JP6056517B2 - Sizing agent-coated carbon fiber, method for producing sizing agent-coated carbon fiber, prepreg, and carbon fiber-reinforced thermoplastic resin composition - Google Patents

Description

  The present invention relates to a sizing agent-coated carbon fiber that is suitably used for aircraft members, spacecraft members, automobile members, marine members, sports applications such as golf shafts and fishing rods, and other general industrial applications, and the sizing agent coating. The present invention relates to a method for producing carbon fiber. The present invention also relates to a prepreg using the carbon fiber coated with the sizing agent, a carbon fiber reinforced thermoplastic resin composition, and a carbon fiber reinforced composite material formed by molding any of them. More specifically, in the present invention, the sizing agent-coated carbon fiber is excellent in bundling and smoothness, and has excellent adhesion between the matrix resin and the carbon fiber. The sizing agent-coated carbon fiber manufacturing method, prepreg, and The present invention relates to a carbon fiber reinforced thermoplastic resin composition and a carbon fiber reinforced composite material formed by molding any of them.

  Since carbon fiber is lightweight and has excellent strength and elastic modulus, many composite materials combined with various matrix resins are used for aircraft members, spacecraft members, automobile members, ship members, civil engineering and building materials, and sporting goods. Used in the field. In a composite material using carbon fibers, in order to make use of the excellent characteristics of carbon fibers, it is important that the adhesion between the carbon fibers and the matrix resin is excellent.

  In order to improve the adhesion between the carbon fiber and the matrix resin, a method of introducing an oxygen-containing functional group on the surface of the carbon fiber is usually performed by subjecting the carbon fiber to oxidation treatment such as gas phase oxidation or liquid phase oxidation. . For example, a method of improving the interlaminar shear strength, which is an index of adhesiveness, by subjecting carbon fibers to electrolytic treatment has been proposed (see Patent Document 1). However, in recent years, as the level of required properties for composite materials has improved, the adhesion that can be achieved by such oxidation treatment alone is becoming insufficient.

  On the other hand, since carbon fiber is brittle and has poor convergence and friction resistance, fluff and yarn breakage are likely to occur in the high-order processing step. For this reason, the method of apply | coating to carbon fiber is proposed (refer patent document 2 and 3).

  For example, compounds having a plurality of aliphatic type epoxy groups have been proposed as sizing agents (see Patent Documents 4, 5, and 6). Further, a method of applying an epoxy adduct of polyalkylene glycol as a sizing agent to carbon fibers has been proposed (see Patent Documents 7, 8 and 9).

  In addition, a method of applying diglycidyl ether of bisphenol A to carbon fibers as an aromatic sizing agent has been proposed (see Patent Documents 2 and 3). In addition, a method of applying a polyalkylene oxide adduct of bisphenol A as a sizing agent to carbon fibers has been proposed (see Patent Documents 10 and 11). In addition, a method of applying a bisphenol A polyalkylene oxide adduct having an epoxy group added thereto to a carbon fiber as a sizing agent has been proposed (see Patent Documents 12 and 13).

  Although the above-described sizing agent can impart adhesion and convergence to the carbon fiber, a sizing agent composed of one kind of epoxy compound is not sufficient, and two or more kinds of epoxy compounds are used in combination depending on the desired function. Techniques have been proposed in recent years.

  For example, a sizing agent that combines two or more epoxy compounds that define surface free energy has been proposed (see Patent Documents 14 to 17). Patent Document 14 discloses a combination of an aliphatic epoxy compound and an aromatic epoxy compound. According to Patent Document 14, the sizing agent that is abundant in the outer layer has a blocking effect against the atmosphere with respect to the sizing agent component that is abundant in the inner layer, and the epoxy group is prevented from opening due to moisture in the atmosphere. . Moreover, in this patent document 14, about the preferable range of a sizing agent, the ratio of an aliphatic epoxy compound and an aromatic epoxy compound is prescribed | regulated as 10 / 90-40 / 60, and the one where the amount of aromatic epoxy compounds is larger is suitable. Has been.

  Patent Documents 16 and 17 disclose a sizing agent using two or more epoxy compounds having different surface free energies. The Patent Documents 16 and 17 mainly aim to improve the permeability of a matrix resin by using a sizing agent containing two or more epoxy compounds having different surface free energies, and two or more epoxy compounds. The combination of the aromatic epoxy compound and the aliphatic epoxy compound is not limited as a combination of the above, and there is no general illustration of the aliphatic epoxy compound selected from the viewpoint of adhesiveness.

  Furthermore, the sizing agent which mix | blends a bisphenol A type epoxy compound and aliphatic polyepoxy resin by mass ratio 50 / 50-90 / 10 is disclosed (refer patent document 18). However, Patent Document 18 also has a large amount of bisphenol A type epoxy compound, which is an aromatic epoxy compound.

  In addition, as a sizing agent that defines a combination of an aromatic epoxy compound and an aliphatic epoxy compound, a polyfunctional aliphatic compound on the surface of the carbon fiber bundle, an epoxy resin on the upper surface, an alkylene oxide adduct and an unsaturated dibasic acid A combination of a condensate and an alkylene oxide adduct of phenols is disclosed (see Patent Document 19).

  Furthermore, as a combination of two or more epoxy compounds, a combination of an aliphatic epoxy compound and a bisphenol A type epoxy compound that is an aromatic epoxy compound is disclosed. The aliphatic epoxy compound is a cycloaliphatic epoxy compound and / or a long-chain aliphatic epoxy compound (see Patent Document 20).

  Further, combinations of epoxy compounds having different properties are disclosed. A combination of two epoxy compounds that are liquid and solid at 25 ° C. is disclosed (see Patent Document 21). Furthermore, combinations of epoxy resins having different molecular weights, and combinations of monofunctional aliphatic epoxy compounds and epoxy resins have been proposed (see Patent Documents 22 and 23).

  However, the adhesive property and the high sizing property and smoothness of the sizing agent-coated carbon fiber are the sizing agent (for example, see Patent Documents 20 to 23) in which two or more types of epoxy compounds are mixed, the epoxy compound and a specific condensate. The actual situation is that it cannot be said that the above combination (see Patent Document 19) can be satisfied at the same time. The reason is that in order to satisfy the high adhesiveness and the high sizing property and smoothness of the carbon fiber coated with the sizing agent, it is considered necessary to satisfy the following three requirements. This is because they did not meet these requirements. The first of the three requirements is that an epoxy component with high adhesiveness is present inside the sizing layer (carbon fiber side), and the carbon fiber and the epoxy compound in the sizing interact strongly. In the surface layer of the sizing layer (matrix resin side), there is a compound having a specific structure that gives higher convergence and smoothness than the adhesion to the carbon fiber in the inner layer, and the third is that the matrix resin and In order to improve the adhesive property, the sizing agent surface layer (matrix resin side) must have a chemical composition capable of strong interaction with the matrix resin. And these three requirements are achieved only when a specific compound combination and a sizing agent surface structure are used.

  For example, Patent Document 14 discloses that the sizing agent has an inclined structure in order to enhance the adhesion between the carbon fiber and the sizing agent, but Patent Document 14 and any other documents (Patent Documents 15 to 15). 18) and the like, it can be said that there is no idea of simultaneously satisfying the adhesiveness and the sizing agent-coated carbon fibers by arranging a compound that enhances the sizing property and smoothness on the surface of the sizing layer.

  Patent Document 19 discloses that a polyfunctional aliphatic compound is present in the inner layer of the sizing agent, and an aromatic epoxy resin and an aromatic reactant are present, which is expected to improve convergence and smoothness. However, since there is no polyfunctional aliphatic epoxy compound having high adhesion on the surface layer of the sizing agent, it is difficult to achieve high adhesion with the matrix resin.

Japanese Patent Laid-Open No. 04-361619 US Pat. No. 3,957,716 JP-A-57-171767 Japanese Examined Patent Publication No. 63-14114 JP-A-7-279040 JP-A-8-113876 JP-A-57-128266 U.S. Pat. No. 4,555,446 JP 62-033872 A JP 07-009444 A JP 2000-336577 A JP 61-028074 A Japanese Patent Laid-Open No. 01-272867 JP 2005-179826 A JP 2005-256226 A International Publication No. 03/010383 JP 2008-280624 A JP 2005-213687 A JP 2002-309487 A Japanese Patent Laid-Open No. 02-307979 JP 2002-173873 A JP 59-71479 A JP 58-41973 A

  The present invention has been made in view of the above, and is provided with a sizing agent-coated carbon fiber and a sizing that can obtain a carbon fiber-reinforced composite material having excellent adhesiveness, high convergence and smoothness, and excellent mechanical strength. It is an object to provide a method for producing an agent-coated carbon fiber, a prepreg, and a carbon fiber reinforced thermoplastic resin composition.

  The inventors of the present invention have found that the above-described object can be achieved by using carbon fiber having a specific chemical composition on the surface of the sizing agent, using a sizing agent in which a plurality of specific compounds are combined. That is, in the present invention, a known sizing agent can be used as the individual sizing agent itself, but it is important as a sizing method that the surface of the sizing agent has a specific chemical composition in a combination of specific compounds. And it can be said to be new.

In order to solve the above-mentioned problems and achieve the object, the sizing agent-coated carbon fiber of the present invention is a carbon fiber coated with a sizing agent containing at least (A) to (C), and the surface of the sizing agent is photoelectron. Height of component (cps) of binding energy (284.6 eV) attributed to (a) CHx, C—C, C═C of C _1s core spectrum measured by X-ray photoelectron spectroscopy at an escape angle of 15 ° ) And (b) the ratio (a) / (b) of the height (cps) of the component of the binding energy (286.1 eV) attributed to C—O is 0.50 to 0.90, To do.
(A) Aliphatic epoxy compound (B) Condensate of unsaturated dibasic acid and alkylene oxide adduct of bisphenols (C) Nonionic surfactant containing an aromatic ring.

  In the sizing agent-coated carbon fiber of the present invention, the aliphatic epoxy compound (A) has an epoxy value of 2.0 to 8.0 meq / g and a hydroxyl value of 2.0 to 5.0 meq / g in the above invention. And having two or more epoxy groups in the molecule.

  The sizing agent-coated carbon fiber of the present invention is characterized in that, in the above invention, the interfacial shear strength between the single fiber of the sizing agent-coated carbon fiber and the epoxy resin is 40 MPa or more.

  The sizing agent-coated carbon fiber of the present invention is the condensate (B) of the aliphatic epoxy compound (A), unsaturated dibasic acid and alkylene oxide adduct of bisphenols contained in the sizing agent in the above invention. The ratio (A) / (B) is 52/48 to 80/20.

  The sizing agent-coated carbon fiber of the present invention is an aliphatic epoxy compound eluted when the sizing agent applied by sonicating the sizing agent-coated fiber with an acetonitrile / chloroform mixed solvent is eluted in the above invention. The proportion of (A) is 0.3 parts by mass or less with respect to 100 parts by mass of the sizing agent-coated carbon fiber.

  The sizing agent-coated carbon fiber of the present invention is the above-described invention, wherein the aliphatic epoxy compound (A) is selected from glycerol, diglycerol, polyglycerol, trimethylolpropane, pentaerythritol, sorbitol, and arabitol. It is characterized by being a glycidyl ether type epoxy compound obtained by reaction with epichlorohydrin.

In addition, the sizing agent-coated carbon fiber of the present invention is the above-described invention, wherein the C1s inner-shell spectrum (a) CHx, C- The height (cps) of the component of the bond energy (284.6 eV) attributed to C, C = C, and the height (cps) of the component of the bond energy (286.1 eV) attributed to (B) C—O. ) And (I) and (II) determined from the ratio (a) / (b) satisfy the relationship (III).
(I) Value of (a) / (b) on the surface of the sizing agent-coated carbon fiber before sonication (II) Sizing agent adhesion by sonicating the sizing agent-coated carbon fiber in an acetone solvent (A) / (b) value (III) 0.50 ≦ (I) ≦ 0.90 and 0.6 <on the surface of the sizing agent-coated carbon fiber washed to 0.09 to 0.20 mass%. (II) / (I) <1.0.

  The sizing agent-coated carbon fiber of the present invention is characterized in that, in the above invention, the sizing agent contains an aromatic epoxy compound (D).

  The sizing agent-coated carbon fiber of the present invention is characterized in that, in the above invention, the aromatic epoxy compound (D) is a bisphenol A type epoxy compound or a bisphenol F type epoxy compound.

Moreover, the manufacturing method of the sizing agent application | coating carbon fiber of this invention is a manufacturing method of the sizing agent application | coating carbon fiber which apply | coats the sizing agent which contains at least (A)-(C) to carbon fiber in the said invention, After the sizing agent is applied to the carbon fiber, the sizing agent-coated carbon fiber according to any one of the above is manufactured by heat treatment for 30 to 600 seconds in a temperature range of 160 to 260 ° C.
(A) Aliphatic epoxy compound (B) Condensation product of unsaturated dibasic acid and alkylene oxide adduct of bisphenol (C) Nonionic surface active substance containing an aromatic ring In addition, the sizing agent-coated carbon fiber of the present invention The production method of the present invention comprises a composition comprising at least an aqueous emulsion liquid containing at least a condensate (B) of an unsaturated dibasic acid and an alkylene oxide adduct of bisphenols and an aliphatic epoxy compound (A). The mixed sizing agent-containing liquid is applied to carbon fibers.

  Moreover, the manufacturing method of the sizing agent application | coating carbon fiber of this invention is the said invention, After apply | coating the said sizing agent containing liquid, after carrying out liquid phase electrolytic oxidation of the said carbon fiber in alkaline electrolyte.

  Further, the prepreg of the present invention is a sizing agent-coated carbon fiber according to any one of the above, or a sizing agent-coated carbon fiber produced by the method for producing a sizing agent-coated carbon fiber according to any one of the above. And a thermosetting resin.

  The prepreg of the present invention is characterized in that, in the above invention, the thermosetting resin contains an epoxy compound (E) and a latent curing agent (F).

  Moreover, the carbon fiber reinforced thermoplastic resin composition of the present invention is produced by the method for producing a sizing agent-coated carbon fiber according to any one of the above, or a sizing agent-coated carbon fiber according to any one of the above. The sizing agent-coated carbon fiber and the thermoplastic resin (G) are contained.

  Moreover, the carbon fiber reinforced thermoplastic resin composition of the present invention is the above-described invention, wherein the thermoplastic resin (G) is a polyarylene sulfide resin, a polyether ether ketone resin, a polyphenylene ether resin, a polyoxymethylene resin, a polyester resin, It is at least one selected from the group consisting of polycarbonate resin, polystyrene resin, polyolefin resin, and polyamide.

  Moreover, the carbon fiber reinforced thermoplastic resin composition of the present invention is the sizing agent-coated carbon fiber obtained by adhering 0.1 to 10.0 parts by mass of the sizing agent to 100 parts by mass of the carbon fiber in the above invention. It consists of 1 to 80% by mass and 20 to 99% by mass of the thermoplastic resin (G).

  Moreover, the carbon fiber reinforced thermoplastic resin composition of the present invention is a sizing agent coating obtained by attaching 0.1 to 10.0 parts by mass of the sizing agent to 100 parts by mass of the carbon fiber in the above invention. It is obtained by melt-kneading 1 to 80% by mass of carbon fiber and 20 to 99% by mass of thermoplastic resin (G).

  Moreover, the carbon fiber reinforced composite material of the present invention is formed by molding the prepreg according to any one of the above or a carbon fiber reinforced thermoplastic resin composition.

  According to the present invention, it is possible to obtain a sizing agent-coated carbon fiber that has excellent adhesion to a matrix resin and is excellent in convergence and smoothness. Further, by applying the sizing agent-coated carbon fiber, a prepreg or a carbon fiber reinforced thermoplastic resin composition for obtaining a carbon fiber reinforced composite material having excellent physical properties can be obtained.

  Hereinafter, the form for enforcing the manufacturing method of the sizing agent application | coating carbon fiber of this invention and the sizing agent application | coating carbon fiber of this invention is demonstrated.

The present invention, at least (A) ~ a carbon fiber coated with a sizing agent comprising (C), the C _1s inner shell spectrum measured by X-ray photoelectron spectroscopy sizing agent surface photoelectron escape angle 15 ° (A) the height (cps) of the component of the bond energy (284.6 eV) attributed to CHx, C—C, C = C and (b) the bond energy (286.1 eV) attributed to C—O The component height (cps) ratio (a) / (b) is 0.50 to 0.90.
(A) Aliphatic epoxy compound (B) Condensate of unsaturated dibasic acid and alkylene oxide adduct of bisphenols (C) Nonionic surfactant containing an aromatic ring.

  In the following description, (B) a condensate of an unsaturated dibasic acid and an alkylene oxide adduct of bisphenols is referred to as “condensate (B)”, and (C) a nonionic surfactant containing an aromatic ring. It may be abbreviated as “nonionic surfactant (C)”.

  According to the knowledge of the present inventors, those in such a range are excellent in interfacial adhesion between the carbon fiber and the matrix resin, and have high convergence and smoothness. Therefore, the sizing agent-coated carbon fiber is used as a prepreg or Even when used in a thermoplastic resin composition, a carbon fiber reinforced composite material having high processability and good physical properties can be obtained.

  First, the sizing agent used in the present invention will be described. The sizing agent according to the present invention contains at least (A) to (C).

  When the sizing agent according to the present invention is applied to carbon fibers, a large amount of the aliphatic epoxy compound (A) is present inside the sizing layer (carbon fiber side), so that the carbon fiber and the aliphatic epoxy compound (A) are present. While strongly interacting and improving adhesion, the sizing layer surface layer (matrix resin side) contains a large amount of condensate (B), so that the sizing agent-coated carbon fiber has good adhesion and good convergence. Has smoothness.

  The sizing agent comprises only the condensate (B) and the nonionic surfactant (C), or the condensate (B), the nonionic surfactant (C) and the aromatic epoxy compound, and the aliphatic epoxy compound ( When A) is not included, it is confirmed that the adhesion between the carbon fiber and the matrix resin is inferior.

  Further, when the sizing agent is composed only of the aliphatic epoxy compound (A), it has been confirmed that the carbon fiber coated with the sizing agent has high adhesiveness with the matrix resin. Although the mechanism is not certain, the aliphatic epoxy compound (A) is derived from a flexible skeleton and a structure having a high degree of freedom, and the functional group of the carbon fiber surface with a carboxyl group and a hydroxyl group and the aliphatic epoxy compound (A) Are thought to be capable of forming strong interactions. However, there has been a problem that it is not sufficient in applications requiring high convergence and smoothness.

  In the present invention, when the aliphatic epoxy compound (A), the condensate (B), and the nonionic surfactant (C) are mixed, the aliphatic epoxy compound (A) having higher polarity is unevenly distributed on the carbon fiber side. And the phenomenon that the condensate (B) with low polarity tends to be unevenly distributed in the outermost layer of the sizing layer on the opposite side to the carbon fiber is observed. Further, the gradient structure of the sizing agent is stabilized by the nonionic surfactant (C). As a result of the inclined structure of the sizing layer, the aliphatic epoxy compound (A) has a strong interaction with the carbon fiber in the vicinity of the carbon fiber, and can improve the adhesion between the carbon fiber and the matrix resin. In addition, since a large amount of the condensate (B) is present in the outer layer, the sizing agent-coated carbon fiber has improved bundling and smoothness, and when the carbon fiber is used in a prepreg or carbon fiber reinforced thermoplastic resin composition, A carbon fiber reinforced composite material having good processability and high quality can be obtained.

  In addition, when the aliphatic epoxy compound (A) is almost completely covered with the condensate (B) and the nonionic surfactant (C), the interaction between the sizing agent and the matrix resin is reduced and the adhesiveness is lowered. In addition, since the physical properties of the obtained carbon fiber reinforced composite material are lowered, the abundance ratio of the aliphatic epoxy compound (A), condensate (B), and nonionic surfactant (C) on the surface of the sizing agent is important. It is.

  In the present invention, the sizing agent contains at least the aliphatic epoxy compound (A). The aliphatic epoxy compound (A) is an epoxy compound that does not contain an aromatic ring, and has an epoxy value of 2.0 to 8.0 meq / g and a hydroxyl value of 2.0 to 5.0 meq / g. It is preferable to have two or more epoxy groups.

  Since it has a flexible skeleton with a high degree of freedom, it can have a strong interaction with carbon fibers. As a result, the adhesion between the carbon fiber coated with the sizing agent and the matrix resin is improved.

  The epoxy value of the aliphatic epoxy compound (A) in the present invention is preferably 2.0 to 8.0 meq / g. When the epoxy value of the aliphatic epoxy compound (A) is 2.0 meq / g or more, an interaction with the carbon fiber is formed at a high density, and the adhesion between the carbon fiber and the matrix resin is further improved. An epoxy value of 8.0 meq / g or less is sufficient from the viewpoint of adhesiveness. The epoxy value of the aliphatic epoxy compound (A) is preferably 3.0 meq / g or more, and preferably 7.0 meq / g or less.

  The epoxy value of the aliphatic epoxy compound (A) in the present invention is determined by dissolving the aliphatic epoxy compound (A) in a solvent represented by N, N-dimethylformamide, opening the epoxy group with hydrochloric acid, Can be determined by titration.

  In the present invention, the aliphatic epoxy compound (A) preferably has two or more epoxy groups in the molecule. As a result, a strong bond between the carbon fiber and the epoxy group in the sizing agent can be formed. The number of epoxy groups in the molecule is more preferably 3 or more. When the water-soluble epoxy compound (A) is an epoxy compound having two or more epoxy groups in the molecule, even if one epoxy group forms a covalent bond with an oxygen-containing functional group on the surface of the carbon fiber, it remains The epoxy group can form a covalent bond or a hydrogen bond with the matrix resin, and the adhesiveness becomes high. There is no particular upper limit on the number of epoxy groups, but 10 is sufficient from the viewpoint of adhesion.

