JP7698946B2 - False twist textured yarn - Google Patents

Description

The present invention relates to a polyester filament false twist textured yarn having untwisted and untwisted portions in the longitudinal direction of the yarn.

Conventionally, as a processing method for imparting a linen-like special texture using polyester multifilaments, a method has been known in which the polyester multifilaments are false-twisted in a fusion high temperature range to partially fuse the single fibers to each other while simultaneously producing untwisted portions.
In other words, such textured yarns have a structure in which the multifilaments heated during false twist processing are partially fused, and untwisted sections that are fused and fixed in the same direction as the twist direction and untwisted sections that are untwisted in the opposite direction to the twist direction are alternated in the longitudinal direction of the yarn.

Patent Document 1 proposes a fusion-bonded draw-twisted yarn that can produce a fabric with a texture similar to that of real twist yarn and a faint ikat pattern by allowing the number and length of untwisted parts in the yarn to exceed a certain amount.

Patent Document 2 also proposes a fusion-bonded false twist textured yarn that can produce knitted and woven fabrics with rich textures by shortening the untwisted length of the fusion-bonded draw false twist textured yarn.

These false twisted yarns have untwisted and untwisted parts, but the yarn after the false twisting process has a nearly uniform thickness, and there is only a slight change in appearance, so it is difficult to say that the yarn as a whole has a good texture. Therefore, Patent Document 3 proposes a false twisted yarn that has a thin untwisted part in which part of the raw yarn is heat-treated to fuse and retain the twist at the time of twisting, and a thick over-untwisted part in which the other part of the raw yarn is excessively untwisted to give it volume.

However, none of the false twist textured yarns have been able to produce fabrics with sufficient stiffness and a linen-like feel through weaving.

Japanese Unexamined Patent Publication No. 55-67025 Japanese Patent Application Publication No. 8-100340 JP 2002-161445 A

The present invention aims to solve the problems described above, and its technical objective is to provide a false twist textured yarn that can produce a woven fabric with sufficient firmness and a linen-like feel.

The inventors conducted extensive research to solve the above problems, and discovered that the problems could be solved by setting the length in the yarn longitudinal direction, the length in the yarn width direction, and the number of the untwisted and untwisted parts within specific ranges, thus arriving at the present invention.

That is, the present invention provides the following.
(1) A false twist textured yarn made of polyester filaments, in which untwisted and untwisted sections exist alternately in the longitudinal direction of the yarn, the false twist textured yarn having 40 to 110 untwisted sections each having a length of 0.3 to 12 mm in the longitudinal direction of the yarn per meter of the yarn, and a length ratio of the untwisted sections to the untwisted sections in the width direction of the yarn (untwisted sections/untwisted sections) of 1/3 to 1/14.
(2) A false twisted yarn according to (1), in which the untwisted portions have untwisted portions A having a length of 0.3 to less than 3 mm and untwisted portions B having a length of 3 to 12 mm, and there are 30 to 85 untwisted portions A per meter of the yarn, and 3 to 25 untwisted portions B per meter of the yarn.
(3) False twisted yarn according to (1) or (2), in which the ratio of the total length of the untwisted portions per meter of the yarn to the total length of the untwisted portions per meter of the yarn is total length of untwisted portions/total length of untwisted portions = 1/3 to 1/10.
(4) A false twist textured yarn according to any one of (1) to (3), wherein the single fibers constituting the false twist textured yarn have a single fiber fineness of 5 to 20 dtex and a multi-lobal shape having 3 to 8 convex portions in a cross section perpendicular to the longitudinal direction of the fiber.

The false twist textured yarn of the present invention has alternating untwisted and untwisted sections in the longitudinal direction of the yarn, and the lengths of the untwisted and untwisted sections in the longitudinal direction of the yarn, the lengths in the width direction, and the number of sections satisfy specific ranges, so that by weaving it, it is possible to obtain a woven fabric that has sufficient firmness, a linen-like feel, and excellent dyeability.

FIG. 1 is an enlarged schematic diagram showing one embodiment of the false twist textured yarn of the present invention. FIG. 1 is a process diagram showing an example of a method for producing false twist textured yarn of the present invention. FIG. 2 is a process diagram showing a method for producing false twist textured yarn of a comparative example.

