JP6118655B2 - Prepreg, method for producing the same, and fiber-reinforced composite material using the same - Google Patents

Description

The present invention relates to a prepreg suitable as a raw material for producing a fiber-reinforced composite material, a method for producing the same, and a fiber-reinforced composite material produced using the prepreg. More specifically, the present invention relates to a prepreg capable of producing a fiber-reinforced composite material having excellent conductivity.

  Fiber reinforced composite materials composed of reinforced fibers and resins have features such as light weight, high strength, and high elastic modulus, and are widely applied to aircraft, sports / leisure, and general industries. This fiber-reinforced composite material is often manufactured via a prepreg in which reinforcing fibers and a resin called a matrix resin are integrated in advance.

  A fiber reinforced composite material produced by molding a prepreg having reinforced fibers and a matrix resin as essential constituent elements is a heterogeneous material. Usually, in a fiber-reinforced composite material, there is a great difference between the physical properties in the arrangement direction of the reinforcing fibers and the physical properties in other directions.

  For example, impact resistance, which is a measure of resistance to falling weight impact, is governed by delamination strength quantified by interlayer plate end peel strength or the like. Therefore, it is known that merely improving the strength of the reinforcing fiber does not lead to drastic improvement in the physical properties of the fiber-reinforced composite material. In particular, thermosetting resins have low toughness. Therefore, a fiber reinforced composite material using a thermosetting resin as a matrix resin reflects the low toughness of the matrix resin, and is easily broken against stress applied from other than the direction in which the reinforcing fibers are arranged. In order to solve this problem, various techniques have been proposed that make it possible to cope with stress applied from other than the direction in which the reinforcing fibers are arranged.

  As one of them, a prepreg has been proposed in which a resin layer in which resin particles are dispersed is provided in the surface region of the prepreg. Specifically, it is described that a high-toughness composite material with good heat resistance can be produced by using a prepreg in which a resin layer in which thermoplastic resin particles such as nylon are dispersed is provided in the surface region (patent) Reference 1).

  Furthermore, a technique has been proposed in which high toughness is expressed in a composite material to be produced by combining a resin composition whose toughness has been improved by adding a polysulfone oligomer and thermosetting resin particles (Patent Literature). 2).

  However, in the case of these techniques, a resin layer that acts as an insulating layer is generated between the prepregs that are laminated and molded. As a result, the fiber-reinforced composite material produced has a marked decrease in electrical conductivity in the thickness direction. Thus, in fiber reinforced composite materials, it has been difficult to achieve both excellent impact resistance and electrical conductivity.

  On the other hand, as a method for improving the conductivity between layers, a method of blending metal particles into a resin composition constituting a prepreg (see Patent Document 3) and a method of blending carbon particles (see Patent Document 4) are proposed. Has been. However, in these methods, a large amount of conductive material particles are added in order to improve conductivity. As a result, the resin composition that is impregnated into the reinforcing fiber during prepreg production is greatly thickened. For this reason, the manufacturability of the prepreg and the moldability of the composite material are greatly impaired. And since the composite material manufactured using such a prepreg has various defects, such as a void, there exists a problem that a mechanical physical property falls remarkably.

  As a method for achieving both impact resistance and conductivity, for example, Patent Document 5 proposes a method in which conductive particles having a diameter equivalent to the thickness of the resin layer are partially blended with the resin layer of the fiber reinforced composite material. ing. However, in this method, since there are few compounding quantities of electroconductive particle, there exists a restriction | limiting in electroconductivity improvement. Furthermore, since the conductive particles are dispersed non-uniformly, there is a problem that the volume resistivity, which is an index of conductivity, varies.

Patent Document 1 Japanese Patent No. 3661194 Patent Document 2 Japanese Patent Application Laid-Open No. 3-26750 Patent Document 3 Japanese Patent Application Laid-Open No. 6-344519 Patent Document 4 Japanese Patent Application Laid-Open No. 8-34864 Patent Document 5 Japanese Patent No. 04969363

  The object of the present invention is to solve the above-mentioned problems of the prior art, provide a fiber reinforced composite material having both excellent impact resistance and electrical conductivity in the thickness direction, and for producing a fiber reinforced composite material having excellent handleability. It is to provide a prepreg and a manufacturing method thereof.

  The present inventor uses conductive resin particles in which a conductive material is dispersed in a dispersed resin as a conductive material when the prepreg is produced by impregnating the resin composition between the reinforcing fibers constituting the reinforcing fiber sheet. I thought of that. The conductive resin particles have a larger particle size than the conventionally used conductive material particles. Therefore, even if the conductive resin particles are impregnated in the resin composition impregnated in the reinforcing fiber sheet, the viscosity of the resin composition does not increase so much. As a result, when the prepreg is produced, the resin composition can be uniformly and easily impregnated into the reinforcing fiber sheet.

  A composite material manufactured using a prepreg obtained by uniformly impregnating a reinforcing fiber sheet with a resin composition containing conductive resin particles has uniform physical properties, and has excellent impact resistance and conductivity in the thickness direction. . The present inventor has completed the present invention based on the above findings.

  The present invention for achieving the above object is as follows.

[1] A reinforcing fiber base [A] and a resin composition [B] contained between the fiber bases of the reinforcing fiber base [A].
The resin composition [B]
Matrix resin [b],
Conductive resin particles [C] containing a conductive material [D] and a dispersion resin [E];
A prepreg comprising

  [2] The prepreg according to [1], wherein the matrix resin [b] is a thermosetting resin.

  [3] The prepreg according to [1] or [2], wherein the dispersed resin [E] of the conductive resin particles [C] is a thermoplastic resin.

  [4] The prepreg according to any one of [1] to [3], wherein the dispersion resin [E] of the conductive resin particles [C] is a thermoplastic resin insoluble in the matrix resin [b].

  [5] The prepreg according to any one of [1] to [3], wherein the dispersion resin [E] of the conductive resin particles [C] is a thermoplastic resin soluble in the matrix resin [b].

  [6] Any of [1] to [3], wherein the dispersion resin [E] of the conductive resin particles [C] is a mixture of a thermoplastic resin soluble in the matrix resin [b] and an insoluble thermoplastic resin. The prepreg according to crab.

  [7] The prepreg according to any one of [1] to [6], wherein the conductive material [D] has a fibrous or particulate shape.

  [8] The conductive material [D] is carbon particles, metal particles, particles in which a core of an inorganic material is coated with a conductive material, particles in which a core of an organic material is coated with a conductive material, carbon fiber, metal fiber, Any one of [1] to [7], wherein the core of the inorganic material is at least one selected from the group consisting of a fiber coated with a conductive substance and a core of an organic material coated with a conductive substance. The prepreg as described.

  [9] A method for producing a carbon fiber reinforced composite material, comprising the steps of laminating the prepreg according to any one of [1] to [8], pressurizing and heating to mold the resin composition.

In the prepreg of the present invention, conductive resin particles in which a conductive material is dispersed in a dispersed resin are blended as a conductive material. The conductive resin particles have a larger particle size than the conventionally used conductive material particles. Therefore, even when the conductive resin particles are impregnated in the resin composition impregnated in the reinforcing fiber sheet, the viscosity of the resin composition does not increase rapidly as in the case of blending a conventional fine conductive material. As a result, when manufacturing the prepreg, the reinforcing fiber sheet can be uniformly and easily impregnated with the resin composition, and the obtained prepreg is uniform. Furthermore, the fiber reinforced composite material manufactured using this uniform prepreg has both high impact resistance and conductivity.

FIG. 1 is a schematic perspective view showing an example of the prepreg of the present invention. FIG. 2 is a conceptual diagram showing an example of conductive resin particles.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a partially omitted perspective conceptual view showing one embodiment of the prepreg of the present invention. In FIG. 1, reference numeral 100 denotes a prepreg, which is composed of a reinforcing fiber base [A] and a resin composition [B] impregnated between the reinforcing fiber bases of the reinforcing fiber base A. In FIG. 1, the reinforcing fiber base [A] is formed in a sheet shape in which a plurality of single fibers are aligned in one direction.

  The resin composition B includes at least a matrix resin b and conductive resin particles [C].

  As shown in FIG. 2, the conductive resin particle [C] includes at least a conductive material [D] and a dispersion resin E in which the conductive material [D] is dispersed.

  Each component which comprises the prepreg of this invention is demonstrated below.

Reinforcing fiber substrate [A]
Examples of the reinforcing fiber used as the reinforcing fiber base [A] include carbon fiber, glass fiber, aramid fiber, silicon carbide fiber, polyester fiber, ceramic fiber, alumina fiber, boron fiber, metal fiber, mineral fiber, and rock fiber. And slug fibers.

