Synthetic fiber treating agent and synthetic fiber

Abstract

To enhance strength and electrostatic resistance of a synthetic fiber.SOLUTION: The synthetic fiber treating agent comprises an amino-modified silicone (A) and a glycerin derivative (B), the glycerin derivative (B) comprising at least one ester compound selected from the group consisting of a first ester compound (B1) that is a polyoxyalkylene castor oil ether derivative, a second ester compound (B2) that is a polyoxyalkylene hardened castor oil ether derivative, and a third ester compound (B3) that is a polyoxyalkylene glyceryl ether derivative.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a treating agent for synthetic fibers and synthetic fibers. [Background technology]

[0002] A commonly used method for producing carbon fibers involves spinning a fibrous material and then calcining the material, and this fibrous material is called a carbon fiber precursor. As a carbon fiber precursor, a carbon fiber precursor treatment agent adhered to the surface of a fibrous material such as a polymer may be used. Such a treatment agent is used for purposes such as improving the handleability of the carbon fiber precursor in various steps of producing carbon fiber. As in this example, various synthetic fiber treatment agents that can improve the handleability of synthetic fibers may be used in the handling of synthetic fibers.

[0003] For example, Japanese Patent No. 7098210 (Patent Document 1) discloses a treatment agent for carbon fiber precursors containing a smoothing agent containing an ester compound that is a glycerin derivative. According to the invention described in Patent Document 1, it is possible to reduce the fluff of the flame-resistant fiber after the carbon fiber precursor has been flame-resistant treated. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7098210 Summary of the Invention [Problem to be solved by the invention]

[0005] The invention described in Patent Document 1 leaves room for improvement in terms of the strength and antistatic properties of the synthetic fibers treated with the treating agent.

[0006] Therefore, it is desired to realize a synthetic fiber treatment agent that can improve the strength and antistatic properties of synthetic fibers compared to the prior art, and synthetic fibers to which the synthetic fiber treatment agent is applied. [Means for solving the problem]

[0007] The synthetic fiber treatment agent of the present invention contains an amino-modified silicone (A) and a glycerin derivative (B), wherein the glycerin derivative (B) is a first ester compound (B1) which is an ester compound of a polyoxyalkylene castor oil ether and at least one compound selected from the group consisting of a carboxylic acid, a hydroxy acid, an alkylene oxide adduct of a hydroxy acid, and a polymer of a hydroxy acid; and an ester compound of a polyoxyalkylene hydrogenated castor oil ether and at least one compound selected from the group consisting of a carboxylic acid, a hydroxy acid, an alkylene oxide adduct of a hydroxy acid, and a polymer of a hydroxy acid. and a third ester compound (B3) which is an ester compound of a polyoxyalkylene glyceryl ether and at least one hydroxy acid derivative selected from the group consisting of a carboxylic acid-hydroxy acid ester and a hydroxy acid multimer, wherein the carboxylic acid-hydroxy acid ester is an ester compound of a carboxylic acid and at least one compound selected from the group consisting of a hydroxy acid, an alkylene oxide adduct of a hydroxy acid, and a hydroxy acid multimer.

[0008] This configuration provides a synthetic fiber treatment agent that can improve the strength and antistatic properties of synthetic fibers compared to conventional techniques.

[0009] In one embodiment of the treating agent for synthetic fibers according to the present invention, the proportion of polyoxyethylene groups in the polyoxyalkylene groups in the glycerin derivative (B) is preferably 99 mass % or more.

[0010] This configuration tends to reduce friction between the synthetic fibers treated with the synthetic fiber processing agent and the metal, facilitating smooth winding of the synthetic fibers.

[0011] In one embodiment of the treating agent for synthetic fibers according to the present invention, the glycerin derivative (B) preferably contains at least one ester compound selected from the group consisting of the first ester compound (B1), the second ester compound (B2), and a specific third ester compound (B3a), which is the third ester compound (B3) having a content of hydroxy acid derivative residues per mole of polyoxyalkylene glyceryl ether residues of 2.5 moles or more and 3.0 moles or less.

[0012] This configuration improves the bundling ability of the synthetic fibers to which the synthetic fiber treatment agent has been applied, facilitating smooth winding of the synthetic fibers.

[0013] In one embodiment of the treating agent for synthetic fibers according to the present invention, the glycerin derivative (B) preferably contains carboxylic acid residues, and the proportion of residues derived from monocarboxylic acids among the carboxylic acid residues is preferably 99 mass % or more.

[0014] According to this configuration, the synthetic fibers to which the synthetic fiber processing agent has been applied are less likely to fuse together, and therefore the synthetic fibers wound on a roll or the like can be more smoothly unwound.

[0015] In one embodiment of the treatment agent for synthetic fibers according to the present invention, the proportion of the amino-modified silicone (A) relative to the total mass of the amino-modified silicone (A) and the glycerin derivative (B) is preferably 5 mass% or more and 98 mass% or less.

[0016] According to this configuration, the strength and antistatic properties of the synthetic fibers to which the synthetic fiber treating agent has been applied are further improved.

[0017] In one embodiment, the treating agent for synthetic fibers according to the present invention preferably further contains at least one cationic compound (C) selected from the group consisting of phosphonium salts and ammonium salts.

[0018] According to this configuration, the antistatic properties of the synthetic fibers to which the synthetic fiber treating agent has been applied are further improved.

[0019] In one embodiment of the treatment agent for synthetic fibers according to the present invention, it is preferred that, relative to the total mass of the amino-modified silicone (A), the glycerin derivative (B), and the cationic compound (C), the proportion of the amino-modified silicone (A) is from 8.0 mass% to 94.5 mass%, the proportion of the glycerin derivative (B) is from 5.0 mass% to 90 mass%, and the proportion of the cationic compound (C) is from 0.5 mass% to 5.0 mass%.

[0020] According to this configuration, the antistatic properties of the synthetic fibers to which the synthetic fiber treating agent has been applied are further improved.

[0021] The synthetic fiber according to the present invention is characterized in that the above-mentioned synthetic fiber treating agent is adhered to a fiber material.

[0022] This configuration provides a synthetic fiber with improved strength and antistatic properties compared to the prior art.

[0023] In one aspect of the synthetic fiber according to the present invention, the fiber material is preferably a carbon fiber precursor.

[0024] According to this configuration, a carbon fiber precursor having improved strength and antistatic properties compared to the prior art can be obtained.

[0025] Further features and advantages of the present invention will become more apparent from the following description of exemplary and non-limiting embodiments, which is given with reference to the drawings. DETAILED DESCRIPTION OF THE INVENTION

[0026] DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the accompanying drawings, in which: FIG. 1 is a schematic diagram of a synthetic fiber processing agent according to an embodiment of the present invention;

[0027] [Configuration of treatment agent for synthetic fibers] The synthetic fiber treatment agent according to this embodiment contains an amino-modified silicone (A) and a glycerin derivative (B). Preferably, the synthetic fiber treatment agent according to this embodiment further contains a cationic compound (C).

