JP2001049523A - Production of acrylic fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain acrylic fibers excellent in process passability with filament- filament sticking restrained, through such steps that undrawn filaments are introduced into a bath, carried continuously through a roll with the outer circumference bearing members supporting the filaments along with removing the solvent on the filaments through washing, and the resultant filaments are drawn. SOLUTION: The acrylic fibers are obtained through the following steps: an acrylic polymer solution is spun into a filament yarn 2,000-5,000 in filament yarn density index M defined by the formula: M = filament yarn total fineness d (d: denier)/filament yarn width (mm) and 3,000-20,000 in the number of single filaments constituting the yarn, the filament yarn is then introduced into a bath 1 and carried continuously through a roll 6 with the outer circumference bearing members supporting the filament yarn while removing the solvent adhered to the filament yarn by washing, and subsequently the resultant filament yarn is drawn; wherein it is preferable that the above members are disposed at equal intervals on the outer circumference of the roll 6 and the number of these members is 6-24/roll.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an acrylic fiber for improving the washing efficiency of a spun yarn and obtaining a high-quality acrylic fiber with little adhesion between single yarns, and an acrylic yarn. The present invention relates to an in-bath washing device.

[0002]

2. Description of the Related Art Acrylic fibers are used as precursor fibers of carbon fibers (hereinafter abbreviated as "precursors"), and various production methods have been proposed in order to obtain high-quality carbon fibers.

[0003] The carbon fiber is subjected to a flame-proofing step in which an acrylic fiber as a precursor is made to be flame-resistant in an oxidizing atmosphere.
A material obtained by undergoing a carbonization step of heating to 00 to 2500 ° C and carbonizing, used as a reinforcing fiber for composite materials, and widely used in various applications such as aerospace applications, sports applications, and general industrial applications. .

[0004] In order to meet a wide variety of demands in general industrial applications, it is necessary to reduce the production cost and provide a large amount of inexpensive carbon fibers. Conventionally, many techniques for improving the performance of carbon fibers have been proposed, but none of them has greatly contributed to the reduction of manufacturing costs.

In the production of a precursor, the number of single yarns constituting the yarn to be treated is increased (thick yarn), the yarn density is increased, and the yarn conveying speed in the process is increased. Improving productivity is important for reducing manufacturing costs.

[0006] The process of manufacturing a precursor generally comprises:
After spinning the polymer solution to form a yarn, washing, drawing in a bath, and applying an oil agent to dry and densify, the acrylic yarn to be spun has a large diameter and a high diameter. If the density is increased or the yarn transport speed is increased, adhesion between single yarns will occur in the washing process, washing will be insufficient, and not only will the process passability during manufacturing be greatly impaired, but also in the subsequent firing process Yarn breakage and fluff were induced, and the quality of the obtained carbon fiber was greatly reduced.

[0007] Regarding the cleaning step, see Japanese Patent Application Laid-open No. 57-429.
No. 17, JP-A-61-108715, JP-A-64-68559, JP-A-64-85305, JP-A-64-85306, JP-A-5-140
No. 815 discloses such an improved technique.

[0008] Japanese Patent Application Laid-Open No. 57-42917 discloses a technique in which a heating device is provided in a bath tub to bring a cleaning liquid into a boiling state, and a yarn is passed through the cleaning liquid to increase the cleaning efficiency. According to this, the liquid flow hits the yarn in a direction perpendicular to the yarn, so that the yarn is efficiently heated and at the same time the washing efficiency is increased.However, the liquid flow is small unless the washing liquid is substantially in a boiling state. In other words, the washing efficiency was lowered, and on the other hand, when the washing liquid was in a boiling state, the adhesion between single yarns was rather increased.

Japanese Patent Application Laid-Open No. 61-108715 discloses a technique for cleaning a yarn under irradiation of ultrasonic waves of 10 to 90 kHz to improve the cleaning efficiency. According to this, the cleaning efficiency was improved when the cleaning device was relatively small, but sufficient cleaning efficiency could not be obtained for large-diameter or high-density yarns. Then, it becomes difficult to uniformly irradiate ultrasonic waves uniformly to all of the yarns, and the practicality is poor.