The false twist textured yarn of the present invention will now be described with reference to the drawings.
FIG. 1 is a partial enlarged view of the false twist textured yarn of the present invention, in which FIG. 1( a ) is an enlarged view of an untwisted portion 1 and FIG.
The false twist textured yarn of the present invention is formed by false twisting a raw yarn, which is a highly oriented undrawn yarn or a drawn yarn, so that untwisted portions 1 and untwisted portions 2 are formed alternately in the yarn longitudinal direction.
The untwisted portion 1 is formed by heating and melting a part of the raw yarn while twisting it, and fusing the single fibers that make up the raw yarn to each other, thereby maintaining the twist in the twisted state. The untwisted portion 2 is formed by excessively untwisting the unfused parts of the raw yarn during false twisting, and has a large bulge due to the widening of the spaces between the single fibers.

The untwisted portions 1 and untwisted portions 2 are alternately present in the longitudinal direction of the yarn. The length of the untwisted portions 1 in the longitudinal direction of the yarn is 0.3 to 12 mm, and the number of untwisted portions 1 present per meter of the yarn is 40 to 110/m. If the number of untwisted portions 1 is less than 40/m or exceeds 110/m, the resulting woven fabric will lack firmness and linen-like texture (crispness).
In particular, in order to obtain a woven fabric having excellent stiffness and a linen-like texture, it is preferable that the false twisted yarn of the present invention has, as the untwisted portion 1, 35 to 85 untwisted portions A each having a length of 0.3 to less than 3 mm per meter of yarn, and 5 to 25 untwisted portions B each having a length of 3 to 12 mm per meter of yarn.

The ratio of the total length of the untwisted sections 1 per meter of yarn to the total length of the untwisted sections 2 per meter of yarn is preferably 1/3 to 1/10, more preferably 1/4 to 1/8, i.e., total length of the untwisted sections/total length of the untwisted sections.

Furthermore, the false twisted yarn of the present invention has a ratio of the length of the untwisted section to the untwisted section in the yarn width direction (untwisted section/untwisted section) of 1/2 to 1/14, preferably 1/3 to 1/12.

As described above, the false twisted yarn of the present invention has a ratio of the length in the longitudinal direction of the yarn to the length in the transverse direction of the untwisted portion where the single fibers are fused to each other and the untwisted portion where the single fibers are not fused to each other within the above range, so that the appearance of the entire yarn is complex and varied, and when made into a fabric, it is possible to present a linen-like texture and stiffness. Therefore, if the ratio of these lengths is outside the above range, the resulting fabric will lack the linen-like texture and stiffness.

The length and number of untwisted portions in the yarn longitudinal direction, and the lengths of the untwisted portions and untwisted portions in the yarn width direction in the false twist textured yarn described above are measured as follows.
An initial load of 0.0882 cN/dtex is applied to the false twisted yarn, and a mark is made at 1 m. Next, under a light load of 0.00882 cN/dtex, the length of the untwisted portion is measured using an optical microscope (Keyence Corporation's Microscope VHX-900) and the number of untwisted portions is calculated, dividing the length per meter of yarn into untwisted portions A with lengths of 0.3 to less than 3 mm and untwisted portions B with lengths of 3 to 12 mm. At this time, the yarn widths of the untwisted and untwisted portions are also measured. Measurements are made for N=5, and the average value is calculated.
The yarn width of the untwisted and untwisted portions is measured at the widest yarn width portion when visually observed.

The false twist textured yarn of the present invention is made of polyester filaments. The polyester filaments may be made of polyesters such as polyalkylene terephthalates. Specific examples include polyethylene terephthalate (PET), polybutylene terephthalate, and polytrimethylene terephthalate. In consideration of viscosity, thermal properties, compatibility, and the like, aromatic dicarboxylic acids such as isophthalic acid and 5-sulfoisophthalic acid, aliphatic dicarboxylic acids such as adipic acid, succinic acid, suberic acid, sebacic acid, and dodecanedioic acid, aliphatic diols such as ethylene glycol, propylene glycol, 1,4-butanediol, and 1,4-cyclohexanedimethanol, hydroxycarboxylic acids such as glycolic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxypentanoic acid, hydroxyheptanoic acid, and hydroxyoctanoic acid, and aliphatic lactones such as ε-caprolactone may be copolymerized.