[0028] When the synthetic fiber treatment agent according to this embodiment is used as a treatment agent for preventing synthetic fibers, it can improve the bundling ability of the synthetic fibers, improve antistatic properties during winding, and reduce friction with metals during winding, thereby improving the efficiency of spinning synthetic fibers. Furthermore, when a carbon fiber precursor is produced using the synthetic fiber treatment agent according to this embodiment, carbon fibers that are high in strength and resistant to fusion can be obtained.

[0029] (amino-modified silicone) Amino-modified silicone (A) is a compound in which an amino group has been introduced into the end of the silicone main chain, the side chain, or both. When an amino group is introduced into the end of the silicone main chain, the amino group may be introduced into both ends, or into only one end. The amino group introduced is arbitrary and may be a monoamine, diamine, amino polyether, or the like. Note that when the end group is not modified, the end group may be an alkyl group (such as a methyl group), an alkoxy group (such as a methoxy group), a hydroxy group, or the like.

[0030] Amino-modified silicone (A) has a kinematic viscosity of 50 mm at 25°C. 2 / s or more 5000mm 2 The kinematic viscosity of the amino-modified silicone (A) can be measured with a Cannon-Fenske viscometer.

[0031] The amino-modified silicone (A) can be identified by its amino equivalent (g / mol) calculated from the total amine value (KOH-mg / g) measured by accurately weighing 1 g into a mixed solution of 60 mL of acetone and 20 mL of normal hexane and titrating it with a perchloric acid solution of known concentration. The amino equivalent of the amino-modified silicone can be 1,000 g / mol or more and 15,000 g / mol or less.

[0032] (glycerin derivatives) The glycerin derivative (B) contains at least one ester compound selected from the group consisting of the following first ester compound (B1), second ester compound (B2), and third ester compound (B3).

[0033] The first ester compound (B1) is an ester compound of a polyoxyalkylene castor oil ether and at least one compound (hereinafter referred to as an acid compound) selected from the group consisting of carboxylic acids, hydroxy acids, alkylene oxide adducts of hydroxy acids, and polymers of hydroxy acids.

[0034] The polyoxyalkylene group in the first ester compound (B1) is not limited and may be a polyoxyethylene group, a polyoxypropylene group, or the like. The polyoxyalkylene group may be of one type or multiple types. When multiple types of polyoxyalkylene groups are present, the multiple types of polyoxyalkylene groups may be present randomly (random adduct) or in blocks (block adduct). The polyoxyalkylene group preferably contains a polyoxyethylene group. It is particularly preferred that the proportion of polyoxyethylene groups in the polyoxyalkylene groups in the first ester compound (B1) is 99% by mass or more, since this suppresses friction between synthetic fibers and metals. The polyoxyalkylene group in the first ester compound (B1) may be a polyoxyalkylene group in a polyoxyalkylene castor oil ether residue or, when the acid compound residue contains an alkylene oxide adduct residue of a hydroxy acid, a polyoxyalkylene group in the residue.

[0035] The number of polyoxyalkylene groups added to the first ester compound (B1) is not particularly limited, but may be, for example, 5 to 60 moles per mole of the first ester compound (B1). When the first ester compound (B1) contains multiple types of polyoxyalkylene groups, the total number of all polyoxyalkylene groups may be within the above range.

[0036] The acid compound preferably contains a carboxylic acid, more preferably a monocarboxylic acid. That is, the first ester compound (B1) preferably contains a carboxylic acid residue. It is particularly preferable that the proportion of residues derived from the monocarboxylic acid among the carboxylic acid residues is 99 mass% or more in terms of preventing fusion of the carbon fibers.

[0037] When the acid compound contains a carboxylic acid, the carboxylic acid may be, but is not limited to, isostearic acid (monovalent), lauric acid (monovalent), oleic acid (monovalent), 2-ethylhexanoic acid (monovalent), adipic acid (divalent), maleic acid (divalent), succinic acid (divalent), terephthalic acid (divalent), sebacic acid (divalent), etc. When the acid compound contains a hydroxy acid, the hydroxy acid may be, but is not limited to, lactic acid, 3-hydroxyhexanoic acid, 2-hydroxydecanoic acid, 12-hydroxystearic acid, ricinoleic acid, etc. When the acid compound contains an alkylene oxide adduct of a hydroxy acid, the alkylene oxide adduct may be, but is not limited to, the alkylene oxide adducts of the hydroxy acids listed above. The number of alkylene oxides added in the adduct is not limited, but may be, for example, 5 to 10 moles per mole of the adduct. When the acid compound contains a hydroxy acid polymer, it may be, but is not limited to, a polymer of the hydroxy acid exemplified above. The degree of polymerization of the polymer is not particularly limited, but may be, for example, a trimer or more and a hexamer or less.

[0038] As an example of the first ester compound (B1), an ester compound of polyoxyethylene castor oil ether (an example of a polyoxyalkylene castor oil ether) and lauric acid (an example of a carboxylic acid) is shown in Formula 1. However, the structure of the ester compound of polyoxyethylene castor oil ether and lauric acid is not limited to the structure of Formula 1. [ka]

[0039] Formula 1 shows an ester compound obtained by reacting polyoxyethylene castor oil ether and lauric acid in a molar ratio of 1:3. That is, in the example of Formula 1, all of the hydroxy groups of the polyoxyethylene castor oil ether are converted to ester bonds. However, in this embodiment, the first ester compound (B1) may have a hydroxy group derived from the hydroxy group of the polyoxyalkylene castor oil ether. That is, the ratio of the polyoxyalkylene castor oil ether residue to the acid compound residue in the first ester compound (B1) is not limited.

[0040] The second ester compound (B2) is an ester compound of a polyoxyalkylene hydrogenated castor oil ether and at least one compound (hereinafter referred to as an acid compound) selected from the group consisting of carboxylic acids, hydroxy acids, alkylene oxide adducts of hydroxy acids, and polymers of hydroxy acids.

[0041] The polyoxyalkylene group in the second ester compound (B2) is not limited and may be a polyoxyethylene group, a polyoxypropylene group, or the like. The polyoxyalkylene group may be of one type or multiple types. When multiple types of polyoxyalkylene groups are present, the multiple types of polyoxyalkylene groups may be present randomly (random adduct) or in blocks (block adduct). The polyoxyalkylene group preferably contains a polyoxyethylene group. It is particularly preferred that the proportion of polyoxyethylene groups in the polyoxyalkylene groups in the second ester compound (B2) is 99% by mass or more, since this suppresses friction between synthetic fibers and metals. The polyoxyalkylene group may be present in the second ester compound (B2) as a polyoxyalkylene group in a polyoxyalkylene hydrogenated castor oil ether residue or as a polyoxyalkylene group in the residue when the acid compound residue contains an alkylene oxide adduct residue of a hydroxy acid.

