Method for producing synthetic fibers, method for producing drawn false-twisted yarn, and method for producing a dilution of a synthetic fiber treatment agent

Abstract

The present invention provides a method for producing synthetic fibers that can reduce yarn breakage and improve the quality of synthetic fibers, a method for producing drawn false-twisted yarns, a diluted solution of a synthetic fiber treating agent, and a synthetic fiber treating agent. [Solution] The present invention is a method for producing synthetic fibers, comprising a cooling step in which cooling air is blown onto a running yarn spun from a spinneret in a direction approximately perpendicular and / or approximately parallel to the running direction, and an application step in which a diluted solution of a synthetic fiber treatment agent is applied to the cooled running yarn, wherein the diluted solution of the synthetic fiber treatment agent contains 5% by mass or more and 20% by mass or less of the synthetic fiber treatment agent and 80% by mass or more and 95% by mass or less of the volatile diluent, and the diluted solution has a light transmittance of 90% or more at a wavelength of 750 nm at 25°C and a cloud point of 30°C or higher.

Description

[Technical Field]

[0001] The present invention relates to a method for producing synthetic fibers, a method for producing drawn false-twisted yarns, and Diluted solution of synthetic fiber treatment agent Manufacturing method Regarding. [Background technology]

[0002] Generally, in the spinning process of synthetic fibers, etc., a synthetic fiber treatment agent is applied to the surface of the synthetic fiber in order to reduce friction and damage to the fiber such as thread breakage. Conventionally, synthetic fiber treatment agents disclosed in Patent Documents 1 to 3 are known.

[0003] Patent Document 1 discloses a diluted solution of a synthetic fiber treatment agent that essentially contains a lubricant, a nonionic surfactant, and a low-viscosity diluent, and also contains at least one selected from organic sulfonates, organic phosphates, oil film strengtheners, ethylene oxide adducts of organic amines, and antioxidants.

[0004] Patent Document 2 discloses a synthetic fiber treatment agent containing a smoothing agent, a nonionic surfactant, and an ionic surfactant, in which the smoothing agent is a compound having a specific ester structure, and the nonionic surfactant contains an alkylene oxide adduct of an aliphatic alcohol having 4 to 24 carbon atoms and a branched chain structure.

[0005] Patent Document 3 discloses a fiber treatment agent containing a specific organic phosphoric acid compound, in which the weight ratio of inorganic phosphoric acid is 3% by weight or less. The synthetic fiber spinning process usually includes a cooling step in which cooling air is blown onto the running filament spun from a spinneret. To produce high-quality filament yarn, uniform cooling during the spinning step and application of an appropriate synthetic fiber treatment agent are important.

[0006] Draw textured yarn (DTY) has also been known, in which long fibers such as polyester and nylon fibers are twisted, followed by heating, cooling, and then untwisting in succession to impart bulk and stretchability to the fibers. The method for producing draw textured yarn involves first obtaining a partially oriented yarn (POY) by, for example, high-speed spinning, followed by cooling and applying a fiber treatment agent for false twisting. The partially oriented yarn then undergoes a drawing and false twisting process to produce a draw textured yarn. Among the spinning processes, particularly in the POY-DTY process, uniform cooling and the application of an appropriate fiber treatment agent for false twisting are important in the production of high-quality draw textured yarn.

[0007] A conventionally known fiber treatment agent for false twisting is disclosed in Patent Document 4. Patent Document 4 discloses a fiber treatment agent for false twisting that contains, as a nonionic surfactant, an ionic surfactant such as a polyoxyalkylene alkyl ether or an alkyl sulfonate. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent Publication No. 2021-155881 [Patent Document 2] Patent Publication No. 2021-195643 [Patent Document 3] Japanese Patent Application Publication No. 2020-073741 [Patent Document 4] International Publication No. 2015 / 008591 Summary of the Invention [Problem to be solved by the invention]

[0009] However, conventionally, thread breakage has occurred in processes after the application of the synthetic fiber treatment agent, and there has been a demand for further improvement in the quality of the resulting synthetic fibers. [Means for solving the problem]

[0010] As a result of research aimed at solving the above-mentioned problems, the inventors have focused on a diluted solution of a treatment agent for synthetic fibers having a predetermined concentration, and have found that a configuration in which the light transmittance and cloud point of such a diluted solution are specified within a predetermined range is preferable.

[0011] Various aspects for solving the above problems will be described. The method for producing a synthetic fiber of the first aspect comprises blowing cooling air against the running direction of the running yarn spun from the spinneret. Abbreviation a cooling step of spraying a running yarn with water in a direction parallel to the running yarn; and an application step of applying a diluted solution of a synthetic fiber treatment agent to the cooled running yarn, wherein the diluted solution of the synthetic fiber treatment agent contains a synthetic fiber treatment agent and a volatile diluent; the synthetic fiber treatment agent contains a nonionic surfactant and an ionic surfactant, and the volatile diluent contains 90% by mass or more of water; When the total content of the synthetic fiber treatment agent and the volatile diluent is 100% by mass, the synthetic fiber treatment agent is 5% by mass or more and 20% by mass or less, and the volatile diluent is 80% by mass or more and 95% by mass or less, the diluted solution has a light transmittance of 90% or more at a wavelength of 750 nm at 25°C, and the cloud point of the diluted solution is 30°C or higher. Diluent is selected It is characterized by:

[0012] A second aspect is the method for producing a synthetic fiber according to the first aspect, wherein the dilution liquid has a cloud point of 35° C. or higher. A third aspect is the method for producing synthetic fibers according to the first or second aspect, wherein the dilution liquid has a cloud point of 40° C. or higher.

[0013] A fourth aspect is the method for producing a synthetic fiber according to any one of the first to third aspects, wherein the volatile diluent contains water, and the electrical conductivity of the water is 0 μs / cm or more and less than 50 μs / cm.