The polyester filaments may also contain additives such as antistatic agents, antibacterial agents, and deodorants to provide functionality.

The single fibers constituting the false twist textured yarn of the present invention preferably have a single fiber fineness of 5 to 20 dtex, and more preferably 8 to 18 dtex. Furthermore, these single fibers preferably have a multi-lobed shape with 3 to 8 convex portions in a cross section perpendicular to the longitudinal direction of the fiber, and more preferably have a cross-shaped cross section with 4 convex portions. In this way, the single fibers constituting the false twist textured yarn have a relatively large single fiber fineness and a cross-sectional shape with convex portions, so that the appearance of the entire yarn is complex and rich in variety.

In other words, during false twist processing, the convex portions of each single fiber intertwine like gears, and the intertwined portions do not easily separate, becoming untwisted portions, with a small length in the width direction of the yarn. On the other hand, the portions where the convex portions of each single fiber do not intertwine become untwisted portions, and since they exist without being intertwined, the convex shapes of each single fiber make them bulky and bulging, and therefore the length in the width direction of the yarn is large.

In addition, the total fineness of the false twist textured yarn of the present invention is preferably 90 to 200 dtex, and more preferably 100 to 180 dtex.

Furthermore, the crimp rate of the false twist textured yarn of the present invention is preferably 20 to 60%, and more preferably 30 to 50%. By setting the crimp rate at such a rate, the fabric will not be too fluffy or soft when woven. By achieving a good balance between the untwisted and untwisted parts, a fabric with good crispness and firmness can be obtained.

The above-mentioned crimp rate is measured as follows. After taking a skein of the false twist textured yarn with 5 windings using a measuring machine with a frame circumference of 1.125 m, the skein is hung on a stand in a free state at room temperature for a day and a night. Next, the skein is put into boiling water with a load of 0.000147 cN/dtex applied, and is subjected to a wet heat treatment for 30 minutes. Then, the skein is taken out, the moisture is lightly removed with filter paper, and the skein is left in a free state at room temperature for 30 minutes. Then, a load of 0.000147 cN/dtex and 0.00177 cN/dex (light load) are applied to the skein, and the length X is measured. Next, while the load of 0.000147 cN/dtex is still applied, a load of 0.044 cN/dtex (heavy load) is applied instead of the light load, and the length Y is measured. Then, the crimp rate is calculated according to the following formula.
Crimp rate (%) = (Y-X)/Y x 100
The crimp rate is measured with N=5, and the average is taken as the crimp rate.

The false twist textured yarn of the present invention preferably has a torque of 90 to 140 T/M, and more preferably 100 to 130 T/M. By setting the torque in this range, excessive tangling does not occur in the false twist textured yarn, and the occurrence of burrs and wrinkles is suppressed when passing through the process of forming a woven fabric, making it possible to obtain a high-quality woven fabric with good operability without causing any trouble. Furthermore, it is preferable that the false twist textured yarn of the present invention has a Z twist.

The above torque is measured as follows. A load of 0.0294 (cN/dtex) is applied to the false twist textured yarn to prevent it from turning, and a sample of 200 cm in length is taken. Next, the sample is held almost parallel with a distance of 2 cm between both ends, and a load of 0.00294 (cN/dtex) is applied to the center (100 cm away) to form a V-shape, leaving the lower part of the V-shape in a tension-free state. At this time, the sample turns due to the residual torque, and is left until the turning stops. After the turning stops, the number of turns is measured with a twist detector, and the value obtained from this measurement is the torque number.

Next, the method for producing false twist textured yarn of the present invention will be described with reference to FIG.
The false twist textured yarn of the present invention is obtained by subjecting polyester filaments to false twist texture. As the filaments to be false twist textured, it is preferable to use a drawn yarn (FDY) obtained by melt spinning a raw polyester polymer, followed by drawing and heat treatment, or a partially oriented undrawn yarn (POY) which is melt spun and then wound up, preferably at a spinning speed of 2000 m/min to 3500 m/min.

In the present invention, the drawn yarn (FDY) preferably has an elongation of 20 to 40%, and the partially oriented undrawn yarn (POY) preferably has an elongation of 80 to 110%.

