JP7521255B2 - Polyester false twist yarn and knitted fabric - Google Patents

Description

The present invention relates to polyester false-twist yarn that has improved snag resistance, a problem that has been a problem with worsted polyester false-twist yarn, and has a natural heathered feel, fullness, and a subdued luster, and to woven and knitted fabrics made from the same.

Conventionally, polyester yarn has been used as a replacement for natural wool materials in suits, jackets, slacks, etc., because it has a higher firmness and wrinkle resistance than other synthetic fibers, and various worsted polyester processed yarns with a wool-like appearance, texture, and luster have been developed. A well-known conventional technique for imparting a worsted appearance and texture to polyester yarn is a yarn in which each filament constituting the polyester yarn is provided with an unstretched portion (thick portion) and a stretched portion (detailed portion) in the length direction, and the thick portion and the detailed portion are dispersed within the filament yarn (see Patent Document 1). However, although the above-mentioned yarn is superior in terms of a heathered appearance and the like compared to polyester false-twisted yarn that has not been subjected to such processing, it does not have the natural heathered feel and fullness of wool, and the glittering luster peculiar to synthetic fibers due to the cross section being flattened by false twisting has been an issue.

As a technology that combines the above-mentioned thick-thin drawing technology with irregular cross-section filament yarn, polyester multifilament yarn in which irregular cross-section filaments with recesses are unevenly drawn (see Patent Document 2) and polyester multifilament yarn in which two or more different types of monofilaments with multi-lobed cross-section shapes are dispersed and mixed (see Patent Document 3) have been proposed. These yarns have excellent water absorbency and a refreshing feel, but do not have a natural heathered feel or a fluffy feel.

On the other hand, in a core-sheath type mixed fiber processed yarn made of two kinds of polyester filament yarns with different fineness, a polyester mixed fiber processed yarn in which a thick section is provided in the sheath yarn to give it a natural heathered look (see Patent Document 4) and a composite false-twisted yarn in which a thick and thin false-twisted yarn made of ionic dyed yarn is intertwined with a thick and thin false-twisted yarn made of non-ionic dyed yarn, have been proposed, which have a multicolored cassamla effect, an uneven texture, and a natural, spun-like feel (see Patent Document 5). Although these techniques can give a natural heathered look and fullness, there is a problem in that the two types of filaments separate during repeated washing, deteriorating snag resistance, making them difficult to apply to outerwear.

As such, conventional technology has been unable to produce processed yarn that satisfies the natural heathered feel, fluffiness, and subtle luster of combed yarn, as well as the quality issue of snag resistance and washing durability.

Japanese Unexamined Patent Publication No. 181316/1983 Japanese Patent Application Publication No. 4-91219 Japanese Patent Application Publication No. 8-218241 JP 2003-119640 A JP 2001-20144 A

The object of the present invention is to provide a false-twisted yarn that improves the snag resistance after repeated washing, which has been an issue with worsted polyester false-twisted yarn, and that has a natural heathered feel, fullness, and a subdued luster, and a woven or knitted fabric made from the same.

In order to solve such problems, the polyester false twist yarn of the present invention has any one of the following configurations.
(1) A polyester false-twisted yarn having thickness variations in the length direction, characterized in that the crimp rate is 26 to 45% and the local single yarn length difference is 5 to 20%.
(2) A polyester false twist yarn as described in (1) above, characterized in that there is a phase difference in the thick/thin unevenness between single yarns.
(3) The polyester false twist yarn according to (1) or (2) above, characterized in that it is made of a homopolymer.
(4) A polyester false twist yarn according to any one of (1) to (3) above, characterized in that the cross section of a single yarn has 6 to 10 recesses.
(5) The polyester false twist yarn according to any one of (1) to (4) above, characterized in that the degree of entanglement is 50 to 150 pcs/m.
(6) A woven or knitted fabric, characterized in that the false twist yarn according to any one of (1) to (5) above is used.
(7) The woven or knitted fabric according to (6) above, characterized in that the result of a snag test according to JIS L 1058: 2011 7.2 after 20 washes is grade 3 or higher.

According to the present invention, it is possible to obtain polyester false-twist yarn that has improved snag resistance after repeated washing, a natural heathered feel, a fluffy feel, and a subdued luster, and a woven or knitted fabric made from the same.

FIG. 2 is a schematic cross-sectional view of a single yarn constituting a polyester false twist yarn.

