Treatment agent for carbon fiber precursor and carbon fiber precursor

Abstract

The treatment agent for carbon fiber precursor according to the present application is characterized by containing a saturated monoalcohol (A), a nonionic surfactant (B), and a smoothing agent (C) that contains a silicone (C1). The treatment agent for carbon fiber precursor can prevent the attachment of scum to a roll, improve the bundling property of the carbon fiber precursor, and improve emulsion stability.

Description

TECHNICAL FIELD

[0001] The present application relates to a treatment agent for a carbon fiber precursor and a carbon fiber precursor. BACKGROUND

[0002] As a method for producing carbon fibers, a method of spinning a fiber-like material and then firing the material is generally employed, and the fiber-like material is referred to as a carbon fiber precursor. As the carbon fiber precursor, a carbon fiber precursor having a treatment agent for a carbon fiber precursor attached to the surface of a fiber material such as a polymer is sometimes used. The treatment agent is used for the purpose of improving the handleability of the carbon fiber precursor in each step when producing carbon fibers and the like.

[0003] In International Publication No. 2018 / 163739 (Patent Document 1), a treatment agent for acrylic fibers containing an amino-modified silicone, a Bronsted acid compound, and an acetylene-based surfactant is disclosed. The acrylic fibers for carbon fiber production manufactured by imparting the treatment agent described in Patent Document 1 are not easily deteriorated even in the case of long-term storage.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT DOCUMENTS

[0006] Patent Document 1: International Publication No. 2018 / 163739 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] The carbon fiber precursor is generally wound on a winding device such as a winder after continuously passing through steps of spinning, stretching, drying, and imparting a treatment agent and the like. In this continuous step, the carbon fiber precursor passes through each step while being guided by a guide member such as a roll. In terms of preventing dross from adhering to the roll and improving the bundling property of the wound carbon fiber precursor, there is room for improvement in the carbon fiber precursor to which the treatment agent described in Patent Document 1 is imparted. In addition, the mechanical stability of the dispersion (emulsion) of the treatment agent described in Patent Document 1 is low, and problems such as the generation of a gel in an oil bath sometimes occur. Therefore, there are cases where the continuous production of the carbon fiber precursor is hindered.

[0009] Therefore, a treatment agent for a carbon fiber precursor capable of preventing dross from adhering to a roll, improving the bundling property of a carbon fiber precursor, and improving the stability of an emulsion, and a carbon fiber precursor to which the treatment agent is imparted are required to be achieved.

[0010] MEANS FOR SOLVING THE PROBLEMS

[0011] The treatment agent for a carbon fiber precursor of the present application is characterized by containing a saturated monoalcohol (A), a nonionic surfactant (B), and a smoothing agent (C), and the smoothing agent (C) contains a silicone (C1).

[0012] The carbon fiber precursor of the present application is characterized in that a treatment agent for carbon fiber precursor is attached.

[0013] According to these structures, it is possible to prevent the attachment of dross to the roll, improve the coalescence of the carbon fiber precursor, and improve the stability of the emulsion. Furthermore, it is possible to obtain a carbon fiber precursor having excellent friction properties.

[0014] Hereinafter, preferred modes of the present application will be described. However, the scope of the present application is not limited by the examples of the preferred modes described below.

[0015] The treatment agent for carbon fiber precursor of the present application, as one mode, preferably, the number of carbon atoms of the above-mentioned saturated monoalcohol (A) is 8 or more and 26 or less.

[0016] According to this structure, dross is particularly less likely to be generated.

[0017] The treatment agent for carbon fiber precursor of the present application, as one mode, preferably, the above-mentioned saturated monoalcohol (A) has a branched chain at the β position of the hydroxyl group.

[0018] According to this structure, the stability of the emulsion of the treatment agent for carbon fiber precursor is further improved.

[0019] The treatment agent for carbon fiber precursor of the present application, as one mode, preferably, the proportion of the above-mentioned saturated monoalcohol (A) in the non-volatile components is 0.1 mass% or more and 20 mass% or less.

[0020] According to this structure, the coalescence of the carbon fiber precursor is further improved.

[0021] The treatment agent for carbon fiber precursor of the present application, as one mode, preferably, the above-mentioned silicone (C1) contains an amino-modified silicone.

[0022] According to this structure, the friction properties of the carbon fiber precursor to which the treatment agent for carbon fiber precursor is imparted are further improved.

[0023] The treatment agent for carbon fiber precursor of the present application, as one mode, preferably, the above-mentioned nonionic surfactant (B) contains an alkylene oxide adduct (B1) of a monoalcohol having a branched chain at the β position of the hydroxyl group.

[0024] According to this structure, the stability of the emulsion of the treatment agent for carbon fiber precursor is further improved.

[0025] The carbon fiber precursor treatment agent of the present application, as one mode, preferably has, in the nonvolatile components, the above-mentioned saturated monoalcohol (A) in a proportion of 0.1 mass% or more and 20 mass% or less, the above-mentioned nonionic surfactant (B) in a proportion of 10 mass% or more and 70 mass% or less, and the above-mentioned smoothing agent (C) in a proportion of 29.9 mass% or more and 89.9 mass% or less.