The false twisting is performed by a heat treatment heater 2 and a false twist imparting device 3 provided between a supply roller 1 and a first take-up roller 4 .
When a drawn yarn is used as the filament to be false twisted, the draw ratio may be 0.90 to 1.20, preferably 0.95 to 1.10, and when a highly oriented undrawn yarn is used, the draw ratio may be 1.10 to 1.70, preferably 1.20 to 1.50. When a drawn yarn is used, it is also preferable to perform false twisting without drawing, with a false twist overfeed ratio of 1.8 to 5.0%.

The stretch ratio and false twist overfeed rate are adjusted by the difference in roller speed between the supply roller 1 and the first take-up roller 4. When the speed of the first take-up roller 4 is faster than that of the supply roller 1, stretching occurs, and when the speed of the first take-up roller 4 is slower than that of the supply roller 1, overfeed occurs.
The overfeed rate is a value calculated by the following formula, where V1 is the yarn speed immediately before being introduced into the false twist imparting device 3, and V2 is the yarn speed immediately after passing through the false twist imparting device 3. That is, in Fig. 2, the yarn speed V1 is the speed of the supply roller 1, and the yarn speed V2 is the speed of the first take-up roller 4.
Overfeed rate (%) = {(V1 - V2) / V2} x 100

The false twist processing is preferably performed under conditions of a false twist number of 2000 to 5000 T/M, preferably 2200 to 4000 T/M, a heat treatment heater 2 temperature (false twist temperature) of 150 to 240°C, preferably 170 to 230°C, and a K value (untwisting tension/twisting tension) of 1.5 to 3.0.

In order to form untwisted sections in the resulting false twist textured yarn where the single filament yarns of the raw yarn are fused together, it is preferable to set the heat treatment heater temperature above the softening point and below the melting point of the polyester filament that forms the raw yarn. By adjusting the heat treatment heater temperature, untwisted and untwisted sections are formed in the longitudinal direction of the yarn, and the length and width of these sections can be adjusted.

Examples of false twisting devices used in false twist processing include pins, friction disks, belts, etc., with pin types being preferred.

Then, the false twist textured yarn, which has been false twisted by the heat treatment heater 2 and false twist imparting device 3 provided between the supply roller 1 and the first take-up roller 4, is wound around the winding roller 5 to obtain a package 6 of false twist textured yarn.

When the false twist textured yarn of the present invention obtained as described above is used to obtain a woven fabric, it is preferable to further twist the yarn before subjecting it to the weaving process. If the false twist textured yarn has a Z twist, the twist is preferably an S twist of 200 to 400 T/M.

In the case of fabrics using the false twist textured yarn of the present invention, the false twist textured yarn of the present invention can be used for either the warp or weft, or both, but it is preferable to use it for the warp. Among them, a blended spun yarn (20-50 count) of polyester fiber and cotton is preferable for use as the weft. Such a weft is soft and hygroscopic, and the linen-like texture of the warp and sufficient firmness combine to produce a woven fabric that is comfortable to wear.
etc.

The weave of the resulting woven fabric is not particularly limited, and examples thereof include plain weave, twill weave, satin weave, etc., and may be a multi-layer weave if necessary. Among these, plain weave is preferred.
The cover factor (CF) is not particularly limited, but is preferably 1500 to 2600. The cover factor (CF) is a numerical representation of the density of a woven or knitted fabric, and is calculated by the following formula: D=total fineness of warp yarns, E=total fineness of weft yarns.
CF = D ^1/2 x warp density (pieces/2.54 cm) + E ^1/2 x weft density (pieces/2.54 cm)

The present invention will be described in more detail below with reference to examples. Methods for measuring and evaluating various property values in the examples will be described.
(1) Length and number of untwisted parts in the yarn longitudinal direction, and length of untwisted and untwisted parts in the yarn width direction. These were measured by the method described above.
(2) Single fiber fineness, total fineness Measured based on JIS L1013 8.3.1.
(3) Crimp rate and torque Measured by the methods described above.