[0010] Further, JP-A-64-68559,
JP-A-64-85305, JP-A-64-8530
No. 6 discloses that a cleaning liquid is sprayed from a guide for changing the direction of a yarn in a washing step and a hot water drawing step,
There is disclosed a technique for improving the efficiency of washing a yarn and at the same time suppressing the adhesion between single yarns. According to this, a sufficient cleaning effect cannot be obtained for a large-diameter or high-density yarn, and the cleaning effect is further reduced when the yarn conveying speed is increased.
The cause of this is that the tension of the yarn added to the direction changing guide becomes excessive, particularly when the yarn has a large diameter, and the force of binding the single yarns inside the yarn to each other increases, and the yarn becomes dense. In some cases, the cleaning liquid became difficult to penetrate into the yarn.

Japanese Patent Application Laid-Open No. 5-140815 discloses a so-called ladder roll on a bath tub, which stimulates the conveyed yarn to improve the washing efficiency and at the same time suppress the adhesion between single yarns. Techniques are disclosed. According to this, with a large-diameter or high-density yarn, when the yarn conveying speed increases, the cleaning effect tends to be insufficient.

[0012]

SUMMARY OF THE INVENTION It is an object of the present invention to improve the process passability during production even when the acrylic yarn to be spun has a large diameter, a high density, and a high speed at which the yarn is conveyed. An object of the present invention is to provide a method for producing an acrylic fiber, which is excellent, and from which a high-quality acrylic fiber can be obtained, and an apparatus for washing an acrylic yarn in a bath.

[0013]

To achieve the above object, the present invention has the following arrangement. That is, the acrylic polymer solution is spun into yarn, then guided into a bath, and adhered to the yarn while being continuously conveyed by a roll having a member that supports the yarn on the outer periphery. This is a method for producing acrylic fibers by washing and removing the solvent that has been washed and further turning the washed yarn into fibers by a treatment including drawing.

Further, in order to achieve the above object, the present invention has the following configuration. That is, an in-bath cleaning apparatus including a bath for holding a cleaning liquid and a plurality of rolls immersed in the cleaning liquid, wherein at least one of the plurality of rolls is provided.
One is an apparatus for washing acrylic yarn in a bath, which is a roll having a member for supporting the yarn on the outer peripheral portion.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION In the production of acrylic fiber, the present inventors have a member for supporting a yarn on an outer peripheral portion in washing and removing a solvent attached to a yarn after spinning in a bath. While continuously transporting the yarn with the roll, the solvent adhering to the yarn is washed and removed, and the yarn after the washing is converted into a fiber by a process including drawing, whereby the above-described problem is solved. And arrived at the present invention.

In general, when washing a large-diameter, high-density yarn, it is difficult for the washing liquid to sufficiently penetrate into the inside of the yarn, a sufficient washing effect is not obtained, and the single yarn is conveyed on a transport roll. The two fibers are pressed together to cause adhesion between single yarns, so that the process passability is deteriorated and the quality of the obtained fiber is often deteriorated. However, according to the present invention, a sufficient washing efficiency and an effect of suppressing adhesion between single yarns were obtained.

In the present invention, the acrylic polymer preferably has an acrylonitrile content of 90% by weight or more and a monomer copolymerizable with acrylonitrile of 10% by weight or less. Examples of the copolymerizable monomer include acrylic acid, methacrylic acid, itaconic acid and their methyl esters, propyl esters, butyl esters, alkali metal salts, ammonium salts, allylsulfonic acid, methallylsulfonic acid, styrenesulfonic acid, and these. At least one selected from the group consisting of alkali metal salts of

The acrylic polymer is obtained by a polymerization method such as emulsion polymerization, bulk polymerization, or solution polymerization. From the obtained polymer, dimethylacetamide, dimethylsulfoxide (hereinafter abbreviated as DMSO), dimethylformamide, nitric acid, An acrylic fiber can be obtained by preparing a polymer solution using a rodin soda washing solution or the like as a solvent, spinning the solution by a wet spinning method, a dry-wet spinning method, or the like, and passing through other steps.

The present invention can be preferably applied to any yarn spun from the acrylic polymer as described above, but in particular, the carbon fiber is used as a precursor for obtaining carbon fiber. The effect of the present invention is remarkable in terms of the process passability to be performed and the quality of the obtained carbon fiber, so that it can be preferably applied.

