JPS5934810B2 - False twisting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semi-drawn yarn (hereinafter referred to as TF-drawn yarn) of a polyester fiber yarn having a large degree of elongation at break obtained by complete drawing after high speed spinning or normal speed spinning.

) regarding a new false twisting method. Until now, in order to obtain false-twisted yarn from semi-drawn yarn, including undrawn yarn spun at normal speed, a method called the drawn false-twisting method has been used in which drawing and false-twisting are performed in one step. .

This method can be roughly divided into two types: a continuous stretch false-twisting method in which stretching is followed by false-twisting, and a simultaneous stretch false-twisting method in which stretching and false-twisting are performed in the same area.

Among these, the former is a method in which the false twisting machine has a stretching zone consisting of a stretching roller, a stretching bin, a stretching plate, etc., and the stretching and false twisting processes are performed continuously, whereas the latter is a method in which the false twisting machine Since this is a method of simultaneously stretching the material in the heating range of 1, it is possible to use a normal false-twisting machine as is without much modification, and this false-twisting method has recently become mainstream.

Furthermore, with the improvement of winding technology in recent years, highly oriented undrawn yarn with excellent heat resistance and storage stability has become generally available due to the dramatic increase in spinning speed.
It can be threaded without melting even when it comes into contact with a high-temperature false-twisting heater, and it has better heat-set properties and better crimp characteristics than when conventional drawn yarn is false-twisted or when it is continuously drawn and false-twisted. Since the processed yarn with the same crimp characteristics can be obtained from the undrawn yarn, it is necessary to lower the processing temperature to reduce energy loss, shorten the length of the heater, or increase the processing speed. The advantages of the above-mentioned undrawn yarns, such as yield, are becoming widely recognized.

The reason for this is that many points are unclear, but it is thought that the highly heat-sensitive yarn, which has not undergone any heat treatment before false twisting, is heated, stretched, and heat-set all at once.

However, even in this case, the stretching has actually been completed in the heat-setting zone, so the heat-setting effect is still insufficient, although it is improved compared to the drawn yarn.

Therefore, as a result of intensive studies on means to further improve heat-setting properties, the present inventors have determined that semi-drawn yarn with high elongation that has not been subjected to heat treatment should be simultaneously stretched and false-twisted at a draw ratio as low as possible. On the other hand, when a semi-drawn yarn with a high elongation is simultaneously stretched and false-twisted in a low-drawn state, the resulting yarn becomes a highly twisted filament due to its easy meltability and low tension. There is a problem that a normal crimped yarn with stretchability and bulkiness cannot be obtained because the yarn becomes a crimped yarn, and the present inventors have achieved the present invention by solving this problem.

That is, the present invention uses a semi-drawn polyester fiber yarn having a breaking elongation of at least 40% at a primary draw ratio of 1.05.
False twisting is performed using a fluid heating element so that the heating tension is 0.02 to 0.07 g/d and the heating tension is greater than the untwisting tension, and then 1.05 to 1.7 g/d is used.
This method is characterized by stretching at a secondary stretching ratio of 100%.

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

In FIG. 1, the semi-drawn yarn 2 pulled out from the pan cage 1 passes through a guide 3, a supply roller 4 and a take-up roller 7.
It undergoes primary stretching between the two, and is strongly twisted by the fluid heating element 6 provided therebetween, and in this state is heat set by the heater 5.

Next, the secondary draw ratio is adjusted appropriately between the take-up roller 7 and the stretching roller 8 depending on the application, and a false twisted yarn is obtained. It is wound up into a package 10 that rotates in contact with the package 10 .

Further, if necessary, secondary heat setting is performed using the secondary heater 11 to obtain a substantially non-torque yarn.

The reason why a semi-drawn polyester fiber yarn with a breaking elongation of 40% or more is used in the present invention is because a sufficient thermoceramic I-PIE cannot be obtained with a semi-drawn yarn with a high degree of orientation of less than 40%. Semi-drawn yarn of 60% or more is preferable.

However, if the elongation at break is more than 250%, the thermal stability is extremely poor, and problems may arise in the storage stability and handling of the semi-drawn yarn, so it is better to use one with an elongation at break of less than 250%.

Table 1 shows the results of false twisting semi-drawn polyethylene telescrate yarns having various elongations at break using the apparatus shown in FIG.