[0014] status Mr. 5 is aspect 1~ 4 In the synthetic fiber manufacturing method according to any one of the above aspects, the cooling air is moreover With respect to the running direction of the running yarn Approximately vertical direction It is sprayed onto Aspects 6 is aspect 1~ 5 In the method for producing a synthetic fiber according to any one of the above aspects, the synthetic fiber is a partially oriented yarn.

[0015] Aspects 7 The method for producing the drawn false-twisted yarn is as follows: 6 The present invention is characterized in that it uses a partially oriented yarn obtained by the synthetic fiber manufacturing method described in 1. Aspects 8 Diluted solution of synthetic fiber treatment agent Manufacturing method teeth, The present invention is applied to a spinning apparatus including a cooling device that blows cooling air onto a running yarn spun from a spinneret in a direction substantially parallel to the running direction, and an application device that applies a diluted solution of a synthetic fiber treatment agent to the cooled running yarn, A diluted solution of a synthetic fiber treatment agent containing a synthetic fiber treatment agent and a volatile diluent Manufacturing method And, the synthetic fiber treatment agent contains a nonionic surfactant and an ionic surfactant, and the volatile diluent contains 90% by mass or more of water; When the total content of the synthetic fiber treatment agent and the volatile diluent is 100% by mass, the synthetic fiber treatment agent is 5% by mass or more and 20% by mass or less, and the volatile diluent is 80% by mass or more and 95% by mass or less, the diluted solution has a light transmittance of 90% or more at a wavelength of 750 nm at 25°C, and the cloud point of the diluted solution is 30°C or higher. Diluent is selected It is characterized by:

[0016] Aspects 9 is the aspect 8 A diluted solution of the synthetic fiber treatment agent described in Manufacturing method The cloud point of the diluted solution is 35°C or higher. Aspects 10 is the aspect 8 or 9 A diluted solution of the synthetic fiber treatment agent described in Manufacturing method The cloud point of the diluted solution is 40°C or higher.

[0017] Aspects 11 is the aspect 8 ~ 10 A diluted solution of the synthetic fiber treatment agent according to any one of the above aspects. Manufacturing method The volatile diluent contains water, and the electrical conductivity of the water is 0 μs / cm or more and less than 50 μs / cm.

[0018] Aspects 12 is the aspect Any one of 8 to 11 aspects A diluted solution of the synthetic fiber treatment agent described in Manufacturing method In the above, the cooling device moreover The cooling air is blown in the running direction of the running yarn. Approximately vertical direction It is sprayed onto 。

[0019] A thirteenth aspect of the present invention relates to the method for producing a diluted solution of a treatment agent for synthetic fibers according to any one of aspects eight to twelve, wherein the application device is disposed above the ventilation path after the cooling air is blown onto the running yarn. [Effects of the Invention]

[0020] According to the present invention, it is possible to reduce yarn breakage and improve the quality of synthetic fibers. DETAILED DESCRIPTION OF THE INVENTION

[0021] One embodiment of the synthetic fiber manufacturing method of the present invention will be described below. The synthetic fiber manufacturing method of this embodiment includes a cooling step in which cooling air is blown onto the running yarn spun from the spinneret in a direction approximately perpendicular and / or approximately parallel to the running direction, and an application step in which a diluted solution (hereinafter referred to as "diluent") of a synthetic fiber treatment agent (hereinafter referred to as "treatment agent") is applied to the cooled running yarn. The synthetic fiber manufacturing method is carried out using a spinning apparatus equipped with a cooling device that blows cooling air onto the running yarn spun from the spinneret, and an application device that applies the diluted solution to the cooled running yarn. A commercially available spinning apparatus can be used as the spinning apparatus.

[0022] The purpose of producing synthetic fibers is not particularly limited, and examples include spinning and drawing applications (FDY) in the production of flat yarn, and spinning-false-twisting applications (POY-DTY) in the production of false-twisted yarn (DTY).

[0023] (synthetic fiber) Specific examples of synthetic fibers are not particularly limited and are appropriately selected depending on the purpose, use, etc. Examples include (1) polyester fibers such as polyethylene terephthalate (PET), polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polylactic acid, and composite fibers containing these polyester resins, (2) polyamide fibers such as nylon 6 and nylon 66, (3) polyacrylic fibers such as polyacrylic and modacrylic, and (4) polyolefin fibers such as polyethylene and polypropylene.

[0024] (cooling process) The cooling step is carried out using a cooling device that blows cooling air onto the running yarn spun from the spinneret in a direction approximately perpendicular and / or approximately parallel to the running direction. In the present invention, the cooling is carried out using a cooling device that blows air in a direction substantially parallel to the traveling direction.

[0025] The device for blowing air in a direction approximately perpendicular to the running direction of the yarn is a device that has one or more cooling air blowing means provided downstream of the yarn spinning section, and supplies cooling air from a lateral direction to the spun yarn, i.e., in a direction approximately perpendicular to the running direction, thereby cooling the spun yarn.

[0026] An example of a cooling device that blows air in a direction substantially perpendicular to the running direction of the yarn is a cross-flow cooling device. The cooling device that blows cooling air onto the running yarn spun from the spinneret in a direction substantially parallel to the running direction may be a cooling device in which the cooling air outlet is arranged to be oriented substantially parallel to the running direction of the yarn. Alternatively, the cooling device may be provided with a straightening plate or a guide plate so that the cooling air blown in a direction substantially perpendicular to the running yarn is directed substantially parallel to the running direction.

[0027] Examples of cooling devices that blow cooling air onto the running yarn spun from the spinneret in a direction approximately parallel to the running direction include circular quenchers (Circular Quench, Radial Quench). Examples of circular quenchers include CIQ (Circular Inflow Quench) and iQC (Intelligent Quench) from TMT Machinery. Examples include the EvoQuench Chamber and EvoQuench from Oerlikon Barmag. The annular cooling device is configured such that an annular cooling cylinder is placed below the spinneret of the spin pack so that the axis of the cylinder and the running direction of the yarn are approximately parallel, and the spun yarn passes through the inside of the cooling cylinder. The inner circumferential surface of the cooling cylinder is formed with blowing sections that blow cooling air inward from all sides, for example, around the group of filaments running in the axial direction of the cooling cylinder. With this configuration, the running yarn spun from the spinneret can be cooled uniformly from all sides.

