JP2007154088A - Two-pot type curable resin composition for fiber-reinforced composite material, fiber-reinforced composite material and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a two-pot type curable resin composition for a fiber-reinforced composite material suitable for an RTM (resin transfer molding) method, very excellent in toughness, and the RTM-molded fiber-reinforced composite material having a high compressive strength after getting an impact by applying the two-pot type curable resin composition for the fiber-reinforced composite material. <P>SOLUTION: This two-pot type curable resin composition for a fiber-reinforced composite material consists of (A) a liquid composition containing (A1) an alicyclic epoxy resin and (A2) a methacrylic acid ester compound, and having ≤500 mPa s viscosity at 40°C and (B) a liquid composition containing (B1) an aliphatic polyamine compound and (B2) a radical polymerization initiator generating radicals, and having ≤500 mPa s viscosity at 40°C, and it is possible to heat and cure the resin by mixing the liquid compositions (A) with (B). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a two-component curable resin composition for a fiber-reinforced composite material for a fiber-reinforced composite material suitably used for aircraft members, spacecraft members, automobile members, ship members, and the like. The present invention relates to a two-part curable resin composition for a fiber-reinforced composite material and a fiber-reinforced composite material using the same for a fiber-reinforced composite material having very excellent fracture toughness.

  Conventionally, fiber reinforced composite materials consisting of reinforcing fibers such as glass fiber, carbon fiber and aramid fiber, and thermosetting resins such as unsaturated polyester resin, vinyl ester resin, epoxy resin, phenol resin, cyanate resin and bismaleimide resin have been It is lightweight, but it has excellent mechanical properties such as strength, rigidity, impact resistance and fatigue resistance, heat resistance, and corrosion resistance, so it can be used in aircraft, spacecraft, automobiles, railway vehicles, ships, civil engineering and sports. It has been applied to many fields such as supplies. Especially in applications where high performance is required, fiber reinforced composite materials using continuous reinforcing fibers are used. Carbon fibers are used as reinforcing fibers, thermosetting resins are used as matrix resins, and epoxy resins are particularly common. It is used.

  When a fiber reinforced composite material is used as a structural material for the above applications, compression characteristics and impact resistance become important. Regarding these two characteristics, particularly important physical properties include post-impact compressive strength (hereinafter sometimes abbreviated as CAI). This is an impact on a member using a fiber reinforced composite material due to the impact of a tool drop or pebbles, etc., and even if there is no apparent damage, peeling occurs between the layers of the fiber reinforced composite material, reducing the compressive strength Although this phenomenon is known, it is a characteristic representing the compressive strength after such damage, and if this CAI is significantly lowered, it cannot be used as a structural material.

  In order to improve the CAI, it is effective to increase the toughness of the thermosetting resin and suppress internal damage such as delamination when subjected to an impact, and heat as a component for increasing the toughness of the thermosetting resin. It is effective to add a plastic resin component. In the prepreg method, which is one of the methods for molding fiber-reinforced composite materials, this problem is solved by a method of laminating and curing a prepreg provided with a thermoplastic resin. Various proposals have been made regarding the form of the thermoplastic resin applied to the prepreg (see Patent Documents 1 to 12).

However, in recent years, resin transfer molding (resin transfer molding), in which application is expanded due to a high potential for reducing molding cost, in which a liquid thermosetting resin is directly impregnated into a reinforcing fiber base and cured, In the method, there is a restriction on the resin design that when the thermosetting resin is injected into the reinforced fiber base material, it must be in a low-viscosity liquid state, as in the prepreg method. The method of increasing the toughness of the thermosetting resin by adding a thermoplastic resin component cannot be applied because the viscosity is remarkably increased, and the CAI generally tends to be low. Therefore, in a fiber reinforced composite material molded by the RTM method, a method for increasing CAI, that is, increasing the toughness of the matrix resin has been desired.
European Patent No. 0366979A2 Specification European Patent No. 0495518A1 Japanese Patent Laid-Open No. 01-320146 Japanese Patent Laid-Open No. 05-287091 European Patent No. 0274899A2 European Patent No. 0707032A1 US Pat. No. 4,874,661 European Patent No. 0488389A2 Japanese Patent Laid-Open No. 08-176322 Japanese Patent Laid-Open No. 02-032843 European Patent No. 0657492A1 Japanese Patent Application Laid-Open No. 08-048796

  An object of the present invention is to provide a two-part curable resin composition for a fiber-reinforced composite material and an optimum two-part type curable resin composition for the fiber-reinforced composite material, which is most suitable for the RTM method with excellent toughness. Another object of the present invention is to provide a fiber-reinforced composite material that has a high compressive strength after impact by applying a functional resin composition and is optimal as a member for an aircraft primary structure or the like.

  The present invention employs the following means in order to solve such problems. That is, the two-component curable resin composition for a fiber-reinforced composite material of the present invention includes a liquid composition having an alicyclic epoxy resin (A1) and a methacrylic acid ester compound (A2) and having a viscosity at 40 ° C. of 500 mPa · s or less. And a liquid composition (B) having a viscosity at 40 ° C. of 500 mPa · s or less, comprising a product (A), an aliphatic polyamine compound (B1), and a radical polymerization initiator (B2) that generates radicals upon heating. It is a two-component curable resin composition for fiber-reinforced composite materials that can be heat-cured by mixing the composition (A) and the liquid composition (B).

  According to a preferred embodiment of the two-component curable resin composition for fiber-reinforced composite material of the present invention, the methacrylic acid ester compound (A2) is blended in the liquid composition (A) in an amount of 1 to 40% by weight. In the methacrylic acid ester compound (A2), 1 to 20% by weight of a compound having an unsaturated group and one or more functional groups is blended, and the compound having an unsaturated group and one or more functional groups Includes glycidyl methacrylate.

