JP7259200B2 - polyester false twisted yarn - Google Patents

Description

TECHNICAL FIELD The present invention relates to a polyester false-twisted yarn with a natural texture that can exhibit a soft feel and contact feeling, a finely dispersed natural heathered feel, and moderate softness when woven or knitted.

Synthetic fibers are widely used in the field of general clothing because of their various excellent properties including mechanical properties. In particular, for knitted fabrics using polyester, various polyester fluff yarns, loop yarns, and spun-like yarns have been proposed as materials that express the fluffiness and texture of natural fibers when made into fabrics. These are textured yarns in which fluff and loops are present in the yarn by cutting or loosening single filaments of multifilaments by air treatment applied during drawing or false twisting. In particular, by controlling the number of fluff/loops and the cross-sectional shape of the single filament, a polyester fluff yarn has been proposed that has a natural, spun-like touch and feel (Patent Document 1). However, in this proposal, due to the uniformity of dyeing that is peculiar to synthetic fibers, when it is made into a fabric, the color tone is poor and the fabric looks artificial.

On the other hand, various proposals have been made for polyester thick and thin drawn yarns and thick and thin false-twisted textured yarns, which are intended to improve the appearance of the yarn. In particular, polyester multifilament partially oriented undrawn yarn is processed at a draw ratio equal to or lower than the constant stress region to develop a partially undrawn thick portion in the single filament, or a relaxation heat treatment is applied to the partially oriented undrawn yarn. A proposal has been made for a polyester yarn that has a gradation change in the longitudinal direction of the yarn due to the difference in molecular orientation and the difference in dye adsorption by making the single filament develop a partial thick part (Patent Document 2, 3).

JP-A-8-260278 JP 2017-106141 A JP-A-7-90739

However, in any of the patent documents, the fiber diameter difference and molecular orientation difference in the thick part are large, and the pitch of the single filament is also large, so when it is made into a fabric, the color difference contrast is large, and the heathered fabric is rough. Therefore, there is a problem that it is far from the natural heathered feeling of natural materials.

To provide a natural material-like false twisted polyester yarn capable of exhibiting a soft touch and touch feeling, finely dispersed natural heathered feeling, and appropriate softness when woven or knitted.

In order to solve the above problems, the number of fluffs to be developed in the polyester false twisted yarn, the single filament fineness, the longitudinal fineness unevenness of the multifilament, and the stretch recovery rate of the multifilament were extensively studied.

As a result, the present invention is a polyester multifilament false-twisted yarn, has fluff that is shredded in the longitudinal direction of the yarn, and has the following (1) to (4) to solve the problems.
(1) The frequency of fluff is 100 to 400 /25m.
(2) The average single filament fineness of the multifilament is 0.5 to 1.5 dtex.
(3) Longitudinal fineness unevenness of multifilament is 1.3 to 2.0%.
However, the unevenness of the longitudinal fineness of multifilament is the U% normal value measured using a USTER TESTER under the conditions of an unwinding speed of 25 m/min, an S twist of 4000 T/m in the twisting direction, and a measurement time of 3 minutes. That is.
(4) The multifilament stretch recovery rate CR is 15% or more.

According to a preferred embodiment of the polyester false twisted yarn of the present invention, the average length of the fluff is 1.0 mm or more.

According to a preferred embodiment of the polyester false twist yarn of the present invention, it contains 0.2 to 3.0% of titanium oxide.

According to a preferred embodiment of the polyester false twist yarn of the present invention, any 50% of all single filaments constituting the multifilament have a cross-sectional flatness of 1.5 to 2.5.

According to the present invention, it is possible to provide a natural material-like false twisted polyester yarn capable of exhibiting a soft texture and touch feeling, a finely dispersed natural heathered feeling, and appropriate softness when woven or knitted.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic side view for illustrating the polyester false twisted yarn of the present invention; BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram for illustrating the cross section of a single filament of the polyester false twist yarn of the present invention; BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram for explaining the processing steps of the polyester false twisted yarn of the present invention. 1 is a schematic diagram of a tension elongation curve for explaining the natural draw ratio of a partially oriented undrawn yarn used in the polyester false twisted yarn of the present invention. FIG.

Next, the polyester false twisted yarn of the present invention will be described in detail.

The polyester false-twisted yarn of the present invention is a multifilament made of a single polyester component, and has fluff (FIG. 1-2) cut in the longitudinal direction of the yarn.

