EPOXY RESIN COMPOSITION FOR RESIN TRANSFER MOLDING, CURED RESIN PRODUCT, FIBER-REINFORCED COMPOSITE MATERIAL, AND METHOD FOR MANUFACTURING SAME

Abstract

An object is to provide an epoxy resin composition for resin transfer molding (RTM) having a low viscosity and low volatility and excellent in balance among elastic modulus at the time of wet heating, heat resistance at the time of wetting, and fracture toughness of a cured resin of the epoxy resin composition, and to provide a large fiber-reinforced composite material having a high Vf and including the epoxy resin composition. An epoxy resin composition for RTM including a component [A], a component [B], and a component [C] described below: [A] a tetrafunctional glycidyl amine type epoxy resin, [B] at least one aromatic amine curing agent selected from the group consisting of an alkylbenzenediamine and a methylenebisaniline, [C] an aniline type epoxy resin represented by Formula (I):

##STR00001## wherein R.sup.1 and R.sup.2 each represent at least one selected from aliphatic hydrocarbon groups having a carbon number of 1 or more and 4 or less, in a case where a plurality of R's are present, the plurality of R's are identical or different, in a case where a plurality of R.sup.2s are present, the plurality of R.sup.2s are identical or different, n is an integer of 0 or more and 4 or less, m is an integer of 0 or more and 5 or less, and X represents O or S, the epoxy resin composition for RTM satisfying all of Condition 1 to Condition 4 described below: Condition 1: in the epoxy resin composition for RTM, a viscosity at 110 C. is 1 mPa.Math.s or more and 200 mPa.Math.s or less, Condition 2: in the epoxy resin composition for RTM, a mass reduction rate after heating the epoxy resin composition for RTM at 110 C. for 30 minutes is 0.3 mass % or less, Condition 3: a cured resin obtained by curing the epoxy resin composition for RTM at 180 C. for 2 hours has a rubbery state elastic modulus of 2 MPa or more and 8 MPa or less, Condition 4: a cured resin obtained by curing the epoxy resin composition for RTM at 180 C. for 2 hours has a water absorption coefficient of 1% or more and 3% or less.

Claims

1. An epoxy resin composition for resin transfer molding (RTM) comprising a component [A], a component [B], and a component [C] described below: [A] a tetrafunctional glycidyl amine type epoxy resin, [B] at least one aromatic amine curing agent selected from the group consisting of an alkylbenzenediamine and a methylenebisaniline, [C] an aniline type epoxy resin represented by Formula (I): ##STR00003## wherein R.sup.1 and R.sup.2 each represent at least one selected from aliphatic hydrocarbon groups having a carbon number of 1 or more and 4 or less, in a case where a plurality of R.sup.1s are present, the plurality of R.sup.1s are identical or different, in a case where a plurality of R.sup.2s are present, the plurality of R.sup.2s are identical or different, n is an integer of 0 or more and 4 or less, m is an integer of 0 or more and 5 or less, and X represents O or S, the epoxy resin composition for RTM satisfying all of Condition 1 to Condition 4 described below: Condition 1: in the epoxy resin composition for RTM, a viscosity at 110 C. is 1 mPa s or more and 200 mPa s or less, Condition 2: in the epoxy resin composition for RTM, a mass reduction rate after heating the epoxy resin composition for RTM at 110 C. for 30 minutes is 0.3 mass % or less, Condition 3: a cured resin obtained by curing the epoxy resin composition for RTM at 180 C. for 2 hours has a rubbery state elastic modulus of 2 MPa or more and 8 MPa or less, Condition 4: a cured resin obtained by curing the epoxy resin composition for RTM at 180 C. for 2 hours has a water absorption coefficient of 1% or more and 3% or less.

2. The epoxy resin composition for RTM according to claim 1, wherein the component [C] is included in an amount of 10 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of a total epoxy resin.

3. The epoxy resin composition for RTM according to claim 1, comprising a core-shell type rubber particle as a component [D] in an amount of 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the total epoxy resin.

4. The epoxy resin composition for RTM according to claim 1, comprising at least one solid epoxy resin as a component [E] in an amount of 10 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the total epoxy resin, the at least one solid epoxy resin selected from the group consisting of dicyclopentadiene type epoxy resins, biphenyl type epoxy resins, phenol aralkyl type epoxy resins, and naphthalene type epoxy resins.

5. The epoxy resin composition for RTM according to claim 1, comprising both an alkylbenzenediamine and a methylenebisaniline as the component [B].

6. The epoxy resin composition for RTM according to claim 1, wherein the component [B] is an alkylbenzenediamine.

7. The epoxy resin composition for RTM according to claim 1, comprising dimethylthiotoluenediamine as the alkylbenzenediamine.

8. The epoxy resin composition for RTM according to claim 1, comprising 4,4-methylenebis(isopropyl-6-methylaniline) as the methylenebisaniline.

9. The epoxy resin composition for RTM according to claim 1, having a value (Mh/Me) of 0.8 or more and 1.1 or less, the value (Mh/Me) obtained by dividing Mh representing a sum of moles of active hydrogen contained in the component [B] by Me representing a sum of moles of active groups contained in the total epoxy resin.

10. A cured resin obtained by thermally curing the epoxy resin composition for RTM according to claim 1.

11. A fiber-reinforced composite material comprising the cured resin according to claim 10 and a reinforcing-fiber base material.

12. The fiber-reinforced composite material according to claim 11, wherein the reinforcing-fiber base material is a carbon fiber base material.

13. A method for producing a fiber-reinforced composite material, the method comprising: injecting the epoxy resin composition for RTM according to claim 1 into a reinforcing-fiber base material disposed in a mold heated to 70 C. or more and 190 C. or less; impregnating the epoxy resin composition for RTM into the reinforcing-fiber base material; and curing the epoxy resin composition for RTM in the mold.

14. The method for producing a fiber-reinforced composite material according to claim 13, wherein the reinforcing-fiber base material is a carbon fiber base material.

Description

EXAMPLES

[0106] Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to the description in Examples.

[0107] The materials, the method of preparing samples and the like, and the evaluation method used in the present Examples are as follows.