  Among these reinforcing fibers, carbon fibers, glass fibers, and aramid fibers are preferable. Carbon fiber is more preferable in that it has a good specific strength and specific elastic modulus, and a lightweight and high strength fiber-reinforced composite material can be obtained. Polyacrylonitrile (PAN) -based carbon fibers are particularly preferable in terms of excellent tensile strength.

  As the reinforcing fiber, as described above, a reinforcing fiber having no conductivity can also be used. Since the conductive resin particles [C] contained in the resin composition [B] to be described later are dispersed in the interior of the reinforcing fiber base (reinforced fiber layer) when molding the prepreg, the conductive resin particles [C] impart conductivity. A fiber-reinforced composite material having electrical conductivity can be obtained.

  When using a reinforcing fiber having electrical conductivity as the reinforcing fiber, the volume resistivity of the obtained fiber-reinforced composite material is greatly reduced as compared with the case of using a reinforcing fiber having no electrical conductivity.

  Therefore, from the viewpoint of obtaining a conductive fiber-reinforced composite, it is preferable to use conductive reinforcing fibers.

  When using non-conductive reinforcing fibers such as glass fibers and aramid fibers, these reinforcing fibers can be made conductive, for example, by a method such as metal plating, and thus obtained by performing such processing. It is preferable to reduce the volume resistivity of the fiber reinforced composite material. Furthermore, when further imparting conductivity to a reinforcing fiber having conductivity such as carbon fiber by a method such as metal plating, the volume resistivity of the resulting fiber-reinforced composite material can be further reduced.

  When PAN-based carbon fiber is used as the reinforcing fiber, the tensile elastic modulus is preferably 100 to 600 GPa, more preferably 200 to 500 GPa, and particularly preferably 230 to 450 GPa. The tensile strength is 2000 MPa to 10000 MPa, preferably 3000 to 8000 MPa. The diameter of the carbon fiber is preferably 4 to 20 μm, and more preferably 5 to 10 μm. By using such a carbon fiber, the mechanical properties of the resulting composite material can be improved.

  The reinforcing fiber substrate is preferably used in the form of a sheet. Examples of the reinforcing fiber base sheet include, for example, a sheet in which a large number of reinforcing fibers are aligned in one direction, bi-directional woven fabrics such as plain weave and twill weave, multiaxial woven fabric, non-woven fabric, mat, knit, braid, and reinforcing fibers. And the like.

  The thickness of the sheet-like reinforcing fiber base is preferably 0.01 to 3 mm, and more preferably 0.1 to 1.5 mm. These reinforcing fiber base sheets may contain a known sizing agent in a known content.

Resin composition [B]
The resin composition [B] is a resin composition including at least a matrix resin [b] serving as a matrix resin of a fiber-reinforced composite material and conductive resin particles [C] described later.

(Matrix resin [b])
There is no restriction | limiting in particular in matrix resin [b] used by this invention, For example, curable resin and a thermoplastic resin can be used.

  When a curable resin is used as the matrix resin [b], the curable resin is preferable because a fiber-reinforced composite material having high heat resistance can be manufactured. As the curable resin, from the viewpoint of heat resistance and mechanical properties, a thermosetting resin in which a crosslinking reaction proceeds by heat and at least partially forms a three-dimensional crosslinked structure is preferable.

  Examples of such thermosetting resins include unsaturated polyester resins, vinyl ester resins, epoxy resins, bismaleimide resins, benzoxazine resins, phenol resins, urea resins, melamine resins, and polyimide resins. Furthermore, these modified bodies and two or more kinds of blend resins can also be used. These thermosetting resins may be those that are self-cured by heating, or resins that are cured by blending a curing agent or a curing accelerator.

  Among these thermosetting resins, epoxy resins and bismaleimide resins that are excellent in the balance of heat resistance, mechanical properties, and adhesion to carbon fibers are preferable, and epoxy resins are more preferable in terms of mechanical properties, and heat resistance From this aspect, a bismaleimide resin is more preferable.

  The epoxy resin is not particularly limited, but bifunctional epoxy resins such as bisphenol type epoxy resin, alcohol type epoxy resin, biphenyl type epoxy resin, hydrophthalic acid type epoxy resin, dimer acid type epoxy resin, and alicyclic epoxy resin, Glycidyl ether type epoxy resins such as tetrakis (glycidyloxyphenyl) ethane, tris (glycidyloxyphenyl) methane, glycidylamine type epoxy resins such as tetraglycidyldiaminodiphenylmethane, naphthalene type epoxy resins, and phenols that are novolak type epoxy resins Examples thereof include novolac type epoxy resins and cresol novolac type epoxy resins.

  Furthermore, polyfunctional epoxy resins, such as a phenol type epoxy resin, etc. are mentioned. Furthermore, various modified epoxy resins such as urethane-modified epoxy resins and rubber-modified epoxy resins can also be used.

  Especially, it is preferable to use the epoxy resin which has an aromatic group in a molecule | numerator, and the epoxy resin which has either a glycidylamine structure or a glycidyl ether structure is more preferable. Moreover, an alicyclic epoxy resin can also be used suitably.

  Examples of the epoxy resin having a glycidylamine structure include N, N, N ′, N′-tetraglycidyldiaminodiphenylmethane, N, N, O-triglycidyl-p-aminophenol, N, N, O-triglycidyl-m-. Examples include aminophenol, N, N, O-triglycidyl-3-methyl-4-aminophenol, and various isomers of triglycidylaminocresol.

  Examples of the epoxy resin having a glycidyl ether structure include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, phenol novolac type epoxy resins, and cresol novolac type epoxy resins.

  These epoxy resins may have a non-reactive substituent in the aromatic ring structure or the like as necessary. Examples of non-reactive substituents include alkyl groups such as methyl, ethyl and isopropyl, aromatic groups such as phenyl, alkoxyl groups, aralkyl groups, and halogen groups such as chlorine and bromine.

  Examples of the bisphenol type epoxy resin include bisphenol A type resin, bisphenol F type resin, bisphenol AD type resin, bisphenol S type resin and the like. Specifically, jER815 (product name), jER828 (product name), jER834 (product name), jER1001 (product name), jER807 (product name) manufactured by Japan Epoxy Resin Co., Ltd., and EPOMIC R-710 (product name) manufactured by Mitsui Petrochemical Co., Ltd. ), EXA1514 (trade name) manufactured by Dainippon Ink and Chemicals, and the like.

  Examples of the alicyclic epoxy resin include Araldite CY-179 (trade name), CY-178 (trade name), CY-182 (trade name), and CY-183 (trade name) manufactured by Huntsman. .

  As a phenol novolac type epoxy resin, Japan Epoxy Resin's jER152 (trade name), jER154 (trade name), Dow Chemical's DEN431 (trade name), DEN485 (trade name), DEN438 (trade name), DIC Corporation As cresol novolak type epoxy resin such as Epicron N740 (trade name), Araldite ECN1235 (trade name), ECN1273 (trade name), ECN1280 (trade name), EOCN102 (trade name), EOCN103, manufactured by Nippon Kayaku Co., Ltd. (Product name), EOCN104 (Product name), etc. are exemplified.

  Examples of the various modified epoxy resins include Adeka Resin EPU-6 (trade name) and EPU-4 (trade name) manufactured by Asahi Denka as urethane-modified bisphenol A epoxy resins.

  These epoxy resins can be appropriately selected and used alone or in combination of two or more. Among these, bifunctional epoxy resins represented by bisphenol type include various grades of resins from liquid to solid depending on the difference in molecular weight. Therefore, these resins are conveniently blended for the purpose of adjusting the viscosity of the prepreg matrix resin b.

  A conventionally known bismaleimide compound can be used as a bismaleimide compound (hereinafter also referred to as BMI) used as a bismaleimide resin. For example, the bismaleimide compound represented by following formula (1) is mentioned.

[In Formula (1), R _{1 to} R ₄ each independently include —H, —CH ₃ , —C ₂ H ₅ , —C ₃ H ₇ , —F, —Cl, —Br, and —I. Represents a group selected from the group; X will be described later. ]
As the bismaleimide resin composition, it is preferable to use a bismaleimide compound containing an aromatic ring structure and a bismaleimide compound not containing an aromatic ring structure in combination. By using these together, the handleability of the obtained prepreg can be improved.

  As the bismaleimide compound containing an aromatic ring structure (hereinafter referred to as “aromatic bismaleimide compound”), for example, a compound in which X in the formula (1) is a structure described in the following formulas (2) to (8) is used. Can be mentioned.

