Treating agent for polyester short-fiber spunlace, diluted treating agent for polyester short-fiber spunlace, first treating agent for polyester short-fiber spunlace, second treating agent for polyester short-fiber spunlace, and polyester short fiber

Abstract

To enhance antistatic properties of polyester short fibers imparted with a polyester short-fiber spunlace treating agent and to enhance roller card web uniformity.SOLUTION: The polyester short-fiber spunlace treating agent contains a fatty acid derivative (A), a fatty acid derivative (B), and an organic phosphate ester salt (C), the fatty acid derivative (A) being at least one alkylene oxide adduct selected from linoleic acid and linolenic acid, and the fatty acid derivative (B) being at least one alkylene oxide adduct selected from oleic acid and stearic acid.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a treating agent for polyester staple fiber spunlace, a diluted solution of a treating agent for polyester staple fiber spunlace, a first treating agent for polyester staple fiber spunlace, a second treating agent for polyester staple fiber spunlace, and polyester staple fibers. [Background technology]

[0002] For example, fiber treatment agents may be applied to the surfaces of synthetic fibers during spinning, drawing, finishing, etc. Generally, a roller-carded web of synthetic fibers is produced in a carding process using a roller card, and then the fibers constituting the roller-carded web are entangled in a spunlace process to produce a nonwoven fabric.

[0003] For example, Patent Document 1 describes a treating agent for spunlace nonwoven fabric production that contains a fatty acid having 4 to 11 carbon atoms, an organic phosphate ester, a nonionic surfactant, etc. It describes that use of the treating agent for nonwoven fabric production results in excellent entanglement and scum suppression, and also reduces foaming during the spunlace process.

[0004] Patent Document 2 describes a fiber treatment agent for producing spunlace nonwoven fabrics that contains an ester compound of a dibasic acid and a diol, and an alkyl phosphate ester. It also describes that use of the fiber treatment agent for producing spunlace nonwoven fabrics can impart excellent smoothness and softness to fibers and suppress foaming during the spunlace process. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6605833 [Patent Document 2] Patent No. 4139130 Summary of the Invention [Problem to be solved by the invention]

[0006] Meanwhile, polyester staple fibers to which a fiber-treating agent has been applied are required to have improved antistatic properties and improved uniformity of the roller card web obtained in the carding process. [Means for solving the problem]

[0007] As a result of research aimed at solving the above problems, the present inventors have found that a polyester staple fiber treatment agent containing a specific fatty acid derivative and an organic phosphate ester salt is exactly suitable.

[0008] Various aspects for solving the above problems will be described. The treating agent for polyester staple fiber spunlace of Aspect 1 is summarized as containing the following fatty acid derivative (A), the following fatty acid derivative (B), and an organic phosphate ester salt (C). The treatment agent for polyester staple fiber spunlace contains the fatty acid derivative (A) and the fatty acid derivative (B) in a total amount of 25% by mass or more and 90% by mass or less, and the organic phosphate ester salt (C) in a proportion of 5% by mass or more and 65% by mass or less, based on the non-volatile content of the treatment agent for polyester staple fiber spunlace.

[0009] Fatty acid derivative (A): an alkylene oxide adduct of at least one selected from linoleic acid and linolenic acid. Fatty acid derivative (B): an alkylene oxide adduct of at least one selected from oleic acid and stearic acid.

[0010] Aspect 2 is the treating agent for polyester staple fiber spunlace according to Aspect 1, wherein the mass proportion of oxyalkylene groups in the molecular structure of the fatty acid derivative (A) and the fatty acid derivative (B) is 50 mass % or less, respectively.

[0011] In a third aspect, in the treating agent for polyester staple fiber spunlace according to the first or second aspect, when the mass of the fatty acid derivative (A) in the treating agent for polyester staple fiber spunlace is Am and the mass of the fatty acid derivative (B) in the treating agent for polyester staple fiber spunlace is Bm, the value of the mass ratio Am / Bm is 0.01 or more and 0.4 or less.

[0012] A fourth aspect is the treating agent for polyester staple fiber spunlace according to any one of the first to third aspects, wherein the organic phosphate ester salt (C) is a salt of a phosphate ester having an alkyl group having from 11 to 13 carbon atoms.

[0013] Aspect 5 is the treating agent for polyester staple fiber spunlace according to any one of Aspects 1 to 4, wherein the non-volatile content of the treating agent for polyester staple fiber spunlace contains the fatty acid derivative (A) and the fatty acid derivative (B) in a total amount of 30% by mass or more and 70% by mass or less, and the organic phosphate ester salt (C) in a proportion of 10% by mass or more and 60% by mass or less.

[0014] A sixth aspect is the treating agent for polyester staple fiber spunlace according to any one of the first to fifth aspects, further comprising the following diester (D). Diester (D): A diester of polyethylene glycol having a molecular weight of 200 or more and 800 or less and a monovalent fatty acid having 12 or more and 20 or less carbon atoms.

[0015] A seventh aspect is the treating agent for polyester staple fiber spunlace according to the sixth aspect, wherein the non-volatile components of the treating agent for polyester staple fiber spunlace contain the fatty acid derivative (A) and the fatty acid derivative (B) in a total amount of 30% by mass to 70% by mass, the organic phosphate ester salt (C) in an amount of 10% by mass to 60% by mass, and the diester (D) in an amount of 2% by mass to 10% by mass.

[0016] A diluted solution of a treatment agent for polyester staple fiber spunlace according to an eighth aspect is characterized in that it contains the treatment agent for polyester staple fiber spunlace according to any one of the first to seventh aspects, and water.

[0017] The first treatment agent for polyester staple fiber spunlace of embodiment 9 is used in combination with a second treatment agent for polyester staple fiber spunlace containing an organic phosphate ester salt (C), and is characterized in that it contains the following fatty acid derivative (A), the following fatty acid derivative (B), and optionally the following diester (D). The first treating agent for polyester staple fiber spunlace is used in combination with the second treating agent for polyester staple fiber spunlace so that the non-volatile components of the treating agent for polyester staple fiber spunlace mixed with the second treating agent for polyester staple fiber spunlace contain a total of 25% by mass or more and 90% by mass or less of the fatty acid derivative (A) and the fatty acid derivative (B), and 5% by mass or more and 65% by mass or less of the organic phosphate ester salt (C).

[0018] Fatty acid derivative (A): an alkylene oxide adduct of at least one selected from linoleic acid and linolenic acid. Fatty acid derivative (B): an alkylene oxide adduct of at least one selected from oleic acid and stearic acid.