According to the present invention, in the yarn spun from the acrylic polymer, the lower limit of the number of constituent single yarns is 300.
0, preferably 6,000, and the upper limit of the number of constituent single yarns is 20,000, preferably 15,000, more preferably 12,000, and still more preferably 10,000.
In the case of a book, the effect of the present invention is remarkable and is preferable.

Further, in the present invention, the lower limit of the total fineness of the obtained acrylic fiber is 3000 denier, preferably 6000 denier, and the upper limit of the total fineness is 210 denier.
00 denier, preferably 16,000 denier, more preferably 13,000 denier, even more preferably 100 denier
In the case of a large diameter of 00 denier, the effect of the present invention is particularly remarkable and is preferable.

The yarn has a yarn density index M defined by the following equation of 2000 to 5000, preferably 25.
The case of 00 to 5000 is preferable because the effect is further enhanced. M = (total denier per thread [d (d: denier)]) / (thread width [mm]) In the present invention, a roll having a member for supporting a thread (hereinafter simply referred to as a support portion). 2 is shown in FIG. FIG. 2 shows an example in which the support portion has a columnar shape. In addition, an elliptic column having an elliptical cross section or a polygonal column having a polygonal cross section can be preferably used as the support portion.

In the roll having the support portion, it is preferable that the support portions are arranged at substantially equal intervals on the outer peripheral portion of the roll in parallel with the roll axis. Further, it is preferable that the number of the supporting portions is arranged on the outer peripheral portion of 6 to 24 per roll. When the number is 5 or less, the frequency of vibrating the yarn decreases, and the effect of penetrating the cleaning liquid into the yarn decreases. When the number is 25 or more, the amplitude of the vibration applied to the yarn decreases, In each case, the cleaning efficiency may be insufficient.

As shown in FIG. 2, when the supporting portion has a cylindrical shape, the distance a (cm) between the center of the roll and the supporting portion on the roll and the radius b (cm) of the cross section of the supporting portion are equal to each other. ,Relational expression:
It is preferable to satisfy 5 × b <a <20 × b. 5 × b ≧
If a, the contact time of the yarn with respect to one support portion is prolonged, and the effect of suppressing the adhesion between single yarns may be insufficient. If a ≧ 20 × b, the vibration applied to the yarn may be insufficient. And the cleaning efficiency may be insufficient. In addition,
When an elliptic cylinder or a polygonal prism is used as the support, when a portion where the yarn to be transported contacts the support is approximated by an arc, the radius of curvature is b ′ (cm), and the relational expression is:
It is preferable to satisfy 5 × b ′ <a <20 × b ′.

Also, in the present invention, the acrylic polymer solution is spun into yarn, then guided into a bath, and conveyed by a plurality of rolls immersed in a cleaning solution to form the yarn. In washing and removing the attached solvent, the effect of the present invention can be obtained as long as at least one of the plurality of rolls has a support portion on the outer peripheral portion. Roll, immersed in
At least one of the rolls immersed in the cleaning liquid, which is a draw roll on the outlet side of the bathtub, is a roll having a support portion on the outer peripheral portion, which increases the efficiency of washing and removing the solvent, and furthermore, is generated on the yarn. It is preferable from the viewpoint of more effectively suppressing the adhesion between single yarns.

Further, in the present invention, when the spun yarn is transported by a roll having a support portion on the outer peripheral portion,
The contact angle is preferably in the range of 30 to 90 °, preferably 30 to 60 °. If it is less than 30 °, the washing effect may be insufficient, and if it is more than 90 °, the conveying yarn may be pressed on the roller and adhesion between single yarns may occur.

[0027]

The present invention will be described below in detail with reference to examples. In the examples, the measurement and evaluation of the adhesion between single yarns, etc.,
The following method was used. The embodiment according to the present invention is not limited to the present embodiment. Table 1 summarizes the contents of each embodiment. (Adhesion between single yarns) Collect the yarn after washing, and use a single-edged razor for approx.
After cutting into mm, the mixture was dispersed and stirred (60 rpm × 1 minute) in a cleaning solution containing a nonionic surfactant. Thereafter, the dispersion was dispersed on a black filter paper, and the state of adhesion between single yarns was evaluated relative to each other on a five-point scale.

