JPS58163721A - Production of unevenly drawn yarn - Google Patents

Abstract

PURPOSE:A polyester undrawn yarn of a specific optical birefringence is stood under specific conditions, drawn in a heated atmosphere and heat set under drawing-free conditions to produce an unevenly drawn yarn giving grandrell yarn-like patterns with large difference in color thickness and less fluff formation. CONSTITUTION:A polyester undrawn yarn of 0.10-0.035 optical birefringence is stood at 20-30 deg.C for longer than 20hr and drawn at a draw ratio of 60-75% of the maximum in a hot atmosphere at a temperature lower than 70 deg.C. The resultant yarn is heat set at 90-120 deg.C under such conditions as of 0.990 draw ratio to substantially undrawing ones to produce the objective uneven yarn with grandrell yarn-like patterns and less than 8 U% according to the eveness tester. The heat setting after drawing is preferably carried out at a draw ratio of 0.995-1.000.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a mottled drawn yarn exhibiting a heathered i- tone, and in particular, it has good processability with a noticeable difference in shade of wilting and streaks, and less fluffing due to drawing mottling. This invention relates to a method for producing a good unevenly drawn yarn.

Items such as:

■If the stretching ratio is lowered or the heat treatment temperature is lowered in order to emphasize the difference in dyeing shading, the unstretched part becomes brittle, prone to fluffing and yarn breakage, and has low heat resistance. □In order to provide physical properties that can withstand tough swimming and drying heat treatment, if the second stretching ratio is particularly increased or the heat treatment temperature is increased, the difference in dyeing shading will not only be small (1), but the dark color pattern will become longer and fluffier. There are many occurrences.

These conflicting required characteristics were determined by #L quality (as a result of intensive study by the present inventors, the length of the dark and light color areas is relatively short, the length of the dark color part and the light color part is relatively short, and the length of the dark color part and the light color part is significant, and the thread breakage is very short. We have now obtained a low-shrinkage unevenly drawn yarn that has very little occurrence of fuzz and fluff, and can be used satisfactorily in steam yarn as a highly twisted yarn.

That is, in the present invention, the birefringence index (Δn) is in the range of o, ota to o, ois. Once the black I polyester undrawn yarn is left at 20°C to SO°C for more than ζ2o hours, it is heated to 70°C or less. The maximum stretching ratio is 60~ using a heating element of
It is drawn at 75% and then heat treated at 90°C to 120°C under conditions of 0.990 times or more of the drawn yarn to substantially no drawing, so that 6% as determined by an evenness tester becomes 8%. The object is to obtain a mottled drawn yarn having the following heathered pattern.

The heat of the present invention will be described in detail below, but first, when using a low-oriented undrawn yarn whose birefringence index is lower than 0.010, the drawn yarn has a clear difference in dyeing shading. However, fuzzing and yarn breakage occur frequently, the dyeing machine's dark-colored section collapses, and even after fabric is made from this yarn, there are holes in some areas. On the other hand, when an undrawn yarn with a birefringence exceeding o or oss is used, a drawn yarn with good process passability and physical properties can be obtained, but it is not preferable because the difference in dyeing density is poor. However, if an undrawn yarn with a birefringence that falls within this range is used, there will be a clear difference in dyeing shading, and even if the yarn wound around a bobbin after strong twisting is steam bonded, there will be differences in the yarn physical properties between the inner and outer layers of the bobbin. is small, and even if the ξ yarn is treated with alkali, a partially drawn yarn can be obtained that can sufficiently withstand heat ζ.

By the way, when undrawn polyester yarn immediately after spinning is wound onto a take-up bobbin, there is a significant difference in the natural stretching area between the inner and outer layers of the bobbin, and this yarn is immediately heated to When partially stretched at a certain magnification, the heathered pattern of the resulting yarn is
It is noticeable between the outer layer yarn and inner layer yarn of the bobbin. That is,
In the undrawn yarn of the outer layer of the bobbin, the dark and light dyed parts, that is, the thick undrawn parts and the thin stretched parts, tend to become elongated, and the U% value becomes high, and the physical property difference in the length direction of the yarn becomes clear.

