JP2013177707A - Method for producing synthetic fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing ultrafine synthetic fibers having a single fiber fineness of 1.5 dtex or less by melt spinning, which can suppress variations in 15% stress and can suppress variations due to nonuniformity in dyeing among filament groups each including multiple filaments in the same spinneret.SOLUTION: In a method for producing synthetic fibers, a thermoplastic resin is melted, and filament groups extruded from a spinneret 2 in an annular arrangement are annularly cooled with cooling air blown out from the outer circumferential side of the filament groups toward the center side of the filament groups using an annular cooling device 5 provided below the spinneret. The filament groups are run in a spinning chimney 62, and an oil solution is applied to them. The method for producing synthetic fibers satisfies the following conditions (A) to (C) at the same time: (A) the spinning chimney is provided below the annular cooling device; (B) an oil solution-applying device 7 is present in the spinning chimney or below the spinning chimney; and (C) the filament groups are surrounded by the spinning chimney over the entire circumference.

Description

  The present invention relates to a method for producing a synthetic fiber.

  In recent years, since it has a soft and excellent texture, it can be used as a raw material for synthetic leather, high-density fabrics, luxury clothing, etc., for example, production of synthetic fibers composed of ultrafine fibers with a single yarn fineness of 1.5 dtex or less A method is required. However, as the synthetic fibers become extremely fine (single yarn finer), the physical properties of the original yarn vary, specifically fineness spots and cross-sectional spots (hereinafter collectively referred to as “Worster spots”), high elongation (Hereinafter referred to as “toughness”) Due to variations, there is a tendency for quality deterioration and quality differences to occur for high-order products such as thin fabrics. It is.

  On the other hand, to improve productivity, speeding up by increasing the winding speed of the spinning and increasing efficiency by winding multiple yarns (multi-threading) in the same spinneret are important considerations from the viewpoint of cost reduction. It is also an issue.

  For this reason, the present inventors have proposed Patent Document 1, and for Wooster spot variation, each filament group discharged from the spinneret is moved from the outer peripheral side to the center side using an annular cooling device provided directly below the spinneret. For the annular cooling with cooling air blown out toward the toughness variation, in addition to making the filament group temperature as low as possible when applying the oil agent, each filament group discharged from the spinneret on the vertical downstream line, The oil solution was applied in an orthogonal or substantially orthogonal direction in the same direction, and the problem was solved.

  In Patent Document 2, it is proposed that an annular cooling device is provided directly below the spinneret via a delay cooling means using a heater, and a means for sucking an air flow is provided in the device and its spinning cylinder. This not only improves the flow of cooling air between filaments, reduces yarn swinging and suppresses Worcester spots, but also suppresses variation in orientation between single fibers by actively discharging high-temperature airflow. It is a technique to do.

JP 2010-196219 A Japanese Patent Laid-Open No. 2000-212824

  However, in the invention described in Patent Document 1, there is an effect of suppressing Wooster spots and toughness variation, and there is no problem in terms of quality in the woven or knitted raw machine, but depending on the dyed color to be developed in the fabric after dyeing, Higher quality problems such as streak-like or sink-like dark spots remained. As a result of pursuing the cause of these shading spots, it was found that this was uneven dyeing among the filament groups in the same spinneret. In particular, in the dyeing of polyamide fibers, since the dye is coordinated to the non-crystalline part of the fiber, the development of a production method that uniformly controls the non-crystalline part between each filament group is used to suppress dyeing variation. Is indispensable.

  For this reason, as a result of diligent investigation, the dyeing difference variation has a correlation with the tensile strength at 15% elongation (hereinafter referred to as “15% stress”), which is one index of raw yarn physical properties. In addition, since the accelerating airflow caused by the annular cooling device and the descending airflow caused by the accompanying airflow of the running filament are not uniformly applied between the filament groups, a spinning tension difference appears between the filament groups, that is, the filament groups increase. It has been found that as the number of yarns progresses and the fineness of the single yarn becomes finer, 15% stress variation tends to occur and dyeing difference variation occurs. Therefore, suppression of 15% stress variation is a problem with respect to Patent Document 1.

  Further, in the method described in Patent Document 2, with respect to the intake cylinder provided at the center of the spinning cylinder, for example, if the inner diameter of the spinneret, delay cooling means, and annular cooling means is large, the intake cylinder can be installed. However, when the inner diameter is small, there is a concern that the filament discharged from the spinneret may come into contact with the intake cylinder and thread breakage may occur frequently. However, it is not only difficult to adjust the balance between the annular cooling device and the descending air flow rate of the filament and the intake air amount from the intake cylinder because the entrained air flow rate is small in the fine-fine varieties. Further, there is a possibility that the intake air amount is reduced due to clogging with oligomers or the like, and it takes time and effort to perform spinning while finely adjusting the balance.

