JPS59216918A - Twisted polyester fiber and its manufacture - Google Patents

Abstract

PURPOSE:To manufacture a polyester fiber twisted around the fiber axis, by carrying out the orienting crystallization spinning of a polyester, subjecting the obtained polyester fiber having latent crimping property to the relaxed heat- treatment to temporarily actualize the latent crimp, and then carrying out the heat-treatment under tension. CONSTITUTION:A polyester fiber having latent crimping property and obtained by the orienting crystallization spinning is subjected to the single stage or multi- stage drawing and then to the relaxed heat-treatment to temporarily actualize the latent crimp. After the relaxed heat-treatment, the fiber is heat-treated under tension e.g. at 180-250 deg.C and a stretch ratio of 1-1.05 to extend the crimp developed by the above relaxed heat-treatment and convert the crimp to the twist of the fiber. The objective polyester fiber twisted around the fiber axis and having an apparent crystal size of >=50Angstrom at the 010 plane of the fiber, and the ratio of the apparent crystal size at the 010 plane to the one at the 100 plane of >=1.10, is manufactued by this process.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel twisted polyester fiber and a method for producing the same. This invention relates to polyester fibers for textiles and methods for producing the same.

Conventionally, M-woven fabrics using natural fibers have less pilling (pilling), but knitted fabrics using synthetic fibers are known to have the disadvantage of significantly pilling compared to this. In order to solve this problem, many proposals have been made since Japanese Patent Publication No. 35-8562 to use a low-viscosity polymer from the viewpoint of reducing the strength and imparting anti-pilling properties to polyester fibers. However, these methods result in lower tenacity due to lower viscosity, which significantly reduces operability in the spinning and post-processing stages, increases costs, and lowers other qualities in order to obtain pill resistance. There are problems such as how to For this reason, a method of imparting anti-pilling properties through drug treatment etc. in the post-processing stage was developed.
Although many methods have been proposed since Publication No. 844, post-processing methods result in high costs due to low productivity, problems with post-processing of used chemicals (waste liquid treatment), etc. For this reason, methods of lowering the nodule strength and increasing the strength have been proposed in JP-A-49-26516 and JP-B-51-43089, but these methods are similar to the above-mentioned method. The problem of operability in the spinning and drawing stage due to the use of low-viscosity polymers has not been fully resolved, and because the knot strength is low, the only improvement is the card passability in the spinning stage, and the productivity of all the spinning stages can be improved. We haven't reached that point yet. Since the cause of this is low viscosity, methods for producing anti-build fibers using high viscosity polymers have been published in Japanese Patent Publication No. 47-9854 and Japanese Patent Application Laid-open No. 52-14.
Although it has been proposed in Japanese Patent Application No. 8221, etc., at present, even methods using these high viscosity polymers have not provided sufficient anti-pilling properties superior to cotton.

The inventors of the present invention have conducted intensive research to solve the above problems and obtain anti-pill polyester fibers that are inexpensive and have good post-processability. The present invention was achieved based on the discovery that the anti-pilling properties can be significantly improved by binding to these compounds.

That is, the fiber of the present invention has an apparent crystal size of the 010 plane (A Csu.) of at least so Ratio (A CBar
The polyester fiber is characterized in that e/A CS +□) is 1.10 or more and has a twist in the fiber axis.

The apparent crystal size of 100 planes of the fiber according to the present invention and o
This is the crystal size calculated using the following 5herrsr formula from the half value of the intensity of the io plane. For details, see ``RXS Crystallography'' published by Maruzen Co., Ltd., supervised by Isamu Nita0 AC8 = (nλ) / ((f The fiber of the present invention has an apparent crystal size in the 010 plane of at least soX, preferably at least ssX, and further has ACL re /
A C81m is 1.10 or more, preferably 1.20 or more, and the a-off axis has twist. AC8 is a fiber with twist in the fiber axis. Even if is 50X or more, A C
Sel. / A C8re. If it is less than 1.10, it does not exhibit sufficient vinyl resistance. m#A fiber with twist in the a axis AC8,. /A C8,,. Even if the ACC10 is less than 50 A, even if the ACC10 is less than 50 A, sufficient anti-building properties are not exhibited. Further, even if all of the above-mentioned crystal sizes meet the requirements for the fiber of the present invention, a fiber without twist in the alim will not exhibit sufficient anti-build properties. Note that fibers with an apparent crystal size of 100 planes of 35X or more, preferably 40X or more exhibit even better anti-build properties.