[0042] The number of polyoxyalkylene groups added to the second ester compound (B2) is not particularly limited, but may be, for example, 5 to 60 moles per mole of the second ester compound (B2). When the second ester compound (B2) contains multiple types of polyoxyalkylene groups, the total number of all polyoxyalkylene groups may be within the above range.

[0043] The acid compound preferably contains a carboxylic acid, more preferably a monocarboxylic acid. That is, the second ester compound (B2) preferably contains a carboxylic acid residue. It is particularly preferable that the proportion of residues derived from the monocarboxylic acid among the carboxylic acid residues is 99 mass% or more in terms of preventing fusion of the carbon fibers.

[0044] When the acid compound contains a carboxylic acid, the carboxylic acid may be, but is not limited to, isostearic acid (monovalent), lauric acid (monovalent), oleic acid (monovalent), 2-ethylhexanoic acid (monovalent), adipic acid (divalent), maleic acid (divalent), succinic acid (divalent), terephthalic acid (divalent), sebacic acid (divalent), etc. When the acid compound contains a hydroxy acid, the hydroxy acid may be, but is not limited to, lactic acid, 3-hydroxyhexanoic acid, 2-hydroxydecanoic acid, 12-hydroxystearic acid, ricinoleic acid, etc. When the acid compound contains an alkylene oxide adduct of a hydroxy acid, the alkylene oxide adduct may be, but is not limited to, the alkylene oxide adducts of the hydroxy acids listed above. The number of alkylene oxides added in the adduct is not limited, but may be, for example, 5 to 10 moles per mole of the adduct. When the acid compound contains a hydroxy acid polymer, it may be, but is not limited to, a polymer of the hydroxy acid exemplified above. The degree of polymerization of the polymer is not particularly limited, but may be, for example, a trimer or more and a hexamer or less.

[0045] As an example of the second ester compound (B2), an ester compound of polyoxyethylene hydrogenated castor oil ether (an example of polyoxyalkylene hydrogenated castor oil ether) and oleic acid (an example of a carboxylic acid) is shown in Formula 2. However, the structure of the ester compound of polyoxyethylene hydrogenated castor oil ether and oleic acid is not limited to the structure of Formula 2. [ka]

[0046] In the second ester compound (B2), the ratio of the polyoxyalkylene hydrogenated castor oil ether residue to the acid compound residue is not limited, and therefore the second ester compound (B2) may have a hydroxy group derived from the hydroxy group of the polyoxyalkylene hydrogenated castor oil ether.

[0047] The third ester compound (B3) is an ester compound of a polyoxyalkylene glyceryl ether and at least one hydroxy acid derivative selected from the group consisting of a carboxylic acid-hydroxy acid ester and a hydroxy acid polymer, where the carboxylic acid-hydroxy acid ester is an ester compound of a carboxylic acid and at least one compound selected from the group consisting of a hydroxy acid, an alkylene oxide adduct of a hydroxy acid, and a hydroxy acid polymer.

[0048] In the third ester compound (B3), the ratio of polyoxyalkylene glyceryl ether residues to hydroxy acid derivative residues is not limited. Therefore, the third ester compound (B3) may have a hydroxy group derived from a polyoxyalkylene glyceryl ether. However, in the third ester compound (B3), the content of hydroxy acid derivative residues per mole of polyoxyalkylene glyceryl ether residues is preferably 2.5 moles or more and 3.0 moles or less, since this tends to improve the bundling ability of synthetic fibers. Hereinafter, a third ester compound (B3) that meets this requirement will be referred to as a specific third ester compound (B3a) for distinction.

[0049] The polyoxyalkylene group in the third ester compound (B3) is not limited and may be a polyoxyethylene group, a polyoxypropylene group, or the like. The polyoxyalkylene group may be of one type or multiple types. When multiple types of polyoxyalkylene groups are present, the multiple types of polyoxyalkylene groups may be present randomly (random adduct) or in blocks (block adduct). The polyoxyalkylene group preferably contains a polyoxyethylene group. It is particularly preferred that the proportion of polyoxyethylene groups in the polyoxyalkylene groups in the third ester compound (B3) is 99 mass% or more, since this suppresses friction between synthetic fibers and metals. The polyoxyalkylene group may be present in the third ester compound (B3) as a polyoxyalkylene glyceryl ether residue, or as a polyoxyalkylene group in the residue of a hydroxy acid derivative containing a carboxylic acid-hydroxy acid ester residue and, when the carboxylic acid-hydroxy acid ester residue contains an alkylene oxide adduct residue of a hydroxy acid, as the polyoxyalkylene group in the residue.

[0050] The number of polyoxyalkylene groups added to the third ester compound (B3) is not particularly limited, but may be, for example, 5 to 60 moles per mole of the third ester compound (B3). When the third ester compound (B3) contains multiple types of polyoxyalkylene groups, the total number of all the polyoxyalkylene groups may be within the above range.

[0051] When the hydroxy acid derivative contains a carboxylic acid-hydroxy acid ester, the carboxylic acid constituting the carboxylic acid-hydroxy acid ester preferably contains a monocarboxylic acid. That is, it is preferable that the third ester compound (B3) contains a carboxylic acid-hydroxy acid ester residue, and the carboxylic acid-hydroxy acid ester residue contains a carboxylic acid residue. It is particularly preferable that the proportion of residues derived from monocarboxylic acids among the carboxylic acid residues is 99 mass% or more in terms of preventing fusion of carbon fibers. The carboxylic acid constituting the carboxylic acid-hydroxy acid ester may be, but is not limited to, isostearic acid (monovalent), lauric acid (monovalent), oleic acid (monovalent), 2-ethylhexanoic acid (monovalent), adipic acid (divalent), maleic acid (divalent), succinic acid (divalent), terephthalic acid (divalent), or sebacic acid (divalent).

[0052] When the compound constituting the carboxylic acid-hydroxy acid ester contains a hydroxy acid, the hydroxy acid may be, but is not limited to, lactic acid, 3-hydroxyhexanoic acid, 2-hydroxydecanoic acid, 12-hydroxystearic acid, ricinoleic acid, etc. When the compound constituting the carboxylic acid-hydroxy acid ester contains an alkylene oxide adduct of a hydroxy acid, the alkylene oxide adduct may be, but is not limited to, the alkylene oxide adducts of the hydroxy acids listed above. The number of alkylene oxides added in the adduct is not limited, but may be, for example, 5 to 10 moles per mole of the adduct. When the acid compound contains a hydroxy acid multimer, the acid compound may be, but is not limited to, the hydroxy acid multimers listed above. The degree of polymerization of the multimer is not particularly limited, but may be, for example, a trimer or more and a hexamer or less.