Wherein _{(5), R} 5 _{is, -CH 2 -, - C (} CH 3) 2 -, - O -, - SO 2 - represents a. ]

Wherein (6), _{R 5 is, -CH 2 -, - C (} CH 3) 2 -, - O -, - SO 2 - represents a. R _{6 to} R ₉ are each independently a group selected from the group consisting of —H, —CH ₃ , —C ₂ H ₅ , —C ₃ H ₇ , —F, —Cl, —Br, and —I. Represents. ]

Wherein (7), _{R 5 is, -CH 2 -, - C (} CH 3) 2 -, - O -, - SO 2 - represents a. ]

Wherein _{(8), R} 10 ~R ₁₁ are each _{independently, -CH 2 -, - C (} CH 3) 2 -, - O -, - SO 2 - represents a. In formula (8), n is 0-0.5. ]

Examples of such aromatic bismaleimide compounds include N, N′-4,4′-diphenylmethane bismaleimide, N, N′-4,4′-diphenyl ether bismaleimide, N, N′-m-phenylene bismaleimide, N, N′-p-phenylene bismaleimide, N, N′-m-toluylene bismaleimide, N, N′-4,4′-biphenylene bismaleimide, N, N′-4,4 ′-(3 3′-dimethylbiphenylene) bismaleimide, 2,2-bis [4- (4-maleimidophenoxy) phenyl] propane, 3,3′-dimethyl-5,5′-diethyl-4,4′-diphenylmethane bismaleimide, Examples include 4-methyl-1,3-phenylene bismaleimide, N, N′-4,4′-diphenylsulfone bismaleimide, N, N′-4,4′-benzophenone bismaleimide, and the like. It is possible.

From the viewpoint of heat resistance of the fiber-reinforced composite material after heat curing, N, N′-4,4′-diphenylmethane bismaleimide, N, N′-4,4′-diphenyl ether bismaleimide, N, N′-m -Toluylene bismaleimide, 2,2-bis [4- (4-maleimidophenoxy) phenyl] propane, 4-methyl-1,3-phenylene bismaleimide, N, N'-4,4'-diphenylsulfone bismaleimide N, N′-4,4′-benzophenone bismaleimide, N, N′-4,4′-diphenylmethane bismaleimide, N, N′-4,4′-diphenyl ether bismaleimide, N, N′— Particularly, m-toluylene bismaleimide, 2,2-bis [4- (4-maleimidophenoxy) phenyl] propane, and 4-methyl-1,3-phenylenebismaleimide Masui. These aromatic bismaleimide compounds may be used alone or in combination of two or more.

As the bismaleimide compound not containing an aromatic ring structure (hereinafter referred to as “aliphatic bismaleimide compound”), for example, X in the formula (1) has a structure described in the following formulas (9) to (11). Compounds.

[In Formula (9), n is an integer of 10 or less, and 1, 2, 3, 4, and 6 are preferable. ]

  Examples of such aliphatic bismaleimide compounds include 1,6′-bismaleimide- (2,2,4-trimethyl) hexane, hexamethylenediamine bismaleimide, N, N′-1,2-ethylenebismaleimide, N , N′-1,3-propylene bismaleimide and N, N′-1,4-tetramethylene bismaleimide. 1,6'-bismaleimide- (2,2,4-trimethyl) hexane and hexamethylenediamine bismaleimide are particularly preferred. The aliphatic bismaleimide compound may be used alone or in combination of two or more.

  The bismaleimide resin composition preferably contains a bismaleimide compound curing agent in addition to the bismaleimide compound. As a hardening | curing agent of a bismaleimide compound, an alkenyl phenol and / or an alkenyl phenol ether compound are mentioned, for example.

  An alkenyl phenol ether is obtained by a reaction between a phenol compound and an alkenyl halide, and alkenyl phenol is obtained by Claisen transition of the alkenyl phenol ether (Japanese Patent Laid-Open No. 52-994). The alkenylphenol and / or alkenylphenol ether compound contained in the bismaleimide resin composition may contain the transition structure.

  As the alkenylphenol and / or alkenylphenol ether, allylphenol, methallylphenol or an ether thereof is preferable. More preferably, the alkenylphenol or alkenylphenol ether is a compound of the following formulas (12) to (16).

[In Formula (12), R < ₁₂ >, R < ₁₃ >, R < ₁₄ > is respectively independently hydrogen or a C2-C10 alkenyl group, Preferably they are an allyl group or a propenyl group. However, at least one of R ₁₂ , R ₁₃ , and R ₁₄ is an alkenyl group having 2 to 10 carbon atoms. ]

[In the formula (13), R ₁₅ represents a direct bond, —CH ₂ —, —C (CH ₃ ) ₂ —, —O—, —S—, —SO— or —SO ₂ —. R ₁₆ , R ₁₇ , R ₁₈ and R ₁₉ are each independently hydrogen or an alkenyl group having 2 to 10 carbon atoms, preferably an allyl group or a propenyl group. However, at least one of R ₁₆ , R ₁₇ , R ₁₈ , and R ₁₉ is an alkenyl group having 2 to 10 carbon atoms. ]
Of the formula (13), compounds of the following formula (14) are particularly preferred.

[In the formula (14), R ₁₅ represents a direct bond, —CH ₂ —, —C (CH ₃ ) ₂ —, —O—, —S—, —SO— or —SO ₂ —. ]

[In the formula (15), R ₂₀ and R ₂₁ are a direct bond, —CH ₂ —, —C (CH ₃ ) ₂ —, —O—, —S—, —SO— or —SO ₂ —. R ₂₂ , R ₂₃ , R ₂₄ , R ₂₅ , R ₂₆ , R ₂₇ are each independently hydrogen, an alkyl group having 1 to 4 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms, preferably an allyl group Or it is a propenyl group. However, at least one of R ₁₀ , R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ , and R ₁₅ is an alkenyl group having 2 to 10 carbon atoms. P is an integer of 0-10. ]

[In the formula (16), R ₁₅ represents a direct bond, —CH ₂ —, —C (CH ₃ ) ₂ —, —O—, —S—, —SO— or —SO ₂ —. R ₂₈ and R ₂₉ are each independently hydrogen, an alkyl group having 1 to 4 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms, and preferably an allyl group or a propenyl group. However, at least one of R ₂₈ and R ₂₉ is an alkenyl group having 2 to 10 carbon atoms. ]

Examples of the alkenylphenol or alkenylphenol ether compound include O, O′-diallylbisphenol A, 4,4′-dihydroxy-3,3′-diallyldiphenyl, bis (4-hydroxy-3-allylphenyl) methane, 2,2′-bis (4-hydroxy-3,5-diallylphenyl) propane, 2,2′-diallylbisphenol F, 4,4′-dihydroxy-3,3′-diallyldiphenyl ether, 4,4′-bis -O-propenylphenoxy-benzophenone and the like can be mentioned. Among these, since the glass transition point of the resin after heat curing is high, O, O′-diallylbisphenol A, 2,2′-bis (4-hydroxy-3,5-diallylphenyl) propane, 2,2 ′ -Diallyl bisphenol F etc. are preferable. O, O′-diallylbisphenol A is particularly preferable because it lowers the viscosity of the resin composition. In the present resin composition, alkenylphenol and / or alkenylphenol ether may be used alone or in combination of two or more.

  When the bismaleimide resin composition contains an alkenylphenol and / or an alkenylphenol ether compound as appropriate in an arbitrary range, the viscosity is adjusted and good moldability can be obtained. Moreover, the present resin composition can be sufficiently impregnated into the reinforcing fiber base material and can be sufficiently adhered to the reinforcing fiber base material.

  In the bismaleimide resin composition, part or all of the aromatic bismaleimide compound and / or the aliphatic bismaleimide compound may be dissolved in the alkenylphenol and / or alkenylphenol ether compound.

(Conductive resin particles [C])
The conductive resin particles [C] are particles composed of a conductive material [D] and a dispersed resin [E] obtained by mixing and dispersing the conductive material [D]. The shape of the conductive resin particles is not particularly limited. Arbitrary shapes such as particles having a certain shape such as a spherical shape, a polygonal column shape, a cubic shape, a rod shape, and a fiber shape, and irregular particles having no specific shape such as a crushed material can be adopted. Particularly preferable shapes are a spherical shape, an indefinite shape, and a fibrous shape.

  The average particle diameter of the conductive resin particles excluding the fibrous conductive resin particles is preferably 0.01 to 100 μm, and more preferably 0.1 to 50 μm.

  When the conductive resin particles are fibrous, the length is preferably 1 to 500 μm, and more preferably 10 to 200 μm. The diameter is preferably 0.001 to 100 μm, and more preferably 0.01 to 50 μm.

  The dispersion resin [E], which is a constituent component of the conductive resin particles [C], is made of a thermosetting resin and / or a thermoplastic resin. From the viewpoint of mechanical properties of the obtained fiber-reinforced composite material, a thermoplastic resin is preferable.