The polymers constituting the polyester false twist yarn of the present invention include aromatic polyesters such as polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate, and aliphatic polyesters such as polylactic acid and polyglycolic acid. Among these, polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate are preferred because they have excellent mechanical properties and durability of the fiber and have robust crimp. More preferred is polyethylene terephthalate, which increases the yarn strength of the unstretched portion.

As the polyethylene terephthalate, a polyester consisting of 90 mol % or more of repeating units of ethylene terephthalate, with terephthalic acid as the main acid component and ethylene glycol as the main glycol component, can be used. In addition, other copolymerizable components capable of forming ester bonds may be included within a range that does not impair the effects of the present invention. Examples of copolymerizable compounds include dicarboxylic acids such as isophthalic acid, cyclohexanedicarboxylic acid, adipic acid, dimer acid, sebacic acid, and sulfonic acid.

The polyester false-twisted yarn of the present invention has thickness unevenness in the length direction between the unstretched parts (thick parts) and the stretched parts (details). With this configuration, when it is made into a woven or knitted fabric, the thick parts are dyed dark and the details are dyed light, resulting in a mottled appearance and a fluffy feel. Here, a false-twisted yarn that does not have thickness unevenness in the length direction has a plain surface appearance and does not have a fluffy feel.

In the present invention, it is preferable to provide a phase difference in the thick and thin unevenness between single yarns, i.e. to distribute the positions of the thick and thin parts between single yarns in the length direction. This allows the incident light to be diffusely reflected, further reducing glare. False-twist yarns that have no phase difference in the thick and thin unevenness between single yarns are prone to producing the glare that is characteristic of synthetic fibers.

It is important that the polyester false-twisted yarn of the present invention has a crimp rate of 26 to 45%. Because the polyester false-twisted yarn of the present invention has unstretched portions (thick portions), the crimp imparted to the low-oriented unstretched portions tends to be weaker than the stretched portions (details). However, if the false-twisted yarn can have a crimp rate of 26% or more, it can impart high stretchability and a fluffy feel to woven and knitted fabrics. Here, if the crimp rate is less than 26%, the fluffy feel is insufficient and it is not possible to obtain a worsted texture. Furthermore, if the crimp rate exceeds 45%, the single yarn crimp in the thick portions will protrude to the surface of the woven fabric, reducing snag resistance.

It is also possible to use a bimetallic yarn made of, for example, polyethylene terephthalate and polytrimethylene terephthalate as the polyester false twist yarn of the present invention, but as this tends to cause excessive crimping and reduce snag resistance, a polyester false twist yarn made of a homopolymer is preferred.

It is important that the polyester false-twist yarn of the present invention has a local single-yarn length difference of 5 to 20%. The local single-yarn length difference here means the difference in the length of the single yarns that compose the false-twist yarn when viewed at a short length, specifically, the local single-yarn length difference of any 5 cm. In the past, in order to give a natural heathered feel and fullness to woven and knitted fabrics, a method was considered in which a core-sheath type composite yarn made of two or more types of yarn was used and a difference in the length of the yarns that compose the core and the sheath was given. However, with this method, the intertwining is easily removed after repeated washing, and the filaments that compose the sheath are easily exposed to the surface of the woven and knitted fabric, which reduces the snag resistance. In addition, when two types of yarn are combined, the mixed fibers are easily uneven, and streaks due to dyeing differences are easily caused in the woven and knitted fabric. In contrast, in the present invention, by making the single yarns that make up the polyester false twist yarn have a local single yarn length difference within the above-mentioned range, not only does it produce a natural heathered feel and a fluffy feel, it also produces excellent snag resistance, and furthermore, it is possible to prevent the occurrence of streak defects due to unevenness in the mixed fibers and differences in dyeing.

In the present invention, a local single yarn length difference of 5% or more can impart a natural heathered appearance and a fluffy feel to the woven or knitted fabric. Furthermore, in a woven or knitted fabric in which there is a localized single yarn length difference, filaments are less likely to protrude onto the surface of the woven or knitted fabric even after repeated washing, and the fabric has good snag resistance. If the single yarn length difference is less than 5%, the fabric will have a monotonous heathered appearance and a poor fluffy feel. On the other hand, if the single yarn length difference is more than 20%, the single yarn crimp in the thick part will protrude onto the surface of the fabric, and snag resistance will decrease.

In order to realize such differences in the length of single yarns, for example, by dispersing the phase of the thickness unevenness of the single yarns in the length direction between the single yarns as described above, the incident light can be diffusely reflected, and glare can be reduced.

In addition, in the polyester false twist yarn of the present invention, it is preferable that the local single yarn length difference is not a yarn length difference caused by combining two types of yarn, but a local single yarn length difference caused by one type of yarn.

