TWI774738B - Acrylic fiber treatment agent and use thereof - Google Patents

Abstract

The present invention provides an acrylic fiber treatment agent capable of suppressing deterioration of acrylic fiber for producing carbon fiber when acrylic fiber for producing carbon fiber produced by applying treatment agent is stored for a long period of time; also provided are an acrylic fiber for producing carbon fiber using the treatment agent and a method for producing carbon fiber using the treatment agent.

The acrylic fiber treatment agent of the present invention contains an amino-modified silicone (A), a Bronsted acid compound (B) and an acetylene type surfactant (C). The acrylic fiber for producing carbon fiber of the present invention is obtained by attaching the acrylic fiber treating agent of the present invention to raw acrylic fiber of acrylic fiber for producing carbon fiber.

Description

Acrylic fiber treatment agent and its use

The present invention relates to an acrylic fiber treatment agent and its use. More specifically, it relates to a treatment agent used in the production of acrylic fibers, acrylic fibers for carbon fiber production using the treatment agent (hereinafter sometimes referred to as precursors), and production of carbon fibers using the treatment agent method.

Carbon fibers are used as reinforcing fibers for composite materials with plastics called matrix resins by utilizing their excellent mechanical properties, and are widely used in aerospace applications, sports applications, and general industrial applications.

As a method of producing carbon fiber, first, an acrylic fiber for carbon fiber production (sometimes referred to as a precursor) is produced (the production step of producing this precursor is sometimes referred to as a spinning step). Generally, the precursor is converted into flame-resistant fibers in an oxidizing environment at 200 to 300°C (hereinafter this step is sometimes referred to as a flame-resistant treatment step), followed by carbonization in an inert environment at 300 to 2000°C (Hereinafter, this step may be referred to as a carbonization treatment step) method (hereinafter, the flame resistance treatment step and the carbonization treatment step may be combined and referred to as a firing step). In the production of this precursor, it is subjected to a drawing step of drawing at a higher magnification than general acrylic fibers. At this time, the fibers tend to stick to each other, and the high-magnification stretching cannot be performed uniformly, so that it becomes a non-uniform precursor. A carbon fiber obtained by firing such a precursor has a problem that sufficient strength cannot be obtained. In addition, when the precursor is fired, there is a problem that the single fibers adhere to each other, and the quality and level of the obtained carbon fibers are degraded.

In order to prevent sticking of precursors and prevent adhesion of carbon fibers, as a treatment agent applied to the precursors, silicon-based materials with low fiber-to-fiber friction and excellent releasability under wet conditions and high temperature environments have been proposed. A technology of applying a treatment agent (especially an amine-modified silicone-based treatment agent that can further improve heat resistance by a cross-linking reaction by heating) to a precursor (refer to a patent References 1 to 2).

When the precursor produced by applying such a treatment agent is stored for a long period of time, there is a problem that the precursor deteriorates with time. Therefore, when the precursor after long-term storage is fired to produce carbon fibers, there are problems such as generation of fluff in the firing step, and a reduction in the strength of the carbon fibers after firing.

[Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Application Laid-Open No. 2001-172879

[Patent Document 2] Japanese Patent Laid-Open No. 2002-129481

In view of the related prior art background, the object of the present invention is to provide a treatment agent for acrylic fiber, which can suppress the acrylic fiber for carbon fiber production after the acrylic fiber for carbon fiber production produced by applying the treatment agent is stored for a long period of time. A treatment agent for degraded acrylic fibers, and an acrylic fiber for carbon fiber production using the treatment agent and a method for producing the carbon fiber using the treatment agent are also provided.

nsted acid)化合物(B)及乙炔系界面活性劑(C)，便可以抑制因胺基所造成的前驅物劣化、以及因乳化劑對纖維內部之浸透所造成的前驅物劣化，遂而完成本申請案的發明。 In order to solve the above-mentioned problems, the inventors of the present invention have conducted intensive studies and found that the deterioration of the precursor produced by applying the treatment agent during long-term storage is attributable to the fact that the amine group-modified polysilicon contained in the treatment agent Oxygen amine group, and the emulsifier used to modify the silicon oxide with the emulsified amine group to penetrate the inside of the fiber. Therefore, it was found that if the amine-modified polysiloxane (A) and Brünster acid (Br

nsted acid) compound (B) and acetylene-based surfactant (C), can inhibit the degradation of precursors caused by amine groups and the degradation of precursors caused by the penetration of emulsifiers into fibers, thus completing the present invention. Invention of the application.

That is, the acrylic fiber treatment agent of the present invention contains an amine group-modified polysiloxane (A), a Brunsted acid compound (B), and an acetylene-based surfactant (C).

The ratio of the Brynster acid compound (B) is preferably 0.01 to 2.5 molar equivalents relative to 1 molar of the amine group of the aforementioned amine group-modified polysiloxane (A).

The ratio of the acetylene-based surfactant (C) is preferably 0.1 to 12 parts by weight relative to 100 parts by weight of the amine group-modified polysiloxane (A).

The aforementioned acetylene-based surfactant (C) is selected from the group consisting of acetylene alcohol (C1), acetylene glycol (C2), a compound (C3) obtained by adding an alkylene oxide to acetylene alcohol, and a compound (C3) obtained by adding an epoxy resin to acetylene glycol. At least one of the compounds (C4) obtained from alkane is preferred.

The aforementioned acetylenic alcohol (C1) is preferably a compound represented by the following general formula (1). The aforementioned acetylene glycol (C2) is preferably a compound represented by the following general formula (2). The compound (C3) obtained by adding an alkylene oxide to the aforementioned acetylene alcohol is preferably a compound represented by the following general formula (3). The compound (C4) obtained by adding an alkylene oxide to the aforementioned acetylene glycol is preferably a compound represented by the following general formula (4).

(式(1)中，R¹及R²分別獨立為碳數1至8之烷基。)

(In formula (1), R ¹ and R ² are each independently an alkyl group having 1 to 8 carbon atoms.)

(式(2)中，R³、R⁴、R⁵及R⁶分別獨立為碳數1至8之烷基。)

(In formula (2), R ³ , R ⁴ , R ⁵ and R ⁶ are each independently an alkyl group having 1 to 8 carbon atoms.)

(式(3)中，R¹及R²分別獨立為碳數1至8之烷基。R⁷為氫原子、或碳數1至5的烷基。AO表示碳數2至4之氧伸烷基。N為1至50的數。)

(In formula (3), R ¹ and R ² are each independently an alkyl group having 1 to 8 carbon atoms. R ⁷ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. AO represents an oxygen extension having 2 to 4 carbon atoms. Alkyl. N is a number from 1 to 50.)

(式(4)中，R³、R⁴、R⁵及R⁶分別獨立為碳數1至8之烷基。R⁷是氫原子、或碳數1至5的烷基。此外，在式(4)中，複數個R⁷可為相同或相異。AO表示碳數2至4的氧伸烷基。m、n分別獨立為1至50之數。)

(In formula (4), R ³ , R ⁴ , R ⁵ and R ⁶ are each independently an alkyl group having 1 to 8 carbon atoms. R ⁷ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. In addition, in the formula In (4), a plurality of R ⁷ may be the same or different. AO represents an oxyalkylene group having 2 to 4 carbon atoms. m and n are each independently a number of 1 to 50.)

The weight ratio of the aforementioned amine group-modified polysiloxane (A) in the nonvolatile matter of the treatment agent is preferably 40 to 95% by weight.

The treatment agent for acrylic fibers of the present invention preferably further contains polyoxyalkylene alkyl ether (D)

The aforementioned polyoxyalkylene alkyl ether (D) preferably contains a compound represented by the following general formula (5).

