Prepreg, fiber-reinforced composite material, aircraft member, and aircraft

Abstract

To achieve both high toughness and high elastic modulus of an interlayer resin layer in order to balance high impact resistance and high compressive strength in FRP.SOLUTION: A prepreg comprises the following components [A] to [C], the prepreg having a fiber layer comprising components [A] and [B], with a resin layer comprising components [B] and [C] disposed on at least one side of the fiber layer. [A] reinforcing fiber, [B] thermosetting resin and [C] inorganic porous particles.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a fiber-reinforced composite material having excellent impact resistance and compressive strength, and to a prepreg, which is a precursor of the fiber-reinforced composite material. [Background technology]

[0002] In recent years, fiber-reinforced composites (FRPs), which use reinforcing fibers such as carbon fiber and aramid fiber, have been used in a variety of applications, including aircraft and automobile structural materials, sports equipment such as tennis rackets, golf shafts, and fishing rods, and general industrial applications, due to their high specific strength and specific modulus. In particular, aircraft structural materials require high impact resistance in addition to high specific strength and specific modulus. FRPs are often produced by laminating precursors containing fibers and resins, known as prepregs, and then molding them while heating and curing if the resin is a thermosetting resin. Impact loads on such laminated FRPs can lead to delamination, reducing the compressive resistance of the structure. To address this issue, one approach to improving impact resistance is to form resin layers between layers and incorporate thermoplastic particles within the resin layers. Forming resin layers with thermoplastic particles between layers increases the toughness of the interlayers and reduces delamination during impact loads. However, the resin layers between layers contain thermoplastic particles, which have a lower modulus than the cured product of the thermosetting resin, resulting in a lower modulus of elasticity. A decrease in the elastic modulus of the resin layer makes the reinforcing fibers more likely to buckle when a compressive load acts in the fiber direction of the FRP, resulting in a problem of a decrease in the compressive strength of the FRP. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-149237 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, prepregs containing inorganic particles added to resin are laminated and cured to obtain FRP, which achieves high compressive strength. The inorganic particles are considered to be non-porous, not porous. In this case, when an impact load is applied to the FRP, peeling can occur between the inorganic particles and the resin, making it difficult to increase the toughness of the resin layer between adjacent fiber layers, resulting in a problem of not being able to increase the impact resistance of the FRP as intended. When FRP is molded from a laminate, in order to achieve high impact resistance, it is necessary to suppress delamination of the FRP, so it is necessary to improve the toughness of the resin layers between the layers. Also, in order to achieve high compressive strength of FRP, it is necessary to suppress buckling of the reinforcing fibers when a compressive load is applied in the fiber direction, and to do this, it is necessary to improve the elastic modulus of the resin layers between the layers.

[0005] Therefore, an object of the present invention is to achieve both high toughness and high elastic modulus in the interlaminar resin layers in order to achieve both high impact resistance and high compressive strength in FRP. [Means for solving the problem]

[0006] 1. A prepreg comprising the following components [A] to [C]: A prepreg having a fiber layer containing components [A] and [B], and a resin layer containing components [B] and [C] disposed on at least one side of the fiber layer. [A] Reinforced fiber [B] Thermosetting resin [C] Inorganic porous particles 2. The prepreg according to item 1 above, wherein component [B] is an epoxy resin. 3. The prepreg according to 1 or 2 above, further comprising a thermoplastic resin as component [D]. 4. The prepreg according to any one of the above 1 to 3, wherein the material of the component [C] is silica. 5. The prepreg according to any one of the above 1 to 4, wherein the average particle size of the component [C] is 1 μm or more and 100 μm or less. 6. The prepreg according to any one of 1 to 5 above, wherein the pores of [C] in the resin layer are impregnated with [B]. 7. The prepreg according to any one of 1 to 6 above, wherein a resin layer is disposed on both sides of the fiber layer. 8. The prepreg according to any one of 1 to 7 above, wherein the component [A] is carbon fiber. 9. A fiber-reinforced composite material obtained by curing the prepreg according to any one of 1 to 8 above. 10. An aircraft component comprising the fiber-reinforced composite material described in 9 above. 11. An aircraft including the component described in 10 above.

