Treatment agent for synthetic fiber and synthetic fiber

Abstract

This invention provides a treatment agent for synthetic fibers, characterized by containing an amino-modified silicone (A) and a glycerol derivative (B); the glycerol derivative (B) contains at least one ester compound selected from a first ester compound (B1) as a polyoxyethylene castor oil ether derivative, a second ester compound (B2) as a polyoxyethylene hydrogenated castor oil ether derivative, and a third ester compound (B3) as a polyoxyethylene glycerol ether derivative. This agent can improve the strength and antistatic properties of synthetic fibers.

Description

Technical Field

[0001] This invention relates to a treatment agent for synthetic fibers and synthetic fibers. Background Technology

[0002] A common method for manufacturing carbon fiber involves spinning a fibrous material and then firing it; this fibrous material is referred to as a carbon fiber precursor. Sometimes, carbon fiber precursors are made from fibrous materials such as polymers with a carbon fiber precursor treatment agent attached to their surface. The purpose of using this treatment agent is to improve the operability of the carbon fiber precursor in each step of the carbon fiber manufacturing process. As shown in this example, in the treatment of synthetic fibers, various synthetic fiber treatment agents that can improve the operability of synthetic fibers are sometimes used.

[0003] For example, Japanese Patent No. 7098210 (Patent Document 1) discloses a carbon fiber precursor treatment agent containing a smoothing agent that contains an ester compound as a glycerol derivative. According to the invention described in Patent Document 1, it is possible to reduce the fluffiness of the flame-retardant fibers after flame-retardant treatment of the carbon fiber precursor.

[0004] Existing technical documents

[0005] Patent Document 1: Japanese Patent No. 7098210 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] The invention described in Patent Document 1 has room for improvement in the strength and antistatic properties of synthetic fibers treated with the treatment agent.

[0008] Therefore, it is desirable to develop a synthetic fiber treatment agent that can improve the strength and antistatic properties of synthetic fibers compared with existing technologies, as well as synthetic fibers treated with the synthetic fiber treatment agent.

[0009] Problem-solving methods

[0010] The synthetic fiber treatment agent of the present invention is characterized in that it contains an amino-modified silicone (A) and a glycerol derivative (B); said glycerol derivative (B) contains at least one ester compound selected from a first ester compound (B1), a second ester compound (B2), and a third ester compound (B3); the first ester compound (B1) is an ester compound of polyoxyethylene castor oil ether and at least one compound selected from carboxylic acids, hydroxy acids, alkylene oxide adducts of hydroxy acids, and polymers of hydroxy acids; the second ester compound (B2) is an ester compound of polyoxyethylene hydrogenated castor oil ether and at least one compound selected from carboxylic acids, hydroxy acids, alkylene oxide adducts of hydroxy acids, and polymers of hydroxy acids; said third ester compound (B3) is an ester compound of polyoxyethylene glycerol ether and at least one hydroxy acid derivative selected from carboxylic acid-hydroxy acid esters and polymers of hydroxy acids; said carboxylic acid-hydroxy acid ester is an ester compound of carboxylic acid and at least one compound selected from hydroxy acids, alkylene oxide adducts of hydroxy acids, and polymers of hydroxy acids.

[0011] With this configuration, compared with existing technologies, a synthetic fiber treatment agent that can improve the strength and antistatic properties of synthetic fibers can be obtained.

[0012] As one embodiment, the synthetic fiber treatment agent of the present invention preferably has a polyoxyethylene content of 99% or more in the polyoxyethylene group of the glycerol derivative (B).

[0013] This configuration makes it easier to reduce friction between the synthetic fibers treated with the synthetic fiber treatment agent and the metal, thereby facilitating the smooth winding of the synthetic fibers.

[0014] As one embodiment, the synthetic fiber treatment agent of the present invention preferably contains at least one ester compound selected from the first ester compound (B1), the second ester compound (B2), and a specific third ester compound (B3a); wherein the specific third ester compound (B3a) is a third ester compound (B3) in which the content of hydroxy acid derivative residues of each mole of the polyoxyethylene glycerol ether residue is more than 2.5 moles and less than 3.0 moles.

[0015] This configuration improves the bundle properties of synthetic fibers treated with synthetic fiber treatment agents, thus facilitating the smooth winding of synthetic fibers.

[0016] As one embodiment, the synthetic fiber treatment agent of the present invention preferably contains a glycerol derivative (B) containing carboxylic acid residues, wherein the proportion of residues derived from monocarboxylic acids is 99% or more by mass.

[0017] This configuration makes it difficult for synthetic fibers treated with synthetic fiber treatment agents to fuse together, thus facilitating the unwinding of synthetic fibers wound on rollers and the like.

[0018] As one embodiment, the synthetic fiber treatment agent of the present invention preferably has an amino-modified silicone (A) comprising 5% by mass or more and 98% by mass or less relative to the total mass of the amino-modified silicone (A) and the glycerol derivative (B).

[0019] This composition imparts better strength and antistatic properties to the synthetic fibers treated with the synthetic fiber treatment agent.

[0020] As one embodiment, the synthetic fiber treatment agent of the present invention preferably further contains at least one cationic compound (C) selected from phosphonium salts and ammonium salts.

[0021] This composition imparts better antistatic properties to the synthetic fibers treated with the synthetic fiber treatment agent.

[0022] As one embodiment, the synthetic fiber treatment agent of the present invention preferably comprises, relative to the total mass of the amino-modified silicone (A), the glycerol derivative (B), and the cationic compound (C), the proportion of the amino-modified silicone (A) being 8.0% by mass or more and 94.5% by mass or less, the proportion of the glycerol derivative (B) being 5.0% by mass or more and 90% by mass or less, and the proportion of the cationic compound (C) being 0.5% by mass or more and 5.0% by mass or less.

[0023] This composition imparts better antistatic properties to the synthetic fibers treated with the synthetic fiber treatment agent.

[0024] The synthetic fiber of the present invention is characterized by a treatment agent for attaching the synthetic fiber onto the fiber material.

[0025] This configuration allows for the production of synthetic fibers with improved strength and antistatic properties compared to existing technologies.

[0026] As one embodiment, in the synthetic fiber of the present invention, preferably, the fiber material is a carbon fiber precursor.

[0027] This configuration allows for the production of carbon fiber precursors with improved strength and antistatic properties compared to existing technologies.

[0028] Further features and advantages of the invention will become clearer from the following description of exemplary and non-limiting embodiments. Detailed Implementation

[0029] Embodiments of the synthetic fiber treatment agent and synthetic fibers of the present invention will be described. Hereinafter, examples of applying the synthetic fiber treatment agent of the present invention to the treatment of carbon fiber precursors will be described.

[0030] [Composition of treatment agents for synthetic fibers]

[0031] The synthetic fiber treatment agent of this embodiment contains an amino-modified silicone (A) and a glycerol derivative (B). Furthermore, the synthetic fiber treatment agent of this embodiment preferably also contains a cationic compound (C).

