JP2010202727A - Epoxy resin composition for fiber-reinforced composite material and fiber-reinforced composite material using the same - Google Patents

Abstract

An epoxy resin composition having a high elastic modulus, a high heat resistance and a high toughness as a matrix resin for a fiber reinforced composite material, and a high tensile strength and a high adhesion to carbon fiber as a fiber reinforced composite material. I will provide a.
A fiber-reinforced composite material comprising, as an essential component, an epoxy resin having at least one of component (A) colloidal dispersion type nanosilica fine particles, component (B) heterocyclic structure, and condensed cyclic structure. An epoxy resin composition is used.
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Description

  The present invention relates to an epoxy resin composition for fiber reinforced composite materials and a fiber reinforced composite material using the same. In particular, the present invention provides an epoxy resin composition for obtaining a fiber-reinforced composite material suitable for use in automotive applications, marine applications, sports applications, and other general industrial applications, including aircraft structural materials, and the use thereof. Prepreg and fiber reinforced composite material.

  Carbon fiber reinforced composite materials composed of carbon fibers and matrix resin cured products are widely used in aircraft, automobiles, and industrial applications because of their excellent mechanical properties. In recent years, the application range of carbon fiber reinforced composite materials has been expanded more and more as the use results are accumulated. As the matrix resin constituting such a composite material, a thermosetting resin excellent in impregnation and heat resistance is often used, and the thermosetting resin is excellent in moldability and is highly sophisticated even in a high temperature environment. It is necessary to develop mechanical strength. As such a thermosetting resin, phenol resin, melamine resin, bismaleimide resin, unsaturated polyester resin, epoxy resin, etc. are used, among which epoxy resin is excellent in heat resistance and moldability, carbon Since a high mechanical strength can be obtained when a fiber composite material is used, it is widely used.

  In the conventional carbon fiber reinforced composite material, the tensile strength in the fiber direction is good, but the carbon fiber is fibrous and the fiber diameter is extremely small. Therefore, when compressed in the fiber direction, the fiber buckling and / or shearing occurs. Therefore, the fiber is easily broken, and there is a strong demand for improving the compressive strength of the fiber-reinforced composite material. For this reason, attempts have been made to improve the elastic modulus of the matrix resin in order to suppress fiber breakage due to fiber buckling and / or shear and to improve compressive strength.

  It is also known that it is effective to increase the heat resistance of the matrix resin in order to develop high mechanical strength in the fiber reinforced composite material in a high temperature environment. In order to increase the heat resistance of the matrix resin, it is necessary to increase the crosslink density. However, if the crosslink density is increased, the elastic modulus of the resin is improved to a certain level, but if the crosslink density is too high, the cured resin is increased. It is known that the free volume inside increases and the elastic modulus of the resin does not easily increase. For this reason, it has been considered that it is very difficult to achieve both the high elastic modulus and heat resistance of the matrix resin.

  However, Patent Document 1 discloses a prepreg and a fiber-reinforced composite material, which are made of an epoxy resin and are excellent in compression system mechanical properties. However, in the resin composition of Patent Document 1, it cannot be said that the elastic modulus of the matrix resin is still sufficient, and the toughness of the resin is low, so that there is a problem that the tensile strength becomes low when processed into a composite material. . Therefore, further improvement in elastic modulus and toughness of the matrix resin is desired.

  Patent Document 2 discloses a prepreg and a fiber-reinforced composite material that exhibit high mechanical strength not only under room temperature drying but also in a moist heat environment, using a resin composition mainly composed of a benzoxazine resin as a matrix. Has been. However, the resin composition of Patent Document 2 has a problem that the adhesion between the carbon fiber and the matrix resin is weak.

JP-A-8-259713 JP 2006-233188 A

  The present invention provides an epoxy resin composition that exhibits high elastic modulus, high heat resistance, and high toughness as a matrix resin for fiber reinforced composite materials, and also exhibits high tensile strength and high adhesion to carbon fibers as a fiber reinforced composite material. The purpose is to provide goods.

  As a result of intensive studies to solve the above problems, the present inventors have found that the problems can be solved by an epoxy resin composition having the following configuration. Therefore, this invention consists of the following matters.

