JP5369655B2 - Polyamide fine particles, prepreg and carbon fiber reinforced composite materials - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyamide fine particle for a carbon fiber-reinforced composite material satisfying CAI (compression strength after impact) and HW ILSS (interlaminar shear strength at high temperature and high moisture), the prepreg and a carbon fiber-reinforced composite material. <P>SOLUTION: The polyamide fine particles, of which the median diameter is 150 &mu;m or smaller, formed by containing a polyamide having at least 4,4'-diaminodicyclohexylmethane and/or its derivative and an aliphatic carboxylic acid as essential constituents, a thermosetting resin such as an epoxy resin, and an aliphatic amine, an aromatic amine, a polyamideamine, a carboxylic acid anhydride, a Lews acid complex, a curing agent of a basic curing catalyst or the like; the prepreg containing the polyamide fine particles and a matrix resin, and carbon fibers; and the carbon fiber-reinforced composite material obtained by curing the prepreg; are provided. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a carbon fiber reinforced composite material excellent in polyamide fine particles and excellent mechanical properties, in particular, a compression strength after impact necessary for aircraft structural materials and an interlaminar shear strength at high temperature and high humidity.

  Carbon fiber reinforced composite materials (hereinafter sometimes abbreviated as CFRP) containing carbon fibers and matrix resins are excellent in specific strength, specific rigidity, heat resistance and environmental resistance. At first, it is widely used. In recent years, especially in the aircraft field, demand for low fuel consumption aircraft has increased due to the recent high fuel consumption, and because of its excellent specific strength and specific rigidity, there is an increasing need for improved CFRP performance that can reduce the weight of the aircraft. Yes.

  Among the mechanical properties required for aircraft structural materials, compressive strength after impact (hereinafter may be abbreviated as CAI) and interlaminar shear strength at high temperature and high humidity (hereinafter also abbreviated as HW ILSS) are the most important. Has been. For this reason, many techniques for improving these mechanical properties are disclosed. For example, as a method for improving CAI, Patent Document 1 arranges thermoplastic resin particles between layers to improve CAI. In Patent Documents 2 and 3, CAI and mechanical properties at high temperature and high humidity are improved by modifying the matrix resin. However, the CFRP's CAI and mechanical properties at high temperature and high humidity were still not sufficient.

Thus, there has been no means for satisfying the CAI of CFRP and the mechanical properties at high temperature and high humidity until now, and a new technology for achieving both mechanical properties has been awaited.
Japanese Patent Laid-Open No. 10-231372 JP-A-8-259713 JP 2001-114915 A

  An object of the present invention is to provide polyamide fine particles for carbon fiber reinforced composite material, prepreg, and carbon fiber reinforced composite material that satisfy CAI and HW ILSS.

The present invention employs the following means in order to solve such problems. That is, a polyamide having at least 4,4′-diaminodicyclohexylmethane and / or a derivative thereof and an aliphatic dicarboxylic acid as essential components, and at least one thermosetting resin selected from the following (A): And the polyamide fine particle characterized by containing at least 1 or more types of hardening | curing agents chosen from (B) shown below, and having a median diameter of 150 micrometers or less.
(Thermosetting resin) Epoxy resin or phenol resin (curing agent) Aromatic amine, aliphatic amine, polyamidoamine, carboxylic anhydride, Lewis acid complex, acid curing catalyst, base curing catalyst.

  According to a preferred aspect of the polyamide fine particle of the present invention, the polyamide fine particle is composed of 4,4′-diamino-3,3′-dimethyldicyclohexylmethane and 1,12-dodecanedicarboxylic acid as essential components. . According to a preferred aspect of the polyamide fine particles of the present invention, any of the above-mentioned polyamides includes a polyamide containing 4,4′-diaminodicyclohexylmethane and / or a derivative thereof, isophthalic acid, 12-aminododecanoic acid as a constituent component. It is the polyamide fine particle as described above. According to a preferred aspect of the polyamide fine particles of the present invention, the polyamide fine particles according to any one of the above, wherein 0.1 to 25 parts by mass of the thermosetting resin is contained with respect to 100 parts by mass of the polyamide. According to a preferred aspect of the polyamide fine particle of the present invention, the polyamide fine particle according to any one of the above, wherein the thermosetting resin is an epoxy resin. According to a preferred aspect of the polyamide fine particle of the present invention, the polyamide fine particle according to any one of the above, wherein the curing agent is at least one selected from an aromatic amine, an aliphatic amine, and a polyamide amine.

  According to a preferred aspect of the polyamide fine particles of the present invention, the polyamide fine particles according to any one of the above, having a micro compressive strength of 20 MPa or less. According to a preferred aspect of the polyamide fine particles of the present invention, the polyamide fine particles according to any one of the above, wherein the glass transition temperature at the time of water absorption is 90 ° C. or higher. Moreover, the prepreg of the present invention comprises the polyamide fine particles described above, a matrix resin, and carbon fibers. A carbon fiber reinforced composite material according to the present invention is a method for producing a carbon fiber reinforced composite material, comprising the polyamide fine particles described above, and including a step of heat-curing the prepreg described above. .

  In the present invention, “fine particles” are particles including not only spherical shapes but also irregular shapes, and the particle size means particles having a median diameter of 150 μm or less. In the present invention, the “carbon fiber reinforced composite material” means a carbon fiber reinforced composite material obtained by curing a prepreg. In the present invention, the “prepreg” means an intermediate material of the carbon reinforced fiber composite material in which a carbon fiber is impregnated with a matrix resin.

  According to the present invention, it is possible to provide a carbon fiber reinforced composite material (CFRP) in which both CAI and HW ILSS are excellent.

  Hereinafter, the polyamide fine particles, the prepreg, and the fiber reinforced composite material of the present invention will be described in detail.

  The polyamide fine particle of the present invention is a polyamide fine particle comprising a polyamide having at least 4,4'-diaminodicyclohexylmethane and / or a derivative thereof and an aliphatic dicarboxylic acid as essential components.

  Specific examples of 4,4′-diaminodicyclohexylmethane and / or its derivatives include 4,4′-diaminodicyclohexylmethane, 4,4′-diamino-3,3′-dimethyldicyclohexylmethane, 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.

  Specific examples of the aliphatic 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 Linear saturated dicarboxylic acids such as maleic acid, chain unsaturated dicarboxylic acids such as maleic acid and fumaric acid, and alicyclic dicarboxylic acids such as cyclopropanedicarboxylic acid. 1,12-dodecanedicarboxylic acid is particularly preferable because of its long alkyl chain and high toughness of the polyamide fine particles.

  Polyamide fine particles containing 4,4′-diaminodicyclohexylmethane and / or a derivative thereof and an aliphatic dicarboxylic acid as essential components are at least one or more of the above 4,4′-diaminodicyclohexylmethane and / or a derivative thereof and the above. Polyamide fine particles having a component derived from at least one of the above aliphatic dicarboxylic acids.

  The amount of the constituent component of the polyamide having 4,4'-diaminodicyclohexylmethane and / or its derivative and aliphatic dicarboxylic acid as essential constituent components is preferably 50 to 100% by mass in the total polyamide in the polyamide fine particles. . It is more preferably 80 to 100% by mass from the viewpoint that the toughness of the polyamide itself can be maximized.

Commercially available polyamides comprising 4,4'-diaminodicyclohexylmethane and / or its derivatives and aliphatic dicarboxylic acid as essential components include 'Grillamide (registered trademark)' TR90 (manufactured by Mzavelke), 'TROGAMID (registered trademark). ) ′ CX7323 (manufactured by Degussa).
The polyamide fine particles of the present invention include 4,4′-diaminodicyclohexylmethane and / or a derivative thereof and an aliphatic dicarboxylic acid as essential components, and 4,4′-diaminodicyclohexylmethane and / or a derivative thereof. Polyamide fine particles containing polyamide having isophthalic acid and 12-aminododecanoic acid as constituent components may also be used.

