JP2024035461A - Polyester short fiber having excellent antipilling property - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester short fiber which is low in cost and has excellent antipilling properties, a woven or knitted fabric which comprises the same, and methods for producing them.

SOLUTION: There is provided a polyester short fiber having one character grooves not parallel to a fiber axis direction in a fiber surface, and the grooves are present at a frequency of 300 or more to 3,000 pieces or less per mm of the fiber length. The polyester short fiber is composed of aromatic polyester which has repeating units consisting mainly of ethylene terephthalate and has an inherent viscosity [η] of 0.45 or more to 0.90 cm³/g or less. It is preferable that its tensile strength is 0.35 or more to 0.65 cN/tex or less and an impulse shown by a product between the square roots of the tensile strength and its elongation percentage is 1.20 or more to 2.40 or less and its knot strength is 0.20 or more to 0.55 cN/tex or less. A woven or knitted fabric comprising this polyethylene short fiber by 50 t.% or more has high antipilling properties.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention is made into woven or knitted fabrics as polyester spun yarn, polyester blended yarn, polyester mixed long/short composite spun yarn, etc., or polyester short fiber nonwoven fabrics typified by needle punching, stitch bonding, thermal bonding, spunlace, and air laid. The present invention relates to short polyester fibers that can exhibit excellent anti-pilling properties.

Polyester fibers have been widely used as general-purpose thermoplastic synthetic fibers. Polyester fibers, especially polyethylene terephthalate fibers, are relatively inexpensive and have excellent physical properties such as strength and elongation, as well as heat resistance, chemical resistance, and abrasion resistance, and are used for general clothing applications such as clothing, as well as household materials such as curtains and carpets. It is a textile material that is widely used as an industrial material, and its production will continue to increase worldwide. However, when polyester fibers are used in knitted fabrics or loosely textured fabrics, they have the disadvantage that pilling tends to occur, which significantly impairs the appearance quality of the product.

In order to improve this drawback, for example, Patent Document 1 proposes a composite spun yarn having a core-sheath structure in which low-strength short fibers are arranged on the sheath side and high-strength short fibers are arranged on the core side. In this proposal, practical strength is provided by high-strength short fibers on the core side, and low-strength short fibers with weak knot strength are placed on the sheath side, which can suppress pill growth. Abrasion loss occurs in which strong short fibers are selectively and strongly removed, causing a problem in which the fabric becomes partially thin due to repeated wear.

Moreover, Patent Document 2 proposes a method of using air-spun yarn with less fuzz on the surface of a knitted fabric. In this proposal, the air spinning machine used has a hollow air nozzle, and the air flow inside the air nozzle forms a spun yarn in the form of bundled short fibers around untwisted spun yarn. The number of fuzz per unit length in the longitudinal direction is substantially smaller than that of ring-spun yarn, and the length of exposed fuzz is also shorter, resulting in excellent anti-pilling properties. However, air-spun yarn generally has less luster than ring-spun yarn, has a harder texture, and has poor drape properties, so it is difficult to use it in clothing fields that require aesthetics, such as business shirt fabrics and Middle Eastern folk costumes. There is a drawback.

In addition, Patent Document 3 proposes a manufacturing technology for irregular cross-section fibers with excellent anti-pilling properties using a blend polymer of dialkyl phosphate copolyester and 5-alkali metal isophthalic acid copolyester; proposed a polyester fiber with excellent pilling resistance using a blend polymer of dialkyl phosphate copolyester and polyester copolymerized with isophthalic acid, and Patent Document 5 proposes a polyester fiber made by copolymerizing dialkyl phosphate and aliphatic oxydicarboxylic acid. A polyester fiber with excellent anti-pilling properties and a method for producing the same have been proposed. In these proposals, polyester copolymerized with phosphorus compounds is melt-spun, and the fabric is treated with hot water in the dyeing process after weaving and knitting, thereby reducing the strength and elongation of the fibers and knot strength and improving anti-pilling performance. However, the polyester used is a modified polyester, which has problems such as poor whiteness of the fiber itself, lower strength than regular yarn, and poor tear strength and burst strength of the fabric.

Further, Patent Document 6 proposes an anti-pilling polyester fiber made of a polyester copolymerized with an organosilicon compound of tetrahydrofurfuryl alcohol such as tetrakistetrahydrofurfuryloxysilane or tris[tetrahydrofurfuryloxy]methylsilane. However, in this proposal, copolymerization of the organosilicon compound makes it easy to exhaust the dye, so there is a problem that the color fastness, especially when dyeing deep colors, deteriorates.

Further, Patent Document 7 proposes an anti-pill polyester using a polyester obtained by copolymerizing 5-sodium sulfoisophthalic acid and a trifunctional or tetrafunctional silicate orthoester such as tetraethyl silicate. Similar to Patent Document 6, this dye is easy to exhaust the dye and it is easy to obtain a deep color, but on the contrary, it cannot be said to be preferable in terms of color fastness.

In addition, in Patent Document 8, a fabric made of polyester fibers obtained by a composite spinning method is subjected to a napping treatment to expose the cut fluff on the surface, and then a chemical treatment is performed to dissolve and remove easily soluble components to form ultra-fine fibers. A method has been proposed in which a raised fabric is obtained by forming fibers, dyeing them, and shearing the surface. This proposal removes loose hairs on the surface and leaves only strong hairs to improve wear resistance and achieve excellent anti-pilling properties. There is also the problem of exposure to workers, so it cannot be said to be a preferred embodiment from the perspective of SDGs.

On the other hand, Patent Document 9 discloses a false-twisted yarn consisting of single fibers with a hollow cross section and thick portions and details in the fiber axis direction, the yarn having thick portions in the fiber axis direction of each single fiber and between each single fiber. A polyester false-twisted yarn is described in which the details are randomly present, and furthermore, there is a groove on one side of the thick part that reaches the hollow part of the single fiber in a direction perpendicular to the fiber axis. Furthermore, Patent Document 10 describes a fabric that includes thick and thin yarns (thick and thin filament yarns) and has slits in the thick portion of the thick and thin yarns in a direction perpendicular to the fiber axis. These techniques aim to improve deep color, texture, and water absorption.

These techniques are characterized in that they utilize the fact that slit-like holes are formed in the thick portion when thick and thin (T&T) filaments are subjected to alkali weight reduction processing. These techniques require the use of T&T filaments and are essentially techniques related to long fibers. Since long fibers are less susceptible to pilling than short fibers, there has been no motivation to deviate from the original purpose and try to improve the pilling of short fibers based on these techniques.

