JP2023184004A - polyester fiber - Google Patents

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

The present invention relates to polyester fibers having excellent dyeability and light fastness.

Polyester fibers are used in various fields, mainly for clothing, due to their mechanical properties, dyeability, and handling properties. However, polyester fibers generally have poor dyeability due to their dense fiber structure, and there is a demand for polyester fibers with better dyeability. Therefore, many methods have been studied to improve dyeability by modifying the dicarboxylic acid component or glycol component of polyester resin.
For example, Patent Document 1 (International Publication No. WO 2011/068195) discloses a room-temperature dyeable polyester fiber obtained by modifying a dicarboxylic acid component. Furthermore, Patent Document 2 (Japanese Unexamined Patent Publication No. 2009-209145) and Patent Document 3 (International Publication WO 2013/035559) disclose that modification is achieved by modifying or containing a component derived from 1,2-propanediol, which is a glycol component. Polyester fibers obtained from recycled polyester resins are disclosed.

International publication WO2011/068195 JP2009-209145A International publication WO2013/035559

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, and therefore has insufficient spinnability in some cases. In addition, the polytrimethylene terephthalate fiber obtained from 1,2-propanediol and terephthalic acid described in Patent Document 2 has excellent dyeability and fluidity compared to polyethylene terephthalate fiber, but has poor light fastness. There was a problem. Further, due to the low melting point and low heat resistance, spinnability was sometimes insufficient. The polyester fiber described in Patent Document 3 has improved heat resistance by limiting the amount of 1,2-propanediol-derived components contained in the polyester to 15 to 500 ppm, reduces staining of the die, and increases production efficiency. However, there was a problem with light fastness.

Therefore, an object of the present invention is to solve the above-mentioned problems and to provide a polyester fiber having excellent dyeability and light fastness.

The present inventors conducted extensive studies to achieve the above object, and as a result, they arrived at the present invention. That is, the present invention provides the following preferred embodiments.
[1] A polyester fiber composed of a polyester resin, wherein the polyester resin is a copolymer composed of a dicarboxylic acid component and a glycol component, and 95 to 99.87 mol% of the glycol component is ethylene glycol and/or 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 containing at least a portion of the polyester fiber according to [1] above.

According to the present invention, polyester fibers having excellent dyeability and light fastness can be provided.

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, and 95 to 99.87 mol% of the glycol component is ethylene glycol and/or its ester-forming derivative. Of these, 0.13 to 5 mol% is 1,2-propanediol and/or its ester-forming derivative.

95 to 99.87 mol% of the glycol component of the polyester resin used in the present invention is ethylene glycol and/or its ester-forming derivative. If the amount of ethylene glycol and/or its ester-forming derivative is less than the above lower limit, not only will the heat resistance and spinnability deteriorate, but also the light fastness will decrease, and the excellent fiber physical properties originally possessed by polyester fibers will be diminished. will be greatly damaged. Furthermore, when the amount of ethylene glycol and/or its ester-forming derivative exceeds the above upper limit, the dyeability decreases. The content of ethylene glycol and/or its ester-forming derivative is preferably 97.5 to 99.85 mol%, more preferably 98 to 99.83 mol%.

Of the glycol component of the polyester resin used in the present invention, 0.13 to 5 mol% is 1,2-propanediol and/or its ester-forming derivative. If the amount of 1,2-propanediol and/or its ester-forming derivative exceeds the above upper limit, the heat resistance of the polyester will deteriorate, the spinnability will deteriorate, and the quality of the textile product will deteriorate, as well as the resulting Since the melting point of the fiber is lower, consumption performance such as ironing resistance becomes a problem. Moreover, when the obtained fibers are dyed, light fastness becomes poor. If the amount of 1,2-propanediol and/or its ester-forming derivative is less than the above lower limit, the heat resistance of the polyester will deteriorate, the spinnability will deteriorate, and the quality of the textile product will deteriorate, as well as insufficient No staining properties are obtained. The content of 1,2-propanediol and/or its ester-forming derivative is preferably 0.14 to 4 mol%, more preferably 0.15 to 3 mol%.

