JP2012211310A - Carbon fiber-reinforced composite material, prepreg, and method of manufacturing carbon fiber-reinforced composite material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a prepreg that can form an carbon fiber-reinforced composite material excellent in interlayer toughness and the conductivity of a Z-axis direction.SOLUTION: The carbon fiber-reinforced composite material includes: a resin layer including: a resin particle containing a matrix resin and a polyamide resin having a structure shown by formula (1); and a conductive particle whose average particle diameter is larger than that of the resin particle; and carbon fiber layers provided on both principal planes of the resin layer and containing a carbon fiber, wherein the difference between the average thickness of the resin layer and the average particle diameter of the resin particle including the polyamide resin having the structure shown by the following formula (1) is at most 12 μm. In the formula, a and b denote an integer of 0-4, Rand Reach independently denote an alkyl group or a halogen atom, and Rdenotes an alkanediyl group, a cycloalkanediyl group or an alkenediyl group.

Description

  The present invention relates to a carbon fiber reinforced composite material, a prepreg, and a method for producing a carbon fiber reinforced composite material.

  A carbon fiber reinforced composite material (hereinafter, referred to as “CFRP” in some cases) containing carbon fiber and a matrix resin is excellent in strength, rigidity, conductivity, and the like. Widely deployed in applications such as IC trays and notebook PC housings. Among them, there are an increasing number of cases used for structural members such as aircraft members, windmill blades, and automobile outer plates for weight reduction.

  By the way, in addition to the impact resistance and interlaminar toughness that have been demanded so far for structural members, in recent years, carbon fiber reinforced composite materials have been required to have improved conductivity as a measure against large currents such as lightning strikes. . In particular, in a carbon fiber reinforced composite material having an interlayer structure, which has a plurality of carbon fiber layers and a resin layer existing between the carbon fiber layers, the impact resistance and interlayer toughness are obtained. Since this becomes an insulating layer, further improvement in conductivity between carbon fiber layers (that is, conductivity in the thickness direction of the carbon fiber reinforced composite material (hereinafter sometimes referred to as “conductivity in the Z-axis direction”)). It has been demanded.

  As such a carbon fiber reinforced composite material, Patent Document 1 discloses a composite material having an interleaf structure, which is a two-ply conductive fiber reinforcing material and a polymer having a specific thickness disposed between the two plies. A composite material including a resin layer and a specific amount of conductive particles dispersed in a polymer resin is disclosed. However, there are cases where sufficient toughness is not expressed only by the polymer resin layer.

  In Patent Document 2, a carbon fiber reinforced composite material containing particles or fibers of thermoplastic resin and conductive resins or fibers at a specific blending ratio achieves both high impact resistance and conductivity. However, in order to further reduce the weight, a high level of interlayer toughness is required in addition to these.

Special table 2010-508416 JP 2008-231395 A

  Therefore, the present invention provides a carbon fiber reinforced composite material excellent in interlayer toughness and conductivity in the Z-axis direction, a method for producing the carbon fiber reinforced composite material, and a prepreg capable of forming the carbon fiber reinforced composite material. The purpose is to do.

  The present invention includes both a resin layer containing a matrix resin, resin particles containing a polyamide resin having a structure represented by the following formula (1), conductive particles having an average particle size larger than the resin particles, and the resin layer. A carbon fiber layer containing carbon fibers provided on each main surface, and an average particle size of resin particles comprising a polyamide resin having a structure represented by the average thickness of the resin layer and the following formula (1): A carbon fiber reinforced composite material having a difference from the diameter of 12 μm or less, preferably 10 μm or less is provided.

[Wherein, a and b each represent an integer of 0 to 4, R ¹ and R ² each independently represent an alkyl group or a halogen atom, and R ³ represents an alkanediyl group, a cycloalkanediyl group or an alkenediyl group] .

  In the carbon fiber reinforced composite material of the present invention, the polyamide resin having an average particle diameter of the conductive particles larger than the average particle diameter of the resin particles, the average thickness of the resin layer, and the structure represented by the above formula (1) Since the difference from the average particle diameter of the resin particles containing 12 is 12 μm or less, preferably 10 μm or less, the conductive path reliably forms the conductive path between the carbon fiber layers. Therefore, the carbon fiber reinforced composite material of the present invention has excellent conductivity in the Z-axis direction.

  In the carbon fiber reinforced composite material of the present invention, since the resin particles contain the specific polyamide resin, the resin particles are excellent in heat resistance and impact resistance. And the thickness of the resin layer which exists between two carbon fiber layers is hold | maintained by the said resin particle. Therefore, according to the carbon fiber reinforced composite material of the present invention, a change in the thickness of the resin layer due to molding conditions can be sufficiently suppressed.

In the conventional carbon fiber reinforced composite material, the thickness of the resin layer varies due to deformation of the resin particles, so that the interlaminar toughness represented by impact resistance and G _IIC (in-plane shear mode toughness) decreases, The formation of a conductive path by the conductive particles may be hindered and the conductivity may be lowered. On the other hand, the carbon fiber reinforced composite material of the present invention sufficiently suppresses a change in the thickness of the resin layer, thereby realizing excellent interlayer toughness and conductivity.

  In the carbon fiber reinforced composite material of the present invention, at least one of a and b is preferably 0. When at least one of a and b is 0, the heat resistance and impact resistance of the resin particles are further improved.

  In the carbon fiber reinforced composite material of the present invention, the content of the resin particles in the resin layer is preferably 20 to 70% by volume based on the total volume of the resin layer. According to such a carbon fiber composite material, since the change in the thickness of the resin layer is further suppressed, further excellent interlayer toughness and conductivity are realized. In addition, when other resin particles, such as the particle | grains comprised from the nylon 12 mentioned below are further included, it is preferable that the sum total of those contents is 20-70 volume% on the basis of the whole volume of the said resin layer.

  In the carbon fiber reinforced composite material of the present invention, the conductive particles preferably include at least one selected from the group consisting of carbon particles, graphite particles, metal-coated glass particles, and metal-coated organic particles. Such a carbon fiber reinforced composite material is further excellent in interlayer toughness and conductivity.

  In the carbon fiber reinforced composite material of the present invention, the resin particles and the conductive particles preferably have an average particle size of 5 to 100 μm. In such a carbon fiber composite material, since the thickness of the resin layer is stabilized, more excellent interlayer toughness and conductivity are exhibited. In addition, when other resin particles, such as the particle | grains comprised from the nylon 12 mentioned below are further included, it is preferable that those all average particle diameters are 5-100 micrometers.

  The present invention also includes a carbon fiber layer containing carbon fibers, and a thermosetting resin layer provided on at least one surface of the carbon fiber layer, and the thermosetting resin layer is a thermosetting resin. The composition includes resin particles including a polyamide resin having a structure represented by the following formula (1), and conductive particles having an average particle size larger than the resin particles, and the average thickness of the thermosetting resin layer is the above Provided is a prepreg that is not more than 3 times the average particle diameter of resin particles.

[Wherein, a and b each represent an integer of 0 to 4, R ¹ and R ² each independently represent an alkyl group or a halogen atom, and R ³ represents an alkanediyl group, a cycloalkanediyl group or an alkenediyl group] .

  According to the prepreg of the present invention, the carbon fiber reinforced composite material of the present invention can be easily produced.

