JPH0333801B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to a method for producing melt-spun fibers having a small single filament denier of 1.5 denier or less and a low strength of 3.5 g/de or less. <Prior art> Traditionally, the production of small single denier yarns has been
It is known that the process is poor and extremely difficult. In particular, in addition to the spinning process conditions, yarn breakage and roller winding are likely to occur during the drawing process, which is the biggest problem. Moreover, when it comes to low-strength yarn, yarn breakage and roller winding are more likely to occur, and the difficulty of manufacturing is doubled.
It has been virtually impossible to stably industrially produce fibers with a g/de or less. For this reason, conventional methods for manufacturing small single-filament denier yarns have focused on manufacturing techniques that do not require a drawing process, and have adopted high-speed spinning techniques (spinning speeds of 3,000 m/min or higher).
That is, high-speed spinning + fine denier + rapid cooling promotes oriented crystallization in the spinning process, producing fibers with an elongation of 40% or less without drawing. However, in conventional methods, when the single yarn denier is 0.6 denier or more, especially around 1 denier, oriented crystallization does not proceed sufficiently during the spinning process, resulting in an excessively high elongation of the product, which results in problems with the fully drawn yarn. It cannot be used as a normal product thread. Furthermore, in high-speed spinning methods that do not involve a drawing process, it is difficult to adjust the strength and elongation of the product yarn, heat shrinkage rate, etc. in the spinning conditions. There is a problem. In addition, as mentioned above, the most technically difficult point in producing yarn with a small single yarn denier and low strength is the occurrence of yarn breakage and roller winding during the drawing process, and overcoming this point is the biggest challenge. The focus is on technical considerations. As a solution to this problem, the present inventor's proposal is to perform interlacing treatment on the single yarns before drawing, so that each single yarn is not treated individually.
The idea was to increase the apparent thickness and yarn tenacity of the single yarns by causing them to behave in groups, thereby preventing single yarns from breaking during the drawing process and from being wrapped around the drawing roller. However, under commonly used conditions, if the single yarn is subjected to interlacing treatment before drawing and then stretched, unstretched areas will occur, resulting in so-called thick and
Thin yarn is manufactured. This is clear from the fact that the method of drawing after the interlacing treatment is known as a method for producing thick and thin yarns. Purpose and Structure of the Invention The present inventor has made a proposal after intensively studying a method for entangling single yarns that does not generate undrawn yarns.
Increase the yarn to 0.5 g/de or more, and measure the intertwining strength of the yarn after stretching to make it 3 strands/m or more and 10 strands/m or less, and stretch it immediately without winding it up (direct spinning drawing). As a result, the present invention was achieved by discovering that there is no generation of undrawn yarns and the process is stable (no stretched yarn breakage or roller winding). That is, in the present invention, after melt-spinning, the first roller (take-up roller) The tension between the oil applying device and the first roller is set to 0.5 g/de or more, and a fluid entanglement process is performed between the two, and the degree of entanglement is measured on the stretched yarn. This is a method for melt-spinning polyester, characterized in that the spinning speed is at least /m and at most 10 /m. In the present invention, when the tension is less than 0.5 g/de, the generation of undrawn yarn cannot be prevented if the interlacing treatment is performed to the extent that there is no drawn yarn breakage or roller winding. It was found that undrawn yarn does not occur when the tension is 0.5 g/de or more, but although the cause of this has not been clarified, it is estimated as follows from observation of the entangled state of the yarn after the entangling treatment. . That is, when the entanglement treatment is performed under low tension, strong entanglement occurs locally, resulting in a so-called tangle-like form as shown in FIG. On the other hand, when the entanglement process is performed under high tension, the entanglement becomes long and loose as shown in Figure 2. However, it is presumed that unstretching does not occur in the latter case. In addition, the degree of entanglement that does not cause stretch yarn breakage or roller wrapping is 3 cases/m or more when measured with the yarn after stretching, and 10
The suitable value is less than 10 strands/m; if it exceeds 10 strands/m, unstretched yarn will occur even if the tension of the thread is increased during the intertwining process.
If it is less than x/m, the entangling effect will be small, and stretching and breakage and roller wrapping will occur. Furthermore, if the undrawn yarn that has been subjected to the interlacing treatment is wound up and then stretched,
Compared to the case where the yarn is immediately stretched without being wound up, the number of yarn breakage and roller winding increases. The cause of this is not clear, but the form of entanglement in the method of the present invention is vastly different from the usual form of entanglement.
Since the fibers are not so-called "chip-like" but long and loosely tangled, it is thought that if left for a long time, the fibers will shrink and the tangles will become weaker. In any case, the combination of three factors: performing appropriate entanglement treatment before drawing, increasing the tension at that time, and drawing immediately without winding after spinning, resulted in a single yarn denier of 1.5 denier or less. This made it possible to stably produce yarn with a low strength of less than 3.5 g/d. Here, various methods can be considered to increase the tension during the entangling process, that is, the tension between the oil application device and the first roller. ),
Particularly effective are methods such as increasing the diameter of the spinneret hole, that is, increasing the spinning draft rate (150 or more, preferably 180 or more), and strengthening cooling (shortening the distance under the spinneret, increasing the cooling air velocity, etc.). Further, the entanglement treatment device is not particularly limited, and a fluid entanglement treatment device such as an interlace nozzle or a false twist nozzle using ordinary air can be used. The key point in the method of the present invention is to perform an interlacing treatment before stretching, but in order to improve handling in the subsequent process, an additional entangling treatment may be performed after the stretching roller and before winding up. However, in this case, it goes without saying that the degree of entanglement applied immediately before winding must not be taken into consideration when measuring the degree of entanglement applied before stretching in order to improve stretchability. The method of the present invention can be applied to all fibers manufactured by melt spinning, such as polyester and polyamide, but it is especially applicable to fibers produced by melt spinning, such as polyester and polyamide. The effect is remarkable for polyester fibers used as units. Further, a third component may be copolymerized or mixed with these fibers. In particular, in the case of polyethylene terephthalate fibers consisting of a terephthalic acid component and an ethylene glycol component, the strength decreases significantly when metal sulfonate groups are contained. A fiber having an intrinsic viscosity of 3.5 g/d or less and satisfying the range of the present invention can be obtained. The degree of entanglement was measured by a conventional method using a commercially available entanglement tester (manufactured by Rothsield). Measurements were made for 40 entangled pieces, and the degree of entanglement was
It is expressed by counting the number of pieces per 1m. Next, the present invention will be explained with reference to the drawings. FIG. 3 is an explanatory diagram of steps suitable for carrying out the method of the present invention. In the figure, 1 is a spinning tube, 2 is a running thread, 3 is an oil agent application device, 4 is a fluid entanglement treatment device, 5 is a first roller (take-up roller), 6 is a second roller (drawing roller), and 7 is a It is a winding device. The method of the present invention includes an oil applying device 3 and a first roller 5.
The tension of the yarn is set to 0.5 g/d or more between the yarn and the yarn is subjected to a fluid entanglement treatment, and the yarn is continuously stretched between the first roller 5 and the second roller 6 without being wound up. be. Effects of the Invention As described above, according to the method of the present invention, yarns with a small single yarn denier and low strength can be processed in good process condition, that is, without drawing breakage or roller winding, and without generating undrawn yarns. It becomes possible to stably produce yarn of good quality. Next, the method of the present invention will be further explained using examples. Example 1 A polyester containing ethylene terephthalate as the main repeating unit and a 5-sodium sulfoisophthalic acid component copolymerized at 2.6 mol% based on the total acid component was made into 72 pieces using the spinning/drawing apparatus shown in Figure 3. Melt is discharged from a nozzle with holes, speed of 1800m/
It is pulled out in minutes and immediately stretched to 2.1 times without being rolled up, resulting in a product with a fineness of 75 denier and a single fiber count.
A product yarn with a denier of 1.04 and a strength of 3.0 g/d was obtained.
The spinning tension at this time is the value measured between the oil application device and the first roller, and depends on the cooling conditions and spinneret hole diameter (spinning draft rate).The degree of fluid entanglement is the value measured on the yarn after drawing, and depends on the supply fluid pressure. By changing each, the results shown in the table below (Table 1) were obtained. For comparison, a test was also conducted in which the yarn was wound up once after spinning and then stretched two days later (Level No. 6).