The number of fluffs present in the longitudinal direction of the multifilament yarn of the polyester false twist yarn of the present invention is 100 to 500/25 m, preferably 200 to 400/25 m. If the number of fluffs is less than 100 per 25 m, the fluff ends do not provide a soft touch and touch feeling when touched. If the number of fluffs exceeds 500 per 25 m, the touch becomes rough and the fluffs cling to each other, resulting in a poor contact feeling. Moreover, it is not preferable from the viewpoint of fiber strength, spinnability, and fabric quality.

The average single filament fineness of the multifilaments of the polyester false twist yarn of the present invention is 0.5 to 1.5 dtex, preferably 0.6 to 1.3 dtex. If the average single filament fineness is less than 0.5 dtex, the single filament fineness is thin, so the difference in fiber diameter between thick and thin single filaments and the length of the thick portion of the single filament are not sufficient, and the woven or knitted fabric is finely dispersed and natural. It does not give a heathered feeling. Furthermore, the fabric does not have stiffness, and the woven or knitted fabric does not have appropriate softness, and soft touch and touch feeling due to fluff cannot be obtained. When the single filament fineness exceeds 1.5 dtex, the single filament fineness is large, so that the difference in fiber diameter between thick and thin single filaments is large, and the thick portion of the single filament becomes long, resulting in a rough heathered fabric. Furthermore, the fabric is hard and a woven or knitted fabric with appropriate softness cannot be obtained.

The longitudinal fineness unevenness of the entire multifilament in the polyester false twist yarn of the present invention is 1.3 to 2.0%, preferably 1.4 to 1.9%. If the longitudinal fineness unevenness is less than 1.3%, the region in which relatively many single filament thick parts are aggregated is insufficient in the multifilament, and the woven or knitted fabric does not have a finely dispersed natural heathered feel. On the other hand, if it exceeds 2.0%, the area in which the thick portions of the single filaments are relatively aggregated in the multifilament becomes excessive, and the woven or knitted fabric becomes a rough heathered fabric.

The stretch recovery rate CR of the multifilament in the polyester false twist yarn of the present invention is 15% or more, preferably 20% or more. When the stretch recovery rate CR of the multifilament is less than 15%, there is no crimping property, and the contact area between the skin and the fiber increases, giving a slimy feel, and soft touch and contact feeling cannot be obtained. Furthermore, the flexural rigidity of the fiber is increased, making the fabric hard and making it impossible to obtain a woven or knitted fabric with appropriate softness.

According to a preferred embodiment of the polyester false twisted yarn of the present invention, the average length of fluff is 1.0 mm or more. As a result, the fluff improves the soft touch and touch feeling, and the range of use, especially for innerwear, is greatly expanded. More preferably, it is 1.5 mm or more.

According to a preferred embodiment of the polyester false twist yarn of the present invention, it contains 0.2 to 3.0% of titanium oxide. As a result, the unevenness caused by the titanium oxide particles on the side surface of the single filament reduces friction and further improves the soft touch and contact feeling. More preferably 0.3 to 2.5%.

According to a preferred embodiment of the polyester false twisted yarn of the present invention, the cross-sectional flatness of the false twisted yarn is 1.5 to 2.5. As a result, the bending rigidity of the fibers can be suppressed, and a woven or knitted fabric having remarkably good softness, such as good drapeability, is obtained while maintaining the stiffness of the fabric. It is more preferably 1.7 to 2.2. The cross-sectional flatness is calculated as major axis a/minor axis b (Fig. 2) in the cross section of the single filament. In an elliptical cross section (FIGS. 2-3), the major axis a is the largest diameter of the cross section and the minor axis b is the length of the largest diameter while remaining perpendicular to a. In the cross section having one recess (FIG. 2-4), the major axis a is the maximum diameter of the cross section, the minor axis b is perpendicular to a, and the length b1 at which the diameter is the maximum, It is the average value of the diameter b2 passing through the apex of the recess while maintaining a right angle with respect to a. Furthermore, in the cross section having two recesses (FIG. 2-5), the major axis a is the maximum diameter of the cross section, the minor axis b is perpendicular to a, and the length b1 at which the diameter is the maximum, It is the average value of the diameters b2 and b3 passing through the apex of the recess while maintaining a right angle with respect to a. Therefore, the cross-sectional flatness is similarly calculated as bn for a cross-section having n concave portions.

