JP2006274110A - Prepreg and fiber-reinforced composite material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a fiber-reinforced composite material that is lightweight, has excellent mechanical properties such as strength, modulus of elasticity, etc., and impact resistance and a prepreg for producing a fiber-reinforced composite material that is lightweight and has excellent mechanical properties such as strength, modulus of elasticity, etc., and impact resistance. <P>SOLUTION: The fiber-reinforced composite material is a cured product of a thermosetting resin composition that comprises a reinforcing fiber and a matrix resin, in which a part or the whole of the matrix resin has 0.001-1GPa tensile modulus measured at 23°C and ≥30% tensile elongation at break measured at 23°C. The prepreg is obtained by impregnating a reinforcing fiber with a thermosetting resin composition having 0.001-1GPa tensile modulus measured at 23°C and ≥30% tensile modulus measured at 23°C. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fiber-reinforced composite material that is lightweight, excellent in mechanical properties such as strength and elastic modulus, and excellent in impact resistance. Further, the present invention relates to a prepreg that can obtain a fiber-reinforced composite material that is lightweight, excellent in mechanical properties such as strength and elastic modulus, and excellent in impact resistance.

  Fiber reinforced composite materials consisting of glass fibers, carbon fibers, aramid fibers, alumina fibers, boron fibers, etc. and matrix resins are lightweight and have excellent mechanical properties such as strength and elastic modulus. It is widely used for sports goods and automobiles.

  As the matrix resin, either a thermosetting resin or a thermoplastic resin can be used, but a thermosetting resin is often used because it has an advantage that it can be molded at a relatively low temperature. Specific examples of the thermosetting resin include unsaturated polyester resin, vinyl ester resin, epoxy resin, phenol resin and the like.

  However, when a thermosetting resin is used as the matrix resin, there is a problem that the impact resistance of the fiber-reinforced composite material is insufficient, reflecting that the toughness of the thermosetting resin is insufficient. For example, when pebbles collide with a fiber reinforced composite material using a thermosetting resin as a matrix resin, the impact strength of the fiber reinforced composite material is insufficient. There was a problem that.

  Conventionally, fiber and film made of thermoplastic resin are placed between the reinforcing fiber layers of the fiber reinforced composite material, that is, between the layers, to improve the impact resistance of the fiber reinforced composite material. Has been planned.

  As a method of arranging the fibers, it is proposed that the impact resistance of the fiber reinforced composite material is improved by arranging the fiber made of polyamide or the like between the layers of the fiber reinforced composite material using the carbon fiber as the reinforcing fiber. (For example, Patent Documents 1 to 6).

  In addition, as a method of arranging the film, the impact resistance of the fiber-reinforced composite material can be improved by arranging a film made of polyamide or the like between the layers of the fiber-reinforced composite material using carbon fibers as reinforcing fibers. It has been proposed (for example, Patent Documents 7 and 8).

  However, in these methods, the content of reinforcing fibers in the fiber-reinforced composite material, which is indicated by an index such as the fiber volume content, is reduced. When using a reinforcing fiber having a sufficiently large elastic modulus compared to the matrix resin such as glass fiber, carbon fiber, alumina fiber, boron fiber, etc., the elastic modulus in the fiber direction of the fiber reinforced composite material is the elastic modulus of the reinforcing fiber. It is known that it is generally proportional to the product of the reinforcing fiber content. Therefore, in these methods in which the content of reinforcing fibers is reduced, the characteristic of high elastic modulus, which is a great advantage of the fiber-reinforced composite material, is impaired.

Thus, a technique for improving the impact resistance of a fiber-reinforced composite material without impairing the feature of high elastic modulus has not been found so far.
Japanese Patent No. 3137671 Japanese Patent No. 3137733 Japanese Patent No. 3238719 JP-A-5-329838 JP-A-6-25917 JP-A-6-49709 U.S. Pat. No. 4,604,319 Japanese Patent No. 1869504

  The object of the present invention is to provide a technique for improving the impact resistance of a fiber-reinforced composite material without lowering the elastic modulus in view of the background of the prior art.

  The present inventors considered to improve the impact resistance of the fiber-reinforced composite material by greatly improving the impact resistance of the thermosetting resin itself used as the matrix resin. In this method, unlike the method in which fibers and films made of a thermoplastic resin are disposed between the layers, the elastic fiber content is not lowered, and therefore, it is considered that the elastic modulus is not lowered. And when the impact was added, the hardened | cured material of the thermosetting resin used as a matrix resin should just absorb a shock energy, deform | transforming easily, and various thermosetting resins were examined earnestly. As a result, it was found that the impact resistance of the fiber-reinforced composite material can be dramatically improved by using a specific thermosetting resin having a moderately low tensile elastic modulus and a sufficiently high tensile breaking elongation.

  In order to solve the above problems, the present invention employs the following means. That is, the fiber-reinforced composite material of the present invention comprises reinforcing fibers and a matrix resin, and a part or all of the matrix resin has a tensile elastic modulus measured at 23 ° C. within a range of 0.001 to 1 GPa. And a cured product of a thermosetting resin composition having a tensile elongation at break measured at 23 ° C. of 30% or more.

  The prepreg of the present invention has a thermosetting property in which the tensile modulus measured at 23 ° C. is in the range of 0.001 to 1 GPa and the tensile elongation at break measured at 23 ° C. is 30% or more. The resin composition is impregnated into a reinforcing fiber.

  The fiber-reinforced composite material of the present invention is lightweight, has excellent mechanical properties such as strength and elastic modulus, and has impact resistance, and is useful for aerospace use, sports equipment use, automobile use, etc. be able to.

  The fiber-reinforced composite material of the present invention includes reinforcing fibers and a matrix resin in order to improve the impact resistance of the fiber-reinforced composite material without lowering the elastic modulus, and part or all of the matrix resin A cured product of a thermosetting resin composition having a tensile modulus measured at 23 ° C. in the range of 0.001 to 1 GPa and a tensile elongation at break of 30% or more measured at 23 ° C. It is characterized by being. In the present invention, unless otherwise specified, the elastic modulus represents a tensile elastic modulus.

  Various fibers can be used as the reinforcing fiber in the present invention, but since a high-strength fiber-reinforced composite material is obtained, the tensile strength of the reinforcing fiber is preferably 1500 MPa or more, and is 3500 MPa or more. It is preferable that it is 4500 MPa or more. In addition, since a fiber-reinforced composite material having a high elastic modulus can be obtained, the tensile elastic modulus of the reinforcing fiber is preferably 100 GPa or more, more preferably 200 GPa or more, and further preferably 250 GPa or more. Specific examples of the reinforcing fiber include glass fiber, carbon fiber, aramid fiber, alumina fiber, and boron fiber. Among these, carbon fibers are preferably used because they have excellent characteristics of high strength and high elastic modulus while being lightweight.