  In view of the above-described points, the present invention has a single yarn fineness of 1. to suppress the 15% stress variation of each filament group composed of multiple yarns in the same spinneret and to suppress the dyeing difference variation. It is an object of the present invention to provide a method for producing an ultrafine synthetic fiber of 5 dtex or less by melt spinning.

The synthetic fiber manufacturing method of the present invention that achieves the above-described object has the following configuration.
(1) Melting the thermoplastic resin and discharging each filament group discharged from the spinneret annularly from the outer peripheral side of each filament group using an annular cooling device provided at the lower part of the spinneret Is a manufacturing method in which annular cooling is performed by cooling air blown toward the center side of the nozzle, the filament groups are run in a spinning cylinder, and an oil agent is applied, which simultaneously satisfy the following conditions (A) to (C): A method for producing a synthetic fiber.
(A) A spinning cylinder is provided below the annular cooling device.
(B) An oil agent applying device exists in the spinning cylinder or under the spinning cylinder.
(C) The filament groups are all wrapped around the spinning cylinder.

In the method for producing a synthetic fiber of the present invention, more specifically, preferably, any one of the following configurations (2) to (7) is used.
(2) The method for producing a synthetic fiber according to (1) above, further satisfying one or more of the following conditions (D) and (E):
(D) The spinneret, the annular cooling device, and the axis of the spinning cylinder are aligned on the vertical downstream line.
(E) Each filament group discharged annularly from the spinneret is a multifilament group having three or more yarns. (3) The vertical length of the spinning cylinder is 1800 mm or less ( The manufacturing method of the synthetic fiber as described in 1) or (2).
(4) The method for producing a synthetic fiber according to any one of (1) to (3), wherein the following conditions (F) to (I) are satisfied at the same time.
(F) The spinneret has a plurality of discharge holes, and the discharge holes are annular in one row or arranged concentrically in a plurality of rows.
(G) The said arrangement | sequence is divided | segmented by the division band for dividing for every filament group.
(H) The filament discharged from the discharge hole becomes a multifilament on the vertical downstream line from an arbitrary point in the region (filament group) including the discharge hole in the divided array, and each group has an oil agent. To be granted.
(I) The filament group is applied with an oil agent orthogonally or substantially orthogonally to the vertical downstream line in the same direction.
(5) The method for producing a synthetic fiber according to any one of (1) to (4) above, wherein the single yarn fineness of each filament group is 1.5 dtex or less.
(6) The method for producing a synthetic fiber according to any one of (1) to (5), wherein the thermoplastic resin is polyamide.
(7) The method for producing a synthetic fiber according to any one of (1) to (6) above, wherein the cross-sectional shape of the fiber is irregular or hollow.

  According to the present invention, for each filament group discharged from the same spinneret, the annular cooling device and the descending airflow generated from the traveling filament group are uniformly applied to each filament group, and the production efficiency by multi-threading is achieved. In addition, it is possible to obtain an ultrafine synthetic fiber having a single yarn fineness of 1.5 dtex or less with a good quality with a small 15% stress variation and a small dyeing variation.

FIG. 1 is a schematic model perspective view showing an embodiment of a production apparatus preferably used in the synthetic fiber production method of the present invention, and in particular, showing a portion up to a spinning tube portion. FIG. 2 is a schematic process diagram showing one embodiment of a production apparatus preferably used in the synthetic fiber production method of the present invention. FIG. 3 is a schematic model diagram showing an embodiment of a spinneret that is preferably used in the method for producing a synthetic fiber of the present invention. FIG. 3A is an outline of five yarn groups (filament groups) in two annular rows. FIG. 3 (b) is a schematic top model view showing five yarn groups (filament groups) in an annular row. FIG. 4 shows one embodiment of a production apparatus preferably used in the method for producing a synthetic fiber of the present invention, and is a schematic cross-sectional model diagram showing a spinneret and an annular cooling device in particular. FIG. 5 is a schematic top model diagram showing the positional relationship between the cross-sectional shape of the spinning cylinder and the yarn group of the spinneret preferably used in the method for producing a synthetic fiber of the present invention, and FIG. FIG. 5B is a model diagram showing six yarn groups in a hexagonal cross section. FIG. 6 is a schematic model diagram showing an embodiment in the case where there is a gap slit in the spinning cylinder cross-sectional shape preferably used in the synthetic fiber manufacturing method of the present invention, and FIG. FIG. 6B is a cross-sectional model view showing the positional relationship in the case of a four-thread group, and FIG. 6B is a side model perspective view showing a part up to the spinning tube portion. FIG. 6 (c) is a cross-sectional model diagram showing the positional relationship when the spinning cylinder has a hexagonal cross section and a six-thread group, and FIG. 6 (d) is a side model perspective view particularly showing a part up to the oil application device. is there. FIG. 7 shows one embodiment of a production apparatus preferably used in the synthetic fiber production method of the present invention, and in particular, the positional relationship between the spinning cylinder wall surface and the cooling air blowing cylinder of the annular cooling device and the oil agent application device. FIG. FIG. 8 shows one embodiment of a production apparatus preferably used in the synthetic fiber production method of the present invention, and in particular, the axis of a spinning cylinder (round section) and the axis of a spinneret (six yarn group). It is a schematic upper surface model figure which shows a mutual positional relationship when a core and the axial core of an annular cooling device do not correspond. FIG. 9 shows one embodiment of a production apparatus preferably used in the synthetic fiber production method of the present invention, and in particular, the shaft core of a spinning cylinder (quadratic cross section) and the spinneret (four yarn group). It is a schematic top model diagram showing the mutual positional relationship when the shaft core and the shaft core of the annular cooling device are coincident. FIG. 10 shows one embodiment of a production apparatus preferably used in the synthetic fiber production method of the present invention, and in particular, an outline showing the length in the vertical downstream line direction of the section from the spinneret to the oil agent application apparatus. It is a side model perspective view. FIG. 11 shows an embodiment of a production apparatus used in a conventional synthetic fiber production method, and is a schematic model perspective view showing a spinning cylinder portion in particular.