[0026] According to this structure, it is possible to achieve, at a high level, prevention of dross attachment on the roll, improvement of the cohesiveness of the carbon fiber precursor, and improvement of emulsion stability.

[0027] Further features and advantages of the present application will become more apparent from the following description of exemplary and non-limiting embodiments. DETAILED DESCRIPTION

[0028] Embodiments of the carbon fiber precursor treatment agent and the carbon fiber precursor of the present application will be described. Hereinafter, an example in which the carbon fiber precursor treatment agent of the present application (hereinafter sometimes referred to simply as "treatment agent") is applied to the treatment of a carbon fiber precursor will be described.

[0029] [Structure of the carbon fiber precursor treatment agent]

[0030] The carbon fiber precursor treatment agent of the present embodiment contains a saturated monoalcohol (A), a nonionic surfactant (B), and a smoothing agent (C) as nonvolatile components. Note that the nonvolatile components of the treatment agent refer to components that do not volatilize and remain when the treatment agent is heated for 2 hours at 105°C using a hot air drier.

[0031] (Saturated monoalcohol)

[0032] The saturated monoalcohol (A) is a saturated monoalcohol compound as the name implies. That is, the saturated monoalcohol (A) is a compound in which one hydrogen atom of a saturated hydrocarbon is substituted with a hydroxyl group. Note that the saturated monoalcohol (A) can be one saturated monoalcohol compound or a mixture of a plurality of saturated monoalcohol compounds.

[0033] The saturated monoalcohol (A) preferably has a carbon atom number of 8 or more and 26 or less. The saturated monoalcohol (A) is preferably 8 or more in terms of the fact that it is less likely to cause roller sucm in the spinning step of spinning the carbon fiber precursor. It is also preferable for the saturated monoalcohol (A) to be 26 or less because it is less likely to cause roller sucm. The saturated monoalcohol (A) is more preferably 12 or more. The saturated monoalcohol (A) is more preferably 24 or less. When the saturated monoalcohol (A) is a mixture of a plurality of saturated monoalcohol compounds, it is preferable for at least one of the saturated monoalcohol compounds that make up the mixture to have a carbon atom number within the above-mentioned range, and more preferably all of the saturated monoalcohol compounds have a carbon atom number within the above-mentioned range.

[0034] Preferably, the saturated monoalcohol (A) has a branched chain at the β position of the hydroxyl group. That is, the saturated monoalcohol (A) of the preferred embodiment is represented by the following general formula (1).

[0035]

[0036] In general formula (1), R 1 and R 2 are saturated alkyl groups. In the preferred embodiment, the total (n + m) of the number of carbon atoms n of R 1 and the number of carbon atoms m of R 2 is 6 or more and 24 or less. R 1 and R 2 are preferably at least one saturated chain alkyl group, and more preferably both are saturated chain alkyl groups. When the saturated monoalcohol (A) is a mixture of a plurality of saturated monoalcohol compounds, it is preferable that at least one of the saturated monoalcohol compounds constituting the mixture be represented by general formula (1), and more preferably the number of carbon atoms of all of the saturated monoalcohol compounds be represented by general formula (1).

[0037] As non-limiting examples of the saturated monoalcohol (A), 2-(1,3,3-trimethylbutyl)-5,7,7-trimethyl-1-octanol (carbon atom number 18, n = 9, m = 7), 2-(4-methylhexyl)-8-methyl-1-decanol (carbon atom number 18, n = 9, m = 7), 2-hexyl-1-decanol (carbon atom number 16, n = 8, m = 6), 2-octyl-1-decanol (carbon atom number 18, n = 8, m = 8), 2-hexyl-1-dodecanol (carbon atom number 18, n = 10, m = 6), 2-octyl-1-dodecanol (carbon atom number 20, n = 10, m = 8), 2-ethyl-1-hexanol (carbon atom number 8, n = 4, m = 2), 2-butyl-1-octanol (carbon atom number 12, n = 6, m = 4), 2-decyl-1-tetradecanol (carbon atom number 24, n = 12, m = 10), 2-(4-methylnonyl)-7-methyl-1-tetradecanol (carbon atom number 25, n = 13, m = 10), 2-dodecyl-1-hexadecanol (carbon atom number 28, n = 14, m = 12), 2-tetradecyl-1-octadecanol (carbon atom number 32, n = 16, m = 14), 16-methyl-1-heptadecanol (carbon atom number 18), 1-dodecanol (carbon atom number 12), 1-nonanol (carbon atom number 9), 3,5,5-trimethyl-1-hexanol (carbon atom number 9), 1-octadecanol (carbon atom number 18), 1-hexanol (carbon atom number 6), and cyclohexanol (carbon atom number 6) can be mentioned. Note that the compounds in which the values of n and m are described in the above exemplified saturated monoalcohol compounds are examples of the saturated monoalcohol (A) represented by General Formula (1). Note that a mixture of a plurality of saturated monoalcohol compounds selected from the above exemplified compound group is also an example of the saturated monoalcohol (A).

