polyester fiber

Abstract

To provide a polyester fiber excellent in dyeability and fastness to light.SOLUTION: A polyester fiber is configured of polyester resin, where the polyester resin is a copolymer composed of a dicarboxylic acid component and a glycol component. Of the glycol component, 95-99.87 mol% is ethylene glycol and / or an ester-forming derivative thereof and 0.13-5 mol% is 1,2-propanediol and / or an ester-forming derivative thereof.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polyester fiber having excellent dyeability and lightfastness. [Background technology]

[0002] Polyester fibers are used in a variety of fields, primarily in clothing, due to their mechanical properties, dyeability, and ease of handling. However, polyester fibers generally have poor dyeability due to their dense fiber structure, and polyester fibers with better dyeability are in demand. Therefore, numerous methods have been investigated to improve dyeability by modifying the dicarboxylic acid component or glycol component of polyester resin. For example, Patent Document 1 (International Publication No. WO2011 / 068195) discloses room-temperature dyeable polyester fibers obtained by modifying a dicarboxylic acid component. Also, Patent Document 2 (Japanese Patent Laid-Open Publication No. 2009-209145) and Patent Document 3 (International Publication No. WO2013 / 035559) disclose polyester fibers obtained from polyester resins modified by modifying or incorporating a component derived from 1,2-propanediol, a glycol component. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. WO2011 / 068195 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-209145 [Patent Document 3] International Publication No. WO2013 / 035559 Summary of the Invention [Problem to be solved by the invention]

[0004] However, although the polyester fiber described in Patent Document 1 can be dyed at room temperature, it has a lower melting point and lower heat resistance than polyethylene terephthalate fiber, which can result in insufficient spinnability. Furthermore, the polytrimethylene terephthalate fiber obtained from 1,2-propanediol and terephthalic acid described in Patent Document 2 has superior dyeability and fluidity compared to polyethylene terephthalate fiber, but has problems with lightfastness. Furthermore, due to its low melting point and poor heat resistance, it can also result in insufficient spinnability. The polyester fiber described in Patent Document 3 has improved heat resistance by limiting the content of 1,2-propanediol-derived components in the polyester to 15 to 500 ppm, which reduces spinneret fouling and increases production efficiency, but has problems with lightfastness.

[0005] Therefore, an object of the present invention is to solve the above problems and to provide a polyester fiber having excellent dyeability and lightfastness. [Means for solving the problem]

[0006] The present inventors have conducted extensive research to achieve the above object and have arrived at the present invention, which provides the following preferred embodiments. [1] A polyester fiber made of a polyester resin, characterized in that the polyester resin is a copolymer consisting of a dicarboxylic acid component and a glycol component, and that 95 to 99.87 mol % of the glycol component is ethylene glycol and / or an ester-forming derivative thereof, and 0.13 to 5 mol % is 1,2-propanediol and / or an ester-forming derivative thereof. [2] A fiber structure at least partially comprising the polyester fiber described in [1]. [Effects of the Invention]

[0007] According to the present invention, a polyester fiber having excellent dyeability and lightfastness can be provided. DETAILED DESCRIPTION OF THE INVENTION

[0008] The polyester resin used in the polyester fiber of the present invention is a copolymer consisting of a dicarboxylic acid component and a glycol component, in which 95 to 99.87 mol % of the glycol component is ethylene glycol and / or its ester-forming derivative, and 0.13 to 5 mol % is 1,2-propanediol and / or its ester-forming derivative.

[0009] Of the glycol components of the polyester resin used in the present invention, 95 to 99.87 mol % is ethylene glycol and / or its ester-forming derivatives. If the ethylene glycol and / or its ester-forming derivatives are less than the above lower limit, not only will heat resistance and spinnability decrease, but lightfastness will also decrease, significantly impairing the excellent fiber properties inherent to polyester fibers. If the ethylene glycol and / or its ester-forming derivatives exceed the above upper limit, dyeability will decrease. The ethylene glycol and / or its ester-forming derivatives are preferably 97.5 to 99.85 mol %, more preferably 98 to 99.83 mol %.

