Polyester copolymer, polyester resin composition for melt spinning, polyester fiber production method, and polyester fiber

Abstract

This polyester copolymer (B) is used for obtaining a polyester resin composition for melt spinning, by mixing the polyester copolymer (B) with polyester (A). The polyester copolymer (B) contains polyalkylene glycol (B1) as a copolymer component thereof. The polyalkylene glycol (B1) has an average molecular weight in the range of 400-4,000. The content of the polyalkylene glycol (B1) in the polyester copolymer (B) is in the range of 15-60 mass%. The polyester copolymer (B) is used after mixed with the polyester (A) so as to be in the range of 0.5-15 parts by mass relative to the total 100 parts by mass of the polyester (A) and the polyester copolymer (B).

Description

Polyester copolymer, polyester resin composition for melt spinning, method for producing polyester fiber, and polyester fiber

[0001] The present disclosure relates to a polyester copolymer, a polyester resin composition for melt spinning, a method for producing a polyester fiber, and a polyester fiber.

[0002] Polyester fibers obtained by melt spinning modified polyethylene terephthalate are known, as described in Patent Document 1. The modified polyethylene terephthalate contains polyethylene glycol as a copolymerization component of the polyethylene terephthalate.

[0003] Japanese Patent Application Publication No. 04-041716

[0004] When dyeing polyester-based fibers, relaxing dyeing conditions such as the dyeing temperature is advantageous, for example, from the viewpoint of reducing energy consumption in the dyeing process. However, relaxing the dyeing conditions tends to reduce the fastness of the dyed polyester-based fibers. In other words, it is desired to suppress the decrease in fastness when relaxing the dyeing conditions.

[0005] The polyester-based copolymer that solves the above-mentioned problem is a (B) polyester-based copolymer used in an application in which a polyester-based resin composition for melt spinning is obtained by blending with an (A) polyester, and contains a (B1) polyalkylene glycol as a copolymerization component, the (B1) polyalkylene glycol having an average molecular weight in the range of 400 to 4,000, the content of the (B1) polyalkylene glycol in the (B) polyester-based copolymer being in the range of 15 to 60 mass%, and being used by blending with the (A) polyester so as to be in the range of 0.5 to 15 mass parts per 100 mass parts of the total of the (A) polyester and the (B) polyester-based copolymer.

[0006] A polyester-based resin composition for melt spinning that solves the above-mentioned problems contains (A) a polyester and (B) a polyester-based copolymer, and the (B) polyester-based copolymer contains (B1) a polyalkylene glycol as a copolymerization component, the average molecular weight of the (B1) polyalkylene glycol being in the range of 400 to 4,000, the content of the (B1) polyalkylene glycol in the (B) polyester-based copolymer being in the range of 15 to 60 mass%, and the content of the (B) polyester-based copolymer being in the range of 0.5 to 15 mass parts, relative to 100 mass parts of the total of the (A) polyester and the (B) polyester-based copolymer.

[0007] A method for producing a polyester fiber that solves the above-mentioned problems is a method for producing a polyester fiber comprising a step of melt-spinning a polyester resin composition for melt spinning, wherein the polyester resin composition for melt spinning contains (A) a polyester and (B) a polyester copolymer, and the (B) polyester copolymer contains (B1) a polyalkylene glycol as a copolymerization component, the average molecular weight of the (B1) polyalkylene glycol being in the range of 400 to 4,000, the content of the (B1) polyalkylene glycol in the (B) polyester copolymer being in the range of 15 to 60% by mass, and the content of the (B) polyester copolymer being in the range of 0.5 to 15 parts by mass, relative to 100 parts by mass of the total of the (A) polyester and the (B) polyester copolymer.

[0008] A polyester-based fiber that solves the above-mentioned problems contains (A) polyester and (B) polyester-based copolymer, and the (B) polyester-based copolymer contains (B1) polyalkylene glycol as a copolymerization component, the average molecular weight of the (B1) polyalkylene glycol is within the range of 400 to 4,000, the content of the (B1) polyalkylene glycol in the (B) polyester-based copolymer is within the range of 15 to 60% by mass, and the content of the (B) polyester-based copolymer is within the range of 0.5 to 15 parts by mass, relative to 100 parts by mass of the total of the (A) polyester and the (B) polyester-based copolymer.

[0009] The present disclosure exhibits an effect of making it possible to suppress a decrease in fastness of polyester-based fibers when dyeing conditions are relaxed.

[0010] DETAILED DESCRIPTION OF THE INVENTION The polyester resin composition for melt spinning contains (A) a polyester and (B) a polyester copolymer.

[0011] <(A) Polyester> The (A) polyester is the main component of the polyester-based resin composition for melt spinning. Examples of the (A) polyester include aromatic polyesters and aliphatic polyesters. Examples of the aromatic polyester include polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate. Examples of the aliphatic polyester include polylactic acid and polyglycolic acid.

[0012] The (A) polyester may be used alone or in combination with two or more other polyesters. From the viewpoint of further enhancing dyeability, the (A) polyester preferably includes at least one selected from polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate. The (A) polyester preferably has an intrinsic viscosity in the range of 0.3 to 1.7, more preferably 0.4 to 1.0.

[0013] <(B) Polyester-Based Copolymer> The (B) polyester-based copolymer contains (B1) polyalkylene glycol as a copolymerization component. The copolymerization component refers to a monomer unit that forms the (B) polyester-based copolymer. The (B1) polyalkylene glycol has an average molecular weight in the range of 400 to 4,000, preferably in the range of 400 to 3,000. When this average molecular weight is 400 or more, it is possible to suppress the occurrence of yarn breakage during the melt spinning process of the polyester-based resin composition for melt spinning. When this average molecular weight is 4,000 or less, it is possible to improve the dyeability of polyester fibers obtained from the polyester-based resin composition for melt spinning.

