JP7355367B2 - Treatment agent for carbon fiber precursor and carbon fiber precursor - Google Patents

Description

The present invention relates to a treatment agent for carbon fiber precursors and a carbon fiber precursor that can improve the strength of carbon fibers.

In general, carbon fibers are widely used as carbon fiber composite materials in combination with matrix resins such as epoxy resins in various fields such as building materials and transportation equipment. Usually, carbon fibers are produced as carbon fiber precursors through, for example, a step of spinning acrylic fibers, a step of drawing the fibers, a flame-retardant treatment step, and a carbonization treatment step. A treatment agent for carbon fiber precursors may be used for carbon fiber precursors in order to suppress adhesion or fusion between fibers that occurs during the carbon fiber manufacturing process.

Conventionally, a treatment agent for carbon fiber precursors disclosed in Patent Document 1 is known. Patent Document 1 discloses that the compound is compatible with hydroxybenzoic acid ester, amino-modified silicone, and hydroxybenzoic acid ester, and has a residual mass ratio R1 of 70 to 100% by mass at 300°C in thermal mass spectrometry in an air atmosphere. An oil agent for carbon fiber precursor acrylic fibers containing an organic compound that is liquid at ℃ is disclosed.

JP2016-56497A

However, the conventional treatment agents for carbon fiber precursors have a problem in that the strength of the carbon fibers finally obtained is still insufficient.
The problem to be solved by the present invention is to provide a treatment agent for carbon fiber precursors and a carbon fiber precursor that can improve the strength of carbon fibers.

As a result of research aimed at solving the above-mentioned problems, the present inventors have discovered that carbon fiber precursors to which a carbon fiber precursor treatment agent containing an aromatic compound and a nonionic surfactant is attached are treated under certain conditions. It has been found that a treatment agent for carbon fiber precursors whose residual rate after firing is defined within a specific range is truly suitable.

In order to solve the above problems, a treatment agent for carbon fiber precursor according to one aspect of the present invention is a treatment agent for carbon fiber precursor containing an aromatic compound and a nonionic surfactant, The precursor processing agent satisfies 0≦X1≦0.3, 0.1≦X2≦0.4, and 0.2≦X3≦0.5 in the following Equations 1 to 3,
The aromatic compound is an ester of a carboxylic acid and a compound to which alkylene oxide is added at a ratio of 0.1 mol or more and less than 2.5 mol to 1 mol of bisphenol A , and 2 mol of alkylene oxide to 1 mol of bisphenol A. Contains a combination of an ester of a compound and a carboxylic acid added in a ratio of .5 moles or more and 6 moles or less,
The nonionic surfactant is a compound obtained by adding an alkylene oxide having 2 to 4 carbon atoms to an organic acid, an organic alcohol, an organic amine and/or an organic amide, a polyoxyalkylene polyhydric alcohol fatty acid ester type nonionic surfactant, and at least one selected from polyoxyalkylene fatty acid amide type nonionic surfactants,
When the total content of the aromatic compound and the nonionic surfactant is 100 parts by mass, the content of the aromatic compound is 5 to 90 parts by mass.

(In the above numbers 1 to 3,
W1: mass per 1 m of carbon fiber precursor A in which the amount of the carbon fiber precursor treatment agent attached is 1% by mass,
W2: mass per meter of flame-resistant fiber after firing the carbon fiber precursor A at 200° C. in an air atmosphere for 30 minutes with a load of 0.12 g per single yarn;
W3: mass per meter of flame-resistant fiber after firing the carbon fiber precursor A at 220° C. in an air atmosphere for 1 hour with a load of 0.15 g per single yarn;
W4: Mass per meter of flame-resistant fiber after firing the carbon fiber precursor A at 240° C. in an air atmosphere for 2 hours with a load of 0.15 g per single yarn. )
It is preferable that the carbon fiber precursor treatment agent further contains silicone.

The carbon fiber precursor treatment agent has a content ratio of 5 to 95 parts by weight, when the total content ratio of the aromatic compound, the nonionic surfactant, and the silicone is 100 parts by mass. Parts by mass are preferred.

The treatment agent for carbon fiber precursor has a Ti element concentration of 200 ppm or less detected from the treatment agent for carbon fiber precursor by high-frequency inductively coupled plasma emission spectroscopy, and the concentration of Ti element detected from the treatment agent for carbon fiber precursor by ion chromatography is 200 ppm or less. It is preferable that the concentration of sulfate ions detected from the treatment agent is 200 ppm or less, and the concentration of phosphate ions detected from the treatment agent is 200 ppm or less.