[0007] Hereinafter, the components [A], [B], [C], and [D] may be simply referred to as [A], [B], [C], and [D], respectively. [Effects of the Invention]

[0008] The prepreg of the present invention is capable of achieving both high toughness and a high elastic modulus in the resin layer in the FRP obtained by laminating and curing, and thus can exhibit both high impact resistance and high compressive strength. DETAILED DESCRIPTION OF THE INVENTION

[0009] The prepreg and fiber-reinforced composite material of the present invention will be described below. In the present invention, a resin composition containing the thermosetting resin [B] is referred to as a thermosetting resin composition, and a mixture of the thermosetting resin composition and inorganic or organic particles including inorganic porous particles [C] is referred to as a thermosetting resin mixture. ([A] Reinforced fiber) The reinforcing fibers [A] of the prepreg of the present invention may include glass fibers, carbon fibers, aramid fibers, boron fibers, alumina fibers, and silicon carbide fibers. The diameter of the single reinforcing fibers is preferably 3 μm or more and 10 μm or less. If the diameter of the single reinforcing fibers is smaller than 3 μm, a large amount of inorganic porous particles from the resin layer may flow into the fiber layer when the prepreg is cured in an autoclave, causing the reinforcing fibers to bend due to the inorganic porous particles, resulting in a decrease in compressive strength. Furthermore, if the diameter of the single reinforcing fibers is larger than 10 μm, the fiber content in the FRP may be reduced, resulting in a decrease in the tensile strength of the FRP in the fiber direction.

[0010] Among these fibers, carbon fiber is preferred because it provides an FRP with excellent strength and elastic modulus under tension or compression. The form of the reinforcing fiber is not particularly limited, and examples that can be used include unidirectionally aligned long fibers, tow, woven fabric, mat, knit, braided cord, etc. ([B] Thermosetting resin) Examples of the thermosetting resin [B] include epoxy resins, vinyl ester resins, unsaturated polyester resins, phenolic resins, benzoxazine resins, urethane resins, urea resins, melamine resins, maleimide resins, cyanate resins, and diallyl phthalate resins. A combination of these resins may also be used. Furthermore, the thermosetting resin may be used as a resin composition together with a curing agent, a curing accelerator, a filler, and the like.

[0011] Among these thermosetting resins, epoxy resins are preferred because the cured product has excellent mechanical properties and heat resistance, as well as excellent toughness and elongation.

[0012] Examples of curing agents used with epoxy resins include aromatic amines such as diaminodiphenylmethane and diaminodiphenylsulfone, aliphatic amines, imidazole derivatives, dicyandiamide, tetramethylguanidine, thiourea-added amines, carboxylic acid anhydrides such as methylhexahydrophthalic anhydride, carboxylic acid hydrazides, carboxylic acid amides, polyphenol compounds, novolac resins, polymercaptans, and Lewis acid complexes such as boron trifluoride ethylamine complexes. ([C]Inorganic porous particles) The resin layer disposed on at least one side, preferably both sides, of the fiber layer of the prepreg of the present invention contains inorganic porous particles [C] to improve the elastic modulus and toughness of the resin layer. The technique of adding inorganic particles to a thermosetting resin to improve the elastic modulus of the cured thermosetting resin is widely known. However, in cured thermosetting resin mixtures containing commonly used inorganic non-porous particles, delamination occurs at the interface between the inorganic non-porous particles and the cured thermosetting resin when cracks propagate through the interior, resulting in low toughness. In contrast, cured thermosetting resin mixtures containing inorganic porous particles can have relatively high elastic modulus and toughness. When a thermosetting resin is kneaded with inorganic porous particles, the thermosetting resin can partially or entirely impregnate the pores of the particles. When the thermosetting resin impregnates the pores of the particles and then hardens, the anchor effect reduces the likelihood of delamination at the interface between the particles and the cured thermosetting resin. Furthermore, the interior of the inorganic porous particles is reinforced by the cured product of the thermosetting resin, improving the toughness of the particles, and as a result, the toughness of the cured product of the thermosetting resin mixture is also improved. Therefore, it is preferable that the thermosetting resin is impregnated into the pores of the inorganic porous particles in the resin layer. Such impregnation into the pores can be confirmed by observing the cross section of the inorganic porous particles after curing and determining whether or not the cured product of the thermosetting resin composition is present in the pores.

