JP7338130B2 - Epoxy resin composition and prepreg for fiber reinforced composites - Google Patents

Description

TECHNICAL FIELD The present invention relates to an epoxy resin composition used for a prepreg for fiber-reinforced composite materials, and a prepreg for fiber-reinforced composite materials using the epoxy resin composition.

Fiber reinforced composite materials consisting of reinforcing fibers and matrix resins are lightweight and have excellent mechanical properties. Widely used for various purposes. A fiber-reinforced composite material is obtained by thermoforming a prepreg for a fiber-reinforced composite material, which is an intermediate material.

A prepreg is a reinforcing fiber impregnated with a thermosetting resin or a thermoplastic resin. Thermosetting resins are mainly used as resins for prepregs because of the heat resistance and strength of fiber-reinforced composite materials. Epoxy resins are most often used because of the availability of the materials. In particular, in applications requiring heat resistance such as aerospace applications and industrial applications, 180° C. curing type epoxy resins are often used.

However, a general 180° C. curing type epoxy resin requires heating at 180° C. for 2 hours or more for curing. Therefore, (i) the heating furnace used to mold the prepreg must have a sufficient heating capacity, (ii) the molding time will be longer, and (iii) the auxiliary materials are required to have the same degree of heat resistance. There is a problem that the manufacturing cost of the reinforced composite material becomes high.

As a method for solving this problem, for example, a method is known in which an epoxy resin composition is primarily cured at a low temperature of 80 to 140° C., demolded, and then post-cured at a high temperature of 180° C. or higher (Patent Document 1). reference). An epoxy resin composition that can be completely cured at 150° C. for 60 minutes has also been proposed (see Patent Document 2).

Japanese Patent No. 4396274 Japanese Patent No. 5326435

However, as described in Patent Document 1, in the case of a method that combines primary curing at a low temperature and post-curing at a high temperature, two molding and curing processes are required. It has a problem of high cost.
Moreover, the epoxy resin composition described in Patent Document 2 requires heating for 60 minutes at a low temperature of 150° C., and the manufacturing cost is still high. Furthermore, it is difficult for the resulting cured product to achieve the heat resistance (specifically, a glass transition point of 180° C. or higher) required in the fields of aerospace, automobiles, bicycles, and the like.

The present invention provides an epoxy resin composition which is excellent in heat resistance and elastic modulus of the cured product, elastic modulus retention in a high temperature range, and mechanical properties in spite of having low-temperature and high-speed curability, and the epoxy resin composition. The present invention provides a prepreg for fiber-reinforced composite material using the present invention.

・・・式（１）
（２） 前記成分（Ａ）と前記成分（Ｂ）の割合が質量比で３０：７０～４０：６０である、上記（１）に記載のエポキシ樹脂組成物。
（３） 更に、下記成分（Ｄ）を含む、上記（１）または（２）に記載のエポキシ樹脂組成物。
（Ｄ）成分：熱可塑性樹脂
（４） １５０℃で３０分間加熱して得られる硬化物の動的粘弾性試験におけるガラス転移温度が１８０℃以上である、上記（１）から（３）のいずれかに記載のエポキシ樹脂組成物。
（５） １５０℃で３０分間加熱して得られる硬化物の動的粘弾性試験における３５℃での貯蔵弾性率が２，９００ＭＰａ以上、１５０℃での貯蔵弾性率が２，０００ＭＰａ以上である、上記（１）から（４）のいずれかに記載のエポキシ樹脂組成物。
（６） １５０℃で３０分間加熱して得られる硬化物の示差走査熱量測定における反応発熱ピークの半値幅が１２℃以下である、上記（１）から（５）のいずれかに記載のエポキシ樹脂組成物。
（７） 強化繊維とマトリクス樹脂を含むプリプレグであって、マトリクス樹脂が下記（Ａ）成分、（Ｂ）成分および（Ｃ）成分を含んでなるエポキシ樹脂組成物であるプリプレグ。
（Ａ）成分：一分子内に少なくとも３つのグリシジル基を有するグリシジルアミン型エポキシ樹脂
（Ｂ）成分：分子内にオキサゾリドン環を有するエポキシ樹脂（Ｂ）
（Ｃ）成分：式（１）で表されるイミダゾール化合物（Ｃ）

