JPS6088147A - Production of blended thich and thin fiber yarn - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a thick and fine mixed yarn made of thermoplastic multifilament. More specifically, the ratio of the average denier of the yarn group with the thinnest single yarn denier to the average denier of the yarn group with the thickest single yarn denier is 2.0 or more. The purpose of the present invention is to provide a method for stably producing high-quality thick/fine mixed fiber yarns without forming loops in the drawn thick/fine mixed fiber yarns.

Conventionally, methods for producing mixed fiber yarns include combining filaments of different fineness in each process, or using a spinneret with discharge holes of different sizes on the same spinneret surface, starting from the melt-spinning stage. Methods of making mixed yarns are known. However, all of these methods have the problem that thick single fibers tend to form loops after drawing, and especially thick and thin fibers where the ratio of the minimum single yarn denier to the maximum single yarn denier is 2.0 or more. This tendency is remarkable for combinations with large ratios. As a result, yarn breakage occurs when unraveling the drawn yarn, and the thread passability during the false twisting process, weaving process, etc. is significantly deteriorated, resulting in decreased operability and quality deterioration due to single yarn breakage or whole yarn breakage. However, a solution has not yet been provided. Therefore, as a means to avoid these problems, a method of doubling yarns on the high-order processing side, that is, in the false twisting process or the weaving process rather than in the drawing process, is generally practiced more frequently. However, gold thread used in high-level processing is more expensive than gold thread used in the drawing and spinning processes, and the mixed fiber state of mixed fiber yarns tends to be uneven between yarns, resulting in a decrease in the quality of mixed fiber yarns. It has a decisive drawback.

In view of the problems of the prior art as described above, the object of the present invention is to draw undrawn thick and fine mixed fiber yarns in which the ratio of the minimum single yarn denier to the maximum single yarn denier is 2.0 or more. However, it is an object of the present invention to provide a method for producing a thick and fine mixed fiber yarn that does not cause loop-like lumi to occur in the thick single fibers after drawing.

The present invention achieves the above object, when drawing a thick and fine mixed fiber undrawn yarn in which the ratio of the minimum average single yarn denier D1 to the maximum average single yarn denier D0 is 2.0 or more, the mixed fiber undrawn yarn is The drawn yarn is made in such a way that the average elongation difference between the undrawn yarn group with the minimum average single yarn denier and the undrawn yarn group with the maximum average single yarn denier is 120% or less, and the difference in drawing tension is 0.5 g/d or less. The present invention is characterized in that the mixed fiber undrawn yarn is drawn using heated drawing pins or heated rotating rollers.

The mixed fiber yarn of the present invention is made of a thermoplastic polymer such as polyester, polyamide, or polyolefin, and is a mixture of two or more filament groups of different deniers. The mixed fiber undrawn yarn before drawing has the smallest average single yarn denier D1 and the largest average single yarn denier D among the constituent filament groups. The target is those with a ratio of 2.0 or more. Such mixed fiber undrawn yarns may be obtained directly from the same spinneret during the spinning process, or they may be spun in separate spinning processes and mixed together before the drawing process. .

゛The characteristic requirements that such a mixed fiber undrawn yarn should have are that the difference in average elongation between the undrawn yarn group with the minimum average single filament denier and the undrawn yarn group with the maximum average single filament denier is 120% or less; In addition, it is necessary that the stretching tension difference is 5 g/d or less.

As shown in FIG. 1, the loop-shaped walnut in which the mixed fiber yarn is generated after drawing may be formed on the surface of the drawn yarn pirn 20 as a large number of loop-shaped walnuts 21. Although there is no loop-like sag on the surface like the drawn yarn pirn 22 shown in the figure, there is also a loop-like sag 23 that occurs when the mixed yarn is released. The reason why a drawn blended yarn produces loop-like curls is that the instantaneous shrinkage rates immediately after drawing are different between the threads of different fineness that make up the blended yarn. Making the difference in rate as small as possible will suppress the generation of loop-like luminescence. On the other hand, the relationship between the elongation difference of undrawn yarns and the number of loop-shaped walnuts is shown in FIG. 3, and the larger the elongation difference, the more walnuts occur. The relationship between the difference in stretching tension and the number of loop-shaped walnuts is shown in FIG. 4, and it can be seen that the larger the difference in stretching tension, the more walnuts there are.