  As the reinforcing fiber in the present invention, either a short fiber or a long fiber can be used. When emphasizing mechanical properties, it is preferable to use reinforcing fibers having a length of 10 cm or more because a fiber-reinforced composite material having excellent strength and elastic modulus can be obtained. On the other hand, when emphasizing formability, it is preferable to use reinforcing fibers having a length of 10 cm or less.

  Moreover, as for the content rate of the reinforced fiber in this invention, it is preferable that the fiber volume content rate is in the range of 30 to 80%, and it is more preferable that it is in the range of 40 to 80%. When high-modulus fiber such as glass fiber, carbon fiber, aramid fiber, alumina fiber, boron fiber is used as the reinforcing fiber, the elastic modulus in the fiber direction of the fiber-reinforced composite material is the elastic modulus of the reinforcing fiber itself and the reinforcing fiber. It is known that it is roughly proportional to the product of the content of. For this reason, when the fiber volume content is less than 40%, the elastic modulus of the obtained fiber-reinforced composite material may be insufficient, which is not preferable. On the other hand, if the fiber volume content is greater than 80%, the strength may decrease due to contact and abrasion between the reinforcing fibers, which is not preferable. Here, the fiber volume content is determined in accordance with ASTM D 3171-99.

The thermosetting resin in the present invention refers to a resin that forms a crosslinked structure by reaction and cures. Examples of thermosetting resins include unsaturated polyester resins, vinyl ester resins, epoxy resins, phenol resins, etc. The thermosetting resin composition in the present invention dramatically improves the impact resistance of fiber reinforced composite materials. Therefore, a cured product of a thermosetting resin composition having a tensile elastic modulus at 23 ° C. in the range of 0.001 to 1 GPa and a tensile elongation at break at 23 ° C. of 30% or more is used. is required. Further, a cured product of a thermosetting resin composition having a tensile elastic modulus at 23 ° C. in the range of 0.01 to 0.8 GPa and a tensile elongation at break at 23 ° C. of 40% or more is used. Preferably, the thermosetting resin composition has a tensile elastic modulus at 23 ° C. in the range of 0.02 to 0.6 GPa, and a tensile elongation at break at 23 ° C. of 50% or more. It is preferable to use a cured product. When the tensile modulus is higher than 1 GPa, the cured product of the thermosetting resin composition is not easily deformed, and is easily damaged when the impact load speed is high, and the impact resistance may be insufficient. On the other hand, if the tensile modulus is less than 0.001 GPa, the impact absorption energy due to deformation of the cured product of the thermosetting resin composition is small, and the impact resistance may be insufficient. On the other hand, if the tensile elongation at break is less than 30%, the cured product of the thermosetting resin composition is liable to be damaged at the time of impact load, and the impact resistance may be insufficient.

  In addition, the cured board of the thermosetting resin composition for measuring a tensile elasticity modulus and a tensile breaking elongation is produced as follows. A thermosetting resin composition is poured into a mold having a cavity with a thickness of 2 mm, and is cured under a predetermined curing condition in an oven to produce a resin plate. Here, the predetermined curing conditions refer to those equivalent to the curing conditions when molding the fiber-reinforced composite material. The method for obtaining the thermosetting resin composition may be adjusted by mixing each component of the thermosetting resin composition at a predetermined blending amount. If a prepreg is available, the thermosetting resin composition is thermoset. The functional resin composition may be taken out.

  Next, a small 1 (1/2) test piece of JIS K 7113-1995 was prepared from the cured plate of the thermosetting resin composition, and the tensile modulus and tensile elongation at break were based on JIS K 7113-1995. Measure the degree. For the measurement, 4201 type Tensilon manufactured by Instron or an equivalent device is used. The crosshead speed is 1.0 mm / min, and the measurement temperature is 23 ° C. The tensile elastic modulus is determined from the slope when the strain in the strain-stress curve is between 0.1% and 0.3%. Moreover, the strain at the time of fracture is measured with a gauge to determine the tensile elongation at break.

  Since the tensile modulus of the cured product of the thermosetting resin composition is moderately small and the tensile elongation at break is sufficiently large, the molecular weight α between the theoretical crosslinking points of the cured product of the thermosetting resin composition is 400. It is preferably within the range of ˜1600 g / mol, more preferably within the range of 500 to 1600 g / mol, and further preferably within the range of 600 to 1600 g / mol.

  Here, the molecular weight α between the theoretical cross-linking points is a value obtained by dividing the weight w of the entire resin cured product by the number c of the cross-linking points of the all resin cured product, and is inversely proportional to the crosslinking density of the resin cured product. . Further, the molecular weight α between the theoretical cross-linking points has a generally positive correlation with the elongation of the cured resin, and has a generally negative correlation with the resin elastic modulus. If the molecular weight α between the theoretical cross-linking points is less than 400 g / mol, the cross-linking density of the cured resin becomes too high, so that the tensile rupture elongation of the cured resin becomes small, and the resulting fiber-reinforced composite material has impact resistance. It may be insufficient and is not preferable. When the molecular weight α between the theoretical cross-linking points is larger than 1600 g / mol, the elastic modulus of the cured resin becomes small, and the resulting fiber-reinforced composite material may have insufficient impact resistance, which is not preferable.

  A method for obtaining the molecular weight α between the theoretical cross-linking points will be described below using an epoxy resin composition as an example.

First, in the case where k types (k is an integer) of epoxy resin components are included in the epoxy resin composition, the compounding amount of the i-th (i is an integer of 1 to k) epoxy resin component is selected as a _i (unit). : G). In addition, when the epoxy resin composition contains l type (l is an integer) curing agent component, the j-th (j is an integer of 1 to 1) of the curing agent is included in b _j (unit: Assuming g), the weight W (unit: g) of the entire resin cured product is obtained by the formula (1).

The epoxy equivalent of the i-th epoxy resin component is E _i (unit: g / mol), and the number of epoxy groups in one molecule of the i-th epoxy resin component is x _i . Further, the active hydrogen equivalent of the j-th curing agent component is H _j (unit: g / mol), and the number of active hydrogens possessed by one molecule of the j-th curing agent component is y _j . The number c (unit: mol) of crosslinking points contained in the cured resin is that the mixing ratio of the epoxy resin and the curing agent is stoichiometric, the curing agent is excessive, and the epoxy resin is excessive. The method of obtaining is different in the case of Which method is to be used is determined by the blending ratio index β, which represents the blending ratio of the epoxy resin and the curing agent, which is determined by the formula (2).

