JP2011162619A - Epoxy resin composition, prepreg and fiber reinforced composite material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an epoxy resin composition that can give a prepreg and a carbon fiber reinforced composite material having excellent shock resistance and tensile strength suitable for airplane members or wind wheel blades. <P>SOLUTION: The epoxy resin composition comprises: [A] an epoxy resin having two or more functional groups and having a glycidyl ether group at a meta position; [B] an epoxy resin having two or more functional groups except for [A]; [C] resin particles insoluble with an epoxy resin and having a structure expressed by general formula (1) (where R<SB>1</SB>and R<SB>2</SB>each represent an alkyl group having 1 to 8 carbon atoms or a halogen element, and they may be identical or different from each other, and R<SB>3</SB>represents a methylene group having 1 to 20 carbon atoms); [D] a thermoplastic resin soluble with an epoxy resin; and [E] an epoxy resin curing agent. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an epoxy resin composition capable of obtaining a prepreg and a fiber-reinforced composite material having both excellent impact resistance and conductivity, and a prepreg and a fiber-reinforced composite material using the same.

  Carbon fiber reinforced composite materials are useful because they are excellent in specific strength and specific rigidity, such as aircraft structural members, windmill blades, automobile outer plates, and computer applications such as IC trays and notebook PC housings. The demand is increasing year by year.

  Carbon fiber reinforced composite material is a heterogeneous material formed by molding a prepreg composed of carbon fibers, which are reinforcing fibers, and a matrix resin as essential components. Therefore, the physical properties of the reinforcing fibers in the alignment direction and the physical properties in other directions There is a big difference. For example, the impact resistance indicated by the resistance to falling weight impact is governed by the delamination strength determined by the interlaminar plate edge delamination strength, etc., so drastic improvement only by improving the strength of the reinforcing fiber It is known that it does not lead to In particular, a carbon fiber reinforced composite material using a thermosetting resin as a matrix resin reflects the low toughness of the matrix resin, and has a property of being easily broken by stress from other than the direction in which the reinforcing fibers are arranged. For this reason, various techniques have been proposed for the purpose of improving the physical properties of composite materials that can cope with stresses from other than the direction in which the reinforcing fibers are arranged, in addition to improving tensile strength and compressive strength in the fiber direction.

  As one of the techniques for improving toughness, a prepreg in which resin fine particles are dispersed on the surface has been proposed. Specifically, it is a technique for imparting high toughness and good heat resistance to a carbon fiber reinforced composite material by dispersing resin fine particles made of a thermoplastic resin such as nylon on the surface of a prepreg (see Patent Document 1). Separately, there has been proposed a technique for expressing a high degree of toughness in a composite material by combining a matrix resin whose toughness has been improved by adding a polysulfone oligomer and fine particles made of a thermosetting resin (see Patent Document 2).

  In the carbon fiber reinforced composite material, the tensile strength is an important physical property for use in, for example, aircraft structural members, windmill blades, and automobile outer plates. The demand for the tensile strength is increasing year by year in order to further reduce the weight. It is also known that even if the strength and elongation of the carbon fiber are increased, the tensile strength of the carbon fiber reinforced composite material is not sufficiently exhibited unless the performance of the matrix resin is accompanied.

  On the other hand, a method has been proposed that combines tensile strength and toughness by combining an epoxy resin having a specific skeleton and resin fine particles that are insoluble in the epoxy resin (Patent Document 3). The above method is not always sufficient when considering the demands for the improvement of the structure and the high toughness.

US Pat. No. 5,028,478 JP-A-3-26750 International Publication No. 2008/40963 Pamphlet

  Accordingly, an object of the present invention is to provide an epoxy resin composition from which a prepreg and a fiber reinforced composite material having excellent impact resistance and tensile strength are obtained, and a prepreg and a fiber reinforced composite material using the same. .

As a result of intensive studies to achieve the above object, the present inventors have found a resin composition having higher tensile strength and higher toughness than conventional ones. That is, the present invention is an epoxy resin composition comprising the following [A] to [E].
[A] Bifunctional or higher epoxy resin having a glycidyl ether group at the meta position [B] Bifunctional or higher epoxy resin other than [A] [C] Insoluble in epoxy resin having a structure represented by the general formula (1) Particles

(Wherein R ₁ and R ₂ represent an alkyl group having 1 to 8 carbon atoms and a halogen element, and may be the same or different. R ₃ represents a methylene group having 1 to 20 carbon atoms) .
[D] Thermoplastic resin soluble in epoxy resin [E] Epoxy resin curing agent.

  According to the present invention, it is possible to obtain an epoxy resin composition excellent in impact resistance and processability when obtaining a prepreg, and by combining this epoxy resin composition and reinforcing fibers such as carbon fibers. A fiber-reinforced composite material having excellent tensile strength and impact resistance can be obtained.

  Hereinafter, the epoxy resin composition, prepreg and fiber-reinforced composite material of the present invention will be described in detail.

  Component [A] of the present invention is a bifunctional or higher functional epoxy resin having a glycidyl ether group at the meta position. When this component [A] is used as a fiber-reinforced composite material using the epoxy resin composition of the present invention and a reinforcing fiber such as carbon fiber, a high tensile strength can be obtained. The epoxy resin referred to in the present invention refers to one having one or more glycidyl groups in the molecule.

  The bifunctional epoxy resin means one having two epoxy groups in the molecule, and the trifunctional epoxy resin means one having three epoxy groups in the molecule. Thus, when the number of epoxy groups (glycidyl groups) in the molecule is N, the epoxy resin is called an N-functional epoxy resin.

  In the present invention, an epoxy resin having a glycidyl ether group at the meta position means that any one of the carbons on the benzene ring to which the glycidyl ether group or the glycidyl amino group is linked is the first position. The glycidyl ether group is connected.