[0032] When the synthetic fiber treatment agent of this embodiment is used as a treatment agent when spinning synthetic fibers, it has been found that the bundle properties of the synthetic fibers are improved, the antistatic properties during winding are improved, and the friction with metal during winding is reduced, thus improving the efficiency of spinning synthetic fibers. Furthermore, when the synthetic fiber treatment agent of this embodiment is used to manufacture carbon fiber precursors, carbon fibers with high strength and difficult to weld can be obtained.

[0033] (Amino-modified silicone)

[0034] Amino-modified silicone (A) is a compound in which an amino group is introduced into the end, side chain, or both of the silicone backbone. When introducing an amino group into the end of the silicone backbone, it can be introduced into two ends or only one end. The introduced amino group is arbitrary and can be a monoamine, diamine, amino polyether, etc. It should be noted that when the end group is not modified, it can be an alkyl group (such as methyl), an alkoxy group (such as methoxy), a hydroxyl group, etc.

[0035] The amino-modified silicone (A) is preferably a kinematic viscosity of 50 mmHg at 25°C. 2 / s or higher and 5000mm 2 Below / s. It should be noted that the kinematic viscosity of amino-modified silicone (A) can be measured using a Cannon-Fenske viscometer.

[0036] Amino-modified silicones can be determined based on the amino equivalent (g / mol) calculated from the total amine value (KOH - mg / g). This total amine value is determined by accurately weighing 1 g of a mixture of 60 mL acetone and 20 mL n-hexane, and then titrating it with a perchloric acid solution of known concentration. The amino equivalent of amino-modified silicones can be above 1000 g / mol and below 15000 g / mol.

[0037] (glycerol derivatives)

[0038] The glycerol derivative (B) contains at least one ester compound selected from the following first ester compound (B1), second ester compound (B2) and third ester compound (B3).

[0039] The first ester compound (B1) is an ester compound of polyoxyethylene castor oil ether and at least one compound selected from carboxylic acids, hydroxy acids, alkyl oxide adducts of hydroxy acids and polymers of hydroxy acids (hereinafter referred to as acid compounds).

[0040] The polyoxyalkylene group in the first ester compound (B1) is not limited and can be polyoxyethylene, polyoxypropylene, etc. Furthermore, the polyoxyalkylene group can be of one type or multiple types. When multiple types of polyoxyalkylene groups are present, they can exist randomly (random adducts) or block-like (block adducts). The polyoxyalkylene group preferably includes polyoxyethylene. It is particularly preferred that the polyoxyethylene content in the polyoxyalkylene group of the first ester compound (B1) is 99% by mass or more, because this can suppress friction between synthetic fibers and metals. It should be noted that in the first ester compound (B1), the polyoxyalkylene group can exist as a polyoxyalkylene castor oil ether residue or as a polyoxyalkylene group in an epoxide adduct residue containing a hydroxy acid.

[0041] There is no particular limitation on the number of polyoxyalkylene groups added to the primary ester compound (B1). For example, each mole of the primary ester compound (B1) can be more than 5 moles and less than 60 moles. It should be noted that when the primary ester compound (B1) contains multiple types of polyoxyalkylene groups, the total number of all polyoxyalkylene groups can be within the above range.

[0042] The acid compound preferably contains a carboxylic acid, and more preferably a monocarboxylic acid. That is, the first ester compound (B1) preferably contains carboxylic acid residues. From the viewpoint of preventing carbon fiber welding, it is particularly preferred that the proportion of residues from monocarboxylic acids in the carboxylic acid residues is 99% by mass or more.

[0043] When the acid compound includes a carboxylic acid, the carboxylic acid can be isostearic acid (monohydric), lauric acid (monohydric), oleic acid (monohydric), 2-ethylhexanoic acid (monohydric), adipic acid (dihydric), maleic acid (dihydric), succinic acid (dihydric), terephthalic acid (dihydric), sebacic acid (dihydric), etc., but is not limited thereto. When the acid compound includes a hydroxy acid, the hydroxy acid can be lactic acid, 3-hydroxyhexanoic acid, 2-hydroxydecanoic acid, 12-hydroxystearic acid, ricinoleic acid, etc., but is not limited thereto. When the acid compound contains an epoxide adduct of a hydroxy acid, it can be an epoxide adduct of the hydroxy acid in the examples above, but is not limited thereto. There is no limitation on the amount of epoxide added in the adduct; for example, each mole of adduct can be more than 5 moles and less than 10 moles. When the acid compound contains a polymer of a hydroxy acid, it can be a polymer of the hydroxy acid in the examples above, but is not limited thereto. There is no particular limitation on the degree of polymerization of the polymer; for example, it can be more than a trimer and less than a hexamer.

[0044] As an example of the first ester compound (B1), an ester compound of polyoxyethylene castor oil ether (an example of polyoxyethylene castor oil ether) and lauric acid (an example of 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.

[0045]

[0046] Formula 1 shows the ester compound resulting from the reaction of polyoxyethylene castor oil ether with lauric acid in a molar ratio of 1:3. That is, in the example of Formula 1, all the hydroxyl groups of the polyoxyethylene castor oil ether are converted to ester bonds. However, in this embodiment, the first ester compound (B1) may also have hydroxyl groups derived from the hydroxyl groups of the polyoxyethylene castor oil ether. That is, the ratio of polyoxyethylene castor oil ether residues to acid compound residues in the first ester compound (B1) is not limited.

[0047] The second ester compound (B2) is an ester compound of polyoxyethylene hydrogenated castor oil ether and at least one compound selected from carboxylic acids, hydroxy acids, alkyl oxide adducts of hydroxy acids and polymers of hydroxy acids (hereinafter referred to as acid compounds).

[0048] The polyoxyalkylene group in the second ester compound (B2) is not limited and can be polyoxyethylene, polyoxypropylene, etc. Furthermore, the polyoxyalkylene group can be of one type or multiple types. When multiple types of polyoxyalkylene groups are present, they can exist randomly (random adducts) or block-like (block adducts). The polyoxyalkylene group preferably includes polyoxyethylene. It is particularly preferred that the polyoxyethylene content in the polyoxyalkylene group of the second ester compound (B2) is 99% by mass or more, because this can suppress friction between synthetic fibers and metals. It should be noted that in the second ester compound (B2), the polyoxyalkylene group can exist as a polyoxyalkylene group in a polyoxyalkylene hydrogenated castor oil ether residue or as a polyoxyalkylene group in an epoxide adduct residue containing a hydroxy acid in an acid compound residue.

[0049] There is no particular limitation on the number of polyoxyalkylene groups added to the second ester compound (B2). For example, each mole of the second ester compound (B2) can contain more than 5 moles and less than 60 moles. It should be noted that when the second ester compound (B2) contains multiple types of polyoxyalkylene groups, the total number of all polyoxyalkylene groups can be within the above range.