(通式(5)中，R⁸表示碳數6至22的烷基。AO表示碳數2至4的氧伸烷基。j分別獨立為1至50之數。)

(In the general formula (5), R ⁸ represents an alkyl group having 6 to 22 carbon atoms. AO represents an oxyalkylene group having 2 to 4 carbon atoms. j is each independently a number of 1 to 50.)

With respect to 100 parts by weight of the above-mentioned amino-modified polysiloxane (A), the total ratio of the above-mentioned acetylene-based surfactant (C) and the above-mentioned polyoxyalkylene alkyl ether (D) is 5 to 50 parts by weight. better.

The acrylic fiber for carbon fiber production of the present invention is obtained by adhering the above-mentioned acrylic fiber treatment agent to the raw material acrylic fiber of the acrylic fiber for carbon fiber production.

The method for producing carbon fiber of the present invention includes the following steps: a spinning step of making the above-mentioned fiber treating agent adhere to the raw acrylic fiber of the acrylic fiber for carbon fiber production to perform spinning; converting in an oxidative environment of 200 to 300° C. The flame-resistant treatment step of forming flame-resistant fibers; and the carbonization treatment step of carbonizing the flame-resistant fibers in an inert environment of 300 to 2000° C. again.

The acrylic fiber treatment agent of the present invention can suppress the deterioration of the acrylic fiber for carbon fiber production after storing the acrylic fiber for carbon fiber production produced by applying the treatment agent for a long period of time. When the acrylic fiber for carbon fiber production of the present invention is used, even if the acrylic fiber bundle stored for a long period of time is used, the generation of fluff can be suppressed in the firing step, and high-strength and high-quality carbon fiber can be obtained. According to the method for producing carbon fiber of the present invention, even if acrylic fiber bundles that have been stored for a long time are used, the occurrence of fluff can be suppressed in the firing step, and high-strength and high-quality carbon fibers can be obtained.

(Amino-modified polysiloxane (A))

The treating agent of the present invention must contain amine group-modified polysiloxane (A). The amine group of the modified group of the amine group-modified polysiloxane (containing an organic group with an amine group) can be combined with the side chain of the main chain of the polysiloxane, or with the end, or with both sides, but From the viewpoint of fiber protection in the flame-resistance treatment step, those bonded to a side chain (having an amine group in the side chain) are preferred. In addition, this amine group may be any of a monoamine type, a diamine type, and a polyamine type, or both may be present in one molecule. However, in the flame-resistant treatment step, the treatment agent is uniformly applied to the fiber. It is preferable to use a monoamine type or a diamine type from the viewpoint of film-forming the treatment agent to the inside of the bundle to protect the fibers. The amino group-modified polysiloxane (A) may be used alone or in combination of two or more.

From the viewpoint of exerting the effects of the present application, the dynamic viscosity of the amine group-modified polysiloxane (A) at 25°C is preferably 50 to 30000 mm ² /s. When the dynamic viscosity is less than 50 mm ² /s, the treatment agent tends to scatter, and the solution stability of the emulsion after water-based emulsification deteriorates, and the treatment agent may not be uniformly applied to the fibers. As a result, the adhesion of fibers cannot be prevented. When the dynamic viscosity exceeds 30000mm ² /s, there will be a problem of gum up due to adhesiveness. The upper limit of the dynamic viscosity is preferably 25000 mm ² /s, 20000 mm ² /s, 10000 mm ² /s, 5000 mm ² /s, 4000 mm ² /s, 3000 mm ² /s, 2500 mm ² /s in this order.

The amine group equivalent weight of the amine group-modified polysiloxane (A) is preferably 300 to 10,000 g/mol, more preferably 500 to 10,000 g/mol, and 1000 g/mol, from the viewpoint of preventing adhesion or adhesion between fibers. To 9000 g/mol is still better. When the amine group equivalent is less than 300 g/mol, in the initial stage of the flame-resistant treatment step, the treatment agent may not be uniformly applied to the inside of the fiber bundle due to thermal crosslinking of the treatment agent. In addition, when the amine group equivalent is 10,000 g/mol or more, in the latter stage of the flame-resistant treatment step, the fiber cannot be protected because the treatment agent does not generate thermal crosslinking. Here, the amine group equivalent means the mass of the siloxane skeleton per amine group or ammonium group. The g/mol in the indicated unit is a value converted per 1 mol of the amine group or the ammonium group. Therefore, the smaller the value of the amine group equivalent, the higher the ratio of the amine group or the ammonium group in the molecule.

The amine group-modified polysiloxane (A) may be used in combination with a plurality of amine group-modified polysiloxanes having different amine group equivalents or different dynamic viscosities (25°C). In the case of using two or more kinds of amine group-modified polysiloxane, the above-mentioned amine group equivalent refers to the amine group equivalent of the whole (mixture) of amine group-modified polysiloxane, and the above-mentioned dynamic viscosity at 25°C refers to the amine group equivalent. The meaning of the dynamic viscosity of the base-modified polysiloxane whole (mixture).

As said amino group-modified polysiloxane, the compound represented by following General formula (6) is mentioned, for example.

(式(6)中，R⁹表示碳數1至20的烷基或是芳基。R¹⁰是以下述化學式(7)表示的基。R¹¹是R⁹、R¹⁰或是-OR¹⁷(R¹⁷是氫原子或是碳數為1至6的烷基)。p是10≦p≦10000，q是0.1≦q≦1000。)

(In formula (6), R ⁹ represents an alkyl group having 1 to 20 carbon atoms or an aryl group. R ¹⁰ is a group represented by the following chemical formula (7). R ¹¹ is R ⁹ , R ¹⁰ or -OR ¹⁷ ( R ¹⁷ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms). p is 10≦p≦10000, and q is 0.1≦q≦1000.)

In formula (6), R ⁹ represents an alkyl group having 1 to 20 carbon atoms or an aryl group. R ⁹ is preferably an alkyl group having 1 to 10 carbon atoms or an aryl group, more preferably an alkyl group having 1 to 5 carbon atoms, and still more preferably a methyl group. Moreover, in formula (6), a plurality of R ⁹ may be the same or different. R ¹⁰ is a group represented by the following general formula (7). R ¹¹ is a group represented by R ⁹ , R ¹⁰ or -OR ¹⁷ , preferably R ⁹ . Moreover, in formula (6), a plurality of R ¹¹ may be the same or different.

R ¹⁷ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom or a methyl group. p is a number of 10 to 10000, preferably 50 to 5000, more preferably 100 to 2000. q is a number of 0.1 to 1000, preferably 0.5 to 500, more preferably 1 to 100.

In formula (7), R ¹² and R ¹⁴ each independently represent an alkylene group having 1 to 6 carbon atoms, preferably an alkylene group having 1 to 3 carbon atoms. R ¹³ , R ¹⁵ and R ¹⁶ each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or an aryl group, preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, more preferably a hydrogen atom. r is a number of 0 to 6, preferably 0 to 3, more preferably 0 to 1.

(Brinster acid compound (B))

The fiber treatment agent of the present invention must contain the Brynster acid compound (B). In the case where Brynster acid (B) is not used, even if the acetylene-based surfactant (C), which is an essential component, is used, the time-dependent crosslinking due to the amine group of the amine group-modified polysiloxane cannot be suppressed. The Brunsted acid compound (B) refers to a proton donor, and examples thereof include carboxylic acid compounds, inorganic acids, sulfonic acid compounds, and phosphonic acid compounds. The Brynster acid compound (B) may be used alone or in combination of two or more.

The carboxylic acid compound refers to a compound containing a carboxyl group in its molecular structure. Although it does not specifically limit as a carboxylic acid compound, Aliphatic monocarboxylic acid, aliphatic polyhydric carboxylic acid, aromatic carboxylic acid, aromatic polyhydric carboxylic acid, amino acid etc. are mentioned.