Next, a method for producing the polyester false twisted yarn of the present invention will be described. The raw material polymer used in the present invention is preferably polyester, and polyethylene terephthalate can be preferably used from the viewpoint of mechanical properties and fabric texture. A partially oriented undrawn yarn (multifilament) can be obtained by melt-spinning these by a conventional method. That is, the partially oriented undrawn yarn is obtained by melting a raw material polymer at a temperature of preferably 275° C. to 300° C., discharging it from a spinneret to form a yarn, and cooling the yarn by blowing cooling air. After convergence, oil and entanglement can be applied to form a wound package. Partially oriented undrawn yarn is generally a package spun and wound at a spinning speed of about 2000 m/min to 4000 m/min. It is not a mixed state, but a state in which the molecular chains are uniformly oriented in the longitudinal direction of the yarn. The multifilament is composed of a large number of single filaments, and the total fineness and the number of single filaments can be arbitrarily adopted. If the single filament fineness CV% of the partially oriented undrawn yarn is set to 0.1 or less, the single filament fineness of some of the single filaments will not be thin or the fineness of some single filaments will be thick, and the woven or knitted fabric will have a finely dispersed natural It can be done with a heathered feeling. Further, a second component such as titanium oxide or a third component may be added within the scope of the present invention, and the second and third polymers may be copolymerized at the polymer molecular chain level.

Next, the polyester false twisted yarn of the present invention can be obtained by drawing and false twisting the partially oriented undrawn yarn. FIG. 3 is a schematic diagram for explaining the processing steps of the polyester false twisted yarn of the present invention. The processing of the polyester false twisted yarn of the present invention is performed by first drawing the partially oriented undrawn yarn using a drawing pin (Fig. 3-8). remains in the thick portion of the single filament, and appears randomly along the length of all the filaments that make up the multifilament. Thereafter, by subjecting the yarn to false twisting at the same time as the second drawing, the thick portion of the single filament is broken by twisting and untwisting to generate fluff, and a false twisted yarn with a natural texture can be obtained. .

In the first drawing, it is appropriate to draw at 90% or less of the constant stress region (Fig. 4-19) of the partially oriented undrawn yarn, the number of thick portions of the remaining single filaments is stabilized, and sufficient fluff is obtained. number can be expressed. Furthermore, the length of the thick part of the single filament becomes appropriate by setting the position of the drawing pin so that the yarn length between the drawing pin and 1 feed roller (hereinafter referred to as 1FR) (Fig. 3-9) is in the range of 15 to 150 mm. , a knitted or woven fabric having a finely dispersed, natural heathered feel as described above can be obtained. In addition, a thick and thin molecular orientation difference can be secured, and a heathered feeling is expressed. By applying simultaneous false twisting in the second drawing, the yarn is drawn and twisted while being heated, and then untwisted to generate fluff and become a natural material-like false twisted yarn with a bulky texture.

As an example of a specific manufacturing method, the temperature of the drawing pin is preferably 55° C. to 85° C. from the viewpoint of the number of fluffs generated. The temperature of the first heater during false twisting is preferably in the range of 150° C. to 230° C. from the viewpoint of the number of fluffs generated and workability. In false twisting, the yarn is twisted by bringing it into contact with a rotating friction disk (Fig. 3-12). When the twisting tension T1 directly above the friction disk, the untwisting tension T2 at the exit of the friction disk, and the working tension ratio are T2/T1, the working tension ratio is preferably 1.5 or more. Generally, in false twisting with a friction disk, processing at a processing tension ratio in the vicinity of 0.5 to 1.5 is a common method, and the method for producing a polyester false twist yarn of the present invention positively increases the processing tension ratio. A method of false twisting at a higher height is preferable from the viewpoint of the number of fluffs generated. The draw ratio in the second draw depends on the degree of orientation of the partially oriented undrawn yarn, the number of fluffs generated, and the target toughness of the false twisted yarn, and any value can be adopted. From the viewpoint of texture change, the second heater (Fig. 3-14 ), a method of heating the yarn can also be arbitrarily adopted. From the viewpoint of the strength and high-order passability of the false twisted yarn for weaving and knitting, a method of imparting entanglement (Fig. 3-16) to the yarn with compressed air can be employed, and the degree of entanglement is preferably in the range of 100 to 250.