In the prepreg of the present invention, the ratio T ₂ / T ₁ of the average thickness T ₁ of the carbon fiber layer and the average thickness T ₂ of the thermosetting resin layer is preferably 0.1-1. According to such a prepreg, the carbon fiber reinforced composite material of the present invention can be more easily produced.

  In the prepreg of the present invention, the resin particles and the conductive particles preferably have an average particle size of 5 to 100 μm. In addition, when other resin particles, such as the particle | grains comprised from the nylon 12 mentioned below are further included, it is preferable that those all average particle diameters are 5-100 micrometers.

  Further, in the prepreg of the present invention, the difference between the cumulative 10% particle size and the cumulative 90% particle size of the resin particles containing the polyamide resin having the structure represented by the above formula (1) and the average particle size of the resin particles Is preferably 10 μm or less. By using resin particles having such a particle size distribution, the effects of the present invention are more remarkably exhibited.

  The present invention further provides a laminate in which a plurality of the prepregs of the present invention are laminated to obtain a prepreg laminate having at least one structure in which the carbon fiber layers are respectively disposed on both main surfaces of the thermosetting resin layer. Forming a prepreg laminate and obtaining a carbon fiber reinforced composite material comprising a resin layer formed by curing the thermosetting resin layer, wherein in the molding step, Carbon that forms the prepreg laminate so that the difference between the average thickness and the average particle size of the resin particles containing the polyamide resin having the structure represented by the above formula (1) is 12 μm or less, preferably 10 μm or less. A method for producing a fiber reinforced composite material is provided.

  According to such a production method, a carbon fiber reinforced composite material having excellent interlayer toughness and conductivity in the Z-axis direction can be easily obtained.

  According to the present invention, a carbon fiber reinforced composite material excellent in interlayer toughness and conductivity in the Z-axis direction, a method for producing the carbon fiber reinforced composite material, and a prepreg capable of forming the carbon fiber reinforced composite material are provided. Provided.

It is sectional drawing which shows one Embodiment of the carbon fiber reinforced composite material which concerns on this invention. It is sectional drawing which shows another one Embodiment of the carbon fiber reinforced composite material which concerns on this invention.

  Preferred embodiments of the carbon fiber reinforced composite material and prepreg of the present invention will be described below.

(Prepreg)
The prepreg according to the present embodiment includes a carbon fiber layer containing carbon fibers and a thermosetting resin layer provided on at least one surface of the carbon fiber layer. Here, the thermosetting resin layer includes a thermosetting resin composition, resin particles containing a polyamide resin having a structure represented by the following formula (1), conductive particles having an average particle size larger than the resin particles, The average thickness of the thermosetting resin layer is 3 times or less the average particle diameter of the resin particles.

In the formula, a and b each represent an integer of 0 to 4, R ¹ and R ² each independently represent an alkyl group or a halogen atom, and R ³ represents an alkanediyl group, a cycloalkanediyl group or an alkenediyl group.

  According to the prepreg according to the present embodiment, a carbon fiber reinforced composite material described later can be easily produced.

(Thermosetting resin layer)
The thermosetting resin layer contains (A) a thermosetting resin composition, (B) resin particles, and (C) conductive particles. The thermosetting resin layer is cured by heating when producing a carbon fiber reinforced composite material from a prepreg, and forms a resin layer in the carbon fiber reinforced composite material.

  The average thickness of the thermosetting resin layer is 3 times or less of the average particle diameter of the resin particles, preferably 1 to 3 times, more preferably 1 to 2.5 times. By setting the average thickness of the thermosetting resin layer within the above range, the difference between the average thickness of the resin layer and the average particle diameter of the resin particles including the polyamide resin having the structure represented by the formula (1) is 12 μm. Hereinafter, a carbon fiber reinforced composite material preferably having a thickness of 10 μm or less can be produced more easily.

  In addition, in this specification, the average thickness of a thermosetting resin layer is calculated | required by the method of observing the cross section of the carbon fiber reinforced composite material after thermoforming as mentioned later.

(A) Thermosetting resin composition The thermosetting resin composition contains at least a thermosetting resin and is cured by heat to form a matrix resin in the carbon fiber reinforced composite material.

  As the thermosetting resin, a resin capable of at least partially forming a three-dimensional crosslinked structure by proceeding with a crosslinking reaction by heat is preferable. The thermosetting resin may be self-curing (self-crosslinking) by heat, or may be cured (cross-linking) with a curing agent or the like. When using the latter resin, it is preferable that the thermosetting resin composition further contains a curing agent.

  Examples of the thermosetting resin include unsaturated polyester resin, vinyl ester resin, epoxy resin, benzoxazine resin, phenol resin, urea resin, melamine resin, and polyimide resin. Moreover, as a thermosetting resin, the modified body of these resin, resin which blended two or more types of these resin, etc. can also be used.

  As the thermosetting resin, an epoxy resin is preferably used because of its excellent balance of heat resistance, mechanical properties, and adhesiveness with carbon fibers. As an epoxy resin, the epoxy resin which has 2 or more of epoxy groups in a molecule | numerator is mentioned. In addition, as the epoxy resin, bisphenol type epoxy resin such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, etc .; novolac type epoxy resin; naphthalene type epoxy resin; epoxy resin having fluorene skeleton; Resin based on a copolymer of ethylene and dicyclopentadiene; diglycidyl resorcinol; glycidyl ether type epoxy resin such as tetrakis (glycidyloxyphenyl) ethane, tris (glycidyloxyphenyl) methane; tetraglycidyldiaminodiphenylmethane, triglycidyl Glycidylamine type epoxy resins such as aminophenol, triglycidylaminocresol, tetraglycidylxylenediamine; Carboxymethyl resin; isocyanate-modified epoxy resin; and the like can be used.

  The thermosetting resin may be a single resin or a mixture of these resins. In particular, when a carbon fiber reinforced composite material having a good balance between heat resistance and mechanical properties is required, it is preferable to use a combination of a polyfunctional epoxy resin (a trifunctional or higher functional epoxy resin) and a bifunctional epoxy resin. For example, combining glycidylamine type epoxy resins such as tetraglycidyldiaminodiphenylmethane and triglycidylaminophenol as polyfunctional epoxy resins, and bisphenol type epoxy resins such as bisphenol A type epoxy resins and bisphenol F type epoxy resins as bifunctional epoxy resins Can be used.

  The thermosetting resin composition may contain a curing agent. The kind of hardening | curing agent can be suitably selected according to a thermosetting resin. For example, when an epoxy resin is used as the thermosetting resin, for example, an amine-based curing agent can be used as the curing agent.

  The amine curing agent refers to a curing agent having a nitrogen atom in the curing agent molecule. Examples of the curing agent include 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylsulfone, 3,3′-diaminodiphenylsulfone, m-phenylenediamine, m-xylylenediamine, and diethyltoluenediamine. An aromatic polyamine compound having active hydrogen; an aliphatic amine having active hydrogen such as diethylenetriamine, triethylenetetramine, isophoronediamine, bis (aminomethyl) norbornane, bis (4-aminocyclohexyl) methane, dimer acid ester of polyethyleneimine; Modified amines obtained by reacting these active hydrogen-containing amines with compounds such as epoxy compounds, acrylonitrile, phenol and formaldehyde, thiourea; dimethylaniline, dimethylbenzylamine, 2, 4 Tertiary amines without active hydrogen such as 6-tris (dimethylaminomethyl) phenol, monosubstituted imidazole; dicyandiamide; tetramethylguanidine; polycarboxylic acid hydrazides such as adipic hydrazide and naphthalenedicarboxylic hydrazide; boron trifluoride ethylamine Lewis acid complexes such as complexes; and the like can be used.