The fiber of the present invention has significantly improved anti-pilling properties when compared with conventionally known anti-pilling polyester fibers, and the improvement is that the anti-pilling properties are superior to cotton, and the pilling test described below It exhibits the highest level of excellent anti-pilling performance in the industry, and is rated as having virtually no pill formation. The reason for this is not yet clear, but according to the inventors' speculation, the fibers of the present invention have a crystalline size that is smaller than that of conventional polyester fibers for clothing from the viewpoint of crystal structure. Because it is large and has a crystal structure that grows in the b-axis direction, it is strong against tension in the c-axis direction, but it is weak against tension that is accompanied by twisting, thus promoting the falling off of the generated pill and twisting the single fibers. Therefore, when the fibers are spun into yarn, the frictional resistance due to the twist of the single fibers increases, making it difficult for the single fibers to fall out, which has the special effect of suppressing the growth of pills.
It is thought that these effects result in excellent antiviral properties with virtually no pill formation.

The twist in the present invention is 17 per denier per single fiber.
This refers to torsion in which the fiber axis rotates 60 degrees or more under a load of 309, and the twist direction may be either a right-handed thread direction, a left-handed thread direction, or a mixture of both. The twist pitch referred to in the invention is the average distance between the twisted portions 1a of the twist described above when the fiber axis rotates for more than 60 summers with a load of 1730 t per denier applied to the single fiber 1 in Fig. 1. Yes, using a casetometer, fiber length 1c for each 20 single fibers.
The above twisted portion per m3. The number N of a is measured and determined by the following formula. The smaller the twist pitch mentioned above, the harder it is for single fibers to come off, so you can make it as small as you like, but
Preferably, the number of cods is 5 or less, and more preferably 2 or less. When the twist pitch exceeds IOn, the effect of preventing single fibers from being pulled out becomes smaller.

Figure 1 is an enlarged side view of the polyester fiber of the present invention, Figure 2 is an enlarged side view of the polyester fiber of the present invention;
The figure shows the fiber of the present invention obtained in Example 1, polyester #! with a twist pitch of about 0.6! 1i fiber is shown.

The polyester component forming the polyester fiber of the present invention has ethylene terephthalate units as its main constituent unit, and is usually a copolyester or homopolyester containing 85 mol% or more of ethylene terephthalate units, or a polyester mixture thereof. Copolymerization components other than terephthalic acid and ethylene glycol include isophthalic acid, 2,6-naphthalene dicarboxylic acid,
Examples include adipic acid, sebacic acid, chelic acid, diethylene glycol, propylene glycol, cyclohexane dimetatool, p-oxybenzoic acid, 3,5-di(carbomethoxy)benzenesulfonic acid metal salts, and derivatives thereof. It is not limited to the specific examples.

The cross-sectional shape of the fiber of the present invention is not particularly limited, but in particular, those having a U-shape, ■-shape, or a shape in which projections are added thereto are likely to be twisted in a specific direction because they have openings in their cross-sectional outline. Also, yarns having these shapes are particularly preferred because oriented crystallization in the spinning step proceeds at a lower spinning speed than yarns with a circular cross section. Furthermore, if a yarn with a flat cross-section is twisted and made into a spun yarn, the single fibers will not easily come off, which is preferable. The characteristic of the fiber of the present invention is that it exhibits anti-build properties similar to or better than cotton. However, it also has characteristics such as superior tensile strength and knot strength compared to conventionally known anti-build fibers.

