JP7021071B2 - Acrylic fiber treatment agent and its uses - Google Patents

Description

The present invention relates to an acrylic fiber treatment agent and its use. More specifically, a treatment agent used for producing acrylic fiber, an acrylic fiber for carbon fiber production using the treatment agent (hereinafter, may be referred to as precursor), and a carbon fiber using the treatment agent. Regarding the manufacturing method.

Utilizing its excellent mechanical properties, carbon fiber is widely used as a reinforcing fiber for a composite material with a plastic called a matrix resin, for aerospace applications, sports applications, general industrial applications, and the like.
As a method for producing carbon fiber, a precursor is first produced (the manufacturing process of this precursor may be referred to as a yarn-making process). This precursor is converted into flame-resistant fibers in an oxidizing atmosphere at 200 to 300 ° C. (this step may be hereinafter referred to as a flame-resistant treatment step), and then carbonized in an inert atmosphere at 300 to 2000 ° C. (Hereinafter, this step may be referred to as a carbonization treatment step) is common (hereinafter, the flame resistance treatment step and the carbonization treatment step may be collectively referred to as a firing step). The precursor is manufactured through a stretching step in which it is stretched at a higher magnification than that of ordinary acrylic fiber. At that time, the fibers are liable to stick to each other, and high-magnification stretching is not performed uniformly, resulting in a non-uniform precursor. The carbon fiber obtained by firing such a precursor has a problem that sufficient strength cannot be obtained. Further, when the precursor is fired, there is a problem that the single fibers are fused with each other and the quality and quality of the obtained carbon fibers are deteriorated.

As a treatment agent to be applied to the precursor for preventing the sticking of the precursor and the fusion of carbon fibers, a silicone-based treatment agent having low fiber-fiber friction under wet conditions and in a high temperature environment and having excellent peelability, in particular. Many techniques for imparting an amino-modified silicone-based treatment agent capable of further improving heat resistance by a cross-linking reaction by heat to a precursor have been proposed (see Patent Documents 1 and 2).
A commonly used amino-modified silicone-based treatment agent is an aqueous emulsion of an amino-modified silicone oil. If it is not a self-emulsifying amino-modified silicone, an aqueous emulsion is carried out using a surfactant. In order to apply this aqueous emulsion to the precursor fiber, it is necessary to remove water after the application, and it is necessary to pass through a drying step. After that, thermal stretching is further performed in the stretching step. When a cross-linking reaction of an amino-modified silicone-based treatment agent having good thermal cross-linking property occurs on the fibers in these heat treatment steps and a film is formed, the treatment agent cannot move inside the fiber bundle in the flame resistance treatment step, so that the single fibers are fused together. Is likely to occur, and the problem that the strength of the carbon fiber is lowered is likely to occur. Further, in order to suppress the thermal crosslinkability of the amino-modified silicone, a technique of adding an antioxidant to the amino-modified silicone-based treatment agent has been proposed (see Patent Documents 3 to 4). However, when the antioxidant is added to the amino-modified silicone-based treatment agent, the cross-linking reaction of the amino-modified silicone in the heat treatment step is suppressed, but the cross-linking reaction of the treatment agent is unlikely to occur even in the flame-resistant treatment step, and the film of the treatment agent is formed. Since the fiber protection property is lowered due to the conversion, fluff is generated, and the problem that the strength of the carbon fiber is lowered is likely to occur.

Japanese Patent Application Laid-Open No. 2001-172879 Japanese Patent Application Laid-Open No. 2002-129481 Japanese Patent Application Laid-Open No. 2-91224 Japanese Patent Application Laid-Open No. 11-012853

In view of the prior art background, an object of the present invention is an acrylic fiber treatment agent capable of suppressing fusion between fibers and generation of fluff in a flame resistant treatment step and further obtaining stable operability. It is an object of the present invention to provide an acrylic fiber for producing carbon fiber using a treatment agent and a method for producing carbon fiber using the treatment agent.

As a result of diligent studies to solve the above problems, the present inventors have 1) uniformly applied the treatment agent to the inside of the fiber bundle at the initial stage of the flame resistance treatment step, and 2) at the latter stage of the flame resistance treatment step. I thought that if the treatment agent could be formed into a film to protect the fibers, fusion between the fibers and the generation of fluff could be suppressed, and high-quality carbon fibers could be produced. 3) Then, if the ratio P (t) of the film component and the liquid component when the non-volatile component of the treatment agent is treated under specific heat treatment conditions is within a specific range, the actions of 1) and 2) above. As a result, it was found that the problem of the present application could be solved, and the present invention was reached.

That is, the treatment agent for acrylic fibers of the present invention contains an amino-modified silicone and a polyoxyalkylene alkyl ether, and the ratio P (10) defined by the following formula (A) is in the range of 0.01 to 0.5. Yes, the ratio P (30) defined by the following formula (A) is in the range of 0.01 to 1.5, and the ratio P (120) defined by the following formula (A) is 2.0 to 10. It is a range.
P (t) = W2 (t) / (W1 (t) -W2 (t)) (A)
W1 (t): Weight (g) of the residue when the non-volatile content of the acrylic fiber treatment agent is heat-treated at 250 ° C. for t minutes.
W2 (t): The weight (g) of the residue after immersing the residue W1 (t) in chloroform to dissolve the soluble component and removing the chloroform-dissolving component by filtration.

The amino-modified silicone is preferably an amino-modified silicone having an amino group in the side chain.
The kinematic viscosity (25 ° C.) of the amino-modified silicone is preferably 50 to 500 mm ² / s, and the amino equivalent is preferably 3500 to 10000 g / mol.

The weight ratio of the amino-modified silicone to the polyoxyalkylene alkyl ether (amino-modified silicone / polyoxyalkylene alkyl ether) is preferably 75/25 to 98/2.

The polyoxyalkylene alkyl ether preferably contains a compound represented by the following general formula (1).
R ¹ -O- (AO) _n -H (1)
(In the general formula (1), R ¹ represents an alkyl group having 6 to 22 carbon atoms. AO represents an oxyalkylene group having 2 to 4 carbon atoms. N is a number of 1 to 7).

The peak area of the DTA curve measured by differential thermal analysis (DTA) of the polyoxyalkylene alkyl ether is preferably 2200 μV · s / mg or less.

The weight ratio of the amino-modified silicone to the non-volatile content of the treatment agent is preferably 50 to 95% by weight.

The acrylic fiber for carbon fiber production of the present invention is formed by adhering the above 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 a yarn-making process in which the above acrylic fiber treatment agent is attached to acrylic fiber, which is a raw material for carbon fiber for carbon fiber production, to make yarn, and flame resistance in an oxidizing atmosphere at 200 to 300 ° C. It includes a flame-resistant treatment step of converting into fibers and a carbonization treatment step of carbonizing the flame-resistant fibers in an inert atmosphere at 300 to 2000 ° C.

Since the acrylic fiber treatment agent of the present invention has excellent permeability into the inside of the fiber bundle at the initial stage of the flame resistance treatment step, the treatment agent can be uniformly applied to the inside of the fiber bundle and is treated at the latter stage of the flame resistance treatment step. Since the fibers can be protected by forming a film of the agent, fusion between the fibers and generation of fluff can be suppressed.
When the acrylic fiber of the present invention is used, fusion between the fibers and firing spots in the firing step can be suppressed, and carbon fibers having higher strength can be produced.