[0013] Examples of inorganic porous particle materials include silica, alumina, zirconia, titanium oxide, glass, and silicate minerals, and those having an elastic modulus at least three times higher than that of the cured product of the thermosetting resin composition are preferably used. Among these, silica is preferred because it is easy to process even when the particles are fine particles and is a readily available material.

[0014] It is preferable that the inorganic porous particles are unevenly distributed in the resin layer, as this can improve the toughness of the resin layer and suppress delamination. "Uneven distribution" means that the difference between the percentage of inorganic porous particles in the resin layer (hereinafter referred to as the particle percentage in the resin layer) and the percentage of inorganic porous particles in the fiber layer (hereinafter referred to as the particle percentage in the fiber layer) is 30% or more. The difference between the particle percentage in the resin layer and the particle percentage in the fiber layer is called the uneven distribution of inorganic porous particles, and can be confirmed by the following method. The prepreg is cut into 100mm x 100mm pieces, laminated 10 plies, and then cured in an autoclave at 180°C for 2 hours under a pressure of 0.6MPa to obtain FRP. The FRP is cut in-plane at a random position, and the cross section is polished. A 1mm wide cross section is then photographed at 200x magnification using an optical microscope.

[0015] In the captured image, among the points where an arbitrary line (hereinafter referred to as the arbitrary line) parallel to the out-of-plane direction of the FRP intersects with a single fiber of the 5th ply fiber layer counting from the top, the point closest to the 6th ply is defined as the 5th ply lower fiber intersection point. Furthermore, among the points where the arbitrary line intersects with a single fiber of the 6th ply fiber layer counting from the top, the point closest to the 5th ply is defined as the 6th ply upper fiber intersection point. The distance indicated by the line segment from the 5th ply lower fiber intersection point to the 6th ply upper fiber intersection point is defined as the thickness of the resin layer. The ratio of the length of the inorganic porous particles located on the line segment indicating the thickness of the resin layer and occupying the line segment to the thickness of the resin layer is defined as the particle proportion of the resin layer.

[0016] Among the points where the arbitrary line intersects with a fiber unit of the sixth ply of the fiber layer counting from the top, the point closest to the seventh ply is defined as the 6-ply lower fiber intersection point. The distance indicated by the line segment from the 6-ply lower fiber intersection point to the 6-ply upper fiber intersection point is defined as the thickness of the fiber layer, and the ratio of the length of the inorganic porous particles located on the line segment indicating the thickness of the fiber layer and occupying that line segment to the thickness of the fiber layer is defined as the particle proportion of the fiber layer.

[0017] This operation is repeated 100 times at 10 μm intervals across the entire image in the direction perpendicular to the out-of-plane direction of the FRP, and the individual values ​​for the particle ratio in the resin layer and the particle ratio in the fiber layer are obtained. The average values ​​for each of the particle ratios in the resin layer and the fiber layer are calculated. The difference between the average particle ratios in the resin layer and the fiber layer is calculated as the degree of uneven distribution of inorganic porous particles.