[0019] Diester (D): A diester of polyethylene glycol having a molecular weight of 200 or more and 800 or less and a monovalent fatty acid having 12 or more and 20 or less carbon atoms. The second treatment agent for polyester staple fiber spunlace of Aspect 10 is used in combination with a first treatment agent for polyester staple fiber spunlace containing the following fatty acid derivative (A), the following fatty acid derivative (B), and optionally the following diester (D), and is characterized by containing an organic phosphate ester salt (C). The second treatment agent for polyester staple fiber spunlace is used in combination with the first treatment agent for polyester staple fiber spunlace so that the non-volatile components of the treatment agent for polyester staple fiber spunlace mixed with the first treatment agent for polyester staple fiber spunlace contain a total of 25% by mass or more and 90% by mass or less of the fatty acid derivative (A) and the fatty acid derivative (B), and 5% by mass or more and 65% by mass or less of the organic phosphate ester salt (C).

[0020] Fatty acid derivative (A): an alkylene oxide adduct of at least one selected from linoleic acid and linolenic acid. Fatty acid derivative (B): an alkylene oxide adduct of at least one selected from oleic acid and stearic acid.

[0021] Diester (D): A diester of polyethylene glycol having a molecular weight of 200 to 800 and a monovalent fatty acid having 12 to 20 carbon atoms. The polyester staple fiber of an eleventh aspect is characterized in that the treating agent for polyester staple fiber spunlace according to any one of the first to seventh aspects is adhered to the polyester staple fiber. [Effects of the Invention]

[0022] According to the present invention, the polyester staple fibers to which the treatment agent for polyester staple fiber spunlace has been applied can have improved antistatic properties and roller card web uniformity. DETAILED DESCRIPTION OF THE INVENTION

[0023] First Embodiment A first embodiment of the treating agent for polyester staple fiber spunlace (hereinafter simply referred to as the treating agent) of the present invention will be described below. The treating agent of this embodiment contains the following fatty acid derivative (A), the following fatty acid derivative (B), and an organic phosphate ester salt (C).

[0024] (Fatty acid derivative (A)) The fatty acid derivative (A) is an alkylene oxide adduct of at least one selected from linoleic acid and linolenic acid.

[0025] The alkylene oxide preferably has 2 or more and 4 or less carbon atoms, and more preferably has 2 or 3 carbon atoms. Specific examples of alkylene oxides having 2 or more and 4 or less carbon atoms include ethylene oxide (hereinafter also referred to as EO), propylene oxide (hereinafter also referred to as PO), butylene oxide, etc.

[0026] The number of moles of alkylene oxide added is not particularly limited, but is preferably 0.1 to 20 moles, more preferably 0.5 to 18 moles, and even more preferably 0.5 to 15 moles.

[0027] The number of moles of alkylene oxide added may be any range combining the above upper and lower limits. The number of moles of alkylene oxide added indicates the number of moles of alkylene oxide per mole of the compound to be added in the charged raw material. As the alkylene oxide, one type of alkylene oxide may be used alone, or two or more types of alkylene oxides may be used in appropriate combination. When two or more types of alkylene oxides are used, the addition form thereof may be any of block addition, random addition, and a combination of block addition and random addition, and is not particularly limited.

[0028] The fatty acid derivative (A) may be a dicarboxylic acid in which linoleic acid or linolenic acid is bonded to both ends of an alkylene oxide, or a monocarboxylic acid in which linoleic acid or linolenic acid is bonded to one end of an alkylene oxide. The fatty acid derivative (A) is preferably a monocarboxylic acid.

[0029] The mass proportion of oxyalkylene groups in the molecular structure of the fatty acid derivative (A) is preferably 50 mass% or less. When the mass proportion of oxyalkylene groups in the molecular structure of the fatty acid derivative (A) is 50 mass% or less, foaming of the water stream when sprayed with high-pressure water in the spunlace process is easily suppressed. In other words, foam suppression can be improved.

[0030] (Fatty acid derivative (B)) The fatty acid derivative (B) is an alkylene oxide adduct of at least one selected from oleic acid and stearic acid.

[0031] The alkylene oxide may be the same as the alkylene oxide in the fatty acid derivative (A). The fatty acid derivative (B) may be a dicarboxylic acid in which oleic acid or stearic acid is bonded to both ends of an alkylene oxide, or a monocarboxylic acid in which oleic acid or stearic acid is bonded to one end of an alkylene oxide. The fatty acid derivative (B) is preferably a monocarboxylic acid. However, the fatty acid derivative (B) does not include the diester (D) described below.

[0032] The mass proportion of oxyalkylene groups in the molecular structure of the fatty acid derivative (B) is preferably 50 mass% or less, which can improve the foam suppression properties when a high-pressure water stream is sprayed in the spunlace process.

[0033] It is more preferable that the mass proportion of oxyalkylene groups in the molecular structures of the fatty acid derivative (A) and the fatty acid derivative (B) is 50 mass% or less, respectively. When the mass proportion of oxyalkylene groups in the molecular structures of the fatty acid derivative (A) and the fatty acid derivative (B) is 50 mass% or less, respectively, the foam suppressing property can be further improved.

[0034] The mass proportion of oxyalkylene groups in the molecular structure of either the fatty acid derivative (A) or the fatty acid derivative (B) may be 50 mass % or less. (Organophosphate ester salt (C)) Examples of the organic phosphate salt (C) include salts of alkyl phosphate esters, alkenyl phosphate esters, etc. The alkyl group or alkenyl group constituting the alkyl phosphate ester is not particularly limited, and may be, for example, linear or branched.

[0035] Alcohols that can be used as raw materials for the organic phosphate salt (C) include monohydric aliphatic alcohols. Specific examples of monohydric aliphatic alcohols include (1) linear alkyl alcohols such as methanol, ethanol, propanol, butanol, pentanol, hexanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecanol, heptadecanol, octadecanol, nonadecanol, eicosanol, heneicosanol, docosanol, tricosanol, tetracosanol, pentacosanol, hexacosanol, heptacosanol, octacosanol, nonacosanol, and triacontanol; (2) isopropanol, isobutanol, isohexanol, 2-ethylhexanol, isononanol, isodecanol, isododecanol, isotridecanol, and isotetradecanol. (3) branched alkyl alcohols such as tetradecenol, isopentadecanol, isohexadecanol, isoheptadecanol, isooctadecanol, isononadecanol, isoeicosanol, isoheneicosanol, isodocosanol, isotricosanol, isotetracosanol, 2-decyltetradecanol, isopentacosanol, isohexacosanol, isoheptacosanol, isooctacosanol, isononacosanol, and isotriacontanol; (4) linear alkenyl alcohols such as tetradecenol, hexadecenol, heptadecenol, octadecenol, oleyl alcohol, and nonadecenol; (4) branched alkenyl alcohols such as isohexadecenol and isooctadecenol; and (5) cyclic alkyl alcohols such as cyclopentanol and cyclohexanol.