[0028] For example, an annular extension tube serving as a guide plate may be connected to the downstream opening of the cooling tube of the above-described circular cooling device. This configuration reduces lateral stress, which can cause the running yarn to sway and the yarn to swell in the downwind direction, compared to a configuration in which cooling air is blown only in a direction substantially perpendicular to the running direction of the running yarn. Furthermore, a cooling method in which air is blown in a direction substantially parallel to the running yarn provides a long cooling area for the running yarn, improving heat exchange efficiency and uniform cooling of the filaments. If the cooling device has a cooling tube, it is preferable to close the opening on the spinneret side upstream of the running yarn to prevent cooling of the spinneret and improve cooling efficiency within the extension tube.

[0029] (Diluted solution) The diluent used in the application step contains a treatment agent and a volatile diluent. The light transmittance of the diluted solution at a wavelength of 750 nm at 25°C is 90% or more, preferably 91% or more. By specifying this range, the quality of the resulting synthetic fiber can be particularly improved. The light transmittance can be measured using a commercially available spectrophotometer with a quartz cell having a cell length (optical path length) of 10 mm.

[0030] The cloud point of the diluted solution is not less than 30° C., preferably not less than 35° C., and more preferably not less than 40° C. By specifying the cloud point within this range, yarn breakage can be reduced particularly in the subsequent steps. To measure the cloud point, first pour the diluted solution into a test tube to a height of approximately 40 mm, then place a thermometer inside and heat the tube while stirring thoroughly with the thermometer to a temperature approximately 2-3°C higher than the temperature at which clouding occurs. Next, air-cool the solution while stirring thoroughly again, and measure the temperature at which it becomes clear as the cloud point. Alternatively, if the diluted solution is already cloudy at room temperature, cool it while stirring thoroughly until it becomes clear, then gradually heat it while stirring thoroughly again to the temperature at which clouding occurs. Next, gradually cool it while stirring, and measure the temperature at which it becomes clear as the cloud point.

[0031] The cloud point and light transmittance of the diluted solution vary depending on the ratio of the treatment agent to the volatile diluent, the ratio of water in the volatile diluent, etc., as will be described later. In the present invention, a dilution liquid is selected that has a light transmittance of 90% or more at a wavelength of 750 nm at 25°C and a cloud point of 30°C or higher.

[0032] (Treatment agent) Known treatment agents can be used. Examples include spinning and drawing oils, spinning and false twisting oils, etc. Treatment agents generally contain a smoothing agent, a nonionic surfactant, an ionic surfactant, etc. In the present invention, the treatment agent contains a nonionic surfactant and an ionic surfactant.

[0033] The lubricating agent may, for example, be an ester, a mineral oil, or a polyolefin. The ester is not particularly limited, and examples thereof include ester oils produced from fatty acids and alcohols, such as those produced from fatty acids having odd or even hydrocarbon groups and alcohols, as described below.

[0034] The fatty acid used as a raw material for the ester oil is not particularly limited in terms of the number of carbon atoms, whether or not it is branched, its valence, etc., and may be, for example, a higher fatty acid, a fatty acid having a cyclo ring, or a fatty acid having an aromatic ring. The alcohol used as a raw material for the ester oil is not particularly limited in terms of the number of carbon atoms, whether or not it is branched, its valence, etc., and may be, for example, an aliphatic alcohol, an alcohol having a cyclo ring, or an alcohol having an aromatic ring.

[0035] Specific examples of ester oils include (1) ester compounds of aliphatic monoalcohols and aliphatic monocarboxylic acids, such as octyl palmitate, dodecyl oleate, oleyl laurate, oleyl oleate, isotridecyl stearate, and isotetracosyl oleate; (2) ester compounds of aliphatic polyhydric alcohols and aliphatic monocarboxylic acids, such as 1,6-hexanediol didecanate, glycerin dioleate, glycerin trioleate, trimethylolpropane trilaurate, trimethylolpropane trioleate, triester of trimethylolpropane and coconut fatty acid, sorbitan monooleate, sorbitan trioleate, and pentaerythritol tetraoctate; and (3) diisostearyl adipate, dioleate, and the like. (3) ester compounds of an aliphatic monoalcohol and an aliphatic polycarboxylic acid, such as bisphenol A dilaurate, diisostearyl isophthalate, diisostearyl thiodipropionate, dioleyl thiodipropionate, and diisocetyl thiodipropionate; (4) ester compounds of an aromatic monoalcohol and an aliphatic monocarboxylic acid, such as benzyl oleate and benzyl laurate; (5) ester compounds of an aromatic polyhydric alcohol and an aliphatic monocarboxylic acid, such as bisphenol A dilaurate; (6) ester compounds of an aliphatic monoalcohol and an aromatic polycarboxylic acid, such as bis-2-ethylhexyl phthalate, diisostearyl isophthalate, and trioctyl trimellitate; and (7) natural oils and fats, such as coconut oil, rapeseed oil, sunflower oil, soybean oil, castor oil, sesame oil, fish oil, and beef tallow.

[0036] Examples of mineral oils include aromatic hydrocarbons, paraffinic hydrocarbons, naphthenic hydrocarbons, etc. More specifically, examples include spindle oil, liquid paraffin, etc. Commercially available products can be used as these mineral oils.

[0037] The polyolefin used is a poly-α-olefin used as a smoothing component. Specific examples of polyolefins include poly-α-olefins obtained by polymerizing 1-butene, 1-hexene, 1-decene, etc. Commercially available poly-α-olefins can be used as appropriate.

[0038] These lubricants may be used alone or in combination of two or more. Examples of ionic surfactants include anionic surfactants, cationic surfactants, and amphoteric surfactants.