It is a figure explaining the peak area of the DTA curve by the differential thermal analysis (DTA) measurement.

[Acrylic fiber treatment agent]
The acrylic fiber treatment agent of the present invention is a treatment agent intended to be applied to acrylic fibers (carbon fiber precursors) used in carbon fiber production. The acrylic fiber treatment agent of the present invention contains an amino-modified silicone and a polyoxyalkylene alkyl ether, and the ratio P (10) defined by the following formula (A) is in the range of 0.01 to 0.5, and is described below. The ratio P (30) defined by the formula (A) is in the range of 0.01 to 1.5, and the ratio P (120) defined by the following formula (A) is in the range of 2.0 to 10. ..
P (t) = W2 (t) / (W1 (t) -W2 (t)) (A)
W1 (t): Weight (g) of the residue when the non-volatile content of the acrylic fiber treatment agent is heat-treated at 250 ° C. for t minutes.
W2 (t): The weight (g) of the residue after immersing the residue W1 (t) in chloroform to dissolve the soluble component and removing the chloroform-dissolving component by filtration.

The above W2 (t) is the residue of chloroform insoluble when the non-volatile component of the treatment agent is heat-treated at 250 ° C. for t minutes, and means a film component. "W1 (t) -W2 (t)" is a component obtained by removing the above-mentioned film component from the weight (g) of the residue when the non-volatile component of the treatment agent is heat-treated at 250 ° C. for t minutes, and the liquid component is used. means. Therefore, the ratio P (t) means the ratio (film component / liquid component) of the film component and the liquid component when the non-volatile component of the treatment agent is heat-treated at 250 ° C. for t minutes. The ratios P (10), P (30), and P (120) indicate the ratios of the film component and the liquid component when the non-volatile content of the treatment agent is heat-treated at 250 ° C. for 10 minutes, 30 minutes, and 120 minutes, respectively. The non-volatile component in the present invention refers to an absolute dry component when the treatment agent is heat-treated at 105 ° C. to remove a solvent or the like and reaches a constant amount. Detailed measurement methods for the non-volatile components, W1 and W2 are shown in Examples.
With such a configuration, the treatment agent can be uniformly applied to the inside of the fiber bundle at the initial stage of the flame resistance treatment step, and the treatment agent can be filmed to protect the fiber at the latter stage of the flame resistance treatment step. Therefore, according to the treatment agent of the present invention, fusion between fibers and generation of fluff can be suppressed.

The ratio P (10) is in the range of 0.01 to 0.5, preferably 0.01 to 0.3, more preferably 0.03 to 0.3, still more preferably 0.03 to 0.25. .. When the ratio P (10) is less than 0.01, the fiber focusing property is insufficient at the initial stage of the flame resistance treatment step. When the ratio P (10) is more than 0.5, the treatment agent cannot be uniformly applied to the inside of the fiber bundle at the initial stage of the flame resistance treatment step.
Further, from the viewpoint of heat resistance in the flame resistance treatment step and the effect of preventing fusion between fibers, the weight loss rate Q (10) when the non-volatile content of the treatment agent is heat-treated at 250 ° C. for 10 minutes is 30% by weight. Less than, preferably less than 25% by weight, even more preferably less than 20% by weight. When the weight loss rate Q (10) is 30% or more, the amount of the treatment agent remaining on the fibers in the flame resistance treatment step is reduced, and the effect of preventing fusion between the fibers may not be sufficiently obtained. The method for measuring the weight loss rate is shown in Examples.

The ratio P (30) is in the range of 0.01 to 1.5, preferably 0.05 to 1.5, more preferably 0.05 to 1.3, and even more preferably 0.05 to 1. When the ratio P (30) is less than 0.01, the focusing property is insufficient in the flame resistance treatment step. On the other hand, when the ratio P (30) exceeds 1.5, the treatment agent cannot be uniformly applied to the inside of the fiber bundle in the flame resistance treatment step.
Further, from the viewpoint of heat resistance in the flame resistance treatment step and the effect of preventing fusion between fibers, the weight loss rate Q (30) when the non-volatile content of the treatment agent is heat-treated at 250 ° C. for 30 minutes is 40% by weight. Less than, preferably less than 35% by weight, even more preferably less than 30% by weight. When the weight loss rate Q (30) is 40% or more, the amount of the treatment agent remaining on the fibers in the flame resistance treatment step is reduced, and the effect of preventing fusion between the fibers may not be sufficiently obtained.

The ratio P (120) is in the range of 2.0 to 10, preferably 3.0 to 9, more preferably 4.0 to 9, and even more preferably 5.0 to 9. When the ratio P (120) is less than 2.0, fiber protection cannot be performed in the latter stage of the flame resistance treatment step. On the other hand, when the ratio P (120) exceeds 10, the focusing property is insufficient in the latter stage of the flame resistance treatment step.
Further, from the viewpoint of heat resistance in the flame resistance treatment step and the effect of preventing fusion between fibers, the weight loss rate Q (120) when the non-volatile content of the treatment agent is heat-treated at 250 ° C. for 120 minutes is 50% by weight. Less than, preferably less than 45% by weight, even more preferably less than 40% by weight. When the weight loss rate Q (120) is 50% or more, the amount of the treatment agent remaining on the fibers in the flame resistance treatment step is reduced, and the effect of preventing fusion between the fibers may not be sufficiently obtained.

These ratios P (10), P (30), P (120) and weight loss rates Q (10), Q (30), Q (120) are amino-modified silicones and polyoxyalkylenes which are essential components of the treatment agent. It can be set by the type of alkyl ether, the ratio of these components, and the weight ratio of these components in the non-volatile content. Next, these will be described in detail.

(Amino-modified silicone)
The treatment agent of the present invention essentially contains amino-modified silicone. The amino group (including the organic group having an amino group) which is a modifying group of the amino-modified silicone may be bonded to the side chain of the silicone which is the main chain, may be bonded to the end, or may be bonded. Although it may be bonded to both, it is preferable that it is bonded to the side chain (having an amino group in the side chain) from the viewpoint of fiber protection in the flame resistance treatment step. Further, the amino group may be any of monoamine type, diamine type and polyamine type, and both may coexist in one molecule, but the treatment agent may be added to the inside of the fiber bundle in the flame resistance treatment step. The monoamine type or the diamine type is preferable from the viewpoint of uniformly applying the treatment agent and forming a film on the treatment agent to protect the fibers.

The kinematic viscosity of the amino-modified silicone at 25 ° C. is preferably 50 to 500 mm ² / s, more preferably 50 to 400 mm ² / s, still more preferably 50 to 300 mm ² / s, and even more preferably 50, from the viewpoint of exerting the effect of the present application. ~ 250 mm ² / s is particularly preferable. If the kinematic viscosity is less than 50 mm ² / s, the treatment agent may easily scatter, and the solution stability of the emulsion may deteriorate when emulsified in an aqueous system, making it impossible to uniformly apply the treatment agent to the fibers. .. As a result, fusion of fibers may not be prevented. When the kinematic viscosity is more than 500 mm ² / s, gum-up due to adhesiveness may become a problem.