Japanese Patent Application Publication No. 2001-192943 Japanese Patent Application Publication No. 2004-183167 Japanese Patent Application Publication No. 8-260243 Japanese Patent Application Publication No. 2016-108702 Japanese Patent Application Publication No. 2001-226825 Special Publication No. 2004-533553 Special Publication No. 2001-512509 Japanese Patent Application Publication No. 9-296355 Japanese Patent Application Publication No. 2006-176902 JP2020-176355A

As a means to improve the anti-pilling properties of polyester fibers, as shown above, proposals focus on making the fibers brittle and suppressing pill growth through chemical treatment, physical treatment, or a combination thereof. However, all of them are accompanied by a decrease in strength and elongation, aesthetics of woven or knitted materials, appearance quality, or color fastness.In addition, those using copolymerized polymers or blended polymers are prone to oligomers and scum. There are concerns that this will occur, and there are problems in terms of costs such as deterioration of spinning operation and high costs. The present invention solves the problems of the prior art, and provides polyester short fibers that are inexpensive and have excellent anti-pilling performance, woven or knitted fabrics containing the same, and methods for producing the same. This is the purpose.

As a result of intensive studies to achieve this objective, the present inventors have found that the surface of polyester short fibers is provided with single-character grooves in directions that are not parallel to the fiber axis, such as perpendicular to the fiber axis or diagonal directions. The inventors have discovered that by creating such a method, the fuzz present on the surface of spun yarns and woven or knitted fabrics can be easily removed, and anti-pilling properties can be easily imparted to spun yarns or woven or knitted fabrics.

The present invention was created based on this knowledge, and has the following configurations (1) to (6).
(1) A short polyester fiber characterized in that the fiber surface has single-character grooves that are not parallel to the fiber axis direction, and the grooves are present at a frequency of 300 or more and 3000 or less per 1 mm of fiber length.
(2) The short polyester fiber according to (1), wherein the average number of crimps of the short polyester fiber is 10 to 30 crimps/25 mm.
(3) The polyester short fibers are composed of an aromatic polyester whose main repeating unit is ethylene terephthalate and have an intrinsic viscosity [η] of 0.45 cm ³ /g or more and 0.90 cm ³ /g or less, and the tensile strength of the polyester short fibers is The length is 0.35 cN/tex or more and 0.65 cN/tex or less, the impulse represented by the product of the tensile strength of the polyester staple fiber and the square root of the elongation rate is 1.20 or more and 2.40 or less, and the knot strength of the polyester staple fiber is The polyester short fiber according to (1) or (2), wherein the polyester short fiber is 0.20 cN/tex or more and 0.55 cN/tex or less.
(4) Consisting of an aromatic polyester containing ethylene terephthalate as the main repeating unit and having an intrinsic viscosity [η] of 0.45 cm ³ /g or more and 0.90 cm ³ /g or less, and has an average number of crimps of 10 to 30/25 mm. The polyester short fibers were treated with 0.1% o. w. f. More than 1.5%o. w. f. The method for producing polyester short fibers according to (1) or (2), characterized in that single-letter grooves that are not parallel to the fiber axis direction are formed on the fiber surface by moist heat treatment in the following treatment liquid.
(5) A woven or knitted fabric containing 50% by mass or more of the short polyester fibers described in (1) or (2), and having a pilling property of grade 3 or higher according to JIS-L1076:2012A.
(6) Consists of an aromatic polyester containing ethylene terephthalate as a main repeating unit and having an intrinsic viscosity [η] of 0.45 cm ³ /g or more and 0.90 cm ³ /g or less, and has an average number of crimps of 10 to 30/25 mm. A woven or knitted fabric containing 50% by mass or more of short polyester fibers is treated with 0.1% o. w. f. More than 1.5%o. w. f. The method for producing a woven or knitted material according to item (5), characterized in that a single character-shaped groove that is not parallel to the fiber axis direction is formed on the fiber surface by performing a moist heat treatment in the following treatment liquid.

According to the present invention, polyester staple fibers having excellent anti-pilling performance can be provided without impairing physical properties such as strength and elongation. In addition, the woven and knitted fabrics using the polyester staple fibers of the present invention can be worn as clothing for a long time without compromising aesthetics or quality, reducing the frequency of replacement clothing and reducing the amount of clothing discarded. , it is also effective from an SDGs perspective.

This is an electron micrograph taken of the surface of a polyester short fiber having a single character-shaped groove formed in the cross-sectional direction of the fiber on the fiber surface. This is an electron micrograph taken of the surface of a polyester short fiber having a single-letter-shaped groove formed on the fiber surface obliquely with respect to the fiber axis direction. This is an electron micrograph taken of the surface of a polyester short fiber having a single-letter-shaped groove formed in parallel to the fiber axis direction on the fiber surface. This is an electron micrograph taken of the surface of polyester staple fibers that have shallow grooves on the fiber surface.

Hereinafter, embodiments of the polyester short fibers and the like of the present invention will be described in detail, but the present invention is not limited thereto.

The polyester short fibers of the present invention are preferably composed of an aromatic polyester resin having ethylene terephthalate as a main repeating unit. Methods for producing such polyester resins include the PTA method, in which terephthalic acid and ethylene glycol are polycondensed at a molar ratio of 1:1, or the DMT method, in which dimethyl terephthalate and ethylene glycol are polycondensed at a molar ratio of 1:1. is publicly known. In addition to terephthalic acid, acid components include aromatic dicarboxylic acids such as 5-sodium isophthalic acid and 2,6-naphthalene dicarboxylic acid, and dicarboxylic acid components such as aliphatic dicarboxylic acids such as sebacic acid, adipic acid, and azelaic acid. It may be polymerized, or it may be copolymerized with, for example, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, etc. in addition to ethylene glycol as a diol component. In addition, titanium dioxide, barium sulfate, silicon dioxide, carbon black, kaolinite, and other naturally derived mineral particles, inorganic pigments, organic pigments, dyes, optical brighteners, ultraviolet absorbers, and antioxidants are also added as necessary. etc. may be kneaded.

The intrinsic viscosity [η] of the polyester resin is preferably 0.45 cm ³ /g or more and 0.90 cm 3 /g or less, more preferably 0.48 cm ³ /g or more and 0.85 cm ³ /g or less, even more preferably 0.48 cm ³ /g or more and 0.85 cm 3 /g or less. It is 52 cm ³ /g or more and 0.80 cm ³ /g or less. When the intrinsic viscosity [η] is smaller than the above range, the melt viscosity of the polyester resin decreases, resulting in poor spinnability and poor operability, as well as the density of single-letter grooves formed on the surface of the polyester short fibers. If the size becomes too large, the physical properties of the resulting yarn will be poor, and there is a risk that it will not be able to maintain practical strength. On the other hand, if it is larger than the above range, the melt viscosity will be high and it will be possible to improve the physical properties to the extent that it can be used for industrial materials, but it will be slightly overspecified for clothing applications and the texture of the fabric will be affected. However, there is a risk that the material will be rough and hard and lack drapability. Furthermore, the density of the single-letter grooves formed on the surface of the polyester short fibers may become too small, resulting in poor anti-pilling properties.

The fiber length of the polyester short fibers of the present invention is preferably 22 mm to 55 mm, more preferably 28 mm to 45 mm, and still more preferably 33 mm to 40 mm. If the fiber length exceeds the above range, the method of making non-woven fabrics and spinning will be extremely limited, making it difficult to use for applications such as clothing and materials. It becomes difficult.