Here, the state where no inter-single yarn adhesion was observed was defined as class 1, and the state where most single yarns were adhered was defined as class 5, and the evaluation was made in five stages from class 1 to class 5. (Amount of Fluff Generation) After steam stretching, the conveyed yarn was visually observed for 5 minutes, and the number of fluff generated per minute per yarn (pieces / minute / filament) was counted. (Remaining amount of solvent [remaining amount of DMSO in the yarn]) The washed yarn from the bath was collected, boiled in distilled water at 100 ° C for 1.5 hours, and methyl acetoacetate was added for 1 hour. After mixing at a ratio of 1: 1, evaluation was made by gas chromatography. (Example 1) Acrylonitrile (hereinafter abbreviated as AN) 9
A DMSO solution composed of 9.5 mol% and 0.5 mol% of itaconic acid and containing 20% by weight of an AN copolymer having an intrinsic viscosity [η] of 1.8 was used as a spinning dope solution. Was spun into a coagulation bath composed of a washing liquid containing, to obtain a coagulated yarn having 12,000 single yarns.

[0029] The obtained coagulated yarn (processed yarn) is processed to have a yarn width of 40, 50, 70 mm and a yarn density of 3000, 2 respectively.
As shown in FIG. 1, the yarn 3 to be treated is guided into the bathtub 1 by the feed roll 4 on the entrance side of the bathtub, and has a supporting portion on the outer periphery, as shown in FIG. The solvent (DMSO) adhered to the yarn was removed by washing with a washing liquid 2 (here, an aqueous solution) while the inside of the bath was transported by the roll 6 and the draw roll 5. Thereafter, drawing steps in a bath, application of an oil agent, drying and densification, and a drawing step in steam under pressure were performed to obtain an acrylic fiber having a total single denier of 1.0 denier and a total denier of 12,000 denier.

Here, a roll 6 having a supporting portion on the outer peripheral portion
Used were 18 cylinders with a radius of 10 mm, and a body with a radius of 120 mm, which was arranged on the outer periphery at substantially equal intervals in parallel with the roll axis. Here, the contact angle between the transport yarn and the roll 6 was set to 45 °.

The washed yarn was sampled, and the adhesion between single yarns of the yarn was measured by the above-described method. Table 1 shows the results. As shown in Table 1, the quality of the obtained yarn was very good at all levels. (Comparative Example 1) An acrylic fiber was obtained in the same manner as in Example 1 except that a roll having a support portion on the outer peripheral portion was not used as a roll provided in a bathtub so as to be immersed in the cleaning liquid.
Here, in the same manner as in Example 1, the adhesion between single yarns of the yarn was measured. As shown in Table 1, the quality of the obtained yarn was slightly poor at any level. (Example 2) The spun yarn was guided to the bath 1 under the conditions of a yarn width of 50 mm and a yarn density of 2400 d / mm, and washed.
Further, the roll 6 having a support portion on the outer peripheral portion has a radius of 1
8, 16, and 20 0 mm cylinders are arranged at substantially equal intervals on the outer periphery in parallel with the roll axis.
Acrylic fiber was obtained in the same manner as in Example 1 except that a fiber having a diameter of 1 mm was used. Here, as in the first embodiment,
The adhesion between single yarns of the yarn was measured. As shown in Table 1, the quality of the obtained yarn was good at all levels. (Example 3) Rolls 6 each having a support portion on the outer peripheral portion were made up of 5, 25 cylinders each having a radius of 10 mm and arranged on the outer peripheral portion at substantially equal intervals in parallel with the roll axis.
An acrylic fiber was obtained in the same manner as in Example 2 except that m was used. Here, in the same manner as in Example 1, the adhesion between single yarns of the yarn was measured. As compared with Example 2, the washing efficiency of the yarn was slightly lowered, but the quality of the obtained yarn was good at all levels as shown in Table 1. (Example 4) A roll 6 having a support portion on an outer peripheral portion is provided with 18 cylindrical columns having radii of 8, 15, and 22 mm, and the outer peripheral portion is arranged at substantially equal intervals in parallel with the roll axis. Is 1
An acrylic fiber was obtained in the same manner as in Example 1 except that the length was 20 mm. Here, as in the first embodiment,
The adhesion between single yarns of the yarn was measured. As shown in Table 1, the quality of the obtained yarn was good at all levels. (Example 5) A roll 6 having a support portion on the outer peripheral portion was provided with 18 cylinders having a radius of 5 and 25 mm, and the outer peripheral portion was arranged at substantially equal intervals in parallel with the roll axis.
An acrylic fiber was obtained in the same manner as in Example 1 except for using m. Here, in the same manner as in Example 1, the adhesion between single yarns of the yarn was measured. As shown in Table 1, the quality of the obtained yarn was good at all levels. (Example 6) An acrylic fiber was obtained in the same manner as in Example 1 except that a roll having a support portion on the outer peripheral portion was also used as a roll immersed in a bathtub among draw rolls 5 on the outlet side of the bathtub. Was. Here, in the same manner as in Example 1, the adhesion between single yarns of the yarn was measured. As shown in Table 1, the quality of the obtained yarn was good at all levels. (Example 7) In the same manner as in Example 1 except that the contact angle between the roll 6 having the support portion on the outer peripheral portion and the transport yarn was set to each value of 20, 30, 60, 90, and 100 °, An acrylic fiber was obtained. As the contact angle was increased, the washing efficiency of the yarn was improved, but the yarn was pressed by the roller and the fluff increased due to the adhesion between the single yarns. Here, as in the first embodiment,
The adhesion between single yarns of the yarn was measured. As shown in Table 1, the quality of the obtained yarn was good at all levels.