[0038] The treatment agent of the present embodiment preferably has a proportion of the saturated monoalcohol (A) in the non-volatile component of 0.1 mass% or more and 20 mass% or less. When the proportion of the saturated monoalcohol (A) is 0.1 mass% or more, this is preferable in terms of not easily causing roll dross. When the proportion of the saturated monoalcohol (A) is 20 mass% or less, the bundle property of the carbon fiber precursor easily becomes high. More preferably, the proportion of the saturated monoalcohol (A) in the non-volatile component is 1 mass% or more and 20 mass% or less, and further preferably, 1 mass% or more and 18 mass% or less.

[0039] (nonionic surfactant)

[0040] The nonionic surfactant (B) can be any nonionic surfactant commonly used in the art. The nonionic surfactant (B) can be one compound or a mixture of a plurality of compounds.

[0041] The nonionic surfactant (B) can be, for example, an alkylene oxide adduct of a compound having a hydroxyl group or a derivative (e.g., esterified product, etc.) thereof. Preferably, the nonionic surfactant (B) includes an alkylene oxide adduct of a monoalcohol having a branched chain at the β position of the hydroxyl group (B1) (hereinafter sometimes referred to as nonionic surfactant (B1)).

[0042] The nonionic surfactant (B1) of the preferred mode is represented by the following general formula (2).

[0043]

[0044] In general formula (2), R 3 and R 4 are any hydrocarbon group, and R 5 is an alkylene oxide residue. R 3 and R 4 are preferably at least one saturated alkyl group, and more preferably both are saturated alkyl groups. Further, R 3 and R 4 are preferably at least one chain alkyl group, and more preferably both are chain alkyl groups. Thus, particularly preferably, R 3 and R 4 are both saturated chain alkyl groups.

[0045] Preferably, R 5 includes one or both of an ethylene oxide residue (-(C2H4O)x-) and a propylene oxide residue (-(C3H6)x-).

[0046] When the nonionic surfactant (B) is a mixture of a plurality of nonionic surfactants, preferably, at least one of the nonionic surfactants constituting the mixture is the nonionic surfactant (B1) (general formula (2)), and more preferably, all of the nonionic surfactants are the nonionic surfactant (B1) (general formula (2)).

[0047] In the case where the nonionic surfactant (B) is an alkylene oxide adduct of a compound having a hydroxyl group, non-limiting examples are shown. The compounds listed as non-limiting examples of the above-mentioned saturated monoalcohols (A) are all examples of compounds that provide a hydroxyl group to the nonionic surfactant (B). That is, as the compound having a hydroxyl group, 2-(1,3,3-trimethylbutyl)-5,7,7-trimethyl-1-octanol, 2-(4-methylhexyl)-8-methyl-1-decanol, 2-hexyl-1-decanol, 2-octyl-1-decanol, 2-hexyl-1-dodecanol, 2-octyl-1-dodecanol, 2-ethyl-1-hexanol, 2-butyl-1-octanol, 2-dodecyl-1-tetradecanol, 2-(4-methylnonyl)-7-methyl-1-tetradecanol, 2-dodecyl-1-hexadecanol, 2-tetradecyl-1-octadecanol, 16-methyl-1-heptadecanol, 1-dodecanol, 1-nonanol, 3,5,5-trimethyl-1-hexanol, 1-octadecanol, 1-hexanol, and cyclohexanol can be exemplified. In addition, as other examples of the compound having a hydroxyl group, 11-methyl-undecanol, tetradecanol, tridecanol, dodecanol, sec-tetradecanol, sec-tridecanol, tristyryl phenol, distyryl phenol, and bisphenol A can be exemplified. As non-limiting examples of the alkylene oxide, ethylene oxide and propylene oxide can be exemplified.

[0048] Accordingly, the nonionic surfactant (B) can be, for example, a compound obtained by reacting one or more of the above-mentioned exemplified compounds having a hydroxyl group with one or more of the above-mentioned exemplified alkylene oxides in a prescribed molar ratio. In terms of the nature of the addition reaction of the alkylene oxide, the product of the above-mentioned reaction is usually a mixture of a plurality of compounds differing in the number of alkylene oxide additions. Accordingly, the nonionic surfactant (B) can be determined depending on the kind of the compound having a hydroxyl group and the alkylene oxide used as the substrate, and the molar ratio thereof.

[0049] The nonionic surfactant (B) can be an alkylene oxide adduct of an amine compound or a derivative thereof (e.g., esterification product, etc.). As a non-limiting example in this case, an ethylene oxide adduct of dodecylamine can be exemplified.

[0050] The treatment agent of the present embodiment preferably has a proportion of the nonionic surfactant (B) in the nonvolatile component of 10% by mass or greater and 70% by mass or less. When the proportion of the nonionic surfactant (B) is 10% by mass or greater and 70% by mass or less, this is preferable in terms of emulsification becoming easier. More preferably, the proportion of the nonionic surfactant (B) in the nonvolatile component is 15% by mass or greater and 70% by mass or less, and further preferably 20% by mass or greater and 70% by mass or less. Note that when the nonionic surfactant (B) is a mixture of a plurality of nonionic surfactants, the proportion of the nonionic surfactant (B) in the nonvolatile component indicates the total of the proportions of the plurality of nonionic surfactants.