[0050] The acid compound preferably contains a carboxylic acid, and more preferably a monocarboxylic acid. That is, the second ester compound (B2) preferably contains carboxylic acid residues. From the viewpoint of preventing carbon fiber welding, it is particularly preferred that the proportion of residues from monocarboxylic acids in the carboxylic acid residues is 99% or more by mass.

[0051] When the acid compound includes a carboxylic acid, the carboxylic acid can be isostearic acid (monocarboxylic), lauric acid (monocarboxylic), oleic acid (monocarboxylic), 2-ethylhexanoic acid (monocarboxylic), adipic acid (dicarboxylic), maleic acid (dicarboxylic), succinic acid (dicarboxylic), terephthalic acid (dicarboxylic), sebacic acid (dicarboxylic), etc., but is not limited thereto. When the acid compound includes a hydroxy acid, the hydroxy acid can be lactic acid, 3-hydroxyhexanoic acid, 2-hydroxydecanoic acid, 12-hydroxystearic acid, ricinoleic acid, etc., but is not limited thereto. When the acid compound contains an epoxide adduct of a hydroxy acid, it can be an epoxide adduct of the hydroxy acid in the examples above, but is not limited thereto. There is no limitation on the amount of epoxide added in the adduct; for example, each mole of adduct can be more than 5 moles and less than 10 moles. When the acid compound contains a polymer of a hydroxy acid, it can be a polymer of the hydroxy acid in the examples above, but is not limited thereto. There is no particular limitation on the degree of polymerization of the polymer; for example, it can be more than a trimer and less than a hexamer.

[0052] As an example of the second ester compound (B2), an ester compound of polyoxyethylene hydrogenated castor oil ether (an example of polyoxyethylene hydrogenated castor oil ether) and oleic acid (an example of 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.

[0053]

[0054] In the second ester compound (B2), there is no limitation on the ratio of polyoxyethylene hydrogenated castor oil ether residues to acid compound residues. Therefore, the second ester compound (B2) can also have hydroxyl groups derived from the hydroxyl groups of polyoxyethylene hydrogenated castor oil ether.

[0055] The third ester compound (B3) is an ester compound of polyoxyethylene glycerol ether and at least one hydroxy acid derivative selected from the polymers of carboxylic acid-hydroxy esters and hydroxy acids. Here, carboxylic acid-hydroxy ester is an ester compound of carboxylic acid and at least one compound selected from the polymers of hydroxy acids, alkylene oxide adducts of hydroxy acids, and polymers of hydroxy acids.

[0056] In the tertiary ester compound (B3), there is no limitation on the ratio of polyoxyethylene glycerol ether residues to hydroxy acid derivative residues. Therefore, the tertiary ester compound (B3) may have hydroxyl groups derived from polyoxyethylene glycerol ether. However, in the tertiary ester compound (B3), it is preferable that the content of hydroxy acid derivative residues per mole of polyoxyethylene glycerol ether residue is 2.5 moles or more and 3.0 moles or less, because at this point, the bundled properties of the synthetic fiber tend to be higher. Hereinafter, the tertiary ester compound (B3) that meets this requirement will be referred to as a specific tertiary ester compound (B3a) for distinction.

[0057] The polyoxyalkylene group in the third ester compound (B3) is not limited and can be polyoxyethylene, polyoxypropylene, etc. Furthermore, the polyoxyalkylene group can be of one type or multiple types. When multiple types of polyoxyalkylene groups are present, they can exist randomly (random adducts) or block-like (block adducts). The polyoxyalkylene group preferably includes polyoxyethylene. It is particularly preferred that the polyoxyethylene content in the polyoxyalkylene group of the third ester compound (B3) is 99% by mass or more, because this can suppress friction between synthetic fibers and metals. It should be noted that in the third ester compound (B3), the polyoxyalkylene group can exist as a polyoxyalkylene glycerol ether residue, or as a polyoxyalkylene group in a residue containing a carboxylic acid-hydroxy ester residue or an epoxide adduct residue of a hydroxy acid.

[0058] There is no particular limitation on the number of polyoxyalkylene groups added to the ter ester compound (B3). For example, each mole of the ter ester compound (B3) can be more than 5 moles and less than 60 moles. It should be noted that when the ter ester compound (B3) contains multiple types of polyoxyalkylene groups, the total number of all polyoxyalkylene groups can be within the above range.

[0059] When the hydroxy acid derivative contains a carboxylic acid-hydroxy ester, it is preferable that the carboxylic acid constituting the carboxylic acid-hydroxy ester contains a monocarboxylic acid. That is, it is preferable that the third ester compound (B3) contains a carboxylic acid-hydroxy ester residue, which contains a carboxylic acid residue. For preventing carbon fiber welding, it is particularly preferable that the proportion of residues from monocarboxylic acids in this carboxylic acid residue is 99% by mass or more. The carboxylic acid constituting the carboxylic acid-hydroxy ester can be isostearic acid (monocarboxylic), lauric acid (monocarboxylic), oleic acid (monocarboxylic), 2-ethylhexanoic acid (monocarboxylic), adipic acid (dicarboxylic), maleic acid (dicarboxylic), succinic acid (dicarboxylic), terephthalic acid (dicarboxylic), sebacic acid (dicarboxylic), etc., but is not limited to these.

[0060] When the compound constituting a carboxylic acid-hydroxy ester contains a hydroxy acid, the hydroxy acid can be lactic acid, 3-hydroxyhexanoic acid, 2-hydroxydecanoic acid, 12-hydroxystearic acid, ricinoleic acid, etc., but is not limited to these. When the compound constituting a carboxylic acid-hydroxy ester contains an epoxide adduct of a hydroxy acid, it can be an epoxide adduct of the hydroxy acid in the examples above, but is not limited to these. There is no limitation on the amount of epoxide added in the adduct; for example, each mole of adduct can be 5 moles or more and 10 moles or less. When the acid compound contains a polymer of a hydroxy acid, it can be a polymer of the hydroxy acid in the examples above, but is not limited to these. There is no particular limitation on the degree of polymerization of the polymer; for example, it can be more than a trimer and less than a hexamer.

[0061] As an example of the third ester compound (B3), an ester compound of polyoxyethylene glycerol ether (an example of polyoxyethylene glycerol ether) and a carboxylic acid-hydroxy ester is shown in Formula 3, wherein the carboxylic acid-hydroxy ester is an ester compound of oleic acid (an example of a carboxylic acid) and 12-hydroxystearic acid (an example of a hydroxy acid). However, the structure of the ester compound of polyoxyethylene glycerol ether and the above-mentioned carboxylic acid-hydroxy ester is not limited to...

[0062] The structure of Equation 3.

[0063]

[0064] (Cat compounds)

[0065] The synthetic fiber treatment agent of this embodiment preferably further contains at least one cationic compound (C) selected from phosphonium salts and ammonium salts. From the viewpoint of preventing synthetic fibers from becoming charged, it is preferable that the synthetic fiber treatment agent contains a cationic compound (C).