  Specifically, a resorcinol type epoxy resin having a glycidyl ether group at both the 1,3 positions, a 1,3,5-trihydroxybenzene triglycidylated epoxy resin having a glycidyl ether group at the 1,3,5 positions, An N, O-bisglycidylated m-aminophenol type epoxy resin having a glycidylamino group at the 1-position and a glycidyl ether group at the 3-position (referred to as “m-aminophenol-type epoxy resin”) can be mentioned. Moreover, these epoxy resins may have a substituent such as an alkyl group having 4 or less carbon atoms or a halogen element in addition to the 1st and 3rd positions. An epoxy resin having an alkyl group often provides advantages in the manufacturing process of a carbon fiber reinforced composite material, such as a decrease in the overall viscosity. Examples of such epoxy resins include 4-amino-m-cresol and 6-amino-m-cresol N, N, O-triglycidylate (hereinafter, m-aminocresol type epoxy resin). .

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

  Commercially available m-aminophenol type epoxy resins include “Sumiepoxy (registered trademark)” ELM-120 (manufactured by Sumitomo Chemical Co., Ltd.), “Araldite (registered trademark)” MY0600, Araldite MY0610 (above, Huntsman Advanced) -Materials Co., Ltd. made.

  Examples of the m-aminocresol type epoxy include “Sumiepoxy (registered trademark)” ELM-100 (manufactured by Sumitomo Chemical Co., Ltd.).

  The amount of component [A] is preferably 40 parts by mass or more and 90 parts by mass or less in a total of 100 parts by mass of component [A] and component [B]. When the component [A] is less than 40 parts by mass, the tensile strength of the fiber-reinforced composite material that is the effect of the component [A] may not be sufficiently exhibited, and the component [A] is greater than 90 parts by mass. In some cases, the amount of heat generated during curing increases, and heat control such as a difference in temperature between inside and outside of a large structure such as an aircraft wing or a windmill may be difficult to control.

  Component [B] of the present invention is a bifunctional or higher functional epoxy resin other than component [A], and is an essential component for improving processability and heat resistance. In addition, component [B] may contain 2 or more types of epoxy resins other than component [A].

  The component [B] of the present invention preferably has an aromatic ring in the main chain or side chain from the viewpoint of improving heat resistance. Moreover, it is preferable that it is liquid at room temperature from a viewpoint of the process property at the time of carrying out the prepreg formation of the epoxy resin composition of this invention. The term “liquid at room temperature” as used herein refers to a material having a melting point or glass transition temperature obtained based on JIS K7121 (1987) of less than 25 ° C. and exhibiting fluidity at room temperature.

  Such epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, diaminodiphenylmethane type epoxy resin, diaminodiphenyl sulfone type epoxy resin, p-aminophenol type epoxy resin, p-aminocresol type epoxy resin, metaxylylenediamine type epoxy resin, 1,3-bis (aminomethyl) -cyclohexane type epoxy resin, isocyanurate type epoxy resin and hydantoin type epoxy resin, etc. Is mentioned.

  Commercially available bisphenol A type epoxy resins include “EPON (registered trademark)” 825 (manufactured by Japan Epoxy Resin Co., Ltd.), “Epicron (registered trademark)” 850 (manufactured by DIC Corporation), “Epototo ( Registered trademark) "YD-128 (manufactured by Tohto Kasei Co., Ltd.), DER-331, DER-332 (manufactured by Dow Chemical Co., Ltd.), and the like.

  As commercial products of bisphenol F type epoxy resin, “jER (registered trademark)” 806, “jER (registered trademark)” 807 and “jER (registered trademark)” 1750 (above, manufactured by Japan Epoxy Resins Co., Ltd.), “Epiclon (registered trademark)” 830 (manufactured by DIC Corporation), “Epototo (registered trademark)” YD-170 (manufactured by Toto Kasei Corporation), and the like.

  Commercially available diaminodiphenylmethane type epoxy resins include ELM434 (manufactured by Sumitomo Chemical Co., Ltd.), “Araldite (registered trademark)” MY720, “Araldite (registered trademark)” MY721, “Araldite (registered trademark)” MY9512, “Araldite (registered trademark)” MY9663 (manufactured by Huntsman Advanced Materials), “Epototo (registered trademark)” YH-434 (manufactured by Toto Kasei Co., Ltd.), and the like.

  Examples of commercially available metaxylylenediamine type epoxy resins include TETRAD-X (manufactured by Mitsubishi Gas Chemical Co., Inc.).

  Examples of commercially available 1,3-bisaminomethylcyclohexane type epoxy resins include TETRAD-C (manufactured by Mitsubishi Gas Chemical Co., Inc.).

  As a commercial item of an isocyanurate type epoxy resin, TEPIC-P (manufactured by Nissan Chemical Industries, Ltd.) can be mentioned.

  As a commercial item of a trishydroxyphenylmethane type epoxy resin, Tactix 742 (manufactured by Huntsman Advanced Materials Co., Ltd.) can be mentioned.

  As a commercial product of a tetraphenylolethane type epoxy resin, “jER (registered trademark)” 1031S (manufactured by Japan Epoxy Resin Co., Ltd.) may be mentioned.

  Commercially available p-aminophenol type epoxy resins include “jER (registered trademark)” 630 (manufactured by Japan Epoxy Resin Co., Ltd.), and “Araldite (registered trademark)” MY0510 (Huntsman Advanced Materials ( Manufactured by the same company).

  TG3DAS (Mitsui Chemicals Fine Co., Ltd.) etc. are mentioned as a commercial item of the tetraglycidyl dimino diphenyl sulfone type epoxy resin.

  Examples of commercial products of glycidyl aniline type epoxy resins include GAN and GOT (manufactured by Nippon Kayaku Co., Ltd.).

  NC-3000 (made by Nippon Kayaku Co., Ltd.) etc. is mentioned as a commercial item of a biphenyl type epoxy resin.

  Examples of commercially available dicyclopentadiene type epoxy resins include “Epicron (registered trademark)” HP7200, “Epicron (registered trademark)” HP7200L, “Epicron (registered trademark)” HP7200H (above, manufactured by DIC Corporation), and the like. Can be mentioned.