In the polyester false twist yarn of the present invention, the cross section of the single yarn constituting it is preferably a non-circular cross section having 6 to 10 recesses. By having 6 to 10 recesses in the cross section of the single yarn, incident light can be diffusely reflected and glare can be suppressed. In addition, by having recesses, the single yarn is more likely to break apart during hot pin drawing, and as a result, the phase of the thick part between the single yarns is shifted, and local single yarn length differences are more likely to occur. Here, if there are less than 6 recesses, glare is more likely to occur, and the appearance is more likely to be monotonous and mottled, and the sense of fullness is also likely to decrease, which is not preferable. On the other hand, if there are more than 10 recesses, the depth of the recesses becomes shallow and the effect of reducing glare is smaller, which is not preferable. A more preferable number of recesses is 7 to 9. Note that the recesses refer to the recesses (U) that exist between the contact points S1 and S2 when a straight line T1 is drawn that touches the cross-sectional contour at multiple contact points S1 and S2 in the fiber cross-sectional view as shown in FIG. 1.

The polyester false twist yarn of the present invention may contain inorganic fine particles, and the inorganic fine particle content is preferably 0.3 to 3.0% by mass of the polyester false twist yarn, since glare can be suppressed. Here, if the inorganic fine particle content is less than 0.3% by mass, glare tends to be strong, friction between filaments increases, filaments tend to fly out during repeated washing, and snag resistance tends to decrease, which is undesirable. If the inorganic fine particle content exceeds 3.0% by mass, it becomes difficult to produce dark colors during dyeing, which is undesirable. A more preferable inorganic fine particle content is 0.5 to 2.5% by mass. Note that any inorganic particles such as titanium dioxide, silica, kaolinite, and alumina can be used as the inorganic fine particles, but titanium oxide, which has a high refractive index and a high light scattering effect, is preferable.

The polyester false twist yarn of the present invention preferably has a boiling water shrinkage rate of 4 to 9%. If the boiling water shrinkage rate exceeds 9%, the thick part of the single yarn is likely to pop out during repeated washing, and snag resistance decreases, which is not preferable. Also, if the boiling water shrinkage rate is less than 4%, the sense of fullness decreases, which is not preferable.

The total fineness of the polyester false twist yarn of the present invention is preferably 50 to 450 dtex in order to impart firmness to the woven or knitted fabric. If the total fineness is outside the above preferred range, the fabric may not have sufficient firmness when made into clothing, and glare may be noticeable.

On the other hand, the fineness of the single yarns constituting the polyester false twist yarn is preferably 0.5 to 10 dtex in order to impart firmness to the woven or knitted fabric. If the single yarn fineness is outside the above-mentioned preferred ranges, the single yarn crimp in the thick part is likely to protrude to the surface of the woven fabric even after repeated washing, and snags may easily occur.

The degree of entanglement of the polyester false twist yarn of the present invention is preferably 50 to 150 pcs/m. If the degree of entanglement is less than 50 pcs/m, the single yarn crimp in the thick part is likely to pop out onto the surface of the woven fabric after repeated washing, which is undesirable. If the degree of entanglement is more than 150 pcs/m, it is undesirable because it becomes difficult to realize the above-mentioned local single yarn length difference.

The polyester false twist yarn of the present invention can be twisted in a later process without any problems. In order to achieve both snag resistance and a fluffy feel, the preferred number of twists is 100 to 1000 T/m, and more preferably 200 to 700 T/m.

Next, we will explain the manufacturing method of the polyester false twist yarn and woven/knitted fabric of the present invention.

First, when spinning the raw yarn that will become the base yarn of the polyester false twist yarn of the present invention, it is preferable to spin a highly oriented undrawn yarn. Here, in order to emphasize the difference in thickness between single yarns during hot pin drawing and to easily generate localized differences in single yarn length, a low spinning speed is preferable, and the preferred spinning speed is 2500 to 3100 m/min.

To turn a highly oriented undrawn yarn into the false-twisted yarn of the present invention, a low-magnification heat treatment and drawing is performed with a hot pin before false-twisting, to impart thick and thin unevenness to the single yarn and to generate localized differences in the single yarn length. The preferred hot pin drawing conditions are 1.2 to 1.6 times. In addition, to generate localized differences in the single yarn length, a lower hot pin temperature is preferred, with the preferred conditions being in the range of 65 to 85°C.