The reason why dyeability improves without decreasing light fastness is not clearly elucidated at present, but 1,2-propane is incorporated into the polymer molecular skeleton within a range where the polymer glass transition temperature does not decrease significantly. It is presumed that this is because the methyl group of the diol forms an appropriate amount of space between molecules, increasing the number of dyeing sites in the amorphous region. In addition, the reason for the high light fastness is presumed to be that unlike ether bonds, which absorb light energy and cause the molecular skeleton to cleave, there is no generation of oxygen radicals that would have a negative effect on dye fastness. Ru.

The content of 1,2-propanediol and/or its ester-forming derivative as a copolymer component is the content of 1,2-propanediol and/or its ester-forming derivative detected when the polyester resin is decomposed and analyzed. This is determined from the total amount of 1,2-propanediol derived from 1,2-propanediol copolymerized in the polymer chain and/or its ester-forming derivatives. , represents the total amount including 1,2-propanediol and/or its ester-forming derivative mixed among the polymers.

The dicarboxylic acid component which is a monomer of the polyester resin used in the present invention is preferably a dicarboxylic acid and/or an ester-forming derivative thereof, such as terephthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, diphenyl-4 , 4'-dicarboxylic acid, and ester-forming derivatives thereof. The ester-forming derivatives referred to in the present invention include lower alkyl esters, acid anhydrides, and acyl chlorides of these dicarboxylic acids, and methyl esters, ethyl esters, hydroxyethyl esters, and the like are preferably used. 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.

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

In addition, as a copolymerization component of polyester containing ethylene glycol as a diol component, not only 1,2-propanediol but also 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1, Diol components such as 6-hexanediol, polyoxyalkylene glycol (polyethylene glycol, etc.) with a molecular weight of 500 to 20,000, diethylene glycol, 2-methyl-1,3-propanediol, bisphenol A-ethylene oxide adduct, cyclohexanedimethanol, etc. Copolymerization may be carried out 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 derivative.

The dicarboxylic acid component and glycol component used in the present invention may be derived from petroleum or biomass. Since ethylene glycol derived from biomass often contains 1,2-propanediol, it is also possible to use ethylene glycol derived from biomass resources whose content has been adjusted through purification.
Further, the raw material for the polyester fiber used in the present invention described above may be a chemically recycled monomer or oligomer.

The polyester resin used in the present invention is manufactured by a conventional method. For example, during the direct esterification reaction, the reaction temperature is preferably 250° C. or lower and the pressure is preferably 1.2×100,000 Pa or higher. In the further polycondensation reaction, it is preferable to keep the reaction temperature at 280° C. or lower and the pressure at a pressure of 110 Pa or higher, as the polymerization time becomes shorter as the pressure decreases. At higher temperatures and lower pressures in each reaction step, 1,2-propanediol, which has a boiling point lower than that of ethylene glycol, volatilizes preferentially and may not be contained in the required amount in the polyester.

Catalysts used in the polycondensation reaction include known antimony compounds, aluminum compounds, germanium compounds, and titanium compounds. Economically, antimony compounds are most preferred, and from the viewpoint of antimony-free properties, aluminum compounds, germanium compounds, and titanium compounds are preferred.

The polyester resin used in the present invention requires stabilizers such as phosphorus compounds, antioxidants, ultraviolet absorbers, flame retardants, optical brighteners, matting agents, plasticizers or antifoaming agents, or other additives. They may be blended accordingly.

Further, in the present invention, in order to obtain a polyester with a higher molecular weight, the polyester obtained by the above method may be further subjected to solid phase polymerization. Solid phase polymerization is carried out by heat treatment in an inert gas atmosphere or under reduced pressure, although the apparatus and method are not particularly limited. Any inert gas may be used as long as it is inert to the polyester, and examples thereof include nitrogen, helium, carbon dioxide, etc., but nitrogen is preferably used from the viewpoint of economy. In addition, as for the reduced pressure, it is advantageous to use a more reduced pressure condition because it can shorten the time required for the solid phase polycondensation reaction. It is preferable for it to remain.