Materials Used

[0108] (1) Component [A]: Tetrafunctional glycidyl amine type epoxy resin [0109] [A]-1 SUMI-EPOXY (registered trademark) ELM434VL (manufactured by SUMITOMO CHEMICAL COMPANY, LIMITED, epoxy equivalent weight: 115 g/eq), [0110] [A]-2 Araldite (registered trademark) MY721 (manufactured by Huntsman Japan KK., epoxy equivalent weight: 115 g/eq), [A]-3 SUMI-EPOXY (registered trademark) ELM434 (manufactured by SUMITOMO CHEMICAL COMPANY, LIMITED, epoxy equivalent weight: 120 g/eq). [0111] (2) Component [B]: At least one aromatic amine curing agent selected from the group consisting of an alkylbenzenediamine and a methylenebisaniline, [0112] (2-1) Alkylbenzenediamine [0113] [B]-1: jERcure (registered trademark) WA (manufactured by Mitsubishi Chemical Corporation, active hydrogen equivalent weight: 45 g/eq), [0114] [B]-2: Ethacure (registered trademark) 300 (manufactured by Albemarle Corporation, active hydrogen equivalent weight: 54 g/eq), [0115] (2-2) Methylenebisaniline [0116] [B]-3: Lonzacure (registered trademark) M-MIPA (manufactured by Lonza K.K., active hydrogen equivalent weight: 78 g/eq), [0117] [B]-4: Lonzacure (registered trademark) M-CDEA (manufactured by Lonza K.K., active hydrogen equivalent weight: 95 g/eq). [0118] (3) Component [D]: Mixture of core-shell type rubber particle and component [A] or component [F] [0119] [D]-1 Kane Ace (registered trademark) MX-416 (75 mass % of glycidyl amine type epoxy resin (corresponding to component [A]) and 25 mass % of butadiene-based core-shell type rubber particle, epoxy equivalent weight: 148 g/eq), [0120] [D]-2 Kane Ace (registered trademark) MX-267 (63 mass % of bisphenol F type epoxy resin (corresponding to component [F]) and 37 mass % of butadiene-based core-shell type rubber particle, epoxy equivalent weight: 270 g/eq) (all manufactured by KANEKA CORPORATION). [0121] (4) Component [C]: Glycidylaniline type epoxy resin represented by Formula (I) [0122] TOREP (registered trademark) A-204E (manufactured by Toray Fine Chemicals Co., Ltd., epoxy equivalent weight: 162 g/eq). [0123] (5) Component [E]: At least one solid epoxy resin selected from the group consisting of dicyclopentadiene type epoxy resins, biphenyl type epoxy resins, phenol aralkyl type epoxy resins, and naphthalene type epoxy resins [0124] (5-1) Dicyclopentadiene type epoxy resin [0125] [E]-1 EPICLON (registered trademark) HP-7200L (manufactured by DIC Corporation, epoxy equivalent weight: 246 g/eq), [0126] [E]-2 EPICLON (registered trademark) HP-7200H (manufactured by DIC Corporation, epoxy equivalent weight: 278 g/eq), [0127] (5-2) Biphenyl type epoxy resin [0128] [E]-3 jER (registered trademark) YX-4000 (manufactured by Mitsubishi Chemical Corporation, epoxy equivalent weight: 186 g/eq), [0129] (5-3) Phenol aralkyl type epoxy resin [0130] [E]-4 NC-3000L (manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent weight: 272 g/eq). [0131] (6) Component [F]: Another epoxy resin [0132] [F]-1 GAN (manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent weight: 125 g/eq), [0133] [F]-2 jER (registered trademark) 828 (manufactured by Mitsubishi Chemical Corporation, epoxy equivalent weight: 189 g/eq), [0134] [F]-3 EPICLON (registered trademark) 830 (manufactured by DIC Corporation, epoxy equivalent weight: 171 g/eq), [0135] [F]-4 jER (registered trademark) 630 (manufactured by Mitsubishi Chemical Corporation, epoxy equivalent weight: 98 g/eq). [0136] (7) Another curing agent component [0137] [G]-1: SEIKACURE (registered trademark) S (manufactured by Wakayama Seika Kogyo Co., Ltd., active hydrogen equivalent weight: 62 g/eq).

<Method of Preparing Epoxy Resin Composition for RTM>

[0138] Predetermined amounts of components other than a component [B] and another curing agent component were put into a stainless steel beaker, heated to a temperature of 60 to 150 C., and appropriately kneaded until the components were compatible to obtain an epoxy main agent liquid.

[0139] The component [B] and another curing agent component were added into another container, and heated as necessary to be compatible, and thus a curing agent liquid was obtained.

[0140] Predetermined amounts of the epoxy main agent liquid and the curing agent liquid were mixed at about 60 C. and kneaded with a planetary mixer for 3 minutes to obtain an epoxy resin composition for RTM. The composition is as shown in Tables 1 to 4.

<Method of Preparing Fiber-Reinforced Composite Material>

(1) Preparation of Reinforcing-Fiber Base Material with Nonwoven Fabric

[0141] A nonwoven fabric (fiber areal weight: 6 g/m.sup.2) including polyamide 12 was attached to one surface of a plain woven fabric (fiber areal weight: 285 g/m.sup.2) including a carbon fiber Torayca (registered trademark) T700G-12K-31E as a reinforcing fiber. Then, the nonwoven fabric was fused using a far-infrared heater to obtain a reinforcing-fiber base material with a nonwoven fabric in which the nonwoven fabric is provided on one surface of the reinforcing-fiber base material.

(2) Preparation of Fiber-Reinforced Composite Material

[0142] The reinforcing-fiber base material with a nonwoven fabric obtained in accordance with (1) Preparation of Reinforcing-Fiber Base Material with Nonwoven Fabric described above was cut into 400 mm400 mm so as to have fiber directions of 0/90 and 45/45. The reinforcing-fiber base material with a nonwoven fabric cut out into a mold was laminated in a configuration of [(45/45)/(0/90)]4s. Subsequently, the mold was heated to 110 C., and the epoxy resin composition obtained in accordance with <Method of Preparing Epoxy Resin Composition> described above was separately heated to 110 C. in advance and injected into the mold. Thereafter, the temperature was raised to 180 C. at a rate of 1.5 C./min, and the epoxy resin composition was cured at 180 C. for 2 hours to obtain a fiber-reinforced composite material.

Evaluation Methods

[0143] Hereinafter, the evaluation method in Examples will be described. In the evaluation method, description of the number of times of measurement is omitted in a case where the number n is 1.

(1) Method of Evaluating Viscosity of Epoxy Resin Composition for RTM at 110 C. (.SUB.0.)

[0144] The epoxy resin composition for RTM obtained in accordance with <Method of Preparing Epoxy Resin Composition for RTM> described above was set in the following device within 5 minutes after mixing on a parallel plate set at 110 C. so that the gap was 1.0 mm, measurement was started under the following conditions, and the complex viscosity when the temperature of the epoxy resin composition for RTM reached 110 C. was regarded as .sub.0. [0145] Measurement device: Dynamic viscoelasticity measurement device (Discovery HR-2, manufactured by TA Instruments) [0146] Measurement mode: Parallel plate (25 mm, gap: 1.0 mm) [0147] Shear speed: 100s.sup.1 [0148] Set temperature: 110 C.

(2) Method of Evaluating Mass Reduction Rate of Epoxy Resin Composition for RTM at 110 C.

[0149] About 2 g of the epoxy resin composition for RTM obtained in accordance with <Method of Preparing Epoxy Resin Composition for RTM> described above was put into an aluminum cup having an inner diameter of 50 mm, weighed with an electronic balance, then heated in a blower oven (DKM400, manufactured by Yamato Scientific Co., Ltd.) set at 110 C., taken out after 30 minutes, cooled to normal temperature, and then weighed again, and the mass reduction rate of the resin was calculated. The number of samples was n=5, and the average of the samples was adopted as the mass reduction rate value.

(3) Method of Evaluating Flexural Modulus (23 C., 50% RH): E.SUB.23 .of Cured Resin

[0150] The epoxy resin composition for RTM obtained in accordance with <Method of Preparing Epoxy Resin Composition for RTM> described above was defoamed in vacuum, and then cured at a temperature of 180 C. for 2 hours in a mold set to have a thickness of 2 mm with a 2 mm thick TEFLON (registered trademark) spacer, and thus a plate-shaped cured resin having a thickness of 2 mm was obtained. From the cured resin, a test piece having a width of 10 mm and a length of 60 mm was cut out, 3-point bending was performed using an Instron universal testing machine (manufactured by Instron) with a span of 32 mm at a crosshead speed of 10 mm/min in accordance with JIS K7171 (1994) under a room temperature environment (23 C., 50% RH), and thus the flexural modulus (23 C., 50% RH) was measured. The number of samples was n=6, and the average of these samples was adopted as the flexural modulus value.