Next, the polyester false twist yarn of the present invention will be described in detail with reference to examples. Each measured value and evaluation used in Examples and Comparative Examples were determined by the following measurement methods.

<Number of fluff>
The false-twisted yarn of the present invention is run at an unwinding speed of 400 m/min and a sample length of 400 m (measurement time: 1 minute). The number of fluffs detected was measured at a distance of 1.5 mm, and the number of fluffs per 25 m was calculated according to the following formula.
Number of fluff=number of detected fluff/400×25.

<Average single filament fineness of multifilament>
The false-twisted yarn of the present invention is wound 100 times with an unwinding tension of 1/11.1 g/dtex using a measuring machine with a frame circumference of 1.0 m, the weight is measured using a balance, and the weight obtained by multiplying by 100 is calculated. It was taken as the total fineness of the multifilament. The obtained total fineness was divided by the number of single filaments constituting the multifilament to calculate the average single filament fineness of the multifilaments. The number of constituent monofilaments is confirmed by counting the number of monofilaments of the partially oriented undrawn yarn.

<Longitudinal fineness unevenness of multifilament>
Using USTER TESTER UT-4 manufactured by ZELLWEGER USTER, the false twisted yarn of the present invention was measured under the conditions of an unwinding speed of 25 m / min, an S twist of 4000 T / m in the twisting direction, and a measurement time of 3 minutes. The output result of was taken as the longitudinal fineness unevenness of the multifilament.

<Stretching recovery rate CR>
After winding the false twisted yarn 10 times with a measuring machine having a circumference of 1.0 m and removing the skein, the skein was subjected to an initial weight of fineness x 0.002 x number of windings x 2/1.111 g, and 90 ℃×20 minutes, and left for 12 hours or more after dehydration. The skein after standing is subjected to a measurement load of initial load and fineness x 0.1 x number of windings x 2/1.111 g, suspended in water and left for 2 minutes. Measure the length of the left skein and call it L. After removing the measurement load and applying only the initial load, leave the sample for 3 minutes. The expansion/contraction recovery rate CR was determined by the following formula.
Stretch recovery rate CR (%)={(L-L1)/L}×100.

<Percentage of fluff length 1.0 mm or more>
The false twisted yarn of the present invention is sampled, enlarged and inspected with a microscope VHX-5000 manufactured by Keyence Corporation, and the length of fluff is measured. Measurements were taken from the fluff tip of the cut single filament to the mixed filament portion with the multifilament on the image. The curved fluff on the image was measured by comparing 10 or more points with the fluff on the image in the multi-point distance measurement mode. An average value of 20 fluffs/sample was calculated.

<Titanium oxide content>
A sample of 5 g of the false twist yarn of the present invention was placed in a magnetic crucible and incinerated at 1000° C. using an electric furnace.

<Cross-Sectional Flatness of False Twisted Yarn>
An embedding agent consisting of paraffin, stearic acid, and ethyl cellulose was dissolved, and after the false twisted yarn of the present invention was introduced, it was allowed to stand at room temperature to solidify. I inspected it. Arbitrary 50% of all single filaments constituting the multifilament were selected, and the length of the major axis to the minor axis was calculated as the cross-sectional flatness.
Cross-sectional flatness = major axis a/minor axis b
However, in the elliptical cross section (FIGS. 2-3), the major axis a is the maximum diameter of the cross section, and the minor axis b is the length of the maximum diameter while maintaining a right angle to a.

In the cross section having one recess (FIG. 2-4), the major axis a is the maximum diameter of the cross section, the minor axis b is perpendicular to a, and the length b1 at which the diameter is the maximum, It is the average value of the diameter b2 passing through the apex of the recess while maintaining a right angle with respect to a.

Furthermore, in the cross section having two recesses (FIG. 2-5), the major axis a is the maximum diameter of the cross section, the minor axis b is perpendicular to a, and the length b1 at which the diameter is the maximum, It is the average value of the diameters b2 and b3 passing through the apex of the recess while maintaining a right angle with respect to a.

Therefore, the cross-sectional flatness is similarly calculated as bn for a cross-section having n concave portions.