In order to solve the above problems, a carbon fiber precursor according to another aspect of the present invention is characterized in that the carbon fiber precursor treatment agent described above is attached.

According to the present invention, the strength of carbon fibers can be improved.

(First embodiment)
Hereinafter, a first embodiment of the carbon fiber precursor treatment agent (hereinafter simply referred to as treatment agent) of the present invention will be described. The processing agent of this embodiment contains an aromatic compound and a nonionic surfactant. The aromatic compound constituting the aromatic compound is not particularly limited, but is preferably a benzene aromatic compound, and may be either a monocyclic compound or a polycyclic compound. Specific examples of monocyclic compounds include aromatic monocarboxylic acids such as benzoic acid, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, and 5-sulfoisophthalic acid. . In the present invention , the aromatic compound is an ester of a carboxylic acid and a compound added at a ratio of 0.1 mol or more and less than 2.5 mol of alkylene oxide to 1 mol of bisphenol A, and an alkylene oxide to 1 mol of bisphenol A. A configuration including a combination of an ester of a carboxylic acid and a compound added at a ratio of 2.5 moles or more and 6 moles or less of oxide is adopted.

The polycyclic compound may be a compound having a structure in which two or more rings are separate, or may be a fused ring compound. Specific examples of compounds having a structure in which two or more rings are separate include bisphenol A, AP, AF, B, BP, C, E, F, G, M, S, P, PH, TMC, Examples include bisphenols such as Z. Among these specific examples, bisphenol A is preferred.

The aromatic compounds to be used in the treatment agent of this embodiment include a compound obtained by adding an alkylene oxide to the above-mentioned aromatic compound, a compound obtained by adding an alkylene oxide to the above-mentioned aromatic compound, and a (poly) compound of a carboxylic acid. Esterified compounds, ester compounds of the above-mentioned aromatic monocarboxylic acids or aromatic dicarboxylic acids and aliphatic alcohols are preferred. By using such a compound, the effects of the present invention can be further improved.

Specific examples of the alkylene oxide used in the compound obtained by adding alkylene oxide to an aromatic compound include ethylene oxide, propylene oxide, butylene oxide, and the like. Among these, ethylene oxide is preferred. Further, the number of moles of alkylene oxide added per mole of the aromatic compound is appropriately set, but is preferably 0.1 to 50 moles, more preferably 1 to 20 moles, and even more preferably 2 to 10 moles. Note that the number of moles of alkylene oxide added indicates the number of moles of alkylene oxide per mole of aromatic compound in the raw material.

Examples of the carboxylic acid used in the (poly)esterification of a compound obtained by adding an alkylene oxide to an aromatic compound and a carboxylic acid include aliphatic carboxylic acids, aromatic carboxylic acids, and the like. The carboxylic acid may be a monocarboxylic acid or a polyhydric carboxylic acid, and may also have a hydroxy group. In the case of aliphatic carboxylic acids, they may be saturated or unsaturated fatty acids, and may be linear or branched.

Specific examples of aliphatic monocarboxylic acids include pentanoic acid, hexanoic acid, octanoic acid, 2-ethylhexanoic acid, octylic acid, decanoic acid, dodecanoic acid (lauric acid), tridecanoic acid, isotridecanoic acid, hexadecanoic acid, and octadecane. Acid (stearic acid), isooctadecanoic acid (isostearic acid), hydroxyoctadecanoic acid, 12-hydroxyoctadecanoic acid (12-hydroxystearic acid), octadecenoic acid, hydroxyoctadecenoic acid, octadecadienoic acid, octadectrienoic acid, docosane Examples include acid (behenic acid), tetracosanoic acid, hexacosanoic acid, octadocosanoic acid, octacosanoic acid, ricinoleic acid, oleic acid, and the like.

Specific examples of aliphatic dicarboxylic acids include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, and the like.

Specific examples of aromatic carboxylic acids include aromatic monocarboxylic acids such as benzoic acid, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, and 5-sulfoisophthalic acid. .

