to obtain an undrawn yarn that becomes a fiber with high strength and high initial elastic modulus by performing drawing treatment in a subsequent step.

That is, by wet spinning upward into a second solvent whose main component is a solvent that has a higher specific gravity than the spinning dope and does not have the ability to coagulate organic polymers.

It is possible to provide an effect similar to that of an inert atmosphere layer in dry and wet spinning methods, in which the discharged spinning stock solution flow is stretched upward in a solution state, in a solvent, and in addition, the solvent is present between the filaments. This is thought to be because the adhesion between single yarns does not occur, and the advantages of both the dry/wet spinning method and the wet spinning method are synergistically expressed.

(Example) The present invention will be specifically explained below with reference to two examples.

In addition, the strength and initial elastic modulus in the examples are based on a sample length of 20 cM.
, which is the value obtained when a tensile test was conducted at a tensile speed of 20 cm/min (20° C., 65% RH).

Example 1 Polymerization degree 4800 (7) PVA (care degree 99.
9 mol %) was dissolved in dimethyl sulfoxide at 120°C to prepare a spinning stock solution having a +ta content of 12 wt %. As shown in Figure 2.

Lower layer is tetrachlorethylene 99-t%9 methanol 1
wt% (depth 10 ports), upper layer methanol 64-t%.

In the lower layer of a two-bath spinning bath consisting of 32-t% tetrachlorethylene and 4 wt% water
A spinneret (mouth diameter: 80fi) with a length of 3 m and 320 holes was installed, and the above-mentioned spinning dope was discharged upward from the spinneret to form a yarn through the two baths, and then through an extraction bath consisting of methanol. After sufficiently extracting dimethyl sulfoxide, it was dried in hot air at a temperature of 60° C. and then wound to obtain a dry undrawn yarn.

When the cross section of this dried undrawn yarn was observed under a microscope, no adhesion between the filaments was observed.

The dried undrawn yarn obtained above was stretched to 14 times, which corresponds to 95% of the maximum stretching ratio, in a hot air bath set at an inlet temperature of 140°C and an outlet temperature of 245°C, and then wound up.

A drawn yarn was obtained.

The obtained drawn yarn has a fineness of 550 d and a strength of 19.5 g/d.
, the initial elastic modulus was 533 g/d.

Comparative example 1 In Example 1, the spinning bath contained 64 wt% methanol.

Wet spinning was performed in the same manner and extracted using only a solvent consisting of 32 wt% tetrachlorethylene and 4 wt% water.

It was dried to obtain a dry undrawn yarn. This dry undrawn yarn has
There is no sticking between the filaments at all.

Although it was possible to draw the yarn 19 times, the obtained drawn yarn 4
The strength of 00d was only 8.7 g/d.

Comparative example 2 In Example 1, the spinning bath contained 64-t% methanol.

Dry/wet spinning was performed by changing only the solvent consisting of 32-t% tetrachlorethylene and 4 wt% water. The thickness of the inert atmosphere layer at this time was 50 mm.

When the cross section of the obtained dry undrawn yarn was observed under a microscope, there were 37 filaments that appeared to be two single yarns stuck together, and one filament that seemed to be three single yarns stuck together. There was one.

Example 2 Linear high-density polyethylene with a weight average molecular weight of 400,000 was dissolved in paraffin oil at 150°C to prepare a spinning stock solution with a concentration of 5 wt%. As shown in Figure 1.

The spinning dope is discharged upward from a spinneret with a hole diameter of 0.7 m and a number of holes of 320 installed in a spinning bath (depth 15 cn+) using water, passed through the spinning bath, and then taken out at 9 Next, the sample was passed through a methylene chloride bath that served as a third solvent and an extractant, and the paraffin oil was sufficiently extracted and rolled up, followed by drying in a nitrogen stream at room temperature.

Obtain dry undrawn yarn.

When the cross section of the obtained dried undrawn yarn was observed under a microscope, no adhesion between the filaments was observed.

This dried thread was heated at 50°C using a heat plate at 135°C.
A drawn yarn was obtained by drawing the yarn twice as much. The obtained drawn yarn 65d is 2
It had high strength and initial elastic modulus of 48 g/d and initial elastic modulus of 1700 g/d.

(Effects of the Invention) Since the present invention has the above-mentioned configuration, two according to the present invention:
During spinning, the filaments do not stick to each other and can be spun in a stable state, and are stretched in subsequent steps to achieve high strength.

It is possible to produce undrawn yarn that becomes a fiber with a high initial elastic modulus with good productivity.

Further, according to the first invention in which the second solvent bath and the third solvent bath are separated, the second solvent and the third solvent can can be freely selected.

Furthermore, according to the second invention, which uses a spinning bath in which the second solvent bath is the lower layer and the third solvent bath is the upper layer, it is possible to downsize the spinning apparatus.

[Brief explanation of the drawing]

FIG. 1 is a schematic process diagram showing one embodiment of the first invention, and FIG. 2 is a schematic process diagram showing one embodiment of the second invention. 1 - - - - Conduit 2 - - Spinneret 3 - - - Second solvent bath 4 - - Take-up roller 5 - - - Third solvent bath 6 - - -・Extractant bath

Claims (2)

[Claims] (1) Prepare a spinning stock solution by dissolving an organic polymer in a first solvent, and then use a second solvent whose main component is a solvent that has a higher specific gravity than the spinning stock solution and does not have the ability to coagulate the organic polymer. The spinning stock solution is discharged upward from a spinneret provided at the lower part of the spinning bath and taken up above, and then passed through a third solvent bath having the ability to coagulate the organic polymer to form the yarn. A wet spinning method characterized in that after forming the yarn, the first solvent in the yarn is removed using an extractant. (2) Prepare a spinning stock solution by dissolving the organic polymer in a first solvent, and add a second solvent as a lower layer, the main component of which is a solvent that has a higher specific gravity than the spinning stock solution and does not have the ability to coagulate the organic polymer. The lower part of the spinning bath consists of two baths, the upper layer of which is a third solvent which has a lower specific gravity than the second solvent, has coagulation ability for organic polymers, and has a limited mutual solubility with the second solvent. A wet spinning method characterized in that the spinning dope is discharged upward from a spinneret provided in the spinneret to form yarn through the two baths, and then the first solvent in the yarn is removed with an extractant. .