[0051] (Smoothing agent)

[0052] The smoothing agent (C) contains a silicone (C1). The smoothing agent (C) can be one compound or a mixture of a plurality of compounds. When the smoothing agent (C) includes a plurality of compounds, it can be a mixture of a plurality of silicones (C1) or a mixture of one or more silicones (C1) and one or more non-silicone smoothing agents (C2). The smoothing agent (C) preferably contains 15% by mass or greater of a silicone (C1).

[0053] The silicone (C1) can be determined according to the kinematic viscosity at 25°C measured by a Cannon-Fenske viscometer. The kinematic viscosity of the silicone at 25°C can be 80 mm 2 / s or greater and 2000 mm 2 / s or less.

[0054] The silicone (C1) preferably contains an amino-modified silicone. The manner in which the amino-modified silicone is modified is arbitrary. Thus, the amino-modified silicone can be a compound in which an amino group is introduced into the terminal end, side chain, or both of a silicone main chain. In the case where an amino group is introduced into the terminal end of the silicone main chain, the amino group can be introduced into both terminal ends or only one terminal end. Furthermore, the introduced amino group is arbitrary and can be a monoamine, diamine, amino polyether, or the like. In the case where the terminal group is not modified, the terminal group can be a hydroxyl group, methoxyl group, or the like.

[0055] The amino-modified silicone can be determined according to the amino equivalent (g / mol) calculated from the total amine value (KOH-mg / g). The total amine value is determined by titration with a perchloric acid solution of known concentration after accurately weighing 1 g of a mixture of 60 mL of acetone and 20 mL of n-hexane. The amino equivalent of the amino-modified silicone can be 2000 or greater and 8000 or less.

[0056] The silicone (C1) can be a modified silicone other than an amino-modified silicone. As the modified silicone, a polyether-modified silicone, a carboxyl-modified silicone, a hydroxyl-modified silicone, an alkyl-modified silicone, and the like can be exemplified.

[0057] The non-silicone smoothing agent (C2) can be any non-silicone smoothing agent commonly used in the technical field. As non-limiting examples of the non-silicone smoothing agent (C2), a reaction product of polybutenyl succinic anhydride and triethylenetetramine, a reaction product of polybutenyl-modified phenol, formaldehyde, and triethylenetetramine, and mineral oil can be exemplified.

[0058] The treatment agent of the present embodiment preferably has a proportion of the smoothing agent (C) in the non-volatile component of 29.9 mass% or more and 89.9 mass% or less. When the proportion of the smoothing agent (C) is 29.9 mass% or more, it is preferable in terms of frictional properties. When the proportion of the smoothing agent (C) is 89.9 mass% or less, it is preferable in terms of emulsifiability. More preferably, the proportion of the smoothing agent (C) in the non-volatile component is 29.9 mass% or more and 80 mass% or less, and further preferably 29.9 mass% or more and 75 mass% or less. In addition, when the smoothing agent (C) includes a plurality of compounds, the proportion of the smoothing agent (C) in the non-volatile component indicates the total of the proportions of the plurality of compounds.

[0059] (Other components)

[0060] The treatment agent of the present embodiment can also contain other components in addition to the saturated monoalcohol (A), the nonionic surfactant (B), and the smoothing agent (C). As the other components, a preservative, an antistatic agent, an antioxidant, an ultraviolet absorber, a defoaming agent, and the like can be exemplified, but are not limited to these.

[0061] In addition, as a typical manner of treatment in which the treatment agent is provided to the carbon fiber precursor, a manner in which a diluent is used to dilute the non-volatile component such as the saturated monoalcohol (A) can be exemplified. The diluent is also an example of the other components. As the diluent, water (tap water, industrial water, ion-exchanged water, distilled water, and the like), acetone, methyl ethyl ketone, N-methyl-2-pyrrolidone, and the like can be exemplified, but are not limited to these. In addition, the concentration of the non-volatile component in the treatment agent in the manner in which the diluent is used to dilute the non-volatile component is not particularly limited, and can be, for example, 10 mass% or more and 60 mass% or less. As described above, the non-volatile component of the treatment agent refers to a component that does not volatilize and remains after the treatment agent is heated for 2 hours at 105°C with a hot air dryer, and the concentration refers to the proportion of the mass of the non-volatile component in the treatment agent with respect to the mass of the treatment agent.

[0062] [Method for producing treatment agent for carbon fiber precursor]

[0063] The treatment agent of the present embodiment can be obtained by mixing the saturated monoalcohol (A), the nonionic surfactant (B), the smoothing agent (C), and the optional added components, in a known manner. For example, it can be manufactured by stirring the saturated monoalcohol (A), the nonionic surfactant (B), and the smoothing agent (C), and the optional added components, while adding water at 20°C to 90°C for 5 hours.