Moreover, according to the preferable aspect of the two-component curable resin composition for fiber-reinforced composite materials of the present invention, the mixture of the liquid composition (A) and the liquid composition (B) is 40 ° C. The initial viscosity is 500 mPa · s or less, and the GIc of the cured product obtained by heating and curing a mixture of the liquid composition (A) and the liquid composition (B) at a temperature of 180 ° C. for 2 hours is 150 J / m ² or more.

  The fiber-reinforced composite material of the present invention is composed of the two-component curable resin composition for fiber-reinforced composite material and the reinforcing fiber, and according to a preferred embodiment of the fiber-reinforced composite material of the present invention, The reinforcing fibers are carbon fibers, and the volume content of the reinforcing fibers is 50 to 65%.

  Furthermore, in the method for producing a fiber-reinforced composite material of the present invention, a fabric containing reinforcing fibers arranged in a mold is injected and impregnated by injecting the two-component curable resin composition for fiber-reinforced composite material, It is characterized by being heat-cured.

  According to the present invention, a two-component curable resin composition for fiber-reinforced composite material having a very excellent toughness while maintaining a low viscosity suitable for the RTM method is obtained. A fiber-reinforced composite material composed of a two-component curable resin composition and reinforcing fibers has a high post-impact compressive strength (CAI) and is therefore suitable for structural members such as aircraft members, spacecraft members, automobile members, and ship members. Can be used for

  The two-component curable resin composition for fiber-reinforced composite materials of the present invention is a liquid composition having an alicyclic epoxy resin (A1) and a methacrylic ester compound (A2) and having a viscosity at 40 ° C. of 500 mPa · s or less. A liquid composition (B) having a viscosity at 40 ° C. of 500 mPa · s or less containing A), an aliphatic polyamine compound (B1), and a radical polymerization initiator (B2) that generates radicals upon heating.

  The liquid composition (A) used in the present invention is a composition composed of a thermosetting monomer or oligomer, while the liquid composition (B) used in the present invention is the liquid composition described above. It is a composition composed of a compound that has the ability to cure (A). By separating both components into a two-part type, there is no limit on the storage period as in the one-part type, and special temperature control is also required. And not.

  The alicyclic epoxy resin (A1) constituting the liquid composition (A) used in the present invention is an epoxy resin having 1,2-epoxycycloalkane as a partial structure, and is used alone or in a mixture of plural kinds. be able to. Examples of such alicyclic epoxy resins include vinylcyclohexene diepoxide, 3,4-epoxycyclohexanecarboxylic acid-3,4-epoxycyclohexylmethyl, bis3,4-epoxycyclohexylmethyl adipate, dicyclopentadiene diepoxide, ε-caprolactone-modified bis (3,4-epoxycyclohexylmethyl) -4,5-epoxycyclohexane-1,2-dicarboxylic acid, ε-caprolactone-modified tetra (3,4-epoxycyclohexylmethyl) butane-tetracarboxylic acid, dipentene Dioxide, 1,4-cyclooctadiene diepoxide, bis (2,3-epoxycyclopentyl) ether, and the like can be used.

  The amount of the alicyclic epoxy resin (A1) in the liquid composition (A) is preferably 60 to 99% by weight, more preferably 65 to 97% by weight. When the blending amount of the alicyclic epoxy resin (A1) is less than 60% by weight in the liquid composition (A), the heat resistance and elastic modulus necessary for the fiber-reinforced composite material cannot be obtained, and the blending amount is If it exceeds 99% by weight, high fracture toughness may not be obtained.

  The liquid composition (A) has two or more epoxy groups in one molecule other than the alicyclic epoxy resin in order to improve the mechanical properties such as heat resistance and elastic modulus of the cured resin obtained by thermosetting. The epoxy resin having is preferably 1 to 40% by weight in the liquid composition (A).

  Examples of such an epoxy resin include bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, tetrabromobisphenol A diglycidyl ether, bisphenol AD diglycidyl ether, 2,2 ′, 6,6′-tetramethyl-4,4. '-Biphenol diglycidyl ether, N, N, O-triglycidyl-m-aminophenol, N, N, O-triglycidyl-p-aminophenol, N, N, O-triglycidyl-4-amino-3- Methylphenol, N, N-diglycidylaniline, N, N-diglycidyl-o-toluidine, N, N, N ′, N′-tetraglycidyl-4,4′-methylenedianiline, N, N, N ′, N′-tetraglycidyl-2,2′-diethyl-4,4′-methylenedianiline, , N, N ′, N′-tetraglycidyl-m-xylylenediamine, 1,3-bis (diglycidylaminomethyl) cyclohexane, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, hexamethylene glycol diglycidyl ether, Neopentyl glycol diglycidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, diglycidyl phthalate, diglycidyl terephthalate, diglycidyl ether of 1,6-dihydroxynaphthalene, 9,9- Diglycidyl ether of bis (4-hydroxyphenyl) fluorene, triglycidyl ether of tris (p-hydroxyphenyl) methane, tetrakis ( -Hydroxyphenyl) ethane tetraglycidyl ether, phenol novolac glycidyl ether, cresol novolac glycidyl ether, glycidyl ether of a condensate of phenol and dicyclopentadiene, glycidyl ether of phenol aralkyl resin, triglycidyl isocyanurate, N-glycidyl phthalimide, 5 -Ethyl-1,3-diglycidyl-5-methylhydantoin, 1,3-diglycidyl-5,5-dimethylhydantoin, oxazolidone type epoxy resin obtained by addition of bisphenol A diglycidyl ether and tolylene isocyanate, and phenol aralkyl type Epoxy or the like can be used.

