JPS5947732B2 - Manufacturing method of fused alternately twisted yarn - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Technical Field of the Invention The present invention relates to a method for false twisting a thermoplastic fiber multifilament yarn to produce an alternately twisted yarn having fusion bonding.

More specifically, the present invention relates to a method for producing a fused alternately twisted yarn that can effectively form a fabric exhibiting a strongly twisted yarn-like texture and a light pattern.

Conventional techniques and their problems Conventionally, many techniques are known in which untwisted yarn portions and overtwisted yarn portions are alternately formed by false twisting.

For example, an example where polyester-based drawn fibers or polyamide-based drawn fibers are false-twisted using a spindle-type false-twisting device at extremely high heating temperatures that cause the fibers to fuse together. However, the Special Public Interest Publication No. 50-25065
No. Publication, Special Publication No. 51-225, Special Publication No. 51-42
It is described in Publication No. 662, etc.

Examples of false twisting of drawn fibers under high retraction supply using a false twisting device that applies fluid swirl flow are disclosed in JP-A-51-143746 and JP-A-51-1999. 14
It is described in Japanese Patent Publication No. 3749, Japanese Patent Publication No. 53-15188, Japanese Patent Publication No. 30818-1983, etc.

Additionally, Japanese Patent Application Laid-Open No. 53-98444 and Japanese Patent Application Laid-open No. 52-66748 are known as related technologies, but since these technologies use driftwood false twisting, ballooning occurs and the obtained The unfused and untwisted portions were short and fragmented.

Therefore, the strong twist style was not a satisfactory method for creating Kasuri patterns.

In addition, there is a technique that applies an active unsteady action to the yarn that is being subjected to the false twisting process.

For example, as a technique for varying the contact state between the yarn and the heating device, Japanese Patent Laid-Open Nos. 49-66928 and 51-Sho.
15017, Japanese Patent Application Laid-open No. 52-8119, etc., and Japanese Patent Publication No. 51-34016 and Japanese Patent Application Laid-open No. 49-554 as a technique for varying the twist propagating from the false twisting device toward the heating device. , JP-A-50-121546, etc.; Japanese Patent Publication No. 49-8414, JP-A-49-108353, Japanese Unexamined Patent Publication 1983-1961
745, etc., and Japanese Patent Application Laid-Open No. 49-92337 as a technique for varying the speed of yarn passing through a false twisting device.
JP-A-49-92354, etc., as a technique to make the yarn to be false-twisted non-uniform in the length direction.
JP-A-52-66722, JP-A-53-8174
No. 9, Japanese Patent Application Laid-Open No. 101654/1984, etc.

All of the above conventional techniques form alternately twisted yarns by false twisting, but in addition to clear S-twisted yarn portions and Z-twisted yarn portions, they also form a large amount of untwisted yarn portions similar to normal false-twisted yarns. , a relatively long untwisted yarn section is formed between the S-twisted yarn section and the 2-twisted yarn section, or the twist density in the untwisted yarn section or the threaded yarn section is high in the center and low at both ends. If the twist density of the untwisted yarn portion or each twisted yarn portion is not constant, or if the length fraction of the untwisted yarn portion of the entire yarn cannot be formed high, the average twist density of the entire yarn may be increased. It has a defect that cannot be used.

Alternatively, the yarn may have a twist in the false-twisting heating direction, but it has been untwisted to the extent that the false-twist crimp is exposed, and it is formed as an untwisted yarn portion that has lost its tightness. Although the fibers have a twist in the twist direction, the fibers are strongly fused together and are untwisted without exposing the false twist crimp, resulting in untwisted yarns that have lost their bulk. It has a defect in that it is not possible to clearly form a difference in form between the untwisted yarn portion and the untwisted yarn portion.

C. Object of the present invention The present invention provides a method for producing fused alternately twisted yarn, which can improve the drawbacks of the above-mentioned prior art and can effectively form a fabric exhibiting a strongly twisted yarn-like texture and a light Kasuri pattern.

That is, the present invention provides a technique in which almost no untwisted portion is formed, and the length of the fused portion can be increased, even though the degree of fusion is light.

2. Structure of the present invention In order to achieve the above object, the present invention consists of the following structure.

``When false twisting multifilament yarn made of thermoplastic synthetic fibers, a circumscribed friction false twister is used as the false twisting device, and the number of false twists is made smaller than the number of twists that occur in double twisting.
The amount of yarn supplied to the false twisting area is retracted more than in normal false twisting, and the false twisting temperature is used as the fusion temperature of the yarn, so that the fusion is such that some of the constituent filaments peel off during the untwisting process. A method for producing a fused alternately twisted yarn, characterized in that the fusion to the extent that it peels off is maintained even immediately after passing through a false twisting device, and further the false twisting process is performed by lowering the passing resistance of the yarn in the untwisting region. .