(4) Fabric Evaluation The stiffness and crispness of the resulting fabric (dyed cloth) were evaluated by touch, and the quality of the dyed fabric was visually evaluated on a four-point scale according to the following criteria.
<Firmness and elasticity>
◎: Very good ○: Good △: Average ×: Bad <Crispy feel (hemp-like linen touch)>
◎: Very good ○: Good △: Average ×: Bad <Quality when dyed (linen-like grain)>
◎: Very good ○: Good △: Average ×: Bad

Example 1
The feed yarn was a polyester drawn yarn (109 dtex/10 filaments) having an elongation of 34%, a single fiber fineness of 10.9 dtex, and a cross-sectional shape of the single fiber being four lobes. False twisting was performed according to the steps shown in FIG. 2 to obtain a false twisted yarn.
At this time, a spindle pin type device was used as the false twist imparting device 3, and false twist processing was performed under the following conditions: processing speed (first roller speed): 113.2 m/min, false twist temperature (heat treatment heater temperature): 220° C., false twist overfeed rate: 3.92%, false twist number: S twist, 2557 T/M, K value: 2. The twisting tension was measured between the heat treatment heater 2 and the false twist imparting device 3, and the untwisting tension was measured between the false twist imparting device 3 and the first take-up roller 4.

The resulting false twist textured yarn (117 dtex/10 filaments) was a crimped yarn (crimp rate 38.7%) having untwisted and untwisted portions, and the length, width and number of the untwisted and untwisted portions were as shown in Table 1.
This false twist textured yarn was further twisted (S-300T/M) and used as the warp yarn, and a blended spun yarn of 30 count polyester fiber and cotton yarn was used as the weft yarn to weave a plain weave fabric with a warp density of 84 threads/2.54 cm and a weft density of 66 threads/2.54 cm.

The resulting fabric was scoured with 2 g/l of a nonionic surfactant (Sunmol FL, manufactured by Nicca Chemical) at 80° C. for 20 minutes and pre-set at 180° C. for 30 minutes.
Next, the fabric was dyed under the following dyeing conditions and finished at 170° C. to obtain a fabric with a warp density of 87 threads/2.54 cm, a weft density of 87 threads/2.54 cm, and a cover factor of 1698. The fabric obtained was very excellent in firmness and crispness, and had excellent dyeing quality with a linen-like heathered feel.
(Dyeing conditions)
Dye: Dianix Blue UN-SE (manufactured by Dianix) 1% o.m.f
Auxiliary agent: Nikka Sunsalt SN-130 (manufactured by Nicca Chemical Co., Ltd.) 0.5 g/L
: Acetic acid 0.2cc/L
・Temperature x time: 130℃ x 30 minutes ・Bath ratio: 1:30

Example 2
A highly oriented polyester undrawn yarn (178 dtex/10 filaments) having an elongation of 94%, a single fiber fineness of 17.8 dtex, and a cross-sectional shape of four lobes was used as the supply yarn. Then, false twisting was performed according to the process shown in FIG. 2 to obtain a false twisted yarn.
At this time, the same procedure as in Example 1 was carried out, except that drawing was carried out during false twisting and the false twisting conditions were changed to those shown in Table 1.
The properties of the resulting false twist textured yarn are shown in Table 1.
The false twist textured yarn thus obtained was used to weave in the same manner as in Example 1, except that the warp density and weft density were changed to those shown in Table 1, to obtain a plain weave fabric.
The resulting plain weave fabric was then subjected to the same scouring and dyeing processes as in Example 1 to obtain a woven fabric.
The resulting woven fabric had excellent stiffness and crispness, and also had excellent dyeing quality with a linen-like flecked look.

Example 3
False twisting was carried out in the same manner as in Example 1, except that the same supply yarn as in Example 1 was used and the false twist overfeed rate was changed to 2%.
The properties of the resulting false twist textured yarn are shown in Table 1.
The false twist textured yarn thus obtained was used to weave in the same manner as in Example 1, except that the warp density and weft density were changed to those shown in Table 1, to obtain a plain weave fabric.
The resulting plain weave fabric was then subjected to the same scouring and dyeing processes as in Example 1 to obtain a woven fabric.
The number of untwisted portions A and B in the resulting false twist textured yarn was less than the preferred range, and therefore the fabric obtained using this false twist textured yarn had good stiffness, crispness and dyeing quality.