The diameter of the polyester short fibers of the present invention is preferably in the range of 3 μm to 20 μm, more preferably in the range of 5 μm to 15 μm. If the diameter is less than the above range or exceeds the above range, it becomes difficult to form the single-letter groove of the present invention. Further, the shape of the cross section of the fiber is preferably a round cross section, and may be an ellipse or a flat cross section, or may be a polygon having four or more corners such as a quadrilateral. However, in cross sections with protrusions such as various cross sections, even if grooves are formed, the effect of improving anti-pilling performance tends to be reduced.

In order to create linear grooves on the fiber surface that are not parallel to the fiber axis direction, it is necessary to impart a dogleg-shaped buckling deformation to the short fibers. Such a "dog" shaped buckling deformation can be easily imparted by a pressing method or a shaping method that is commonly used to impart crimps to fibers. Compressive deformation occurs in the part buckled in a "dog" shape, and this compressed part undergoes alkali weight loss processing during the subsequent moist heat treatment, resulting in a single character shape in the direction perpendicular to the fiber axis or diagonally. Grooves are more likely to form. The number of single-character grooves can be controlled to some extent by the number of bucklings (average number of crimps) on the short fibers and the strength of buckling. Here, the pushing method uses a device equipped with a stuffing box behind a pair of rolls, and the fibers are pushed in by the rolls, folded in the stuffing box, heated to form a fiber mass, and then cooled and pulled out. The shaping method is a method of imparting crimps to the fibers by passing the fibers through two heated gears.

The average number of crimps of the short polyester fibers is preferably 10 to 30/25 mm, and the larger the number of crimps, the more bulky and diffused reflection on the surface of the fabric. The average number of crimps is more preferably 11 to 25 crimps/25 mm, and even more preferably 12 to 25 crimps/25 mm. If the average number of crimps is less than the above range, there is a risk that the density of single-letter grooves formed on the surface of the short fibers will be reduced, and card passing properties may also be poor. If the average number of crimps exceeds the above range, there is a risk that neps will occur frequently after passing through the card, or the thickness unevenness of the spun yarn will increase significantly, leading to a decrease in high-order processability and quality of the spun yarn. In the case of the indentation method, the average number of crimps of polyester short fibers can be controlled by adjusting various conditions such as the distance between doctor blades, nip roller surface temperature, stuffing pressure, and total tow fineness. In order to properly crimp the fibers and prevent the fibers from breaking, it is preferable that the fiber (tow) temperature immediately before the crimper be about 50°C to 95°C, and the crimper temperature should be about 60°C to 110°C. It is preferable to keep it at a certain level. Generally, the higher the temperature of the crimper, the higher the average number of crimps and the higher the density of single-letter grooves formed on the surface of the short fibers. The crimped short fibers are heated with hot air in a non-tensioned state and dried. Note that the nip pressure is preferably adjusted within a range of 0.2 to 1.0 MPa, more preferably 0.3 to 0.6 MPa. The stuffing pressure is preferably adjusted within a range of 0.05 to 0.6 MPa, more preferably 0.2 to 0.45 MPa. On the other hand, in the case of the shaping method, the average number of crimps of the short polyester fibers can be controlled by adjusting various conditions such as the size of the gear, the surface temperature of the gear, the temperature of the tow, and the processing speed.

In the case of the indentation method, specifically, the spun undrawn yarn is stretched at a draw ratio of 2 to 5 times under steam or in hot water, then subjected to tension heat treatment, and then processed using a push-type crimper or the like. Crimp is used to apply crimp. In the case of the shaping method, specifically, the spun undrawn yarn is stretched at a draw ratio of 2 to 5 times under steam or in hot water, then subjected to tension heat treatment, and then stretched between two heated gears. By passing the fibers through, the fibers are crimped. Next, the stretched tow after being crimped is dried, an aqueous finishing oil solution is applied to the tow by spraying, and the tow is cut to produce short fibers. The cut length of the cut fibers can be from 32 mm to burr cut, and is appropriately selected depending on the purpose. Generally, it is preferable that the fiber cut length is not long in terms of the number of fluffs of the spun yarn, the degree of entanglement of the fluffs, the texture, and the quality of the yarn, and a range of 32 mm to 51 mm is preferable.

Note that when spinning, weaving, weaving, and dyeing are performed, the average number of crimps of the short fibers increases compared to the number of crimps immediately after passing through the crimper. This is because the number of crimps in appearance increases due to weaving crimps and knitting loops due to twisting during spinning and formation of texture during knitting and weaving. This is also because the apparent number of crimps increases as the fiber length shrinks due to heat shrinkage during the dyeing process. The average number of crimps of the polyester short fibers of the present invention in short fibers taken out from spun yarn or finished woven or knitted fabrics is 10 to 30 crimps/25 mm, more preferably 15 to 30 crimps/25 mm.

The tensile strength of the polyester short fibers of the present invention is preferably 0.35 cN/tex or more and 0.65 cN/tex or less, more preferably 0.38 cN/tex or more and 0.65 cN/tex or less, and even more preferably 0.40 cN/tex. tex or more and 0.65 cN/tex or less. If the tensile strength is less than the above range, it will not be possible to maintain the practical strength required for clothing, although it depends on the single fiber fineness, and if it exceeds the above range, the practical strength will be sufficient, but good anti-pilling properties will not be maintained. It may not be possible to secure it. The single fiber fineness is not particularly limited, but for general clothing use, it is preferably 0.03 tex or more and 0.25 tex or less, more preferably 0.05 tex or more and 0.24 tex or less, and still more preferably 0.07 tex or more and 0.07 tex or less. 0.23 tex or less, particularly preferably 0.10 tex or more and 0.20 tex or less.

Further, the impulse represented by the product of the tensile strength and the square root of elongation of the short polyester fiber of the present invention is preferably 1.20 or more and 2.40 or less, more preferably 1.23 or more and 2.30 or less, and even more preferably is 1.25 or more and 2.20 or less. This impulse is a "measure" that indicates the toughness and tenacity of the fiber, and if it is lower than the above range, the physical strength when spun into yarn or fabric will be low, and it will not be possible to maintain practical strength. If it exceeds the above range, the physical strength will be sufficient, but the anti-pilling properties, which is the object of the present invention, will tend to be poor. By controlling this impulse within the above range, it becomes possible to achieve both physical strength and pilling resistance.

Further, the knot strength of the polyester short fibers of the present invention is preferably 0.20 cN/tex or more and 0.55 cN/tex or less, more preferably 0.25 cN/tex or more and 0.52 cN/tex or less, and even more preferably 0. It is 30 cN/tex or more and 0.51 cN/tex or less. If this knot strength is smaller than the above range, the pilling resistance is very good, but the strength of the part where the yarn is tied by hand, such as a fisherman's knot or weaver's knot, with a yarn splicer, mechanical knotter, or by hand, is is weak, and may impede spinning, yarn processing, weaving and knitting operations. If the above range is exceeded, the strength of the knot may be sufficient and the operability of spinning, thread processing, weaving and knitting may be good, but the anti-pilling performance may not be sufficient. By controlling this knot strength within the above range, sufficient anti-pilling performance can be exhibited without impairing the operability of spinning, yarn processing, weaving and knitting.