1) An epoxy resin composition for fiber-reinforced composite materials comprising the following components (A) and (B) as essential constituent elements.
Component (A) Colloidal dispersion type nano silica fine particle Component (B) Epoxy resin having at least one of a heterocyclic structure and a condensed cyclic structure

2) The epoxy resin composition according to 1) above, which contains an epoxy resin having at least one selected from an oxadizolidone ring and a xanthene skeleton as a heterocyclic structure.

3) The epoxy resin composition as described in 1) above, which contains an epoxy resin having at least one selected from a naphthalene skeleton and a dicyclopentadiene skeleton as a condensed cyclic structure.

4) The epoxy resin composition according to 1) above, which contains a bifunctional naphthalene type epoxy resin as the component (B).

5) The epoxy resin composition according to any one of 1) to 4) above, which comprises 2 to 40 parts by mass of the component (A) and 5 to 90 parts by mass of the component (B) with respect to 100 parts by mass of the epoxy resin component.

6) The above-mentioned 1) to 5) containing 2 to 30 parts by mass of a component (C) monofunctional epoxy resin or a bifunctional or lower epoxy resin having one benzene ring in the molecule with respect to 100 parts by mass of the epoxy resin component The epoxy resin composition in any one.

7) The epoxy resin composition according to any one of 1) to 6) above, which contains 3,3′-diaminodiphenylsulfone as a curing agent.

8) A prepreg comprising the epoxy resin composition according to any one of 1) to 7) and a reinforcing fiber.

9) A fiber-reinforced composite material obtained by curing the prepreg described in 8) above.

  According to the present invention, as a matrix resin for a fiber-reinforced composite material, an epoxy that exhibits a high elastic modulus, high heat resistance, and high toughness, and also exhibits high tensile strength and high adhesion to carbon fibers as a fiber-reinforced composite material. A resin composition can be obtained.

  Hereinafter, preferred embodiments of the present invention will be described. However, the present invention is not limited to these embodiments, and it is understood that various modifications can be made within the spirit and scope of the present invention. I want.

  The component (A) used in the present invention is colloidally dispersed nano silica fine particles. Colloidal dispersion type nano silica fine particles are silica fine particles dispersed without aggregation of nano silica fine particles in a liquid such as epoxy resin by the action of surface charge. The compounding amount of the colloidally dispersed nano silica fine particles is preferably 2 to 40 parts by mass with respect to 100 parts by mass of the epoxy resin component. If the blending amount of the colloidal dispersion-type nanosilica fine particles is 2 parts by mass or more with respect to 100 parts by mass of the epoxy resin component, the elastic modulus of the epoxy resin composition can be increased. More preferably, it is 5 parts by mass or more, more preferably 10 parts by mass or more, and still more preferably 15 parts by mass or more. On the other hand, when the blending amount of the colloidally dispersed nano silica fine particles is increased, it may be difficult to maintain a good dispersion state in the epoxy resin. The dispersibility of the silica fine particles in the epoxy resin can be maintained by setting the amount of the colloidally dispersed nanosilica fine particles to 40 parts by mass or less with respect to 100 parts by mass of the epoxy resin component. More preferably, it is 25 parts by mass or less.

  It is preferable that the colloidal dispersion type nanosilica fine particles have a particle size of 100 nm or less because the toughness of the epoxy resin composition can be increased. More preferably, it is 50 nm or less. The particle size of the colloidal dispersion-type nanosilica particles can be measured by observing the cross section of the cured product of the epoxy resin composition with an electron microscope such as SEM or TEM.

  As a method for blending and dispersing colloidal dispersion type nanosilica fine particles in an epoxy resin, an epoxy resin in which commercially available colloidal dispersion type nanosilica fine particles are blended may be blended in the epoxy resin composition. As an epoxy resin in which such colloidal dispersion type nano silica fine particles are blended, Nanopox series manufactured by Nanoresin Co., Nanopox F400, Nanopox F430, Nanopox F440, Nanopox F520, Nanopox F640, Nanopox F640, Nanopox F640, Nanopox F640, Nanopox F640, Nanopox F640, Nanopox F640, Nanopox F640, Nanopox F640, Nanopox F640 Examples include E440, Nanopox E520, Nanopox E630, Nanopox E640, and LENANOC E as a LENANOC series manufactured by Nissan Chemical Industries, but any nano silica fine particles dispersed in an epoxy resin may be used. It is not limited.

