JPS5855251B2 - Tokushiyukakoshino Seizouhouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is based on the conventional hard twist-heat setting method or the false twist and knee hard twist method.
The present invention relates to a method for economically producing textured yarn for textured woven or knitted fabrics such as joints or organdy, which have been produced by heat-setting methods or the like.

For a long time, thin woven and knitted fabrics have been made using heavily twisted cotton or silk threads for the purpose of giving them a crisp feel, but heating the threads is an extremely inefficient process, which inevitably leads to high costs.

Recently, synthetic fibers have been applied to replace cotton threads and silk threads, and in particular, with the development of false twisting processing, methods such as false twisting and knee hard twisting, or pre-twisting and false twisting processing have made it possible to achieve this high twisting. Although it became possible to considerably reduce the degree of twisting and improve the efficiency of the process, it was still not possible to completely eliminate the need for real twisting.

The present inventors aim to solve these problems and efficiently produce knitted fabrics with a crisp feel, as well as develop new products with even better textures (as a result of repeated research,
In order to give a knitted fabric made of thermoplastic multifilament an appropriate crispness and good texture, the thermoplastic multifilament must have parts where each filament is fused to each other along the longitudinal direction of the fibers and parts that have been processed to be bulky. They have found that it is effective to exist alternately and continuously, and have arrived at the present invention.

In order to obtain such a yarn, the present invention has a birefringence of 5×10
``Using undrawn polyester multifilament yarn with a crystallinity of 4% or more and 16% or less, and a natural draw ratio of 1.2 or more and 2.8 or less,
When performing an out-of-the-way one-way stretch false twisting process on this material, the process is carried out at a much lower draw ratio than in the past, and at a heater temperature that is relatively high.

Conventionally, as a method for obtaining specially textured yarn with a crisp feel, thermoplastic synthetic fibers made of two or more different polymers are aligned or twisted, and then false twisted to create sections in the longitudinal direction of the multifilament. However, since these methods require doubling yarns, they are forced to be thicker than processed yarns made from single yarns. If you want to obtain a yarn with the same thickness as that made from single yarn, you will have to start from an extremely fine yarn, which inevitably increases the cost.

Furthermore, dyeability of such yarns poses a problem even in subsequent processing, and uneven coloring or a decrease in color fastness is likely to occur.

In the present invention, since only a single undrawn polyester yarn is used, the above-mentioned drawbacks do not occur.

Undrawn yarn has a birefringence index of 5X10-3 or more 70XI
O'' or less, crystallinity is 4% or more and 16% or less, and natural stretch ratio is 12 or more and 2.8 or less. The temperature of the heater (where Dn represents the natural stretching ratio of the undrawn yarn).

).

Birefringence in the present invention is a Nippon Kogaku POH3 polarizing microscope using a Bahine type compensator, an incandescent lamp as a light source, and a filter of X=466 m.
It was calculated using a μ green filter.

The degree of crystallinity is determined by measuring the density using a density gradient tube made from a mixture of carbon tetrachloride and n-hebutane, and converting the value using the formula %-x/du+(1-x)/damO. It's what I asked for.

Here, d represents the density, X represents the degree of crystallinity (%), du represents the density of the crystalline portion, and dam represents the density of the amorphous portion.

Further, the natural stretching ratio was calculated from the S-8 curve measured using an automatic recording type stretching tester under the conditions of a sample length of 20 crrL and a tensile speed of 20 crIL per minute.

An undrawn polyester yarn having physical properties such as a birefringence of 9 x 10-'', a crystallinity of 5.2%, and a natural draw ratio of 2.6 can be produced industrially, for example, by the following method.

That is, a polymer chip made of polyethylene terephthalate with an intrinsic viscosity of 0.65 is extruded from an extruder at 290°C, discharged through a spinneret, cooled by spraying cooling gas, and then an appropriate finishing agent is applied. 150
The desired undrawn yarn can be obtained by winding at a winding speed of 0 m/min.

Further, semi-drawn polyester yarn having a birefringence index of 51 x 10-'', a crystallinity of 9.7%, and a natural draw ratio of 1.5 can be industrially produced, for example, by the following method.