  The methacrylic acid ester compound (A2) constituting the liquid composition (A) used in the present invention is a compound obtained by esterification of methacrylic acid and various alcohol compounds, and can be used alone or in a mixture of plural kinds. it can. Examples of the methacrylic acid ester compound (A2) include methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, tertiary butyl methacrylate, propyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, and methacrylic acid. Octyl acid, benzyl methacrylate, isodecyl methacrylate, lauryl methacrylate, tridecyl methacrylate, lauryl methacrylate-tridecyl methacrylate, stearyl methacrylate, isobornyl methacrylate, dicyclopentanyl methacrylate, dicyclopentanyloxyethyl methacrylate, dimethacryl Acid ethylene glycol, dimethacrylic acid triethylene glycol, dimethacrylic acid tetraethylene glycol, dimethacrylic acid-1,3-butyl Lenglycol, dimethacrylic acid-1,4-butanediol, dimethacrylic acid-1,6-hexanediol, glyceryl dimethacrylate, trimethylolpropane trimethacrylate, bisphenol A ethylene oxide adduct, and dimethacrylic acid Bisphenol A propylene oxide adducts and the like can be used.

  The amount of the methacrylic acid ester compound (A2) in the liquid composition (A) is preferably 1 to 40% by weight, more preferably 3 to 35% by weight. When the blending amount of the methacrylic ester compound (A2) is less than 1% by weight in the liquid composition (A), high toughness cannot be obtained, and when the blending amount is more than 40% by weight, the composition is heated and cured. The heat resistance and elastic modulus of the cured resin product obtained in this way may be reduced.

  In the present invention, the methacrylic acid ester compound (A2) may contain a compound having an unsaturated group and one or more functional groups in order to improve the adhesion to the alicyclic epoxy resin (A1). it can. Examples of the compound having an unsaturated group and one or more functional groups include methacrylic acid, diethylaminoethyl methacrylate, 2-hydroxyethyl methacrylate, tertiary butylaminoethyl methacrylate, 2-hydroxypropyl methacrylate, methacrylic acid. Glycidyl acid, dimethylaminoethyl methacrylate, tetrahydrofurfuryl methacrylate, etc. can be used, and especially glycidyl methacrylate has good adhesion when used in the reaction of alicyclic epoxy resin and aliphatic polyamine. This is a particularly preferred embodiment in the present invention.

  The compound having an unsaturated group and one or more functional groups is preferably added in an amount of 1 to 20% by weight, more preferably 5 to 15% by weight, in the methacrylic acid ester compound (A2). When the blending amount of the compound having an unsaturated group and one or more functional groups in the methacrylic acid ester compound is less than 1% by weight, the adhesion with the alicyclic epoxy resin (A1) is insufficient, and blending When the amount is more than 20% by weight, the toughness may be lowered by forming an excessive cross-linked structure.

In the present invention, the liquid composition (A) has a viscosity at 40 ° C. of 500 mPa · s or less, and a preferred viscosity is 400 mPa · s or less. When the viscosity at 40 ° C. is higher than 500 mPa · s, workability such as taking out the fiber-reinforced composite material from the molded container, weighing, mixing with the liquid composition (B), or degassing treatment is deteriorated after curing. Sometimes. The lower limit of the viscosity at 40 ° C. is not particularly limited, and the lower the viscosity, the easier the injection impregnation of the two-component curable resin composition for fiber-reinforced composite material in RTM molding is preferable.
In order to make the viscosity at 40 ° C. of the liquid composition (A) 500 mPa · s or less, an epoxy resin other than the alicyclic epoxy resin (A1) and the alicyclic epoxy resin (A1) having a molecular weight of 500 or more is used. The liquid composition (A) is preferably not blended by 30% by weight or more. More preferably, these epoxy resins are not included.

  As the aliphatic polyamine compound (B1) constituting the liquid composition (B) used in the present invention, a chain aliphatic polyamine compound and an alicyclic polyamine compound are suitable, and they are used alone or in a mixture of plural kinds. be able to.

  Examples of the chain aliphatic polyamine compound include diethylenetriamine, tetraethylenepentamine, hexamethylenediamine, 1,3-pentanediamine, and 2-methylpentamethylenediamine.

  Examples of the alicyclic polyamine compound include isophorone diamine, 4,4′-methylenebiscyclohexylamine, 4,4′-methylenebis (2-methylcyclohexylamine), bis (aminomethyl) norbornane, 1,2 -Cyclohexanediamine, 1,3-bisaminomethylcyclohexane, etc. are mentioned.

  Among these, alicyclic polyamines are preferably used in that high heat resistance and elastic modulus can be obtained in a cured resin obtained by heat curing.

  The blending amount of the aliphatic polyamine (B1) in the liquid composition (B) is preferably 60 to 99.5% by weight, more preferably 65 to 99% by weight. When the blending amount of the aliphatic polyamine (B1) is less than 65% by weight in the liquid composition (B), mechanical properties such as heat resistance and elastic modulus may be deteriorated, and the blending amount is 99.5. When the amount is more than% by weight, the amount of the acid catalyst and radical polymerization initiator (B2) described later is insufficient, which may cause curing failure.

  Usually, the alicyclic epoxy resin (A1) is inferior in reactivity with the aliphatic polyamine compound (B1). However, in the presence of an acid catalyst, protons and Lewis acids are coordinated to the oxygen atom of the epoxy group, making it easier to undergo nucleophilic substitution and curing under practical reaction conditions.

  Also in the present invention, an acid catalyst can be used in combination with the aliphatic polyamine compound (B1). As the acid catalyst, strong acid esters, Lewis acid and base complexes, and the like can be used.

  Examples of such strong acid esters include sulfuric acid, sulfonic acid, phosphoric acid, phosphinic acid and phosphonic acid esters. When the strong acid is a so-called polybasic acid, in order to have the potential, it is necessary that the ionizable hydrogen atom in the molecule is an ester substituted with an organic substituent.

  Examples of the complex of Lewis acid and base include boron trifluoride / aniline complex, boron trifluoride / p-chloroaniline complex, boron trifluoride / ethylamine complex, boron trifluoride / isopropylamine complex, 3 Boron fluoride / benzylamine complex, boron trifluoride / dimethylamine complex, boron trifluoride / diethylamine complex, boron trifluoride / dibutylamine complex, boron trifluoride / piperidine complex, boron trifluoride / dibenzylamine And a complex and boron trichloride / dimethyloctylamine complex.