  Component (B) used in the present invention is an epoxy resin having at least one structure out of a heterocyclic structure and a condensed cyclic structure. By incorporating an epoxy resin having such a skeleton into the crosslinked structure of the cured product, the toughness of the cured product can be increased.

  It is preferable that the compounding quantity of a component (B) is 5-90 mass parts with respect to 100 mass parts of epoxy resin components. If the compounding quantity of a component (B) is 5 mass parts or more with respect to 100 mass parts of epoxy resin components, the toughness of an epoxy resin composition can be improved. More preferably, it is 10 mass parts or more, More preferably, it is 15 mass parts or more, More preferably, it is 20 mass parts or more. On the other hand, if the amount of component (B) is increased, the heat resistance and elongation at break of the cured product may be reduced. By making the compounding quantity of a component (B) 90 mass parts or less with respect to 100 mass parts of epoxy resin components, it becomes difficult to reduce the heat resistance and breaking elongation of hardened | cured material. More preferably, it is 80 parts by mass or less.

  The heterocyclic structure is preferably at least one selected from an oxazolidone skeleton and a xanthene skeleton. Examples of the epoxy resin having a heterocyclic structure include AER4151 and AER4152 made by Asahi Kasei Epoxy Co., Ltd. as an epoxy resin having an oxazolidone skeleton, and EXA- made by DIC Corporation as an epoxy resin having a xanthene skeleton. 7335, EXA-7336, EXA-7337, and the like, but are not limited thereto.

  The condensed cyclic structure is preferably at least one selected from a naphthalene skeleton, a dicyclopentadiene skeleton, and a fluorene skeleton. Examples of the epoxy resin having a condensed cyclic structure include, for example, Epicron HP4032, EXA-4700 manufactured by DIC Corporation as an epoxy resin having a naphthalene skeleton, EX1257 manufactured by Tohto Kasei Co., and SHELL as an epoxy resin having a fluorene skeleton. Examples thereof include EPON (registered trademark) HPT1079 manufactured by the company, but are not limited thereto.

  Among the heterocyclic structures and condensed ring structures described above, when an epoxy resin having a naphthalene skeleton, a dicyclopentadiene skeleton, or an oxazolidone skeleton is used in combination with colloidally dispersed nanosilica fine particles, the tensile strength, compressive strength, It is preferable because of its excellent adhesive strength. As the epoxy resin having a naphthalene skeleton, an epoxy resin having a bifunctional naphthalene skeleton is particularly preferable.

  The component (C) used in the present invention is a monofunctional epoxy resin or a bifunctional or lower epoxy resin having one benzene ring in the molecule. By incorporating an epoxy resin having such a skeleton into the crosslinked structure of the cured product, the elastic modulus of the cured product can be increased.

  It is preferable that the compounding quantity of a component (C) is 2-30 mass parts with respect to 100 mass parts of epoxy resin components. If the compounding amount of the monofunctional epoxy resin or the bifunctional or lower epoxy resin having one cyclic skeleton in the molecule is 2 parts by mass or more with respect to 100 parts by mass of the epoxy resin component, the elasticity of the epoxy resin composition The rate can be increased. More preferably, it is 5 parts by mass or more, more preferably 10 parts by mass or more, and still more preferably 15 parts by mass or more. On the other hand, when the amount of the monofunctional epoxy resin or the bifunctional or lower epoxy resin having one benzene ring in the molecule is increased, the heat resistance, elongation at break and toughness of the cured product may be lowered. By setting the blending amount of monofunctional epoxy resin or bifunctional or lower epoxy resin having one benzene ring in the molecule to 30 parts by mass or less with respect to 100 parts by mass of the epoxy resin component, the heat resistance and fracture of the cured product Elongation and toughness are difficult to decrease. More preferably, it is 25 parts by mass or less.