The amino equivalent of the amino-modified silicone is preferably 3500 to 10000 g / mol, more preferably 4000 to 10000 g / mol, still more preferably 5000 to 9000 g / mol, from the viewpoint of preventing sticking and fusion between fibers. When the amino equivalent is less than 3500 g / mol, the treatment agent may not be uniformly applied to the inside of the fiber bundle because the treatment agent is thermally crosslinked at the initial stage of the flame resistance treatment step. Further, when the amino equivalent is 10,000 g / mol or more, fiber protection may not be possible because thermal cross-linking of the treatment agent does not occur in the latter stage of the flame resistance treatment step.

As the amino-modified silicone, a plurality of amino-modified silicones having different amino equivalents and kinematic viscosities (25 ° C.) may be used in combination. When two or more kinds of amino-modified silicones are used, the amino equivalent means the amino equivalent of the whole amino-modified silicone (mixture), and the kinematic viscosity at 25 ° C. means the kinematic viscosity of the whole amino-modified silicone (mixture). ..

（式（２）中、Ｒ^２は炭素数が１～２０のアルキル基又はアリール基を示す。Ｒ^３は下記化学式（３）で示される基である。Ｒ^４は、Ｒ^２、Ｒ^３又は－ＯＲ^１０(Ｒ^１０は水素原子又は炭素数が１～６のアルキル基)である。ｐは１０≦ｐ≦１００００、ｑは０．１≦ｑ≦１０００である。）Examples of the amino-modified silicone include compounds represented by the following general formula (2).

(In the formula (2), R ² represents an alkyl group or an aryl group having 1 to 20 carbon atoms. R ³ is a group represented by the following chemical formula (3). R ⁴ is R ² , R ³ or -OR ¹⁰ (R ¹⁰ 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 (2), R ² represents an alkyl group or an aryl group having 1 to 20 carbon atoms. ^R2 is preferably an alkyl group or an aryl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms, and further preferably a methyl group. The plurality of R ^2s in the formula (2) may be the same or different. R ³ is a group represented by the following general formula (3). R ⁴ is a group represented by R ² , R ³ or −OR ¹⁰ , preferably R ² . The plurality of ^R4s in the equation (2) may be the same or different. R ¹⁰ 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, and more preferably a hydrogen atom or a methyl group. p is a number of 10 to 10000, preferably 50 to 5000, and more preferably 100 to 2000. q is a number of 0.1 to 1000, preferably 0.5 to 500, and more preferably 1 to 100.

In the formula (3), R ⁵ and R ⁷ are independently alkylene groups having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms. R ⁶ , R ⁸ and R ⁹ are independently hydrogen atoms, alkyl or aryl groups having 1 to 10 carbon atoms, preferably hydrogen atoms or alkyl groups having 1 to 5 carbon atoms, and further. It is preferably a hydrogen atom. r is a number of 0 to 6, preferably 0 to 3, and more preferably 0 to 1.

The weight ratio of the amino-modified silicone to the non-volatile content of the treatment agent is preferably 50 to 95% by weight, more preferably 60 to 90% by weight, still more preferably 65 to 90% by weight. If the weight ratio is less than 50% by weight, the heat resistance of the treatment agent may be insufficient in the flame resistance treatment step. On the other hand, when the weight ratio exceeds 95% by weight, a stable aqueous emulsion may not be obtained when the treatment agent is aqueous emulsified.

(Polyoxyalkylene alkyl ether)
The treatment agent of the present invention essentially contains a polyoxyalkylene alkyl ether. By using amino-modified silicone and polyoxyalkylene alkyl ether in combination and setting the ratio P (10), the ratio P (30), and the ratio P (120) within the predetermined ranges, the fibers can be fused in the flame resistance treatment step. It can be suppressed. One kind or two or more kinds of polyoxyalkylene alkyl ethers may be used. The polyoxyalkylene alkyl ether is a compound having a structure in which an alkylene oxide is added to a saturated aliphatic alcohol. In the above general formula (1), R ¹ is an alkyl group and AO is an oxy having 2 to 4 carbon atoms. The alkylene group, n means a number of 1 or more.

Examples of the polyoxyalkylene alkyl ether include polyoxyethylene hexyl ether, polyoxyethylene heptyl ether, polyoxyethylene octyl ether, polyoxyethylene decyl ether, polyoxyethylene lauryl ether, polyoxyethylene tridecyl ether, and polyoxyethylene. Polyoxyalkylene linear alkyl ethers such as tetradecyl ether and polyoxyethylene cetyl ether; polyoxyalkylene branched primary alkyls such as polyoxyethylene 2-ethylhexyl ether, polyoxyethylene isocetyl ether and polyoxyethylene isostearyl ether. Ethers; polyoxyethylene 1-hexylhexyl ether, polyoxyethylene 1-octylhexyl ether, polyoxyethylene 1-hexyloctyl ether, polyoxyethylene 1-pentylheptyl ether, polyoxyethylene1-heptylpentyl ether, poly Polyoxyalkylene branched secondary alkyl ethers such as oxyethylene 1-hexyl heptyl ether, polyoxyethylene 1-heptyl hexyl ether, polyoxyethylene 1-pentylcaptyl ether, polyoxyethylene 1-captylpentyl ether and the like. Can be done.

The polyoxyalkylene alkyl ether preferably contains the compound (C) represented by the above general formula (1) indispensably from the viewpoint of exerting the effect of the present application. In the general formula (1), R ¹ is an alkyl group having 6 to 22 carbon atoms. When R ¹ has a hydrocarbon group other than the alkyl group and R ¹ has more than 22 carbon atoms, the polyoxyalkylene alkyl ether is tarred in the flame resistance treatment step, so that the precursor is converted into a flame resistant structure. May cause a decrease in the strength of carbon fiber. On the other hand, when the carbon number of R ¹ is less than 6, the solution stability of the emulsion when the treatment agent is aqueous-emulsified may deteriorate. The carbon number of R ¹ is preferably 8 to 20, more preferably 10 to 18, and even more preferably 10 to 16. The number of carbon atoms of R ¹ may be distributed, and R ¹ may be linear or have a branch.

A represents an alkylene group having 2 to 4 carbon atoms, and AO represents an oxyalkylene group. That is, it indicates an oxyethylene group, an oxypropylene group or an oxybutylene group. As the oxyalkylene group, an oxyethylene group and an oxypropylene group are preferable, and an oxyethylene group is more preferable. The number of repetitions of the oxyalkylene group, n, is a number of 1 to 7, preferably 2 to 7, and more preferably 3 to 7. When n is more than 7, fusion may occur because the treatment agent cannot be uniformly applied to the inside of the fiber bundle in the flame resistance treatment step when used in combination with the amino-modified silicone. The oxyalkylene group AO constituting the polyoxyalkylene group (AO) _n may be the same or different. N of AO is the number of moles of the oxyalkylene group added, and can be measured by ¹ H-NMR. ¹ Details of the measurement method by 1 H-NMR are shown in Examples.

The weight ratio of the compound (C) to the entire polyoxyalkylene alkyl ether is preferably 50% by weight or more, more preferably 70% by weight or more, further preferably 90% by weight or more, and particularly preferably 100% by weight. When the weight ratio is less than 50% by weight, fusion may occur because the treatment agent cannot be uniformly applied to the inside of the fiber bundle in the flame resistance treatment step when used in combination with the amino-modified silicone.

