JPH05156509A - Method for treating yarn in bath - Google Patents

Abstract

PURPOSE:To improve both the permeation of a bath liquid into the interior of a yarn bundle and the washing efficiency, prevent single filaments from bonding and stabilize the process, etc., by jetting a bath liquid at a specific speed on yarn in the bath in carrying out treatment of the yarn in the bath such as washing with water or drawing. CONSTITUTION:Yarn is treated in a bath. In the process, a bath liquid is jetted from a position separate from the yarn in the bath at >=1 to <=50m/see speed on the yarn. Specifically, the bath liquid pressurized with a liquid supply pump 4 is jetted from a bath liquid jetter 3 on the yarn 1 running through treating rollers 2 and 2' in the treating bath in a bath vessel in which the bottom of the bath is divided with a perforated plate 8. Polyacrylonitrile-based yarn which is raw yarn for carbon fiber is preferred as the yarn. The number of filaments constituting the yarn is preferably 6000 from the viewpoint of improvement in productivity and the apparent size per yarn to be treated is preferably >=6000 denier.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating a yarn in a bath, more specifically, for example, washing of polyacrylonitrile fiber produced by a wet or dry-wet spinning method, drawing, or application of an oil agent. The method of treating in a bath.

[0002]

2. Description of the Related Art Polyacrylonitrile fiber is used as a raw yarn (precursor) of carbon fiber, and many techniques for improving polyacrylonitrile fiber have been disclosed in order to obtain carbon fiber having excellent performance. In recent years, regarding the use of carbon fiber, there is a strong demand for expansion of the application from the fields of aviation, space, or sports, which have been the main applications to the general industrial fields such as automobiles and building materials. In order to meet the demand for expansion of applications in the general industrial field, it is most important to reduce the manufacturing cost and provide inexpensive carbon fiber.

In order to reduce the manufacturing cost, the yarn to be treated in the bath is thickened (thickened) in order to improve the productivity of the facility, that is, to increase the production amount per unit facility. If the yarn width that the yarns occupy in the apparatus and the processing bath are narrowed (increased in density), the following problems occur. If the yarn unit is thickened or densified in the yarn making process, the solution permeability into the yarn becomes poor in the drawing process, the water washing process, or the process of applying the process oil agent, and adhesion between single yarns occurs. Or heat spots on the yarn,
Occurrence of fluff and yarn breakage, insufficient washing with water, and uneven adhesion of oil,
Process passability may be reduced. Also, in the subsequent firing step, yarn breakage and fluffing will occur, and the process passability will decrease, and the physical properties of the resulting carbon fiber will also decrease.

Regarding the yarn treatment in the bath, JP-A-57-4
In Japanese Patent No. 2917, the bath liquid is brought into a boiling state by a heating part intermittently installed at the lower part of the yarn, and the yarn is intermittently and repeatedly passed through the bath liquid in the boiling state.
Methods have been proposed to improve cleaning efficiency and energy efficiency. However, there is a problem in that the liquid upflow is small and a sufficient effect cannot be obtained unless it is in the boiling state, and conversely, the adhesion between single yarns is increased in the boiling state.

Further, Japanese Patent Laid-Open No. 61-108715 discloses that thread cleaning, drawing, and oil application are performed at 10 to 90 kHz.
Has been proposed under the irradiation of ultrasonic waves. However, thick yarns and high-density yarns are not sufficiently effective, and it is extremely difficult to uniformly irradiate ultrasonic waves to all yarns in a large-scale processing apparatus that can be mass-produced. It was poor in practicality. Further, in the step of applying the oil agent, there is a problem that the dispersed state of the oil agent is destroyed by the ultrasonic waves.

Japanese Unexamined Patent Publication Nos. 64-68559 and 6
In Japanese Patent Laid-Open No. 4-85305 and Japanese Patent Laid-Open No. 64-85306, washing water, an oil agent, and a bath liquid are jetted from a yarn direction change guide in a yarn washing step, an oil agent applying step, and a hot water drawing step. Accordingly, there has been proposed a method of improving the cleaning efficiency and the uniformity of application of the oil agent, and preventing fusion between single yarns. However, in the case of thick thread,
The tension of the yarn on the direction change guide becomes particularly large,
There is a problem that the single yarns inside the yarn bundle are mutually constrained, so that there is a problem that it is difficult for the bath liquid to permeate the inside of the yarn and the adhesion between the single yarns cannot be prevented. .. Moreover, sufficient stretching could not be performed, and a fiber having good physical properties could not be obtained. Further, the above method is to prevent the adhesion of the yarn by jetting water having a temperature lower than the temperature of the treatment bath solution by 5 to 30 ° C. from the yarn direction change guide to prevent the yarn from adhering. A temperature-controlled injection device must be provided in the process, which increases the manufacturing cost.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a thick process and a process with high yarn density without causing the above-mentioned problems and having excellent processability and uniform treatment. The object of the present invention is to provide a method for treating a yarn in a bath, which can be performed relatively easily.