・・・式（１）
（８） 前記成分（Ａ）と前記成分（Ｂ）の割合が質量比で３０：７０～４０：６０である、上記（７）に記載のプリプレグ。
（９） 前記マトリクス樹脂が更に下記成分（Ｄ）を含む、上記（７）または（８）に記載のプリプレグ。
（Ｄ）成分：熱可塑性樹脂
（１０） 前記強化繊維が炭素繊維である、上記（７）から（９）のいずれかに記載のプリプレグ。 As a result of intensive studies aimed at solving the above problems, the present inventors have found that the above problems can be overcome by combining a specific epoxy resin, an imidazole compound and a thermal facial resin, and have completed the present invention. . That is, the gist of the present invention resides in the following (1) to (10).
(1) An epoxy resin composition comprising the following components (A), (B) and (C).
(A) component: glycidylamine type epoxy resin having at least three glycidyl groups in one molecule (B) component: epoxy resin having an oxazolidone ring in the molecule (C) component: imidazole compound represented by formula (1)

... formula (1)
(2) The epoxy resin composition according to (1) above, wherein the weight ratio of component (A) to component (B) is 30:70 to 40:60.
(3) The epoxy resin composition according to (1) or (2) above, further comprising the following component (D).
(D) component: thermoplastic resin (4) Any of the above (1) to (3), wherein the glass transition temperature in the dynamic viscoelasticity test of the cured product obtained by heating at 150 ° C. for 30 minutes is 180 ° C. or higher. 1. The epoxy resin composition according to claim 1.
(5) The cured product obtained by heating at 150°C for 30 minutes has a storage elastic modulus of 2,900 MPa or more at 35°C in a dynamic viscoelasticity test, and a storage elastic modulus of 2,000 MPa or more at 150°C. The epoxy resin composition according to any one of (1) to (4) above.
(6) The epoxy resin according to any one of (1) to (5) above, wherein the cured product obtained by heating at 150° C. for 30 minutes has a reaction exothermic peak half width of 12° C. or less in differential scanning calorimetry. Composition.
(7) A prepreg containing reinforcing fibers and a matrix resin, wherein the matrix resin is an epoxy resin composition containing the following components (A), (B) and (C).
(A) component: glycidylamine type epoxy resin having at least three glycidyl groups in one molecule (B) component: epoxy resin (B) having an oxazolidone ring in the molecule
(C) component: imidazole compound (C) represented by formula (1)

... formula (1)
(8) The prepreg according to (7) above, wherein the weight ratio of component (A) to component (B) is 30:70 to 40:60.
(9) The prepreg according to (7) or (8) above, wherein the matrix resin further contains the following component (D).
(D) component: thermoplastic resin (10) The prepreg according to any one of (7) to (9) above, wherein the reinforcing fibers are carbon fibers.

INDUSTRIAL APPLICABILITY According to the present invention, an epoxy resin composition which is excellent in heat resistance and elastic modulus of a cured product, elastic modulus retention in a high temperature range, and mechanical properties in spite of having low-temperature, high-speed curability, and the epoxy resin composition. It is possible to provide a prepreg for a fiber-reinforced composite material using a material.

The following term definitions apply throughout the specification and claims.
The “half width of the reaction exothermic peak of the epoxy resin composition” is the width of the peak in the X-axis direction ( unit: °C).
"Glass transition point of cured product" is obtained by cutting out a test piece having a length of 55 mm, a width of 12.7 mm, and a thickness of 2 mm from the cured resin, and using a dynamic viscoelasticity measuring device (DMA) according to ASTM D7028. , frequency: 1 Hz, heating rate: 5 ° C./min. The storage modulus (E ') in bending mode is measured, log E ' is plotted against temperature, and the flat region before the transition of log E ' is the temperature (E'onset) at the intersection of the tangent of E' with the tangent at the inflection point of the region where log E' transitions.