As a result of considering reducing the difference in instantaneous shrinkage rates from this point of view, the present inventors have determined that the elongation of undrawn yarn is the average elongation E, (%) of the yarn group with the thinnest single yarn denier. E is the average elongation of the thickest yarn group. (The difference (En-El) from the drawing system should be 120% or less, preferably 100 inches or less, more preferably 70 coefficients or less, and the drawing tension during drawing should be the yarn group with the thinnest single filament denier. The stretching tension T1 (
g/d) and the drawing tension Tn (g/d) of the thickest yarn group (TI-T,) is o, sg/d or less, preferably 0.
．． It has been found that it is necessary to use undrawn yarn whose fiber density is controlled to be 3 g/d or less. The above average elongation difference and stretching tension difference are each 120 inches or less, o, s
A specific method for obtaining an undrawn yarn whose g/c+ is controlled to be less than or equal to g/c+ is as follows. When producing mixed fiber yarn using the same spinneret in the spinning process, the discharge hole array on the spinneret surface is arranged so that the outlet hole group that discharges the smallest denier yarn is placed closest to the cooling air blowing surface, and The nozzle is arranged in parallel blocks to form a group of discharge holes for discharging denier yarn, and the temperature of the cooling air is 15 to 30°C, and the +1st speed is 15°C.
It is effective to cool and wind with a steady flow controlled within the range of ±2 m/mm at ~40 m/7.

In this case, if the mixed fiber undrawn yarn has a large difference in fineness such that the ratio of the maximum average single yarn denier to the minimum average single yarn denier is 3.0 or more, the group of thick denier undrawn yarns has an irregular yarn cross-sectional shape. It is effective to use a shear force or a hollow cross section. In addition, when undrawn yarns spun in separate spinning processes are pulled together in a yarn guide process before the drawing zone in the drawing process to form a mixed yarn, the spinning speed of each spinning process is adjusted to the single yarn denier. It is effective to adjust the speed in the direction of increasing the thickness.

Furthermore, in the present invention, it is necessary to use heated drawing pins or heated rotating rollers for drawing.

In the case of heated stretching pins, the stretching pin diameter is 15 to 40 mm,
It is desirable that the surface temperature of the stretching pin be 90 to 140'C, and the film is wound around the stretching pin once or twice so that a tension gradient is applied before and after the stretching pin for stretching. In the case of heated rotating rollers, it is desirable to heat them to a surface temperature of 75 to 105°C, and after running in contact with the rotating roller for 0.04 seconds or more, there is Stretch at an appropriate magnification.

Furthermore, after the yarn is preheated by the heated rotating roller, it may be stretched by winding it around the stretching pin once or twice and then stretching it. The drawn yarn may be wound into paan or cheese without being heat-treated, or may be heat-treated using a hot plate or heated rotating roller, and then wound into paan or cheese.

FIG. 5 shows an example of the above-described method of the present invention in which undrawn yarns A, B, and C of different fineness obtained in separate spinning steps are combined and drawn before the drawing step. .

In FIG. 5, each of the undrawn yarns A, B, and C pulled out from the drum are converged by a yarn path regulating guide 1 into one thick and fine mixed fiber undrawn yarn 2, which is made of an elastic material and is The speed is regulated by a roller 3 and a metal roller 4 that rotates at a constant speed. After that, it is preheated by a heated rotating roller 5, and then heated and stretched by a heated drawing pin 6.
It is wound once or twice, heat-treated on a hot plate 7, and guided to a rotating roller 8. The peripheral speed ratio of rollers 4 and 5 is 0.3 to 2.
Thread path stability is better if the stretching state is set within the range of 0. The peripheral speeds of the rows 24 and 8 determine the drawing ratio, and are set to an appropriate ratio depending on the quality of the undrawn yarn.

