阅读说明：本技术 热固性树脂组合物、预浸料及纤维增强复合材料 (Thermosetting resin composition, prepreg, and fiber-reinforced composite material ) 是由 三角润 町田银平 坂田宏明 于 2019-02-06 设计创作，主要内容包括：本发明提供热固性树脂组合物、使用了该热固性树脂组合物的预浸料、纤维增强复合材料,所述热固性树脂组合物至少包含[A]具有2个以上缩水甘油基的环氧树脂、[B]具有2个以上氰酸酯基的氰酸酯树脂、[C]胺化合物,且满足以下条件(1)和(2)。(1)0.25≤热固性树脂组合物中的缩水甘油基的摩尔数/热固性树脂组合物中的氰酸酯基的摩尔数≤1.5(2)0.05≤热固性树脂组合物中的氨基所包含的活性氢的摩尔数/热固性树脂组合物中的氰酸酯基的摩尔数≤0.5。本发明提供吸湿后的高温环境下的力学特性和耐热性优异,具有能够在短时间固化的优异的反应性的热固性树脂组合物、热固性树脂组合物含浸于增强纤维而成的室温下的操作性(粘合性)优异的预浸料、以及包含热固性树脂组合物和增强纤维的纤维增强复合材料。(The present invention provides a thermosetting resin composition which contains at least [ A ] an epoxy resin having 2 or more glycidyl groups, [ B ] a cyanate ester resin having 2 or more cyanate groups, and [ C ] an amine compound, and satisfies the following conditions (1) and (2), and a prepreg and a fiber-reinforced composite material using the thermosetting resin composition. (1) 0.25. ltoreq. glycidyl groups/isocyanate groups/thermosetting resin composition mol 1.5(2) 0.05. ltoreq. active hydrogen contained in amino groups/thermosetting resin composition mol 0.5. The invention provides a thermosetting resin composition which is excellent in mechanical properties and heat resistance in a high-temperature environment after moisture absorption and has excellent reactivity and can be cured in a short time, a prepreg which is formed by impregnating reinforcing fibers with the thermosetting resin composition and is excellent in operability (adhesiveness) at room temperature, and a fiber-reinforced composite material comprising the thermosetting resin composition and the reinforcing fibers.)

1. A thermosetting resin composition which comprises at least the following constituent elements [ A ] to [ C ] and satisfies the following conditions (1) and (2),

[A] an epoxy resin having 2 or more glycidyl groups,

[B] a cyanate ester resin having 2 or more cyanate groups,

[C] an amine compound which is a compound having a structure represented by,

(1) 0.25. ltoreq. of glycidyl groups/1.5 mol of cyanate groups in the thermosetting resin composition,

(2)0.05 or less and the number of moles of active hydrogen contained in the amino group in the thermosetting resin composition/the number of moles of cyanate group in the thermosetting resin composition is 0.5 or less.

2. The thermosetting resin composition according to claim 1, wherein the amine compound as the constituent [ C ] is an aromatic amine compound having two or more amino groups.

3. The thermosetting resin composition according to claim 1 or 2, wherein the amine compound as the constituent [ C ] is a solid at 25 ℃.

4. The thermosetting resin composition according to claim 2 or 3, wherein the amine compound as the constituent [ C ] comprises diaminodiphenyl sulfone or diaminodiphenyl ketone.

5. The thermosetting resin composition according to any one of claims 1 to 4, wherein the epoxy resin having 2 or more glycidyl groups as the constituent [ A ] contains 40 to 100 parts by mass of a 3-or more-functional glycidyl amine type epoxy resin per 100 parts by mass of the total epoxy resin.

6. The thermosetting resin composition according to any one of claims 1 to 5, wherein the cyanate ester resin having 2 or more cyanate groups as the constituent [ B ] comprises 20 to 100 parts by mass of the cyanate ester resin represented by the formula (1) per 100 parts by mass of the entire cyanate ester resins,

in the formula (1), R₁～R₄At least one selected from the group consisting of a hydrogen atom, an aliphatic hydrocarbon group having 1 to 4 carbon atoms, an alicyclic hydrocarbon group having 4 or less carbon atoms, and a halogen atom, and n represents 2 to 20.

7. The thermosetting resin composition according to any one of claims 1 to 6, further comprising a thermoplastic resin.

8. The thermosetting resin composition according to any one of claims 1 to 7, wherein an exothermic peak of 100mW/g or more is present at 160 ℃ to 200 ℃ in an exothermic curve obtained by differential scanning calorimetry at a temperature rise rate of 5 ℃/min.

9. The thermosetting resin composition according to any one of claims 1 to 8, having a storage elastic modulus at 30 ℃ of 0.1 to 100,000Pa as measured by a dynamic viscoelasticity test at a frequency of 0.5 Hz.

10. A prepreg obtained by impregnating reinforcing fibers with the thermosetting resin composition according to any one of claims 1 to 9.