  The number of epoxy groups in the molecule of the aliphatic epoxy compound (A) in the present invention can be determined by dividing the epoxy equivalent calculated from the epoxy value by the number average molecular weight. The number average molecular weight can be determined by gel permeation chromatography (GPC) using dimethylformamide (0.01 N-lithium bromide added) as a solvent as a monodisperse polystyrene standard.

  In the present invention, the aliphatic epoxy compound (A) preferably has a hydroxyl group having a hydroxyl value of 2.0 to 5.0 meq / g. When the hydroxyl group is 2.0 meq / g or more, the interaction with polar groups such as hydroxyl groups and carboxyl groups on the surface of the carbon fiber is increased, and the aliphatic epoxy compound (A) is likely to be unevenly distributed inside the sizing layer. Rise. 2.5 meq / g or more is more preferable. When the hydroxyl value is 5.0 meq / g or less, hydrogen bonding between the aliphatic epoxy compounds (A) is suppressed, the viscosity is lowered, and the handleability is improved. Moreover, since an epoxy compound is manufactured by condensing epichlorohydrin with respect to a hydroxyl group, an epoxy value will improve relatively that a hydroxyl value is 5.0 meq or less, and carbon fiber and The adhesiveness of the matrix resin is improved. The hydroxyl value of the aliphatic epoxy compound (A) is more preferably 4.0 meq / g or less.

  The hydroxyl value of the aliphatic epoxy compound (A) in the present invention is determined by dissolving the aliphatic epoxy compound (A) in N, N-dimethylformamide, acetylating the hydroxyl group using acetic anhydride, and hydroxylating the resulting acetic acid. It can be determined by titrating with a potassium solution and correcting with the epoxy value.

  In the aliphatic epoxy compound (A) of the present invention, the hydroxyl value, the epoxy value, and the number of epoxy groups in one molecule select the molecular structure of the aliphatic epoxy compound, or the aliphatic epoxy compound is hydrolyzed or water is present. It can be controlled by heating in the absence.

  The aliphatic epoxy compound (A) of the present invention preferably has a functional group other than the above-described epoxy group and hydroxyl group. The functional group possessed by the aliphatic epoxy compound (A) is preferably selected from an amide group, an imide group, a urethane group, a urea group, a sulfonyl group, or a sulfo group in addition to the epoxy group and the hydroxyl group. When the aliphatic epoxy compound (A) is an epoxy compound having another functional group, even if the epoxy group forms a covalent bond or a hydrogen bond with the oxygen-containing functional group on the surface of the carbon fiber, the other functional group is a matrix. A covalent bond or a hydrogen bond can be formed with the resin, which is preferable because the adhesiveness is further improved. The number of functional groups including an epoxy group is preferably 3 or more in one molecule, and there is no particular upper limit, but 10 is sufficient from the viewpoint of adhesiveness.

  In the present invention, specific examples of the aliphatic epoxy compound (A) include, for example, a glycidyl ether type epoxy compound derived from a polyol, a glycidyl amine type epoxy compound derived from an amine having a plurality of active hydrogens, and a polycarboxylic acid. Examples thereof include an induced glycidyl ester type epoxy compound and an epoxy compound obtained by oxidizing a compound having a plurality of double bonds in the molecule.

  Examples of the glycidyl ether type epoxy compound include a glycidyl ether type epoxy compound obtained by a reaction between a polyol and epichlorohydrin. For example, as a glycidyl ether type epoxy compound, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, polypropylene glycol, trimethylene glycol, 1, 2 -Butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, polybutylene glycol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,4 -Cyclohexanedimethanol, hydrogenated bisphenol A, hydrogenated bisphenol F, glycerol, diglycerol, polyglycerol, trimethylolpropane, Pentaerythritol, sorbitol, and one and selected from arabitol, glycidyl ether type epoxy compound obtained by reaction with epichlorohydrin. Examples of the glycidyl ether type epoxy compound include a glycidyl ether type epoxy compound having a dicyclopentadiene skeleton.

  Examples of the glycidylamine type epoxy compound include 1,3-bis (aminomethyl) cyclohexane.

  Examples of the glycidyl ester type epoxy compound include a glycidyl ester type epoxy compound obtained by reacting dimer acid with epichlorohydrin.

  Examples of the epoxy compound obtained by oxidizing a compound having a plurality of double bonds in the molecule include an epoxy compound having an epoxycyclohexane ring in the molecule. Furthermore, the epoxy compound includes epoxidized soybean oil.

  Examples of the aliphatic epoxy compound (A) used in the present invention include epoxy compounds such as triglycidyl isocyanurate in addition to these epoxy compounds.

  Examples of the aliphatic epoxy compound (A) include sorbitol type polyglycidyl ether and glycerol type polyglycidyl ether. Specifically, “Denacol (registered trademark)” EX-611, EX-612, EX-614. , EX-614B, EX-622, EX-512, EX-521, EX-421, EX-313, EX-314 and EX-321 (manufactured by Nagase ChemteX Corporation).

  Examples of the aliphatic epoxy compound (A) having an amide group in addition to the epoxy group include an amide-modified epoxy compound. The amide-modified epoxy can be obtained by reacting an epoxy group of an epoxy compound having two or more epoxy groups with a carboxyl group of an aliphatic dicarboxylic acid amide.

  Examples of the aliphatic epoxy compound (A) having a urethane group in addition to the epoxy group include a urethane-modified epoxy compound. Specifically, “Adeka Resin (registered trademark)” EPU-78-13S, EPU-6, EPU-11, EPU-15, EPU-16A, EPU-16N, EPU-17T-6, EPU-1348, EPU-1395 (manufactured by ADEKA Corporation) and the like can be mentioned. Alternatively, by reacting the terminal hydroxyl group of the polyethylene oxide monoalkyl ether with a polyvalent isocyanate equivalent to the amount of the hydroxyl group, and then reacting the isocyanate residue of the obtained reaction product with the hydroxyl group in the polyvalent epoxy compound. Can be obtained. Here, examples of the polyvalent isocyanate used include hexamethylene diisocyanate, isophorone diisocyanate, and norbornane diisocyanate.

  Examples of the aliphatic epoxy compound (A) having a urea group in addition to the epoxy group include a urea-modified epoxy compound. The urea-modified epoxy compound can be obtained by reacting the epoxy group of an epoxy compound having two or more epoxy groups with the carboxyl group of the aliphatic dicarboxylic acid urea.

  The aliphatic epoxy compound (A) used in the present invention includes one selected from glycerol, diglycerol, polyglycerol, trimethylolpropane, pentaerythritol, sorbitol, and arabitol from the viewpoint of high adhesion among the above, A glycidyl ether type epoxy compound obtained by reaction with chlorohydrin is more preferred.

  In the present invention, the aliphatic epoxy compound (A) is more preferably polyglycerol polyglycidyl ether.

  The sizing agent of the present invention contains at least a condensate (B) of an unsaturated dibasic acid and an alkylene oxide adduct of bisphenols.

  The condensate (B) tends to form an inclined structure with the aliphatic epoxy compound (A), and the condensate (B) present on the outside improves the sizing agent-coated carbon fibers in terms of convergence and smoothness.

  Examples of the unsaturated dibasic acid include fumaric acid, maleic acid, citraconic acid, itaconic acid and the like. Examples of the alkylene oxide adduct of bisphenols include alkylene oxides of bisphenols. Examples of the alkylene oxide include ethylene oxide, propylene oxide, and butylene oxide. Two or more types of alkylene oxide adducts may be used, and either a block copolymer or a random copolymer may be used.

  Most preferred is a condensate of fumaric acid or maleic acid with an ethylene oxide or propylene oxide adduct of bisphenol A. The addition method of alkylene oxide may be a conventional method, and the number of moles added is 1 to 100, preferably 1 to 20, particularly preferably 1 to 5. If necessary, the unsaturated dibasic acid is partially saturated dibasic acid or a small amount of monobasic acid, and the alkylene oxide adducts of bisphenols are ordinary glycol, polyether glycol and a small amount of polyhydric alcohol. Monohydric alcohol and the like can be added as long as the physical properties are not impaired. The condensation method of the unsaturated dibasic acid and the alkylene oxide adduct of bisphenols may be a conventional method. The molar ratio of the unsaturated dibasic acid (a) to the alkylene oxide adduct (b) of bisphenols is preferably (a) :( b) = 0.8 to 1.2: 1.2 to 0.8. , More preferably 1: 1. The softening point of the condensate is preferably 40 to 80 ° C.

  The sizing agent of the present invention contains at least a nonionic surfactant (C) containing an aromatic ring. The aromatic ring may be an aromatic ring hydrocarbon consisting only of carbon, or a heteroaromatic ring such as furan, thiophene, pyrrole or imidazole containing a heteroatom such as nitrogen or oxygen. The aromatic ring may be a polycyclic aromatic ring such as naphthalene or anthracene.

  The nonionic surfactant of the present invention is preferably an alkylene oxide adduct of phenols. Phenols are monocyclic phenols having one aromatic ring in the molecule or polycyclic phenols having two or more aromatic rings in the molecule. Examples of the monocyclic phenol include phenol, phenol having one or more alkyl groups, and polyhydric phenol.

  Examples of the polycyclic phenol having two or more aromatic rings in the molecule include phenylphenol, cumylphenol, benzylphenol, hydroquinone monophenyl ether, naphthol, and bisphenol. Moreover, the reaction product of monocyclic phenol or polycyclic phenol and styrenes may be used.

  Examples of the alkylene oxide include ethylene oxide, propylene oxide, and butylene oxide. Two or more types of alkylene oxide adducts may be used, and either a block copolymer or a random copolymer may be used. Most preferred are ethylene oxide adducts of styrenated phenols or ethylene oxide and propylene oxide adducts. The method of adding alkylene oxide to phenols may be a conventional method and is not limited. The number of moles of alkylene oxide to be added is usually 1 to 120, preferably 10 to 90, particularly preferably 30 to 80.

  The sizing agent according to the present invention preferably contains at least 35 to 65% by mass of the aliphatic epoxy compound (A) and 35 to 60% by mass of the condensate (B) with respect to the total amount of the sizing agent excluding the solvent. Adhesiveness improves by mix | blending an aliphatic epoxy compound (A) with 35 mass% or more with respect to the sizing agent whole quantity except a solvent. Moreover, by setting it as 65 mass% or less, components other than an aliphatic epoxy compound (A) can be used as a sizing agent, the prepreg manufactured using the said sizing agent application | coating carbon fiber, a carbon fiber reinforced thermoplastic resin The quality of the carbon fiber reinforced composite material made of is improved. As for the compounding quantity of an aliphatic epoxy compound (A), 38 mass% or more is more preferable, and 40 mass% or more is further more preferable. Further, the blending amount of the aliphatic epoxy compound (A) is more preferably 60% by mass or less, and further preferably 55% by mass or more.

  In the sizing agent of the present invention, the composition of the condensate (B) in the outer layer of the sizing agent is maintained high by blending the condensate (B) in an amount of 35% by mass or more based on the total amount of the sizing agent excluding the solvent. Therefore, it is preferable because the sizing agent-coated carbon fiber has improved bundling properties and smoothness, and the resulting prepreg and carbon fiber reinforced composite material composed of carbon fiber reinforced thermoplastic resin are improved in quality. The blending amount of the condensate (B) is more preferably 37% by mass or more, and further preferably 39% by mass or more. Moreover, 55 mass% or less is more preferable, and, as for the compounding quantity of a condensate (B), 45 mass% or less is further more preferable.

  The mass ratio (A) / (B) of the aliphatic epoxy compound (A) and the condensate (B) in the sizing agent in the present invention is preferably 52/48 to 80/20. By setting (A) / (B) to 52/48 or more, the ratio of the aliphatic epoxy compound (A) present on the carbon fiber surface is increased, and the adhesion between the carbon fiber and the matrix resin is improved. As a result, the composite properties of the obtained carbon fiber reinforced composite material are improved. Moreover, by making (A) / (B) 80/20 or less, the abundance ratio of the condensate (B) present in the sizing agent surface layer is increased, and the convergence and smoothness of the sizing agent-coated carbon fibers are improved. . The mass ratio of (A) / (B) is more preferably 55/45 or more. The mass ratio of (A) / (B) is more preferably 75/35 or less, and further preferably 73/37 or less.

  Furthermore, the sizing agent used in the present invention may contain one or more components other than the aliphatic epoxy compound (A), the condensate (B), and the nonionic surfactant (C). Examples thereof include an epoxy compound other than the aliphatic epoxy compound (A), an ester compound other than the condensate (B), and an adhesion promoting component that enhances the adhesion between the carbon fiber and the sizing agent. For the purpose of stabilizing the sizing agent, auxiliary components such as a dispersant and a surfactant may be added.

  In this invention, an aromatic epoxy compound (D) can be included. An aromatic epoxy compound is an epoxy compound having one or more aromatic rings in the molecule. The aromatic ring may be an aromatic ring hydrocarbon consisting only of carbon, or a heteroaromatic ring such as furan, thiophene, pyrrole or imidazole containing a heteroatom such as nitrogen or oxygen. The aromatic ring may be a polycyclic aromatic ring such as naphthalene or anthracene. Having an aromatic ring is preferable because the polarity is low and a large amount can be present in the outer layer of the sizing agent, and the convergence and smoothness of the sizing agent-coated carbon fibers are improved. The number of aromatic rings is preferably 2 or more in the molecule. There is no particular upper limit on the number of aromatic rings, but 10 is sufficient from the standpoint of mechanical properties.

  In the present invention, the aromatic epoxy compound (D) has one or more epoxy groups in the molecule. By having an epoxy group, the amount of the epoxy group contained in the sizing agent is increased, which is preferable because the adhesiveness is increased. In the present invention, the number of epoxy groups of the aromatic epoxy compound (D) is preferably 2 or more, and more preferably 3 or more. Moreover, it is preferable that it is 10 or less from a polar viewpoint.

  In addition to the epoxy group, it preferably has a functional group selected from a hydroxyl group, an amide group, an imide group, a urethane group, a urea group, a sulfonyl group, a carboxyl group, an ester group or a sulfo group. In addition to the epoxy group, two or more functional groups may be included in one molecule.

  In the present invention, the aromatic epoxy compound (D) has an epoxy value of 2.8 meq. / G, more preferably 3.7 meq. / G, more preferably 5.3 meq. It is a value larger than / g. The epoxy value of the aromatic epoxy compound (D) is 2.8 meq. When it is larger than / g, covalent bonds are formed at a high density, and the adhesion between the carbon fibers and the matrix resin is further improved. Although there is no lower limit of the epoxy value, 11.0 meq. / G or less is sufficient from the viewpoint of adhesiveness.

  In the present invention, specific examples of the aromatic epoxy compound (D) include, for example, a glycidyl ether type epoxy compound derived from an aromatic polyol, a glycidyl amine type epoxy compound derived from an aromatic amine having a plurality of active hydrogens, Examples thereof include glycidyl ester type epoxy compounds derived from aromatic polycarboxylic acids, and epoxy compounds obtained by oxidizing aromatic compounds having a plurality of double bonds in the molecule.

  Examples of the glycidyl ether type epoxy compound include bisphenol A, bisphenol F, bisphenol AD, bisphenol S, tetrabromobisphenol A, phenol novolac, cresol novolac, hydroquinone, resorcinol, 4,4′-dihydroxy-3,3 ′, 5. , 5′-tetramethylbiphenyl, 1,6-dihydroxynaphthalene, 9,9-bis (4-hydroxyphenyl) fluorene, tris (p-hydroxyphenyl) methane, and tetrakis (p-hydroxyphenyl) ethane The glycidyl ether type epoxy compound obtained by reaction with 1 type and epichlorohydrin is mentioned. Examples of the glycidyl ether type epoxy compound include a glycidyl ether type epoxy compound having a biphenylaralkyl skeleton.

  Examples of the glycidylamine type epoxy compound include N, N-diglycidylaniline, N, N-diglycidyl-o-toluidine, m-xylylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane and 9 , 9-bis (4-aminophenyl) fluorene, and a glycidyl ether type epoxy compound obtained by reaction with epichlorohydrin.

  Further, for example, as a glycidylamine type epoxy compound, both the hydroxyl group and amino group of aminophenols of m-aminophenol, p-aminophenol, and 4-amino-3-methylphenol are reacted with epichlorohydrin. And an epoxy compound obtained.

  Examples of the glycidyl ester type epoxy compound include glycidyl ester type epoxy compounds obtained by reacting phthalic acid, terephthalic acid, and hexahydrophthalic acid with epichlorohydrin.

  As the aromatic epoxy compound (D) used in the present invention, in addition to these epoxy compounds, epoxy compounds synthesized from the above-mentioned epoxy compounds, for example, oxazolidone from bisphenol A diglycidyl ether and tolylene diisocyanate An epoxy compound synthesized by a ring formation reaction is exemplified.

  In the present invention, the aromatic epoxy compound (D) is preferably either a phenol novolac epoxy compound, a cresol novolac epoxy compound, or tetraglycidyl diaminodiphenylmethane. These epoxy compounds have a large number of epoxy groups, a large epoxy value, and two or more aromatic rings, and improve the adhesion between the carbon fiber and the matrix resin.

  In the present invention, the aromatic epoxy compound (D) is preferably a phenol novolac type epoxy compound, a cresol novolac type epoxy compound, tetraglycidyl diaminodiphenylmethane, a bisphenol A type epoxy compound or a bisphenol F type epoxy compound, and a bisphenol A type. An epoxy compound or a bisphenol F type epoxy compound is more preferable.

  In the sizing agent used in the present invention, an ester compound other than the condensate (B) can be blended. By blending the ester compound, the convergence can be improved and the handleability can be improved. It may be an aliphatic ester compound having no aromatic ring or an aromatic ester compound other than the condensate (B) having one or more aromatic rings in the molecule. In addition to the ester group, the ester compound of the present invention has a functional group other than an epoxy group, such as a hydroxyl group, an amide group, an imide group, a urethane group, a urea group, a sulfonyl group, a carboxyl group, and a sulfo group. It may be.

  Next, the carbon fiber used in the present invention will be described. Examples of the carbon fiber used in the present invention include polyacrylonitrile (PAN) -based, rayon-based, and pitch-based carbon fibers. Of these, PAN-based carbon fibers having an excellent balance between strength and elastic modulus are preferably used.

  In the carbon fiber according to the present invention, the strand strength of the obtained carbon fiber bundle is preferably 3.5 GPa or more, more preferably 4 GPa or more, and further preferably 5 GPa or more. Moreover, it is preferable that the strand elastic modulus of the obtained carbon fiber bundle is 220 GPa or more, More preferably, it is 240 GPa or more, More preferably, it is 280 GPa or more.

  In the present invention, the strand tensile strength and elastic modulus of the carbon fiber bundle can be determined according to the following procedure in accordance with the resin impregnated strand test method of JIS-R-7608 (2004). As the resin formulation, “Celoxide (registered trademark)” 2021P (manufactured by Daicel Chemical Industries) / 3 boron trifluoride monoethylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) / Acetone = 100/3/4 (part by mass) is used. As curing conditions, normal pressure, 130 ° C., and 30 minutes are used. Ten strands of the carbon fiber bundle were measured, and the average value was defined as the strand tensile strength and the strand elastic modulus.

  The carbon fiber used in the present invention preferably has a surface roughness (Ra) of 6.0 to 100 nm. More preferably, it is 15-80 nm, and 30-60 nm is suitable. Carbon fiber with a surface roughness (Ra) of 6.0 to 60 nm has a highly active edge portion on the surface, so the reactivity with the epoxy group of the sizing agent described above is improved and the interfacial adhesion is improved. This is preferable. Moreover, since the carbon fiber whose surface roughness (Ra) is 6.0-100 nm has an unevenness | corrugation on the surface, it can improve interface adhesiveness by the anchor effect of a sizing agent, and is preferable.

The average roughness (Ra) of the carbon fiber surface can be measured by using an atomic force microscope (AFM). For example, a carbon fiber cut to several millimeters in length is prepared, fixed on a substrate (silicon wafer) using a silver paste, and 3 atomic fibers at the center of each single fiber by an atomic force microscope (AFM). What is necessary is just to observe the image of a three-dimensional surface shape. As an atomic force microscope, a Dimension 3000 stage system or the like can be used in NanoScope IIIa manufactured by Digital Instruments and can be observed under the following observation conditions.
・ Scanning mode: Tapping mode ・ Probe: Silicon cantilever ・ Scanning range: 0.6μm × 0.6μm
・ Scanning speed: 0.3Hz
-Number of pixels: 512 × 512
・ Measurement environment: Room temperature, in air.

  In addition, for each sample, an image obtained by observing one single fiber from one point at a time approximates the roundness of the fiber cross section with a cubic surface, and the average roughness (Ra) for the entire image obtained. It is preferable to calculate the average roughness (Ra) and evaluate the average value for five single fibers.

  In the present invention, the total fineness of the carbon fibers is preferably 400 to 3000 tex. Moreover, the number of filaments of carbon fiber is preferably 1000 to 100,000, and more preferably 3000 to 50000.

  In the present invention, the single fiber diameter of the carbon fiber is preferably 4.5 to 7.5 μm. Since it is 7.5 micrometers or less, since a carbon fiber with high intensity | strength and elastic modulus can be obtained, it is used preferably. More preferably, it is 6 μm or less, and further preferably 5.5 μm or less. When the thickness is 4.5 μm or more, it is difficult to cause single fiber cutting in the process, and productivity is hardly lowered.