  Monofunctional epoxy resins include glycidyl ether type, glycidyl ester type, and alicyclic type epoxy resins, but may be epoxy resins having one epoxy group in the molecule excluding the cyclohexene oxide structure, and are not limited thereto. It is not a thing. In particular, an epoxy resin having a cyclic skeleton such as an imide ring, a benzene ring, a naphthalene skeleton, a biphenyl skeleton, an anthracene skeleton, or a benzoquinone skeleton in the molecule is preferable because the elastic modulus of the cured product can be increased. Examples of such monofunctional epoxy resins include phenyl glycidyl ether, cresyl glycidyl ether, cardanol glycidyl ether, styrene oxide, phenylphenyl glycidyl ether, and glycidyl phthalimide. The bifunctional or lower epoxy resin having one benzene ring in the molecule is an epoxy resin having one benzene ring structure in the molecule and two or less epoxy groups excluding the cyclohexene oxide structure in the molecule. Especially, the epoxy resin represented by the following formula 1 is particularly preferable because it has a high effect of increasing the elastic modulus of the cured product and has good heat resistance.

(In the above formula, R ^{1 to} R ⁵ each independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 8 carbon atoms)
Moreover, the epoxy resin represented by the following formula 2 is preferable because it has a very high effect of increasing the elastic modulus of the cured product.

  As the curing agent for the epoxy resin composition of the present invention, amines, acid anhydrides, phenols, mercaptans, Lewis acid amine complexes, onium salts, imidazoles, and the like can be used as long as they can cure the epoxy resin. Any structure may be used. Of these, amine type curing agents are preferred. Examples of amine-type curing agents include aromatic amines such as diaminodiphenylmethane and diaminodiphenylsulfone, aliphatic amines, imidazole derivatives, dicyandiamide, tetramethylguanidine, thiourea-added amines, and isomers and modified products thereof. Can be used. Among these, dicyandiamide is particularly preferable because it has excellent prepreg storage stability. Further, various isomers of diaminodiphenylsulfone are particularly suitable for the present invention because they give a cured product having good heat resistance. For example, it is preferable to use 4,4'-diaminodiphenylsulfone because the heat resistance of the cured product can be increased and the tack life of the prepreg can be maintained for a long period. Although 3,3′-diaminodiphenylsulfone is inferior to 4,4′-diaminodiphenylsulfone in the prepreg tack life and the heat resistance of the cured product, it is preferable because the elastic modulus of the cured product can be very high. . Further, it is preferable to add 4,4'-diaminodiphenylsulfone and 3,3'-diaminodiphenylsulfone at the same time because the heat resistance and elastic modulus of the cured product can be easily adjusted.

  These curing agents can be combined with an appropriate curing aid in order to increase the curing activity. Preferred examples include dicyandiamide and 3-phenyl-1,1-dimethylurea, 3- (3,4-dichlorophenyl) -1,1-dimethylurea (DCMU), 3- (3-chloro-4-methylphenyl). Examples of combining urea derivatives such as -1,1-dimethylurea and 2,4-bis (3,3-dimethylureido) toluene as curing aids, tertiary amines for carboxylic anhydrides and novolak resins As an example, a combination of diaminodiphenylsulfone with an urea complex such as imidazole compound or phenyldimethylurea (PDMU), an amine complex such as monoethylamine trifluoride or an amine trichloride complex as a curing aid.

  Moreover, 1 or more types of resin chosen from the group which consists of a thermoplastic resin, a thermoplastic elastomer, and an elastomer can be added to the epoxy resin composition of this invention as an additive. This additive has the role of improving the toughness of the matrix resin and changing the viscoelasticity to optimize the viscosity, storage elastic modulus and thixotropic properties. The thermoplastic resin, thermoplastic elastomer or elastomer used as the additive may be used alone or in combination of two or more. The thermoplastic resin, thermoplastic elastomer or elastomer may be blended by being dissolved in the epoxy resin component, and the surface layer of the prepreg in the form of fine particles, long fibers, short fibers, woven fabric, nonwoven fabric, mesh, pulp, etc. May be arranged. Thereby, delamination of the fiber reinforced composite material can be suppressed.