Examples of aliphatic monocarboxylic acids include acetic acid, lactic acid, butyric acid, crotonic acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, capric acid, and lauric acid. acid, myristic acid, myristoleic acid, pentadecanoic acid, palmitic acid, palmitoleic acid, isocetyl acid, margaric acid, hard Fatty acid, isostearic acid, oleic acid, trans-oleic acid, Vaccenic acid, linoleic acid, linolenic acid, arachidic acid, twenty Isoeikosa acid, Gadoleic acid, eicosenoic acid, Behenic acid, Isodocosanoic acid, Erucic acid, Behenic acid, Isotetracosic acid, Nervonic acid, Cerotic acid, Montanic acid, Melissic acid, Polyoxyalkylene monocarboxylic acid acid, polyoxyalkylene alkyl ether monocarboxylic acid, etc.

Examples of aliphatic polyvalent carboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, Monoalkanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, polyoxyalkylene dicarboxylic acid, polyoxyalkylene alkyl ether dicarboxylic acid, and derivatives of these.

Examples of the aromatic monocarboxylic acid include benzoic acid, cinnamic acid, naphthoic acid, toluic acid, and derivatives thereof.

As an aromatic polyvalent carboxylic acid, a phthalic acid, an isophthalic acid, a terephthalic acid, a trimellitic acid, a pyromellitic acid, a derivative|guide_body etc. are mentioned.

Amino acid refers to a compound having both an amino group and a carboxyl group in its molecular structure. Examples include alanine, valine, leucine, isoleucine, phenylalanine, and tryptophan. (tryptophan), methionine (methionine), proline, glycine, tyrosine, serine, threonine, cysteine, asparagine, glutamine ), lysine, arginine, histidine, aspartic acid, glutamic acid, etc.

The inorganic acid refers to an acid containing a non-metal atom as a component. As an inorganic acid, sulfuric acid, nitric acid, phosphoric acid, hydrochloric acid, etc. are mentioned.

Examples of the sulfonic acid compound include: alkylbenzenesulfonic acid, polyoxyalkylene alkyl ether sulfonic acid, higher carbon number fatty acid imidosulfonic acid, alkyl sulfuric acid monoester, polyoxyalkylene sulfuric acid monoester Wait.

As a phosphonic acid compound, an alkylphosphonic acid, an aromatic phosphonic acid, a polyoxyalkylene alkyl ether phosphonic acid, an alkylphosphonic acid alkylphosphoric acid monoester, etc. are mentioned.

The pKa value of the Brynster acid compound (B) ranges from 0 to 7 from the viewpoints of corrosion and safety of equipment, and from the viewpoint of suppressing crosslinking with time due to the amine groups of the amine group-modified polysiloxane. More preferably, it is 1 to 6.5, more preferably 2 to 6.

(Acetylene-based surfactant (C))

The acrylic fiber treatment agent of the present invention must contain an acetylene-based surfactant (C). By combining the amine group-modified polysiloxane with the Brünsted acid compound (B) and the acetylene-based surfactant (C), it is presumed that the amine group of the amine group-modified polysiloxane can inhibit the progressive interaction caused by the amine group. In addition, the penetration of the emulsifier into the interior of the fiber structure during emulsification of the amine-modified polysiloxane aqueous system is suppressed, and as a result, the deterioration of the precursor fiber after the precursor fiber is stored for a long period of time can be suppressed. When other surfactants are used instead of the acetylene-based surfactant (C), even if the Brynster acid compound (B) is used, the penetration of the emulsifier into the interior of the fiber structure cannot be suppressed. The carbon fiber is produced by storing the precursor fiber for a long period of time, and it is presumed that the strength will decrease. In addition, the acetylene-based surfactant refers to a compound having a hydrophilic group such as an acetylene group and a hydroxyl group in its molecular structure. An acetylene type surfactant (C) may be used individually by 1 type, and may be used in combination of 2 or more types.

Acetylene-based surfactant (C) is selected from the group consisting of acetylene alcohol (C1), acetylene glycol (C2), compound (C3) obtained by adding alkylene oxide to acetylene alcohol, and adding alkylene oxide to acetylene glycol. At least one of the obtained compounds (C4) is preferred. Among them, the compound (C3) obtained by adding an alkylene oxide to acetylene alcohol and the compound (C4) obtained by adding an alkylene oxide to acetylene glycol are preferred, and the compound (C4) obtained by adding an alkylene oxide to acetylene glycol is preferred. The obtained compound (C4) is more preferable.

Acetyl alcohol (C1) is a compound which has an ethynyl group and one hydroxyl group in a molecular structure.

The acetylenic alcohol (C1) is preferably a compound represented by the above-mentioned general formula (1).

Acetylene glycol (C2) refers to a compound having an acetylene group and two hydroxyl groups in its molecular structure.

The acetylene glycol (C2) is preferably a compound represented by the above-mentioned general formula (2).

The compound (C3) obtained by adding an alkylene oxide to acetylene alcohol means a compound obtained by adding an alkylene oxide to the hydroxyl group of acetylene alcohol.

The compound (C3) obtained by adding an alkylene oxide to acetylene alcohol is preferably a compound represented by the above-mentioned general formula (3).

A compound (C4) obtained by adding an alkylene oxide to acetylene glycol means a compound obtained by adding at least one hydroxyl group of acetylene glycol to one alkylene oxide.

The compound (C4) obtained by adding an alkylene oxide to acetylene glycol is preferably a compound represented by the above-mentioned general formula (4).

In formula (1) and formula (3), R ¹ and R ² are each independently an alkyl group having 1 to 8 carbon atoms. The alkyl group may be straight chain or branched. The carbon number of the alkyl group is preferably 1 to 7, more preferably 1 to 6, and still more preferably 1 to 5.

In formulae (2) and (4), R ³ , R ⁴ , R ⁵ and R ⁶ are each independently an alkyl group having 1 to 8 carbon atoms. The alkyl group may be straight chain or branched. The carbon number of the alkyl group is preferably 1 to 7, more preferably 1 to 6, and still more preferably 1 to 5.

In formula (3) and formula (4), R ⁷ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. The number of carbon atoms in the alkyl group is preferably 1 to 4, more preferably 1 to 3, and still more preferably 1 to 2.

In formula (3) and formula (4), AO represents an oxyalkylene group having 2 to 4 carbon atoms. That is to say: oxyethylene, oxypropyl or oxybutyl. As the oxyalkylene group, oxyethylidene and oxypropylidene are preferable, and oxyethylene is more preferable. The AO constituting (AO) _n or (AO) _m may be one type or two or more types. In the case of two or more kinds, any of block adducts, alternating adducts, and random adducts may be used.

In formula (3), n is a number from 1 to 50. n is preferably 1-45, more preferably 1-40, still more preferably 1-35.

In formula (4), m and n are each independently a number from 1 to 50. m and n independently are preferably 1 to 45, more preferably 1 to 40, and more preferably 1 to 35.

The HLB (Hydrophilic-Lipophilic Balance) of the acetylene-based surfactant (C) is preferably 4 to 25, more preferably 5 to 20, and 6 To 18 is still better. The HLB in the present invention can be obtained experimentally according to the ATLAS method proposed by Griffin et al.

The acetylene-based surfactant (C) is a known compound and can be easily produced by a known method. For example, such a compound can be obtained by a method of reacting acetylene with a ketone or an aldehyde under pressure in the presence of a catalyst such as a base or a metal compound, which is called the Reppe reaction.

In addition, the above-mentioned compound (C3) or compound (C4) can be prepared by reacting acetylene alcohol (C1) or acetylene glycol (C2) with an alkylene oxide (such as ethylene oxide in the presence of a catalyst such as a base or a metal compound, respectively). alkane and/or propylene oxide) by addition polymerization.

[Acrylic fiber treatment agent]

The treatment agent for acrylic fibers of the present invention contains the above-mentioned amino group-modified polysiloxane (A), a Brunsted acid compound (B), and an acetylene-based surfactant (C).