  In the present invention, the carbon fiber has a surface oxygen concentration (O / C), which is a ratio of the number of atoms of oxygen (O) and carbon (C) on the fiber surface measured by X-ray photoelectron spectroscopy. The thing within the range of 05-0.50 is preferable, More preferably, it is a thing within the range of 0.06-0.30, More preferably, it is a thing within the range of 0.07-0.25. When the surface oxygen concentration (O / C) is 0.05 or more, an oxygen-containing functional group on the surface of the carbon fiber can be secured and strong adhesion with the matrix resin can be obtained. Moreover, when the surface oxygen concentration (O / C) is 0.50 or less, a decrease in strength of the carbon fiber itself due to oxidation can be suppressed.

The surface oxygen concentration of the carbon fiber is determined by X-ray photoelectron spectroscopy according to the following procedure. First, carbon fibers from which dirt and the like adhering to the carbon fiber surface were removed with a solvent were cut to 20 mm, spread and arranged on a copper sample support base, and then AlKα ₁ and ₂ were used as an X-ray source. The inside of the chamber was measured at 1 × 10 ⁻⁸ Torr. Measurement was performed at a photoelectron escape angle of 90 °. As a correction value for the peak accompanying charging during measurement, the binding energy value of the C _1s main peak (peak top) is adjusted to 284.6 eV. The C _1s peak area is obtained by drawing a straight base line in the range of 282 to 296 eV, and the O _1s peak area is obtained by drawing a straight base line in the range of 528 to 540 eV. The surface oxygen concentration (O / C) is represented by an atomic ratio calculated by dividing the ratio of the O _1s peak area by the sensitivity correction value unique to the apparatus. When ESCA-1600 manufactured by ULVAC-PHI Co., Ltd. is used as the X-ray photoelectron spectroscopy apparatus, the sensitivity correction value unique to the apparatus is 2.33.

  The carbon fiber used in the present invention has a surface carboxyl group concentration (COOH / C) represented by the ratio of the number of carbon group (COOH) and carbon (C) atoms measured by chemical modification X-ray photoelectron spectroscopy. ) Is preferably in the range of 0.003 to 0.015. A more preferable range of the carboxyl group concentration (COOH / C) on the carbon fiber surface is 0.004 to 0.010. The carbon fiber used in the present invention has a surface hydroxyl group concentration (COH / C) expressed by the ratio of the number of hydroxyl groups (OH) and carbon (C) on the surface of the carbon fiber measured by chemical modification X-ray photoelectron spectroscopy. ) Is preferably in the range of 0.001 to 0.050. The surface hydroxyl group concentration (COH / C) on the carbon fiber surface is more preferably in the range of 0.010 to 0.040.

  The surface carboxyl group concentration (COOH / C) and hydroxyl group concentration (COH / C) of the carbon fiber are determined by X-ray photoelectron spectroscopy according to the following procedure.

The surface hydroxyl group concentration (COH / C) is determined by chemical modification X-ray photoelectron spectroscopy according to the following procedure. First, carbon fiber bundles from which the sizing agent and the like have been removed with a solvent are cut, spread and arranged on a platinum sample support, and placed in dry nitrogen gas containing 0.04 mol / liter of anhydrous trifluoride acetic acid gas. After 10 minutes of exposure at room temperature and chemical modification treatment, it was mounted on an X-ray photoelectron spectrometer with a photoelectron escape angle of 35 °, AlKα ₁ , ₂ was used as the X-ray source, and the inside of the sample chamber was 1 × 10 ⁻⁸ Torr. Keep the degree of vacuum. As correction of the peak accompanying charging during measurement, first, the binding energy value of the main peak of C _1s is adjusted to 284.6 eV. The C _1s peak area [C _1s ] is obtained by drawing a straight base line in the range of 282 to 296 eV, and the F _1s peak area [F _1s ] is obtained by drawing a straight base line in the range of 682 to 695 eV. Desired. Moreover, reaction rate r is calculated | required from _C1s peak division _| segmentation of the polyvinyl alcohol chemically modified simultaneously.

  The surface hydroxyl group concentration (COH / C) is represented by a value calculated by the following equation.

COH / C = {[F _1s ] / (3k [C _1s ] −2 [F _1s ]) r} × 100 (%)
Note that k is the sensitivity correction value of the F _1s peak area with respect to the C _1s peak area unique to the apparatus, and when using the model SSX-100-206 manufactured by SSI of the United States, the sensitivity correction value specific to the apparatus is 3.919. .

The surface carboxyl group concentration (COOH / C) is determined by chemical modification X-ray photoelectron spectroscopy according to the following procedure. First, carbon fiber bundles from which the sizing agent and the like have been removed with a solvent are cut and spread and arranged on a platinum sample support, and 0.02 mol / liter of trifluorinated ethanol gas, 0.001 mol / liter of dicyclohexyl. After exposure to air containing carbodiimide gas and 0.04 mol / liter pyridine gas at 60 ° C. for 8 hours and chemical modification treatment, it was mounted on an X-ray photoelectron spectrometer with a photoelectron escape angle of 35 ° as an X-ray source. Using AlKα ₁ and ₂ , the inside of the sample chamber is kept at a vacuum of 1 × 10 ⁻⁸ Torr. As correction of the peak accompanying charging during measurement, first, the binding energy value of the main peak of C _1s is adjusted to 284.6 eV. The C _1s peak area [C _1s ] is obtained by drawing a straight base line in the range of 282 to 296 eV, and the F _1s peak area [F _1s ] is obtained by drawing a straight base line in the range of 682 to 695 eV. Desired. Simultaneously, the reaction rate r is determined from the C _1s peak splitting of the polyacrylic acid chemically modified, and the residual rate m of the dicyclohexylcarbodiimide derivative is determined from the O _1s peak splitting.

  The surface carboxyl group concentration COOH / C was represented by the value calculated by the following formula.

COOH / C = {[F _1s ] / (3k [C _1s ] − (2 + 13 m) [F _1s ]) r} × 100 (%)
Note that k is the sensitivity correction value of the F _1s peak area with respect to the C _1s peak area unique to the apparatus, and the sensitivity correction value specific to the apparatus when using the model SSX-100-206 manufactured by SSI of the United States is 3.919. is there.

The carbon fibers used in the present invention, it is preferred polar component of the surface free energy is of 8 mJ / ^{m 2} or more 50 mJ / ^{m 2} or less. Since the polar component of the surface free energy is 8 mJ / m ² or more, the aliphatic epoxy compound (A) is closer to the carbon fiber surface, so that the adhesion is improved and the sizing layer is unevenly distributed. . When the polar component of the surface free energy is 50 mJ / m ² or less, the convergence property between the carbon fibers is increased, so that the impregnation property with the matrix resin is improved. When used as a carbon fiber reinforced composite material Applications are widespread and preferable.

Polar component of the surface free energy of the carbon fiber surface is more preferably 15 mJ / ^{m 2} or more 45 mJ / ^{m 2} or less, and most preferably 25 mJ / ^{m 2} or more 40 mJ / ^{m 2} or less. The polar component of the surface free energy of the carbon fiber was calculated using an Owens approximation formula based on the contact angles measured by the Wilhelmi method in each liquid of water, ethylene glycol, and tricresole phosphate. Polar component of surface free energy.

  Next, a method for producing a PAN-based carbon fiber will be described.

  As a spinning method for obtaining a carbon fiber precursor fiber, spinning methods such as wet, dry, and dry-wet can be used. From the viewpoint of easily obtaining high-strength carbon fibers, it is preferable to use a wet or dry wet spinning method. In particular, the use of a dry and wet spinning method is more preferable because carbon fibers having high strength can be obtained.

  In order to further improve the adhesion between the carbon fiber and the matrix resin, a carbon fiber having a surface roughness (Ra) of 6.0 to 100 nm is preferable. In order to obtain a carbon fiber having the surface roughness, a wet spinning method is used. Preferably, the precursor fiber is spun by.

  As the spinning dope, a solution obtained by dissolving a homopolymer or copolymer of polyacrylonitrile in a solvent can be used. As the solvent, an organic solvent such as dimethyl sulfoxide, dimethylformamide, or dimethylacetamide, or an aqueous solution of an inorganic compound such as nitric acid, sodium rhodanate, zinc chloride, or sodium thiocyanate is used. Dimethyl sulfoxide and dimethylacetamide are suitable as the solvent.

  The above spinning solution is spun through a die, discharged in a spinning bath or in the air, and then coagulated in the spinning bath. As the spinning bath, an aqueous solution of a solvent used as a solvent for the spinning dope can be used. It is preferable to use a spinning solution containing the same solvent as the spinning solution, and a dimethyl sulfoxide aqueous solution and a dimethylacetamide aqueous solution are preferable. The fiber solidified in the spinning bath is washed with water and drawn to obtain a precursor fiber. The obtained precursor fiber is subjected to flameproofing treatment and carbonization treatment, and if necessary, further subjected to graphitization treatment to obtain carbon fiber. As conditions for carbonization treatment and graphitization treatment, the maximum heat treatment temperature is preferably 1100 ° C. or higher, more preferably 1400 to 3000 ° C.

  The obtained carbon fiber is usually subjected to an oxidation treatment in order to improve the adhesiveness with the matrix resin, whereby oxygen-containing functional groups are introduced. As the oxidation treatment method, vapor phase oxidation, liquid phase oxidation, and liquid phase electrolytic oxidation are used. From the viewpoint of high productivity and uniform treatment, liquid phase electrolytic oxidation is preferably used.

  In the present invention, examples of the electrolytic solution used in the liquid phase electrolytic oxidation include an acidic electrolytic solution and an alkaline electrolytic solution. From the viewpoint of adhesion, a liquid phase electrolytic oxidation is performed in an alkaline electrolytic solution, and then a sizing agent is applied. It is more preferable.

  Examples of the acidic electrolyte include inorganic acids such as sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid, boric acid, and carbonic acid, organic acids such as acetic acid, butyric acid, oxalic acid, acrylic acid, and maleic acid, or ammonium sulfate and ammonium hydrogen sulfate. And the like. Of these, sulfuric acid and nitric acid exhibiting strong acidity are preferably used.

  Specific examples of the alkaline electrolyte include aqueous solutions of hydroxides such as sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide and barium hydroxide, sodium carbonate, potassium carbonate, magnesium carbonate, calcium carbonate, Aqueous solutions of carbonates such as barium carbonate and ammonium carbonate, aqueous solutions of bicarbonates such as sodium bicarbonate, potassium bicarbonate, magnesium bicarbonate, calcium bicarbonate, barium bicarbonate and ammonium bicarbonate, ammonia, tetraalkylammonium hydroxide And an aqueous solution of hydrazine. Among these, from the viewpoint of not containing an alkali metal that causes curing inhibition of the matrix resin, an aqueous solution of ammonium carbonate and ammonium hydrogen carbonate or an aqueous solution of tetraalkylammonium hydroxide exhibiting strong alkalinity is preferably used.

  The concentration of the electrolytic solution used in the present invention is preferably in the range of 0.01 to 5 mol / L, more preferably in the range of 0.1 to 1 mol / L. When the concentration of the electrolytic solution is 0.01 mol / L or more, the electrolytic treatment voltage is lowered, which is advantageous in terms of operating cost. On the other hand, when the concentration of the electrolytic solution is 5 mol / L or less, it is advantageous from the viewpoint of safety.

  The temperature of the electrolytic solution used in the present invention is preferably in the range of 10 to 100 ° C, more preferably in the range of 10 to 40 ° C. When the temperature of the electrolytic solution is 10 ° C. or higher, the efficiency of the electrolytic treatment is improved, which is advantageous in terms of operating cost. On the other hand, when the temperature of the electrolytic solution is less than 100 ° C., it is advantageous from the viewpoint of safety.

  In the present invention, the amount of electricity in the liquid phase electrolytic oxidation is preferably optimized in accordance with the carbonization degree of the carbon fiber, and a larger amount of electricity is required when processing the carbon fiber having a high elastic modulus.

In the present invention, the current density in the liquid phase electrolytic oxidation is preferably in the range of 1.5 to 1000 amperes / m ² per 1 m ² of the surface area of the carbon fiber in the electrolytic treatment solution, more preferably 3 to 500 amperes. / M ² within the range. When the current density is 1.5 amperes / m ² or more, the efficiency of the electrolytic treatment is improved, which is advantageous in terms of operating cost. On the other hand, when the current density is 1000 amperes / m ² or less, it is advantageous from the viewpoint of safety.

  In the present invention, it is preferable to wash and dry the carbon fiber after the electrolytic treatment. As a cleaning method, for example, a dip method or a spray method can be used. Especially, it is preferable to use a dip method from a viewpoint that washing | cleaning is easy, Furthermore, it is a preferable aspect to use a dip method, vibrating a carbon fiber with an ultrasonic wave. Also, if the drying temperature is too high, the functional groups present on the outermost surface of the carbon fiber are likely to disappear due to thermal decomposition, so it is desirable to dry at the lowest possible temperature. Specifically, the drying temperature is preferably 250 ° C. or lower. More preferably, drying is performed at 210 ° C. or lower. On the other hand, considering the efficiency of drying, the drying temperature is preferably 110 ° C. or higher, and more preferably 140 ° C. or higher.

  Next, the manufacturing method of the sizing agent application | coating carbon fiber which apply | coated the sizing agent to the carbon fiber mentioned above is demonstrated.

  The sizing agent-coated carbon fiber of the present invention comprises at least the above-described carbon fiber and at least the above-described aliphatic epoxy compound (A), the above-mentioned condensate (B), and the above-described nonionic surfactant (C). It is preferable to apply an agent. The carbon fiber is preferably applied with a sizing agent-containing liquid after being oxidized in an alkaline electrolytic solution from the liquid phase electrolytic oxidation described above.

  The sizing agent according to the present invention includes at least the above-described aliphatic epoxy compound (A), the above-described condensate (B), and the above-described nonionic surfactant (C), and may include other components. .

  In the present invention, as a method for applying a sizing agent to carbon fibers, an aliphatic epoxy compound (A) condensate (B), a nonionic surfactant (C) and other components are simultaneously dissolved or dispersed in a solvent. Using a sizing agent-containing liquid, a method of applying at once, each compound (A), (B), (C) and other components are arbitrarily selected and individually sizing agent-containing liquids dissolved or dispersed in a solvent A method of applying to carbon fiber in a plurality of times is preferably used. In the present invention, it is possible to obtain a sizing layer outer layer which is an object of the present invention by adopting a one-step application in which a sizing agent-containing liquid containing all components of a sizing agent is applied to carbon fibers at one time. It is more preferably used because of its ease of processing.

  The sizing agent according to the present invention can be used as a sizing agent-containing liquid obtained by diluting a sizing agent component with a solvent. Examples of such a solvent include water, methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, dimethylformamide, and dimethylacetamide. Among them, handling is easy and advantageous from the viewpoint of safety. Therefore, an aqueous dispersion or aqueous solution emulsified with a surfactant is preferably used.

  In the present invention, it is preferable to apply to the carbon fiber a sizing agent-containing liquid obtained by mixing a water emulsion liquid containing at least the condensate (B) and a composition containing at least the aliphatic epoxy compound (A).

  The sizing agent-containing liquid is a solution containing at least an aliphatic epoxy compound (A) by creating a water emulsion liquid by emulsifying a component containing at least the condensate (B) with a nonionic surfactant (C). It is preferable to adjust by mixing. At this time, when the aliphatic epoxy compound (A) is water-soluble, a method of dissolving in water in advance to form an aqueous solution and mixing with an aqueous emulsion liquid containing at least the aromatic compound (B) is an emulsion stability. It is preferably used from the viewpoint of

  The concentration of the sizing agent in the sizing agent-containing liquid is usually preferably in the range of 0.2% by mass to 20% by mass.

  Examples of the means for applying (coating) the sizing agent to the carbon fiber include a method of immersing the carbon fiber in a sizing agent-containing liquid through a roller, a method of contacting the carbon fiber with a roller to which the sizing agent-containing liquid is attached, and a sizing agent. There is a method of spraying the liquid on the carbon fiber in the form of a mist. Further, the sizing agent applying means may be either a batch type or a continuous type, but a continuous type capable of improving productivity and reducing variation is preferably used. At this time, it is preferable to control the concentration of the sizing agent-containing liquid, the temperature, the yarn tension, and the like so that the amount of the sizing agent active component attached to the carbon fiber is uniformly attached within an appropriate range. Moreover, it is also a preferable aspect that the carbon fiber is vibrated with ultrasonic waves when the sizing agent is applied.

  The liquid temperature of the sizing agent-containing liquid when the sizing liquid is applied to the carbon fiber is preferably in the range of 10 to 50 ° C. in order to suppress fluctuations in the concentration of the sizing agent due to solvent evaporation. In addition, after applying the sizing agent-containing liquid, the amount of sizing agent adhered can be adjusted and uniformly applied to the carbon fiber by adjusting the amount of squeezing out the excess sizing agent-containing liquid.

  Moreover, in this invention, after apply | coating the sizing agent which contains at least the above-mentioned aliphatic epoxy compound (A), the above-mentioned condensate (B), and the above-mentioned nonionic surfactant (C) to carbon fiber at least. It is preferable to perform heat treatment for 30 to 600 seconds in a temperature range of 160 to 260 ° C. The heat treatment conditions are preferably in a temperature range of 170 to 250 ° C. for 30 to 500 seconds, and more preferably in a temperature range of 180 to 240 ° C. for 30 to 300 seconds. When the heat treatment condition is less than 160 ° C. and / or less than 30 seconds, the interaction between the aliphatic epoxy compound (A) of the sizing agent and the oxygen-containing functional group on the carbon fiber surface is not promoted, and the carbon fiber Adhesiveness with the matrix resin may be insufficient, or the solvent may not be sufficiently removed by drying. On the other hand, when the heat treatment condition exceeds 260 ° C. and / or exceeds 600 seconds, decomposition and volatilization of the sizing agent occurs, the interaction with the carbon fiber is not promoted, and the adhesion between the carbon fiber and the matrix resin is increased. It may be insufficient.

  The heat treatment can also be performed by microwave irradiation and / or infrared irradiation. When the sizing agent-coated carbon fiber is heat-treated by microwave irradiation and / or infrared irradiation, the microwave penetrates into the carbon fiber and is absorbed, so that the carbon fiber which is the object to be heated can be heated to a desired temperature in a short time. Can be heated. In addition, since the inside of the carbon fiber can be quickly heated by microwave irradiation and / or infrared irradiation, the temperature difference between the inside and outside of the carbon fiber bundle can be reduced, and the adhesion unevenness of the sizing agent can be reduced. It becomes possible to do.

The sizing agent-coated carbon fiber according to the present invention produced as described above is obtained by X-ray photoelectron spectroscopy at a photoelectron escape angle of 15 ° using AlKα _1,2 using the sizing agent surface coated on the carbon fiber as an X-ray source. The height (cps) of the component of the binding energy (284.6 eV) attributed to (a) CHx, C—C, C═C in the C _1s core spectrum measured by (b) and (b) attributed to C—O The ratio (a) / (b) of the height (cps) of the component of the binding energy (286.1 eV) is 0.50 to 0.90. The sizing agent-coated carbon fiber according to the present invention has excellent adhesion to carbon fiber when (a) / (b) is in a specific range, that is, 0.50 to 0.90, and the sizing agent. Since the convergence and smoothness of the coated carbon fiber are increased, the processability is high, and the quality of the prepreg composed of the sizing agent coated carbon fiber and the carbon fiber reinforced composite material composed of the carbon fiber reinforced thermoplastic resin composition is improved. It was made by finding out.

Sizing agent applying carbon fiber according to the present invention, the C _1s inner shell spectrum measured by X-ray photoelectron spectroscopy sizing agent surface coated carbon fiber optoelectronic escape angle 15 ° (a) CHx, C -C, The ratio between the height (cps) of the component of the binding energy (284.6 eV) attributed to C = C and the height (cps) of the component of the binding energy (286.1 eV) attributed to (B) C—O (A) / (b) is preferably 0.55 or more, more preferably 0.57 or more. Moreover, ratio (a) / (b) becomes like this. Preferably it is 0.80 or less, More preferably, it is 0.74 or less. A large (a) / (b) indicates that there are many aromatic compounds on the surface and few aliphatic compounds.

  X-ray photoelectron spectroscopy measurement method is an analysis method that irradiates a sample carbon fiber with X-rays in an ultra-high vacuum and measures the kinetic energy of photoelectrons emitted from the surface of the carbon fiber with an apparatus called an energy analyzer. That's it. By examining the kinetic energy of the photoelectrons emitted from the carbon fiber surface of the sample, the binding energy converted from the energy value of the X-rays incident on the carbon fiber of the sample is uniquely determined. From the binding energy and the photoelectron intensity The type and concentration of elements present on the outermost surface (˜nm) of the sample and the chemical state thereof can be analyzed.

In the present invention, the peak ratio of (a) and (b) on the surface of the sizing agent-coated carbon fiber is determined by X-ray photoelectron spectroscopy according to the following procedure. Measurement was made at a photoelectron escape angle of 15 °. Cut the sizing agent-coated carbon fiber to 20 mm, spread and arrange it on a copper sample support, and then use AlKα _1,2 as the X-ray source and keep the sample chamber at 1 × 10 ⁻⁸ Torr for measurement. Is called. As correction of the peak accompanying charging during measurement, first, the binding energy value of the main peak of C _1s is adjusted to 286.1 eV. At this time, the peak area of C _1s is obtained by drawing a straight baseline in the range of 282 to 296 eV. Further, a linear base line of 282 to 296 eV obtained by calculating the area at the C _1s peak is defined as the origin (zero point) of the photoelectron intensity, and (b) the peak of the binding energy 286.1 eV attributed to the CO component is obtained. The height (cps: photoelectron intensity per unit time) and (a) the peak height (cps) of the binding energy 284.6 eV attributed to CHx, C—C, C = C are obtained, and (a) / ( b) is calculated.