  The thermoplastic resin includes a group consisting of a carbon-carbon bond, amide bond, imide bond, ester bond, ether bond, carbonate bond, urethane bond, urea bond, thioether bond, sulfone bond, imidazole bond and carbonyl bond in the main chain. A thermoplastic resin having a bond selected from is preferably used.

  Examples of the thermoplastic resin include a group of thermoplastic resins belonging to engineering plastics such as polyacrylate, polyamide, polyaramid, polyester, polycarbonate, polyphenylene sulfide, polybenzimidazole, polyimide, polyetherimide, polysulfone and polyethersulfone. More preferably used. From the viewpoint of excellent heat resistance, polyimide, polyetherimide, polysulfone, polyethersulfone and the like are particularly preferably used. Moreover, it is preferable that these thermoplastic resins have a functional group reactive with the thermosetting resin from the viewpoint of improving toughness and maintaining the environmental resistance of the cured resin. Particularly preferred functional groups include a carboxyl group, an amino group, and a hydroxyl group.

  A fiber-reinforced composite material can be obtained by impregnating a reinforcing fiber with the epoxy resin composition of the present invention and curing it by heating.

  There is no restriction on the reinforcing fiber combined with the epoxy resin composition of the present invention, and carbon fiber, graphite fiber, glass fiber, organic fiber, boron fiber, steel fiber, etc. are used in the form of tow, cloth, chopped fiber, mat, etc. can do.

  Among these reinforcing fibers, carbon fibers and graphite fibers are preferable in the present invention because they have good specific elastic modulus and a great effect on weight reduction. Also, any type of carbon fiber or graphite fiber can be used depending on the application.

  In addition, there are no restrictions on the use of the fiber reinforced composite material, and it can be used for general-purpose products such as tennis rackets and golf shafts. However, the fiber reinforced composite material using the epoxy resin composition of the present invention has excellent compressive strength in the fiber direction. Therefore, it is most suitable for use in aircraft parts.

  Fiber reinforced composite materials can be produced by processing into a sheet-like molding intermediate called prepreg, molding methods such as autoclave molding, sheet wrap molding, and press molding, and epoxy resin composition for reinforcing fiber filaments and preforms. Molding methods such as RTM, VaRTM, filament winding, and RFI that directly impregnate a product to obtain a molded product can be used, but are not limited to these molding methods.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited at all by these Examples.

Preparation of Resin Composition Each raw material excluding the curing agent component and wet silica fine particles was weighed into a glass flask and heated and mixed at 150 ° C. to obtain a uniform epoxy resin main agent and benzoxazine resin composition. Next, after cooling the obtained epoxy resin main agent to 70 ° C. or less, the curing agent component (and wet silica fine particles as required) is weighed and added, and uniformly dispersed by heating and mixing at 70 ° C., An epoxy resin composition was obtained.

Preparation of heat-cured resin plate The obtained epoxy resin composition and benzoxazine resin composition were injected between two glass plates (2 mm thickness and 3 mm thickness) with a polytetrafluoroethylene spacer sandwiched between 2 mm thickness. And cured at 180 ° C. for 2 hours to obtain a resin plate.

Measurement of flexural modulus of resin plate The obtained 2 mm thick resin plate was processed into a test piece (length 60 mm x width 8 mm x thickness 2 mm), and a three-point bending jig (3.2 mmR for both indenter and support, distance between supports) 32 mm) was used to measure the bending characteristics in an environment of a temperature of 23 ° C. and a humidity of 50% RH. The loading speed was 2 mm / min.

Measurement of heat resistance The obtained resin plate having a thickness of 2 mm was processed into a test piece (length 55 mm × width 12.5 mm × thickness 2 mm), and measured using a rheometer ARES-RDA manufactured by TA Instruments, with a measurement frequency of 1 Hz, Log G ′ is plotted against temperature at a heating rate of 5 ° C./min, and the temperature at the intersection of the approximate straight line of the flat region of log G ′ and the approximate straight line of the region where G ′ transitions is expressed as the glass transition temperature (G ′ Recorded as Tg).