  Here, when β = 1, the compounding ratio of the epoxy resin and the curing agent is a stoichiometric amount, and the number c of cross-linking points is obtained by the formula (3). This number c of cross-linking points represents the number of cross-linking points generated by the reaction of all reactive epoxy groups with the active hydrogen of all curing agents.

  In the case of β> 1, the curing agent is in excess of the stoichiometric amount, and the number c of crosslinking points is obtained by the formula (4).

  In the case of β <1, the epoxy resin is in excess of the stoichiometric amount, and the number c of cross-linking points is obtained by the formula (5).

Here, E _i × x _i and H _j × y _j represent the average molecular weight of the i-th epoxy resin component and the average molecular weight of the j-th curing agent component, respectively. Further, (x _i -2) represents the number of cross-linking points generated when all the epoxy groups in one molecule of the i-th epoxy resin component react with the active hydrogen of the curing agent and are taken into the cross-linked structure. Further, (y _j -2) represents the number of crosslinking points generated by reacting all active hydrogens in one molecule of the j-th curing agent with an epoxy group and incorporating them into a crosslinked structure. For example, when the i-th epoxy resin component is a tetrafunctional epoxy resin, one molecule has four epoxy groups, and the number of cross-linking points generated is two, 4-2. In addition, when the j-th curing agent component has two active hydrogens per molecule, the number of cross-linking points generated is 0 (2-2). Dicyandiamide is assumed to be 7 functional and the number of cross-linking points generated is assumed to be 5 of 7-2.

  Using W and c obtained by the above-described formula, the molecular weight α between the crosslinking points is obtained by the formula (6).

  Here, as an example, epoxy resin 1 (epoxy group: 3, epoxy equivalent: 98 g / eq) 90 g, epoxy resin 2 (epoxy group: 2, epoxy equivalent: 135 g / eq) 10 g, and curing agent 1 (active The theoretical molecular weight α between the theoretical cross-linking points of the resin cured product of the epoxy resin composition comprising 4 pieces of hydrogen and 44.7 g of active hydrogen equivalent: 45 g / eq) is determined. First, the weight W of all resin hardened | cured material is 144.7g from Formula (1). Moreover, since β obtained from the equation (2) is 1, the number c of crosslinking points of all the cured resin products is obtained as 0.803 mol according to the equation (3). Therefore, the molecular weight α between the theoretical cross-linking points of the cured resin is determined as 180 g / mol according to the equation (6).

  In order for the tensile modulus of the cured product of the thermosetting resin composition to be moderately small and the tensile elongation at break to be sufficiently large, the thermosetting resin composition has a functional group equivalent in the range of 300 to 1000 g / mol. It is preferable to use the thermosetting resin as the main component, and more preferable to use the thermosetting resin as the main component in the range of functional group equivalent of 400 to 1000 g / mol. When the thermosetting resin having a functional group equivalent of less than 300 g / mol is the main component, the crosslink density of the cured product of the thermosetting resin composition becomes too large, and thus the tensile fracture of the cured product of the thermosetting resin composition. In some cases, the elongation decreases, and the resulting fiber-reinforced composite material has insufficient impact resistance. When the thermosetting resin having a functional group equivalent greater than 1000 g / mol is the main component, the crosslink density of the cured product of the thermosetting resin composition becomes too small, and hence the tensile strength of the cured product of the thermosetting resin composition The elastic modulus becomes small, and the resulting fiber-reinforced composite material may have insufficient impact resistance, which is not preferable. Here, the main component refers to occupying 60 wt% or more of all resin components in the thermosetting resin composition, and preferably occupying 80 wt% or more.

  Here, the functional group equivalent of the resin component is an equivalent per 1 mol of the curable functional group, and is obtained by dividing the average molecular weight of the resin component by the number of curable functional groups in one molecule. The functional group equivalent in the epoxy resin corresponds to the epoxy equivalent, and is obtained by dividing the average molecular weight of the epoxy resin by the number of epoxy groups in one molecule.

  Since the tensile modulus of the cured product of the thermosetting resin composition is moderately small, the thermosetting resin composition has a thermosetting property in which the number of aromatic rings contained in one molecule is in the range of 2 to 6. It is preferable to use a resin as a main component. If the thermosetting resin having less than 2 aromatic rings is the main component, the tensile modulus of the cured product of the thermosetting resin composition becomes too small, and the resulting fiber-reinforced composite material has insufficient impact resistance. This is not preferable. If the thermosetting resin having more than 6 aromatic rings is the main component, the tensile elastic modulus of the cured product of the thermosetting resin composition becomes too large, and the resulting fiber-reinforced composite material has impact resistance. It may be insufficient and is not preferable. Here, the main component refers to occupying 60 wt% or more of all resin components in the thermosetting resin composition, and preferably occupying 80 wt% or more.

  As the thermosetting resin in the present invention, an epoxy resin is preferably used because the balance between heat resistance and mechanical properties is particularly excellent.

  When using an epoxy resin as a thermosetting resin, it is preferable to use an epoxy resin as a main component. Here, the main component refers to occupying 60 wt% or more of all resin components in the thermosetting resin composition, and preferably occupying 80 wt% or more.

  Especially, in order that the tensile elasticity modulus of the hardened | cured material of a thermosetting resin composition is moderately small, and tensile elongation at break is sufficiently large, it selects from the epoxy resin which can be shown by following formula (I). It is preferable to include at least one epoxy resin.

  In the epoxy resin of the present invention, the following epoxy resins may be used in addition to the epoxy resin represented by the chemical formula (I).

  First, glycidyl ether type epoxy resin derived from polyol, glycidyl amine type epoxy resin derived from amine having multiple active hydrogens, glycidyl ester type epoxy resin derived from polycarboxylic acid, multiple double bonds in the molecule Examples thereof include an epoxy resin obtained by oxidizing a compound having the following.

  Examples of glycidyl ether type epoxy resins include bisphenol A, bisphenol F, bisphenol S, tetrabromobisphenol A, hexahydrobisphenol A, phenol novolac, cresol novolac, resorcinol, hydroquinone, 4,4′-dihydroxy-3,3 ′, 5. , 5′-tetramethylbiphenyl, 1,6-dihydroxynaphthalene, 9,9-bis (4-hydroxyphenyl) fluorene, tris (p-hydroxyphenyl) methane, tetrakis (p-hydroxyphenyl) ethane, 1,6- Polyols such as hexanediol, neopentylene glycol, propylene glycol, polypropylene glycol, sorbitol, trimethylolpropane, glycerin, diglycerin, polyglycerin, castor oil A glycidyl ether obtained by reacting epichlorohydrin is preferably used.