4, 4'-diaminodicyclohexylmethane and / or its derivatives, 4,4'-diaminodicyclohexylmethane and / or its derivatives in polyamides comprising isophthalic acid and 12-aminododecanoic acid as constituents are 4, 4'- Diaminodicyclohexylmethane, 4,4'-diamino-3,3'-dimethyldicyclohexylmethane, 4,4'-diamino-3,3'-diethyldicyclohexylmethane, 4,4'-diamino-3,3'-dipropyl Examples include dicyclohexylmethane, 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 commercially available polyamides comprising 4,4′-diaminodicyclohexylmethane and / or derivatives thereof, isophthalic acid, and 12-aminododecanoic acid include “Grillamide (registered trademark)” TR55 (manufactured by Mzavelke). It is done.

  Polyamide having 4,4′-diaminodicyclohexylmethane and / or a derivative thereof and an aliphatic dicarboxylic acid as essential components is added to 4,4′-diaminodicyclohexylmethane and / or a derivative thereof, isophthalic acid, 12-aminododecanoic acid. As a commercial product of a polyamide having a component as a component, 'Grillamide (registered trademark)' TR70LX (manufactured by Mzavelke) and the like can be mentioned. Further, the above-mentioned 'Grillamide (registered trademark)' TR90 (manufactured by Mzavelke), 'TROGAMID (registered trademark)' CX7323 (manufactured by Degussa) and 'Grillamide (registered trademark)' TR55 (manufactured by Mzavelke) were used in combination. Also good.

  Furthermore, 'Grillamide (registered trademark)' TR90 (manufactured by Mzavelke), 'TROGAMID (registered trademark)' CX7323 (manufactured by Degussa), 'Grillamide (registered trademark)' TR55 (manufactured by Mzavelke) and the above-mentioned 'Grillamide (registered trademark)' Trademark) 'TR70LX (manufactured by Mzavelke) may be used as a mixture.

  The polyamide fine particles may contain polyamide fine particles containing a thermosetting resin. By containing a thermosetting resin in the polyamide fine particles, heat resistance, elastic modulus, etc. as the polyamide fine particles can be controlled. Specific examples of thermosetting resins include epoxy resins, benzoxazine resins, vinyl ester resins, unsaturated polyester resins, urethane resins, phenol resins, melamine resins, maleimide resins, cyanate ester resins, and urea resins. It is done.

  Among these, epoxy resins are preferably used because of their high heat resistance and adhesiveness. As the epoxy resin, for example, a glycidyl ether type epoxy resin obtained from a compound having a hydroxyl group in the molecule and epichlorohydrin, a glycidylamine type epoxy resin obtained from a compound having an amino group in the molecule and epichlorohydrin, A glycidyl ester type epoxy resin obtained from a compound having a carboxyl group in the molecule and epichlorohydrin, an alicyclic epoxy resin obtained by oxidizing a compound having a double bond in the molecule, or 2 selected from these An epoxy resin or the like in which more than one type of group is mixed in the molecule is used.

  Specific examples of the glycidyl ether type epoxy resin include bisphenol A type epoxy resin obtained by reaction of bisphenol A and epichlorohydrin, bisphenol F type epoxy resin obtained by reaction of bisphenol F and epichlorohydrin, resorcinol and epi Resorcinol type epoxy resin obtained by reaction of chlorohydrin, phenol novolac type epoxy resin obtained by reaction of phenol and epichlorohydrin, other polyethylene glycol type epoxy resin, polypropylene glycol type epoxy resin, naphthalene type epoxy resin, and these These are the positional isomers of these groups, and substituted groups with alkyl groups or halogens.

  Commercially available bisphenol A type epoxy resins include “EPON” (registered trademark) 825, “jER” (registered trademark) 826, “jER” (registered trademark) 827, “jER” (registered trademark) 828 (above, Japan). Epoxy Resin Co., Ltd.), “Epicron” (registered trademark) 850 (Dainippon Ink Chemical Co., Ltd.), “Epototo” (registered trademark) YD-128 (Toto Kasei Co., Ltd.), DER-331 DER-332 (manufactured by Dow Chemical), “Bakelite” (registered trademark) EPR154, “Bakelite” (registered trademark) EPR162, “Bakelite” (registered trademark) EPR172, “Bakelite” (registered trademark) EPR173, and “Bakelite” "(Registered trademark) EPR174 (above, manufactured by Bakerite AG)" .

  Commercially available products of bisphenol F type epoxy resin include “jER” (registered trademark) 806, “jER” (registered trademark) 807, “jER” (registered trademark) 1750 (above, manufactured by Japan Epoxy Resin Co., Ltd.), “ “Epicron” (registered trademark) 830 (manufactured by Dainippon Ink & Chemicals, Inc.), “Epototo” (registered trademark) YD-170, “Epototo” (registered trademark) YD-175 (manufactured by Toto Kasei Co., Ltd.), “ Bakelite "(registered trademark) EPR169 (manufactured by Bakerite AG), GY281, GY282, and GY285 (manufactured by Huntsman Advanced Materials) and the like.

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

  Commercial products of phenol novolac type epoxy resins include “jER” (registered trademark) 152, “jER” (registered trademark) 154 (manufactured by Japan Epoxy Resin Co., Ltd.), “Epicron” (registered trademark) 740 (large) Nippon Ink Chemical Co., Ltd.), EPN179, EPN180 (above, manufactured by Huntsman Advanced Materials) and the like.

  Specific examples of the glycidylamine type epoxy resin include tetraglycidyldiaminodiphenylmethanes, glycidyl compounds of aminophenol, glycidylanilines, and glycidyl compounds of xylenediamine.

  Commercially available tetraglycidyldiaminodiphenylmethanes include “Sumiepoxy” (registered trademark) ELM434 (manufactured by Sumitomo Chemical Co., Ltd.), “Araldite” (registered trademark) MY720, “Araldite” (registered trademark) MY721, “Araldite” ( (Registered trademark) MY9512, “Araldite” (registered trademark) MY9612, “Araldite” (registered trademark) MY9634, “Araldite” (registered trademark) MY9663 (manufactured by Huntsman Advanced Materials), “jER” (registered trademark) 604 (Made by Japan Epoxy Resin Co., Ltd.), “Bakelite” (registered trademark) EPR494, “Bakelite” (registered trademark) EPR495, “Bakelite” (registered trademark) EPR496, and “Bakelite” (registered trademark) EPR497 Or more, manufactured by Bakelite AG, Inc.), and the like.

  Commercially available products of aminophenol glycidyl compounds include “jER” (registered trademark) 630 (manufactured by Japan Epoxy Resin Co., Ltd.), “Araldite” (registered trademark) MY0500, “Araldite” (registered trademark) MY0510 (above Huntsman) Advanced Materials Co., Ltd., “Sumiepoxy” (registered trademark) ELM120, “Sumiepoxy” (registered trademark) ELM100 (manufactured by Sumitomo Chemical Co., Ltd.), and the like.

  Examples of commercially available glycidyl anilines include GAN, GOT (manufactured by Nippon Kayaku Co., Ltd.), “Bakelite” (registered trademark) EPR493 (manufactured by Bakelite AG), and the like. Examples of the glycidyl compound of xylenediamine include TETRAD-X (manufactured by Mitsubishi Gas Chemical Co., Inc.).

  Specific examples of the glycidyl ester type epoxy resin include phthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, isophthalic acid diglycidyl ester, dimer acid diglycidyl ester and various isomers thereof.

  Examples of commercial products of diglycidyl phthalate include “Epomic” (registered trademark) R508 (manufactured by Mitsui Chemicals) and “Denacol” (registered trademark) EX-721 (manufactured by Nagase ChemteX Corporation). It is done.

  Examples of commercially available hexahydrophthalic acid diglycidyl ester include “Epomic” R540 (manufactured by Mitsui Chemicals) and AK-601 (manufactured by Nippon Kayaku Co., Ltd.).

  Examples of commercially available dimer acid diglycidyl esters include “jER” (registered trademark) 871 (manufactured by Japan Epoxy Resin Co., Ltd.) and “Epototo” (registered trademark) YD-171 (manufactured by Toto Kasei Co., Ltd.). It is done.