  Of the above, dicyandiamide and aromatic polyamine compounds are preferably used as the amine curing agent. When dicyandiamide or an aromatic polyamine compound is used, a matrix resin having further excellent elastic modulus and heat resistance can be obtained. Among them, dicyandiamide, 3,3′-diaminodiphenylsulfone, and 4,4′-diaminodiphenylsulfone can provide a matrix resin having excellent heat resistance, particularly moisture and heat resistance, and can be mixed into an epoxy resin to form a single solution. It is particularly preferable for reasons such as having excellent storage stability.

  In the thermosetting resin composition, an appropriate curing accelerator for enhancing the curing activity can be combined with the curing agent. For example, to dicyandiamide, 3-phenyl-1,1-dimethylurea, 3- (3,4-dichlorophenyl) -1,1-dimethylurea (DCMU), 3- (3-chloro-4-methylphenyl) -1 , 1-dimethylurea, urea derivatives such as 2,4-bis (3,3-dimethylureido) toluene and imidazole derivatives can be suitably used in combination as a curing accelerator. In particular, a combination of dicyandiamide and a compound having two or more urea bonds in one molecule is preferable. Examples of compounds having two or more urea bonds in one molecule include 1,1′-4 (methyl-m-phenylene) bis (3,3-dimethylurea) and 4,4′-methylenebis (phenyldimethylurea). Can be mentioned. When these are used, since the curing time of the matrix resin is shortened, it is preferable for applications that require high productivity.

  In addition to this, there is an example in which a boron trifluoride ethylamine complex is combined with an aromatic amine as a curing accelerator.

  Although content of the hardening | curing agent in a thermosetting resin composition can be suitably changed with the kind of hardening | curing agent, in the case of the amine-type hardening | curing agent which has active hydrogen, for example, the total amount of thermosetting resin is 100 mass parts, The amount is preferably 100 parts by mass, and more preferably 1 to 70 parts by mass. Moreover, preferable heat resistance is obtained by adjusting a compounding quantity so that an active hydrogen equivalent may be 0.6-1.2 equivalent with respect to an epoxy group.

  The thermosetting resin composition may contain a compound other than those described above. For example, a thermoplastic resin can be added to control viscoelasticity or impart toughness. Moreover, in order to improve a flame retardance, a halogen compound, a phosphorus compound, a nitrogen compound, a metal oxide, a metal hydroxide, etc. can also be mix | blended.

  Examples of the thermoplastic resin include polyamide, polycarbonate, polyacetal, polyphenylene oxide, polyphenylene sulfide, polyarylate, polyester, polyamideimide, polyimide, polyetherimide, polyimide having a phenyltrimethylindan structure, polysulfone, polyethersulfone, poly Examples include ether ketone, polyether ether ketone, polyaramid, polyether nitrile, and polybenzimidazole. The thermoplastic resin may have crystallinity or may be amorphous.

  The content of the thermoplastic resin in the thermosetting resin composition is preferably 5 to 50 parts by mass, and more preferably 10 to 40 parts by mass, with the total amount of the thermosetting resin being 100 parts by mass.

(B) Resin Particles The resin particles include a polyamide resin having a structure represented by the formula (1).

In the formula, a and b each represent an integer of 0 to 4, R ¹ and R ² each independently represent an alkyl group or a halogen atom, and R ³ represents an alkanediyl group, a cycloalkanediyl group or an alkenediyl group.

  Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group. It may be.

  Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

  Alkanediyl groups include methylene, ethylene, propylene, butylene, pentanediyl, hexanediyl, heptanediyl, octanediyl, nonanediyl, decandiyl, undecandiyl, dodecandiyl, tridecandiyl, etc. Is mentioned.

  Examples of the cycloalkanediyl group include a cyclopropanediyl group, a cyclobutanediyl group, a cyclopentanediyl group, a cyclohexanediyl group, and a cycloheptanediyl group. Among these, a cyclopentanediyl group, a cyclohexanediyl group, a cycloheptanediyl group, etc. are mentioned.

  Examples of the alkenediyl group include ethenediyl group, propenediyl group, butenediyl group, pentenediyl group, hexenediyl group, heptenediyl group, and octenediyl group.

  In the formula, at least one of a and b is preferably 0.

Moreover, as R < ¹ > and R < ² >, a methyl group, an ethyl group, a propyl group, a chlorine atom, a bromine atom, and a fluorine atom are preferable.

R ³ is preferably an octanediyl group, a nonanediyl group, a decanediyl group, an undecanediyl group, a dodecanediyl group, or a tridecanediyl group.

  Such a polyamide resin is preferably a polyamide resin having 4,4'-diaminodicyclohexylmethane or a derivative thereof and dicarboxylic acid as monomer units.

  Specific examples of 4,4′-diaminodicyclohexylmethane (or derivatives thereof) include 4,4′-diaminodicyclohexylmethane, 4,4′-diamino-3,3′-dimethyldicyclohexylmethane, and 4,4′-diamino. 3,3′-diethyldicyclohexylmethane, 4,4′-diamino-3,3′-dipropyldicyclohexylmethane, 4,4′-diamino-3,3′-dichlorodicyclohexylmethane, 4,4′-diamino- 3,3′-dibromodicyclohexylmethane and the like. Of these, 4,4'-diaminodicyclohexylmethane and 4,4'-diamino-3,3'-dimethyldicyclohexylmethane are preferred from the viewpoint of heat resistance.

  Examples of the dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, lepargic acid, sebacic acid, sebacic acid, 1,12-dodecanedicarboxylic acid and the like. A chain saturated dicarboxylic acid; a chain unsaturated dicarboxylic acid such as maleic acid and fumaric acid; and an alicyclic dicarboxylic acid such as cyclopropanedicarboxylic acid. Of these, 1,12-dodecanedicarboxylic acid is particularly preferable because of its long alkyl chain and high toughness of the resin particles.

  Examples of such a commercially available polyamide resin include “Grillamide (registered trademark)” TR90 (manufactured by Mzavelke) and “TROGAMID (registered trademark)” CX7323 (manufactured by Degussa).

  The resin particles may further contain components other than the polyamide resin, and may further contain, for example, a thermosetting resin.

  The resin particles preferably further include particles composed of nylon 12 having an average particle size smaller than the average particle size of the resin particles including the polyamide resin having the structure represented by the formula (1).

  Since nylon 12 has high toughness, the interlayer toughness of the carbon fiber reinforced composite material is improved by including particles composed of nylon 12 between the layers of the carbon fiber reinforced composite material.

  Moreover, since the particle | grains comprised from this nylon 12 are an average particle diameter smaller than the average particle diameter of the resin particle containing the polyamide resin which has a structure represented by (1), it is the interlayer of a carbon fiber reinforced composite material. Since the thickness is not greatly affected, the interlayer thickness can be controlled by combining with resin particles containing a polyamide resin having a structure represented by the formula (1).