[0018] The average particle size of the inorganic porous particles is preferably in the range of 1 μm or more and 100 μm or less, and more preferably in the range of 5 μm or more and 40 μm or less. If the average particle size of the inorganic porous particles is larger than the above range, the large particles may disrupt the arrangement of the reinforcing fibers, which may reduce the compressive strength of the FRP. If the average particle size of the inorganic porous particles is smaller than the above range, the inorganic porous particles may pass between the fibers and flow into the fiber layer during FRP curing, which may reduce the impact resistance of the FRP. Here, the average particle size of the inorganic porous particles is determined by observing the inorganic porous particles at 2000x magnification with a laser microscope, and the diameter of the circle circumscribing the periphery of the particle in the observed image is used as the individual particle size, and the average value of the individual particle sizes of 50 arbitrarily selected particles is used.

[0019] [C] The inorganic porous particles are preferably uncoated. If the inorganic porous particles are coated, the thermosetting resin composition will not penetrate well into the inorganic porous particles when kneaded with the thermosetting resin composition and cured, which may reduce the toughness of the inorganic porous particles and decrease the impact resistance of the FRP.

[0020] Commercially available inorganic porous particles include "SiO2MS-2.2 2-19 μm" (COSPHERIC), "DiagNanotm C18 Porous Silica Particles, 30 μm" (CD Biopaticles), "DiagNanotm Plain Porous Silica Particles", PSP-06 (CD Biopaticles), and "Silica mesoporous SBA-15" (Merck). ([D]Thermoplastic resin) The thermosetting resin composition of the present invention may contain a thermoplastic resin [D]. The thermoplastic resin [D] to be kneaded is soluble in the thermosetting resin. Furthermore, using a thermoplastic resin having a polyaryl ether skeleton is preferable from the viewpoint of improving the elastic modulus without reducing the toughness of the resin layer. Examples of thermoplastic resins having a polyaryl ether skeleton include polysulfone, polyphenyl sulfone, polyether sulfone, polyether imide, polyphenylene ether, polyether ether ketone, and polyether ether sulfone. These thermoplastic resins having a polyaryl ether skeleton may be used alone or in combination. The amount of the thermoplastic resin in the thermosetting resin composition is preferably 1% or more and less than 50% by mass. In the present invention, the thermoplastic resin [D] may be contained in either the fiber layer or the resin layer, and is preferably contained in both layers.

[0021] In particular, to obtain high toughness, the glass transition temperature (Tg) of the thermoplastic resin is preferably 150°C or higher, more preferably 170°C or higher. If the glass transition temperature of the thermoplastic resin to be blended is less than 150°C, high toughness may not be obtained. Furthermore, the terminal functional group of the thermoplastic resin is preferably a hydroxyl group, a carboxyl group, or a thiol group, and it is also preferable to use an acid anhydride. The terminal functional group of such a thermoplastic resin reacts with the epoxy resin, thereby improving the toughness of the cured product of the thermosetting resin composition. Specifically, commercially available polyethersulfone products include "Sumikaexcel (registered trademark)" PES3600P, "Sumikaexcel (registered trademark)" PES5003P, "Sumikaexcel (registered trademark)" PES5200P, and "Sumikaexcel (registered trademark)" PES7200P (all manufactured by Sumitomo Chemical Co., Ltd.), "Virantage (registered trademark)" VW-10200RFP, and "Virantage (registered trademark)" VW-10700RFP (all manufactured by Solvay Chemical Industries, Ltd.). Other examples include copolymer oligomers of polyethersulfone and polyetherethersulfone as described in JP-A-2004-506789, and commercially available polyetherimide products such as "Ultem (registered trademark)" 1000, "Ultem (registered trademark)" 1010, and "Ultem (registered trademark)" 1040 (all manufactured by SABIC Corporation). An oligomer refers to a polymer with a relatively low molecular weight in which a finite number of monomers, approximately 10 to 100, are bonded. (prepreg) The prepreg of the present invention can be produced by various known methods, such as a wet method in which a thermosetting resin is dissolved in an organic solvent selected from acetone, methyl ethyl ketone, and methanol to reduce the viscosity and then impregnated into reinforcing fibers, or a hot melt method in which a thermosetting resin is heated without using an organic solvent to reduce the viscosity and then impregnated into reinforcing fibers.