[0010] Of the glycol components of the polyester resin used in the present invention, 0.13 to 5 mol % is 1,2-propanediol and / or its ester-forming derivatives. If the content of 1,2-propanediol and / or its ester-forming derivatives exceeds the upper limit, the heat resistance of the polyester deteriorates, resulting in poor spinnability, and the quality of the textile product deteriorates. Furthermore, the melting point of the resulting fiber decreases, resulting in poor durability, such as iron resistance. Furthermore, when the resulting fiber is dyed, its lightfastness deteriorates. If the content of 1,2-propanediol and / or its ester-forming derivatives is less than the lower limit, the heat resistance of the polyester deteriorates, resulting in poor spinnability, and the quality of the textile product deteriorates, resulting in insufficient dyeability. The content of 1,2-propanediol and / or its ester-forming derivatives is preferably 0.14 to 4 mol %, and more preferably 0.15 to 3 mol %.

[0011] The reason for improved dyeability without a decrease in lightfastness is not yet clearly understood, but it is thought that this is because the methyl groups of 1,2-propanediol incorporated into the polymer molecular skeleton form appropriate gaps between molecules, increasing the number of dye adsorption sites in the amorphous region, as long as the polymer glass transition temperature does not decrease significantly. Also, the reason for high lightfastness is thought to be that, like ether bonds, light energy is absorbed and the molecular skeleton is cleaved, preventing the generation of oxygen radicals that would have a negative effect on dyefastness.

[0012] The content of 1,2-propanediol and / or its ester-forming derivatives in the copolymerization components is determined from the total amount of 1,2-propanediol and / or its ester-forming derivatives detected when the polyester resin is decomposed and analyzed, and this represents the total amount including not only 1,2-propanediol and / or its ester-forming derivatives having a 1,2-propanediol-derived structure copolymerized in the polymer chain, but also 1,2-propanediol and / or its ester-forming derivatives mixed between the polymers.

[0013] The dicarboxylic acid component, which is a monomer of the polyester resin used in the present invention, is preferably a dicarboxylic acid and / or its ester-forming derivative, such as terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4'-dicarboxylic acid, and their ester-forming derivatives. The ester-forming derivatives referred to in the present invention include lower alkyl esters, acid anhydrides, and acyl chlorides of these dicarboxylic acids, with methyl esters, ethyl esters, and hydroxyethyl esters being preferred. A more preferred embodiment of the dicarboxylic acid and / or its ester-forming derivative used in the present invention is terephthalic acid and / or its dimethyl ester.

[0014] Copolymerization components of the polyester resin used in the present invention include, for example, dicarboxylic acid components such as aromatic dicarboxylic acids and ester-forming derivatives thereof, such as isophthalic acid, 5-sulfoisophthalic acid salts (lithium 5-sulfoisophthalic acid salt, potassium 5-sulfoisophthalic acid salt, sodium 5-sulfoisophthalic acid salt, etc.), phthalic acid, and naphthalene-2,6-dicarboxylic acid, and aliphatic dicarboxylic acids and ester-forming derivatives thereof, such as succinic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, and 1,12-dodecanedicarboxylic acid.

[0015] Furthermore, as a copolymerization component of a polyester in which ethylene glycol is the diol component, not only 1,2-propanediol but also other diol components such as 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, polyoxyalkylene glycols (such as polyethylene glycol) having a molecular weight of 500 to 20,000, diethylene glycol, 2-methyl-1,3-propanediol, bisphenol A-ethylene oxide adducts, and cyclohexanedimethanol may be copolymerized within a range that does not impair the physical properties of the polyester fiber of the present invention, but the copolymerization component may be only 1,2-propanediol and / or its ester-forming derivatives.