Next, false twist processing is performed, and any conditions can be selected for the false twisting. Any type of twister can be used, including spindle, friction disk, and belt nip types, but a friction disk type is preferred, as it allows false twisting at high speed and causes relatively little popping out of single yarn crimp.

When using a contact heater, a false twist temperature of 170 to 215°C is preferable because it creates a strong crimp that does not deteriorate with repeated washing.

Regarding the number of false twists, it is preferable to set the false twist coefficient (number of false twists (T/M)×fineness (dtex) ^0.5 ) within the range of 27,000 to 33,000 in order to impart strong crimp that does not deteriorate with repeated washing.

Interlacing can also be done before or after false twisting using an interlace nozzle. Taking cost into consideration, it is preferable that the interlacing pressure is 0.1 to 0.6 (MPa).

The faster the yarn processing speed, the higher the productivity, which is preferable, but when stable processing is taken into consideration, a speed of 100 to 800 (m/min) is preferable.

The false twist yarn of the present invention thus produced is made into a woven or knitted fabric using known weaving and knitting methods. Any known weaving or knitting structure can be used. In the present invention, woven and knitted fabrics are collectively referred to as "woven or knitted fabrics." There are no restrictions on the structure or density of the woven or knitted fabrics of the present invention.

Examples of looms used for weaving include commonly used normal looms, rapiers, water jet looms, air jet looms, etc., and there are no particular limitations on which looms can be used.

When knitting, commercially available knitting machines such as circular knitting machines, tricot machines, and raschel machines can be used.

When the false twist yarn of the present invention is used as at least a part of the knitting yarn, it is necessary to optimize the tension of each yarn during knitting. Any knitting structure can be designed, including plain, smooth, punch, rib, and half structures.

Next, we will explain the dyeing process applied to woven and knitted fabrics using the false-twisted yarn of the present invention. The dyeing process can be carried out in accordance with the dyeing process and conditions for woven and knitted fabrics using general polyester false-twisted yarn. In order to fully express the false-twisted crimp, it is preferable that the relaxation heat treatment be a high-temperature, high-pressure liquid flow relaxation process at 120°C or higher, and that the woven and knitted fabrics are given a kneading effect.

In addition, to suppress shrinkage during washing, it is preferable to set the intermediate set temperature to 170°C or higher and 210°C or lower. By setting the intermediate set temperature within the above preferred range, filaments can be prevented from fusing.

In the present invention, in order to obtain a soft feel, the woven or knitted fabric may be subjected to alkali weight loss, but the preferred weight loss rate is 15% or less. If the weight loss rate is within the above preferred range, pilling is unlikely to occur even after repeated washing.

The woven or knitted fabric of the present invention preferably has a result of grade 3 or higher in the snag test according to JIS L 1058:2011 7.2 after 20 washes. This makes the woven or knitted fabric less susceptible to snagging even after repeated washing, and is highly durable and suitable for use as an outerwear material.

The present invention will be explained in more detail below with reference to the following examples.

(1) Fineness Using a measuring machine with a frame circumference of 1.0 m, 100 skeins were prepared, and the fineness was measured according to the following formula.
Fineness (dtex) = weight of skein for 100 times (g) x 100

(2) Elongation The sample was measured using a tensile tester (Orientec "TENSILON" UCT-100) under the constant-speed elongation conditions specified in JIS L 1013 (2010) 8.5.1 Standard Time Test. The gripping distance was 20 cm, the tensile speed was 20 cm/min, and the number of tests was 10. The breaking elongation was determined from the elongation at the point showing the maximum strength in the SS curve.

(3) Degree of entanglement The degree of entanglement is the number of entangled parts per meter under a tension of 0.1 cN/dtex. A pin was inserted into the non-entangled part of the yarn under a tension of 0.02 cN/dtex, and the pin was moved up and down in the longitudinal direction of the yarn over 1 m under a tension of 0.1 cN/dtex. The part that moved without resistance was taken as a non-entangled part, and the distance traveled was recorded. The part where the pin stopped was taken as an entangled part. This operation was repeated 30 times, and the degree of entanglement per meter was calculated from the average distance of the non-entangled parts.

