JPH0246701B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention alternately has convergent portions and non-convergent portions due to entanglement in the longitudinal direction of the yarn, and utilizes the difference in frictional properties between the convergent portion and non-convergent portion or the effect of convergence itself. The present invention relates to a method for producing a polyester multifilament yarn having uneven thickness or a difference in degree of dyeing in the longitudinal direction of the yarn by non-uniform stretching.

Conventionally, by drawing undrawn polyester yarn or semi-drawn yarn at an ambient temperature below the secondary transition point and at a draw ratio below the natural draw ratio, thickness unevenness of random length in the longitudinal direction of the yarn has been achieved. Alternatively, it is known to obtain multifilament yarns having different degrees of dyeing. However, it has the disadvantage that the uneven thickness or difference in degree of dyeing caused by such non-uniform stretching becomes uniform and does not stick out. Such uneven thickness or dyeing degree difference in the longitudinal direction of the thread becomes less constant as the number of single threads of the thread increases.

On the other hand, it is also known that undrawn or semi-drawn polyester yarns are intermittently drawn to obtain yarns that alternately have drawn portions and non-drawn portions in the fiber axis direction.

In this method, the single fibers constituting the yarn are not drawn individually at random, but as an aggregate as a yarn, so even if there are many single fibers, the thickness in the fiber axis direction The disadvantages of reduced unevenness or differences in dyeing intensity do not occur. However, since the effect of providing intermittent stretching is performed mechanically, unevenness in thickness or differences in dyeing degree appear regularly, resulting in poor commercial value.

The purpose of the present invention is to improve these drawbacks, and to provide satisfactory random thickness unevenness or dyeing degree difference in the longitudinal direction of the yarn even in multi-filament yarns with a large number of single yarns, and to Each of the thin portions is intended to provide a method for producing polyester multifilament yarn with little phase shift.

The structure of the present invention that achieves the above object is to rub a highly oriented undrawn yarn made of a polyester multifilament yarn that has been subjected to an interlacing treatment and has interlaced portions and unentangled portions alternately along the longitudinal direction of the yarn. This is a method for producing a polyester multi-filament yarn, which is characterized in that stretching is carried out at a stretching ratio equal to or lower than the natural stretching ratio while contacting the polyester yarn with the body.

The present invention will be explained in detail below.

FIG. 1 is a model illustration of an example of a highly oriented undrawn polyester yarn having entanglement before drawing according to the present invention. 2 indicates an unconfounded part.

When the above-mentioned yarn is brought into contact with another object, the unentangled portion 2 has a large number of single fibers in contact with the object, so the frictional force becomes significantly larger than that in the intertwined portion 1. In this way, the yarn has portions with a high friction coefficient and portions with a low coefficient of friction alternately in the longitudinal direction. Furthermore, since the degree of entanglement is high, the difference in friction coefficient is large.

In addition, compared to a yarn having no entanglement at all, the intertwined yarn described above naturally has higher cohesiveness, and the intertwined portion has particularly high cohesiveness. Therefore, deformation when subjected to an external force is more likely to occur as an aggregate than in the single fibers that make up the yarn.

Generally, by stretching highly oriented undrawn polyester yarn at a ratio equal to or lower than the natural stretching ratio of the yarn,
It is known that when obtaining a special yarn having uneven thickness or a difference in degree of dyeing in the longitudinal direction, dispersion between spindles can be reduced by providing a frictional resistor in the drawing zone. However, it has a drawback that the larger the number of single fibers constituting the thread, the smaller the uneven thickness in the longitudinal direction or the difference in degree of dyeing (phase shift occurs). This is because, as shown in Figure 2, the uneven thickness of each single fiber constituting the yarn or the difference in degree of dyeing between the lightly dyed portion 3 and the darkly dyed portion 4 have different phases within the yarn. It is. The effect of this phase shift is that the greater the number of single fibers, the higher the dispersibility, and the uneven thickness of the yarn or the difference in degree of dyeing is averaged out.

The present inventors paid attention to this point, and found that when a polyester highly oriented undrawn yarn with entanglement is used, in a drawing zone having a frictional resistor, when drawn at a ratio lower than the natural drawing ratio of the yarn, a surprising phenomenon occurs. In particular,
As shown in FIG. 3, a yarn is obtained in which the uneven thickness of each single fiber or the difference in degree of dyeing between the lightly dyed portion 3 and the darkly dyed portion 4 are almost in phase within the yarn. In other words, it is possible to obtain a yarn in which the thickness unevenness in the longitudinal direction and the difference in degree of dyeing are more pronounced. This is due to the high cohesiveness of the highly oriented undrawn polyester yarn, and the non-uniform stretching that occurs when the polyester yarn is drawn at a ratio lower than the natural drawing yarn ratio causes each single fiber constituting the yarn to This is because it occurs as a bundle of fibers rather than as a fiber.