The sizing agent-coated carbon fiber according to the present invention has a C1s inner shell spectrum (a) of the sizing agent surface coated on the carbon fiber, measured at a photoelectron escape angle of 55 ° by X-ray photoelectron spectroscopy using 400 eV X-rays. The height (cps) of the component of the bond energy (284.6 eV) attributed to CHx, C—C, C = C, and (b) of the component of the bond energy (286.1 eV) attributed to C—O It is preferable that the values of (I) and (II) obtained from the ratio (a) / (b) to the height (cps) satisfy the relationship of (III).
(I) The value of (a) / (b) on the surface of the sizing agent-coated carbon fiber before sonication (II) The sizing agent-coated carbon fiber is sonicated in an acetone solvent to reduce the sizing agent adhesion amount. The value of (a) / (b) (III) 0.50 ≦ (I) ≦ 0.90 and 0.6 <(II) on the surface of the sizing agent-coated carbon fiber washed to 0.09 to 0.20% by mass. ) / (I) <1.0.

  The fact that (I), which is the (a) / (b) value on the surface of the sizing agent-coated carbon fiber before ultrasonic treatment, falls within the above range means that there are many aromatic-derived compounds on the surface of the sizing agent. It shows that there are few compounds. The (a) / (b) value (I) before sonication is preferably 0.55 or more, more preferably 0.57 or more. Moreover, (I) which is (a) / (b) value before ultrasonic treatment is preferably 0.80 or less, more preferably 0.74 or less.

  The fact that (II) / (I), which is the ratio of (a) / (b) values on the sizing agent-coated carbon fiber surface before and after the ultrasonic treatment, falls within the above range, indicates that the inner layer of the sizing agent compared to the sizing agent surface. Indicates that the ratio of the aliphatic compound is large. (II) / (I) is preferably 0.65 or more. Further, (II) / (I) is preferably 0.85 or less.

  When the values of (I) and (II) satisfy the relationship of (III), the adhesion to carbon fiber is excellent and the convergence and smoothness of the sizing agent-coated carbon fiber are increased, so that the prepreg and carbon fiber reinforcement It is preferable because it is high in quality when used as a carbon fiber reinforced composite material made of a thermoplastic resin composition, and the processability is improved.

  The interfacial shear strength (IFSS) between the sizing agent-coated carbon fibers of the present invention and the epoxy resin is preferably 40 MPa or more. The interfacial shear strength between the single fiber and the epoxy resin in the present invention is a value defined as follows. When the interfacial shear strength is high, the adhesiveness tends to be high. The interfacial shear strength is more preferably 43 MPa or more. Here, the epoxy resin used for evaluation is bisphenol A type epoxy compound “jER (registered trademark)” 828 (manufactured by Mitsubishi Chemical Corporation) and metaphenylenediamine (manufactured by Sigma Aldrich Japan Co., Ltd.) 14.5. A resin comprising a mass part.

  Hereinafter, the evaluation details of the interfacial shear strength will be described. The evaluation is performed with reference to Drzal, L.T., Mater. Sci. Eng. A126, 289 (1990).

  That is, one single fiber having a length of 10 cm is taken out from the carbon fiber coated with the sizing agent. Both ends are fixed with an adhesive while a constant tension is applied to the single fiber in the longitudinal direction of the dumbbell mold. Then, in order to remove the water | moisture content adhering to carbon fiber and a mold, it vacuum-drys for 30 minutes or more at the temperature of 80 degreeC. The dumbbell mold is made of silicone rubber, and the shape of the casting part is a central part width of 5 mm, a length of 25 mm, a both end part width of 10 mm, and an overall length of 150 mm.

  In the mold after the above vacuum drying, in order to lower the viscosity of the bisphenol A type epoxy compound and dissolve the metaphenylenediamine, heat and mix at a temperature of 75 ° C. for 15 minutes, and vacuum defoaming at a temperature of 80 ° C. for about 15 minutes. After pouring the resin, using an oven, the temperature was raised to 75 ° C. at a temperature rising rate of 1.5 ° C./min, held for 2 hours, and then raised to a temperature of 125 ° C. at a temperature rising rate of 1.5 ° C./min. After holding for 2 hours, the temperature is lowered to a temperature of 30 ° C. at a temperature lowering rate of 2.5 ° C./min. Then, it demolds and a test piece is obtained.

A tensile force is applied to the test piece in the fiber axis direction (longitudinal direction), a tensile test is performed at a strain rate of 0.3% / second, and the number of fiber breaks in the range of 22 mm in the center of the test piece is measured with a polarizing microscope every 1% tension. , And the number of fiber breaks when the number of fiber breaks saturates and no single fiber breaks occurs is defined as N (pieces). Using the number of fiber breaks, the average break fiber length la (μm) = 22 × 1000 (μm) / N (pieces) is calculated. Further, the critical fiber length lc (μm) = (4/3) × la (μm) is calculated from the average breaking fiber length la. In the present invention, the interfacial shear strength (IFSS), which is an index of the adhesive strength between the carbon fiber and the resin interface, is calculated by the following equation. σ is the strand tensile strength, and d is the diameter of the carbon fiber single yarn.
Interfacial shear strength IFSS (MPa) = σ (MPa) × d (μm) / (2 × lc) (μm).

  In the present invention, the sizing agent applied to the carbon fiber has an epoxy value of 1.8 to 2.9 meq. / G is preferable. Epoxy value is 1.8 meq. / G or more improves the adhesion between the carbon fiber coated with the sizing agent and the matrix resin. Moreover, the epoxy value applied to the carbon fiber is 2.9 meq. / G or less is sufficient. The epoxy value of the applied sizing agent was 2.8 meq. / G or less is preferable, and 2.6 meq. / G or less is more preferable. Moreover, the epoxy value of the applied sizing agent was 1.9 meq. / G or more, 2.0 meq. / G or more is more preferable. The epoxy value of the sizing agent applied to the carbon fiber in the present invention was eluted from the fiber by immersing the sizing agent-coated carbon fiber in a solvent represented by N, N-dimethylformamide and performing ultrasonic cleaning. After that, the epoxy group can be opened with hydrochloric acid, and it can be determined by acid-base titration.

  In addition, the epoxy value of the sizing agent applied to the carbon fiber can be controlled by the epoxy value of the sizing agent used for application, the heat history in drying after application, and the like. In order to set the epoxy value of the applied sizing agent in the above range, the epoxy value of 2.1 to 5.6 meq. / G sizing agent is preferably applied.

  In this invention, it is preferable that the adhesion amount to the carbon fiber of a sizing agent is the range of 0.1-10.0 mass% with respect to sizing agent application | coating carbon fiber, More preferably, 0.2-3. It is in the range of 0% by mass. When the sizing agent adhesion amount is 0.1% by mass or more, when prepregizing and weaving the sizing agent-coated carbon fiber, it can withstand friction caused by a metal guide that passes therethrough, and generation of fluff can be suppressed. Excellent quality such as smoothness of prepreg and molded product. On the other hand, when the adhesion amount of the sizing agent is 10.0% by mass or less, the matrix resin is impregnated inside the carbon fiber without being hindered by the sizing agent film around the sizing agent-coated carbon fiber, and in the obtained composite material The generation of voids is suppressed, the quality of the composite material is excellent, and at the same time the mechanical properties are excellent.

  The amount of sizing agent attached was measured by measuring the change in mass before and after the heat treatment when about 2 ± 0.5 g of sizing agent-coated carbon fiber was sampled and heat-treated at 450 ° C. for 15 minutes in a nitrogen atmosphere. The mass change is divided by the mass before heat treatment (mass%).

  In the present invention, the thickness of the sizing agent layer applied to the carbon fiber and dried is preferably within a range of 2.0 to 20 nm, and the maximum value of the thickness does not exceed twice the minimum value. With such a uniform sizing agent layer, a large effect of improving adhesiveness can be obtained stably, and further, stable high-order workability can be obtained.

  In this invention, it is preferable that the adhesion amount to the carbon fiber of an aliphatic epoxy compound (A) is the range of 0.05-5.0 mass% with respect to sizing agent application | coating carbon fiber, More preferably, it is 0. .2 to 2.0% by mass. More preferably, it is 0.3-1.0 mass%. The adhesion amount of the aliphatic epoxy compound (A) is preferably 0.05% by mass or more, because the adhesion between the sizing agent-coated carbon fiber and the matrix resin is improved.

  In the present invention, when the sizing agent-coated carbon fiber is eluted with an acetonitrile / chloroform mixed solvent, the proportion of the aliphatic epoxy compound (A) eluted is 0.3 mass with respect to 100 parts by mass of the sizing agent-coated carbon fiber. Part or less. When the elution amount of the aliphatic epoxy compound (A) is 0.3 parts by mass or less, components other than the aliphatic epoxy compound (A) of the sizing agent-coated carbon fiber of the present invention increase, and smoothness, convergence, etc. In order to improve the quality, when the sizing agent-coated carbon fiber is used as a molding material with a prepreg or a thermoplastic resin composition, the quality is preferably improved. From this viewpoint, the proportion of the eluted aliphatic epoxy compound (A) is more preferably 0.1 parts by mass or less, and further preferably 0.05 parts by mass or less, with respect to 100 parts by mass of the sizing agent-coated carbon fiber. .

The proportion of the eluted aliphatic epoxy compound (A) was determined by immersing a sizing agent-coated carbon fiber test piece in an acetonitrile / chloroform mixture (volume ratio 9/1), performing ultrasonic cleaning for 20 minutes, and sizing agent. Can be analyzed under the following conditions using liquid chromatography.
・ Analytical column: Chromolis Performance RP-18e (4.6 × 100 mm)
-Mobile phase: Water / acetonitrile was used, and after 7 minutes from the start of analysis, water / acetonitrile = 60% / 40% to acetonitrile 100%, then 100% acetonitrile was retained for 12 minutes, and then 12.1 minutes By the time, water / acetonitrile = 60% / 40%, and water / acetonitrile = 60% / 40% was maintained until 17 minutes.
-Flow rate: 2.5 mL / min-Column temperature: 45 ° C
Detector: Evaporative light scattering detector (ELSD)
Detector temperature: 60 ° C.

  In this invention, it is preferable that the moisture content of sizing agent application | coating carbon fiber is 0.010-0.030 mass%. When the moisture content of the sizing agent-coated carbon fiber is 0.030% by mass or less, high mechanical properties of the carbon fiber-reinforced composite material can be maintained even under wet conditions. In particular, when a thermoplastic resin that is easily hydrolyzed is used, a decrease in molecular weight can be suppressed, which is preferable. The moisture content of the sizing agent-coated carbon fiber is preferably 0.024% by mass or less, and more preferably 0.022% by mass or less. Moreover, since the minimum of a moisture content is 0.010 mass% or more, since the uniform applicability | paintability of the sizing agent apply | coated to carbon fiber improves, it is preferable. 0.015 mass% or more is more preferable. The moisture content of the sizing agent-coated carbon fiber can be measured by weighing about 2 g of the sizing agent-coated carbon fiber and using a moisture meter such as KF-100 (capacity method Karl Fischer moisture meter) manufactured by Mitsubishi Chemical Analytech. The heating temperature during measurement is 150 ° C.

In the manufacturing method of sizing agent coated carbon fiber of the present invention, it is preferred that the polar component of the surface free energy is applied sizing agent to 8 mJ / m ² or more 50 mJ / m ² or less of carbon fiber. Since the polar component of the surface free energy is 8 mJ / m ² or more, the aliphatic epoxy compound (A) is closer to the carbon fiber surface, so that the adhesion is improved and the sizing layer is unevenly distributed. . When it is 50 mJ / m ² or less, the convergence between the carbon fibers is increased, so that the impregnation with the matrix resin is improved. Polar component of the surface free energy of the carbon fiber surface is more preferably 15 mJ / ^{m 2} or more 45 mJ / ^{m 2} or less, and most preferably 25 mJ / ^{m 2} or more 40 mJ / ^{m 2} or less.

  The sizing agent-coated carbon fiber of the present invention is suitably used in the form of, for example, tow, woven fabric, knitted fabric, braided string, web, mat, and chopped.

  The sizing agent-coated carbon fiber of the present invention can be used as a carbon fiber reinforced composite material in combination with a matrix resin. As the matrix resin, a thermosetting resin and a thermoplastic resin (the resin described here may be a resin composition) are used.

  Next, a carbon fiber reinforced thermosetting resin composite material using a thermosetting resin as the matrix resin will be described.

  In particular, for applications that require a high specific strength and specific elastic modulus, a tow in which carbon fibers are aligned in one direction is most suitable, and a method using a prepreg impregnated with a matrix resin is preferably used. .

  The sizing agent-coated carbon fiber of the present invention can be used for a prepreg and a carbon fiber reinforced composite material in combination with a thermosetting resin. In the present invention, the prepreg includes the sizing agent-coated carbon fibers described above or the sizing agent-coated carbon fibers produced by the method described above and a matrix resin.

  The thermosetting resin used in the present invention is not particularly limited as long as the crosslinking reaction proceeds by heat and at least partially forms a three-dimensional crosslinked structure. Examples of such thermosetting resins include epoxy resins, unsaturated polyester resins, vinyl ester resins, benzoxazine resins, phenol resins, urea resins, melamine resins, thermosetting polyimide resins, and the like. Two or more types of blended resins can also be used. In addition, these thermosetting resins may be self-curing by heating, or may be blended with a curing agent or a curing accelerator.

  The epoxy compound used for the epoxy resin is not particularly limited, and is a bisphenol type epoxy compound, an amine type epoxy compound, a phenol novolac type epoxy compound, a cresol novolac type epoxy compound, a resorcinol type epoxy compound, a phenol aralkyl type epoxy compound, One or more selected from naphthol aralkyl type epoxy compounds, dicyclopentadiene type epoxy compounds, epoxy compounds having a biphenyl skeleton, isocyanate-modified epoxy compounds, tetraphenylethane type epoxy compounds, triphenylmethane type epoxy compounds, etc. be able to.

  Here, the bisphenol type epoxy compound is obtained by glycidylation of two phenolic hydroxyl groups of a bisphenol compound. The bisphenol A type, the bisphenol F type, the bisphenol AD type, the bisphenol S type, or the halogen or alkyl of these bisphenols. Examples include substituted products and hydrogenated products. Moreover, not only a monomer but the high molecular weight body which has several repeating units can also be used conveniently.

  Commercially available bisphenol A type epoxy compounds include “jER (registered trademark)” 825, 828, 834, 1001, 1002, 1003, 1003F, 1004, 1004AF, 1005F, 1006FS, 1007, 1009, 1010 (and above, Mitsubishi Chemical) Etc.). Examples of the brominated bisphenol A type epoxy compound include “jER (registered trademark)” 505, 5050, 5051, 5054, 5057 (manufactured by Mitsubishi Chemical Corporation). Examples of commercially available hydrogenated bisphenol A type epoxy compounds include ST5080, ST4000D, ST4100D, and ST5100 (manufactured by Nippon Steel Chemical Co., Ltd.).

  Commercially available bisphenol F type epoxy compounds include “jER (registered trademark)” 806, 807, 4002P, 4004P, 4007P, 4009P, 4010P (above, manufactured by Mitsubishi Chemical Corporation), “Epiclon (registered trademark)” 830. 835 (above, manufactured by DIC Corporation), “Epototo (registered trademark)” YDF2001, YDF2004 (above, manufactured by Nippon Steel Chemical Co., Ltd.), and the like. Examples of the tetramethylbisphenol F type epoxy compound include YSLV-80XY (manufactured by Nippon Steel Chemical Co., Ltd.).

  Examples of the bisphenol S-type epoxy compound include “Epiclon (registered trademark)” EXA-154 (manufactured by DIC Corporation).

  Examples of the amine-type epoxy compound include tetraglycidyldiaminodiphenylmethane, triglycidylaminophenol, triglycidylaminocresol, tetraglycidylxylylenediamine, halogens thereof, alkynol-substituted products, and hydrogenated products.

  Commercially available products of tetraglycidyldiaminodiphenylmethane include “Sumiepoxy (registered trademark)” ELM434 (manufactured by Sumitomo Chemical Co., Ltd.), YH434L (manufactured by Nippon Steel Chemical Co., Ltd.), and “jER (registered trademark)” 604 (Mitsubishi Chemical). (Manufactured by Co., Ltd.), “Araldide (registered trademark)” MY720, MY721 (manufactured by Huntsman Advanced Materials Co., Ltd.), and the like. Commercially available products of triglycidylaminophenol or triglycidylaminocresol include “Sumiepoxy (registered trademark)” ELM100, ELM120 (manufactured by Sumitomo Chemical Co., Ltd.), “Araldide (registered trademark)” MY0500, MY0510, MY0600 (and above) , Huntsman Advanced Materials Co., Ltd.), “jER (registered trademark)” 630 (manufactured by Mitsubishi Chemical Corporation), and the like. Examples of commercially available tetraglycidylxylylenediamine and hydrogenated products thereof include TETRAD-X and TETRAD-C (manufactured by Mitsubishi Gas Chemical Co., Ltd.).

  Commercially available products of phenol novolac type epoxy compounds are “jER (registered trademark)” 152, 154 (manufactured by Mitsubishi Chemical Corporation), “Epicron (registered trademark)” N-740, N-770, N-775 ( As mentioned above, DIC Corporation) etc. are mentioned.

  As a commercial item of a cresol novolac type epoxy compound, “Epiclon (registered trademark)” N-660, N-665, N-670, N-673, N-695 (above, manufactured by DIC Corporation), EOCN-1020 , EOCN-102S, EOCN-104S (manufactured by Nippon Kayaku Co., Ltd.), and the like.

  Examples of commercially available resorcinol-type epoxy compounds include “Denacol (registered trademark)” EX-201 (manufactured by Nagase ChemteX Corporation).

  Examples of commercially available glycidyl aniline type epoxy compounds include GAN and GOT (manufactured by Nippon Kayaku Co., Ltd.).

  Examples of commercially available epoxy compounds having a biphenyl skeleton include “jER (registered trademark)” YX4000H, YX4000, YL6616 (manufactured by Mitsubishi Chemical Corporation), NC-3000 (manufactured by Nippon Kayaku Co., Ltd.), and the like. It is done.

  Commercially available dicyclopentadiene type epoxy compounds include “Epicron (registered trademark)” HP7200L (epoxy value 4.0 to 4.1 meq./g, softening point 54 to 58), “Epicron (registered trademark)” HP7200 ( Epoxy value 3.9 meq./g, softening point 59 to 63), “Epiclon (registered trademark)” HP7200H (epoxy value 3.6 meq./g, softening point 80 to 85), “Epiclon (registered trademark)” HP7200HH ( Epoxy 3.6 meq./g, softening point 87 to 92 (above, manufactured by Dainippon Ink & Chemicals, Inc.), XD-1000-L (epoxy value 3.9 to 4.2 meq./g, softening point 60) -70), XD-1000-2L (epoxy value 4.0-4.3 meq./g, softening point 53-63) (Nippon Kayaku Co., Ltd.), "Tactix ( Recorded trademark) "556 (epoxy value 4.3~4.7meq. / G, a softening point of 79 ° C.) (Vantico Inc Co., Ltd.) and the like.

  Examples of commercially available isocyanate-modified epoxy compounds include XAC4151, AER4152 (produced by Asahi Kasei Epoxy Co., Ltd.) and ACR1348 (produced by ADEKA Co., Ltd.) having an oxazolidone ring.

  Examples of commercially available tetraphenylethane type epoxy compounds include “jER (registered trademark)” 1031 (manufactured by Mitsubishi Chemical Corporation), which is a tetrakis (glycidyloxyphenyl) ethane type epoxy compound.

  As a commercial item of a triphenylmethane type epoxy compound, “Tactics (registered trademark)” 742 (manufactured by Huntsman Advanced Materials Co., Ltd.) and the like can be mentioned.

  As unsaturated polyester resin, what melt | dissolved the unsaturated polyester obtained by making the acid component and alcohol which contain (alpha), (beta) -unsaturated dicarboxylic acid react in a polymerizable unsaturated monomer is mentioned. Examples of the α, β-unsaturated dicarboxylic acid include maleic acid, fumaric acid, itaconic acid and the like, derivatives of these acid anhydrides and the like, and these may be used in combination of two or more. In addition, as necessary, as an acid component other than α, β-unsaturated dicarboxylic acid, saturated dicarboxylic acid such as phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, adipic acid, sebacic acid, and acid anhydrides thereof, etc. The derivative may be used in combination with an α, β-unsaturated dicarboxylic acid.

  Examples of the alcohol include aliphatic glycols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,4-butanediol, cyclohexane Alicyclic diols such as pentanediol and cyclohexanediol, hydrogenated bisphenol A, bisphenol A propylene oxide (1 to 100 mol) adducts, aromatic diols such as xylene glycol, polyhydric alcohols such as trimethylolpropane and pentaerythritol, etc. These may be used in combination of two or more thereof.