<Soft touch/contact feeling, natural heathered feeling, softness of fabric>
A woven fabric was produced using the false twisted yarn of the present invention, and a sensory evaluation was carried out with respect to the soft feel and contact feeling, the natural heathered feeling, and the softness of the fabric. As a blank, a woven fabric made from the false twisted yarn of Comparative Example 10 was used, and 10 panelists were asked to rate it on a scale of 1 to 10, and it was evaluated in the following four stages.
○○: The average value of 10 panelists is 9 points or more ○: The average value of 10 panelists is 7 points or more and less than 9 points △: The average value of 10 panelists is 5 points or more and less than 7 points ×: 10 people of panelists with an average score of less than 5 points.

(Example 1)
Using a spinneret with 72 holes and a round hole shape, melt-spun at a spinning speed of 3100 m/min to obtain a 140 dtex-72 filament with a titanium oxide content of 0.3 wt% and a single filament CV% of 0.04 polyethylene terephthalate partially oriented. An undrawn yarn was obtained. In the false twisting process, a drawing pin with a surface temperature of 80°C is placed at a distance of 55 mm from 1FR, a contact heating element (first heater) of 1500 mm, a contact cooling device of 25°C, and two polyurethane friction discs. Using a false twisting device with the above configuration, the first heater temperature is 226° C., the first draw ratio is 1.229, the second draw ratio is 1.347, and the speed ratio of the friction disk surface to the yarn running speed is 1. Draw false twisting was carried out under the condition of 0.49 to obtain a polyester false twisted yarn having a fineness of 87 dtex. The number of fluffs in the obtained false-twisted yarn was 388 pieces/25 m, the average single filament fineness of the multifilament was 1.2 dtex, the longitudinal fineness unevenness of the multifilament was 1.5%, and the stretch recovery rate CR of the multifilament was 29%. Met. The fluff had an average length of 1.7 mm and a cross-sectional flatness of 1.7. The woven fabrics produced using these fabrics had a good soft feel and good contact feeling, and had a natural heathered feel and moderate softness. Table 1 shows the results.

(Example 2)
Draw false twisting was carried out in the same manner as in Example 1 except that the speed ratio of the friction disk surface to the running speed of the yarn during false twisting was set to 1.39. 498 pieces/25 m, the average single filament fineness of the multifilament was 1.2 dtex, the longitudinal fineness unevenness of the multifilament was 1.6%, and the stretch recovery rate CR of the multifilament was 26%. The fluff had an average length of 2.0 mm and a cross-sectional flatness of 1.6. The woven fabrics produced using these materials had a soft texture and touch feeling, and had a natural heathered feel and moderate softness. Table 1 shows the results.

(Example 3)
Draw false twisting was carried out in the same manner as in Example 1 except that the second draw ratio during false twisting was set to 1.266. The average single filament fineness of the filaments was 1.2 dtex, the longitudinal fineness unevenness of the multifilament was 1.5%, and the stretch recovery rate CR of the multifilament was 33%. The fluff had an average length of 1.5 mm and a cross-sectional flatness of 1.7. The woven fabrics produced using these materials had a soft texture and touch feeling, and had a natural heathered feel and moderate softness. Table 1 shows the results.

(Example 4)
False twisted yarn obtained as a result of draw false twisting in the same manner as in Example 1 except that the amount of polymer discharged during spinning was changed and a polyethylene terephthalate partially oriented undrawn yarn of single filament CV% 0.02 was used. The number of fluffs was 220 pieces/25 m, the average single filament fineness of the multifilament was 1.4 dtex, the longitudinal fineness unevenness of the multifilament was 1.7%, and the stretch recovery rate CR of the multifilament was 29%. The fluff had an average length of 1.7 mm and a cross-sectional flatness of 1.7. The woven fabrics produced using these fabrics had a good soft feel and good contact feeling, and had a natural heathered feel and moderate softness. Table 1 shows the results.

(Example 5)
Result of drawing false twisting in the same manner as in Example 1 except that the amount of polymer discharged during spinning and the spinneret of 96 holes were changed, and a polyethylene terephthalate partially oriented undrawn yarn with a single filament CV% of 0.08 was used. , The number of fluffs in the obtained false twisted yarn was 460/25 m, the average single filament fineness of the multifilament was 0.6 dtex, the longitudinal fineness unevenness of the multifilament was 1.8%, and the multifilament stretch recovery rate CR was 34. %Met. The fluff had an average length of 2.3 mm and a cross-sectional flatness of 1.6. The woven fabrics produced using these materials had a soft texture and touch feeling, and had a natural heathered feel and moderate softness. Table 1 shows the results.