For the production of fibers, a known melt-spinning method can be employed, but it is also possible to use asymmetric cooling in the cooling region during melt-spinning to give the fibers latent crimp ability. The polyester short fibers of the present invention can achieve the purpose by using chopped fibers, which are end fibers, and short staple fibers as yarns. After the short fibers are melt-spun, they are stretched off-line in a bath, and then buckled and crimped, for example, by a pushing method in a stuffing box, and then cut to a predetermined fiber length. All can be carried out using known methods.

The polyester short fiber of the present invention has a single-character-shaped groove on the fiber surface (fiber side surface) in an oblique direction that is not parallel to the fiber axis direction or in a direction perpendicular to the fiber axis. The linear groove as used in the present invention refers to a void extending from the fiber surface to the inside of the fiber, and is characterized in that the opening on the fiber surface has the largest area, and the opening area gradually decreases as it approaches the inside. , for example, one having a V-shaped or U-shaped groove in the depth direction. The linear groove has a length of 1.0 μm or more, preferably 1.0 μm or more and 5.0 μm or less. Further, the single-letter groove has a depth of 0.1 μm or more, preferably 0.1 μm or more and 1.0 μm or less. Note that when a plurality of character-shaped grooves overlap, it may look like a complicated shape such as a V-shape or an X-shape. In the polyester short fiber of the present invention, the number of single-character grooves formed on the fiber surface is on average 300 to 3000, preferably 400 to 2300, more preferably 500 to 1700, per 1 mm of fiber length. It is preferable that the frequency of occurrence is equal to or less than 1. If there are more single-letter grooves than the above range, the effect of improving bathochromic properties can be expected, but physical properties such as abrasion strength, tear strength, bursting strength, and tensile strength will be extremely reduced, and practical strength will not be maintained. Can not do it. Conversely, if the amount is less than the above range, sufficient anti-pilling performance cannot be maintained. Regarding the length and depth of the single-letter groove, if it is less than the above range, the pilling resistance may not be sufficient, and if the length and depth exceed the above range, the anti-pilling property may not be satisfactory. However, there is a risk that the physical strength will be poor.

A specific example of the single character-shaped groove of the short polyester fibers of the present invention will be further explained with reference to the drawings. The single-letter groove of the present invention refers to a single-letter groove that is not parallel to the fiber axis direction, and includes, for example, a single-letter groove formed in the cross-sectional direction of the fiber as shown in the photograph of FIG. As shown in the figure, a single-letter groove formed diagonally with respect to the fiber axis direction is included. On the other hand, as shown in the photograph of FIG. 3, grooves parallel to the fiber axis are not counted as single-letter grooves in the present invention. In addition, a single-character groove is one in which the length from one end of a linear groove to the other is more than 5 times the width of the groove, and a groove that is shorter than 5 times is counted as a single-character groove. do not. Further, as shown in the photograph of FIG. 4, shallow grooves that do not completely form grooves are not counted as single-character grooves.

As a result of extensive research by the present inventors, by subjecting polyester short fibers that have been given buckling deformation to moist heat treatment in an alkaline environment, it is possible to form single-letter-shaped grooves on the surface of the short fibers. It has been found that the anti-pilling properties can be significantly improved by having these single-letter grooves present in a specific proportion. Note that the moist heat treatment here refers to hot water treatment and steam treatment. Processing machines capable of batch processing such as Obermeyer dyeing machines, beam dyeing machines, wind dyeing machines, jigger dyeing machines, liquid jet dyeing machines, and air jet dyeing machines are suitable for hot water treatment, and more preferably, wind dyeing machines and liquid jet dyeing machines are suitable. Dyeing machines that have a high soft cloth effect tend to create single-letter grooves. Furthermore, it is preferable to use a material that can be processed under high pressure. For example, if an Obermeyer dyeing machine (package type dyeing machine) is used, it can be applied to fibers such as cotton (short fibers), sliver, spun yarn, and woven and knitted fabrics. In addition, by using treated cotton, sliver, or spun yarn and performing blending, interweaving, and interweaving, it is also possible to obtain functionally processed fabrics that have multiple functions, such as by adding new functional processing. . For the steam treatment, a conveyor type L-BOX, J-BOX, long loop type no-tension continuous steamer, or roll-to-roll type continuous steamer can be used. Such a continuous steamer can process fabrics in the form of woven or knitted fabrics.

The treatment temperature of the moist heat treatment is not particularly limited, but is preferably 80°C or higher and 140°C or lower, more preferably 90°C or higher and 135°C or lower, and still more preferably 100°C or higher and 130°C or lower. In the case of hot water treatment, the treatment bath ratio is not particularly limited, but the weight ratio of the object to be treated: bath liquid is preferably 1:5 or more and 1:30 or less, more preferably 1:7 or more and 1:20 or less. be. Specifically, the wet heat treatment is performed during or after immersion in a treatment solution containing a quaternary ammonium salt under alkaline conditions. After the above treatment, it is desirable to treat with an anionic surfactant such as a sulfuric acid ester type, a sulfonic acid type, or a phosphoric acid ester type. If cationizing agents such as quaternary ammonium salts remain in the fibers, various fastness properties such as light fastness and dyeing fastness may deteriorate, so it is effective in terms of quality to carry out so-called "anion return". be.

Quaternary ammonium salts to be used include ammonium hydroxide, ammonium fluoride with a halide ion as a counter ion, ammonium chloride, ammonium bromide, ammonium iodide, sulfate ion, hydrogen sulfate ion, and dichromate ion. Quaternary ammonium salts with monovalent to trivalent negative ions as counter ions are exemplified. Usually, quaternary ammonium salts mostly have properties as cationic surfactants, but amphoteric surfactants such as amidosulfobetaine, such as laurylsulfobetaine, caprylylsulfobetaine, and stearylsulfobetaine, are used as quaternary ammonium salts. The type of activator is also included in the quaternary ammonium salt used in the present invention. Suitable quaternary ammonium salts include benzyldodecyldimethylammonium salt, triethylmethylammonium salt, tetraethylammonium salt, trimethylstearylammonium salt, octyltriethylammonium salt, and the like. Particularly preferred are triethylmethylammonium salt and tetraethylammonium salt.

The amount of quaternary ammonium salt used is preferably 0.1% o. w. f. More than 1.5%o. w. f. Below, more preferably 0.2% o. w. f. More than 1.2%o. w. f. Below, more preferably 0.3% o. w. f. More than 1.0%o. w. f. It is as follows. Since the wastewater containing the quaternary ammonium salt has a high COD, the wastewater load is large, and in consideration of the environment, it is desirable to keep the amount used to the minimum necessary. Furthermore, since the use of a quaternary ammonium salt may result in increased foaming, it is also possible to use a silicone emulsion antifoaming agent or the like in combination.