Although the knot strength of the fibers of the present invention is not particularly limited, the preferred range is 3 to 4 f/d.

The fibers of the present invention are produced by controlling the molecular arrangement of the fibers by combining ultrahigh-speed spinning technology and high-temperature, low-elongation drawing technology.

The method for manufacturing the fiber of the present invention will be explained below.

In the method for producing fibers of the present invention, polyester fibers that have been subjected to oriented crystallization spinning and have been given latent crimp ability are subjected to a relaxing heat treatment to make the latent crimp manifest, and then the fibers are subjected to a tension heat treatment. This is a method for producing homoester fibers having a twist in the fiber axis, which is characterized by converting crimps that become apparent by stretching and converting them into twists. Oriented crystallized yarn is obtained by extrusion in a machine and by ultra-high speed spinning of polyethylene terephthalate of 0.0 to 0.8, preferably 0.5 to 0.8. How to determine whether oriented crystallized yarn has been obtained (b) A method of determining whether the density of the yarn has increased rapidly by measuring the density of the yarn; (c) Shrinkage of the yarn under dry heat at 160°C There are methods such as measuring the SHD rate (hereinafter abbreviated as SHD) and determining whether the SHD is 10% or less, but the simplest method is the method using SHD (c) above, which is
If it is 0% or less, it may be determined that oriented crystallized threads have been obtained. Also, in this spinning step, it is preferable to impart latent crimp ability to the fibers in order to impart twist. As a method for imparting latent crimp ability, any one of the asymmetric cooling method, composite spinning method, and single-sided heating method is used. When using the asymmetric cooling method, cooling is performed from one side of the spun yarn directly under the nozzle. The fibers are asymmetrically cooled by blowing an air current to impart cross-sectional anisotropy in the cross-sectional direction of the fibers while being taken off. In this case, the spinning speed is set so that the resulting yarn has a 5) ID of 5 to 10%. is preferable. If the spinning speed is too high, cross-sectional anisotropy may disappear, so care must be taken. On the other hand, when using a composite spinning method that utilizes a viscosity difference (for example, side-pie-side type or eccentric sheath-core type), it is preferable to set the spinning speed so that the SHD is 4 to 10%.

On the other hand, if latent crimp ability is not imparted at the spinning stage, latent crimp ability is imparted by subjecting the yarn before or after drawing to one-sided heat treatment. In this case, the spinning speed during spinning is not limited except for the condition that the SHD of the undrawn yarn is 10% or less, so a spinning speed of 10,000 m/min or more can be adopted and productivity can be increased. . Single-sided heating may be performed using a known method such as a hot plate, a heating roller, or light energy irradiation.

The main purpose of ultra-high speed spinning in producing the fibers of the present invention is to
The purpose is to develop oriented crystallization during the spinning and drawing steps, and to form crystal nuclei for promoting crystallization during the subsequent drawing heat treatment. From this point of view, the relationship between spinning speed and oriented crystallization is important. For example, in the case of polyethylene terephthalate (intrinsic viscosity 0°61), the spinning speed at which oriented crystallization is achieved with round cross-section yarn is 4 soom/min or more, but with irregular It has been found that oriented crystallization occurs at a speed of 4000 m/min or more in the case of yarns having a cross-section (for example, a ramie-shaped cross-section).

The oriented crystallized yarn is then drawn in one or multiple stages (preferably in two stages).
Stretched by step stretching). The drawing conditions are such that the SHD of the drawn yarn is 10% or less at a temperature at which the latent crimp ability is not lost, and
It is preferable to set the conditions such that the degree of elongation (hereinafter abbreviated as DE) is 10% or less.