  Hereinafter, the present invention will be described in more detail. 1 and 2 show an embodiment of the synthetic fiber manufacturing apparatus of the present invention. In particular, FIG. 1 is a schematic model perspective view showing a portion up to a spinning tube portion, and FIG. 2 is a schematic process drawing. is there. FIG. 3 is a schematic model diagram showing an embodiment of a spinneret that is preferably used in the method for producing a synthetic fiber of the present invention, and FIG. 3 (a) is an annular two-row five-thread group (filament group). FIG. 3B is a schematic top model diagram showing five yarn groups (filament groups) in an annular row. FIG. 4 shows one embodiment of a production apparatus preferably used in the method for producing a synthetic fiber of the present invention, and is a schematic cross-sectional model diagram showing a spinneret and an annular cooling device in particular.

  In the present invention, the molten thermoplastic resin is finally extruded from the discharge hole 20 provided in the spinneret 2 to form a filament or a filament group.

  Here, as shown in FIGS. 3A and 3B, the discharge holes 20 are preferably arranged in a plurality of rows and one row in a concentric circle. In the case of a plurality of rows, the arrangement positions of the discharge holes 20 forming the inner annular row are in relation to the arrangement positions of the discharge holes forming the annular row on the outer side of the annular row. Is preferably arranged so that no other discharge hole exists on the line connecting the center of the discharge hole and the center of the spinneret. Further, the spinneret 2 is divided by a separation band 21 for dividing each yarn, and the total number of divided groups and the number of filament groups in the divided group area (inside the dotted frame) 22 are the same. The total number of discharge holes arranged inside is the number of single yarns (filament number) of each filament group. Specifically, FIGS. 3A and 3B are each divided into five to form five filament groups (five yarns / spinneret) per spinneret, and FIG. Filament, FIG. 3 (b) shows 8 filaments.

  As shown in FIG. 4, each filament group discharged from the spinneret 2 in this way is used to suppress contamination with time of the spinneret 2, so that the gas in the path for blowing steam from the gas supply port 3 in the gas supply device 4 is used. The filament groups are cooled and solidified by the annular cooling device 5 that blows the cooling rectified air A from the outer peripheral side toward the center side through the supply zone S. The vertical distance LS from the lower surface of the spinneret to the upper end of the cooling air blowing portion of the annular cooling device 5 is preferably in the range of 10 to 100 mm from the viewpoint of suppressing yarn swings and fineness spots, and is preferably 30 to 65 mm. More preferred. With respect to the cooling air speed blown from the cooling air blowing tube, the average value of the section from the upper end surface to the lower end surface of the cooling blowing tube is in the range of 0.05 to 1.0 (m / sec) and the Wooster value and toughness. From the viewpoint of value and yarn-making property.

  As shown in FIGS. 1 and 2, a spinning cylinder 62 is provided at the lower part of the annular cooling device 5 so as to surround the filament groups on the entire circumference. An oil agent applying device 7 for applying an oil agent to the filament is provided. In the present invention, the spinning cylinder is provided in order to level the contact of the accelerated air blown from the annular cooling device and the descending airflow flowing from the yarn accompanying the filament group.

  As shown in FIG. 11, the spinning cylinder in the prior art is generally as shown in FIG. 11, and the spinning cylinder 61 has a viewpoint of ease of threading to the oiling section and yarn separation work and ease of confirmation of filament running during spinning. Therefore, a part of the spinning cylinder 61 is open and does not wrinkle all around.

  However, in the spinning cylinder 61 having the open portion as described above, the descending air flow in which the accelerating air blown from the annular cooling device 5 and the accompanying air flow generated from the running filament itself is released to the open portion side, that is, the atmospheric side. The diffusion of the air flow in the spinning cylinder drifts, and as a result, the 15% stress in the running direction of each filament group becomes non-uniform. In the present invention, in order to avoid this, a spinning cylinder 62 is provided so as to surround each traveling filament group all around.