  Specific examples of the unsaturated polyester resin include, for example, a condensate of fumaric acid or maleic acid and bisphenol A ethylene oxide (hereinafter abbreviated as EO) adduct, fumaric acid or maleic acid and bisphenol A propylene oxide (hereinafter referred to as “unsaturated polyester resin”). Abbreviated as PO.) Condensates with adducts and fumaric acid or maleic acid with EO and PO adducts of bisphenol A (addition of EO and PO may be random or block), etc. These condensates may be dissolved in a monomer such as styrene as necessary. Commercially available unsaturated polyester resins include “Yupika (registered trademark)” (manufactured by Nippon Yupica), “Rigolac (registered trademark)” (manufactured by Showa Denko), “Polyset (registered trademark)” (Manufactured by Hitachi Chemical Co., Ltd.).

  Examples of the vinyl ester resin include epoxy (meth) acrylate obtained by esterifying the epoxy compound and an α, β-unsaturated monocarboxylic acid. Examples of the α, β-unsaturated monocarboxylic acid include acrylic acid, methacrylic acid, crotonic acid, tiglic acid and cinnamic acid, and two or more of these may be used in combination. Specific examples of the vinyl ester resin include, for example, a modified bisphenol type epoxy compound (meth) acrylate (terminal (meth) obtained by reacting an epoxy group of a bisphenol A type epoxy compound and a carboxyl group of (meth) acrylic acid). Acrylate-modified resins and the like), and these modified products may be dissolved in a monomer such as styrene as necessary. Commercially available vinyl ester resins include “Dicklight (registered trademark)” (manufactured by DIC Corporation), “Neopol (registered trademark)” (manufactured by Nippon Yupica Corporation), “Lipoxy (registered trademark)” (Showa) Polymer Co., Ltd.).

  Examples of the benzoxazine resin include o-cresol aniline type benzoxazine resin, m-cresol aniline type benzoxazine resin, p-cresol aniline type benzoxazine resin, phenol-aniline type benzoxazine resin, phenol-methylamine type benzoxazine resin, Phenol-cyclohexylamine type benzoxazine resin, phenol-m-toluidine type benzoxazine resin, phenol-3,5-dimethylaniline type benzoxazine resin, bisphenol A-aniline type benzoxazine resin, bisphenol A-amine type benzoxazine resin, Bisphenol F-aniline type benzoxazine resin, bisphenol S-aniline type benzoxazine resin, dihydroxydiphenylsulfone-aniline type Nzooxazine resin, dihydroxydiphenyl ether-aniline type benzoxazine resin, benzophenone type benzoxazine resin, biphenyl type benzoxazine resin, bisphenol AF-aniline type benzoxazine resin, bisphenol A-methylaniline type benzoxazine resin, phenol-diaminodiphenylmethane type benzoxazine Examples thereof include resins, triphenylmethane type benzoxazine resins, and phenolphthalein type benzoxazine resins. Examples of commercially available benzoxazine resins include BF-BXZ, BS-BXZ, BA-BXZ (manufactured by Konishi Chemical Industry Co., Ltd.).

  Examples of the phenolic resin include resins obtained by condensation of phenols such as phenol, cresol, xylenol, t-butylphenol, nonylphenol, cashew oil, lignin, resorcin, and catechol with aldehydes such as formaldehyde, acetaldehyde, and furfural. , Novolak resins and resol resins. The novolak resin can be obtained by reacting phenol and formaldehyde in the same amount or in excess of phenol in the presence of an acid catalyst such as oxalic acid. The resole resin can be obtained by reacting phenol and formaldehyde in the same amount or in excess of formaldehyde in the presence of a base catalyst such as sodium hydroxide, ammonia or organic amine. Commercially available phenolic resins include “Sumilite Resin (registered trademark)” (manufactured by Sumitomo Bakelite Co., Ltd.), Resitop (manufactured by Gunei Chemical Industry Co., Ltd.), “AV Light (registered trademark)” (Asahi Organic Materials) Kogyo Co., Ltd.).

  Examples of the urea resin include a resin obtained by condensation of urea and formaldehyde. Examples of commercially available urea resins include UA-144 (manufactured by Sunbake Co., Ltd.).

  Examples of the melamine resin include a resin obtained by polycondensation of melamine and formaldehyde. Examples of commercially available melamine resins include “Nicalac (registered trademark)” (manufactured by Sanwa Chemical Co., Ltd.).

  Examples of the thermosetting polyimide resin include a resin containing at least one imide ring in the main structure and one or more selected from phenylethynyl group, nadiimide group, maleimide group, acetylene group and the like in the terminal or main chain. It is done. Examples of commercially available polyimide resin include PETI-330 (manufactured by Ube Industries).

  Among these thermosetting resins, it is preferable to use an epoxy resin containing at least an epoxy compound (E) because it has an advantage of excellent balance of mechanical properties and small curing shrinkage. In particular, an epoxy resin containing at least a glycidylamine type epoxy compound having a plurality of functional groups as the epoxy compound (E) is preferable. An epoxy resin containing at least a glycidylamine type epoxy compound having a plurality of functional groups is preferable because it has a high multi-crosslinking density and can improve the heat resistance and compressive strength of the carbon fiber reinforced composite material.

  Examples of the glycidylamine-type epoxy compound having a plurality of functional groups include tetraglycidyldiaminodiphenylmethane, triglycidylaminophenol and triglycidylaminocresol, N, N-diglycidylaniline, N, N-diglycidyl-o-toluidine, N , N-diglycidyl-4-phenoxyaniline, N, N-diglycidyl-4- (4-methylphenoxy) aniline, N, N-diglycidyl-4- (4-tert-butylphenoxy) aniline and N, N-diglycidyl- 4- (4-phenoxyphenoxy) aniline and the like can be mentioned. In many cases, these compounds are obtained by adding epichlorohydrin to a phenoxyaniline derivative and cyclizing with an alkali compound. Since the viscosity increases as the molecular weight increases, N, N-diglycidyl-4-phenoxyaniline is particularly preferably used from the viewpoint of handleability.

  Specific examples of the phenoxyaniline derivative include 4-phenoxyaniline, 4- (4-methylphenoxy) aniline, 4- (3-methylphenoxy) aniline, 4- (2-methylphenoxy) aniline, 4- (4 -Ethylphenoxy) aniline, 4- (3-ethylphenoxy) aniline, 4- (2-ethylphenoxy) aniline, 4- (4-propylphenoxy) aniline, 4- (4-tert-butylphenoxy) aniline, 4- (4-cyclohexylphenoxy) aniline, 4- (3-cyclohexylphenoxy) aniline, 4- (2-cyclohexylphenoxy) aniline, 4- (4-methoxyphenoxy) aniline, 4- (3-methoxyphenoxy) aniline, 4- (2-methoxyphenoxy) aniline, 4- (3-phenoxyf) Noxy) aniline, 4- (4-phenoxyphenoxy) aniline, 4- [4- (trifluoromethyl) phenoxy] aniline, 4- [3- (trifluoromethyl) phenoxy] aniline, 4- [2- (trifluoro) Methyl) phenoxy] aniline, 4- (2-naphthyloxyphenoxy) aniline, 4- (1-naphthyloxyphenoxy) aniline, 4-[(1,1′-biphenyl-4-yl) oxy] aniline, 4- ( 4-nitrophenoxy) aniline, 4- (3-nitrophenoxy) aniline, 4- (2-nitrophenoxy) aniline, 3-nitro-4-aminophenyl phenyl ether, 2-nitro-4- (4-nitrophenoxy) Aniline, 4- (2,4-dinitrophenoxy) aniline, 3-nitro-4-phenoxyaniline, -(2-chlorophenoxy) aniline, 4- (3-chlorophenoxy) aniline, 4- (4-chlorophenoxy) aniline, 4- (2,4-dichlorophenoxy) aniline, 3-chloro-4- (4- Chlorophenoxy) aniline, 4- (4-chloro-3-tolyloxy) aniline, and the like.

  Commercially available products of tetraglycidyldiaminodiphenylmethane include, for example, “Sumiepoxy (registered trademark)” ELM434 (manufactured by Sumitomo Chemical Co., Ltd.), YH434L (manufactured by Tohto Kasei Co., Ltd.), “Araldite (registered trademark)” MY720 (Huntsman Advanced) -Materials Co., Ltd.), "jER (registered trademark)" 604 (Mitsubishi Chemical Co., Ltd.), etc. can be used. Examples of triglycidylaminophenol and triglycidylaminocresol include, for example, “Sumiepoxy (registered trademark)” ELM100 (manufactured by Sumitomo Chemical Co., Ltd.), “Araldite (registered trademark)” MY0510, “Araldite (registered trademark)” MY0600 (and above) , Huntsman Advanced Materials Co., Ltd.), “jER (registered trademark)” 630 (Mitsubishi Chemical Co., Ltd.), and the like can be used.

  Among the above-mentioned glycidylamine type epoxy compounds having a plurality of functional groups, an aromatic epoxy compound having at least one glycidylamine skeleton and having 3 or more epoxy groups is preferable.

  An epoxy resin containing a glycidylamine type aromatic epoxy compound having 3 or more epoxy groups has an effect of improving heat resistance, and the proportion thereof is preferably 30 to 100% by mass in the epoxy resin, more preferably. A ratio is 50 mass% or more. The ratio of the glycidylamine type aromatic epoxy compound is preferably 30% by mass or more, since the compressive strength of the carbon fiber reinforced composite material is improved and the heat resistance is improved.

  When using these epoxy compounds, you may add catalysts and hardening | curing agents, such as an acid and a base, as needed. For example, for curing epoxy resins, Lewis acids such as boron halide complexes and p-toluenesulfonate, and polyamine curing agents such as diaminodiphenylsulfone, diaminodiphenylmethane and their derivatives and isomers are preferably used.

  In the prepreg of the present invention, the latent curing agent (F) is preferably used as the curing agent. The latent curing agent (F) described here is a curing agent for the thermosetting resin of the present invention, and is a curing agent that is activated by applying a temperature and reacts with a reactive group such as an epoxy group, The reaction is preferably activated at 70 ° C. or higher. Here, activation at 70 ° C. means that the reaction start temperature is in the range of 70 ° C. Such reaction start temperature (hereinafter referred to as activation temperature) can be determined by, for example, differential scanning calorimetry (DSC). Specifically, the epoxy value is 5.2 to 5.4 meq. Tangent of the inflection point of the exothermic curve obtained by differential scanning calorimetry and the tangent of the baseline for an epoxy resin composition obtained by adding 10 parts by mass of the curing agent to be evaluated to 100 parts by mass of the bisphenol A type epoxy compound of about 10 g / g It is calculated from the intersection of

  The latent curing agent (F) is preferably an aromatic amine curing agent, or dicyandiamide or a derivative thereof. The aromatic amine curing agent is not particularly limited as long as it is an aromatic amine used as an epoxy resin curing agent. Specifically, 3,3′-diaminodiphenylsulfone (3,3′- DDS), 4,4′-diaminodiphenylsulfone (4,4′-DDS), diaminodiphenylmethane (DDM), 3,3′-diisopropyl-4,4′-diaminodiphenylmethane, 3,3′-di-t- Butyl-4,4′-diaminodiphenylmethane, 3,3′-diethyl-5,5′-dimethyl-4,4′-diaminodiphenylmethane, 3,3′-diisopropyl-5,5′-dimethyl-4,4 ′ -Diaminodiphenylmethane, 3,3'-di-t-butyl-5,5'-dimethyl-4,4'-diaminodiphenylmethane, 3,3 ', 5,5'-tetra Ethyl-4,4′-diaminodiphenylmethane, 3,3′-diisopropyl-5,5′-diethyl-4,4′-diaminodiphenylmethane, 3,3′-di-t-butyl-5,5′-diethyl- 4,4′-diaminodiphenylmethane, 3,3 ′, 5,5′-tetraisopropyl-4,4′-diaminodiphenylmethane, 3,3′-di-t-butyl-5,5′-diisopropyl-4,4 '-Diaminodiphenylmethane, 3,3', 5,5'-tetra-t-butyl-4,4'-diaminodiphenylmethane, diaminodiphenyl ether (DADPE), bisaniline, benzyldimethylaniline, 2- (dimethylaminomethyl) phenol ( DMP-10), 2,4,6-tris (dimethylaminomethyl) phenol (DMP-30), 2,4,6 Can be used tris (dimethylaminomethyl) 2-ethylhexanoic acid ester of phenol. These may be used alone or in admixture of two or more.

  Commercially available aromatic amine curing agents (E1) include Seika Cure S (manufactured by Wakayama Seika Kogyo Co., Ltd.), MDA-220 (manufactured by Mitsui Chemicals, Inc.), “jER Cure (registered trademark)” W (Japan) Epoxy Resin Co., Ltd.), 3,3′-DAS (Mitsui Chemicals Co., Ltd.), “Lonzacure (registered trademark)” M-DEA (Lonza Co., Ltd.), “Lonzacure (registered trademark)” M -DIPA (manufactured by Lonza), "Lonzacure (registered trademark)" M-MIPA (manufactured by Lonza), "Lonzacure (registered trademark)" DETDA 80 (manufactured by Lonza), and the like.

  A dicyandiamide derivative or a derivative thereof is a compound reacted with at least one of an amino group, an imino group and a cyano group. For example, o-tolylbiguanide, diphenylbiguanide, dicyandiamide amino group, imino group or cyano group. In this group, the epoxy group of the epoxy compound used in the epoxy resin composition is pre-reacted.

  As a commercial item of dicyandiamide or its derivative, DICY-7, DICY-15 (above, Japan Epoxy Resin Co., Ltd. product) etc. are mentioned.

  Curing agents other than aromatic amine curing agents, dicyandiamide or derivatives thereof include amines such as alicyclic amines, phenolic compounds, acid anhydrides, polyaminoamides, organic acid hydrazides, and isocyanates in combination with aromatic diamine curing agents. It may be used.

  As the phenol compound used as the latent curing agent, the phenol compounds exemplified above as the matrix resin can be arbitrarily used.

  Moreover, as a combination of the sizing agent according to the present invention and dicyandiamide, the following combinations are preferable.

  Moreover, it is preferable that the total amount of a latent hardening | curing agent contains the quantity from which an active hydrogen group becomes the range of 0.6-1.2 equivalent with respect to 1 equivalent of epoxy groups of all the epoxy resin components, More preferably, it is 0.00. The amount is in the range of 7 to 0.9 equivalent. Here, the active hydrogen group means a functional group that can react with the epoxy group of the curing agent component, and when the active hydrogen group is less than 0.6 equivalent, the reaction rate, heat resistance, and elastic modulus of the cured product. In some cases, the glass transition temperature and strength of the fiber reinforced composite material may be insufficient. If the active hydrogen group exceeds 1.2 equivalents, the reaction rate, glass transition temperature, and elastic modulus of the cured product are sufficient, but the plastic deformation ability is insufficient, so the impact resistance of the carbon fiber reinforced composite material May be insufficient.

  Moreover, when a thermosetting resin is an epoxy resin, a hardening accelerator can also be mix | blended in order to accelerate hardening.

  Examples of the curing accelerator include urea compounds, tertiary amines and salts thereof, imidazoles and salts thereof, triphenylphosphine or derivatives thereof, carboxylic acid metal salts, Lewis acids, Bronsted acids and salts thereof, and the like. Among these, a urea compound is preferably used from the balance between storage stability and catalytic ability.

  In particular, when a urea compound is used as the curing accelerator, it is preferable that the latent curing agent is used in combination with dicyandiamide or a derivative thereof.

  Examples of the urea compound include N, N-dimethyl-N ′-(3,4-dichlorophenyl) urea, toluenebis (dimethylurea), 4,4′-methylenebis (phenyldimethylurea), 3-phenyl-1, 1-dimethylurea or the like can be used. Examples of commercially available urea compounds include DCMU99 (manufactured by Hodogaya Chemical Co., Ltd.), “Omicure (registered trademark)” 24, 52, 94 (manufactured by Emerald Performance Materials, LLC).

  It is preferable that the compounding quantity of a urea compound shall be 1-4 mass parts with respect to 100 mass parts of all the epoxy resin components. When the compounding quantity of this urea compound is less than 1 mass part, reaction may not fully advance and the elasticity modulus and heat resistance of hardened | cured material may be insufficient. Moreover, when the compounding quantity of this urea compound exceeds 4 mass parts, since the self-polymerization reaction of an epoxy compound inhibits reaction with an epoxy compound and a hardening | curing agent, the toughness of hardened | cured material is insufficient, and an elasticity modulus May decrease.

  Moreover, the thing which made these epoxy resin and hardening | curing agent, or some of them pre-react can be mix | blended in a composition. This method may be effective for viscosity adjustment and storage stability improvement.

  The prepreg of the present invention preferably contains a thermoplastic resin in order to adjust toughness and fluidity. From the viewpoint of heat resistance, polysulfone, polyethersulfone, polyetherimide, polyimide, polyamide, polyamide More preferably, it contains at least one selected from imide, polyphenylene ether, phenoxy resin, and polyolefin. Moreover, the oligomer of a thermoplastic resin can be included. Moreover, an elastomer, a filler, and another additive can also be mix | blended. Note that the thermoplastic resin is preferably contained in the thermosetting resin constituting the prepreg. Furthermore, when an epoxy resin is used as the thermosetting resin, as the thermoplastic resin, a thermoplastic resin soluble in the epoxy resin, organic particles such as rubber particles and thermoplastic resin particles, and the like can be blended. As the thermoplastic resin soluble in the epoxy resin, a thermoplastic resin having a hydrogen bonding functional group that can be expected to improve the adhesion between the resin and the carbon fiber is preferably used.

  As the thermoplastic resin soluble in epoxy resin and having a hydrogen bonding functional group, a thermoplastic resin having an alcoholic hydroxyl group, a thermoplastic resin having an amide bond, or a thermoplastic resin having a sulfonyl group can be used.

  Examples of the thermoplastic resin having an alcoholic hydroxyl group include polyvinyl acetal resins such as polyvinyl formal and polyvinyl butyral, polyvinyl alcohol, and phenoxy resins. Examples of the thermoplastic resin having an amide bond include polyamide, polyimide, Polyvinyl pyrrolidone can be mentioned, and as a thermoplastic resin having a sulfonyl group, polysulfone can be mentioned. Polyamide, polyimide and polysulfone may have a functional group such as an ether bond and a carbonyl group in the main chain. The polyamide may have a substituent on the nitrogen atom of the amide group.

  Examples of commercially available thermoplastic resins that are soluble in epoxy resins and have hydrogen-bonding functional groups include, as polyvinyl acetal resins, Denkabutyral (manufactured by Denki Kagaku Kogyo Co., Ltd.), “Vinylec (registered trademark)” (Chisso ( Manufactured by Co., Ltd.), “UCAR (registered trademark)” PKHP (made by Union Carbide Co., Ltd.) as a phenoxy resin, “Macromelt (registered trademark)” (produced by Henkel Hakusui Co., Ltd.), “Amilan (registered) Trademark) ”(manufactured by Toray Industries, Inc.),“ Ultem (registered trademark) ”(manufactured by SABIC Innovative Plastics Japan LLC),“ Matrimid (registered trademark) ”5218 (manufactured by Ciba), and“ polysulfone ” "Sumika Excel (registered trademark)" (manufactured by Sumitomo Chemical Co., Ltd.), "UDEL (registered trademark)", "RADE" (Registered trademark) "(or, Solvay Advanced Polymers Co., Ltd.), as a polyvinylpyrrolidone," Luviskol (registered trademark) "can be exemplified (BASF Japan Ltd.).

  In addition, the acrylic resin has high compatibility with the epoxy resin, and is suitably used for fluidity adjustment such as thickening. Examples of commercially available acrylic resins include “Dianal (registered trademark)” BR series (manufactured by Mitsubishi Rayon Co., Ltd.), “Matsumoto Microsphere (registered trademark)” M, M100, M500 (Matsumoto Yushi Seiyaku Co., Ltd.) And “Nanostrength (registered trademark)” E40F, M22N, M52N (manufactured by Arkema Co., Ltd.), and the like.

  In particular, polyethersulfone and polyetherimide are preferable because these effects can be exhibited without substantially impairing heat resistance. As the polyether sulfone, “Sumika Excel (registered trademark)” 3600P, “Sumika Excel” (registered trademark) 5003P, “Sumika Excel (registered trademark)” 5200P, “Sumika Excel (registered trademark)”, Sumitomo Chemical Co., Ltd. 7200P, “Virantage (registered trademark)” PESU VW-10200, “Virantage (registered trademark)” “PESU VW-10700 (registered trademark)”, and the above (manufactured by Solvay Advance Polymers), “ Ultrason (registered trademark) "2020SR (manufactured by BASF Corp.), polyetherimide includes" Ultem (registered trademark) "1000," Ultem (registered trademark) "1010," Ultem (registered trademark) "1040 (above, SABIC Innovative Plastics Japan Joint Company, Ltd.) and the like can be used.

  The thermoplastic resin is preferably uniformly dissolved in the epoxy resin composition or finely dispersed in the form of particles so as not to hinder the prepreg manufacturing process centering on impregnation.

  In addition, the amount of the thermoplastic resin to be dissolved in the epoxy resin composition is preferably 1 to 40 parts by mass, more preferably 1 to 25 parts by mass with respect to 100 parts by mass of the epoxy resin. On the other hand, when used in a dispersed state, the amount is preferably 10 to 40 parts by mass, more preferably 15 to 30 parts by mass with respect to 100 parts by mass of the epoxy resin. If the thermoplastic resin is less than this blending amount, the effect of improving toughness may be insufficient. Moreover, when a thermoplastic resin exceeds the said range, impregnation property, tack drape, and heat resistance may fall.

  Furthermore, in order to modify the matrix resin of the present invention, in addition to the thermoplastic resin described above, a thermosetting resin other than an epoxy resin, an elastomer, a filler, rubber particles, thermoplastic resin particles, inorganic particles, and other additives are added. It can also be blended.