  Examples of the glycidylamine type epoxy resin include 4,4′-diaminodiphenylmethane, m-xylylenediamine, 1,3-bis (aminomethyl) cyclohexane, aniline, toluidine, 9,9-bis (4-aminophenyl) fluorene, and the like. Glycidylamine obtained by reacting with chloroepiline is preferably used.

  Furthermore, epoxy resins obtained by reacting both hydroxyl groups and amino groups of aminophenols such as m-aminophenol, p-aminophenol and 4-amino-3-methylphenol with epichlorohydrin are also preferably used. .

  As the glycidyl ester type epoxy resin, a glycidyl ester obtained by reacting phthalic acid, terephthalic acid, hexahydrophthalic acid, dimer acid or the like with epichlorohydrin is preferably used.

  Examples of the epoxy resin obtained by oxidizing a compound having a plurality of double bonds in the molecule include an epoxy resin having an epoxycyclohexane ring in the molecule. Further, examples of the epoxy resin include epoxidized soybean oil.

  Besides these, an epoxy resin such as triglycidyl isocyanurate is preferably used.

  Furthermore, an epoxy resin synthesized from the above-mentioned epoxy resin as a raw material, for example, an epoxy resin synthesized from a bisphenol A diglycidyl ether and tolylene diisocyanate by an oxazolidone ring formation reaction is also preferably used.

  When an epoxy resin is used as the matrix resin used in the present invention, it is used in combination with a curing agent. The curing agent may be a compound having an active group that reacts with the epoxy group of the epoxy resin, and specific examples thereof include polyamines, acid anhydrides, phenols, and mercaptans. In addition, basic compounds such as tertiary amines and imidazoles, which are initiators for homopolymerization of epoxy resins, or acidic compounds such as amine complexes of boron trifluoride can also be used.

  In addition, the matrix resin used in the present invention includes other components such as polyamide, polyamideimide, polycarbonate, polysulfone, polyacetal, polyphenylene ether, polyphenylene sulfide, polyarylate, polyetherimide, polyethersulfone, and polyetherketone. It is also possible to modify by mixing a plastic resin, inorganic fine particles such as fine powdered silica, and an elastomer.

  Moreover, it is preferable that the thermosetting resin composition of this invention does not contain substantially solvents, such as acetone, methyl ethyl ketone, methanol, ethanol, toluene, xylene. When these solvents are contained in the thermosetting resin composition, voids are generated in the fiber reinforced composite material, and the strength of the fiber reinforced composite material may be significantly reduced. Here, “substantially free of solvent” means that the proportion of the solvent in the total thermosetting resin composition is 1 wt% or less, preferably 0.5 wt% or less. The proportion of the solvent in the total thermosetting resin composition can be measured by the following method. That is, the thermosetting resin composition is poured into an aluminum cup having a diameter of 5 cm so as to have a thickness of 1 mm. Next, it is left in an oven set at 100 ° C. for 30 minutes. The ratio of the solvent in the thermosetting resin composition is calculated from the ratio between the weight of the thermosetting resin composition before being left in the oven and the decrease in weight when left in the oven.

  Next, the prepreg of the present invention will be described.

  The prepreg in the present invention means a sheet-like intermediate base material in which reinforcing fibers are impregnated with a thermosetting resin composition.

  As the reinforcing fiber used in the prepreg of the present invention, various fibers can be used, but since a high-strength fiber-reinforced composite material is obtained, the tensile strength of the reinforcing fiber is preferably 1500 MPa or more, and 3500 MPa or more. It is more preferable that it is 4500 MPa or more. In addition, since a fiber-reinforced composite material having a high elastic modulus can be obtained, the tensile elastic modulus of the reinforcing fiber is preferably 100 GPa or more, more preferably 200 GPa or more, and further preferably 250 GPa or more. Specific examples of the reinforcing fiber include glass fiber, carbon fiber, aramid fiber, alumina fiber, and boron fiber. Among these, carbon fibers are preferably used because they have excellent characteristics of high strength and high elastic modulus while being lightweight.

  The form of the reinforcing fiber used in the prepreg of the present invention may be a form in which reinforcing fibers are arranged in one direction, a woven form, a knitted form, or a form in which reinforcing fibers such as a nonwoven fabric and a mat are randomly arranged. good. Especially, since the fiber reinforced composite material of high intensity | strength and a high elastic modulus is obtained, it is preferable to have the form which arranged the reinforced fiber in one direction.

Fiber weight per unit area of the prepreg of the present invention is preferably 40~250g / ^{m 2,} and more preferably 50 to 200 g / ^{m 2.} If the fiber weight per unit area is less than 40 g / m ² , the shape retention of the prepreg may be reduced and it may be difficult to handle. If the fiber weight per unit area is larger than 250 g / m ² , the fiber alignment inside the prepreg is likely to be disturbed, and a high-performance fiber-reinforced composite material may not be obtained.

  As the matrix resin used in the prepreg of the present invention, the matrix resin used in the above-described fiber-reinforced composite material can be used as it is.

  Next, the manufacturing method of the fiber reinforced composite material of this invention is demonstrated.

  When manufacturing a fiber reinforced composite material using the prepreg of this invention, it is performed in the following ways, for example. After laminating the pattern obtained by cutting the prepreg, the fiber reinforced composite material is obtained by heat curing the thermosetting resin while applying pressure to the laminate. As a method for applying heat and pressure, press molding, autoclave molding, vacuum pressure molding, sheet winding method, and internal pressure molding method are preferably used.

  Moreover, when manufacturing a fiber reinforced composite material without using a prepreg, any manufacturing method of the conventionally known fiber reinforced composite material can be used.

  For example, when using a sheet molding compound (SMC), it can be manufactured by the following procedure. First, SMC is laminated on the press device. Next, it is cured while being heated and pressurized to produce a fiber reinforced composite material.

  For example, when the resin transfer molding (RTM) method is used, it can be manufactured by the following procedure. First, reinforcing fibers such as a woven form and a knitted form are placed in a mold. The mold is closed, and a liquid thermosetting resin composition is impregnated into the reinforcing fiber and then cured to produce a fiber-reinforced composite material.