(4) Shrinkage The yarn was wound 10 times around a measuring machine with a circumference of 0.8 m under a tension of 90 mg/dtex to take a skein, and then hung on a rod of 2 cm or less and left for about 24 hours. The skein was wrapped in gauze, treated with hot water at 90°C for 20 minutes under no tension, and then hung on a rod of 2 cm or less and left for about 12 hours. One end of the skein after leaving was hung on a hook, and the other end was subjected to an initial load and a measurement load, and the skein was left for 2 minutes. The initial load (g) at this time was 2 mg/dtex, the measurement load (g) was 90 mg/dtex, and the water temperature was 20 ± 2°C. The inner length of the left skein was measured and designated as L. Furthermore, the measurement load was removed and the skein was left for 2 minutes with only the initial load, and the inner length of the left skein was measured and designated as L1. The shrinkage was calculated using the following formula, and this operation was repeated 5 times to determine the average value.
Crimp rate (%) = {(L-L1)/L} x 100

(5) Boiling water shrinkage was determined based on JIS L 1013 (2010) 8.18.1 Hank dimensional change rate (Method A).

(6) Number of recesses The textured yarn was cut in the fiber cross-sectional direction at a thickness of 5 μm, and then a cross-sectional photograph was taken with an optical microscope. In the fiber cross-sectional view, a straight line T1 was drawn that touches the cross-sectional contour at multiple contact points S1 and S2, and the number of recesses between the contact points was counted. The measurement was performed on the average of 50 filaments. The calculation was rounded off to the first decimal place.

(7) Local Single Yarn Length Difference Using the skein that had been shrunk in boiling water as described in (5), a 5 cm length was cut from an arbitrary location, taken out, and then disassembled into individual single yarns. The length of each single yarn was measured, and the single yarn length difference was calculated according to the following formula. This procedure was repeated five times and the average value was used.
Single yarn length difference (%) = (maximum length - minimum length) / minimum length x 100

(8) Snag resistance (after 20 washes)
A two-tub washing machine was used, with a liquid temperature of 40°C, a washing time of 5 minutes, rinsing at 30°C x 2 minutes x 2 times, and a spin cycle of 30 seconds. Kao's "Attack" (registered trademark) was used as the detergent at 1 g/L, with a liquid volume of 40 L and a combined weight of 830 g for the test cloth and the cotton cloth used as the guide cloth. After repeating this washing operation 20 times, a snag evaluation was performed according to JIS L 1058:2011 7.2 (clothed roller method) and a grade was determined. Grade 3 or higher is considered to be acceptable.

(9) Heathered Feel The heathered feel of the woven and knitted fabrics created in the examples was evaluated by 30 randomly selected people, and the result was determined based on the most common opinion. In the case of a tie, the lower result was used. ◎ and ○ are at a level that can be judged as acceptable.
◎: The length of the grain is not regular, and many grains can be seen in the light-dyed areas on a base of darkly dyed areas, giving it a natural grain look similar to that of natural wool.
○: The length of the grain is not regular, and many grains can be seen in the dark dyed areas on top of the light dyed areas, giving it a natural grain look.
△: The grain length is somewhat regular, giving it an artificial grain feel.
×: No grainy texture, flat surface.

(10) Fluffiness The results were based on the most common opinion given by 30 randomly selected people regarding the fluffy feel of the woven and knitted fabrics produced in the examples. In the case of a tie, the lower result was used. ◎ and ○ are at a level that can be judged as acceptable.
⊚: When the woven or knitted fabric is gripped, a very large bulge is felt.
◯: A large bulge is felt when the woven or knitted fabric is gripped.
Δ: When the woven or knitted fabric is gripped, there is a lack of volume.
×: Almost no swelling is felt when the woven or knitted fabric is gripped.

(11) Glare The glare of the woven and knitted fabrics produced in the examples was judged under a D65 light source in a light box, and the result was determined based on the most common opinion given by 30 randomly selected judges. In the case of a tie, the lower result was used. ◎ and ○ are at a level that can be judged as acceptable.
: No glare typical of synthetic fibers, and has a very calm glossy appearance.
◯: Almost no glare characteristic of synthetic fibers, and has a subdued glossy appearance.
Δ: The glossy sheen characteristic of synthetic fibers is locally observed.
×: Overall, the material has a shiny luster characteristic of synthetic fibers.

Example 1
Polyethylene terephthalate having an eight-lobe cross section and a titanium oxide content of 0.7% by mass was spun at a spinning speed of 2,8000 (m/min) to obtain a highly oriented undrawn yarn having a fineness of 275 dtex, 48 filaments, and an elongation of 160%. The highly oriented undrawn yarn was fed from a feed roller using a friction false twisting machine (ATF12, manufactured by TMT Machinery) and first subjected to low-ratio drawing of 1.5 times at 75°C with a hot pin at a processing speed of 400 m/min. Thereafter, false twisting was performed at a draw ratio of 1.1 times, a heater temperature of 200°C, and a false twist coefficient of 31,000. Thereafter, interlacing processing was performed at an entanglement pressure of 0.2 MPa to obtain a textured yarn having a fineness of 167 dtex, a crimp rate of 32%, a boiling water shrinkage rate of 4.8%, a local single yarn length difference of 9%, an entanglement number of 95/m, and a number of recesses of 8.