[0036] The phosphoric acid constituting the organic phosphate ester salt (C) is not particularly limited, and may be orthophosphoric acid or polyphosphoric acid such as diphosphoric acid. Examples of the organic phosphate salt (C) include amine phosphate salts and metal phosphate salts.

[0037] The amine constituting the amine salt may be any of a primary amine, a secondary amine, and a tertiary amine. Specific examples of amines constituting the amine salt include: (1) aliphatic amines such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, N-diisopropylethylamine, butylamine, dibutylamine, 2-methylbutylamine, tributylamine, octylamine, and dimethyllaurylamine; (2) aromatic amines or heterocyclic amines such as aniline, N-methylbenzylamine, pyridine, morpholine, piperazine, and derivatives thereof; (3) alkanolamines such as monoethanolamine, N-methylethanolamine, diethanolamine, triethanolamine, isopropanolamine, diisopropanolamine, triisopropanolamine, dibutylethanolamine, butyldiethanolamine, octyldiethanolamine, and lauryldiethanolamine; (4) arylamines such as N-methylbenzylamine; (5) polyoxyalkylene alkylamino ethers such as polyoxyethylene laurylamino ether and polyoxyethylene sterylamino ether; and (6) ammonia.

[0038] Examples of metal salts include alkali metal salts and alkaline earth metal salts. Specific examples of alkali metals constituting alkali metal salts include sodium, potassium, and lithium. Examples of alkaline earth metals constituting alkaline earth metal salts include metals belonging to Group 2 elements, such as calcium, magnesium, beryllium, strontium, and barium.

[0039] Specific examples of the organic phosphate ester salt (C) include undecyl phosphate potassium salt, dodecyl phosphate potassium salt, tridecyl phosphate potassium salt, dodecyl phosphate sodium salt, octadecyl phosphate potassium salt, and octyl phosphate potassium salt.

[0040] The organic phosphate ester salt (C) is preferably a salt of a phosphate ester of an aliphatic alcohol having from 11 to 13 carbon atoms. In other words, the organic phosphate ester salt (C) is preferably a salt of a phosphate ester having an alkyl group having from 11 to 13 carbon atoms. When the organic phosphate ester salt (C) is a salt of a phosphate ester having an alkyl group having from 11 to 13 carbon atoms, the antistatic properties of the polyester staple fiber can be further improved.

[0041] As for these organic phosphate ester salts (C), one type of organic phosphate ester salt (C) may be used alone, or two or more types of organic phosphate ester salts (C) may be used in appropriate combination.

[0042] The acid value of the organic phosphate salt (C) is appropriately set, but is preferably 5 to 100 KOH-mg / g, more preferably 10 to 80 KOH-mg / g. The acid value of the organic phosphate ester salt (C) is calculated from the following formula by dissolving the organic phosphate ester salt (C) in a mixed solvent of ethanol / xylene = 1 / 2 (volume ratio), setting it in a potentiometric titrator, and titrating it with a 0.1 mol / L potassium hydroxide methanol standard solution.

[0043] Acid value (KOH-mg / g)=(R×f×56.11×0.1) / S In the formula, f: Factor of 0.1 mol / L potassium hydroxide methanol standard solution S: Sample amount (g, solids equivalent) R: Amount (mL) of 0.1 mol / L potassium hydroxide methanol standard solution used to reach the inflection point (Content) When the mass of the fatty acid derivative (A) in the treatment agent is Am and the mass of the fatty acid derivative (B) is Bm, the mass ratio Am / Bm is preferably 0.01 or more and 0.4 or less.

[0044] When the value of the mass ratio Am / Bm is within the above range, the uniformity of the roller carded web of polyester staple fibers (hereinafter also referred to as roller carded web uniformity) can be further improved.

[0045] The roller card web uniformity means the property of obtaining a web with good appearance without any disturbance in the web texture when a web is produced by a roller carding process using polyester staple fibers to which a treatment agent has been applied.

[0046] The nonvolatile content of the treatment agent preferably contains a total of 30% to 70% by mass of the fatty acid derivative (A) and the fatty acid derivative (B), and 10% to 60% by mass of the organic phosphate ester salt (C).

[0047] When the contents of the fatty acid derivative (A), the fatty acid derivative (B), and the organic phosphate ester salt (C) are within the above ranges, it is possible to improve all of the antistatic property, the antifoaming property, and the hydrophilic property. The total of the fatty acid derivative (A), the fatty acid derivative (B), and the organic phosphate ester salt (C) in the nonvolatile content of the treatment agent does not necessarily have to be 100% by mass. For example, as described below, the treatment agent may contain a diester (D) or other components (E).

[0048] The non-volatile content of the treatment agent refers to the residue after the treatment agent is heat-treated at 105°C for 2 hours. The same applies hereinafter. The treating agent may further contain the following diester (D).

[0049] (Diester (D)) The diester (D) is a diester of polyethylene glycol having a molecular weight of 200 or more and 800 or less and a monovalent fatty acid having 12 or more and 20 or less carbon atoms.

[0050] By including the diester (D) in the treatment agent, the hydrophilicity of the polyester staple fibers and the roller card web uniformity can be further improved. The molecular weight mentioned above means the weight average molecular weight.

[0051] Examples of monovalent fatty acids having 12 to 20 carbon atoms include dodecanoic acid (lauric acid), tridecanoic acid, tetradecanoic acid (myristic acid), pentadecanoic acid, hexadecanoic acid (palmitic acid), heptadecanoic acid, octadecanoic acid (stearic acid), nonadecanoic acid, and icosanoic acid.

[0052] Specific examples of the diester (D) include a diester of polyethylene glycol having a mass average molecular weight of 200 and oleic acid (hereinafter also referred to as polyoxyethylene (mass average molecular weight 200) dioleate), a diester of polyethylene glycol having a mass average molecular weight of 800 and oleic acid (hereinafter also referred to as polyoxyethylene (mass average molecular weight 800) dioleate), a diester of polyethylene glycol having a mass average molecular weight of 400 and lauric acid (hereinafter also referred to as polyoxyethylene (mass average molecular weight 400) dilaurate), and a diester of polyethylene glycol having a mass average molecular weight of 600 and lauric acid (hereinafter also referred to as polyoxyethylene (mass average molecular weight 600) dilaurate).