・・・式（１） <Epoxy resin composition>
The epoxy resin composition of the present invention is an epoxy resin composition comprising the following components (A), (B) and (C).
(A) component: glycidylamine type epoxy resin having at least three glycidyl groups in one molecule (B) component: epoxy resin having an oxazolidone ring in the molecule (C) component: imidazole compound represented by formula (1) the below described

... formula (1)

The epoxy resin composition of the present invention preferably further contains a thermoplastic resin as component (D). Moreover, other components than the (A) component, (B) component, (C) component, and (D) component may be included as necessary within a range that does not impair the effects of the present invention. Other components include epoxy resins other than components (A) and (B), optional additives that impart specific functions, and the like.

<(A) Component>
Component (A) is a glycidylamine type epoxy resin having at least three glycidyl groups in one molecule, and is a component that imparts necessary heat resistance to the cured product of the epoxy resin composition.

Examples of component (A) include tetraglycidylamine type epoxy resins and triglycidylaminophenol type epoxy resins. These may be used individually by 1 type, and may use 2 or more types together.

Commercially available products of component (A) include, for example, Araldite (registered trademark) MY720, MY721, MY9663, MY9634, MY9655, MY0500, MY0510, MY0600, jER (registered trademark) 604 and jER630 manufactured by Mitsubishi Chemical Corporation, and Sumitomo Chemical Co., Ltd. Sumiepoxy (registered trademark) ELM-434, ELM-100 and the like manufactured by Sumitomo Chemical Co., Ltd., but are not limited to these.

<(B) component)>
Component (B) is an epoxy resin having an oxazolidone ring in the molecule, and is a component that imparts high toughness to the cured product of the epoxy resin composition.

Commercially available products of component (B) include, for example, TSR-400 manufactured by DIC.

<(C) Component>
Component (C) is 2-phenyl-4,5-dihydroxymethylimidazole represented by the following formula (1).

・・・式（１） Component (C) is a curing agent and curing catalyst for epoxy resins, and is a component that has excellent pot life at room temperature and imparts high heat resistance and high toughness to the cured epoxy resin.

... formula (1)

Commercially available products of component (C) include, for example, 2PHZ-PW manufactured by Shikoku Kasei Kogyo Co., Ltd.

<(D) Component>
(D) Component is a thermoplastic resin. Component (D) imparts high toughness to the cured product of the epoxy resin composition, suppresses the stickiness of the epoxy resin composition, adjusts the tackiness of the prepreg to an appropriate level, and prevents resin flow at high temperatures just before curing. It has the effect of suppressing

Component (D) includes, for example, polyether sulfone, polyvinyl formal, phenoxy resin, polyamide, and acrylic block copolymers. These may be used individually by 1 type, and may use 2 or more types together.

Commercially available products of component (D) include PES5003MPS manufactured by Sumitomo Chemical Co., Ltd., Ultrason E2020P-SRmicro manufactured by BASF, Virantage VW-10200 manufactured by Slovay, Vinylec E manufactured by Chisso, YP-70 and YP-50 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. 2AP0-35, TR55, TR90 from EMS Chemie; Vestosint 2158, 2159 from Evonik; M52N, M22N from Alkema;

<Other epoxy resins>
Epoxy resins (A) and (B ), an epoxy resin other than the component can be added as required.

For example, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, phenol novolac type and cresol novolak type glycidyl ether resins, naphthalene type and dicyclopentadiene type glycidyl ether resins are preferred. These may be used individually by 1 type, and may use 2 or more types together.

Other commercially available epoxy resins include JER (registered trademark) 828, 827, 807, 1001, 1002, 1004, 4004, 4007, 1032H60 manufactured by Mitsubishi Chemical Corporation, and EPICLON (registered trademark) 830, 850, N673 manufactured by DIC. , N675, N770, N775, HP4032, HP4700, HP4770, EXA-1514, Tactix® 742, 556 from Huntsman Advanced Materials, and the like.