For example, in the case of one-stage stretching, the stretching temperature is 60 to 160°C, preferably 70 to 130°C, and the stretching ratio is 1.3 to 1.
It is preferable to set it to 4. In the case of two-stage stretching, the stretching conditions for the first stage are the same as those for the first stage stretching (however, it is recommended that the stretching ratio be 1.2 to 1.3 times, and the stretching conditions for the second stage It is preferable to carry out the stretching at a temperature 10 DEG C. or more higher than the first-stage stretching temperature so that the total stretching ratio is 1.3 to 1.5 times.

Then, latent crimp is brought to light by relaxing heat treatment after stretching. Relaxation rate is 10% or more, preferably 15%
The above shall apply. SHD of relaxing heat treatment system is less than 2%,
It is preferable to set the conditions such that DE is 20% or less. The relaxation heat treatment temperature is 150°C or higher and 200°C or lower, preferably 180°C or higher and 200°C or lower. If the relaxation heat treatment temperature is too high, the crystal size will grow from 100 faces to AC8ue/AC8. . is not preferable because it becomes small.

Next, by performing a tension heat treatment after a lyratus heat treatment,
Decrimping, which stretches out the crimps developed by the relaxing heat treatment, converts the crimps into twists and completes the crystal structure of the fiber of the present invention. For this reason, setting the tension heat treatment conditions is important. Heat treatment temperature is 180°C or higher and 250°C or lower, good*L, 1f220'c or higher and 240'C
Hereinafter, the tension ratio is the magnification that completes the crystal structure of the fiber of the present invention without destroying the structure formed during relaxing heat treatment.
Preferably it is 1 to 1.05 times. If the tension I ratio is too high, the structure is destroyed and elastic crimp occurs again after the tension heat treatment, resulting in a three-dimensional crimp yarn, which is not preferable. Also, if the temperature is too low and the heat treatment is essentially relaxing, ACSe+. /Ac
S. . is not preferable because it becomes small.

As shown in Figure 2, the fibers obtained in this way have a twist, a large crystal size, and Acs, 1°/AC8,
. . It also has a large characteristic of 1.10 or more.

In carrying out the present invention, twisting may be applied continuously or discontinuously after stretching. In order to impart twist, if latent crimp ability is not imparted at the spinning stage, latent crimp ability is imparted to the yarn by heating treatment on one side of the yarn after spinning, before stretching, or after stretching. In this case, torsion is imparted in the same way as in the case where latent crimp ability is imparted at the spinning stage, and after the latent crimp is made manifest, twist is imparted by decrimping.

When using the fiber obtained by the above method as a staple, it is preferable to preheat the fiber to 120 DEG C. or higher, since mechanical winding with a push-in crimper will be low and entanglement will be reduced during spinning.

The stapled fibers obtained by the above method have spinnability,
Weavability! The woven and knitted fabric has excellent anti-pilling properties as well as excellent dyeability compared to conventionally known anti-pilling polyester fibers using low viscosity polymers. When the fiber has an irregular cross section, it also has a cotton-like texture.

When the fiber of the present invention is used as a filament, it is used by winding it up without cutting it. It has also been found that filament-like knitted fabrics have good anti-snag properties.

The single yarn denier of the fiber of the present invention is not particularly limited, but it is about 0.1 denier for suede, 0.5 to 2 denier for cotton-spun type, and 2 denier for wool blend.
It is preferable to appropriately select from denier to 4 denier, and for carpets from 3 denier to 30 denier depending on the use.

The fiber of the present invention can of course be used as a single material woven or knitted fabric! Excellent pill resistance for blended yarns and processed yarns in combination with different types of fibers other than IaI11, as well as mixed fibers, mixed knitted fabrics, non-woven fabrics, heavy fabrics, multi-layer m-knitted fabrics, etc. with yarns made of different types of fibers or 14 types of fibers. Demonstrates sexual effects.