The peak (exothermic peak) area of the DTA curve measured by differential thermal analysis (DTA) of the polyoxyalkylene alkyl ether is preferably 2200 μV · s / mg or less, more preferably 2000 μV · s / mg or less, and 1800 μV · s / mg or less. More preferred. When the peak area exceeds 2200 μV · s / mg, fusion may occur because the treatment agent cannot be uniformly applied to the inside of the fiber bundle in the flame resistance treatment step when used in combination with the amino-modified silicone. Details of the measurement method of differential thermal analysis (DTA) are shown in Examples. When two or more kinds of polyoxyalkylene alkyl ethers are used, the peak area means the peak area of the entire polyoxyalkylene alkyl ether (mixture).

The weight ratio of the polyoxyalkylene alkyl ether to the non-volatile content of the treatment agent is preferably 2 to 25% by weight, more preferably 5 to 20% by weight, still more preferably 10 to 20% by weight. If the weight ratio is less than 2% by weight, a stable aqueous emulsion may not be obtained when the treatment agent is aqueous emulsified. 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 resistance treatment step.

The weight ratio of the amino-modified silicone to the polyoxyalkylene alkyl ether (amino-modified silicone / polyoxyalkylene alkyl ether) in the non-volatile content of the treatment agent of the present invention is preferably 75/25 to 98/2, and 80/20 to 95/5. Is more preferable, and 80/20 to 90/10 is even more preferable. When the weight ratio exceeds 98/2, it may not be possible to obtain a stable aqueous emulsion when the treatment agent is aqueous emulsified. On the other hand, if it is less than 75/25, the heat resistance of the treatment agent may be insufficient in the flame resistance treatment step.

(Surfactant)
The acrylic fiber treatment agent of the present invention may contain a surfactant other than the above-mentioned polyoxyalkylene alkyl ether as long as the effect of the present invention is not impaired. Surfactants are used as emulsifiers, antistatic agents and the like. The surfactant is not particularly limited, and a known one is appropriately selected from nonionic surfactants, anionic surfactants, cationic surfactants and amphoteric surfactants other than the above-mentioned polyoxyalkylene alkyl ether. Can be used. The surfactant may be used alone or in combination of two or more.

Examples of the nonionic surfactant other than the above polyoxyalkylene alkyl ether include polyoxyalkylene alkenyl ethers such as polyoxyethylene oleyl ether; polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenyl ether, and polyoxyethylene dodecyl. Polyoxyalkylene alkyl phenyl ethers such as phenyl ethers; polyoxyethylene tristylylphenyl ethers, polyoxyethylene distyrylphenyl ethers, polyoxyethylene styrylphenyl ethers, polyoxyethylene tribenzylphenyl ethers, polyoxyethylene dibenzylphenyl ethers, Polyoxyalkylene alkylarylphenyl ethers such as polyoxyethylene benzyl phenyl ether; polyoxyethylene monolaurates, polyoxyethylene monooleates, polyoxyethylene monostearates, polyoxyethylene monomyristylates, polyoxyethylene dilaurates, poly Polyoxyalkylene fatty acid esters such as oxyethylene diolate, polyoxyethylene dimyristylate, and polyoxyethylene distearate; sorbitan esters such as sorbitan monopalmitate and sorbitan monoolate; polyoxyethylene sorbitan monostearate, polyoxy Polyoxyalkylene sorbitan fatty acid ester such as ethylene sorbitan monooleate; glycerin fatty acid ester such as glycerin monostearate, glycerin monolaurate, glycerin monopalmitate; polyoxyalkylene sorbitol fatty acid ester; sucrose fatty acid ester; polyoxyethylene castor oil ether Polyoxyalkylene hardened bean oil ether such as polyoxyethylene-hardened bean oil ether; polyoxyalkylene-hardened bean oil ether such as polyoxyethylene-hardened bean oil ether; oxyethylene-oxypropylene block or random copolymer; oxyethylene-oxypropylene block or random copolymer terminal sucrose. Ethereal products; etc. can be mentioned. The weight average molecular weight of the nonionic surfactant is preferably 2000 or less, more preferably 200 to 1800, more preferably 300 to 1500, still more preferably 500 to 1000.

Examples of the anionic surfactant include fatty acid salts such as sodium oleate, potassium palmitate, and triethanolamine oleate; hydroxyl group-containing carboxylic acids (salts) such as potassium hydroxyacetate and potassium lactate; Polyoxyalkylene alkyl ether acetate salts such as polyoxyethylene tridecyl ether acetate (sodium salt); salts of carboxyl group polysubstituted aromatic compounds such as potassium trimellitic acid and potassium pyromellitic acid; dodecylbenzene sulfonic acid (sodium salt) Alkylbenzene sulfonates such as; polyoxyalkylene alkyl ether sulfonates such as polyoxyethylene 2-ethylhexyl ether sulfonic acid (potassium salt); stearoylmethyl taurine (sodium), lauroylmethyl taurine (sodium), myristylmethyl taurine (sodium). ), Higher fatty acid amide sulfonates such as palmitoylmethyl taurine (sodium); N-acylsarcosnates such as lauroyl sarcosic acid (sodium); alkylphosphonates such as octylphosphonate (potassium salt); phenylphosphonate (potassium salt) ) And other aromatic phosphonates; 2-ethylhexylphosphonate mono 2-ethylhexyl ester (potassium salt) and other alkylphosphonic acid alkylphosphorates; aminoethylphosphonic acid (diethanolamine salt) and other nitrogen-containing alkylphosphonates; Alkyl sulfate ester salts such as 2-ethylhexyl sulphate (sodium salt); polyoxyalkylene sulfate ester salts such as polyoxyethylene 2-ethylhexyl ether sulfate (sodium salt); sodium di-2-ethylhexyl sulfosuccinate, sodium dioctyl sulfosuccinate, etc. Long-chain N-acylglutamates such as long-chain sulfosuccinates, monosodium N-lauroyl glutamate, disodium N-stearoyl-L-glutamate; and the like.