(4) Method of Evaluating Flexural Modulus (82 C. Under Wet Condition): E.SUB.82 .and Water Absorption Coefficient of Cured Resin

[0151] A cured resin was obtained in the same manner as in (3) Method of Evaluating Flexural Modulus (23 C., 50% RH): E.sub.23 of Cured Resin described above, and a test piece having a width of 10 mm and a length of 60 mm was cut out, and then immersed in boiling water for 48 hours. The taken-out test piece was subjected to 3-point bending using an Instron universal testing machine (manufactured by Instron) with a span of 32 mm at a crosshead speed of 10 mm/min in accordance with JIS K7171 (1994) under a high temperature environment (82 C.), and thus the flexural modulus (82 C. under wet condition) was measured. The mass of the test piece was measured before and after the immersion in boiling water for 48 hours, and the water absorption coefficient was calculated from the difference in mass. The number of samples was n=6, and the average of these samples was adopted as the flexural modulus value.

(5) Method of Evaluating Glass Transition Temperature (Dry Tg) of Cured Resin

[0152] The epoxy resin composition for RTM obtained in accordance with <Method of Preparing Epoxy Resin Composition for RTM> described above was defoamed in an uncured state in vacuum, and then cured at a temperature of 180 C. for 2 hours in a mold set to have a thickness of 2 mm with a 2 mm thick TEFLON (registered trademark) spacer, and thus a plate-shaped cured resin having a thickness of 2 mm was obtained. From the cured resin, a test piece having a width of 12.7 mm and a length of 45 mm was cut out and set on a solid twisting jig at an inter-chunk distance of 30 mm, the test piece was set on the solid twisting jig, and measurement was performed using a dynamic viscoelasticity measurement device (ARES-G2, manufactured by TA Instruments) at a temperature ramp rate of 5 C./min, a frequency of 1 Hz, and a strain amount of 0.08% in a temperature range of 40 to 260 C. At this time, in the obtained graph of the storage modulus and the temperature, the temperature at the intersection of the tangent line drawn in the glass region and the tangent line drawn in the glass transition temperature region was regarded as the glass transition temperature (dry Tg). In the obtained graph of the storage modulus and the temperature, the storage modulus at a temperature higher than the glass transition temperature by 50 C. was regarded as the rubbery state elastic modulus.

(6) Method of Evaluating Glass Transition Temperature (Wet Tg) of Cured Resin

[0153] A cured resin was obtained in the same manner as in (5) Method of Evaluating Glass Transition Temperature (Dry Tg) of Cured Resin described above, and a test piece having a width of 12.7 mm and a length of 45 mm was cut out, and then immersed in boiling water for 48 hours. The viscoelasticity was measured in the same manner as in <Method of Evaluating Glass Transition Temperature (Dry Tg) of Cured Resin described above, and thus the glass transition temperature (wet Tg) was obtained.

(7) Method of Evaluating Fracture Toughness Value of Cured Resin

[0154] The epoxy resin composition for RTM obtained in accordance with <Method of Preparing Epoxy Resin Composition for RTM> described above was defoamed in vacuum, and then cured at a temperature of 180 C. for 2 hours in a mold set to have a thickness of 6 mm with a 6 mm thick TEFLON (registered trademark) spacer, and thus a plate-shaped cured resin having a thickness of 6 mm was obtained. The obtained cured resin was processed into a test piece shape described in ASTM D5045-99, and then subjected to an SENB test in accordance with ASTM D5045-99. The number of samples was n=16, and the average of the samples was adopted as the fracture toughness value Klc value.

(8) Method of Evaluating Open Hole Compression (23 C., 50% RH): OHC.SUB.23 .of Fiber-Reinforced Composite Material

[0155] From the fiber-reinforced composite material obtained in accordance with <Preparation of Fiber-Reinforced Composite Material> described above, a rectangular piece having a length of 304.8 mm in the 0 direction and 38.1 mm in the 90 direction was cut out, and a circular hole having a diameter of 6.35 mm was bored in the piece at the center to obtain a test piece. The open hole compression (23 C., 50% RH) of this test piece was measured using an Instron universal testing machine (manufactured by Instron) in accordance with ASTM-D6484 under a room temperature environment (23 C., 50% RH). The number of samples was n=5, and the average of the samples was adopted as the OHC.sub.23 value.

(9) Method of Evaluating Open Hole Compression (82 C. under wet condition): OHC.sub.82 of Fiber-Reinforced Composite Material

[0156] A test piece was obtained in the same manner as in (8) Method of Evaluating Open Hole Compression (23 C., 50% RH) of Fiber-Reinforced Composite Material described above. This test piece was immersed in hot water at 72 C. for 14 days, and then the open hole compression (82 C. under wet condition) was measured using an Instron universal testing machine (manufactured by Instron) in accordance with ASTM-D6484 under a high temperature environment (82 C.). The number of samples was n=5, and the average of the samples was adopted as the OHC.sub.82 value.

(10) Method of Evaluating Compression Strength after Impact (CAI) of Fiber-Reinforced Composite Material

[0157] From the fiber-reinforced composite material obtained in accordance with <Preparation of Fiber-Reinforced Composite Material> described above, a rectangular piece having a length of 150 mm in the 0 direction and 100 mm in the 90 direction was cut out to obtain a test piece. For this test piece, a falling water impact of 6.7 J/mm was applied to the center of the test piece in accordance with JIS K7089 (1996), and the compression strength after impact was measured using an Instron universal testing machine (manufactured by Instron) in accordance with JIS K7089 (1996). The number of samples was n=5, and the average of the samples was adopted as the CAI value.

[0158] Hereinafter, the method of preparing a sample, the cured resin properties, and the measurement results of the uncured resin properties in each Example will be described.

Example 1

[0159] An epoxy resin composition for RTM was prepared in accordance with <Method of Preparing Epoxy Resin Composition for RTM> described above using, as an epoxy resin, 25 parts by mass of SUMI-EPOXY (registered trademark) ELM-434VL (component [A]), 30 parts by mass of TOREP (registered trademark) A-204E (component [C]), 30 parts by mass of EPICLON (registered trademark) HP-7200H (component [E]), 20 parts by mass of Kane Ace (registered trademark) MX-416 (5 parts by mass of component [D] and 15 parts by mass of component [A]), 9.5 parts by mass of jERcure (registered trademark) WA (component [B]), and 28.4 parts by mass of Lonzacure (registered trademark) M-MIPA (component [B]).

[0160] The flexural property of this epoxy resin composition for RTM was acquired in accordance with (3) Method of Evaluating Flexural Modulus (23 C., 50% RH): E.sub.23 of Cured Resin and (4) Method of Evaluating Flexural Modulus (82 C. under wet condition): E.sub.82 and Water Absorption Coefficient of Cured Resin described above. As a result, E.sub.23 was 3.75 GPa, E.sub.82 was 3.20 GPa, and E.sub.82/E.sub.23 was 0.85, showing an excellent elastic modulus under wet heating. The heat resistance was evaluated in accordance with (5) Method of Evaluating Glass Transition Temperature (Dry Tg) of Cured Resin and (6) Method of Evaluating Glass Transition Temperature (Wet Tg) of Cured Resin described above. As a result, dry Tg was 178 C., wet Tg was 170 C., and wet Tg/dry Tg was 0.96, showing excellent heat resistance. In addition, a very good water absorption coefficient of 1.7% was exhibited, and the rubbery state elastic modulus was 4.2 MPa. The fracture toughness value was evaluated in accordance with (7) Method of Evaluating Fracture Toughness Value of Cured Resin described above. As a result, a good fracture toughness value of 1.2 MPa.Math.m.sup.0.5 was exhibited.

[0161] As for the viscosity, no was evaluated in accordance with (1) Method of Evaluating Viscosity of Epoxy Resin Composition for RTM at 110 C. (.sub.0) described above. As a result, no was 40 mPa.Math.s. The mass reduction rate was evaluated in accordance with (2) Method of Evaluating Mass Reduction Rate of Epoxy Resin Composition for RTM at 110 C. described above. As a result, the mass reduction rate was 0.12 mass %.

