JPS5848649B2 - False twisting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for reducing fluff by drawing and false-twisting thermoplastic synthetic filaments, particularly by performing drawing and false-twisting simultaneously in the same zone.

In recent years, there has been remarkable progress in innovative technology for the production of bulky processed polyester systems, and demands for high-efficiency, high-quality processed yarns have also become more severe for knitting machines, looms, and other preparation machines.

There are a wide variety of innovative methods for processing yarn, but the so-called in-draw method, which has recently become popular, is being implemented by modifying old false twisting machines.

The present invention is intended to solve one of the new problems that arise due to the fact that stretching and false twisting, such as in the case of twisting, are performed simultaneously in the same zone.

i.e. multifilament (filament yarn)
When the yarn is twisted, the yarn is suddenly deformed due to twisting and stretching, as in the case of in-draw, and weak yarns are generated in some areas, resulting in fluff.

Generally speaking, defects caused by fuzz require stricter reduction in fuzz as the process progresses from knitting to weaving, and the fuzz specification has become particularly important in recent innovative looms.

As a result of intensive research into solving this problem, the inventors of the present invention used a highly oriented polyester filament yarn (yarn) with a birefringence index △n of 150 x 103 to 80 x 103, and combined it with a yarn supply roller. In order to increase the distance between the heat-fixing heaters for the twisted yarn, the normal yarn path is pushed forward at a right angle using a satin-metsuki bar guide, and the yarn is approximately 36 mm thick using the bar guide.
It has been found that the generation of fluff can be reduced by bending the sheet at 0° and guiding it to a heat fixing heater.

゛It is desirable that the length of the yarn path be extended by this matte bar guide as long as possible, but the distance (II) for protruding the yarn forward as shown in Fig. 2 should be approximately 20C1'ft or more and approximately 45CTL for ease of threading and installation. This is appropriate from this point of view, and moreover, this guide should be in a non-rotating state as shown in the following Examples and Comparative Examples.

As explained in JP-A-48-35112, the use of highly oriented yarns when drawing and false twisting polyester yarns reduces the occurrence of fuzz and reduces the occurrence of untwisted yarns as the yarn becomes more oriented. The range is also narrower, and the stable setting range for false twisting conditions can be widened.

In particular, as the highly oriented supply yarn used in the present invention, △n=
The effect is particularly noticeable when using a yarn of 50 x 103t, a yarn with poor cohesiveness and a lot of looseness, or a spinning yarn whose spinning oil is not suitable for false twisting as a feed yarn, and prevents the occurrence of fuzz. significantly reduced.

Normally, the occurrence of fuzz is closely related to the false twist tension, and in particular, the fuzz increases or decreases as the tension T2 increases or decreases after passing through the false twister.

In order to reduce fuzz, there is generally a method of reducing T29. In terms of in-draw, this is done by lowering the draw ratio, but when the draw ratio is lowered, there is a tendency for untwisting to increase, and sometimes Lowering T2 is not necessarily a good strategy for fuzzing, as it may result in yarns with low toughness due to insufficient stretching.

This phenomenon is particularly likely to occur in false twisting machines with a short yarn path distance between the supply roller and the heat fixing heater, and in such machines the twisting of the yarn during running goes back up the heat fixation heater and passes through the supply roller. It is spreading at nip point 1.

This spread of twist occurs regardless of the distance between the supply roller and the heat fixing heater.

This ripple effect of twisting is caused by deformation due to twisting of the yarn which has not yet been drawn and has not been heated enough to withstand deformation. A larger stress due to twisting acts more intensively on the filament than on the inner filament, resulting in damage to the filament.
In some cases, it has the negative effect of causing fluff.

The present invention aims to alleviate this tendency. In other words, the sudden change caused by the influence of twisting on immature yarns is alleviated and this is done in stages, thereby smoothing the migration of filaments in the twisted yarn. Become.

That is, the transition of the filament from the outer circumference to the inner circumference or vice versa is prevented from occurring at an acute angle.

Conventionally, methods for preventing twist from spreading to the double point of the supply roller are found in Japanese Patent Application Laid-Open No. 50-107245 and others, but these methods produce quite sharp steps in the twist distribution, and the above-mentioned outer periphery and Migration of the filaments due to twisting on the inner periphery is not smooth, and a sufficient fuzz reduction effect cannot be achieved.

1. If false twisting is carried out in the original state of the false twisting machine without any special modification between the supply roller and the heat regulating heater, fuzz will occur and, in addition, low toughness yarns will occur frequently.

As an invention with a twist prevention effect, Japanese Patent Application Laid-Open No. 49-12
No. 357 is a method using rotating rollers, and FIG. 3 described therein is a method similar to the present invention, but the position of the roller 4d in FIG. 3 is movable and the proper position is also regulated. It differs from the present invention in that it rotates only once, and also prevents twisting by 100%, which is completely different from the purpose of the present invention.

In order to improve this, the present inventors increased the distance between the heater and the roller, and in addition, in order to prevent uneven distribution of twist on the non-rotating matte bar guide, the twisted yarn itself can move freely on the bar guide. The advantage is that it can be rolled and moved.