  As shown in FIG. 1, the cross-sectional shape of the spinning cylinder 62 is most preferably a round cross-section that matches the annular arrangement shape of the discharge holes 20 of the spinneret 2, but the shaft core C described later is the spinneret 2 and the annular cooling device 5. As long as both the spinning cylinders 62 are matched, a square cross section may be used. For example, as shown in FIGS. 5 (a) and 5 (b), a cross section corresponding to the number of filament groups of the spinneret 2, for example, a quadrilateral group is a square. The cross section may be a polygonal cross section such as a hexagonal cross section if it is a 6-divided group. Although it is desirable to make the n-divided group a regular n-square or a substantially regular n-square in terms of increasing the uniformity of the downflow airflow to each filament, the yarn is within a range that does not significantly impair the uniformity of the downflow airflow. The number of stripes and the number of vertices of the polygon may be different. Further, the spinning cylinder 62 surrounds the entire circumference of each filament group, and covering the entire surface is desirable in terms of improving the uniformity of the direction of the downdraft to each filament, but it is not necessary to cover all the surfaces. It suffices to surround the filaments so that the descending airflow to each filament is as similar as possible, and a perforated portion such as a slit may be provided on the side surface of the spinning cylinder. Preferably, as shown in FIGS. 6 (a) to 6 (d), the shape may be such that the gap slits 63 are provided on each side surface from the position of the vertical downstream line direction distance L1 from the base lower surface position, not only the slit, It is only necessary to uniformly open holes such as punching. The number of slits, slit width W, and length L2 with respect to one surface of each spinning cylinder are not particularly defined, and the form of perforation such as slits on each side has substantially the same shape so that the descending airflow received by each filament is the same. Is preferred.

  Here, FIG. 5 is a schematic top model diagram showing the positional relationship between the cross-sectional shape of the spinning cylinder and the yarn group of the spinneret that is preferably used in the method for producing a synthetic fiber of the present invention, and FIG. FIG. 5B is a model diagram showing a six-thread group in a hexagonal cross section. FIG. 6 is a schematic model diagram showing an embodiment in the case where there is a gap slit in the spinning cylinder cross-sectional shape preferably used in the synthetic fiber manufacturing method of the present invention, and FIG. FIG. 6B is a cross-sectional model view showing the positional relationship in the case of a four-thread group, and FIG. 6B is a side model perspective view showing a part up to the spinning tube portion. FIG. 6C is a cross-sectional model diagram showing a positional relationship when the spinning cylinder has a hexagonal cross section and a six-thread group, and FIG. 6D is a side model perspective view particularly showing a part up to the oil application device. FIG.

  FIG. 7 shows one embodiment of a production apparatus preferably used in the synthetic fiber production method of the present invention, and in particular, the positional relationship between the spinning cylinder wall surface and the cooling air blowing cylinder of the annular cooling device and the oil agent. FIG. 8 is a schematic top model view showing an applying device, and FIG. 8 shows an embodiment of a manufacturing device preferably used in the method for manufacturing a synthetic fiber of the present invention, and in particular, an axis of a spinning cylinder (round section). FIG. 3 is a schematic top model diagram showing the mutual positional relationship when the axis of the spinneret (six yarn group) and the axis of the annular cooling device do not match.

  As shown in FIGS. 5 (a), 5 (b), 7, and 8, the shaft core C is each vertical passing through the center of the cross section of the spinneret 2, the annular cooling device 5, and the spinning cylinder 62. Lines in the downstream line direction (C1, C2, C3), more preferably, the spinneret 2, the annular cooling device 5, and the axis of the main spinning cylinder 62 are matched. As a result, the descending airflow is imparted in a uniform manner by the traveling filament group, and the 15% stress variation of each filament group is suppressed. If the axis C1 of the spinneret 2 and the axis C2 of the annular cooling device 5 do not match, the yarn Y pushed out from the discharge hole 20 according to the degree of deviation and the inner wall surface of the cooling air blowing cylinder 50 Since the distance P of the air fluctuates depending on the location, it becomes difficult for the cooling rectified air A to be sprayed uniformly on each filament, so that the Worcester spots of each filament group tend to deteriorate. If it deviates, depending on the degree of the deviation, as described above, it becomes difficult for the descending airflow to be imparted to each traveling filament group in a balanced manner, and there is a tendency for a 15% stress variation to occur.