(Example 6)
As a result of drawing false twisting in the same manner as in Example 1 except that the drawing pin position during false twisting was changed to a distance of 150 mm from 1FR, the number of fluffs of the obtained false twisted yarn was 353/25 m. The average single filament fineness of the multifilament was 1.2 dtex, the longitudinal fineness unevenness of the multifilament was 1.9%, and the stretch recovery rate CR of the multifilament was 28%. The fluff had an average length of 2.2 mm and a cross-sectional flatness of 1.7. The woven fabrics produced using these fabrics had a good soft feel and good contact feeling, and had a natural heathered feel and moderate softness. Table 1 shows the results.

(Example 7)
As a result of drawing false twisting in the same manner as in Example 1 except that the drawing pin position during false twisting was changed to a distance of 20 mm from 1FR, the number of fluffs in the obtained false twisted yarn was 330/25 m. The average single filament fineness of the multifilament was 1.2 dtex, the longitudinal fineness unevenness of the multifilament was 1.3%, and the stretch recovery rate CR of the multifilament was 27%. The fluff had an average length of 1.2 mm and a cross-sectional flatness of 1.6. The woven fabrics produced using these fabrics had a good soft touch and touch feeling, a natural heathered feeling, and moderate softness. Table 1 shows the results.

(Example 8)
Draw false twisting was carried out in the same manner as in Example 1 except that the speed ratio of the friction disk surface to the running speed of the yarn during false twisting was 1.33, and the temperature of the first heater was 195°C. The number of fluffs of the false twisted yarn was 401/25m, the average single filament fineness of the multifilament was 1.2dtex, the longitudinal fineness unevenness of the multifilament was 1.5%, and the stretch recovery rate CR of the multifilament was 16%. rice field. The fluff had an average length of 1.9 mm and a cross-sectional flatness of 1.5. The woven fabrics produced using these materials had a soft texture and touch feeling, and had a natural heathered feel and moderate softness. Table 1 shows the results.

(Example 9)
Draw false twisting was carried out in the same manner as in Example 1 except that the distance between the drawing pin during false twisting and 1FR was set to 20 mm, and the temperature of the first heater was set to 236°C. The number was 300 pieces/25 m, the average single filament fineness of the multifilament was 1.2 dtex, the longitudinal fineness unevenness of the multifilament was 1.5%, and the stretch recovery rate CR of the multifilament was 30%. The fluff had an average length of 1.0 mm and a cross-sectional flatness of 1.7. The woven fabrics produced using these materials had a soft texture and touch feeling, and had a natural heathered feel and moderate softness. Table 1 shows the results.

(Example 10)
Draw false twisting was performed in the same manner as in Example 1, except that the amount of titanium oxide contained in the polymer during spinning was changed to 3.0 wt%, and a polyethylene terephthalate partially oriented undrawn yarn with a single filament CV% of 0.09 was used. As a result, the number of fluffs in the false twisted yarn obtained was 135 / 25 m, the average single filament fineness of the multifilament was 1.2 dtex, the longitudinal fineness unevenness of the multifilament was 1.5%, and the stretch recovery rate of the multifilament was CR was 28%. The fluff had an average length of 2.0 mm and a cross-sectional flatness of 1.6. The woven fabrics produced using these materials had a soft texture and touch feeling, and had a natural heathered feel and moderate softness. Table 1 shows the results.

(Example 11)
Draw false twisting was carried out in the same manner as in Example 1 except that the amount of titanium oxide contained in the polymer during spinning was changed to 0.2 wt%. , the average single filament fineness of the multifilament was 1.2 dtex, the longitudinal fineness unevenness of the multifilament was 1.6%, and the stretch recovery rate CR of the multifilament was 31%. The fluff had an average length of 2.2 mm and a cross-sectional flatness of 1.6. The woven fabrics produced using these materials had a soft texture and touch feeling, and had a natural heathered feel and moderate softness. Table 1 shows the results.

(Example 12)
Draw false twisting was carried out in the same manner as in Example 1 except that the hole shape of the spinneret at the time of spinning was changed to a flat shape, and a polyethylene terephthalate partially oriented undrawn yarn of single filament CV% 0.09 was obtained. The number of fluffs in the obtained false twisted yarn was 362 pieces/25 m, the average single filament fineness of the multifilament was 1.2 dtex, the longitudinal fineness unevenness of the multifilament was 1.7%, and the stretch recovery rate CR of the multifilament was 18%. Met. The fluff had an average length of 2.1 mm and a cross-sectional flatness of 2.4. The woven fabrics produced using these fabrics had a good soft touch and touch feeling, a natural heathered feeling, and moderate softness. Table 1 shows the results.