The fibers of the present invention can be used for dress shirts, casual shirts, women's blouses, women's skirts, underwear, slacks, men's formal wear, formal wear, knitwear, sportswear, coats, general outwear, babywear, General children's clothing, men's suits,
Jackets, blouson, 22 home general items, kimono, household items (nibs, table cloths, gloves, hats, etc.), bedding mats or night clothes (futons, sheets, duvet covers, pajamas, etc.)
, inch rear goods, carpets and other industrial materials.

The fibers of the present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples. For the measurement of the crystal size of the fibers, In this measurement, α was added to X11i1Cu−.
Using the line (λ-1, 5418X), the correction coefficient n is 0.9
, the correction angle α was 6.98×10 (rad).

Example! Polyethylene terephthalate with an intrinsic viscosity of 0.63 obtained by polycondensation from terephthalic acid and ethylene glycol by a conventional method was spun at a spinning temperature of 29 G'C, with a vM slit hole slit width of 0.05 cm, and a cross-sectional area of a single hole of 0. .3w+jil
From a spinneret with a nozzle hole 't & 24 holes (equivalent to a round hole), each spun ffl yarn was spun at a discharge rate of 0.96 f1 per single hole using cooling air at room temperature at a wind speed of 0.9 m/sec. Spray from one side of the yarn to cool it asymmetrically for 4oooom.
/ minute] took it. 81 (D was 6%) of the yarn was then stretched to 1 at a stretching ratio of 1.3 times at a heating roller temperature of 80°C and a heating plate temperature of 120'C.
Stage stretching, then heating plate temperature 15 (1.0 at l)
A second stage of stretching was performed at a stretching ratio of 5 times, and subsequently,
Heat treatment was performed in a dry heat hot air zone at 160'C at a relaxation rate of 20% to develop spiral curling, and then 2
The spiral crimp was stretched and turned into a twist by stretching by a factor of 1.05 using a heating plate at 30°C. The single yarn denier of this filament is! , 7 de.

Next, this filament is drawn to 5oooo denier using a push-in crimper at a preheating temperature of 180°C to wrap the net at ¥12%.
After mechanical crimping with a number of crimping of 15/25+m, the material was cut into 38 pieces. The obtained staple was made into a spun yarn having a count of 308 and a twist coefficient of 3.2 by a conventional method. Next, from this spun yarn, an inter-four-way rope with a basis weight of 200f/lIs was created, and 177 buildings (Neugen HC2f/L) were made.
IC was applied to a knitted fabric treated in a 0.5 f/l aqueous solution of NalCo at 70°C for 20 minutes and then washed at 50'C for 10 minutes.
Anti-building properties were evaluated using an I pilling tester. Table 1 shows the properties of the fibers and the results of anti-pilling evaluation.

Note that FIG. 2 shows a 200x magnification microscope lens showing the side surface of the polyester fiber of the present invention obtained in Example 1.

Here, as a comparative example, an inter-0 ivy knitted fabric with the same basis weight was made using the same yarn of 100% cotton and the same twist coefficient as in the above example, and scouring (H* Ot4 ml/L 1Na
OH1t/Ls Artrin A P 80 p 1
After boiling f/Z% Hinogu-NO, 35f/ in an aqueous solution for 30 minutes and washing with water at 50°C for 10 minutes, anti-building properties were evaluated in the same manner as in the above examples. The result is the first
Shown in the table.

From the comparison results, it was found that the fibers of the present invention exhibit superior anti-pilling properties compared to cotton fibers, have virtually no pilling, and have a soft and crisp texture similar to that of cotton. Ta.