[0053] An example of the third ester compound (B3) is an ester compound of polyoxyethylene glyceryl ether (an example of a polyoxyalkylene glyceryl ether) and a carboxylic acid-hydroxy acid ester, which is an ester compound of oleic acid (an example of a carboxylic acid) and 12-hydroxystearic acid (an example of a hydroxy acid), as shown in Formula 3. However, the structure of the ester compound of polyoxyethylene glyceryl ether and the carboxylic acid-hydroxy acid ester is not limited to the structure of Formula 3. [ka]

[0054] (cationic compounds) The synthetic fiber treatment agent according to this embodiment preferably further contains at least one cationic compound (C) selected from the group consisting of phosphonium salts and ammonium salts. The inclusion of the cationic compound (C) in the synthetic fiber treatment agent is advantageous from the viewpoint of preventing static electricity buildup on the synthetic fibers.

[0055] Examples of phosphonium salts include, but are not limited to, tributylethylphosphonium diethylphosphate and tetrabutylphosphonium dodecylbenzenesulfonate.

[0056] Examples of ammonium salts include, but are not limited to, benzalkonium chloride, benzethonium bromide, stearyltrimethylammonium dimethyl phosphate, and didecyldimethylammonium chloride.

[0057] (Other ingredients) The synthetic fiber treatment agent according to this embodiment may contain components other than the amino-modified silicone (A), the glycerin derivative (B), and the optionally contained cationic compound (C). Examples of such other components include, but are not limited to, preservatives, antistatic agents, antioxidants, ultraviolet absorbers, and antifoaming agents.

[0058] The synthetic fiber treatment agent according to this embodiment may contain silicone compounds other than the amino-modified silicone (A). Examples of such silicone compounds include, but are not limited to, dimethyl silicone and polyether-modified silicone.

[0059] The synthetic fiber treatment agent according to this embodiment may contain a polyoxyalkylene derivative other than the glycerin derivative (B). Such polyoxyalkylene derivatives may include, but are not limited to, alkylene oxide adducts of castor oil, alkylene oxide adducts of hydrogenated castor oil, and alkylene oxide adducts of saturated or unsaturated alcohols.

[0060] (Content of each ingredient) In the synthetic fiber treatment agent according to this embodiment, the proportion of the amino-modified silicone (A) relative to the total mass of the amino-modified silicone (A) and the glycerin derivative (B) is preferably 5% by mass or more and 98% by mass or less. When the proportion of the amino-modified silicone (A) is within this range, when the synthetic fiber treatment agent is applied to the production of carbon fibers, the strength of the resulting carbon fibers tends to be high.

[0061] In the synthetic fiber treatment agent according to this embodiment, it is preferable that, relative to the total mass of the amino-modified silicone (A), the glycerin derivative (B), and the cationic compound (C), the proportion of the amino-modified silicone (A) is 8.0% by mass or more and 94.5% by mass or less, the proportion of the glycerin derivative (B) is 5.0% by mass or more and 90% by mass or less, and the proportion of the cationic compound (C) is 0.5% by mass or more and 5.0% by mass or less. When the proportions of the amino-modified silicone (A), the glycerin derivative (B), and the cationic compound (C) are each within the above ranges, when the synthetic fiber treatment agent is applied to the production of carbon fibers, the strength of the resulting carbon fibers tends to be high.

[0062] Other Embodiments Regarding other configurations, it should be understood that the embodiments disclosed in this specification are illustrative in all respects and that the scope of the present invention is not limited thereby. Those skilled in the art will easily understand that appropriate modifications are possible without departing from the spirit of the present invention. Therefore, other embodiments modified without departing from the spirit of the present invention are naturally included in the scope of the present invention. [Example]

[0063] The present invention will be further described below with reference to examples, but the present invention is not limited to these examples.

[0064] [Preparation of Treatment Agent for Synthetic Fibers] The synthetic fiber treating agents of Examples 1 to 68 and Comparative Examples 1 to 7 shown in Tables 2 to 8 below were obtained by the following method.

[0065] (1) Reagents (1-1) Amino-modified silicone The amino-modified silicones used were amino-modified silicones A-1 to A-8 having the properties shown in Table 1. All of the amino-modified silicones correspond to the amino-modified silicone (A) according to the above embodiment. The kinematic viscosity and amino equivalent weight shown in Table 1 are values ​​measured by the method described in the above embodiment.

[0066] Table 1: Amino-modified silicones [Table 1]

[0067] (1-2) Glycerin derivatives (1-2-1) Primary ester compound The following first ester compounds B1-1 to B1-7 were used as glycerin derivatives corresponding to the first ester compound. All of the first ester compounds correspond to the first ester compound (B1) according to the above embodiment. However, the production methods shown for each first ester compound are only examples, and the results of the examples and comparative examples will not change even if the first ester compound is produced by a method different from the method exemplified below.

[0068] (First ester compound B1-1) Polyoxyethylene castor oil ether was obtained by reacting castor oil with ethylene oxide in a molar ratio of 1:5. Polyoxyethylene castor oil ether was obtained by reacting 3-hydroxyhexanoic acid (a hydroxy acid) in a molar ratio of 1:1, to obtain a first ester compound B1-1.

[0069] (First ester compound B1-2) Castor oil and ethylene oxide were reacted in a molar ratio of 1:10 to obtain polyoxyethylene castor oil ether. 2-Hydroxydecanoic acid and ethylene oxide were reacted in a molar ratio of 1:5 using methanesulfonic acid as an acid catalyst to obtain an ethylene oxide adduct of 2-hydroxydecanoic acid. Polyoxyethylene castor oil ether and ethylene oxide adduct of 2-hydroxydecanoic acid were reacted in a molar ratio of 1:2 to obtain first ester compound B1-2.

[0070] (First ester compound B1-3) Polyoxyethylene castor oil ether was obtained by reacting castor oil with ethylene oxide in a molar ratio of 1:25, and polyoxyethylene castor oil ether was obtained by reacting isostearic acid (a monocarboxylic acid) in a molar ratio of 1:2 to obtain a first ester compound B1-3.

[0071] (First ester compound B1-4) Polyoxyethylene castor oil ether was obtained by reacting castor oil with ethylene oxide in a molar ratio of 1:40. Polyoxyethylene castor oil ether was obtained by reacting adipic acid (a dicarboxylic acid) in a molar ratio of 1:3, to obtain a first ester compound B1-4.

[0072] (First ester compound B1-5) Castor oil, ethylene oxide, and propylene oxide were reacted in a molar ratio of 1:10:10 to obtain a polyoxyalkylene castor oil ether. Ethylene oxide and propylene oxide were added to castor oil in a random manner. An alkylene oxide adduct of 3-hydroxyhexanoic acid was obtained by reacting 3-hydroxyhexanoic acid (a hydroxy acid), ethylene oxide, and propylene oxide in a molar ratio of 1:5:5 using methanesulfonic acid as an acid catalyst. Ethylene oxide and propylene oxide were added to 3-hydroxyhexanoic acid in a random manner. A first ester compound B1-5 was obtained by reacting a polyoxyalkylene castor oil ether with an alkylene oxide adduct of 3-hydroxyhexanoic acid in a molar ratio of 1:2.