As specific examples of the aromatic monocarboxylic acid or aromatic dicarboxylic acid constituting the ester compound of aromatic monocarboxylic acid or aromatic dicarboxylic acid and aliphatic alcohol, those mentioned above can be appropriately employed. Specific examples of aliphatic alcohols constituting the ester compound of aromatic monocarboxylic acid or aromatic dicarboxylic acid and aliphatic alcohol include methyl alcohol, butyl alcohol, octyl alcohol, nonanol, lauryl alcohol, stearyl alcohol, ceryl alcohol, Isobutyl alcohol, 2-ethylhexyl alcohol, isododecyl alcohol, isohexadecyl alcohol, isostearyl alcohol, isotetracosanyl alcohol, 2-propyl alcohol, 12-eicosyl alcohol, vinyl alcohol, butenyl alcohol, hexadecenyl alcohol , oleyl alcohol, eicosenyl alcohol, 2-methyl-2-propylene-1-ol, 6-ethyl-2-undecen-1-ol, 2-octen-5-ol, 15-hexadecen-2-ol, etc. Examples include monohydric aliphatic alcohols. Specific examples of ester compounds of aromatic monocarboxylic acids or aromatic dicarboxylic acids and aliphatic alcohols include aromatic dicarboxylic acids such as dioctyl phthalic acid, dimethyl terephthalic acid, dimethyl isophthalic acid, and dimethyl-2,6-naphthalene dicarboxylic acid. Examples include ester compounds of acids and monovalent aliphatic alcohols.

The above-mentioned aromatic compounds may be used alone or in an appropriate combination of two or more aromatic compounds.
Among these aromatic compounds, preferred are compounds obtained by adding alkylene oxide to bisphenol, and (poly)esters of carboxylic acids and compounds obtained by adding alkylene oxide to bisphenol. Such a compound further improves the effects of the present invention, particularly the effects on spinning convergence.

Furthermore, among these aromatic compounds, esters of carboxylic acids and compounds to which alkylene oxide is added at a ratio of 0.1 mole or more and less than 2.5 moles to 1 mole of bisphenol A, and It is more preferable to use an ester of a carboxylic acid and a compound to which alkylene oxide is added in a ratio of 2.5 moles or more and 6 moles or less. By including such a compound, the effects of the present invention, particularly smoothness, are further improved.

Examples of the nonionic surfactant include known ones. Specific examples of nonionic surfactants include (1) compounds obtained by adding alkylene oxides having 2 to 4 carbon atoms to organic acids, organic alcohols, organic amines, and/or organic amides, such as polyoxyethylene dilauric acid esters; , polyoxyethylene oleate, polyoxyethylene laurate methyl ether, polyoxyethylene oleate diester, polyoxyethylene octyl ether, polyoxyethylene lauryl ether, polyoxyethylene lauryl ether methyl ether, polyoxyethylene polyoxypropylene Lauryl ether, polyoxypropylene lauryl ether methyl ether, polyoxybutylene oleyl ether, polyoxyethylene polyoxypropylene nonyl ether, polyoxyethylene isononyl ether, polyoxypropylene nonyl ether, polyoxyethylene polyoxypropylene octyl ether, polyoxy Ether-type nonionic interfaces such as ethylene dodecyl ether, polyoxyethylene tridecyl ether, polyoxyethylene polyoxypropylene tetradecyl ether, polyoxyethylene lauryl amino ether, polyoxyethylene lauramide ether, polyoxyethylene tristyrenated phenyl ether, etc. activator, (2) polyhydric alcohol partial ester type nonionic surfactant such as sorbitan trioleate, sorbitan monooleate, sorbitan monostearate, glycerin monolaurelate, (3) polyoxyalkylene sorbitan trioleate, poly Oxyalkylene coconut oil, polyoxyalkylene castor oil, polyoxyalkylene hydrogenated castor oil, polyoxyalkylene hydrogenated castor oil trioctanoate, maleic ester, stearic ester, or oleic ester of polyoxyalkylene hydrogenated castor oil, etc. polyoxyalkylene polyhydric alcohol fatty acid ester type nonionic surfactant, (4) alkylamide type nonionic surfactant such as diethanolamine monolauramide, (5) polyoxyethylene diethanolamine monooleylamide, polyoxyethylene laurylamine, Examples include polyoxyalkylene fatty acid amide type nonionic surfactants such as polyoxyethylene tallow amine. As the above-mentioned nonionic surfactants, one type of nonionic surfactant may be used alone, or two or more types of nonionic surfactants may be used in an appropriate combination. Among these nonionic surfactants, ether type nonionic surfactants are preferred because they are excellent in the effects of the present invention. In the present invention, as the nonionic surfactant, a compound obtained by adding an alkylene oxide having 2 to 4 carbon atoms to an organic acid, an organic alcohol, an organic amine and/or an organic amide, a polyoxyalkylene polyhydric alcohol fatty acid ester type nonionic A configuration containing at least one selected from a surfactant and a polyoxyalkylene fatty acid amide type nonionic surfactant is adopted.

In the treatment agent of this embodiment, when the total content of the aromatic compound and the nonionic surfactant is 100 parts by mass, the content of the aromatic compound is 5 to 90 parts by mass, preferably It is 50 to 85 parts by mass. By defining it within this range, the effects of the present invention can be further improved.