[0014] The average molecular weight of the polyalkylene glycol (B1) referred to in this specification is a number average molecular weight. The number average molecular weight of the polyalkylene glycol (B1) can be measured by GPC (gel permeation chromatography).

[0015] The content of the polyalkylene glycol (B1) in the polyester copolymer (B) is in the range of 15% by mass or more and 60% by mass or less, preferably 15% by mass or more and 50% by mass or less. When this content is 15% by mass or more, it is possible to improve dyeability. When this content is 60% by mass or less, it is possible to suppress the occurrence of thread breakage during the melt spinning process of the polyester resin composition for melt spinning.

[0016] The content of the polyalkylene glycol (B1) in the polyester copolymer (B) is １ It can be determined based on the peak intensity obtained by H-NMR spectrum analysis.

[0017] The (B1) polyalkylene glycol may be a homopolymer of alkylene glycol or a copolymer of alkylene glycol. Examples of alkylene glycol homopolymers include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. Examples of alkylene glycol copolymers include polyethylene glycol-polypropylene glycol copolymers (polyoxyethylene polyoxypropylene glycol), polyethylene glycol-polytetramethylene glycol copolymers, and the like.

[0018] The polyalkylene glycol (B1) preferably contains at least one selected from polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and a polyethylene glycol-polypropylene glycol copolymer.

[0019] The (B) polyester-based copolymer includes a (B2) second copolymerization component copolymerized with a (B1) polyalkylene glycol. The (B2) second copolymerization component includes, for example, at least one of an aromatic dicarboxylic acid and an ester-forming derivative of an aromatic dicarboxylic acid (B21) and a diol (B22). The (B) polyester-based copolymer can be obtained, for example, by reacting a (B1) polyalkylene glycol with a (B21) aromatic dicarboxylic acid and at least one of an ester-forming derivative of an aromatic dicarboxylic acid (B21), and a diol (B22). The (B) polyester-based copolymer may be synthesized in a single reaction or a multi-step reaction. For example, a polyester may be obtained by first reacting a (B21) aromatic dicarboxylic acid and at least one of an ester-forming derivative of an aromatic dicarboxylic acid with a diol (B22), and then reacting the polyester with a (B1) polyalkylene glycol.

[0020] Examples of aromatic dicarboxylic acids (B21) include terephthalic acid, isophthalic acid, phthalic acid, 5-sodium sulfoisophthalic acid, 5-lithium sulfoisophthalic acid, 5-(tetraalkyl)phosphonium sulfoisophthalic acid, 4,4'-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, etc. One or more aromatic dicarboxylic acids can be used.

[0021] Examples of the ester-forming derivatives of aromatic dicarboxylic acids (B21) include alkyl esters of aromatic dicarboxylic acids having 1 to 6 carbon atoms or hydroxyalkyl esters of aromatic dicarboxylic acids having 1 to 6 carbon atoms, such as dimethyl terephthalate, diethyl terephthalate, dipropyl terephthalate, dibutyl terephthalate, dihexyl terephthalate, bishydroxyethyl terephthalate, bishydroxypropyl terephthalate, bishydroxybutyl terephthalate, bishydroxyhexyl terephthalate, etc. One or more of the ester-forming derivatives of aromatic dicarboxylic acids can be used.

[0022] The aromatic dicarboxylic acid in at least one of the aromatic dicarboxylic acid and the ester-forming derivative of the aromatic dicarboxylic acid (B21) preferably contains at least one selected from terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid, from the viewpoint of improving spinnability and dyeability of the resulting polyester fiber.

[0023] The content of at least one of (B21) aromatic dicarboxylic acid and ester-forming derivative of aromatic dicarboxylic acid in the polyester copolymer (B) is preferably in the range of 10% by mass or more and 50% by mass or less, more preferably in the range of 20% by mass or more and 50% by mass or less. When this content is 10% by mass or more, it is possible to improve spinnability. When this content is 50% by mass or less, it is possible to improve spinnability.

[0024] (B22) Diols include aliphatic diols, alicyclic diols, and aromatic diols. Examples of aliphatic diols include ethylene glycol, 1,2-propanediol (propylene glycol), 1,3-propanediol (trimethylene glycol), 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, neopentyl glycol, and diethylene glycol. Examples of alicyclic diols include cyclopentanediol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, and 1,4-cyclohexanedimethanol. Examples of aromatic diols include naphthalenediol, bisphenol A, and resorcinol. As the diol (B22), polyalkylene glycols other than the polyalkylene glycol (B1) (such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol) can also be used. One or more types of diol (B22) can be used.

[0025] From the viewpoint of improving the spinnability and the dyeability of the resulting polyester fiber, the diol (B22) preferably contains at least one selected from ethylene glycol, propanediol, and butanediol.

[0026] The content of the diol (B22) in the polyester copolymer (B) is preferably in the range of 10% by mass or more and 50% by mass or less, more preferably in the range of 15% by mass or more and 40% by mass or less. When this content is 10% by mass or more, it is possible to improve spinnability. When this content is 50% by mass or less, it is possible to improve spinnability.

[0027] The (B) polyester copolymer may contain a trivalent or higher polyfunctional compound as a copolymerization component, as long as the polymer chain constituting the (B) polyester copolymer is substantially linear. Examples of trivalent or higher polyfunctional compounds include trimellitic acid, trimesic acid, pyromellitic acid, tricarballylic acid, and gallic acid. The (B) polyester copolymer may also contain a monofunctional compound as a copolymerization component. Examples of monofunctional compounds include benzoic acid, toluic acid, 1-naphthoic acid, 2-naphthoic acid, and o-benzoylbenzoic acid. The (B) polyester copolymer may also contain a hydroxycarboxylic acid as a copolymerization component. Examples of hydroxycarboxylic acids include lactic acid, glycolic acid, and hydroxybenzoic acid.