[0064] [Carbon fiber precursor]

[0065] The carbon fiber precursor of the present embodiment is in a manner that the treatment agent of the present embodiment is attached to a fiber material that is commonly used as a carbon fiber precursor. The fiber material referred to here means a fiber-like material that becomes a carbon fiber through a firing step, and can be a polyacrylonitrile-based fiber, a polyamide-based fiber, a polyester-based fiber, a polyolefin-based fiber, a cellulose-based fiber, a lignin-based fiber, a phenol resin, pitch, or the like, or a combination thereof.

[0066] As the method of attaching the treatment agent to the fiber material, a method commonly used in the art when attaching such a treatment agent to a fiber material can be applied. That is, an impregnation oil supply method, a spray oil supply method, a roll oil supply method, a guide oil supply method, or the like can be employed. In addition, when each method is applied, the treatment agent can be appropriately diluted with a solvent such as water.

[0067] In the carbon fiber precursor of the present embodiment, the amount of the treatment agent attached is not particularly limited. For example, it is preferable that the treatment agent be attached in an amount of 0.3 mass% or more and 3 mass% or less, relative to the entire carbon fiber precursor to which the treatment agent is attached.

[0068] [Other embodiments]

[0069] For other structures, it should also be understood that the embodiments disclosed herein are exemplary in all respects and the scope of the present application is not limited thereto. Those skilled in the art can easily understand that appropriate changes can be made within the scope of the gist of the present application. Therefore, other embodiments changed within the scope of the gist of the present application are of course included in the scope of the present application.

[0070] [Examples]

[0071] Hereinafter, the present application will be further explained by showing examples. Note that the following examples do not limit the present application.

[0072] [Preparation of treatment agent for carbon fiber precursor]

[0073] The treatment agent for carbon fiber precursor of Examples 1 to 24 and Comparative Examples 1 to 4 shown in Tables 1 to 3 below was obtained by the following method.

[0074] (1) Reagent (1-1) Alcohol

[0075] As the alcohol, the following alcohols A-1 to A-18 and a-1 to a-3 were used. Among them, alcohols A-1 to A-18 are saturated monoalcohols. In addition, alcohols A-1 to A-11 are saturated monoalcohols represented by General Formula (1). The meanings of the number of carbon atoms and n and m described for each alcohol are the same as described in the above embodiment.

[0076] A-1: 2-(1,3,3-trimethylbutyl)-5,7,7-trimethyl-1-octanol (number of carbon atoms: 18, n = 9, m = 7)

[0077] A-2: 2-(4-methylhexyl)-8-methyl-1-decanol (number of carbon atoms: 18, n = 9, m = 7)

[0078] A-3: 2-hexyl-1-decanol (number of carbon atoms: 16, n = 8, m = 6)

[0079] A-4: a mixture of 2-octyl-1-decanol (number of carbon atoms: 18, n = 8, m = 8) and 2-hexyl-1-dodecanol (number of carbon atoms: 18, n = 10, m = 6) at a molar ratio of 50:50

[0080] A-5: 2-octyl-1-dodecanol (number of carbon atoms: 20, n = 10, m = 8)

[0081] A-6: 2-ethyl-1-hexanol (number of carbon atoms: 8, n = 4, m = 2)

[0082] A-7: 2-butyl-1-octanol (number of carbon atoms: 12, n = 6, m = 4)

[0083] A-8: 2-decyl-1-tetradecanol (number of carbon atoms: 24, n = 12, m = 10)

[0084] A-9: 2-(4-methylnonyl)-7-methyl-1-tetradecanol (number of carbon atoms: 25, n = 13, m = 10)

[0085] A-10: 2-dodecyl-1-hexadecanol (number of carbon atoms: 28, n = 14, m = 12)

[0086] A-11: 2-tetradecyl-1-octadecanol (number of carbon atoms: 32, n = 16, m = 14)

[0087] A-12: 16-methyl-1-heptadecanol (number of carbon atoms: 18)

[0088] A-13: 1-dodecanol (number of carbon atoms: 12)

[0089] A-14: 1-nonanol (number of carbon atoms: 9)

[0090] A-15: 3,5,5-trimethyl-1-hexanol (carbon number 9)

[0091] A-16: 1-octadecanol (carbon number 18)

[0092] A-17: 1-hexanol (carbon number 6)

[0093] A-18: cyclohexanol (carbon number 6)

[0094] a-1: 3,6-dimethyl-4-octyn-3,6-diol

[0095] a-2: cis-9-octadecen-1-ol

[0096] a-3: 9Z,12Z-octadecadien-1-ol

[0097] (1-2) Nonionic surfactant

[0098] As the nonionic surfactant, the following nonionic surfactants B-1 to B-17 were used. Any one of the nonionic surfactants conforms to the nonionic surfactant (B) of the above-described embodiment, and the nonionic surfactants B-1 to B-3 conform to the nonionic surfactant (Bl) represented by the general formula (2). However, the manufacturing method shown for each nonionic surfactant is one example, and the results of the examples and comparative examples do not change even in the case where the nonionic surfactant is manufactured in a method different from the method exemplified below.