In the present invention, it is necessary to use a circumscribed friction false twister.

This is to give a feeding effect to the yarn, reduce passing resistance, lower processing tension, prevent ballooning, and perform false twisting in a substantially stationary state.

Next, the number of false twists needs to be smaller than the number of twists that generate double twists.

This is to prevent false twist ballooning.

If the number of twists is high enough to cause double twists, the number of twists will fluctuate and the yarn will vibrate, which is not preferable.

Next, it is necessary to supply the yarn to the false-twisting region in a smaller amount than in the normal false-twisting.

This is to reduce the yarn tension in the untwisting region of the false twisting process and to compensate for twisting shrinkage.

Therefore, it is possible to prevent the untwisted and fused portion from being shredded and destroyed.

The specific value of the retraction supply amount is several percent to several percent higher than that of normal false twisting.

Next, the false twisting temperature needs to be the fusion temperature of the yarn and a temperature at which the constituent filaments of the yarn separate.

More specifically, it refers to a temperature that is lower than the melting point of the thread, at which the constituent filaments are fused to each other while maintaining their fiber shapes.

When such a false twisting temperature is adopted, when a large deformation of untwisting is applied to a multifilament yarn whose fibers are fused to each other in the twisted state, the twisted yarn structure cannot undergo large deformation strain, and the fibers The poorly structured areas, ie the fused areas, will peel off.

Next, in the present invention, it is necessary to maintain the above-mentioned fused state even immediately after passing through the false twisting device.

This is to form a relatively long fused portion and give it a strongly twisted appearance and texture.

Most of the fused yarns used in the conventional method have their fused portions cut into short pieces when they pass through a false twisting device.

Next, in the present invention, it is necessary to reduce the resistance to thread passage in the untwisting region.

Here, the untwisting area refers to the area downstream from the false twisting device up to the delivery roller.

If the passing resistance of the yarn is high in such an untwisted region, the yarn tension will be high and the fused twist will be broken into pieces, which is not preferable.

E. Effects and Functions of the Present Invention In the past, many attempts have been made to improve the deficiencies of the prior art described above, but they are still incomplete.

This is because previous research has focused on optimizing external factors for forming alternately twisted yarns, such as false twisting conditions such as number of false twists, processing tension, and heating temperature, physical properties of processed raw yarn, and structure of false twisting equipment. This is because the formation mechanism of alternately twisted yarns was unclear.

The formation mechanism of alternately twisted yarns has an important meaning in the present invention.

Of course, the above-mentioned external factors are also important, but they alone do not lead to ideas for improving the deficiencies of the prior art as described above.

Although the formation of alternately twisted yarns by the false twisting process is caused by the false twisting device and its upstream, the formation of the alternating twisted yarn itself is performed downstream of the false twisting device.

In the prior art, when observing the yarn immediately downstream of the false twisting device, there are various states such as when an untwisted yarn portion is formed, when a threaded yarn portion is formed, and when a non-twisted yarn portion is formed. happens.

The formation of the untwisted yarn portion is also diverse, and roughly divided into cases where the untwisted yarn portion that is being formed rotates in the false twist direction commensurate with its twist density, and cases where the untwisted yarn portion that is forming rotates less than that. In the latter case, the number of twists upstream of the false twisting device is reduced.

The formation of the twisted yarn portion is accompanied by an increase in the number of twists upstream of the false twisting device.

The untwisted yarn portion may be formed as a transient phenomenon between the untwisted yarn portion and the twisted yarn portion, or may be formed clearly continuously.

When observing the area slightly downstream from the immediate downstream of the false twisting device, no new untwisted yarn portion is formed in this area.

The untwisted yarn portion is formed when an untwisted yarn portion is formed immediately downstream of the false twisting device with rotation of the yarn, and when the downstream end portion of the untwisted yarn portion is untwisted and formed sequentially. If an untwisted yarn portion exists downstream of the untwisted yarn portion, the untwisted yarn portion may be heated and formed.

The untwisted yarn portion may be formed by the twists of the untwisted yarn portion and the twisted yarn portion offsetting each other.

In the prior art, as described above, there are various formations of alternately twisted yarns, resulting in the above-mentioned defects.

In the present invention, it has been found that it is most efficient to form an untwisted yarn portion with rotation of the yarn immediately downstream of the false twisting device, which is sometimes observed in the above-mentioned prior art, and this formation is continued almost all the time. This was particularly successful, and furthermore, the untwisted yarn portion, which involves rotation, is brought into a state almost equivalent to the so-called false-twisting heating state upstream of the false-twisting device.