Examples 2 to 21

[0162] Epoxy resin compositions for RTM and cured resins were prepared in the same manner as in Example 1 except that the resin composition was changed as shown in Tables 1 to 3.

[0163] As a result of evaluating the elastic modulus under wet heating and the elastic modulus at room temperature, wet Tg and dry Tg, the water absorption coefficient, and the fracture toughness value of the epoxy resin composition for RTM of each Example, good physical properties were obtained at all levels. In each Example, .sub.0 was within a range of 18 mPa.Math.s or more and 50 mPa.Math.s or less, the mass reduction rate was within a range of 0.07 mass % or more and 0.20 mass % or less, and the rubbery state elastic modulus was within a range of 3.5 MPa or more and 8.0 MPa or less.

Comparative Example 1

[0164] For the resin composition shown in Table 4, an epoxy resin composition for RTM was prepared with the method described in Example 2 of Patent Document 1 (Japanese Patent No. 5808057). The curing agent (M-CDEA) of the epoxy resin composition was solid.

[0165] The flexural property of this epoxy resin composition for RTM was acquired in accordance with (3) Method of Evaluating Flexural Modulus (23 C., 50% RH): E.sub.23 of Cured Resin and (4) Method of Evaluating Flexural Modulus (82 C. under wet condition): E.sub.82 and Water Absorption Coefficient of Cured Resin described above. As a result, E.sub.23 was as high as 3.80 GPa, but E.sub.82 was 2.60 GPa and thus was remarkably low, and E.sub.82/E.sub.23 was 0.68. The heat resistance was evaluated in accordance with (5) Method of Evaluating Glass Transition Temperature (Dry Tg) of Cured Resin and (6) Method of Evaluating Glass Transition Temperature (Wet Tg) of Cured Resin described above. As a result, dry Tg was 175 C., wet Tg was 155 C., and wet Tg/dry Tg was 0.89. Thus, the heat resistance deteriorated significantly after wetting, and the water absorption coefficient was as high as 3.0%. The fracture toughness value was evaluated in accordance with (7) Method of Evaluating Fracture Toughness Value of Cured Resin described above. As a result, an insufficient fracture toughness value of 0.9 MPa.Math.m.sup.0.5 was exhibited. The rubbery state elastic modulus was 10.0 MPa and thus was out of the range. .sub.0 was 50 mPa.Math.s, and the mass reduction rate was 0.22 mass %.

Comparative Example 2

[0166] For the resin composition shown in Table 4, an epoxy resin composition for RTM was prepared with the method described in Example 26 of Patent Document 2 (International Publication No. 2021-241734).

[0167] For the epoxy resin composition, E.sub.82 and E.sub.23, wet Tg and dry Tg, the water absorption coefficient, the fracture toughness value, the rubbery state elastic modulus, no, and the mass reduction rate were evaluated in the same manner as in Example 1.

[0168] The epoxy resin composition included the component [A] and the component [B], but did not include the component [C], and instead included a bisphenol F type epoxy resin, which was another epoxy resin, and TGpAP. E.sub.82 was as low as 2.40 GPa, and E.sub.82/E.sub.23 was 0.71, showing a large decrease in elastic modulus after wetting. Dry Tg was 184 C., wet Tg was 160 C., and thus wet Tg/dry Tg was 0.87, showing a large decrease in heat resistance after wetting, and the water absorption coefficient was as high as 2.8%. In addition, an insufficient fracture toughness value of 0.8 MPa.Math.m.sup.0.5 was exhibited. The rubbery state elastic modulus was 12.0 MPa and thus was out of the range.

Comparative Example 3

[0169] For the resin composition shown in Table 4, an epoxy resin composition for RTM was prepared with the method described in Example 24 of Patent Document 2 (Japanese Patent Laid-open Publication No. 2010-150310).

[0170] For the epoxy resin composition, E.sub.82 and E.sub.23, wet Tg and dry Tg, the water absorption coefficient, the fracture toughness value, the rubbery state elastic modulus, .sub.0, and the mass reduction rate were evaluated in the same manner as in Example 1.

[0171] The epoxy resin composition included the component [A] and the component [B], but did not include the component [C]. E.sub.82 was as low as 2.40 GPa, and E.sub.82/E.sub.23 was 0.73, showing a large decrease in elastic modulus after wetting. Dry Tg was 182 C., wet Tg was 158 C., and thus wet Tg/dry Tg was 0.87, showing a large decrease in heat resistance after wetting, and the water absorption coefficient was as high as 2.7%. In addition, an insufficient fracture toughness value of 0.9 MPa.Math.m.sup.05 was exhibited. The rubbery state elastic modulus was 10.1 MPa and thus was out of the range.

Comparative Example 4

[0172] For the resin composition shown in Table 4, an epoxy resin composition for RTM was prepared in the same manner as in Example 1, and E.sub.82 and E.sub.23, wet Tg and dry Tg, the water absorption coefficient, the fracture toughness value, the rubbery state elastic modulus, .sub.0, and the mass reduction rate were evaluated.

[0173] The epoxy resin composition did not include the component [C] but instead included glycidylaniline, which had a low molecular weight. Therefore, the mass reduction rate was 0.41 mass % and thus was out of the range.

Comparative Example 5

[0174] For the resin composition shown in Table 4, an epoxy resin composition for RTM was prepared with the method described in Example 3 of Patent Document 4 (International Publication No. 2010-109929).

[0175] For the epoxy resin composition, E.sub.82 and E.sub.23, wet Tg and dry Tg, the water absorption coefficient, the fracture toughness value, the rubbery state elastic modulus, .sub.0, and the mass reduction rate were evaluated in the same manner as in Example 1.

[0176] The epoxy resin composition did not include the component [B] but instead included 4,4-diaminodiphenyl sulfone, which had high polarity. Therefore, .sub.0 was 230 mPa.Math.s and thus was out of the range, and the water absorption coefficient of the cured resin was 3.5% and thus was also out of the range.

Comparative Example 6

[0177] For the resin composition shown in Table 4, an epoxy resin composition for RTM was prepared in the same manner as in Example 1, and E.sub.82 and E.sub.23, wet Tg and dry Tg, the water absorption coefficient, the fracture toughness value, the rubbery state elastic modulus, .sub.0, and the mass reduction rate were evaluated.

[0178] The epoxy resin composition did not include the component [A] and instead included jER (registered trademark) 630, and therefore the rubbery state elastic modulus was 10.0 MPa and thus was out of the range. The epoxy resin composition had a low elastic modulus at the time of wet heating and low heat resistance at the time of wetting, and the water absorption coefficient was as high as 2.7%. In addition, an insufficient fracture toughness value of 0.8 MPa.Math.m.sup.0.5 was exhibited.

Comparative Example 7

[0179] For the resin composition shown in Table 4, an epoxy resin composition for RTM was prepared in the same manner as in Example 1, and E.sub.82 and E.sub.23, wet Tg and dry Tg, the water absorption coefficient, the fracture toughness value, the rubbery state elastic modulus, .sub.0, and the mass reduction rate were evaluated.

[0180] The epoxy resin composition did not include the component [C] and instead included EPICLON (registered trademark) 830, and therefore the rubbery state elastic modulus was 9.8 MPa and thus was out of the range. The fracture toughness value was 0.8 MPa.Math.m.sup.0.5 and thus was insufficient. In addition, an insufficient elastic modulus at the time of wet heating of 2.40 GPa was exhibited.