[0073] (First ester compound B1-6) Polyoxypropylene castor oil ether was obtained by reacting castor oil with propylene oxide in a molar ratio of 1:10. Polyoxypropylene castor oil ether was obtained by reacting lauric acid (a monocarboxylic acid) in a molar ratio of 1:2, to obtain a first ester compound B1-6.

[0074] (First ester compound B1-7) Castor oil, ethylene oxide, and propylene oxide were reacted in a molar ratio of 1:20:40 to obtain polyoxyalkylene castor oil ether. Ethylene oxide and propylene oxide were added to castor oil in a random manner. Polyoxyalkylene castor oil ether was reacted with a trimer of lactic acid (a hydroxy acid) in a molar ratio of 1:3 to obtain a first ester compound B1-7.

[0075] (1-2-2) Secondary ester compounds The following second ester compounds B2-1 to B2-6 were used as the second ester compounds. All of the second ester compounds correspond to the second ester compound (B2) according to the above embodiment. However, the production methods shown for each second ester compound are only examples, and the results of the examples and comparative examples will not change even if the second ester compound is produced by a method different from the method exemplified below.

[0076] (Second ester compound B2-1) Hydrogenated castor oil and ethylene oxide were reacted in a molar ratio of 1:5 to obtain polyoxyethylene hydrogenated castor oil ether. Polyoxyethylene hydrogenated castor oil ether and 12-hydroxystearic acid (a hydroxy acid) were reacted in a molar ratio of 1:3 to obtain a second ester compound B2-1.

[0077] (Second ester compound B2-2) Hydrogenated castor oil and ethylene oxide were reacted in a molar ratio of 1:20 to obtain polyoxyethylene hydrogenated castor oil ether. Polyoxyethylene hydrogenated castor oil ether and oleic acid (a monocarboxylic acid) were reacted in a molar ratio of 1:2 to obtain a second ester compound B2-2.

[0078] (Second ester compound B2-3) Hydrogenated castor oil was reacted with ethylene oxide in a molar ratio of 1:60 to obtain polyoxyethylene hydrogenated castor oil ether. Polyoxyethylene hydrogenated castor oil ether was reacted with a hexamer of 12-hydroxystearic acid (a hydroxy acid) in a molar ratio of 1:2 to obtain a second ester compound B2-3.

[0079] (Second ester compound B2-4) Hydrogenated castor oil and ethylene oxide were reacted in a molar ratio of 1:25 to obtain polyoxyethylene hydrogenated castor oil ether. Polyoxyethylene hydrogenated castor oil ether and maleic acid (a dicarboxylic acid) were reacted in a molar ratio of 1:1 to obtain a second ester compound B2-4.

[0080] (Second ester compound B2-5) Hydrogenated castor oil, ethylene oxide, and propylene oxide were reacted in a molar ratio of 1:10:5 to obtain a polyoxyalkylene hydrogenated castor oil ether. Ethylene oxide and propylene oxide were added to the hydrogenated castor oil in a random manner. A polyoxyalkylene hydrogenated castor oil ether was reacted with isostearic acid (a monocarboxylic acid) in a molar ratio of 1:1 to obtain a second ester compound B2-5.

[0081] (Second ester compound B2-6) Hydrogenated castor oil and propylene oxide were reacted in a molar ratio of 1:50 to obtain polyoxypropylene hydrogenated castor oil ether. Polyoxypropylene hydrogenated castor oil ether and succinic acid (a dicarboxylic acid) were reacted in a molar ratio of 1:3 to obtain a second ester compound B2-6.

[0082] (1-2-3) Tertiary ester compounds The following third ester compounds B3a-1 to B3a-8 and third ester compounds B3-9 to B3-20 were used as third ester compounds. All of the third ester compounds correspond to the third ester compound (B3) according to the above embodiment, and third ester compounds B3a-1 to B3a-8 correspond to the specific third ester compound (B3a) according to the above embodiment. However, the production methods shown for each third ester compound are only examples, and the results of the examples and comparative examples will not change even if the third ester compound is produced by a method different from the methods exemplified below.

[0083] (Tertiary ester compound B3a-1) Glycerin and ethylene oxide were reacted in a molar ratio of 1:5 to obtain polyoxyethylene glyceryl ether. 2-Ethylhexanoic acid (a monocarboxylic acid) and 3-hydroxyhexanoic acid (a hydroxy acid) were reacted in a molar ratio of 1:1 to obtain a carboxylic acid-hydroxy acid ester. Polyoxyethylene glyceryl ether and a carboxylic acid-hydroxy acid ester were reacted in a molar ratio of 1:3 to obtain a third ester compound B3a-1.

[0084] In the third ester compound B3a-1, the content of 3-hydroxyhexanoic acid residues (hydroxy acid derivative residues) per mole of polyoxyethylene glyceryl ether residue is 3 moles, which corresponds to the molar ratio when polyoxyethylene glyceryl ether and carboxylic acid-hydroxy acid ester are reacted. In the following examples, the content of hydroxy acid derivative residues per mole of polyoxyalkylene glyceryl ether residues in the third ester compound also corresponds to the molar ratio when polyoxyalkylene glyceryl ether and carboxylic acid-hydroxy acid ester are reacted.

[0085] (Tertiary ester compound B3a-2) Glycerin and ethylene oxide were reacted in a molar ratio of 1:20 to obtain polyoxyethylene glyceryl ether. Oleic acid (a monocarboxylic acid) and 12-hydroxystearic acid (a hydroxy acid) were reacted in a molar ratio of 1:1 to obtain a carboxylic acid-hydroxy acid ester. Polyoxyethylene glyceryl ether and a carboxylic acid-hydroxy acid ester were reacted in a molar ratio of 1:3 to obtain a third ester compound B3a-2.

[0086] (Tertiary ester compound B3a-3) Glycerin and ethylene oxide were reacted in a molar ratio of 1:35 to obtain polyoxyethylene glyceryl ether. 12-hydroxystearic acid (a hydroxy acid) and ethylene oxide were reacted in a molar ratio of 1:5 using methanesulfonic acid as an acid catalyst to obtain an ethylene oxide adduct of 12-hydroxystearic acid. Isostearic acid (a monocarboxylic acid) and an ethylene oxide adduct of 12-hydroxystearic acid were reacted in a molar ratio of 1:1 to obtain a carboxylic acid-hydroxy acid ester. Polyoxyethylene glyceryl ether and a carboxylic acid-hydroxy acid ester were reacted in a molar ratio of 1:3 to obtain a third ester compound B3a-3.

[0087] (Tertiary ester compound B3a-4) Glycerin and ethylene oxide were reacted in a molar ratio of 1:50 to obtain polyoxyethylene glyceryl ether, and polyoxyethylene glyceryl ether and a hexamer of 12-hydroxystearic acid (a hydroxy acid) were reacted in a molar ratio of 1:3 to obtain a tertiary ester compound B3a-4.