  The thermoplastic resin used for the dispersion resin [E] includes polyethersulfone (PES), polyetherimide (PEI), polyimide, polyamideimide, polysulfone, polycarbonate, polyetheretherketone, nylon 6, nylon 12, Examples thereof include polyamide such as crystalline nylon, aramid, arylate, and polyester carbonate. Among these, polyimide, polyetherimide (PEI), polyethersulfone (PES), polysulfone, and polyamideimide are more preferable from the viewpoint of heat resistance.

  Terminal-modified polyester and terminal-modified PES (Sumika Excel 5003P (trade name)) can also be used. In addition, the thermoplastic resin includes a rubber component. Typical examples of the rubber component include rubber components represented by carboxy-terminated styrene butadiene rubber and carboxy-terminated hydrogenated acrylonitrile butadiene rubber. These thermoplastic resins may be used independently or may use 2 or more types together in arbitrary ratios.

  These thermoplastic resins can be broadly classified into soluble thermoplastic resins that are soluble in the matrix resin [b] and insoluble thermoplastic resins that are insoluble in the matrix resin [b].

  The soluble thermoplastic resin is a thermoplastic resin that is partially or wholly dissolved in the matrix resin [b] by heating. The heat-soluble thermoplastic resin in the present invention refers to a thermoplastic resin that is partially or wholly dissolved in the matrix resin [b], particularly in the prepreg manufacturing process and the fiber-reinforced composite material molding process. More specifically, the matrix resin can be arbitrarily set at the maximum processing temperature (generally 100 to 190 ° C.) in the prepreg manufacturing process and / or the fiber-reinforced composite material molding process using the prepreg. It is a thermoplastic resin in which part or all of [b] is dissolved. The soluble thermoplastic resin used in the present invention is preferably a resin that dissolves in the matrix resin [b] at 80% by mass or more under a temperature condition of 190 ° C.

  When an epoxy resin or a bismaleimide resin is used as the matrix resin [b], examples of the soluble thermoplastic resin include polyethersulfone, polysulfone, polyetherimide, and polycarbonate. These may be used alone or in combination of two or more.

  The insoluble thermoplastic resin is a thermoplastic resin that does not dissolve in the matrix resin [b] even when heated, and in particular, does not dissolve in the matrix resin [b] in the prepreg manufacturing process and the fiber-reinforced composite material molding process. Say thermoplastic resin. More specifically, the fact that the thermoplastic resin does not dissolve in the matrix resin [b] means that the thermoplastic resin is charged into the matrix resin [b] and is a processing temperature at the time of general composite material molding of 100 to 190 ° C. In this case, the particle size does not change when the mixture is stirred. The insoluble thermoplastic resin used in the present invention is preferably a resin whose particle size does not change when the matrix resin [b] is stirred at a temperature of 190 ° C.

  When a soluble thermoplastic resin is used as the dispersion resin [E] used for the conductive resin particles [C], the dispersion resin [E] is contained in the matrix resin in the prepreg manufacturing process or the fiber-reinforced composite material molding process. The fine conductive material [D] dissolved in the conductive resin particles [C] is released into the matrix resin [b] and dispersed in the matrix resin [b].

  Usually, the matrix resin [b] has fluidity under the condition that the soluble thermoplastic resin is dissolved in the matrix resin [b]. For this reason, the conductive material [D] discharged into the matrix resin [b] is uniformly dispersed in the matrix resin [b]. As a result, a fiber-reinforced composite material with more uniform conductivity can be obtained.

  On the other hand, when an insoluble thermoplastic resin is used as the dispersion resin [E] used for the conductive resin particles [C], the conductive resin particles [C] are fibers obtained by molding the prepreg even in the prepreg. Even in the reinforced composite material, it can exist while maintaining its shape. In that case, since the conductive resin particles [C] act as a conductive path in the thickness direction in the fiber reinforced composite material, the obtained fiber reinforced composite material is given high conductivity.

  It is also preferred that the thermoplastic resin contained in the conductive resin particles [C] contains both a soluble thermoplastic resin and an insoluble thermoplastic resin.

  The soluble thermoplastic resin and the insoluble thermoplastic resin used in the present invention are both conventionally known thermoplastic resins.

  When an epoxy resin or a bismaleimide resin is used as the matrix resin [b], examples of insoluble thermoplastic resins include polyamide, polyacetal, polyphenylene oxide, polyphenylene sulfide, polyester, polyamideimide, polyimide, polyetherketone, polyetheretherketone, Examples include polyethylene naphthalate, polyether nitrile, and polybenzimidazole. Among these, polyamide, polyamideimide, and polyimide are preferable because of high toughness and good heat resistance.

  These insoluble thermoplastic resins may be used alone or in combination of two or more. Moreover, these copolymers can also be used. For example, polyimide and polyamide are particularly excellent in the effect of imparting toughness to the composite material.

  In particular, amorphous polyimide, nylon 6 (registered trademark) (polyamide obtained by ring-opening polycondensation reaction of caprolactam), nylon 12 (polyamide obtained by ring-opening polycondensation reaction of lauryl lactam), amorphous nylon The use of a polyamide such as (also called transparent nylon, which does not cause crystallization of the polymer or has a very slow crystallization rate of the polymer) can improve the heat resistance of the resulting composite material.

(Conductive material [D])
The conductive material contained in the conductive resin particles [C] may be conductive particles that function as an electrically good conductor, and is not limited to particles composed of only a conductor. Preferably, the particles have a volume resistivity of 10 to 10 ⁻⁹ Ωcm, more preferably 1 to 10 ⁻⁹ Ωcm, and particularly preferably 10 ⁻¹ to 10 ⁻⁹ Ωcm. When the volume resistivity exceeds 10 Ωcm, the resulting carbon fiber reinforced composite material may have insufficient conductivity.

  Examples of the conductive material include conductive polymer particles such as polyacetylene particles, polyaniline particles, polypyrrole particles, polythiophene particles, polyisothianaphthene particles and polyethylenedioxythiophene particles, carbon particles, carbon fiber particles, metal particles, and inorganic For example, particles in which a core material made of a material or an organic material is coated with a conductive substance can be used.

  Among the above conductive materials, particles formed by coating a core material of carbon particles, metal particles, an inorganic material or an organic material with a conductive material are preferable because they exhibit high conductivity and stability.

  Examples of carbon particles include carbon nanofibers including carbon black, expanded graphite, flake graphite, graphite powder, graphite particles, graphene sheets, carbon milled fibers, carbon nanotubes, and vapor grown carbon fibers (VGCF). These may be used, and these may be used alone or in combination. Of these, carbon black and carbon milled fiber, which are inexpensive and have a high conductive effect, are preferably used.

  As carbon black, for example, furnace black, acetylene black, thermal black, channel black, ketjen black and the like can be used, and carbon black obtained by blending two or more of these is also preferably used. Examples of the carbon milled fiber include PAN-based carbon fiber, pitch-based carbon fiber, and phenol-based carbon fiber milled fiber. Of these, milled fiber of pitch-based carbon fiber is particularly preferable. The carbon content of the carbon milled fiber is preferably 94% by mass or more. When the carbon content is less than 94% by mass, the conductivity of the resulting composite material tends to decrease.

  As metal particles, corrosion caused by potential difference between metal particles and carbon fibers can be prevented, so platinum, gold, silver, copper, tin, nickel, titanium, cobalt, zinc, iron, chromium, aluminum, or these An alloy having a main component is preferable. Further, tin oxide, indium oxide, indium oxide / tin (ITO) and the like are also preferable. Among these, platinum, gold, silver, copper, tin, nickel, titanium, or an alloy containing these as a main component is particularly preferable because of high conductivity and chemical stability.

  As a method for coating the core material made of an inorganic material or an organic material with a conductor to make the core material conductive, metal plating and mechanochemical bonding methods are preferable.

  As a method of performing metal plating, there are a wet plating method and a dry plating method. As the wet plating method, methods such as electroless plating, displacement plating, and electroplating can be employed. The method by electroless plating is preferable because it is possible to plate the nonconductor. As dry plating, methods such as vacuum deposition, plasma CVD (chemical vapor deposition), photo CVD, ion plating, and sputtering can be adopted, but a method by sputtering is possible because excellent adhesion can be obtained even at low temperatures. Is preferred.

  Mechanochemical bonding is a method in which a plurality of different material particles are mechanically combined at a molecular level by applying mechanical energy, and a strong nano bond is created at the interface to create composite fine particles. The core material is preferably coated with metal particles, carbon nanomaterial, and vapor grown carbon fiber (VGCF).

  The average particle diameter of the conductive material [D] is preferably 0.01 to 50 μm, and more preferably 0.01 to 10 μm. When the average particle diameter of the conductive material [D] is 0.01 to 50 μm and the dispersion resin [E] is soluble, the dispersion resin dissolves during molding and a part of the conductive material [D] forms a fiber layer during molding. Disperse moderately. As a result, the conductivity of the resulting composite material is likely to improve.