Furthermore, due to the difference in surface friction properties in the longitudinal direction of the yarn caused by the interlaced and unentangled portions, sticks and slips occur between the yarn and the friction resistor in the drawing zone. The yarn is drawn as a bundle of fibers. Note that the greater the number of single fibers constituting the yarn, the more likely entanglement will occur, and the higher the stability of entanglement, so the above effect will be more pronounced.

In addition, by false-twisting yarns with little thickness unevenness or phase shift in dyeing degree difference in the longitudinal direction, it has crimps and a clearer difference in dyeing degree in the longitudinal direction. Needless to say, it is possible to obtain a spun-long processed yarn having the following characteristics.

The highly oriented undrawn yarn in the present invention has a birefringence index of
It is preferably in the range of 15 to 80×10 ⁻³ . In the case of extremely low-oriented undrawn polyester yarn with a birefringence ratio of less than 15×10 ^-3 , it is possible to obtain a high degree of entanglement by performing air treatment while spinning at a low speed. Yarns that have been subjected to non-uniform stretching have a lot of fuzz and are physically and chemically unstable.

The highly oriented unstretched material that has been subjected to the entanglement treatment needs to have entanglement stability against external forces, and it is desirable that the CF value, which also indicates the entanglement stability, be high, and it is more desirable that the CF value be 20 or more.

Here, the CF value is U.S. Patent No. 2985995 (1961,
This was measured using the "hook-and-drop method" described by DuPont.

On the other hand, the longer the thickness unevenness or the difference in dyeing degree in the longitudinal direction of the yarn, the more beautiful the heathered texture will be when made into a fabric. For this purpose, it is desirable that the average length of the interlaced portions, which determines the characteristics of the yarn aggregate, be longer than the average length of the unentangled portions.

In this way, due to non-uniform stretching at a natural stretching ratio or lower using highly oriented undrawn polyester yarn, the yarn has significant thickness unevenness or dyeing degree differences in the longitudinal direction, and most of these phase shifts are However, the heathered pattern of the knitted fabric formed by the average length of the dark dyed part 4 (thick part) or light dyed part 3 (thin part) is that the threads are intertwined. Affected by the average length of the convergence section (evaluated by water entanglement value).

The reason for this will be explained using FIG. 6. FIG. 6 shows the relationship between the average length of the convergent portion due to entanglement of highly oriented undrawn yarns and the roughness of the heathered pattern of the knitted fabric using the drawn yarn obtained therefrom. In Figure 6,
If the yarn bundle is long, the portion of the yarn bundle that slips on the friction resistor during stretching and is not stretched, that is, the high dyeing degree portion, becomes longer, resulting in a longer heathered pattern, resulting in a preferable marbled grain. You can feel it.

In order to give this kind of marbled heather feel,
The average length of the bundle of highly oriented undrawn yarns with entanglement is expressed as the water entanglement value, and the average length is 20
It is preferable that it is not less than mm.

Conversely, if the yarn convergence part is short, the highly dyed part will be short and the pattern will be fine. In particular, when the pattern is so fine as this, the knitted fabric becomes irritated and its commercial value is significantly inferior.

In the above, the "water entanglement value" refers to the length of the bundled part, excluding the opened part, when the yarn is floated on the surface of water at 20℃ with both ends free, and the 100 pieces of data of this bundled part are read. Find the average value for
This is displayed as a "water confounding value".

In this way, a highly oriented undrawn yarn with entanglement that yields a yarn with significant thickness unevenness and dyeing degree difference in the longitudinal direction of the yarn, almost no phase shift, and a preferable heathered pattern is shown in Figure 4, for example. Manufactured using equipment as shown. 5 is a drum around which highly oriented undrawn yarn is wound, 7 is a feed roller, 8 is an air entangling nozzle, 9 is a delivery roller, and 10 is a winding device.

In order to obtain a particularly high CF value, the diameter of the nozzle that imparts entanglement should be large (preferably 1
mm or more), and the supplied air pressure is preferably high (preferably 4 Kg/cm ² or more). The slower the processing speed, the better, preferably 500 m/min or less,
Not only the tension before and after the air entanglement nozzle, but also the maximum winding tension should be as low as possible (preferably
0.2g/d or less) is desirable.