[0066] Examples of phosphonium salts include tributylethylphosphonium diethyl phosphate and tetrabutylphosphonium dodecylbenzene sulfonic acid, but are not limited to these.

[0067] Examples of ammonium salts include benzalkonium chloride, benzyl bromide, stearyltrimethylammonium dimethyl phosphate, and dialcyldimethylammonium chloride, but are not limited thereto.

[0068] (Other ingredients)

[0069] The synthetic fiber treatment agent of this embodiment may contain other components besides amino-modified silicone (A), glycerol derivatives (B), and optionally cationic compounds (C). Examples of such other components include, but are not limited to, preservatives, antistatic agents, antioxidants, ultraviolet absorbers, and defoamers.

[0070] The synthetic fiber treatment agent of this embodiment may also contain a silicone compound other than amino-modified silicone (A). Examples of such silicone compounds include dimethyl silicone and polyether-modified silicone, but it is not limited thereto.

[0071] The synthetic fiber treatment agent of this embodiment may contain a polyoxyethylene derivative other than a glycerol derivative (B). This polyoxyethylene derivative may be an epoxide adduct of castor oil, an epoxide adduct of hydrogenated castor oil, an epoxide adduct of saturated or unsaturated alcohols, etc., but is not limited to these.

[0072] (Content of each component)

[0073] In the synthetic fiber treatment agent of this embodiment, preferably, the proportion of amino-modified silicone (A) is 5% by mass or more and 98% by mass or less relative to the total mass of amino-modified silicone (A) and glycerol derivative (B). If the proportion of amino-modified silicone (A) is within the above range, the strength of the obtained carbon fiber is easily increased when the synthetic fiber treatment agent is applied to the manufacture of carbon fiber.

[0074] In the synthetic fiber treatment agent of this embodiment, preferably, relative to the total mass of amino-modified silicone (A), glycerol derivative (B), and cationic compound (C), the proportion of amino-modified silicone (A) is 8.0% by mass or more and 94.5% by mass or less, the proportion of glycerol derivative (B) is 5.0% by mass or more and 90% by mass or less, and the proportion of cationic compound (C) is 0.5% by mass or more and 5.0% by mass or less. If the proportions of amino-modified silicone (A), glycerol derivative (B), and cationic compound (C) are within the above ranges, the strength of the obtained carbon fiber is easily increased when the synthetic fiber treatment agent is applied to the manufacture of carbon fiber.

[0075] [Other implementation methods]

[0076] Regarding other configurations, it should be understood that the embodiments disclosed in this specification are merely illustrative in various respects, and the scope of the invention is not limited thereto. Those skilled in the art will readily understand that appropriate modifications can be made without departing from the spirit of the invention. Therefore, other embodiments obtained by modifications without departing from the spirit of the invention are naturally also included within the scope of the invention.

[0077] Example

[0078] The present invention will be further described below with reference to embodiments. However, the following embodiments do not limit the present invention.

[0079] [Preparation of treatment agents for synthetic fibers]

[0080] The synthetic fiber treatment agents of Examples 1 to 68 and Comparative Examples 1 to 7 shown in Tables 2 to 8 below were obtained using the following methods.

[0081] (1) Reagents

[0082] (1-1) Amino-modified silicone

[0083] As amino-modified silicones, amino-modified silicones A-1 to A-8 having the properties shown in Table 1 were used. All amino-modified silicones conform to the amino-modified silicone (A) described in the above embodiments. It should be noted that the kinematic viscosity and amino equivalent shown in Table 1 are values ​​measured by the methods described in the above embodiments.

[0084] Table 1: Amino-modified silicones

[0085] Table 1

[0086]

[0087] (1-2) Glyceryl derivatives

[0088] (1-2-1) First ester compound

[0089] As glycerol derivatives conforming to the first ester compound, the first ester compounds B1-1 to B1-7 described below were used. All the first ester compounds conform to the first ester compound (B1) of the above embodiments. However, the manufacturing methods shown for each first ester compound are merely examples, and the results of the examples and comparative examples will not change even if the first ester compound is manufactured using a method different from the method described below.

[0090] (First ester compound B1-1)

[0091] Castor oil and ethylene oxide were reacted at a molar ratio of 1:5 to obtain polyoxyethylene castor oil ether. The polyoxyethylene castor oil ether was then reacted with 3-hydroxyhexanoic acid (hydroxy acid) at a molar ratio of 1:1 to obtain the first ester compound B1-1.

[0092] (First ester compound B1-2)

[0093] Castor oil was reacted with ethylene oxide at a molar ratio of 1:10 to obtain polyoxyethylene castor oil ether. Methanesulfonic acid was used as an acid catalyst to react 2-hydroxydecanoic acid with ethylene oxide at a molar ratio of 1:5 to obtain an ethylene oxide adduct of 2-hydroxydecanoic acid. The polyoxyethylene castor oil ether was then reacted with the ethylene oxide adduct of 2-hydroxydecanoic acid at a molar ratio of 1:2 to obtain the first ester compound B1-2.

[0094] (First ester compound B1-3)

[0095] Castor oil is reacted with ethylene oxide at a molar ratio of 1:25 to obtain polyoxyethylene castor oil ether. Polyoxyethylene castor oil ether is then reacted with isostearic acid (a monocarboxylic acid) at a molar ratio of 1:2 to obtain the first ester compound B1-3.

[0096] (First ester compound B1-4)

[0097] Castor oil was reacted with ethylene oxide at a molar ratio of 1:40 to obtain polyoxyethylene castor oil ether. The polyoxyethylene castor oil ether was then reacted with adipic acid (a dicarboxylic acid) at a molar ratio of 1:3 to obtain the first ester compound, B1-4.

[0098] (First ester compound B1-5)

[0099] Castor oil, ethylene oxide, and propylene oxide are reacted in a molar ratio of 1:10:10 to yield polyoxyethylene castor oil ether. The addition of castor oil to ethylene oxide and propylene oxide is a random addition. Using methanesulfonic acid as an acid catalyst, 3-hydroxyhexanoic acid (hydroxy acid), ethylene oxide, and propylene oxide are reacted in a molar ratio of 1:5:5 to yield an alkylene oxide adduct of 3-hydroxyhexanoic acid. The addition of 3-hydroxyhexanoic acid to ethylene oxide and propylene oxide is a random addition. The polyoxyethylene castor oil ether is reacted with the alkylene oxide adduct of 3-hydroxyhexanoic acid in a molar ratio of 1:2 to yield the first ester compound B1-5.

[0100] (First ester compound B1-6)

[0101] Castor oil was reacted with propylene oxide at a molar ratio of 1:10 to obtain polyoxypropylene castor oil ether. The polyoxypropylene castor oil ether was then reacted with lauric acid (a monocarboxylic acid) at a molar ratio of 1:2 to obtain the first ester compound, B1-6.