The yarns were then used as the warp and weft to weave a plain weave fabric on an air jet loom. The resulting woven fabric was then subjected to continuous open-weave scouring at 98°C, flow relaxation at 120°C, intermediate setting at 180°C, and dyed navy blue at 130°C using a disperse dye, and then finishing setting at 160°C to produce a product with a processed density (warp: 110 threads/2.54 cm, weft: 90 threads/2.54 cm).

The resulting fabric had a natural heathered look similar to that of natural wool, was very fluffy, and had a very calm, glossy appearance. It also had excellent snag resistance even after repeated washing, making it suitable for use as a worsted outer garment.

Example 2
Polyethylene terephthalate having a hexapave cross section and a titanium oxide content of 0.7% by mass was spun at a spinning speed of 2,8000 (m/min) to obtain a highly oriented undrawn yarn having a fineness of 275 dtex, 48 filaments, and an elongation of 162%. The highly oriented undrawn yarn was then fed from a feed roller using a friction false twisting machine (ATF12, manufactured by TMT Machinery) and first subjected to low-ratio drawing of 1.5 times at a hot pin temperature of 80°C at a processing speed of 400 m/min, followed by false twisting at a draw ratio of 1.1 times, a heater temperature of 190°C, and a false twist coefficient of 30,000, and then interlacing at an entanglement pressure of 0.3 MPa to obtain a textured yarn having a fineness of 167 dtex, a crimp rate of 27%, a boiling water shrinkage rate of 6.5%, a single yarn length difference of 7%, an entanglement number of 132/m, and a number of recesses of 6.

The yarn was then twisted at 300T/M and used as the warp and weft to create a plain weave fabric on an air jet loom. The resulting woven fabric was then subjected to continuous open-weave scouring at 98°C, flow relaxation at 120°C, intermediate setting at 180°C, and dyed navy blue at 130°C using a disperse dye, and then finishing setting at 160°C to create a product with a processed density (warp: 110 threads/2.54 cm, weft: 90 threads/2.54 cm).

The resulting fabric had a natural heathered look, a large sense of volume, and a subdued, lustrous appearance. It also had excellent snag resistance even after repeated washing, making it suitable for use as a worsted outer garment.

Example 3
Polyethylene terephthalate having an eight-lobe cross section and a titanium oxide content of 2.3% by mass was spun at a spinning speed of 2,8000 (m/min) to obtain a highly oriented undrawn yarn having a fineness of 275 dtex, 72 filaments, and an elongation of 158%. The highly oriented undrawn yarn was fed from a feed roller using a pin false twisting machine (TH312, manufactured by Aiki Seisakusho) and first subjected to low-ratio drawing of 1.5 times at a hot pin temperature of 80°C at a processing speed of 100 m/min, then false twisted at a draw ratio of 1.1 times, a heater temperature of 190°C, and a false twist coefficient of 33,000, and then interlaced at an entanglement pressure of 0.15 MPa to obtain a textured yarn having a fineness of 167 dtex, a crimp rate of 41%, a boiling water shrinkage rate of 4.5%, a single yarn length difference of 12%, an entanglement number of 58/m, and a number of recesses of 8.

The yarns were then used as the warp and weft to weave a plain weave fabric on an air jet loom. The resulting woven fabric was then subjected to continuous open-weave scouring at 98°C, flow relaxation at 120°C, intermediate setting at 180°C, and dyed navy blue at 130°C using a disperse dye, and then finishing setting at 160°C to produce a product with a processed density (warp: 110 threads/2.54 cm, weft: 90 threads/2.54 cm).

The resulting fabric had a natural heathered look similar to that of natural wool, was very fluffy, and had a very calm, glossy appearance. It also had excellent snag resistance even after repeated washing, making it suitable for use as a worsted outer garment.

<Comparative Example 1>
Polyethylene terephthalate having a round cross section and a titanium oxide content of 0.7% by mass was spun at a spinning speed of 3,2000 (m/min) to obtain a highly oriented undrawn yarn having a fineness of 265 dtex, 48 filaments, and an elongation of 142%. The highly oriented undrawn yarn was then fed from a feed roller using a friction false twisting machine (ATF12, manufactured by TMT Machinery) and first subjected to low-ratio drawing of 1.45 times at a hot pin temperature of 75°C at a processing speed of 400 m/min, followed by false twisting at a draw ratio of 1.1 times, a heater temperature of 200°C, and a false twist coefficient of 31,000, and then subjected to interlacing processing at an entanglement pressure of 0.2 MPa to obtain a processed yarn having a fineness of 167 dtex, a crimp rate of 33%, a boiling water shrinkage rate of 7.5%, a single yarn length difference of 3%, an entanglement number of 90/m, and a number of recesses of 1.