[0039] As the anionic surfactant, known surfactants can be appropriately used. Specific examples of anionic surfactants include (1) phosphate salts of fatty alcohols, such as lauryl phosphate salts, cetyl phosphate salts, octyl phosphate salts, oleyl phosphate salts, and stearyl phosphate salts; (2) phosphate salts of fatty alcohols to which at least one alkylene oxide selected from ethylene oxide and propylene oxide has been added, such as polyoxyethylene lauryl ether phosphate salts, polyoxyethylene oleyl ether phosphate salts, and polyoxyethylene stearyl ether phosphate salts; (3) aliphatic sulfonates or aromatic sulfonates, such as lauryl sulfonate, myristyl sulfonate, cetyl sulfonate, oleyl sulfonate, stearyl sulfonate, tetradecane sulfonate, dodecyl benzene sulfonate, and secondary alkane sulfonate (C13-15); (4) sulfate salts of fatty alcohols, such as lauryl sulfate salts, oleyl sulfate salts, and stearyl sulfate salts; (5) polyoxyethylene lauryl ether sulfate salts, polyoxyethylene stearyl ether sulfate salts, and polyoxyethylene stearyl ether sulfate salts. Sulfate salts of fatty alcohols to which at least one alkylene oxide selected from ethylene oxide and propylene oxide is added, such as alkylene (polyoxyethylene, polyoxypropylene) lauryl ether sulfate salts and polyoxyethylene oleyl ether sulfate salts; (6) castor oil fatty acid sulfate salts, sesame oil fatty acid sulfate salts, tall oil fatty acid sulfate salts, soybean oil fatty acid sulfate salts, rapeseed oil fatty acid sulfate salts, palm oil fatty acid sulfate salts, and lard fatty acid sulfate salts (7) sulfates of fats and oils such as sulfates of castor oil, sulfates of sesame oil, sulfates of tall oil, sulfates of soybean oil, sulfates of rapeseed oil, sulfates of palm oil, sulfates of lard, sulfates of beef tallow, and sulfates of whale oil; (8) fatty acid salts such as laurates, oleates, and stearates; and (9) sulfosuccinate salts of fatty alcohols such as dioctyl sulfosuccinate.Examples of counter ions of anionic surfactants include alkali metal salts such as potassium salts and sodium salts, ammonium salts, and alkanolamine salts such as triethanolamine.

[0040] Known cationic surfactants can be appropriately used, and specific examples of the cationic surfactant include lauryltrimethylammonium chloride, cetyltrimethylammonium chloride, stearyltrimethylammonium chloride, behenyltrimethylammonium chloride, didecyldimethylammonium chloride, and 1,2-dimethylimidazole.

[0041] As the amphoteric surfactant, known surfactants can be appropriately used, and specific examples of amphoteric surfactants include betaine-type amphoteric surfactants. As the nonionic surfactant, known surfactants can be appropriately used.Specific examples of nonionic surfactants include (1) compounds in which alkylene oxide having 2 to 4 carbon atoms is added to organic acids, organic alcohols, organic amines, and / or organic amides, such as polyoxyethylene dilaurate, polyoxyethylene oleate, polyoxyethylene dioleate, polyoxyethylene octyl ether, polyoxyethylene lauryl ether, polyoxyethylene lauryl ether methyl ether, polyoxyethylene polyoxypropylene lauryl ether, polyoxypropylene lauryl ether methyl ether, polyoxyethylene oleyl ether, polyoxybutylene oleyl ether, polyoxyethylene polyoxypropylene nonyl ether, polyoxyethylene polyoxypropylene octyl ether, ethylene oxide adduct of 2-hexylhexanol, polyoxyethylene 2-ethyl-1-hexyl ether, polyoxyethylene isononyl ether, polyoxyethylene dodecyl ether, compounds in which ethylene oxide is added to secondary dodecyl alcohol, and polyoxyethylene tridecyl (2) polyoxyalkylene polyhydric alcohol fatty acid ester type nonionic surfactants such as polyoxyalkylene sorbitan trioleate, polyoxyalkylene coconut oil, polyoxyalkylene castor oil, polyoxyalkylene hydrogenated castor oil, polyoxyalkylene hydrogenated castor oil trioctanate, and polyoxyalkylene hydrogenated castor oil maleate, stearate, or oleate ester; (3) alkyl amide type nonionic surfactants such as stearic acid diethanolamide and diethanolamine monolauroamide; (4) polyoxyalkylene fatty acid amide type nonionic surfactants such as polyoxyethylene diethanolamine monooleylamide, polyoxyethylene laurylamine, and polyoxyethylene tallowamine; and (5) ether-ester compounds such as copolymers of polyoxyethylene, dimethyl phthalate, and lauryl alcohol.

[0042] These surfactants may be used alone or in combination of two or more. For example, in the case of a finish for spinning-false-twisting processing, the content of the smoothing agent in the finish is, for example, 0% by mass or more and 75% by mass or less. The content of the nonionic surfactant in the finish is, for example, 9% by mass or more and 99% by mass or less. The content of the ionic surfactant in the finish is, for example, 0.5% by mass or more and 10% by mass or less. By specifying the content within these ranges, it is possible to improve the manufacturing characteristics in the manufacturing process of drawn false-twisted yarn.

[0043] (volatile diluent) Specific examples of volatile diluents include water, organic solvents, low-viscosity mineral oils, etc. Specific examples of organic solvents include hexane, ethanol, isopropanol, ethylene glycol, propylene glycol, diethyl ether, toluene, xylene, dimethylformamide, methyl ethyl ketone, chloroform, etc. Specific examples of low-viscosity mineral oils include those with a kinematic viscosity of 5 mm at 30°C. 2 / s or less, more specifically, paraffin having 11 to 13 carbon atoms, paraffin having 12 carbon atoms, paraffin having 13 to 15 carbon atoms, paraffin having 14 carbon atoms, etc. The volatile diluent is preferably one containing water for ease of handling. These volatile diluents may be used alone or in combination of two or more.