  Examples of commercially available urethane-modified epoxy resins include AER4152 (manufactured by Asahi Kasei Epoxy Corporation).

  Examples of commercially available phenol novolac epoxy resins include DEN431 and DEN438 (manufactured by Dow Chemical Co., Ltd.) and “jER (registered trademark)” 152 (manufactured by Japan Epoxy Resins Co., Ltd.).

  Examples of commercially available ortho cresol novolac epoxy resins include EOCN-1020 (manufactured by Nippon Kayaku Co., Ltd.) and “Epiclon (registered trademark)” N-660 (manufactured by DIC Corporation).

  A commercial product of hydantoin type epoxy resin includes AY238 (manufactured by Huntsman Advanced Materials Co., Ltd.).

  Component [C] particles are resin particles made of polyamide resin that is insoluble in epoxy resin in the skeleton of the following general formula (1), and are indispensable components for developing the impact resistance and toughness of the composite. is there. Since these resin particles are insoluble in the epoxy resin, they do not dissolve in the epoxy resin even at a high temperature of 180 ° C., which is reached when the epoxy resin composition that is a matrix resin is cured. The shape can be maintained, and high impact resistance and toughness can be expressed.

(Wherein R ₁ and R ₂ represent an alkyl group having 1 to 8 carbon atoms and a halogen element, and may be the same or different. R ₃ represents a methylene group having 1 to 20 carbon atoms) .

  Insoluble means to check by checking whether the viscosity change is small and within ± 10% after adding to the epoxy resin at a temperature lower than the Tg of the resin particles and stirring for 1 hour before and after stirring. Can do.

  In the present invention, an epoxy resin mixture obtained by pre-kneading 5 parts by mass of resin particles with respect to 100 parts by mass of “EPON (registered trademark)” 825, which is a bisphenol A type epoxy resin kept at 70 ° C., The solubility shall be judged by the presence or absence of viscosity change by the following method.

  The resin is cast on a parallel plate having a diameter of 40 mm using a dynamic viscoelasticity measuring device ARES (manufactured by TA-Instruments Co., Ltd.), and the resin is 1 at a frequency of 0.5 Hz and a gap of 1 mm at a constant temperature of 80 ° C. The change in time viscosity was measured.

  When the resin particles are dissolved, the viscosity increases after the start of measurement, and when the dissolution is completed, the viscosity increase stops and the behavior that the viscosity becomes constant can be observed. When the resin particles are not dissolved, this viscosity change is within ± 10%, so that the solubility of the resin particles can be determined.

  The polyamide resin, which is the main constituent of the resin particles, is characterized in that it is a polyamide having at least 4,4'-diaminodicyclohexylmethane and / or a derivative thereof and an aliphatic dicarboxylic acid as essential constituents.

  Specific examples of 4,4′-diaminodicyclohexylmethane and / or derivatives thereof 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 since it has a long alkyl chain and increases the toughness of resin particles made of polyamide.

  Resin particles comprising 4,4′-diaminodicyclohexylmethane and / or a derivative thereof and a polyamide having an aliphatic dicarboxylic acid as an essential component are at least 1 from the above 4,4′-diaminodicyclohexylmethane and / or a derivative thereof. Resin particles made of polyamide as a constituent component derived from at least one species and at least one species from 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 50 to 100% by mass in the total polyamide in the resin particles made of polyamide. Preferably there is. It is more preferably 80 to 100% by mass from the viewpoint that the toughness of the polyamide itself can be maximized.

  As a commercial product of polyamide having 4,4′-diaminodicyclohexylmethane and / or a derivative thereof and an aliphatic dicarboxylic acid as essential components, “Grillamide (registered trademark)” TR90 (manufactured by Mzavelke Co., Ltd.), “ TROGAMID (registered trademark) ”CX7233, CX9701, CX9704 (manufactured by Degussa Co., Ltd.).

  Further, the resin particles comprising the polyamide 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 Or the resin particle which consists of a polyamide containing the derivative | guide_body, the isophthalic acid, and the polyamide which uses 12-aminododecanoic acid as a structural component may be sufficient.

  4,4′-diaminodicyclohexylmethane and / or derivatives thereof, 4,4′-diaminodicyclohexylmethane and / or derivatives thereof in polyamides containing isophthalic acid and 12-aminododecanoic acid as constituent components are -Diaminodicyclohexylmethane, 4,4'-diamino-3,3'-dimethyldicyclohexylmethane, 4,4'-diamino-3,3'-diethyldicyclohexylmethane, 4,4'-diamino-3,3'-di Examples include propyldicyclohexylmethane, 4,4′-diamino-3,3′-dichlorodicyclohexylmethane, 4,4′-diamino-3,3′-dibromodicyclohexylmethane. Of these, 4,4'-diaminodicyclohexylmethane and 4,4'-diamino-3,3'-dimethyldicyclohexylmethane are preferred from the viewpoint of heat resistance.

  As a commercial product of polyamide comprising 4,4′-diaminodicyclohexylmethane and / or a derivative thereof, isophthalic acid, and 12-aminododecanoic acid as constituents, “Grillamide (registered trademark)” TR55 (manufactured by Mzavelke Co., Ltd.) Etc.

  Polyamide having 4,4′-diaminodicyclohexylmethane and / or a derivative thereof and an aliphatic dicarboxylic acid as essential components, 4,4′-diaminodicyclohexylmethane and / or a derivative thereof, isophthalic acid, 12-aminododecane Examples of commercially available polyamides containing acid as a constituent component include “Grillamide (registered trademark)” TR70LX (manufactured by Mzavelke Co., Ltd.). In addition, the “Grillamide (registered trademark)” TR90 (manufactured by Mzavelke), “TROGAMID (registered trademark)” CX7323 (manufactured by Degussa) and “Grillamide (registered trademark)” TR55 (Mzabelke) May be used as a mixture.

