JP2017141524A - Manufacturing method of synthetic fiber yarn - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of synthetic fiber yarn improving productivity without spoiling process stability.SOLUTION: In a manufacturing method spinning synthetic fiber by discharging spinning solution from a spinneret into solidifying medium, the spinneret has more than 1,000 of nozzle holes, the nozzle holes are arranged in a rectangle form, and when the long side of the rectangle is (a) and the short side is (b), the ratio (a)/(b) is 5-50. It is preferable that the plural spinnerets exist and are discharged into the same solidifying medium, and the spinning is wet-spinning or dry-wet-spinning.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing a synthetic fiber yarn, and more particularly, to a method for producing a synthetic fiber yarn that performs wet or dry wet spinning using a coagulation bath.

  In the production of synthetic fibers, it has been recognized as an important issue to increase production volume and improve production efficiency without impairing process stability. For example, increasing the running speed of the yarn or forming the nozzle holes formed in the spinneret nozzle with high density has been studied.

  However, when the running speed of the yarn is simply increased, process failures such as yarn breakage occur, and the productivity is reduced. In addition, as a normal spinneret, a circular nozzle base in which nozzle holes are arranged in a circle on the base surface is common, but when a large number of nozzle holes are arranged at a high density, the fiber just after passing through the spinneret is used. There was a problem in that coagulation was incomplete and adhesion between single yarns or yarn breakage occurred, resulting in a deterioration in spinning tension. In addition, when using a rectangular nozzle base in which the nozzle holes are arranged in a rectangle so as to reduce the gap between the nozzle hole and the solidification bath as much as possible, in general, the number of nozzle holes is often larger than that of the circular nozzle base. In other words, it was difficult to maintain a good spinning tone.

  In particular, such productivity problems are remarkable when performing wet or dry wet spinning in which coagulation is performed in a liquid bath. When coagulation is performed in a liquid bath, the coagulation liquid is not renewed and tends to stay between the fiber yarns, and the necessary amount of fresh coagulation liquid is not supplied to the fiber yarns. This is because an unsolidified portion is likely to occur. In the wet or dry wet spinning process of synthetic fibers, the spinning solution discharged from the die is coagulated in a coagulation bath to be fiberized, but if the nozzle holes are arranged at high density, the coagulation bath However, there was a problem that the solvent could not be extracted sufficiently.

  Therefore, for example, a technique has been studied in which a gap is provided between the nozzle holes of the die (Patent Document 1), or the nozzle nozzle hole density is changed between the peripheral part and the central part (Patent Document 2). However, these methods complicate the structure of the die and do not necessarily contribute to the improvement of productivity. For example, when the nozzle hole density is partially changed, a lot of coagulation liquid flows in locally between low-density nozzle holes, and the flow of the coagulation liquid is disturbed to often shake each single yarn constituting the yarn, There was a problem that defects such as uneven thickness of the finally obtained yarn and occurrence of yarn breakage during production occurred.

JP 2001-348722 A JP 2009-263805 A

  The present invention was made in order to solve the problems of the prior art described above, and the object of the present invention is to improve the productivity of synthetic fiber yarns without impairing process stability. It is to provide a manufacturing method.

The synthetic fiber yarn production method of the present invention is a production method of spinning a synthetic fiber by discharging a spinning solution from a spinneret into a coagulation bath, wherein the spinneret has 1000 or more nozzle holes, A hole is arrange | positioned at a rectangle and ratio (a) / (b) of the long side (a) and short side (b) of the rectangle is 5-50, It is characterized by the above-mentioned.
Furthermore, it is preferable that there are a plurality of spinnerets and that they are discharged into the same coagulation bath, and that the spinning is wet spinning or dry wet spinning. Moreover, it is preferable that a synthetic fiber is an acrylic fiber.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the synthetic fiber yarn which improves productivity, without impairing process stability is provided.

