JPS584088B2 - Kasada Kagenshi no Seizouhouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a bulky yarn to obtain a spun yarn or a spun yarn-like multifilament yarn.

Conventionally, in order to directly obtain spun yarn from continuous finished fibers, a method has been used in which tows of several hundred thousand deniers are sequentially cut between high-pull rollers.

Such a method requires a large-sized device and requires complicated mechanical operations due to the large number of rollers.

In addition, since the fibers themselves are too strong, they cannot be cut easily, so a method of actively cutting the fibers with a rotating blade is also used, but the machine is difficult to maintain and it is difficult to make small adjustments to the product application. It has the following drawbacks.

Therefore, if the polyester multifilament yarn used for clothing could be easily cut, the equipment would be smaller, and the drafting process during spinning could be shortened or omitted, which would greatly shorten the spinning process. Fine count yarn, which is technically difficult, can be easily obtained.

However, when conventional multi-filament yarns of polyester for clothing are cut, the strength of each single fiber is uniform, so the single fibers are not randomly cut, and the entire yarn is broken in groups.

Therefore, if there are random weak points in the length direction of each single fiber of a multi-filament yarn and between the fibers, it can be cut with a simple device without the need for a large force.

For this reason, there are various methods known to damage the surface of the single fibers or to actively cut the fibers with a cutter, etc. However, the cutting conditions may differ due to changes in the cutter over time, and when the fibers are cut to a fine denier such as 75 deniers, It is very difficult to cut or damage the thread fibers because the whole thread is not strong enough.

Furthermore, even if a multi-filament yarn for tow or clothing is used as a spun yarn or a spun yarn-like yarn, the yarn itself does not have bulkiness, so the bulkiness is inferior to that of a bulky processed yarn such as a false twisted yarn.

In view of the deficiencies of the conventional method, the present invention provides a method for obtaining a bulky yarn for tension cutting that is easy to perform tension cutting using a simple method and device and has bulkiness itself.The present invention has the following structure. be done.

When heating and stretching polyester-based undrawn multifilament yarn having a birefringence Δn of (15×10”3)<Δn<(80×10−3) that is continuously supplied, the above-mentioned A method for producing a bulky yarn, characterized in that the temperature of the heating element is set to be higher than the crystallization temperature of the fiber, the stretching ratio is lower than the natural stretching ratio, and stretching is carried out so as to substantially contain almost no contracted portion. .

The present invention will be explained in more detail.

In the method for producing bulky yarn for tension cutting of the present invention, the supplied yarn has a birefringence Δn obtained by ultra-high-speed melt spinning (
The pre-orientated yarn with 15X10-3) < Δn < (80X10-3) has good drawability, little change in yarn quality due to aging, and high color fastness at weak points after drawing. Ordinary undrawn yarns and semi-drawn yarns also exhibit extremely excellent properties, with the birefringence Δn being (15X10-
3) It is necessary to use polyester-based undrawn multi-filament yarn with <Δn<(80X10-3).

In the method of the present invention, heating drawing in a heating zone in which a heating body is arranged is a method of drawing the undrawn yarn while heating it in the heating zone, particularly a drawing method using heating drawing pins. A stretching method in which the undrawn yarn is wound around a heating roller multiple times is not suitable for obtaining random weak points because the stretching points change and become fixed and aligned, and therefore are not adopted at all in the method of the present invention. It is something.

Accordingly, in the present invention, the heating zone refers to a generally long region in which a heating body such as a contact type hot plate or a non-contact type hollow heater is arranged.

The humidity of the heating element is set to be higher than the crystallization temperature of the fibers, and unless these conditions are satisfied, it is impossible to preferably impart random weak points in the length direction of the fibers and between the fibers.

Below the natural drawing ratio means below the point A at the end of the flow region ■ shown in the load-stretching curve of the undrawn yarn shown in Figure 3, and the drawing process has not completely finished, so the undrawn yarn There are a mixture of parts, semi-stretched parts, stretched parts, etc.

Thereafter, the tension increases again and the film is cut at point B of the maximum stretching ratio in the region (3).

Ordinary drawn yarns can be drawn by selecting an appropriate draw ratio between the natural draw ratio and the maximum draw ratio.

As the stretching degree continues to increase, as shown in Figure 3, the shape of the load-extension curve changes, the yield tension (■) and the tension in the flow region (■) decrease, and the natural stretching ratio also decreases. Maximum draw ratio increases.