Examples of the cationic surfactant include lauryltrimethylammonium chloride, myristyltrimethylammonium chloride, palmityltrimethylammonium chloride, stearyltrimethylammonium chloride, oleyltrimethylammonium chloride, cetyltrimethylammonium chloride, behenyltrimethylammonium chloride, and coconut oil alkyltrimethyl. Ammonium Chloride, Beef Alkyltrimethylammonium Chloride, Stearyltrimethylammonium Bromide, Palm Oil Alkyltrimethylammonium Bromide, Cetyltrimethylammonium Methosulfate, Oleyldimethylethylammonium Etosulfate, Dioctyldimethylammonium Chloride, Dilauryldimethylammonium Chloride, Distearyldimethylammonium Chloride , Octadecyl diethylmethylammonium sulfate, etc. Alkyl quaternary ammonium salts; (polyoxyethylene) laurylaminoether emulsion, stearylaminoether emulsion, di (polyoxyethylene) laurylmethylaminoetherdimethylphosphate, di (polyoxyethylene) (Polyoxyalkylene) such as (ethylene) lauryl ethylammonium etosulfate, di (polyoxyethylene) hardened beef alkylethylamine etosulfate, di (polyoxyethylene) laurylmethylammonium dimethyl phosphate, di (polyoxyethylene) stearylamine emulsion, etc. Alkylaminoether salt; acyls such as N- (2-hydroxyethyl) -N, N-dimethyl-N-stearoylamide propylammonium nitrate, lanolin fatty acid amidopropylethyldimethylammonium etosulfate, lauroylamide ethylmethyldiethylammonium metosulfate, etc. Amidoalkyl quaternary ammonium salts; alkylethenoxy quaternary ammonium salts such as dipalmitylpolyethenoxyethylammonium chloride, distearylpolyethenoxymethylammonium chloride; alkylisoquinolinium such as laurylisoquinolinium chloride. Salt; benzalconium salt such as lauryldimethylbenzylammonium chloride, stearyldimethylbenzylammonium chloride; benzyldimethyl {2- [2- (p-1,1,3,3-tetramethylbutylfe) Nooxy) etoxy] ethyl} benzethonium salt such as ammonium chloride; pyridinium salt such as cetylpyridinium chloride; imidazolinium salt such as oleylhydroxyethyl imidazolinium etosulfate, laurylhydroxyethyl imidazolinium etosulfate; N-cocoyl arginine ethyl Acylbasic amino acid alkyl ester salts such as ester pyrrolidone carboxylate, N-lauroyl lysine ethyl ethyl ester chloride; primary amine salts such as laurylamine chloride, stearylamine bromide, cured beef alkylamine chloride, rosinamine acetate; cetyl. Secondary amine salts such as methylamine sulfate, laurylmethylamine chloride, dilaurylamine acetate, stearylethylamine bromide, laurylpropylamine acetate, dioctylamine chloride, octadecylethylamine hydroxide; dilaurylmethylamine sulfate, lauryldiethylamine chloride. , Lauryl ethylmethylamine bromide, diethanol stearylamide ethylamine trihydroxyethyl phosphate salt, stearylamide ethylethanolamine urea polycondensate acetate and other tertiary amine salts; fatty acid amide guanidinium salt; lauryltriethylene glycol ammonium hydroxyoxide Alkyltrialkylene glycol ammonium salt and the like can be mentioned.

Examples of the amphoteric surfactant include 2-undecyl-N, N- (hydroxyethylcarboxymethyl) -2-imidazoline sodium, 2-cocoyl-2-imidazolinium hydroxide-1-carboxyethyroxy 2-sodium salt and the like. Imidazoline-based amphoteric surfactant; 2-heptadecyl-N-carboxymethyl-N-hydroxyethyl imidazolium betaine, lauryldimethylaminoacetic acid betaine, alkylbetaine, amide betaine, sulfobetaine and other betaine-based amphoteric surfactants; N- Examples thereof include amino acid-type amphoteric surfactants such as laurylglycine, N-lauryl β-alanine and N-stearyl β-alanine.

(Other ingredients)
The acrylic fiber treating agent of the present invention may contain components other than the above-mentioned components as long as the effects of the present invention are not impaired. Other components include acidic components, acidic phosphoric acid esters, phenol-based, amine-based, sulfur-based, phosphorus-based, quinone-based antioxidants; higher alcohol / higher alcohol ether sulfate ester salts, sulfonates, higher grades. Antistatic agents such as phosphate esters of alcohols and higher alcohol ethers, quaternary ammonium salt-type cationic surfactants, amine salt-type cationic surfactants; alkyl esters of higher alcohols, higher alcohol ethers, waxes, etc. Esters; antibacterial agents; preservatives; rust preventives; and hygroscopic agents.

Examples of acidic components include formic acid, acetic acid, lactic acid, hydroxyacetic acid, hydrochloric acid, nitrate, phosphoric acid, boric acid, hydrofluoric acid, butyric acid, crotonic acid, valeric acid, caproic acid, enanthic acid, capric acid and pelargonic acid. , Capric acid, lauric acid, myristic acid, myristoleic acid, pentadecanoic acid, palmitic acid, palmitreic acid, isosetyl acid, margaric acid, stearic acid, isostearic acid, oleic acid, ellaic acid, bacenoic acid, linoleic acid, linolenic acid, Arakidic acid, isoeicosaic acid, gadrainic acid, eicosenoic acid, docosanoic acid, isodocosanoic acid, erucic acid, tetracosanoic acid, isotetracosanoic acid, nervonic acid, cellotic acid, montanic acid, melicinic acid, oxalic acid, malonic acid, succinic acid, glutaric acid. , Adipic acid, Pimelic acid, Speric acid, Azelaic acid, Sebatic acid, Undencan diic acid, Dodecane diic acid, Tridecane diic acid, Tetradecane diic acid, Pentadecane diic acid, Sabit acid, Silica acid, Naftoic acid, Truilic acid, Phthal Acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, tartron acid, glyceric acid, hydroxybutyric acid, malic acid, tartaric acid, citramalic acid, citric acid, leucic acid, mevalonic acid, pantoic acid, lysynolic acid, lysine lysine acid , Celebronic acid, quinic acid, shikimic acid, salicylic acid, cleosortic acid, vanillic acid, syring acid, pyrocatechuic acid, resorcylic acid, protocatechuic acid, gentidic acid, orseric acid, gallic acid, mandelic acid, benzylic acid, atrolactic acid, Examples thereof include melilotoic acid, floretic acid, kumalic acid, umbellic acid, coffee acid, ferulic acid, synapic acid and derivatives thereof.

It is preferable that the treatment agent of the present invention contains substantially no acidic phosphoric acid ester. When the acid phosphate is contained, the treatment agent can be uniformly applied to the inside of the fiber bundle due to the effect of the acid phosphate in the early stage of the flame resistance step, but the effect of the acid phosphate disappears in the latter stage of the flame resistance step and the fiber. In some cases, the cohesiveness of the ester is insufficient. The term "substantially free" means that the weight ratio of the acidic phosphoric acid ester to the non-volatile content of the treatment agent is 0.5% by weight or less. The weight ratio is more preferably 0.3% by weight or less, further preferably 0.1% by weight or less, and particularly preferably 0% by weight.

The antioxidant is a component that effectively suppresses the thermal decomposition of the acrylic fiber treatment agent by heating in the flame resistance treatment step and enhances the effect of preventing fusion between fibers.
The antioxidant is not particularly limited, but an organic antioxidant is preferable from the viewpoint of preventing contamination of the firing furnace. Examples of the organic antioxidant include 4,4'-butylidenebis (3-methyl-6-t-butylphenol, trioctadecylphosphite, N, N'-diphenyl-p-phenylenediamine, triethyleneglycolbis [3- (3-t-Butyl-4-hydroxy-5-methylphenyl) propionate], dioleyl-thiodipropionate and the like. These organic antioxidants may be used alone or in combination of two or more. good.

It is preferable that the treatment agent of the present invention contains substantially no antioxidant. If an antioxidant is contained, the treatment agent may not form a film in the flame-resistant treatment step and may not be able to protect the fibers. In that case, the fusion of carbon fibers cannot be suppressed in the firing step, and carbon fibers having sufficient strength cannot be obtained. The term "substantially free" means that the weight ratio of the antioxidant to the non-volatile content of the treatment agent is 0.5% by weight or less. The weight ratio is more preferably 0.3% by weight or less, further preferably 0.1% by weight or less, and particularly preferably 0% by weight.

Further, the treating agent of the present invention may contain a modified silicone other than the above-mentioned amino-modified silicone as long as the effect of the present invention is not impaired. Examples of the modified silicone include aminopolyether-modified silicone, amide-modified silicone, amidopolyether-modified silicone, epoxy-modified silicone, polyether-modified silicone, epoxypolyether-modified silicone (see, for example, Patent No. 4616934), and carbinol-modified silicone. , Alkyl-modified silicone, phenol-modified silicone, methacrylate-modified silicone, alkoxy-modified silicone, fluorine-modified silicone and the like, one type of modified silicone may be used, or a plurality of modified silicones may be used in combination.