【table】

[Table] Here, the stretching breakage rate and roller winding rate are 1doff5
The occurrence rate is calculated based on production volume per 1 ton of kg, 20% or less is defective, and 10% or less is good. In addition, the occurrence of unstretchedness was determined by dyeing the knitted fabric. Example 2 A polyester containing ethylene terephthalate as the main repeating unit and a 5-sodium sulfoisophthalic acid component copolymerized in an amount of 3.5 mol% based on the total acid component was made into 48 pieces using the spinning/drawing apparatus shown in Figure 3. Melted and discharged from a nozzle with holes, the product fineness is 50 denier, the single yarn fineness is 1.04 denier, and the strength is 2.
A product yarn of ~2.5 g/d was obtained. At this time, the speed of the take-off roller (spinning speed), the speed ratio of the take-off roller and the stretching roller (stretching ratio), and the spinning draft ratio, that is, the diameter of the spinneret were variously changed, and the results shown in the table below (Table 2) were obtained. Here, the spinning tension is the value measured between the oil agent applying device and the first roller as in Example 1, and
The degree of fluid entanglement was measured on the yarn after drawing, and was adjusted by changing the supply fluid pressure.

【table】

[Table] Here, the stretching yarn breakage rate, roller winding rate, and occurrence of unstretched yarn were determined by the same method as in Example 1. From the above results, it can be understood that the method of the present invention has a small single yarn denier and is suitable for producing low strength yarns.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the form of entanglement when fluid entanglement treatment is performed under low spinning tension, and FIG. 2 is a diagram showing the form of entanglement when fluid entanglement treatment is performed under high tension according to the method of the present invention. FIG. 3 is an explanatory diagram of a melt spinning winding process suitable for carrying out the present invention. 1 is a spinning tube, 2 is a yarn, 3 is an oil application device, 4
5 is a fluid entanglement processing device, 5 is a first roller (take-up roller), 6 is a second roller (stretching roller), 7
is a winding device.

Claims (1)

[Claims] 1. After melt spinning, the fiber is drawn without being wound up, and the single fiber fineness is 1.5 denier or less and the strength is
When producing polyester fibers of 3.5 g/de or less, an oil agent is applied in front of the first roller (take-up roller), the tension between the oil agent application device and the first roller is set to 0.5 g/de or more, and during this time 1. A method for melt spinning polyester, which comprises subjecting the yarn to a fluid entanglement treatment, and measuring the degree of entanglement of the drawn yarn to be 3 strands/m or more and 10 strands/m or less. 2. The polyester melt spinning method according to claim 1, wherein the take-up speed of the first roller is 1600 m/min or more. 3 Patent scope 1 where the spinning draft is 150 or more
A method for melt spinning polyester according to item 1 or 2. 4 Melt-spun fibers contain ethylene terephthalate as the main repeating component and metal sulfonate groups.
A method for melt-spinning a polyester according to the patent scope item 1, 2 or 3, which is polyethylene terephthalate containing 1.5 to 4.5 mol%.