[0028] The (B) polyester copolymer can be synthesized by utilizing well-known esterification reactions and polymerization reactions (polycondensation reactions). The (B) polyester copolymer can also be synthesized by utilizing a transesterification reaction of an ester-forming derivative. The (B) polyester copolymer preferably has an intrinsic viscosity in the range of 0.1 to 1.7, from the viewpoint of improving spinnability and dyeability of the resulting polyester fiber.

[0029] The raw material composition for obtaining the polyester copolymer (B) contains the polyalkylene glycol (B1) and the second copolymerization component (B2) copolymerized with the polyalkylene glycol (B1).

[0030] The content of the polyalkylene glycol (B1) in the raw material composition is preferably 15% by mass or more and 60% by mass or less. The content of at least one of the aromatic dicarboxylic acid (B21) and the ester-forming derivative of the aromatic dicarboxylic acid in the raw material composition is preferably 10% by mass or more and 50% by mass or less. The content of the diol (B22) in the raw material composition is preferably 10% by mass or more and 50% by mass or less.

[0031] <Polyester-based resin composition for melt spinning and polyester-based fiber> The content of the polyester copolymer (B) in the polyester-based resin composition for melt spinning is in the range of 0.5 parts by mass or more and 15 parts by mass or less, and preferably in the range of 1 part by mass or more and 10 parts by mass or less, relative to 100 parts by mass of the total of the polyester (A) and the polyester copolymer (B). When this content is 0.5 parts by mass or more, it is possible to improve dyeability. When this content is 15 parts by mass or less, it is possible to suppress the occurrence of thread breakage in the process of melt-spinning the polyester-based resin composition for melt spinning.

[0032] From the viewpoint of improving spinnability, the content of the polyester (A) in the polyester-based resin composition for melt spinning is, for example, preferably in the range of 50% by mass or more and 99.5% by mass or less, more preferably in the range of 60% by mass or more and 99.0% by mass or less, even more preferably in the range of 70% by mass or more and 98.0% by mass or less, and most preferably in the range of 80% by mass or more and 97.0% by mass or less.

[0033] The content of the polyester copolymer (B) and the content of the polyester (A) in the polyester fiber are the same as those in the polyester resin composition for melt spinning.

[0034] The polyester resin composition for melt spinning may also contain, for example, a heat stabilizer, an antioxidant, an ultraviolet absorber, an infrared absorber, a fluorescent brightener, a conductive agent, an antistatic agent, a compatibilizer, a plasticizer, a release agent, an antibacterial agent, a nucleating agent, a matting agent, an antifoaming agent, a preservative, a gelling agent, a latex, a filler, a fragrance, and the like.

[0035] The polyester-based resin composition for melt spinning can be prepared by mixing the (A) polyester and the (B) polyester-based copolymer so that the (B) polyester-based copolymer is in the above-mentioned content range. The polyester-based resin composition for melt spinning can also be prepared by previously preparing a mixture of the (A) polyester and the (B) polyester-based copolymer and then diluting the mixture with the (A) polyester. The polyester-based resin composition for melt spinning can also be prepared by previously preparing a mixture of the (A) polyester and the (B) polyester-based copolymer and then further mixing the (B) polyester-based copolymer into the mixture.

[0036] The polyester (A) and the polyester copolymer (B) can be mixed by a known method, for example, a tumbler, a V-type blender, a super mixer, a Banbury mixer, a kneading roll, or a single-screw or twin-screw extruder.

[0037] The fineness of the polyester fiber single fiber is preferably in the range of 0.01 dtex or more and 300 dtex or less, and more preferably in the range of 0.05 dtex or more and 250 dtex or less, from the viewpoint of improving the spinnability and the dyeability of the resulting polyester fiber.

[0038] Polyester fibers are used in dyeing applications. Polyester fibers can be dyed using, for example, disperse dyes. Examples of disperse dyes include benzene azo dyes, heterocyclic azo dyes, disazo dyes, anthraquinone dyes, quinoline dyes, nitro dyes, coumarin dyes, methine dyes, and amino ketone dyes.

[0039] Examples of dyeing methods that can be used include textile printing, continuous dyeing, and dip dyeing. Examples of dip dyeing methods include jet dyeing, cheese dyeing, beam dyeing, Obermeyer dyeing, and high-pressure jet dyeing.

[0040] Polyester-based fibers can be used in the form of yarn, knitted fabric, woven fabric, nonwoven fabric, etc. Examples of uses of polyester-based fibers include apparel, interior design, and industrial materials.

[0041] <Method for producing polyester fiber> The method for producing polyester fiber includes a step of melt-spinning the polyester resin composition for melt spinning. A known method can be used for the melt-spinning step. The method for producing polyester fiber preferably includes a step of drying the polyester resin composition for melt spinning as a pre-step of the melt-spinning step. In this case, it is possible to suppress a decrease in molecular weight due to hydrolysis of the polyester resin and to suppress foaming caused by moisture in the melt-spinning step. The step of drying the polyester resin composition for melt spinning may be a step of drying a mixture of (A) polyester and (B) polyester copolymer, or a step of drying (A) polyester and (B) polyester copolymer separately.

[0042] The water content of the (A) polyester and the (B) polyester copolymer is preferably 0 ppm or more and 300 ppm or less, more preferably 0 ppm or more and 100 ppm or less, and even more preferably 0 ppm or more and 50 ppm or less.

[0043] The melt spinning step may be carried out continuously with the step of preparing the polyester-based resin composition for melt spinning, or may be carried out using pellets prepared in advance by solidifying the polyester-based resin composition for melt spinning.