  Further, the ratio of the average particle diameter of the conductive material [D] contained in the conductive resin particles [C] to the average particle diameter of the conductive resin particles [C] (average particle diameter of the conductive material [D] / conductivity When the average particle diameter of the resin particles [C] is preferably 1/2 to 1/1000, more preferably 1/10 to 1/100, both the impact resistance and conductivity of the resulting composite material are obtained. It is easier to obtain an improvement effect.

  It is preferable to mix | blend so that the compounding quantity of electrically conductive material [D] may be 0.2-100 mass parts with respect to 100 mass parts of resin contained in conductive resin particle [C], and 1-50 mass parts. Is more preferable, and 5 to 20 parts by mass is particularly preferable. When the blending amount of the conductive material [D] is 0.2 to 100 parts by mass, the effect of improving both the impact resistance and the conductivity of the composite material by the conductive resin particles [C] is particularly easily obtained. When the amount is less than 0.2 parts by mass, it may be difficult to obtain an effect of improving the conductivity of the obtained composite material. When the amount exceeds 100 parts by mass, the viscosity of the dispersion resin [E] is remarkably increased, the productivity is remarkably deteriorated, and the conductive material is present in a large amount. Therefore, depending on the resin composition using the conductive resin particles. The mechanical properties of the composite material produced from the prepreg may be deteriorated.

(Method for producing conductive resin particle [C])
The manufacturing method of conductive resin particle [C] is not specifically limited, A conventionally well-known kneading method etc. can be used. The kneading temperature applied during the production of the conductive resin particles [C] is the softening temperature ± 80 ° C. of the dispersion resin [E] to be blended. When the temperature exceeds + 80 ° C., thermal degradation of the resin or partial curing reaction starts, and the mechanical properties of the conductive resin particles [C] obtained and the prepregs or molded products produced using the conductive resin particles may be significantly reduced. is there. If it is lower than −80 ° C., the resin viscosity becomes high, and kneading may become difficult substantially. Preferably it is +/- 60 degreeC, More preferably, it is +/- 40 degreeC.

  A conventionally well-known thing can be used as a kneading machine apparatus. Specific examples include an extruder, a Banbury mixer, a mixing container equipped with stirring blades, a horizontal mixing tank, and the like. The kneading of each component can be performed in the air, in a vacuum, or in an inert gas atmosphere. In particular, when kneading is performed in the air, an atmosphere in which temperature and humidity are controlled is preferable. Although not particularly limited, for example, it is preferably kneaded in a low temperature atmosphere of 30 ° C. or lower, a temperature controlled at a constant level, or a relative humidity of 50% RH or lower.

  Kneading may be performed in one stage or in multiple stages. Moreover, the mixing order of each component of a resin composition is not limited. The whole or part of the resin-soluble thermoplastic resin can be previously dissolved in an epoxy resin and kneaded. Moreover, you may mix as a dispersed particle in an epoxy resin in the state of a powder.

  These mixtures obtained by kneading the conductive material [D] and the dispersion resin [E] have a desired particle size if necessary. As a method for obtaining a desired particle size, a known method using a jet mill, a hammer mill, a nano jet mizer, or the like can be employed.

(Other additives of resin composition [B])
[Curing agent]
When using curable resin as matrix resin [b], the hardening | curing agent which hardens resin [b] may be mix | blended with resin composition [B] as needed. As the curing agent, a known curing agent that cures the matrix resin [b] is used.

  For example, examples of the curing agent used when an epoxy resin is used as the curable resin include dicyandiamide, various isomers of aromatic amine curing agents, and aminobenzoic acid esters. Dicyandiamide is preferable because of excellent storage stability of the prepreg. In addition, aromatic diamine compounds such as 4,4′-diaminodiphenylsulfone, 3,3′-diaminodiphenylsulfone, and 4,4′-diaminodiphenylmethane and derivatives having non-reactive substituents have good heat resistance. From the viewpoint of providing a cured product. Here, the non-reactive substituent is the same as the non-reactive substituent described in the description of the epoxy resin.

  As the aminobenzoic acid esters, trimethylene glycol di-p-aminobenzoate and neopentyl glycol di-p-aminobenzoate are preferably used. Composite materials cured using these are inferior in heat resistance to various isomers of diaminodiphenylsulfone, but are excellent in tensile elongation. Therefore, the type of curing agent to be used is appropriately selected according to the use of the composite material.

  The amount of the curing agent contained in the resin composition [B] is at least an amount suitable for curing the matrix resin [b] blended in the resin composition [B]. What is necessary is just to adjust suitably according to the kind of. The blending amount can be appropriately used in a desired blending amount in consideration of the presence / absence and addition amount of a curing agent / curing accelerator, the chemical reaction stoichiometry with the epoxy resin, the curing rate of the composition, and the like. From the viewpoint of storage stability, it is preferable to add 30 to 100 parts by mass of the curing agent, and more preferably 30 to 70 parts by mass with respect to 100 parts by mass of the matrix resin [b] contained in the resin composition [B]. .

  As the curing agent, DDS microencapsulated with a coating agent (for example, DDS coat 10 (manufactured by Matsumoto Yushi Co., Ltd.)) can also be used. In order to prevent the mc-DDS from reacting with an uncured epoxy resin at room temperature, the surface layer of the DDS particles is made less reactive with the epoxy resin by physical and chemical bonding, specifically, polyamide, Coated with a coating agent such as modified urea resin, modified melamine resin, polyolefin, polyparaffin (including modified products). These coating agents may be used alone or in combination, and DDS microencapsulated with various coating agents other than those described above can also be used.

[Thermoplastic resin]
When a low-viscosity curable resin is used as the matrix resin [b], a thermoplastic resin may be blended to give an appropriate viscosity to the resin composition [B]. The thermoplastic resin blended in the resin composition [B] for viscosity adjustment also has an effect of improving the impact resistance of the finally obtained fiber-reinforced composite material.

  The amount of the thermoplastic resin blended in the resin composition [B] varies depending on the type of the matrix resin [b] used in the resin composition [B], and the viscosity of the resin composition [B] is appropriate as described later. What is necessary is just to adjust suitably so that it may become a value. Usually, it is preferable to mix the thermoplastic resin in an amount of 5 to 100 parts by mass with respect to 100 parts by mass of the matrix resin [b] contained in the resin composition [B].

  The resin composition [B] preferably has a minimum viscosity of 10 to 450 poise at 80 ° C., more preferably a minimum viscosity of 50 to 400 poise. When the minimum viscosity of the resin composition [B] is 10 poise or more, the effect of localizing the conductive resin particles [C] contained in the resin composition [B] in the vicinity of the surface of the prepreg becomes high, and the prepreg is cured. The carbon fiber reinforced composite material obtained in this way tends to have higher conductivity in the thickness direction. When the minimum viscosity of the resin composition [B] exceeds 450 poise, the viscosity of the resin composition becomes too high, and the impregnation property of the resin composition “B” with respect to the reinforcing fiber base [A] is deteriorated at the time of manufacturing the prepreg. This is not preferable because the handleability deteriorates.

  In addition to the above components, the resin composition [B] of the present invention may be used as appropriate, such as an acid anhydride, Lewis acid, dicyandiamide (DICY), and imidazoles, as long as the object and effect of the present invention are not impaired. Various additives such as a basic curing agent, a urea compound, and an organic metal salt can be included.

Specifically, examples of the acid anhydride include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like. Examples of the Lewis acid include boron trifluoride salts, and more specifically, BF ₃ monoethylamine, BF ₃ benzylamine, and the like. Examples of imidazoles include 2-ethyl-4-methylimidazole, 2-ethylimidazole, 2,4-dimethylimidazole, and 2-phenylimidazole. Further, examples include 3- [3,4-dichlorophenyl] -1,1-dimethylurea (DCMU) that is a urea compound, and Co [III] acetylacetonate that is an organic metal salt. Examples of the reactive diluent include reactive diluents such as polypropylene diglycol / diglycidyl ether and phenyl glycidyl ether.

[Other conductive materials]
The resin composition [B] of the present invention may contain conductive particles other than the conductive particles [C] as necessary. As electroconductive particle, the same thing as the above-mentioned electrically conductive material [D] can be used. It is preferable to mix | blend so that the compounding quantity of electroconductive particle may be 0.2-20 mass parts with respect to 100 mass parts of matrix resin [b] contained in resin composition [B], and 1-15 masses. Part is more preferable, and 5 to 15 parts by mass is particularly preferable.

  When the amount is less than 0.2 parts by mass, it may be difficult to obtain an effect of improving the conductivity of the obtained composite material. Moreover, when it exceeds 20 mass parts, the viscosity of a resin composition may become remarkably high and a handleability may deteriorate remarkably. Moreover, compared with the case where it contains electroconductive particle so that the addition amount of electroconductive particle which occupies for the whole resin composition may become comparable, there exists a tendency for the electroconductivity of the composite material obtained to become low.