[0022] In the wet method, the reinforcing fibers are immersed in a liquid containing a thermosetting resin, then pulled out, and the organic solvent is evaporated using an oven or the like to obtain a prepreg.

[0023] In addition, the hot melt method can be used in a method in which a thermosetting resin whose viscosity has been reduced by heating is directly impregnated into reinforcing fibers, or in a method in which a release paper sheet with a resin film (hereinafter referred to as a "resin film") is first prepared by coating a thermosetting resin on release paper or the like, and then the resin film is placed on both sides of the sheet-like reinforcing fibers on the reinforcing fiber side, and the reinforcing fibers are impregnated with the thermosetting resin by heating and pressurizing.

[0024] The method for producing the prepreg of the present invention is preferably a hot melt method in which the thermosetting resin is impregnated into the reinforcing fibers without using an organic solvent, since this method results in substantially no organic solvent remaining in the prepreg.

[0025] The prepreg of the present invention has a fiber layer containing [A] reinforcing fibers and [B] a thermosetting resin, and a resin layer containing [B] a thermosetting resin and [C] inorganic porous particles, with the resin layer located on at least one side of the fiber layer, or the resin layer may be located on both sides of the fiber layer. The resin layer forms an interlayer when the prepreg is laminated, and typically does not contain [A] reinforcing fibers, although this does not necessarily preclude the inclusion of reinforcing fibers. The prepreg of the present invention can be produced by several methods, including the following specific methods. A multi-stage impregnation hot-melt method is used, in which a thermosetting resin composition containing [B] a thermosetting resin is impregnated in multiple stages from both sides or one side of the [A] reinforcing fibers by heating and pressurizing them. In the multi-stage impregnation hot-melt method, the number of times the thermosetting resin composition is impregnated into the [A] reinforcing fibers is not limited, but the production costs increase as the number of times increases. Therefore, a two-stage impregnation hot-melt method is preferably used, in which a thermosetting resin composition is divided into two portions and impregnated into the [A] reinforcing fibers from both sides or one side by heating and pressurizing. This operation is repeated twice to perform two steps. In the two-stage impregnation hot-melt method, a first resin film containing a [B] thermosetting resin is impregnated into the [A] reinforcing fibers from both sides or one side, and then a second resin film containing a [B] thermosetting resin and [C] inorganic porous particles is attached to both sides or one side of the first resin film to obtain a prepreg. In this case, the first resin film usually does not contain the [C] inorganic porous particles. In this method, the thermosetting resin composition contained in the first resin film and the thermosetting resin composition obtained by removing the [C] inorganic porous particles from the thermosetting resin mixture contained in the second resin film preferably have the same composition from the perspective of prepreg productivity, but they may have different compositions. The fiber layer and the resin layer may have different compositions in order to individually adjust the degree of impregnation of the [B] thermosetting resin between the [A] reinforcing fibers in the fiber layer or the degree of impregnation of the [C] inorganic porous particles in the resin layer with the [B] thermosetting resin. Also, when there is a need to adjust the performance of the prepreg or FRP, such as when it is desired to adjust the surface tackiness to a specific level, the two may have different compositions.In addition, the composition of either or both of the first and second resin films may contain a thermoplastic resin (D).

[0026] In the FRP obtained by curing the prepreg of the present invention, the average thickness of the resin layer is preferably in the range of 10 μm to 50 μm. If the average thickness of the resin layer is greater than 50 μm, the volume fraction of the reinforcing fibers may be reduced, potentially reducing the compressive strength of the FRP. Furthermore, if the average thickness of the resin layer is less than 10 μm, the resin layer may not adequately absorb the impact energy when an impact is applied to the FRP, potentially reducing the impact resistance of the FRP. The thickness of the resin layer of the FRP is measured as described above. The distance between the fifth and sixth fiber layers counting from the top is considered to be the individual thickness values ​​of the resin layer. In the image obtained by the above method, the thickness of the resin layer is measured every 10 μm across the entire direction perpendicular to the out-of-plane direction of the FRP, and the average value is taken as the average resin layer thickness.