The yarn was then twisted at 300T/M and used as the warp and weft to create a plain weave fabric on an air jet loom. The resulting woven fabric was then subjected to continuous open-weave scouring at 98°C, flow relaxation at 120°C, intermediate setting at 180°C, and dyed navy blue at 130°C using a disperse dye, and then finishing setting at 160°C to create a product with a processed density (warp: 110 threads/2.54 cm, weft: 90 threads/2.54 cm).

The resulting fabric had an artificial heathered look, lacked volume, and had an overall shiny sheen characteristic of synthetic fibers.

<Comparative Example 2>
Polyethylene terephthalate with a titanium oxide content of 0.7% by mass and an eight-lobe cross section was spun at a spinning speed of 3,2000 (m/min) to obtain a highly oriented undrawn yarn with a fineness of 265 dtex, 48 filaments, and an elongation of 143%. The highly oriented undrawn yarn was fed from a feed roller using a friction false twisting machine (ATF12: manufactured by TMT Machinery) and false twisted at a processing speed of 400 m/min, a draw ratio of 1.6 times, a heater temperature of 200° C., and a false twist coefficient of 31,000. Thereafter, interlacing was performed at an interlacing pressure of 0.15 MPa to obtain a processed yarn with a fineness of 167 dtex, a crimp rate of 43%, a boiling water shrinkage rate of 6.1%, a single yarn length difference of 2%, an interlacing number of 65/m, and a number of recesses of 8.

The yarn was then twisted at 300T/M and used as the warp and weft to create a plain weave fabric on an air jet loom. The resulting woven fabric was then subjected to continuous open-weave scouring at 98°C, flow relaxation at 120°C, intermediate setting at 180°C, and dyed navy blue at 130°C using a disperse dye, and then finishing setting at 160°C to create a product with a processed density (warp: 110 threads/2.54 cm, weft: 90 threads/2.54 cm).

The resulting fabric had a subdued luster, but lacked volume and a flat surface with no grain.

<Comparative Example 3>
Polyethylene terephthalate having a titanium oxide content of 0.7% by mass was spun at a spinning speed of 3,2000 (m/min) using a spinneret having 24 four-lobe holes and 24 eight-lobe holes arranged, to obtain a highly oriented undrawn yarn having a total fineness of 264 dtex, 48 filaments, and an elongation of 141%. The highly oriented undrawn yarn was then fed from a feed roller using a friction false twisting machine (ATF12, manufactured by TMT Machinery) and first subjected to a low-ratio drawing of 1.38 times at a hot pin temperature of 74°C at a processing speed of 400 m/min, followed by false twisting at a draw ratio of 1.15 times, a heater temperature of 130°C, and a false twist coefficient of 31,000, and then interlacing at an entanglement pressure of 0.35 MPa to obtain a composite textured yarn having a fineness of 167 dtex, a crimp rate of 23%, a boiling water shrinkage rate of 7.7%, a single yarn length difference of 16%, an entanglement number of 155/m, and a number of recesses of 4 and 8.

The yarns were then used as the warp and weft to weave a plain weave fabric on an air jet loom. The resulting woven fabric was then subjected to continuous open-weave scouring at 98°C, flow relaxation at 120°C, intermediate setting at 180°C, and dyed navy blue at 130°C using a disperse dye, and then finishing setting at 160°C to produce a product with a processed density (warp: 110 threads/2.54 cm, weft: 90 threads/2.54 cm).

The resulting fabric had the same natural heathered look as natural wool and a subdued glossy appearance, but it lacked volume and fluffiness, and after repeated washing some of the single threads came loose, giving it a grade 2 snag resistance.