  Commercially available alicyclic epoxy resins include “Celoxide” (registered trademark) 2021P (manufactured by Daicel Chemical Industries), CY179 (manufactured by Huntsman Advanced Materials), “Celoxide” (registered trademark) 2081 (Daicel). Chemical Industry Co., Ltd.) and “Celoxide” (registered trademark) 3000 (Daicel Chemical Industries, Ltd.). As these epoxy resins, bisphenol A type epoxy resins and the like are preferable from the viewpoint of heat resistance and toughness. The said epoxy resin can be used by 1 type, or 2 or more types.

Further, a curing agent can be used in combination with an epoxy resin. Examples of the curing agent used in combination with the epoxy resin include aromatic amines, aliphatic amines, polyamide amines, carboxylic acid anhydrides and Lewis acid complexes, acid-based curing catalysts, base-based curing catalysts, and the like.
Specific examples of the aromatic amine include diaminodiphenyl sulfone and diaminodiphenylmethane.

  Specific examples of aliphatic amines include diethylenetriamine, triethylenetetramine, dicyandiamide, tetraethylenepentamine, dipropylenediamine, piperidine, N, N-dimethylpiperazine, triethylenediamine, polyamidoamine, octylamine, laurylamine. , Myristylamine, stearylamine, cocoalkylamine, beef tallow alkylamine, oleylamine, cured beef tallow alkylamine, N, N-dimethyllaurylamine, N, N-dimethylmyristylamine and the like. Of these, polyamidoamines and aliphatic amines are preferred from the viewpoint of reactivity and toughness of the resulting polyamide fine particles, and polyamidoamines are particularly preferred.

  Commercially available curing agents combined with epoxy resins include 4,4′-diaminodiphenylsulfone (“SumiCure S” (registered trademark) (manufactured by Sumitomo Chemical Co., Ltd.)), 4,4′-diaminodiphenylmethane (MDA- 220 (manufactured by Mitsui Takeda Chemical Co., Ltd.)), dicyandiamide (DICY7 (manufactured by Japan Epoxy Resin Co., Ltd.)), aromatic polyamine ("Ancamin" (registered trademark) 2049 (manufactured by Air Products Japan Co., Ltd.)), Polyamideamine (“Tomide” (registered trademark) # 296 (manufactured by Fuji Kasei Kogyo Co., Ltd.)).

  These curing agents can be used in combination with an appropriate curing aid in order to increase the curing activity. Preferred examples of the case where a curing aid is combined with an epoxy resin include an example of combining dicyandiamide with a urea derivative such as 3- (3,4-dichlorophenyl) -1,1-dimethylurea (DCMU) as a curing aid, Examples include a combination of a group 3 amine and a boron trifluoride ethylamine complex as a curing aid, and a combination of a carboxylic acid anhydride or a novolak resin with a tertiary amine as a curing aid.

  It is preferable that the compounding quantity of this thermosetting resin is 0.1-25 mass parts with respect to 100 mass parts of polyamides. If it exceeds 25 parts by mass, the inherent toughness of the polyamide may be reduced, and if it is less than 0.1 parts by mass, the adhesion between the polyamide and the thermosetting resin may be inferior. The amount of 0.1 to 12 parts by mass is more preferable because the original toughness of the polyamide and the adhesion between the polyamide and the thermosetting resin can be balanced.

  The use ratio of the curing agent to the thermosetting resin is preferably a stoichiometric ratio to the thermosetting resin from the viewpoint of heat resistance and reactivity. Moreover, when using a hardening adjuvant, it is preferable that it is 0.001 to 1 equivalent with respect to 1 equivalent of functional groups of a thermosetting resin.

  In the present invention, these polyamide fine particles have a median diameter of 150 μm or less, preferably 0.1 to 150 μm. If the particle diameter exceeds 150 μm, the carbon fiber arrangement may be disturbed, or the CFRP thickness obtained by laminating may be increased, and the volume content of the carbon fiber may be relatively lowered, thereby reducing the mechanical properties. If the particle size is less than 0.1 μm, the particles may enter between the fibers of the carbon fiber and are not localized in the interlayer portion, so that the presence effect of the particles cannot be obtained sufficiently and the impact resistance may be lowered. The median diameter is preferably 1 to 70 μm, and more preferably 10 to 50 μm, since it is localized in the interlayer portion and impact resistance is enhanced.

  The particle shape is not particularly limited, but is preferably close to a sphere having a major axis / minor axis of 2.0 or less, more preferably a major axis / minor axis of 1.5 or less.

  The median diameter in the present invention indicates a median diameter measured by a laser diffraction particle size distribution analyzer based on the so-called Mie scattering / diffraction theory. Specifically, when the particle size distribution curve of the particle size and the solid particle amount is obtained, it means a particle size (so-called 50% particle size) at which the integrated solid particle amount is 50% with respect to the total solid particle amount. is there.

  In the present invention, the microcompression strength of the polyamide fine particles is preferably 20 MPa or less. If the range of the minute compressive strength exceeds 20 MPa, the polyamide fine particles are deformed, but peeling occurs at the interface between the carbon fiber and the matrix resin, so that the CAI cannot be sufficiently improved. From the viewpoint that the polyamide fine particles efficiently absorb impact energy, 5 MPa or more and 20 MPa or less are more preferable. In order for the fine compression strength of the polyamide fine particles to be 20 MPa or less, the thermosetting resin is preferably contained in an amount of 25 parts by mass or less with respect to 100 parts by mass of the polyamide, and 15 parts by mass or less is contained. Further preferred.

  The micro compressive strength of the polyamide fine particles in the present invention is 10% strength calculated from a test force displaced by 10% of the particle diameter.

  Furthermore, the glass transition temperature at the time of water absorption of the polyamide fine particles in the present invention is preferably 90 ° C. or higher. The glass transition temperature at the time of water absorption refers to the glass transition temperature of the polyamide fine particles after the polyamide fine particles are immersed in warm water at 70 ° C. for 200 hours. When the temperature is lower than 90 ° C., the CFW HW ILSS cannot be sufficiently improved. 110 degreeC or more is more preferable from the point of maintaining the rigidity of CFRP also at the time of water absorption. In order for the polyamide fine particles to have a glass transition temperature at the time of water absorption of 90 ° C. or higher, it is preferable that 25 parts by mass or less of thermosetting resin is contained with respect to 100 parts by mass of polyamide, and 15 parts by mass or less. More preferably.

The method for producing polyamide fine particles comprising the polyamide of the present invention is not particularly limited. Examples include the following methods.
(1) The polyamide is crystallized by heating and melting and cooling. At this time, the thermosetting resin can also be mixed with the polyamide and added.
(2) Polyamide 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 and added.
(3) Polyamide 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 and added.
(4) Polyamide is dissolved in a solvent, and it is poured into a solvent that does not dissolve polyamide in the form of a mist and precipitated (spray reprecipitation method). At this time, the thermosetting resin can also be dissolved in the same solvent as the polyamide and added.
(5) A polyamide solution obtained by dissolving polyamide in a solvent is added and mixed in a poor solvent of the polyamide and incompatible with the solvent of the polyamide, and stirred strongly to obtain an emulsified and dispersed state. The solvent in the dispersion is removed and the polyamide is taken out. At this time, the thermosetting resin can also be dissolved in the same solvent as the polyamide and added.
(6) The polyamide 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 the solvent, it is collected as polyamide fine particles. At this time, the thermosetting resin can also be dissolved in the same solvent as the polyamide 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, (6) may be mentioned as a method that can be classified as a chemical pulverization method and that polyamide particles can be relatively easily obtained. The solvent used in the method (6) may be any solvent as long as the main component is substantially insoluble or hardly soluble in the dispersion medium. Solvents satisfying these characteristics include hydrocarbons such as pentane, hexane, heptane, benzene, toluene, cyclohexane, petroleum ether, methylene chloride, chloroform, dichloroethane, dichloroethylene, 1,1,1-trichloroethylene, trichloroethylene, tetrachloride. Examples thereof include halogenated hydrocarbons such as carbon, ethers such as diethyl ether, esters such as ethyl acetate, and ketones such as methyl ethyl ketone, and a mixture of two or more may be used.