[0044] The water content in the volatile diluent is 、9 0 mass% or more , good The content is preferably 95% by mass or more. By specifying the content within this range, the cloud point of the diluted solution can be further increased. The electrical conductivity of water used as a volatile diluent is preferably 0 μs / cm or more and less than 100 μs / cm, more preferably 0 μs / cm or more and less than 50 μs / cm. By specifying this range, yarn breakage in subsequent processes can be further reduced, and the quality of the resulting synthetic fiber can be further improved. The electrical conductivity of water can be measured using a commercially available electrical conductivity meter, with the water being measured at a temperature of 25°C.

[0045] Here, a volatile diluent means a material that completely volatilizes when heat-treated for two hours at 105°C. The proportion of the treating agent in the diluted solution can be calculated from the proportion of the remaining mass of the sample when, for example, 10 g of the diluted solution is placed in a petri dish and heat-treated for two hours at 105°C.

[0046] When the total content of the treatment agent and volatile diluent is 100% by mass, the treatment agent is contained in an amount of 5% to 20% by mass, and the volatile diluent is contained in an amount of 80% to 95% by mass. By specifying these ranges, the application properties of the diluent to synthetic fibers can be improved.

[0047] (Application process) The diluent application step is carried out using an application device that applies the diluent. There are no particular restrictions on the proportion of the diluent applied to the synthetic fibers, but it is preferable to apply the diluent as a treatment agent at a proportion of 0.1% by mass to 5% by mass (excluding solvents such as water) relative to the synthetic fibers. By specifying this range, the manufacturing characteristics of the synthetic fibers can be improved.

[0048] The method for applying the diluent is not particularly limited, and known methods such as roller oiling, guide oiling using a metering pump, immersion oiling, and spray oiling can be used.

[0049] The diluent attached to the synthetic fibers may be subjected to a drying process to evaporate the volatile diluent. Furthermore, in the case of spinning and drawing applications (FDY) in the production of flat yarn, a drawing process including a drawing treatment is carried out after the drying process.

[0050] Furthermore, in the case of spinning-false-twisting applications (POY-DTY) in the production of false-twist textured yarn (DTY), a partially oriented yarn is obtained in the spinning process. Partially oriented yarn is obtained by spinning at high speed after spinning in the spinning process, without going through a drawing treatment, and thereby performing partial drawing. The obtained partially oriented yarn is further subjected to a drawing and false-twisting process to obtain a drawn textured yarn (DTY). The spinning and drawing process and the drawing and false-twisting process can be performed by known methods and known devices.

[0051] (Effects of this embodiment) The method for producing synthetic fibers according to the above embodiment and the effects of the diluent used therein will now be described.

[0052] (1) In the above embodiment, in the synthetic fiber manufacturing method having a cooling step of blowing cooling air onto the running yarn and an application step of applying a diluent, the light transmittance and cloud point of the diluent containing a predetermined concentration of a treatment agent are specified within predetermined ranges.

[0053] Therefore, it is possible to reduce yarn breakage in subsequent processes and improve the quality of the resulting synthetic fiber. In particular, in the case of spinning-false-twisting processes (POY-DTY), it is possible to reduce yarn breakage in the drawing-false-twisting process and improve the quality of the drawn-false-twisted yarn, for example, by reducing dye unevenness.

[0054] (2) When the volatile diluent contains water and the electrical conductivity of the water is 0 μs / cm or more and less than 50 μs / cm, the quality of the resulting synthetic fiber can be further improved. In particular, in the case of spinning-false-twisting (POY-DTY) applications, the quality of the drawn-false-twisted yarn obtained after the drawing-false-twisting process can be further improved.

[0055] (3) When the water content in the volatile diluent is 90% by mass or more, the cloud point of the diluted solution can be improved. (4) In the above embodiment, a configuration in which cooling air is blown in a direction approximately parallel to the running yarn may be adopted. When an annular extension cylinder is connected to the downstream opening of the cooling cylinder of the above-mentioned annular cooling device as a guide plate so that the cooling air is blown in a direction approximately parallel to the running yarn, the temperature of the supply device may rise, particularly when the supply device is provided near the opening of the extension cylinder.

[0056] In such a configuration, yarn breakage may occur in the subsequent steps after the application of the treatment agent. Furthermore, the quality of the resulting synthetic fiber may be reduced. Particularly in the case of spinning-false-twisting applications (POY-DTY), yarn breakage may occur in the drawing-false-twisting step after the application of the treatment agent. Furthermore, the quality of the resulting drawn-false-twisted yarn may be reduced, for example, uneven dyeing may occur. By using the dilution liquid of this embodiment, in which the light transmittance and cloud point of the dilution liquid are set within predetermined ranges, yarn breakage can be further reduced in the subsequent steps after the application of the treatment agent, and the quality of the resulting synthetic fiber can be further improved.

[0057] (5) The temperature of the applicator that applies the diluent varies, particularly depending on how the cooling air described above is received. When the applicator has a cooling step or cooling device that blows cooling air onto the running yarn spun from the spinneret in a direction approximately perpendicular and / or approximately parallel to the running direction, the temperature of the applicator rises to, for example, 30°C or more, 35°C or more, or 40°C or more. As the temperature of the applicator rises, the temperature of the diluent also rises. With the synthetic fiber manufacturing method of this embodiment, even if the diluent adheres to the synthetic fiber in a state where the diluent temperature is elevated, it is possible to reduce yarn breakage in subsequent processes and improve the quality of the synthetic fiber.

[0058] (Example of change) The above embodiment may be modified as follows: The above embodiment and the following modifications may be combined with each other within the scope of technical compatibility.