  Furthermore, “Grillamide (registered trademark)” TR90 (manufactured by Mzavelke), “TROGAMID (registered trademark)” CX7323 (manufactured by Degussa), “Grillamide (registered trademark)” TR55 (Mzabelke) The above-mentioned “Grillamide (registered trademark)” TR70LX (manufactured by Mzavelke Co., Ltd.) may be used in combination.

  Moreover, the resin particle which consists of said polyamide may contain the thermosetting resin in it. By containing a thermosetting resin in the resin particles made of the polyamide, the heat resistance, elastic modulus and the like of the resin particles can be controlled. Specific examples of the thermosetting resin contained in the polyamide resin particles include epoxy resins, benzoxazine resins, vinyl ester resins, unsaturated polyester resins, urethane resins, phenol resins, melamine resins, maleimide resins, and cyanides. Examples include acid ester resins and urea resins.

  The particle diameter of the resin particles is affected by the process of producing the resin composition and the process of producing the fiber reinforced composite material, but the average particle diameter is preferably between 1 and 150 μm, more preferably 1 to The thickness is 100 μm, more preferably 5 to 50 μm, and particularly preferably 5 to 35 μm.

  If the average particle size is less than this range, it is difficult to create resin particles, and the fibers are aligned in the gap between the fibers during the process of manufacturing the fiber reinforced composite material. May disturb the strength of the fiber-reinforced composite material. Further, when the average particle diameter is larger than 150 μm, clogging of filters, slitters, etc. used in the process may occur, which may be a defect of the fiber reinforced composite material.

  The average particle diameter here can be calculated by measuring an arbitrary 100 particle diameters from a scanning electron micrograph and calculating the arithmetic average thereof. In the above photograph, when the shape is not a perfect circle, that is, when it is oval, the maximum diameter of the particle is taken as the particle diameter. In order to accurately measure the particle size, it is measured at a magnification of at least 1000 times, preferably 5000 times or more.

  As the shape of the resin particles, spherical particles are preferable in terms of stable impact resistance and viscosity stability when making fiber reinforced composite materials, but elliptical spherical, flat, rocky, scalloped sugar, amorphous It can be used even in the shape of. The inside of the particles may be hollow or porous.

  Any existing method may be used as a method for producing the resin particles. For example, a method of obtaining fine particles by mechanical pulverization after freezing with liquid nitrogen or the like, a method of spray drying after dissolving raw materials in a solvent, by mechanically kneading a resin component to be granulated and a different resin component Examples thereof include a forced melt kneading emulsification method in which a sea-island structure is formed and then sea components are removed with a solvent, and a method in which raw materials are dissolved in a solvent and then reprecipitated or reaggregated in a poor solvent.

  Further, it is possible to impart a new function by processing the surface of the resin particles.

  For example, the resin particle of this invention can be used as a core material, and the method of attaching another shell layer on the surface etc. is mentioned. At this time, the shell layer to be selected differs depending on the desired function. For example, a conductive metal such as iron, cobalt, copper, silver, gold, platinum, palladium, tin, or nickel is used as the shell layer. By giving, the function of improving the electroconductivity of matrix resin can be provided. When a metal is applied as a shell layer, the thickness of the shell should be sufficient to obtain the characteristics of the desired function, but when the matrix resin is prepared, it is too large compared to the specific gravity of the matrix resin. If the particle size is too small, uniform mixing cannot be achieved. Therefore, the specific gravity of the final particles imparted with the metal to the shell layer is preferably between 0.9 and 2.0.

  The component [D] is a thermoplastic resin that is soluble in the epoxy resin. By blending these, the viscosity of the matrix resin can be adjusted to an appropriate region, and when combined with carbon fiber to form a prepreg, the tackiness and draping properties can be adjusted to a range suitable for the purpose of use. It is also important for improving the impact resistance and interlayer toughness of the epoxy resin. “Soluble” as used herein refers to whether the viscosity change is smaller than −10% or larger than 10% before and after stirring by adding to the epoxy resin at a temperature lower than Tg or melting point and stirring for 1 hour. It can be judged by how.

  Such thermoplastic resins are generally selected from the group consisting of carbon-carbon bonds, amide bonds, imide bonds, ester bonds, ether bonds, carbonate bonds, urethane bonds, thioether bonds, sulfone bonds and carbonyl bonds in the main chain. A thermoplastic resin having a selected bond is preferred, but it may have a partially crosslinked structure.

  Moreover, this thermoplastic resin may have crystallinity or may be amorphous. In particular, polyamide, polycarbonate, polyacetal, polyphenylene oxide, polyphenylene sulfide, polyarylate, polyester, polyamideimide, polyimide, polyetherimide, polyimide with phenyltrimethylindane structure, polysulfone, polyethersulfone, polyetherketone, polyetheretherketone It is preferable that at least one resin selected from the group consisting of aramid, polyether nitrile, and polybenzimidazole is mixed or dissolved in the epoxy resin composition. Polyether sulfone, polyether imide, or polyphenylene ether, which can easily obtain high interlayer toughness when used as a fiber-reinforced composite material, is preferable. Particularly preferred is polyethersulfone.

  When this thermoplastic resin is dissolved in an epoxy resin, the preferred blending amount varies depending on the average molecular weight and molecular weight distribution of the thermoplastic resin and the interaction with the epoxy resin.

  Practically, it is preferable that 1-30 mass% is contained in an epoxy resin composition. For example, the optimum amount of polyethersulfone varies depending on the molecular weight and the type of the terminal functional group, but it is preferably contained in an amount of 5 to 20% by mass in order to adjust the viscosity and develop composite physical properties. In the case where the terminal functional group is a hydroxyl group or an amino group, it is preferable that high composite physical properties are easily developed due to affinity and reactivity with the epoxy resin.