(Production method of resin composition [B])
The resin composition [B] is preferably prepared by mixing the conductive resin particles [C] produced as described above and the matrix resin [b], and the conductive resin particles [C] into the matrix resin [b]. Can be produced by uniformly dispersing.

  The method for producing the resin composition [B] is not particularly limited, and any conventionally known method may be used. For example, when an epoxy resin is used as the matrix resin [b], the kneading temperature applied during the production of the resin composition can be in the range of 10 to 160 ° C. When the temperature exceeds 160 ° C., thermal deterioration of the epoxy resin or partial curing reaction may start, and the storage stability of the resulting resin composition and the prepreg produced using the resin composition may decrease. When the temperature is lower than 10 ° C., the viscosity of the epoxy resin composition is high, and kneading may be substantially difficult. Preferably it is 20-130 degreeC, More preferably, it is the range of 30-110 degreeC.

  A conventionally well-known thing can be used as a kneading machine apparatus. Specific examples include a roll mill, a planetary mixer, a kneader, an extruder, a Banbury mixer, a mixing vessel provided with a stirring blade, a horizontal mixing vessel, and the like. Each component can be kneaded in the air or in an inert gas atmosphere. When kneading is performed in the air, an atmosphere in which temperature and humidity are controlled is preferable. Although not particularly limited, for example, it is preferable to knead in a temperature controlled at a constant temperature of 30 ° C. or lower or in a low humidity atmosphere with a relative humidity of 50% RH or lower.

(Prepreg)
Next, the aspect of the prepreg of the present invention will be described. The prepreg of the present invention is formed by impregnating the resin composition [B] in the gaps between the fiber bases constituting the reinforcing fiber base [A].

  It is preferable that the content rate (RC) of resin composition [B] is 15-60 mass% on the basis of the total mass of a prepreg. When the content is less than 15% by mass, voids or the like are generated in the obtained composite material, and the mechanical properties may be deteriorated. When the content exceeds 60% by mass, the reinforcing effect by the reinforcing fibers becomes insufficient, and the mechanical properties relative to mass may be substantially low. Preferably, the content is 20 to 50% by mass, more preferably 25 to 50% by mass.

  Here, when the matrix resin [b] is an epoxy resin, the content ratio (RC) of the composition is that the prepreg is immersed in sulfuric acid and heated as necessary to decompose the epoxy resin and reduce the mass. The ratio calculated from the amount of mass change that occurs can be the content of the resin composition [B].

  Specifically, first, a prepreg is cut out to 100 mm × 100 mm to produce a test piece, and its mass is measured. Next, this prepreg test piece is immersed or boiled in sulfuric acid to decompose and elute the resin component. Thereafter, the remaining fibers are filtered off, washed with sulfuric acid, dried, and the mass of the dried fibers is measured. Finally, the content rate of the epoxy resin composition is calculated from the mass change before and after the sulfuric acid decomposition operation.

  The form of the prepreg of the present invention is not particularly limited as long as the reinforcing fiber base [A] is impregnated with the resin composition [B]. However, a prepreg comprising a reinforcing fiber layer composed of reinforcing fibers and an epoxy resin composition impregnated between the reinforcing fibers, and a resin coating layer coated on the surface of the reinforcing fiber layer is preferable. The thickness of the resin coating layer is preferably 2 to 50 μm. When the thickness of the resin coating layer is less than 2 μm, the tackiness becomes insufficient, and the molding processability of the prepreg may be significantly lowered. When the thickness of the resin coating layer exceeds 50 μm, it is difficult to wind the prepreg into a roll with a uniform thickness, and the molding accuracy may be significantly reduced. The thickness of the resin coating layer is more preferably 5 to 45 μm, and particularly preferably 10 to 40 μm.

  The method for producing the prepreg of the present invention is not particularly limited, and any conventionally known method can be adopted. Specifically, a hot melt method or a solvent method can be suitably employed.

  In the hot melt method, the resin composition [B] is coated on a release paper in the form of a thin film to form a resin composition film, and then the formed film is peeled from the release paper to form a resin composition film. Then, the resin composition film is laminated on the reinforcing fiber base and heated under pressure to impregnate the reinforcing fiber base with the resin composition.

  The method for forming the resin composition into a resin composition film is not particularly limited, and any conventionally known method can be used. Specifically, it can be obtained by casting and casting a resin composition on a support such as a release paper or a film using a die extrusion, an applicator, a reverse roll coater, a comma coater or the like. The resin temperature for producing the film is appropriately determined according to the composition and viscosity of the resin for producing the film. Specifically, the same temperature conditions as the kneading temperature in the above-described method for producing an epoxy resin composition are preferably used. The impregnation can be performed in multiple stages at an arbitrary pressure and temperature in a plurality of times instead of once.

  The solvent method is a method in which an epoxy resin composition is made into a varnish using an appropriate solvent, and this reinforcing varnish is impregnated with the varnish. Among these conventional methods, the prepreg of the present invention can be preferably produced by a hot melt method which is a conventionally known production method.

  The impregnation pressure when the resin composition [B] is impregnated into the reinforcing fiber base using the resin composition film is appropriately determined in consideration of the viscosity and resin flow of the resin composition.

  When the epoxy resin is used as the matrix resin [b] and the reinforcing fiber substrate is impregnated with the epoxy resin composition film by the hot melt method, the impregnation temperature is preferably in the range of 50 to 150 ° C. When the impregnation temperature is less than 50 ° C., the epoxy resin composition film has a high viscosity and may not be sufficiently impregnated into the reinforcing fiber base [A]. When the impregnation temperature is 150 ° C. or higher, a curing reaction of the epoxy resin composition starts to occur, and the storage stability of the obtained prepreg may be lowered, or the drapability may be lowered. The impregnation temperature is more preferably 60 to 145 ° C, and particularly preferably 70 to 140 ° C.

  The prepreg obtained using the above method is laminated according to the purpose, molded and cured, and a fiber-reinforced composite material is produced. This manufacturing method itself is known. The fiber reinforced composite material produced using the present prepreg has high moisture and heat resistance properties and further excellent impact resistance. Accordingly, the fiber reinforced composite material produced using the present prepreg is suitable for use in applications such as aircraft structural materials.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited to an Example. The components and test methods used in the examples and comparative examples are described below.

〔component〕
(Reinforced fiber substrate)
-The tensile strength and elastic modulus of the carbon fiber strand (Tenax IMS60 (brand name)) by Toho Tenax used were as follows.

・ Tensile strength: 5800 MPa (590 kgf / mm ² )
-Elastic modulus 290 GPa (30 tf / mm ² )
[Epoxy resin composition]
(Epoxy resin)
・ Glycidylamine type epoxy resin (trifunctional group) [Araldite MY0600 (trade name) manufactured by Huntsman Advanced Materials, Inc.] (MY0600)
・ Glycidylamine type epoxy resin (4 functional groups) [Araldite MY721 (trade name) manufactured by Huntsman Advanced Materials, Inc.] (MY721)
(Epoxy resin curing agent)
・ 3,3′-diaminodiphenylsulfone [Aromatic amine curing agent manufactured by Nippon Synthetic Processing Co., Ltd.] (3,3′-DDS)
・ 4,4′-Diaminodiphenylsulfone [Aromatic amine curing agent manufactured by Wakayama Seika Co., Ltd.] (4,4′-DDS)
[Bismaleimide resin composition]
(Aromatic bismaleimide compounds)
N, N′-4,4′-diphenylmethane bismaleimide [Matrimid 5292 A (trade name) manufactured by Huntsman Advanced Materials, Inc.] (Matrimid 5292A)
(Alkenylphenol)
O, O'-diallylbisphenol A, [Matrimid 5292 B (trade name) manufactured by Huntsman Advanced Materials, Inc.] (Matrimid 5292B)
[Conductive resin particles]
The conductive resin particles [C] used in this example were prepared by the following method.

・ Conductive resin particles a
The dispersion resin [E] is a polyamide resin (grill amide TR-55 (manufactured by Ems Chemie)) which is an epoxy resin-insoluble thermoplastic resin, and the carbon black (Ketjen black EC300J (manufactured by Lion)) is used as the conductive material [D]. Using.

  The polyamide resin / conductive material was uniformly mixed using a tumbler at a mass ratio of 90/10, and then pelletized using a co-rotating twin-screw kneading extruder with a 25 mmφ vent (HK-25D). The cylinder temperature was 280 ° C., and pelletization was performed while degassing at a vacuum degree of 10 mm H g. The obtained pellets were pulverized by a jet mill to obtain conductive resin particles a (average particle size 20 μm).