[0032]

[Table 1]

[0033]

According to the method for producing an acrylic fiber of the present invention, the washing efficiency after spinning the yarn is greatly improved, and the adhesion between the single yarns due to the compression of the yarn on the roll is effectively suppressed. It is possible to greatly stabilize the spinning process and obtain an acrylic fiber which becomes a high-quality carbon fiber after firing.

In addition, according to the acrylic yarn in-bath washing apparatus of the present invention, when a large-diameter and high-density yarn is washed, it is difficult for the cleaning liquid to sufficiently penetrate into the inside of the yarn. Despite the fact that it is difficult to obtain a good cleaning effect, the single yarns are pressed against each other on the transport rolls and adhesion between the single yarns occurs, and the quality of the obtained fiber is often deteriorated as the process passability is deteriorated, Sufficient cleaning efficiency and the effect of suppressing adhesion between single yarns can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a bath cleaning apparatus.

FIG. 2 is a schematic view showing an example of a roll having a support portion on an outer peripheral portion.

[Explanation of symbols]

 1: Bath tub 2: Cleaning liquid (aqueous solution) 3: Yarn to be treated 4: Feed roll (entrance roll) 5: Draw roll 6: Roll having a support on the outer periphery

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hidemi Goto 1515 Tsutsui, Matsumae-cho, Iyo-gun, Ehime Pref. BA48 DA34 DB02

Claims (7)

[Claims] An acrylic polymer solution is spun to form a yarn, then guided into a bath, and the yarn is continuously conveyed by a roll having a member for supporting the yarn on the outer periphery. A method for producing an acrylic fiber, in which a solvent adhering to a fiber is washed and removed, and the washed fiber is converted into a fiber by a treatment including drawing. 2. The acrylic fiber according to claim 1, wherein the yarn has a yarn density index M defined by the following formula of 2,000 to 5,000, and the number of single yarns constituting the yarn is 3,000 to 20,000. Manufacturing method. M = (total denier per thread [d (d: denier)]) / (thread width [mm]) 3. The number of single yarns constituting the yarn is 3,000 to 3,000.
The method for producing acrylic fibers according to claim 2, wherein the number is 10,000. 4. An in-bath cleaning apparatus comprising a bath for holding a cleaning liquid and a plurality of rolls immersed in the cleaning liquid, wherein at least one of the plurality of rolls has a thread on an outer peripheral portion. A device for washing acrylic yarn in a bath, which is a roll having a supporting member. 5. The acrylic yarn bath according to claim 4, wherein said members are arranged at substantially equal intervals on the outer periphery of the roll, and the number of said members is 6 to 24 per roll. Medium washing device. 6. The member has a columnar shape, and a distance a (cm) between a center of the roll and the center of the member and a radius b (cm) of a cross section of the member are represented by a relational expression of 5 × b. The apparatus for cleaning acrylic yarn in a bath according to claim 4 or 5, wherein <a <20xb is satisfied. 7. A contact angle between a roll having a member for supporting a yarn on the outer peripheral portion and the yarn conveyed in a bathtub is 30 to 9;
The apparatus for cleaning acrylic yarn in a bath according to any one of claims 4 to 6, wherein the angle is within a range of 0 °.