An organic solvent, a viscosity modifier, an anionic surfactant, a nonionic surfactant, a chelating agent, etc. may be used in combination with the above quaternary ammonium salt. In particular, organic solvents are preferred because they promote groove formation when used together with quaternary ammonium salts. As the type of organic solvent, polybranched higher alcohols, polyhydric alcohol ethers, etc. are preferable. Examples of the polyhydric polybranched higher alcohol include isobutyl alcohol, isopropyl alcohol, and isopentyl alcohol. As the polyhydric alcohol ether, butyl cellosolve, cellosolve, and methyl cellosolve are preferred. These compounds are organic solvents with boiling points ranging from approximately 100°C to 180°C, but with the exception of isopropyl alcohol and isobutyl alcohol, their boiling points are higher than the processing temperature, so the increase in internal pressure during batch processing remains small. The prescribed amount is such that the concentration of polyhydric alcohol ether is 0.005% sol. 0.050% sol. Below, the concentration of the multi-branched higher alcohol is 0.005% sol. 0.050% sol. The following extremely small amount is sufficient. Although the amount used does not fall under the Organic Solvent Poisoning Prevention Regulations (Organic Regulations), it is important to give careful consideration to the working environment, such as general ventilation and local ventilation, and to keep the exposure of workers as low as possible as part of the SDGs. It is also necessary from this point of view.

Furthermore, in order to achieve alkaline conditions, hydroxides and carbonates of alkali metals and alkaline earth metals, such as sodium hydroxide, sodium carbonate, potassium hydroxide, and potassium carbonate, are preferably used. Taking sodium hydroxide as an example of the solution concentration in a treatment bath in moist heat treatment, the prescribed amount is preferably 0.10% sol. More than 0.50% sol. More preferably 0.15% sol. More than 0.30% sol. It is as follows. These prescription amounts are extremely small, and the conditions are not such that the alkali weight loss due to alkaline hydrolysis of polyester will actively proceed, so the effects such as an extremely small fiber diameter will remain as small as possible. .

The above-mentioned moist heat treatment applied to the short polyester fibers may be performed with the short polyester fibers in the form of cotton, sliver or spun yarn. Further, it may be carried out in the form of woven or knitted fabrics or nonwoven fabrics, or in the form of final products such as sewn products. The wet heat treatment may be performed using a dyeing machine that is suitable for the form of the polyester short fibers. Note that other fibers may be mixed with the short polyester fibers at the time of performing the moist heat treatment.

Polyester short fibers are reduced in weight by moist heat treatment under alkaline conditions, but as the weight loss rate increases, more grooves are generated. The maximum number of single-letter grooves that can be formed on the fiber is thought to depend on the strength of the buckling process and the number of crimps, but it also changes depending on the selection of processing machine, processing conditions, and weight loss rate. The weight loss rate is preferably 3 to 30%, more preferably 5 to 20%, and still more preferably 8 to 15%. If the weight loss rate is less than the above range, the number of single character grooves will be too small, and if it exceeds the above range, the number of single character grooves will remain high and the fiber strength will tend to decrease significantly.

When producing spun yarn from the polyester short fibers of the present invention, the blending ratio of the polyester short fibers is preferably 50 to 100% by mass. More preferably, it is 60% by mass or more. More preferably, it is 80% by mass or more. When the blending ratio of the polyester staple fibers of the present invention is less than the above range, the anti-pilling effect of the polyester staple fibers of the present invention in the final product tends to decrease. Further, when making a woven or knitted fabric using the spun yarn of the polyester short fibers of the present invention, the blending ratio of the polyester short fibers contained in the woven or knitted fabric is preferably 50 to 100% by mass, more preferably 55% by mass or more. , more preferably 60% by mass or more. If the blending ratio of polyester short fibers in the woven or knitted fabric is less than the above range, the anti-pilling effect of the final product tends to decrease. Incidentally, the total fineness of the spun yarn containing polyester short fibers may be appropriately set depending on the desired woven or knitted fabric, and is preferably manufactured within the range of English size 5 to 100, for example. The English count of the spun yarn can be measured as the apparent cotton count of the English count according to JIS-L1095 (2010) 9.4.2.

As mentioned above, the polyester short fibers of the present invention may be subjected to moist heat treatment under alkaline conditions to form single-character grooves, and then subjected to spinning, nonwoven fabrics, woven or knitted fabrics, or yarn or nonwoven fabrics. After obtaining the woven or knitted fabric, a moist heat treatment under alkaline conditions may be applied to form a single-letter groove. In particular, it is preferable to treat the fibers in the form of cotton or yarn because the range of applications can be expanded to include blending with other fibers, blending, interweaving, and interweaving. In addition, when obtaining a woven or knitted fabric, it is also possible to perform known processing such as gray wool burning treatment or raising treatment as necessary.

The structure of the woven or knitted fabric of the present invention is not limited, but examples of the woven fabric include those having a woven structure such as plain weave, twill weave, satin weave, multiple weave, dobby weave, and jacquard weave. The woven fabric may be made into patterns such as stripes or checks by using a plurality of yarn-dyed yarns of different colors, or may be woven into patterns using a jacquard loom. In particular, when the fabric is used for clothing such as shirt fabrics and blouse fabrics, plain weave and twill weave are preferred. Weft knitting (circular knitting) includes, for example, jersey knitting (flat knitting), bare jersey knitting, welted jersey knitting, milling knitting (rubber knitting), pearl knitting, single-bag knitting, smooth knitting, tuck knitting, floating knitting, and single-sided knitting. Examples include those with knitting structures such as knitting, lace knitting, and crimped knitting. Among these, jersey knitting, tuck knitting (pique knitting), milling knitting, and smooth knitting are preferred. Examples of warp knitting include knitting structures such as single denby knitting, open denby knitting, single atlas knitting, double cord knitting, half knitting, half base knitting, satin knitting, tricot knitting, half tricot knitting, russell knitting, and jacquard knitting. Examples include those having the following.

Regarding the pilling test, according to the 2012 edition JIS-L1076.8.1.1 method A (method using an ICI type tester), the operation was performed for 10 hours for woven fabrics and 5 hours for knitted fabrics, and in accordance with 9.2 of the same. As described, the grade is determined by referring to the pilling determination standard photograph. By using the polyester short fibers with excellent anti-pilling properties of the present invention, the pilling test grade can be set to 3-4 or higher, preferably 4 or higher, and more preferably 4-5. .

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these descriptions. The characteristic values in the Examples are evaluated based on the following measurement method.

(intrinsic viscosity)
Polyester resin was dissolved in a mixed solvent of phenol/1,1,2,2-tetrachloroethane (60/40 (weight ratio)), and an Ubbelohde viscometer placed in a constant temperature water bath adjusted to 30 ± 2°C was used. The intrinsic viscosity (cm ³ /g) was determined by the four-point dilution method. To further explain the intrinsic viscosity, the intrinsic viscosity of a polymer depends on the molecular weight of the polymer, and the Mark-Houwink-Sakurada formula [η]=KM ^α holds true. When the viscosity of the polymer solution is η, the viscosity of the solvent is η _s , and the unit concentration of the polymer is c, the reduced viscosity η _red can be expressed as η _red = [(η-η _s )/η _s ]/c, The intrinsic viscosity [η] can be determined by extrapolating the reduced viscosity η _red so that the polymer concentration c becomes c→0. Experimentally, the intrinsic viscosity [η] can be determined from the time the fluid flows down the capillary of an Ubbelohde viscometer. When the flow time of the polymer solution is t and the flow time of the solvent is t _s , the reduced viscosity η is _red can be expressed as η _red =(t−t _s )/t _s c using the flow time t and polymer concentration c.