[0016] The dicarboxylic acid component and glycol component used in the present invention may be derived from petroleum or biomass. Since biomass-derived ethylene glycol often contains 1,2-propanediol, ethylene glycol derived from biomass resources whose content has been adjusted by purification can also be used. Furthermore, the raw material for the polyester fiber used in the present invention may be a chemically recycled monomer or oligomer.

[0017] The polyester resin used in the present invention is produced by a conventional method. For example, during the direct esterification reaction, it is preferable to maintain the reaction temperature at 250°C or less and the pressure at 1.2 x 100,000 Pa or more. In the subsequent polycondensation reaction, the reaction temperature is preferably 280°C or less and the pressure is preferably reduced as the polymerization time becomes shorter, but it is preferable to maintain the pressure at 110 Pa or more. At higher temperatures and lower pressures in each reaction stage, 1,2-propanediol, which has a lower boiling point than ethylene glycol, volatilizes preferentially, and the required amount may not be contained in the polyester.

[0018] Examples of catalysts used in the polycondensation reaction include known antimony compounds, aluminum compounds, germanium compounds, and titanium compounds. From an economical viewpoint, antimony compounds are most preferred, and from the viewpoint of antimony-free, aluminum compounds, germanium compounds, and titanium compounds are preferred.

[0019] The polyester resin used in the present invention may contain, as needed, a phosphorus compound as a stabilizer, an antioxidant, an ultraviolet absorber, a flame retardant, a fluorescent brightener, a matting agent, a plasticizer, an antifoaming agent, or other additives.

[0020] In the present invention, the polyester obtained by the above method may be further subjected to solid-state polymerization to obtain a polyester with an even higher molecular weight. The solid-state polymerization can be carried out by heat treatment under an inert gas atmosphere or under reduced pressure, although the apparatus and method are not particularly limited. The inert gas may be any gas inert to the polyester, such as nitrogen, helium, or carbon dioxide, although nitrogen is preferred for economic reasons. Regarding the reduced pressure, a lower pressure is advantageous because it shortens the time required for the solid-state polycondensation reaction. However, maintaining a pressure of 110 Pa or higher is preferred in order to retain components derived from 1,2-propanediol in the polyester.

[0021] The polyester resin used in the present invention can be produced by batch polymerization, semi-continuous polymerization, or continuous polymerization.

[0022] The polyester resin used in the present invention has an intrinsic viscosity of 0.6 to 0.7, preferably 0.62 to 0.68, and more preferably 0.63 to 0.66. If the intrinsic viscosity exceeds the upper limit, high-speed spinnability during fiber formation may be poor. Even if spinning is possible and the target degree of exhaustion is achieved, the surface quality of the resulting woven or knitted fibers may be reduced, such as the occurrence of dye spots or streaks in cylindrically knitted dyed fabrics and poor texture in woven or knitted fabrics, making them unsuitable for clothing. If the intrinsic viscosity is below the lower limit, yarn breakage may occur during spinning, resulting in poor productivity and low strength of the resulting fibers. Furthermore, even if spinning is possible and the target degree of exhaustion is achieved, the surface quality of the resulting woven or knitted fibers may be reduced, such as the occurrence of dye spots or streaks in cylindrically knitted dyed fabrics and poor texture in woven or knitted fabrics, making them unsuitable for clothing.

[0023] The polyester fiber of the present invention can be produced using common spinning equipment, and can be produced by any spinning method, such as a method of melt-spinning at low or medium speed followed by drawing, a direct spinning and drawing method at high speed, or a method of simultaneously or successively performing drawing and false twisting after spinning.

[0024] For example, in the spinning step of the polyester fiber production method of the present invention, a polyester resin is spun from a spinneret using a conventional melt spinning apparatus, and the cross-sectional shape and diameter of the resulting fiber can be arbitrarily set by changing the shape and size of the spinneret.