The processing agent of this embodiment can further contain silicone. By blending this silicone, the effects of the present invention, particularly the strength of carbon fibers, are further improved. Specific examples of silicones include dimethyl silicone, phenyl-modified silicone, amino-modified silicone, amide-modified silicone, polyether-modified silicone, aminopolyether-modified silicone, alkyl-modified silicone, alkylaralkyl-modified silicone, alkylpolyether-modified silicone, and ester. Examples include modified silicone, epoxy-modified silicone, carbinol-modified silicone, mercapto-modified silicone, and polyoxyalkylene-modified silicone. As for the silicone, one type of silicone may be used alone, or two or more types of silicone may be used in an appropriate combination. Among these, amino-modified silicones are preferred.

The lower limit of the kinematic viscosity at 25° C. of the amino-modified silicone is not particularly limited, but is preferably 50 mm ² /s or more, more preferably 100 mm ² /s or more. The upper limit of the kinematic viscosity at 25° C. of the amino-modified silicone is not particularly limited, but is preferably 10,000 mm ² /s or less, more preferably 5,000 mm ² /s or less.

In the treatment agent of this embodiment, the content ratio of the aromatic compound, the nonionic surfactant, and the silicone is not particularly limited, but the content ratio of the aromatic compound, the nonionic surfactant, and the silicone is not particularly limited. When the total content of the aromatic compound is 100 parts by weight, the content of the aromatic compound is preferably 5 to 95 parts by weight, more preferably 15 to 70 parts by weight. By defining it within this range, the effects of the present invention can be further improved.

In the treatment agent of this embodiment, the concentration of Ti element detected by high-frequency inductively coupled plasma emission spectrometry is preferably 200 ppm or less, more preferably 100 ppm or less, and even more preferably 50 ppm or less. Furthermore, the concentration of sulfate ions in the treatment agent detected by ion chromatography is preferably 200 ppm or less, more preferably 100 ppm or less, and still more preferably 50 ppm or less. The concentration of phosphate ions is preferably 200 ppm or less, more preferably 100 ppm or less, even more preferably 50 ppm or less. By regulating the respective concentrations of Ti element, sulfate ion, and phosphate ion in the treatment agent within such ranges, the effects of the present invention, particularly the effect of preventing fiber fusion, are improved. Note that the respective concentrations of Ti element, sulfate ion, and phosphate ion in the processing agent indicate the concentration in the nonvolatile matter not containing the solvent.

In the processing agent of this embodiment, X1 to X3 shown in Equations 4 to 6 below are 0≦X1≦0.3, 0.1≦X2≦0.4, and 0.2≦X3≦0. It is necessary to satisfy the relationship 5. By specifying each numerical value range of X1 to X3, the effects of the present invention are improved.

W1 in the above numbers 4 to 6 indicates the mass per 1 m of the carbon fiber precursor A to which the amount of the treatment agent attached is 1% by mass.

W2 in the above equation 4 indicates the mass per meter of flame-resistant fiber after the carbon fiber precursor A is fired at 200° C. in an air atmosphere for 30 minutes under a load of 0.12 g per single fiber. More specifically, carbon fiber precursor A was heated from room temperature at a rate of 5° C./min, and after reaching 200° C., it was fired for 30 minutes.

W3 in the above equation 5 indicates the mass per meter of flame-resistant fiber after the carbon fiber precursor A is fired at 220° C. in an air atmosphere for 1 hour under a load of 0.15 g per single yarn. More specifically, carbon fiber precursor A was heated from room temperature at a rate of 5° C./min, and after reaching 220° C., it was fired for 1 hour.

W4 in the above equation 6 indicates the mass per meter of flame-resistant fiber after the carbon fiber precursor A is fired at 240° C. in an air atmosphere for 2 hours under a load of 0.15 g per single yarn. More specifically, carbon fiber precursor A was heated from room temperature at a rate of 5° C./min, and after reaching 240° C., it was fired for 2 hours.

Note that X1 to X3 above can be adjusted by, for example, changing the combination or content of the aromatic compound, nonionic surfactant, and silicone. For example, the aromatic compound, nonionic surfactant, and silicone can be adjusted by selecting preferred types or by specifying the blending amount within a preferred range. It can also be adjusted by reducing the concentration of impurities in the processing agent. For example, the concentration can be adjusted by regulating the concentrations of Ti element, sulfate ion, and phosphate ion in the treatment agent within the above-mentioned preferred ranges.