[0102] (First ester compound B1-7)

[0103] Castor oil, ethylene oxide, and propylene oxide were reacted in a molar ratio of 1:20:40 to obtain polyoxyethylene castor oil ether. Castor oil was then added to ethylene oxide and propylene oxide in a random addition manner. The polyoxyethylene castor oil ether was then reacted with a trimer of lactic acid (hydroxy acid) in a molar ratio of 1:3 to obtain the first ester compound B1-7.

[0104] (1-2-2) Second ester compounds

[0105] The following second ester compounds, B2-1 to B2-6, were used as the second ester compounds. All second ester compounds conform to the second ester compound (B2) in the above embodiments. However, the manufacturing methods shown for each second ester compound are merely examples, and the results of the examples and comparative examples will not change even if the second ester compounds are manufactured using methods different from those in the examples below.

[0106] (Second ester compound B2-1)

[0107] Hydrogenated castor oil is reacted with ethylene oxide at a molar ratio of 1:5 to obtain polyoxyethylene hydrogenated castor oil ether. The polyoxyethylene hydrogenated castor oil ether is then reacted with 12-hydroxystearic acid (hydroxy acid) at a molar ratio of 1:3 to obtain the second ester compound B2-1.

[0108] (Second ester compound B2-2)

[0109] Hydrogenated castor oil is reacted with ethylene oxide at a molar ratio of 1:20 to obtain polyoxyethylene hydrogenated castor oil ether. The polyoxyethylene hydrogenated castor oil ether is then reacted with oleic acid (a monocarboxylic acid) at a molar ratio of 1:2 to obtain a second ester compound, B2-2.

[0110] (Second ester compound B2-3)

[0111] Hydrogenated castor oil was reacted with ethylene oxide at a molar ratio of 1:60 to obtain polyoxyethylene hydrogenated castor oil ether. The polyoxyethylene hydrogenated castor oil ether was then reacted with a hexamer of 12-hydroxystearic acid (hydroxy acid) at a molar ratio of 1:2 to obtain the second ester compound B2-3.

[0112] (Second ester compound B2-4)

[0113] Hydrogenated castor oil was reacted with ethylene oxide at a molar ratio of 1:25 to obtain polyoxyethylene hydrogenated castor oil ether. The polyoxyethylene hydrogenated castor oil ether was then reacted with maleic acid (a dicarboxylic acid) at a molar ratio of 1:1 to obtain the second ester compound B2-4.

[0114] (Second ester compound B2-5)

[0115] Hydrogenated castor oil, ethylene oxide, and propylene oxide were reacted in a molar ratio of 1:10:5 to obtain polyoxyethylene hydrogenated castor oil ether. The addition of hydrogenated castor oil to ethylene oxide and propylene oxide was random. The polyoxyethylene hydrogenated castor oil ether was then reacted with isostearic acid (a monocarboxylic acid) in a molar ratio of 1:1 to give the second ester compound B2-5.

[0116] (Second ester compound B2-6)

[0117] Hydrogenated castor oil was reacted with propylene oxide at a molar ratio of 1:50 to obtain polyoxypropylene hydrogenated castor oil ether. The polyoxypropylene hydrogenated castor oil ether was then reacted with succinic acid (a dicarboxylic acid) at a molar ratio of 1:3 to obtain the second ester compound B2-6.

[0118] (1-2-3) Tertiary ester compounds

[0119] As the third ester compounds, the following third ester compounds B3a-1 to B3a-8 and third ester compounds B3-9 to B3-20 were used. All third ester compounds conform to the third ester compound (B3) in the above embodiments, and third ester compounds B3a-1 to B3a-8 conform to the specific third ester compound (B3a) in the above embodiments. However, the manufacturing methods shown for each third ester compound are merely examples, and the results of the examples and comparative examples will not change even if the third ester compound is manufactured using a method different from the method in the examples below.

[0120] (Tri-ester compound B3a-1)

[0121] Glycerol and ethylene oxide are reacted in a molar ratio of 1:5 to give polyoxyethylene glycerol ether. 2-Ethylhexanoic acid (a monocarboxylic acid) and 3-hydroxyhexanoic acid (a hydroxy acid) are reacted in a molar ratio of 1:1 to give a carboxylic acid-hydroxy ester. Polyoxyethylene glycerol ether is reacted with the carboxylic acid-hydroxy ester in a molar ratio of 1:3 to give the third ester compound B3a-1.

[0122] In the third ester compound B3a-1, the content of 3-hydroxyhexanoic acid residues (hydroxy acid derivative residues) per 1 mole of polyoxyethylene glycerol ether residue is 3 moles, which corresponds to the molar ratio when polyoxyethylene glycerol ether and carboxylic acid-hydroxy ester are reacted. It should be noted that in the examples below, the content of hydroxy acid derivative residues per 1 mole of polyoxyethylene glycerol ether residue in the third ester compound corresponds to the molar ratio when polyoxyethylene glycerol ether and carboxylic acid-hydroxy ester are reacted.

[0123] (Tri-ester compound B3a-2)

[0124] Glycerol is reacted with ethylene oxide at a molar ratio of 1:20 to obtain polyoxyethylene glycerol ether. Oleic acid (a monocarboxylic acid) is reacted with 12-hydroxystearic acid (a hydroxy acid) at a molar ratio of 1:1 to obtain a carboxylic acid-hydroxy ester. The polyoxyethylene glycerol ether is then reacted with the carboxylic acid-hydroxy ester at a molar ratio of 1:3 to obtain the third ester compound B3a-2.

[0125] (Tri-ester compound B3a-3)

[0126] Glycerol is reacted with ethylene oxide at a molar ratio of 1:35 to obtain polyoxyethylene glycerol ether. Using methanesulfonic acid as an acid catalyst, 12-hydroxystearic acid (hydroxy acid) is reacted with ethylene oxide at a molar ratio of 1:5 to obtain an ethylene oxide adduct of 12-hydroxystearic acid. Isostearic acid (a monocarboxylic acid) is reacted with the ethylene oxide adduct of 12-hydroxystearic acid at a molar ratio of 1:1 to obtain a carboxylic acid-hydroxy ester. Polyoxyethylene glycerol ether is reacted with the carboxylic acid-hydroxy ester at a molar ratio of 1:3 to obtain the third ester compound B3a-3.

[0127] (Tri-ester compound B3a-4)

[0128] Glycerol is reacted with ethylene oxide at a molar ratio of 1:50 to obtain polyoxyethylene glycerol ether. The polyoxyethylene glycerol ether is then reacted with a hexamer of 12-hydroxystearic acid (hydroxy acid) at a molar ratio of 1:3 to obtain the third ester compound B3a-4.