[0044] The polyester resin composition for melt spinning can be melted using a melt extruder, such as a pressure melter type melt extruder or a single-screw or twin-screw extruder type melt extruder.

[0045] In the melt spinning step, the polyester resin composition for melt spinning is extruded in a fibrous form from the spinneret of a melt spinning machine. In the melt spinning step, the fibrous polyester resin composition for melt spinning extruded from the spinneret is solidified by cooling, thereby obtaining a polyester fiber. The obtained polyester fiber is wound up after, for example, a yarn oil is applied to the polyester fiber.

[0046] The spinning temperature in the melt spinning step can be selected depending on the melting points, heat resistance, etc. of the (A) polyester and (B) polyester-based copolymer. The spinning temperature is, for example, preferably in the range of 190°C or higher and 320°C or lower, more preferably in the range of 240°C or higher and 310°C or lower, even more preferably in the range of 250°C or higher and 310°C or lower, and most preferably in the range of 260°C or higher and 300°C or lower. When the spinning temperature is 190°C or higher, the occurrence of thread breakage can be suppressed. When the spinning temperature is 320°C or lower, the thermal decomposition of the polyester-based resin composition for melt spinning can be suppressed.

[0047] The spinning speed in the melt spinning step can be selected depending on the composition of the polyester resin composition for melt spinning, the spinning temperature, etc. The spinning speed is selected as follows depending on, for example, a one-step method in which the melt spinning step and the drawing step are performed continuously, or a two-step method in which the raw yarn is drawn or false-twisted in a separate step after the melt spinning step. The one-step method is also called the FDY (Fully Drawn Yarn) method. The two-step method is also called the POY (Partially Oriented Yarn) / DTY (Draw Textured Yarn) method.

[0048] In the one-step method, the spinning speed is set, for example, by the first take-off roller and the second take-off roller. The speed of the first take-off roller is preferably in the range of 50 m / min to 5,000 m / min, more preferably in the range of 80 m / min to 4,500 m / min. The speed of the second take-off roller is preferably in the range of 60 m / min to 6,000 m / min, more preferably in the range of 100 m / min to 5,500 m / min.

[0049] In the two-step method, the spinning speed is preferably in the range of 500 m / min or more and 6000 m / min or less. The spinning speed is more preferably 1000 m / min or more, and even more preferably 1500 m / min or more. The spinning speed is more preferably 4500 m / min or less, and even more preferably 4000 m / min or less.

[0050] In the drawing step in the one-step or two-step method, either a one-stage drawing method or a multi-stage drawing method of two or more stages can be used. The running yarn in the drawing step is heated by a direct or indirect heating method. Examples of heating methods include heating elements such as a heating roller, a heat pin, or a hot plate, a liquid bath using warm water or hot water, a gas bath using hot air or steam, and laser irradiation. One heating method or a combination of two or more heating methods can be used. For example, from the viewpoint of easy temperature control, at least one of contact with a heating element and immersion in a liquid bath is preferred as the heating method.

[0051] The drawing temperature in the drawing step can be selected depending on the extrapolated melting initiation temperatures of the (A) polyester and (B) polyester-based copolymer, the strength and elongation of the fiber after drawing, etc. In the case of a one-step method, the drawing temperature in the drawing step is preferably in the range of 50°C or higher and 150°C or lower, more preferably in the range of 60°C or higher and 145°C or lower, and even more preferably in the range of 70°C or higher and 140°C or lower. When the drawing temperature in the one-step method is 50°C or higher, for example, the quality of the yarn can be improved. When the drawing temperature in the one-step method is 150°C or lower, for example, the drawing step can be carried out stably. In the drawing step, heat setting may be carried out at a temperature range of 60°C or higher and 150°C or lower, as necessary.

[0052] In the case of a two-step method, the drawing temperature in the drawing step is preferably in the range of 100°C or higher and 230°C or lower, more preferably in the range of 120°C or higher and 210°C or lower, and even more preferably in the range of 160°C or higher and 200°C or lower. When the drawing temperature in the two-step method is 100°C or higher, the running yarn is stabilized, and the occurrence of yarn breakage can be further suppressed. When the drawing temperature in the two-step method is 230°C or lower, the occurrence of yarn breakage can be further suppressed.

[0053] The draw ratio in the drawing step can be selected depending on the elongation of the fiber before drawing, the strength and elongation of the fiber after drawing, etc. From the viewpoint of further improving fastness and dyeability, the draw ratio is preferably in the range of 1.02 to 7.0 times, more preferably in the range of 1.2 to 6.5 times, and even more preferably in the range of 1.5 to 6.0 times.

[0054] The drawing speed in the drawing step can be selected depending on the one-step method, two-step method, etc. The drawing speed in the one-step method corresponds to the speed of the second take-up roller, so explanation will be omitted. The drawing speed in the two-step method is preferably in the range of 30 m / min or more and 1000 m / min or less, more preferably in the range of 50 m / min or more and 900 m / min or less, and even more preferably in the range of 100 m / min or more and 800 m / min or less. When the drawing speed is equal to or higher than the lower limit, the running yarn is stabilized, thereby preventing yarn breakage. When the drawing speed is equal to or lower than the upper limit, preventing yarn breakage. The take-up speed is not particularly limited, and is preferably in the range of 500 m / min or more and 6000 m / min or less.