The weight ratio of the amine group-modified polysiloxane (A) in the nonvolatile matter of the treatment agent is preferably 40 to 95% by weight, more preferably 45 to 94% by weight, and still more preferably 50 to 92% by weight , particularly preferably 55 to 90% by weight. When the weight ratio is less than 40% by weight, the heat resistance of the treatment agent may be insufficient in the flame-resistant treatment step. On the other hand, when the weight ratio exceeds 95% by weight, a stable water-based emulsion may not be obtained after water-based emulsification of the treatment agent.

The weight ratio of the acetylene-based surfactant (C) in the non-volatile matter of the treatment agent is preferably 0.1 to 20% by weight, more preferably 0.2 to 15% by weight, still more preferably 0.3 to 13% by weight, especially It is preferably 0.5 to 10% by weight. When the weight ratio is less than 0.1% by weight, the penetration of the emulsifier into the inside of the fiber structure may not be suppressed. On the other hand, when the weight ratio exceeds 20% by weight, stable handleability may not be obtained.

The ratio of the acetylene-based surfactant (C) to 100 parts by weight of the amine group-modified polysiloxane (A) is 0.1 to 12 from the viewpoint of having both stable handleability and storage stability of the precursor. Parts by weight are preferred. The ratio is preferably 0.2 to 11 parts by weight, more preferably 0.2 to 10 parts by weight, still more preferably 0.5 to 8 parts by weight. When the ratio is less than 0.1 part by weight, the penetration of the emulsifier into the inside of the fiber structure may not be suppressed. On the other hand, when this ratio exceeds 12 parts by weight, stable handleability cannot be obtained.

The ratio of the Brunsted acid compound (B) relative to the ratio of the amine group-modified polysiloxane (A) to the The amine group is 1 molar, preferably 0.01 to 2.5 molar equivalent. The ratio is preferably 0.05 to 2.25 molar equivalents, more preferably 0.1 to 2.0 molar equivalents, and still more preferably 0.12 to 1.5 molar equivalents. When the ratio is less than 0.01 equivalent, there is a case where the time-dependent crosslinking due to the amine group of the amine group-modified polysiloxane cannot be suppressed. On the other hand, when the ratio exceeds 2.5 equivalents, the adhesion in the step may be promoted, and stable workability may not be obtained.

(Polyoxyalkylene alkyl ether (D))

The treating agent of the present invention preferably contains a polyoxyalkylene alkyl ether (D) from the viewpoint of improving emulsifiability. In addition, the polyoxyalkylene alkyl ether refers to a compound having a structure in which an alkylene oxide is added to a saturated aliphatic alcohol, and in the general formula (5), R ⁸ is an alkyl group, and AO is a carbon number A compound in which 2 to 4 oxyalkylene groups, and j is a number of 1 or more. The polyoxyalkylene alkyl ether (D) may be used alone or in combination of two or more.

Examples of polyoxyalkylene alkyl ethers include polyoxyethylhexyl ether, polyoxyethylene heptyl ether, polyoxyethylene octyl ether, polyoxyethylene decyl ether, Polyoxyalkylene straight chain alkanes such as polyoxyethylidene lauryl ether, polyoxyethylene tridecyl ether, polyoxyethylidene tetradecyl ether, polyoxyethylene hexadecyl ether, etc. base ethers; polyoxyalkylene branched primary alkyl ethers such as polyoxyethylene 2-ethylhexyl ether, polyoxyethylene isohexadecyl ether, polyoxyethylene isostearyl ether; Oxyethylene 1-hexylhexyl ether, polyoxyethylene 1-octylhexyl ether, polyoxyethylene 1-hexyl octyl ether, polyoxyethylene 1-pentyl heptyl ether, polyoxyethylene Ethyl 1-heptyl pentyl ether, polyoxyethylidene 1-hexylheptyl ether, polyoxyethylidene 1-heptylhexyl ether, polyoxyethylidene 1-pentyl octyl ether, polyoxyethylene 1-pentyl octyl ether Polyoxyalkylene branched secondary alkyl ethers such as ethyl 1-octanoyl amyl ether, etc.

It is preferable that the polyoxyalkylene alkyl ether (D) must contain the compound represented by the above-mentioned general formula (5) from the viewpoint of exhibiting the effects of the present application. In the general formula (5), R ⁸ is an alkyl group having 6 to 22 carbon atoms. When R ⁸ is a hydrocarbon group other than an alkyl group and the number of carbon atoms in R ⁸ exceeds 22, it will be caused by coking of the polyoxyalkylene alkyl ether in the flame-resistant treatment step, when the precursor is converted into a flame-resistant structure. The disadvantage is that the strength of the carbon fiber may decrease. On the other hand, when the carbon number of R ⁸ is less than 6, the solution stability of the emulsion may be deteriorated after the treatment agent is emulsified in water. The carbon number of R ⁸ is preferably 8 to 20, more preferably 10 to 18, and still more preferably 10 to 16. There may be distribution in the carbon number of R ⁸ , and R ⁸ may be linear or branched.

A represents an alkylene group having 2 to 4 carbon atoms, and AO represents an oxyalkylene group. That is, it represents oxyethylene, oxypropyl or oxybutyl. As the oxyalkylene group, oxyethylidene and oxypropylidene are preferable, and oxyethylene is more preferable. The repeating number j of the oxyalkylene group is a number of 1 to 50, preferably 2 to 40, more preferably 3 to 30. When n exceeds 30, when the above-mentioned amino group-modified polysiloxane is used in combination, in the flame-resistant treatment step, the treatment agent cannot be uniformly applied to the inside of the fiber bundle, and thus sticking occurs. As AO constituting the polyoxyalkylene (AO) _j , one type may be used, or two or more types may be used. In the case of two or more kinds, any of alternate adducts, block adducts, and random adducts may be used. j of AO is the added molar number of the oxyalkylene group.

When the treatment agent contains polyoxyalkylene alkyl ether (D), the weight ratio of the polyoxyalkylene alkyl ether (D) in the nonvolatile matter of the treatment agent is 2 to 25% by weight. Preferably, it is 5 to 20 wt %, more preferably 10 to 20 wt %. When the weight ratio is less than 2% by weight, a stable water-based emulsion may not be obtained after water-based emulsification of the treatment agent. On the other hand, when the weight ratio exceeds 25% by weight, the heat resistance of the treatment agent may be insufficient in the flame-resistant treatment step.

From the viewpoint of improving the long-term storage stability of the precursor, the acetylene-based surfactant (C) and the polyoxyalkylene alkyl ether (D) are added to 100 parts by weight of the amine-modified polysiloxane (A). The total ratio is preferably 5 to 50 parts by weight. When the ratio is less than 5 parts by weight, the emulsion stability is deteriorated. On the other hand, when this weight part exceeds 50 weight part, stable workability|operativity cannot be acquired.

(other surfactants)

The acrylic fiber treatment agent of the present invention may contain surfactants other than the above-mentioned acetylene-based surfactant (C) and polyoxyalkylene alkyl ether (D) within a range that does not inhibit the effects of the present invention. The surfactant is used as an emulsifier, an electric preparation agent, and the like. The surfactant is not particularly limited, and nonionic surfactants, anionic surfactants, cationic surfactants other than the above-mentioned acetylene-based surfactant (C) and polyoxyalkylene alkyl ether (D) can be used. Among the surfactants and amphoteric surfactants, known ones are appropriately selected and used. One type of surfactant may be used, or two or more types may be used in combination.