  In the fiber-reinforced composite material of the present invention, a part or all of the matrix resin has a tensile modulus measured at 23 ° C. within a range of 0.001 to 1 GPa and a tensile measured at 23 ° C. It is necessary to be a cured product of a thermosetting resin composition having a breaking elongation of 30% or more. Here, a part or the whole indicates that the thermosetting resin composition occupies 5 wt% or more of the entire matrix resin. However, it is preferable that the thermosetting resin composition occupies 15 wt% or more of the total matrix resin, and more preferable that the thermosetting resin composition occupies 35 wt% or more. Further, in the fiber reinforced composite material, there is no particular limitation on the arrangement of the thermosetting resin composition, but the fiber reinforced composite material is concentrated in a specific position in the thickness direction of the fiber strong composite material or specified in the plane direction. A method of concentrating and arranging in a place is possible.

Since the fiber-reinforced composite material of the present invention can reduce the weight of the member, the tensile strength in the fiber direction, that is, the 0 ° tensile strength is preferably 600 MPa or more, more preferably 1800 MPa or more, Furthermore, it is preferable that it is 2400 MPa or more.
Moreover, since the fiber-reinforced composite material of the present invention can reduce the weight of the member, the tensile elastic modulus in the fiber direction, that is, the 0 ° tensile elastic modulus is preferably 40 GPa or more, and 120 GPa or more. Is more preferable, and more preferably 160 GPa or more.

  Here, the 0 ° tensile strength and the 0 ° tensile elastic modulus are measured according to ASTM D 3039-93. For the measurement, 4208 type Tensilon manufactured by Instron or an equivalent apparatus is used. The crosshead speed is 1.27 mm / min and the measurement temperature is 23 ° C. The 0 ° tensile elastic modulus is determined from the slope when the strain in the strain-stress curve is between 0.1% and 0.6%.

  The fiber-reinforced composite material of the present invention is lightweight, excellent in mechanical properties such as strength and elastic modulus, and excellent in impact resistance. Therefore, it can be widely used in aircraft space applications, sports equipment applications, automobile applications, and the like. .

Hereinafter, the present invention will be described specifically by way of examples. The materials used in Examples and Comparative Examples are as follows.
Reinforcing fiber, reinforcing fiber fabric The following two types were used for the reinforcing fiber of the present invention, and the following one type was used for the reinforcing fiber fabric.
・ Carbon fiber “Torayca” T800H:
Registered trademark, manufactured by Toray Industries, Inc., 12,000 filaments,
Tensile strength 5490 MPa, tensile elastic modulus 294 GPa
・ Aramid fiber "Kevlar" 49:
Registered trademark, manufactured by Toray DuPont Co., Ltd., 768 filaments,
Tensile strength 3000 MPa, tensile modulus 112 GPa, carbon fiber fabric CO6343B:
No., “Torayca” T300 manufactured by Toray Industries, Inc., plain weave, 198 g / m ²
Thermosetting resin composition The following resin component, curing agent, curing accelerator, and thermoplastic resin were used as components of the thermosetting resin composition of the present invention.
(Resin component)
EXA-4850-150:
Epoxy resin represented by chemical formula (II) manufactured by Dainippon Ink Co., Ltd.

・ "Epiclon" TSR-601:
Epoxy resin represented by chemical formula (III), registered trademark, Dainippon Ink Co., Ltd.

・ "Denacol" EX-841:
Epoxy resin represented by chemical formula (IV), registered trademark, manufactured by Nagase ChemteX Corporation

・ "Epicoat" 828:
Registered trademark, Japan Epoxy Resin Co., Ltd. bisphenol A type epoxy resin, epoxy equivalent is 189 g / mol, and the number of aromatic rings contained in the molecule is 2.2.
"Epicoat" 1004:
Registered trademark, Japan Epoxy Resin Co., Ltd. bisphenol A type epoxy resin, epoxy equivalent is 925 g / mol, and the number of aromatic rings contained in the molecule is twelve.
・ "Elisys" GE-20
Registered trademark, manufactured by PTI Japan
Neopentyl glycol diglycidyl ether, epoxy equivalent is 135 g / mol, and the number of aromatic rings contained in the molecule is zero.
(Curing agent)
・ Dicy7:
Part number, Japan Epoxy Resin Co., Ltd. Dicyandiamide (curing accelerator)
DCMU99:
No., manufactured by Hodogaya Chemical Co., Ltd. 3- (3,4-dichlorophenyl) -1,1-dimethylurea (thermoplastic resin)
・ "Matsumoto Microsphere" M:
Registered trademark, manufactured by Matsumoto Yushi Co., Ltd. Polymethylmethacrylate Next, preparation of thermosetting resin composition, preparation of cured plate of thermosetting resin composition, production of fiber reinforced composite material, measurement methods of various physical properties are as follows: Shown in
1. Adjustment of resin composition for prepreg The resin composition for prepreg was adjusted by the following procedure with the compounding ratios shown in Tables 1 and 2. A kneader was used for mixing each component. In addition, the numerical value in a table | surface shows a weight part.
(1) The resin component was put into a kneader and mixed at 40 ° C. for 30 minutes.
(2) The thermoplastic resin was put into a kneader, heated to 170 ° C., and then mixed at 170 ° C. for 60 minutes.
(3) After the temperature was lowered to 60 ° C., a curing agent and a curing accelerator were added to the kneader and mixed at 60 ° C. for 30 minutes.
2. Adjustment of the resin composition for RTMs By the mixture ratio shown in Table 4, each component was thrown into the disposable cup made from polyethylene, it mixed using the spatula, and the resin composition for RTMs was adjusted. In addition, the numerical value in a table | surface shows a weight part.
3. Preparation of cured plate of resin composition for prepreg A cured plate of a resin composition for prepreg was prepared by the following procedure.

(1) The resin composition for prepreg was heated to 80 ° C. and degassed for about 20 minutes in a separable flask directly connected to a vacuum pump.
(2) The resin composition for prepreg was poured into a mold having a cavity of 12 cm × 20 cm × 2 mm (thickness).

  (3) The mold was set in an oven and cured by heating at 135 ° C. for 2 hours.

(4) After cooling, the cured plate of the resin composition for prepreg was removed from the mold.
4). Preparation of Cured Plate of RTM Resin Composition A cured plate of RTM resin composition was prepared by the following procedure.
(1) The RTM resin composition was heated to 40 ° C. and defoamed in a separable flask directly connected to a vacuum pump for about 5 minutes.
(2) The resin composition for RTM was poured into a mold having a cavity of 12 cm × 20 cm × 2 mm (thickness).

  (3) The mold was set in an oven and cured by heating at 100 ° C. for 2 hours.