TABLE-US-00001 TABLE 1-1 Raw materials of epoxy resin composition Example 1 Example 2 Example 3 Example 4 Example 5 Component [A]: SUMI-EPOXY.sup. ELM-434VL Tetraglycidyl 25 25 25 65 55 tetrafunctional glycidyl Araldite MY721 diaminodiphenylmethane amine type epoxy resin SUMI-EPOXY ELM434 Component [C]: TOREP.sup. A-204E Diglycidyl-p- 30 30 30 20 30 glycidylaniline type epoxy phenoxyaniline resin represented by Formula (I) Component [E]: at least one EPICLON.sup. HP-7200L Dicyclopentadiene solid epoxy resin selected EPICLON.sup. HP-7200H type epoxy resin 30 30 30 from the group consisting jER.sup. YX-4000 Biphenyl type epoxy of dicyclopentadiene type resin epoxy resins, biphenyl type NC-3000L Phenol aralkyl type epoxy resins, phenol epoxy resin aralkyl type epoxy resins, and naphthalene type epoxy resins Component [F]: another GAN Glycidylaniline epoxy resin jER.sup. 828 Bisphenol A type epoxy resin EPICLON.sup. 830 Bisphenol F type epoxy resin jER.sup. 630 Triglycidyl-p- aminophenol Mixture of core-shell Kane Ace MX-416 [D]: core-shell type 5 5 5 5 5 type rubber particle and Masterbatch containing rubber particle epoxy resin 25 mass % of core shell Tetrafunctional 15 15 15 15 15 rubber particles glycidyl amine type epoxy resin (component [A]) Mixture of core-shell Kane Ace MX-267 [D]: core-shell type type rubber particle and Masterbatch containing rubber particle epoxy resin 37 mass % of core shell Bisphenol F type rubber particles epoxy resin (component [F]) Component [B]: at least jERcure WA Diethyltoluenediamine 9.5 16.4 21.6 17.3 16.8 one aromatic amine Ethacure.sup. 300 Dimethylthiotoluene curing agent selected diamine from alkylbenzenediamine Lonzacure.sup. M-MIPA 4,4-Methylenebis(2- 28.4 16.4 7.2 33.6 32.6 and methylenebisaniline isopropyl-6- methylaniline) Lonzacure.sup. M-CDEA 4,4-Methylenebis (3- chloro-2,6- diethylaniline) Another curing agent SEIKACURE S 4,4-Diaminodiphenyl sulfone Mh/Me 0.90 0.90 0.90 1.00 1.00 Properties of cured Flexural modulus (23 C., GPa 3.75 3.60 3.50 3.70 3.75 resin 50% RH): E.sub.23 Flexural modulus (under wet GPa 3.20 3.00 2.90 2.90 2.90 heating at 82 C.): E.sub.82 E.sub.82/E.sub.23 0.85 0.83 0.83 0.78 0.77 Dry Tg C. 178 181 184 197 186 Wet Tg C. 170 170 170 176 167 Wet Tg/dry Tg 0.96 0.94 0.92 0.89 0.90 Rubbery state elastic MPa 4.2 6.4 7.2 8.0 6.8 modulus Water absorption % 1.7 2.0 2.2 2.5 2.4 coefficient K1c MPa .Math. m.sup.0.5 1.2 1.0 1.0 1.0 1.0 Properties of uncured Mass reduction rate after mass % 0.12 0.16 0.20 0.18 0.17 resin 30 minutes at 110 C. Viscosity at 110 C.: .sub.0 mPa .Math. s 40 31 25 24 22

TABLE-US-00002 TABLE 1-2 Example Example Example Raw materials of epoxy resin composition 6 7 8 Component [A]: SUMI-EPOXY ELM- Tetraglycidyl 45 64 43 tetrafunctional glycidyl 434VL diaminodiphenylmethane amine type epoxy resin Araldite MY721 SUMI-EPOXY ELM434 Component [C]: TOREP A-204E Diglycidyl-p- 40 30 30 glycidylaniline type epoxy phenoxyaniline resin represented by Formula (I) Component [E]: at least one EPICLON HP-7200L Dicyclopentadiene solid epoxy resin selected EPICLON HP-7200H type epoxy resin from the group consisting jER YX-4000 Biphenyl type epoxy of dicyclopentadiene type resin epoxy resins, biphenyl type NC-3000L Phenol aralkyl type epoxy resins, phenol epoxy resin aralkyl type epoxy resins, and naphthalene type epoxy resins Component [F]: another GAN Glycidylaniline epoxy resin jER B28 Bisphenol A type epoxy resin EPICLON B30 Bisphenol F type epoxy resin jER 630 Triglycidyl-p- aminophenol Mixture of core-shell Kane Ace MX-416 [D]: core-shell type 5 2 9 type rubber particle and Masterbatch containing rubber particle epoxy resin 25 mass % of core shell Tetrafunctional 15 6 27 rubber particles glycidyl amine type epoxy resin (component [A]) Mixture of core-shell Kane Ace MX-267 [D]: core-shell type type rubber particle and Masterbatch containing rubber particle epoxy resin 37 mass % of core shell Bisphenol F type rubber particles epoxy resin (component [F]) Component [B]: at least jERcure WA Diethyltoluenediamine 16.2 16.7 16.9 one aromatic amine Ethacure 300 Dimethylthiotoluene curing agent selected diamine from alkylbenzenediamine Lonzacure M-MIPA 4,4-Methylenebis(2- 31.5 32.4 32.7 and methylenebisaniline isopropyl-6- methylaniline) Lonzacure M-CDEA 4,4-Methylenebis(3- chloro-2,6- diethylaniline) Another curing agent SEIKACURE S 4,4-Diaminodiphenyl sulfone Mh/Me 1.00 1.00 1.00 Properties of cured Flexural modulus (23 C., GPa 3.80 3.85 3.60 resin 50% RH): E.sub.23 Flexural modulus (under wet GPa 2.95 3.00 2.90 heating at 82 C.): E.sub.82 E.sub.82/E.sub.23 0.78 0.78 0.81 Dry Tg C. 178 185 186 Wet Tg C. 159 166 168 Wet Tg/dry Tg 0.89 0.90 0.90 Rubbery state elastic MPa 4.9 6.9 7.0 modulus Water absorption % 2.5 2.4 2.4 coefficient K1c MPa .Math. m.sup.0.5 1.1 0.9 1.4 Properties of uncured Mass reduction rate after mass % 0.16 0.16 0.15 resin 30 minutes at 110 C. Viscosity at 110 C.: .sub.0 mPa .Math. s 18 20 34