Measurement of GIc A GIc test was conducted as an evaluation index of resin toughness. The 3 mm thick resin plate obtained above was processed into a shape of 32 mm long x 3 mm wide x 7 mm thick and 3.5 mm notch with a wet diamond cutter, and then cracked at the notch tip by a slide method using a degreased razor. To form a test piece. The obtained test piece was tested according to ASTM D-5045 to obtain GIc. The test was carried out using a universal testing machine manufactured by Instron, the indenter and the support having R = 5.0, and the test was carried out in an environment with a support distance of 28 mm, a temperature of 23 ° C., and a humidity of 50% RH. The loading speed was 10 mm / min.

Method for Producing Prepreg Using a comma coater, an epoxy resin composition and a benzoxazine resin composition were uniformly applied on one side of a release paper with a basis weight of 49 g / m ² to obtain a resin-carrying sheet. Using a double film type prepreg machine, pulling carbon fibers with a tensile strength of 5500 MPa and a tensile modulus of elasticity: 360 GPa, and sandwiching them between the two resin-carrying sheets, heating them with a heating roll to impregnate the carbon fibers A prepreg having 190 g / m ² and a resin content of 34% by mass was obtained.

Measurement of 0 ° Tensile Strength of Laminated Composite Material Unidirectional prepreg produced by the method described above is aligned in fiber direction, laminated in 6 plies, and heated in an autoclave at 180 ° C for 2 hours under 0.7 MPa pressure. A laminated composite material was produced by molding at 1.7 ° C./min. About this laminated composite material, 90 degree tensile strength was calculated | required according to SACMA 4R-94 in the environment of temperature 23 degreeC and humidity 50% RH. The tensile strength was measured for six samples, and a converted value with a fiber content of 60% was calculated, and the average was obtained as 0 ° compressive strength.

Measurement of 90 ° tensile strength of laminated composite material The unidirectional prepreg produced by the method described above is aligned in the fiber direction, laminated in 12 plies, and heated in an autoclave at 180 ° C for 2 hours under a pressure of 0.7 MPa. A laminated composite material was produced by molding at 1.7 ° C./min. About this laminated composite material, 90 degree tensile strength was calculated | required according to SACMA 4R-94 in the environment of temperature 23 degreeC and humidity 50% RH. Such tensile strength was measured on six samples.

Measurement of 0 ° Compressive Strength of Laminated Composite Material Unidirectional prepreg produced by the method described above is aligned in fiber direction, 6 plies are laminated, and heated at 180 ° C. for 2 hours at 0.7 MPa under a pressure of 0.7 MPa. A laminated composite material was produced by molding at 1.7 ° C./min. About this laminated composite, 0 degree compressive strength was calculated | required according to SACMA 1R-94 in the environment of temperature 23 degreeC and humidity 50% RH. The compressive strength was measured for six samples, and a converted value with a fiber content of 60% was calculated, and the average was obtained as 0 ° compressive strength.

Examples 1-10 and Comparative Examples 1-14
As described above, an epoxy resin composition and a benzoxazine resin composition comprising the raw material composition shown in Table 1 (the amount of each component is in parts by mass) are prepared, and then a cured resin plate is prepared and cured. The physical properties of the resin plate were measured. Table 2 shows the evaluation results of the physical properties of the components contained in the epoxy resin composition and the benzoxazine resin composition (the amount of each component is part by mass) and the cured resin plate.