Further, the acrylic fiber treating agent of the present invention may contain an ester compound as long as the effect of the present invention is not impaired. Examples of the ester compound include an ester compound having three or more ester groups in the molecule described in Republished WO2007 / 066517, and a sulfur-containing ester described in the international application PCT / JP2013 / 75081. Compounds and the like can be mentioned.

The acrylic fiber treatment agent of the present invention is preferably in a state in which the amino-modified silicone and the polyoxyalkylene alkyl ether are dissolved, solubilized, emulsified or dispersed in water.
The weight ratio of water to the entire acrylic fiber treatment agent and the weight ratio of the non-volatile content are not particularly limited. For example, it may be appropriately determined in consideration of the transportation cost when transporting the acrylic fiber treatment agent of the present invention, the handleability due to the viscosity of the emulsion, and the like. The weight ratio of water to the entire acrylic fiber treatment 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 non-volatile content 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 treatment agent of the present invention can be produced by mixing the components described above. The method for emulsifying and dispersing the components described above is not particularly limited, and a known method can be adopted. Examples of such a method include a method in which each component constituting an acrylic fiber treatment agent is put into warm water under stirring to emulsify and disperse, or a method in which each component constituting an acrylic fiber treatment agent is mixed to form a homogenizer or homogenizer. Examples thereof include a method of gradually adding water to emulsify the phase inversion while applying a mechanical shearing force using a mixer, a ball mill, or the like.

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 may be used as a spinning oil for acrylic fibers other than precursors.

The viscosity of the non-volatile content of the acrylic fiber treatment agent of the present invention at 25 ° C. is preferably 10 to 10000 mPa · s from the viewpoint of imparting good fiber bundle focusing in the precursor yarn making process and flame resistance step. s is more preferable, and 50 to 1000 mPa · s is even more preferable. If the viscosity is less than 10 mPa · s, the focusing property of the fiber bundle in the precursor silk reeling step or the flame resistance step may be deteriorated. Further, when the viscosity exceeds 10000 mPa · s, the viscosity of the treating agent becomes too high and the handling of the treating agent deteriorates even if good focusing property of the fiber bundle in the precursor silk reeling step and the flame resistance step can be imparted. In some cases.

[Acrylic fiber for carbon fiber manufacturing, its manufacturing method and carbon fiber manufacturing method]
The acrylic fiber for carbon fiber production (precursor) of the present invention is produced by adhering the above acrylic fiber treatment agent to the raw material acrylic fiber of the precursor and producing yarn. The method for producing a precursor of the present invention includes a yarn-making step of adhering the acrylic fiber treatment agent to the raw material acrylic fiber of the precursor to make a yarn.
The method for producing carbon fiber of the present invention is a thread-making step of adhering the above acrylic fiber treatment agent to the acrylic fiber as a raw material of the precursor to make the precursor, and an oxidation of the precursor manufactured in the thread-making step at 200 to 300 ° C. It includes a flame-resistant treatment step of converting into flame-resistant fibers in a sexual atmosphere and a carbonization treatment step of carbonizing the flame-resistant fibers in an inert atmosphere at 300 to 2000 ° C.
According to the method for producing carbon fiber of the present invention, since the acrylic fiber treatment agent of the present invention is used, the treatment agent can be uniformly applied to the inside of the fiber bundle at the initial stage of the flame resistance treatment step, and the flame resistance can be increased. Since the treatment agent can be formed into a film to protect the fibers in the latter stage of the treatment step, fusion between the fibers and generation of fluff can be suppressed, and high-quality carbon fibers can be produced.

The yarn-making step is a step of adhering an acrylic fiber treatment agent to the raw acrylic fiber of the precursor to make the precursor, and includes an adhesion treatment step and a drawing step.
The adhesion treatment step is a step of spinning the raw material acrylic fiber of the precursor and then adhering the acrylic fiber treatment agent. That is, the acrylic fiber treatment agent is adhered to the raw material acrylic fiber of the precursor in the adhesion treatment step. Further, the raw material acrylic fiber of this precursor is drawn immediately after spinning, and the high-magnification drawing after the adhesion treatment step is particularly called a "drawing step". The stretching step may be a moist heat stretching method using high-temperature steam or a dry heat stretching method using a hot roller.

The precursor is composed of acrylic fibers containing polyacrylonitrile as a main component, which 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 acrylonitrile can be preferably 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 manufacturing cost. The number of single fibers constituting the fiber bundle of the precursor is also not particularly limited, but is preferably 1,000 to 96,000 from the viewpoint of the balance between performance and manufacturing cost.

The acrylic fiber treatment agent may be attached to the raw material acrylic fiber of the precursor at any stage of the yarn making process, but it is preferable to attach the acrylic fiber treatment agent once before the drawing step. It may be attached at any stage before the drawing step, for example, immediately after spinning. Further, it may be reattached at any stage after the stretching step, for example, it may be reattached immediately after the stretching step, it may be reattached at the winding step, or it may be reattached immediately before the flame resistance treatment step. You may let me. As for the method of adhesion, it may be attached using a roller or the like, or it may be attached by a dipping method, a spray method or the like.

In the adhesion treatment step, the application rate of the acrylic fiber treatment agent is to obtain the effect of preventing sticking between fibers and the effect of preventing fusion, and in the carbonization treatment step, the tarification of the treatment agent prevents deterioration of the quality of carbon fibers. From the balance with the above, it is preferably 0.1 to 2% by weight, more preferably 0.3 to 1.5% by weight, based on the weight of the precursor. If the application rate of the acrylic fiber treating agent is less than 0.1% by weight, the sticking and fusion between the single fibers cannot be sufficiently prevented, and the strength of the obtained carbon fibers may decrease. On the other hand, when the application rate of the acrylic fiber treatment agent is more than 2% by weight, the acrylic fiber treatment agent covers the spaces between the single fibers more than necessary, so that the supply of oxygen to the fibers is hindered in the flame resistance treatment step, which is obtained. The strength of carbon fiber may decrease. The application rate of the acrylic fiber treatment agent referred to here is defined as a percentage of the weight of the non-volatile component to which the acrylic fiber treatment agent is attached to the weight of the precursor.

The flame-resistant treatment step is a step of converting the precursor to which the acrylic fiber treatment agent is attached into flame-resistant fibers in an oxidizing atmosphere at 200 to 300 ° C. The oxidizing atmosphere may be usually an air atmosphere. The temperature of the oxidizing atmosphere is preferably 230 to 280 ° C. In the flame resistance treatment step, the acrylic fiber after the adhesion treatment is tensioned at a draw ratio of 0.90 to 1.10 (preferably 0.95 to 1.05) for 20 to 100 minutes (preferably 30). Heat treatment is performed for ~ 60 minutes). In this flame-resistant treatment, a flame-resistant fiber having a flame-resistant structure is produced through intramolecular cyclization and addition of oxygen to the ring.