(4) After cooling, the cured plate of the resin composition for RTM was removed from the mold.
5. Preparation of fiber reinforced composite material by prepreg / autoclave method The resin composition for prepreg was applied onto release paper using a reverse roll coater to prepare a resin film. A resin film was stacked on both side surfaces of the reinforcing fibers aligned in one direction, and heated and pressurized (130 ° C., 0.4 MPa) to impregnate the reinforcing fibers with the resin composition for prepreg to prepare a prepreg. The fiber weight per unit area of the prepreg was 125 g / m ² and the fiber volume content was 65%.

  Next, 10 ply of the prepreg cut so as to be a square with a side of 30 cm is laminated in the fiber direction, that is, in the 0 ° direction, bagged with a nylon film on a stainless steel tool plate, and then heated and pressurized using an autoclave. (135 ° C., 0.6 MPa, 2 hours) to cure the resin composition for prepreg and prepare a fiber-reinforced composite material for a tensile test.

In addition, after prepregs cut so as to be a square of 30 cm on a side, 3 ply in 0 ° direction, 4 ply in 90 ° direction, 3 ply in 0 ° direction, and bagging with a nylon film on a stainless steel tool plate, By applying heat and pressure (135 ° C., 0.6 MPa, 2 hours) using an autoclave, the resin composition for prepreg was cured, and a fiber-reinforced composite material for impact penetration test was produced.
6). Fabrication of fiber reinforced composite material by RTM method Carbon fiber fabric CO6343B, 10ply cut so that each side is a square of 30cm on one side parallel to either warp or weft, is laminated in a mold, and peel ply and resin distribution medium on it A polyester net which is Next, bagging was performed using a nylon film, and the pressure was reduced to [atmospheric pressure-0.1] (MPa) using a vacuum pump. Then, the mold was held at 100 ° C., and an RTM resin composition was injected. The injection was completed 5 minutes after the RTM resin composition flowed into the mold, and the mold was removed 2 hours after the RTM resin composition flowed into the mold, for tensile testing and impact penetration testing. A fiber reinforced composite material was prepared.
7). Tensile test of cured product of resin composition From the cured plate of the resin composition obtained by the above method, a small size 1 (1/2) test piece of JIS K 7113-1995 was prepared and conformed to JIS K 7113-1995. Then, the tensile strength, the tensile elastic modulus, and the tensile elongation at break were measured. As the measuring apparatus, 4201 type Tensilon manufactured by Instron was used. Here, the crosshead speed was 1.0 mm / min, and the measurement temperature was 23 ° C. The results are shown in Tables 1-4.

8). Measurement of Fiber Volume Content of Fiber Reinforced Composite Material The fiber volume content was determined according to ASTM D 3171-99. The results are shown in Tables 1-4.