[0088] (Tertiary ester compound B3a-5) Glycerin and ethylene oxide were reacted in a molar ratio of 1:10 to obtain polyoxyethylene glyceryl ether. Terephthalic acid (a dicarboxylic acid) and 12-hydroxystearic acid (a hydroxy acid) were reacted in a molar ratio of 1:1 to obtain a carboxylic acid-hydroxy acid ester. Polyoxyethylene glyceryl ether and a carboxylic acid-hydroxy acid ester were reacted in a molar ratio of 1:3 to obtain a third ester compound B3a-5.

[0089] (Tertiary ester compound B3a-6) Glycerin and ethylene oxide were reacted in a molar ratio of 1:20 to obtain polyoxyethylene glyceryl ether. Sebacic acid (a dicarboxylic acid) and 12-hydroxystearic acid (a hydroxy acid) were reacted in a molar ratio of 1:1 to obtain a carboxylic acid-hydroxy acid ester. Polyoxyethylene glyceryl ether and a carboxylic acid-hydroxy acid ester were reacted in a molar ratio of 1:3 to obtain a third ester compound B3a-6.

[0090] (Tertiary ester compound B3a-7) Glycerin and ethylene oxide were reacted in a molar ratio of 1:25 to obtain polyoxyethylene glyceryl ether. Maleic acid (a dicarboxylic acid) and ricinoleic acid (a hydroxy acid) were reacted in a molar ratio of 1:1 to obtain a carboxylic acid-hydroxy acid ester. Polyoxyethylene glyceryl ether and a carboxylic acid-hydroxy acid ester were reacted in a molar ratio of 1:3 to obtain a third ester compound B3a-7.

[0091] (Tertiary ester compound B3a-8) Glycerin and ethylene oxide were reacted in a molar ratio of 1:40 to obtain polyoxyethylene glyceryl ether. Adipic acid (a dicarboxylic acid) and 3-hydroxyhexanoic acid (a hydroxy acid) were reacted in a molar ratio of 1:1 to obtain a carboxylic acid-hydroxy acid ester. Polyoxyethylene glyceryl ether and a carboxylic acid-hydroxy acid ester were reacted in a molar ratio of 1:3 to obtain a third ester compound B3a-8.

[0092] (Tertiary ester compound B3-9) Glycerin and ethylene oxide were reacted in a molar ratio of 1:15 to obtain polyoxyethylene glyceryl ether. Oleic acid (a monocarboxylic acid) and 12-hydroxystearic acid (a hydroxy acid) were reacted in a molar ratio of 1:1 to obtain a carboxylic acid-hydroxy acid ester. Polyoxyethylene glyceryl ether and a carboxylic acid-hydroxy acid ester were reacted in a molar ratio of 1:2 to obtain a tertiary ester compound B3-9.

[0093] (Tertiary ester compound B3-10) Glycerin and ethylene oxide were reacted in a molar ratio of 1:45 to obtain polyoxyethylene glyceryl ether. 12-hydroxystearic acid (a hydroxy acid) and ethylene oxide were reacted in a molar ratio of 1:5 using methanesulfonic acid as an acid catalyst to obtain an ethylene oxide adduct of 12-hydroxystearic acid. Isostearic acid (a monocarboxylic acid) and an ethylene oxide adduct of 12-hydroxystearic acid were reacted in a molar ratio of 1:1 to obtain a carboxylic acid-hydroxy acid ester. Polyoxyethylene glyceryl ether and a carboxylic acid-hydroxy acid ester were reacted in a molar ratio of 1:2 to obtain a tertiary ester compound B3-10.

[0094] (Tertiary ester compound B3-11) Glycerin and ethylene oxide were reacted in a molar ratio of 1:5 to obtain polyoxyethylene glyceryl ether. Polyoxyethylene glyceryl ether was reacted with a hexamer of 12-hydroxystearic acid (a hydroxy acid) in a molar ratio of 1:2 to obtain a tertiary ester compound B3-11.

[0095] (Tertiary ester compound B3-12) Glycerin and ethylene oxide were reacted in a molar ratio of 1:20 to obtain polyoxyethylene glyceryl ether. Oleic acid (a monocarboxylic acid) and 12-hydroxystearic acid (a hydroxy acid) were reacted in a molar ratio of 1:1 to obtain a carboxylic acid-hydroxy acid ester. Polyoxyethylene glyceryl ether and a carboxylic acid-hydroxy acid ester were reacted in a molar ratio of 1:1 to obtain a tertiary ester compound B3-12.

[0096] (Tertiary ester compound B3-13) Glycerin and ethylene oxide were reacted in a molar ratio of 1:25 to obtain polyoxyethylene glyceryl ether. Adipic acid (a dicarboxylic acid) and 3-hydroxyhexanoic acid (a hydroxy acid) were reacted in a molar ratio of 1:1 to obtain a carboxylic acid-hydroxy acid ester. Polyoxyethylene glyceryl ether and a carboxylic acid-hydroxy acid ester were reacted in a molar ratio of 1:2 to obtain a tertiary ester compound B3-13.

[0097] (Tertiary ester compound B3-14) Glycerin and ethylene oxide were reacted in a molar ratio of 1:30 to obtain polyoxyethylene glyceryl ether. Maleic acid (a dicarboxylic acid) and ricinoleic acid (a hydroxy acid) were reacted in a molar ratio of 1:1 to obtain a carboxylic acid-hydroxy acid ester. Polyoxyethylene glyceryl ether and a carboxylic acid-hydroxy acid ester were reacted in a molar ratio of 1:2 to obtain a tertiary ester compound B3-14.

[0098] (Tertiary ester compound B3-15) Glycerin, ethylene oxide, and propylene oxide were reacted in a molar ratio of 1:10:10 to obtain a polyoxyalkylene glyceryl ether. Ethylene oxide and propylene oxide were added to glycerin in a random manner. Oleic acid (a monocarboxylic acid) and 12-hydroxystearic acid (a hydroxy acid) were reacted in a molar ratio of 1:1 to obtain a carboxylic acid-hydroxy acid ester. Polyoxyalkylene glyceryl ether and a carboxylic acid-hydroxy acid ester were reacted in a molar ratio of 1:2 to obtain a third ester compound B3-15.

[0099] (Tertiary ester compound B3-16) Glycerin, ethylene oxide, and propylene oxide were reacted in a molar ratio of 1:35:5 to obtain a polyoxyalkylene glyceryl ether. Ethylene oxide and propylene oxide were added to glycerin in a random manner. 2-Ethylhexanoic acid (a monocarboxylic acid) and 3-hydroxyhexanoic acid (a hydroxy acid) were reacted in a molar ratio of 1:1 to obtain a carboxylic acid-hydroxy acid ester. Polyoxyalkylene glyceryl ether and a carboxylic acid-hydroxy acid ester were reacted in a molar ratio of 1:2 to obtain a tertiary ester compound B3-16.