  The component [E] is an epoxy resin curing agent. It is an essential component for reacting with the component [A] and [B] to form a crosslinked structure and to give good heat resistance and high mechanical strength.

  As the epoxy resin curing agent [E], any compound having an active group capable of reacting with an epoxy resin can be used.

  Preferably, a compound having an amino group, an acid anhydride group or an azide is suitable. Examples include dicyandiamide, alicyclic amines, aliphatic amines, aromatic amines, aminobenzoic acid esters, various acid anhydrides, phenol novolac resins, cresol novolac resins, imidazole derivatives, boron trifluoride complexes and boron trichloride. Examples include Lewis acid complexes such as complexes.

  In particular, an aromatic amine curing agent is preferably used in terms of providing an epoxy resin cured product having excellent mechanical properties. Of these, aromatic polyamines having two or more amino groups are preferred from the viewpoint of heat resistance.

  Specific examples of aromatic polyamines include metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, metaxylylenediamine, diphenyl-para-dianiline, various derivatives such as these alkyl substituents, and different amino positions. Isomers. These curing agents can be used alone or in combination of two or more. Of these, diaminodiphenylmethane and diaminodiphenylsulfone are preferable from the viewpoint of imparting heat resistance to the composition.

  Examples of diaminodiphenyl sulfone include isomers such as 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, and 4,4'-diaminodiphenyl sulfone. From the viewpoint of heat resistance, 4,4′-diaminodiphenyl sulfone is particularly preferable.

  The optimum value of the amount added varies depending on the types and amounts of the [A] component and [B] component, and the type of curing agent. For example, in an aromatic amine curing agent, the stoichiometric equivalent ratio is preferably between 0.5 and 1.4 based on the total epoxy groups contained in the epoxy resin composition of the present invention, and more Preferably it is 0.6-1.4. When the equivalent ratio is less than 0.5, the curing reaction does not occur sufficiently, and curing failure may occur or the curing reaction may take a long time. When the equivalent ratio is larger than 1.4, the curing agent that is not consumed at the time of curing becomes a defect, which may deteriorate the mechanical properties.

  The curing agent can be used in either monomer or oligomer form. When mixing with the component [A] or the component [B], either powder or liquid may be used. These curing agents may be used alone or in combination. Moreover, you may use together a hardening accelerator.

  For example, combinations of aromatic polyamines and Lewis acid complexes, combinations of dicyandiamide and imidazole derivatives, combinations of dicyandiamide and urea compounds, and combinations such as aromatic polyamines, dicyandiamide and urea compounds are cured at relatively low temperatures. It is preferably used because high heat resistance and water resistance are obtained.

  The viscosity of the uncured product of the resin composition of the present invention is 50 to 50 ° C. in terms of processability when producing or using a prepreg, and from the viewpoint of suppressing the resin flow during curing of the prepreg. It is preferably 10,000 Pa · s. When the viscosity is less than 50 Pa · s, the tack may be too strong to recover when the prepreg is erroneously laminated, or the resin flow may be large and the physical properties of the fiber-reinforced composite material may not be stable. On the other hand, if it is greater than 10000 Pa · s, the formation of the prepreg may be poor and it may be difficult to form the curved surface.

  Carbon fibers, silicon carbide fibers, glass fibers, and aramid fibers are preferably used as the reinforcing fibers used in the prepreg and fiber-reinforced composite material of the present invention, and are particularly lightweight, high-performance, and fiber-reinforced composites with excellent mechanical properties. Carbon fiber is preferably used in that the material is obtained.

  Specific examples of carbon fibers that are preferably used as reinforcing fibers include acrylic, pitch, and rayon carbon fibers, and acrylic carbon fibers that have a particularly high tensile strength are preferably used.

  Such acrylic carbon fibers are obtained by spinning a spinning stock solution containing polyacrylonitrile obtained from a monomer containing acrylonitrile as a main component by a wet spinning method, a dry wet spinning method, a dry spinning method, or a melt spinning method, and spinning. The later coagulated yarn can be obtained through a yarn-making process to be a precursor, followed by steps such as flame resistance and carbonization.

  As the form of carbon fiber, twisted yarn, untwisted yarn, untwisted yarn, etc. can be used, but in the case of twisted yarn, the composition of the filaments constituting the reinforcing fiber bundle is not parallel, so the dynamics of the fiber reinforced composite material An untwisted yarn or a non-twisted yarn having a good balance between formability and strength properties of the fiber-reinforced composite material is preferably used because it may cause a decrease in properties.

  As the carbon fiber that is preferably used as the reinforcing fiber, any carbon fiber can be used as long as it is a known carbon fiber. However, the strand strength in the strand tensile test is 5000 MPa or more and 9500 MPa or less, and the elastic modulus is 270 GPa or more and 400 GPa. The following are preferably used. The strand tensile test refers to a test carried out based on JIS R7601 (1986) after impregnating a bundle of carbon fibers with a resin having the following composition and curing it at a temperature of 130 ° C. for 35 minutes.

[Resin composition]
3,4-epoxycyclohexylmethyl-3,4-epoxy-cyclohexyl-carboxylate (for example, ERL-4221, manufactured by Union Carbide Corp.): 100 parts by weight-boron trifluoride monoethylamine (for example, stellachemifa) (Manufactured by Co., Ltd.): 3 parts by mass. Acetone (for example, manufactured by Wako Pure Chemical Industries, Ltd.): 4 parts by mass.

  The number of filaments of carbon fiber is preferably 1,000 to 100,000, and more preferably 3000 to 50,000. When the number of carbon fiber filaments is less than 1000, the work for prepreging becomes complicated, and when the number is more than 100,000, it is difficult to impregnate the resin between the filaments and impregnation failure may occur.

  The kneading method of the epoxy resin composition used for the prepreg of the present invention may be any method as long as it is generally used for preparing the epoxy resin composition. For example, a kneader or a planetary mixer is used.

  The prepreg of the present invention can be produced by a wet method, a hot melt method, or the like described below.