This allows the stress caused by twisting to be constantly applied to the entire yarn to be dispersed, thereby successfully eliminating cut fuzz caused by stress concentration.

According to the study results of the present inventors, JP-A-50-1072
45, in which a guide is inserted and the thread path is hardly changed, is old-fashioned and ineffective, but the effect can be seen by increasing the distance (l) between the satin bar guide and the original thread path by 200 ml+ or more.

If l exceeds 450 mm, the effect will not change, and the operability will be disadvantageous, so the appropriate distance is approximately 4501rL7n.

The effect of distance (7) is to smooth the migration of filaments during twisting, and in twisted yarns and filaments, one filament is located in the inner layer of the yarn in some areas and in the outer layer in other areas, which is repeated. This ensures uniform twisting and prevents concentrated stress from being applied even if each filament is twisted.

This effect is particularly noticeable in the false twisting machine shown in Figure 1, in which the yarn path is not limited and the yarn moves arbitrarily on the bar guide as the twist propagates, as in the satin bar guide. This allows the overall twist to be balanced.

In practice, the method of continuously distributing the twist existing between the heat setting heater and the supply roller is to install a satin bar guide at least 200 mm away from the normal yarn path, and bend the yarn after it exits the supply roller. Just hang it on this bar guide and return it to the heat fixing heater.

In this case, so that the twist distribution is as continuous as possible,
The heater guide, which is installed so as to bend into the matte bar guide, should be made of a material with a low coefficient of friction and heat resistance.

The satin bar guide, on which the yarn bends after coming out of the supply roller, should have an outer diameter of 5 to 50φ (preferably 10 to 25φ) and a satin finish roughness of 5 to 10 s (Ha = 1.5μ average value). be.

Rather than installing a guide in which the yarn path is fixed in this area, it is better to use a bar guide where the yarn path is not fixed, and the yarn constantly moves depending on the transmission state of the twist, in order to increase the life of the guide and make the twist distribution more uniform. convenient.

Here, the roughness is 1 as described in JP-A-49-124357.
If you are expecting a twist-stopping effect of 00φ, 0.8 seconds or less seems to be good, but here, in order to make the twist distribution as continuous as possible, it is better to use something with relatively little twist-stopping effect.

When the thread path is shifted from the conventional thread path, the angle θ does not need to be strictly defined, and it is best to set it at approximately 90°, and this can be determined appropriately from the viewpoint of thread threading workability, but it is better not to vary drastically from 900. is preferable.

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a schematic diagram for implementing the present invention.

In the figure, a supply yarn 1 is supplied by a supply nip roller 5 via guides 2 and 3 and a tension adjustment device 4, passes through a satin bar guide 6 that bends the yarn, a yarn guide 7, and enters a heat fixing heater 8. The yarn, which has been stretched in the preparation section and simultaneously given false twist by the false twister 9, is fixed by a heat fixing heater.

At the same time as passing through the twisting device, the yarn is untwisted, passed through a delivery roller 10, passed through a secondary heat correction device if necessary, and wound into a package 11 via a winding device.

As shown in Figure 2, the satin bar guide is placed 200 meters from above the supply roller and heat fixing heater wire so that the bent yarn path is almost at right angles.
Heat-fixing heaters installed at positions separated by mm or more are installed so as to give distribution to the twists coming back.

The present invention will be explained below with reference to Examples.

Example 1 A polyethylene terephthalate polymer with an intrinsic viscosity of 1i0.65 was melt-spun using a conventional method to obtain a birefringence of 23×10−3.
Yarns of 300d and 32f were obtained.

Using the apparatus shown in FIG. 1, the original yarn was stretched 1.98 times and subjected to indraw false twisting at a heat treatment temperature of 190° C. and a twist of 2490 T/M.

At this time, the distance from the supply roller to the satin bar guide (
Twist distribution and end face fluff of false-twisted cheese when changing l)
ke/kg)-%' and the number of untwisted parts are shown in the following table.

Note that To is the number of twists that the yarn has on the supply yarn side from the satin bar guide, and T1 is the number of twists that the yarn has on the heater side from the bar guide.

Example 2 A polyethylene terephthalate polymer having an intrinsic viscosity of 0.65 was melt-spun using a conventional method to obtain a birefringence of 25×10”.
-" yarns of 300d and 48f were obtained.

Using the apparatus shown in Fig. 1, this yarn was stretched 1.90 times at 190°C. False twisting was performed with a twist of 2550T/M.

The * mark indicates a comparative example, and the results are obtained when 6 and 7 in Fig. 1 are mirror-finished rotatable rollers.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of the present invention implemented in a false twisting machine, and FIG. 2 is a schematic diagram of the main parts of the present invention.

Claims (1)

[Claims] 1. When simultaneously drawing and simultaneously false-twisting a polyester filament yarn having a birefringence index of 15 x 103 to 80 x 103, the running yarn is bent between a heat fixing heater and a supply nip roller upstream of the heater. The bar guide of Nashiji Metsuki, which changes the path, is 200 to 45 minutes from the original path.
A false twisting method characterized by providing a bar guide 0 mm forward in a non-rotating state, hooking the yarn on the bar guide and folding it back.