[0100] (Tertiary ester compound B3-17) Glycerin, ethylene oxide, and propylene oxide were reacted in a molar ratio of 1:10:20 to obtain a polyoxyalkylene glyceryl ether. Ethylene oxide and propylene oxide were added to glycerin in a block addition manner, in which propylene oxide and ethylene oxide were added in that order. A polyoxyalkylene glyceryl ether was reacted with a hexamer of 12-hydroxystearic acid (a hydroxy acid) in a molar ratio of 1:1 to obtain a tertiary ester compound B3-17.

[0101] (Tertiary ester compound B3-18) Glycerin, ethylene oxide, and propylene oxide were reacted in a molar ratio of 1:5:35 to obtain a polyoxyalkylene glyceryl ether. Ethylene oxide and propylene oxide were added to glycerin in a random manner. Maleic acid (a dicarboxylic acid) and ricinoleic acid (a hydroxy acid) were reacted in a molar ratio of 1:1 to obtain a carboxylic acid-hydroxy acid ester. Polyoxyalkylene glyceryl ether and a carboxylic acid-hydroxy acid ester were reacted in a molar ratio of 1:2 to obtain a third ester compound B3-18.

[0102] (Tertiary ester compound B3-19) Glycerin and propylene oxide were reacted in a molar ratio of 1:60 to obtain polyoxypropylene glyceryl ether. Adipic acid (a dicarboxylic acid) and 3-hydroxyhexanoic acid (a hydroxy acid) were reacted in a molar ratio of 1:1 to obtain a carboxylic acid-hydroxy acid ester. Polyoxypropylene glyceryl ether and a carboxylic acid-hydroxy acid ester were reacted in a molar ratio of 1:2 to obtain a tertiary ester compound B3-19.

[0103] (Tertiary ester compound B3-20) Glycerin, ethylene oxide, and propylene oxide were reacted in a molar ratio of 1:20:10 to obtain a polyoxyalkylene glyceryl ether. Ethylene oxide and propylene oxide were added to glycerin in a block addition manner, in which ethylene oxide and propylene oxide were added in that order. Adipic acid (a dicarboxylic acid) and 3-hydroxyhexanoic acid (a hydroxy acid) were reacted in a molar ratio of 1:1 to obtain a carboxylic acid-hydroxy acid ester. A polyoxyalkylene glyceryl ether and a carboxylic acid-hydroxy acid ester were reacted in a molar ratio of 1:1 to obtain a third ester compound B3-20.

[0104] (1-3) Cationic compounds The following cationic compounds C-1 to C-6 were used as the cationic compounds. All of these cationic compounds correspond to the cationic compound (C) according to the above embodiment. Cationic compounds C-1 to C-4 are ammonium salts, and cationic compounds C-5 and C-6 are phosphonium salts. C-1: Benzalkonium chloride C-2: Benzethonium bromide C-3: Stearyl trimethylammonium dimethyl phosphate C-4: Didecyldimethylammonium chloride C-5: Tributylethylphosphonium diethylphosphate C-6: Tetrabutylphosphonium dodecylbenzenesulfonate

[0105] (1-4) Other ingredients The following were used as other components. The other components Z-1 and Z-2 were silicone compounds. The kinematic viscosities of the other components Z-1 and Z-2 were measured using a Cannon-Fenske viscometer. Hereinafter, these components will be referred to as silicone compounds Z-1 and Z-2, respectively. Z-1: Kinematic viscosity at 25°C is 350mm 2 / s dimethyl silicone Z-2: Kinematic viscosity at 25°C is 1700mm 2 / s polyether-modified silicone, in which the mass ratio of silicone to polyether is 20:80 and the molar ratio of polyoxyethylene groups to polyoxypropylene groups in the polyether portion is 40:60.

[0106] The other components Z-3 to Z-6 are polyoxyalkylene derivatives. Hereinafter, these components will be referred to as polyoxyalkylene derivatives Z-3 to Z-6, respectively, and their production methods will be described. The production methods shown here are all examples, and the results of the examples and comparative examples will not change even if the polyoxyalkylene derivatives are produced by a method different from the methods exemplified below. Z-3: Polyoxyethylene hydrogenated castor oil obtained by reacting hydrogenated castor oil with ethylene oxide in a molar ratio of 1:20 Z-4: Polyoxyethylene isononyl ether obtained by reacting isononyl alcohol with ethylene oxide in a molar ratio of 1:15 Z-5: Polyoxyethylene dodecyl ether obtained by reacting secondary dodecyl alcohol with ethylene oxide in a molar ratio of 1:9 Z-6: Polyoxyalkylene oleyl ether obtained by reacting oleyl alcohol, ethylene oxide, and propylene oxide in a molar ratio of 1:45:5, in which the ethylene oxide and propylene oxide were added to the oleyl alcohol in a block addition manner in the order of propylene oxide and ethylene oxide.

[0107] (2) Preparation of synthetic fiber treatment agent (Preparation of Example 1) The amino-modified silicone A-5 was 45% by mass, the first ester compound B1-1 was 35% by mass, the cationic compound C-6 was 1% by mass, and the polyoxyalkylene derivative Z-5 was 19% by mass, and the components were weighed out and placed in a beaker. After thoroughly mixing the components, ion-exchanged water was gradually added while stirring to prepare an aqueous solution with a total component concentration of 30% by mass, which was used as the synthetic fiber treatment agent of Example 1.

[0108] (Preparation of Other Examples and Comparative Examples) Except for changing the types and ratios of the reagents to be mixed, the synthetic fiber treatment agents of each example were prepared in the same manner as in Example 1. The preparation conditions for all examples, including Example 1, are shown in Tables 2 to 8 below.

[0109] [Evaluation of Treatment Agents for Synthetic Fibers] (1) Preparation of carbon fiber (1-1) Preparation of fiber materials A copolymer consisting of 95% by mass of acrylonitrile, 3.5% by mass of methyl acrylate, and 1.5% by mass of methacrylic acid with an intrinsic viscosity of 1.80 was dissolved in dimethylacetamide (DMAC) to prepare a spinning dope with a polymer concentration of 21.0% by mass and a viscosity of 500 poise at 60°C. The spinning dope was extruded at a draft ratio of 0.8 from a spinneret with a pore size (inner diameter) of 0.075 mm and 12,000 holes into a coagulation bath of a 70% by mass aqueous solution of DMAC maintained at a spinning bath temperature of 35°C. The coagulated yarn was stretched 5 times in a water washing tank while the solvent was removed, producing a water-swollen acrylic fiber strand (an example of a fiber material).

[0110] (1-2) Preparation of carbon fiber precursor The prepared acrylic fiber strand was oiled by immersion with a 4% ion-exchange aqueous solution of the synthetic fiber treatment agent of each of the Examples and Comparative Examples so that the amount of treatment agent attached was 1 mass % (solvent not included). Thereafter, the acrylic fiber strand to which the treatment agent was attached was subjected to a drying and densification treatment with heated rollers at 150°C, and further subjected to drawing by 1.7 times between heated rollers at 170°C, and then wound around a bobbin to obtain a carbon fiber precursor.