(Comparative example 1)
Draw false twisting was carried out in the same manner as in Example 1 except that the speed ratio of the friction disk surface to the running speed of the yarn during false twisting was set to 1.33. 550 pieces/25 m, the average single filament fineness of the multifilament was 1.2 dtex, the longitudinal fineness unevenness of the multifilament was 1.8%, and the stretch recovery rate CR of the multifilament was 20%. The fluff had an average length of 2.2 mm and a cross-sectional flatness of 1.6. Textiles made from these fabrics lacked a soft feel and touch feeling. Table 2 shows the results.

(Comparative example 2)
Draw false twisting was carried out in the same manner as in Example 1 except that the second draw ratio during false twisting was set to 1.210. The average single filament fineness of the filaments was 1.2 dtex, the longitudinal fineness unevenness of the multifilament was 1.4%, and the stretch recovery rate CR of the multifilament was 33%. The fluff had an average length of 1.4 mm and a cross-sectional flatness of 1.6. The woven fabrics produced using these materials did not have a soft feel or touch feeling. Table 2 shows the results.

(Comparative Example 3)
False twisted yarn obtained as a result of drawing false twisting in the same manner as in Example 1 except that the amount of polymer discharged during spinning was changed and a polyethylene terephthalate partially oriented undrawn yarn of single filament CV% 0.02 was used. The number of fluffs was 151 pieces/25 m, the average single filament fineness of the multifilament was 1.6 dtex, the longitudinal fineness unevenness of the multifilament was 1.7%, and the stretch recovery rate CR of the multifilament was 29%. The fluff had an average length of 1.7 mm and a cross-sectional flatness of 1.7. The woven fabrics produced using these materials did not have a heathered feel and lacked appropriate softness. Table 2 shows the results.

(Comparative Example 4)
Result of drawing false twisting in the same manner as in Example 1 except that the amount of polymer discharged during spinning and the spinneret of 96 holes were changed, and a polyethylene terephthalate partially oriented undrawn yarn with a single filament CV% of 0.07 was used. , The number of fluffs of the obtained false twisted yarn was 451/25 m, the average single filament fineness of the multifilament was 0.4 dtex, the longitudinal fineness unevenness of the multifilament was 1.8%, and the multifilament stretch recovery rate CR was 35. %Met. The fluff had an average length of 2.8 mm and a cross-sectional flatness of 1.5. Textiles produced using these materials lacked soft touch and touch feeling, and also lacked heathered feel and moderate softness. Table 2 shows the results.

(Comparative Example 5)
As a result of drawing false twisting in the same manner as in Example 1 except that the drawing pin position during false twisting was changed to a distance of 180 mm from 1FR, the number of fluffs in the obtained false twisted yarn was 392/25 m. The average single filament fineness of the multifilament was 1.2 dtex, the longitudinal fineness unevenness of the multifilament was 2.2%, and the stretch recovery rate CR of the multifilament was 29%. The fluff had an average length of 2.6 mm and a cross-sectional flatness of 1.7. The woven fabrics produced using these lacked heathered feeling. Table 2 shows the results.

(Comparative Example 6)
As a result of drawing false twisting in the same manner as in Example 1 except that the drawing pin position during false twisting was changed to a distance of 10 mm from 1FR, the number of fluffs in the obtained false twisted yarn was 136/25 m. The average single filament fineness of the multifilament was 1.2 dtex, the longitudinal fineness unevenness of the multifilament was 1.2%, and the stretch recovery rate CR of the multifilament was 30%. The fluff had an average length of 1.1 mm and a cross-sectional flatness of 1.6. Fabrics produced using these materials did not have a heathered appearance. Table 2 shows the results.

(Comparative Example 7)
Draw false twisting was carried out in the same manner as in Example 1 except that the speed ratio of the friction disk surface to the running speed of the yarn during false twisting was 1.33, and the temperature of the first heater was 180°C. The number of fluffs of the false twisted yarn was 366/25m, the average single filament fineness of the multifilament was 1.2dtex, the longitudinal fineness unevenness of the multifilament was 1.5%, and the stretch recovery rate CR of the multifilament was 14%. rice field. The fluff had an average length of 2.3 mm and a cross-sectional flatness of 1.4. Textiles produced using these materials lacked soft texture and touch feeling, and also lacked appropriate softness. Table 2 shows the results.