However, prior to low-magnification stretching, this winding bobbin was
By leaving the yarn in a storage room at a temperature between ℃ and 30℃ for a certain period of time, the difference between the inner and outer layers of the yarn wound on the bobbin becomes smaller, and the outer layer yarn changes over time into an undrawn yarn with yarn characteristics similar to the inner layer yarn. do. As the yarn changes over time, many cracks occur in the thread during stretching, resulting in a large number of stretching points, which shortens the length of the dark and light dyed areas and stabilizes the physical properties.

As a result, the U% exhibits a relatively low value of 8% or less for a unevenly drawn yarn. As described above, the greatest finding of the present invention is to leave the film at a specific temperature for a certain period of time before stretching at a low magnification.

Now, when this undrawn polyester yarn is left to stand immediately after spinning, there is little change in the physical properties of the inner and outer layers of the yarn at temperatures below 20°C even if it is left for several days, and at temperatures exceeding sO°C, the physical properties of the yarn in the inner and outer layers of the bobbin change. Rather than approximating it, it changes rapidly over time while expanding.

Therefore, in the present invention, the difference in physical properties of the yarn between the inner and outer layers of the bobbin is reduced by leaving the yarn in a room at a temperature in the range of 20° C. to sO° C. and standard humidity for 20 hours or more.

In the present invention, when the undrawn polyester yarn of the winding bobbin that has been left at a relatively low temperature for 20 hours or more is then drawn at a low magnification, the temperature of the heating element (heating atmosphere) in the drawing section exceeds 70°C. In this case, there are few thick unstretched parts that become dark dyed parts (at 80°C or higher, thick parts do not appear and the stretched parts are uniformly stretched).
It is necessary to keep the temperature below 0°C. The drawing ratio in ξξ is 60, which is the maximum drawing ratio of undrawn yarn, which is higher than that of the general number ζ developed unevenly drawn yarn.
7s%, and this is suitable for the present invention. The reason for this is that in order to stretch the undrawn yarn at a low temperature after aging the undrawn yarn appropriately, the stretched and undrawn portions are clearly dispersed and appropriately short in the length direction, and it is necessary to carry out further drawing as described below. Since there is no ξ, the stretching ratio in the second direction can be relatively high, and the physical properties of the second part can also be improved. ξThe maximum drawing ratio of undrawn yarn is the following empirical formula! This is obtained by ζ.

Maximum drawing ratio - ((Elongation of undrawn yarn + 100) 7100
) Xl, 05 If the stretching ratio t of the present invention is less than 60% of the maximum stretching ratio, the dark colored part is likely to become elongated, and only a yarn with large heat shrinkage and unstable physical properties can be obtained. At a stretching ratio exceeding ys9/6, it becomes difficult for dark and light brass to appear even if the temperature of the heating element is as low as possible.Therefore, by using a heating element (heating atmosphere) at a temperature of 7°C or less, the maximum stretching ratio is By setting the stretching ratio to 60 to 75%, it is possible to obtain speckled yarns with suppressed elongation of dark and light colored areas without performing two-stage stretching.

However, unevenly drawn yarn drawn under such conditions has poor thermal stability as it is because the drawing temperature is low, so it is necessary to further heat set it, and this heat setting process is used to form the final drawn yarn. The thermal properties are determined. According to the findings of the present inventors, by drawing the undrawn yarn that has been aged in advance over time before drawing as in the present invention at a maximum draw ratio of 60% to 7s%, even heat treatment at a relatively low temperature can be applied. A yarn with stable thermal properties is obtained. Generally speaking, it is a matter of course that a yarn can be thermally stabilized if it is heat treated at the highest possible temperature, but in the present invention, the yarn subjected to heat treatment is a partially irregularly drawn yarn that is unevenly drawn in the longitudinal direction of the yarn. Therefore, loop fuzz is likely to occur. The occurrence of loop fuzz tends to occur more frequently as the degree of heat setting mmm increases. The present inventors have conducted various studies to resolve the contradictory required characteristics of high temperature to obtain thermal stability of the yarn and low humidity to suppress the generation of loop fluff, and as a result, the present invention has already been developed. Using the above-mentioned undrawn yarn, after unevenly stretching it, the yarn length is 0.990 times to 0.9 times the yarn length, preferably 0.9?
By processing at a relatively low heat setting temperature of 90 DEG C. to 125 DEG C. at a magnification of 5 times to 1.000 times, a unevenly drawn yarn of 1 DEG with stable thermal number ζ and less fuzz was obtained. ξ At this point, stretching is substantially carried out during heat setting, and the yarn lengths o, t
If the yarn is less than t0 times (a state in which the yarn is slack), loop fuzz tends to occur frequently.In particular, when the yarn is slack, the yarn winds around the roller, making heat fixation impossible. the result,
It becomes necessary to increase the heat setting temperature to a higher temperature, which further increases the occurrence of loop fuzz. Therefore, the heat fixing temperature of 90°C to 125°C under the condition of neither substantial stretching nor substantial relaxation in the present inventor's ζ is suitable. Sumi ink has poor elasticity and has large thermal shrinkage and elongation. On the other hand, at temperatures exceeding 125° C., loop fuzz suddenly occurs frequently.