Examples of nonionic surfactants other than the above-mentioned acetylene-based surfactant (C) and polyoxyalkylene alkyl ether (D) include polyoxyalkylenes such as polyoxyethylene oleyl ether, for example. Alkenyl ethers; polyoxyalkylene alkyl phenyl ethers such as polyoxyethylidene octylphenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene dodecylphenyl ether, etc. ;Polyoxyethylidene tristyryl phenyl ether, polyoxyethylidene styryl phenyl ether, polyoxyethylidene styryl phenyl ether, polyoxyethylidene tritylphenyl ether Ether, polyoxyethylene alkylene benzyl phenyl ether, polyoxyethylene benzyl phenyl ether and other polyoxyalkylene alkyl aryl phenyl ethers; polyoxyethylene monolaurate , Polyoxyethylene monooleate, Polyoxyethylene monostearate, Polyoxyethylene monomyristate, Polyoxyethylene dilaurate, Polyoxyethylene dioleate Polyoxyalkylene fatty acid esters such as acid esters, polyoxyethylidene dimyristate, polyoxyethylidene distearate, etc.; sorbitan monopalmitate, sorbitan monooleic acid sorbitan esters such as esters; polyoxyalkylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monostearate and polyoxyethylidene sorbitan monooleate; Glycerol fatty acid esters such as glycerol monostearate, glycerol monolaurate, and glycerol monopalmitate; polyoxyalkylene sorbitan fatty acid esters; sucrose fatty acid esters; polyoxyethylene castor oil ether, etc. Polyoxyalkylene castor oil ether; polyoxyalkylene hydrogenated castor oil ether and other polyoxyalkylene hydrogenated castor oil ether; oxyethylene-oxypropylene block or random copolymer; oxyethylene - an oxypropylene block or terminal sucrose etherate of a random copolymer; etc. The weight average molecular weight of the nonionic surfactant is preferably below 2000, more preferably from 200 to 1800, still more preferably from 300 to 1500, and most preferably from 500 to 1000.

Examples of anionic surfactants include fatty acid salts such as sodium oleate, potassium palmitate, and triethanolammonium oleate; carboxylates containing hydroxyl groups such as potassium glycolate and potassium lactate; Polyoxyalkylene alkyl ether acetates such as ethylidene tridecyl ether acetate sodium salt; salts of carboxyl polysubstituted aromatic compounds such as potassium trimellitate and potassium pyromellitic acid; dodecylbenzenesulfonate Alkylbenzene sulfonates such as sodium salts; polyoxyalkylene alkyl ether sulfonates such as potassium polyoxyethylene 2-ethylhexyl ether sulfonate; sodium stearylmethyl taurate, N -Acidyl sarcosinate; alkyl phosphonates such as octylphosphonate potassium salt; aromatic phosphonates such as phenylphosphonate potassium salt; 2-ethylhexylphosphonate mono-2-ethylhexyl Alkyl phosphonic acid alkyl phosphate salts such as ester potassium salts; nitrogen-containing alkyl phosphonates such as aminoethylphosphonic acid diethanolammonium salts; 2-ethylhexyl sulfate sodium salts and other alkyl sulfate ester salts; polyoxy Ethylene 2-ethylhexyl ether sulfate sodium salt and other polyoxyalkylene sulfate salts; di-2-ethylhexyl sulfosuccinate sodium, dioctyl sulfosuccinate sodium, etc. Chain sulfosuccinate, monosodium N-lauryl glutamate, disodium N-stearyl-L-glutamate, etc. long chain N-acyl glutamate salt etc.

Examples of cationic surfactants include lauryl trimethyl ammonium chloride, tetradecyl trimethyl ammonium chloride, palmityl trimethyl ammonium chloride, and stearyl trimethyl ammonium chloride. , Oleyl Trimethyl Ammonium Chloride, Cetyl Trimethyl Ammonium Chloride, Behenyl Trimethyl Ammonium Chloride, Coconut Oil Alkyl Trimethyl Ammonium Chloride, Tallow Alkyl Trimethyl Ammonium Chloride Methyl Ammonium Chloride, Stearyl Trimethyl Ammonium Bromide, Cocoacyl Trimethyl Ammonium Bromide, Cetyl Trimethyl Ammonium Methyl Sulfate, Oleyl Dimethyl Ethyl Ethyl Ammonium sulfate, dioctyl dimethyl ammonium chloride, dilauryl dimethyl ammonium chloride, distearyl dimethyl ammonium chloride, octadecyl diethyl ammonium methyl sulfate and other alkyl quaternary Ammonium salt; (polyoxyethylidene) lauryl amino ether lactate, stearyl amino ether lactate, bis (polyoxyethylidene) lauryl methyl amino ether dimethyl phosphate, bis (polyoxyethylidene) lauryl amino ether dimethyl phosphate Polyoxyethylidene) Laurylethylammonium Ethosulfate, Di(polyoxyethylidene) Hardened Tallow Alkylethylamine Ethosulfate, Di(polyoxyethylene)laurylmethylammonium Di Methyl phosphate, bis(polyoxyethylidene)stearylamine lactate and other (polyoxyalkylene)alkylamine ether salts; N-(2-hydroxyethyl)-N,N-dimethyl N-stearyl amidopropyl ammonium nitrate, lanolin fatty acid amidopropyl ethyl dimethyl ammonium ethyl sulfate, lauryl amido ethyl methyl diethyl ammonium methyl sulfate Salts and other acylamide alkyl quaternary ammonium salts; Dipalmityl polyethenoxy ethyl ammonium chloride, distearyl polyethenoxy methyl ammonium chloride and other alkyl ethylenes Oxygen quaternary ammonium salt; alkyl isoquinolinium salts such as lauryl isoquinolinium chloride; alkanes such as lauryl dimethyl benzyl ammonium chloride, stearyl dimethyl benzyl ammonium chloride benzalkonium salt; benzalkonium {2-[2-(p-1,1,3,3-tetramethylbutylphenoxy)ethoxy] Benzethonium salts such as ethyl}ammonium chloride; pyridinium salts such as hexadecylpyridinium chloride; oleyl hydroxyethyl imidazolium ethyl sulfate, lauryl hydroxyethyl imidazolium ethyl Imidazolium salts such as sulfates; N-cocoyl arginine ethyl ester pyrrolidone carboxylic Acid Salt, N-laurylysine ethyl ethyl ester chloride Alkyl basic amino acid alkyl ester salts such as compounds; primary ammonium salts such as laurylamine chloride, stearylamine bromide, hardened tallow alkylamine chloride, rosinamine acetate; cetylmethyl Amine sulfate, laurylmethylamine chloride, dilaurylamine acetate, stearylethylamine bromide, laurylpropylamine acetate, dioctylamine chloride, octadecylethylamine Secondary ammonium salts such as hydroxide; dilaurylmethylamine sulfate, lauryldiethylamine chloride, laurylethylmethylamine bromide, dilaurylmethylamine Tertiary ammonium salts such as ethanolstearylamide ethylamine trihydroxyethyl phosphate, stearylamide ethyl ethanolamine urea polycondensate acetate; fatty acid amide ureonium salt; lauryl triethylene glycol hydrogen Alkyl trialkanediol ammonium salts such as ammonium oxide, etc.

As an amphoteric surfactant, for example, sodium 2-undecyl-N,N-(hydroxyethylcarboxymethyl)-2-imidazoline, 2-cocoyl-2-imidazolium hydrogen Oxide-1-carboxyethoxy 2 sodium salt and other imidazoline amphoteric surfactants; 2-heptadecyl-N-carboxymethyl-N-hydroxyethyl imidazolium betaine, lauryl dimethyl Aminoacetic acid betaine, alkyl betaine, amide betaine, sulfobetaine and other betaine amphoteric surfactants; N-laurylglycine, N-lauryl β-alanine, N- Amino acid type amphoteric surfactants such as stearyl β-alanine, etc.