(single fineness)
Measured according to the method described in JIS-L1015:2010 8.5.1 Method B (simple method).

(Fiber length of short fiber)
It was measured according to the method described in JIS-L1015:2010 8.4 Fiber Length Method C (direct method).

(knot strength of short fibers)
Measured according to the method described in JIS-L1015:2010 8.8.1 Standard Time Test. The type of testing machine was a constant speed extension type, the grip interval was 10 mm, the tensile speed was 10 mm/min, and the measured value was the arithmetic mean value of 10 tests.

(Tensile strength and elongation rate of short fibers)
Measured according to the method described in JIS-L1015:2010 8.7.1 Standard Time Test. The type of testing machine was a constant speed extension type, the grip interval was 10 mm, the tensile speed was 10 mm/min, and the measured value was the arithmetic mean value of 10 tests.

(impulse of short fibers)
Impulse was determined from the tensile strength (DT) and elongation (DE) using the following equation 1.
Impulse = DT×√DE (Formula 1)

(Number of crimps of short fibers)
It was measured according to the method described in JIS-L1015:2010 8.12.1 (number of crimp).

(Tensile strength of woven or knitted material)
Measured according to the method described in JIS-L1096:2010 8.14.1 Method A (strip method).

(Tear strength of textile)
Measured according to the method described in JIS-L1096:2010 8.17.4 D method (pendulum method).

(Rupture strength of knitted fabric)
Measured according to the method described in JIS-L1096:2010 8.18.1A Mullen method.

(slip resistance)
Measurement was performed according to the method described in JIS-L1096:2010 8.23.1 B method with a load of 79.0N.

(Pilling test of woven and knitted fabrics)
According to the method described in JIS-L1076:2012 8.1.1 Method A (method using an ICI type tester), the operation was carried out for 10 hours for woven fabric samples and 5 hours for knitted fabric samples, and based on the pilling judgment standard photograph, The grade was determined.

(Measurement of the number of grooves in a single character)
The processed cotton, spun yarn, or woven or knitted fabric after the alkali treatment was decomposed to collect short polyester fibers. In the case of spun yarn or woven or knitted fabrics, 10 short fibers located on the surface exposed to the outside air were collected. The fiber length of the collected short fibers was determined using the JIS-L1015 8.4 C method. Thereafter, one of the collected short fibers was fixed to a black mount with cellophane tape at both ends, and markings were made with a magic pen at intervals of 0.5 cm in the center of the fiber. Using an optical microscope (Keyence VH-Z100UR) at a magnification of 1000x, observe the markings on one short fiber from one side to the other, and check for single-character grooves that are not parallel to the fiber axis direction when viewed from one side. I counted the numbers. The counted number of grooves was divided by the length between markings (5 mm) and then doubled to calculate the number of grooves per 1 mm of the entire circumference. The same procedure was carried out for the remaining nine fibers that were collected, and the arithmetic mean value was taken, which was defined as the number of grooves per 1 mm of fiber length. Note that a single-letter groove is a groove formed by a single letter extending from the fiber surface to the inside of the fiber, and is counted as a groove in which the opening on the fiber surface has the largest area and the opening area gradually decreases as it reaches the inside. In addition, single-letter grooves that are completely present in the observation field are not counted if they are less than 1.0 μm in length, and character-shaped grooves that are at the end of the observation field are counted if they are less than 0.5 μm in length. Suppose there is no. Furthermore, grooves with a depth of less than 0.1 μm are not counted.

[Example 1]
Using polyethylene terephthalate semidull pellets (containing 0.2% by weight of titanium dioxide) with an intrinsic viscosity [η] of 0.63 cm ³ /g, the single yarn fineness was determined by a known melt spinning method at a spinning take-off speed of 1500 m/min. A semi-dual polyester undrawn yarn (tow) having a round cross section of 4.5 decitex was obtained. This undrawn polyester yarn (tow) was drawn off-line in a bath. The stretching ratio was 3.0 times, and the stretching bath temperature was 70°C. Next, a buckling crimp with an average number of 15.5 crimps/25 mm was applied by the pressing method using a stuffing box at a crimper temperature of 70°C, and then cut to a constant length of 38 mm, and a 1.5 decitex 38 mm cut. Polyester semi-dull staple fibers were obtained.

The obtained polyester short fibers are put into an Obermeyer dyeing machine (package type dyeing machine) manufactured by Hisaka Seisakusho Co., Ltd., and first, anionic surfactants are the main component under alkaline conditions at a treatment bath temperature of 80°C. After performing scouring treatment with a scouring agent of was processed while circulating the liquid from in to out and out to in. After draining the liquid, it was washed with hot water and water, and then treated with Honol MGR, a spinning oil manufactured by Takemoto Yushi Co., Ltd., in a bath, and after draining, it was dehydrated and dried to obtain a heat-and-moisture treated cotton made of short polyester fibers. Table 1 shows the details of the solution used during the moist heat treatment and the details of the obtained polyester short fibers.

Using 100% of this moist heat-treated cotton of short polyester fibers, a polyester spun yarn of English cotton count No. 24 single yarn was obtained by a known and conventional ring spinning method. The resulting No. 24 single yarn polyester spun yarn was used as the warp and weft, and was woven into a plain weave using an air jet loom model JAT810 manufactured by Toyota Industries, Ltd. to obtain a woven fabric. The obtained greige fabric was subjected to conventional greige burning, continuous scouring, continuous alkali reduction processing, and continuous dyeing, and then a primary antistatic agent was added to obtain a dyed fabric. The finishing density is 88 threads/inch in the warp and 82 threads/inch in the weft, the tensile strength is 660N in the warp direction and 790N in the weft direction, the tear strength is 33.0N in the warp direction and 42.0N in the weft direction, and the slip resistance is 1. 0 mm, 1.0 mm in the weft direction, and a pilling grade of 4.5, a fabric suitable for general clothing such as shirts, uniforms, and Middle Eastern folk costumes was obtained, which had both practical strength and anti-pilling performance. Details of the obtained fabric are shown in Table 1.

[Example 2]
Polyester short fibers and a woven fabric were obtained in the same manner as in Example 1, except that the crimper temperature was changed to 80° C. and the average number of crimps of the polyester short fibers was changed to 20.5 pieces/25 mm. Details of the obtained polyester short fibers and fabrics are shown in Table 1. The short polyester fibers and fabric of Example 2 had the same high level of practical strength and anti-pilling performance as those of Example 1.