TABLE-US-00003 TABLE 2-1 Example Example Example Example Raw materials of epoxy resin composition 9 10 11 12 Component [A]: SUMI-EPOXY.sup. ELM-434VL Tetraglycidyl 50 25 25 25 tetrafunctional glycidyl Araldite MY721 diaminodiphenylmethane amine type epoxy resin SUMI-EPOXY ELM434 Component [C]: TOREP.sup. A-204E Diglycidyl-p- 20 20 30 30 glycidylaniline type epoxy phenoxyaniline resin represented by Formula (I) Component [E]: at least one EPICLON.sup. HP-7200L Dicyclopentadiene 15 40 solid epoxy resin selected EPICLON.sup. HP-7200H type epoxy resin 30 30 from the group consisting jER.sup. YX-4000 Biphenyl type epoxy of dicyclopentadiene type resin epoxy resins, biphenyl type NC-3000L Phenol aralkyl type epoxy resins, phenol epoxy resin aralkyl type epoxy resins, and naphthalene type epoxy resins Component [F]: another GAN Glycidylaniline epoxy resin jER.sup. 828 Bisphenol A type epoxy resin EPICLON.sup. 830 Bisphenol F type epoxy resin jER.sup. 630 Triglycidyl-p- aminophenol Mixture of core-shell Kane Ace MX-416 [D]: core-shell type 5 5 5 5 type rubber particle and Masterbatch containing rubber particle epoxy resin 25 mass % of core shell Tetrafunctional 15 15 15 15 rubber particles glycidyl amine type epoxy resin (component [A]) Mixture of core-shell Kane Ace MX-267 [D]: core-shell type type rubber particle and Masterbatch containing rubber particle epoxy resin 37 mass % of core shell Bisphenol F type rubber particles epoxy resin (component [F]) Component [B]: at least jERcure WA Diethyltoluenediamine 14.3 12.1 10.8 16.3 one aromatic amine Ethacure.sup. 300 Dimethylthiotoluene curing agent selected diamine from alkylbenzenediamine Lonzacure.sup. M-MIPA 4,4-Methylenebis(2- 27.7 23.5 21.0 31.6 and methylenebisaniline isopropyl-6- methylaniline) Lonzacure.sup. M-CDEA 4,4-Methylenebis (3- chloro-2,6- diethylaniline) Another curing agent SEIKACURE S 4,4-Diaminodiphenyl sulfone Mh/Me 0.90 0.90 0.80 1.20 Properties of cured Flexural modulus (23 C., GPa 3.60 3.30 3.60 3.90 resin 50% RH): E.sub.23 Flexural modulus (under wet GPa 3.00 2.90 2.95 3.00 heating at 82 C.): E.sub.82 E.sub.82/E.sub.23 0.83 0.88 0.82 0.77 Dry Tg C. 190 184 170 167 Wet Tg C. 173 175 155 152 Wet Tg/dry Tg 0.91 0.95 0.91 0.91 Rubbery state elastic MPa 8.0 6.2 4.2 4.1 modulus Water absorption % 2.3 1.7 2.1 2.2 coefficient K1c MPa .Math. m.sup.0.5 1.0 1.2 1.0 1.0 Properties of uncured Mass reduction rate after mass % 0.14 0.13 0.10 0.16 resin 30 minutes at 110 C. Viscosity at 110 C.: .sub.0 mPa .Math. s 29 47 41 38

TABLE-US-00004 TABLE 2-2 Example Example Example Raw materials of epoxy resin composition 13 14 15 Component [A]: SUMI-EPOXY ELM- Tetraglycidyl 25 25 25 tetrafunctional glycidyl 434VL diaminodiphenylmethane amine type epoxy resin Araldite MY721 SUMI-EPOXY ELM434 Component [C]: TOREP A-204E Diglycidyl-p- 30 30 30 glycidylaniline type epoxy phenoxyaniline resin represented by Formula (I) Component [E]: at least one EPICLON HP-7200L Dicyclopentadiene 10 10 solid epoxy resin selected EPICLON HP-7200H type epoxy resin 30 from the group consisting jER YX-4000 Biphenyl type epoxy 20 of dicyclopentadiene type resin epoxy resins, biphenyl type NC-3000L Phenol aralkyl type 20 epoxy resins, phenol epoxy resin aralkyl type epoxy resins, and naphthalene type epoxy resins Component [F]: another GAN Glycidylaniline epoxy resin jER 828 Bisphenol A type epoxy resin EPICLON 830 Bisphenol F type epoxy resin jER 630 Triglycidyl-p- aminophenol Mixture of core-shell Kane Ace MX-416 [D]: core-shell type 5 5 5 type rubber particle and Masterbatch containing rubber particle epoxy resin 25 mass % of core shell Tetrafunctional 15 15 15 rubber particles glycidyl amine type epoxy resin (component [A]) Mixture of core-shell Kane Ace MX-267 [D]: core-shell type type rubber particle and Masterbatch containing rubber particle epoxy resin 37 mass % of core shell Bisphenol F type rubber particles epoxy resin (component [F]) Component [B]: at least jERcure WA Diethyltoluenediamine 13.0 12.3 one aromatic amine Ethacure 300 Dimethylthiotoluene curing agent selected diamine from alkylbenzenediamine Lonzacure M-MIPA 4,4-Methylenebis(2- 25.2 23.9 44.9 and methylenebisaniline isopropyl-6- methylaniline) Lonzacure M-CDEA 4,4-Methylenebis(3- chloro-2,6- diethylaniline) Another curing agent SEIKACURE S 4,4-Diaminodiphenyl sulfone Mh/Me 0.90 0.90 0.90 Properties of cured Flexural modulus (23 C., GPa 3.90 3.85 3.85 resin 50% RH): E.sub.23 Flexural modulus (under wet GPa 3.15 3.15 3.20 heating at 82 C.): E.sub.82 E.sub.82/E.sub.23 0.81 0.82 0.83 Dry Tg C. 173 175 175 Wet Tg C. 166 165 164 Wet Tg/dry Tg 0.96 0.94 0.94 Rubbery state elastic MPa 5.0 5.5 3.5 modulus Water absorption % 1.8 1.7 1.5 coefficient K1c MPa .Math. m.sup.0.5 1.1 1.2 1.3 Properties of uncured Mass reduction rate after mass % 0.14 0.13 0.07 resin 30 minutes at 110 C. Viscosity at 110 C.: .sub.0 mPa .Math. s 34 30 50

TABLE-US-00005 TABLE 3 Example Example Example Example Example Example Raw materials of epoxy resin composition 16 17 18 19 20 21 Component [A]: SUMI-EPOXY.sup. ELM-434VL Tetraglycidyl 40 40 40 25 40 25 tetrafunctional glycidyl Araldite MY721 diaminodiphenylmethane amine type epoxy resin SUMI-EPOXY ELM434 Component [C]: TOREP.sup. A-204E Diglycidyl-p- 20 20 20 30 30 30 glycidylaniline type epoxy phenoxyaniline resin represented by Formula (I) Component [E]: at least one EPICLON.sup. HP-7200L Dicyclopentadiene 25 10 10 solid epoxy resin selected EPICLON.sup. HP-7200H type epoxy resin 30 30 30 from the group consisting jER.sup. YX-4000 Biphenyl type epoxy 15 of dicyclopentadiene type resin epoxy resins, biphenyl type NC-3000L Phenol aralkyl type 15 epoxy resins, phenol epoxy resin aralkyl type epoxy resins, and naphthalene type epoxy resins Component [F]: another GAN Glycidylaniline epoxy resin jER.sup. 828 Bisphenol A type epoxy resin EPICLON.sup. 830 Bisphenol F type epoxy resin jER.sup. 630 Triglycidyl-p- aminophenol Mixture of core-shell Kane Ace MX-416 [D]: core-shell type 5 5 5 5 5 type rubber particle and Masterbatch containing rubber particle epoxy resin 25 mass % of core shell Tetrafunctional 15 15 15 15 15 rubber particles glycidyl amine type epoxy resin (component [A]) Mixture of core-shell Kane Ace MX-267 [D]: core-shell type type rubber particle and Masterbatch containing rubber particle epoxy resin 37 mass % of core shell Bisphenol F type rubber particles epoxy resin (component [F]) Component [B]: at least jERcure WA Diethyltoluenediamine 7.2 one aromatic amine Ethacure.sup. 300 Dimethylthiotoluene 41.6 42.7 41.2 22.8 22.8 25.7 curing agent selected diamine from alkylbenzenediamine Lonzacure.sup. M-MIPA 4,4-Methylenebis(2- 21.9 21.9 and methylenebisaniline isopropyl-6- methylaniline) Lonzacure.sup. M-CDEA 4,4-Methylenebis (3- chloro-2,6- diethylaniline) Another curing agent SEIKACURE S 4,4-Diaminodiphenyl sulfone Mh/Me 1.10 1.10 1.10 1.10 1.10 1.00 Properties of cured Flexural modulus (23 C., GPa 3.80 3.90 3.85 3.80 4.00 3.80 resin 50% RH): E.sub.23 Flexural modulus (under wet GPa 3.25 3.20 3.25 3.25 3.40 3.30 heating at 82 C.): E.sub.82 E.sub.82/E.sub.23 0.86 0.82 0.84 0.86 0.85 0.87 Dry Tg C. 168 169 167 163 164 168 Wet Tg C. 158 157 156 155 156 161 Wet Tg/dry Tg 0.94 0.93 0.93 0.95 0.95 0.96 Rubbery state elastic MPa 5.2 5.8 6.1 6.3 6.5 5.0 modulus Water absorption % 2.0 2.2 1.8 1.7 1.6 1.8 coefficient K1c MPa .Math. m.sup.0.5 1.2 1.2 1.1 1.1 0.8 1.1 Properties of uncured Mass reduction rate after mass % 0.16 0.15 0.16 0.10 0.11 0.19 resin 30 minutes at 110 C. Viscosity at 110 C.: .sub.0 mPa .Math. s 20 22 27 40 33 37