  Rubber particles can also be blended with the epoxy resin preferably used in the present invention. As such rubber particles, cross-linked rubber particles, and core-shell rubber particles obtained by graft polymerization of a different polymer on the surface of the cross-linked rubber particles are preferably used from the viewpoint of handleability and the like.

  As commercial products of crosslinked rubber particles, FX501P (manufactured by JSR Co., Ltd.) composed of a crosslinked product of carboxyl-modified butadiene-acrylonitrile copolymer, CX-MN series (manufactured by Nippon Shokubai Co., Ltd.) composed of acrylic rubber fine particles, YR-500 series (manufactured by Nippon Steel Chemical Co., Ltd.) and the like can be used.

  Commercially available core-shell rubber particles include, for example, “Paraloid (registered trademark)” EXL-2655 (manufactured by Kureha Chemical Co., Ltd.), acrylic ester / methacrylic ester, composed of a butadiene / alkyl methacrylate / styrene copolymer. "STAPHYLOID (registered trademark)" AC-3355 made of a copolymer, TR-2122 (above, manufactured by Takeda Pharmaceutical Co., Ltd.), "PARARAID (registered trademark)" made of a copolymer of butyl acrylate and methyl methacrylate “EXL-2611, EXL-3387 (manufactured by Rohm & Haas)”, “Kane Ace (registered trademark)” MX (manufactured by Kaneka Corporation), and the like can be used.

  As the thermoplastic resin particles, those similar to the various thermoplastic resins exemplified above can be used. Of these, polyamide particles and polyimide particles are preferably used. Among polyamides, nylon 12, nylon 6, nylon 11, nylon 6/12 copolymer, and nylon modified with an epoxy compound (epoxy modified nylon) are particularly good. Since the adhesive strength with the thermosetting resin can be given, the delamination strength of the carbon fiber reinforced composite material at the time of falling weight impact is high, and the impact resistance improvement effect is high, which is preferable. As commercial products of polyamide particles, SP-500, SP-10 (manufactured by Toray Industries, Inc.), “Orgasol (registered trademark)” (manufactured by Arkema Co., Ltd.) and the like can be used.

  The shape of the thermoplastic resin particles may be spherical particles, non-spherical particles, or porous particles, but the spherical shape is superior in viscoelasticity because it does not deteriorate the flow characteristics of the resin, and there is no origin of stress concentration. This is a preferred embodiment in terms of giving high impact resistance. In the present invention, inorganic particles such as silica, alumina, smectite, and synthetic mica are blended in the epoxy resin composition in order to adjust fluidity such as thickening of the epoxy resin composition within a range that does not impair the effects of the present invention. be able to.

  The prepreg of the present invention is also preferably used by mixing conductive fillers for the purpose of increasing the contact probability between carbon fibers and improving the conductivity of the carbon fiber reinforced composite material. Examples of such conductive fillers include carbon black, carbon nanotube, vapor grown carbon fiber (VGCF), fullerene, metal nanoparticles, carbon particles, metal-plated thermoplastic resin particles, and metal-plated metals. The thermosetting resin particle | grains etc. which were illustrated previously are mentioned, It may be used independently or may be used together. Of these, carbon black and carbon particles that are inexpensive and highly effective are preferably used. For example, furnace black, acetylene black, thermal black, channel black, ketjen black, and the like can be used. Carbon black blended in two or more types is also preferably used. Further, as such carbon particles, “Bell Pearl (registered trademark)” C-600, C-800, C-2000 (manufactured by Kanebo Co., Ltd.), “NICABEADS (registered trademark)” ICB, PC, MC (Nippon Carbon Co., Ltd.) And the like). Specific examples of the metal-plated thermosetting resin particles include “Micropearl (registered trademark)” AU215, in which divinylbenzene polymer particles are plated with nickel and then gold is plated thereon.

  Next, the manufacturing method of the prepreg of this invention is demonstrated.

  The prepreg of the present invention is obtained by impregnating a sizing agent-coated carbon fiber bundle with a thermosetting resin composition that is a matrix resin. The prepreg can be produced by, for example, a wet method in which a matrix resin is dissolved in a solvent such as methyl ethyl ketone or methanol to lower the viscosity and impregnated, or a hot melt method in which the viscosity is lowered by heating and impregnated.

  In the wet method, after sizing agent-coated carbon fiber bundles are immersed in a liquid containing a matrix resin, the prepreg can be obtained by pulling up and evaporating the solvent using an oven or the like.

  In addition, in the hot melt method, a method of directly impregnating a carbon resin bundle coated with a sizing agent with a matrix resin whose viscosity has been reduced by heating, or a film in which a matrix resin composition is once coated on release paper or the like is first prepared. A prepreg can be produced by a method in which the film is laminated from both sides or one side of the sizing agent-coated carbon fiber bundle and heated and pressed to impregnate the sizing agent-coated carbon fiber bundle into the sizing agent-coated carbon fiber bundle. The hot melt method is a preferable means because there is no solvent remaining in the prepreg.

  In order to form a carbon fiber reinforced composite material using the prepreg of the present invention, a method of heat-curing a matrix resin while applying pressure to the laminate after laminating the prepreg can be used.

  Examples of methods for applying heat and pressure include a press molding method, an autoclave molding method, a bagging molding method, a wrapping tape method, and an internal pressure molding method. Especially for sporting goods, the wrapping tape method and the internal pressure molding method are preferably employed. The For aircraft applications where higher quality and higher performance laminated composite materials are required, the autoclave molding method is preferably employed. A press molding method is preferably used for various vehicle exteriors.

  The carbon fiber mass fraction of the prepreg of the present invention is preferably 40 to 90 mass%, more preferably 50 to 80 mass%. If the carbon fiber mass fraction is too low, the mass of the resulting composite material may be excessive, which may impair the advantages of the fiber-reinforced composite material having excellent specific strength and specific elastic modulus, and the carbon fiber mass fraction may be high. If the amount is too high, poor impregnation of the matrix resin composition occurs, and the resulting composite material tends to have a lot of voids, and the mechanical properties thereof may be greatly deteriorated.

  The sizing agent-coated carbon fiber in the present invention has high convergence, smoothness, and high adhesiveness, so that it can be arbitrarily selected according to the intended use such as open mold, pressure molding, continuous molding, and matched die molding. A carbon fiber reinforced composite material can be obtained by a molding method.

  In addition, as a method for obtaining a carbon fiber reinforced composite material in the present invention, in addition to autoclave molding using the above prepreg, hand lay-up, RTM, “SCRIMP (registered trademark)”, filament winding, pultrusion and SMC press molding. A molding method such as reaction injection molding or resin film infusion can be selected and applied according to the purpose. By applying any of these molding methods, a fiber-reinforced composite material containing the above-described sizing agent-coated carbon fiber and a cured product of the thermosetting resin composition can be obtained.

  Next, a carbon fiber reinforced thermoplastic resin composition using a thermoplastic resin as a matrix resin and a carbon fiber reinforced composite material formed by molding the same will be described.

  The sizing agent-coated carbon fiber of the present invention is preferably used as a carbon fiber reinforced thermoplastic resin composition. The carbon fiber reinforced thermoplastic resin and carbon fiber reinforced composite material according to the present invention will be described.

  The sizing agent-coated carbon fiber of the present invention is preferable because it has high bundling property and smoothness, and when used as a carbon fiber reinforced thermoplastic resin, the resulting molded article has good quality and composite properties are improved.

  Examples of the thermoplastic resin used in the present invention include polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), and liquid crystal polyester; polyethylene (PE), polypropylene (PP), polybutylene, acid-modified polyethylene (m-PE), acid-modified polypropylene (m-PP), polyolefin resins such as acid-modified polybutylene; polyoxymethylene (POM), polyamide (PA), Polyarylene sulfide resins such as polyphenylene sulfide (PPS); polyketone (PK), polyether ketone (PEK), polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polyether Fluoronitrile resin such as polytetrafluoroethylene; crystalline resin such as liquid crystal polymer (LCP); polystyrene resin such as polystyrene (PS), acrylonitrile styrene (AS), acrylonitrile butadiene styrene (ABS), polycarbonate (PC), polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), unmodified or modified polyphenylene ether (PPE), polyimide (PI), polyamideimide (PAI), polyetherimide (PEI), polysulfone ( PSU), polyethersulfone, polyarylate (PAR), and other amorphous resins; phenolic resins, phenoxy resins, polystyrene elastomers, polyolefin elastomers, polyurethane elastomers, At least one thermoplastic selected from various copolymers such as reester elastomers, polyamide elastomers, polybutadiene elastomers, polyisoprene elastomers, fluororesins and acrylonitrile elastomers, and their copolymers and modified products. Resins are preferably used.

  Among them, at least one thermoplastic resin selected from the group consisting of polyarylene sulfide resins, polyether ether ketone resins, polyphenylene ether resins, polyoxymethylene resins, polyester resins, polycarbonate resins, polystyrene resins and polyolefin resins. If so, it is preferable because the interaction with the condensate (B) is large and the interaction between the sizing agent and the thermoplastic resin is strengthened to form a strong interface and the physical properties of the resulting composite are improved.

  In addition, the thermoplastic resin used in the present invention is preferably a polyarylene sulfide resin or a polyether ether ketone resin from the viewpoint of heat resistance. From the viewpoint of dimensional stability, polyphenylene ether resin is preferable. From the viewpoint of friction and wear characteristics, polyoxymethylene resin is preferred. From the viewpoint of strength, a polyamide resin is preferable. From the viewpoint of surface appearance, an amorphous resin such as polycarbonate or polystyrene resin is preferable. From the viewpoint of lightness, polyolefin resin is preferable.

  More preferably, it is at least one selected from polyarylene sulfide resin, polycarbonate resin, polystyrene resin, and polyolefin resin, or polyamide. Polyarylene sulfide resins are particularly preferred from the viewpoint of heat resistance, polystyrene resins such as ABS from the viewpoint of dimensional stability, and polyolefin resins from the viewpoint of light weight.

  In addition, when a highly water-absorbing resin typified by polyamide or the like is used, it is preferable because the physical properties are maintained even during water absorption due to the effect of lowering the moisture content due to the condensate (B) on the carbon fiber surface. In particular, a polyamide resin is preferable because of its high strength.

  In addition, as a thermoplastic resin, the thermoplastic resin composition containing multiple types of these thermoplastic resins may be used in the range which does not impair the objective of this invention.

  Next, the preferable aspect for manufacturing the carbon fiber reinforced thermoplastic resin composition of this invention is demonstrated.

  In the method for producing a carbon fiber reinforced thermoplastic resin composition in the present invention, the aliphatic epoxy compound (A) and the condensate (B), the nonionic surfactant (C) with respect to the total amount of the sizing agent excluding the solvent. It is preferable to have the process of apply | coating the sizing agent which contains at least to carbon fiber, and the process of mix | blending the carbon fiber with which the sizing agent was apply | coated to a thermoplastic resin. The carbon fiber to which the sizing agent is applied can be obtained by a process of applying the sizing agent to the carbon fiber.

  Further, the method of blending the carbon fiber coated with the sizing agent of the present invention with the thermoplastic resin is not limited, but a method of simultaneously melting and kneading the sizing agent coated carbon fiber of the present invention and the thermoplastic resin can be mentioned. By melting and kneading the carbon fiber coated with the sizing agent and the thermoplastic resin, the carbon fiber can be uniformly dispersed, and a carbon fiber reinforced composite material having good quality and excellent mechanical properties can be obtained. .

  In this invention, it is preferable that it is a carbon fiber reinforced thermoplastic resin composition which consists of 1-80 mass% of carbon fibers with which the sizing agent was apply | coated, and 20-99 mass% of thermoplastic resins.

  The melt kneading method is not particularly limited, and a known heat melt mixing apparatus can be used. Specifically, a single screw extruder, a twin screw extruder, a combination twin screw extruder, a kneader / ruder, or the like can be used. Especially, it is preferable to use a twin-screw extruder from a viewpoint of mixing force, More preferably, it is to use the twin-screw extruder which has two or more kneading zones.

  As the form when the carbon fiber coated with the sizing agent is introduced into the heating and melting mixing apparatus, either a continuous fiber form or a discontinuous fiber form cut to a specific length can be used. Carbon fiber reinforced with excellent mechanical properties as it is continuously fed into a melt-mixing device directly heated (direct roving), because carbon fiber breakage can be suppressed and the fiber length can be secured among carbon fiber reinforced composite materials. A composite material can be obtained. Moreover, since the process of cutting the carbon fiber can be omitted, productivity is improved.

  The carbon fiber reinforced thermoplastic resin composition of the present invention may contain other components other than those described above, depending on the application, etc., as long as the mechanical properties are not impaired, and fillers, additives, etc. May be included. As fillers or additives, inorganic fillers, flame retardants, conductivity imparting agents, crystal nucleating agents, ultraviolet absorbers, antioxidants, vibration damping agents, antibacterial agents, insect repellents, deodorants, coloring inhibitors, heat Stabilizers, mold release agents, antistatic agents, plasticizers, lubricants, colorants, pigments, foaming agents, coupling agents and the like can be mentioned.

  As an additive, the addition of a flame retardant is particularly preferably used for applications that require flame retardancy, and the addition of a conductivity imparting agent for applications that require electrical conductivity. Examples of the flame retardant include flame retardants such as halogen compounds, antimony compounds, phosphorus compounds, nitrogen compounds, silicone compounds, fluorine compounds, phenol compounds, and metal hydroxides. Among these, from the viewpoint of suppressing environmental burden, phosphorus compounds such as ammonium polyphosphate, polyphosphazene, phosphate, phosphonate, phosphinate, phosphine oxide, and red phosphorus can be preferably used.

  Examples of the conductivity imparting agent that can be used include carbon black, amorphous carbon powder, natural graphite powder, artificial graphite powder, expanded graphite powder, pitch microbeads, vapor-grown carbon fiber, and carbon nanotube.

  Since the sizing agent-coated carbon fiber in the present invention has high convergence, smoothness and good adhesion, the carbon fiber reinforced thermoplastic resin composition is used in the form of a molding material such as a pellet, a stampable sheet and a prepreg. can do. The most preferred molding material is pellets. Pellets are generally obtained by melt-kneading, extruding and pelletizing thermoplastic resin pellets and continuous carbon fibers or discontinuous carbon fibers cut to a specific length (chopped carbon fibers) in an extruder. It refers to what was given.

  Examples of the molding method of the molding material include injection molding (injection compression molding, gas assist injection molding, insert molding, etc.), blow molding, rotational molding, extrusion molding, press molding, transfer molding, and filament winding molding. Among these, injection molding is preferably used from the viewpoint of productivity. A carbon fiber reinforced composite material can be obtained by these molding methods.

  The carbon fiber reinforced composite material obtained from the prepreg of the present invention is used for computer structures such as aircraft structural members, windmill blades, automobile outer plates and IC trays and housings of notebook computers (housings), golf shafts, bats, It is preferably used for sports applications such as badminton and tennis rackets.

  Examples of uses of the carbon fiber reinforced composite material obtained by molding the carbon fiber reinforced thermoplastic resin composition of the present invention include, for example, personal computers, displays, OA equipment, mobile phones, portable information terminals, facsimile machines, compact disks, portable MDs, Enclosures of electrical and electronic equipment such as portable radio cassettes, PDAs (personal information terminals such as electronic notebooks), video cameras, digital still cameras, optical equipment, audio equipment, air conditioners, lighting equipment, entertainment equipment, toy goods, and other home appliances Various parts such as body and internal parts such as trays and chassis, building materials such as cases, mechanism parts, panels, motor parts, alternator terminals, alternator connectors, IC regulators, potentiometer bases for light deer, suspension parts, exhaust gas valves, etc. , Burning Relations, exhaust system or various intake system pipes, air intake nozzle snorkel, intake manifold, various arms, various frames, various hinges, various bearings, fuel pump, gasoline tank, CNG tank, engine coolant joint, carburetor main body, carburetor spacer , Exhaust gas sensor, cooling water sensor, oil temperature sensor, brake pad wear sensor, throttle position sensor, crankshaft position sensor, air flow meter, brake butt wear sensor, thermostat base for air conditioner, heating hot air flow control valve, radiator motor Brush holders, water pump impellers, turbine vanes, wiper motor parts, distributors, starters Switch, starter relay, transmission wire harness, window washer nozzle, air conditioner panel switch board, coil for fuel-related electromagnetic valve, connector for fuse, battery tray, AT bracket, headlamp support, pedal housing, handle, door beam, protector, chassis , Frame, armrest, horn terminal, step motor rotor, lamp socket, lamp reflector, lamp housing, brake piston, noise shield, radiator support, spare tire cover, seat shell, solenoid bobbin, engine oil filter, ignition device case, under cover , Scuff plate, pillar trim, propeller shaft, wheel, fender, fascia, van Automobiles, motorcycle related parts such as pars, bumper beams, bonnets, aero parts, platforms, cowl louvers, roofs, instrument panels, spoilers and various modules, parts and skins, landing gear pods, winglets, spoilers, edges, ladders Aircraft-related parts such as elevators, failings, ribs, members and outer plates, windmill blades, and the like. In particular, it is preferably used for aircraft members, windmill blades, automobile outer plates, casings of electronic devices, trays, chassis, and the like.

  EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not restrict | limited by these Examples.

(1) X-ray photoelectron spectroscopy of sizing agent-coated carbon fiber sizing agent surface In the present invention, the peak ratio of (a) and (b) on the sizing agent-coated carbon fiber sizing agent surface is expressed by AlKα _{1 , 2} by X-ray photoelectron spectroscopy according to the following procedure. Cut the sizing agent-coated carbon fiber to 20 mm, and spread and arrange it on a copper sample support. Then, use AlKα _1,2 as the X-ray source and keep the sample chamber at 1 × 10 ⁻⁸ Torr for measurement. It was. The photoelectron escape angle was 15 °. As correction of the peak accompanying charging during measurement, first, the binding energy value of the main peak of C _1s was adjusted to 286.1 eV. At this time, the peak area of C _1s was obtained by drawing a straight baseline in the range of 282 to 296 eV. Further, a linear base line of 282 to 296 eV obtained by calculating the area at the C _1s peak is defined as the origin (zero point) of the photoelectron intensity, and (b) the peak of the binding energy 286.1 eV attributed to the CO component is obtained. The height (cps: photoelectron intensity per unit time) and the height (cps) of the component having a binding energy of 284.6 eV attributed to (a) CHx, C—C, C = C are obtained, and (a) / ( b) was calculated.

Incidentally, when the peak of from (a) is large _(b), when combined binding energy of the main peak of _{C 1s} to _286.1, the peak of _{C 1s} does not fall within the scope of 282～296EV. In that case, after adjusting the binding energy value of the C _1s main peak to 284.6 eV, (a) / (b) was calculated by the above method.

(2) Cleaning of sizing agent of sizing agent-coated carbon fiber 2 g of sizing agent-coated carbon fiber was immersed in 50 ml of acetone and subjected to ultrasonic cleaning for 30 minutes three times. Subsequently, the substrate was immersed in 50 ml of methanol, subjected to ultrasonic cleaning for 30 minutes once and dried.

(3) X-ray photoelectron spectroscopy at 400 eV of sizing agent-coated carbon fiber In the present invention, the peak ratio of (a) and (b) on the sizing agent-coated carbon fiber surface is determined by X-ray photoelectron spectroscopy. It was determined according to the following procedure. The sizing agent-coated carbon fiber and the sizing agent-coated carbon fiber washed with the sizing agent are cut to 20 mm, spread and arranged on a copper sample support, and then Saga synchroton radiation is used as an X-ray source, and the excitation energy is 400 eV. It carried out in. The measurement was performed while keeping the inside of the sample chamber at 1 × 10 ⁻⁸ Torr. The photoelectron escape angle was 55 °. As correction of the peak accompanying charging during measurement, first, the binding energy value of the main peak of C _1s was adjusted to 286.1 eV. At this time, the peak area of C _1s was obtained by drawing a straight baseline in the range of 282 to 296 eV. Further, a linear base line of 282 to 296 eV obtained by calculating the area at the C _1s peak is defined as the origin (zero point) of the photoelectron intensity, and (b) the peak of the binding energy 286.1 eV attributed to the CO component is obtained. Obtain the height (cps: photoelectron intensity per unit time) and (a) the height (cps) of the component having a binding energy of 284.6 eV attributed to CHx, C—C, C = C. (B) was calculated.

Incidentally, when the peak of from (a) is large _(b), when combined binding energy of the main peak of _{C 1s} to _286.1, the peak of _{C 1s} does not fall within the scope of 282～296EV. In that case, after adjusting the binding energy value of the C _1s main peak to 284.6 eV, (a) / (b) was calculated by the above method.

(4) Strand tensile strength and elastic modulus of carbon fiber bundles Strand tensile strength and strand elastic modulus of carbon fiber bundles were determined according to the following procedure in accordance with the resin-impregnated strand test method of JIS-R-7608 (2004). . As the resin formulation, “Celoxide (registered trademark)” 2021P (manufactured by Daicel Chemical Industries) / 3 boron trifluoride monoethylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) / Acetone = 100/3/4 (part by mass) is used. As curing conditions, normal pressure, temperature of 125 ° C., and time of 30 minutes were used. Ten strands of the carbon fiber bundle were measured, and the average value was defined as the strand tensile strength and the strand elastic modulus.