  The wet method is a method in which reinforcing fibers are immersed in a solution of an epoxy resin composition, and then lifted and the solvent is evaporated using an oven or the like. The hot melt method is an epoxy resin composition whose viscosity is reduced by heating. Reinforced by directly impregnating the fiber with reinforcing fiber, or by preparing a film once coated with an epoxy resin composition on release paper, etc., and then overlaying the film from both sides or one side of the reinforcing fiber and heating and pressing This is a method of impregnating a fiber with a resin. The hot melt method is preferable because substantially no solvent remains in the prepreg.

The prepreg preferably has a reinforcing fiber amount of 70 to 1000 g / m ² per unit area. When the amount of the reinforcing fibers is less than 70 g / m ^2, it is necessary to increase the number of laminated layers in order to obtain a predetermined thickness when forming the fiber reinforced composite material, and the work may be complicated.

On the other hand, when the amount of reinforcing fibers exceeds 1000 g / m ² , the prepreg drapability tends to deteriorate. Moreover, the fiber content rate in a prepreg becomes like this. Preferably it is 30-90 mass%, More preferably, it is 35-85 mass%, More preferably, it is 40-80 mass%. When the fiber content is less than 30% by mass, the amount of the resin is too large, and the advantages of the fiber reinforced composite material excellent in specific strength and specific elastic modulus cannot be obtained. The calorific value may increase. On the other hand, if the fiber content exceeds 90% by mass, poor resin impregnation may occur, and the resulting composite material may have a large amount of voids.

  The drapeability referred to here is the flexibility of deformation of the prepreg, and is a characteristic that affects the shapeability of the mold during lamination. There are various evaluation methods for the drapeability index. For example, the prepared prepreg is cut to 300 mm in the 0 ° direction and 25 mm in the 90 ° direction, and is attached to the corner of the crossing stand by 100 mm and further fixed with tape. There is a method of measuring the bending angle θ of the prepreg by allowing it to stand for 5 minutes after fixing.

  The bending angle θ is an angle between a portion where the prepreg is not fixed and the side surface of the gantry, and θ takes a value of 0 to 90 °. For the bending angle θ, the distance from the side surface of the gantry and the height from the surface of the prepreg fixed to the gantry to the unfixed end of the prepreg are measured, and the bending angle θ is calculated from the tangent value. The higher the bending angle θ, the lower the drapability. If the drapeability is low, it is difficult to shape the curved surface. If the drapeability is too high, the wrinkles are likely to be close, so there is a range in which the handleability is good. A preferable bending angle θ is 30 to 65 °.

  After laminating the obtained prepreg, the fiber-reinforced composite material of the present invention consisting of a cured product of the epoxy resin composition and reinforcing fibers is produced by a method of heat curing the resin while applying pressure to the laminate.

  Examples of methods for applying heat and pressure include a press molding method, an autoclave molding method, a bagging molding method, a wrapping tape method, and an internal pressure molding method.

  The wrapping tape method is a method of winding a prepreg around a mandrel or other core metal to form a tubular body made of a fiber-reinforced composite material, and is a method suitable for producing a rod-shaped body such as a golf shaft or fishing rod. . More specifically, the prepreg is wound around a mandrel, and a wrapping tape made of a thermoplastic resin film is wound around the outside of the prepreg to fix and apply pressure to the prepreg. This is a method of extracting a gold to obtain a tubular body.

  Also, the internal pressure molding method is to set a preform in which a prepreg is wound on an internal pressure applying body such as a tube made of a thermoplastic resin in a mold, and then introduce a high pressure gas into the internal pressure applying body to apply pressure. At the same time, the mold is heated and molded. This method is preferably used when molding a complicated shape such as a golf shaft, a bad, a racket such as tennis or badminton.

  The curing temperature and time when the fiber-reinforced composite material of the present invention is molded in an autoclave or an oven vary depending on the type and amount of the selected curing agent and curing catalyst, but the heat resistance is 130 ° C. or higher. For applications that require high properties, it is preferable to cure at a temperature of 120 to 220 ° C. for 0.5 to 8 hours. A temperature increase rate of 0.1 to 10 ° C./min is preferably used. When the rate of temperature increase is less than 0.1 ° C./min, the time required to reach the target curing temperature becomes very long and workability may be reduced. On the other hand, if the rate of temperature rise exceeds 10 ° C./min, a temperature difference occurs in various portions of the reinforcing fibers, so that a uniform cured product may not be obtained.

When the fiber-reinforced composite material of the present invention is molded, pressure increase / decrease is not essential, but pressure increase / decrease may be performed as necessary. By increasing or decreasing the pressure, effects such as improvement of surface quality, suppression of internal voids, improvement of adhesion to metal or plastic to be bonded at the time of curing, or parts made of fiber reinforced composite material may be obtained.
Since the fiber-reinforced composite material of the present invention has high tensile strength and high impact resistance, it can be widely used in general industrial applications such as wind turbines, automobiles, and bicycles, including aerospace applications that require high mechanical properties. .

  Hereinafter, the epoxy resin composition of the present invention, and the prepreg and carbon fiber reinforced composite material using the epoxy resin composition of the present invention will be described more specifically with reference to examples. The production method and evaluation method of carbon fiber, resin raw material, prepreg and carbon fiber reinforced composite material used in the examples are shown below. The preparation environment and evaluation of the prepregs of the examples were performed in an atmosphere having a temperature of 25 ° C. ± 2 ° C. and a relative humidity of 50% unless otherwise specified.

  The particles 1 and 2 were prepared with reference to the pamphlet of International Publication No. 2009/142231.

<Component A>
MY0600 (m-aminophenol type epoxy resin, epoxy equivalent 118, manufactured by Huntsman Advanced Materials Co., Ltd.)
"Denacol (registered trademark)" Ex-201 (resorcinol type epoxy resin, epoxy equivalent 117, manufactured by Nagase ChemteX Corporation).