[0025] For example, a polyester resin is melt-kneaded using a single-screw extruder or a twin-screw extruder. The temperature during melt-kneading varies depending on the copolymerization amount of 1,2-propanediol and / or its ester-forming derivative. To achieve uniform and stable melt-kneading and stable spinnability and quality, the melt-kneading is carried out at a temperature range 20 to 60°C higher than the melting point of the polymer, and the molten polymer is introduced into a spinning head and discharged.

[0026] The polyester fiber melt-spun as described above is then cooled once to a temperature below its glass transition temperature, preferably to a temperature at least 10° C. lower than the glass transition temperature. The cooling method and cooling device in this case are not particularly limited as long as they can cool the spun polyester fiber to a temperature below its glass transition temperature, but it is preferable to provide a cooling air blowing device such as a cooling air blowing tube below the spinneret and blow cooling air onto the spun polyester fiber to cool it to a temperature below the glass transition temperature.

[0027] Next, as a method for obtaining drawn yarns with more efficient productivity and stable quality, the yarn is cooled to below the glass transition temperature after spinning, and then directly passed through a heating zone, specifically a device such as a tubular heating barrel, where it is subjected to a drawing heat treatment, oiled, and then wound up at a speed of 3500 to 5500 m / min to obtain a drawn yarn. The heating temperature in the heating step must be a temperature that makes drawing easy, i.e., a temperature above the glass transition temperature and below the melting point.

[0028] The oil is applied after the yarn has passed through the drawing process using a heating device. This reduces yarn breakage due to the oil. There are no restrictions on the oil as long as it is one that is normally used in polyester spinning. The oiling method may be either oiling nozzle oiling using a gear pump system or oiling roller oiling. However, as the spinning speed increases, the former method allows for more even and stable application of the oil to the yarn. There are no particular restrictions on the amount of oil applied, and it may be adjusted as appropriate as long as it is within a range that is suitable for the effect of suppressing yarn breakage and raw yarn fluffing and for the weaving and knitting process. Among these, it is preferable to set the amount of oil agent to 0.3 to 2.0 mass % since high quality polyester fibers can be smoothly obtained, and it is more preferable to set it to 0.3 to 1.0 mass %.

[0029] The polyester fiber of the present invention may contain, as additives, a matting agent such as titanium oxide, barium sulfate, or zinc sulfide, a heat stabilizer such as phosphoric acid or phosphorous acid, or a surface treatment agent such as a light stabilizer, an antioxidant, or silicon oxide.

[0030] The polyester fiber of the present invention has a chromaticity of b * The value is preferably 4.0 to 17.0, more preferably 4.5 to 16.0, and most preferably 5.0 to 15.0. * If the value exceeds the upper limit, the lightfastness after dyeing may decrease and the high-speed spinnability during spinning may be significantly poor. Even if fibers are obtained, the fibers may be of low quality, resulting in the occurrence of dyeing spots and streaks in cylindrically knitted dyed fabrics and poor texture in woven and knitted fabrics, making them unsuitable for clothing. * If the value is below the lower limit, the dyeability is sufficient but the high-speed spinnability may be poor.

[0031] The polyester fiber of the present invention preferably has a dyeability index K / S after dyeing of 19.0 or more. If K / S is below the lower limit, it cannot be said that sufficient dyeability has been obtained, and the fiber may be unsuitable for clothing. There is no particular restriction on the upper limit of K / S, but it may be 40 or less.

[0032] The polyester fiber of the present invention preferably has a light fastness of at least grade 4. If any of these is grade 3 or lower, it may be unsuitable for general clothing applications in terms of handling.

[0033] According to the present invention, it is possible to provide a polyester fiber that is excellent in dyeability and lightfastness, and that can provide stable quality and processability even when used with a direct spinning and drawing method or other general melt spinning methods. [Example]

[0034] The present invention will be described in detail below with reference to examples, but these examples are not intended to limit the scope of the present invention. The copolymerization amount of the 1,2-propanediol component, the physical properties of fineness, tensile strength and elongation, spinnability, lightfastness, color b * The value and dyeing concentration K / S were evaluated according to the following method.