  As a commercial item of nylon 12, "Amilan" (trademark) SP-500, SP-10 (made by Toray Industries, Inc.) etc. are mentioned, for example.

  The mixing ratio of the weight of the particles composed of the polyamide resin having the structure represented by the formula (1) and the particles composed of nylon 12 is preferably 5:95 to 95: 5, and 10:90 to 10:90 is more preferable, and 30:70 to 70:30 is even more preferable.

  Examples of the thermosetting resin include epoxy resin, benzoxazine resin, vinyl ester resin, unsaturated polyester resin, urethane resin, phenol resin, melamine resin, maleimide resin, cyanate ester resin, and urea resin.

  Moreover, the resin particle may further contain a curing agent together with these thermosetting resins. The kind of the curing agent can be appropriately selected according to the thermosetting resin. For example, when the resin particles contain an epoxy resin as the thermosetting resin, the above-described amine-based curing agent may be contained as the curing agent. preferable.

  It is preferable that the compounding quantity of a thermosetting resin is 0.1-25 mass parts with respect to 100 mass parts of polyamide resins, and it is preferable that it is 0.1-12 mass parts. In such resin particles, the toughness of the polyamide resin is sufficiently exhibited and the adhesiveness with the thermosetting resin is further improved.

  The average particle diameter of the resin particles is preferably 5 to 100 μm, and more preferably 7 to 50 μm. In addition, when other resin particles, such as the particle | grains comprised from the said nylon 12, are included further, it is preferable that those all average particle diameters are 5-100 micrometers, and it is more preferable that it is 7-50 micrometers.

  The resin particle content in the thermosetting resin layer is preferably 1 to 90% by volume, more preferably 5 to 70% by volume, based on the total volume of the thermosetting resin layer.

  Further, the difference between the cumulative 10% particle size and the cumulative 90% particle size of the resin particles containing the polyamide resin having the structure represented by the formula (1) and the average particle size of the resin particles is 10 μm or less. preferable. By using resin particles having such a particle size distribution, the effects of the present invention are more remarkably exhibited.

  Here, the average particle diameter, the cumulative 10% particle diameter, and the cumulative 90% particle diameter of the resin particles can be obtained by a laser diffraction method after dispersing the resin particles in a dispersion medium. Specifically, the average particle diameter, the cumulative 10% particle diameter, and the cumulative 90% particle diameter can be obtained by performing a laser diffraction method with the following measurement apparatus, dispersion medium, and measurement conditions.

Measuring device: LA-950V2 (manufactured by Horiba)
Dispersion medium: “Triton X (registered trademark)” 100 0.5 mass% aqueous solution Measurement cell: flow cell Ultrasonic irradiation time: 10 seconds Dispersion liquid: Dispersion liquid in which 1 g of resin particles was added to 100 ml of the dispersion medium and stirred.

The resin particles can be produced, for example, by the following method.
(1) The polyamide resin is melted by heating and crystallized by cooling. At this time, the thermosetting resin can also be mixed with the polyamide resin and added.
(2) The polyamide resin is dissolved in a solvent, and the solvent is volatilized and removed for crystallization. At this time, the thermosetting resin can also be dissolved in the same solvent as the polyamide resin and added.
(3) Polyamide resin is dissolved in a solvent, sprayed in a mist and dried (spray drying method). At this time, the thermosetting resin can also be dissolved in the same solvent as the polyamide resin and added.
(4) A polyamide resin is dissolved in a solvent, and is poured into a solvent that does not dissolve the polyamide resin in a mist state and precipitated (spray reprecipitation method). At this time, the thermosetting resin can also be dissolved in the same solvent as the polyamide resin and added.
(5) A polyamide solution obtained by dissolving a polyamide resin in a solvent is added and mixed in a poor solvent of the polyamide resin and incompatible with the solvent of the polyamide resin, and stirred vigorously to obtain an emulsified and dispersed state. After that, the solvent in the dispersion is removed, and the polyamide resin is taken out. At this time, the thermosetting resin can also be dissolved in the same solvent as the polyamide resin and added.
(6) The polyamide resin is dissolved in a solvent, and the solution is emulsified by gradually adding a dispersion medium that is insoluble or hardly soluble in the solution while stirring the solution. Then, after removing a solvent, it collects as a resin particle. At this time, the thermosetting resin can also be dissolved in the same solvent as the polyamide resin and added.
(7) Grind using a mechanical grinder using a ball mill, jet mill or the like.
(8) The polymerization monomer is polymerized into particles using a polymerization method such as emulsion polymerization, non-aqueous dispersion polymerization, seed emulsion polymerization, and suspension polymerization.

  Among these methods, as a method that can be classified as a chemical pulverization method and that can easily obtain resin particles, (6) can be mentioned. Examples of the solvent used in the method (6) include hydrocarbons such as pentane, hexane, heptane, benzene, toluene, cyclohexane, petroleum ether; methylene chloride, chloroform, dichloroethane, dichloroethylene, 1,1,1-trichloroethylene. Halogenated hydrocarbons such as trichloroethylene and carbon tetrachloride; ethers such as diethyl ether; esters such as ethyl acetate; ketones such as methyl ethyl ketone; and these may be used as a mixture of two or more. Good.

  A small amount of a solvent such as methanol or ethanol can be used for the purpose of further improving the solubility of the polyamide resin in the solvent. The solvent to be used is appropriately selected depending on the type of polyamide resin, and the amount thereof is preferably an amount such that the viscosity of the polyamide solution at the start of emulsification is 0.1 to 800 millipascal seconds, and 10 to 500 millipascals. It is more preferable that the amount is seconds, and even more preferable that the amount is 50 to 300 millipascal seconds.

  Examples of the dispersion medium that is insoluble or hardly soluble in the solution used in the method (6) include water, and it is preferable to select a dispersion medium having a solubility parameter different from that of the solvent. For example, chloroform as a solvent, water as a dispersion medium, a mixture of chloroform and methanol as a solvent, water as a dispersion medium, chloroform as a solvent, and a mixture of water and methanol as a dispersion medium.

  When the viscosity of the polyamide solution before phase inversion is less than 0.1 millipascal second, the amount of the solvent in the polyamide solution is relatively large, and as a result, the solvent distillation time is likely to be long. Further, coalescence between the particles may occur during the emulsification operation or during the solvent volatilization operation, and non-spherical particles may be generated or may be in the form of a bowl, so that an emulsified liquid may not be obtained. On the other hand, when the viscosity of the polyamide solution at the time of emulsification exceeds 800 millipascal seconds, the polyamide solution becomes very viscous, and a large load is applied to the stirring device, and smooth emulsification may not be performed.

  The temperature during emulsification is not particularly problematic as long as it is not higher than the boiling point of the dispersion medium, but is preferably not higher than the boiling point of the solvent. The pressure during emulsification may be normal pressure or increased pressure. Normal pressure is more preferred. Such a pressure reaction system has the advantage that the members for constructing it are inexpensive.

  Examples of the emulsifier used in the method (6) include polyvinyl alcohol, carboxymethylcellulose, hydroxymethylcellulose, hydroxypropylcellulose, hydroxyethylcellulose, modified starch, polyvinylpyrrolidone, gelatin, gum arabic, and casein. You may use together nonionic, anionic, and cationic surfactant with said emulsifier as needed. These emulsifiers can be added to a polyamide solution or a dispersion medium that is hardly compatible with the solution. Moreover, you may add to both solutions.