Example 2 Intrinsic viscosities obtained by polycondensation of terephthalic acid and ethylene glycol by a conventional method (4 constant at 30°C in a mixed solvent of phenol/tetrachloroethane = 6/4) o, 6s and 0.
57 polyethylene terephthalate at spinning temperatures of 290°C and 284°C, respectively) (medium 0.02111K)
From a spinneret having a slit hole with a slit length of 0.08 mm, both components are discharged side by side in the longitudinal direction of the slit, and each component is discharged at a discharge rate of 0 to 5 f/min per single hole. It was taken out at a speed of 5000 m/min while being cooled with room temperature cooling air at a rate of 0.3 m/sec. The SHD of the yarn was 6%. Next, this yarn is heated at a temperature of 80°C on the first stage heating ruler and 180°C on the heating plate.
．． One stage of stretching was carried out at a stretching ratio of 4 times, then a second stage of stretching was carried out at a stretching ratio of 1.1 times at a heating roller temperature of 120°C and a heating roller temperature of 200'C, followed by dry heat at 185°C. Heat treatment is performed in the hot air zone at a relaxation rate of 25%,
Next, a staple was obtained in the same manner as in Example 1, except that it was stretched 1.05 times using a 250 t heating plate and decrimped, and the anti-pilling property was evaluated as a spun yarn and a knitted fabric. The results are shown in Table 1.

The fiber of the present invention showed excellent anti-build properties as in Example 1.

Example 3 First-stage stretching heating plate temperature 180°C, stretching ratio 1.
The anti-build properties of polyester staples produced under the same conditions as in Example 1 were evaluated in the same manner as in Example 1, except that the heating plate temperature in the second stage of stretching was 35 times and the heating plate temperature was 200 degrees Celsius, and the stretching ratio was 1.06 times. did. The results are shown in Table 1. Since the stretching conditions were such that the latent crimp ability was slightly lost, the torsion pitch was larger than that of the fiber shown in Example 1, and the anti-pilling property was also higher than that of the fiber of Example 1, although the series was slightly lower than that of the fiber shown in Example 1. It showed alternative anti-pilling properties.

Comparative Example 1 A staple was obtained in the same manner as in Example 1 except that the stretching ratio after relaxing heat setting was 1.3, and its anti-build property was evaluated. Table 1 shows the evaluation results of staple properties and anti-build properties. In the case of this comparative example, the structure was destroyed because the stretching ratio after relaxing heat setting was increased, and after stretching, elastic crimp occurred and the twist disappeared. Since breakage occurs and three-dimensional crimping remains, the spinnability deteriorates, and only a product with blurred threads, which is characteristic of three-dimensional crimping systems, is obtained.

Comparative Example 2 A polyester yarn spun in the same manner as in Example 1 was spun at a heating roller temperature of 80°C and a heating plate temperature of 120°C.
The staple was stretched at a stretching ratio of 36 times, then subjected to relaxation heat treatment at 155° C. for 3 minutes, and then cut into 38-mm pieces. The resulting staple was evaluated for leech resistance in the same manner as in Example 1. Table 1 shows the evaluation results of staple properties and curl resistance. In comparison with the fiber of the present invention, this comparative example has no twist, has a three-dimensional winding, and has an AC8,... /AC8,. . is smaller than 1.10, which indicates poor spinnability and poor pill resistance.

Comparative Example 3 Polyethylene terephthalate with an intrinsic viscosity of 0.46 was lowered. ), the yarn taken at 400 Q m Z minutes was drawn in one stage at a stretching ratio of 1.2 times with a heating sealer temperature of 80°C and a heating plate temperature of 180°C, and then a heating plate temperature of 18.0°C. A second stage of drawing was carried out at a drawing ratio of 1.03 times at ℃, and the drawn yarn was 500 mm.

It was drawn to a denier, mechanically crimped using a push-in crimper at a preheating temperature of 180°C, and then cut into 38 ml pieces.

The anti-pilling properties of the obtained staples were evaluated in the same manner as in Example 1. Table 1 shows the evaluation results of staple properties and anti-pilling properties. As shown in this comparative example, it can be seen that the conventional method of imparting anti-pilling properties using a low viscosity polymer results in poor thread-spinning properties and does not provide good results in terms of anti-pilling properties.