[0099] (Nonionic surfactant B-1)

[0100] 2-Hexyl-1-decanol and ethylene oxide were reacted at a molar ratio of 1:3 to obtain an ethylene oxide adduct of 2-hexyl-1-decanol, that is, the nonionic surfactant B-1.

[0101] (Nonionic surfactant B-2)

[0102] 2-Hexyl-1-decanol and ethylene oxide were reacted at a molar ratio of 1:6 to obtain an ethylene oxide adduct of 2-hexyl-1-decanol, that is, the nonionic surfactant B-2.

[0103] (Nonionic surfactant B-3)

[0104] 2-Hexyl-1-decanol and ethylene oxide were reacted at a molar ratio of 1:9 to obtain an ethylene oxide adduct of 2-hexyl-1-decanol, that is, the nonionic surfactant B-3.

[0105] (Nonionic surfactant B-4)

[0106] The dodecanol and ethylene oxide were reacted at a molar ratio of 1:9 to obtain an ethylene oxide adduct of dodecanol, that is, a nonionic surfactant B-4.

[0107] (nonionic surfactant B-5)

[0108] The 11-methyl-undecanol and ethylene oxide were reacted at a molar ratio of 1:12 to obtain an ethylene oxide adduct of 11-methyl-undecanol, that is, a nonionic surfactant B-5.

[0109] (nonionic surfactant B-6)

[0110] The tetradecanol and ethylene oxide were reacted at a molar ratio of 1:7 to obtain an ethylene oxide adduct of tetradecanol, that is, a nonionic surfactant B-6.

[0111] (nonionic surfactant B-7)

[0112] The tridecanol and ethylene oxide were reacted at a molar ratio of 1:15 to obtain an ethylene oxide adduct of tridecanol, that is, a nonionic surfactant B-7.

[0113] (nonionic surfactant B-8)

[0114] The dodecanol and ethylene oxide were reacted at a molar ratio of 1:20 to obtain an ethylene oxide adduct of dodecanol, that is, a nonionic surfactant B-8.

[0115] (nonionic surfactant B-9)

[0116] The sec-tetradecanol and ethylene oxide were reacted at a molar ratio of 1:10 to obtain an ethylene oxide adduct of sec-tetradecanol, that is, a nonionic surfactant B-9.

[0117] (nonionic surfactant B-10)

[0118] The sec-tridecanol and ethylene oxide were reacted at a molar ratio of 1:9 to obtain an ethylene oxide adduct of sec-tridecanol, that is, a nonionic surfactant B-10.

[0119] (nonionic surfactant B-11)

[0120] The dodecanol, ethylene oxide and propylene oxide were reacted at a molar ratio of 1:2:6 to obtain a random adduct of ethylene oxide, propylene oxide of dodecanol, that is, a nonionic surfactant B-11.

[0121] (nonionic surfactant B-12)

[0122] The tristyrylphenol, ethylene oxide and propylene oxide were reacted at a molar ratio of 1:15:9 to obtain a tristyrylphenol ethylene oxide, propylene oxide random adduct, i.e., a nonionic surfactant B-12.

[0123] (nonionic surfactant B-13)

[0124] The tristyrylphenol, ethylene oxide and propylene oxide were reacted at a molar ratio of 1:15:9 to obtain a tristyrylphenol ethylene oxide, propylene oxide random adduct, i.e., a nonionic surfactant B-12.

[0125] (nonionic surfactant B-14)

[0126] The tristyrylphenol, ethylene oxide and propylene oxide were reacted at a molar ratio of 1:15:9 to obtain a tristyrylphenol ethylene oxide, propylene oxide random adduct, i.e., a nonionic surfactant B-12.

[0127] (nonionic surfactant B-15)

[0128] The tristyrylphenol, ethylene oxide and propylene oxide were reacted at a molar ratio of 1:15:9 to obtain a tristyrylphenol ethylene oxide, propylene oxide random adduct, i.e., a nonionic surfactant B-12.

[0129] (nonionic surfactant B-16)

[0130] The tristyrylphenol, ethylene oxide and propylene oxide were reacted at a molar ratio of 1:15:9 to obtain a tristyrylphenol ethylene oxide, propylene oxide random adduct, i.e., a nonionic surfactant B-12.

[0131] (nonionic surfactant B-17)

[0132] The tristyrylphenol, ethylene oxide and propylene oxide were reacted at a molar ratio of 1:15:9 to obtain a tristyrylphenol ethylene oxide, propylene oxide random adduct, i.e., a nonionic surfactant B-12.

[0133] (1-3) Smoothing agent

[0134] As the smoothing agent, the following silicone Cl-1 to Cl-11 and non-silicone smoothing agent C2-1 to C2-5 were used. Among them, silicone Cl-1 to Cl-7 is an amino-modified silicone.

[0135] (silicone Cl-1)

[0136] A two-end blocked amino-modified silicone having a kinematic viscosity of 80 mm 2 / s at 25°C, an amino equivalent of 4400, and an amino group of a side chain diamino type was used.