The conditions here are that the yarn speed at the supply roller is 10.0.
m 7m1yt, primary draw ratio is 1.00, secondary draw ratio is 1.10, heater temperature is 200'C, supply pressure of fluid heating element (air is used in the one in Figure 3) is 4,5
kg/iG.

As is clear from Table 1, the operability varies greatly depending on the elongation at break, and elongation at break of 40 to 200% is more preferable.

Yarn that satisfies these conditions may be obtained by drawing undrawn yarn obtained by ordinary low-speed spinning at an appropriate draw ratio without heating, but from the viewpoint of operability, it is overwhelmingly possible to obtain yarn by high-speed spinning and winding. The obtained product is superior and economically advantageous.

For example, for polyester, the spinning winding speed is 2000~
OOOm/min.

It is preferable to use something of about 100%.

Next, the primary stretching ratio is 1.05 or less, and the heating tension is 0.02.
~o, o7g/a (D is the denier of the supply system) is to prevent the semi-drawn yarn from being drawn to a large extent.

That is, first, since the yarn is drawn at the primary draw ratio, the effect of the present invention will not be exhibited unless the draw ratio is 1.05 or less.

Therefore, in general, the stretching ratio in the simultaneous stretching false twisting method is
The actual situation is that the draw ratio is slightly lower than the normal draw ratio applied in a drawing machine or continuous draw false twisting method, but in the present invention, the yarn axis of the supplied semi-drawn yarn is set to 1.
．． Heating and heat setting are performed under a low tension that does not cause the elongation to exceed 0.5 times.

In addition, the reason why the heating tension is set to 0.02 to 0.07.9/d (D is the denier of the supply system) is due to operability and heat set t't.
This is because we took into account.

Figure 2 shows this relationship.

Figure 2 shows 245D semi-drawn polyethylene telescrate yarn obtained by high-speed spinning winding of 3100 m x 7 ml yi.
The relationship between the heating tension and the denier of the obtained processed yarn is shown.

When the heating tension exceeds 0.07.9/d, the yarn is stretched to almost the same stretching ratio as applied in the simultaneous stretching and false twisting method (the processed yarn denier is about 155D), so the heat setting property is poor. descend.

On the other hand, if the heating tension is less than 0.02 g/d, operability will deteriorate due to ballooning due to heating.

This is generally true of the materials used in the present invention.

Next, the reason why the heating tension is made larger than the untwisting tension is to keep the tension in the heating area within a certain appropriate range and control ballooning etc. when processing at a stretching ratio that does not substantially cause stretching. This is to maintain good operability.

In other words, in general, the operability of a false-twisting machine can be improved by increasing the heating tension to prevent ballooning and tension fluctuations, but if you try to maintain this heating tension at the stretching ratio, it will take a long time. Stretching occurs.

Therefore, in the present invention, the heating tension is increased and the untwisting tension is lowered, by reversing the tension relationship from that of a normal pink Eve heating element, thereby increasing the heating tension even though the stretching ratio is low. be.

For this purpose, a pin-wave heating element having a pin that actively rotates in the running direction of the yarn is used, or a friction twister with a thread-feeding component, such as a friction twister with multi-stage discs arranged on three axes, is used. Although it is not impossible to do so, the former cannot increase the yarn speed due to mechanical constraints on the pin rotation speed, and the latter has low yarn tension, resulting in poor heating efficiency.

In the present invention, fluid heating element 7 is preferred. An example of the fluid heating element is shown in FIGS. 3 and 4.

A compressed fluid is injected from a fluid source (not shown) substantially tangentially into the thread passage 16 through the fluid introduction hole 15 so as to have swirling properties, and heats the running thread 2.

Here, the yarn passage 16 is provided with a constriction portion 17 that acts as a heating point and an untwisting point for the yarn 2.

This constriction part 17 determines the discharge direction of the fluid from the yarn passage 16, and in order to realize the method of the present invention in which the heating tension is made higher than the untwisting tension, it is necessary to The throttle part 17 must be provided on the upstream side of the fluid introduction hole 15, that is, in the same direction as the traveling direction of the yarn 2, so that more fluid can be discharged.

Next, in the present invention, the yarn obtained in the false twisting region is plucked 1.
05 to 1.7 times.

Here, "continuing" means successively or separately.