  The compounding amount of the acid catalyst in the liquid composition (B) is preferably 0.3 to 32% by weight, more preferably 0.5 to 0.5% by weight. When the compounding amount of the acid catalyst is less than 0.3% by weight in the liquid composition (B), good curability cannot be obtained, and when the compounding amount is more than 32% by weight, a runaway reaction occurs. there is a possibility.

  As the radical polymerization initiator (B2) that generates radicals by heating that constitutes the liquid composition (B) used in the present invention, an azo compound, an organic peroxide, or the like can be used.

  As such an azo compound, for example, 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile) and the like can be used.

  Examples of the organic peroxide include 1,1-bis (t-butylperoxy) -2,2,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclododecane, 1,1 , 3,3-tetramethylhydroperoxide, 1,1-dimethylbutyl peroxide, bis (1-tert-butylperoxy-1-methylethyl) benzene, dicumyl peroxide, 2,5-dimethyl-2,5-bis ( t-butylperoxy) hexane, t-butylcumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne, benzoyl peroxide, lauroyl peroxide, peroxide Decanoyl, dicyclohexyl peroxydicarbonate, bis (4-t-butylcyclohexyl) peroxydi -Bonate, t-butyl 2-ethyl perhexanoate, (1,1-dimethylpropyl) 2-ethyl perhexanoate, (1,1-dimethylbutyl) 2-ethyl perhexanoate, t-butyl 3, 5,5-trimethylperhexanoate, isopropyl peroxycarbonate = 1,1-dimethylbutyl, t-butylperoxyisopropyl carbonate, t-butylperoxy-2-ethylhexyl carbonate, t-butyl permaleate, t-perlaurate Butyl, t-butyl perbenzoate, and the like can be used. These radical polymerization initiators may be used alone or in combination.

  The blending amount of the radical polymerization initiator (B2) in the liquid composition (B) is preferably 0.001 to 8% by weight, more preferably 0.002 to 7% by weight. When the blending amount of the radical polymerization initiator (B2) is less than 0.001% by weight in the liquid composition (B), the polymerization of the methacrylic acid ester compound (A2) is completed incompletely and high toughness is obtained. In addition, when the blending amount is more than 8% by weight, the heat resistance may be lowered due to a decrease in the molecular weight of the polymer of the methacrylic ester compound (A2).

  The liquid composition (B) used in the present invention may further contain a polymerization inhibitor or accelerator of a polymerization initiator (B2) that generates radicals upon heating.

  As such a polymerization inhibitor, for example, 2,6-di-t-butyl-p-cresol, 2,2′-methylenebis (4-methyl-6-t-butylphenol), 2,2′-methylenebis (4- Ethyl-6-t-butylphenol), 4,4'-thiobis (2-methyl-6-t-butylphenol), hydroquinone, 2-t-butylhydroquinone, 2,5-di-t-butylhydroquinone, p-benzoquinone 2-ethylanthraquinone, dilauryl thiodipropionate, cuperone, and the like can be used.

  Further, as a promoter, a transition metal salt such as cobalt naphthenate can be used.

  In the present invention, the viscosity of the liquid composition (B) at 40 ° C. is 500 mPa · s or less, and the preferred viscosity is 400 mPa · s or less. When the viscosity at 40 ° C. is higher than 500 mPa · s, workability such as taking out from the container, weighing, mixing with the liquid composition (A), or degassing treatment may be deteriorated. The lower limit of the viscosity at 40 ° C. is not particularly limited, and the lower the viscosity, the easier the injection impregnation of the two-component curable resin for fiber-reinforced composite material in RTM molding is preferable.

  In order to reduce the viscosity at 40 ° C. of the liquid composition (B) to 500 mPa · s or less, it is necessary to mix 80% by weight or more of the aliphatic polyamine compound having low crystallinity in the aliphatic polyamine compound (B1). is there. When the polyamine compound having low crystallinity is 80% by weight or less in the aliphatic polyamine compound (B1), there is a possibility that a crystalline substance precipitates during storage and thickens or solidifies.

  In the liquid composition (A) and the liquid composition (B) constituting the two-component curable resin composition for fiber-reinforced composite material of the present invention, as other components, a plasticizer, a dye, an organic pigment, and an inorganic filler An agent, a polymer compound, a coupling agent, a surfactant, and the like can be appropriately blended.

The two-component curable resin composition for fiber-reinforced composite materials of the present invention can be heat-cured by mixing the liquid composition (A) and the liquid composition (B) at a suitable predetermined ratio.
The mixing ratio of the liquid composition (A) and the liquid composition (B) is determined by the type of the alicyclic epoxy resin (A1) to be used and the other epoxy resin and the aliphatic polyamine compound (B1). Specifically, the number of epoxy groups contained in all epoxy resins in the liquid composition (A) and active hydrogen contained in all polyamine compounds in the liquid composition (B) (active hydrogen is nitrogen in organic compounds, The hydrogen atom is bonded to oxygen, sulfur or the like and is a highly reactive hydrogen atom), and the ratio is preferably 0.7 to 1.3, more preferably 0.8 to 1.2. . When the ratio between the epoxy group and the active hydrogen is out of the above range, the heat resistance and elastic modulus of the obtained resin cured product may be lowered.

  The resin cured product of the two-component curable resin composition for fiber-reinforced composite material is preferably in the range of 50 to 200 ° C. depending on the activity of the aliphatic polyamine compound (B1) constituting the liquid composition (B). It is preferably obtained by heating and curing at an arbitrary temperature of 0.5 to 10 hours. The heating condition may be one stage or may be a multistage condition in which a plurality of heating conditions are combined. Assuming an aircraft structural member, the final curing condition is, for example, a desired resin cured product can be obtained by curing at a temperature of 180 ° C. for 1 to 10 hours. The two-component curable resin composition for fiber-reinforced composite material of the present invention, during curing, a polyaddition reaction between an alicyclic epoxy resin (A1) and an aliphatic polyamine compound (B1), and a methacrylic acid ester compound (A2). ) And the radical polymerization initiator (B2) proceed in parallel, the polyaddition reaction product forms a continuous phase, and the radical reaction product forms a dispersed phase to form a sea-island structure.