[0137] (silicone Cl-2)

[0138] A two-end blocked amino-modified silicone having a kinematic viscosity of 80 mm2 / s, amino equivalent of 3000, amino group is a side chain monoamino type, and is a two-end blocked amino-modified silicone.

[0139] (Silicone C1-3)

[0140] A silicone having a kinematic viscosity of 1200 mm 2 / s, amino equivalent of 5000, amino group is a side chain diamino type, and is a two-end OH type amino-modified silicone.

[0141] (Silicone C1-4)

[0142] A silicone having a kinematic viscosity of 2000 mm 2 / s, amino equivalent of 7000, amino group is a side chain diamino type, and is a two-end methoxy type amino-modified silicone.

[0143] (Silicone C1-5)

[0144] A silicone having a kinematic viscosity of 250 mm 2 / s, amino equivalent of 2000, amino group is a side chain diamino type, and is a two-end blocked amino-modified silicone.

[0145] (Silicone C1-6)

[0146] A silicone having a kinematic viscosity of 1500 mm 2 / s, amino equivalent of 8000, amino group is a side chain monoamino type, and is a two-end group of a mixture of hydroxyl and methoxyl.

[0147] (Silicone C1-7)

[0148] A silicone having a kinematic viscosity of 90 mm 2 / s, amino equivalent of 2200, amino group is a two-end diamino type.

[0149] (Silicone C1-8)

[0150] A silicone having a kinematic viscosity of 300 mm 2 / s, weight ratio of dimethyl silicone main chain / ethylene oxide / propylene oxide is 50 / 20 / 30, and is a side chain type polyether-modified silicone.

[0151] (Silicone C1-9)

[0152] A silicone having a kinematic viscosity of 1000 mm 2 / s, weight ratio of dimethyl silicone main chain / ethylene oxide is 70 / 30, and is an ABn type polyether-modified silicone.

[0153] (Silicone C1-10)

[0154] A two-end blocked dimethyl silicone having a kinematic viscosity of 1000 mm 2 / s at 25°C.

[0155] (Silicone C1-11)

[0156] A two-end OH type dimethyl silicone having a kinematic viscosity of 80 mm 2 / s at 25°C.

[0157] (Non-silicone smoothing agent C2-1)

[0158] A compound obtained by reacting polybutene-based succinic anhydride having a number average molecular weight of 2000 of the polybutene portion and triethylenetetramine.

[0159] (Non-silicone smoothing agent C2-2)

[0160] A compound obtained by reacting polybutene-modified phenol having a number average molecular weight of 1500 of the polybutene portion, formaldehyde, and triethylenetetramine.

[0161] (Non-silicone smoothing agent C2-3)

[0162] A mineral oil having a kinematic viscosity of 18 mm 2 / s at 30°C, with a composition of 0.5% of aromatic component, 25% of naphthene component, and 74.5% of paraffin component.

[0163] (Non-silicone smoothing agent C2-4)

[0164] A mineral oil having a kinematic viscosity of 9 mm 2 / s at 30°C, with a composition of 2% of aromatic component, 40% of naphthene component, and 58% of paraffin component.

[0165] (Non-silicone smoothing agent C2-5)

[0166] A mineral oil having a kinematic viscosity of 46 mm 2 / s at 30°C, with a composition of 0.1% of aromatic component, 30% of naphthene component, and 69.9% of paraffin component.

[0167] (1-4) Other ingredients

[0168] As the other ingredients, the following are used.

[0169] D-1: Acetic acid

[0170] D-2: Methyl octylammonium dimethylphosphate

[0171] Diluent: Ion exchange water

[0172] (2) Preparation of the treatment agent for carbon fibers (Preparation of Example 1)

[0173] Each of 10 parts by mass of the alcohol A-1, 5 parts by mass of the nonionic surfactant B-1, 5 parts by mass of the nonionic surfactant B-4, 10 parts by mass of the nonionic surfactant B-7, and 70 parts by mass of the silicone C1-1 was weighed into a beaker. After the above-mentioned respective components were mixed well, 233 parts by mass of ion exchange water was slowly added while stirring, whereby the treatment agent for carbon fiber precursor of Example 1 was prepared.

[0174] (Preparation of other examples and comparative examples)

[0175] The treatment agent for carbon fiber precursor of each example was prepared in the same manner as in Example 1 except that the kind and parts by mass of the reagent as a mixing object were changed. The preparation conditions of all examples including Example 1 are shown in Tables 1 to 3 below.

[0176] [Evaluation of the treatment agent for carbon fiber precursor] (1) Production of carbon fibers (1-1) Production of fiber materials

[0177] A copolymer having an intrinsic viscosity of 1.80, composed of 95 parts by mass of acrylonitrile, 3.5 parts by mass of methyl acrylate, and 1.5 parts by mass of methacrylic acid, was dissolved in dimethylacetamide (DMAC) to prepare a dope having a polymer concentration of 21.0 parts by mass and a viscosity of 500 poise at 60°C. The dope was extruded from a spinneret having a pore diameter (inner diameter) of 0.075 mm and 12,000 pores at a draw ratio of 0.8 into a coagulation bath of a 70% aqueous solution of DMAC maintained at a spinning bath temperature of 35°C. The coagulated filaments were simultaneously devolatilized in a water washing tank and stretched 5 times to produce an acrylic fiber bundle in a water-swollen state.