Example 4
The supply yarn was a polyester drawn yarn (54 dtex/10 filaments) having an elongation of 32%, a single fiber fineness of 5.4 dtex, and a cross-sectional shape of the single fiber being four-lobed. False twisting was carried out in the same manner as in Example 1, except that the false twisting temperature was changed to 180° C., according to the process shown in FIG.
The properties of the resulting false twist textured yarn are shown in Table 1.
The false twist textured yarn thus obtained was used to weave in the same manner as in Example 1, except that the warp density and weft density were changed to those shown in Table 1, to obtain a plain weave fabric.
The resulting plain weave fabric was then subjected to the same scouring and dyeing processes as in Example 1 to obtain a woven fabric.
The resulting woven fabric had good stiffness, crispness and dyeing quality.

Example 5
The same supply yarn as in Example 2 was used, and false twisting was carried out in the same manner as in Example 2, except that the untwisting tension and twisting tension in the false twist imparting device were changed to the values shown in Table 1.
The properties of the resulting false twist textured yarn are shown in Table 1.
The false twist textured yarn thus obtained was then woven in the same manner as in Example 2 to obtain a plain weave fabric.
The resulting plain weave fabric was then subjected to the same scouring and dyeing processes as in Example 1 to obtain a woven fabric.
The resulting woven fabric had good stiffness, crispness and dyeing quality.

Comparative Example 1
The same procedure as in Example 1 was repeated, except that the same supply yarn as in Example 1 was used, drawing was performed during false twisting according to the process shown in Fig. 3, heat treatment was performed with the second heat treatment heater 7 provided between the false twist imparting device 3 and the first take-up roller 4, and the false twist processing conditions were changed to those shown in Table 1. The heat treatment overfeed rate shown in Table 1 is calculated from the speeds of the first take-up roller 4 and the second take-up roller 8.
The property values of the false twist textured yarn obtained are shown in Table 1. The false twist textured yarn obtained was a flat yarn having no untwisted or untwisted parts and no torque.
The false twist textured yarn thus obtained was used to weave in the same manner as in Example 1, except that the warp density and weft density were changed to those shown in Table 1, to obtain a plain weave fabric.
The resulting plain weave fabric was then subjected to the same scouring and dyeing processes as in Example 1 to obtain a woven fabric.
The resulting woven fabric was stiff and had poor stiffness and crispness.

Comparative Example 2
The same supply yarn as in Example 1 was used, and false twisting was carried out in the same manner as in Example 1, except that the false twisting temperature was changed to 250°C.
The property values of the obtained false twist textured yarn are shown in Table 1. In the obtained false twist textured yarn, the single fibers were fused to each other, and it was a flat yarn having no untwisted or untwisted parts and having neither crimp nor torque.
The false twist textured yarn thus obtained was used to weave in the same manner as in Example 1, except that the warp density and weft density were changed to those shown in Table 1, to obtain a plain weave fabric.
The resulting plain weave fabric was then subjected to the same scouring and dyeing processes as in Example 1 to obtain a woven fabric.
The resulting woven fabric was stiff and inferior in all respects, including stiffness, crispness and dyeing quality.

Comparative Example 3
The same supply yarn as in Example 1 was used and false twisted to obtain a false twist textured yarn.
At this time, the same procedure as in Example 1 was carried out, except that drawing was carried out during false twisting and the false twisting conditions were changed to those shown in Table 1.
The property values of the resulting false twist textured yarn are shown in Table 1. The resulting false twist textured yarn had no untwisted parts.
The false twist textured yarn thus obtained was used to weave in the same manner as in Example 1, except that the warp density and weft density were changed to those shown in Table 1, to obtain a plain weave fabric.
The resulting plain weave fabric was then subjected to the same scouring and dyeing processes as in Example 1 to obtain a woven fabric.
The obtained woven fabric had a different surface feel and texture than the false twisted yarn because the false twisted yarn did not have any untwisted parts, and was inferior in all respects, including stiffness, crispness, and dyeing quality.