That is, polymer chips made of polyethylene terephthalate with an intrinsic viscosity of 0.65 were extruded from an extruder at 290°C, discharged through a spinneret, cooled by blowing cooling gas, and then an appropriate finishing agent was applied to the extruder at 3500 rr.
By winding at a winding speed of L/min, the desired semi-drawn yarn can be obtained.

In the drawn false twisting process according to the method of the present invention, the birefringence of the multifilament undrawn yarn, which is the raw yarn, is 5 x 10-3.
If the crystallinity is less than 4% and the natural draw ratio is greater than 2.8, the spinning speed is too low.
The orientation of the twisted yarn is so low that it cannot be used for practical purposes.

On the other hand, if the birefringence is greater than 70X10-3, the crystallinity is greater than 16%, and the natural draw ratio is less than 1.2, it is due to high-speed spinning at a spinning speed of 4500 m/mj+ or higher, and the yarn is too thin. is highly oriented and is unsuitable for the present invention, which attempts to create a partially stretched portion in an out-of-the-way one-way process.

Therefore, the birefringence, crystallinity, and natural draw ratio of the supplied yarn must be within the above ranges.

Undrawn yarn wound at a relatively low speed of about 1,500 m/min is more susceptible to structural and morphological changes than so-called semi-drawn yarn wound at a speed of about 2,500 m/min to 3,500,771 min. In the indolo set drawing false twisting method, the undrawn yarn tends to melt and break on the heater, and threading is time-consuming, and the resulting processed yarn is inferior to semi-drawn yarn in terms of level dyeing properties, number of fuzz, etc. It is normal to be inferior.

On the other hand, when these undrawn yarns and semi-drawn yarns are processed by the out-of-the-way set drawing false twisting method, the drawing ratio is applied to each yarn to form a drawn yarn, and then the false twisting process is performed. Therefore, melting and breakage of the single filament and generation of fuzz as in the case of the indolo set are prevented, and the level dyeing property is also good.

In this way, the out-of-the-way draw and false twist process is widely applicable to various types of undrawn yarns, and can also be used effectively for low spinning speed undrawn yarns, which tend to have poor operability due to high-temperature false twisting heaters. It has characteristics.

The present invention takes advantage of the wide adaptability of the out-of-the-way set drawing false twisting method to draw the undrawn yarn at a much lower ratio than previously thought. When producing a yarn with scattered orientation areas and subsequently processing it with a false twisting machine, the temperature of the false twisting heater is set in a range considerably higher than that adopted in normal stretching false twisting processing. This fuses the low-orientation portions of each filament along the length of the yarn, and provides bulk to the highly-orientation portions.

In addition, since fusion of the yarn occurs during heating, the fused portion and bulky portion coexist not only in the length direction but also in the cross-sectional direction of the yarn, resulting in a knitted fabric. In this case, it is possible to obtain a special bulky processed yarn that has a crisp feel and is firm at the same time.

To explain the present invention in more detail, in the method according to the present invention, as described above, the birefringence is 5×10” or more and 70×10−
3 or less, a crystallinity of 4% or more and 16% or less, and a natural draw ratio of 1.2 or more and 2.8 or less, polyethylene terephthalate undrawn yarn is subjected to an out-draw set drawing false twisting process, but generally polyethylene terephthalate undrawn yarn is When performing out-draw drawing and false twisting, the drawing ratio is higher than the natural drawing ratio of the undrawn yarn, that is, the spinning speed is 10.
Approximately 4 times, 2 times for polyester undrawn yarn of 0077Z/min
00077Z/min is about 2.5 times, 300
011 L/min is drawn at a draw ratio of about 1.9 times to give the same degree of orientation as ordinary drawn yarn, whereas in the method of the present invention, the above-mentioned ordinary out-draw set drawing false twisting is applied. In this method, the yarn is drawn at a draw ratio that is considerably lower than the draw ratio in the method, that is, at a draw ratio that is relative to the natural draw ratio Dn of the undrawn yarn, and the yarn is made to have portions with a low degree of orientation scattered along the longitudinal direction.

The portions with a low degree of orientation are more easily fused at a lower temperature and have lower thermal shrinkage stress than the portions with a higher degree of orientation.

In this way, yarns with uneven orientation are subjected to false twisting while continuously applying high heat.