  The method for producing a synthetic fiber yarn of the present invention relates to a production method for spinning a synthetic fiber by discharging a spinning solution from a spinneret into a coagulation bath. The synthetic fiber obtained by the production method of the present invention may be a fiber using so-called wet spinning or dry wet spinning in which a synthetic resin in a spinning solution is solidified using a coagulation bath. Specifically, rayon, acrylic Preferred examples include synthetic fibers made of organic polymers such as wholly aromatic polyamides.

Among these, the production method of the present invention is suitable for acrylic fibers. In that case, although it can apply also to the acrylic fiber for clothes, it is preferable that it is an industrial acrylic fiber in which especially a high performance physical property is requested | required. Among them, an industrial acrylic fiber that requires roundness as a cross-sectional shape of the fiber, particularly an industrial acrylic fiber that is used for the production of carbon fiber and flame resistant fiber that is a precursor thereof is preferable. .
In the synthetic fiber yarn manufacturing method of the present invention, the spinneret for discharging the spinning solution has 1000 or more nozzle holes, the nozzle holes are arranged in a rectangular shape, and the rectangular long side (a) and the short side The ratio (a) / (b) of side (b) needs to be 5-50.

  Furthermore, the ratio (a) / (b) of the long side (a) to the short side (b) of the rectangular block group in which the nozzle holes are arranged is in the range of 7 to 30, and A range of 5 to 15 is preferable. The spinning solution is preferably discharged sideways into the coagulation bath, and more preferably installed such that the long side is in the depth direction and the short side is in the horizontal direction. Here, when the ratio (a) / (b) is too small, the width in the short side direction becomes large, and it is necessary to reduce the number of nozzles that can be arranged in the coagulation bath or to increase the width of the coagulation bath. Resulting in reduced efficiency. On the other hand, when the ratio (a) / (b) is too large, quality spots are generated at the center and the end in the long side direction of the block group arranged in the rectangle of the nozzle hole.

  In the spinneret used in the present invention, the number of fibers ejected from the nozzle hole block group arranged in the rectangle needs to be 1000 or more (hereinafter referred to as “1000” as “1K”). ), Preferably 3000 to 100,000 (3K to 100K), more preferably 5000 to 50,000 (5K to 50K), particularly 10,000 to 25,000 (10K to 25K) It is preferable to be in the range. Usually, when there are a large number of nozzle holes and fibers, the fiber density in the coagulation bath increases and coagulation tends to be non-uniform. However, in the present invention, the ratio of short side / long side is 5 times or more. By adopting the arrangement of special long and narrow nozzle holes, it became possible to suppress the physical property fluctuation of each obtained single fiber.

Preferably the pore density in the range of the rectangle is in the range of 2 to 10 / mm ² in yet present invention, and more preferably in the range of 3 to 6 / mm ^2. The present invention is particularly effective when the intervals between the nozzle holes are small and the discharge holes are densely arranged. The diameter of the nozzle hole is preferably in the range of 0.01 to 1 mm.

  In the present invention, it is preferable that there are a plurality of groups (hereinafter sometimes referred to as “nozzle hole block groups”) of nozzle holes arranged in a rectangular shape as described above. Furthermore, those rectangular nozzle hole block groups can also be divided into a single nozzle to form a plurality of nozzle hole block groups, but each rectangular nozzle hole block group is disposed on a separate single spinneret, It is preferable that the nozzle hole block group constitutes one weight (hereinafter sometimes referred to as “nozzle weight”). This is because each nozzle hole block group exists independently as a nozzle weight, and it becomes possible to have a structure in which the coagulating liquid flows between the spinning nozzle weights. In this way, when there are multiple spinning nozzle weights and they are discharged into the same coagulation bath, the coagulating liquid convects between the spinning nozzle weights and the spinneret so that the coagulating liquid becomes more uniform. is there.