[0008]

Means for Solving the Problems The above-mentioned object of the present invention is, in the treatment of a yarn in a bath, the speed of the bath liquid is 1 m / sec or more and 50 m / sec or less from a position apart from the yarn in the bath. Then, it can be achieved by a method for treating a yarn in a bath, which comprises spraying the yarn.

The method of the present invention can be applied to those in which a yarn is treated in a bath, but is suitable for producing a polyacrylonitrile-based yarn which is a raw yarn (precursor) of carbon fiber.

The bath liquid treatment in the present invention is a yarn treatment in a bath. For example, a washing process of a solvent, a drawing process in a bath liquid (bath drawing process), and a yarn process in an oil agent bath. An example is a refueling process in which an oil agent is applied by passing through.

In the present invention, the number of single yarns constituting the yarn is preferably 4000 filaments or more, and more preferably 6000 filaments or more from the viewpoint of improving equipment productivity. The apparent fineness D per yarn to be treated, which is calculated from the following formula, is preferably 4000 denier or more, and more preferably 6000 denier or more. D = n · d Here, n is the number of single yarns constituting one yarn to be treated in the bath, and d is the single yarn fineness [denier] of the finally obtained yarn (for example, precursor). is there.

The yarn density index M defined by the following formula is preferably 120 denier / mm or more because the effect of the present invention is great, and more preferably 150 denier / mm or more. M = D / w where w is the yarn width [mm] per yarn to be treated in the in-bath treatment step, and the yarn width occupied by one yarn to be treated on the roller used for the in-bath treatment Required from.

The feature of the present invention resides in that the bath liquid is jetted onto the yarn in the bath at a speed in a specific range. Hereinafter, the present invention will be described more specifically with reference to the drawings. FIG. 1 is a model diagram showing an embodiment of the yarn in-bath treatment according to the present invention. The bath liquid is jetted from the bath liquid jetting device 3 to the yarn 1 traveling in the treatment bath via the treatment rollers 2 and 2 ′, the bath liquid being pressurized by the liquid sending pump 4. It is done by that. The temperature of the bath liquid is kept constant by the temperature control device 5, and the injection amount of the bath liquid is controlled by the flow rate control device 6 and the flow meter 7. Partitioning the lower part of the bath with the perforated plate 8 is effectively and preferably used because it suppresses the disturbance caused by the action of sucking and discharging the bath liquid of the bath pump.

The injection speed is set to 1 m / min or more and 50 m / min or less. When it is lower than 1 m / min, the effect of the present invention due to the jetting liquid is difficult to appear, and when it is higher than 50 m / min, entanglement of yarns or breakage of single yarn occurs, which deteriorates processability and fiber physical properties. It is not preferable because it lowers. 2m /
More preferably, it is not less than minutes and not more than 40 m / min.

The position of the jet nozzle for jetting the bath liquid is in the same bath as the yarn. When the bath liquid is sprayed into the bath from the outside of the bath, air enters the bath together with the sprayed bath liquid, causing disturbance of the bath liquid and vibrating the yarn more than necessary. It is not preferable because it causes disorder and yarn breakage.

Further, the positional relationship between the injection nozzle and the yarn is not preferable because the movement of the yarn is suppressed when the yarn is in contact with the yarn as in the above-mentioned direction changing guide, and the effect of the present invention is reduced. .. Therefore, the distance between the jet nozzle and the yarn is preferably 1 mm or more and 100 mm or less.
If it exceeds 100 mm, the action due to the injection is reduced, which is not preferable. It is more preferable if it is 2 mm or more and 80 mm or less.