  When the cured resin forms a sea-island structure, even if cracks due to impact occur in the cured epoxy resin that is a brittle material of the continuous phase, the acrylic resin that is the dispersed phase prevents the propagation of cracks and improves toughness.

In the present invention, fracture toughness (GIc), which is an index of toughness of a cured resin obtained by heat-curing a mixture of the two-component curable resin composition for fiber-reinforced composite material of the present invention at 180 ° C. for 2 hours, is , Preferably 150 J / m ² or more, more preferably 200 J / m ² or more. When GIc is smaller than 150 J / m ^2, when an impact is applied to the obtained fiber-reinforced composite material, the propagation of cracks cannot be prevented, and the CAI tends to decrease. There is no restriction | limiting in particular about the upper limit of fracture toughness (GIc), CAI of the fiber reinforced composite material obtained so that the numerical value is high improves.

  The two-component curable resin composition for a fiber-reinforced composite material of the present invention is suitably used for the production of a fiber-reinforced composite material using an RTM (Resin Transfer Molding) method. In the RTM method, a fiber substrate or preform made of reinforcing fibers is placed in a mold, and a two-part curable resin composition for fiber-reinforced composite material, which is a liquid matrix resin, is injected into the mold. In this method, the fiber is impregnated and then heated to cure the two-component curable resin composition for fiber-reinforced composite material to obtain a fiber-reinforced composite material as a molded product.

  Examples of the reinforcing fiber used in the present invention include carbon fiber, glass fiber, and aramid fiber, and carbon fiber is preferably used in that a lightweight and high-performance fiber-reinforced composite material can be obtained.

  Specific examples of the carbon fibers in the present invention include acrylic, pitch, and rayon carbon fibers, and acrylic carbon fibers having particularly high tensile strength are preferably used. As the form of the carbon fiber, twisted yarn, untwisted yarn, untwisted yarn and the like can be used, but untwisted yarn or untwisted yarn is preferably used because the balance between moldability and strength characteristics of the fiber reinforced composite material is good.

  The elastic modulus of the carbon fiber is preferably in the range of 200 GPa to 400 GPa from the viewpoint of the characteristics and weight of the molded structural member. If the elastic modulus is lower than this range, the rigidity of the structural member may be insufficient and weight reduction may be insufficient. Conversely, if the elastic modulus is higher than this range, the strength of the carbon fiber generally tends to decrease. A more preferable elastic modulus is in the range of 250 GPa to 370 GPa, and more preferably in the range of 290 GPa to 350 GPa.

  In the present invention, the fiber base material composed of reinforcing fibers is composed of reinforcing fibers alone or in combination with a plurality of types, and further, if necessary, combined with other chemical fibers, etc., and as a form, the fiber directions are aligned substantially in the same direction. Woven fabrics, knitted fabrics, braids and mats can be used. However, in particular, the reinforcing fiber is substantially used in that a fiber reinforced composite material having high mechanical properties and a high volume content of the reinforcing fiber can be obtained. In particular, a so-called unidirectional fabric that is oriented in one direction and fixed with glass fiber or chemical fiber is preferably used.

Examples of the unidirectional woven fabric include strands made of carbon fibers arranged in parallel in one direction as warps, and wefts made of glass fibers or chemical fibers intersecting with each other to form a plain weave structure. , Consisting of a warp made of carbon fiber strands, an auxiliary warp of a fiber bundle made of glass fibers or chemical fibers arranged parallel to this, and a weft made of glass fibers or chemical fibers arranged so as to be orthogonal thereto, Non-crimped woven fabrics and the like in which the woven fabric is formed by holding the carbon fiber strands integrally by crossing the auxiliary warps and the wefts.
In the present invention, the fiber reinforced composite material preferably has a reinforcing fiber volume content of 50 to 65%, and more preferably 53 to 60%. When the volume content is less than the above range, the weight of the fiber-reinforced composite material becomes heavy, and the strength tends to decrease due to the influence of stress concentration. Further, when the volume content of the reinforcing fiber is larger than the above range, a defect portion such as an unimpregnated portion or a void is very often generated inside the fiber reinforced composite material, which may cause deterioration in physical properties.

  As a preferable molding method of the fiber reinforced composite material in the present invention, a two-part curable resin composition for a fiber reinforced composite material is preferably 25 to 90 ° C. in a preform composed of a reinforced fiber base disposed in a mold. Inject at an arbitrary temperature in the range of Therefore, the initial viscosity of the two-component curable resin composition for fiber-reinforced composite materials is preferably 500 mPa · s or less at 40 ° C., and more preferably 300 mPa · s or less. When the initial viscosity is higher than the above range, the impregnation property of the epoxy resin composition may be insufficient. The lower limit of the viscosity at 40 ° C. is not particularly limited, and the lower the viscosity, the easier the injection impregnation of the two-component curable resin composition for fiber-reinforced composite material in RTM molding.

  In the present invention, the mold used for the RTM molding may be a closed mold made of a rigid body, or may be a rigid open mold and a flexible film (bag). In the latter case, the fiber substrate made of reinforcing fibers can be placed between the rigid open mold and the flexible film.

  As the rigid material, various kinds of existing materials such as metals such as steel and aluminum, fiber reinforced plastic (FRP), wood and gypsum are used. Nylon, fluorine resin, silicone resin, or the like is used as the material for the flexible film.