[0055] <Actions and Effects of the Present Embodiment> Next, the actions and effects of the present embodiment will be described. (1) The (B) polyester-based copolymer is used in an application in which it is mixed with the (A) polyester to obtain a polyester-based resin composition for melt spinning. The (B) polyester-based copolymer contains a (B1) polyalkylene glycol as a copolymerization component. The average molecular weight of the (B1) polyalkylene glycol is in the range of 400 to 4,000. The content of the (B1) polyalkylene glycol in the (B) polyester-based copolymer is in the range of 15 to 60% by mass. The (B) polyester-based copolymer is mixed with the (A) polyester so as to be in the range of 0.5 to 15 parts by mass per 100 parts by mass of the total of the (A) polyester and the (B) polyester-based copolymer.

[0056] According to this configuration, it is possible to suppress a decrease in fastness of polyester fibers obtained from the polyester resin composition for melt spinning when dyeing conditions are relaxed. Generally, polyester fibers are dyed under high temperature conditions of 130°C or higher and 135°C or lower, and high pressure. The polyester fibers of this embodiment can improve dyeability when dyed, for example, under low temperature conditions of 100°C and normal pressure. Even when dyeing conditions are relaxed in this way, it is possible to suppress a decrease in fastness, such as washing fastness.

[0057] (2) The polyalkylene glycol (B1) preferably contains at least one selected from polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and polyethylene glycol-polypropylene glycol copolymer, which can improve dyeability, for example.

[0058] <Examples> Next, examples and comparative examples will be described. (Example 1) <Synthesis of (B) Polyester-Based Copolymer> 21 parts by mass of (B1) polyalkylene glycol, 45 parts by mass of (B21) terephthalic acid, 34 parts by mass of (B22) ethylene glycol, and 0.01 parts by mass of an esterification catalyst were charged into a reaction vessel. The raw materials in the reaction vessel were gradually heated from 150°C to 240°C, and an esterification reaction was carried out over 3 hours while distilling off water. Next, 0.01 parts by mass of a polycondensation catalyst was added to the reaction vessel, and prepolymerization was carried out over 50 minutes. Subsequently, the pressure in the reaction vessel was gradually reduced, and finally, a polymerization reaction was carried out under conditions of 0.1 kPa, 275°C, and 160 minutes, thereby obtaining (B) polyester-based copolymer.

[0059] The obtained polyester copolymer (B) was in the form of chips and had an intrinsic viscosity of 0.6. The contents of polyalkylene glycol (B1) and ethylene glycol (B22) in the obtained polyester copolymer (B) were １ It was determined from the peak intensity of the H-NMR spectrum.

[0060] １ The measurement conditions for H-NMR spectrum are as follows. Nuclear magnetic resonance apparatus: JEOL Ltd., product name: ECZ-500R Deuterated solvent: deuterated trifluoroacetic acid Number of accumulations: 16 Sample concentration: 0.01 g of measurement sample / 0.7 mL of deuterated solvent The content of (B1) polyalkylene glycol was determined by setting the integral value of the chemical shift (8.4 ppm) derived from terephthalic acid to 4.0 and calculating the relative value to the integral value of the chemical shift of (B1) polyalkylene glycol. The chemical shift of ethylene glycol is 5.1 ppm, and the chemical shift of polyethylene glycol (PEG) is 4.2 ppm. The chemical shift of polypropylene glycol (PPG) is 1.5 ppm. The chemical shift of polytetramethylene glycol (PTMG) is 2.0 ppm. The chemical shifts of polyoxyethylene polyoxypropylene glycol (POEPOPG) are 1.5 ppm and 2.0 ppm.

[0061] ​The content of (B1) polyalkylene glycol (hereinafter referred to as "PAG") in the (B) polyester-based copolymer was 20% by mass, as shown in the "(B1) PAG" and "Content [% by mass]" columns in Table 1. The content of (B21) terephthalic acid in the (B) polyester-based copolymer was 46% by mass. The content of (B22) ethylene glycol in the (B) polyester-based copolymer was 34% by mass.

[0062] The average molecular weight of (B1) polyalkylene glycol in (B) polyester copolymer was measured as follows. 1 g of polyester copolymer and 3 g of sodium hydroxide were added to a mixed solution of 5 ml of water and 10 ml of ethanol, and the mixture was heated at 120°C for 20 hours to cause alkaline decomposition. The alkaline decomposition product was neutralized, filtered to remove the neutralized salt, and the filtrate was evaporated to dryness. The dried product was extracted with chloroform, and the chloroform was removed to obtain a polyalkylene glycol extract.

[0063] The number average molecular weight (Mn) of the extract was measured according to the following method. 2 mg of the extract was added to 2 mL of tetrahydrofuran and mixed. The tetrahydrofuran-soluble portion of the resulting mixture was analyzed by gel permeation chromatography (GPC), and the Mn of the polyalkylene glycol was determined in terms of polyethylene glycol. The GPC measurement conditions were as follows:

[0064] Measurement device: HLC-8320GPC (product name, manufactured by Tosoh Corporation) Detection device: RI detector (detector attached to HLC-8320GPC) Mobile phase: tetrahydrofuran Column: Two TSKgel superMultipore HZ-M columns (manufactured by Tosoh Corporation) and one TSKgel superMultipore HZ-H column (manufactured by Tosoh Corporation) connected in series were used.

[0065] Sample injector and column temperature: 40° C. RI detector temperature: 35° C. Sample injection amount: 5 μL Flow rate: 0.35 mL / min Measurement time: 20 min Details of the raw materials are as follows:

[0066] (B1) PAG: polyethylene glycol (PEG), average molecular weight: 1540, manufactured by NOF Corporation, trade name: PEG #1540; (B21) aromatic dicarboxylic acid: terephthalic acid, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.; (B22) diol: ethylene glycol, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.; Esterification catalyst: titanium tetra-normal butoxide; Polycondensation catalyst: titanium tetra-normal butoxide. The intrinsic viscosity was measured in accordance with JIS K7367-1:2002, "Method for determining the viscosity of a diluted polymer solution using a plastic capillary viscometer." More specifically, (B) polyester copolymer was dissolved in a mixed solvent of phenol and 1,1,2,2-tetrachloroethane to a concentration of 0.4 g / dl, and the measurement was performed at 30°C. The volume ratio of phenol to 1,1,2,2-tetrachloroethane in the mixed solvent was 1:1.