[0035] <Amount of 1,2-propanediol copolymerized in fiber> The copolymerization amount of 1,2-propanediol in the fiber was measured by dissolving the fiber in deuterated trifluoroacetic acid solvent at a concentration of 3.0% (wt / vol) and measuring it at 400 MHz at 40 °C. 1 Measurement was performed using a H-NMR (JNM-ECZ 400S nuclear magnetic resonance spectrometer manufactured by JEOL Ltd.).

[0036] <Spinnability> The spinnability was evaluated according to the following criteria. ⊚: Spinnability is extremely good, with no breakage of yarns during 24-hour continuous spinning and absolutely no fluff or loops in the resulting polyester fiber. ○: Continuous spinning was carried out for 24 hours, and thread breakage during spinning occurred once or less. The obtained polyester fiber had no or only a small amount of fluff or loops, but the spinnability was generally good. △: After 24 hours of continuous spinning, thread breakage occurred up to three times during spinning, and spinnability was poor. ×: After 24 hours of continuous spinning, yarn breakage occurred more than three times during spinning, and spinnability was extremely poor.

[0037] <Fineness> The total fineness and single yarn fineness of the obtained fibers were measured in accordance with JIS L 1013 "Testing methods for chemical fiber filament yarns." The total fineness was measured as the fineness of the entire multifilament, and the single yarn fineness was calculated by dividing the measured total fineness value by the number of filaments.

[0038] <Tensile strength and elongation> In accordance with JIS L 1013, measurements were carried out using an Instron-type tensile testing machine (Instron 5500R) under conditions of a test length of 20 cm, an initial load of 0.1 g / dtex, and a tensile speed of 10 cm / min to determine strength and elongation, and the average values ​​of five or more points were used.

[0039] <Chromaticity(b * value)> chromaticity b *The values ​​were measured using a Konica Minolta spectrophotometer "CM-3700A" under the following conditions: specular reflection treatment: SCE, measurement diameter: LAV (25.4 mm), UV conditions: 100% Full, field of view: 2 degrees, and main light source: C light source. The measurement sample was prepared by forming a cylindrical knitted fabric from the obtained fibers using a circular knitting machine (28 gauge), scouring the fabric, and presetting it at 180°C.

[0040] <Stainability> The dyeing concentration (K / S) was calculated by measuring the reflectance R at the maximum absorption wavelength of the dyed sample knitted fabric and using the Kubelka-Munk equation shown below. Spectral reflectance measuring instrument: Spectrophotometer HITACHI C-2000S Color Analyzer K / S=(1-R) 2 / 2R The measurement samples were prepared by scouring the obtained tubular knitted fabric of the fiber, presetting it at 180°C, and dyeing it with the following dyes. (staining) ·Dye: Dianix Red UN-SE 1.0%owf Auxiliary agent: Disper TL: 1.0cc / l :ULTRA MT-N2: 1.0cc / l Bath ratio: 1 / 50 Dyeing temperature x time: 110℃ x 40 minutes (reduction cleaning) Sodium hydroxide: 1.0 g / L Sodium hydrosulfite: 1.0g / L Amylazine D: 1.0g / L Bath ratio: 1 / 50 Reduction cleaning temperature x time: 80°C x 20 minutes

[0041] <Lightfastness> Measurement was carried out in accordance with the measurement method of JIS L 0842, using a black panel at 63°C and the third exposure method. The measurement sample was a dyed knitted sample fabric, just like the sample for measuring the dye concentration.