  The vertical length L of the spinning cylinder is preferably up to 1800 (mm), more preferably 300 to 1500 (mm), although it depends on the filament fineness. On the other hand, if it exceeds 1800 (mm), the yarn swaying of the running yarn becomes large due to the influence of the descending air flow, and it becomes difficult to make the 15% stress variation uniform. Among them, when the spinning tube length L is in the range of 300 to 1500 (mm), the fiber structure of the filament is sufficiently formed, and the variation of 15% stress is suppressed, and a good quality is obtained. The spinning cylinder is preferably installed between the lower part of the annular cooling device and 1800 mm in the downstream direction, and the upper end of the spinning cylinder is most preferably provided directly below the annular cooling apparatus.

  The oil agent applying device 7 provided in the inside of the spinning cylinder 62 and in the lower part thereof is provided at a position where the oil agent is applied from the respective divided group areas 22 of the spinneret 2 to the vertical downstream line at right angles or substantially at right angles in the same direction. Preferably there is. For example, as shown in FIG. 7, there are four oil supply nozzles 71 in the case of a four-divided group (four yarns / spinneret). As a result, the pitch P between the inner wall surface of the cooling air blowing tube 50 of the annular cooling device 5 and the traveling filament group can be the same or substantially the same in each group, and more uniform cooling can be achieved to improve Wooster spots. Is expected. The distance P is preferably 5 to 20 (mm), more preferably 7.5 (mm) to 15 (mm).

  The position of the oil application device 7, that is, the vertical distance Lg from the lower surface of the spinneret in FIG. 10 to the position of the oil supply nozzle 71 of the oil application device depends on the single yarn fineness and the cooling efficiency of the filament from the annular cooling device 5. 400 to 3000 (mm) is preferable, and 600 to 1800 (mm) is more preferable. When it is 400 (mm) or more, the filament temperature is lowered to an appropriate level when the oil agent is applied, and when it is 3000 (mm) or less, the yarn swaying due to the downdraft is small, and fibers with very small Worcester spots are obtained.

  The synthetic fiber production method of the present invention is more effective when the filament group discharged from the spinneret 2 is wound by a winder with a single yarn fineness of 1.5 dtex or less. Demonstrated. More preferably, it is a case of an ultrafine synthetic fiber having a single yarn fineness of 1.0 dtex or less, more preferably 0.5 to 0.8 dtex. The number of single yarns per yarn is preferably 36 filaments or less, more preferably 12 to 30 filaments. The effect of the present invention is remarkably exhibited when the total number of divided areas per spinneret, that is, the total number of yarns, is 3 or more. More preferably, it is 4 yarns to 8 yarns. Exceeding 8 yarns may cause restrictions on the design of the size of the spinneret 2 and the pitch between the discharge holes in the base, or equipment restrictions such as a winder.

  By adopting such a configuration, a synthetic fiber having practical raw yarn properties can be manufactured by the most rational process. When the filament group Y discharged from the spinneret 2 is wound by the winder 8, the winding speed is 3000 (m / min) or more, preferably 4000 (m / min) or more, 5000 (m / min). ) Taking up as described below is preferable in terms of cost and stable production because it enables higher speeds in addition to making multiple yarns.

  The synthetic fiber production method of the present invention can be preferably applied to a production method of thermoplastic fibers such as polyamide fiber, polyester fiber, and polypropylene fiber. More preferably, it is the manufacturing method of the thermoplastic fiber for clothes. Furthermore, the effects of the present invention are more remarkably exhibited in the case of polyamide fibers. Although it does not specifically limit as a polyamide fiber, Nylon 56, nylon 6 fiber, nylon 66, nylon 610, nylon 612 fiber is preferable. In addition to these functional additives such as moisture absorption, antibacterial properties, and matting, these fibers may also be used for yarn production, such as anti-coloring agents, stabilizers, heat-resistant agents, and the like, as long as the objects and effects of the present invention are not impaired. You may give additives, such as a property improvement.

  In the method for producing a synthetic fiber according to the present invention, the production efficiency is improved in multi-thread take-up, and the production method has good quality with small variations in 15% stress and dyeing difference between yarns, and good operability. Can be provided. The same effect can be obtained not only when manufacturing yarns made of ordinary round cross-section fibers but also when manufacturing fiber yarns made of irregular cross-section fibers. Here, the irregular cross-section fiber has, for example, a non-circular cross section such as a Y-shaped or T-shaped, C-shaped, flat-shaped cross section, or a hollow cross section.

  EXAMPLES Hereinafter, although an Example is given and the manufacturing method of the synthetic fiber of this invention is demonstrated more concretely, this invention is not limited to these Examples. In addition, the measuring method of each characteristic value in an Example and a comparative example was judged with the following method.