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, first, in a firing furnace having a temperature gradient from 300 ° C. to 800 ° C. in an inert atmosphere such as nitrogen and argon, a tension with a draw ratio of 0.95 to 1.15 with respect to the flame-resistant fiber is obtained. It is preferable to perform a pre-carbonization treatment step (first carbonization treatment step) by heat-treating for several minutes while applying the above. After that, in order to further promote carbonization and graphitization, a tension with a draw ratio of 0.95 to 1.05 is applied to the first carbonization treatment step in an inert atmosphere such as nitrogen and argon. The flame-resistant fiber is carbonized by performing a second carbonization treatment step by heat-treating for several minutes while applying. Regarding the control of the heat treatment temperature in the second carbonization treatment step, it is preferable to set the maximum temperature to 1000 ° C. or higher (preferably 1000 to 2000 ° C.) while applying a temperature gradient. This maximum temperature is appropriately selected and determined according to the required characteristics (tensile strength, elastic modulus, etc.) of the desired carbon fiber.

In the method for producing carbon fibers of the present invention, if carbon fibers having a higher elastic modulus are desired, a graphitization treatment step can be performed following the carbonization treatment step. The graphitization treatment step is usually carried out 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 or argon.

The carbon fibers thus obtained can be surface-treated to increase the adhesive strength with the matrix resin when used as a composite material, depending on the purpose. A vapor phase or liquid phase treatment can be adopted as the surface treatment method, and from the viewpoint of productivity, the liquid phase treatment with an electrolytic solution such as an acid or an alkali is preferable. Further, in order to improve the processability and handleability of the carbon fiber, various sizing agents having excellent compatibility with the matrix resin can be added.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to the examples described here. The percentages and parts shown in the following examples are "% by weight" and "parts by weight" unless otherwise specified. The measurement of each characteristic value was performed based on the method shown below. In addition, Examples 3, 4, 6, 7 , 8 and 14 are referred to as reference examples.

<Non-volatile content of treatment agent, ratio P (t), weight loss rate Q (t)>
Each treatment agent emulsion was collected on an aluminum cup having a diameter of φ60 mm so that the non-volatile content was 1 g, treated with a warm air dryer at 105 ° C. for 3 hours to remove water, and the sample was precisely weighed (W).
The obtained sample (W) was heat-treated in a gear oven under each temperature condition (250 ° C. × t minutes (t = 10, 30, 120)), and the sample was precisely weighed (W1 (t)) (g). The heat-treated sample (W1 (t)) is dissolved in chloroform and separated into a soluble portion and an insoluble portion. Chloroform was treated from the insoluble portion at room temperature for 3 hours at 80 ° C. for 20 minutes, and the sample from which chloroform was removed was precisely weighed (W2 (t)) (g). The ratio P (t) was calculated by the following formula (A). Further, the weight reduction rate Q (t) was calculated by the following formula (B).
P (t) = W2 (t) / (W1 (t) -W2 (t)) (A)
Q (t) (wt%) = [(W-W1 (t)) / W] x 100 (B)

< ¹ AO measurement of polyoxyalkylene alkyl ether by 1 H-NMR method>
About 30 mg of the measurement sample is weighed in a sample tube for NMR having a diameter of 5 mm, and about 0.5 ml of deuterated chloroform is added and dissolved as a deuterated solvent. Then, about 0.1 ml of trifluoroacetic anhydride was added to prepare a sample for analysis, and the sample was measured with a ¹ H-NMR measuring device (AVANCE 400, 400 MHz manufactured by BRUKER). From the obtained NMR chart, the peak area of the polyoxyalkylene alkyl ether appearing at 0.5 ppm to 1.8 ppm derived from the proton of the alkyl group and the peak area appearing at 3.0 ppm to 4.0 ppm derived from the proton of the polyoxyalkylene are found. The number of added moles of the oxyalkylene group was calculated. However, when the number of carbon atoms of the alkyl group is distributed, the number of carbon atoms in the center is used.

<Measurement of peak area of DTA curve by differential thermal analysis (DTA) measurement>
About 3 mg of polyoxyalkylene alkyl ether was taken in an aluminum pan of known weight, and DTA was measured. The polyoxyalkylene alkyl ether contained in the aluminum pan is set on a differential thermal balance TG-8120 (manufactured by Rigaku Co., Ltd.), and the temperature is raised from 25 ° C to 500 ° C in the air at a heating rate of 20 ° C / min, and the exothermic peak is generated. A DTA curve with As shown in FIG. 1, the value (μV · s) calculated by the integral value of the area surrounded by the straight line extending in the y-axis direction and the DTA curve, with the portion where the heat flow rate hardly changes as the baseline. / Mg) was defined as the peak area of the DTA curve.

<Rating rate of treatment agent>
The precursor after the treatment agent was added was alkaline-melted with potassium hydroxide / sodium butyrate, then dissolved in water and adjusted to pH 1 with hydrochloric acid. This was colored by adding sodium sulfite and ammonium molybdate, and the specific color of molybdenum blue was quantified (wavelength 815 mμ) to determine the silicon content. The addition rate (% by weight) of the acrylic fiber treatment agent was calculated by using the silicon content obtained here and the value of the silicon content in the treatment agent obtained in advance by the same method.

<Anti-fusing property>
Twenty places were randomly selected from the carbon fibers, short fibers having a length of 10 mm were cut out from them, the fused state was observed, and the judgment was made according to the following evaluation criteria.
◎: No fusion ○: Almost no fusion △: Less fusion ×: More fusion

<Carbon fiber strength>
The measurement was performed according to the epoxy resin impregnated strand method specified in JIS-R-7601, and the average value of 10 measurements was taken as the carbon fiber strength (GPa).

[Example 1]
Amino-modified silicone A1, polyoxyethylene alkyl ether C2 and water are mixed and water-based emulsified so as to have the non-volatile content composition of the treatment agent shown in Table 1, and the weight ratio of the amino-modified silicone A1 to the non-volatile content of the treatment agent. A treatment agent (precursor treatment agent) having a weight ratio of 85% by weight and a weight ratio of polyoxyethylene alkyl ether C2 of 15% by weight was prepared. The non-volatile content concentration of the treatment agent was 20% by weight.
Then, the prepared treatment agent was further diluted with water to obtain a treatment liquid having a non-volatile content concentration of 3.0% by weight.
The treatment liquid was adhered to the acrylic fiber as the raw material of the precursor obtained by copolymerizing 97 mol% acrylonitrile and 3 mol% itaconic acid so as to have an imparting rate of 1.0%, and a drawing step (steam stretching, stretching ratio) was performed. A precursor was prepared through (2.1 times) (single fiber fineness 0.8 dtex, 24,000 filaments). This precursor was flame-resistant in a flame-resistant furnace at 250 ° C. for 60 minutes, and then fired in a carbonization furnace having a temperature gradient of 300 to 1400 ° C. under a nitrogen atmosphere to convert it into carbon fibers. Table 1 shows the evaluation results of each characteristic value.

[Examples 2 to 14, Comparative Examples 1 to 12]
In Example 1, the precursor and carbon fiber after the treatment agent was attached were obtained in the same manner as in Example 1 except that the treatment liquid was adjusted so as to have the non-volatile content composition of the treatment agent shown in Tables 1 to 4. The evaluation results of each characteristic value are shown in Tables 1 to 4.