9. 0 ° tensile test of fiber reinforced composite material From the fiber reinforced composite material obtained by the above method, a test piece having a width of 12.7 mm and a length of 229 mm was prepared so that the 0 ° direction and the length direction were the same. Based on ASTM D 3039-93, 0 ° tensile strength and 0 ° tensile elastic modulus were measured. The measuring device used was Instron 4208 type Tensilon. Here, the crosshead speed was 1.27 mm / min, and the measurement temperature was 23 ° C. The 0 ° tensile elastic modulus is determined from the slope when the strain in the strain-stress curve is between 0.1% and 0.3%. The results are shown in Tables 1-4.
10. Impact Penetration Test of Fiber Reinforced Composite Material A test piece having a width of 100 mm and a length of 150 mm is prepared from the fiber reinforced composite material obtained by the above method so that the 0 ° direction and the length direction are the same, and the weight is 2. When a falling weight of 5 kg and a diameter of 12.5 mm was dropped from a predetermined initial height, the damage condition of the fiber reinforced composite material was observed with the naked eye, and the impact penetration resistance of the fiber reinforced composite material was examined. As the measuring device, Dyna Tap 8250 type manufactured by Instron was used, and the initial height of the falling weight was three types of 10 cm, 20 cm, and 30 cm. The results are shown in Tables 1 to 4, where x is the case where the falling weight penetrates the fiber-reinforced composite material, and ○ is the case where the falling weight does not penetrate.
Example 1
A prepreg was prepared using the epoxy resin composition shown in Table 1, and various measurements were performed. The epoxy resin composition of Example 1 is mainly composed of EXA-4850-150, which is an epoxy resin having an appropriately long space between epoxy groups and an appropriate rigidity. The molecular weight between the theoretical crosslinking points is 639 g / mol, which is reasonably large. As a result of the measurement, the tensile modulus of the cured product of the thermosetting resin composition at 23 ° C. is reasonably small as 0.22 GPa, and the tensile elongation at break of the cured product of the thermosetting resin composition at 23 ° C. is 71. % And big enough. The fiber-reinforced composite material using carbon fibers as the reinforcing fibers had a sufficiently large 0 ° tensile strength of 2330 MPa and a 0 ° tensile elastic modulus of 175 GPa, and the results of the impact resistance test were also very good.
(Example 2)
Using the epoxy resin of Example 1, a prepreg having an aramid fiber as a reinforcing fiber was prepared, and various measurements were performed. As a result of the measurement, the fiber reinforced composite material had a relatively high 0 ° tensile strength of 1130 MPa and a 0 ° tensile elastic modulus of 99 GPa. Furthermore, the results of the impact resistance test were also very good.
(Example 3)
A prepreg was prepared using the epoxy resin composition shown in Table 1, and various measurements were performed. The epoxy resin composition of Example 3 contains 90 parts by weight of EXA-4850-150, which is an epoxy resin having an appropriately long space between epoxy groups and an appropriate rigidity, and includes, as a main component, 10 parts by weight of “Epicoat” 828, which is an epoxy resin between epoxy groups is short. The molecular weight between theoretical cross-link points is 577 g / mol, which is smaller than Example 1. As a result of the measurement, the tensile modulus of the cured product of the thermosetting resin composition at 23 ° C. is reasonably small as 0.45 GPa, and the tensile elongation at break of the cured product of the thermosetting resin composition at 23 ° C. is 53. % Was relatively large. The fiber-reinforced composite material using carbon fibers as reinforcing fibers had a sufficiently high 0 ° tensile strength of 2380 MPa and a 0 ° tensile elastic modulus of 175 GPa, and the results of the impact resistance test were relatively good.
Example 4
A prepreg was prepared using the epoxy resin composition shown in Table 1, and various measurements were performed. The epoxy resin composition of Example 4 contains 70 parts by weight of EXA-4850-150, which is an epoxy resin having a moderately long space between epoxy groups and moderate rigidity, and in addition, 30 parts by weight of “Epicoat” 828, which is an epoxy resin between epoxy groups is short The molecular weight between the theoretical crosslinking points is 459 g / mol, which is smaller than those in Examples 1 and 2. As a result of the measurement, the tensile elastic modulus of the thermosetting resin composition at 23 ° C. was moderately small as 0.99 GPa, and the tensile breaking elongation of the thermosetting resin composition at 23 ° C. was slightly large as 35%. The fiber-reinforced composite material using carbon fibers as the reinforcing fibers had a sufficiently high 0 ° tensile strength of 2430 MPa and a 0 ° tensile elastic modulus of 178 GPa, and the results of the impact resistance test were also somewhat good.
(Example 5)
A prepreg was prepared using the epoxy resin composition shown in Table 1, and various measurements were performed. The epoxy resin composition of Example 5 contains 90 parts by weight of EXA-4850-150, which is an epoxy resin having a moderately long space between epoxy groups and a moderate rigidity, and includes, as a main component, 10 parts by weight of “Epicoat” 1004, which is an epoxy resin having an excessively rigid skeleton, although the space between the epoxy groups is moderately long. The molecular weight between the theoretical crosslinking points is 689 g / mol, which is reasonably large. As a result of the measurement, the tensile elastic modulus of the thermosetting resin composition at 23 ° C. was reasonably small as 0.38 GPa, and the tensile breaking elongation of the thermosetting resin composition at 23 ° C. was relatively large as 60%. . The fiber reinforced composite material using carbon fibers as the reinforcing fibers had a sufficiently high 0 ° tensile strength of 2310 MPa and a 0 ° tensile elastic modulus of 175 GPa, and the results of the impact resistance test were relatively good.
(Example 6)
A prepreg was prepared using the epoxy resin composition shown in Table 1, and various measurements were performed. The epoxy resin composition of Example 6 contains 70 parts by weight of EXA-4850-150, which is an epoxy resin having a moderately long space between epoxy groups and moderate rigidity, and is composed mainly of 30 parts by weight of “Epicoat” 1004, which is an epoxy resin having an excessively rigid skeleton, although the space between the epoxy groups is moderately long. The molecular weight between the theoretical crosslinking points is 747 g / mol, which is reasonably large. As a result of the measurement, the tensile elastic modulus of the thermosetting resin composition at 23 ° C. is moderately small as 0.78 GPa, and the tensile elongation at break of the cured product of the thermosetting resin composition at 23 ° C. is compared with 42%. It was big. The fiber-reinforced composite material using carbon fibers as the reinforcing fibers had a sufficiently high 0 ° tensile strength of 2390 MPa and a 0 ° tensile elastic modulus of 178 GPa, and the results of the impact resistance test were relatively good.
(Example 7)
A prepreg was prepared using the epoxy resin composition shown in Table 2, and various measurements were performed. The epoxy resin composition of Example 7 contains “Epiclon” TSR-601, which is an epoxy resin having a reasonably long space between epoxy groups and moderate rigidity. The molecular weight between the theoretical crosslinking points is 689 g / mol, which is reasonably large. As a result of the measurement, the tensile elastic modulus of the thermosetting resin composition at 23 ° C. was reasonably small as 0.040 GPa, and the tensile breaking elongation of the thermosetting resin composition at 23 ° C. was sufficiently large as 55%. . The fiber-reinforced composite material using carbon fibers as the reinforcing fibers had a sufficiently high 0 ° tensile strength of 2260 MPa and a 0 ° tensile elastic modulus of 170 GPa, and the results of the impact resistance test were relatively good.
(Example 8)
A prepreg was prepared using the epoxy resin composition shown in Table 2, and various measurements were performed. The epoxy resin composition of Example 8 includes “Denacol” EX-841, which is an epoxy resin having an excessively flexible skeleton, although the distance between the epoxy groups is moderately long. The molecular weight between the theoretical crosslinking points is 542 g / mol, which is reasonably large. As a result of the measurement, the tensile elastic modulus of the thermosetting resin composition at 23 ° C. was reasonably small as 0.015 GPa, and the tensile breaking elongation of the thermosetting resin composition at 23 ° C. was sufficiently large as 40%. . The fiber-reinforced composite material using carbon fibers as the reinforcing fibers had a sufficiently high 0 ° tensile strength of 2020 MPa and a 0 ° tensile elastic modulus of 165 GPa, and the results of the impact resistance test were also somewhat good.
(Comparative Example 1)
A prepreg was prepared using the epoxy resin composition shown in Table 2, and various measurements were performed. The epoxy resin composition of Comparative Example 1 includes “Epicoat” 828, which is an epoxy resin having short epoxy groups. The molecular weight between the theoretical crosslinking points is 283 g / mol, which is small. As a result of the measurement, the tensile modulus of the thermosetting resin composition at 23 ° C. was excessively large as 3.3 GPa, and the tensile elongation at break of the thermosetting resin composition at 23 ° C. was as small as 6%. Although the fiber reinforced composite material using carbon fiber as the reinforcing fiber has a sufficiently high 0 ° tensile strength of 2550 MPa and a 0 ° tensile elastic modulus of 180 GPa, the result of the impact resistance test was not excellent.
(Comparative Example 2)
A prepreg was prepared using the epoxy resin composition shown in Table 2, and various measurements were performed. The epoxy resin composition of Comparative Example 2 contains 50 parts by weight of “Epicoat” 828, which is an epoxy resin having a short distance between epoxy groups. "Contains 50 parts by weight of 1004." The molecular weight between the theoretical crosslinking points is 459 g / mol, which is reasonably large. As a result of the measurement, the tensile modulus of the thermosetting resin composition at 23 ° C. was excessively large as 3.1 GPa, and the tensile elongation at break of the thermosetting resin composition at 23 ° C. was as small as 8%. Although the fiber reinforced composite material using carbon fiber as the reinforced fiber has a sufficiently high 0 ° tensile strength of 2600 MPa and a 0 ° tensile elastic modulus of 179 GPa, the result of the impact resistance test was not excellent.
(Comparative Example 3)
A prepreg was prepared using the epoxy resin composition shown in Table 2, and various measurements were performed. The epoxy resin composition of Comparative Example 3 contains 50 parts by weight of “Epicoat” 828, which is an epoxy resin having short epoxy groups, and in addition, “Elysis” GE—having an excessively flexible skeleton with short epoxy groups. 20 parts by weight are included. The molecular weight between the theoretical cross-linking points is as small as 169 g / mol. As a result of the measurement, the resin tensile modulus at 23 ° C. was excessively large as 1.2 GPa, and the resin breaking elongation at 23 ° C. was as small as 15%. Although the fiber reinforced composite material using carbon fiber as the reinforcing fiber has a sufficiently high 0 ° tensile strength of 2530 MPa and a 0 ° tensile elastic modulus of 177 GPa, the result of the impact resistance test was not excellent.