(Second embodiment)
Next, a second embodiment of the carbon fiber precursor according to the present invention will be described. In the carbon fiber precursor of this embodiment, the treatment agent of the first embodiment is attached to the carbon fiber precursor.

In the method for manufacturing carbon fiber using the carbon fiber precursor of this embodiment, first, the above-mentioned treatment agent is attached to the raw material fiber of the carbon fiber precursor to obtain the carbon fiber precursor, and then a silk-spinning process is performed. be exposed. Next, a flame-retardant treatment step is performed in which the carbon fiber precursor produced in the spinning process is converted into a flame-retardant fiber in an oxidizing atmosphere at 200-300°C, preferably 230-270°C, and the flame-retardant fiber is further processed. A carbonization treatment step is performed in an inert atmosphere at 300 to 2000°C, preferably 300 to 1300°C.

The yarn spinning process is a process of spinning a carbon fiber precursor obtained by attaching the treatment agent of the first embodiment to the raw material fiber of the carbon fiber precursor, and includes an attachment treatment process and a stretching process.
The attachment treatment step is a step of attaching a treatment agent to the fibers of the carbon fiber precursor after spinning them. That is, the treatment agent is attached to the raw material fiber of the carbon fiber precursor in the attachment treatment step. The raw material fibers of this carbon fiber precursor are drawn immediately after spinning, and the high-magnification drawing after the adhesion treatment process is particularly referred to as the "drawing process." The stretching process may be a wet heat stretching method using high temperature steam or a dry heat stretching method using a hot roller.

Examples of raw material fibers for the carbon fiber precursor include acrylic fibers. The acrylic fibers are preferably composed of fibers whose main component is polyacrylonitrile obtained by copolymerizing at least 90 mol% or more of acrylonitrile and 10 mol% or less of a flame resistance promoting component. As the flame resistance promoting component, for example, a vinyl group-containing compound that is copolymerizable with acrylonitrile can be suitably used. The single fiber fineness of the carbon fiber precursor is not particularly limited, but from the viewpoint of balance between performance and manufacturing cost, it is preferably 0.1 to 2.0 dTex. Further, there is no particular limitation on the number of single fibers constituting the fiber bundle of the carbon fiber precursor, but from the viewpoint of balance between performance and manufacturing cost, it is preferably 1,000 to 96,000.

Although the treatment agent may be attached to the raw material fiber of the carbon fiber precursor at any stage of the spinning process, it is preferable to attach it once before the drawing process. Further, it may be attached at any stage before the stretching process. For example, it may be attached immediately after spinning. Furthermore, it may be reattached at any stage after the stretching process. For example, it may be attached again immediately after the stretching process, it may be attached again at the winding stage, or it may be attached again immediately before the flameproofing process. During the spinning process, the number of times the adhesive is attached is not particularly limited.

There is no particular restriction on the proportion of the treatment agent of the first embodiment to be attached to the carbon fiber precursor, but the treatment agent (not including a solvent) should be attached in an amount of 0.1 to 2% by mass relative to the carbon fiber precursor. It is preferable that the amount is 0.3 to 1.2% by mass, and more preferably 0.3 to 1.2% by mass. This configuration further improves the effects of the present invention. As a method for applying the treatment agent in the first embodiment, known methods can be applied, such as a spray lubrication method, an immersion lubrication method, a roller lubrication method, a guide lubrication method using a metering pump, and the like. Examples of the form in which the treatment agent of the first embodiment is applied to the fibers include an organic solvent solution, an aqueous liquid, and the like.

The actions and effects of the processing agent and carbon fiber precursor of this embodiment will be explained.
(1) In this embodiment, the strength of the carbon fiber finally obtained can be improved. Further, it is possible to prevent the carbon fibers finally obtained from fusing. Furthermore, the cohesiveness and smoothness of the carbon fiber precursor to which the treatment agent has been applied can be improved.

Note that the above embodiment may be modified as follows.
・The processing agent of this embodiment may contain binders, antioxidants, ultraviolet absorbers, etc. as stabilizers and antistatic agents to maintain the quality of the processing agent, within a range that does not impede the effects of the present invention. Components commonly used in processing agents may be further blended.

Examples will be given below to make the structure and effects of the present invention more specific, but the present invention is not limited to these Examples. In the Examples and Comparative Examples below, parts mean parts by mass, and % means % by mass.