On the other hand, in order to increase the average length of the intertwined condensed portion, for example, as shown in FIG. This can be obtained by guiding the person with a guide, etc. By doing this, the vibration frequency of the yarn in the yarn guide slit is lowered, and the time that the yarn is exposed to air when crossing the ejected airflow is increased, so that the convergence portion becomes longer.

As described above, the present invention makes it possible to provide a clearer and more beautiful heathered feel even when the number of single fibers constituting the yarn is large, and greatly contributes to expanding the product range.

Examples will be described below, but the present invention is not limited only to the examples.

Example: Denier 241D, number of single threads: 48, birefringence: 42x
10 ^-3 polyester multifilament yarn was subjected to air entanglement treatment using the apparatus shown in FIG. The air entanglement treatment conditions are as follows.

Processing speed: 200 m/min Nozzle type: Nozzle shown in Fig. 5 Air flow rate: 20 Nl/min Processing tension: 5 g/piece (between supply roller 7 and nozzle 8) Nozzle/slit inner thread path: Fig. 5, 12 Position winding tension: 10 g/number of winds: 10 winds/1 path The degree of entanglement of the obtained yarn was measured using the on-water entanglement value evaluation method.
It was 44.7mm.

On the other hand, when air entanglement was performed with the yarn passing through the center of the nozzle slit 13 shown in Fig. 5 as in normal entanglement, and other conditions were the same as above, no entanglement occurred. Although the number of converging parts increased and desirable results were obtained in terms of improvement in convergence, the average length of the convergent converging parts according to the evaluation method as water entanglement value was 7 mm.

The above-mentioned two types of highly oriented undrawn yarns were brought into contact with a pin-shaped friction body heated to about 65° C. and stretched at a stretching ratio equal to or lower than the natural stretching ratio. As a result of knitting the obtained yarn into a cylindrical shape, dyeing it, and comparing the marbling conditions, the former exhibited a relatively long pattern and beautiful marbling. On the other hand, the latter had a finer pattern.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing a model example of a highly oriented undrawn polyester yarn having entanglement before drawing according to the present invention, and Fig. 2 shows a pattern in which the light dyed area and the dark dyed area are out of phase. A schematic diagram of a yarn, Figure 3 is a schematic diagram of a yarn in which the phases of the light dyed part and the dark dyed part are almost the same, and Figure 4 is a schematic diagram of the yarn.
The figure is a schematic diagram showing one embodiment of a device for imparting entanglement to highly oriented undrawn polyester yarn, FIG. 5 is a sectional view showing an embodiment of an entanglement nozzle, and FIG. It is a graph showing the relationship between the average length and the roughness of the heathered pattern. 1: Confounded part, 2: Unconfounded part, 3: Lightly dyed part,
4: Dark dyeing section, 5: Drum, 6: Yarn, 7: Feed roller, 8: Air entangling nozzle, 10: Winding device, 11: Air spout, 12: Yarn.

Claims (1)

[Scope of Claims] 1. A highly oriented undrawn yarn made of polyester multifilament yarn subjected to an interlacing treatment in which entangled portions and non-entangled portions are alternately arranged along the longitudinal direction of the yarn while bringing it into contact with a friction body. A method for producing a polyester multifilament yarn, characterized in that stretching is carried out at a stretching ratio that is equal to or lower than a natural stretching ratio. 2. The method for producing a polyester multifilament yarn according to claim 1, wherein the highly oriented undrawn yarn has a birefringence of 15 to 80×10 ⁻³ . 3. The polyester multifilament yarn according to claim 1 or 2, characterized in that the average length of the converged portion due to entanglement that has been subjected to entanglement treatment is 20 mm or more expressed as a water entanglement value. Method of manufacturing strips. 4. The method for producing a polyester multifilament yarn according to claim 3, wherein the average length of the intertwined portions of the highly oriented undrawn yarn that has been subjected to the interlacing treatment is longer than the average length of the non-entangled portions. . 5. The method for producing a polyester multifilament yarn according to claim 1, wherein the entangling treatment of the highly oriented undrawn yarn is fluid entanglement. 6. The polyester according to claim 5, wherein the highly oriented undrawn yarn is subjected to fluid entanglement treatment by being guided by a guide so as to be pressed against the slit wall surface of the yarn path facing the air outlet of the fluid entanglement nozzle. Method for manufacturing multi-filament yarn. 7. The method for producing polyester multifilament yarn according to claim 5 or 6, wherein the yarn speed during fluid entanglement is 500 m/min or less. 8 The tension before and after the air entanglement nozzle during fluid entanglement is
The method for producing a polyester multifilament yarn according to claim 5, 6, or 7, characterized in that the polyester multifilament yarn is 0.2 g/d or less.