[Example 3]
Polyester short fibers and a woven fabric were obtained in the same manner as in Example 1, except that the blend ratio of the polyester staple fibers of the present invention in the woven fabric was changed to 65%. Specifically, a 1.5 decitex 38 mm cut of the moist heat-treated polyester short fiber obtained in Example 1 and cotton (upland cotton) were mixed in a draw blend at a weight ratio of 65:35, and then spun by a known ring spinning method. English style cotton count 30 count single yarn and 20 count single yarn were obtained. Using the No. 30 single yarn spun yarn as the warp and the No. 20 single yarn as the weft, weaving was carried out in a 2/2 twill weave (left twill) to obtain a woven fabric. The obtained greige fabric was subjected to conventional greige burning, continuous scouring, and continuous dyeing, and then a primary antistatic agent was added to obtain a dyed fabric. Details of the obtained polyester short fibers and fabrics are shown in Table 1. The short polyester fibers and fabric of Example 3 had the same high practical strength and anti-pilling performance as those of Example 1.

[Example 4]
Polyester short fibers and woven fabrics were obtained in the same manner as in Example 1, except that the processing machine used for the moist heat treatment, the time of the moist heat treatment, the type of chemical used, and the prescribed amount were changed as shown in Table 1. Specifically, using 100% of the polyester short fibers of Example 1, a polyester spun yarn of English cotton count No. 24 single yarn was obtained by a known and conventional ring spinning method. The obtained polyester spun yarn of No. 24 single yarn was used as the warp and weft, and was woven into a plain weave using an air jet loom model JAT810 manufactured by Toyota Industries, Ltd. to obtain a woven fabric. The obtained textile greige was subjected to conventional greige wool burning and continuous scouring, and then subjected to wet heat treatment at a bath ratio of 1:10 and a moist heat treatment temperature of 120°C using a jet dyeing machine manufactured by Hisaka Seisakusho Co., Ltd. (trade name: Circular). The cloth was subjected to moist heat treatment under the chemical conditions shown in Table 1, dehydrated, washed with hot water, washed with water, subjected to liquid alkali weight loss, and subjected to continuous dyeing, and then a primary antistatic agent was applied to obtain a dyed cloth. Details of the obtained polyester short fibers and fabrics are shown in Table 1. The short polyester fibers and fabric of Example 4 had the same high level of practical strength and anti-pilling performance as those of Example 1.

[Example 5]
Polyester short fibers and a woven fabric were obtained in the same manner as in Example 4, except that the blend ratio of the polyester short fibers of the present invention in the woven fabric was changed to 50%. Specifically, using 100% of the polyester short fibers of Example 4, a polyester spun yarn of English cotton count No. 24 single yarn was obtained by a known and conventional ring spinning method. The obtained polyester spun yarn of No. 24 single yarn was used as the warp yarn, and the spun yarn of English style cotton count of No. 24 single yarn made of 100% upland cotton was used for the weft yarn, using an air jet loom JAT810 model manufactured by Toyota Industries Corporation. A plain weave was obtained using a woven fabric. The obtained textile greige was subjected to conventional greige wool burning and continuous scouring, and then subjected to wet heat treatment at a bath ratio of 1:10 and a moist heat treatment temperature of 120°C using a jet dyeing machine manufactured by Hisaka Seisakusho Co., Ltd. (trade name: Circular). The cloth was subjected to moist heat treatment under the chemical conditions shown in Table 1, dehydrated, washed with hot water, washed with water, subjected to liquid alkali weight loss, and subjected to continuous dyeing, and then a primary antistatic agent was applied to obtain a dyed cloth. Details of the obtained polyester short fibers and fabrics are shown in Table 1. The short polyester fibers and fabric of Example 5 had the same high level of practical strength and anti-pilling performance as those of Example 4.

[Example 6]
The ring-spun yarn made of 100% polyester short fibers made of English cotton count 24 single yarn produced in Example 4 was subjected to a knit wax finish. Using this spun yarn, a front pique was produced using a 26-inch 28G (gauge) single circular knitting machine manufactured by Fukuhara Seiki Co., Ltd. with a yarn length of 265 mm/100 wales. This gray fabric was opened and preset at 180°C for 60 seconds using a tenter. After that, scouring was carried out using a jet dyeing machine manufactured by Hisaka Seisakusho in the usual manner, followed by wet heat treatment at a bath ratio of 1:10, a wet heat treatment temperature of 120°C, and the chemical conditions shown in Table 1, followed by hot and cold washing. It was then neutralized with acetic acid. After that, without taking the fabric out of the dyeing machine, it was dyed under high pressure (130°C x 30 minutes) using a disperse dye (C.I. Disperse Blue 165 0.5% o.w.f.) and a dispersant using a conventional method. ), then soaping, washing with hot water and water, and taking it out from the dyeing machine. Thereafter, after centrifugal dehydration and spreading, an antistatic agent was applied wet-on-wet using a padder, and a final set (160° C. x 90 seconds) was performed using a tenter to finish. The finished knitted fabric had 36 courses, 33 wales, and a basis weight of 185 g/m ² . Details of the obtained knitted fabric are shown in Table 1. The short polyester fibers and knitted fabric of Example 6 had the same high level of practical strength and anti-pilling performance as those of Example 4.

[Example 7]
Using polyethylene terephthalate full-dull pellets (containing 2.0% by weight of titanium dioxide) with an intrinsic viscosity [η] of 0.62 cm ³ /g, a single yarn fineness of 4 was produced using a known melt spinning method at a spinning take-off speed of 1500 m/min. A polyester full-dull trilobal cross-section undrawn yarn (tow) having a density of .5 decitex was obtained. This undrawn polyester yarn (tow) was drawn off-line in a bath. The stretching ratio was 3.0 times, and the stretching bath temperature was 70°C. Next, a buckling crimp with an average number of 12.5 crimps/25 mm was applied by the pressing method using a stuffing box at a crimper temperature of 70°C, and then cut to a constant length of 38 mm, and a 1.5 decitex 38 mm cut. Polyester full-dull staple fibers were obtained.

Polyester short fibers and woven fabrics were obtained in the same manner as in Example 1, except that the types and prescription amounts of the chemicals used in the moist heat treatment were changed as shown in Table 1. The finishing density is 87 threads/inch in the warp and 83 threads/inch in the weft, the tensile strength is 650N in the warp direction and 765N in the weft direction, the tear strength is 31.5N in the warp direction and 40.5N in the weft direction, and the slip resistance is 1. 0 mm, 1.2 mm in the weft direction, and a pilling grade of grade 4, a fabric suitable for general clothing such as shirts, uniforms, and Middle Eastern folk costumes was obtained that had both practical strength and anti-pilling performance. Details of the obtained fabric are shown in Table 1.

[Example 8]
Polyethylene terephthalate bright pellets (containing 0.02% by weight of titanium dioxide) with an intrinsic viscosity [η] of 0.54 cm ³ /g were used to obtain a single yarn fineness of 4 using a known melt spinning method at a spinning take-off speed of 1500 m/min. A polyester bright triangular cross-section undrawn yarn (tow) having a density of .5 decitex was obtained. This undrawn polyester yarn (tow) was drawn off-line in a bath. The stretching ratio was 3.0 times, and the stretching bath temperature was 70°C. Next, a buckling crimp with an average number of 22.5 crimps/25 mm was applied by the pressing method using a stuffing box at a crimper temperature of 70°C, and then cut to a constant length of 38 mm, and a 1.5 decitex 38 mm cut. Polyester bright short fibers were obtained.