Details of the raw materials used for the blending are shown below.
Nanopox E430: Nanosilica fine particle-blended epoxy resin in which nanosilica fine particles are colloidally dispersed in an epoxy resin, 60% of the component is a bisphenol type epoxy resin (bifunctional), and 40% of the component is a colloidally dispersed nanosilica fine particle masterbatch type epoxy resin An average particle diameter of nano silica fine particles 20 nm, manufactured by Nanoresin, HP4032: bifunctional naphthalene type epoxy resin, manufactured by DIC, HP7200: dicyclopentadiene type epoxy resin, manufactured by DIC, AER4152: oxazodidoridone ring type epoxy resin, manufactured by Asahi Kasei GAN: Glycidyl aniline, Nippon Kayaku Co., Ltd. Celoxide 3000: Epoxy resin having cyclohexene oxide group, Daicel Chemical Industries, Ltd. JER604: Tetraglycidyl diaminodiphenylmethane type epoxy tree Fat, Japan Epoxy Resin EPPN502H: Triphenylmethane novolak epoxy resin, Nippon Kayaku MY-0600: Metaaminophenol epoxy resin, Huntsman NC-7300L: Naphthalene novolac epoxy resin, Nippon Kayaku Co., Ltd. Manufactured ELM-100: Paraaminocresol type epoxy resin, Huntsman JER828: Bisphenol A type epoxy resin, Japan Epoxy Resin JER807: Bisphenol F type epoxy resin, Japan Epoxy Resin JER1009: Bisphenol A type epoxy resin, Japan Epoxy EXA1514 manufactured by Resin Co., Ltd .: Bisphenol S type epoxy resin, manufactured by DIC, Fa type benzoxazine: Fa type benzoxazine resin, Shikoku Kasei Co., Ltd. UFP-80: Type silica fine particles, average particle size of silica fine particles 34 nm, manufactured by Denki Kagaku Co., Ltd. 3,3′-DDS: 3,3′-diaminodiphenyl sulfone, manufactured by Nippon Synthetic Chemical Industry Co., Ltd. PES-5003P: polyethersulfone, thermoplastic resin, Sumitomo Made by Chemical

  As can be seen from Tables 1 and 2, the cured resin plates obtained in the examples each have a very high elastic modulus, heat resistance and toughness at the same time, and the laminated composite material produced from the obtained resin is The 0 ° tensile strength, 90 ° tensile strength, and 0 ° compressive strength all showed high values.

  On the other hand, since the comparative example does not contain both the component (A) and the component (B), the obtained cured resin plate cannot exhibit high values in terms of elastic modulus, heat resistance and toughness at the same time, and is a laminated composite material. Also in the physical properties, low values were shown in any of 0 ° tensile strength, 90 ° tensile strength, and 0 ° compressive strength.

  As described in detail above, the epoxy resin composition for a prepreg of the present invention has high elastic modulus, heat resistance, and toughness of the matrix itself after curing, and the fiber-reinforced composite material obtained from the epoxy resin composition is High values were shown in all of 0 ° tensile strength, 90 ° tensile strength, and 0 ° compressive strength. Therefore, the present invention is industrially useful.

Claims (9)

An epoxy resin composition for fiber-reinforced composite materials, comprising the following components (A) and (B) as essential constituent elements.
Component (A) Colloidal dispersion type nano silica fine particle Component (B) Epoxy resin having at least one of a heterocyclic structure and a condensed cyclic structure   The epoxy resin composition of Claim 1 containing the epoxy resin which has at least 1 sort (s) chosen from an oxazizolidone ring and a xanthene skeleton as a heterocyclic structure.   The epoxy resin composition according to claim 1, comprising an epoxy resin having at least one selected from a naphthalene skeleton and a dicyclopentadiene skeleton as a condensed cyclic structure.   The epoxy resin composition according to claim 1, comprising a bifunctional naphthalene type epoxy resin as the component (B).   The epoxy resin composition according to any one of claims 1 to 4, comprising 2 to 40 parts by mass of the component (A) and 5 to 90 parts by mass of the component (B) with respect to 100 parts by mass of the epoxy resin component.   In any one of Claims 1-5 containing 2-30 mass parts of component (C) monofunctional epoxy resin or bifunctional or less epoxy resin which has one benzene ring in a molecule | numerator with respect to 100 mass parts of epoxy resin components. The epoxy resin composition as described.   The epoxy resin composition according to any one of claims 1 to 6, comprising 3,3'-diaminodiphenylsulfone as a curing agent.   A prepreg comprising the epoxy resin composition according to claim 1 and reinforcing fibers.   A fiber-reinforced composite material obtained by curing the prepreg according to claim 8.