Aromatic compounds used in the present examples and comparative examples are shown in Tables 1 to 4. The aromatic compounds listed in Table 1 are esters of bisphenol A with 2 moles of alkylene oxide and carboxylic acid. The aromatic compounds listed in Table 2 are esters of a 3-mole alkylene oxide adduct of bisphenol A and a carboxylic acid. The aromatic compounds listed in Table 3 are alkylene oxide adducts of bisphenol A. The aromatic compounds listed in Table 4 are compounds obtained by esterifying 2 moles of a compound obtained by adding 2 to 10 moles of ethylene oxide to 1 mole of bisphenol A with 3 moles of carboxylic acid.

The type of aromatic compound, the type of alkylene oxide, the number of moles of alkylene oxide added (mole ratio), and the type of carboxylic acid constituting each aromatic compound are listed in the "Type of aromatic compound" column of Tables 1 to 4. As shown in the "Type of alkylene oxide" column, "Number of moles of alkylene oxide added" column, and "Type of carboxylic acid" column.

In Table 1,
A-1: A compound obtained by esterifying 1 mole of a compound obtained by adding 2 moles of ethylene oxide to 1 mole of bisphenol A with 2 moles of octylic acid,
A-2: A compound obtained by esterifying 1 mole of a compound obtained by adding 0.2 moles of ethylene oxide to 1 mole of bisphenol A with 2 moles of oleic acid,
A-3: A compound obtained by esterifying 1 mole of a compound obtained by adding 2.2 moles of ethylene oxide to 1 mole of bisphenol A with 2 moles of lauric acid,
A-4: A compound obtained by esterifying 1 mole of a compound obtained by adding 2 moles of propylene oxide to 1 mole of bisphenol A with 2 moles of octylic acid,
shows.

In Table 2,
B-1: A compound obtained by esterifying 1 mole of a compound obtained by adding 3 moles of ethylene oxide to 1 mole of bisphenol A with 2 moles of octylic acid,
B-2: A compound obtained by esterifying 1 mole of a compound obtained by adding 2.6 moles of ethylene oxide to 1 mole of bisphenol A with 2 moles of oleic acid,
B-3: A compound obtained by esterifying 1 mole of a compound obtained by adding 5 moles of ethylene oxide to 1 mole of bisphenol A with 2 moles of lauric acid,
B-4: A compound obtained by esterifying 1 mole of a compound obtained by adding 3 moles of propylene oxide to 1 mole of bisphenol A with 2 moles of octylic acid,
shows.

In Table 3,
C-1: a compound obtained by adding 4 moles of ethylene oxide to 1 mole of bisphenol A,
C-2: a compound obtained by adding 10 moles of ethylene oxide to 1 mole of bisphenol A,
C-3: compound in which 18 moles of ethylene oxide is added to 1 mole of bisphenol A,
C-4: a compound obtained by adding 4 moles of propylene oxide to 1 mole of bisphenol A,
shows.

In Table 4,
D-1: A compound obtained by esterifying 2 moles of a compound obtained by adding 2 moles of ethylene oxide to 1 mole of bisphenol A with 1 mole of adipic acid and 2 moles of lauric acid,
D-2: A compound obtained by esterifying 2 moles of a compound obtained by adding 4 moles of ethylene oxide to 1 mole of bisphenol A with 1 mole of adipic acid and 2 moles of lauric acid,
D-3: A compound obtained by esterifying 2 moles of a compound obtained by adding 10 moles of ethylene oxide to 1 mole of bisphenol A with 1 mole of adipic acid and 2 moles of stearic acid,
shows.

Test Category 1 (Preparation of treatment agent for carbon fiber precursor)
The treatment agent for carbon fiber precursor of Example 1 consisted of 130 g of compound (A-1), which was obtained by esterifying 1 mole of a compound obtained by adding 2 moles of ethylene oxide to 1 mole of bisphenol A with 2 moles of octylic acid, and 1 mole of bisphenol A with ethylene oxide. 20 g of compound (B-1) esterified with 2 moles of octylic acid to 1 mole of the compound added with 3 moles, 500 g of amino-modified silicone (F-1) having a viscosity of 2000 mm ² /s and an amino equivalent weight of 2000, and 1 mole of tetradecyl alcohol. 10 moles of ethylene oxide, 250 g of a 6 mole adduct of propylene oxide (G-1), and 100 g of a 10 mole adduct of dodecyl alcohol with ethylene oxide (G-2) were added to a beaker and mixed well. A 30% aqueous solution of the carbon fiber precursor treatment agent of Example 1 was prepared by gradually adding ion-exchanged water while continuing stirring so that the solid content concentration was 30%.