(5) Surface oxygen concentration of carbon fiber (O / C)
The surface oxygen concentration (O / C) of the carbon fiber was determined by X-ray photoelectron spectroscopy according to the following procedure. First, the carbon fiber from which the dirt adhering to the surface with a solvent is removed is cut to about 20 mm and spread on a copper sample support. Next, the sample support was set in the sample chamber, and the inside of the sample chamber was kept at 1 × 10 ⁻⁸ Torr. Subsequently, AlKα ₁ and ₂ were used as the X-ray source, and the photoelectron escape angle was 90 °. In addition, the binding energy value of the C _1s main peak (peak top) was adjusted to 284.6 eV as a correction value for the peak accompanying charging during measurement. The C _1s peak area was determined by drawing a straight base line in the range of 282 to 296 eV. The O _1s peak area was determined by drawing a straight base line in the range of 528 to 540 eV. Here, the surface oxygen concentration is calculated as an atomic ratio by using a sensitivity correction value unique to the apparatus from the ratio of the O _1s peak area to the C _1s peak area. As the X-ray photoelectron spectroscopy apparatus, ESCA-1600 manufactured by ULVAC-PHI Co., Ltd. was used, and the sensitivity correction value unique to the apparatus was 2.33.

(6) Epoxy value of epoxy compound The epoxy value of the epoxy compound was determined by acid-base titration after dissolving the epoxy compound in N, N-dimethylformamide, opening the epoxy group with hydrochloric acid. In the present invention, the epoxy compound using this method corresponds to the aliphatic epoxy compound (A), the aromatic epoxy compound (D), and the epoxy compound (E) used for the thermosetting resin.

(7) Number of epoxy groups of epoxy compound The number of epoxy groups was determined by dividing the epoxy equivalent (unit: g / eq.) Calculated from the epoxy value measured in (6) by the number average molecular weight. The number average molecular weight was determined by GPC using dimethylformamide (0.01N-lithium bromide added) as a solvent. A measurement sample was prepared by dissolving 2 mg of an epoxy compound in 1 ml of a solvent. TSK-gelα3000 (manufactured by Tosoh Corporation) was used as a column, and calculation was performed using monodisperse polystyrene as a standard. A differential refractive index detector was used as the detector. In addition, in this invention, an aliphatic epoxy compound (A) and an aromatic epoxy compound (D) correspond as an epoxy compound using this method.

(8) Hydroxyl value of aliphatic epoxy compound (A) The hydroxyl value of aliphatic epoxy compound (A) is determined by dissolving aliphatic epoxy compound (A) in N, N-dimethylformamide and using acetic anhydride. Was acetylated and the resulting acetic acid was titrated with potassium hydroxide solution. Since the epoxy group is also titrated, it was corrected with the value of the epoxy value measured in (6).

(9) Measuring method of sizing adhesion amount Electricity set to a temperature of 450 ° C. in a nitrogen stream of 50 ml / min after weighing about 2 g of sizing adhesion carbon fiber bundle (W1) (reading to the fourth decimal place) Leave in a furnace (capacity 120 cm ³ ) for 15 minutes to completely pyrolyze the sizing agent. Then, the carbon fiber bundle after being transferred to a container in a dry nitrogen stream at 20 liters / minute and cooled for 15 minutes is weighed (W2) (read to the fourth decimal place), and the sizing adhesion amount is obtained by W1-W2. . A value obtained by converting this sizing adhesion amount into an amount with respect to 100 parts by mass of the carbon fiber bundle (rounded off to the third decimal place) was defined as a mass part of the adhering sizing agent. The measurement was performed twice, and the average value was defined as the mass part of the sizing agent.

(10) Measurement of interfacial shear strength (IFSS) The interfacial shear strength (IFSS) was measured by the following procedures (a) to (d).
(A) Preparation of resin 100 parts by mass of a bisphenol A type epoxy compound “jER (registered trademark)” 828 (manufactured by Mitsubishi Chemical Corporation) and 14.5 parts by mass of metaphenylenediamine (manufactured by Sigma-Aldrich Japan Co., Ltd.) Each was placed in a container. Thereafter, the mixture was heated at a temperature of 75 ° C. for 15 minutes in order to reduce the viscosity of the jER828 and dissolve the metaphenylenediamine. Then, both were mixed well and vacuum defoaming was performed at a temperature of 80 ° C. for about 15 minutes.
(B) Fixing the carbon fiber single yarn to the dedicated mold The single fiber was extracted from the carbon fiber bundle, and both ends were fixed with an adhesive in a state where a constant tension was applied to the single fiber in the longitudinal direction of the dumbbell mold. Then, in order to remove the water | moisture content adhering to carbon fiber and a mold, it vacuum-dried for 30 minutes or more at the temperature of 80 degreeC. The dumbbell mold was made of silicone rubber, and the shape of the cast part was a central part width of 5 mm, a length of 25 mm, both end part widths of 10 mm, and an overall length of 150 mm.
(C) From resin casting to curing The resin adjusted in the above procedure (b) is poured into the mold after the vacuum drying in the above step (b), and the temperature rising rate is 1.5 ° C. / The temperature rises to 75 ° C in minutes and is held for 2 hours, then rises to a temperature of 125 ° C at a heating rate of 1.5 ° C / min, held for 2 hours, and then reaches a temperature of 30 ° C at a cooling rate of 2.5 ° C / min. The temperature dropped. Then, it demolded and the test piece was obtained.
(D) Measurement of interfacial shear strength (IFSS) Tensile force was applied to the test piece obtained in the above procedure (c) in the fiber axis direction (longitudinal direction), and a tensile test was performed at a strain rate of 0.3% / second. For each 1% tension, the number of fiber breaks in the range of 22 mm in the center of the specimen is measured with a polarizing microscope, and the number of fiber breaks when the fiber breakage is saturated and no single fiber breakage occurs is N (pieces). It was. Using the number of fiber breaks, an average break fiber length la (μm) = 22 × 1000 (μm) / N (pieces) was calculated. Further, the critical fiber length lc (μm) = (4/3) × la (μm) was calculated from the average breaking fiber length la. In the present invention, the interfacial shear strength (IFSS), which is an index of the adhesive strength between the carbon fiber and the resin interface, was calculated by the following equation. σ is the strand tensile strength, and d is the diameter of the carbon fiber single yarn.
Interfacial shear strength IFSS (MPa) = σ (MPa) × d (μm) / (2 × lc) (μm)
IFSS values of 43 MPa or more were evaluated as ◎, 40 MPa or more and less than 43 MPa as ◯, 30 MPa or more and less than 40 MPa as Δ, and less than 30 MPa as x. ○ is a preferred range in the present invention.

(11) Evaluation of thermosetting resin (prepreg, carbon fiber reinforced composite material) Pre-preg quality As an index of carbon fiber smoothness, prepreg irregularities were confirmed. Good ones with few irregularities were marked with ○, those with undulations were marked with Δ, and those with gaps between carbon fiber bundles were marked with ×. In the present invention, ◯ is a preferred range.
B. 0 ° Tensile Strength Utilization Rate (a) Definition of 0 ° of Carbon Fiber Reinforced Composite Material As described in JIS K7017 (1999), the fiber direction of the unidirectional fiber reinforced composite material is the axial direction, and the axial direction is 0. The axis was defined as the ° axis, and the direction perpendicular to the axis was defined as 90 °.
(B) Measurement of 0 ° tensile strength of carbon fiber reinforced composite material Cut unidirectional prepreg within 24 hours after preparation into a predetermined size, and stack 6 sheets in one direction, then vacuum bag and autoclave It was cured at a temperature of 180 ° C. and a pressure of 6 kgf / cm ² for 2 hours to obtain a unidirectional reinforcing material (carbon fiber reinforced composite material). The unidirectional reinforcing material was cut into a width of 12.7 mm and a length of 230 mm, and a glass fiber reinforced plastic tab having a length of 1.2 mm and a length of 50 mm was bonded to both ends to obtain a test piece. The test piece thus obtained was subjected to a tensile test at a crosshead speed of 1.27 mm / min using an Instron universal testing machine.

In the present invention, the value obtained by dividing the 0 ° tensile strength value (c) MPa by the strand strength value obtained in (4) was used as the strength utilization factor (%), and the following formula was obtained.
Strength utilization rate = tensile strength / ((CF basis weight / 190) × Vf / 100 × strand strength) × 100
CF basis weight = 190 g / m ²
Vf = 56%
A strength utilization rate of 83% or more was evaluated as ◎, 80% or more and less than 83% as ７８, 78% or more and less than 80% as Δ, and less than 78% as ×. ◎ and ○ are preferable ranges in the present invention.

(12) Evaluation of thermoplastic resin (processability, injection-molded product) Supplyability of cut sizing agent-coated carbon fiber As an index of convergence, sizing agent-coated carbon fiber cut to ¼ inch was supplied from a side feeder to a TEX-30α type twin screw extruder of Nippon Steel Works. Evaluation was made based on the availability of time. As a result, the case where there was no problem in supplyability was indicated by ◯, the case where some bridging due to poor biting was observed at the time of supply was indicated by Δ, and the case where bridges were frequently observed at the time of supply was indicated by ×. In the present invention, ○ is a preferred range.
B. Bending strength A bending strength test piece having a length of 130 ± 1 mm and a width of 25 ± 0.2 mm was cut out from the obtained injection molded product. According to the test method specified in ASTM D-790 (2004), using a three-point bending test jig (indenter 10 mm, fulcrum 10 mm), the support span is set to 100 mm, and the bending strength is measured at a crosshead speed of 5.3 mm / min. did. In this example, “Instron (registered trademark)” universal testing machine 4201 type (manufactured by Instron) was used as a testing machine. The number of measurements was n = 5, and the average value was the bending strength.

  An average bending strength of 230 MPa or more was rated as ◎, 220 MPa or more and less than 230 MPa as ○, 215 MPa or more and less than 220 MPa as Δ, and less than 215 MPa as x. ◎ and ○ are preferable ranges in the present invention.

The materials and components used in each example and each comparative example are as follows. In addition, (B) component showed the reference example and (C) component showed the detail in the text.
-(A) component (aliphatic epoxy compound): A-1 to A-2
A-1: “Denacol (registered trademark)” EX-611 (manufactured by Nagase ChemteX Corporation)
Sorbitol polyglycidyl ether Epoxy value: 6.0 meq. / G, hydroxyl value: 3.8 meq / g,
Number of epoxy groups: 4
A-2: “Denacol (registered trademark)” EX-521 (manufactured by Nagase ChemteX Corporation)
Polyglycerin polyglycidyl ether Epoxy value: 5.5 meq. / G, hydroxyl value: 2.58 meq / g,
Number of epoxy groups: 6.3
A-3: “Denacol (registered trademark)” EX-810 (manufactured by Nagase ChemteX Corporation)
Diglycidyl ether of ethylene glycol Epoxy value: 8.9 meq. / G, hydroxyl value: 0 meq / g, number of epoxy groups: 2
-Component (D) (aromatic epoxy compound): D-1, D-2
D-1: “jER (registered trademark)” 828 (manufactured by Mitsubishi Chemical Corporation)
Diglycidyl ether of bisphenol A Epoxy value: 5.3 meq. / G, number of epoxy groups: 2
D-2: “jER (registered trademark)” 807 (manufactured by Mitsubishi Chemical Corporation)
Diglycidyl ether of bisphenol F Epoxy value: 5.6 meq. / G, number of epoxy groups: 2
-(E) component: E-1, D-2
E-1: Tetraglycidyldiaminodiphenylmethane, “Sumiepoxy (registered trademark)” ELM434 (manufactured by Sumitomo Chemical Co., Ltd.)
Epoxy value: 8.3 meq. / G
E-2: “jER (registered trademark)” 828 (manufactured by Mitsubishi Chemical Corporation)
Diglycidyl ether of bisphenol A Epoxy value: 5.3 meq. / G
-(F) component:
F-1: “Seika Cure (registered trademark)” S (4,4′-diaminodiphenyl sulfone, manufactured by Wakayama Seika Co., Ltd.)
・ (G) component (thermoplastic resin)
G-1: Polyarylene sulfide resin Polyphenylene sulfide (PPS) resin pellet: “Torelina (registered trademark)” M2888 (manufactured by Toray Industries, Inc.)
Others “Sumika Excel (registered trademark)” 5003P (polyethersulfone, manufactured by Sumitomo Chemical Co., Ltd.).

(Reference Example 1)
The condensate (B-1) was synthesized according to a conventional method. After adding ethylene oxide to bisphenol A with a potassium hydroxide catalyst, the catalyst was treated to obtain an ethylene oxide (2 mol) adduct of bisphenol A. Into a 1 L flask equipped with a stirrer, stirring blade, nitrogen seal, and rectifying column, 2 mol of the above-mentioned ethylene oxide adduct of bisphenol A, 1.5 mol of maleic acid and 0.5 mol of sebacic acid were charged. The mixture was heated and stirred at 160 ° C. for 4 hours to distill off the water produced.

(Reference Example 2)
The condensate (B-2) was synthesized according to a conventional method. After propylene oxide was added to bisphenol A with a potassium hydroxide catalyst, the catalyst was treated to obtain a propylene oxide (2 mol) adduct of bisphenol A. In a 1 L flask equipped with a stirrer, a stirring blade, a nitrogen seal, and a rectifying column, 1.5 mol of propylene oxide adduct of bisphenol A and 1.5 mol of fumaric acid, 0.5 mol of diethylene glycolose, adipic acid 0 .5 mol was charged, and nitrogen was blown into the liquid while stirring at 160 ° C. for 4 hours to distill off the water produced.

(Reference Example 3)
The condensate (B-3) was synthesized according to a conventional method. After propylene oxide and ethylene oxide were added to bisphenol A with a potassium hydroxide catalyst, the catalyst was treated to obtain a random adduct of bisphenol A ethylene oxide (2 mol) and propylene oxide (2 mol). Into a 1 L flask equipped with a stirrer, stirring blade, nitrogen seal, and rectifying column, 1.0 mol of the above bisphenol A ethylene oxide, propylene oxide random adduct and 1.0 mol of maleic acid were charged, and nitrogen was introduced into the liquid. While blowing, the mixture was heated and stirred at 160 ° C. for 4 hours to distill off the generated water.

Example 1
This example comprises the following I step, II step and III step.
-Step I: Process for producing carbon fiber as a raw material A copolymer composed of 99 mol% acrylonitrile and 1 mol% itaconic acid is dry-wet spun, fired, total number of filaments 24,000, total fineness 1 , Tex, 1.8 specific gravity, strand tensile strength of 5.9 GPa, and strand tensile elastic modulus of 295 GPa were obtained. Next, the carbon fiber was subjected to electrolytic surface treatment with an aqueous solution of ammonium hydrogen carbonate having a concentration of 0.1 mol / l as an electrolytic solution at an electric quantity of 80 coulomb per gram of carbon fiber. The carbon fiber subjected to the electrolytic surface treatment was subsequently washed with water and dried in heated air at a temperature of 150 ° C. to obtain a carbon fiber as a raw material. At this time, the surface oxygen concentration O / C was 0.15, the surface carboxyl group concentration COOH / C was 0.005, and the surface hydroxyl group concentration COH / C was 0.018. The surface roughness (Ra) of the carbon fiber at this time was 3.0 nm.
Step II: Step of attaching sizing agent to carbon fiber (B-1) synthesized in Reference Example 1 as a condensate (B) component, polyoxyethylene (C) as a nonionic surfactant (C) component 70 mol) After preparing a water-dispersed emulsion consisting of styrenated (5 mol) cumylphenol, an aqueous solution of 52 parts by mass of (A-2) is prepared as the aliphatic epoxy compound (A), and both are mixed. A sizing solution was prepared.

After this sizing agent was applied to the carbon fiber surface-treated by the dipping method, heat treatment was performed at a temperature of 210 ° C. for 75 seconds to obtain a sizing agent-coated carbon fiber bundle. The adhesion amount of the sizing agent was adjusted to 0.6% by mass with respect to the sizing agent-coated carbon fiber. Subsequently, X-ray photoelectron spectroscopy measurement on the surface of the sizing agent, interfacial shear strength (IFSS) of the carbon fiber coated with the sizing agent, the amount of the aliphatic epoxy compound (A) eluted from the carbon fiber coated with the sizing agent ((A -2)) was measured. The results are summarized in Table 1-1. As a result, it was confirmed that both the chemical composition of the sizing agent surface and the elution amount of the aliphatic epoxy compound (A) were as expected. Moreover, it turned out that the adhesiveness measured by IFSS is also high.
-Step III: Preparation, molding and evaluation of prepreg After mixing and dissolving 10 parts by weight of Sumika Excel 5003P in 80 parts by weight of Sumiepoxy ELM434 and 20 parts by weight of jER828 in a kneading apparatus, 40 parts by mass of Seikacure S (4,4′-diaminodiphenylsulfone) was kneaded to prepare an epoxy resin composition for a carbon fiber reinforced composite material.

The obtained epoxy resin composition was coated on a release paper with a resin basis weight of 52 g / m ² using a knife coater to prepare a resin film. This resin film is superposed on both sides of a sizing agent-coated carbon fiber (weight per unit area 190 g / m ² ) aligned in one direction, and a heat roll is used to heat and press at 100 ° C. and 1 atm. Was impregnated into carbon fiber coated with a sizing agent to obtain a prepreg. The smoothness of the carbon fiber was very good, and the flatness of the prepreg was also good. Subsequently, an initial 0 ° tensile test was performed. The results are shown in Table 1-1. The 0 ° tensile strength utilization rate was high.

(Example 2)
-Step I: Step of producing carbon fiber as a raw material The same as in Example 1.
Step II: A step of attaching a sizing agent to carbon fiber (B-1) as a condensate (B) component, polyoxyethylene (70 mol) styrenation as a nonionic surfactant (C) component ( 5 mol) In addition to cumylphenol, after preparing an aqueous dispersion emulsion comprising (D-1) as the aromatic epoxy compound (D) component, an aqueous solution comprising (A-2) as the aliphatic epoxy compound (A) Was prepared, and both were mixed to prepare a sizing solution.

Subsequently, sizing agent-coated carbon fibers were obtained and evaluated in the same manner as in Example 1. As shown in Table 1-1, it was found that both the chemical composition of the sizing agent surface and the elution amount of the aliphatic epoxy compound (A) were as expected, and the adhesiveness measured by IFSS was sufficiently high.
Step III: Preparation, molding and evaluation of prepreg A prepreg was prepared, molded and evaluated in the same manner as in Example 1. It was found that the quality of the obtained prepreg was good and the 0 ° tensile strength utilization rate was sufficiently high. The results are shown in Table 1-1.

(Examples 3 and 5)
-Step I: Step of producing carbon fiber as a raw material The same as in Example 1.
Step II: Step of attaching sizing agent to carbon fiber Sizing agent-coated carbon in the same manner as in Example 1 except that (B-2) and (B-3) were used as the condensate (B). Fibers were obtained and evaluated. As shown in Table 1-1, it was found that both the chemical composition of the sizing agent surface and the elution amount of the aliphatic epoxy compound (A) were as expected, and the adhesiveness measured by IFSS was also high.
Step III: Preparation, molding and evaluation of prepreg A prepreg was prepared, molded and evaluated in the same manner as in Example 1. It was found that the quality of the obtained prepreg was very good, and the initial 0 ° tensile strength utilization rate was high. The results are shown in Table 1-1.

(Examples 4 and 6)
-Step I: Step of producing carbon fiber as a raw material The same as in Example 1.
Step II: Step of attaching sizing agent to carbon fiber Sizing agent-coated carbon in the same manner as in Example 2 except that (B-2) and (B-3) were used as the condensate (B). Fibers were obtained and evaluated. As shown in Table 1-1, it was found that both the chemical composition of the sizing agent surface and the elution amount of the aliphatic epoxy compound (A) were as expected, and the adhesiveness measured by IFSS was sufficiently high.
Step III: Preparation, molding and evaluation of prepreg A prepreg was prepared, molded and evaluated in the same manner as in Example 1. It was found that the quality of the obtained prepreg was good and the initial 0 ° tensile strength utilization rate was sufficiently high. The results are shown in Table 1-1.

(Example 7)
-Step I: Step of producing carbon fiber as a raw material The same as in Example 1.
-Step II: Step of attaching sizing agent to carbon fiber Except for changing the amount of sizing agent attached to 1.0% by mass, a sizing agent-coated carbon fiber was obtained and evaluated in the same manner as in Example 1. It was. As shown in Table 1-1, it was found that both the chemical composition of the sizing agent surface and the elution amount of the aliphatic epoxy compound (A) were as expected, and the adhesiveness measured by IFSS was also high.
Step III: Preparation, molding and evaluation of prepreg A prepreg was prepared, molded and evaluated in the same manner as in Example 1. It was found that the quality of the obtained prepreg was good and the initial 0 ° tensile strength utilization rate was high. The results are shown in Table 1-1.

(Example 8)
-Step I: Step of producing carbon fiber as a raw material The same as in Example 1.
-Step II: Step of attaching sizing agent to carbon fiber (S) Except for changing to (D-2) as component (D), sizing agent-coated carbon fiber was obtained and evaluated in the same manner as in Example 2. It was. As shown in Table 1-1, it was found that both the chemical composition of the sizing agent surface and the elution amount of the aliphatic epoxy compound (A) were as expected, and the adhesiveness measured by IFSS was sufficiently high.
Step III: Preparation, molding and evaluation of prepreg A prepreg was prepared, molded and evaluated in the same manner as in Example 1. It was found that the quality of the obtained prepreg was good and the initial 0 ° tensile strength utilization rate was sufficiently high. The results are shown in Table 1-1.