[0067] <Preparation of polyester-based resin composition for melt spinning> Polyethylene terephthalate (manufactured by Unitika Ltd., product name: MA-6102-K, intrinsic viscosity: 0.6) was prepared as the (A) polyester. The (B) polyester-based copolymer obtained in the synthesis step was dried at 140°C under a nitrogen gas flow of 100 mL / min for 8 hours. As shown in Table 1, 95 parts by mass of the (A) polyester and 5 parts by mass of the (B) polyester-based copolymer were melt-kneaded using an extrusion kneader to obtain a polyester-based resin composition for melt spinning.

[0068] The obtained polyester resin composition for melt spinning was supplied to a spinneret having 48 spinnerets using a gear pump. The filaments extruded from the spinneret were stretched by the speed difference between a first take-up roller and a second take-up roller provided downstream of the first take-up roller.

[0069] The conditions for the spinning process were as follows: Spinning temperature: 280°C Cooling temperature: 20°C Cooling air velocity: 1.8 m / s Speed ​​of first take-off roller (drawing speed): 500 m / min Temperature of first take-off roller (drawing temperature): 100°C Speed ​​of second take-off roller (drawing speed): 2500 m / min Temperature of second take-off roller (drawing temperature): 115°C Draw ratio: 5.0 times Take-up speed: 2470 m / min Through the above spinning process, raw silk (FDY) of 80 denier (approximately 88.8 dtex) / 48 filaments was obtained.

[0070] (Examples 2 and 3) As shown in Table 1, in Examples 2 and 3, the spinning process was carried out in the same manner as in Example 1, except that the content of the polyester copolymer (B) in the polyester resin composition for melt spinning was changed.

[0071] Example 4 In Example 4, 52 parts by mass of PAG (B1), 27 parts by mass of terephthalic acid (B21), 21 parts by mass of ethylene glycol (B22), and 0.01 parts by mass of an esterification catalyst were charged into a reaction vessel, and then the synthesis and spinning steps of polyester copolymer (B) were carried out in the same manner as in Example 1.

[0072] The content of PAG (B1) in the polyester-based copolymer (B) was 50% by mass, as shown in the "PAG (B1)" and "Content [% by mass]" columns in Table 1. The content of terephthalic acid (B21) in the polyester-based copolymer (B) was 28% by mass. The content of ethylene glycol (B22) in the polyester-based copolymer (B) was 22% by mass.

[0073] (Examples 5 to 9) As shown in Table 2, in Examples 5 to 9, the synthesis and spinning steps of the polyester copolymer (B) were carried out in the same manner as in Example 1, except that the PAG (B1) used in the synthesis of the polyester copolymer (B) was changed.

[0074] Details of the (B1) PAG used in Examples 5 to 9 are as follows: (B1) PAG of Example 5: polyethylene glycol (PEG), average molecular weight: 600, manufactured by Sanyo Chemical Industries, Ltd., trade name: PEG-600. (B1) PAG of Example 6: polyethylene glycol (PEG), average molecular weight: 2000, manufactured by Sanyo Chemical Industries, Ltd., trade name: PEG-2000. (B1) PAG of Example 7: polypropylene glycol (PPG), average molecular weight: 2000, manufactured by ADEKA Corporation, trade name: ADEKA Polyether P-2000. (B1) PAG of Example 8: polytetramethylene ether glycol (PTMG), average molecular weight: 2000, manufactured by Mitsubishi Chemical Corporation, trade name: PTMG2000. (B1) PAG of Example 9: polyoxyethylene polyoxypropylene glycol (POEPOPG), average molecular weight: 2000, manufactured by ADEKA Corporation, trade name: ADEKA Pluronic L-44. The content of PAG (B1) in the polyester-based copolymer (B) was 20% by mass, as shown in the "PAG (B1)" and "Content [% by mass]" columns in Table 2. The content of terephthalic acid (B21) in the polyester-based copolymer (B) was 46% by mass. The content of ethylene glycol (B22) in the polyester-based copolymer (B) was 34% by mass.

[0075] Example 10 As shown in Table 2, in the synthesis of the polyester copolymer (B) in Example 10, the following two types of PAG (B1) were used.

[0076] First (B1) PAG: polyethylene glycol (PEG), average molecular weight: 3400, manufactured by Sanyo Chemical Industries, Ltd., product name: PEG-4000S Second (B1) PAG: polypropylene glycol (PPG), average molecular weight: 2000, manufactured by ADEKA Corporation, product name: ADEKA POLYETHER P-2000 In the synthesis of the (B) polyester-based copolymer in Example 10, 25 parts by mass of the first (B1) PAG, 5 parts by mass of the second (B1) PAG, 40 parts by mass of (B21) terephthalic acid, 30 parts by mass of (B22) ethylene glycol, and 0.01 parts by mass of the esterification catalyst were charged into a reaction vessel, and then the synthesis and spinning steps of the (B) polyester-based copolymer were carried out in the same manner as in Example 1.

[0077] The content of the (B1) PAG in the (B) polyester-based copolymer was 30% by mass in total of the two types, as shown in the "(B1) PAG" and "Content [% by mass]" columns in Table 2. The content of the (B21) terephthalic acid in the (B) polyester-based copolymer was 40% by mass. The content of the (B22) ethylene glycol in the (B) polyester-based copolymer was 30% by mass.