<Other additives>
Known additives (fillers, diluents, solvents, pigments, plasticizers, antioxidants, stabilizers, etc.) can be added to the epoxy resin composition of the present invention, if necessary.

Examples of pigments include carbon black and graphene. Carbon black and graphene have the effect of coloring the epoxy resin black, hiding the color of the resin when molding the fiber-reinforced composite material described later, and imparting a high-quality appearance especially when applied to sports products. , It also has an ultraviolet absorption ability and a heat dissipation function.

<Resin composition>
The epoxy resin composition of the present invention essentially comprises (A) component, (B) component and (C) component. The ratio of the component (A) and the component (B) is preferably 30:70 to 40:60 by weight. If the content of component (A) is in this mass ratio, the heat resistance of the cured product of the epoxy resin composition increases. Further, when the content of the component (B) is in the above mass ratio, the elongation at break of the cured product of the epoxy resin composition is sufficient. The content of component (C) is based on 100% by mass of the total mass of all epoxy resins contained in the epoxy resin composition (that is, the sum of components (A), (B), and other epoxy resins). Therefore, it is preferably added in an amount of 2% by mass or more, more preferably 3% by mass or more. If the content of component (C) is 2% by mass or more, sufficient heat resistance can be imparted to the cured product of the epoxy resin composition. The content of component (D) is 2 per 100% by mass of all epoxy resins contained in the epoxy resin composition (that is, the total of component (A), component (B), and other epoxy resins). ~30% by mass is preferable, and 3 to 20% by mass is more preferable. If the content of component (D) is 2% by mass or more, sufficient toughness can be imparted to the epoxy resin. If it is 30% by mass or less, the reinforcing fibers can be sufficiently impregnated with the epoxy resin composition for use as a prepreg for fiber-reinforced composite materials, and the prepreg for fiber-reinforced composite materials has an appropriate surface tack. be able to.

<Half width of reaction exotherm>
The half-value width of reaction heat (Heat Flow) in differential scanning calorimetry (DSC) of the epoxy resin composition is preferably 12° C. or less, more preferably 10° C. or less. If the half-value width of the reaction heat generation is 10° C. or less, the epoxy resin composition is excellent in rapid curability and in imparting heat resistance to the cured product.

<Glass transition point of cured product>
A cured product obtained by heating the epoxy resin composition at 150° C. for 30 minutes preferably has a glass transition point of 180° C. or higher as determined by dynamic viscoelasticity measurement. If the cured product has a glass transition point of 180° C. or higher, it has sufficient heat resistance for use in aircraft, automobiles, and bicycles.

<Effect>
Since the epoxy resin composition of the present invention described above contains the components (A), (B), (C), and (D) described above, it has low-temperature and high-speed curability. Specifically, the epoxy resin composition is sufficiently cured by heating at 150° C. within 30 minutes.
In addition, the epoxy resin composition of the present invention is excellent in heat resistance of the cured product, retention of elastic modulus in a high temperature range, and mechanical properties. Regarding heat resistance, specifically, the cured product has a glass transition point of 180° C. or higher when cured at 150° C. for 30 minutes. Specifically, the storage elastic modulus of a cured product obtained by curing at 150°C for 30 minutes is 2,000 MPa or more at 150°C. As for mechanical properties, the cured product obtained by curing at 150° C. for 30 minutes has an elongation at break of 5% or more in a three-point bending test.