[0178] (1-2) Production of carbon fiber precursor

[0179] The acrylic fiber bundle produced was supplied with 3% ion exchange water solution of the treatment agent for carbon fiber precursor of each example of the examples and comparative examples in an amount of 1 part by mass (excluding solvent) of the treatment agent by the impregnation method. Then, the acrylic fiber bundle to which the treatment agent was attached was subjected to a drying densification treatment with a heating roll at 150°C, and further, after being stretched 1.7 times between heating rolls at 170°C, was wound on a bobbin to obtain a carbon fiber precursor.

[0180] (2) Evaluation of the amount of scum generated

[0181] For the treatment agent of each example of the examples and comparative examples, the production of the carbon fiber precursor according to the steps of (1) above was continuously performed, and the presence or absence and the degree of scum accumulation against the heating roll in the drying densification step were observed. According to the observation results, three levels were classified as follows.

[0182] A: Little dross accumulation on the heating roll, continuous operation without cleaning for more than 7 days without stopping operation due to broken filaments, etc.

[0183] B: Although a little dross accumulation occurs on the heating roll, continuous operation without cleaning for more than 3 days and less than 7 days without stopping operation due to broken filaments, etc.

[0184] C: Much dross accumulation on the heating roll, stopping operation due to broken filaments, etc., and cleaning within less than 3 days.

[0185] (3) Evaluation of winding bunching properties

[0186] The treatment agent of each of the examples and comparative examples was classified into the following three levels according to the operation condition when the carbon fiber precursor was wound on the winder.

[0187] A: Almost no cracking, continuous winding without stopping operation.

[0188] B: Although a little cracking occurs, continuous winding without stopping operation.

[0189] C: Severe cracking of the filaments, occurrence of traverse winding, and stopping operation.

[0190] (4) Emulsion stability

[0191] A 3% ion exchange water solution of the treatment agent of each of the examples and comparative examples was circulated in an oil bath using a pump, and the state of the water solution was observed with the eye. According to the observation result, the following four levels were classified.

[0192] A: No gelation was found after 7 days, and continuous operation was possible without difficulty.

[0193] B: A little gelation was found after 7 days, but continuous operation was possible without cleaning the oil bath.

[0194] C: Gelation was found after 7 days, and the gelation in the oil bath had to be removed by cleaning, but continuous operation was possible.

[0195] D: Much gelation was produced after 7 days, and operation had to be stopped to clean the oil bath.

[0196] (5) Friction properties

[0197] A tension of 100 g weight was applied to a 12K (12,000) carbon fiber precursor bundle to which 1% of the treatment agent was attached, and the condition of the carbon fiber precursor bundle after a 1 cm chromium pear skin pin was rotated at 200 rpm for 10 minutes was observed. According to the observation result, the following three levels were classified.

[0198] A: No broken filaments and accompanying fluff were confirmed by visual observation.

[0199] B: Broken filaments and a small amount of accompanying fluff (1 to 10) were found.

[0200] C: Many broken filaments and accompanying fluff (11 or more) were found.

[0201] [Results]

[0202] The raw material compositions of each of the examples of the examples and comparative examples and the results of each evaluation are shown in Tables 1 to 3.

[0203] Table 1: Examples 1 to 12 [Table 1]

[0204]

[0205] Table 2: Examples 13 to 24 [Table 2]

[0206]

[0207] Table 3: Comparative Examples 1 to 4 [Table 3]

[0208]

[0209] [Industrial applicability]

[0210] The present application can be used, for example, in the production of carbon fiber precursors.

Claims

1. A treatment agent for a carbon fiber precursor, characterized by, which contains a saturated monoalcohol (A) having 8 or more and 26 or less carbon atoms, a nonionic surfactant (B), and a smoothing agent (C); the smoothing agent (C) contains a silicone (C1); in the nonvolatile components, the saturated monoalcohol (A) is contained in a proportion of 0.1 mass% or more and 20 mass% or less, the nonionic surfactant (B) is contained in a proportion of 10 mass% or more and 70 mass% or less, and the smoothing agent (C) is contained in a proportion of 29.9 mass% or more and 89.9 mass% or less.

2. The treatment agent for carbon fiber precursor according to claim 1, wherein the saturated monoalcohol (A) has a branched chain at the β position of a hydroxyl group.

3. The treatment agent for carbon fiber precursor according to claim 1, wherein the silicone (C1) contains an amino-modified silicone.

4. The treatment agent for carbon fiber precursor according to claim 1, wherein the nonionic surfactant (B) contains an alkylene oxide adduct (B1) of a monoalcohol having a branched chain at the β position of a hydroxyl group.

5. A carbon fiber precursor, characterized by, which has attached thereto the treatment agent for a carbon fiber precursor according to any one of claims 1 to 4.

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