[0111] (1-3) Preparation of carbon fiber A yarn was unwound from the carbon fiber precursor of each of the Examples and Comparative Examples, and subjected to a flame-resistant treatment in an air atmosphere for 1 hour in a flame-resistant furnace having a temperature gradient of 230 to 270°C, and then wound onto a bobbin to obtain a flame-resistant yarn. Further, a yarn was unwound from this flame-resistant yarn, and calcined in a nitrogen atmosphere in a carbonization furnace having a temperature gradient of 300 to 1300°C to convert it into a carbon fiber, which was then wound onto a bobbin to obtain a carbon fiber.

[0112] (2) Evaluation of carbon fiber strength The tensile strength of the carbon fibers in each of the Examples and Comparative Examples was measured in accordance with JIS R 7606: 2000. The measured tensile strength values ​​were classified into the following three levels. A: The tensile strength is 4.5 GPa or more. B: The tensile strength is 3.5 GPa or more and less than 4.5 GPa. C: The tensile strength is less than 3.5 GPa.

[0113] (3) Evaluation of fiber-metal friction For each of the Examples and Comparative Examples, the presence or absence and frequency of yarn breakage in the take-up winder during the production of the carbon fiber precursor were observed. The observation results were classified into the following three levels. A: No yarn breakage occurred up to 24 hours after the start of spinning. B: Two or fewer yarn breakages were observed within 24 hours after the start of spinning, but this did not affect operation. C: Three or more yarn breakages occurred immediately after spinning and within 24 hours, causing operational problems.

[0114] (4) Evaluation of convergence For each of the Examples and Comparative Examples, the bundling state of the acrylic fiber strands when passing through the heated rollers was visually observed, and the results were classified into the following three levels. A: The bundle was well-bundled and no wrapping around the heating roller was observed. B: The threads were slightly loose, but they did not break and did not interfere with operations. C: Many instances of yarn coming apart were observed, causing yarn breakage and hindering operations.

[0115] (5) Evaluation of adhesion prevention For each carbon fiber in the Examples and Comparative Examples, 1 cm test pieces were cut from ten randomly selected locations to obtain ten test pieces. The fusion state of the yarn in each test piece was visually observed, and the number of fusion points was counted. The average number of fusion points in the ten test pieces was then classified into the following three levels. A: There are an average of less than two fused areas per test piece. B: The number of fused parts is two or more but less than seven on average per test piece. C: There are an average of 7 or more fused locations per test piece.

[0116] (6) Evaluation of antistatic properties For each example of the examples and comparative examples, when producing a carbon fiber precursor, the electricity generated just before the take-up winder was measured using a digital electrostatic potential meter KSD-1000 (manufactured by Kasuga Electric Co., Ltd.) The measured values ​​were classified into the following three levels. AA: Generated electricity is less than 3kV. A: The generated electricity is between 3kV and 5kV. B: The generated electricity is between 5kV and 7kV. C: The generated electricity is 7kV or more.

[0117] 〔result〕 Tables 2 to 8 show the compositions of the synthetic fiber treating agents of the Examples and Comparative Examples and the evaluation results.

[0118] Table 2: Examples 1 to 15 [Table 2]

[0119] Table 3: Examples 16-30 [Table 3]

[0120] Table 4: Examples 31-41 [Table 4]

[0121] Table 5: Examples 42-52 [Table 5]

[0122] Table 6: Examples 53-62 [Table 6]

[0123] Table 7: Examples 63-68 [Table 7]

[0124] Table 8: Comparative Examples 1 to 7 [Table 8] [Industrial Applicability]

[0125] The present invention can be used, for example, in the production of carbon fiber precursors.

Claims

1. Contains an amino-modified silicone (A) and a glycerin derivative (B), The glycerin derivative (B) is a first ester compound (B1) which is an ester compound of a polyoxyalkylene castor oil ether and at least one compound selected from the group consisting of a carboxylic acid, a hydroxy acid, an alkylene oxide adduct of a hydroxy acid, and a polymer of a hydroxy acid; a second ester compound (B2) which is an ester compound of a polyoxyalkylene hydrogenated castor oil ether and at least one compound selected from the group consisting of a carboxylic acid, a hydroxy acid, an alkylene oxide adduct of a hydroxy acid, and a polymer of a hydroxy acid; and a third ester compound (B3) which is an ester compound of a polyoxyalkylene glyceryl ether and at least one hydroxy acid derivative selected from the group consisting of a carboxylic acid-hydroxy acid ester and a hydroxy acid polymer; At least one ester compound selected from the group consisting of The synthetic fiber treatment agent is characterized in that the carboxylic acid-hydroxy acid ester is an ester compound of a carboxylic acid and at least one compound selected from the group consisting of a hydroxy acid, an alkylene oxide adduct of a hydroxy acid, and a polymer of a hydroxy acid.

2. 2. The synthetic fiber treating agent according to claim 1, wherein the proportion of polyoxyethylene groups in the polyoxyalkylene groups in the glycerin derivative (B) is 99% by mass or more.

3. The glycerin derivative (B) is the first ester compound (B1), the second ester compound (B2), and a specific third ester compound (B3a) which is the third ester compound (B3) having a content of hydroxy acid derivative residues of 2.5 moles or more and 3.0 moles or less per mole of the polyoxyalkylene glyceryl ether residue; 2. The synthetic fiber treating agent according to claim 1, which contains at least one ester compound selected from the group consisting of:

4. the glycerin derivative (B) contains a carboxylic acid residue, 2. The synthetic fiber treating agent according to claim 1, wherein the proportion of residues derived from a monocarboxylic acid among the carboxylic acid residues is 99% by mass or more.

5. relative to the total mass of the amino-modified silicone (A) and the glycerin derivative (B), 2. The synthetic fiber treatment agent according to claim 1, wherein the proportion of the amino-modified silicone (A) is 5% by mass or more and 98% by mass or less.

6. 2. The synthetic fiber treating agent according to claim 1, further comprising at least one cationic compound (C) selected from the group consisting of phosphonium salts and ammonium salts.

7. relative to the total mass of the amino-modified silicone (A), the glycerin derivative (B), and the cationic compound (C), the proportion of the amino-modified silicone (A) is 8.0% by mass or more and 94.5% by mass or less, the proportion of the glycerin derivative (B) is 5.0% by mass or more and 90% by mass or less, 7. The synthetic fiber treating agent according to claim 6, wherein the proportion of the cationic compound (C) is 0.5% by mass or more and 5.0% by mass or less.

8. A synthetic fiber comprising a fiber material to which the synthetic fiber treating agent according to any one of claims 1 to 7 is attached.

9. The synthetic fiber of claim 8, wherein the fiber material is a carbon fiber precursor.

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