[0059] The above-mentioned treatment agents and dilutions may further contain components commonly used in treatment agents, such as stabilizers, antistatic agents, binders, antioxidants, UV absorbers, defoamers, preservatives, and rust inhibitors, during or after production of the treatment agents, etc., to maintain the quality of the treatment agents, etc., within the limits that do not impair the effects of the present invention. [Example]

[0060] In the following, examples will be given to more specifically explain the configuration and effects of the present invention, but the present invention is not limited to these examples. Reference example, In the comparative examples, unless otherwise specified, parts means parts by mass and % means % by mass.

[0061] Test Section 1 (Preparation of Dilution Solution (1)) ( Reference example 1-1) As shown in Table 1, by mixing 10 parts (%) of DELION FF-2000 (Takemoto Yushi Co., Ltd.), a spinning-false-twisting oil agent, as a treatment agent and 90 parts (%) of water (electrical conductivity 0.5 μs / cm) as a volatile diluent, Reference example A 1-1 dilution was prepared.

[0062] ( Reference example 1-2 to 1-13, Comparative Examples 1-1 to 1-5) Reference example The diluted solutions of 1-2 to 1-13 and Comparative Examples 1-1 to 1-5 are Reference example In the same manner as in the diluted solution 1-1, a solution containing the treating agent and the volatile diluent in the proportions shown in Table 1 was prepared.

[0063] The type and content of the treatment agent, and the type and content of the volatile diluent are shown in the "Treatment Agent" column and the "Volatile Diluent" column of Table 1, respectively. In addition, the electrical conductivity of the water used in the volatile diluent, the light transmittance of the diluted solution, and the cloud point of the diluted solution were measured as described below, and the results are shown in the "Electrical Conductivity of Water" column, the "Light Transmittance" column, and the "Cloud Point" column in Table 1, respectively.

[0064] (electrical conductivity of water) each Reference example The temperature of the water used in the comparative examples was adjusted to 25°C, and the electrical conductivity was measured using an electrical conductivity meter (LAQUA twin EC-33B manufactured by HORIBA Corp.) The unit of electrical conductivity in the table is μS / cm.

[0065] (Light transmittance of diluted solution) The light transmittance of the diluted solution obtained in Test Section 1 was measured at a wavelength of 750 nm using a spectrophotometer (Shimadzu Corporation UV-1280 ultraviolet spectrophotometer). The measurement temperature was set to 25°C. A quartz cell with a cell length of 10 mm was used.

[0066] (Cloud point of treatment agent) The cloud point is defined in the "Surfactant Terminology" section of JIS K 3211 as "the temperature at which an aqueous surfactant solution begins to become cloudy when the temperature is increased." Therefore, it was measured using the following method.

[0067] The diluted solution obtained in Test Section 1 was poured into a test tube to a height of approximately 40 mm, and a thermometer was placed inside. The solution was heated to a temperature approximately 2-3°C higher than the temperature at which clouding occurs while stirring vigorously with the thermometer. The solution was then air-cooled again while stirring vigorously, and the temperature at which it became transparent was measured as the cloud point. If the diluted solution was already cloudy at room temperature, it was cooled while stirring vigorously until it became transparent, and then gradually heated again while stirring vigorously to the temperature at which clouding occurs. The solution was then gradually cooled while stirring, and the temperature at which it became transparent was measured as the cloud point.

[0068] [Table 1]

[0069] Details of the treatment agents and volatile diluents listed in Table 1 are as follows: <Treatment agent> The commercially available products used were DELION FF-2000 to DELION FF-2007, which are spinning-false-twisting finishes manufactured by Takemoto Oil & Fat Co., Ltd. The composition is a typical one, containing 0 to 75% by mass of a lubricant, 9 to 99% by mass of a nonionic surfactant, 0.5 to 10% by mass of an ionic surfactant, and other components in the range of 0.05 to 5% by mass.

[0070] <Volatile diluent> D-1: Paraffin with carbon numbers 13 and 14 Test Category 2 (Manufacturing method of partially oriented yarn) Chips of polyethylene terephthalate with an intrinsic viscosity of 0.64 and a titanium oxide content of 0.2% were dried in a conventional manner, then spun at 295°C using an extruder, extruded from a nozzle, and cooled to solidify.

[0071] In test section 2, a horizontally blown cooling device was used as the cooling device during spinning, in which cooling air was blown in a direction approximately perpendicular to the running direction of the running yarn. The diluted solution obtained in Test Section 1 was then applied to the running yarn by a guide oiling method using a metering pump as the application device, so that the treatment agent was applied at 0.5% relative to the running yarn. The temperature of the spray nozzle was 30°C. The yarn was then focused using a guide and wound up at a speed of 3,300 m / min without mechanical stretching, yielding a 10 kg wound cake of 128 dtex, 36 filament partially oriented yarn (POY).

[0072] Test Category 3 (Evaluation of breakage of drawn twisted yarn (DTY)) The partially drawn yarn (POY) to which the dilution was applied was false-twisted using a contact heater false-twisting machine (TMT Machinery, product name ATF-21) under the following conditions: processing speed = 650 m / min, draw ratio = 1.70, twisting method = 3-axis disc external friction method (one entry guide disc, one exit guide disc, four hard polyurethane discs), disc speed / yarn speed (D / Y) = 1.7, twist-side heater = 2 m length, surface temperature = 180 °C, untwist-side heater = none, to obtain drawn false-twisted yarn (DTY). Under these conditions, false-twisting was performed for one day using 12 spindles (number of simultaneous false-twisting processes per false-twisting machine: 12), and the number of breakages of the drawn false-twisted yarn was counted. The results are shown in the "DTY Breakage" column of Table 1.