[Evaluation of 15% stress variation]
For each multifilament in the same spinneret obtained by the production method of the present invention, the 15% stress value was measured five times by the following measurement method, and the average value (Xn) was calculated. Thereafter, an average value (X) and a standard deviation (σ) between the multifilament groups in the same spinneret were calculated. The standard deviation is calculated from unbiased variance. Then, CV (%) was calculated from the relational expression of CV (%) = σ / X × 100 (%), and the variation was evaluated in three stages.
A: “Excellent” (CV (%) = 0 to less than 2.00%)
○: “Good” (CV (%) = 2.00 to less than 4.00%)
×: “Inferior” (CV (%) = 4.00% or more)

[Measurement of 15% stress]
Regarding the measurement of the 15% stress value of each multifilament (for one yarn) in the same spinneret obtained by the production method of the present invention, the tensile force is applied in accordance with JIS L1013 (2010) 8.5.1. When measuring strength and elongation (elongation), a tensile strength-elongation curve was drawn, and the tensile strength (cN) at 15% elongation was 15% stress. In addition, as a measurement condition, a constant-speed tension type testing machine (Tensilon manufactured by Orientec Co., Ltd.) was used, the grip interval was 50 (cm), and the tensile speed was 50 (cm / min). The average value (Xn) is calculated five times.

[Evaluation of variation in dyeing difference]
[Production of tube knitted fabric]
In the target varieties, the same yarn is divided and wound so that the tube yarn is about 78 dtex in terms of the total fineness (2 for 33 dtex, 4 for 17 dtex, 7 for 11 dtex) And knitted fabric is produced by arranging the knitted fabrics in parallel for each filament group in the same spinneret so that the knitting density is 50 (books / inch (2.54 cm)). did.

[Scouring and dyeing tube knitted fabric]
Thereafter, 100 (ml) of a nonionic surfactant (“Neugen” SS, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 0.1 (g / l) aqueous solution was prepared as 100 (ml) for the knitted fabric 1 (g). At 15 ° C. for 15 minutes, then with running water for 20 minutes, and dehydrated with a dehydrator. Next, the dye concentration of the gold-containing dye (BASF Palatin Fast Black) was adjusted to an L value of 40 ± 2 and dyed at a temperature of 90 (° C.) for 15 minutes.

[Measurement of variation in dyeing difference]
Using a colorimeter (SM-P manufactured by Suga Test Instruments Co., Ltd.), the L value for each filament group was measured for the main dyed tube knitted fabric, and the variation (R (− )) Was calculated. From this calculation result, variation evaluation was performed in three stages, and ○ or more was regarded as acceptable. In addition, L value was made into the average value of L value measured repeatedly 3 times within the center part (3 cm x 3 cm) for each filament group.
A: “Excellent” (R (−) = 0 to less than 0.50)
○: “Good” (R (−) = 0.50 to less than 1.00%)
X: “Inferior” (R (−) = 1.00% or more).

[Comprehensive evaluation]
As a comprehensive evaluation, based on the evaluation results of 15% stress variation (CV (%) 15) and dyeing difference variation (R (-)), the result of comprehensive evaluation is the one with the lower evaluation in any of the above results. Adopted as.
A: “Adoptable and excellent”
○: “Recruitment is possible”
×: “Inferior, not available”

(Examples 1-2, Comparative Example 1)
In the apparatus mode shown in FIGS. 1 and 2, as shown in FIGS. 7 and 10, the discharge hole arrangement is two annular rows, the divided group area 22 is four groups (four yarns / spinneret), and 33 dtex 26 Presence / absence of an open part of a spinning cylinder (round section) provided at the lower part of the annular cooling device 5 for multi-filaments of filaments (when present: spinning cylinder is all-around saddle type 62, none: spinning with one side open) The cylinder 61) was evaluated. However, the vertical length (L) of the spinning cylinder is evaluated with two types of 600 (mm) and 800 (mm) so that the oil agent applying device exists in the spinning cylinder and under the spinning cylinder.

  As specific conditions, a polymer of nylon 6 (25 ° C., tip of 98% sulfuric acid relative viscosity 2.8, melting temperature 280 ° C.) is melted, and the polymer is discharged from the spinneret 2 shown in FIG. 4 through a gas supply zone S (vertical distance Ls from the lower surface of the spinneret to the cooling air blowing cylinder in the annular cooling device is 50 (mm)) through the nozzle from the annular direction. Sprayed uniformly on the bottom surface, cooling air blowing speed (average wind speed in the section where La is 300 (mm) from the top face of the cooling blowing cylinder) is 0.6 (m / s), each filament group and cooling wind blowing cylinder The filament Y is cooled by the annular cooling device 5 having a distance (P) of 7.5 (mm) from the center so that it is substantially orthogonal to the vertical downstream line direction from an arbitrary position of each divided group area 22 of the spinneret 2. The bottom surface of the spinneret 2 The oil supply device 7 in which each of the oil supply nozzles 71 is arranged at a position where Lg is 1000 (mm) is installed to perform the interlacing process, the winding speed at the winder 10 is set to 4500 (m / min), and the evaluation is performed. Carried out. The 98% sulfuric acid relative viscosity and the single yarn fineness were measured by the following methods.