Comparative Example 4 Discharge amount per single hole 0.5t/molecule, cooling air velocity 2. The Om stretching temperature was 80°C for the roller and 130°C for the heating plate. The drawn yarn was heated at 135°C with a relaxation rate of 25%.
Relaxation heat treatment for 2201111:0°98
It was dry heat treated and decrimped at twice the temperature, mechanically crimped at a preheating temperature of 200°C, and then cut into 38II 1m. Table 1 shows the properties of the obtained staple and the anti-build properties evaluated in the same manner as in Example 1. This comparative example, which had a small ACS, had poor anti-building properties.

Furthermore, since the knot strength was slightly lower, the spinnability was also affected. When the draw ratio during decrimping was increased, single filament breakage occurred, so the draw ratio during decrimping was set to 0°98 times.

Comparative Example 5 Cooling air velocity 0.2 m/sec f taking speed 35'00 m/sec
A polyester undrawn yarn was obtained. This undrawn yarn is heated at both the first and second stage rollers at a temperature of 80°C and a heating plate temperature of 130°C.
After stretching at a total stretch ratio of 1.35 times at a temperature of 1.35 times, the tow was subjected to a relaxation heat treatment for 5 minutes in a dry heat at 155 degrees Celsius, and then the tow was decrimped in a dry heat treatment at 1.03 times for 2 minutes at 220 degrees Celsius, and then further stretched to a fixed length. It was preheated at 220°C and cut to 38 tm after being mechanically crimped. Table 1 shows the properties of the obtained staple and the anti-build properties evaluated in the same manner as in Example 1. Although the crystal size was large due to sufficient heat treatment and twist was imparted, the pill resistance was not good, probably because the ACS-+a/ACS+n ratio was small. Furthermore, the mechanical properties were not favorable and the operability was also not good.

Comparative Example 6 A polyester staple was produced in the same manner as in Example 1, except that the undrawn yarn obtained in the same manner as Comparative Example S was stretched at a stretching ratio of 1.35 times in the first stage and 1.01 times in the second stage. Obtained. The anti-build property of the obtained staple was evaluated in the same manner as in Example 1. Table 1 shows the evaluation results of staple properties and anti-build properties.

Although this fiber had twist, the crystallization was insufficient because the nest-drawn yarn was not oriented and crystallized, and the crystal size was small, so the anti-pilling property was not favorable.

Margin below

[Brief explanation of the drawing]

FIG. 1 is an enlarged side view of the fiber of the present invention, and FIG. 2 is a side micrograph at 200 times magnification of the polyester fiber obtained in Example 1 of the present invention. Patent applicant: Toyobo Co., Ltd.

Claims (1)

[Claims] 1. Apparent crystal size of 010 plane of fiber (ACs-n
) is 50X or more, the apparent crystal size of the oio plane (AC
8,,, ) and the apparent crystal size of 100 planes (AC8s
ee) ratio (A Cs*+e /Ac 81°,) is 1
．． 10 or more and having a twist in the fiber axis. 2. Apparent crystal size of 10+0 plane of fiber (AC80
0,) is 35'A or more, the polyester fiber according to claim 1. 3. The polyester fiber according to any one of claims 1 to 2, wherein the twist pitch of the fiber is 5 sm or less. 4.Claims 1 to 3, wherein the cross-sectional shape of the fiber is a U-shape or a V-shape with protrusions added thereto.
The polyester fiber according to any one of item d. 5. Polyester fibers that have been subjected to oriented crystallization spinning and have been given latent crimp ability are subjected to a relaxation heat treatment to once reveal the latent crimp; A method for producing a polyester fiber having a twist in the fiber axis, characterized by stretching the curl and converting it into twist 6. The polyester fiber according to claim 5, in which the latent crimp ability is imparted by an asymmetric cooling method. manufacturing method. 7. The method for producing polyester fibers according to claim 5, wherein the latent crimp ability is imparted by a composite spinning method. 8. The method for producing polyester fibers according to claim 5, in which the latent crimp ability is imparted by heat treatment on one side.