(other ingredients)

The acrylic fiber treatment agent of the present invention may contain other components than the above-mentioned components within the range that does not inhibit the effects of the present invention. Examples of other components include antioxidants such as acidic phosphoric acid esters, phenolic, amine, sulfur, phosphorus, and quinone-based antioxidants; sulfate ester salts, sulfonates, and sulfonates of higher alcohols or higher alcohol ethers. Phosphate esters of high carbon number alcohols/high carbon number alcohol ethers, quaternary ammonium salt type cationic surfactants, ammonium salt type cationic surfactants and other antistatic agents; alkyl esters of high carbon number alcohols, high carbon number alcohols Alcohol ethers, waxes and other smoothing agents; antibacterial agents; preservatives; rust inhibitors; and hygroscopic agents, etc.

Moreover, the processing agent of this invention may contain the modified polysiloxane other than the above-mentioned amino group-modified polysiloxane in the range which does not inhibit the effect of this invention. Examples of modified polysiloxanes include: amine-based polyether-modified polysiloxane, amide-modified polysiloxane, amide-polyether-modified polysiloxane, epoxy-based modified polysiloxane, polysiloxane Ether-modified polysiloxane, epoxy-based polyether-modified polysiloxane (for example, refer to Japanese Patent No. 4616934), methanol-modified polysiloxane, alkyl-modified polysiloxane, phenol-modified polysiloxane, methyl alcohol Acrylate-modified polysiloxane, alkoxy-modified polysiloxane, fluorine-modified polysiloxane, etc., and one type of modified polysiloxane can be used, or a plurality of modified polysiloxanes can be used in combination.

In the acrylic fiber treatment agent of the present invention, amine group-modified polysiloxane (A), Brynster acid compound (B), acetylene-based surfactant (C), and optionally polyoxyalkylene alkyl ether (D) is preferably dissolved, solubilized, emulsified or dispersed in water.

There are no particular limitations on the weight ratio of water and the weight ratio of non-volatile matter occupied in the entire acrylic fiber treatment agent. For example, it may be appropriately determined in consideration of the conveyance cost when conveying the acrylic fiber treating agent of the present invention, the handleability due to the viscosity of the emulsion, and the like. The weight ratio of water in the entire acrylic fiber treating agent is preferably 0.1 to 99.9% by weight, more preferably 10 to 99.5% by weight, and particularly preferably 50 to 99% by weight. The weight ratio (concentration) of the nonvolatile matter in the entire acrylic fiber treatment agent is preferably 0.01 to 99.9% by weight, more preferably 0.5 to 90% by weight, and particularly preferably 1 to 50% by weight.

The acrylic fiber processing agent of this invention can be manufactured by mixing the components demonstrated above. The method for emulsifying and dispersing the components described above is not particularly limited, and a known method can be employed. As such a method, for example, a method of throwing the components constituting the acrylic fiber treatment agent into warm water with stirring to emulsify and disperse them, or mixing the components constituting the acrylic fiber treatment agent and using a homogenizer can be used. , Homogenizer, ball mill, etc., continue to apply mechanical shearing force, and at the same time slowly add water to make it phase inversion emulsification method, etc.

The acrylic fiber treatment agent of the present invention can be suitably used as a treatment agent (precursor treatment agent) for acrylic fibers (precursor) for carbon fiber production. It can also be used as a spinning finish for acrylic fibers other than precursors.

From the viewpoint of imparting good fiber bundle bundle properties in the spinning step or flame resistance step of the precursor, the viscosity of the nonvolatile content of the acrylic fiber treating agent of the present invention at 25°C is 10 to 50000 mPa‧ s is preferably, and when the viscosity is less than 10 mPa·s, the bundled properties of the fiber bundles may be deteriorated in the precursor spinning step or the flame resistance step. In addition, when the viscosity exceeds 50,000 mPa·s, the viscosity of the treatment agent may become too high even if good fiber bundle bundling properties are provided in the precursor spinning step or the flame resistance step, thereby deteriorating the handleability of the treatment agent. situation. The viscosity is preferably 10 to 25000 mPa·s, 10 to 15000 mPa·s, 10 to 10000 mPa·s, 10 to 5000 mPa·s, and 50 to 1000 mPa·s in this order.

[Acrylic fiber for carbon fiber production, its production method, and carbon fiber production method]

The acrylic fiber (precursor) for carbon fiber production of the present invention is obtained by attaching the above-mentioned acrylic fiber treatment agent to the raw acrylic fiber of the precursor and spinning. The method for producing a precursor of the present invention includes a spinning step of making the above-mentioned acrylic fiber treatment agent adhere to the raw acrylic fiber of the precursor and spinning.

The carbon fiber manufacturing method of the present invention comprises the following steps: a spinning step of making the precursor acrylic fiber adhere to the raw material acrylic fiber of the precursor, and spinning the precursor; The flame-resistant treatment step of converting the precursor of the flame-resistant fiber into flame-resistant fiber in an oxidizing environment of 200 to 300 ° C; and carbonization treatment of carbonizing the flame-resistant fiber again in an inert environment of 300 to 2000 ° C. step.

According to the method for producing carbon fiber of the present invention, since the acrylic fiber treating agent of the present invention is used, the treating agent can be uniformly applied to the inside of the fiber bundle in the initial stage of the flame-resistant treatment step, and the flame-resistant treatment can be performed. In the latter stage of the process, the treatment agent is formed into a film to protect the fibers, so that the adhesion between fibers and the occurrence of fluff can be suppressed, and high-quality carbon fibers can be produced.

The spinning step is a step of attaching the acrylic fiber treatment agent to the raw material acrylic fiber of the precursor to spin the precursor, and includes an adhesion treatment step and an elongation step.

The adhesion treatment step is a step of attaching the acrylic fiber treatment agent after spinning the raw material acrylic fiber of the precursor. That is, in the adhesion treatment step, the acrylic fiber treatment agent is adhered to the raw material acrylic fiber of the precursor. In addition, although the raw acrylic fiber of this precursor is stretched immediately after spinning, the high-rate stretching after the adhesion treatment step is particularly referred to as a "stretching step". The stretching step may be a wet heat stretching method using high-temperature steam, or a dry heat stretching method using a hot roller.

The precursor is composed of acrylic fibers whose main component is polyacrylonitrile, and the polyacrylonitrile is obtained by copolymerizing at least 95 mol% or more of acrylonitrile and 5 mol% or less of a flame resistance promoting component. As the flame resistance promoting component, a vinyl group-containing compound having copolymerizability with respect to acrylonitrile is suitably used. The single fiber fineness of the precursor is not particularly limited, but is preferably 0.1 to 2.0 dTex from the viewpoint of the balance between performance and production cost. In addition, the count of the number of single fibers constituting the fiber bundle of the precursor is not particularly limited, but is preferably 1,000 to 96,000 from the viewpoint of the balance between performance and production cost.

Although the acrylic fiber treating agent can be attached to the raw material acrylic fiber of the precursor at any stage of the spinning step, it is preferably attached before the stretching step. If it is a stage before the stretching step, it can be attached at any stage, for example, immediately after spinning. In addition, it may be reattached at any stage after the stretching step, for example, it may be reattached immediately after the stretching step, may be reattached in the coiling step, or may be reattached before the flame resistance treatment step. As for the adhesion method, it may be adhered using a roller or the like, or may be adhered by a dipping method, a spray method, or the like.

In terms of the balance between obtaining the effect of preventing fiber-fiber adhesion or preventing adhesion, and preventing the quality degradation of carbon fibers caused by the coking of the treatment agent in the carbonization treatment step, in the adhesion treatment step, relative to the weight of the precursor , the application rate of the acrylic fiber treatment agent is preferably 0.1 to 2% by weight, more preferably 0.3 to 1.5% by weight. If the application rate of the acrylic fiber treatment agent is less than 0.1% by weight, the adhesion between the single fibers cannot be sufficiently prevented, and then the strength of the obtained carbon fiber decreases. On the other hand, if the application rate of the acrylic fiber treatment agent exceeds 2% by weight, the acrylic fiber treatment agent will excessively cover between the single fibers, preventing the oxygen supply to the fibers in the flame-resistant treatment step, and the strength of the obtained carbon fiber will be reduced. reduce. In addition, the application rate of the acrylic fiber treatment agent referred to here is defined as the percentage of the weight of the non-volatile content to which the acrylic fiber treatment agent adheres with respect to the weight of the precursor.