[98% sulfuric acid relative viscosity]
(A) A sample is weighed and dissolved in 98% by weight concentrated sulfuric acid so that the sample concentration (C) is 1 g / 100 ml.
(B) The solution (a) is measured for the number of seconds (T1) dropped at 25 ° C. using an Ostwald viscometer.
(C) The falling seconds (T2) at 25 ° C. of 98 wt% concentrated sulfuric acid in which the sample is not dissolved are measured in the same manner as in the item (2).
(D) The 98% sulfuric acid relative viscosity (ηr) of the sample is calculated by the following equation. The measurement temperature is 25 ° C.
(Ηr) = (T1 / T2) + {1.891 × (1.000−C)}.

[Single yarn fineness]
In the embodiment shown in FIG. 2, each filament group is wound up by the winder 10, measured according to 8.3.1 of JIS L1013 (2010), and a value obtained by dividing the fineness by the number of filaments. Single yarn fineness (dtex) was used.

  As can be seen from Table 1, the nylon 6 fiber produced by wrapping all the filament groups with a spinning cylinder (Examples 1 and 2) had a remarkable effect of suppressing 15% stress variation and dyeing variation variation. Further, the nylon 6 fiber produced (Example 2) with a spinning tube length of 800 mm so that the oil agent applying device was present in the spinning tube was particularly excellent.

(Examples 3 to 4, Comparative Example 2)
1 and FIG. 2, as shown in FIG. 8 and FIG. 10, the discharge hole arrangement is an annular row, the divided group area 22 is 6 groups (6 yarns / spinneret), and 17 dtex 12 filaments. Evaluation of the eccentricity of the axial center position of the spinning cylinder 62 (round cross section) provided at the lower part of the annular cooling device 5 was carried out using the multifilament of No. 1 as an object type. In this evaluation, the spinneret 2 and the axial cores C1 and C2 of the annular cooling device 5 are matched, and the axial core C3 of the spinning cylinder 62 is provided at a position eccentric from the core by 20 (mm) in the radial direction. It was. The procedure was the same as in Example 1 except for a special comment.

  As specific conditions, a polymer of nylon 66 (25 ° C., tip of 98% sulfuric acid relative viscosity 2.8, melting temperature 280 ° C.) is melted, and the polymer is discharged from the spinneret 2 as shown in FIG. Using the apparatus 4, the spinneret 2 is supplied via the gas supply zone S (the vertical distance Ls from the lower surface of the spinneret to the cooling air blowing cylinder in the annular cooling device is 35 (mm)) by the injection port from the annular direction. The cooling air blowing speed (average wind speed in the section where La is 250 (mm) from the top surface of the cooling blowing cylinder) is 0.45 (m / s), between each filament group and the cooling wind blowing cylinder. The filament Y is cooled by the annular cooling device 5 having a distance (P) of 7.5 mm, and spinning is performed so as to be substantially orthogonal to the vertical downstream line direction from an arbitrary position of each divided group area 22 of the spinneret 2. Base 2 The oil application device 7 in which the oil supply nozzles 71 are arranged at positions where Lg is 800 (mm) from the lower surface position is provided and entangled, and the winding speed at the winder 10 is set to 4000 (m / min). Carried out. However, the vertical length (L) of the spinning cylinder 62 is 300 (mm), and the oil agent applying device is present under the spinning cylinder.

  As can be seen from Table 2, the nylon 66 fiber produced by spinning each filament group with a spinning cylinder (Examples 3 and 4) had a remarkable effect of suppressing 15% stress variation and dyeing variation variation. Further, the nylon 66 fiber manufactured (Example 4) in which the spinneret, the annular cooling device, and the shaft cores C1, C2, and C3 of the spinning cylinder coincide with each other was further excellent.

(Examples 5 to 9)
1 and FIG. 2, as shown in FIGS. 6 (c) and 6 (d), the discharge hole array is in an annular row and the divided group area 22 is in 6 groups (6 yarns / spinning). The vertical length (L), gap slit position (L1), and slit length (L2) of the spinning cylinder 62 were evaluated using a multifilament of 11 dtex12 filaments as a target variety. In this evaluation, the slit width (W) was set to 20 (mm). The procedure was the same as in Example 1 except for a special comment.

  As specific conditions, a polymer of nylon 6 (25 ° C., tip of 98% sulfuric acid relative viscosity 2.8, melting temperature 280 ° C.) was melted, and the polymer was discharged from the spinneret 2 as shown in FIG. Using the apparatus 4, the spinneret 2 is supplied via the gas supply zone S (the vertical distance Ls from the lower surface of the spinneret to the cooling air blowing tube in the annular cooling device is 30 (mm)) by the injection port from the annular direction. The cooling air blow speed (average wind speed in the section where La is 200 mm from the cooling blow pipe upper end surface) is 0.45 (m / s), and between each filament group and the cooling wind blow pipe The filament Y is cooled by the annular cooling device 5 having a distance (P) of 7.5 mm, and spinning is performed so as to be substantially orthogonal to the vertical downstream line direction from an arbitrary position of each divided group area 22 of the spinneret 2. Of base 2 An oil application device 7 in which oil supply nozzles 71 are arranged at positions where Lg is 600 (mm) from the surface position is provided and entangled, and the winding speed at the winder 10 is set to 4000 (m / min). Carried out. However, the above-described shaft cores C1, C2, and C3 are evaluated by matching.