[0027] FRP can be obtained by curing the prepreg of the present invention. The obtained FRP has high compressive strength and high impact resistance, making it suitable for aircraft components. Note that aircraft include not only aircraft that fly in the atmosphere, but also spacecraft such as space shuttles and rockets. [Example]

[0028] The prepreg and FRP of the present invention will be described in more detail below using examples. The raw materials, production methods, and evaluation methods used in the examples are shown below, but the raw materials and production methods are not limited to those described. The production environment and evaluation of the thermosetting resin compositions in the examples were carried out in an atmosphere of a temperature of 25°C ± 2°C and a relative humidity of 50%, unless otherwise specified. <[B]Thermosetting resin> "EPON (registered trademark)" 825 (bisphenol A type epoxy resin [BisA], manufactured by Mitsubishi Chemical Corporation). ELM434 (tetraglycidyldiaminodiphenylmethane [TGDDM], manufactured by Sumitomo Chemical Co., Ltd.). <[C]Inorganic porous particles> SIO2MS-2.2 2-19μm (porous silica particles, COSPHERIC). <Inorganic non-porous particles> P2011SL-2.5 3-6μm (non-porous silica particles, COSPHERIC). <Organic porous particles> Orgasol 2002 D NAT (porous nylon particles, manufactured by Arkema). <Organic non-porous particles> Nylon 12 particles SP-10 (non-porous nylon particles [PA12], manufactured by Toray Industries, Inc.). <[D]Thermoplastic resin> "Sumikaexcel (registered trademark)" PES5003P (polyethersulfone, manufactured by Sumitomo Chemical Co., Ltd.). <Curing agent> "Seikacure (registered trademark)"-S (4,4'-diaminodiphenyl sulfone [4,4'-DDS], manufactured by Wakayama Seika Co., Ltd.). (1) Preparation of thermosetting resin compositions and mixtures [B] Thermosetting resin and [D] thermoplastic resin were kneaded in the ratios shown in Table 1, heated to 150°C or higher, and stirred for 1 hour to dissolve the thermoplastic resin, yielding a transparent viscous liquid. After the temperature of this liquid was lowered while kneading, a curing agent was added in the amount of parts by mass shown in Table 1 so that the epoxy equivalent was 1.0, and the mixture was kneaded to obtain thermosetting resin compositions 1 and 2. Then, while heating thermosetting resin composition 1 or 2 to 80°C, the above-mentioned particles were added as shown in Table 2, and the mixture was kneaded to obtain thermosetting resin mixtures of the examples and comparative examples. Note that the mass ratio of thermosetting resin to curing agent was the same in thermosetting resin compositions 1 and 2. Hereinafter, the thermosetting resin composition and the thermosetting resin mixture may be simply referred to as the composition and the mixture. (2) Evaluation method for toughness K of cured thermosetting resin composition or mixture The composition or mixture prepared in (1) was degassed in a vacuum and then poured into a mold with a thickness of 6 mm, using a 6 mm Teflon® spacer. It was then cured in an autoclave at 180°C and 0.6 MPa for 2 hours to obtain a 6 mm thick cured plate. The resulting cured plate was machined into the shape of a test piece specified in ASTM D5045-99(2007) and then subjected to the SENB test according to ASTM D5045-99(2007) to obtain a value. Ten test pieces were prepared, and the average of the measured values ​​was taken as the toughness (K). (3) Method for evaluating the flexural modulus E of a cured thermosetting resin composition or mixture The composition or mixture prepared in (1) was degassed in a vacuum and then poured into a mold with a thickness of 2 mm, using a 2 mm Teflon® spacer. The mixture was then cured in an autoclave at 180°C and 0.6 MPa for 2 hours to obtain a 2 mm thick cured plate. Rectangular test pieces measuring 10 mm wide and 60 mm long were cut from the cured plate and subjected to three-point bending in accordance with JIS K7171 (1994) using an Instron universal testing machine (manufactured by Instron Corporation) at a span of 32 mm and a test speed of 10 mm / min to measure the flexural modulus (E). Six test pieces were prepared, and the average of the measured values ​​was taken as the flexural modulus (E). (4) Evaluation of impregnation in the pores of inorganic porous particles The cured plate obtained by method (2) was cut in the thickness direction at a random position, and the cut surface was polished until the pores of the porous particles could be clearly observed. Platinum was vapor-deposited on the polished cut surface, and then SEM observation was performed at 30,000 times magnification. Ten inorganic porous particles observed on the cut surface were randomly selected and observed. If the cured product of the thermosetting resin composition was confirmed in the pores of one or more inorganic porous particles, it was judged as impregnation (○), and if not, it was judged as not impregnation (×). Examples 1 to 2, Comparative Examples 1 to 4 Compositions and mixtures were prepared as described in (1) above using the compositions shown in Tables 1 and 2, respectively, and the toughness, flexural modulus, and impregnation of the inorganic porous particles into the pores of the cured products were evaluated using the methods shown in (2), (3), or (4) above, respectively. The results are shown in Table 2.