By raising the humidity above the crystallization temperature of polyester fibers, the randomly mixed unstretched parts are crystallized with low orientation, making them brittle, and the stretched parts are crystallized with high orientation. This is to make them stronger.

FIG. 1 shows one embodiment of the present invention.

The undrawn polyester multifilament yarn Y drawn from the supply package ■ is subjected to pretension by the pretensor 2 and stretched between the feed roller 3 and the delivery roller 5 at a magnification equal to or lower than the natural stretching ratio. 4, the cheese leaves the delivery roller 5 and is wound up by the take-up roller 6 to form the cheese 7, and the process ends.

The principle of obtaining the bulky yarn for tension cutting obtained by the present invention is not clear, but it is a polyester undrawn multi-filament yarn that is stretched at a very unstable stretching ratio below the natural stretching ratio, and with hot pins, etc. By stretching without fixing the starting point, stretching unevenness occurs in each fiber of the multifilament yarn, and furthermore, by heat treatment in a very short time with a hot plate at a temperature higher than the crystallization temperature of the fiber, stretching unevenness occurs even more. As shown in Figure 4, the netting part a
, unstretched parts b, are not concentrated in one place in the filament, but are generated randomly in the length direction of the fiber and in the direction between the fibers, and as shown in Fig. The less strong fibers are sequentially cut by tension cutting.

In addition, since the shrinkage rate due to heat differs in the undrawn, half-drawn, and fully drawn parts that occur randomly in the length direction and interfiber direction of each fiber, the entire yarn is subjected to relaxing heat treatment. As shown in FIG. 6, crimp occurs due to the difference in heat shrinkage between the various fibers in the fiber length direction, resulting in a bulky yarn.

The outline of the bulky yarn for tension cutting obtained by the present invention is that fiber portions drawn to various ratios are randomly formed, and there are extremely few portions that remain completely undrawn.

This is because, in the present invention, the heating element humidity condition in the heating zone is extremely high, exceeding the crystallization humidity.

That is, in the case of a temperature condition lower than the above temperature, a portion with an intermediate thickness is hardly formed, and a preferable randomness cannot be obtained.

Furthermore, the elongation at break is generally small, and rarely exceeds about 35 modulus.

In other words. Because it is drawn at a high temperature, the parts where the drawing ratio is low are still lowly oriented and crystallized, making them brittle, and because they are random, it is rare for each filament to break at the same time during stretching, and the maximum tension is low. Moreover, the elongation at maximum tension is also low.

From these facts, in order to obtain a bulky yarn for tension cutting by the method of the present invention, the draw ratio, temperature of the heating element, shape of the heating element, and contact time to the heating element are important;
The temperature of the heating element is above the crystallization temperature of the fiber, and the shape of the heating element is better to avoid fixing the stretching start point, so as mentioned above, it is better to use a flat heating plate rather than wrapping it around a heating pin or heating roll, and to avoid contact with the heating element. It is desirable that the heating time be 0.1 seconds or less so that each fiber is not subjected to uniform heat treatment.

In addition, the pitch and randomness of the undrawn yarn portion can be adjusted freely by changing the stretching ratio and the humidity of the heating element.
When the humidity of the heating element is increased, the pitch in the undrawn part becomes finer and the degree of randomness becomes smaller, which reduces the variation in the strength and elongation of each single fiber, making it suitable for processing fine denier yarns that do not require large tension cutting forces. Or it can be organized as is.

On the other hand, if the stretching ratio is small and the heating element temperature is extremely high or low, the pitch of the unstretched part will be large and the degree of randomness will be high, making it suitable for processing thick denier yarns that require a large tension cutting force.

The effects of the present invention are as follows.

Bulky yarn for stretch cutting can be produced using a simple method and device.

Since it can be manufactured in one step using polyester-based undrawn multi-filament yarn, the manufacturing cost is low.

The multi-filament yarn obtained in the present invention can be cut into simple leather, and at the same time, when subjected to relaxing heat treatment, shrinkage occurs due to the difference in heat shrinkage between each prefecture fiber and in the fiber length direction, resulting in bulkiness.

Moreover, when the yarn is dyed, it becomes a marbled-like yarn due to dyeing differences due to random drawing unevenness, so even if it is knitted and woven as is without stretching, it is bulkier than a fabric using ordinary drawn yarn and has a spun yarn-like appearance. Creates a dyeing effect.