[0053] As for these diesters (D), one type of diester (D) may be used alone, or two or more types of diesters (D) may be used in appropriate combination. The method for measuring the weight average molecular weight of the diester (D) is not limited, and any known method can be used, for example, gel permeation chromatography.

[0054] (Content) The non-volatile components of the treatment agent preferably contain a total of 30% by mass or more and 70% by mass or less of the fatty acid derivative (A) and the fatty acid derivative (B), 10% by mass or more and 60% by mass or less of the organic phosphate ester salt (C), and 2% by mass or more and 10% by mass or less of the diester (D).

[0055] In the nonvolatile content of the treatment agent, the total of the fatty acid derivative (A), the fatty acid derivative (B), the organic phosphate ester salt (C), and the diester (D) does not necessarily have to be 100% by mass. For example, as described below, the treatment agent may contain another component (E).

[0056] When the contents of the fatty acid derivative (A), the fatty acid derivative (B), the organic phosphate ester salt (C), and the diester (D) are within the above ranges, the roller card web uniformity of the polyester staple fibers and the emulsion stability of the treatment agent can be further improved.

[0057] (Other ingredients (E)) The treatment agent of this embodiment may contain other components (E). Examples of other components (E) include components commonly used in treatment agents, such as stabilizers, antistatic agents, binders, antioxidants, UV absorbers, surfactants, pH adjusters, and higher alcohols. Examples of surfactants include nonionic surfactants. Note that higher alcohols refer to monohydric alcohols having 6 or more carbon atoms.

[0058] Specific examples of the other component (E) include a compound in which 9 moles of EO and 9 moles of PO are randomly added to 1 mole of castor oil, a compound in which 7 moles of EO and 3 moles of PO are randomly added to 1 mole of castor oil, a compound in which 5 moles of EO and 5 moles of PO are randomly added to 1 mole of hydrogenated castor oil, a compound in which 9 moles of EO and 9 moles of PO are randomly added to 1 mole of hydrogenated castor oil, sodium salt of a secondary alkane sulfonate having from 11 to 14 carbon atoms, lauryl alcohol, oleic acid, potassium octanoate, an ester compound obtained by dehydration condensation of 0.1 mole of polyoxyethylene polyoxypropylene glycol (random polymer: mass average molecular weight 13,000, EO component ratio 75% by mass), 0.5 mole of polyethylene glycol (mass average molecular weight 600), and 0.4 mole of polyethylene glycol (mass average molecular weight 400) to 1 mole of sebacic acid, propylene glycol, ethylene glycol monobutyl ether phosphate potassium salt, and polyoxyethylene (mass average molecular weight 400) monolaurate.

[0059] These other components (E) may be used singly or in combination of two or more types of other components (E). In other words, the other component (E) may contain at least one of the above.

[0060] The content of the other component (E) is not particularly limited, and it can be contained within a range that does not impair the effects of the present invention. The content of the other component (E) in the nonvolatile content of the treatment agent can be, for example, 60% by mass or less, 50% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, 10% by mass or less, or 0% by mass. It can also be 5% by mass or more, or 10% by mass or more. The content of the other component (E) can also be within a range that combines the above upper and lower limits.

[0061] (Preservation form) The treatment agent may be configured as a one-component type containing the above-mentioned fatty acid derivative (A), fatty acid derivative (B), and organic phosphate ester salt (C), or from the viewpoint of improving formulation stability and storage stability, it may be configured as a two-component type treatment agent as shown below.

[0062] The two-component treatment agent is configured as a set including a first treatment agent for polyester staple fiber spunlace (hereinafter also referred to as the first treatment agent) containing a fatty acid derivative (A), a fatty acid derivative (B), and optionally a diester (D), and a second treatment agent for polyester staple fiber spunlace (hereinafter also referred to as the second treatment agent) containing an organic phosphate ester salt (C).Another component (E) may be contained in either or both of the first treatment agent and the second treatment agent.

[0063] A two-component treatment agent is composed of a first treatment agent and a second treatment agent that is composed as a separate agent from the first treatment agent during storage or distribution, etc. When used, the two-component treatment agent is prepared by mixing the first treatment agent and the second treatment agent.

[0064] (solvent) The treatment agent of the first embodiment can be mixed with a solvent, if necessary, to prepare a composition containing a treatment agent for polyester staple fiber spunlace or a diluted solution of the treatment agent for polyester staple fiber spunlace, and the composition can be stored or distributed in the form of a composition containing a treatment agent for polyester staple fiber spunlace.

[0065] The solvent has a boiling point of 105°C or lower at one atmospheric pressure. Examples of the solvent include water and organic solvents. Specific examples of water include ion-exchanged water, distilled water, hard water, and soft water. Specific examples of organic solvents include lower alcohols such as ethanol and propanol, and low-polarity solvents such as hexane. One type of these solvents may be used alone, or two or more types of solvents may be used in appropriate combination. Among these, polar solvents such as water and lower alcohols are preferred from the viewpoint of excellent dispersibility or solubility of each component, and water is more preferred from the viewpoint of excellent handleability.

[0066] <Actions and Effects of the First Embodiment> (1-1) The treatment agent of the first embodiment contains the fatty acid derivative (A), the fatty acid derivative (B), and the organic phosphate ester salt (C) described above. Therefore, the antistatic properties of the polyester staple fibers to which the treatment agent is applied and the uniformity of the roller carded web can be improved.

[0067] (1-2) Furthermore, by containing the above-mentioned diester (D), the hydrophilicity of the polyester staple fibers to which the treatment agent has been applied and the uniformity of the roller card web can be further improved.

[0068] Second Embodiment Next, a second embodiment of the diluted solution of a treatment agent for polyester staple fiber spunlace (hereinafter simply referred to as the diluted solution) of the present invention will be described. The following will focus on the differences from the first embodiment.

[0069] The dilution liquid of this embodiment contains the treatment agent and water. The dilution liquid is used as an emulsion by mixing the treatment agent with water. Specific examples of water include ion-exchanged water, distilled water, hard water, and soft water. Among these, ion-exchanged water and distilled water are preferably used.

[0070] The method for preparing the diluted solution is not particularly limited, and examples thereof include a method in which a predetermined amount of the treatment agent is added to a pre-measured amount of water. Furthermore, the diluted solution can also be prepared by a known mechanical emulsification method using a known homomixer, homogenizer, or the like.