  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 in the solvent. The solvent to be used is appropriately selected depending on the type of polyamide, and the amount thereof is preferably such that the viscosity of the polyamide solution at the start of emulsification is 0.1 to 800 millipascal seconds, more preferably 10 to 500 millipascal seconds. Furthermore, it is determined to be in the range of 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 limited 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 main solvent. The pressure during emulsification may be normal pressure or increased pressure. Normal pressure is more preferable, and a reaction system having such a pressure has an advantage that a member for constructing it is 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. A nonionic, anionic and cationic surfactant may be used in combination with the above-described emulsifier, if necessary. 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.

  The amount of the emulsifier is preferably 0.01 to 20% by mass in the emulsion before phase inversion, and more preferably 0.1 to 15% by mass because the stability of the emulsion is increased. A solvent-containing polyamide solution having a particle size of 0.1 to 150 μm is obtained by gradually adding a dispersion medium that is insoluble or hardly soluble in the polyamide solution being stirred continuously or intermittently to cause phase inversion emulsification. It is done. The stirring speed at that time is preferably 10 to 1000 rpm, and more preferably 50 to 600 rpm from the viewpoint of uniform particle size.

  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 polyamide fine particles.

  As described above, polyamide fine particles can be easily obtained. In the method (6), a median diameter of 150 μm or less can be easily obtained, and particularly those having a median diameter of 150 μm or less sufficiently exhibit the function as polyamide fine particles in various applications.

  When the polyamide fine particles of the present invention are cured by an external energy such as heat or light, an appropriate amount of an uncured thermosetting resin that forms at least a part of the three-dimensional curing is dissolved in the polyamide solution, and then heated to fine particles. By performing the curing treatment, a cured product can be obtained to obtain polyamide fine particles having improved heat resistance, chemical resistance, water absorption rate and strength.

  In the production of the above-mentioned polyamide fine particles (2) to (6), the polyamide solution is further added to an inorganic substance such as silica, alumina, mica, thermoplastic resin, rubber, pigment, dye, antioxidant, lubricant, antistatic agent and plastic. An agent or the like may be dispersed and dissolved. It is also possible to improve the dispersibility and fluidity by adsorbing or spraying ultrafine particles such as silica and alumina on the surface of the polyamide particles in the emulsion and / or dry state.

  The prepreg of the present invention contains the above-mentioned polyamide fine particles, a matrix resin, and carbon fibers. The matrix resin suitably used in the present invention is a thermosetting resin. Specific examples of thermosetting resins include epoxy resins, benzoxazine resins, vinyl ester resins, unsaturated polyester resins, urethane resins, phenol resins, melamine resins, maleimide resins, cyanate ester resins, and urea resins. It is done. Among these, epoxy resins, benzoxazine resins, vinyl ester resins, unsaturated polyester resins, phenol resins and mixtures of these resins have high mechanical properties and are preferably used. In particular, an epoxy resin is particularly preferably used because it is excellent in mechanical properties, has high affinity with fine particles mainly composed of a thermoplastic resin, and is excellent in adhesion to carbon fibers.

  As the epoxy resin, a compound having a plurality of epoxy groups in the molecule is used. Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol AD type epoxy resin, bisphenol AF type epoxy resin, bisphenol S type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, naphthalene type epoxy resin, and phenol compound. Epoxy resins made from dicyclopentadiene copolymers as raw materials, glycidyl ether type epoxy resins such as biphenyl type epoxy resins and novolac type epoxy resins, glycidyl amine type epoxy resins, and combinations of these resins are preferably used.

  In particular, the epoxy resin selected from bisphenol A, AD, AF, S and F types or a combination thereof is preferably 5 to 50 parts by mass, and the glycidylamine type epoxy resin is preferably 50 to 95 parts by mass. The epoxy resin to be contained (the total amount of both is 100 parts by mass) is excellent in the balance between mechanical properties and handleability, and is particularly preferably used.

  Further, a curing agent can be used in combination with an epoxy resin. Examples of the curing agent used in combination with the epoxy resin include aromatic amines, aliphatic amines, carboxylic anhydrides, imidazole compounds, and Lewis acid complexes. Specific examples of the aromatic amine include diaminodiphenyl sulfone and diaminodiphenylmethane. Specific examples of aliphatic amines include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, dipropylenediamine, piperidine, piperazine, N, N-dimethylpiperazine, triethylenediamine, polyamidoamine, octylamine, laurylamine. , Myristylamine, stearylamine, cocoalkylamine, beef tallow alkylamine, oleylamine, cured beef tallow alkylamine, N, N-dimethyllaurylamine, N, N-dimethylmyristylamine and the like.

  These curing agents can be used in combination with an appropriate curing aid in order to increase the curing activity. Preferred examples of the case where a curing aid is combined with an epoxy resin include an example of combining dicyandiamide with a urea derivative such as 3- (3,4-dichlorophenyl) -1,1-dimethylurea (DCMU) as a curing aid, Examples include a combination of a group 3 amine and a boron trifluoride ethylamine complex as a curing aid, and a combination of a carboxylic acid anhydride or a novolak resin with a tertiary amine as a curing aid.

  The use ratio of the curing agent to the thermosetting resin is preferably a stoichiometric ratio to the thermosetting resin from the viewpoint of heat resistance and reactivity. Moreover, when using a hardening adjuvant, it is preferable that it is 0.001 to 1 equivalent with respect to the functional group of a thermosetting resin.

  In the present invention, the thermoplastic resin is dissolved in the matrix resin before curing, and the thermoplastic resin that forms the sea-island structure in the matrix resin after curing, or the thermoplastic resin is dissolved in the matrix resin before curing, and then the matrix after curing. The matrix resin may contain a thermoplastic resin that is compatible with the resin and does not form a sea-island structure. Such thermoplastic resins include carbon-carbon bonds, amide bonds, imide bonds, ester bonds, ether bonds, carbonate bonds, urethane bonds, urea bonds, thioether bonds, sulfone bonds, imidazole bonds, and carbonyl bonds in the main chain. Those having a bond selected from the group consisting of: In particular, one or more resins selected from the group consisting of polysulfone, polyethersulfone, polyetherimide, and polyimide are preferably used. When the thermoplastic resin is mixed, an appropriate viscoelasticity and mechanical properties can be imparted to the epoxy resin by preferably mixing 1 to 20 parts by mass of the thermoplastic resin with respect to 100 parts by mass of the epoxy resin.

  The carbon fibers used in the present invention are preferably continuous fibers. In the present invention, the continuous fiber is a continuous fiber having a length of 10 mm or more, and does not necessarily need to be a continuous fiber over the entire fiber reinforced layer. If the length of the carbon fiber is too short, it may be difficult to sufficiently exert the strength as the reinforcing fiber when the carbon fiber is processed into a composite material. The shape and arrangement of the carbon fibers are not particularly limited, and may be, for example, a single direction, a random direction, a sheet shape, a mat shape, a woven shape, and a braided shape. In particular, for applications that require high specific strength and high specific modulus, an arrangement in which carbon fiber bundles are aligned in a single direction is the most suitable. Are also suitable for the present invention. In general, the carbon fiber bundle has a total fineness of preferably 100 tex or more and 5000 tex or less, and the number of filaments is preferably 3000 or more and 60000 from the viewpoint of excellent handleability and mechanical properties of the obtained CFRP. What is in the following range is preferably used. The fineness of the carbon fiber bundle can be measured according to JIS R 7605 (1999).

  The CFRP of the present invention is preferably formed by laminating a plurality of layers containing matrix resin, polyamide fine particles, and carbon fibers (hereinafter also referred to as basic CFRP layers). In such CFRP, in the interlayer region located between the basic CFRP layers, polyamide fine particles of 80% by mass or more of the total amount of polyamide fine particles present in the entire carbon fiber reinforced composite material are present. Is preferred. The presence of a certain amount or more of polyamide fine particles in the interlayer region is considered to reduce the stress due to the deformation of the particles against the interlayer shear stress applied at the time of impact application, and improve the compressive strength after impact.