[0073] ·Evaluation criteria for breakage of drawn false-twisted yarn 3 (Good): Occurrences are 0-1 2 (OK): Occurs 2-4 times 1 (Not allowed): Occurs 5 or more times Test category 4 (evaluation of staining spots) In test section 3, the drawn false-twisted yarn was subjected to a draw-twist process, and then the resulting drawn false-twisted yarn was used on a cylindrical knitting machine to produce a knitted fabric with a diameter of 70 mm and a length of 1.2 m. The produced knitted fabric was dyed using a disperse dye (Kayalon Polyester Blue EBL-E, product name, manufactured by Nippon Kayaku Co., Ltd.) by a high-pressure dyeing method. The dyed knitted fabric was washed with water, reduced, and dried according to the usual method, and then attached to a 70 mm diameter, 1 m long iron cylinder. The number of darkly dyed areas on the knitted fabric surface was counted with the naked eye, and the dyeability was evaluated according to the following criteria. The results are shown in the "Dyeing unevenness" column in Table 1. Note that "*1" in the table indicates that the drawn false-twisted yarn was not evaluated because the yarn breakage rating was "fail."

[0074] Evaluation criteria for staining spots 3 (Good): No dark staining 2 (Acceptable): If there are 1 to 7 dark stained areas 1 (Not acceptable): If there are 8 or more darkly stained areas As is clear from the results in Table 1, Reference exampleThe diluted solution was evaluated as fair or better in terms of yarn breakage and dye unevenness of the drawn false-twisted yarn. According to the present invention, it is possible to reduce yarn breakage in the drawing and false-twisting process, which is a post-process after the application of the treatment agent, and to improve the quality of the drawn false-twisted yarn as a synthetic fiber.

[0075] Test Section 5 (Preparation of Dilution Solution (2)) (Examples 2-1 to 2-13, Comparative Examples 2-1 to 2-5) The dilutions of Examples 2-1 to 2-13 and Comparative Examples 2-1 to 2-5 were: Reference example In the same manner as in the diluted solution 1-1, a solution containing the processing agent and the volatile diluent in the proportions shown in Table 2 was prepared.

[0076] The type and content of the treatment agent, and the type and content of the volatile diluent are shown in the "Treatment Agent" column and the "Volatile Diluent" column of Table 2, respectively. Additionally, the electrical conductivity of the water used in the volatile diluent, the light transmittance of the diluted solution, and the cloud point of the diluted solution were measured using the same method as in Test Section 1. The results are shown in the "Electrical Conductivity of Water" column, the "Light Transmittance" column, and the "Cloud Point" column in Table 2, respectively.

[0077] [Table 2]

[0078] Test Section 6 (Manufacturing method and evaluation of partially oriented yarn) Chips of polyethylene terephthalate with an intrinsic viscosity of 0.64 and a titanium oxide content of 0.2% were dried in a conventional manner, then spun at 295°C using an extruder, extruded from a nozzle, and cooled to solidify.

[0079] In test section 6, a circular cooling device was used as the cooling device during spinning, in which cooling air was blown in a direction approximately parallel to the running direction of the running yarn. The diluted solution obtained in Test Section 5 was then applied to the running yarn by a guide oiling method using a metering pump as the application device, so that the treatment agent concentration was 0.5% relative to the running yarn. The temperature of the spray nozzle was 40°C. The yarn was then focused using a guide and wound at a speed of 3,300 m / min without mechanical stretching, yielding a 10 kg wound cake of partially oriented yarn with 128 dtex and 36 filaments.

[0080] The evaluation of yarn breakage and dyeing unevenness of the drawn false-textured yarn (DTY) was carried out using the same methods as in the above test sections 3 and 4. The results are shown in the "DTY yarn breakage" and "dying unevenness" columns of Table 2, respectively.

[0081] As is clear from the results in Table 2, the diluted solutions of each Example were evaluated as fair or better in terms of yarn breakage and dye unevenness of the drawn false-twisted yarn. According to the present invention, even when the cooling device used during spinning is a circular cooling device, it is possible to reduce yarn breakage in the drawing and false-twisting process, which is a subsequent process after application of the treatment agent, and to improve the quality of the drawn false-twisted yarn as a synthetic fiber.

[0082] Next, the technical ideas that can be understood from the above-described embodiment and other examples will be described below. A twenty-first aspect of the present invention relates to a method for producing synthetic fibers, the method comprising: a cooling step of blowing cooling air onto a running yarn spun from a spinneret in a direction substantially perpendicular and / or substantially parallel to the running direction; and an application step of applying a diluted solution of a synthetic fiber treatment agent to the cooled running yarn, wherein the diluted solution of the synthetic fiber treatment agent contains a synthetic fiber treatment agent and a volatile diluent, and when the total content of the synthetic fiber treatment agent and the volatile diluent is taken as 100% by mass, the synthetic fiber treatment agent accounts for 5% by mass or more and 20% by mass or less and the volatile diluent accounts for 80% by mass or more and 95% by mass or less, respectively; the diluted solution has a light transmittance of 90% or more at a wavelength of 750 nm at 25°C; and the cloud point of the diluted solution is 30°C or higher.

[0083] In a twenty-second aspect of the method for producing a synthetic fiber according to the twenty-first aspect, the dilution liquid has a cloud point of 35° C. or higher. In a twenty-third aspect of the method for producing a synthetic fiber according to the twenty-first or twenty-second aspect, the dilution liquid has a cloud point of 40° C. or higher.

[0084] A twenty-fourth aspect is the method for producing synthetic fibers according to any one of the twenty-first to twenty-third aspects, wherein the volatile diluent contains water, and the water has an electrical conductivity of 0 μs / cm or more and less than 50 μs / cm.

[0085] A twenty-fifth aspect is the method for producing synthetic fibers according to any one of the twenty-first to twenty-fourth aspects, wherein the volatile diluent contains water at a content of 90 mass % or more. In a twenty-sixth aspect of the method for producing a synthetic fiber according to any one of the twenty-first to twenty-fifth aspects, the cooling air is blown in a direction substantially parallel to the running direction of the running yarn.

[0086] A twenty-seventh aspect is the method for producing a synthetic fiber according to any one of the twenty-first to twenty-sixth aspects, wherein the synthetic fiber is a partially oriented yarn. A twenty-eighth aspect of the method for producing a drawn false-twisted yarn is characterized by using a partially oriented yarn obtained by the method for producing a synthetic fiber according to the twenty-seventh aspect.