TABLE-US-00006 TABLE 4-1 Comparative Comparative |Comparative Comparative Raw materials of epoxy resin composition Example 1 Example 2 Example 3 Example 4 Component [A]: SUMI-EPOXY.sup. ELM-434VL Tetraglycidyl 25 tetrafunctional glycidyl Araldite MY721 diaminodiphenylmethane 25 45 amine type epoxy resin SUMI-EPOXY ELM434 Component [C]: TOREP.sup. A-204E Diglycidyl-p- glycidylaniline type epoxy phenoxyaniline resin represented by Formula (I) Component [E]: at least one EPICLON.sup. HP-7200L Dicyclopentadiene solid epoxy resin selected EPICLON.sup. HP-7200H type epoxy resin 30 from the group consisting jER.sup. YX-4000 Biphenyl type epoxy of dicyclopentadiene type resin epoxy resins, biphenyl type NC-3000L Phenol aralkyl type epoxy resins, phenol epoxy resin aralkyl type epoxy resins, and naphthalene type epoxy resins Component [F]: another GAN Glycidylaniline 30 epoxy resin jER.sup. 828 Bisphenol A type 40 epoxy resin EPICLON.sup. 830 Bisphenol F type 17 30 epoxy resin jER.sup. 630 Triglycidyl-p- 70 30 aminophenol Mixture of core-shell Kane Ace MX-416 [D]: core-shell type 4.27 5 5 5 type rubber particle and Masterbatch containing rubber particle epoxy resin 25 mass % of core shell Tetrafunctional 12.81 15 15 15 rubber particles glycidyl amine type epoxy resin (component [A]) Mixture of core-shell Kane Ace MX-267 [D]: core-shell type type rubber particle and Masterbatch containing rubber particle epoxy resin 37 mass % of core shell Bisphenol F type rubber particles epoxy resin (component [F]) Component [B]: at least jERcure WA Diethyltoluenediamine 18.0 15.0 9.5 one aromatic amine Ethacure.sup. 300 Dimethylthiotoluene curing agent selected diamine from alkylbenzenediamine Lonzacure.sup. M-MIPA 4,4-Methylenebis(2- 40.0 34.0 28.9 and methylenebisaniline isopropyl-6- methylaniline) Lonzacure.sup. M-CDEA 4,4-Methylenebis (3- 104.0 chloro-2,6- diethylaniline) Another curing agent SEIKACURE S 4,4-Diaminodiphenyl sulfone Mh/Me 1.18 1.09 1.04 0.90 Properties of cured Flexural modulus (23 C., GPa 3.80 3.40 3.30 3.80 resin 50% RH): E.sub.23 Flexural modulus (under wet GPa 2.60 2.40 2.40 3.00 heating at 82 C.): E.sub.82 E.sub.82/E.sub.23 0.68 0.71 0.73 0.79 Dry Tg C. 175 184 182 179 Wet Tg C. 155 160 158 163 Wet Tg/dry Tg 0.89 0.87 0.87 0.91 Rubbery state elastic MPa 10.0 12.0 10.1 4.6 modulus Water absorption % 3.0 2.8 2.7 2.1 coefficient K1c MPa .Math. m.sup.0.5 0.9 0.8 0.9 1.0 Properties of uncured Mass reduction rate after mass % 0.22 0.19 0.16 0.41 resin 30 minutes at 110 C. Viscosity at 110 C.: .sub.0 mPa .Math. s 50 14 19 32

TABLE-US-00007 TABLE 4-2 Comparative Comparative Comparative Raw materials of epoxy resin composition Example 5 Example 6 Example 7 Component [A]: SUMI-EPOXY ELM- Tetraglycidyl 25 tetrafunctional glycidyl 434VL diaminodiphenylmethane amine type epoxy resin Araldite MY721 SUMI-EPOXY ELM434 70 Component [C]: TOREP A-204E Diglycidyl-p- 30 20 glycidylaniline type epoxy phenoxyaniline resin represented by Formula (I) Component [E]: at least one EPICLON HP-7200L Dicyclopentadiene solid epoxy resin selected EPICLON HP-7200H type epoxy resin 25 30 from the group consisting jER YX-4000 Biphenyl type epoxy of dicyclopentadiene type resin epoxy resins, biphenyl type NC-3000L Phenol aralkyl type epoxy resins, phenol epoxy resin aralkyl type epoxy resins, and naphthalene type epoxy resins Component [F]: another GAN Glycidylaniline epoxy resin jER 828 Bisphenol A type epoxy resin EPICLON 830 Bisphenol F type 30 epoxy resin jER 630 Triglycidyl-p- 31 aminophenol Mixture of core-shell Kane Ace MX-416 [D]: core-shell type 5 type rubber particle and Masterbatch containing rubber particle epoxy resin 25 mass % of core shell Tetrafunctional 15 rubber particles glycidyl amine type epoxy resin (component [A]) Mixture of core-shell Kane Ace MX-267 [D]: core-shell type 5 type rubber particle and Masterbatch containing rubber particle epoxy resin 37 mass % of core shell Bisphenol F type 8.5 rubber particles epoxy resin (component [F]) Component [B]: at least jERcure WA Diethyltoluenediamine 14.9 13.5 one aromatic amine Ethacure 300 Dimethylthiotoluene curing agent selected diamine from alkylbenzenediamine Lonzacure M-MIPA 4,4-Methylenebis(2- 29.0 26.1 and methylenebisaniline isopropyl-6- methylaniline) Lonzacure M-CDEA 4,4-Methylenebis(3- chloro-2,6- diethylaniline) Another curing agent SEIKACURE S 4,4-Diaminodiphenyl 50.0 sulfone Mh/Me 1.05 1.00 1.00 Properties of cured Flexural modulus (23 C., GPa 4.20 3.15 3.20 resin 50% RH): E.sub.23 Flexural modulus (under wet GPa 3.00 2.30 2.40 heating at 82 C.): E.sub.82 E.sub.82/E.sub.23 0.71 0.73 0.75 Dry Tg C. 194 153 176 Wet Tg C. 145 134 156 Wet Tg/dry Tg 0.75 0.88 0.89 Rubbery state elastic MPa 6.2 10.0 9.8 modulus Water absorption % 3.5 2.7 2.4 coefficient K1c MPa .Math. m.sup.0.5 0.6 0.8 0.8 Properties of uncured Mass reduction rate after mass % 0.11 0.17 0.14 resin 30 minutes at 110 C. Viscosity at 110 C.: .sub.0 mPa .Math. s 230 20 32

[0181] The unit of each component in Tables is parts by mass.

[0182] The properties of the fiber-reinforced composite material of each Example are as follows.

Example 1

[0183] For the resin composition shown in Table 5, a fiber-reinforced composite material was prepared in accordance with <Preparation of Fiber-Reinforced Composite Material> described above.