  FIG. 1 shows a model cross-sectional view of a CFRP which is an example of the present invention. In FIG. 1, the basic CFRP layer 1, the basic CFRP layer 2, and the basic CFRP layer 3 are laminated in the CFRP. In FIG. 1, the basic CFRP layer 1 has carbon fibers arranged in a direction perpendicular to the paper surface, the basic CFRP layer 2 has carbon fibers arranged in a 45-degree direction with respect to the paper surface, and the basic CFRP layer 3 has The carbon fibers are arranged in a transverse direction parallel to the paper surface.

  Here, as shown in 4 of FIG. 1, the interlayer region is a contact portion between adjacent basic CFRP layers (for example, in the case of FIG. 1, the basic CFRP layer 1 and the basic CFRP layer 2, or the basic CFRP layer 2). And an area formed in the basic CFRP layer 3), where an average thickness of each layer is t, a thickness of 0.3t, which is 0.15t vertically from the surface where the layers contact each other in the thickness direction, The area that you have. In the figure, a mode in which polyamide fine particles 5 are present in the interlayer region 4 is shown. In order to obtain the effects of the present invention, it is preferable that 80% by mass or more of the polyamide fine particles present in the entire CFRP are present in the interlayer region, and the interlayer region satisfying this condition is preferably present in the CFRP. 30% or more, more preferably 50% or more of the total.

  In the present invention, the amount of polyamide fine particles present in the interlayer region can be determined by the following method. First, CFRP is cut perpendicularly to the laminated surface, and the cross section is enlarged 70 times or more to create a photograph of 200 mm × 200 mm or more. Using this cross-sectional photograph, first, the average layer thickness is obtained. The average thickness of the layers is determined by measuring the thickness of at least two laminated portions on five photos at five arbitrarily selected locations and dividing the value by the number of laminated layers. Next, the cross section of the same CFRP is enlarged by 500 times or more to create a photograph of 200 mm × 200 mm or more. Using this photograph, pay attention to one layer and draw a line almost at the center of the layer. Next, two lines having an interval of 30% of the average thickness of the previously obtained layer and two lines having the average thickness of the layer as an interval are drawn symmetrically with respect to the center line. A portion surrounded by two lines having an interval of 30% of the average thickness of the layers in the photograph is an interlayer region. Then, the area of the polyamide fine particles in the interlayer region and the area of the polyamide fine particles in the portion surrounded by the two lines with the average thickness of the layer as an interval are respectively quantified, and the ratio is taken to the interlayer region. The ratio of the polyamide fine particles present can be calculated. This measurement is performed at five or more points arbitrarily selected between a plurality of layers, and the average ratio is defined as the ratio of polyamide fine particles existing in the interlayer region. The area of the polyamide fine particles can be obtained, for example, by taking a photograph in image processing software such as Photoshop manufactured by Adobe and measuring the portion corresponding to the color of the polyamide fine particles with the area measuring function. In the present invention, the amount of polyamide fine particles present in the interlayer region is defined by mass%, but the mass ratio is the same as the value obtained by multiplying the previous area ratio by specific gravity. It is synonymous with the value of mass ratio. At this time, the average particle diameter of the polyamide fine particles existing in the CFRP can be measured using the above-mentioned cross-sectional photograph. Arbitrary 50 or more of the polyamide fine particles in the electron micrograph are selected, and when they are not true spheres, the particle diameter of the major axis is obtained and the number average diameter is obtained to obtain the particle diameter in CFRP.

  In addition, by using the cross-section cutting sample used when taking this photograph, by performing chemical identification analysis such as a local chemical identification device, for example, a time-of-flight secondary ion mass spectrometer, microscopic IR, Its presence can be determined from a peak derived from polyamide having 4,4′-diaminodicyclohexylmethane and / or a derivative thereof and an aliphatic dicarboxylic acid as essential components.

  Furthermore, in the present invention, the volume content (Vf) of the carbon fiber in CFRP is not particularly limited, but Vf is 30% or more from the viewpoint that the obtained CFRP is excellent in specific strength and specific elastic modulus. It is preferable that it is 80% or less. Vf can be measured according to JIS K 7075 (1991).

  Such carbon fibers can be obtained by subjecting raw material carbon fibers to electrolytic surface treatment under specific conditions. As the raw material carbon fiber, known carbon fibers such as acrylic, pitch and rayon can be applied. Among them, acrylic carbon fibers obtained by firing acrylic fibers are preferable because high-strength carbon fibers are easily obtained. Taking the case of acrylic carbon fiber as an example, the method for producing raw carbon fiber will be described in detail below.

  The acrylic fiber is obtained by spinning a spinning dope containing an acrylic polymer. As the spinning method, wet, dry, and dry-wet can be applied, but wet or dry-wet where high-strength yarn can be easily obtained is preferable. Is preferred. As the spinning dope, a polyacrylonitrile homopolymer or copolymer component solution or suspension can be used. After spinning the spinning solution, coagulation, washing with water, stretching, and application of an oil agent are performed to obtain acrylic fibers. The acrylic fiber is further flameproofed, carbonized, and further graphitized as necessary. Raw material carbon fiber is obtained through a so-called firing step. In order to make the carbon fiber more suitable for use in the present invention, the maximum temperature in an inert atmosphere is 1200 ° C. or higher, preferably 1300 ° C. or higher, more preferably 1400 ° C. or higher as carbonization or graphitization conditions. The upper limit is preferably 2000 ° C. or less from the viewpoint of energy saving. In order to improve the strength and elastic modulus of the carbon fiber, the fineness of the single fiber constituting the fine fiber is preferably made fine. Specifically, the single fiber diameter is 7 μm or less. The thickness is preferably 6 μm or less, more preferably 5.5 μm or less. The lower limit is preferably 3 μm or more from the viewpoint of handleability.

  The raw material carbon fiber thus obtained is subjected to electrolytic surface treatment as follows. As the electrolytic solution used for the electrolytic surface treatment, an acidic aqueous solution or an alkaline aqueous solution is preferably used. The electrolyte used in the acidic aqueous solution is not particularly limited as long as it shows acidity in the aqueous solution, such as inorganic acids such as sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid, boric acid and carbonic acid, acetic acid, butyric acid, oxalic acid, acrylic acid, maleic acid and the like. Examples thereof include organic acids or salts of ammonium sulfate, ammonium hydrogen sulfate and the like. Of these, sulfuric acid and nitric acid exhibiting strong acidity are preferred. The electrolyte used for the alkaline aqueous solution includes hydroxides such as sodium hydroxide, potassium hydroxide and barium hydroxide, inorganic salts such as ammonia, sodium carbonate and sodium hydrogen carbonate, and organic salts such as sodium acetate and sodium benzoate. is there. By performing surface treatment using the above aqueous solution, oxygen-containing functional groups such as hydroxyl groups, carboxyl groups, and carbonyl groups are formed on the surface of the carbon fibers, and the wettability between the carbon fibers and the matrix resin increases as the functional groups increase. And the adhesion is improved.

  The raw material carbon fiber is immersed in a tank filled with the electrolytic solution, and electrolysis is performed by energizing the carbon fiber as an anode. In the electrolytic treatment, the amount of electricity is preferably optimized in accordance with the firing temperature of the raw carbon fibers. The amount of electricity supplied is 10 to 200 C / g, preferably 20 to 180 C / g, more preferably 30 to 160 C / g. When the amount of electricity supplied is less than 10 C / g, sufficient functional groups are not formed on the CF surface and the adhesiveness is lowered. On the other hand, if the amount of energized electricity exceeds 200 C / g, the CF surface is damaged due to the high energization treatment, and the tensile properties are degraded.