[0071] The diluent may contain a known solvent other than water, such as the organic solvents described above. The concentration of the treatment agent in the diluted solution is not particularly limited. For example, the concentration of the treatment agent can be 30% by mass or more, 40% by mass or more, 50% by mass or more, or 60% by mass or more. It can also be 95% by mass or less, 90% by mass or less, 80% by mass or less, or 70% by mass or less. The concentration of the treatment agent can also be within any range that combines the above upper and lower limits.

[0072] <Actions and Effects of the Second Embodiment> In addition to the functions and effects of the first embodiment, the second embodiment has the following functions and effects.

[0073] (2-1) The dilution liquid of the second embodiment contains the treatment agent and water. Therefore, the treatment agent can be applied to the polyester staple fibers in the form of an emulsion. Furthermore, the dilution liquid is easy to handle because it contains water as a solvent.

[0074] <Third embodiment> Next, a third embodiment of the first treating agent for polyester staple fiber spunlace (first treating agent) of the present invention will be described. Differences from the first embodiment will be mainly described below. The first treating agent contains a fatty acid derivative (A), a fatty acid derivative (B), and optionally a diester (D).

[0075] The first treating agent is used in combination with a second treating agent for polyester staple fiber spunlace (hereinafter simply referred to as the second treating agent) containing an organic phosphate ester salt (C). That is, when used, the first treating agent and the second treating agent are mixed to prepare a mixture as a treating agent.

[0076] The fatty acid derivative (A), the fatty acid derivative (B), the organic phosphate ester salt (C), and the diester (D) are the same as the components described in the first embodiment. The first treatment agent may also contain the other component (E) described above.

[0077] (solvent) The first treating agent of the third embodiment is mixed with a solvent as needed to prepare a diluted first treating agent solution for polyester staple fiber spunlace (hereinafter also referred to as a diluted first treating agent solution). The first treating agent may be stored or distributed in the form of a diluted first treating agent solution. This configuration improves mixability and composition stability when diluted with a solvent or mixed with the second treating agent at the time of use. The solvent may be one of those exemplified in the first embodiment.

[0078] <Actions and Effects of the Third Embodiment> In addition to the functions and effects of the first and second embodiments, the third embodiment has the following functions and effects.

[0079] (3-1) The first treatment agent of the third embodiment contains a fatty acid derivative (A), a fatty acid derivative (B), and optionally a diester (D), and is used in combination with a second treatment agent containing an organic phosphate ester salt (C). This improves the formulation stability and storage stability of the first treatment agent during storage or distribution. Furthermore, by adjusting the mixing ratio with the second treatment agent, the components of the resulting treatment agent can be adjusted. Furthermore, the first treatment agent alone can be distributed separately from the second treatment agent.

[0080] <Fourth embodiment> Next, a fourth embodiment of the second treating agent (second treating agent) for polyester staple fiber spunlace of the present invention will be described. Differences from the first to third embodiments will be mainly described below. The second treating agent contains an organic phosphate ester salt (C). The second treating agent is used in combination with a first treating agent containing a fatty acid derivative (A), a fatty acid derivative (B), and optionally a diester (D). In other words, a mixture of the first treating agent and the second treating agent is prepared at the time of use.

[0081] The fatty acid derivative (A), the fatty acid derivative (B), the organic phosphate ester salt (C), and the diester (D) are the same as those described in the first embodiment. The second treatment agent may contain the other component (E) described above.

[0082] (solvent) The second treating agent of the fourth embodiment is mixed with a solvent as needed to prepare a diluted second treating agent solution for polyester staple fiber spunlace (hereinafter also referred to as a diluted second treating agent solution). The second treating agent may be stored or distributed in the form of a diluted second treating agent solution. This configuration improves mixability when diluted with a solvent or when mixed with the first treating agent at the time of use, and also improves the stability of the composition. The solvent may be one of those exemplified in the first embodiment.

[0083] <Actions and Effects of the Fourth Embodiment> In addition to the effects and advantages of the above-described embodiments, the fourth embodiment has the following effects and advantages.

[0084] (4-1) The second treatment agent of the fourth embodiment contains an organic phosphate ester salt (C) and is used in combination with a first treatment agent containing a fatty acid derivative (A), a fatty acid derivative (B), and optionally a diester (D). This improves the formulation stability and storage stability of the second treatment agent during storage or distribution. Furthermore, by adjusting the mixing ratio with the first treatment agent, the components of the resulting treatment agent can be adjusted. Furthermore, the second treatment agent can be distributed separately from the first treatment agent.

[0085] Fifth Embodiment Next, a fifth embodiment of the polyester staple fiber of the present invention will be described. The polyester staple fibers of this embodiment are treated polyester staple fibers having the treating agent of the first embodiment adhered to their surfaces. Modified polyester staple fibers are obtained by adhering the treating agent to the surfaces of the polyester staple fibers.

[0086] (length of polyester staple fiber) Polyester staple fibers generally include those called staple or short cut, and do not include long fibers generally called filaments. Staple refers to short fibers with a fiber length of approximately 3 cm to 7 cm. Short cut refers to short fibers with a fiber length of 1 cm or less. In other words, polyester staple fibers refer to short fibers with a fiber length of approximately 7 cm or less.

[0087] As will be described later, when a spunlace nonwoven fabric is produced using polyester staple fibers, the fibers constituting the nonwoven fabric may contain the above-mentioned long fibers. In other words, the treatment agent of the present invention is not limited to polyester staple fibers, but may also be applied to long fibers other than polyester staple fibers mixed into the nonwoven fabric.

[0088] (Type of polyester staple fiber) Specific examples of polyester staple fibers include polyethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate isophthalate, and polyether polyester.

[0089] (Treatment agent adhesion treatment) There are no particular restrictions on the proportion of the treatment agent of the first embodiment that is applied to the polyester staple fibers. The treatment agent is preferably a solvent-free treatment agent that is applied to the polyester staple fibers in an amount of 0.1% by mass to 2% by mass, and more preferably 0.3% by mass to 1.2% by mass.

[0090] The treatment agent can be applied to polyester staple fibers by a known method, such as a dipping method, a spraying method, a roller method, or a guide oiling method using a metering pump, using the diluted solution of the second embodiment.

[0091] (Nonwoven fabric manufacturing method) The polyester staple fiber of the present embodiment may be used to produce a nonwoven fabric by the following method. Specifically, the nonwoven fabric can be obtained by the following steps.

[0092] Step 1: A step of attaching the treatment agent of the first embodiment to polyester staple fibers. Step 2: A step of passing the polyester staple fibers to which the treatment agent has been applied in step 1 through a roller carding machine to obtain a roller carded web. Step 2 is also called a carding step.