[0078] (Example 11) As shown in Table 2, in Example 11, the synthesis and spinning steps of the polyester copolymer (B) were carried out in the same manner as in Example 1, except that the PAG (B1) used in the synthesis of the polyester copolymer (B) was changed.

[0079] (B1) PAG in Example 11: polyethylene glycol (PEG), average molecular weight: 3400, manufactured by Sanyo Chemical Industries, Ltd., product name: PEG-4000S. The content of (B1) PAG in the (B) polyester-based copolymer was 20% by mass, as shown in the "(B1) PAG" and "Content [% by mass]" columns in Table 2. The content of (B21) terephthalic acid in the (B) polyester-based copolymer was 46% by mass. The content of (B22) ethylene glycol in the (B) polyester-based copolymer was 34% by mass.

[0080] Comparative Example 1 As shown in Table 3, in Comparative Example 1, polyethylene glycol (PEG, average molecular weight: 400, manufactured by Sanyo Chemical Industries, Ltd., product name: PEG-400) was used as PAG (B1). In addition, in the synthesis of polyester-based copolymer (B) in Comparative Example 1, 21 parts by mass of PAG (B1), 45 parts by mass of terephthalic acid (B21), 34 parts by mass of ethylene glycol (B22), and 0.01 parts by mass of an esterification catalyst were charged into a reaction vessel, and then the synthesis and spinning steps of polyester-based copolymer (B) were carried out in the same manner as in Example 1.

[0081] Comparative Example 2 As shown in Table 3, in Comparative Example 2, polyethylene glycol (PEG, average molecular weight: 1000, manufactured by Sanyo Chemical Industries, Ltd., product name: PEG-1000) was used as PAG (B1). In addition, in the synthesis of polyester-based copolymer (B) in Comparative Example 2, 6 parts by mass of PAG (B1), 53 parts by mass of terephthalic acid (B21), 41 parts by mass of ethylene glycol (B22), and 0.01 parts by mass of an esterification catalyst were charged into a reaction vessel, and then the synthesis and spinning steps of polyester-based copolymer (B) were carried out in the same manner as in Example 1.

[0082] Comparative Examples 3 and 4 In Comparative Examples 3 and 4, the synthesis and spinning steps of polyester copolymer (B) were carried out in the same manner as in Example 1, except for the changes shown in Table 3.

[0083] Comparative Example 5 As shown in Table 3, in Comparative Example 5, the same PAG (B1) as in Example 1 was used. In addition, in the synthesis of the polyester-based copolymer (B) in Comparative Example 5, 10 parts by mass of the PAG (B1), 51 parts by mass of terephthalic acid (B21), 39 parts by mass of ethylene glycol (B22), and 0.01 parts by mass of an esterification catalyst were charged into a reaction vessel, and then the synthesis and spinning steps of the polyester-based copolymer (B) were carried out in the same manner as in Example 1.

[0084] Comparative Example 6 As shown in Table 3, in Comparative Example 6, the same PAG (B1) as in Example 1 was used. In addition, in the synthesis of the polyester-based copolymer (B) in Comparative Example 6, 65 parts by mass of PAG (B1), 20 parts by mass of terephthalic acid (B21), 15 parts by mass of ethylene glycol (B22), and 0.01 parts by mass of an esterification catalyst were charged into a reaction vessel, and then the synthesis and spinning steps of the polyester-based copolymer (B) were carried out in the same manner as in Example 1.

[0085] Comparative Example 7 In Comparative Example 7, the spinning process was carried out in the same manner as in Example 1, except that only (A) polyester was used.

[0086] (Spinnability) After continuous spinning for 1 hour using the spinning process, the occurrence of thread breakage was confirmed. Cases where no thread breakage occurred were judged as excellent, cases where spinning was possible but thread breakage occurred within 30 minutes to less than 1 hour were judged as good, and cases where thread breakage occurred within 30 minutes were judged as poor. In the "Spinnability" column of Tables 1 to 3, excellent cases are indicated by "a," good cases by "b," and poor cases by "c."

[0087] (Dyeing Ability) The raw silk obtained in each Example and Comparative Example was cylindrically knitted at 20 gauge using a single-mouth test cylindrical knitting machine (manufactured by Eiko Sangyo Co., Ltd., product name: model NCR-E) to prepare a test piece for dyeing.

[0088] The obtained test piece was placed in a refining bath so that the bath ratio was 1:15. The refining bath was heated from 40 ° C. to 80 ° C. at a temperature increase rate of 3 ° C. / min, and then held at 80 ° C. for 20 minutes. Next, the refining bath was cooled to 70 ° C., and the test piece was removed from the refining bath. The removed test piece was then washed with water and dehydrated and dried to obtain a refined test piece.

[0089] Next, the test pieces were placed in a dye bath. In Examples 1 to 11 and Comparative Examples 1 to 6, the test pieces were dyed under the following <Dyeing Condition 1>.

[0090] <Dyeing Condition 1> In dyeing condition 1, the dyeing temperature was set to a low temperature. In dyeing condition 1, the dye bath was heated from 60°C to 100°C at a temperature increase rate of 2°C / min, and then held at 100°C for 60 minutes. Next, the dye bath was cooled to 70°C, and the test piece was taken out of the dye bath.

[0091] In Comparative Example 7, the test piece was dyed under the following <Dyeing Condition 2>. <Dyeing Condition 2> In dyeing condition 2, the dyeing temperature was set to a high temperature. In dyeing condition 2, the dye bath was heated from 60°C to 130°C at a temperature increase rate of 2°C / min, and then held at 130°C for 30 minutes. Next, the temperature was lowered to 70°C, and the test piece was then removed from the dye bath.

[0092] Each test piece dyed under the above-mentioned <Dyeing Condition 1> and <Dyeing Condition 2> was subjected to reduction cleaning using a reduction cleaning bath under conditions of 80°C, 15 minutes, and a bath ratio of 1:15. After reduction cleaning, the test piece was washed with water, dehydrated, and dried to obtain a dyed test piece.