The flame-resistant treatment step is a step of converting the precursor attached with the acrylic fiber treatment agent into flame-resistant fibers in an oxidative environment at 200 to 300°C. The oxidizing surrounding gas generally only needs to be an air environment. The temperature of the oxidizing surrounding gas is preferably 230 to 280°C. In the flame-resistant treatment step, a tension of 0.90 to 1.10 (preferably 0.95 to 1.05) in elongation ratio is applied with respect to the acrylic fiber after the adhesion treatment, while heat treatment is performed for 20 to 100 minutes (preferably 30 to 60 minutes) ). In this flame-resistant treatment, a flame-resistant fiber having a flame-resistant structure is produced through intramolecular cyclization and cycloaddition of oxygen.

The carbonization treatment step is a step of further carbonizing the flame-resistant fiber in an inert atmosphere at 300 to 2000°C. In the carbonization treatment step, it is preferable to first apply a tension of 0.95 to 1.15 to the flame-resistant fibers in a firing furnace with a temperature gradient of 300°C to 800°C in an inert ambient gas such as nitrogen and argon. The heat treatment is simultaneously performed for several minutes to perform the preliminary carbonization treatment step (first carbonization treatment step). After that, in order to further carbonize and perform graphitization, in an inert atmosphere such as nitrogen and argon, a tension of a stretching ratio of 0.95 to 1.05 is applied to the first carbonization treatment step, and heat treatment is performed for several minutes at the same time, so as to perform a second carbonization treatment step. The carbonization treatment step carbonizes the flame-resistant fibers. In the control of the heat treatment temperature in the second carbonization treatment step, a temperature gradient can be applied while setting the maximum temperature to 1000°C or higher (preferably 1000 to 2000°C). The maximum temperature can be appropriately selected and determined according to the required properties (tensile strength, elastic modulus, etc.) of the desired carbon fiber.

In the method for producing a carbon fiber of the present invention, if a carbon fiber having a higher elastic modulus is desired, the graphitization treatment step may be performed subsequent to the carbonization treatment step. The graphitization treatment step is usually performed at a temperature of 2000 to 3000° C. while applying tension to the fibers obtained in the carbonization treatment step in an inert atmosphere such as nitrogen and argon.

In the carbon fiber thus obtained, the surface treatment can be carried out according to the purpose to improve the bonding strength with the matrix resin when used as a composite material. As a method of surface treatment, gas phase or liquid phase treatment can be employed, but from the viewpoint of productivity, liquid phase treatment with an electrolytic solution such as acid or alkali is preferable. In addition, in order to improve the processability and handleability of carbon fibers, various sizing agents excellent in compatibility can be added to the matrix resin.

(Example)

Hereinafter, although the present invention will be specifically described by way of examples, the present invention is not limited to the examples described herein. In addition, the percentages (%) and parts shown in the following examples represent "% by weight" and "parts by weight" unless otherwise specified. The measurement of each characteristic value was performed according to the method shown below.

<Dosing rate of treatment agent>

After the precursor after the application of the treatment agent was subjected to alkali fusion with potassium hydroxide/sodium butyrate, it was dissolved in water and adjusted to pH 1 with hydrochloric acid. After adding sodium sulfite and ammonium molybdate to develop color, the colorimetric quantification of silicon molybdenum blue (wavelength 815mμ) was performed to obtain the content of silicon. The application rate (% by weight) of the acrylic fiber treatment agent was calculated using the silicon content obtained here and the value of the silicon content in the treatment agent obtained by the same method in advance.

<Adhesion resistance>

20 points were arbitrarily selected from the carbon fibers, short fibers having a length of 10 mm were cut out, and the bonding state thereof was observed and judged according to the following evaluation criteria.

◎: No connection

○: Almost no follow-up

△: The following is less

×: more after

<Strand Hardness of Precursor>

The hardness of the precursor strands (length: about 50 cm) was measured with a texture tester (HANDLE-O-METHRHOM-2, manufactured by Taiei Science Precision Instrument Co., Ltd., with a slit width of 5 mm). In addition, the measurement was performed 10 times, and the smaller the average value, the softer the precursor strand was judged to be. At the time of evaluation, the precursor immediately after production (within 7 days after production) and the precursor after storage at room temperature for 12 months after production (after storage is indicated in the table) were used.

<Wipe resistance>

Using a TM-type friction coupling force testing machine TM-200 (manufactured by Taiei Scientific Seiki Co., Ltd.), the precursor strands (12K) were wiped 1000 times with a tension of 50g through three mirror-plated stainless steel needles arranged in a zigzag shape (reciprocating motion). speed of 300 times/min), and the fluffing state of the precursor strand was visually judged according to the following criteria. At the time of evaluation, the precursor immediately after production (within 7 days after production) and the precursor after being stored at room temperature for 12 months after production were used.

◎: No fluff is seen at all as before wiping

○: Several fluffs are seen, but the scratch resistance is good

△: The fuzz is slightly generated and the scratch resistance is slightly inferior

×: There is a lot of fluff, and the filament is obviously cut off, and the rubbing resistance is poor.

<Carbon Fiber Strength>

It was measured according to the epoxy resin-impregnated strand method specified in JIS-R-7601, and the average value of 10 times of measurement was taken as the carbon fiber strength (GPa). At the time of evaluation, the precursor immediately after production (within 7 days after production) and the precursor produced at room temperature and stored for 12 months were used.

[Example 1]

Aqueous emulsification was performed by mixing amine group modified polysiloxane A1, Brynster acid compound B1, polyoxyethylidene alkyl ether D1 and water so as to have the nonvolatile composition of the treatment agent shown in Table 1. , Add acetylene-based surfactant C1 to the obtained amino-modified polysiloxane water-based emulsion, and prepare the non-volatile matter of the treatment agent so that the weight ratio of amino-modified polysiloxane A1 accounts for 80% by weight, and the The weight ratio of steric acid compound B1 is 0.7% by weight, the weight ratio of acetylene-based surfactant C1 is 2% by weight, and the weight ratio of polyoxyethylene alkyl ether D1 is 17.3% by weight. Treatment agent (precursor treatment agent) agent). In addition, the non-volatile matter concentration of the treatment agent was set to 20% by weight.

Next, the adjusted treatment agent was further diluted with water to obtain a treatment liquid having a nonvolatile concentration of 3.0% by weight.

The treatment liquid was adhered to the raw acrylic fiber obtained by copolymerizing 97 mol% of acrylonitrile and 3 mol% of itonic acid to obtain a precursor so that the application rate was 1.0%, and passed through an elongation step (steam elongation). , the stretching ratio was 2.1 times) to prepare a precursor (single fiber fineness 0.8 dTex, 24,000 filamentous fibers). The precursor was converted into carbon fibers by being flame-resistant in a flame-resistant furnace at 250°C for 60 minutes, followed by firing in a carbonization furnace with a temperature gradient of 300 to 1400°C under nitrogen ambient gas. Table 1 shows the evaluation results of the respective characteristic values.

[Examples 2 to 22, Comparative Examples 1 to 17]

In Example 1, the same procedure as in Example 1 was carried out, except that the treatment liquid was adjusted so as to have the nonvolatile composition of the treatment agent shown in Tables 2 to 4 to obtain a treatment agent after adhesion. Precursors and carbon fiber. The evaluation results of the respective characteristic values are shown in Tables 1 to 4.