In the case of polyethylene terrestrial filament yarn, the temperature of the false twisting heater is usually 180°C for one-way intrusion.
to 210°C, and in the outdoor one-way system, it is usually about 200°C to 220°C, but in the present invention, the heater temperature T is set according to the natural stretching ratio DnO value according to the following formula.
is changing.

In the draw false twisting process according to the method of the present invention, if the stretching ratio in the subsequent outdraw process is too low compared to the natural stretching ratio of the supplied raw yarn, the degree of orientation of the yarn in the false twisting heater area becomes too small, and the temperature This is a practical problem as it is sensitive to heat and easily causes fusion.

On the other hand, if the stretching ratio in the outdraw process is too high, the yarn becomes highly oriented and fails to exhibit the desired fusion bond.

Therefore, there is an appropriate stretching ratio with respect to the natural stretching ratio of the supplied yarn, and this is also related to the temperature of the heater.

As a result of analyzing a large number of experimental results, the present inventors found that there is an appropriate range in the shaded area in FIGS. 4 and 59.
・We derived the above equations 1) and (2).

However, in the draw false twisting process according to the method of the present invention, if the draw ratio is lower than the lower limit of formula (1) above, the semi-drawn yarn entering the false twist area from the drawing area becomes thermally unstable, and the false twist heater Even if the temperature T is within the preferred range of formula (2), a severe fusion state is exhibited, the strength of the yarn is greatly reduced, and the resulting processed yarn becomes coarse and hard.

Furthermore, if T exceeds the upper limit of formula (2) above, thread breakage occurs frequently when threading is carried out at the time of starting the machine, making it impossible to operate.

Furthermore, if the drawing ratio exceeds the upper limit of formula (1), the yarn becomes too thermally stable in the drawing region, and the resulting processed yarn becomes a relatively homogeneous bulky yarn, which is difficult to achieve in the present invention. The yarn does not have the crisp feel that is desired.

As explained above, according to the method of the present invention, a processed yarn with excellent crispness can be produced in one step from a single undrawn yarn or semi-drawn yarn using an out-of-the-way one-way drawing and false twisting machine. can.

Examples of the present invention will be described in detail below, but the present invention is not limited thereto in the least.

The birefringence [Δn], crystallinity (K), and cutting elongation [ξB] in the examples are the values measured by the method described above.

Example 1 After melting polyethylene terephthalate at 290°C, it was discharged at a rate of 70 g/min through a spinneret with a hole diameter of 0.4 mm and a number of holes of 32, and cooled with an air flow at 20°C.
It was wound up at a speed of Z/min.

The resulting undrawn yarn has a cutting strength of 1.3t? /d, cutting elongation 340%, natural stretching ratio 2.8, crystallinity 10.4%,
The birefringence was 9×10 −3 and the fineness was 460 denier.

The undrawn yarn was drawn at a draw ratio of 2.0 by an out-dro one-way drawing false twister equipped with a 5T-6 plate twister manufactured by Mitsubishi Heavy Industries, Ltd. and equipped with a drawing section.
05, stretching heater temperature 100°C, spindle rotation speed 27
500OR/u, number of false twists 2480T/M, false twisting heater temperature 220℃, overfeed rate +3%, stretching and false twisting was performed. Threading was easy and one skilled worker could spin 24 spindles in 16 minutes. I was able to complete it.

In addition, the operating conditions were good, and the number of threads cut per hour for 188 spindles was 0.2.

The strength of the obtained textured yarn was 2.5 f/d, the breaking elongation was 53%, and the elongation hardness was 3.7%, which is outside the scope of the present invention using the same undrawn yarn as shown in Table 1. It exhibited superior crispness compared to polyester processed yarn processed under these conditions.

*(This is a characteristic value defined by the present inventors as a measure of the crispness of processed yarn.

The processed yarn to be measured is approximately 30 cIrL long (when stretched) as a sample.
20cm (a) from the crimp line after 30 seconds. Tsugeru.

Next, apply a load of 1/20 f/d to the indicated denier and measure the length b) of the sample after 30 seconds.

From these measured values, the following formula is used to calculate the elongation hardness (%)
” is calculated.

The number of tests is 10 and the average value is taken.