[0129] (Tri-ester compound B3a-5)

[0130] Glycerol and ethylene oxide are reacted at a molar ratio of 1:10 to obtain polyoxyethylene glycerol ether. Terephthalic acid (a dicarboxylic acid) and 12-hydroxystearic acid (a hydroxy acid) are reacted at a molar ratio of 1:1 to obtain a carboxylic acid-hydroxy ester. Polyoxyethylene glycerol ether is reacted with the carboxylic acid-hydroxy ester at a molar ratio of 1:3 to obtain the third ester compound B3a-5.

[0131] (Tri-ester compound B3a-6)

[0132] Glycerol is reacted with ethylene oxide at a molar ratio of 1:20 to obtain polyoxyethylene glycerol ether. Sebacic acid (a dicarboxylic acid) is reacted with 12-hydroxystearic acid (a hydroxy acid) at a molar ratio of 1:1 to obtain a carboxylic acid-hydroxy ester. The polyoxyethylene glycerol ether is then reacted with the carboxylic acid-hydroxy ester at a molar ratio of 1:3 to obtain the third ester compound B3a-6.

[0133] (Tri-ester compound B3a-7)

[0134] Glycerol and ethylene oxide are reacted at a molar ratio of 1:25 to obtain polyoxyethylene glycerol ether. Maleic acid (a dicarboxylic acid) and ricinoleic acid (a hydroxy acid) are reacted at a molar ratio of 1:1 to obtain a carboxylic acid-hydroxy ester. The polyoxyethylene glycerol ether is then reacted with the carboxylic acid-hydroxy ester at a molar ratio of 1:3 to obtain the third ester compound B3a-7.

[0135] (Tri-ester compound B3a-8)

[0136] Glycerol is reacted with ethylene oxide at a molar ratio of 1:40 to give polyoxyethylene glycerol ether. Adipic acid (a dicarboxylic acid) is reacted with 3-hydroxyhexanoic acid (a hydroxy acid) at a molar ratio of 1:1 to give a carboxylic acid-hydroxy ester. Polyoxyethylene glycerol ether is reacted with the carboxylic acid-hydroxy ester at a molar ratio of 1:3 to give the third ester compound B3a-8.

[0137] (Tri-ester compound B3-9)

[0138] Glycerol and ethylene oxide are reacted at a molar ratio of 1:15 to obtain polyoxyethylene glycerol ether. Oleic acid (a monocarboxylic acid) is reacted with 12-hydroxystearic acid (a hydroxy acid) at a molar ratio of 1:1 to obtain a carboxylic acid-hydroxy ester. Polyoxyethylene glycerol ether is reacted with the carboxylic acid-hydroxy ester at a molar ratio of 1:2 to obtain the third ester compound B3-9.

[0139] (Tri-ester compound B3-10)

[0140] Glycerol is reacted with ethylene oxide at a molar ratio of 1:45 to give polyoxyethylene glycerol ether. Using methanesulfonic acid as an acid catalyst, 12-hydroxystearic acid (hydroxy acid) is reacted with ethylene oxide at a molar ratio of 1:5 to give an ethylene oxide adduct of 12-hydroxystearic acid. Isostearic acid (a monocarboxylic acid) is reacted with the ethylene oxide adduct of 12-hydroxystearic acid at a molar ratio of 1:1 to give a carboxylic acid-hydroxy ester. Polyoxyethylene glycerol ether is reacted with the carboxylic acid-hydroxy ester at a molar ratio of 1:2 to give the third ester compound B3-10.

[0141] (Tri-ester compound B3-11)

[0142] Glycerol and ethylene oxide were reacted at a molar ratio of 1:5 to obtain polyoxyethylene glycerol ether. The polyoxyethylene glycerol ether was then reacted with a hexamer of 12-hydroxystearic acid (hydroxy acid) at a molar ratio of 1:2 to obtain the third ester compound B3-11.

[0143] (Tri-ester compound B3-12)

[0144] Glycerol is reacted with ethylene oxide at a molar ratio of 1:20 to give polyoxyethylene glycerol ether. Oleic acid (a monocarboxylic acid) is reacted with 12-hydroxystearic acid (a hydroxy acid) at a molar ratio of 1:1 to give a carboxylic acid-hydroxy ester. Polyoxyethylene glycerol ether is reacted with the carboxylic acid-hydroxy ester at a molar ratio of 1:1 to give the third ester compound B3-12.

[0145] (Tri-ester compound B3-13)

[0146] Glycerol and ethylene oxide are reacted at a molar ratio of 1:25 to give polyoxyethylene glycerol ether. Adipic acid (a dicarboxylic acid) and 3-hydroxyhexanoic acid (a hydroxy acid) are reacted at a molar ratio of 1:1 to give a carboxylic acid-hydroxy ester. Polyoxyethylene glycerol ether is reacted with the carboxylic acid-hydroxy ester at a molar ratio of 1:2 to give the third ester compound B3-13.

[0147] (Tri-ester compound B3-14)

[0148] Glycerol and ethylene oxide are reacted at a molar ratio of 1:30 to give polyoxyethylene glycerol ether. Maleic acid (a dicarboxylic acid) and ricinoleic acid (a hydroxy acid) are reacted at a molar ratio of 1:1 to give a carboxylic acid-hydroxy ester. Polyoxyethylene glycerol ether is reacted with the carboxylic acid-hydroxy ester at a molar ratio of 1:2 to give the third ester compound B3-14.

[0149] (Tri-ester compound B3-15)

[0150] Glycerol, ethylene oxide, and propylene oxide are reacted in a molar ratio of 1:10:10 to give polyoxyethylene glycerol ether. The addition of glycerol to ethylene oxide and propylene oxide is random. Oleic acid (a monocarboxylic acid) is reacted with 12-hydroxystearic acid (a hydroxy acid) in a molar ratio of 1:1 to give a carboxylic acid-hydroxy ester. Polyoxyethylene glycerol ether is then reacted with the carboxylic acid-hydroxy ester in a molar ratio of 1:2 to give the third ester compound B3-15.

[0151] (Tri-ester compound B3-16)

[0152] Glycerol, ethylene oxide, and propylene oxide are reacted in a molar ratio of 1:35:5 to give polyoxyethylene glycerol ether. The addition of glycerol to ethylene oxide and propylene oxide is random. 2-Ethylhexanoic acid (a monocarboxylic acid) and 3-hydroxyhexanoic acid (a hydroxy acid) are reacted in a molar ratio of 1:1 to give a carboxylic acid-hydroxy ester. The polyoxyethylene glycerol ether is then reacted with the carboxylic acid-hydroxy ester in a molar ratio of 1:2 to give the third ester compound B3-16.

[0153] (Tri-ester compound B3-17)

[0154] Glycerol, ethylene oxide, and propylene oxide are reacted in a molar ratio of 1:10:20 to yield polyoxyethylene glycerol ether. The addition of glycerol to ethylene oxide and propylene oxide is a block addition reaction, with propylene oxide followed by ethylene oxide in that order. The polyoxyethylene glycerol ether is then reacted with a hexamer of 12-hydroxystearic acid (hydroxy acid) in a molar ratio of 1:1 to yield the third ester compound B3-17.