[0093] The compositions of the scouring bath, dyeing bath, and reduction cleaning bath are shown in Table 4. For the dyed test pieces, the K / S values ​​were determined every 10 nm from 400 to 700 nm using a spectrophotometer (manufactured by Konica Minolta Sensing Inc., product name: CM-3600d), and then the integrated values ​​of these K / S values ​​were determined. The integrated values ​​for the test pieces of each Example and Comparative Example other than Comparative Example 7 were determined when the integrated value for the test piece of Comparative Example 7 was set to 100. This integrated value was used as the dye exhaustion rate for the test pieces of each Example and Comparative Example other than Comparative Example 7. The results are shown in Tables 1 to 3.

[0094] The higher the dyeing rate, the darker the dyeing, i.e., the better the dyeing property. Regarding dyeing property, a dyeing rate of 60 or more was judged to be pass. In the "Judgment Result" column of Tables 1 to 3, pass cases are indicated by "a" and fail cases by "c".

[0095] (Washing Fastness) Washing fastness tests were conducted in accordance with the A-5 method of JIS L0844:2011, and the grade of washing fastness was determined using the staining gray scale (JIS L0805:2005). The results are shown in Tables 1 to 3. The higher the washing fastness grade, the better the fastness. Regarding washing fastness, washing fastness of grade 3 or higher was judged as passing. In the "Judgment Result" column of Tables 1 to 3, passing cases are indicated by "a" and failing cases by "c."

[0096]

[0097]

[0098]

[0099]

[0100] As shown in Tables 1 and 2, Examples 1 to 11 achieved pass results in both dyeing ability and washing fastness. On the other hand, as shown in Table 3, Comparative Example 1 did not contain (A) polyester, resulting in poor spinnability. Comparative Example 2 had a (B2) PAG content of less than 15% by mass, and did not contain (A) polyester. Comparative Example 2 achieved good spinnability and a pass result in dyeing ability, but failed in washing fastness. Comparative Example 3 achieved a fail result in dyeing ability because the content of the (B) polyester-based polymer was less than 0.5 parts by mass relative to 100 parts by mass of the total of the (A) polyester and the (B) polyester-based copolymer. Comparative Example 4 achieved a poor result in spinnability because the content of the (B) polyester-based polymer was more than 15 parts by mass relative to 100 parts by mass of the total of the (A) polyester and the (B) polyester-based copolymer. Comparative Example 5 achieved a fail result in dyeing ability because the content of the (B1) PAG was less than 15% by mass. In Comparative Example 6, the content of (B1) PAG exceeded 60% by mass, resulting in poor spinnability.

Claims

1. A (B) polyester-based copolymer used for obtaining a polyester-based resin composition for melt spinning by blending with an (A) polyester, comprising a (B1) polyalkylene glycol as a copolymerization component, the (B1) polyalkylene glycol having an average molecular weight in the range of 400 to 4,000, the (B1) polyalkylene glycol having a content in the (B) polyester-based copolymer in the range of 15 to 60% by mass, and the (B1) polyalkylene glycol being blended with the (A) polyester in an amount in the range of 0.5 to 15 parts by mass per 100 parts by mass of the total of the (A) polyester and the (B) polyester-based copolymer.

2. The polyester copolymer according to claim 1, wherein the polyalkylene glycol (B1) comprises at least one member selected from the group consisting of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and polyethylene glycol-polypropylene glycol copolymer.

3. The polyester copolymer according to claim 1, wherein the copolymerization components further comprise (B21) at least one of an aromatic dicarboxylic acid and an ester-forming derivative of an aromatic dicarboxylic acid, and (B22) a diol.

4. (A) Polyester is a polyester copolymer containing at least one selected from polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate.

5. A polyester-based resin composition for melt spinning comprising: (A) a polyester; and (B) a polyester-based copolymer; the (B) polyester-based copolymer contains (B1) a polyalkylene glycol as a copolymerization component; the average molecular weight of the (B1) polyalkylene glycol is in the range of 400 to 4,000; the content of the (B1) polyalkylene glycol in the (B) polyester-based copolymer is in the range of 15 to 60 mass%; and the content of the (B) polyester-based copolymer is in the range of 0.5 to 15 mass parts per 100 mass parts of the total of the (A) polyester and the (B) polyester-based copolymer.

6. A method for producing a polyester fiber, comprising a step of melt spinning a polyester resin composition for melt spinning, wherein the polyester resin composition for melt spinning contains (A) a polyester and (B) a polyester copolymer, the (B) polyester copolymer contains (B1) a polyalkylene glycol as a copolymerization component, the average molecular weight of the (B1) polyalkylene glycol is in the range of 400 to 4,000, the content of the (B1) polyalkylene glycol in the (B) polyester copolymer is in the range of 15 to 60 mass%, and the content of the (B) polyester copolymer is in the range of 0.5 to 15 mass parts per 100 mass parts of the total of the (A) polyester and the (B) polyester copolymer.

7. A polyester-based fiber comprising (A) a polyester and (B) a polyester-based copolymer, wherein the (B) polyester-based copolymer contains (B1) a polyalkylene glycol as a copolymerization component, the average molecular weight of the (B1) polyalkylene glycol being within the range of 400 or more and 4,000 or less, the content of the (B1) polyalkylene glycol in the (B) polyester-based copolymer being within the range of 15% by mass or more and 60% by mass or less, and the content of the (B) polyester-based copolymer being within the range of 0.5 parts by mass or more and 15 parts by mass or less per 100 parts by mass of the total of the (A) polyester and the (B) polyester-based copolymer.

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