[0087] A diluted solution of a synthetic fiber treatment agent in Aspect 29 is a diluted solution of a synthetic fiber treatment agent containing a synthetic fiber treatment agent and a volatile diluent, wherein, when the total content of the synthetic fiber treatment agent and the volatile diluent is 100% by mass, the synthetic fiber treatment agent accounts for 5% by mass to 20% by mass and the volatile diluent accounts for 80% by mass to 95% by mass, the diluted solution has a light transmittance of 90% or more at a wavelength of 750 nm at 25°C, and the cloud point of the diluted solution is 30°C or higher.

[0088] A thirtyth aspect is the diluted solution of the treatment agent for synthetic fibers according to the twenty-ninth aspect, wherein the diluted solution has a cloud point of 35° C. or higher. In a thirty-first aspect, in the diluted solution of the treatment agent for synthetic fibers according to the twenty-ninth or thirtyth aspect, the diluted solution has a cloud point of 40° C. or higher.

[0089] A thirty-second aspect relates to the diluted solution of the treatment agent for synthetic fibers according to any one of aspects twenty-ninth to thirty-first, wherein the volatile diluent contains water, and the electrical conductivity of the water is 0 μs / cm or more and less than 50 μs / cm.

[0090] A thirty-third aspect is the diluted solution of the treatment agent for synthetic fibers according to any one of aspects twenty-ninth to thirty-second, wherein the volatile diluent contains 90 mass % or more of water. Aspect 34 is applied to a spinning apparatus including a cooling device that blows cooling air onto a running yarn spun from a spinneret in a direction approximately perpendicular and / or approximately parallel to the running direction, using a diluted solution of the synthetic fiber treatment agent according to any one of Aspects 29 to 33, and an application device that applies the diluted solution of the synthetic fiber treatment agent to the cooled running yarn.

[0091] A thirty-fifth aspect is the diluted solution of the treatment agent for synthetic fibers according to the thirty-fourth aspect, wherein the cooling device blows the cooling air in a direction approximately parallel to the running direction of the running yarn. A thirty-sixth aspect of the treatment agent for synthetic fibers is characterized in that it is used in a diluted solution of the treatment agent for synthetic fibers according to any one of the twenty-ninth to thirty-fifth aspects.

Claims

1. A method for producing synthetic fibers, comprising: a cooling step of blowing cooling air onto a running yarn spun from a spinneret in a direction substantially parallel to the running direction; and an application step of applying a diluted solution of a synthetic fiber treatment agent to the cooled running yarn, The diluted solution of the synthetic fiber treatment agent contains a synthetic fiber treatment agent and a volatile diluent, the synthetic fiber treatment agent contains a nonionic surfactant and an ionic surfactant, and the volatile diluent contains 90 mass % or more of water, When the total content of the synthetic fiber treatment agent and the volatile diluent is 100% by mass, the content of the synthetic fiber treatment agent is 5% by mass or more and 20% by mass or less, and the content of the volatile diluent is 80% by mass or more and 95% by mass or less, A method for producing synthetic fibers, characterized in that a diluent is selected that has a light transmittance of 90% or more at a wavelength of 750 nm at 25°C and a cloud point of 30°C or higher.

2. 2. The method for producing synthetic fibers according to claim 1, wherein the dilution liquid has a cloud point of 35° C. or higher.

3. 2. The method for producing synthetic fibers according to claim 1, wherein the dilution liquid has a cloud point of 40° C. or higher.

4. 2. The method for producing synthetic fibers according to claim 1, wherein the volatile diluent contains water, and the electrical conductivity of the water is 0 μs / cm or more and less than 50 μs / cm.

5. The method for producing synthetic fibers according to claim 1, wherein the cooling air is further blown in a direction substantially perpendicular to the running direction of the running yarn.

6. The method for producing synthetic fibers according to any one of claims 1 to 5, wherein the synthetic fibers are partially oriented yarns.

7. A method for producing a drawn false-twisted yarn, comprising using a partially oriented yarn obtained by the method for producing a synthetic fiber according to claim 6.

8. A method for producing a diluted solution of a synthetic fiber treatment agent containing a synthetic fiber treatment agent and a volatile diluent, which is applied to a spinning apparatus equipped with a cooling device that blows cooling air onto a running yarn spun from a nozzle in a direction approximately parallel to the running direction, and an application device that applies a diluted solution of a synthetic fiber treatment agent to the cooled running yarn, the method comprising: the synthetic fiber treatment agent contains a nonionic surfactant and an ionic surfactant, and the volatile diluent contains 90% by mass or more of water; A method for producing a diluted solution of a treatment agent for synthetic fibers, characterized in that, when the total content of the treatment agent for synthetic fibers and the volatile diluent is taken as 100% by mass, the content of the treatment agent for synthetic fibers is 5% by mass or more and 20% by mass or less, and the content of the volatile diluent is 80% by mass or more and 95% by mass or less, the diluted solution has a light transmittance of 90% or more at a wavelength of 750 nm at 25°C, and a cloud point of 30°C or higher.

9. 9. The method for producing a diluted solution of a treatment agent for synthetic fibers according to claim 8, wherein the cloud point of the diluted solution is 35[deg.] C. or higher.

10. 9. The method for producing a diluted solution of a treatment agent for synthetic fibers according to claim 8, wherein the cloud point of the diluted solution is 40° C. or higher.

11. 9. The method for producing a diluted solution of a synthetic fiber treatment agent according to claim 8, wherein the volatile diluent contains water, and the electrical conductivity of the water is 0 μs / cm or more and less than 50 μs / cm.

12. 9. The method for producing a diluted solution of a synthetic fiber processing agent according to claim 8, wherein the cooling device further blows the cooling air in a direction substantially perpendicular to the running direction of the running yarn.

13. A method for producing a diluted solution of a treatment agent for synthetic fibers as described in Claim 8, wherein the application device is arranged above the ventilation after the cooling air has been blown onto the running yarn.

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