In addition, since the temperature of the heating element is higher than the crystallization temperature of the fiber,
Thermal shrinkage rates such as boiling yield and dry yield of the multifilament yarn as a whole are equal to or lower than that of ordinary drawn yarn, and when made into fabric, it has excellent dimensional stability due to heat during dyeing and finishing.

The bulky yarn for stretch cutting according to the present invention is suitable for use in knitting and fabrics for general clothing.

Example 1 Polyester was spun at high speed to obtain a birefringence of 18×10-3
An undrawn multifilament yarn having a thickness of 176.6 denier and 36 constituent leather fibers was obtained.

Next, the bulky yarn for tension cutting of the present invention was produced using the apparatus shown in FIG. 1, and wound around cheese 7.

Thereafter, as shown in FIG. 2, the multi-filament yarn Y is pulled out from the cheese 7 on which the yarn of the present invention has been wound, is cut between the feed roller 8 and the delivery roller 90, and then twisted by the yarn twisting device 10 while being attached to the bobbin 11. rolled up.

Compared to conventional spun yarns, the finished yarn had a more even and glossy appearance, and had a good texture when knitted into a fabric.

The processing conditions are as follows.

Stretching ratio: 1.95 (2.30 @ during normal stretching) Hot plate immersion: 150C Hot plate touch time: 0.06 seconds Delivery roller speed: 300 n/min Draft rate of tension cutting process: 1.45 times carried out Example 2 Polyester was spun at high speed to obtain an undrawn multifilament yarn having a birefringence of 20×10 3 , a thickness of 154 denier, and a triangular cross section of 36 constituent fibers.

Next, the bulky yarn for tension cutting of the present invention was obtained using the apparatus shown in FIG.

The characteristic values of the yarn are shown in Table 1. The yarn of the present invention has a higher bulk than the normally commercially available drawn yarn, and also has a low boiling water shrinkage rate (boiling yield), resulting in low shrinkage and high bulk. It's a thread.

When this multi-filament yarn is knitted without tension cutting and the knitted fabric is dyed, dots or linear shading areas appear on the surface of the knitted fabric, giving it a spun yarn-like color tone and a silk-like luster. The result is a soft and bulky knitted fabric.

The processing conditions are as follows.

Stretching ratio: 1.90 (2.05 times during normal stretching) Hot plate humidity: 150C Hot plate touch time: 0.06 seconds Delivery roller speed: 300 m/min Yarn properties were measured by the following measuring method.

Bulk level: 5 pieces in total of 80 turns of yarn to be measured are collected and subjected to relaxation heat treatment (200°C x 5 minutes).

Align the sample in parallel, fold it into four, and put 2.5 mm on the side.
Place cr width tape and weigh 50g of both lower ends together.
Apply lateral pressure with a load of

The ratio of the volume and weight of the yarn bundle surrounded by the tape at this time was expressed as yarn bulk height.

Boiling yield: The yarn plan to be measured has a total of 10 turns, the total length before hot water treatment, and the total length 1 after hot water treatment at 98°C for 30 minutes, and the length is read under a load of 0.1 g/d.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing one embodiment of the present invention. FIG. 2 is a schematic diagram showing an embodiment of a device for tension cutting bulky yarn for tension cutting according to the present invention. FIG. 3 is a load-elongation curve of the polyester undrawn multifilament yarn used in the present invention. FIG. 4 is an enlarged view of the fibers of the yarn obtained according to the present invention, in which a shows the netting part and b shows the unstretched part. FIG. 5 shows the load-elongation curve of each single fiber of the yarn obtained by the invention. FIG. 6 shows a state in which the yarn obtained according to the present invention has been subjected to relaxation heat treatment. 1... Supply package, 2... Pretensor, 3...
... Feed roller, 4... Hot plate, 5... Delivery roller, 6... Winding mouth roller, 7... Rolling cheese, 8... Feed roller for tension cutting, 9... For tension cutting Delivery roller, 10... Twisted yarn winding device, 11...
Winding bobbin. Y: polyester undrawn multi-filament yarn, Y:
Bulky thread for bulk cutting, which is advantageous in the present invention.

Claims (1)

[Scope of Claims] 1. Polyester undrawn multifilament yarn having a birefringence Δn of (15×10−3)<Δn×(80×10−3) that is continuously supplied is placed in a heating zone where a heating element is arranged. When heating and stretching the fiber, the humidity of the heating body is set to be higher than the crystallization temperature of the fiber, the stretching ratio is lower than the natural stretching ratio, and the stretching is carried out so that substantially no contracted portion is included. A method for producing bulky yarn.