Example 9
-Step I: Step of producing carbon fiber as a raw material The same as in Example 1.
-Step II: Step of attaching sizing agent to carbon fiber (A) Except for changing to (A-1) as component, sizing agent-coated carbon fiber was obtained and evaluated in the same manner as in Example 2. It was. As shown in Table 1-1, it was found that both the chemical composition of the sizing agent surface and the elution amount of the aliphatic epoxy compound (A) were as expected, and the adhesiveness measured by IFSS was sufficiently high.
Step III: Preparation, molding and evaluation of prepreg A prepreg was prepared, molded and evaluated in the same manner as in Example 1. It was found that the quality of the obtained prepreg was good and the initial 0 ° tensile strength utilization rate was sufficiently high. The results are shown in Table 1-1.

(Example 10)
-Step I: Step of producing carbon fiber as a raw material The same as in Example 1.
-Step II: Step of attaching sizing agent to carbon fiber (A) Except for changing to (A-3) as a component, sizing agent-coated carbon fiber was obtained and evaluated in the same manner as in Example 2. It was. As shown in Table 1-1, it was found that both the chemical composition of the sizing agent surface and the elution amount of the aliphatic epoxy compound (A) were as expected, and the adhesiveness measured by IFSS was also high.
Step III: Preparation, molding and evaluation of prepreg A prepreg was prepared, molded and evaluated in the same manner as in Example 1. It was found that the quality of the obtained prepreg was good and the initial 0 ° tensile strength utilization rate was high. The results are shown in Table 1-1.

(Example 11)
-Step I: Step of producing carbon fiber as a raw material The same as in Example 1.
Step II: Step of attaching sizing agent to carbon fiber (A), (B), (C) Except for changing the ratio of the components, sizing agent-coated carbon fiber is obtained in the same manner as in Example 1. And evaluated. As shown in Table 1-1, it was found that both the chemical composition of the sizing agent surface and the elution amount of the aliphatic epoxy compound (A) were as expected, and the adhesiveness measured by IFSS was sufficiently high.
Step III: Preparation, molding and evaluation of prepreg A prepreg was prepared, molded and evaluated in the same manner as in Example 1. The quality of the obtained prepreg was within a preferable range in the present invention, but was slightly lower than that in Example 1. In the present invention, it was found that the initial 0 ° tensile strength utilization rate was sufficiently high. The results are shown in Table 1-1.

(Comparative Example 1)
-Step I: Step of producing carbon fiber as a raw material The same as in Example 1.
-Step II: Step of attaching sizing agent to carbon fiber The same method as in Example 1 except that only the component (A) was used without using the components (B) and (C) as the sizing agent. A sizing agent-coated carbon fiber was obtained. Subsequently, X-ray photoelectron spectroscopy measurement of the sizing agent surface, interfacial shear strength (IFSS) of the sizing agent-coated carbon fiber, and the amount of the aliphatic epoxy compound (A) eluted from the sizing agent-coated carbon fiber were measured. Component of binding energy (284.6 eV) attributed to (a) CHx, C—C, C = C of C _1s inner shell spectrum measured by X-ray photoelectron spectroscopy on the sizing agent surface at a photoelectron escape angle of 15 ° The ratio (a) / (b) of the height (cps) of the component (b) and the height (cps) of the component of the binding energy (286.1 eV) attributed to C—O is smaller than 0.50. Was out of range.
Step III: Preparation, molding and evaluation of prepreg A prepreg was prepared, molded and evaluated in the same manner as in Example 1. It was found that the quality of the prepreg was slightly low.

(Comparative Example 2)
-Step I: Step of producing carbon fiber as a raw material The same as in Example 1.
-Step II: Step of attaching sizing agent to carbon fiber As in Example 2, except that the ratio of components (A), (B), and (D) as sizing agent was changed as shown in Table 1-2. The sizing agent-coated carbon fiber was obtained by Subsequently, X-ray photoelectron spectroscopy measurement of the sizing agent surface, interfacial shear strength (IFSS) of the sizing agent-coated carbon fiber, and the amount of the aliphatic epoxy compound (A) eluted from the sizing agent-coated carbon fiber were measured. Component of binding energy (284.6 eV) attributed to (a) CHx, C—C, C = C of C _1s inner shell spectrum measured by X-ray photoelectron spectroscopy on the sizing agent surface at a photoelectron escape angle of 15 ° The ratio (a) / (b) of the height (cps) of the component (b) and the height (cps) of the component of the binding energy (286.1 eV) attributed to C—O is smaller than 0.90. Was out of range. Moreover, it turned out that the adhesiveness measured by IFSS is low.
Step III: Preparation, molding and evaluation of prepreg A prepreg was prepared, molded and evaluated in the same manner as in Example 1. Although the quality of the prepreg was good, it was found that the 0 ° tensile strength utilization rate was low.

(Comparative Example 3)
-Step I: Step of producing carbon fiber as a raw material The same as in Example 1.
Step II: Step of attaching sizing agent to carbon fiber The same method as in Example 2 except that (B) component was not used as the sizing agent, and (A), (C), and (D) were used. The sizing agent-coated carbon fiber was obtained and evaluated. As shown in Table 1-2, it was found that both the chemical composition of the sizing agent surface and the elution amount of the aliphatic epoxy compound (A) were as expected, and the adhesiveness measured by IFSS was sufficiently high.
Step III: Preparation, molding and evaluation of prepreg A prepreg was prepared, molded and evaluated in the same manner as in Example 1. Although the 0 ° tensile strength utilization rate was sufficiently high, the prepreg quality was found to be slightly low.

(Comparative Example 4)
-Step I: Step of producing carbon fiber as a raw material The same as in Example 1.
Step II: A step of attaching a sizing agent to carbon fiber The same method as in Example 2 except that (B), (C), and (D) were not used as the sizing agent, but the component (A) was not used. A carbon fiber coated with a sizing agent was obtained. Subsequently, X-ray photoelectron spectroscopy measurement of the sizing agent surface, interfacial shear strength (IFSS) of the sizing agent-coated carbon fiber, and the amount of the aliphatic epoxy compound (A) eluted from the sizing agent-coated carbon fiber were measured. Component of binding energy (284.6 eV) attributed to (a) CHx, C—C, C = C of C _1s inner shell spectrum measured by X-ray photoelectron spectroscopy on the sizing agent surface at a photoelectron escape angle of 15 ° The ratio (a) / (b) of the height (cps) of the component (b) and the height (cps) of the component of the binding energy (286.1 eV) attributed to C—O is greater than 0.90. Was out of range. Moreover, it turned out that the adhesiveness measured by IFSS is low.
Step III: Preparation, molding and evaluation of prepreg A prepreg was prepared, molded and evaluated in the same manner as in Example 1. Although the quality of the prepreg was good, it was found that the 0 ° tensile strength utilization rate was low.

(Comparative Example 5)
-Step I: Step of producing carbon fiber as a raw material The same as in Example 1.
-Step II: Step of attaching sizing agent to carbon fiber (A) After preparing the aqueous solution of (A-2) as a component and applying it to the carbon fiber surface-treated by the dipping method, at a temperature of 210 ° C Heat treatment was performed for 75 seconds to obtain a sizing agent-coated carbon fiber bundle. The adhesion amount of the sizing agent was adjusted to 0.30 parts by mass with respect to 100 parts by mass of the surface-treated carbon fiber. Then, the water-dispersed emulsion which consists of (B-1) and (C) component as (B) component, and (D-1) as (D) component was prepared. After this sizing agent was applied to the carbon fiber coated with the component (A) by the dipping method, heat treatment was performed at a temperature of 210 ° C. for 75 seconds to obtain a sizing agent-coated carbon fiber bundle. The adhesion amount of the sizing agent adhered later was adjusted to 0.30 part by mass with respect to 100 parts by mass of the surface-treated carbon fiber. Subsequently, X-ray photoelectron spectroscopy measurement of the sizing agent surface, interfacial shear strength (IFSS) of the sizing agent-coated carbon fiber, and the amount of the aliphatic epoxy compound (A) eluted from the sizing agent-coated carbon fiber were measured. Component of binding energy (284.6 eV) attributed to (a) CHx, C—C, C = C of C _1s inner shell spectrum measured by X-ray photoelectron spectroscopy on the sizing agent surface at a photoelectron escape angle of 15 ° The ratio (a) / (b) of the height (cps) of the component (b) and the height (cps) of the component of the binding energy (286.1 eV) attributed to C—O is greater than 0.90. Was out of range. Moreover, it turned out that the adhesiveness measured by IFSS is high enough.
Step III: Preparation, molding and evaluation of prepreg A prepreg was prepared, molded and evaluated in the same manner as in Example 1. The tensile strength utilization rate was not a sufficient value.

(Example 12)
-Step I: Step of producing carbon fiber as a raw material The same as in Example 1.
Step II: Step of attaching sizing agent to carbon fiber The same procedure as in Example 1 was performed.
-Step III: Cutting step of carbon fiber coated with sizing agent The carbon fiber coated with the sizing agent obtained in Step II was cut into 1/4 inch with a cartridge cutter.
-Step IV: Extrusion process Using a TEX-30α type twin screw extruder (screw diameter 30 mm, L / D = 32), PPS resin pellets were supplied from the main hopper, and then The carbon fiber coated with the sizing agent cut in the previous step was supplied from the downstream side hopper, kneaded sufficiently at a barrel temperature of 320 ° C. and a rotation speed of 150 rpm, and further deaerated from the downstream vacuum vent. The supply was adjusted by a weight feeder so that the carbon fiber coated with the sizing agent was 10 parts by mass with respect to 90 parts by mass of the PPS resin pellets. The molten resin was discharged from a die port (diameter 5 mm), and the obtained strand was cooled and then cut with a cutter to obtain a pellet-shaped molding material. In addition, as shown in Table 2, there was no problem in the supply property of the carbon fiber coated with the sizing agent.
-V step: injection molding step:
Using the J350EIII type injection molding machine manufactured by Nippon Steel Works, the pellet-shaped molding material obtained in the extrusion process was molded into a specimen for characteristic evaluation at a cylinder temperature of 330 ° C. and a mold temperature of 80 ° C. . The obtained test piece was subjected to a characteristic evaluation test after being left in a constant temperature and humidity chamber adjusted to a temperature of 23 ° C. and 50% RH for 24 hours. Next, the obtained test piece for property evaluation was evaluated according to the above-described injection molded product evaluation method. The results are summarized in Table 2. As a result, it was found that the bending strength has high mechanical properties.

(Example 13)
-Step I: Step of producing carbon fiber as a raw material The same as in Example 1.
Step II: Step of attaching a sizing agent to carbon fiber The same procedure as in Example 2 was performed.
-Steps III to V:
A test piece for property evaluation was molded in the same manner as in Example 1. Next, the obtained test piece for property evaluation was evaluated according to the above-described injection molded product evaluation method. As a result, as shown in Table 2, it was found that there was no problem in the supply property of the carbon fiber coated with the sizing agent, the bending strength was high, and the mechanical properties were sufficiently high.

(Comparative Example 6)
-Step I: Step of producing carbon fiber as a raw material The same as in Example 1.
Step II: Step of attaching a sizing agent to carbon fiber The same procedure as in Comparative Example 1 was performed.
-Steps III to V:
A test piece for property evaluation was molded in the same manner as in Example 1. Next, the obtained test piece for property evaluation was evaluated according to the above-described injection molded product evaluation method. As a result, a slight bridge was observed when the sizing agent-coated carbon fiber was supplied to the biaxial kneader. Further, it was found that the bending strength was as shown in Table 2 and the mechanical properties were not sufficient.

(Comparative Example 7)
-Step I: Step of producing carbon fiber as a raw material The same as in Example 1.
Step II: Step of attaching a sizing agent to carbon fiber The same procedure as in Comparative Example 4 was performed.
-Steps III to V:
A test piece for property evaluation was molded in the same manner as in Example 1. Next, the obtained test piece for property evaluation was evaluated according to the above-described injection molded product evaluation method. As a result, as shown in Table 2, it was found that there was no problem in the availability of the carbon fiber coated with the sizing agent, but the mechanical properties were not sufficient.

(Comparative Example 8)
-Step I: Step of producing carbon fiber as a raw material The same as in Example 1.
Step II: Step of adhering sizing agent to carbon fiber Same as Comparative Example 5.
-Steps III to V:
A test piece for property evaluation was molded in the same manner as in Example 1. Next, the obtained test piece for property evaluation was evaluated according to the above-described injection molded product evaluation method. As a result, as shown in Table 2, it was found that there was no problem in the supply property of the sizing agent-coated carbon fiber, but the bending strength was slightly low.

(Example 14)
2 g of the sizing agent-coated carbon fiber obtained in Example 1 was immersed in 50 ml of acetone and subjected to ultrasonic cleaning for 30 minutes three times. Subsequently, the substrate was immersed in 50 ml of methanol, subjected to ultrasonic cleaning for 30 minutes once and dried. Table 3 shows the amount of sizing agent adhesion remaining after washing.

  Subsequently, the sizing agent surface of the sizing agent-coated carbon fiber before washing, and the sizing agent-coated carbon fiber sizing agent surface obtained by washing were assigned to (b) CO component by X-ray photoelectron spectroscopy at 400 eV. The peak height of the binding energy of 286.1 eV and the height (cps) of the component of the binding energy of 284.6 eV attributed to (a) CHx, C-C, C = C are obtained, and (I) before washing (A) / (b) on the sizing agent surface of the sizing agent-coated carbon fiber, (II) (a) / (b) on the sizing agent surface of the sizing agent-coated carbon fiber after washing. (I) and (II) / (I) were as shown in Table 3.

(Comparative Example 9)
(A) CHx, C-C of C1s inner-shell spectrum by X-ray photoelectron spectroscopy using 400 eV X-rays before and after cleaning using the sizing agent-coated carbon fiber obtained in Comparative Example 1 as in Example 14. , The height (cps) of the component of the binding energy (284.6 eV) attributed to C = C, and (b) the height (cps) of the component of the binding energy (286.1 eV) attributed to C—O. The ratio (a) / (b) was obtained. The results are shown in Table 3, and it was found that (II / I) was large and no grading structure was obtained in the sizing agent.

(Comparative Example 10)
(A) CHx, C-C of C1s inner-shell spectrum by X-ray photoelectron spectroscopy using 400 eV X-rays before and after washing using the sizing agent-coated carbon fiber obtained in Comparative Example 4 as in Example 14. , The height (cps) of the component of the binding energy (284.6 eV) attributed to C = C, and (b) the height (cps) of the component of the binding energy (286.1 eV) attributed to C—O. The ratio (a) / (b) was obtained. The results are shown in Table 3, and it was found that (II / I) was large and no grading structure was obtained in the sizing agent.

(Comparative Example 11)
(A) CHx, C-C of C1s inner shell spectrum by X-ray photoelectron spectroscopy using 400 eV X-rays before and after cleaning using the sizing agent-coated carbon fiber obtained in Comparative Example 5 as in Example 14. , The height (cps) of the component of the binding energy (284.6 eV) attributed to C = C, and (b) the height (cps) of the component of the binding energy (286.1 eV) attributed to C—O. The ratio (a) / (b) was obtained. The results are shown in Table 3, and it was found that (II / I) was small.

  Since the sizing agent-coated carbon fiber and the method for producing the sizing agent-coated carbon fiber of the present invention have excellent adhesiveness and the convergence and smoothness of the sizing agent-coated carbon fiber, it can be applied to a prepreg or a carbon fiber-reinforced thermoplastic resin. Suitable for processing. Further, the prepreg, carbon fiber reinforced thermoplastic resin of the present invention and the carbon fiber reinforced composite material comprising the prepreg are lightweight, yet have excellent strength and elastic modulus. Therefore, aircraft members, spacecraft members, automobile members, ship members, civil engineering architecture It can be suitably used in many fields such as materials and sports equipment.

Claims (16)

At least (A) a carbon fiber coated with a sizing agent containing ~ a (C), the C _1s inner shell spectrum measured by X-ray photoelectron spectroscopy sizing agent surface photoelectron escape angle 15 ° (a) CHx , C—C, the height (cps) of the component of the bond energy (284.6 eV) attributed to C = C and (b) the height of the component of the bond energy (286.1 eV) attributed to C—O A sizing agent-coated carbon fiber having a ratio (a) / (b) of (cps) of 0.50 to 0.90.
(A) The following (i) or (ii) aliphatic epoxy compound (B) Condensation product of unsaturated dibasic acid and alkylene oxide adduct of bisphenol (C) Nonionic surfactant containing an aromatic ring
(I) An aliphatic epoxy compound having an epoxy value of 2.0 to 8.0 meq / g, a hydroxyl value of 2.0 to 5.0 meq / g, and having two or more epoxy groups in the molecule
(Ii) Aliphatic epoxy which is a glycidyl ether type epoxy compound obtained by reaction of one selected from glycerol, diglycerol, polyglycerol, trimethylolpropane, pentaerythritol, sorbitol, and arabitol with epichlorohydrin Compound The sizing agent-coated carbon fiber according to claim 1, wherein an interfacial shear strength between the single fiber of the sizing agent-coated carbon fiber and the epoxy resin is 40 MPa or more. The ratio (A) / (B) of the condensate (B) of the aliphatic epoxy compound (A), unsaturated dibasic acid and alkylene oxide adduct of bisphenols contained in the sizing agent is 52 / 48-80 / Sizing agent application | coating carbon fiber of Claim 1 or 2 which is 20. When the sizing agent applied by sonicating the sizing agent-coated fiber with an acetonitrile / chloroform mixed solvent was eluted, the ratio of the eluted aliphatic epoxy compound (A) was 100 parts by mass of the sizing agent-coated carbon fiber. Sizing agent application | coating carbon fiber in any one of Claims 1-3 which is 0.3 mass part or less with respect to this. The sizing agent-coated carbon fiber is assigned to (a) CHx, C-C, C = C in the C _1s core spectrum measured at a photoelectron escape angle of 55 ° by X-ray photoelectron spectroscopy using 400 eV X-rays. Between the height (cps) of the component of the binding energy (284.6 eV) and the height (cps) of the component of the binding energy (286.1 eV) attributed to C—O (a) Sizing agent application | coating carbon fiber in any one of Claims 1-4 with which the value of (I) and (II) calculated | required from / (b) satisfy | fills the relationship of (III).
(I) Value of (a) / (b) on the surface of the sizing agent-coated carbon fiber before sonication (II) Sizing agent adhesion by sonicating the sizing agent-coated carbon fiber in an acetone solvent (A) / (b) value (III) 0.50 ≦ (I) ≦ 0.90 and 0.6 <on the surface of the sizing agent-coated carbon fiber washed to 0.09 to 0.20 mass%. (II) / (I) <1.0 Sizing agent application | coating carbon fiber in any one of Claims 1-5 containing an aromatic epoxy compound (D) in the said sizing agent. Sizing agent application | coating carbon fiber of Claim 6 whose aromatic epoxy compound (D) is a bisphenol A type epoxy compound or a bisphenol F type epoxy compound. Component of binding energy (284.6 eV) attributed to (a) CHx, C—C, C = C of C _1s inner shell spectrum measured by X-ray photoelectron spectroscopy on the sizing agent surface at a photoelectron escape angle of 15 ° The ratio (a) / (b) of the height (cps) of the component (b) and the height (cps) of the binding energy (286.1 eV) attributed to C—O is 0.50 to 0.90. A method for producing a sizing agent-coated carbon fiber in which a sizing agent containing at least (A) to (C) is applied to carbon fiber, a water emulsion containing at least (B), and a composition containing at least (A) A method for producing a sizing agent-coated carbon fiber, comprising: applying a sizing agent-containing liquid mixed with a product to carbon fiber and then heat-treating the solution in a temperature range of 160 to 260 ° C for 30 to 600 seconds.
(A) Aliphatic epoxy compound (B) Condensation product of unsaturated dibasic acid and alkylene oxide adduct of bisphenols (C) Nonionic surfactant containing an aromatic ring The manufacturing method of the sizing agent application | coating carbon fiber of Claim 8 which apply | coats the said sizing agent containing liquid after carrying out the liquid phase electrolytic oxidation in the alkaline electrolyte. Prepreg and sizing agent applying carbon fiber according to claim 1, characterized in that it comprises a thermosetting resin. The prepreg according to claim 10, wherein the thermosetting resin contains an epoxy compound (E) and a latent curing agent (F). A carbon fiber reinforced thermoplastic resin composition comprising the sizing agent-coated carbon fiber according to any one of claims 1 to 7 and a thermoplastic resin. One or more thermoplastic resins selected from the group consisting of polyarylene sulfide resins, polyether ether ketone resins, polyphenylene ether resins, polyoxymethylene resins, polyester resins, polycarbonate resins, polystyrene resins, polyolefin resins, and polyamide resins The carbon fiber reinforced thermoplastic resin composition according to claim 12, wherein The sizing agent is composed of 1 to 80% by mass of sizing agent-coated carbon fibers formed by adhering to 0.1 to 10.0 parts by mass with respect to 100 parts by mass of carbon fibers, and 20 to 99% by mass of thermoplastic resin. Item 14. The carbon fiber reinforced thermoplastic resin composition according to Item 12 or 13 . It is a manufacturing method of the carbon fiber reinforced thermoplastic resin composition of Claim 12 or 13, Comprising: The sizing agent adheres 0.1 to 10.0 mass parts of said sizing agents with respect to 100 mass parts of carbon fibers. A method for producing a carbon fiber-reinforced thermoplastic resin composition, comprising obtaining coated carbon fibers and then melt-kneading 1 to 80% by mass of the sizing agent-coated carbon fibers and 20 to 99% by mass of a thermoplastic resin. The carbon fiber reinforced composite material formed by shape | molding the prepreg of Claim 10 or 11 , or the carbon fiber reinforced thermoplastic resin composition in any one of Claims 12-14 .