  Further, since the nozzle hole block group in the present invention has a very long and narrow rectangular shape, even if a plurality of nozzle hole block groups and nozzle weights are arranged in one coagulation bath, the installation area is reduced. Can be suppressed. For example, even when a coagulation bath of the same size as the conventional one is used, a large number of high-quality fibers can be easily manufactured by increasing the number of nozzle hole block groups and nozzle weights to be installed. It becomes possible. The number of such nozzle hole block groups and nozzle weights is preferably 50 or less, and particularly preferably 2 to 20.

  The arrangement of the spinneret having the rectangular nozzle hole block group is preferably in the horizontal direction in the case of wet spinning in which the spinneret is present in the coagulation bath. Furthermore, it is preferable to use a transverse spinneret in which the short side of the nozzle hole block group is arranged in parallel with the water surface of the coagulation bath and the long side is arranged in the depth direction of the coagulation bath. In that case, the coagulating liquid convects along the depth direction of the long side, the coagulating liquid is easily exchanged between the surface of the coagulating bath and the deep part of the coagulating bath, and the quality of the resultant synthetic fiber is stabilized. In addition, since the short side of the horizontally oriented nozzle hole block group is parallel to the water surface of the coagulation bath, it is possible to efficiently arrange the coagulation bath in a small installation area.

  When a plurality of such rectangular nozzle hole block groups are employed, the nozzle hole block groups are preferably arranged at intervals of 15 mm or more, more preferably in the range of 30 to 300 mm, particularly It is preferable to arrange them with an interval in the range of 50 to 200 mm. This is because if the interval between the nozzle hole block groups is too narrow, even if rectangular nozzle hole block groups are employed, the renewal of the coagulating liquid is prevented and the coagulating liquid tends to stay. As a result, there is a portion where it is difficult to supply the amount of fresh coagulation liquid necessary for coagulation of the fiber, so that the solvent cannot be sufficiently extracted from the spinning solution. Tends to get worse.

  Further, when each nozzle hole block group arranged in the coagulation bath constitutes one nozzle weight, a partition plate (rectifying plate) is installed between each of these plurality of nozzle weights, It is preferable to rectify the flow. By arranging the current plate in the coagulation bath in this way, the flow of the coagulation liquid between the nozzle weights can be controlled more easily.

  The synthetic fiber yarn production method of the present invention is a so-called wet spinning method or dry-wet method in which a spinning solution is discharged from a spinneret into a coagulation bath by using a spinneret as described above to spin a synthetic fiber. This is a manufacturing method called a spinning method. Among them, the production method of the present invention is optimal for the production of acrylic fibers, as described above, and is a production of acrylic fibers for industrial use that require particularly high-performance physical properties, as well as the production and precursors of carbon fibers. It is particularly preferably used for industrial acrylic fibers used in the production of flame resistant fibers.

Hereinafter, the detailed preferable conditions of the production method of the present invention will be further described with a focus on the production method of the acrylic fiber particularly optimally used.
A preferred spinning solution used for the production of acrylic fibers is not particularly limited as long as it is a spinning solution containing an acrylonitrile polymer, but preferably 90% by mass or more of acrylonitrile as a polyacrylonitrile polymer, and more It is preferable that it is the polymer which homopolymerized or copolymerized the monomer containing 95-99 mass%. In particular, the composition of the polyacrylonitrile polymer most suitable for the production method of the present invention includes 90 to 99% by mass of an acrylonitrile monomer and 1 to 10% by mass of a comonomer copolymerizable with acrylonitrile having a vinyl skeleton. It is preferably a coalescence. Examples of the comonomer copolymerizable with acrylonitrile include acids such as acrylic acid and itaconic acid and salts thereof, acrylic acid esters such as methyl acrylate and ethyl acrylate, and amides such as acrylamide. One or a combination of two or more can be used depending on the fiber properties. Among these, it is preferable to use methyl acrylate and itaconic acid in combination.