  As can be seen from Table 3, if the shape of the side surface of the spinning cylinder is the same, the length L of the spinning cylinder is 300 mm (Examples 5 and 8), 500 mm (Example 9), regardless of the shape of the gap slit, Nylon 6 fiber produced as 1500 mm (Example 6) was particularly excellent.

1: Synthetic fiber manufacturing device 2: Spinneret 20: Discharge hole 21: Separation zone 22: Divided group area 3: Gas supply port 4: Gas ejection device 5: Annular cooling device 50: Cooling air blowing cylinder 61: Spinning cylinder ( Partially open)
62: Spinning cylinder (whole go)
63: gap slit 7: oil supply device 71: oil supply nozzle 8: winder Y: yarn S: gas supply zone A: cooling rectification air P: distance between yarn Y and cooling air blowing tube L: spinning tube Vertical length La: Vertical distance Ls of the cooling air blowing tube Ls: Vertical distance Lg from the lower surface of the spinneret to the leading end position of the cooling air blowing tube in the annular cooling device From the lower surface of the spinning nozzle to the oil supply nozzle position of the oil supply device Vertical distance L1: gap slit start position length L2: gap slit length W: gap slit width C1: cross-sectional center of spinneret C2: cross-sectional center of annular cooling device C3: cross-sectional center of spinning cylinder

Claims (7)

Each filament group melted from the thermoplastic resin and discharged in an annular shape from the spinneret is moved from the outer peripheral side of each filament group to the center side of each filament group using an annular cooling device provided at the lower part of the spinneret. Is a manufacturing method in which annular cooling is performed by cooling air blown toward the surface, the filament groups are run in a spinning cylinder, and an oil agent is applied, which simultaneously satisfy the following conditions (A) to (C): A method for producing synthetic fibers.
(A) A spinning cylinder is provided below the annular cooling device.
(B) An oil agent applying device exists in the spinning cylinder or under the spinning cylinder.
(C) The filament groups are all wrapped around the spinning cylinder. Each filament group melted from the thermoplastic resin and discharged in an annular shape from the spinneret is moved from the outer peripheral side of each filament group to the center side of each filament group using an annular cooling device provided at the lower part of the spinneret. In which the filament group is run in a spinning cylinder and oil is applied to satisfy the following conditions (D) and (E): The manufacturing method of the synthetic fiber of Claim 1 characterized by the above-mentioned.
(D) The spinneret, the annular cooling device, and the axis of the spinning cylinder are aligned on the vertical downstream line.
(E) Each group of filaments discharged annularly from the above spinneret is a multifilament group of three or more yarns. Each filament group melted from the thermoplastic resin and discharged in an annular shape from the spinneret is moved from the outer peripheral side of each filament group to the center side of each filament group using an annular cooling device provided at the lower part of the spinneret. In which the filament group is run in the spinning cylinder, and the filaments are run in the spinning cylinder to apply the oil. The vertical length of the spinning cylinder is 1800 mm or less. The manufacturing method of the synthetic fiber of Claim 1 or Claim 2. Each filament group melted from the thermoplastic resin and discharged in an annular shape from the spinneret is moved from the outer peripheral side of each filament group to the center side of each filament group using an annular cooling device provided at the lower part of the spinneret. Is a manufacturing method in which annular cooling is performed with cooling air blown toward the surface, each filament group is run in a spinning cylinder, and an oil agent is applied, and the following conditions (F) to (I) are satisfied simultaneously: The manufacturing method of the synthetic fiber in any one of Claims 1-3.
(F) The spinneret has a plurality of discharge holes, and the discharge holes are annular in one row or arranged concentrically in a plurality of rows.
(G) The said arrangement | sequence is divided | segmented by the division band for dividing for every filament group.
(H) The filament discharged from the discharge hole becomes a multifilament on the vertical downstream line from an arbitrary point in the region (filament group) including the discharge hole in the divided array, and each group has an oil agent. To be granted.
(I) The filament group is applied with an oil agent orthogonally or substantially orthogonally to the vertical downstream line in the same direction. The method for producing a synthetic fiber according to any one of claims 1 to 4, wherein the single yarn fineness of each filament group is 1.5 dtex or less. The method for producing a synthetic fiber according to any one of claims 1 to 5, wherein the thermoplastic resin is polyamide. The method for producing a synthetic fiber according to any one of claims 1 to 6, wherein the cross-sectional shape of the fiber is irregular or hollow.

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