Example 9
As shown in Table 3, a fiber reinforced composite material was prepared using two types of prepregs of the prepreg of Example 1 and the prepreg of Comparative Example 2, and various measurements were performed. For tensile measurement, the prepreg of Comparative Example 2 was laminated at 3 ply in the 0 ° direction, the prepreg of Example 1 was laminated at 4 ply in the 0 ° direction, and the prepreg of Comparative Example 2 was laminated at 3 ply in the 0 ° direction. For the impact resistance test, the prepreg of Comparative Example 2 was laminated at 3 ply in the 0 ° direction, the prepreg of Example 1 was laminated at 4 ply in the 90 ° direction, and the prepreg of Comparative Example 2 was laminated at 3 ply in the 0 ° direction. As a result of the measurement, the fiber reinforced composite material using carbon fiber as the reinforcing fiber has a sufficiently large 0 ° tensile strength of 2620 MPa and a 0 ° tensile elastic modulus of 180 GPa, and furthermore, the result of the impact resistance test is extremely good. I understood.
(Example 10)
As shown in Table 3, various measurements were performed in the same manner as in Example 9, except that the prepreg of Example 1 was changed to the prepreg of Example 7. As a result of the measurement, the fiber-reinforced composite material using carbon fiber as the reinforcing fiber has a sufficiently high 0 ° tensile strength of 2530 MPa and a 0 ° tensile elastic modulus of 178 GPa, and the impact resistance test result is relatively good. I understood it.

(Example 11)
Using the epoxy resin composition shown in Table 4, a fiber reinforced composite material was prepared by the RTM method, and various measurements were performed. The epoxy resin composition of Example 11 includes EXA-4850-150, which is an epoxy resin having a reasonably long space between epoxy groups and moderate rigidity. The molecular weight between the theoretical crosslinking points is 1015 g / mol, which is reasonably large. As a result of the measurement, the tensile elastic modulus of the cured product of the thermosetting resin composition at 23 ° C. is reasonably small as 0.063 GPa, and the tensile elongation at break of the thermosetting resin composition at 23 ° C. is sufficiently high at 82%. It was big. The fiber reinforced composite material using carbon fibers as the reinforcing fibers had a sufficiently high 0 ° tensile strength of 780 MPa and a 0 ° tensile elastic modulus of 61 GPa, and the results of the impact resistance test were also very good.
(Comparative Example 4)
Using the epoxy resin composition shown in Table 4, a fiber reinforced composite material was prepared by the RTM method, and various measurements were performed. The epoxy resin composition of Comparative Example 4 includes “Epicoat” 828, which is an epoxy resin having short epoxy groups. The molecular weight between the theoretical crosslinking points is 494 g / mol, which is reasonably large. As a result of the measurement, the tensile elastic modulus of the thermosetting resin composition at 23 ° C. was excessively large as 2.6 GPa, and the tensile elongation at break of the thermosetting resin composition at 23 ° C. was as small as 8%. Although the fiber reinforced composite material using carbon fibers as the reinforcing fibers has a sufficiently high 0 ° tensile strength of 790 MPa and a 0 ° tensile elastic modulus of 63 GPa, the results of the impact resistance test were not excellent.

  The fiber-reinforced composite material of the present invention is lightweight, excellent in mechanical properties such as strength and elastic modulus, and excellent in impact resistance. Therefore, it can be widely used in aircraft space applications, sports equipment applications, automobile applications, and the like. .

Claims (18)

  Tensile strength includes a reinforcing fiber and a matrix resin, and part or all of the matrix resin has a tensile modulus measured at 23 ° C. within a range of 0.001 to 1 GPa and is measured at 23 ° C. A fiber-reinforced composite material which is a cured product of a thermosetting resin composition having a breaking elongation of 30% or more.   The fiber reinforced composite material according to claim 1, wherein the reinforcing fiber is at least one selected from glass fiber, carbon fiber, aramid fiber, alumina fiber, and boron fiber.   The fiber-reinforced composite material according to any one of claims 1 and 2, wherein the volume content of the reinforcing fibers is within a range of 30 to 80%.   The fiber reinforced composite material according to any one of claims 1 to 3, wherein the molecular weight α between theoretical crosslink points of the cured product of the thermosetting resin composition is in the range of 400 to 1600 g / mol.   The thermosetting resin composition includes a resin component having a functional group equivalent in a range of 300 to 1000 g / mol, and the resin component is a main component. Fiber reinforced composite material.   The thermosetting resin composition contains a resin component having 2 to 6 aromatic rings in one molecule, and the resin component is a main component. The fiber-reinforced composite material according to any one of the above.   The fiber reinforced composite material according to claim 1, wherein the thermosetting resin composition contains an epoxy resin. The fiber-reinforced composite material according to claim 7, wherein the thermosetting resin composition contains at least one epoxy resin selected from epoxy resins that can be represented by the following formula (I).

  The fiber-reinforced composite material according to claim 1, wherein the 0 ° tensile strength measured at 23 ° C. is 600 MPa or more.   The fiber-reinforced composite material according to claim 1, wherein a 0 ° tensile elastic modulus measured at 23 ° C. is 40 GPa or more.   A thermosetting resin composition having a tensile elastic modulus measured at 23 ° C. within a range of 0.001 to 1 GPa and a tensile elongation at break measured at 23 ° C. of 30% or more is used as a reinforcing fiber. A prepreg made by impregnation.   The prepreg according to claim 11, wherein the reinforcing fiber is at least one selected from glass fiber, carbon fiber, aramid fiber, alumina fiber, and boron fiber.   The prepreg according to any one of claims 11 and 12, wherein a volume content of the reinforcing fibers is in a range of 30 to 80%.   The prepreg according to any one of claims 11 to 13, wherein the molecular weight α between theoretical cross-linking points of the cured product of the thermosetting resin composition is in the range of 400 to 1600 g / mol.   The thermosetting resin composition includes a resin component having a functional group equivalent in a range of 300 to 1000 g / mol, and the resin component is a main component. Prepreg.   The thermosetting resin composition contains a resin component in which the number of aromatic rings contained in one molecule is in the range of 2 to 6, and the resin component is a main component. The prepreg according to any one of the above.   The prepreg according to any one of claims 11 to 16, wherein the thermosetting resin composition contains an epoxy resin. The prepreg according to claim 17, wherein the thermosetting resin composition contains at least one epoxy resin selected from epoxy resins that can be represented by the following formula (I).