Each carbon fiber precursor treatment agent of Examples 2 to 8 , Reference Examples 9 to 20, and Comparative Examples 1 to 6 was prepared in the same manner as in Example 1 using each component shown in Table 5. .
The types and contents of aromatic compounds, types and contents of silicones, types and contents of nonionic surfactants, and types and contents of other compounds in the treatment agents for carbon fiber precursors in each example are shown in the table below. As shown in the "Aromatic compounds" column, "Silicone" column, "Nonionic surfactant" column, and "Other compounds" column of No. 5.

In addition, the concentration of Ti element, the concentration of sulfate ion, and the concentration of phosphate ion in the nonvolatile content of the treatment agent for carbon fiber precursor of each example were determined in the "Ti element" column, "sulfate ion" column, and "phosphorus ion" column in Table 5. Shown in the "Acid ions" column. Note that the concentration of Ti element was measured by high frequency inductively coupled plasma emission spectrometry. The concentration of sulfate ions and the concentration of phosphate ions were measured by ion chromatography.

In addition, the values of X1 to X3 determined by the above-mentioned Equations 4 to 6 for each example of the carbon fiber precursor treatment agent are shown in the "X1, X2, X3" column of Table 5.

In Table 5,
*1: Percentage of aromatic compounds in the carbon fiber precursor treatment agent excluding volatile content (mass ratio),
E-1: dioctyl phthalate,
F-1: amino-modified silicone with a viscosity of 2000 mm ² /s and an amino equivalent of 2000,
F-2: amino-modified silicone with a viscosity of 300 mm ² /s and an amino equivalent of 4000,
F-3: amino-modified silicone with a viscosity of 600 mm ² /s and an amino equivalent of 1500,
F-4: amino-modified silicone with a viscosity of 5000 mm ² /s and an amino equivalent of 8000,
G-1: 10 moles of ethylene oxide and 6 moles of propylene oxide adduct of tetradecyl alcohol,
G-2: 10 mol ethylene oxide adduct of dodecyl alcohol,
G-3: 8 mol ethylene oxide adduct of isononyl alcohol,
H-1: 1-ethyl-2-(heptadecenyl)-4,5-dihydro-3-(2-hydroxyethyl)-1H-imidazolinium ethyl sulfate,
H-2: potassium salt of isododecyl phosphate,
H-3: pentaerythritol tetraoleyl ester,
H-4: silicone resin fine particles with an average particle diameter of 0.5 μm,
shows.

Test category 2 (manufacture of carbon fiber precursor and carbon fiber)
Using the carbon fiber precursor treatment agent prepared in Test Section 1, carbon fiber precursors and carbon fibers were manufactured.

A copolymer with an intrinsic viscosity of 1.80 consisting of 95% by mass of acrylonitrile, 3.5% by mass of methyl acrylate, and 1.5% by mass of methacrylic acid is dissolved in dimethylacetamide (DMAC) to obtain a polymer concentration of 21.0% by mass. %, and a viscosity of 500 poise at 60° C. was prepared. The spinning stock solution was discharged at a draft ratio of 0.8 from a spinneret with a hole diameter (inner diameter) of 0.075 mm and a number of holes of 12,000 into a coagulation bath of a 70% by mass aqueous solution of DMAC maintained at a spinning bath temperature of 35°C.

The coagulated thread was desolvated and simultaneously stretched five times in a water washing tank to produce a water-swollen acrylic fiber strand. This was soaked in a 4% ion-exchange aqueous solution of the carbon fiber precursor treatment agent prepared in Test Category 2 so that the amount of carbon fiber precursor treatment agent deposited was 1% by mass (not including solvent). I refueled. Thereafter, this acrylic fiber strand was dried and densified using heated rollers at 130°C, then stretched 1.7 times between heated rollers at 170°C, and then wound around a yarn tube to form a carbon fiber precursor. Obtained. The yarn was unwound from this carbon fiber precursor, and after being subjected to flameproofing treatment in an air atmosphere for 1 hour in a flameproofing furnace with a temperature gradient of 230 to 270℃, it was continuously heated to 300 to 1,300℃ in a nitrogen atmosphere. The carbon fibers were converted into carbon fibers by firing in a carbonization furnace with a temperature gradient, and then wound into a thread tube.

In addition to the strength and fusion of the carbon fibers, the convergence (spinning convergence) and smoothness in the spinning process were evaluated as shown below. The results are shown in the "Strength" column, "Fusion" column, "Spinning convergence" column, and "Smoothness" column of Table 5.

Test category 3 (evaluation)
- Strength The strength of the carbon fiber obtained above was measured according to JIS R7606 (2000). Note that JIS R7606 (2000) corresponds to ISO11566, Carbon fiber-Determination of the tensile properties the single-filament specimens, which was published as the first edition in 1996, and the technical contents of both are equivalent.
◎ (Excellent): 4.0 GPa or more.
○ (Good): 3.5 GPa or more and less than 4.0 GPa.
× (Poor): Less than 3.5 GPa.