It has been recognized that the fact that this value is large is correlated with the fact that the woven or knitted fabric made from the processed yarn exhibits a crisp feel.

) Example 2 After melting polyethylene terephthalate at 290°C, it was discharged at a rate of 431/min through a spinneret with a hole diameter of 0.4 mm and a number of holes of 32, cooled with an air flow at 21°C, and then spun at a rate of 3500 m/min.
It was wound at a speed of 1 minute.

The obtained semi-drawn yarn had a cutting strength of 2.5 y/ci, a cutting elongation of 122%, a natural draw ratio of 1.4, a crystallinity of 13.9%,
The birefringence was 52×10” and the fineness was 120 denier.

This semi-drawn yarn was processed using an out-draw set drawing false twisting machine equipped with a stretching section in a Mitsubishi Heavy Industries model LS-6 24-spindle false twisting tester, at a draw ratio of 1.04, a draw heater temperature of 110°C, and a spindle rotation speed. 32500OR/M.

False twist number 3350T/M, first heater temperature 230℃, first
When stretch false twisting was performed under the conditions of feed rate +3%, second heater temperature 220℃, *second feed rate +10%, there was no yarn breakage during thread hanging, and the number of yarn breaks calculated from 188 spindles per hour. was 0.25.

Also, as shown in Table 2, the strength of the processed yarn obtained was 2.8 f/
d. The elongation at break was 49%, the elongation hardness was 3.9%, and the yarn had an excellent crisp feel compared to the same undrawn yarn made under conditions outside the scope of the present invention.

Comparative Example 1 An undrawn yarn spun and wound under the same conditions as in Example 1 was subjected to a stretching ratio of 2.90, a stretching heater temperature of 100%, a spindle rotation speed of 27500 OR/M, and a false twist number of 2480 T/M1.
Stretching and false twisting was attempted as Test A2 at a false twisting heater temperature of 220° C. and an overfeed rate of +3%, but the textured yarn obtained was no different from ordinary bulky textured yarn.

Comparative Example 2 An undrawn yarn spun and wound under the same conditions as in Example 1 was subjected to a stretching ratio of 1.55, a stretching heater temperature of 100°C, a spindle rotation speed of 27500 OR/M, and a false twist number of 2480 T/M.
Stretching and false twisting was performed as Test &7 at a false twisting heater temperature of 185° C. and an overfeed rate of +3%.

Although threading was possible, the operating conditions were poor and 188 spindles were used.
The number of yarns cut per hour was 2.3, and the resulting processed yarn was untwisted over the entire length of the yarn in the longitudinal direction.
It was a coarse and hard yarn with no bulking effect.

[Brief explanation of the drawing]

FIG. 1 is a process diagram showing one example of an embodiment of the present invention. 1: undrawn yarn package, 2: undrawn yarn, 3: feed roller, 4: drawing heater, 5: draw roller, 6: false twist heater, 7: false twist spindle, 8: second feed roller, 9: second Heater, 10: Third feed roller, 11
: Take-up roller, 12: DTY package. FIG. 2 shows the structure of a thread according to the prior art. FIG. 3 shows the structure of processed yarn produced by the method of the invention using the apparatus shown in FIG. FIG. 4 is a graph showing the range of the natural stretch ratio and the preferred stretch ratio of the supply system in the present invention. FIG. 5 is a graph showing the range of natural stretching ratio and suitable heater temperature of the supply system in the present invention.

Claims (1)

[Claims] 1. Made of polyethylene terephthalate, has a birefringence of 5 x 10-3 or more and 70 x 10'' or less, a crystallinity of 4% or more and 16% or less, and a natural stretching ratio of 1.2 or more and 2 When performing an out-of-the-way crimping process using a false-twisting heater on a multifilament undrawn yarn having a diameter of . Manufacture of specially processed yarn, characterized in that the temperature T of the multifilament is set so as to satisfy the following formula (2) and false twisting is performed, and the fused parts and bulky parts are arranged alternately along the longitudinal direction of the multifilament. Method: 0.425XDn+0.49≦D≦0.750XDn+
0.17...(1) 225-(12,5XDn)≦T≦260-(12,5
X Dn )...(2) (However, Dn represents the natural draw ratio of the undrawn yarn.)