Looking at it from another perspective, the state in which the false-twisting heating region extends to the downstream of the false-twisting device is maintained at all times.

In this way, while the tip of the false-twisting heating area located downstream of the false-twisting device rotates, the rotating portion untwists the rear end portion of the previously formed untwisted yarn portion and the tip portion of itself. The tip of the false-twist heating region moves downstream while forming over-untwisted portions one after another.

The rotation of the tip of the false twisting heating area will eventually stop when it is gripped by a take-up roller, comes into contact with a guide or the like, or the rotational force applied by the false twisting device can no longer be transmitted.

Even if the rotation of the tip of the false-twisting heating area stops, the false-twisting device continues to apply rotational force, so in the next moment a new untwisting point is created between the tip of the false-twisting heating area and the false-twisting device. occurs, and that point becomes the tip of a new false twist heating region, and the above phenomenon is repeated, resulting in an alternately twisted yarn in which untwisted yarn portions and twisted yarn portions are alternately formed.

The sister of the present invention can be achieved by paying attention to and observing the above-mentioned phenomena and selecting the false twisting mode and false twisting conditions.

The findings obtained in the present invention are listed below.

(1) The operation of the false twisting system whose main devices include a supply device, a heating device, a false twisting device, a take-off device, etc. is not substantially changed.

(2) Since the obtained yarn is in a highly twisted state, the percentage of
It has a twist of .

Therefore, retraction supply conditions commensurate with the twisting are adopted.

(3) When the untwisted yarn portion is untwisted, the twist density of the entire untwisted yarn portion does not gradually decrease, but only a portion is untwisted, and the twist density of the untwisted yarn portion does not change and the twist density gradually decreases. It is best to untwist the yarn in such a way that it becomes shorter and the untwisted yarn portion absorbs much of the twist and becomes an untwisted yarn portion that gradually becomes longer.

For this purpose, it is preferable that the untwisted yarn portion has high cohesiveness and high torsional rigidity, does not lose convergence once untwisted, and has low torsional rigidity.

For this purpose, it is necessary to provide an appropriate degree of fusion, that is, a degree of fusion that causes part of the fusion in the untwisted state to be peeled off during the untwisting process.

The heating temperature should be selected in consideration of the physical properties of the yarn material and the physical properties and amount of surface deposits such as oil.

The extent of the fusion is so light that it can be completely removed by forcibly untwisting the obtained yarn using a twister or the like.

(4) As for the twist density of the untwisted yarn portion, the twist density of the false twist heating remains almost unchanged, so it is preferable that the number of false twists is high, but if the number of false twists is too high, double twisting will occur and false twisting will occur. The number of twists passing through the twisting device fluctuates, or the heating force of the false twisting device approaches or exceeds the gripping force limit, causing intermittent heating.
This causes the formation of untwisted yarn portions.

As a guideline, it is preferable to use a slightly lower number of false twists than the normal false twist process.

(5) Vibration of the yarn during processing, especially ballooning in the vicinity of the false twisting device, is undesirable as it may cause the untwisted yarn to become fragmented or cause a loss of stability in processing, so quiet untwisting is recommended. I need.

For this purpose, it is preferable to prevent ballooning from occurring as much as possible, and to such an extent that ballooning cannot be recognized with the naked eye.

(6) If the yarn tension downstream of the false twisting device is high, the twists of the untwisted yarn portion and the twisted yarn portion may cancel each other out, or the twisted yarn portion may not have a high twist density, or the false twisting device It is undesirable that the fibers are untwisted at the same time as they pass through.

Therefore, it is preferable to weaken the yarn tension as much as possible, and the passage resistance of the false twisting device and guides must be reduced.

(Force) If a strong abrasion action or large deformation of curvature is applied to the false twisting device or upstream thereof, the above (6)
In addition to problems similar to the above, the fusion bond may peel off or the twisted structure may be destroyed in the twisted state, resulting in a decrease in cohesiveness, and the material is often untwisted as soon as it passes through the false twisting device. , undesirable.

It is necessary to perform false twisting to avoid strong abrasion or large curvature deformation.

Although the present invention is not limited to the above seven items, in false twisting thermoplastic fiber multifilament yarn,
If carried out in accordance with at least the above seven items, the immediately downstream portion of the false twisting device can be kept in a constant false twisting heating mode, and alternately twisted yarns are formed according to the yarn forming mechanism as described above, and the present invention You can obtain yarn that suits your purpose.

Effects of the Present Invention According to the method of the present invention, almost no untwisted yarn portion is formed, the untwisted yarn portion has almost the same twist density as in the false-twist heated state, and the untwisted yarn portion has a strong twisted structure. Since it is formed by successively heating until the torque is balanced with the untwisted yarn portion, the twist density is high and uniform.