After passing through the rotating roller 8, the thick and fine mixed yarn passes through the yarn path regulation guide 9.
After passing through the balloon, the balloon is rolled up onto a pirn 10 while drawing the balloon to complete the stretching process.

The thick and fine mixed fiber yarn produced as described above is a blended undrawn yarn having a ratio of minimum average single yarn denier to maximum average single yarn denier of 2.0 or more, but does not form a loop shape. Lumi will not occur. This will be explained in detail below using examples.

In addition, in the examples, the loop-shaped sag measurement was performed at trial 50.
This is a method in which a load of 0.5 g/d is gently applied to a sample of Crn, allowed to stand for 1 minute, and then relaxed, and the walnuts produced are measured with the naked eye.The average value of each measurement of 20 or more times is calculated in units of [ke/m]. This is what is displayed.

Example A polyethylene terephthalate chip containing Q, 5 wt% titanium oxide with an intrinsic viscosity of 0.66 was discharged with a number of holes of 36 H.
, 24H and 12I (spinning temperature 29
After melt spinning at 5°C, cold air (20°C, 930 m/m
The fibers were cooled at a temperature of 100.degree. in) and spun at various take-up speeds. The resulting undrawn yarns were combined to form a mixed yarn configuration as shown in the attached table, and using the drawing device shown in Figure 9, the drawing ratio was 3.0 times and the drawing speed was 350''/min. Temperature 85°C1 Stretching pin diameter 20mmφ,
Stretching was carried out at a stretching pin surface temperature of 125°C and a hot plate temperature of 120°C. Furthermore, the obtained drawn yarn was subjected to a false twisting process.

In the attached table, in Experiments 41.2 and 3, the difference in elongation and the difference in drawing tension of the undrawn yarns were within the most desirable range of the present invention, so there was almost no occurrence of loop-shaped curling. Therefore, there was almost no yarn breakage during the false twisting process, and a thick and fine mixed yarn having good textile quality was obtained. In Experiments 164 and 5, the difference in elongation and the difference in stretching tension between the undrawn yarns became quite large, resulting in an increase in loop-like lumi and an increase in yarn breakage during false twisting. The textile quality of the yarn was good. On the other hand, in Experiment I66, both the elongation of the undrawn yarn and the difference in drawing tension were outside the range of the present invention.
There was a sudden increase in loop-like Rumi. Therefore, the number of yarn breakages during false twisting increased, and the fabric quality of the obtained thick and fine mixed yarn was also poor.

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[Brief explanation of drawings]

Figures 1 and 2 are front views showing drawn yarn pirns that have generated loop-shaped curls, Figure 3 is a diagram showing the relationship between the elongation difference in undrawn yarns and loop-shaped curls, and Figure 4 is a diagram showing the relationship between the elongation difference in undrawn yarn and loop-shaped curls. FIG. 5 is a diagram showing the relationship between the tension difference and the loop shape, and is a schematic diagram showing an example of a stretching process for carrying out the present invention. A, B, C... undrawn yarn, 5... heating rotating roller,
6...Heating stretching pin, 8...Rotating roller. Agent: Patent attorney Makoto Ogawa − Patent attorney: Ken Noguchi Patent attorney: Kazuhiko Saishita (13)

Claims (1)

[Claims] Minimum average single yarn denier D1 and maximum average single yarn denier D. When drawing a thick and fine mixed fiber undrawn yarn having a ratio of 2.0 or more, the mixed fiber undrawn yarn is divided into an undrawn yarn group having a minimum average single yarn denier and an undrawn yarn group having a maximum average single yarn denier. The average elongation difference is 120 modulus or less, and the stretching tension difference is 0.5
g/d or less, and the method for producing a thick and fine mixed yarn is characterized in that the undrawn mixed yarn is drawn using a heated drawing pin or a heated rotating roller.