  Thus, after performing an electrolytic treatment, it is preferable to wash and dry. Moreover, after drying, a sizing agent is applied as necessary, and a carbon fiber suitable for use in the present invention is obtained. The means for applying the sizing agent is not particularly limited. For example, there are a method of immersing in a sizing agent through a roller, a method of contacting a roller to which the sizing liquid is adhered, and a method of spraying the sizing liquid in a mist form. . Further, either a batch type or a continuous type may be used, but a continuous type that can improve productivity and reduce variation is preferable. At this time, it is preferable to control the concentration of the sizing solution, the drying temperature, the yarn tension, and the like so that the amount of the active component of the sizing agent attached to the carbon fiber is uniformly attached within an appropriate range. Moreover, you may vibrate a carbon fiber with an ultrasonic wave at the time of sizing agent provision.

  The drying temperature and drying time are not particularly limited as long as the solvent can be removed. Examples of the solvent used for the sizing agent include water, methanol, ethanol, dimethylformamide, dimethylacetamide, and acetone. Water is preferable from the viewpoint of easy handling and disaster prevention. Therefore, when a compound insoluble or hardly soluble in water is used as a sizing agent, it is preferable to add an emulsifier, a surfactant or the like to make it water dispersible.

  Next, a method suitable for producing the CFRP of the present invention will be described. The CFRP of the present invention can be obtained by laminating a prepreg obtained by impregnating carbon fibers with the above-described uncured matrix resin and curing the uncured matrix resin. Various methods can be used for manufacturing the prepreg. For example, a method in which carbon fibers are passed through a heated uncured matrix resin, or an uncured matrix resin is applied in the form of a film on the surface of a release paper using a reverse roll coater and sandwiched from one side or both sides of the carbon fiber. Applying various methods, such as a method of impregnation by heating and pressurizing, a method in which an uncured matrix resin is dissolved in a solvent to form a solution, impregnated with the solution through carbon fiber, and then dried to remove the solvent Can do. The polyamide fine particles are distributed in the CFRP interlayer region obtained by laminating and curing the above-mentioned polyamide fine particles in the vicinity of one or both surfaces of the prepreg. As a method for allowing the polyamide fine particles to be present in the vicinity of one or both surfaces of the prepreg, a resin in which a matrix resin and polyamide fine particles are mixed is applied to the surface of a release paper or the like using a reverse roll coater, and the above-mentioned It is inserted into the prepreg from one side or both sides, and heated and pressurized. Alternatively, the aforementioned polyamide fine particles are dispersed in the vicinity of one or both surfaces of the prepreg.

  The CFRP of the present invention can be produced by using a molding method such as a hand layup method, a filament winding method, and a resin transfer molding method, in addition to a method of curing a plurality of prepregs after lamination.

Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited by these examples. Each characteristic value was measured as follows. In the following description, all parts represent parts by mass.
(1) Preparation of polyamide fine particles Polyamide having 4,4′-diamino-3,3′-dimethyldicyclohexylmethane and 1,12-dodecanedicarboxylic acid as essential components and 4,4′-diamino-3,3′- 35 parts by mass of a polyamide mixture (“Grillamide” (registered trademark) -TR70LX, manufactured by Mzavelke) comprising dimethyldicyclohexylmethane, isophthalic acid and 12-aminododecanoic acid, bisphenol A type epoxy resin (manufactured by Toto Kasei Co., Ltd.) "Epototo" (registered trademark) YD-128) 1.1 parts by mass and diaminodiphenylmethane (Mita Takeda Chemical Co., Ltd. MDA-220) 0.4 parts by mass as a curing agent, chloroform 225 parts by mass and methanol 75 parts by mass. It added in the mixed solvent and obtained the uniform solution. Next, while stirring the solution at 450 rpm, 362 parts by mass of an aqueous solution in which 6 wt% of polyvinyl alcohol (manufactured by Kanto Chemical Co., Ltd.) is dissolved is gradually added dropwise to disperse the solution in a dispersion medium to remove the solvent. Thereafter, polyamide fine particles were obtained. The obtained polyamide is designated as polyamide fine particles (1).

  Polyamide having 4,4′-diamino-3,3′-dimethyldicyclohexylmethane and 1,12-dodecanedicarboxylic acid as essential components, 4,4′-diamino-3,3′-dimethyldicyclohexylmethane, isophthalic acid, Polyamide mixture containing 12-aminododecanoic acid as a constituent component ("Mizzeramide" (registered trademark) -TR70LX manufactured by Mzavelke) 35 parts by mass, epoxy resin ("Epototo" (registered trademark) YD-128 manufactured by Toto Kasei Co., Ltd.) ) 1.1 parts by mass and 0.4 parts by mass of polyamidoamine (Fuji Kasei Kogyo "Tomide" (registered trademark) # 296) as a curing agent in a mixed solvent of 225 parts by mass of chloroform and 75 parts by mass of methanol Addition to obtain a homogeneous solution. Next, while stirring the solution at 450 rpm, 360 parts by mass of an aqueous solution in which 6 wt% of polyvinyl alcohol (manufactured by Kanto Chemical Co., Ltd.) is dissolved is gradually added dropwise to disperse the solution in a dispersion medium to remove the solvent. Thereafter, polyamide fine particles were obtained. The obtained polyamide is designated as polyamide fine particles (2).

  Polyamide having 4,4′-diamino-3,3′-dimethyldicyclohexylmethane and 1,12-dodecanedicarboxylic acid as essential components, 4,4′-diamino-3,3′-dimethyldicyclohexylmethane, isophthalic acid, A mixture of polyamides having 12-aminododecanoic acid as a constituent component ("Milamide" (registered trademark) -TR70LX, manufactured by Mzavelke) 35 parts by mass, epoxy resin ("Sumiepoxy" (registered trademark) ELM434, manufactured by Sumitomo Chemical Co., Ltd.), Tetraglycidyldiaminodiphenylmethanes) 1.1 parts by mass and 0.4 parts by mass of diaminodiphenylmethane (MDA-220 manufactured by Mitsui Takeda Chemical Co., Ltd.) as a curing agent were added to a mixed solvent of 225 parts by mass of chloroform and 75 parts by mass of methanol. To obtain a homogeneous solution. Next, while stirring the solution at 450 rpm, 362 parts by mass of an aqueous solution in which 6 wt% of polyvinyl alcohol (manufactured by Kanto Chemical Co., Ltd.) is dissolved is gradually added dropwise to disperse the solution in a dispersion medium to remove the solvent. Thereafter, polyamide fine particles were obtained. The obtained polyamide is designated as polyamide fine particles (3).

  Polyamide having 4,4′-diamino-3,3′-dimethyldicyclohexylmethane and 1,12-dodecanedicarboxylic acid as essential components, 4,4′-diamino-3,3′-dimethyldicyclohexylmethane, isophthalic acid, A mixture of polyamides having 12-aminododecanoic acid as a constituent component ("Milamide" (registered trademark) -TR70LX, manufactured by Mzavelke) 35 parts by mass, epoxy resin ("Sumiepoxy" (registered trademark) ELM434, manufactured by Sumitomo Chemical Co., Ltd.), 2.9 parts by mass of tetraglycidyldiaminodiphenylmethane) and 1.2 parts by mass of diaminodiphenylmethane (MDA-220 made by Mitsui Takeda Chemical Co., Ltd.) as a curing agent were added to a mixed solvent of 225 parts by mass of chloroform and 75 parts by mass of methanol. To obtain a homogeneous solution. Next, while stirring the solution at 450 rpm, 362 parts by mass of an aqueous solution in which 6 wt% of polyvinyl alcohol (manufactured by Kanto Chemical Co., Ltd.) is dissolved is gradually added dropwise to disperse the solution in a dispersion medium to remove the solvent. Thereafter, polyamide fine particles were obtained. The obtained polyamide is designated as polyamide fine particles (4).