A yarn with excellent characteristics such as the following can be obtained.

Furthermore, since the untwisted yarn portion can be a long portion, it has a strongly twisted texture and appearance, and since it is a false twisted yarn, it has the same characteristics as a real highly twisted yarn.

Furthermore, since the untwisted yarn portions remain even when the fabric is made, it exhibits a light splashed pattern and a unique design effect as a differentiated yarn.

This will be explained below using examples.

Example 1 Polyethylene terephthalate was melt-spun to produce 3000
m/mi! A multifilament yarn with a thickness of 137 denier and 36 filaments was made.

While this yarn was stretched 1.4 times, false twisting was performed in the stretching region at a heating temperature of 235° C. and a false twist number of 3200 T/m.

A circumferential friction false twisting device was used as the false twisting device.

During this processing, a part of the false twisting device and the state of about 5 mm of yarn downstream of the false twisting device can be observed.
I took some photos.

From these photographs, it was confirmed that the yarn was completely untwisted immediately downstream of the false twisting device.

It should be noted that 4 of the 300 sheets were found to contain some over-untwisted portions within the approximately 5 mm.

The obtained yarn has untwisted yarn portions and overfolded yarn portions alternately formed, and the twist density is 3100 T/m and 18 T/m, respectively.
00T/m, and the average length is 37mvt16 each.
It was 3 mvr.

Almost no untwisted yarn portion was formed.

When a fabric was formed using this yarn, it was possible to obtain a fabric that exhibited a strongly twisted yarn-like texture and a light Kasuri pattern that could never be achieved with conventional alternately twisted yarns.

In the above experiments, the stretching was 1.4 times in the false twisting process, but the stretching was 1.65 to 1.1 times in the normal false twisting process.
Stretching 70 times is suitable.

Therefore, it provides more retraction than normal false twisting.

By doing so, it is possible to provide the twisting shrinkage and to lower the tension during heating and untwisting.

Further, a circumferential friction false twisting device was used as the false twisting device, and the yarn speed at the portion in contact with the yarn, that is, the circumferential speed of the disk of the 3-shaft type friction false twisting device was set to 2.13 times the yarn speed.

As a result (including the conditions described later), the tension during heating and untwisting was both 13 g.

As a result of increasing the speed of the false twisting section to 2.13 times the yarn speed, the passage resistance of the false twisting device was made O.

In addition, the external friction false twisting device was able to apply only rotation to the yarn without causing it to revolve in the false twisting section, so it was possible to perform false twisting without causing ballooning.

Furthermore, in the external frictional false twisting device, since the bending of the yarn at the false twisting section is small, peeling of the fused portion does not occur here.

On the other hand, in the conventional spindle system, the diameter is 1~
Since the thread is wrapped around the two dragon pins, the thread bends a lot,
Furthermore, since the rotation axis of the spinner and the yarn axis do not match, the yarn revolves and ballooning occurs.

As a result, it is not possible to obtain a long untwisted part.

In addition, in the above actual case, the false twisting heating temperature of 235°C is the temperature that fuses the fibers of the yarn in the false twisting heating section, and the fusion is such that when the heating section is untwisted, the fusion bond separates. It was something.

Comparative Example 1 An experiment was conducted by changing the false-twisting device in Actual Case 1 to a false-twisting device using an air jet flow and a spindle false-twisting device, and keeping the other conditions the same.

As a result, there were many untwisted parts, untwisted yarn parts with a small amount of twist, and ununtwisted yarn parts where some of the fused yarns were peeled off.

When the yarn was observed immediately after passing through the false twisting device, it was found that various types of yarn structures were irregularly formed in this portion, such as a non-twisted state 5, a retwisted state, and an untwisted state.

In addition, strong ballooning occurred upstream and downstream of the false twisting device.

In particular, in the case of a spindle false twisting device, the yarn tension was high in the untwisted region, and there were particularly many non-twisted regions.

The obtained yarn did not have a strong twist pattern or appearance, nor did it have a light pattern.

Claims (1)

[Claims] 1. When false-twisting multifilament yarn made of thermoplastic synthetic fibers, a circumscribed friction false-twisting machine is used as the false-twisting device, and the number of false twists is made smaller than the number of twists that occur in double twisting, and the false-twisting area is The amount of yarn supplied to the yarn is retracted from that of the normal false twisting process, and the false twisting temperature is the fusion temperature of the yarn, and in the untwisting process, a part of the constituent filaments is fused to the extent that they are peeled off, Alternating fusion bonding characterized in that the fusion bond to the extent that the peeling is maintained even immediately after passing through the false twisting device, furthermore, the passing resistance of the yarn is low in the untwisting region, and the false twisting process is performed while preventing false twist ballooning. Method of manufacturing twisted yarn.