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

12. A fiber-reinforced composite material comprising a reinforcing fiber and a cured resin obtained by curing the thermosetting resin composition according to any one of claims 1 to 9.

Technical Field

The present invention relates to a thermosetting resin composition having excellent mechanical properties and heat resistance in a high-temperature environment after moisture absorption and excellent reactivity which enables curing in a short time, a prepreg obtained by impregnating a reinforcing fiber with the thermosetting resin composition and having excellent handleability (adhesiveness) at room temperature, and a fiber-reinforced composite material comprising the thermosetting resin composition and the reinforcing fiber.

Background

Conventionally, fiber-reinforced composite materials made of reinforcing fibers such as carbon fibers and glass fibers and thermosetting resins such as epoxy resins, phenol resins and cyanate ester resins are used in various fields such as aviation, aerospace, automobiles, railway vehicles, ships, civil engineering and construction, and sporting goods because they are lightweight, and have excellent mechanical properties such as strength and rigidity, heat resistance, and corrosion resistance. In particular, in applications requiring high performance, a fiber-reinforced composite material using continuous reinforcing fibers is used, and carbon fibers having excellent specific strength and specific elastic modulus are used as the reinforcing fibers. In recent years, as the number of use cases of fiber-reinforced composite materials increases, the requirements become more stringent. In particular, when applied to structural materials for aerospace use, the surface becomes high temperature due to friction with air, and moisture in the moisture cloud is further absorbed, and therefore sufficient physical properties are required to be expressed even in a high-temperature environment after moisture absorption.

General epoxy resin composite materials tend to have a property of easily absorbing moisture, and mechanical properties and heat resistance in a high-temperature environment after moisture absorption tend to be insufficient. Further, a general cyanate ester resin-based composite material is not likely to absorb moisture, and has excellent mechanical properties even in a high-temperature environment after moisture absorption, but has a problem that it requires a long time at a high temperature of 200 ℃ or higher at the time of molding because of its low reactivity. Further, since cyanate ester resins generally have high crystallinity and are solid at around room temperature, they have a problem that they have low adhesiveness when impregnated with reinforcing fibers to form prepregs, and thus have poor handleability as prepregs. Therefore, development of a thermosetting resin composition which is excellent in mechanical properties and heat resistance in a high-temperature environment after moisture absorption, has excellent reactivity capable of being cured at a low temperature or in a short time, and is further excellent in handling properties (adhesiveness) as a prepreg has been desired.

Disclosure of Invention

Problems to be solved by the invention

However, the thermosetting resin compositions disclosed in patent documents 1 and 2 have poor reactivity between the epoxy resin and the cyanate ester compound, and the effect of shortening the curing time is insufficient. In the mixture of the amine compound and the cyanate ester resin described in patent document 3, since a large number of triazine ring structures formed by the reaction of the cyanate ester resin alone exist, the mechanical properties under a high-temperature environment after moisture absorption are excellent, but the glass transition temperature after moisture absorption is insufficient. The thermosetting resin composition described in patent document 4 has a problem that the viscosity at a high temperature exceeding 80 ℃ is remarkably increased due to high reactivity, and the workability and physical properties of a cured product are lowered in a resin kneading step, an intermediate substrate manufacturing step such as a prepreg, and the like. Further, the mechanical properties and heat resistance of the resulting cured product under a high-temperature environment after moisture absorption are insufficient.

Accordingly, an object of the present invention is to provide a thermosetting resin composition which is excellent in mechanical properties and heat resistance in a high-temperature environment after moisture absorption and has excellent reactivity capable of being cured in a short time, and a prepreg and a fiber-reinforced composite material which are excellent in adhesion at room temperature.

Means for solving the problems

In order to solve such problems, the thermosetting resin composition of the present invention has the following configuration. That is to say that the first and second electrodes,

a thermosetting resin composition which comprises at least the following constituent elements [ A ] to [ C ] and satisfies the following conditions (1) and (2).

[A] Epoxy resin having 2 or more glycidyl groups

[B] Cyanate ester resin having 2 or more cyanate groups

[C] Amine compound

(1)0.25 or less moles of glycidyl groups in the thermosetting resin composition/moles of cyanate groups in the thermosetting resin composition 1.5 or less

(2)0.05 or less and the number of moles of active hydrogen contained in the amino group in the thermosetting resin composition/the number of moles of cyanate group in the thermosetting resin composition is 0.5 or less.

The prepreg of the present invention has the following configuration. That is to say that the first and second electrodes,

a prepreg obtained by impregnating reinforcing fibers with the thermosetting resin composition.

Further, the fiber-reinforced composite material of the present invention has any one of the following configurations. That is to say that the first and second electrodes,

a fiber-reinforced composite material obtained by curing the prepreg,

alternatively, the first and second electrodes may be,

a fiber-reinforced composite material comprising a reinforcing fiber and a cured resin product obtained by curing the thermosetting resin composition.

The thermosetting resin composition of the present invention is preferably an aromatic amine compound having two or more amino groups as the amine compound of the constituent [ C ].