[0155] (Tri-ester compound B3-18)

[0156] Glycerol, ethylene oxide, and propylene oxide are reacted in a molar ratio of 1:5:35 to give polyoxyethylene glycerol ether. The addition of glycerol to ethylene oxide and propylene oxide is random. Maleic acid (a dicarboxylic acid) and ricinoleic acid (a hydroxy acid) are reacted in a molar ratio of 1:1 to give a carboxylic acid-hydroxy ester. The polyoxyethylene glycerol ether is then reacted with the carboxylic acid-hydroxy ester in a molar ratio of 1:2 to give the third ester compound B3-18.

[0157] (Tri-ester compound B3-19)

[0158] Glycerol and propylene oxide are reacted at a molar ratio of 1:60 to give polyoxypropylene glycerol ether. Adipic acid (a dicarboxylic acid) and 3-hydroxyhexanoic acid (a hydroxy acid) are reacted at a molar ratio of 1:1 to give a carboxylic acid-hydroxy ester. Polyoxypropylene glycerol ether is reacted with the carboxylic acid-hydroxy ester at a molar ratio of 1:2 to give the third ester compound B3-19.

[0159] (Tri-ester compound B3-20)

[0160] Glycerol, ethylene oxide, and propylene oxide are reacted in a molar ratio of 1:20:10 to give polyoxyethylene glycerol ether. The addition of glycerol to ethylene oxide and propylene oxide is a block addition reaction, with ethylene oxide and propylene oxide added sequentially. Adipic acid (a dicarboxylic acid) is reacted with 3-hydroxyhexanoic acid (a hydroxy acid) in a molar ratio of 1:1 to give a carboxylic acid-hydroxy ester. The polyoxyethylene glycerol ether is then reacted with the carboxylic acid-hydroxy ester in a molar ratio of 1:1 to give the third ester compound B3-20.

[0161] (1-3) Cationic compounds

[0162] The following cationic compounds C-1 to C-6 are used as cationic compounds. All cationic compounds conform to the cationic compound (C) of the above embodiments. In addition, cationic compounds C-1 to C-4 are ammonium salts, and cationic compounds C-5 to C-6 are phosphonium salts.

[0163] C-1: Benzalkonium chloride

[0164] C-2: Benzyl bromide

[0165] C-3: Stearyltrimethylammonium dimethyl phosphate

[0166] C-4: Didecyldimethylammonium chloride

[0167] C-5: Tributylethylphosphonium diethyl phosphate

[0168] C-6: Tetrabutylphosphonium dodecylbenzenesulfonic acid

[0169] (1-4) Other components

[0170] Other components are used as follows. Other components Z-1 and Z-2 are silicone compounds. It should be noted that the kinematic viscosity of other components Z-1 and Z-2 is the value measured using a Cannon-Fenske viscometer. Hereinafter, these components will be referred to as silicone compounds Z-1 and Z-2, respectively.

[0171] Z-1: Kinematic viscosity at 25℃ is 350 mmHg. 2 / s of dimethyl silicone

[0172] Z-2: Kinematic viscosity at 25℃ is 1700 mmHg. 2 / s of polyether-modified silicone

[0173] The mass ratio of silicone to polyether is 20:80, and the molar ratio of polyoxyethylene to polyoxypropylene in the polyether portion is 40:60.

[0174] Other components Z-3 to Z-6 are polyoxyethylene derivatives. Hereinafter, these components will be referred to as polyoxyethylene derivatives Z-3 to Z-6, and their manufacturing methods will be described. The manufacturing methods shown here are merely examples; even if the polyoxyethylene derivatives are manufactured using methods different from those described below, the results of the examples and comparative examples will not change.

[0175] Z-3: Polyoxyethylene hydrogenated castor oil ether obtained by reacting hydrogenated castor oil with ethylene oxide at a molar ratio of 1:20.

[0176] Z-4: Polyoxyethylene isononyl ether obtained by reacting isononol with ethylene oxide at a molar ratio of 1:15.

[0177] Z-5: Polyoxyethylene dodecyl ether obtained by reacting secondary dodecyl alcohol with ethylene oxide at a molar ratio of 1:9.

[0178] Z-6: A polyoxyethylene oleyl ether obtained by reacting oleyl alcohol, ethylene oxide, and propylene oxide in a molar ratio of 1:45:5, wherein the addition of oleyl alcohol to ethylene oxide and propylene oxide is a block addition in the order of propylene oxide and ethylene oxide.

[0179] (2) Preparation of treatment agents for synthetic fibers

[0180] (Preparation of Example 1)

[0181] The following components were weighed and placed in beakers: amino-modified silicone A-5 (45% by mass), primary ester compound B1-1 (35% by mass), cationic compound C-6 (1% by mass), and polyoxyethylene derivative Z-5 (19% by mass). After thoroughly mixing all the components, deionized water was slowly added while stirring to prepare an aqueous solution with a total concentration of 30% by mass. This solution was used as the synthetic fiber treatment agent in Example 1.

[0182] (Preparation of other examples and comparative examples)

[0183] Except for changing the type and proportion of the reagents used for mixing, the synthetic fiber treatment agents for each example were prepared using the same method as in Example 1. The preparation conditions for all examples, including Example 1, are shown in Tables 2 to 8 below.

[0184] [Evaluation of Treatment Agents for Synthetic Fibers]

[0185] (1) Production of carbon fiber

[0186] (1-1) Production of fiber materials

[0187] A copolymer with an intrinsic viscosity of 1.80, consisting of 95% by mass acrylonitrile, 3.5% by mass methyl acrylate, and 1.5% by mass methacrylic acid, was dissolved in dimethylacetamide (DMAC) to prepare a spinning solution with a polymer concentration of 21.0% by mass and a viscosity of 500 poise at 60°C. The spinning solution was extruded from a spinneret with an orifice diameter (inner diameter) of 0.075 mm and 12,000 orifices at a draw ratio of 0.8 into a coagulation bath of a 70% by mass aqueous solution of DMAC maintained at a spinning bath temperature of 35°C. The coagulated fibers were desolventized in a washing bath while being stretched five times to obtain a water-swollen acrylic fiber bundle (an example of a fiber material).

[0188] (1-2) Fabrication of carbon fiber precursor

[0189] For the prepared acrylic fiber bundles, the synthetic fibers of the examples and comparative examples were provided with a 4% ion-exchange aqueous solution of the treatment agent by impregnation, with the amount of treatment agent adhering to the bundle being 1% by mass (excluding solvent). Then, the acrylic fiber bundles with the treatment agent adhering to them were dried and densified using heated rollers at 150°C, and then stretched 1.7 times between heated rollers at 170°C before being wound onto a filament tube to obtain a carbon fiber precursor.