(Comparative Example 8)
Drawing was carried out in the same manner as in Example 1, except that the amount of polymer discharged during spinning was changed to a spinneret with two types of discharge hole diameters in the 144 holes, and a polyethylene terephthalate partially oriented undrawn yarn with a single filament CV% of 0.3 was used. As a result of the false twisting process, the number of fluffs in the obtained false twisted yarn was 600/25 m, the average single filament fineness of the multifilament was 0.6 dtex, the longitudinal fineness unevenness of the multifilament was 1.2%, and the multifilament The stretch recovery rate CR was 35%. The fluff had an average length of 2.5 mm and a cross-sectional flatness of 1.7. The woven fabrics produced using these lacked heathered feeling. Table 2 shows the results.

(Comparative Example 9)
Drawing was carried out in the same manner as in Example 1, except that the amount of polymer discharged during spinning was changed to a spinneret with two types of discharge hole diameters in the 48 holes, and a polyethylene terephthalate partially oriented undrawn yarn with a single filament CV% of 0.2 was used. As a result of the false twisting process, the number of fluffs in the obtained false twisted yarn was 130/25 m, the average single filament fineness of the multifilament was 1.8 dtex, the longitudinal fineness unevenness of the multifilament was 1.8%, and the multifilament The stretch recovery rate CR was 29%. The fluff had an average length of 2.5 mm and a cross-sectional flatness of 1.5. Textiles produced using these materials lacked soft touch and touch feeling, and also lacked heathered feel and moderate softness. Table 2 shows the results.

(Comparative Example 10)
Result of draw false twisting in the same manner as in Example 1 except that the amount of polymer discharged during spinning and the spinneret with 48 holes were changed, and a polyethylene terephthalate partially oriented undrawn yarn with a single filament CV% of 0.02 was used. The number of fluffs in the obtained false twisted yarn was 103/25 m, the average single filament fineness of the multifilament was 1.8 dtex, the longitudinal fineness unevenness of the multifilament was 1.5%, and the stretch recovery rate CR of the multifilament was 28. %Met. The fluff had an average length of 1.8 mm and a cross-sectional flatness of 1.5. Textiles produced using these materials lacked soft touch and touch feeling, and also lacked heathered feel and moderate softness. Table 2 shows the results.

1: Multifilament false twist yarn 2: Fluff 3: Elliptical cross section 4: Cross section with one recess 5: Cross section with two recesses 6: Partially oriented undrawn yarn 7: 0 feed roller (0FR)
8: drawing pin 9: 1 feed roller (1FR)
10: First heater 11: Cooling plate 12: Friction disc 13: 2 feed rollers (2FR)
14: Second heater 15: 3 feed rollers (3FR)
16: Entanglement nozzle 17: False twist yarn 18: Tension elongation curve of partially oriented undrawn yarn 19: Constant stress region

Claims (5)

A polyester false-twisted yarn which is a multifilament composed of a single polyester component, has fluff in which the single filament is cut in the yarn longitudinal direction, and satisfies the following (1) to (4).
(1) The frequency of fluff is 100 to 400 /25m.
(2) The average single filament fineness of the multifilament is 0.5 to 1.5 dtex.
(3) Longitudinal fineness unevenness of multifilament is 1.3 to 2.0%.
However, the unevenness of the longitudinal fineness of multifilament is the U% normal value measured using a USTER TESTER under the conditions of an unwinding speed of 25 m/min, an S twist of 4000 T/m in the twisting direction, and a measurement time of 3 minutes. That is.
(4) The multifilament stretch recovery rate CR is 15% or more. 2. The polyester false-twisted yarn according to claim 1, wherein said fluff has an average length of 1.0 mm or more. The polyester false twisted yarn according to claim 1 or 2, containing 0.2 to 3.0% of titanium oxide. The polyester false-twisted yarn according to any one of claims 1 to 3, wherein arbitrary 50% of all single filaments constituting the multifilament have a cross-sectional flatness of 1.5 to 2.5. A knitted fabric in which the polyester false twisted yarn according to any one of claims 1 to 4 is arranged in a part of the structure.

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