[0093] Step 3: A step of obtaining a nonwoven fabric by entangling the fibers using a spunlace method in which a high-pressure water jet is sprayed onto the roller-carded web obtained in Step 2. Step 3 is also called the spunlace step.

[0094] By going through the above steps, a nonwoven fabric can be produced. Since the fibers are entangled by the spunlace method, the nonwoven fabric can also be called a spunlace nonwoven fabric. When a two-component treatment agent is used in step 1, a diluted solution of the treatment agent containing a solvent such as water, the first treatment agent of the third embodiment, and the second treatment agent of the fourth embodiment is prepared and applied to the polyester staple fibers. The diluted solution can be prepared, for example, by adding the first treatment agent and the second treatment agent to water.

[0095] When the first and second treatment agents are used in combination, the mixing ratio of each agent can be changed as desired, making it easy to fine-tune the mixing ratio and prepare treatment agents or dilutions that always provide optimal fiber properties or fiber production characteristics, even under different production conditions, such as different production facilities or different climates (temperature, humidity, etc.).

[0096] The ratio of the content of the first treatment agent to the second treatment agent is not particularly limited, but the mass ratio of the nonvolatile components of the first treatment agent to the second treatment agent is preferably 95 / 5 to 5 / 95. By specifying the ratio within this range, operability can be improved.

[0097] To emulsify the treating agents, each treating agent may be mixed with a solvent and stirred using a known stirrer such as a homomixer, homogenizer, colloid mill, or line mixer. The diluted solution obtained as described above can be applied to polyester staple fibers in at least one of the steps of spinning, drawing, and finishing polyester staple fibers, to obtain polyester staple fibers having a treatment agent attached thereto.

[0098] <Actions and Effects of Fifth Embodiment> In addition to the effects and advantages of the above-described embodiments, the fifth embodiment has the following effects and advantages.

[0099] (5-1) The polyester staple fibers are coated with the treatment agent of the first embodiment. Therefore, the antistatic properties and roller card web uniformity of the polyester staple fibers can be improved. The improved antistatic properties of the polyester staple fibers improve the processability of the polyester staple fibers in the carding process. Furthermore, the improved roller card web uniformity of the polyester staple fibers reduces variations in thickness and density in the subsequent spunlace process, enabling the production of a higher-quality nonwoven fabric. Therefore, nonwoven fabrics made using the polyester staple fibers of the present invention can be suitably used in applications such as wet tissues and masks.

[0100] (5-2) Furthermore, in the case of a multi-dose formulation, the first and second processing agents are added to a solvent immediately before use to prepare the formulation, thereby improving formulation stability and storage stability. [Example]

[0101] Examples will be given below to more specifically illustrate the configuration and effects of the present invention, but the present invention is not limited to these examples. In the following examples and comparative examples, % means % by mass, and parts means parts by mass.

[0102] Test Category 1 (Preparation of treatment agent for polyester staple fiber spunlace) (Example 1-1) 950 g of water was heated to 50°C, and while stirring, 3.5 g of a compound (A-1) in which 3 moles of EO were added to 1 mole of linoleic acid as the fatty acid derivative (A), 16.5 g of a compound (B-1) in which 3 moles of EO were added to 1 mole of oleic acid as the fatty acid derivative (B), 20 g of undecyl phosphate ester potassium salt (C-1) as the organic phosphate ester salt (C), 2 g of polyoxyethylene (mass average molecular weight 200) dioleate (D-1) as the diester (D), and 1 g of polyoxyethylene (mass average molecular weight 200) dioleate (D-1) were added. A 5% by mass aqueous solution of the treatment agent for polyester staple fiber spunlace of Example 1 was obtained by adding and mixing 0.5 g of ethylene (mass average molecular weight 800) dioleate (D-2), and as other components (E), 1.5 g of compound (E-1) in which 9 moles of EO and 9 moles of PO were randomly added to 1 mole of castor oil, 5 g of compound (E-2) in which 7 moles of EO and 3 moles of PO were randomly added to 1 mole of castor oil, and 1 g of compound (E-3) in which 5 moles of EO and 5 moles of PO were randomly added to 1 mole of hydrogenated castor oil.

[0103] (Examples 1-2 to 1-20, Comparative Examples 1 to 5) The treating agents of Examples 1-2 to 1-20 and Comparative Examples 1 to 5 were prepared in the same manner as in Example 1 using the components shown in Table 1.

[0104] The type and content of the fatty acid derivative (A), the type and content of the fatty acid derivative (B), the type and content of the organic phosphate ester salt (C), the type and content of the diester (D), the type and content of the other component (E), and the mass ratio of the fatty acid derivative (A) to the fatty acid derivative (B) in each example of the treatment agent are shown in the "Fatty acid derivative (A)" column, the "Fatty acid derivative (B)" column, the "Organic phosphate ester salt (C)" column, the "Diester (D)" column, the "Other component (E)" column, and the "Am / Bm" column in Table 1, respectively.

[0105] [Table 1]

[0106] Details of the fatty acid derivative (A), fatty acid derivative (B), organic phosphate ester salt (C), diester (D), and other component (E) listed in Table 1 are as follows. <Fatty acid derivative (A)> As the fatty acid derivatives (A), A-1 to A-5 shown in Table 2 below were used.

[0107] The type of fatty acid derivative (A) and the mass proportion of the oxyalkylene group in the molecular structure are shown in Table 2 in the columns "Type of fatty acid derivative (A)" and "Mass proportion of oxyalkylene group," respectively.

[0108] [Table 2]

[0109] <Fatty acid derivative (B)> As the fatty acid derivatives (B), B-1 to B-5 shown in Table 3 below were used. The type of fatty acid derivative (B) and the mass proportion of the oxyalkylene group in the molecular structure are shown in Table 3 in the columns "Type of fatty acid derivative (B)" and "Mass proportion of oxyalkylene group", respectively.

[0110] [Table 3]

[0111] <Organophosphate ester salts (C)> As the organic phosphate ester salts (C), C-1 to C-6 shown in Table 4 below were used. The alkyl group linearity ratio, alkyl group carbon number, acid value, and P nuclear NMR integral ratio of the organic phosphate ester salt (C) are shown in the "Alkyl group linearity ratio," "Alkyl group carbon number," "Acid value," and "P nuclear NMR integral ratio" columns in Table 4. In Table 4, "mono-form," "di-form," and "poly-form" refer to "monoester form," "diester form," and "diphosphate ester form," respectively. The P nuclear NMR integral ratio can be measured by a known method.