・・・式（１）
（Ｄ）成分：熱可塑性樹脂 <Prepreg>
The prepreg of the present invention is a prepreg containing reinforcing fibers and a matrix resin, and the matrix resin is an epoxy resin composition containing the following components (A), (B), (C) and (D). An epoxy containing 30 parts by mass or more and 60 parts by mass or less of the component (A) and 25 parts by mass or more and 55 parts by mass or less of the component (B) in 100 parts by mass of the total epoxy resin contained in the epoxy resin composition It is a prepreg that is a resin composition.
(A) component: glycidylamine type epoxy resin having at least three glycidyl groups in one molecule (B) component: epoxy resin (B) having an oxazolidone ring in the molecule
(C) component: imidazole compound (C) represented by formula (1)

... formula (1)
(D) component: thermoplastic resin

<Reinforcing fiber>
Examples of reinforcing fibers include carbon fibers, aramid fibers, nylon fibers, high-strength polyester fibers, glass fibers, boron fibers, alumina fibers, and silicon nitride fibers. Among these, carbon fiber, aramid fiber, glass fiber, boron fiber, alumina fiber, and silicon nitride fiber are preferred from the viewpoint of excellent flame retardancy, and carbon fiber is particularly preferred from the viewpoint of excellent specific strength and specific elasticity. Forms of reinforcing fibers include unidirectionally aligned fibers, woven fabrics, non-crimped fabrics, non-woven fabrics, and the like.

The content of the epoxy resin composition in the prepreg for fiber-reinforced composite material of the present invention is preferably 15 to 65% by mass, more preferably 20 to 60% by mass.
The prepreg for fiber-reinforced composite material of the present invention can be produced by a known method using the epoxy resin composition of the present invention and reinforcing fibers.

Since the prepreg for a fiber-reinforced composite material of the present invention described above contains the epoxy resin composition of the present invention, it can be cured at a low temperature (150° C.) in a short time (30 minutes). However, it has storage stability at room temperature for more than one month. Furthermore, the cured product exhibits a high glass transition point (180° C. or higher), and is excellent in heat resistance, retention of elastic modulus in a high temperature range, and mechanical properties.

<Fiber reinforced composite material>
The fiber-reinforced composite material in the present invention can be produced by a known method using the prepreg of the present invention. For example, there is a method in which a prepreg is sandwiched between a lower mold and an upper mold having a predetermined surface shape, and pressurized and heated to obtain a cured product having a desired shape. Since the fiber-reinforced composite material of the present invention is obtained by curing the prepreg of the present invention, it is excellent in heat resistance, retention of elastic modulus in a high temperature range, and mechanical properties.

EXAMPLES The present invention will be specifically described below with reference to Examples, but the present invention is not limited to these.

<Each component>
(A) Component As the (A) component, the compounds shown below were used.
· A-1: Triglycidyl-p-aminophenol (MY0510 manufactured by Huntsman Advanced Materials).
· A-2: Tetraglycidyldiaminodiphenylmethane (manufactured by Mitsubishi Chemical Corporation: jER604).

(B) Component As the component (B), the compounds shown below were used.
・ Oxazolidone ring-modified epoxy resin (DIC TSR-400)

(C) Component As the (C) component, the compounds shown below were used.
· C-1: 2-phenyl-4,5-dihydroxymethylimidazole (2PHZ-PW manufactured by Shikoku Kasei Co., Ltd.).
· C-2: 2-phenyl-4-methyl-5-hydroxymethylimidazole (2P4MHZ-PW manufactured by Shikoku Kasei Co., Ltd.).
· C-3: 1-(4,6-diamino-s-triazin-2-yl)ethyl-2-methylimidazole (2MZA-PW manufactured by Shikoku Chemical Industry Co., Ltd.).

(D) Component As the (D) component, the compounds shown below were used.
· D-1: Polyethersulfone (Sumika Excel PES5003MPS manufactured by Sumitomo Chemical Co., Ltd.).
· D-2: Polyvinyl formal (Vinylec E manufactured by Chisso Corporation).