The details of the non-volatile components in Tables 1 to 4 are as follows.
<Amino-modified silicone>
Amino-modified silicone A1 (25 ° C viscosity: 110 mm ² / s, amino equivalent: 5000 g / mol, monoamine type)
Amino-modified silicone A2 (25 ° C viscosity: 250 mm ² / s, amino equivalent: 7600 g / mol, diamine type)
Amino-modified silicone A3 (25 ° C viscosity: 90 mm ² / s, amino equivalent: 8800 g / mol, monoamine type)
Amino-modified silicone A4 (25 ° C viscosity: 60 mm ² / s, amino equivalent: 6000 g / mol, diamine type)
Amino-modified silicone B1 (25 ° C viscosity: 1300 mm ² / s, amino equivalent: 1700 g / mol, diamine type)
Amino-modified silicone B2 (25 ° C viscosity: 220 mm ² / s, amino equivalent: 1500 g / mol, diamine type)
Amino-modified silicone B3 (25 ° C viscosity: 1700 mm ² / s, amino equivalent: 3800 g / mol, monomine type)

<Polyoxyethylene alkyl ether>
Polyoxyethylene alkyl ether C1: Alkyl ether having 12 to 14 carbon atoms with 2.8 mol of oxyethylene group added.
Polyoxyethylene alkyl ether C2: Alkyl ether with 5.0 mol of oxyethylene group added 12 to 14 carbon atoms Polyoxyethylene alkyl ether C3: 6.9 mol of oxyethylene group added with 12 to 14 carbon atoms 14 alkyl ethers Polyoxyethylene alkyl ether D1: 8.6 mol of oxyethylene group added Alkyl ether with 12 to 14 carbon atoms Polyoxyethylene alkyl ether D2: 11.7 mol of oxyethylene group added carbon Alkyl ether with a number of 12 to 14 Polyoxyethylene alkyl ether C4: 2.9 mol of oxyethylene group added Alkyl ether with 12 carbon number Polyoxyethylene alkyl ether C5: 4.9 mol of oxyethylene group added Alkyl ether with 12 carbon atoms Polyoxyethylene alkyl ether C6: 5.8 mol of oxyethylene group added Alkyl ether with 12 carbon atoms Polyoxyethylene alkyl ether D3: 8.9 mol of oxyethylene group added Alkyl ether having 12 carbon atoms The number of added moles of the oxyethylene group is ^a value calculated from the result measured by the 1H-NMR method.

Cationic Surfactant: N-Ethyl-N, N-Bis (2-Hydroxyethyl) Lauryl Ammonium Ethyl Sulfate Hydrochloric Acid Inhibitor: 4,4'-Butylidenebis (3-Methyl-6-Tert-Butylphenyl-Ditri) Desirphos Fight)
Acidic component: acetic acid

Acidic Phosphate Ester: The mixture p-1 obtained in the following production example was used.
In a reaction vessel under a nitrogen stream, 976 parts of an alkyl ether having 11 to 15 carbon atoms (with a theoretical molecular weight of 728 and 13 carbon atoms) to which 12 mol of an oxyethylene group was added was charged and heated to about 65 ° C. under stirring. Next, 24 parts of anhydrous phosphoric acid P ₂ O ₅ (theoretical molecular weight 142) was added under stirring and esterified at about 80 ° C. for 2 hours to allow unreacted polyoxyethylene alkyl ether and polyoxyethylene alkyl phosphate P. A mixture p-1 containing -1 was obtained. The acid value of the mixture p-1 was 28.8 mgKOH / g, and the molar equivalent of anhydrous phosphoric acid to 1 mol of polyoxyethylene alkyl ether was 0.252. The theoretical molecular weight is a formula weight obtained based on a chemical formula.
The weight ratio of the polyoxyethylene alkyl phosphate P-1 in the mixture p-1 was 35.3 wt% by anion exchange chromatography. Therefore, the acid value of polyoxyethylene alkyl phosphate P-1 is 81.6 mgKOH / g (28.8 / 0.353). The molar ratio of phosphoric acid monoester to phosphoric acid diester was 59.4 / 40.6.

In the examples using the treatment agents in which the ratios P (10), P (30) and P (120) are in a predetermined range, all of them have excellent permeability into the fiber bundle at the initial stage of the flame resistance treatment step. Since the treatment agent can be uniformly applied to the inside of the fiber bundle and the fibers can be protected by forming a film of the treatment agent in the latter stage of the flame resistance treatment step, fusion between the fibers and the generation of fluff are suppressed. The carbon fiber strength is excellent because it can be used.
On the other hand, in the comparative example using the treatment agent in which the ratios P (10), P (30) and P (120) are not in the predetermined range, the fusion between the fibers and the generation of fluff cannot be suppressed, so that the carbon fiber strength Is inferior.

The acrylic fiber treatment agent of the present invention is a treatment agent used when producing acrylic fiber for carbon fiber production, and is useful for producing high-quality carbon fiber. The acrylic fiber for producing carbon fiber of the present invention has been treated with the treatment agent of the present invention and is useful for producing high-quality carbon fiber. High-quality carbon fiber can be obtained by the method for producing carbon fiber of the present invention.

Claims (5)

Acrylic fiber treatment agent containing amino-modified silicone and polyoxyalkylene alkyl ether.
The amino-modified silicone has an amino group in the side chain, the kinematic viscosity (25 ° C.) of the amino-modified silicone is 50 to 500 mm ² / s, and the amino equivalent is 3500 to 10000 g / mol.
The polyoxyalkylene alkyl ether is a compound represented by the following general formula (1).
The weight ratio of the amino-modified silicone to the polyoxyalkylene alkyl ether (amino-modified silicone / polyoxyalkylene alkyl ether) is 75/25 to 85/15.
The ratio P (10) defined by the following formula (A) is in the range of 0.01 to 0.5.
The ratio P (30) defined by the following formula (A) is in the range of 0.62 to 1.5.
The ratio P (120) defined by the following formula (A) is in the range of 5.0 to 9.2 .
Acrylic fiber treatment agent.
R ¹ -O- (AO) _n -H (1)
(In the general formula (1), R ¹ represents an alkyl group having 6 to 22 carbon atoms. AO represents an oxyalkylene group having 2 to 4 carbon atoms. N is a number of 1 to 7).
P (t) = W2 (t) / (W1 (t) -W2 (t)) (A)
W1 (t): Weight (g) of the residue when the non-volatile content of the acrylic fiber treatment agent is heat-treated at 250 ° C. for t minutes.
W2 (t): The weight (g) of the residue after immersing the residue W1 (t) in chloroform to dissolve the soluble component and removing the chloroform-dissolving component by filtration. The treatment agent according to claim 1, wherein the peak area of the DTA curve measured by differential thermal analysis (DTA) of the polyoxyalkylene alkyl ether is 2200 μV · s / mg or less. The treatment agent according to claim 1 or 2, wherein the weight ratio of the amino-modified silicone to the non-volatile content of the treatment agent is 50 to 95% by weight. Acrylic fiber for carbon fiber production, which is obtained by adhering the acrylic fiber treatment agent according to any one of claims 1 to 3 to the raw material acrylic fiber for acrylic fiber for carbon fiber production. A yarn-making step of adhering the acrylic fiber treatment agent according to any one of claims 1 to 3 to the raw material acrylic fiber of acrylic fiber for carbon fiber production to make a yarn, and a flame-resistant fiber in an oxidizing atmosphere at 200 to 300 ° C. A method for producing carbon fiber, which comprises a flame-resistant treatment step of converting into flame-resistant fiber and a carbonization treatment step of carbonizing the flame-resistant fiber in an inert atmosphere at 300 to 2000 ° C.

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