[0112] [Table 4]

[0113] <Diester (D)> D-1: Polyoxyethylene (mass average molecular weight 200) dioleate D-2: Polyoxyethylene (mass average molecular weight 800) dioleate D-3: Polyoxyethylene (mass average molecular weight 400) dilaurate D-4: Polyoxyethylene (mass average molecular weight 600) dilaurate <Other ingredients (E)> E-1: A compound in which 9 moles of EO and 9 moles of PO are randomly added to 1 mole of castor oil. E-2: A compound in which 7 moles of EO and 3 moles of PO are randomly added to 1 mole of castor oil. E-3: A compound in which 5 moles of EO and 5 moles of PO are randomly added to 1 mole of hydrogenated castor oil. E-4: A compound in which 9 moles of EO and 9 moles of PO are randomly added to 1 mole of hydrogenated castor oil. E-5: Sodium salt of secondary alkanesulfonic acid having 11 to 14 carbon atoms E-6: Lauryl alcohol E-7: Oleic acid E-8: Potassium octanoate E-9: an ester compound obtained by dehydration condensation of 1 mole of sebacic acid with 0.1 mole of polyoxyethylene polyoxypropylene glycol (random polymer: mass average molecular weight 13,000, EO component ratio 75% by mass), 0.5 mole of polyethylene glycol (mass average molecular weight 600), and 0.4 mole of polyethylene glycol (mass average molecular weight 400). E-10: Propylene glycol E-11: Ethylene glycol monobutyl ether phosphate ester potassium salt E-12: Polyoxyethylene (mass average molecular weight 400) monolaurate Test Category 2 (Preparation of polyester staple fiber treated cotton) A 5% by mass aqueous solution of the treatment agent for polyester staple fiber spunlace prepared in Test Section 1 was applied to polyester staple fibers (fineness 1.5 dtex, fiber length 38 mm) by spray oiling so that the amount of non-volatile matter of the treatment agent adhered to them was 0.14% by mass. The raw cotton with the treatment agent applied was then dried in a hot air dryer at 80°C for 2 hours, and then conditioned overnight in an atmosphere at 25°C and 40% RH. The conditioned cotton was used as polyester staple fiber treated cotton (hereinafter also referred to as treated cotton).

[0114] Test category 3 (antistatic) Five grams of the treated cotton was conditioned for 24 hours in a thermostatic chamber at 20°C and 45% RH, and then the electrical resistance (Ω) was measured using an electrical resistance meter (SM-5E model, manufactured by Toa Denpa Kogyo Co., Ltd.) and evaluated according to the following criteria. The results are shown in the "Antistatic property" column of Table 1.

[0115] Evaluation criteria for anti-static properties 3 (Good): Surface resistance is 1.0 x 10 9 Less than Ω 2 (Acceptable): Surface resistance is 1.0 x 10 9 Ω or more 1.0×10 10 Less than Ω 1 (unacceptable): Surface resistance is 1.0 x 10 10 Ω or more Test Section 4 (Roller Card Web Uniformity) 20 g of the treated cotton was conditioned for 24 hours in a temperature-controlled room at 20°C and 65% RH, and then subjected to a known roller carding machine. The texture of the discharged roller-carded web was evaluated visually according to the following criteria. The results are shown in the "Web uniformity" column of Table 1.

[0116] Roller card web uniformity evaluation criteria 4 (Excellent): The roller card web has no disturbance in its formation and has a very good appearance.

[0117] 3 (Good): The roller card web has little formation disorder and has a good appearance. 2 (Acceptable): There is some disturbance in the roller card web formation. 1 (Unacceptable): Disorders are observed in the roller card web formation.

[0118] Test category 5 (anti-foaming) 15 g of the treated cotton was placed in 150 g of water, and after 2 hours, the treated cotton was squeezed using a conventional hand juicer. 10 g of the squeezed liquid was placed in a 25 mL measuring cylinder with a stopper and vigorously shaken for 30 seconds. After leaving it to stand for 5 minutes, the height from the water surface to the top of the foam was measured and evaluated according to the following criteria. The results are shown in the "Foam-suppressing ability" column in Table 1.

[0119] ·Evaluation criteria for foam suppression 3 (Good): Foaming less than 3 mm 2 (Acceptable): Foaming is 3mm or more but less than 10mm 1 (Not acceptable): Foaming is 10mm or more Test category 6 (hydrophilic) 5 g of the treated cotton was placed in a 3 g metal basket and placed in 1 L of water. The time it took for the treated cotton to be completely immersed in water was measured and evaluated according to the following criteria. The results are shown in the "Hydrophilicity" column in Table 1.

[0120] Hydrophilicity evaluation criteria 3 (Good): Complete immersion in water for less than 5 seconds 2 (Acceptable): Time until complete immersion in water is between 5 and 10 seconds 1 (Not acceptable): Complete immersion in water for 10 seconds or more Test Category 7 (Emulsion Stability) 20 g of a 5% by mass aqueous solution of each treatment agent was placed in an 18 mm diameter test tube and allowed to stand in a thermostatic chamber at 20°C. After 24 hours, the condition of the aqueous solution was visually inspected and evaluated according to the following criteria. The results are shown in the "Emulsion Stability" column in Table 1.

[0121] ·Evaluation criteria for emulsion stability 3 (Good): Uniform with no sedimentation or separation. 2 (Fair): No precipitation is observed, but separation has occurred.

[0122] 1 (Unacceptable): Precipitation has occurred and the mixture is inhomogeneous. Test Section 8 (Preparation of diluted solution of first treatment agent for two-component treatment agent) (Diluted first treatment agent (I-1) to (I-20)) Each component was weighed out and stirred and mixed to obtain the content ratio shown in Table 5, to prepare diluted first treatment agent solutions for polyester staple fiber spunlace (diluted first treatment agent solutions (I-1) to (I-20)).

[0123] The type and content of fatty acid derivative (A), type and content of fatty acid derivative (B), type and content of diester (D), type and content of other component (E), and content of water in the first treatment agent diluted solutions (I-1) to (I-20) are as shown in the "Fatty acid derivative (A)" column, "Fatty acid derivative (B)" column, "Diester (D)" column, "Other component (E)" column, and "Solvent" column in Table 5, respectively.

[0124] [Table 5]

[0125] Test Section 9 (Preparation of diluted solution of the second treatment agent of two-component treatment agents) Each component was weighed out and stirred and mixed to obtain the content ratios shown in Table 6, to prepare diluted solutions of the second treatment agent for polyester staple fiber spunlace (diluted solutions of the second treatment agent (II-1) to (II-6)).