  Incidentally, such a polyacrylonitrile polymer for the spinning solution can be obtained by adopting any known method such as solution polymerization or suspension polymerization as the polymerization method. As the polymerization catalyst used in the polymerization reaction, a known catalyst can be used as appropriate according to the polymerization method. For example, in the case of a polyacrylonitrile-based polymer, a radical polymerization catalyst such as an azo compound or a peroxide, a redox catalyst, etc. Can be used. When using a redox catalyst, for example, sodium bisulfite, ammonium bisulfite, alkyl mercaptans, sodium bisulfite, ammonium bisulfite as reducing agents, potassium persulfate, sodium persulfate, ammonium persulfate, chlorite as oxidizing agents Examples thereof include sodium and ammonium persulfate.

  In order to spin such a polymer, the polymer is preferably diluted with a solvent and used as a spinning solution. As the solvent used in the spinning solution, a known solvent can be used. For example, in the case of a polyacrylonitrile polymer, an aqueous solution of an inorganic compound such as zinc chloride or sodium thiocyanate, dimethylacetamide, dimethylsulfoxide, dimethylformamide, etc. These organic solvents are mentioned. The concentration at the time of using these spinning solutions is not particularly limited. However, in the case of an acrylonitrile polymer, the amount of the solvent is preferably adjusted to 5 to 40% by mass, and 6 to 30% by mass. It is more preferable to set it as 7-18 mass%.

  In the production method of the present invention, the spinning dope obtained as described above is spun by a normal wet spinning method or a dry wet spinning method, that is, the spinning solution is discharged from a spinneret into a coagulation bath to obtain a synthetic fiber. Spin. Furthermore, it is preferable that the synthetic fiber yarn thus coagulated and spun is then drawn. The stretching method is preferably performed in a bath, and may be performed directly on the spun yarn, or it is also preferable that the spun yarn is washed once with water and the solvent is removed. For example, when an acrylonitrile fiber is stretched in a bath, it is usually preferably stretched about 2 to 10 times in a stretching bath at 25 to 98 ° C.

  After the synthetic fiber yarn obtained by the production method of the present invention is stretched in the bath as described above, it is preferable to further apply an oil agent, preferably a silicone oil agent, to the yarn. And it is also preferable to perform the further extending | stretching process (post-drawing process) with respect to the synthetic fiber yarn to which the oil agent was provided. For example, when the synthetic fiber is an acrylonitrile fiber for carbon fiber, the draw ratio in the post-drawing treatment is preferably 1.0 to 2.5 times in order to obtain a carbon fiber precursor fiber. When the draw ratio is within this range, the orientation of the precursor fiber can be increased while suppressing fuzz and yarn breakage, and thus it becomes easy to obtain high-strength carbon fibers. When the draw ratio becomes too high, yarn breakage and fluff increase, and the process passability and the quality of the carbon fiber precursor tend to decrease.

The synthetic fiber yarn obtained by the production method of the present invention can increase the number of nozzle holes in the coagulation bath without impairing process stability, and can improve productivity. .
Further, when an acrylic yarn for carbon fiber is produced by the production method of the present invention, it can be used as a high-quality carbon fiber by further performing a flameproofing treatment and a firing treatment.

  EXAMPLES Hereinafter, although an Example etc. demonstrate this invention further in detail, this invention is not limited by these Examples.

[Measurement method of fiber spots]
In addition, 50 fineness spots were randomly collected from the obtained synthetic fiber yarn, the fineness of each single fiber was measured, and the standard deviation of the measurement result was shown as a coefficient of variation (CV).