On the other hand, in the treatment step of the present invention, particularly in the bath drawing step, it is more preferable to reduce the number of rollers involved, because it is possible to avoid the adhesion between single yarns, which may occur due to the pressure applied to the drawing roller due to the drawing tension. When processing with multiple baths, it is possible to make the stretching tension uniform by adopting a non-driving method (free rotation method) for the rollers between the baths rather than a general driving method. It is preferable because the effect of the drawing method in the bath of the present invention can be more remarkably obtained. Further, it is also effective to vibrate the treated yarn at a frequency of about 5 to 100 Hz, and by combining these methods, it is possible to more effectively prevent the adhesion between single yarns in the bath drawing step, which is preferable. ..

The installation position of the jet nozzle is not particularly limited as long as the above-mentioned requirements are satisfied, but as an example, the constraint point of the yarn existing in the bath (for example, a yarn gripping roller, a yarn In the middle of the road regulation guide, etc., it is set at a position where the amplitude of the minute vibration of the yarn generated by the action of the jetted liquid becomes maximum.

In the present invention, polyacrylonitrile for producing carbon fiber which can be preferably used is as follows:
There is no particular limitation as long as it contains a monomer that promotes the flameproofing reaction. The spinning method is preferably a wet spinning method or a dry wet spinning method, but is not particularly limited.

[0020]

The present invention will be described in more detail with reference to the following examples. The characteristic values in the examples are obtained by the following method.

(1) Limiting draw ratio In the drawing process in the bath, the feeding speed (F) of the yarn to be treated is kept constant and the maximum speed (B) at which the yarn is cut when the take-up speed is increased. Is measured, and the numerical value obtained from the following formula is defined as the limit draw ratio. Limit draw ratio = B / F (2) Adhesion between single yarns The swollen yarns before applying the oil agent are cut into about 5 mm, dispersed in 0.1% by weight Neugen SS aqueous solution, and stirred with a stirrer at 60 rpm for 1 minute, and then black filter paper. The adhesive state was visually evaluated on a scale of 5 levels. The state in which no adhesion was observed was rated as class 1, and the state in which most of the single yarns were bonded was grade 5. When the grade is 4 or higher, problems such as impeding process passability and deteriorating the physical properties of carbon fiber occur. (3) Washability With water, the DMSO remaining in the yarn after washing with water is subjected to Soxhlet extraction, and this is quantified by gas chromatography to determine the amount of DMSO with respect to the weight of the dried yarn. did. The smaller the amount of DMSO, the better the water washability. (4) Adhesiveness of oil agent The state of adhesion between single yarns in the drying step was evaluated by the following method and used as an index of whether or not the oil agent is evenly adhered.
Except that the yarn to be evaluated is not the swollen yarn, but the yarn after the drying step, the single yarn-to-single yarn adhesion is determined in the same manner as in (2). It is evaluated that they are uniformly applied.

Examples 1 to 3 and Comparative Examples 1 to 3 Acrylonitrile (hereinafter abbreviated as AN) 99.5 mol% and itaconic acid 0.5 mol% AN copolymer having an intrinsic viscosity [η] of 1.80 A dimethyl sulfoxide (DMSO) solution containing 20% by weight of the coalescence was used as a spinning stock solution, and
From a 00H spinneret, it was spun into a coagulation bath consisting of DMSO and water to obtain 12000 coagulated yarns. The coagulated yarn was washed with water having a yarn width of 50 mm in a bath at 65 ° C., drawn in a hot water bath at 90 ° C., and applied with an oil agent in a bath at 25 ° C. with a roller for each treatment bath. Treatment was performed while jetting in the bath under the conditions shown in Table 1 from a jet nozzle installed in the bath at a position intermediate to the roller (Examples 1 to 1).
3). In addition, as a comparison of the in-bath injection effects, a in-bath treatment in which no in-bath injection was performed was also performed (Comparative Examples 1 to 3). Thereafter, the yarns were further subjected to steps such as dry densification, drawing under pressure steam and the like, and finally a raw yarn (precursor) having a single yarn fineness of 1 denier and a total fineness of 12,000 denier was obtained. (Yarn density index M =
This means that processing was performed under the condition of 12000/50 = 240 [d / mm]. ) Table 1 shows the bath liquid spraying conditions, the bath liquid spraying position, the limiting draw ratio, single yarn adhesion, water washability, and oil agent adhesion in each of the above steps.