<Comparative Example 4>
Polyethylene terephthalate having an eight-lobe cross section and a titanium oxide content of 0.7% by mass was spun at a spinning speed of 3,2000 (m/min) to obtain a highly oriented undrawn yarn having a fineness of 140 dtex, 36 filaments and an elongation of 140%. Then, two of the highly oriented undrawn yarns were prepared, and each was fed by a separate feed roller. Using a friction false twisting machine (ATF12: manufactured by TMT Machinery), one of the yarns was drawn at a low magnification of 1.5 times at a hot pin of 75°C and the other yarn was drawn at a hot pin of 1.7 times at a processing speed of 400 m/min. Thereafter, the two yarns were joined together and interlaced at an entanglement pressure of 0.25 MPa. Thereafter, false twisting was performed at a draw ratio of 1.05 times, a heater temperature of 2100°C, and a false twist coefficient of 31,000 to obtain a composite textured yarn having a fineness of 170 dtex, a crimp rate of 8%, a boiling water shrinkage rate of 5.3%, a single yarn length difference of 23%, an entanglement number of 97 pieces/m, and a number of recesses of 8.

The yarn was then twisted at 1000T/M and used as the warp and weft to create a plain weave fabric on an air jet loom. The resulting woven fabric was then subjected to continuous open-weave scouring at 98°C, flow relaxation at 120°C, intermediate setting at 180°C, and dyed navy blue at 130°C using a disperse dye, and then finishing setting at 160°C to create a product with a processed density (warp: 110 threads/2.54 cm, weft: 90 threads/2.54 cm).

The resulting fabric had a natural heathered look, a subdued glossy appearance, and a large sense of volume, but after repeated washing, the single threads were noticeably sticking out, and the snag resistance was grade 1.

<Comparative Example 5>
Polyethylene terephthalate having a titanium oxide content of 0.7% by mass and polytrimethylene terephthalate having a titanium oxide content of 0.1% by mass were bimetallicly combined in a side-by-side type in a mass ratio of 50:50 and spun at a spinning speed of 3,1000 (m/min) to obtain a highly oriented undrawn yarn having a fineness of 268 dtex, 48 filaments and an elongation of 165%. The highly oriented undrawn yarn was then fed from a feed roller using a friction false twisting machine (ATF12, manufactured by TMT Machinery) and first subjected to a low-ratio drawing of 1.5 times at a hot pin temperature of 75°C at a processing speed of 400 m/min, followed by false twisting at a draw ratio of 1.1 times, a heater temperature of 200°C, and a false twist coefficient of 32,000, and then interlacing at an entanglement pressure of 0.2 MPa to obtain a textured yarn having a fineness of 167 dtex, a crimp rate of 48%, a boiling water shrinkage rate of 7.5%, a single yarn length difference of 3%, an entanglement number of 87/m, and a number of recesses of 2.

The yarn was then twisted at 300T/M and used as the warp and weft to create a plain weave fabric on an air jet loom. The resulting woven fabric was then subjected to continuous open-weave scouring at 98°C, flow relaxation at 120°C, intermediate setting at 180°C, and dyed navy blue at 130°C using a disperse dye, and finished setting at 160°C to create a product with a processed density (warp: 110 threads/2.54 cm, weft: 90 threads/2.54 cm).

The resulting fabric had a natural heathered look and a very fluffy feel, but also had a shiny luster characteristic of synthetic fibers in some places. Furthermore, after repeated washing, single threads came loose, and the snag resistance was grade 2.

The false-twisted yarn and woven/knitted fabrics obtained by the present invention are widely used as outerwear for casual, formal and sportswear. They are particularly suitable for use in women's Western-style suits, blazers, coats, skirts and pants, as well as men's outerwear, bottoms and jackets.

S1: Point of contact S2 between the line T1 and the fiber cross-sectional profile; Point of contact T1 between the line T1 and the fiber cross-sectional profile; Line U tangent to the fiber cross-sectional profile at S1 and S2; Recess between the points of contact S1 and S2

Claims (6)

The polyester false-twisted yarn has thickness unevenness in the length direction, is made of a homopolymer, has an inorganic fine particle content of 0.3 to 3.0 mass%, a boiling water shrinkage rate of 4 to 9%, a crimp rate of 26 to 45% , has 6 to 10 recesses in a single yarn cross section , and has a local single yarn length difference of 5 to 20% for one type of yarn . 2. The polyester false twist yarn of claim 1, wherein said homopolymer is polyethylene terephthalate. 3. The polyester false twist yarn according to claim 1 , wherein there is a phase difference in the thick/thin unevenness between single yarns. 4. The polyester false twist yarn according to claim 1 , wherein the degree of entanglement is 50 to 150 pcs/m. A woven or knitted fabric using the false twist yarn according to any one of claims 1 to 4 . The woven or knitted fabric according to claim 5 , characterized in that the result of a snag test according to JIS L 1058: 2011 7.2 after 20 washes is grade 3 or higher.