In addition, the detailed non-volatile matter composition of Tables 1 to 4 is as follows.

<Amino-modified polysiloxane (A)>

Amine modified polysiloxane A1 (viscosity at 25°C: 250mm ² /s, amine equivalent weight: 7600g/mol, diamine type)

Amine modified polysiloxane A2 (viscosity at 25℃: 1300mm ² /s, amine equivalent weight: 1700g/mol, diamine type)

Amine modified polysiloxane A3 (viscosity at 25°C: 1700mm ² /s, amine equivalent weight: 3800g/mol, monoamine type)

Amine modified polysiloxane A4 (viscosity at 25℃: 20000mm ² /s, amine equivalent weight: 1800g/mol, diamine type)

Amine modified polysiloxane A5 (viscosity at 25℃: 1500mm ² /s, amine equivalent weight: 3800g/mol, diamine type)

<Brinster acid compound (B)>

Carboxylic acid compound B1: acetic acid

Carboxylic acid compound B2: Benzoic acid

Carboxylic acid compound B3: arginine

Carboxylic acid compound B4: phosphoric acid

<Acetylene-based Surfactant (C)>

Acetylene-based surfactant C1: 20-molar adduct of ethylene oxide of 2,4,7,9-tetramethyl-5-decyne-4,7-diol (in formula (4), R ³ , R ⁵ are all methyl groups, R ⁴ and R ⁶ are all isobutyl groups, R ⁷ is a hydrogen atom, AO is ethylene oxide, n+m=20.)

Acetylene-based surfactant C2: 5-molar adduct of ethylene oxide of 2,4,7,9-tetramethyl-5-decyne-4,7-diol (in formula (4), R ³ , R ⁵ are methyl groups, R ⁴ and R ⁶ are isobutyl groups, R ⁷ is hydrogen atom, AO is ethylene oxide, n+m=5.)

Acetylene-based surfactant C3: 3,6-dimethyl-4-octyne-3,6-diol (in formula (2), R ³ and R ⁵ are both methyl groups, and R ⁴ and R ⁶ are both ethyl, R ⁷ is a hydrogen atom.)

Acetylene-based surfactant C4: 2,4,7,9-tetramethyl-5-decyne-4,7-diol (in formula (2), R ³ and R ⁵ are both methyl groups, and R ⁴ , R ⁶ are all isobutyl groups, and R ⁷ are hydrogen atoms.)

<Polyoxyalkylene alkyl ether (D)>

Polyoxyethylene alkyl ether D1: alkyl ether with 12 to 14 carbon atoms added with 5 moles of oxyethylene

Polyoxyethylene alkyl ether D2: alkyl ether with 12 to 14 carbon atoms to which 7 moles of oxyethylene is added

Polyoxyethylene alkyl ether D3: alkyl ether with 12 to 14 carbon atoms to which 9 moles of oxyethylene is added

In addition, in Tables 1 to 4, the values in the parentheses of the Brünsted acid compound (B) represent the Brünsted acid compound ( B) molar equivalents. In addition, the numerical value in the parenthesis of the acetylene-based surfactant (C) represents the weight ratio of the acetylene-based surfactant (C) when the amine group-modified polysiloxane (A) is taken as 100 parts by weight. In addition, the numerical values written in parentheses after storage of strand hardness and carbon fiber strength represent the rate of change with respect to the numerical values immediately after manufacture.

As can be understood from Tables 1 to 4, compared with the acrylic fiber treatment agent phase of the comparative example without the Brynster acid compound (B) and/or the acetylene-based surfactant (C), the acrylic fiber treatment agent of the Example It is excellent in suppressing the deterioration over time of the acrylic fiber for carbon fiber production.

[Industrial availability]

The acrylic fiber treatment agent of the present invention is a treatment agent used when producing acrylic fibers for carbon fiber production, and can be used to produce high-level carbon fibers. The acrylic fiber for carbon fiber production of the present invention is treated with the treatment agent of the present invention, and can be used to produce high-level carbon fibers. High-level carbon fibers can be obtained by the method for producing carbon fibers of the present invention.

Claims (11)

A treatment agent for acrylic fibers, which contains amine-modified polysiloxane (A), a Brunsted acid compound (B) and an acetylene-based surfactant (C). The treating agent for acrylic fibers according to claim 1, wherein the ratio of the Brünsted acid compound (B) to 1 mole of the amine group of the aforementioned amine group-modified polysiloxane (A) is 0.01 to 2.5 molar equivalents. The treating agent for acrylic fibers according to claim 1 or 2, wherein the ratio of the acetylene-based surfactant (C) to 100 parts by weight of the amine group-modified polysiloxane (A) is 0.1 to 12 parts by weight. The treatment agent for acrylic fibers according to claim 1 or 2, wherein the acetylene-based surfactant (C) is selected from the group consisting of acetylene alcohol (C1), acetylene glycol (C2), acetylene alcohol addition At least one of a compound (C3) obtained by adding an alkylene oxide and a compound (C4) obtained by adding an alkylene oxide to acetylene glycol. The treating agent for acrylic fibers according to claim 4, wherein the acetylene alcohol (C1) is a compound represented by the following general formula (1), and the acetylene glycol (C2) is a compound represented by the following general formula ( The compound represented by 2) is a compound obtained by adding an alkylene oxide to the aforementioned acetylene alcohol (C3) is a compound represented by the following general formula (3), a compound obtained by adding an alkylene oxide to the aforementioned acetylene glycol (C4) is a compound represented by the following general formula (4);

In formula (1), R ¹ and R ² independently represent an alkyl group having 1 to 8 carbon atoms;

In formula (2), R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent an alkyl group having 1 to 8 carbon atoms;

In formula (3), R ¹ and R ² each independently represent an alkyl group having 1 to 8 carbon atoms; R ⁷ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; AO represents an oxyalkylene having 2 to 4 carbon atoms base, n is a number from 1 to 50;

In formula (4), R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent an alkyl group having 1 to 8 carbon atoms, and R ⁷ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; in addition, in formula ( In 4), a plurality of R ⁷ may be the same or different, AO represents an oxyalkylene group having 2 to 4 carbon atoms; m and n each independently represent a number of 1 to 50. The treatment agent for acrylic fibers according to claim 1 or 2, wherein the weight ratio of the amine group-modified polysiloxane (A) in the non-volatile matter of the treatment agent is 40 to 95 by weight %. The treating agent for acrylic fibers as described in claim 1 or 2 of the claimed scope further contains polyoxyalkylene alkyl ether (D). The treatment agent for acrylic fibers as described in claim 7, wherein the polyoxyalkylene alkyl ether (D) contains a compound represented by the following general formula (5);

In the general formula (5), R ⁸ represents an alkyl group having 6 to 22 carbon atoms; AO represents an oxyalkylene group having 2 to 4 carbon atoms; and j each independently represents a number of 1 to 50. The treatment agent for acrylic fibers according to claim 7, wherein, with respect to 100 parts by weight of the amine group-modified polysiloxane (A), the acetylene-based surfactant (C) and the polyoxyethylene The total ratio of the base alkyl ether (D) is 5 to 50 parts by weight. An acrylic fiber for carbon fiber production is obtained by adhering the acrylic fiber treatment agent described in any one of claims 1 to 9 of the application scope to a raw material acrylic fiber of the acrylic fiber for carbon fiber production. A method for producing carbon fiber, comprising the following steps: a spinning step of making the acrylic fiber treatment agent described in any one of the claims 1 to 9 attached to the raw material acrylic fiber of the acrylic fiber for carbon fiber production and spinning; A flame-resistant treatment step of converting into flame-resistant fibers in an oxidizing environment of 200 to 300°C; and a carbonization treatment step of carbonizing the flame-resistant fibers again in an inert environment of 300 to 2000°C.