<Component B>
"Epiclon (registered trademark)" 830 (bisphenol F type epoxy resin, epoxy equivalent 170, manufactured by DIC Corporation)
"JER (registered trademark)" 630 (p-aminophenol type epoxy resin, epoxy equivalent 97.5, manufactured by Japan Epoxy Resins Co., Ltd.).

<Component C>
・ Particle 1 (“Trogamide (registered trademark)” CX7233 was used as a raw material, a particle having a particle diameter of 20 μm, a viscosity change of 0% at 80 ° C. for 2 hours)
(Manufacturing method of particle 1: Reference was made to the pamphlet of International Publication No. 2009/142231)
In a 1000 ml four-necked flask, 20 g of polyamide as polymer A (weight average molecular weight 17,000, “TROGAMID (registered trademark)” CX7323 manufactured by Degusa Co., Ltd.), 500 g of formic acid as an organic solvent, and 20 g of polyvinyl alcohol as polymer B (PVA 1000 manufactured by Wako Pure Chemical Industries, Ltd., SP value 32.8 (J / cm ³ ) ^1/2 ) was added, heated to 80 ° C., and stirred until the polymer was dissolved. After the temperature of the system was lowered to 55 ° C., 500 g of ion-exchanged water as a poor solvent was added at 0.5 g / min via a liquid feed pump while stirring at 900 rpm while continuing a sufficiently stirred state. The dripping was started at a speed of. The solution was dropped while gradually increasing the dropping speed, and the entire amount was dropped over 90 minutes. The system turned white when 100 g of ion exchange water was added. When half the amount of ion-exchanged water was dropped, the temperature of the system was raised to 60 ° C., then the remaining ion-exchanged water was added, and after the whole amount was dropped, stirring was continued for 30 minutes. The suspension returned to room temperature was filtered, washed with 500 g of ion-exchanged water, and vacuum-dried at 80 ° C. for 10 hours to obtain 11 g of a white solid. When the obtained powder was observed with a scanning electron microscope, it was polyamide fine particles having an average particle size of 19.5 μm and a particle size distribution index of 1.17.

・ Particle 2 (“Trogamide (registered trademark)” CX7323 was used as a raw material, a particle with a particle size of 30 μm, a viscosity change of 0% at 80 ° C. for 2 hours)
(Manufacturing method of particle 2: Reference was made to pamphlet of International Publication No. 2009/142231)
In a 1000 ml four-necked flask, 20 g of polyamide as polymer A (weight average molecular weight 17,000, “TROGAMID (registered trademark)” CX7323 manufactured by Degusa Co., Ltd.), 500 g of formic acid as an organic solvent, and 20 g of polyvinyl alcohol as polymer B (PVA 1000 manufactured by Wako Pure Chemical Industries, Ltd., SP value 32.8 (J / cm ³ ) ^1/2 ) was added, heated to 70 ° C., and stirred until the polymer was dissolved. While maintaining the temperature of the system as it is and sufficiently stirring, while stirring at 900 rpm, 600 g of ion exchange water as a poor solvent is passed through a liquid feed pump at a speed of 0.5 g / min. The dripping was started. The solution was dropped while gradually increasing the dropping speed, and the entire amount was dropped over 90 minutes. The system turned white when 100 g of ion exchange water was added. When half the amount of ion-exchanged water was dropped, the temperature of the system was raised to 60 ° C., then the remaining ion-exchanged water was added, and after the whole amount was dropped, stirring was continued for 30 minutes. The suspension returned to room temperature was filtered, washed with 500 g of ion-exchanged water, and vacuum-dried at 80 ° C. for 10 hours to obtain 11 g of a white solid. When the obtained powder was observed with a scanning electron microscope, it was a polyamide fine particle having an average particle size of 30.5 μm and a particle size distribution index of 1.46.

<Component D>
"Sumika Excel (registered trademark)" PES 5003P (polyethersulfone, manufactured by Sumitomo Chemical Co., Ltd.).

<Component E>
・ 4,4′-DDS (4,4′-diaminodiphenylsulfone, “Seika Cure (registered trademark)”-S, manufactured by Wakayama Seika Co., Ltd.)
-3,3′-DAS (3,3′-diaminodiphenylsulfone, manufactured by Mitsui Chemicals Fine Co., Ltd.).

<Other ingredients>
・ Particle 3 (Mizaberke Co., Ltd. "Grillamide (registered trademark)" TR-55 made particle size 15.2μm, viscosity change 2% at 80 ℃ 2 hours)
(Method for producing particle 3)
Polyamide containing 4,4′-diamino-3,3′dimethyldicyclohexylmethane as an essential constituent (“Glilamide (registered trademark)” TR-55 manufactured by Mzavelke Co., Ltd.), 94 parts by weight, epoxy resin (Japan Epoxy Resin) 4 parts by weight of “jER (registered trademark)” 828 manufactured by Co., Ltd. and 2 parts by weight of a curing agent (“Tomide (registered trademark)” # 296 manufactured by Fuji Kasei Kogyo Co., Ltd.), 300 parts by weight of chloroform and methanol It added in 100 weight part mixed solvent, and obtained the uniform solution. Next, the solution was atomized using a spray gun for coating, and sprayed toward the liquid surface of 3000 parts by weight of n-hexane, which was well stirred, to precipitate a solute. The precipitated solid was separated by filtration, washed well with n-hexane, and then vacuum dried at 100 ° C. for 24 hours to obtain transparent polyamide particles. When the obtained powder was observed with a scanning electron microscope, it was polyamide fine particles having an average particle size of 15.2 μm and a particle size distribution index of 2.10.

  Particle 4 (“Orgasol (registered trademark)” 1002D, particle size 20 μm, manufactured by Arkema Co., Ltd., viscosity change 100% at 80 ° C. for 2 hours).

<Reinforcing fiber>
Carbon fiber “Torayca (registered trademark)” T800GC-24K (manufactured by Toray Industries, Inc.).