  Such an emulsifier is preferably blended in an amount of 0.01 to 20% by weight, more preferably 0.1 to 15% by weight, in the emulsion before phase inversion. This further increases the stability of the emulsion. A solvent-containing polyamide solution having a particle diameter of 0.1 to 150 μm is obtained by gradually adding a dispersion medium that is insoluble or hardly soluble in the stirred polyamide solution gradually or by phase inversion emulsification. It is done. The stirring speed at that time is preferably 10 to 1500 rpm, and more preferably 50 to 1000 rpm from the viewpoint that the particle size becomes uniform.

  The organic solvent of the obtained emulsion is heated at a temperature at which the used organic solvent volatilizes, and is volatilized and removed while reducing the pressure as necessary. A preferable temperature at this time is less than 100 ° C. The slurry from which the organic solvent has been removed is subjected to solid-liquid separation by filtration or centrifugal separation, and the resulting liquid-containing solid content is washed and dried to obtain resin particles.

  According to such a method, it is possible to easily obtain resin particles having an average particle diameter in the above-mentioned preferable range.

  In the above methods (2) to (6), the polyamide solution is further added with an inorganic substance such as silica, alumina, mica, thermoplastic resin, rubber, pigment, dye, antioxidant, lubricant, antistatic agent, plasticizer. Etc. may be dispersed and dissolved. Further, it is possible to improve the dispersibility and fluidity by adsorbing or spraying ultrafine particles such as silica and alumina on the surface of the resin fine particles in the emulsion or dry state.

(C) Conductive Particles The conductive particles contained in the thermosetting resin layer are particles having an average particle size larger than that of the resin particles, and may be particles that behave as an electrically good conductor. It is not limited. The conductive particles are preferably particles having a volume resistivity of 10 to 10 ⁻⁹ Ωcm, more preferably 1 to 10 ⁻⁹ Ωcm.

  The average particle size of the conductive particles is preferably 5 to 100 μm, and more preferably 7 to 50 μm. Here, the average particle diameter of the conductive particles can be determined by a laser diffraction method in the same manner as the measurement of the average particle diameter of the resin particles described above.

  The content of the conductive particles in the thermosetting resin layer is preferably 0.1 to 35% by volume and preferably 0.2 to 20% by volume based on the total volume of the thermosetting resin layer. More preferred.

  Conductive particles include metal particles; conductive polymer particles such as polyacetylene particles, polyaniline particles, polypyrrole particles, polythiophene particles, polyisothianaphthene particles, and polyethylenedioxythiophene particles; carbon particles; graphite particles; coated with a conductive material Inorganic particles; organic particles coated with a conductive substance; and the like can be used.

  As an inorganic particle, the particle | grains which consist of an inorganic oxide, an inorganic organic composite, carbon etc. are mentioned, for example.

  Examples of the inorganic oxide include inorganic oxides such as silica, alumina, zirconia, and titania; composite inorganic oxides such as silica / alumina and silica / zirconia.

  Moreover, as an inorganic organic composite, the polyorganosiloxane obtained by hydrolyzing a metal alkoxide and / or a metal alkyl alkoxide is mentioned, for example.

  As carbon, crystalline carbon and amorphous carbon are preferably used. As the amorphous carbon, for example, “Bellpearl” (registered trademark) C-600, C-800, C-2000 (manufactured by Air Water Co., Ltd.), “NICABEADS” (registered trademark) ICB, PC, MC ( Nippon Carbon Co., Ltd.).

  Examples of the organic particles include unsaturated polyester resins, vinyl ester resins, epoxy resins, benzoxazine resins, phenol resins, urea resins, melamine resins and polyimide resins, thermosetting resins, polyamide resins, phenol resins, amino resins, Examples thereof include particles made of a thermoplastic resin such as acrylic resin, ethylene-vinyl acetate resin, polyester resin, urea resin, melamine resin, alkyd resin, polyimide resin, urethane resin, divinylbenzene resin. The particles may contain two or more of these thermoplastic resins. Of these thermoplastic resins, acrylic resins and divinylbenzene resins having excellent heat resistance, and polyamide resins having excellent impact resistance are preferably used.

  The conductive substance that coats the inorganic particles or the organic particles may be any substance that behaves as an electrically good conductor. Examples of the conductive substance include carbon, metal, and the like. When carbon is used as the conductive material, carbon black such as channel black, thermal black, furnace black, ketjen black, hollow carbon fiber, and the like are preferably used.

  When a metal is used as the conductive material, any metal may be used, but a metal having a standard electrode potential of −2.0 to 2.0 V, more preferably a metal having −1.8 to 1.8 V is preferable. . If the standard electrode potential is too low, it may be unstable and unfavorable for safety, and if it is too high, workability and productivity may be reduced. Here, the standard electrode potential refers to the electrode potential when a metal is immersed in a solution containing the metal ions and the standard hydrogen electrode (platinum immersed in a 1N HCl solution in contact with hydrogen gas at 1 atm. Electrode) expressed as a difference from the potential. For example, Ti: -1.74V, Ni: -0.26V, Cu: 0.34V, Ag: 0.80V, Au: 1.52V.

  The conductive particles preferably include at least one selected from the group consisting of carbon particles, graphite particles, metal-coated glass particles, and metal-coated organic particles. According to such conductive particles, the effects of the present invention are more remarkably exhibited.

(Carbon fiber layer)
The carbon fiber layer contains (D) carbon fiber. The carbon fiber layer may contain, for example, carbon fibers and a thermosetting resin composition impregnated in the carbon fibers.

The ratio T ₂ / T ₁ of the average thickness T ₁ of the carbon fiber layer and the average thickness T ₂ of the thermosetting resin layer is preferably 0.1-1. According to such a prepreg, the carbon fiber reinforced composite material according to the present embodiment can be more easily produced.

  In the present specification, the average thickness of the carbon fiber layer of the prepreg is obtained by curing the prepreg, observing a cross section, measuring the thickness of 20 points or more, and averaging.

(D) Carbon fiber Examples of the carbon fiber include PAN-based carbon fiber obtained by carbonizing polyacrylonitrile (PAN) fiber, pitch-based carbon fiber obtained by carbonizing pitch fiber, and the like. As the carbon fiber, PAN-based carbon fiber is preferable because high tensile and compressive strength can be easily obtained.

  The tensile elastic modulus of the carbon fiber is preferably 230 GPa or more, and more preferably 260 GPa or more. According to the prepreg containing such a carbon fiber, a carbon fiber reinforced composite material having further excellent conductivity can be obtained. Moreover, it is preferable that the tensile elasticity modulus of carbon fiber is 440 GPa or less, and it is more preferable that it is 400 GPa or less. According to the prepreg containing such a carbon fiber, a carbon fiber reinforced composite material having further excellent impact resistance can be obtained.

  That is, the tensile elastic modulus of the carbon fiber is preferably 230 to 440 GPa, more preferably 260 to 440 GPa. According to the prepreg containing such a carbon fiber, a carbon fiber reinforced composite material having both higher conductivity and impact resistance can be obtained.