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

The polyester resin used in the present invention has an intrinsic viscosity of 0.6 to 0.7, preferably 0.62 to 0.68, more preferably 0.63 to 0.66. If the intrinsic viscosity exceeds the above upper limit, high-speed spinnability during fiberization may become poor. In addition, even if spinning is possible and the target dyeing rate is obtained, the surface quality of the resulting woven or knitted fibers may be affected, such as the occurrence of dyeing spots or streaks in tube-knitted dyed fabrics or poor texture of woven or knitted fabrics. may be undesirable for use in clothing. Moreover, if the intrinsic viscosity is below the above-mentioned lower limit, yarn breakage may occur easily during spinning, resulting in poor productivity, and the strength of the obtained fibers may also be reduced. Furthermore, even if spinning is possible and the target dyeing rate is obtained, the surface quality of the resulting woven or knitted fibers may be affected, such as the occurrence of dyeing spots or streaks in tube-knitted dyed fabrics or poor texture of the woven or knitted fabrics. may be undesirable for use in clothing.

The polyester fiber of the present invention can be produced using general spinning equipment, and can be produced by melt spinning at low or medium speeds and then drawing, by direct spinning and drawing at high speed, by simultaneously or sequentially drawing and false twisting after spinning. It can be manufactured by any method of spinning yarn, such as a method of spinning yarn.

For example, in the spinning step in the method for producing polyester fibers of the present invention, polyester resin is spun from a spinneret using an ordinary melt spinning device. Furthermore, the cross-sectional shape and diameter of the resulting fibers can be arbitrarily set depending on the shape and size of the cap.

For example, polyester resin is melt-kneaded using a single-screw extruder or a twin-screw extruder. The temperature during melt-kneading varies depending on the amount of copolymerization of 1,2-propanediol and/or its ester-forming derivative, but in order to stably melt-knead without unevenness and obtain stable thread-spinning properties and quality, Melt kneading is carried out at a temperature range of 20 to 60° C. higher than the melting point of the polymer, and the molten polymer is introduced into a spinning head and discharged.

Then, the polyester fibers melt-spun as described above are once cooled to a temperature below its glass transition temperature, preferably at least 10° C. lower than its glass transition temperature. In this case, the cooling method and cooling device are not particularly limited, as long as they can cool the spun polyester fiber to below its glass transition temperature, but there are no particular restrictions on the cooling method or device. It is preferable to provide a cooling air blowing device to blow cooling air onto the spun polyester fibers to cool them to below the glass transition temperature.

Next, as a method to obtain drawn yarn with more efficient productivity and stable quality, after spinning, the yarn is once cooled to below the glass transition temperature, and then directly heated in a heating zone, specifically, in a tube. A drawn yarn can be obtained by running the yarn through a device such as a mold heating tube to heat it for stretching, and after oiling, winding it up at a speed of 3,500 to 5,500 m/min. The heating temperature in the heating step needs to be a temperature that facilitates stretching, that is, a temperature that is higher than the glass transition temperature and lower than the melting point.

The oil agent is applied after passing through the stretching process using a heating device. This reduces the number of yarn breaks caused by the oil agent. There are no restrictions on the oil as long as it is normally used for spinning polyester. The oiling method may be either oiling nozzle oiling using a gear pump method or oiling roller oiling. However, as the spinning speed increases, the former method allows for stable oil adhesion without unevenness on the yarn. There is no particular restriction on the amount of oil applied, and it may be adjusted as appropriate as long as it is within a range suitable for the effect of suppressing yarn breakage and yarn fluff and for the process of weaving and knitting.
Among these, it is preferable that the amount of oil applied is 0.3 to 2.0% by mass, since high quality polyester fibers can be obtained smoothly, and it is more preferable that the amount of oil applied is 0.3 to 1.0% by mass. preferable.

The polyester fibers of the present invention each contain a matting agent such as titanium oxide, barium sulfate, or zinc sulfide, a heat stabilizer such as phosphoric acid or phosphorous acid, or a light stabilizer, an antioxidant, or a surface agent such as silicon oxide. A processing agent or the like may be included as an additive.