  Polyamide (Egza Berke "Grillamide" (registered trademark) -TR90) 22 parts by mass, bisphenol A having 4,4'-diamino-3,3'-dimethyldicyclohexylmethane and 1,12-dodecanedicarboxylic acid as essential components Type epoxy resin (Toto Kasei Co., Ltd. “Epototo” (registered trademark) YD-128) 0.7 parts by mass and a curing agent polyamidoamine (Fuji Kasei Kogyo Co., Ltd. “Tomide” (registered trademark) # 296 ) 0.2 parts by mass was added to a mixed solvent of 225 parts by mass of chloroform and 75 parts by mass of methanol to obtain a uniform solution. Next, while stirring the solution at 450 rpm, 186 parts by mass of an aqueous solution in which 3 wt% of polyvinyl alcohol (manufactured by Kanto Chemical Co., Ltd.) is dissolved is gradually added dropwise to disperse the solution in a dispersion medium to remove the solvent. Thereafter, polyamide fine particles were obtained. The obtained polyamide is designated as polyamide fine particles (5).

  Polyamide (Egza Berke "Grillamide" (registered trademark) -TR90) 22 parts by mass, bisphenol A having 4,4'-diamino-3,3'-dimethyldicyclohexylmethane and 1,12-dodecanedicarboxylic acid as essential components Type epoxy resin (Toto Kasei Co., Ltd. “Epototo” (registered trademark) YD-128) 0.7 parts by mass and a curing agent polyamidoamine (Fuji Kasei Kogyo Co., Ltd. “Tomide” (registered trademark) # 296 ) 0.2 parts by mass was added to a mixed solvent of 225 parts by mass of chloroform and 75 parts by mass of methanol to obtain a uniform solution. Next, while stirring the solution at 450 rpm, 185 parts by mass of an aqueous solution in which 6 wt% of polyvinyl alcohol (manufactured by Kanto Chemical Co., Ltd.) is dissolved is gradually added dropwise to disperse the solution in a dispersion medium to remove the solvent. Thereafter, polyamide fine particles were obtained. The obtained polyamide is designated as polyamide fine particles (6).

  4,4′-diamino-3,3′-dimethyldicyclohexylmethane and 1,12-dodecanedicarboxylic acid as essential constituent polyamides (“Milamide” (registered trademark) -TR90, manufactured by Mzavelke), 11 parts by mass, Polyamide containing 4′-diamino-3,3′-dimethyldicyclohexylmethane and 1,12-dodecanedicarboxylic acid as essential components, 4,4′-diamino-3,3′-dimethyldicyclohexylmethane, isophthalic acid, 12- 11 parts by weight of a polyamide mixture (“Grillamide” (registered trademark) -TR70LX, manufactured by Mzavelke), an epoxy resin (“Epototo” (registered trademark) YD-128, manufactured by Toto Kasei Co., Ltd.) 0 .7 parts by mass and polyamidoamine as a curing agent (manufactured by Fuji Kasei Kogyo Co., Ltd. “ Maido "was obtained (R) # 296) homogeneous solution was added 0.2 part by weight in a mixed solvent of 225 parts by weight of chloroform and methanol 75 parts by mass. Next, while stirring the solution at 450 rpm, 186 parts by mass of an aqueous solution in which 6 wt% of polyvinyl alcohol (manufactured by Kanto Chemical Co., Ltd.) is dissolved is gradually added dropwise to disperse the solution in a dispersion medium to remove the solvent. Thereafter, polyamide fine particles were obtained. The obtained polyamide is designated as polyamide fine particles (7).

  4,4′-diamino-3,3′-dimethyldicyclohexylmethane, isophthalic acid, 36 parts by mass of polyamide (“Grillamide” (registered trademark) -TR55, manufactured by Mzavelke), bisphenol A, comprising 12-aminododecanoic acid Type epoxy resin (“Epototo” (registered trademark) YD-128 manufactured by Tohto Kasei Co., Ltd.) 1.1 parts by mass and polyamidoamine as a curing agent (“Tomide” (registered trademark) # 296 manufactured by Fuji Kasei Kogyo Co., Ltd.) 0.4 parts by mass was added to a mixed solvent of 228 parts by mass of chloroform and 76 parts by mass of methanol to obtain a uniform solution. Next, while stirring the solution at 450 rpm, 360 parts by mass of an aqueous solution in which 6 wt% of polyvinyl alcohol (manufactured by Kanto Chemical Co., Ltd.) is dissolved is gradually added dropwise to disperse the solution in a dispersion medium to remove the solvent. Thereafter, polyamide fine particles were obtained. The obtained polyamide is designated as polyamide fine particles (8).

  As the polyamide fine particles (9), commercially available polyamide fine particles (“SP-500” (registered trademark) manufactured by Toray Industries, Inc.) mainly composed of nylon 12 were used.

  Examples of the polyamide fine particles (10) include polyamides having 4,4′-diamino-3,3′-dimethyldicyclohexylmethane and 1,12-dodecanedicarboxylic acid as essential components (“Grillamide” (registered trademark) manufactured by Mzavelke) TR90) was crushed and used as it was.

(2) Measurement of median diameter of polyamide fine particles The median diameter of polyamide fine particles was measured using a laser particle size distribution meter (SALD-2100: manufactured by Shimadzu Corporation). At the time of measurement, the polyamide fine particles to be measured are dispersed at a concentration of about 0.1% by mass in a 0.5% by mass aqueous solution of “Triton” (registered trademark) X-100 (manufactured by Sigma Aldrich) as a surfactant. Using the dispersion as a measurement sample, the median diameter was measured with the particle size distribution analyzer.

(3) Measurement of micro compression strength of polyamide fine particles Polyamide fine particles were measured with a micro compression tester (MCT-W500: Shimadzu Corporation) with a test force of 9.8 mN, a load speed of 0.0892 mN / sec, and an upper pressure indenter of 50 Φ μm in plane. The particles having a particle diameter of 10 μm were tested one by one. The micro compressive strength in the present invention is a 10% strength calculated from a test force displaced by 10% of the particle diameter, and the 10% strength was obtained by the following equation.
10% strength (MPa) = 2.8 P / πd ²
P: Test force (N)
d: Particle diameter (mm).

(4) Measurement of glass transition temperature after water absorption of polyamide fine particles After the polyamide fine particles were immersed in warm water at 71 ° C. for 2 weeks and sufficiently absorbed, using a differential scanning calorimeter (DSC2910: manufactured by TA Instruments Japan) The glass transition temperature was measured at a midpoint temperature determined based on JIS K7121 (1987) with a nitrogen gas flow rate of 30 ml / min and a temperature increase rate of 10 ° C / min. Thermosetting resin amount (parts by mass) of polyamide fine particles with respect to 100 parts by mass of each polyamide fine particle, addition amount of polyamide fine particles (wt%) with respect to matrix resin, median diameter (μm), tensile yield stress (MPa), and glass transition temperature upon water absorption Table 1 shows (° C).

(5) Preparation of matrix resin In a kneading apparatus, 75 parts of tetraglycidyldiaminodiphenylmethane (TGDDM) (ELM-434 manufactured by Sumitomo Chemical Co., Ltd.), bisphenol A type epoxy resin (Epicoat 825 manufactured by Yuka Shell Co., Ltd.) 50 Part, 25 parts of bisphenol F type epoxy resin (Dainippon Ink Chemical Co., Ltd. "Epicron" (registered trademark) 830) and 15 parts of polyethersulfone (PES) (Sumitomo Chemical Co., Ltd. Sumika Excel PES5003P) After dissolution, 40 parts of 4,4′-diaminodiphenylsulfone (4,4′-DDS) as a curing agent (“Ardur” (registered trademark) 976-1, manufactured by Huntsman Advanced Materials) is kneaded to obtain a resin composition. I adjusted things. This resin composition was used as a primary resin.

  On the other hand, 75 parts of tetraglycidyldiaminodiphenylmethane (TGDDM) (ELM-434 manufactured by Sumitomo Chemical Co., Ltd.) and bisphenol F type epoxy resin (“Epicron” (registered trademark) 830 manufactured by Dainippon Ink Chemical Co., Ltd.) 25 After mixing 15 parts of polyethersulfone (PES) (Sumitomo Chemical Co., Ltd. Sumika Excel PES5003P) with 50 parts, 50 parts of the polyamide fine particles prepared above were kneaded, and 4,4 as a curing agent. 40 parts of '-diaminodiphenylsulfone (4,4'-DDS) (“Ardur” 976-1, manufactured by Huntsman Advanced Materials) was kneaded to prepare a resin composition. This resin composition was used as a secondary resin.