-Fusion 10 points were randomly selected from the carbon fibers obtained in Test Category 2, 1 cm short fibers were cut out, and the state of fusion was visually observed and evaluated using the following criteria.
◎ (Excellent): No fusion.
○ (Good): Fusion was present in one or more and less than five locations.
× (Poor): There are 5 or more fusions.

・Spinning convergence In the process from after oiling the acrylic fiber strand shown in test category 2 with the treatment agent for carbon fiber precursor to winding it as a carbon fiber precursor, the degree of entanglement of the yarn was visually observed, and the following The spinning convergence was evaluated based on the standard.
◎ (Excellent): All yarns passed through the process smoothly without yarn breakage.
○ (Good): There was some yarn cracking, but the yarn passed through the process smoothly.
× (Poor): Problems were observed in production as the single yarn was wrapped around the heating roller and yarn breakage was observed before winding.

・Smoothness A 50g weight is hung on the carbon fiber precursor obtained in the test section, a tension meter is set on the opposite side, and a 1cm diameter chromium satin pin is placed between the weight and the tensionmeter at an angle of 135°C. The tension when rubbed by rotating at a speed of 10 m/min was measured and evaluated based on the following criteria.
◎ (Excellent): Less than 60g.
○ (Good): 60 g or more and less than 65 g.
× (defective): 65g or more.

As is clear from the evaluation results of each Example with respect to each Comparative Example in Table 5, the treatment agent of the present invention can improve the strength of carbon fibers and prevent carbon fibers from being fused together. Furthermore, the cohesiveness and smoothness of the carbon fiber precursor to which the treatment agent has been applied can be improved.

Claims (5)

A carbon fiber precursor treatment agent containing an aromatic compound and a nonionic surfactant,
The carbon fiber precursor treatment agent satisfies 0≦X1≦0.3, 0.1≦X2≦0.4, and 0.2≦X3≦0.5 in the following Equations 1 to 3,
The aromatic compound is an ester of a carboxylic acid and a compound to which alkylene oxide is added at a ratio of 0.1 mol or more and less than 2.5 mol to 1 mol of bisphenol A , and 2 mol of alkylene oxide to 1 mol of bisphenol A. Contains a combination of an ester of a compound and a carboxylic acid added in a ratio of .5 moles or more and 6 moles or less,
The nonionic surfactant is a compound obtained by adding an alkylene oxide having 2 to 4 carbon atoms to an organic acid, an organic alcohol, an organic amine and/or an organic amide, a polyoxyalkylene polyhydric alcohol fatty acid ester type nonionic surfactant, and at least one selected from polyoxyalkylene fatty acid amide type nonionic surfactants,
A carbon fiber precursor characterized in that the content ratio of the aromatic compound is 5 to 90 parts by mass when the total content ratio of the aromatic compound and the nonionic surfactant is 100 parts by mass. Treatment agent.
(In the above numbers 1 to 3,
W1: mass per 1 m of carbon fiber precursor A in which the amount of the carbon fiber precursor treatment agent attached is 1% by mass,
W2: mass per meter of flame-resistant fiber after firing the carbon fiber precursor A at 200° C. in an air atmosphere for 30 minutes with a load of 0.12 g per single yarn;
W3: mass per meter of flame-resistant fiber after firing the carbon fiber precursor A at 220° C. in an air atmosphere for 1 hour with a load of 0.15 g per single yarn;
W4: Mass per meter of flame-resistant fiber after firing the carbon fiber precursor A at 240° C. in an air atmosphere for 2 hours with a load of 0.15 g per single yarn. ) The carbon fiber precursor treatment agent according to claim 1, further comprising silicone. 3. The aromatic compound according to claim 2, wherein the content of the aromatic compound is 5 to 95 parts by mass when the total content of the aromatic compound, the nonionic surfactant, and the silicone is 100 parts by mass. Treatment agent for carbon fiber precursors. The concentration of Ti element detected in the treatment agent for carbon fiber precursor by high frequency inductively coupled plasma emission spectroscopy is 200 ppm or less,
The carbon fiber precursor according to any one of claims 1 to 3, wherein the concentration of sulfate ions detected from the treatment agent for carbon fiber precursor by ion chromatography is 200 ppm or less, and the concentration of phosphate ions is 200 ppm or less. Body treatment agent. A carbon fiber precursor, characterized in that the treatment agent for carbon fiber precursor according to any one of claims 1 to 4 is attached thereto.