[0126] The type and content of the organic phosphate ester salt (C) and the content of water in the diluted second treatment agent solutions (II-1) to (II-6) are shown in the "Organic phosphate ester salt (C)" and "Solvent" columns of Table 6, respectively.

[0127] [Table 6]

[0128] Test Section 10 (Evaluation of formulation stability of diluted first and second treatment agents) 10 mL of each of the diluted first and second treatment agents prepared in each example was placed in a test tube, and the stability was evaluated visually according to the following criteria. The results are shown in the "Formulation stability" column of Tables 5 and 6.

[0129] -Evaluation criteria for formulation stability 2 (Acceptable): If there is no separation or precipitate immediately after preparation 1 (Not acceptable): If separation or precipitation is observed immediately after preparation Test Section 11 (Preparation of diluted treatment solution from diluted first treatment solution and diluted second treatment solution) Example 2-1 The second treatment agent diluted solution (II-1) shown in Table 6 was added to half the prescribed amount of water heated to approximately 50°C with stirring until completely dissolved. After dissolution, the first treatment agent diluted solution (I-1) shown in Table 5 was added with stirring until completely dissolved. After dissolution, heating was stopped, and the remaining half of the water at approximately 25°C was added all at once and stirred until uniform, yielding a 5% by mass aqueous solution of the treatment agent diluted solution of Example 2-1.

[0130] (Examples 2-2 to 2-20) In the same manner as in Example 2-1, the diluted first treatment agent solution shown in Table 5 and the diluted second treatment agent solution shown in Table 6 were mixed to prepare diluted treatment agent solutions for each example.

[0131] The type and content of the diluted first treatment agent and the type and content of the diluted second treatment agent are shown in the "Diluted first treatment agent" and "Diluted second treatment agent" columns of Table 7, respectively.

[0132] [Table 7]

[0133] Test Category 12 (Evaluation of diluted two-component treatment solutions) The diluted treatment solutions of each example, such as Example 2-1, were evaluated for antistatic properties, roller card web uniformity, anti-foaming properties, hydrophilicity, and emulsion stability in the same manner as for the treatment solution of Example 1-1. The results are shown in the "Antistatic Properties," "Web Uniformity," "Anti-foaming Properties," "Hydrophilicity," and "Emulsion Stability" columns of Table 7.

[0134] The results in the above table show that the present invention can improve the antistatic properties, roller card web uniformity, foam suppression, and hydrophilicity of fibers to which a treatment agent is applied, as well as the emulsion stability of diluted treatment agents.

Claims

1. A treating agent for polyester staple fiber spunlace, comprising the following fatty acid derivative (A), the following fatty acid derivative (B), and an organic phosphate ester salt (C). Fatty acid derivative (A): an alkylene oxide adduct of at least one selected from linoleic acid and linolenic acid. Fatty acid derivative (B): an alkylene oxide adduct of at least one selected from oleic acid and stearic acid.

2. 2. The treating agent for polyester staple fiber spunlace according to claim 1, wherein the mass proportion of oxyalkylene groups in the molecular structures of the fatty acid derivative (A) and the fatty acid derivative (B) is 50 mass % or less, respectively.

3. The treatment agent for polyester staple fiber spunlace according to claim 1, wherein the mass ratio Am / Bm is 0.01 or more and 0.4 or less, where Am is the mass of the fatty acid derivative (A) in the treatment agent for polyester staple fiber spunlace and Bm is the mass of the fatty acid derivative (B) in the treatment agent for polyester staple fiber spunlace.

4. 2. The treating agent for polyester staple fiber spunlace according to claim 1, wherein the organic phosphate ester salt (C) is a salt of a phosphate ester having an alkyl group having 11 to 13 carbon atoms.

5. 2. The treatment agent for polyester staple fiber spunlace according to claim 1, wherein the non-volatile components of the treatment agent for polyester staple fiber spunlace contain the fatty acid derivative (A) and the fatty acid derivative (B) in a total amount of 30% by mass or more and 70% by mass or less, and the organic phosphate ester salt (C) in a total amount of 10% by mass or more and 60% by mass or less.

6. The treating agent for polyester staple fiber spunlace according to claim 1, further comprising the following diester (D): Diester (D): A diester of polyethylene glycol having a molecular weight of 200 to 800 and a monovalent fatty acid having 12 to 20 carbon atoms.

7. 7. The treatment agent for polyester staple fiber spunlace according to claim 6, wherein the non-volatile components of the treatment agent for polyester staple fiber spunlace contain the fatty acid derivative (A) and the fatty acid derivative (B) in a total amount of 30% by mass or more and 70% by mass or less, the organic phosphate ester salt (C) in an amount of 10% by mass or more and 60% by mass or less, and the diester (D) in an amount of 2% by mass or more and 10% by mass or less.

8. A diluted solution of a treatment agent for polyester staple fiber spunlace, comprising the treatment agent for polyester staple fiber spunlace according to any one of claims 1 to 7 and water.

9. A first treating agent for polyester staple fiber spunlace to be used in combination with a second treating agent for polyester staple fiber spunlace containing an organic phosphate ester salt (C), A first treatment agent for polyester staple fiber spunlace, comprising the following fatty acid derivative (A), the following fatty acid derivative (B), and optionally the following diester (D). Fatty acid derivative (A): an alkylene oxide adduct of at least one selected from linoleic acid and linolenic acid. Fatty acid derivative (B): an alkylene oxide adduct of at least one selected from oleic acid and stearic acid. Diester (D): A diester of polyethylene glycol having a molecular weight of 200 to 800 and a monovalent fatty acid having 12 to 20 carbon atoms.

10. A second treating agent for polyester staple fiber spunlace to be used in combination with a first treating agent for polyester staple fiber spunlace, the second treating agent containing the following fatty acid derivative (A), the following fatty acid derivative (B), and optionally the following diester (D), A second treatment agent for polyester staple fiber spunlace, comprising an organic phosphate ester salt (C). Fatty acid derivative (A): an alkylene oxide adduct of at least one selected from linoleic acid and linolenic acid. Fatty acid derivative (B): an alkylene oxide adduct of at least one selected from oleic acid and stearic acid. Diester (D): A diester of polyethylene glycol having a molecular weight of 200 to 800 and a monovalent fatty acid having 12 to 20 carbon atoms.

11. A polyester staple fiber having the treating agent for polyester staple fiber spunlace according to any one of claims 1 to 7 adhered thereto.

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