  The tensile strength of the carbon fiber is preferably 4.4 to 6.5 GPa. Moreover, it is preferable that the tensile elongation of carbon fiber is 1.7 to 2.3%. According to the prepreg containing such carbon fibers, a carbon fiber reinforced composite material having further excellent impact resistance and high rigidity and mechanical strength can be obtained.

  The tensile modulus, tensile strength, and tensile elongation can be measured by a strand tensile test described in JIS R7601-1986.

(Manufacture of prepreg)
The prepreg according to the present embodiment is manufactured by applying a known method as disclosed in, for example, Japanese Patent Laid-Open Nos. 1-226651, 63-170427, 63-170428. can do. Specifically, for example, it can be produced by the following method.

  That is, a thermosetting resin composition is formed by applying a pressure by applying a resin film formed by coating a thermosetting resin composition on release paper or the like to both or one side of a carbon fiber aligned in a sheet shape. Carbon fiber is impregnated with the product to produce a primary prepreg (carbon fiber layer). Next, the resin particles and the conductive particles are dispersed in the thermosetting resin composition and coated on a release paper or the like, thereby producing a particle-containing resin film (thermosetting resin layer). And a prepreg can be produced by sticking a particle content resin film on both sides or one side of a primary prepreg.

(Carbon fiber reinforced composite material)
The carbon fiber reinforced composite material according to the present embodiment includes a resin layer and a carbon fiber layer 1 containing carbon fibers provided on both main surfaces 7 of the resin layer 2 as shown in FIG. The resin layer 2 contains a matrix resin 6, resin particles 3 including a polyamide resin having a structure represented by the formula (1), and conductive particles 4 having an average particle size larger than the resin particles. The difference between the average thickness of the layer 2 and the average particle diameter of the resin particles 3 containing the polyamide resin having the structure represented by the formula (1) is 12 μm or less, preferably 10 μm or less.

  In the carbon fiber reinforced composite material according to the present embodiment, the average particle diameter of the conductive particles is larger than the average particle diameter of the resin particles including the polyamide resin having the structure represented by the formula (1), and the average thickness of the resin layer. And the average particle size of the resin particles containing the polyamide resin having the structure represented by the above formula (1) is 12 μm or less, preferably 10 μm or less. Is reliably formed. Therefore, the carbon fiber reinforced composite material according to this embodiment has excellent conductivity in the Z-axis direction.

  Moreover, the carbon fiber reinforced composite material according to another embodiment includes a resin layer and a carbon fiber layer 1 containing carbon fibers provided on both main surfaces 7 of the resin layer 2 as shown in FIG. Is provided. The resin layer 2 includes a matrix resin 6, resin particles 3 including a polyamide resin having a structure represented by the formula (1), conductive particles 4 having an average particle size larger than the resin particles, and a formula (1). Particles 8 composed of nylon 12 having an average particle size smaller than the average particle size of resin particles containing a polyamide resin having a structure represented by formula (1): The difference from the average particle size of the resin particles 3 containing the polyamide resin having the structure is 12 μm or less, preferably 10 μm or less.

  Even in the carbon fiber reinforced composite material according to the present embodiment, the average particle diameter of the conductive particles is larger than the average particle diameter of the resin particles including the polyamide resin having the structure represented by the formula (1), and is represented by the formula (1). The average particle size of the resin particles containing the polyamide resin having the structure is the same as or larger than the average particle size of the particles composed of nylon 12, and the average thickness of the resin layer is expressed by the above formula (1). Since the difference from the average particle diameter of the resin particles containing the polyamide resin having the structure is 12 μm or less, preferably 10 μm or less, the conductive path reliably forms the conductive path between the carbon fiber layers. Therefore, the carbon fiber reinforced composite material according to this embodiment has excellent conductivity in the Z-axis direction.

  Moreover, in the carbon fiber reinforced composite material according to this embodiment, the resin particles are excellent in heat resistance and interlayer toughness because they contain the specific polyamide resin. And the thickness of the resin layer which exists between two carbon fiber layers is hold | maintained by the said resin particle. Therefore, according to the carbon fiber reinforced composite material according to the present embodiment, the thickness of the resin layer being molded can be sufficiently prevented from changing.

In the conventional carbon fiber reinforced composite material, the thickness of the resin layer varies due to deformation of the resin particles during molding, resulting in a decrease in impact resistance and interlayer toughness typified by _GIIC , and a conductive path caused by conductive particles. In some cases, the formation of is hindered and the conductivity is lowered. On the other hand, the carbon fiber reinforced composite material according to the present embodiment sufficiently suppresses a change in the thickness of the resin layer, so that excellent interlayer toughness and conductivity are realized.

(Resin layer)
The resin layer contains a matrix resin, resin particles, and conductive particles. The matrix resin is preferably a cured product of a thermosetting resin composition. Moreover, as a resin particle and electroconductive particle, the thing similar to the above can be illustrated.

  The difference between the average thickness of the resin layer and the average particle diameter of the resin particles containing the polyamide resin having the structure represented by the formula (1) is 12 μm or less, preferably 10 μm or less, and preferably 7 μm or less. More preferred. In addition, in this specification, the average thickness of a resin layer is calculated | required by the below-mentioned method.

  The resin particle content in the resin layer is preferably 20 to 70% by volume, more preferably 20 to 65% by volume, based on the total volume of the resin layer. According to such a carbon fiber composite material, since the change in the thickness of the resin layer is further suppressed, further excellent interlayer toughness and conductivity are realized. In addition, when other resin particles such as particles composed of the nylon 12 are further included, for the same reason, the total content thereof is 20 to 70% by volume based on the total volume of the resin layer. It is preferably 20 to 65% by volume.

  The content of the conductive particles in the resin layer is preferably 0.1 to 35% by volume, and more preferably 0.2 to 20% by volume based on the total volume of the resin layer. According to such a carbon fiber composite material, since a conductive path is more reliably formed, a further excellent conductivity can be obtained.

(Carbon fiber layer)
The carbon fiber layer contains carbon fibers, and preferably further contains a matrix resin that is a cured product of the thermosetting resin composition.

In the carbon fiber reinforced composite material, the ratio T ₃ / T ₄ of the average thickness T ₃ of the carbon fiber layer and the average thickness T ₄ of the resin layer is preferably 1 to 15, and preferably 1 to 10. More preferred. In addition, in this specification, the average thickness of the carbon fiber layer of a carbon fiber reinforced composite material is calculated | required by the below-mentioned method.

(Method for producing carbon fiber reinforced composite material)
In the present embodiment, the carbon fiber reinforced composite material can be manufactured by a manufacturing method including the following lamination process and molding process.

(Lamination process)
In the laminating step, a plurality of the prepregs are laminated to obtain a prepreg laminate having at least one structure in which the carbon fiber layers are respectively disposed on both main surfaces of the thermosetting resin layer. The prepreg laminate preferably has a structure in which carbon fiber layers and thermosetting resin layers are alternately laminated.

(Molding process)
In the molding step, the difference between the average thickness of the resin layer and the average particle diameter of the resin particles containing the polyamide resin having the structure represented by the formula (1) is preferably 12 μm or less by heating and pressing the prepreg laminate. Forms a carbon fiber reinforced composite material having a thickness of 10 μm or less. Here, as a heating / pressurizing method, a method is selected in which the thermosetting resin composition in the thermosetting resin layer is cured to form a matrix resin.

