JPS595683B2 - Method for drawing differentially shrinkable mixed fiber yarn - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for drawing a mixed yarn consisting of yarns with different shrinkage rates, and more specifically, a method for drawing a multifilament in which yarns with different shrinkage rates are mixed. The present invention relates to a method of operating a draw-twisting machine when stopping and when starting drawing.

Multifilament, which is composed of two or more yarns with different shrinkage ratios, so-called different shrinkage mixed yarns, has recently become very popular as a high value-added yarn that significantly improves the appearance, texture, bulkiness, and other properties of woven and knitted fabrics. Attention has been paid.

As a method for obtaining a mixed fiber yarn in which the single yarns constituting the multifilament have different shrinkage rates, the following methods are generally used depending on the manufacturing process.

(1) Spinning and blending method: A method in which two or more polymer melts designed to have different shrinkage rates of the yarn after drawing are spun from different discharge holes, simultaneously wound up, and then subjected to drawing treatment. .

(2) Stretching and blending method: Two or more types of undrawn yarns with different shrinkage rates are simultaneously drawn and combined, or undrawn yarns of the same type are added to the drawing process to eliminate differences in shrinkage rates. A method in which the yarns are subjected to different treatments such that they occur, and then the yarns are doubled.

(3) Post-process blending method: A method of blending two or more drawn yarns with different shrinkage rates by opening and mixing them with each other.

Among these methods, the first or second method is more advantageous than the third method because it allows the yarn to be made into a mixed yarn without going through the mixing step again. When mixing fibers, it is necessary to wind up multifilaments made of yarns with different shrinkage rates in a drawing process, generally using a draw-twisting machine.

In addition, in the operation of the drawn and twisted yarn machine, in order to save labor and reduce yarn loss when threading, the amount of undrawn yarn is increased and many drawn yarns are dotted on the same undrawn yarn spool area. This method is particularly efficient when several undrawn yarns are combined by drawing, such as a drawn mixed yarn.

When dotting the drawn yarn, the ring is lowered to the waist bobbin position to perform dotting, and then restarting in this state allows continuous dotting without the need for threading. It has become.

When using this method of operating a draw-twisting machine to obtain yarns with different shrinkage rates, the winding section and the final roller must be connected between stopping the draw-twisting machine and restarting it. The multifilaments between the two are left untensioned, causing contraction when the strain in the filament structure received during drawing is resolved.

Since the amount of shrinkage differs depending on the degree of heat setting, some of the threads in the multifilament may become slack, and when the multifilament is restarted, this slack may be caught on the traveler, causing the thread to break or the traveler. It has been found that undesirable phenomena such as the scattering of substances occur.

This phenomenon is particularly likely to occur when drawing mixed fiber yarns that have yarns with different shrinkage rates that are easy to split. Therefore, as a countermeasure, it is necessary to draw yarns with different shrinkage rates as uniformly as possible. Methods are being considered, such as mixing them with other materials, or actively entangling and converging them using an air jet or the like.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for solving these problems while maintaining the characteristic that yarns having different shrinkage rates are easy to split and without reducing work efficiency.

That is, when winding up a mixed yarn of two or more yarns with different dry heat shrinkage rates of 5 factors or more at 120° C. using a draw-twisting machine, the present invention provides a method for rolling up a final roller that reaches the winding section when the draw-twisting machine is stopped. and then stop the rotation of the spindle,
This is a method of drawing a differentially shrinkable mixed fiber yarn, which is characterized in that the yarn from the final roller to the winding section is twisted to a degree of 50 T/M or more, and then drawing is restarted.

The present invention is a method for drawing a mixed yarn composed of two or more yarns having dry heat shrinkage rates at 120°C that differ by 5% or more. In some cases, since the slack is small, the above-mentioned problem does not occur.

In the present invention, it is essential that the yarn from the final roller of the drawing path 'rfRj4 IC to the winding section is twisted with a twist of 50 T/IVI or more.

That is, by twisting the yarn at the end of the stretching, the slack of the already laid yarn until the stretching is restarted is suppressed, and the stretching can be resumed smoothly.

In this case, if the number of twists at the end of stretching is less than 50 T/M, it is not preferable because the occurrence of sagging until the start of stretching cannot be sufficiently suppressed.

When restarting stretching, it is possible to start the rotation of the spindle and the rotation of the final roller at the same time, but even in this case, by rotating the spindle before the rotation of the final roller, it is possible to twist the edges even more. It is preferable to do so.

Furthermore, in the mixed fiber yarn to be drawn by the drawing method of the present invention, at least one of the two or more yarns having different shrinkage rates is a yarn made of polyethylene terephthalate (polyethylene terephthalate) or a copolyester containing polyethylene terephthalate as a main component. It is preferable that there be.

The present invention will be explained in detail with reference to the drawings below.

FIG. 1 is a simplified diagram of a draw-twisting machine showing an example of an embodiment for explaining the present invention in detail.