Comparative Example 4
The same false twisting process as in Example 2 was carried out using the same supply yarn as in Example 2, except that the false twist draw ratio was changed to 1.55 and the untwisting and twisting tensions were changed to those shown in Table 1.
The property values of the resulting false twist textured yarn are shown in Table 1. The resulting false twist textured yarn only had untwisted parts A, and the number of these was small.
The false twist textured yarn thus obtained was used to weave in the same manner as in Example 1, except that the warp density and weft density were changed to those shown in Table 1, to obtain a plain weave fabric.
The resulting plain weave fabric was then subjected to the same scouring and dyeing processes as in Example 1 to obtain a woven fabric.
The resulting woven fabric was inferior in stiffness and crispness.

Comparative Example 5
The same supply yarn as in Example 2 was used, and false twisting was carried out in the same manner as in Comparative Example 4, except that the false twisting temperature was changed to 190°C.
The property values of the resulting false twist textured yarn are shown in Table 1. The resulting false twist textured yarn only had untwisted parts A, and the number of these was small.
The false twist textured yarn thus obtained was used to weave in the same manner as in Example 1, except that the warp density and weft density were changed to those shown in Table 1, to obtain a plain weave fabric.
The resulting plain weave fabric was then subjected to the same scouring and dyeing processes as in Example 1 to obtain a woven fabric.
The resulting woven fabric was inferior in stiffness and crispness.

Comparative Example 6
The same supply yarn as in Example 2 was used, and false twisting was performed in the same manner as in Example 2, except that the false twisting temperature was changed to 240° C., the false twisting draw ratio was changed to 1.35, and the untwisting and twisting tensions were changed to those shown in Table 1.
The property values of the resulting false twist textured yarn are shown in Table 1. The resulting false twist textured yarn had a large number of untwisted portions A and B.
The false twist textured yarn thus obtained was used to weave in the same manner as in Example 1, except that the warp density and weft density were changed to those shown in Table 1, to obtain a plain weave fabric.
The resulting plain weave fabric was then subjected to the same scouring and dyeing processes as in Example 1 to obtain a woven fabric.
The resulting woven fabric was too stiff due to the high false twist temperature, and had poor stiffness and crispness, and was also inferior in dyeing quality.

Comparative Example 7
The same false twisting process as in Example 2 was carried out using the same supply yarn as in Example 2, except that the false twist number, untwisting and twisting tension were changed to those shown in Table 1.
The property values of the obtained false twist textured yarn are shown in Table 1. The obtained false twist textured yarn had an open untwisted portion and a large ratio of the length of the untwisted portion to the length of the untwisted portion in the yarn width direction.
The false twist textured yarn thus obtained was used to weave in the same manner as in Example 1, except that the warp density and weft density were changed to those shown in Table 1, to obtain a plain weave fabric.
The resulting plain weave fabric was then subjected to the same scouring and dyeing processes as in Example 1 to obtain a woven fabric.
The resulting woven fabric was inferior in all respects, including stiffness, crispness and dyeing quality.

1 Supply roller
2 Heat treatment heater 3 False twist imparting device 4 First take-up roller 5 Winding roller 6 Package of false twisted yarn 7 Second heat treatment heater 8 Second take-up roller

Claims (4)

The false twist textured yarn is made of polyester filaments and has untwisted and untwisted sections alternately present in the longitudinal direction of the yarn, the false twist textured yarn having 40 to 110 untwisted sections each having a length of 0.3 to 12 mm in the longitudinal direction of the yarn per meter of the yarn, and a length ratio of the untwisted sections to the untwisted sections in the width direction of the yarn (untwisted sections/untwisted sections) of 1/3 to 1/14. The false twisted yarn according to claim 1, which has as the untwisted portions untwisted portion A having a length of 0.3 to less than 3 mm and untwisted portion B having a length of 3 to 12 mm, and has 30 to 85 untwisted portions A per 1 m of yarn and 3 to 25 untwisted portions B per 1 m of yarn. The false twisted yarn according to claim 1 or 2, in which the ratio of the total length of the untwisted parts per meter of yarn to the total length of the untwisted parts per meter of said yarn is 1/3 to 1/10 (total length of untwisted parts/total length of untwisted parts). 4. The false twist textured yarn according to claim 1, wherein the single fibers constituting the false twist textured yarn have a single fiber fineness of 5 to 20 dtex, and a cross section perpendicular to the longitudinal direction of the fiber has a multi-lobal shape having 3 to 8 convex portions.