(other ingredients )
As other epoxy resins, the following compounds were used.
・Liquid bisphenol A type epoxy resin (Mitsubishi Chemical Corporation jER828)
・ Solid bisphenol A type epoxy resin (jER1002 manufactured by Mitsubishi Chemical Corporation)
・ Solid bisphenol F type epoxy resin (JER4004 manufactured by Mitsubishi Chemical Corporation)
・Solid cresol novolac type epoxy resin (EPICLON N673 manufactured by DIC)
- Solid phenolic novolac type epoxy resin (EPICLON N775 manufactured by DIC)
- Solid polyfunctional naphthalene type epoxy resin (EPICLON HP4770 manufactured by DIC)
・Solid bisphenol S-type epoxy resin (EXA1514 manufactured by DIC)
・ Curing agent for epoxy resin (Dicy15)

<Measurement/Evaluation>
(Production of resin plate)
The epoxy resin composition was injected between two release-treated 4 mm thick glass plates via a 2 mm thick polytetrafluoroethylene (PTFE) spacer and heated at 150° C. for 30 minutes to form a cured resin plate. Obtained. This was used as a resin base plate for measuring three-point bending physical properties and glass transition point.

(Measurement of reaction calorific value)
1 to 10 mg of the epoxy resin composition before curing is sampled (measurement is possible if the amount within this range is sampled), and a differential scanning calorimeter (DSC-Q100, manufactured by TA Instruments) is used to The temperature was raised to 300°C at a temperature elevation rate of 10°C/min, and the reaction calorific value, reaction initiation temperature, and reaction peak temperature were measured.

(Measurement of half width of reaction exothermic peak)
In the measurement of the exothermic value of the reaction, the width (° C.) of the peak in the X-axis direction at half the height of the exothermic peak was determined as the half width (° C.) of the exothermic peak.

(Evaluation of bending properties)
A test piece having a length of 60 mm, a width of 8 mm, and a thickness of 2 mm was cut out from the cured resin plate. Using an Instron universal testing machine equipped with a three-point bending jig (both indenter and support: 3.2 mmR, distance between supports = 16 times the thickness of the test piece), crosshead speed: 2 mm / min. Point bending physical properties (bending strength, bending elastic modulus, bending elongation at maximum load, bending elongation at break) were measured.

(Measurement of glass transition point)
A test piece having a length of 55 mm, a width of 12.7 mm, and a thickness of 2 mm was cut out from the cured resin plate. Using a dynamic viscoelasticity measuring device (manufactured by TA Instruments, "DMA-Q800"), according to ASTM D7028, frequency: 1 Hz, heating rate: 5 ° C./min. Storage modulus E' was measured. Plotting logE' against temperature, the temperature at the intersection of the tangent to the flat region before the transition of logE' and the tangent to the inflection point of the region to which logE' transitions was taken as the glass transition point (E'onset). . In Tables 1 and 2, "E'at 35C" means storage modulus E' at 35°C, and "E'at 150C" means storage modulus E' at 150°C. , "E'at 170C" is the storage modulus E' at 170°C.

<Example 1>
Components (A) and (D) were weighed into a glass flask according to the composition shown in Table 1, melted and mixed at 140°C to prepare a masterbatch.
The amount of component (B) shown in Table 1 was weighed and added to the obtained masterbatch, and the mixture was stirred and mixed at 140°C. This was slowly cooled to 65° C., and the amount of component (C) and remaining components shown in Table 1 were added and mixed with stirring until uniform. After that, vacuum defoaming was performed to obtain an epoxy resin composition.
Various measurements and evaluations were performed using the obtained epoxy resin composition. Table 1 shows the results.

<Examples 2 to 4, reference examples >
An epoxy resin composition was prepared in the same manner as in Example 1 except that the amount of each component was changed to the amount shown in Examples 2 to 4 and Reference Example in Table 1, and each measurement and evaluation were performed. Table 1 shows the results. In Table 1, Example 5 is read as Reference Example.

<Comparative Examples 1 to 14>
An epoxy resin composition was prepared in the same manner as in Example 1 except that the amount of each component was changed to the amount shown in Table 2, and each measurement and evaluation were performed. Table 2 shows the results.

As is clear from the results in Table 1, although the epoxy resin compositions obtained in each example have low-temperature and high-speed curability, the cured products have heat resistance, elastic modulus, and elastic modulus in the high-temperature region. was excellent in retention and mechanical properties.