・ Conductive resin particles b
Conductive resin particles b (average particle diameter 20 μm) were obtained in the same manner as the conductive resin particles a except that the polyamide resin / conductive material mass ratio was changed to 85/15.

・ Conductive resin particles c
The same as the conductive resin particles a except that carbon milled fiber (DIALEAD: K223HM (manufactured by Mitsubishi Plastics)) was used as the conductive material [D] and the mass ratio of polyamide resin / conductive material was 80/20. Conductive resin particles c (average particle size 20 μm) were obtained by this method.

・ Conductive resin particles d
Conductive resin except that nickel-coated carbon fiber (Ni-coated carbon fiber chop: C903 (manufactured by Toho Tenax Co., Ltd.)) was used as the conductive material [D] and the mass ratio of polyamide resin / conductive material was 50/50. Conductive resin particles d (average particle size 20 μm) were obtained in the same manner as for particles a.

・ Conductive resin particles e
Conductive resin particles a () except that metal particles (silver powder: Ag-2-11 (manufactured by DOWA Electronics)) are used as the conductive material [D] and the mass ratio of polyamide resin / conductive material is 70/30. Conductive resin particles e were obtained in the same manner as in the case of an average particle diameter of 20 μm.

・ Conductive resin particles f
Polyethersulfone resin (5003P (manufactured by Sumitomo Chemical Co., Ltd.)), which is an epoxy resin-soluble thermoplastic resin, is used as the dispersion resin [E], and carbon black (Ketjen black EC300J (manufactured by Lion)) is used as the conductive material [D]. Using.

  After the polyethersulfone resin / conductive material was uniformly mixed at a mass ratio of 90/10 using a tumbler, the cylinder temperature was set to 330 with a 25 mmφ vented co-rotating twin-screw kneading extruder (HK-25D). Pelletization was performed while degassing at a vacuum degree of 10 mm Hg. Then, it grind | pulverized and obtained the conductive resin particle f (average particle diameter of 20 micrometers).

・ Conductive resin particles g
Polyimide resin (Aurum PD450M (Mitsui Chemicals)), which is a bismaleimide resin-insoluble thermoplastic resin, is used as the dispersion resin [E], and carbon black (Ketjen Black EC300J (Lion)) is used as the conductive material [D]. It was.

  Polyimide resin / conductive material was uniformly mixed using a tumbler at a mass ratio of 90/10, and then the cylinder temperature was 380 ° C. with a 25 mm φ vented co-rotating twin-screw kneading extruder (HK-25D). Pelletization was performed while degassing at a vacuum degree of 10 mm H g. Then, it grind | pulverized and obtained the conductive resin particle g (average particle diameter of 20 micrometers).

[Conductive material]
The following conductive substances were used as conductive materials other than the conductive resin particles.

・ Conductive material A
Conductive carbon black with a particle size of 39.5 nm (catalog value) [Ketjen Black EC300J (trade name) manufactured by Lion Corporation]
-Conductive material B Pitch-based carbon fiber milled fiber dielead with an average fiber length of 200 μm (catalog value): K223HM (Mitsubishi Resin Co., Ltd.)
[Thermoplastic resin]
・ Thermoplastic resin A
Polyethersulfone having an average particle size of 20 μm [PES-5003P (trade name) manufactured by Sumitomo Chemical Co., Ltd.] (a thermoplastic resin soluble in an epoxy resin)
・ Thermoplastic resin B
Grillamide with an average particle size of 20 μm [TR-55 (trade name) manufactured by M Chemie Japan Co., Ltd.] (a thermoplastic resin insoluble in epoxy resin)
・ Thermoplastic resin C
Polyetherimide with an average particle size of 15 μm [Utem1000-1000 (trade name) manufactured by SABIC Innovative Plastics] (a thermoplastic resin soluble in bismaleimide resin)
・ Thermoplastic resin D
Polyimide with an average particle size of 20 μm [AURAM PD450M (trade name) manufactured by Mitsui Chemicals, Inc.] (a thermoplastic resin insoluble in bismaleimide resin)
(Other)
Additive HYPRO ATBN 1300X16 (manufactured by Emerald Performance Materials) [Measurement method]
(1) Average particle size The average particle size was measured by measuring the particle size distribution using a laser diffraction / scattering particle size analyzer (Microtrack method) MT3300 manufactured by Nikkiso Co., Ltd. ₅₀ ) was defined as the average particle size.

(2) Viscosity evaluation of resin composition Rheometer ARES-RDA manufactured by Rheometrics was used. The thickness of the epoxy resin composition between parallel plates having a diameter of 25 mm was set to 0.5 mm. Viscosity was measured up to 180 ° C. at a temperature rising rate of 2 ° C./min under the condition of an angular velocity of 10 radians / second. The viscosity at 80 ° C. was measured using the obtained temperature-viscosity curve.

(3) Moldability evaluation Samples for moldability evaluation of each prepreg were produced using an autoclave molding method. That is, the prepreg was cut and laminated to obtain a laminated body having a laminated structure [+ 45/0 / −45 / 90] _2S . This laminate was molded by a normal autoclave molding method. The molding conditions were a pressure of 0.49 MPa, a temperature of 180 ° C. and 120 minutes. The presence or absence of voids in the molded product thus obtained was evaluated at a scan pitch of 0.5 mm using an ultrasonic flaw detector (SDS-Win 3600 (manufactured by Krautkramaer)) and an ultrasonic probe (5 MHz). Indicates that there is no defective molding portion, and that there is a defective molding portion is ×.

(4) Z direction volume resistivity measurement In the present invention, the conductivity of the composite material was evaluated using the volume resistivity in the Z direction (thickness direction). Volume resistivity is the specific resistance of a given material. The unit of measurement of the conductivity of the three-dimensional material is ohm-cm (Ω · cm). The volume resistivity ρ in the Z direction of the material is usually defined by the following equation.

ρ = RA / L
R: Electrical resistance of the test piece (measured with a digital ohmmeter)
L: Test piece thickness (m)
A: Cross section of test piece (m ² )
In the present invention, the volume resistance is measured only in the Z direction (in the thickness direction of the composite material). Since thickness is always taken into account in the calculation, in all cases this value is the “volume” resistivity.

Preparation method of sample for measuring Z direction volume resistivity The prepreg was cut and laminated to obtain a laminated body of a laminated structure [+ 45/0 / −45 / 90] _2S . Using a vacuum autoclave molding method, molding was performed at 180 ° C. for 120 minutes under a pressure of 0.49 MPa. The obtained molded product was cut into a dimension of width 40 mm × length 40 mm, and the surface of the molded product was polished using sandpaper until the carbon fibers were exposed. Finally, surface finishing was carried out using No. 2000 sandpaper to obtain a test piece. The obtained test piece was sandwiched between two electrodes plated with gold 50 mm wide × 50 mm long.

  With a load of 0.06 MPa applied between both electrodes, the resistance value of the test piece in the Z direction was measured with a digital ohm meter (AX-114N, manufactured by ADEX), and the volume resistivity was obtained from the above equation. The resistance values of ten test pieces were measured, the volume resistivity was calculated, and the average value was used for evaluation.

Example 1
In a kneading apparatus, 50 parts by mass of “Araldite (registered trademark)” MY0600 which is an epoxy resin and 50 parts by mass of MY721 (both manufactured by Huntsman) are combined with 10 parts by mass of a polyethersulfone 5003P (heat The plastic resin A) was added and stirred at 120 ° C for 30 minutes with a stirrer to completely dissolve it, and then the resin temperature was cooled to 80 ° C or lower. Thereafter, 30 parts by mass of conductive resin particles a and 20 parts by mass of 5003P particles (thermoplastic resin A) are kneaded, and 4,4′-diaminodiphenylsulfone (4,4′-DDS) as a curing agent is further mixed. A thermosetting epoxy resin composition [B] was prepared by kneading 45 parts by mass. The resin viscosity of the obtained resin composition was measured.

The prepared thermosetting resin composition was applied onto release paper using a film coater to prepare ^two 51 g / m ² resin films. Next, the two produced resin films were stacked on both sides of a carbon fiber sheet in which carbon fiber bundles were arranged in one direction. By heating and pressurizing, the carbon fiber sheet was impregnated with the resin, and a unidirectional prepreg having a carbon fiber basis weight of 190 g / m ² and a matrix resin mass fraction of 35.0% was produced.

  Using the produced unidirectional prepreg, the moldability and the conductivity of the composite material were evaluated. The obtained results are shown in Table 1.

  ○ indicates that the moldability is good, and x indicates that the moldability is poor.