  When a rigid closed mold is used, it is usually performed by pressurizing and clamping and injecting and injecting the two-component curable resin composition for fiber-reinforced composite material. At this time, it is also possible to provide a suction port separately from the injection port and connect it to a vacuum pump for suction. It is also possible to inject the two-component curable resin composition for fiber-reinforced composite material only at atmospheric pressure without performing a suction and using a special pressurizing means.

  In the case of using a rigid open mold and a flexible film, suction and injection by atmospheric pressure are usually used. In order to achieve good impregnation by injection at atmospheric pressure, it is effective to use a resin diffusion medium. Furthermore, it is also preferable to apply a gel coat to a rigid surface prior to the installation of a fiber substrate or preform made of reinforcing fibers.

After the installation of the fiber base material or preform made of reinforced fibers is completed, mold clamping or bagging is performed, and then a two-part curable resin composition for fiber reinforced composite material is injected, followed by heat curing. Is done. The temperature of the mold at the time of heat curing is usually selected to be higher than the temperature of the mold at the time of injection of the two-component curable resin composition for fiber reinforced composite material. The mold temperature during heat curing is preferably 80 to 180 ° C. The time for heat curing is preferably 1 to 20 hours. After the heat curing is completed, the mold is removed and the fiber reinforced composite material is taken out. Thereafter, the obtained fiber-reinforced composite material may be post-cured by heating at a temperature higher than the curing temperature. The post-curing temperature is preferably 150 to 200 ° C., and the time is preferably 1 to 4 hours.
The fiber-reinforced composite material obtained by the above-described RTM molding using the two-component curable resin composition for fiber-reinforced composite material of the present invention exhibits high post-impact compressive strength (CAI). With respect to the fiber reinforced composite material having a thickness of 4 to 5 mm obtained from the preform cross-laminated with the CAI and the two-component curable resin composition for fiber reinforced composite material, a test piece of 1 mm according to JIS K 7089 (1996) is used. The residual compressive strength after applying an impact energy of 20 J per unit, and CAI is preferably 190 MPa or more, and more preferably 200 MPa or more. When the CAI is lower than 190 MPa, the strength may be insufficient, and it cannot be used particularly for structural members such as aircraft. There is no restriction | limiting in particular about the upper limit of CAI, The safety | security when a fiber reinforced composite material is applied as a structural member is so high that a numerical value is high.

  The fiber-reinforced composite material of the present invention is light because of the high volume content of the reinforcing fiber, and is excellent in impact resistance, particularly compressive strength after impact (CAI). The fuselage, main wing, tail wing, moving blade, fairing, cowl Aircraft parts such as doors, seats and interior materials, spacecraft parts such as motor cases and main wings, satellite members such as structures and antennas, automobile parts such as outer plates, chassis, aerodynamic members and seats, structures and seats, etc. It can be suitably used for many structural materials such as railway vehicle members, ship members such as hulls and seats.

  Hereinafter, the two-part curable resin composition for fiber-reinforced composite material and the fiber-reinforced composite material of the present invention will be described more specifically with reference to examples. The unit “parts” of the composition ratio means “parts by weight” unless otherwise noted.

<Measurement method of resin viscosity>
Liquid composition (A), liquid composition (B), and liquid composition (A) and liquid composition (B) constituting the two-component curable resin composition for fiber-reinforced composite materials obtained in the examples The viscosities of each of the mixtures according to JIS Z8803 (1991) according to “Viscosity measurement method using a cone-plate rotary viscometer” (E type viscometer equipped with a standard cone rotor (1 ° 34 ′ × R24) ) Viscosity at a predetermined temperature was measured at a rotational speed of 50 revolutions / minute using Tokimec, TVE-30H

<Method of measuring fracture toughness (GIc) of cured resin>
The two-component curable resin composition for fiber-reinforced composite materials obtained in the examples (a mixture of the liquid composition (A) and the liquid composition (B)) is poured into a predetermined mold and heated in a hot air oven. The temperature was raised from room temperature to 130 ° C. by 1.5 ° C. per minute, held at 130 ° C. for 2 hours, then heated to 180 ° C. by 1.5 ° C. per minute, then 180 ° C. Holding at a temperature of 0 ° C. for 2 hours, a 6 mm thick cured resin plate was produced. The obtained cured resin plate was processed into a test piece shape described in ASTM D5045-99, and then a GIc test was performed in accordance with ASTM D5045-99.

<Manufacture of carbon fiber substrate>
The carbon fiber base material used in the examples was produced as follows. Using carbon fiber T800S-24K-10C (manufactured by Toray Industries, Inc.) for warp and glass fiber ECE225 1/0 1Z (manufactured by Nittobo Co., Ltd.) for wefts, carbon fibers are substantially aligned in one direction. A plain weave fabric was produced. The warp yarn density was 7.2 yarns / 25 mm, and the weft yarn density was 7.5 yarns / 25 mm. The carbon fiber basis weight of the woven fabric was 190 g / m ² .

<Dent depth of fiber reinforced composite material and method for producing CAI specimen>
The fiber reinforced composite material used in the following examples is produced by the RTM molding method. A reinforced fiber base material having a carbon fiber longitudinal direction of 0 ° and repeated three times based on [+ 45 ° / 0 ° / −45 ° / 90 °] is laminated symmetrically to prepare a preform. The resulting preform was injected and impregnated with a two-component curable resin composition for fiber-reinforced composite materials (mixture of liquid composition (A) and liquid composition (B)) at a temperature of 80 ° C. for 1 minute. Then, the temperature is raised to 130 ° C. by 1.5 ° C. and pre-cured at 130 ° C. for 2 hours. After removing the precured product from the RTM mold, it was cured in a hot air oven at a temperature of 180 ° C. for 2 hours to obtain a test specimen.