[0042] Example 1 A glycol feedstock consisting of 45 parts by weight of ethylene glycol and a dicarboxylic acid feedstock consisting of 100 parts by weight of terephthalic acid were mixed to prepare a slurry with a molar ratio of glycol feedstock to dicarboxylic acid feedstock of 1.2:1. 1,2-Propanediol was added to this slurry at 520 ppm relative to the polymer to be obtained, and an esterification reaction was carried out under pressure (0.25 MPa absolute pressure) at 250°C until an esterification rate of 95% was achieved, yielding an oligomer. Next, 350 ppm of antimony trioxide was added as a catalyst and 10 ppm of phosphorous acid as a stabilizer, and the oligomer was polycondensed at 280°C under a reduced pressure of 120 Pa to yield a polymer with an intrinsic viscosity of 0.65 dL / g. The obtained polymer was melt-kneaded in an extruder and melt-spun using a spinneret with 24 holes at a spinning temperature of 290°C and a take-up speed of 3000 m / min to produce polyester filaments of 142 dtex / 24 filaments. The undrawn yarn was then brought into contact with a heated roller at 80°C and a heated plate at 120°C and drawn at a draw ratio of 1.7 to obtain a polyester fiber of 84 dtex / 24 filaments. The spinnability and the 1,2-propanediol content, fineness, strength, elongation, color, dyeability, and lightfastness of the obtained fibers are shown in Table 1. All of the fibers were successfully spun and had good dyeability and lightfastness.

[0043] Examples 2 to 4 The polyester fibers shown in Table 1 were obtained in the same manner as in Example 1, except that the amount of 1,2-propanediol added during polymerization was changed to adjust the copolymerization amount of the obtained fibers. All of the fibers could be spun well and had good physical properties such as dyeability and lightfastness.

[0044] Example 5 The fibers shown in Table 1 were obtained in the same manner as in Example 1, except for changing the spinning method. In the changed spinning method, a spinneret with 24 holes was used, and cooling air at a spinning temperature of 290°C and a humidity of 60% was blown onto the spun yarn at a speed of 0.5 m / sec to cool the yarn to 60°C or below. The yarn was then introduced into a tube heater (internal temperature 185°C) installed 1.2 m below the spinneret and stretched within the tube heater, followed by winding at a speed of 4,500 m / min to obtain a polyester fiber of 56 dtex / 24 filaments. The obtained fiber had good fiber properties.

[0045] (Comparative Examples 1 to 4) Polyester fibers of 84 dtex / 24 filaments shown in Table 1 were obtained in the same manner as in Example 1, except that the amount of 1,2-propanediol added during polymerization was changed to adjust the copolymerization amount of the obtained fibers.

[0046] [Table 1]

[0047] In Comparative Example 1, the co-weight of 1,2-propanediol was low, so not only was the spinnability poor, but the dyeability and lightfastness were also somewhat poor. In Comparative Examples 2 and 3, the co-weight of 1,2-propanediol was too high, so not only was the spinnability poor, but the lightfastness was also insufficient. In Comparative Example 4, no 1,2-propanediol was copolymerized, so the lightfastness was good, but the dyeability and spinnability were insufficient. [Industrial Applicability]

[0048] The polyester fiber of the present invention can be used in the form of a filament, but can also be used in the form of staple, spun yarn, woven or knitted fabric, dry-laid nonwoven fabric, or wet-laid nonwoven fabric. Specifically, it can be effectively used in a wide range of applications, such as men's and women's formal or casual fashion clothing, sportswear, uniforms, interior materials for automobiles and aircraft, curtains, carpets, etc. Furthermore, it can also be suitably used in plastic reinforcement (FRP), rubber reinforcement (FRR), tire cord, screen gauze, airbags, geogrids, battery components such as separators, liquid filters, air filters, paper substrates, wipers, artificial leather, synthetic leather, etc.

Claims

1. A polyester fiber made of a polyester resin, characterized in that the polyester resin is a copolymer of a dicarboxylic acid component and a glycol component, and that 95 to 99.87 mol % of the glycol component is ethylene glycol and / or an ester-forming derivative thereof, and 0.13 to 5 mol % of the glycol component is 1,2-propanediol and / or an ester-forming derivative thereof.

2. A fiber structure comprising at least a portion of the polyester fiber according to claim 1.

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