  Examples of the heating / pressurizing method include a press molding method, an autoclave molding method, a bagging molding method, a wrapping tape method, an internal pressure molding method, and the like. Among these, the autoclave molding method is preferably used.

  According to such a production method, a carbon fiber reinforced composite material having excellent interlayer toughness and conductivity in the Z-axis direction can be easily obtained.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited to an Example.

  In order to obtain the prepreg of each Example and Comparative Example, the following raw materials were used.

(A) Thermosetting resin composition “Araldite (registered trademark)” MY721: N, N, N ′, N′-tetraglycidyldiaminodiphenylmethane (manufactured by Huntsman Advanced Materials, hereinafter referred to as “(A1)”). )
“Araldite (registered trademark)” MY0600: N, N, O-triglycidyl-m-aminophenol (manufactured by Huntsman Advanced Materials, hereinafter referred to as “(A2)”)
"Araldite (registered trademark)" GY282: Bisphenol F type epoxy resin (manufactured by Huntsman Advanced Materials, hereinafter represented by "(A3)")
"Sumika Excel (registered trademark)" 5003P: polyethersulfone (manufactured by Sumitomo Chemical Co., Ltd., hereinafter represented by "(A4)")
“Aradur (registered trademark)” 976-1: 4,4′-diaminodiphenyl sulfone (manufactured by Huntsman Advanced Materials, hereinafter referred to as “(A5)”).

(B) Resin particles • Particles having an average particle diameter of 19.5 μm, a cumulative 10% particle diameter of 10.5 μm, and a cumulative 90% particle diameter of 27.5 μm (hereinafter referred to as “(” B1) ”)
-“TROGAMID (registered trademark)” CX7323 as a raw material and having a particle size of 15.2 μm, a cumulative 10% particle size of 7.5 μm, and a cumulative 90% particle size of 19.5 (hereinafter referred to as “(B2)”) .

<Production of (B1)>
In a 1000 ml four-necked flask, 20 g of polyamide as polymer A (weight average molecular weight 17,000, “TROGAMID (registered trademark)” CX7323 manufactured by Degussa Co., Ltd.), 500 g of formic acid as an organic solvent, and 20 g of polyvinyl alcohol as polymer B (PVA 1000 manufactured by Wako Pure Chemical Industries, Ltd.) was added, heated to 80 ° C., and stirred until the polymer was dissolved. After the temperature of the system was lowered to 55 ° C., 500 g of ion-exchanged water as a poor solvent was added dropwise via a liquid feed pump while stirring at 900 rpm. The dropping was started at a speed of 0.5 g / min, the dropping speed was gradually increased, and the whole amount was dropped over 90 minutes. The system turned white when 100 g of ion-exchanged water was added. In addition, the temperature of the system was raised to 60 ° C. when half the amount of ion-exchanged water was dropped, and then the remaining ion-exchanged water was added and the whole amount was dropped, followed by stirring for 30 minutes. The suspension returned to room temperature was filtered, washed with 500 g of ion-exchanged water, and vacuum-dried at 80 ° C. for 10 hours to obtain 11 g of a powdery white solid. When the particle size of the obtained powder was measured by a laser diffraction method, it was polyamide fine particles having an average particle size of 19.5 μm. The cumulative 10% particle size was 10.5 μm and the cumulative 90% particle size was 27.5 μm.

<Production of (B2)>
Except having changed the stirring speed into 1000 rpm, it carried out similarly to Example 1, and obtained powdery white solid 10g. When the particle size of the obtained powder was measured by a laser diffraction method, it was polyamide fine particles having an average particle size of 12.5 μm. The cumulative 10% particle size was 7.5 μm, and the cumulative 90% particle size was 19.5.
“Amilan (registered trademark)” SP-500: Nylon 12 particles (average particle size: 5 μm, manufactured by Toray Industries, Inc., shape: true sphere) (hereinafter referred to as “(B3)”).
“Amilan (registered trademark)” SP-10: Nylon 12 particles (average particle size: 10 μm, manufactured by Toray Industries, Inc., shape: true sphere) (hereinafter referred to as “(B4)”).

(C) Conductive Particles “Micropearl (registered trademark)” AU225: Gold-coated conductive particles (average particle size 25 μm, Sekisui Chemical, hereinafter referred to as “(C1)”)
“Bellepearl (registered trademark)” C-2000: Amorphous carbon particles (average particle size 18 μm, Air Water Co., Ltd., hereinafter referred to as “C2”).

(D) Carbon fiber "Torayca" (registered trademark) T800G-24K-10E (24,000 fibers, tensile strength 5.9 GPa, tensile elastic modulus 290 GPa, tensile elongation 2.0% carbon fiber, total fineness 1.03 g / m, manufactured by Toray Industries, Inc., hereinafter referred to as “(D1)”).

(E) Other Particles • Orgasol (registered trademark) “2002D: Nylon 12 particles (average particle size 20 μm, manufactured by Arkema Co., Ltd., hereinafter referred to as“ (E1) ”).

Example 1
A thermosetting resin composition having the composition shown in Table 1 was applied onto release paper using a knife coater to prepare a 25 g / m ² resin film. Next, on the carbon fibers (D1) arranged in one direction in a sheet shape, two resin films are stacked from both sides of the carbon fibers (D1) and impregnated with the resin by heating and pressurization, and the basis weight of the carbon fibers is 190 g / A m ² unidirectional pre-impregnated prepreg was prepared.

Next, a 39 g / m ² resin film was prepared on a release paper using the thermosetting resin composition having the composition shown in Table 1, and 9.2 g of resin particles (B1) per 1 m ² on the resin film and After uniformly dispersing 1.8 g of conductive particles (C1), a release paper was placed on the particles and heated at 100 ° C. for 1 minute to precipitate the particles in the resin film. This particle-containing resin film was attached to one side of a unidirectional pre-impregnated prepreg and transferred by heating at 100 ° C. for 1 minute to obtain a prepreg.

About the obtained prepreg, the average thickness of a thermosetting resin layer and a carbon fiber layer was measured with the following method. Moreover, the carbon fiber reinforced composite material was produced with the following method, and the G _IIc (ENF) test and the measurement of volume resistivity were performed. Further, the average thickness (interlayer thickness) of the resin layer of the carbon fiber reinforced composite material and the abundance ratio of the conductive particles in the resin layer were measured by the following methods. The results are shown in Table 1.

(Measurement of average thickness of prepreg thermosetting resin layer and carbon fiber layer)
One prepreg is heated from room temperature to 100 ° C at a heating rate of 0.05 ° C / min in an oven, held for 1 hour, heated to 180 ° C at 0.05 ° C / min, and resin is added at 180 ° C for 2 hours. Cured. The cured product of the prepreg was cut in a direction perpendicular to the fiber direction of the carbon fiber, and the cut surface was observed. The distance from the surface of the cured thermosetting resin layer to the surface in contact with the carbon fiber layer was measured at 20 points and averaged to obtain the average thickness of the thermosetting resin layer of the prepreg. Moreover, the thickness of the carbon fiber layer was measured at 20 points and averaged to obtain the average thickness of the carbon fiber layer of the prepreg. From the average thickness obtained, the thickness ratio was determined by the following formula.

  Thickness ratio = (average thickness of thermosetting resin layer) / (average thickness of carbon fiber layer).