<Measurement of residual compressive strength (CAI) of fiber reinforced composite material>
From the test body obtained by the above method, a rectangular test piece having a length of 150 mm and a width of 100 mm was cut out with a carbon fiber orientation angle of 0 ° as a longitudinal direction of the test piece, and tested in accordance with JIS K7089 (1996) at the center of the rectangular test piece. After applying a falling weight impact of 20 J per 1 mm thickness, the residual compressive strength (CAI) was measured according to JIS K 7089 (1996).

<Example 1>
A liquid composition (A) and a liquid composition (B) were obtained by the following formulation.

"Liquid composition (A)"
"Celoxide" (registered trademark) 2021P (Daicel Chemical Industries, Ltd., alicyclic epoxy resin): 40 parts-EHPE3150CE (Daicel Chemical Industries, Ltd., alicyclic epoxy resin): 40 parts-Methacrylic acid Methyl: 20 parts “Liquid composition (B)”
"Ancamine" (registered trademark) 2049 (produced by Air Products Japan Co., Ltd., alicyclic amine compound): 33 parts Azobisisobutyronitrile: 0.02 part As a result of measuring the viscosity by the above method, The viscosity of the obtained liquid composition (A) at a temperature of 40 ° C. is 24.0 mPa · s, and the viscosity of the liquid composition (B) at a temperature of 40 ° C. is 33.3 mPa · s. The viscosity at 40 ° C. of a mixture obtained by mixing 33.02 parts of the liquid composition (B) with 100 parts of the product (A) was 31.2 mPa · s.

Moreover, as a result of producing a resin cured product by the above-described method using a mixture and measuring fracture toughness, the fracture toughness (GIc) was 184 J / m ² .
Furthermore, using this two-component curable resin composition for fiber-reinforced composite material, a fiber-reinforced composite material having a volume content of reinforcing fibers of 58.1% and a thickness of 4.43 mm was obtained by the above-described method. The obtained fiber-reinforced composite material was given an impact energy of 20 J per 1 mm thickness of the test piece according to the above method, and the compression strength after impact (CAI) was measured. As a result, it was as high as 207 MPa.

<Example 2>
A liquid composition (A) and a liquid composition (B) were obtained by the following formulation.

"Liquid composition (A)"
"Celoxide" (registered trademark) 2021P (manufactured by Daicel Chemical Industries, Ltd., alicyclic epoxy resin): 40 parts EHPE3150CE (manufactured by Daicel Chemical Industries, Ltd., alicyclic epoxy resin): 40 parts Methyl: 15 parts ・ Glycidyl methacrylate: 5 parts “Liquid composition (B)”
"Ancamine" (registered trademark) 2049 (produced by Air Products Japan Co., Ltd., alicyclic amine compound): 33 parts-BF ₃ -Piperidine (produced by Stella Chemifa Co., Ltd., boron trifluoride piperidine): 3 parts Azobisisobutyronitrile: 0.02 part As a result of measuring the viscosity by the above method, the viscosity of the obtained liquid composition (A) at a temperature of 40 ° C. was 33.3 mPa · s, and the liquid composition ( The viscosity of B) at a temperature of 40 ° C. is 98.1 mPa · s, and the temperature at 40 ° C. of a mixture obtained by mixing 36.02 parts of the liquid composition (B) with 100 parts of the liquid composition (A). The viscosity was 45.4 mPa · s. Moreover, as a result of producing a resin cured product by the above-described method using a mixture and measuring fracture toughness, the fracture toughness (GIc) was 206 J / m ² .

  Furthermore, using this two-component curable resin composition for fiber-reinforced composite material, a fiber-reinforced composite material having a volume content of reinforcing fibers of 58.6% and a thickness of 4.39 mm was obtained by the above-described method. The obtained fiber reinforced composite material was given an impact energy of 20 J per 1 mm thickness of the test piece according to the above method, and the compressive strength after impact (CAI) was measured. As a result, it was as high as 232 MPa.

<Example 3>
A liquid composition (A) and a liquid composition (B) were obtained by the following formulation.

"Liquid composition (A)"
"Celoxide" (registered trademark) 2021P (manufactured by Daicel Chemical Industries, Ltd., alicyclic epoxy resin): 30 parts EHPE3150CE (manufactured by Daicel Chemical Industries, Ltd., alicyclic epoxy resin): 30 parts "(Registered trademark) MY-721 (manufactured by Huntsman Advanced Materials, glycidylamine type epoxy resin): 10 parts" Epicoat "(registered trademark) 828 (manufactured by Japan Epoxy Resin Co., Ltd., bisphenol A type epoxy resin) : 10 parts · Methyl methacrylate: 15 parts · Glycidyl methacrylate: 5 parts "Liquid composition (B)"
"Ancamine" (registered trademark) 2049 (produced by Air Products Japan, alicyclic amine compound): 33.5 parts-"Perocta" (registered trademark) O (produced by Nippon Oil & Fats, Inc., organic peroxide) ): 0.02 part As a result of measuring the viscosity by the above method, the viscosity of the obtained liquid composition (A) at a temperature of 40 ° C. is 40.9 mPa · s, and the liquid composition (B) The viscosity at a temperature of 40 ° C. is 32.1 mPa · s, and the viscosity at a temperature of 40 ° C. of a mixture obtained by mixing 33.52 parts of the liquid composition (B) with 100 parts of the liquid composition (A). Was 38.8 mPa · s. Moreover, as a result of producing a resin cured product by the above method using a mixture and measuring fracture toughness, fracture toughness (GIc) was 192 J / m ² .

  Further, using this two-component curable resin composition for fiber reinforced composite material, a fiber reinforced composite material having a volume content of reinforcing fibers of 58.0% and a thickness of 4.44 mm was obtained by the above-described method. As a result of applying impact energy of 20 J per 1 mm thickness of the test piece to the obtained fiber reinforced composite material according to the above method and measuring the compressive strength after impact (CAI), it was as high as 214 MPa.

<Comparative Example 1>
A liquid composition (A) and a liquid composition (B) were obtained by the following formulation.