The polyester fiber of the present invention preferably has a chromaticity b ^* value of 4.0 to 17.0, more preferably 4.5 to 16.0, and most preferably 5.0 to 15.0. If the b ^* value exceeds the above upper limit, the light fastness after dyeing may decrease and the high-speed spinnability during spinning may become extremely poor. Furthermore, even when fibers are obtained, they are of low quality and may be undesirable for use in clothing, such as the occurrence of dyeing spots and streaks in tube-knit dyed fabrics and poor texture of woven or knitted fabrics. Furthermore, if the b ^* value is below the above lower limit, the dyeability is sufficient but the high-speed spinnability may be poor.

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

The polyester fiber of the present invention preferably has a light fastness of grade 4 or higher. If any of them is grade 3 or lower, it may not be suitable for use in general clothing from the viewpoint of handleability.

According to the present invention, it is possible to provide a polyester fiber that has excellent dyeing properties and light fastness, and can provide stable quality and processability even in direct spinning and drawing techniques or other general melt spinning techniques.

EXAMPLES Hereinafter, the present invention will be explained in detail with reference to Examples, but these are not intended to limit the present invention. In addition, the amount of copolymerization of the 1,2-propanediol component of the fiber obtained in the present invention, physical properties such as fineness, tensile strength and elongation, spinnability, light fastness, chromaticity b ^* value, dyeing concentration K /S was evaluated according to the following method.

<Copolymerization amount of 1,2-propanediol in fiber>
The copolymerized amount of 1,2-propanediol in the fibers was determined by dissolving the fibers in a deuterated trifluoroacetic acid solvent at a concentration of 3.0% (wt/vol) and performing 400MHz ¹ H-NMR (Japan) at 40°C. The measurement was performed using a nuclear magnetic resonance device manufactured by Denshi (JNM-ECZ 400S).

<Spinning properties>
Spinnability was evaluated according to the following criteria.
◎: Continuous spinning was carried out for 24 hours, and no yarn breakage occurred during spinning, and the resulting polyester fibers had extremely good spinnability, with no fuzz or loops occurring at all.
○: Continuous spinning was carried out for 24 hours, and yarn breakage occurred less than once during spinning, and the resulting polyester fiber did not have any fluff or loops, or although a few fluffs and loops occurred. The properties are almost good.
Δ: Continuous spinning was performed for 24 hours, and yarn breakage occurred up to three times during spinning, resulting in poor spinnability.
×: Continuous spinning was performed for 24 hours, and yarn breakage occurred more than three times during spinning, and the spinnability was extremely poor.

<Fineness>
The total fineness and single yarn fineness of the obtained fibers were measured in accordance with JIS L 1013 "Chemical fiber filament yarn testing method". The total fineness was measured as the fineness of the entire multifilament, and the single yarn fineness was calculated as the value obtained by dividing the measured total fineness by the number of filaments.

<Tensile strength and elongation>
In accordance with JIS L 1013, the strength and The elongation was determined and the average value of 5 or more points was adopted.

<Chromaticity (b ^* value)>
Chromaticity b ^* Values are measured using a spectrophotometer "CM-3700A" manufactured by Konica Minolta, specular reflection treatment: SCE, measurement diameter: LAV (25.4 mm), UV conditions: 100% Full, field of view: 2 degrees , Main light source: Measured under the conditions of C light source.
The sample for measurement used was one in which a tubular knitted fabric was made from the obtained fibers using a circular knitting machine (28 gauge), refined, and preset at 180°C.

<Dyeability>
The dyeing density (K/S) was determined by measuring the reflectance R at the maximum absorption wavelength of the sample knitted fabric after dyeing, and using the Kubelka-Munk equation shown below.
Spectral reflectance measuring instrument: Spectrophotometer HITACHI
C-2000S Color Analyzer
K/S=(1-R) ² /2R
As samples for measurement, the obtained tubular knitted fabrics of fibers were scoured, preset at 180° C., and dyed 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: 1.0g/L
Sodium hydrosulfite: 1.0g/L
Amyrazine D: 1.0g/L
Bath ratio: 1/50
Reduction cleaning temperature x time: 80℃ x 20 minutes

<Lightfastness>
Measurement was carried out in accordance with the measurement method of JIS L 0842, using a black panel at 63° C. and using the third exposure method.
In addition, the sample knitted fabric after dyeing was used as the sample for measurement, just like the sample for measurement of dyeing concentration.