[0190] (1-3) Carbon fiber production

[0191] Fibers were unwound from the carbon fiber precursors of the various embodiments and comparative examples, and subjected to flame-retardant treatment in an air atmosphere for 1 hour in a flame-retardant furnace with a temperature gradient of 230–270°C. The resulting filaments were then wound onto a filament tube to obtain flame-retardant filaments. Further, the flame-retardant filaments were unwound and fired in a nitrogen atmosphere in a carbonization furnace with a temperature gradient of 300–1300°C to transform them into carbon fibers, which were then wound onto a filament tube to obtain carbon fibers.

[0192] (2) Evaluation of the strength of carbon fiber

[0193] The tensile strength of the carbon fibers in each example and comparative example was determined according to JIS R 7606:2000. Based on the measured tensile strength values, they were classified into the following three levels.

[0194] A: Tensile strength is above 4.5 GPa.

[0195] B: Tensile strength is above 3.5 GPa and less than 4.5 GPa.

[0196] C: Tensile strength less than 3.5 GPa.

[0197] (3) Evaluation of fiber-metal friction

[0198] For each embodiment and comparative example, during the manufacture of the carbon fiber precursor, the occurrence and frequency of filament breakage in the winding machine were observed. Based on the observation results, they were classified into the following three levels.

[0199] A: No yarn breakage occurred from the start of spinning until 24 hours later.

[0200] B: Fewer than two yarn breaks were observed from the start of spinning until 24 hours later, but this did not affect the operation.

[0201] C: More than 3 yarn breaks were found from the start of spinning to 24 hours, affecting the operation.

[0202] (4) Evaluation of clustering

[0203] For each embodiment and comparative example, the bundled state of the acrylic fiber bundles as they passed through the heated rollers was observed visually. Based on the observation results, they were categorized into the following three levels.

[0204] A: The bundled state is good, and no entanglement with the heating roller was found.

[0205] B: The threads are slightly sparse, but there are no broken threads, so it does not affect the operation.

[0206] C: The filaments were found to be scattered on multiple occasions, resulting in filament breakage and affecting operation.

[0207] (5) Evaluation of anti-welding properties

[0208] For the carbon fibers in each embodiment and comparative example, 1 cm specimens were cut from 10 randomly selected locations to obtain 10 specimens. The welding state of the fibers in each specimen was visually observed, and the number of welding locations was counted. Based on the average number of welding locations in the ten specimens, they were divided into the following three levels.

[0209] A: On average, there are fewer than 2 weld points per specimen.

[0210] B: On average, each specimen has more than 2 but less than 7 weld points.

[0211] C: On average, there are more than 7 weld points per specimen.

[0212] (6) Evaluation of antistatic properties

[0213] For each embodiment and comparative example, during the manufacture of the carbon fiber precursor, the electrical current generated directly in front of the winding machine was measured using a KSD-1000 digital electrostatic potential meter (manufactured by Kasuga Electric Co., Ltd.). The measured values ​​were categorized into the following three levels.

[0214] AA: The generated power is less than 3kV.

[0215] A: The generated power is above 3kV and below 5kV.

[0216] B: The generated power is above 5kV and below 7kV.

[0217] C: The generated power is above 7kV.

[0218] [result]

[0219] The composition and evaluation results of the synthetic fiber treatment agents of each embodiment and comparative example are shown in Tables 2 to 8.

[0220] Table 2: Examples 1-5

[0221] Table 2

[0222]

[0223] Table 3: Examples 16-30

[0224] Table 3

[0225]

[0226] Table 4: Examples 31-41

[0227] Table 4

[0228]

[0229] Table 5: Examples 42-52

[0230] Table 5

[0231]

[0232] Table 6: Examples 53-62

[0233] Table 6

[0234]

[0235] Table 7: Examples 63-68

[0236] Table 7

[0237]

[0238] Table 8: Comparative Examples 1-7

[0239] Table 8

[0240]

[0241] Industrial applicability: This invention can be used, for example, in the manufacture of carbon fiber precursors.

Claims

1. A treatment agent for synthetic fibers, characterized in that, The synthetic fiber treatment agent contains amino-modified silicone (A) and glycerol derivative (B); The glycerol derivative (B) contains at least one ester compound selected from the first ester compound (B1), the second ester compound (B2), and the third ester compound (B3); The first ester compound (B1) is an ester compound of polyoxyethylene castor oil ether and at least one compound selected from carboxylic acids, hydroxy acids, alkylene oxide adducts of hydroxy acids and polymers of hydroxy acids; The second ester compound (B2) is an ester compound of polyoxyethylene hydrogenated castor oil ether and at least one compound selected from carboxylic acids, hydroxy acids, alkylene oxide adducts of hydroxy acids and polymers of hydroxy acids; The third ester compound (B3) is an ester compound of polyoxyethylene glycerol ether and at least one hydroxy acid derivative selected from polymers of carboxylic acid-hydroxy acid esters and hydroxy acids; The carboxylic acid-hydroxy ester is an ester compound of a carboxylic acid and at least one compound selected from hydroxy acids, alkyl oxide adducts of hydroxy acids, and polymers of hydroxy acids.

2. The synthetic fiber treatment agent as described in claim 1, wherein, In the polyoxyethylene group of the glycerol derivative (B), the proportion of polyoxyethylene is more than 99% by mass.

3. The synthetic fiber treatment agent as described in claim 1, wherein, The glycerol derivative (B) contains at least one ester compound selected from the first ester compound (B1), the second ester compound (B2), and a specific third ester compound (B3a); The specific third ester compound (B3a) is a third ester compound (B3) in which the content of hydroxy acid derivative residues of the polyoxyethylene glycerol ether residue is more than 2.5 moles and less than 3.0 moles per mole.

4. The synthetic fiber treatment agent as described in claim 1, wherein, The glycerol derivative (B) contains carboxylic acid residues; The proportion of carboxylic acid residues derived from monocarboxylic acids is 99% or more by mass.

5. The synthetic fiber treatment agent as described in claim 1, wherein, The proportion of amino-modified silicone (A) relative to the total mass of the amino-modified silicone (A) and the glycerol derivative (B) is more than 5% by mass and less than 98% by mass.

6. The synthetic fiber treatment agent as described in claim 1, wherein, The synthetic fiber treatment agent also contains at least one cationic compound (C) selected from phosphonium salts and ammonium salts.

7. The synthetic fiber treatment agent as described in claim 6, wherein, Relative to the total mass of the amino-modified silicone (A), the glycerol derivative (B), and the cationic compound (C); The proportion of the amino-modified silicone (A) is more than 8.0% by mass and less than 94.5% by mass; The proportion of the glycerol derivative (B) is more than 5.0% by mass and less than 90% by mass; The proportion of the cationic compound (C) is more than 0.5% by mass and less than 5.0% by mass.

8. A synthetic fiber, characterized in that, Treatment agent for attaching synthetic fibers according to any one of claims 1 to 7 onto fibrous materials.

9. The synthetic fiber as described in claim 8, wherein, The fiber material is a carbon fiber precursor.

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