(Examples 2 to 7)
Except that the blending amount (part by mass) of the conductive material A or the conductive material B, which is a conductive substance other than the thermoplastic resin, the conductive resin particles, or the conductive resin particles, is changed as shown in Table 1, Example 1 and A prepreg was produced in the same manner. Using the produced thermosetting resin composition and the unidirectional prepreg, the resin viscosity, the moldability, and the conductivity of the composite material were evaluated.

(Comparative Example 1)
In a kneading apparatus, 50 parts by mass of “Araldite (registered trademark)” MY0600 and 50 parts by mass of MY721 were agitated with a stirrer at 120 ° C. for 30 minutes to completely dissolve 10 parts by mass of polyethersulfone resin 5003P. Then, the resin temperature was cooled to 80 ° C or lower. Thereafter, 27 parts by mass of polyamide resin grillamide TR-55 particles (thermoplastic resin B) and 20 parts by mass of polyethersulfone resin 5003P (thermoplastic resin A) are kneaded, and 4,4′-diamino which is a curing agent. 45 parts by mass of diphenylsulfone was kneaded to prepare a thermosetting epoxy resin composition [B].

(Comparative Examples 2-3)
The same as Comparative Example 1 except that conductive material A or conductive material B, which is a conductive substance other than conductive resin particles, was used and the blending amount (part by mass) of the thermoplastic resin was changed as shown in Table 1. A prepreg was prepared. Using the produced thermosetting resin composition and the unidirectional prepreg, the resin viscosity, moldability and conductivity were measured. Furthermore, the moldability was evaluated.

  The moldability of the test pieces obtained in Examples 1 to 7 was good and the conductivity was very good. In Example 2 in which a conductive material (conductive material A) other than the conductive resin particles was added, the resin viscosity was improved compared to Example 1 due to the presence of the conductive material A, but this does not interfere with use. A composite material having excellent conductivity was obtained.

  In Example 3 in which the addition amount of the conductive resin particles a was increased, a composite material having conductivity even better than that in Example 1 was obtained.

  In Example 4 in which the conductive resin particles were changed to the conductive resin particles b with a large amount of conductive material added, a composite material having higher conductivity than that obtained in Example 1 was obtained.

  In Example 5 using the conductive resin particles f using a soluble thermoplastic resin as the dispersion resin [E], the conductive material [D] is dispersed in the composite material and has excellent conductivity, and the resistivity is measured. In addition, there was obtained a composite material having a small variation in resistance value for each test piece and having uniform conductivity.

  In Example 6 in which conductive resin particles f were further added in addition to conductive resin particles a, conductive material [D] in conductive resin particles f was dispersed in the composite material, and the resulting composite material was a conductive resin. Although it is not as much as Example 3 in which the same amount of conductive material is added using only particles a, it is a composite material with excellent electrical conductivity, and when the resistivity is measured, the variation in resistance value between test pieces is implemented. A composite material smaller than Example 3 and having uniform conductivity was obtained.

  In Example 7, by using the conductive resin particles a, the conductive resin particles f, and the conductive material A in combination, a large amount of a conductive material of 5.1 wt% with respect to the total amount of the epoxy resin composition can be added. A composite material having excellent conductivity was obtained.

  On the other hand, the composite material obtained in Comparative Example 1 has low conductivity because there is no conductive material in the matrix resin. Although the prepreg obtained in Comparative Example 2 had good moldability, the conductive material was dispersed throughout the matrix resin, so that the formation of a conductive path was insufficient, and the conductivity of the molded product was low. In Comparative Example 3, since the conductive material was directly kneaded with the resin composition, the resin viscosity was remarkably increased, the moldability was poor, and the appropriate conductivity could not be evaluated.

(Examples 8 to 10)
Except for changing the blending amount (parts by mass) of the conductive material A or conductive material B, which is a conductive material other than the curing agent, thermoplastic resin, conductive resin particles, and conductive resin particles, as shown in Table 2. A prepreg was produced in the same manner as in Example 1. Using the produced thermosetting resin composition and the unidirectional prepreg, the resin viscosity, the moldability, and the conductivity of the composite material were evaluated. The obtained results are shown in Table 1.

  The moldability of the prepregs obtained in Examples 8 to 10 was good, and the conductivity of the obtained composite material was very good. Thus, even when the types and blending ratios of the conductive material [D] and the dispersion resin [E] constituting the conductive resin particles [C] were changed, the same effects as in Example 1 were obtained.

(Example 11)
The alkenylphenol (Matrimid 5292B) and the resin-soluble thermoplastic resin (ULTEM1000-1000 particles) were stirred at 120 ° C. for 30 minutes using a stirrer at a ratio (parts by mass) shown in Table 3 and completely dissolved. Then, it is cooled to 60 ° C., a bismaleimide compound (Matrimid 5292A), an additive (HYPRO ATBN 1300X16), a resin-insoluble thermoplastic resin (AURUM PD450M), and conductive resin particles g are added, mixed and stirred for 30 minutes, A curable bismaleimide resin composition was prepared.

The prepared thermosetting resin composition was applied onto release paper using a film coater to prepare ^two 51 g / m ² resin films. Next, on the carbon fiber sheet in which the carbon fiber bundles were arranged in one direction, the two produced resin films were stacked on both sides of the carbon fiber. By heating and pressurizing, the carbon fiber sheet was impregnated with the resin, and a unidirectional prepreg having a carbon fiber basis weight of 190 g / m ² and a matrix resin mass fraction of 35.0% was produced.

  Using the produced thermosetting resin composition and the unidirectional prepreg, the resin viscosity, the moldability, and the conductivity of the composite material were evaluated. The obtained results are shown in Table 3.

(Comparative Example 4)
A prepreg was prepared in the same manner as in Example 11 except that the conductive material A was added instead of the conductive fine particles g and the blending amount of the thermoplastic resin was changed as shown in Table 3. Using the produced thermosetting resin composition and the unidirectional prepreg, the resin viscosity, the moldability, and the conductivity of the composite material were evaluated.

  The moldability of the test pieces obtained in Example 11 and Comparative Example 4 was good. The volume resistivity of the test piece is higher in conductivity obtained in Example 11, and the test piece obtained in Comparative Example 4 has a conductive path formed because the conductive material is dispersed throughout the matrix resin. Due to insufficiency, the conductivity of the molding was low.

A Reinforcing fiber base material B Resin composition C Conductive resin particles D Conductive material E Dispersion resin b Matrix resin

Claims (9)

Reinforcing fiber base and [A], a prepreg Do that because the resin composition [B] contained between the fiber base of the reinforcing fiber base [A],
The resin composition [B] is a matrix resin [b], the a matrix resin [b] an average particle diameter of 0.01~100μm conductive resin particles by dispersing a laser diffraction method [C], from Become
The conductive resin particles [C] is a conductive material [D], wherein the matrix seen containing a different dispersion resin [E] and the resin [b], the conductive material in the dispersed resin [E] [D] A prepreg characterized by being dispersed particles .   The prepreg according to claim 1, wherein the matrix resin [b] is a thermosetting resin. The prepreg according to claim 1 or 2 wherein the partial dispersion resin [E] is a thermoplastic resin. The matrix resin [b] is made of an epoxy resin or a bismaleimide resin,
The partial dispersion resin [E] is a polyamide, polyacetal, polyphenylene oxide, polyphenylene sulfide, polyester, polyamide, polyimide, polyether ketone, polyether ether ketone, polyethylene naphthalate, polyether nitrile, from the group consisting of polybenzimidazole The prepreg according to any one of claims 1 to 3, wherein the prepreg is one or more selected resins . The matrix resin [b] is made of an epoxy resin or a bismaleimide resin,
Before SL min dispersed resin [E] is a resin that dissolves the matrix resin [b] 80 wt% or more at a temperature of 190 ° C., prepreg according to any one of claims 1 to 3. The partial dispersion resin [E] is a polyamide, polyacetal, polyphenylene oxide, polyphenylene sulfide, polyester, polyamide, polyimide, polyether ketone, polyether ether ketone, polyethylene naphthalate, polyether nitrile, from the group consisting of polybenzimidazole One or more selected resins;
The prepreg according to any one of claims 1 to 3, wherein the prepreg is a mixture with a resin that dissolves in an amount of 80 mass% or more in the matrix resin [b] under a temperature condition of 190 ° C.   The prepreg according to any one of claims 1 to 6, wherein the shape of the conductive material [D] is fibrous or particulate.   The conductive material [D] is carbon particles, metal particles, particles in which inorganic material cores are coated with a conductive material, particles in which organic material cores are coated with a conductive material, carbon fibers, metal fibers, and inorganic materials. The prepreg according to any one of claims 1 to 7, wherein the core is at least one selected from the group consisting of a fiber coated with a conductive substance and a core of an organic material coated with a conductive substance. .   A method for producing a carbon fiber reinforced composite material, comprising the steps of laminating the prepreg according to claim 1, pressurizing and heating to mold the resin composition.

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