The unevenly drawn yarn that has been drawn and heat-set in this way exhibits a relatively short shaded, light and grainy cross-like shape with a U96 of s4 or less according to the Evenness tester cloud ζ, and its physical properties are significantly different from ordinary drawn yarns. Heat shrinkage - ζ and steam set ζ of strongly twisted yarn also yield heathered drawn yarn suitable (boiling water shrinkage rate ~15%). It is characterized by the fact that the undrawn yarn produces clearly drawn and undrawn parts, and that these can be heat-set without performing two-step drawing, and the physical properties are stable even though the difference in dyeing shading is clear. It has few defects such as loop fuzz and has excellent heat resistance and alkali resistance.

Mlζ and inventor ζ will be specifically explained along with comparative examples. The outline of the yarn evaluation method is as follows.

Judgment of number of loop fuzz 1 o 6# per winding pirn surface Number of loop fuzz from 0 to 10 △ 4- Singing 1-
sOke 4-× evening s1
Measuring the heat shrinkage rate of a thread in boiling water for 10 or more months
Shrinkage rate (%) when immersed for minutes U%: U% from the outermost layer to the innermost layer of the bobbin (all properties; yarn speed 25ml 1 min, Fall Meals t O05
4) (Evaluation of D change & pattern and its bobbin inner and outer knitted fabric with inner eye) Example 1 The birefringence of the 49 ester non-drawn yarn immediately after spinning was 0.
015, the maximum stretching ratio is approximately S, S times 200 dr/l
Using a yarn of 6 f, unevenly drawn yarn was obtained under the conditions listed in Table 111 below (however, the stretching speed was 700 m and 7 minutes).As is clear from the results in Table 1, the present invention was carried out. Example Mu~J
So, is the pattern short?
% was less than $96, and yarns with an overall rating of ◎ to 0 were obtained, whereas in Comparative Examples M to J, the patterns were generally long (the number of patterns was small), there was a lot of fluff, and the overall evaluation was ◎ to 0. Only large yarns (millk total evaluation ×) were obtained. As this result shows, ΔnO,015 immediately after spinning
The undrawn polyester yarn was heated at 20-50℃ for 20 minutes.
Leaving for more than an hour, and then stretching in a heated atmosphere of 70°C or less (ordinary temperature is also possible) at a maximum stretching ratio of the undrawn yarn (approximately i, s times in this example) in the range of 60 to 754; Finally, heat constant at 90-125℃, 0.990 times ~
Conditions (specifically, 1,01
0 times is the upper limit), and depending on the number ζ, a heathered pattern yarn having the desired yarn physical properties can be obtained. It is clear that even if any of these conditions is removed, the yarn targeted by the present invention cannot be obtained.

Example 2 An experiment similar to the previous example was carried out using undrawn ester yarn with a birefringence index of 0.025 (maximum drawing ratio of 5.1 times) 500 drlS.
2. Next to f, what is the stretching speed? I[ as OOsg/min
The experiment was conducted under the conditions shown in Table 2. The results are also listed in the same table, and the same experimental facts as in Table 1 were revealed from the wood table.

Claims (1)

[Claims] 1) Birefringence: 0.010 to 0.0550゛Polyester undrawn yarn is left at 2 oxs 0℃ for 20 hours or more, and then the maximum stretching ratio of the undrawn yarn is 60 in a heated atmosphere of 70℃ or less. 〜7s96, and then the drawn yarn (
7), 0. It is characterized by heat setting at 90 to 120°C under conditions of 990 times to substantially no stretching.
5 times to 1. (l 6., o times the uneven drawing yarn manufacturing method.