[0029] A comparison between Example 1 and Comparative Example 1 showed that by using inorganic porous particles instead of organic porous particles, the cured product achieved similar high toughness while also improving its flexural modulus.

[0030] A comparison between Example 1 and Comparative Example 2 showed that by using inorganic porous particles instead of organic non-porous particles, the cured product achieved equivalent high toughness while also improving its flexural modulus.

[0031] A comparison between Example 1 and Comparative Example 3 showed that by using inorganic porous particles instead of inorganic non-porous particles, the cured product achieved an equally high flexural modulus while also improving toughness.

[0032] Comparison of Example 1 and Comparative Example 4 shows that the addition of inorganic porous particles improves the toughness of the cured product, and further improves the flexural modulus.

[0033] Comparing Example 1 and Example 2, it was found that by adding inorganic porous particles and a thermoplastic resin to a thermosetting resin, the flexural modulus was further improved while maintaining high toughness.

[0034] [Table 1]

[0035] [Table 2]

Claims

1. A prepreg comprising the following components [A] to [C]: A prepreg having a fiber layer containing components [A] and [B], and a resin layer containing components [B] and [C] disposed on at least one surface of the fiber layer. [A] Reinforced fiber [B] Thermosetting resin [C] Inorganic porous particles

2. 2. The prepreg according to claim 1, wherein component [B] is an epoxy resin.

3. The prepreg according to claim 1, further comprising a thermoplastic resin as a component [D].

4. 2. The prepreg according to claim 1, wherein the material of the component [C] is silica.

5. 2. The prepreg according to claim 1, wherein the average particle size of the component [C] is 1 μm or more and 100 μm or less.

6. 2. The prepreg according to claim 1, wherein the resin layer is impregnated with [B] in pores of [C].

7. The prepreg according to claim 1 , wherein a resin layer is disposed on both sides of the fiber layer.

8. The prepreg according to any one of claims 1 to 7, wherein the component [A] is a carbon fiber.

9. A fiber-reinforced composite material obtained by curing the prepreg according to any one of claims 1 to 7.

10. A fiber-reinforced composite material obtained by curing the prepreg according to claim 8.

11. An aircraft component comprising the fiber-reinforced composite material of claim 9.

12. An aircraft component comprising the fiber-reinforced composite material of claim 10.

13. An aircraft comprising a member according to claim 11 or 12.

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