[0184] The open hole compression of this fiber-reinforced composite material was acquired in accordance with (8) Method of Evaluating Open Hole Compression (23 C., 50% RH): OHC.sub.23 of Fiber-Reinforced Composite Material and (9) Method of Evaluating Open Hole Compression (82 C. under wet condition): OHC.sub.82 of Fiber-Reinforced Composite Material described above. As a result, OHC.sub.23 was 316 MPa, OHC.sub.82 was 250 MPa, and OHC.sub.82/OHC.sub.23 was 0.79, showing an excellent compression property at the time of wet heating. The compression strength after impact was acquired, and as a result, an excellent impact resistance of 307 MPa was exhibited.

Examples 6, 12, 16, 18

[0185] Fiber-reinforced composite materials were prepared and evaluated in the same manner as in Example 1 except that the resin composition was changed as shown in Table 5.

[0186] OHC.sub.23, OHC.sub.82, and CAI of the fiber-reinforced composite material of each Example were evaluated. As a result, excellent compression properties at the time of wet heating and excellent compression strength after impact were exhibited at all levels.

Comparative Example 1

[0187] Fiber-reinforced composite materials were prepared and evaluated in the same manner as in Example 1 except that the resin composition was changed as shown in Table 5.

[0188] In this fiber-reinforced composite material, OHC.sub.23 was 311 MPa, OHC.sub.82 was 200 MPa, and OHC.sub.82/OHC.sub.23 was as low as 0.64. In addition, CAI was 269 MPa, and thus the impact resistance was also insufficient.

Comparative Example 7

[0189] Fiber-reinforced composite materials were prepared and evaluated in the same manner as in Example 1 except that the resin composition was changed as shown in Table 5.

[0190] In the fiber-reinforced composite material, OHC.sub.23 was 264 MPa, and the compression strength under a room temperature environment was low. Furthermore, OHC.sub.82 was 191 MPa, and the compression property at the time of wet heating was low. In addition, CAI was 255 MPa, and thus the impact resistance was also insufficient.

TABLE-US-00008 TABLE 5-1 Example Example Example Example Example Raw materials of epoxy resin composition 1 6 12 16 18 Component [A]: SUMI-EPOXY.sup. ELM-434VL Tetraglycidyl 25 45 25 40 40 tetrafunctional glycidyl Araldite MY721 diaminodiphenylmethane amine type epoxy resin SUMI-EPOXY ELM434 Component [C]: TOREP.sup. A-204E Diglycidyl-p- 30 40 30 20 20 glycidylaniline type epoxy phenoxyaniline resin represented by Formula (I) Component [E]: at least one EPICLON.sup. HP-7200L Dicyclopentadiene 25 10 solid epoxy resin selected EPICLON.sup. HP-7200H type epoxy resin from the group consisting jER.sup. YX-4000 Biphenyl type epoxy 30 30 of dicyclopentadiene type resin epoxy resins, biphenyl type NC-3000L Phenol aralkyl type 15 epoxy resins, phenol epoxy resin aralkyl type epoxy resins, and naphthalene type epoxy resins Component [F]: another GAN Glycidylaniline epoxy resin jER.sup. 828 Bisphenol A type epoxy resin EPICLON.sup. 830 Bisphenol F type epoxy resin jER.sup. 630 Triglycidyl-p- aminophenol Mixture of core-shell Kane Ace MX-416 [D]: core-shell type 5 5 5 5 5 type rubber particle and Masterbatch containing rubber particle epoxy resin 25 mass % of core shell Tetrafunctional 15 15 15 15 15 rubber particles glycidyl amine type epoxy resin (component [A]) Mixture of core-shell Kane Ace MX-267 [D]: core-shell type type rubber particle and Masterbatch containing rubber particle epoxy resin 37 mass % of core shell Bisphenol F type rubber particles epoxy resin (component [F]) Component [B]: at least jERcure WA Diethyltoluenediamine 9.5 16.2 16.3 one aromatic amine Ethacure.sup. 300 Dimethylthiotoluene 41.6 41.2 curing agent selected diamine from alkylbenzenediamine Lonzacure.sup. M-MIPA 4,4-Methylenebis(2- 28.4 31.5 31.6 and methylenebisaniline isopropyl-6- methylaniline) Lonzacure.sup. M-CDEA 4,4-Methylenebis (3- chloro-2,6- diethylaniline) Another curing agent SEIKACURE S 4,4-Diaminodiphenyl sulfone Mh/Me 0.90 1.00 1.20 1.10 1.10 Properties of fiber- OHC (23 C., 50% RH): OHC.sub.23 MPa 316 321 329 317 324 reinforced composite OHC (under wet heating MPa 250 231 236 248 255 material at 82 C.): OHC.sub.82 OHC.sub.82/OHC.sub.23 0.79 0.72 0.72 0.78 0.79 CAI MPa 307 295 284 310 295

TABLE-US-00009 TABLE 5-2 Comparative Comparative Raw materials of epoxy resin composition Example 1 Example 7 Component [A]: SUMI-EPOXY ELM-434VL Tetraglycidyl 25 tetrafunctional glycidyl Araldite MY721 diaminodiphenylmethane amine type epoxy resin SUMI-EPOXY ELM434 Component [C]: TOREPR A-204E Diglycidyl-p- glycidylaniline type epoxy phenoxyaniline resin represented by Formula (I) Component [E]: at least one EPICLON HP-7200L Dicyclopentadiene type solid epoxy resin selected EPICLON HP-7200H epoxy resin 30 from the group consisting jER YX-4000 Biphenyl type epoxy of dicyclopentadiene type resin epoxy resins, biphenyl type NC-3000L Phenol aralkyl type epoxy resins, phenol epoxy resin aralkyl type epoxy resins, and naphthalene type epoxy resins Component [F]: another GAN Glycidylaniline epoxy resin jER 828 Bisphenol A type epoxy resin EPICLON 830 Bisphenol F type epoxy 17 30 resin jER 630 Triglycidyl-p- 70 aminophenol Mixture of core-shell Kane Ace MX-416 [D]: core-shell type 4.27 5 type rubber particle and Masterbatch containing 25 rubber particle epoxy resin mass % of core shell Tetrafunctional 12.81 15 rubber particles glycidyl amine type epoxy resin (component [A]) Mixture of core-shell Kane Ace MX-267 [D]: core-shell type type rubber particle and Masterbatch containing 37 rubber particle epoxy resin mass % of core shell Bisphenol F type epoxy rubber particles resin (component [F]) Component [B]: at least jERcure WA Diethyltoluenediamine 13.5 one aromatic amine Ethacure 300 Dimethylthiotoluene curing agent selected diamine from alkylbenzenediamine Lonzacure M-MIPA 4,4-Methylenebis(2- 26.1 and methylenebisaniline isopropyl-6-methylaniline) Lonzacure M-CDEA 4,4-Methylenebis(3- 104.0 chloro-2, 6-diethylaniline) Another curing agent SEIKACURE S 4,4-Diaminodiphenyl sulfone Mh/Me 1.18 1.00 Properties of fiber- OHC (23 C., 50% RH): OHC.sub.23 MPa 311 264 reinforced composite OHC (under wet heating at MPa 200 191 material 82 C.): OHC.sub.82 OHC.sub.82/OHC.sub.23 0.64 0.72 CAI MPa 269 255

INDUSTRIAL APPLICABILITY

[0191] The epoxy resin composition for RTM of the present invention can provide a cured epoxy resin having a low viscosity and low volatility and having a high elastic modulus and high fracture toughness at the time of wet heating. A fiber-reinforced composite material including the epoxy resin composition is also excellent in a compression property and impact resistance at the time of wet heating, and thus can be suitably used in aerospace members and structural members for general industries.