"Liquid composition (A)"
"Celoxide" (registered trademark) 2021P (manufactured by Daicel Chemical Industries, Ltd., alicyclic epoxy resin): 50 parts EHPE3150CE (manufactured by Daicel Chemical Industries, Ltd., alicyclic epoxy resin): 50 parts "Liquid composition Things (B) "
"Ancamine" (registered trademark) 2049 (produced by Air Products Japan Co., Ltd., alicyclic amine compound): 41.5 parts-BF ₃ -piperidine (produced by Stella Chemifa Co., Ltd., boron trifluoride piperidine): 3 Part As a result of measuring the viscosity by the above-mentioned method, the viscosity of the obtained liquid composition (A) at a temperature of 40 ° C. is 513 mPa · s, and the viscosity of the liquid composition (B) at a temperature of 40 ° C. is 51 The viscosity at 40 ° C. of a mixture obtained by mixing 44.5 parts of the liquid composition (B) with 100 parts of the liquid composition (A) was 254 mPa · s. Moreover, the resin cured material was produced by the said method using the mixture, and as a result of measuring fracture toughness, fracture toughness (GIc) was 61 J / m < ² >.

  Furthermore, using this two-component curable resin composition for fiber-reinforced composite material, a fiber-reinforced composite material having a volume content of reinforcing fibers of 57.7% and a thickness of 4.46 mm was obtained by the above method. The obtained fiber reinforced composite material was given an impact energy of 20 J per 1 mm thickness of the test piece according to the above method, and the compression strength after impact (CAI) was measured. As a result, the value was as low as 110 MPa.

<Comparative example 2>
A liquid composition (A) and a liquid composition (B) were obtained by the following formulation.

"Liquid composition (A)"
"Celoxide" (registered trademark) 2021P (manufactured by Daicel Chemical Industries, Ltd., alicyclic epoxy resin): 37.5 parts-EHPE3150CE (manufactured by Daicel Chemical Industries, Ltd., alicyclic epoxy resin): 37.5 -"Araldite" (registered trademark) MY-721 (manufactured by Huntsman Advanced Materials, glycidylamine type epoxy resin): 12.5 parts-"Epicoat" 828 (manufactured by Japan Epoxy Resins Co., Ltd., bisphenol A type epoxy) Resin): 12.5 parts “Liquid Composition (B)”
"Ancamine" (registered trademark) 2049 (manufactured by Air Products Japan Co., Ltd., alicyclic amine compound): 41.5 parts As a result of measuring the viscosity by the above method, the liquid composition (A) obtained The viscosity at 40 ° C. is 853 mPa · s, the viscosity of the liquid composition (B) at 40 ° C. is 30.0 mPa · s, and the liquid composition (B) is added to 100 parts of the liquid composition (A). The viscosity of the mixture obtained by mixing 41.5 parts at 40 ° C. was 271 mPa · s. Moreover, as a result of producing a resin cured product by the above-described method using the mixture and measuring fracture toughness, the fracture toughness (GIc) was 58 J / m ² .

  Further, using this two-component curable resin composition for fiber reinforced composite material, a fiber reinforced composite material having a volume content of reinforcing fibers of 57.8% and a thickness of 4.45 mm was obtained by the above-described method. According to the above method, the obtained fiber reinforced composite material was given an impact energy of 20 J per 1 mm thickness of the test piece, and the compressive strength after impact (CAI) was measured.

  The fiber reinforced composite material using the two-component curable resin composition for fiber reinforced composite material of the present invention can be suitably used for structural materials such as aircraft, spacecraft, railway vehicles, automobiles and ships. It is useful because it can be applied to the fields of leisure industries such as tennis rackets, golf shafts and fishing rods, and architecture.

Claims (10)

  A liquid composition (A) having a viscosity of not more than 500 mPa · s containing an alicyclic epoxy resin (A1) and a methacrylic acid ester compound (A2), an aliphatic polyamine compound (B1), and a radical are generated by heating. It consists of a liquid composition (B) containing a radical polymerization initiator (B2) and having a viscosity at 40 ° C. of 500 mPa · s or less, and heat-curing by mixing the liquid composition (A) and the liquid composition (B) Possible two-component curable resin composition for fiber-reinforced composite materials.   The methacrylic acid ester compound (A2) is blended in an amount of 1 to 40% by weight in the liquid composition (A), the two-component curable resin composition for fiber-reinforced composite materials according to claim 1.   The fiber-reinforced composite material according to claim 1 or 2, wherein the methacrylic acid ester compound (A2) contains 1 to 20% by weight of a compound having an unsaturated group and one or more functional groups. Two-component curable resin composition.   The two-component curable resin composition for fiber-reinforced composite materials according to claim 3, wherein the compound having an unsaturated group and one or more functional groups is glycidyl methacrylate.   The fiber reinforcement according to any one of claims 1 to 4, wherein an initial viscosity at 40 ° C of a mixture obtained by mixing the liquid composition (A) and the liquid composition (B) is 500 mPa · s or less. Two-component curable resin composition for composite materials. The fracture toughness (GIc) of a cured product obtained by heating and curing a mixture of the liquid composition (A) and the liquid composition (B) at a temperature of 180 ° C. for 2 hours is 150 J / m ² or more. The two-component curable resin composition for fiber-reinforced composite materials according to any one of claims 1 to 5.   A fiber reinforced composite material comprising a resin cured product of the two-component curable resin composition for fiber reinforced composite materials according to any one of claims 1 to 6 and reinforcing fibers.   The fiber-reinforced composite material according to claim 7, wherein the reinforcing fiber is a carbon fiber.   The fiber-reinforced composite material according to claim 7 or 8, wherein the volume content of the reinforcing fibers is 50 to 65%.   A two-part curable resin composition for a fiber-reinforced composite material according to any one of claims 1 to 6 is injected and impregnated into a woven fabric including reinforcing fibers arranged in a mold, and then cured by heating. A method for producing a fiber-reinforced composite material.