On the other hand, as is clear from the results in Table 2, the epoxy resin composition of Comparative Example 1, in which the content of component (A) was less than 30%, had a glass transition point of less than 180°C.
The epoxy resin compositions of Comparative Examples 2 to 9, in which other epoxy resins were used instead of the component (B), had a glass transition point, an elastic modulus at 150°C, an elongation at flexural break, or storage stability. A poor result was obtained.
In Comparative Example 10, in which 2-phenyl-4-methyl-5-hydroxymethylimidazole was used as the component (C), the half width of the reaction exotherm in differential scanning calorimetry was 12° C. or more.
Comparative Example 11, in which the amount of 2-phenyl-4,5-dihydroxymethylimidazole as component (C) is small, not only has a glass transition point of less than 180°C, but also has a half-value width of 12°C for the reaction exotherm in differential scanning calorimetry. °C or higher.
Comparative Example 12, in which 2MZA-PW was used instead of 2-phenyl-4,5-dihydroxymethylimidazole as component (C), resulted in inferior glass transition point and storage stability.
Comparative Example 13, in which polyvinyl formal was used as the component (D), resulted in poor retention of elastic modulus at high temperatures.
Comparative Example 14, in which a difunctional glycidyl ether type epoxy is used in place of the glycidyl amine type epoxy resin having tri- or more functional glycidyl groups as the component (A), results in an inferior glass transition point.

The fiber-reinforced composite material obtained using the epoxy resin composition of the present invention is suitably used for aircraft members, automobile members, bicycle members, sporting goods members, railway vehicle members, ship members, construction members, oil risers, etc. It is particularly suitable for aircraft members, automobile members, and bicycle members that require high heat resistance and mechanical properties.

Claims (6)

A prepreg containing carbon fibers and a matrix resin, wherein the matrix resin is an epoxy resin composition containing the following components (A), (B) and (C), and the epoxy
30 parts by mass or more of the component (A) in 100 parts by mass of the total epoxy resin contained in the resin composition
60 parts by mass or less of all epoxy resins contained in the epoxy resin composition containing 25 parts by mass or more and 55 parts by mass or less of the component (B) in 100 parts by mass of all epoxy resins contained in the epoxy resin composition In a dynamic viscoelasticity test of a cured product obtained by heating the epoxy resin composition at 150°C for 30 minutes containing 3% by mass or more of the component (C) with respect to 100% by mass of the total mass, A prepreg having a storage modulus of 2,000 MPa or more.
(A) component: tetraglycidylamine type epoxy resin and triglycidylaminophenol type epoxy resin (B) component: epoxy resin having an oxazolidone ring in the molecule (C) component: imidazole compound represented by formula (1)

The prepreg according to claim 1, wherein the ratio of said component (A) and said component (B) is 30:70 to 40:60 in mass ratio. The prepreg according to claim 1 or 2, wherein the matrix resin further contains the following component (D).
(D) Component: Polyethersulfone The prepreg according to any one of claims 1 to 3, wherein a cured product obtained by heating the epoxy resin composition at 150°C for 30 minutes has a glass transition temperature of 180°C or higher in a dynamic viscoelasticity test. 5. Any one of claims 1 to 4 , wherein the cured product obtained by heating the epoxy resin composition at 150° C. for 30 minutes has a reaction exothermic peak half width of 12° C. or less in differential scanning calorimetry.
The prepreg described in the paragraph. The epoxy resin composition contains 3 to 20% by mass of the component (D) polyethersulfone with respect to 100% by mass of the total mass of all epoxy resins contained in the epoxy resin composition, and the epoxy resin composition contains A liquid bisphenol A type epoxy resin is blended, and 30 parts by mass or more and 60 parts by mass or less of the component (A) is contained in 100 parts by mass of the total epoxy resin contained in the epoxy resin composition, and the component (A) is triglycidyl. -p-aminophenol and tetraglycidyldiaminodiphenylmethane.