(1) Preparation of prepreg The epoxy resin composition shown in Table 1 (in the table, the numbers represent parts by mass) was prepared, and coated on a release paper with a resin basis weight of 52 g / m ² using a knife coater. A film was prepared. This resin film is impregnated with an epoxy resin composition while being heated and pressed at 100 ° C. and 4 kg / cm ² using a heat roll by superimposing both sides of carbon fibers (weight per unit area 190 g / m ² ) aligned in one direction, The desired unidirectional prepreg was obtained.

(2) Viscosity measurement of uncured resin The viscosity of the uncured product of the epoxy resin composition was measured using a dynamic viscoelasticity measuring device ARES (manufactured by TA-Instruments), a parallel plate having a diameter of 40 mm, and a temperature increase rate of 2 The temperature was simply raised at ° C./min, and measurement was performed under the conditions of a frequency of 0.5 Hz and a gap of 1 mm. The temperature was raised from room temperature to 50 ° C., and the complex viscosity η ^* at 50 ° C. was recorded as the viscosity.

(3) Glass transition temperature of cured resin product The glass transition temperature of the cured resin product was measured using the differential calorimeter (DSC) as the glass transition temperature at the midpoint temperature determined based on JIS K7121 (1987). . The resin cured product was defoamed at 60 ° C. under vacuum and then cured in an oven at 1 atm, 180 ° C. for 2 hours.

(4) Measurement of 0 ° tensile strength of fiber reinforced composite material Cut the unidirectional prepreg obtained in (1) into a predetermined size, laminate 6 sheets in one direction, perform a vacuum bag, and use an autoclave. It was cured in 2 hours under the conditions of a temperature of 180 ° C. and a pressure of 6 kg / cm ² to obtain a unidirectional reinforcing material (carbon fiber reinforced composite material). This unidirectional reinforcing material was cut into a size of 12.7 mm in width and 230 mm in length, and a glass fiber reinforced plastic tab having a length of 1.2 mm and a length of 50 mm was bonded to both ends to obtain a test piece. This test piece was subjected to a 0 ° tensile test (measurement temperature −60 ° C.) according to the standard of JIS K7073 (1988) using an Instron universal testing machine.

(5) Interlaminar toughness test of fiber reinforced composite material Thirty unidirectional prepregs obtained in (1) were cut into a size of 200 × 250 mm and laminated so that the fiber directions were the same. Further, at the time of lamination, a polyimide film (thickness: 0.3 mm) subjected to mold release treatment was inserted into the central surface of the lamination so that the edge was perpendicular to the fiber direction in order to introduce an initial crack. The tip of the film was disposed at a position 40 mm from the edge of the laminate. This laminate was cured by heating and pressing for 2 hours in an autoclave under conditions of 180 ° C. and an internal pressure of 6 kg / cm ² to form a unidirectional fiber-reinforced composite material. The unidirectional fiber reinforced composite material was cut into 20 × 195 mm to obtain a test piece. This test piece was subjected to an ENF test in accordance with JIS K7086 (1993) appendix 2.

  Comparison between Examples 1, 3, 4, 6, and 7 and Comparative Examples 1 and 5 reveals that the interlaminar toughness and tensile strength are lowered depending on the presence or absence of the [A] component. Comparison between Examples 4 and 6 and Comparative Examples 2 and 3 reveals that the interlayer toughness decreases depending on the presence or absence of the [C] component. From the comparison between Examples 2, 4, and 5 and Comparative Example 4, it can be seen that the tensile strength decreases depending on the presence or absence of the [B] component.

  Since the carbon fiber reinforced composite material obtained by the epoxy resin composition of the present invention is excellent in interlaminar shear strength and tensile strength, in addition to effects such as weight reduction in conventional applications, it is widely used in structural members that have been difficult to apply so far. It is possible to apply.

  For example, in aerospace applications, primary structural materials such as aircraft main wings, tail wings and floor beams, secondary structural materials such as flaps, ailerons, cowls, fairings and interior materials, rocket motor cases and satellite structural materials It is used suitably for etc. In general industrial applications, structural materials for moving bodies such as automobiles, ships, and railway vehicles, drive shafts, leaf springs, windmill blades, pressure vessels, flywheels, paper rollers, roofing materials, cables, reinforcement bars, and repair reinforcement materials It is suitably used for civil engineering and building material applications. Further, in sports applications, it is suitably used for golf shafts, fishing rods, tennis, badminton and squash rackets, hockey sticks, skates, ski poles, and the like.

Claims (8)

An epoxy resin composition comprising the following [A] to [E].
[A] Bifunctional or higher functional epoxy resin having a glycidyl ether group at the meta position [B] Bifunctional or higher functional epoxy resin other than [A] [C] Insoluble in epoxy resin having a structure represented by the general formula (1) Resin particles

(In the formula, R ₁ and R ₂ represent an alkyl group having 1 to 8 carbon atoms and a halogen element, and may be the same or different. R ₃ represents a methylene group having 1 to 20 carbon atoms. )
[D] Thermoplastic resin soluble in epoxy resin [E] Epoxy resin curing agent The epoxy resin composition according to claim 1, wherein [A] is a resorcinol type epoxy resin or an m-aminophenol type epoxy resin. The epoxy resin composition according to claim 1 or 2, wherein at least one of [B] is bifunctional or more and is liquid at room temperature. The epoxy resin composition according to any one of claims 1 to 3, wherein [D] is polyethersulfone, polyetherimide, or polyphenylene ether. The epoxy resin composition according to any one of claims 1 to 4, wherein [E] is an aromatic polyamine curing agent. The epoxy resin composition according to any one of claims 1 to 5, wherein [E] is diaminodiphenyl sulfone, or a derivative or isomer thereof. A prepreg obtained by impregnating reinforcing fibers with the epoxy resin composition according to claim 1. A fiber-reinforced composite material comprising a cured product of the epoxy resin composition according to claim 1 and reinforcing fibers.