In other words, the yarn that is strongly twisted and heat-set in the false twisting region takes the form of a highly twisted yarn, and depending on the heater temperature, it becomes rough and stiff in the fused state, and if left as it is, it will not be suitable for special fields. It cannot be used as a general yarn except for the

In contrast, the present invention reduces the thickness of the yarn by stretching it by 1.05 to 1.7 times after the false twisting region or in a separate step, thereby reducing the apparent fused state. The yarn is separated in filament units to improve the strength and elongation of the processed yarn, but by appropriately adjusting the stretching ratio, the state of filament separation can be freely controlled and the most complete separation can be achieved. In some cases, it can be made to have almost the same quality as ordinary false twisted yarn.

Here, if the secondary stretching ratio exceeds the primary stretching ratio applied to the usual simultaneous stretching false twisting method, the tension increases and the crimp imparted in the false twisting region disappears. The subsequent stretching ratio must be less than or equal to the stretching ratio applied to the simultaneous stretching and false twisting process.

In order to confirm this, a semi-drawn yarn (245D) with a breaking elongation of 88% (polyethylene terephthalate obtained by high-speed spinning at a winding speed of 3100 m/ynm) was used at a yarn speed of 100 m/mvt at a feeding roller and a primary draw ratio. 1.OO, the heater temperature was 200QC, the supply air pressure of the fluid heating element was 4.5 kg/crit G, and the secondary stretching ratio was variously changed.

Crimp characteristics (Figure 5) and residual torque (Figure 6) at this time
According to the above, it can be seen that by increasing the secondary draw ratio, the fused filaments are opened, the crimp characteristics are increased, and the residual torque is decreased.

From these results, in the present invention, the secondary stretching ratio is 1.05.
~1.7.

Preferably, the product of the primary stretching ratio and the secondary stretching ratio applied in the present invention is 0.1 of the stretching ratio of the simultaneous stretching and false twisting method.
~1.0 times is better.

Here, the crimp property is determined by making 8 rolls with a tension of 2/1000g/d, hooking it up and immersing it in hot water at IOO'C for 5 minutes without any weight, and then soaking this sample in hot water. Take it out and apply a load of 0.2 g/d while it is still wet.
Measure the length a after 1 minute, then remove the load and dry it in a dryer at 60°C for 30 minutes while hanging it on a hook without any excess weight, and leave it in a test room under standard conditions for more than 1 hour.0.002
The length b was measured 1 minute after applying a load of g/d, and calculated using the following formula.

In addition, the torque was determined by making one loop with a frame circumference of 30 crIL, applying a load of 0.005.9/d, leaving it to stand still, and then using a twister to apply a load of 0.1 g/d to the loop. Tighten it straight, set the distance between the grips to 10CrrL (leaving 2.51 at both ends), and calculate the number of twists T and the length of the twist L.
− was calculated using the following formula.

As described above, according to the present invention, since the false twisted yarn having stretchability and bulky properties is processed from a semi-drawn yarn with high elongation in a state with good heat setting properties, it can be processed into a false twisted yarn with good heat setting properties. This can be easily obtained by using a heater that is slightly lower, faster, and shorter than the applied temperature and heating time.

Furthermore, without any modification to the conventional false twisting machine, and with good operability, a wide variety of processed yarns, from ordinary crimped yarns to fused yarns, can be easily obtained.

[Brief explanation of drawings]

The drawings relate to the present invention; FIG. 1 is a schematic side view of the apparatus used in the present invention, FIG. 2 is a graph showing the relationship between heating tension and processed yarn denier, and FIG. 3 is a diagram showing the relationship between heating tension and processed yarn denier. FIG. 4 is a longitudinal cross-sectional view of a fluid heating element used in FIG.
It is a graph showing the relationship between the next draw ratio and the crimp customization or torque. 4... Supply roller, 6... Fluid heating element, 7... Take-up roller, 8... Stretching roller, 14... Squeezing section .

Claims (1)

[Claims] 1 A semi-drawn polyester fiber yarn having a breaking elongation of at least 40% is heated at a primary draw ratio of 1.05 times or less, a heating tension of 0.02 to 0.07 g/d, and the heating tension is an untwisting tension. 1. A false-twisting method characterized by performing false-twisting using a fluid heating element so that the material becomes larger than the original size, and then stretching at a secondary stretching ratio of 1.05 to 1.7 times.