The yarns Y, Y' are pulled out from the undrawn packages 1, 1' wound around the bobbins 2, 2', passed through the guides 3, 3', and then fed to the supply rollers 4, 4' and their separate rollers 5.
.
After winding the yarn around the separate roller 7 and drawing and doubling it, the yarn is wound onto a bobbin 12 via a traveler 11 attached to a ring 10 of a rabbet guide 9.

The bobbin 12 and the west bobbin 14 are connected to the spindle 13
The spindle 13 is driven via a belt 15.

When stopping the draw-twisting machine after a predetermined amount of drawing is completed,
After lowering the ring 10 to the position of the waist bobbin 14, as shown in FIG. 11 can be twisted.

Similarly, at the start of stretching, as shown in FIG. 2B, the rotation of the spindle is made earlier than the rotation of the rollers by Ts (seconds), and the desired twist can be applied to start.

Conventionally, as shown in Figure 2A, the rotation of the spindle and the rotation of the rollers were started and stopped at the same time at the start and stop of drawing, so the drawing and twisting machine was stopped as described above and then restarted. By this time, the multifilament between the winding part and the final roller is left untensioned, causing contraction to eliminate the strain in the yarn structure received during drawing, and the amount of shrinkage reaches the level of heat setting. Due to the difference in texture, some of the threads in the multifilament would become slack, causing the threads to break or cause the traveler to fly off when the multifilament was restarted.

The effects of the present invention will be explained in detail with reference to Examples.

Example 1 Polyethylene terephthalate having an intrinsic viscosity [η,] of 0.65 was melt-spun and wound at 1200 m/min.
5Den/24 f i l undrawn yarn bobbins 2 pcs.
The set was simultaneously drawn using the apparatus shown in FIG. 1 at a drawing ratio of 3.0, a drawing speed of 600 rrlArLi, and a surface temperature of 80° C. of the supply rollers 4 and 4', with one of the threads being brought into contact with the heating plate 8. The yarn was combined with the other yarn that had not been heat-treated and wound up.

At the end of the stretching, the timing of stopping the rotation of the rollers and stopping the spinning was changed and stopped.

Five minutes after stopping, the slack state and number of twists of the yarn in the roller and winding section were measured, and in this state, stretching was restarted to control the yarn breakage rate.

When stretching was resumed, the spindle and rollers were synchronized and started at the same time.

These results are shown in Table 1.

In Table 1, Test A(1) A3) is an example.
), (4)-force indicates a comparative example.

Example 2 Two undrawn yarns identical to those in Example 1 were drawn at a drawing ratio of 3.0, at a supply roller temperature of 80°C, a hot plate temperature of 190'C, and a drawing speed of 60°C.
At 0 m/min, one yarn is brought into contact with a hot plate and the other yarn is not brought into contact with each other, and when the yarn is doubled and stretched using a take-up roller, the following operations are performed at the end of stretching and at the beginning of stretching. The fibers were stretched and yarn breakage was measured when stretching was resumed.

The results are shown in Table 2.

The high shrinkage yarn had a 120''C# heat shrinkage rate of 13.5%, the dry heat shrinkage rate of the low shrinkage yarn was 5.2%, and the difference in shrinkage rate was 8.3%.

(1) When the twisting machine is stopped, the spindle should be stopped for 7
Twisting was applied at 0T/M, and the spindle was rotated first at startup to apply twisting.

(2) When stopping, the conventional method was used to stop at the same time, and when starting, the spindle was rotated in advance and twisting was applied.

(3) Same as above (4) At the time of stopping and starting, the spindle and roller were synchronized to stop and start at the same time.

[Brief explanation of drawings]

FIG. 1 is a simplified diagram of a draw-twisting machine illustrating an embodiment of the present invention. Figure 2 shows the relationship between the spindle rotational speed and roller rotational speed at the time of starting and stopping stretching to explain the present invention; Figure 2A shows the conventional method, and Figures 2B and C show the invention. It is by law. Y, Y'... Yarn, 4, 4'... Supply roller, 6... Take-up roller, 8...
・Heat treatment equipment, 13... Spindle

Claims (1)

[Claims] When winding up a mixed yarn of two or more yarns with different dry heat shrinkage rates of 5% or more at 1120°C using a draw-twisting machine, when the draw-twisting machine stops, the final A different method characterized by stopping the rollers, then stopping the rotation of the spindle, applying a twist of 50 T/M or more to the yarn from the final roller to the winding part, and then restarting the drawing. Method for drawing shrink blended yarn. 2. Differential contraction according to claim 1, in which the yarn from the final roller to the winding section is further twisted by starting the rotation of the spindle and then starting the rotation of the final roller when restarting the stretching. Method of drawing mixed fiber yarn. 3 At least one of two or more yarns with different shrinkage rates
2. The method for drawing a differentially shrinkable mixed fiber yarn according to claim 1, wherein the yarn is made of polyethylene terephthalate or a copolyester containing polyethylene terephthalate as a main component.