[Example 1]
An acrylonitrile polymer composed of 95% by mass of acrylonitrile, 4% by mass of methyl acrylate, and 1% by mass of itaconic acid is dispersed for 10 minutes at a rate of 18% by mass with respect to 100% of dimethylacetamide cooled to 10 ° C. After degassing under reduced pressure at a pressure of 10 MPa for 10 minutes, the mixture was heated to 80 ° C. and dissolved to obtain a spinning dope.
The obtained spinning dope was discharged from a die (nozzle weight) having nozzle holes into a coagulation bath to obtain a wet-coagulated synthetic fiber yarn.
The nozzle holes have a total number of 12000 with a diameter of 0.075 mm, the pitch of each nozzle hole is 0.5 mm, the nozzle hole density is 4.10 / mm ² , and the long side (a) and the short side of the nozzle hole block group The nozzle hole was such that the ratio (a) / (b) of (b) was 7.7. The coagulation bath is filled with an aqueous dimethylacetamide solution having a concentration of 67% by mass and a temperature of 35 ° C., and there is a gap of 7.5 mm between the nozzle hole block group and the outer frame of the coagulation bath, The nozzle holes were installed sideways in the coagulation bath, with the long side in the depth direction and the short side in the horizontal direction.
The resultant synthetic fiber yarn was desolvated in a water washing tank having a temperature gradient of 25 to 95 ° C. and wet-stretched 7.5 times. Next, the obtained fiber yarn was immersed in a silicone-based oil agent bath to give an oil agent, and dried and densified with a roller having a surface temperature of 190 ° C. And after extending | stretching 2.05 times, it passed the cold roller and wound up on the bobbin, and finally the synthetic fiber yarn which is an acrylonitrile-type polymer fiber bundle was obtained. Further, the obtained acrylonitrile-based polymer fiber bundle was used as a precursor fiber for carbon fiber, and then subjected to flameproofing treatment and firing treatment to obtain high-quality carbon fiber.
The resulting synthetic fiber yarns and carbon fibers were less likely to generate single yarn fluff even in subsequent steps such as drawing, and the process passability was also good. Table 1 shows the process conditions and physical properties of the synthetic fiber yarn.

[Example 2, Comparative Example 1]
A nozzle in which the ratio (a) / (b) of the long side (a) to the short side (b) of the nozzle hole block group is changed to 13.8 (Example 2) and 4.9 (Comparative Example 1) is used. A synthetic fiber yarn and carbon fiber, which are acrylonitrile-based polymer fiber bundles, were obtained in the same manner as in Example 1 except that. In all cases, the occurrence of single yarn fluff was small and the process passability was good. Table 1 shows the process conditions and physical properties of the synthetic fiber yarn.

[Example 3]
In the same manner as in Example 1 except that the nozzle weights each having one nozzle hole block group in the base are changed from one to two in Example 1 and arranged side by side, an acrylonitrile-based polymer fiber bundle is used. A synthetic fiber yarn and carbon fiber were obtained. The distance from the center of the short side of the nozzle hole block group between the two nozzles was 120 mm, and the overall width of the coagulation bath was 240 mm.
The resulting synthetic fiber yarns and carbon fibers were less likely to generate single yarn fluff even in subsequent steps such as drawing, and the process passability was also good. Table 1 shows the process conditions and physical properties of the synthetic fiber yarn.

[Example 4, Comparative Example 2]
A nozzle in which the ratio (a) / (b) of the long side (a) to the short side (b) of the nozzle hole block group is changed to 13.8 (Example 4) and 4.9 (Comparative Example 2) is used. A synthetic fiber yarn and carbon fiber, which are acrylonitrile-based polymer fiber bundles, were obtained in the same manner as in Example 3 except that. In all cases, the occurrence of single yarn fluff was small and the process passability was good. Table 1 shows the process conditions and physical properties of the synthetic fiber yarn.

Claims (4)

  A method of spinning a synthetic fiber by discharging a spinning solution from a spinneret into a coagulation bath, wherein the spinneret has 1000 or more nozzle holes, the nozzle holes are arranged in a rectangular shape, and the long side of the rectangle A method for producing a synthetic fiber yarn, wherein the ratio (a) / (b) of (a) to the short side (b) is 5 to 50.   The method for producing a synthetic fiber yarn according to claim 1, wherein a plurality of spinnerets are present and discharged into the same coagulation bath.   The method for producing a synthetic fiber yarn according to claim 1 or 2, wherein the spinning is wet spinning or dry wet spinning.   The method for producing a synthetic fiber yarn according to any one of claims 1 to 3, wherein the synthetic fiber is an acrylic fiber.