[0023]

[Table 1]

When the bath liquid is sprayed and treated in the bath within the scope of the present invention (Examples 1 to 3), the adhesion between single yarns hardly occurs, the limit draw ratio is high, and the drawability in the bath is good. Recognize. Also, the water washability and the oil agent adhesion state were good. On the other hand, when the bath liquid is not jetted (Comparative Example 1),
When the bath liquid jetting speed is out of the range of the present invention (Comparative Example 2) and the bath liquid jetting position is not located away from the yarn (Comparative Example 3), single yarn-to-yarn bonding occurs, Further, it is understood that the limit draw ratio is low and the drawability in the bath is poor. In addition, the water washability and the state of adhesion of the oil agent were poor.

Examples 4 to 7 and Comparative Examples 4 to 7 Spinning was carried out in the same manner as in Example 1 except that the spinneret was 3,000 holes and the above-mentioned six spinnerets were used from a spinning spindle of 12 spindles. By changing the number of yarns to be processed in the process,
In addition, the yarn width is adjusted so that the yarn density is constant at 240 denier / mm, and the treated yarn fineness (thickness of the yarn) of the yarn is changed as shown in Table 2, and the single yarn in the drawing process in the bath The inter-adhesion was evaluated. The results are also shown in Table 2.

[0026]

[Table 2]

According to the method of the present invention (Examples 4 to 7),
It can be seen that the single yarn adhesion does not occur even when the treated yarn fineness increases and the yarn becomes thicker, and the drawability in the bath is good.

On the contrary, when the bath liquid is not jetted (Comparative Examples 4 to 7), it is found that the single yarn-to-yarn adhesion occurs when the treated yarn fineness increases and the yarn becomes thicker. Examples 8 to 13 and Comparative Examples 8 to 13 In the same drawing process in the bath as in Example 5 (treated yarn fineness 12000 denier), the yarn width was changed to obtain Table 3
The treated yarn density was changed as described above, and the adhesion between single yarns in the drawing process in the bath was evaluated. The results are also shown in Table 3.

[0029]

[Table 3]

According to the method of the present invention (Examples 8 to 1)
3) It can be seen that even if the treated yarn density is increased, single yarn adhesion does not occur and the drawability in the bath is good. On the other hand, when the jetting of the bath liquid is not performed (Comparative Examples 8 to 13), it is understood that the adhesion between single yarns occurs when the treated yarn density increases.

[0031]

EFFECTS OF THE INVENTION According to the method of the present invention, at a place where the binding force of the yarn is relatively small in the bath liquid, the bath liquid can be sprayed to enhance the permeability of the bath liquid to the inside of the yarn bundle for treatment.
Therefore, for example, in the washing step, there is an effect of improving the washing efficiency or the effect of preventing adhesion between single yarns, and in the bath drawing step, there is an effect of preventing the adhesion between single yarns or an effect of improving drawability due to uniform heating. In, there is an effect of uniformly applying the oil agent. In addition, even if there are single yarns that have already adhered to each other, there is a separating effect by jetting, so that process stability can be improved. Furthermore, even when treating thick yarns and high-density filament yarns in the bath, it is possible to perform uniform and stable treatment in the bath, which can dramatically improve the equipment productivity and achieve high quality and high performance. It becomes possible to manufacture carbon fiber at low cost, and its industrial effect is extremely large.

[Brief description of drawings]

FIG. 1 is a model diagram showing an example of a yarn in-bath treatment according to the present invention.

[Explanation of symbols]

 1: yarn 2, 2 ': processing roller 3: bath liquid jetting device 4: liquid feeding pump 5: temperature control device 6: flow rate control device 7: flow meter 8: perforated plate 9: bath liquid surface

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Okuda 1515 Tsutsui, Matsumae-cho, Iyo-gun, Ehime Toray Co., Ltd. Ehime Plant (72) Inventor Jun Yamazaki 1515 Tsutsui, Matsumae-cho, Iyo-gun, Ehime Toray Co., Ltd. Ehime factory

Claims (2)

[Claims] 1. In the in-bath treatment of a yarn, a bath liquid is sprayed onto the yarn from a position apart from the yarn in the bath at a speed of 1 m / sec or more and 50 m / sec or less. A method of treating the yarn in the bath. 2. The method for treating a yarn in a bath according to claim 1, wherein the yarn is a polyacrylonitrile fiber.