(Example 1)
A glycol raw material consisting of 45 parts by weight of ethylene glycol and a dicarboxylic acid raw material consisting of 100 parts by weight of terephthalic acid were mixed to prepare a slurry in which the molar ratio of glycol raw material to dicarboxylic acid raw material was 1.2:1. To this slurry, 1,2-propanediol was added to the polymer at a concentration of 520 ppm, and the esterification reaction was carried out at 250°C under pressure (absolute pressure 0.25 MPa) until the esterification rate reached 95%. A low polymer was obtained. Next, 350 ppm of antimony trioxide as a catalyst and 10 ppm of phosphorous acid as a stabilizer were added, and the low polymer was polycondensed at 280° C. under a reduced pressure of 120 Pa to obtain a polymer with an intrinsic viscosity of 0.65 dl/g.
The obtained polymer was melt-kneaded in an extruder, melt-spun using a spinneret with 24 holes at a spinning temperature of 290°C and a winding speed of 3000 m/min, and spun with polyester filaments of 142 dtex/24 filaments. Thereafter, this undrawn yarn was 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 times to obtain a polyester fiber of 84 dtex/24 filaments.
Table 1 shows the spinnability, 1,2-propanediol content, fineness, strength, elongation, chromaticity, dyeability, and light fastness of the obtained fibers. All of them could be spun well and had good dyeability and light fastness.

(Examples 2 to 4)
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 and the amount of copolymerization of the resulting fibers was adjusted. All of them could be spun well and had good physical properties such as dyeability and light fastness.

(Example 5)
The fibers shown in Table 1 were obtained in the same manner as in Example 1 except that the spinning method was changed. The modified spinning method uses a spinneret with 24 holes to blow cooling air at a spinning temperature of 290°C, a temperature of 25°C, and a humidity of 60% onto the spun yarn at a speed of 0.5 m/sec to form 60 yarns. ℃ or less, the filament was introduced into a tube heater (inner temperature 185℃) installed 1.2m below the spinneret, drawn within the tube heater, and wound at a speed of 4500m/min to form a 56dtex/24 filament. of polyester fibers were obtained. The obtained fiber had good fiber properties.

(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 and the amount of copolymerization of the obtained fiber was adjusted. .

In Comparative Example 1, since the co-weight of 1,2-propanediol was low, not only the spinnability was poor, but also the dyeability and light fastness were slightly poor. In Comparative Examples 2 and 3, since the co-weight of 1,2-propanediol was too large, not only the spinnability was poor, but also the light fastness was insufficient. In Comparative Example 4, since 1,2-propanediol was not copolymerized, the light fastness was good, but the dyeability and spinnability were insufficient.

The polyester fibers of the present invention can be used in the form of filaments, but also in the form of staples, spun yarns, woven and knitted fabrics, dry nonwoven fabrics, and wet nonwoven fabrics. Specifically, it can be effectively used in a wide variety of applications, such as formal or casual fashion clothing for men and women, sports, uniforms, interior materials for automobiles and aircraft, curtains and carpets, etc. In addition, we offer plastic reinforcing materials (FRP), rubber reinforcing materials (FRR), tire cords, screen gauze, air bags, geogrids, battery structural products such as separators, liquid filters, air filters, paper base materials, wipers, It is also suitably used for artificial leather, synthetic leather, etc.

Claims (2)

A polyester fiber composed of a polyester resin, wherein the polyester resin is a copolymer composed of a dicarboxylic acid component and a glycol component, and 95 to 99.87 mol% of the glycol component is ethylene glycol and/or its ester. A polyester fiber, which is a forming derivative, and is characterized in that 0.13 to 5 mol% is 1,2-propanediol and/or its ester forming derivative. A fiber structure comprising at least a portion of the polyester fiber according to claim 1.