(G _IIc (ENF) test)
Thirty prepregs having a size of 200 × 250 mm were cut out and laminated so that the fiber directions were the same. Further, at the time of lamination, a polyimide film (thickness: 0.3 mm) subjected to mold release treatment was inserted into the central surface of the lamination so that the edge was perpendicular to the fiber direction in order to introduce an initial crack. The polyimide film was arrange | positioned so that the front-end | tip may be located in 40 mm from the edge of a laminated body. This laminate was cured by heating and pressing at 180 ° C. and an internal pressure of 0.59 MPa for 2 hours in an autoclave to form a unidirectional carbon fiber reinforced composite material. This unidirectional carbon fiber reinforced composite material was cut into 20 × 195 mm to obtain a test piece. This test piece was subjected to an ENF test in accordance with JIS K7086 (1993) Appendix 2.

(Measurement of volume resistivity)
Pre-pregs were each laminated in a [is -45 ° / 0 ° / + 45 ° / 90 °] _3s configuration in a quasi-isotropic 24 ply manner, and autoclaved at a temperature of 180 ° C. for 2 hours under a pressure of 0.59 MPa. Then, 25 laminates were produced by molding at a heating rate of 1.5 ° C./min. From each of these laminates, a 50 mm long × 50 mm wide (thickness 3 mm) sample was cut out, the resin layers on both surfaces were removed by polishing, and then conductive paste “Dotite” (registered trademark) D-550 (Fujikura) on both sides. The sample which apply | coated Kasei Co., Ltd. was produced. These samples were measured for resistance in the stacking direction by a four-terminal method using an R6581 digital multimeter manufactured by Advantest Corp. to determine volume resistivity.

(Measurement of interlayer thickness and ratio of conductive particles)
The laminate produced by measuring the volume resistivity was cut in the 0 degree direction and the 90 degree direction to obtain two cross sections. Between the two carbon fiber layers including carbon fiber layers arranged in the cutting direction (0 degree layer when cut in the 0 degree direction and 90 degree layer when cut in the 90 degree direction) with respect to this cross section The thickness of the resin layer between the two carbon fiber layers was measured at 20 points per layer, and the average of the two steps was taken as the interlayer thickness (average thickness of the resin layer). The measured interlayer was photographed, and the resin (matrix resin and resin particles) and conductive particles existing between the layers were color-coded, and then the ratio of the area of the resin and conductive particles was calculated. This ratio was defined as the abundance ratio of the conductive particles (in the resin layer) between the layers.

(Examples 2 to 12, Comparative Examples 1 to 3)
A unidirectional pre-impregnated prepreg was prepared in the same manner as in Example 1 except that the thermosetting resin compositions having the compositions shown in Tables 1 to 4 were used, and particles having the compounding ratios shown in Tables 1 to 4 were obtained. A containing resin film was prepared. And the prepreg was obtained like Example 1 using the unidirectional pre-impregnation prepreg and the particle-containing resin film.

About the obtained prepreg, the average thickness of a thermosetting resin layer and a carbon fiber layer was measured by said method. In addition, a carbon fiber reinforced composite material was prepared by the above method, and a G _IIc (ENF) test and volume resistivity were measured. Furthermore, the average thickness (interlayer thickness) of the resin layer of the carbon fiber reinforced composite material and the abundance ratio of the conductive particles in the resin layer were measured by the above method. The results are shown in Tables 1-4.

1: Carbon fiber layer 2: Resin layer 3: Resin particles containing polyamide resin having a structure represented by the formula (1) 4: Conductive particles 5: Carbon fiber 6: Matrix resin 7: Main surface of resin layer 8: Particles composed of nylon 12

Claims (12)

A resin layer containing matrix resin, resin particles containing polyamide resin having a structure represented by the following formula (1), and conductive particles having an average particle size larger than the resin particles;
Carbon fiber layers containing carbon fibers provided on both main surfaces of the resin layer,
With
A carbon fiber reinforced composite material, wherein a difference between an average thickness of the resin layer and an average particle diameter of resin particles containing a polyamide resin having a structure represented by the following formula (1) is 12 μm or less.

[Wherein, a and b each represent an integer of 0 to 4, R ¹ and R ² each independently represent an alkyl group or a halogen atom, and R ³ represents an alkanediyl group, a cycloalkanediyl group or an alkenediyl group. ] The carbon fiber reinforced composite material according to claim 1, wherein at least one of a and b is 0. The said resin particle further contains the particle | grains comprised from the nylon 12 of an average particle diameter smaller than the average particle diameter of the resin particle containing the polyamide resin which has a structure represented by said Formula (1). 2. The carbon fiber reinforced composite material according to 2. The carbon fiber reinforced composite material according to any one of claims 1 to 3, wherein a content of the resin particles in the resin layer is 20 to 70% by volume based on a total volume of the resin layer. The carbon fiber reinforcement according to any one of claims 1 to 4, wherein the conductive particles include at least one selected from the group consisting of carbon particles, graphite particles, metal-coated glass particles, and metal-coated organic particles. Composite material. The carbon fiber reinforced composite material according to any one of claims 1 to 5, wherein an average particle diameter of the resin particles and the conductive particles is 5 to 100 µm. A carbon fiber layer containing carbon fibers;
A thermosetting resin layer provided on at least one surface of the carbon fiber layer;
With
The thermosetting resin layer contains a thermosetting resin composition, resin particles including a polyamide resin having a structure represented by the following formula (1), and conductive particles having an average particle size larger than the resin particles,
The prepreg whose average thickness of the said thermosetting resin layer is 3 times or less of the average particle diameter of the resin particle containing the polyamide resin which has a structure represented by following formula (1).

[Wherein, a and b each represent an integer of 0 to 4, R ¹ and R ² each independently represent an alkyl group or a halogen atom, and R ³ represents an alkanediyl group, a cycloalkanediyl group or an alkenediyl group. ] The said resin particle further contains the particle | grains comprised from the nylon 12 of an average particle diameter smaller than the average particle diameter of the resin particle containing the polyamide resin which has a structure represented by said Formula (1). The prepreg as described. The prepreg according to claim 7 or 8, wherein a ratio T ₂ / T _{1 of} an average thickness T ₁ of the carbon fiber layer and an average thickness T ₂ of the thermosetting resin layer is 0.1-1. The prepreg as described in any one of Claims 7-9 whose average particle diameters of the said resin particle and the said electroconductive particle are 5-100 micrometers. The difference between the cumulative 10% particle size and 90% cumulative particle size of the resin particles containing the polyamide resin having the structure represented by the formula (1) and the average particle size of the resin particles is 10 μm or less. The prepreg according to any one of Items 7 to 10. A prepreg laminate having a structure in which a plurality of the prepregs according to any one of claims 7 to 11 are laminated and the carbon fiber layers are respectively disposed on both main surfaces of the thermosetting resin layer. A laminating process for obtaining a body;
A molding step of forming the prepreg laminate and obtaining a carbon fiber reinforced composite material comprising a resin layer formed by curing the thermosetting resin layer;
With
In the molding step, the prepreg laminate is formed such that the difference between the average thickness of the resin layer and the average particle size of the resin particles containing the polyamide resin having the structure represented by the formula (1) is 12 μm or less. A method for producing a carbon fiber reinforced composite material to be molded.

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