(6) Preparation of prepreg Two sheets of a primary resin coated with a film on release paper so as to have a basis weight of 35 g / m ² were prepared. While the coated surfaces face each other, carbon fibers with 24,000 filaments (Toray Industries, Inc., 'Torayca' (registered trademark) T800G) are aligned in one direction and heated and pressed to impregnate the resin. A primary prepreg having a carbon fiber basis weight of 250 g / m ² and a resin content of 21.9% by mass was obtained. Next, two sheets of a secondary resin coated with a film on release paper so as to have a basis weight of 35 g / m ² were prepared. While making this secondary resin coating film face to face, the first primary prepreg was passed through and heated and pressurized in the same manner as the primary, and the carbon fiber basis weight was 250 g / m ² and the resin content was 35.9% by mass. A secondary prepreg was produced. This secondary prepreg was used as an intermediate material for measuring CFRP CAI and HW ILSS.

(7) Interlaminar shear strength (HW ILSS) measurement of CFRP 12 layers of prepregs constituting the CFRP were laminated in the 0 degree direction, and heat-cured in an autoclave at a temperature of 177 ° C. and a pressure of 0.6 MPa for 2 hours to obtain CFRP. . This CFRP is cut out into a rectangle having a 0 degree direction of 13 mm and a width direction of 6.35 mm in accordance with ASTM D2402-07, and is immersed in warm water at 71 ° C. for 2 weeks in accordance with ASTM D2402-07 to sufficiently absorb water. The interlaminar shear strength was measured under an environment of 82 ° C.

(8) CARP measurement of CFRP The prepreg constituting the CFRP is laminated with a configuration of [45 ° / 0 ° / −45 ° / 90 °] _3s (the symbol s indicates mirror symmetry), and the temperature is 177 in the autoclave. C. and a pressure of 0.6 MPa were heat cured for 2 hours to obtain CFRP. According to JIS K7089 (1996), this CFRP was cut into a rectangle of 152.4 mm in the 0 degree direction and 101.6 mm in the 90 degree direction, and an average impact was given to this center by a drop weight impact of 5.4 kg at a drop height of 571 mm. Post compression strength was determined. Further, the measurement was performed in a room temperature dry state (25 ° C. ± 2 ° C., relative humidity 50%).

(Example 1)
Using the polyamide fine particles (1) produced in (1), a secondary resin was produced by the matrix resin production method of (5). A prepreg was prepared as in (6), and the CAI and HW ILSS of CFRP were determined using this secondary prepreg.

(Example 2)
A secondary prepreg was produced in the same manner as in Example 1 except that the polyamide fine particles (1) were changed to the polyamide fine particles (2), and the CFRP CAI and HW ILSS were obtained using the secondary prepreg.

Example 3
A secondary prepreg was produced in the same manner as in Example 1 except that the polyamide fine particles (1) were changed to the polyamide fine particles (3), and the CFRP CAI and HW ILSS were determined using the secondary prepreg.

Example 4
A secondary prepreg was produced in the same manner as in Example 1 except that the polyamide fine particles (1) were changed to the polyamide fine particles (4), and the CFRP CAI and HW ILSS were determined using the secondary prepreg.

(Example 5)
A secondary prepreg was produced in the same manner as in Example 1 except that the polyamide fine particles (1) were changed to the polyamide fine particles (5), and the CFRP CAI and HW ILSS were determined using the secondary prepreg.

Example 6
A secondary prepreg was produced in the same manner as in Example 1 except that the polyamide fine particles (1) were changed to the polyamide fine particles (6), and the CFRP CAI and HW ILSS were determined using the secondary prepreg.

(Example 7)
A secondary prepreg was produced in the same manner as in Example 1 except that the polyamide fine particles (1) were changed to the polyamide fine particles (7), and the CFRP CAI and HW ILSS were obtained using the secondary prepreg.

(Comparative Example 1)
A secondary prepreg was prepared in the same manner as in Example 1 except that the polyamide fine particles (1) were changed to the polyamide fine particles (8), and the CFRP CAI and HW ILSS were determined using the secondary prepreg.

(Comparative Example 2)
A secondary prepreg was produced in the same manner as in Example 1 except that the polyamide fine particles (1) were changed to the polyamide fine particles (9), and the CFRP CAI and HW ILSS were determined using the secondary prepreg.

(Comparative Example 3)
A secondary prepreg was produced in the same manner as in Example 1 except that the polyamide fine particles (1) were changed to the polyamide fine particles (10). However, it was impossible to produce a prepreg with large particles.

  The configurations of the above examples and comparative examples and the results obtained are summarized in Table 1 below. As can be seen from the results of Examples 1 to 7, it can be seen that the CAI and HW ILSS of CFRP are compatible with those of Comparative Examples 1 to 3. This is because when the fine polyamide particles having the chemical structure defined above are used, CAI and HW ILSS are satisfied, but as in the first and second comparative examples, the fine polyamide particles having a chemical structure other than the chemical structure defined in the present invention are used. However, both characteristics cannot be satisfied. Both characteristics are satisfied if the fine compression strength of the polyamide fine particles is 20 MPa or less and the glass transition temperature at the time of water absorption is 90 ° C. or more with the chemical structure defined in the present invention. In Comparative Example 3, when the median diameter was 200 μm, a film-coated product could not be produced when the prepreg was produced, and evaluation could not be performed.

  The carbon fiber reinforced composite material (CFRP) of the present invention is used for sports equipment such as tennis rackets and golf shafts, outer plate members such as automobile bumpers and doors, and automobiles such as chassis and front side members. It can be applied to structural members and the like.

It is a model sectional view of CFRP which is an example of the present invention.

Explanation of symbols

1 Basic CFRP layer 2 Basic CFRP layer 3 Basic CFRP layer 4 Interlayer region 5 Polyamide fine particles

Claims (11)

A polyamide having at least 4,4′-diaminodicyclohexylmethane and / or a derivative thereof and an aliphatic dicarboxylic acid as essential components, at least one thermosetting resin selected from (A) shown below, and Polyamide fine particles characterized by containing at least one curing agent selected from (B) shown below and having a median diameter of 150 μm or less.
(A) Epoxy resin, phenol resin (B) aromatic amine, aliphatic amine, polyamide amine, carboxylic acid anhydride, Lewis acid complex, acid-based curing catalyst, base-based curing catalyst 2. The polyamide fine particles according to claim 1, wherein the polyamide comprises 4,4′-diamino-3,3′-dimethyldicyclohexylmethane and 1,12-dodecanedicarboxylic acid as essential components. 3. The polyamide fine particles according to claim 1, wherein the polyamide contains polyamide having 4,4′-diaminodicyclohexylmethane and / or a derivative thereof, isophthalic acid, and 12-aminododecanoic acid as constituent components. The polyamide fine particles according to any one of claims 1 to 3, wherein 0.1 to 25 parts by mass of a thermosetting resin is contained with respect to 100 parts by mass of the polyamide. The polyamide fine particles according to any one of claims 1 to 4, wherein the thermosetting resin is an epoxy resin. The polyamide fine particles according to any one of claims 1 to 5, wherein the curing agent is at least one selected from an aromatic amine, an aliphatic amine, and a polyamide amine. The polyamide fine particles according to any one of claims 1 to 6, having a micro compressive strength of 20 MPa or less. The polyamide fine particles according to any one of claims 1 to 7, which have a glass transition temperature of 90 ° C or higher upon water absorption. A prepreg comprising the polyamide fine particles according to any one of claims 1 to 8, a matrix resin, and carbon fibers. A carbon fiber reinforced composite material obtained by curing the prepreg according to claim 9. The carbon fiber reinforced composite material is formed by laminating a matrix resin, the polyamide fine particles according to any one of claims 1 to 7, and a plurality of layers containing carbon fibers, and the polyamide fine particles are 80% by mass of the total amount. The carbon fiber reinforced composite material according to claim 10, wherein the above is present in the interlayer region.

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