Polyester staple fibers and woven fabrics were obtained in the same manner as in Example 3, except that the types and prescription amounts of the chemicals used in the moist heat treatment were changed as shown in Table 1. The finishing density is 152 lines/inch in the warp and 63 lines/inch in the weft, the tensile strength is 600N in the warp direction and 750N in the weft direction, the tear strength is 36.5N in the warp direction and 32.0N in the weft direction, and the slip resistance is 1. 5 mm, 1.3 mm in the weft direction, and a pilling grade of 4.5, a fabric suitable for general clothing such as shirts, uniforms, and Middle Eastern folk costumes was obtained, which had both practical strength and anti-pilling performance. Details of the obtained fabric are shown in Table 1.

[Example 9]
Using polyethylene terephthalate semidull pellets (containing 0.2% by weight of titanium dioxide) with an intrinsic viscosity [η] of 0.77 cm ³ /g, the single yarn fineness was determined by a known melt spinning method at a spinning take-off speed of 1500 m/min. A semi-dual polyester undrawn yarn (tow) having a round cross section of 4.5 decitex was obtained. This undrawn polyester yarn (tow) was drawn off-line in a bath. The stretching ratio was 3.0 times, and the stretching bath temperature was 70°C. Next, a buckling crimp with an average number of 14.5 crimps/25 mm was applied by the pressing method using a stuffing box at a crimper temperature of 80°C, and then cut to a constant length of 38 mm, and a 1.5 decitex 38 mm cut. Polyester semi-dull staple fibers were obtained.

Polyester short fibers and woven fabrics were obtained in the same manner as in Example 1, except that the types and prescription amounts of the chemicals used in the moist heat treatment were changed as shown in Table 1. The finishing density is 88 threads/inch in the warp and 82 threads/inch in the weft, the tensile strength is 720N in the warp direction and 850N in the weft direction, the tear strength is 38.5N in the warp direction and 47.0N in the weft direction, and the slip resistance is 1. 0 mm, 1.2 mm in the weft direction, and a pilling grade of grade 4, a fabric suitable for general clothing such as shirts, uniforms, and Middle Eastern folk costumes was obtained that had both practical strength and anti-pilling performance. Details of the obtained fabric are shown in Table 1.

[Comparative example 1]
Bright pellets of polyethylene terephthalate copolymer having an intrinsic viscosity [η] of 0.42 cm ³ /g and copolymerized with 10 mol% of 5-sodium sulfoisophthalic acid as an aromatic dicarboxylic acid component (containing 0.02% by weight of titanium dioxide). ) was used as the raw material pellets, but in the same manner as in Example 1, a moist heat-treated cotton of short polyester fibers was obtained. Table 1 shows the details of the solution used during the moist heat treatment and the physical properties of the obtained polyester short fibers.

A dyed cloth was obtained in the same manner as in Example 1 using 100% of this moist heat treated cotton of short polyester fibers. Details of the obtained fabric are shown in Table 1. Although the woven fabric of Comparative Example 1 had excellent anti-pilling performance, it could not maintain a performance that could withstand practical use in terms of fabric strength, and was not suitable for use in shirts or uniforms.

[Comparative example 2]
A moist heat-treated cotton made of short polyester fibers was obtained in the same manner as in Example 1 except that polyethylene terephthalate semidull pellets (containing 0.2% by weight of titanium dioxide) having an intrinsic viscosity of 0.95 cm ³ /g were used. Table 1 shows the conditions of the solution used during the moist heat treatment and the physical properties of the obtained fibers.

A dyed cloth was obtained in the same manner as in Example 1 using 100% of this moist heat treated cotton of short polyester fibers. Details of the obtained fabric are shown in Table 1. Although the fabric of Comparative Example 2 had good physical strength, it was a step short in terms of the targeted anti-pilling performance.

[Comparative example 3]
The procedure was the same as in Example 1, except that the crimper temperature was changed to 50°C and the crimping conditions were changed to lower the total tow fineness introduced into the crimper so that the average number of crimps of the short polyester fibers was 8.0 pieces/25 mm. Polyester staple fibers and woven fabrics were obtained. Details of the obtained polyester short fibers and fabrics are shown in Table 1. The fabric of Comparative Example 3 retained sufficient physical properties for use in general clothing, but the pilling grade was low, which predicted deterioration in appearance quality when worn repeatedly, and although this was not a desirable embodiment. It became a fabric that was not used.

Even when the polyester short fibers of the present invention are used in woven or knitted clothing such as shirts and uniforms and worn repeatedly, pilling does not occur easily and the aesthetics and quality are not impaired. In addition, because it does not sacrifice the physical properties necessary for clothing fibers, it can be worn for a long time as clothing, reduces the frequency of replacement, and reduces the amount of waste, which is also effective from a sustainability perspective. .

Claims (6)

1. A polyester staple fiber, characterized in that the fiber surface has linear grooves that are not parallel to the fiber axis direction, and the grooves are present at a frequency of 300 or more and 3000 or less per 1 mm of fiber length. The short polyester fiber according to claim 1, wherein the average number of crimps of the short polyester fiber is 10 to 30 crimps/25 mm. The short polyester fibers are composed of an aromatic polyester whose main repeating unit is ethylene terephthalate and have an intrinsic viscosity [η] of 0.45 cm ³ /g or more and 0.90 cm ³ /g or less, and the tensile strength of the polyester short fibers is 0. .35 cN/tex or more and 0.65 cN/tex or less, the impulse represented by the product of the tensile strength of the polyester staple fiber and the square root of the elongation rate is 1.20 or more and 2.40 or less, and the knot strength of the polyester staple fiber is 0. The short polyester fiber according to claim 1 or 2, characterized in that it has a density of 20 cN/tex or more and 0.55 cN/tex or less. A polyester composed of an aromatic polyester whose main repeating unit is ethylene terephthalate and whose intrinsic viscosity [η] is 0.45 cm ³ /g or more and 0.90 cm ³ /g or less, and whose average number of crimps is 10 to 30/25 mm. The short fibers are treated with 0.1% o. w. f. More than 1.5%o. w. f. 3. The method for producing polyester short fibers according to claim 1, wherein a single-letter groove not parallel to the fiber axis is formed on the fiber surface by performing a moist heat treatment in the following treatment liquid. A woven or knitted fabric containing 50% by mass or more of the short polyester fiber according to claim 1 or 2, and having a pilling property of grade 3 or higher according to JIS-L1076:2012A method. A polyester composed of an aromatic polyester whose main repeating unit is ethylene terephthalate and whose intrinsic viscosity [η] is 0.45 cm ³ /g or more and 0.90 cm ³ /g or less, and whose average number of crimps is 10 to 30/25 mm. A woven or knitted fabric containing 50% by mass or more of short fibers is treated with 0.1% o. w. f. More than 1.5%o. w. f. 6. The method for producing a woven or knitted material according to claim 5, wherein a groove in the shape of a single letter not parallel to the fiber axis is formed on the surface of the fiber by performing a moist heat treatment in the following treatment liquid.