The thermosetting resin composition of the present invention is preferably such that the amine compound as the constituent [ C ] is solid at 25 ℃.

The thermosetting resin composition of the present invention preferably contains diaminodiphenyl sulfone or diaminodiphenyl ketone as the amine compound of the constituent [ C ].

The thermosetting resin composition of the present invention preferably contains 40 to 100 parts by mass of a 3-or more-functional glycidylamine-type epoxy resin per 100 parts by mass of the total epoxy resin as the epoxy resin having 2 or more glycidyl groups constituting the constituent [ a ].

The thermosetting resin composition of the present invention preferably contains, as the constituent [ B ], a cyanate ester resin having 2 or more cyanate groups, and 20 to 100 parts by mass of a cyanate ester resin represented by formula (1) per 100 parts by mass of the entire cyanate ester resin.

(in the formula (1), R₁～R₄At least one selected from the group consisting of a hydrogen atom, an aliphatic hydrocarbon group having 1 to 4 carbon atoms, an alicyclic hydrocarbon group having 4 or less carbon atoms, and a halogen atom, and n represents 2 to 20. )

The thermosetting resin composition of the present invention preferably further comprises a thermoplastic resin.

The thermosetting resin composition of the present invention preferably has an exothermic peak of 100mW/g or more in an exothermic curve obtained by differential scanning calorimetry at a temperature rise rate of 5 ℃/min of 160 to 200 ℃.

The thermosetting resin composition of the present invention preferably has a storage elastic modulus at 30 ℃ of 0.1 to 100,000Pa as measured by a dynamic viscoelasticity test at a frequency of 0.5 Hz.

ADVANTAGEOUS EFFECTS OF INVENTION

In the present invention, by containing an epoxy resin, a cyanate ester resin, and an amine compound, a cured thermosetting resin excellent in mechanical properties and heat resistance can be obtained. While a cured epoxy resin formed by a reaction between a general epoxy resin and an amine compound tends to have high hygroscopicity, the cured thermosetting resin of the present invention has low hygroscopicity and exhibits excellent mechanical properties and heat resistance even in a high-temperature environment after moisture absorption.

Further, the reaction of the epoxy resin and the cyanate ester resin is promoted by heat generation due to the nucleophilic reaction of the amine compound with the cyanate ester resin, and the effect that the entire reaction is completed in a short time can be obtained. In addition, since the crystallinity of the cyanate ester resin is reduced and the prepreg obtained by impregnating the reinforcing fiber with the thermosetting resin composition of the present invention exhibits good adhesiveness even at room temperature by blending the epoxy resin and the amine compound with the cyanate ester resin, the prepreg exhibits good adhesiveness.

The fiber-reinforced composite material obtained by curing the thermosetting resin composition and the prepreg of the present invention can be molded in a shorter time than a conventional fiber-reinforced composite material using a cyanate ester resin as a matrix resin, which does not contain an epoxy resin and an amine compound, and therefore, the molding time and the molding cost of an application product for computer applications such as aircraft structural members, wings of windmills, automobile outer panels, IC trays, and housings of notebook personal computers can be significantly reduced.

Detailed Description

The thermosetting resin composition of the present invention has the following constitution.

A thermosetting resin composition which comprises at least the following constituent elements [ A ] to [ C ] and satisfies the following conditions (1) and (2).

[A] Epoxy resin having 2 or more glycidyl groups

[B] Cyanate ester resin having 2 or more cyanate groups

[C] Amine compound

(1)0.25 or less of the number of moles of epoxy groups in the thermosetting resin composition/1.5 or less of the number of moles of cyanate groups in the thermosetting resin composition

(2)0.05 or less and the number of moles of active hydrogen contained in the amino group in the thermosetting resin composition/the number of moles of cyanate group in the thermosetting resin composition is 0.5 or less.

The constituent [ a ] used in the present invention is an epoxy resin having 2 or more glycidyl groups. If the number of glycidyl groups is less than 2, the glass transition temperature of a cured thermosetting resin obtained by heat curing cannot be sufficiently high. Examples of the epoxy resin usable in the present invention include bisphenol type epoxy resins such as bisphenol a type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, bisphenol S type epoxy resin and the like, brominated epoxy resins such as tetrabromobisphenol a diglycidyl ether and the like, epoxy resins having a biphenyl skeleton, epoxy resins having a naphthalene skeleton, epoxy resins having a dicyclopentadiene skeleton, novolac type epoxy resins such as phenol novolac type epoxy resin, cresol novolac type epoxy resin and the like, N, O-triglycidyl-m-aminophenol, N, O-triglycidyl-p-aminophenol, N, O-triglycidyl-4-amino-3-methylphenol, N' -tetraglycidyl-4, glycidyl amine type epoxy resins such as 4 ' -methylenedianiline, N ' -tetraglycidyl-2, 2 ' -diethyl-4, 4 ' -methylenedianiline, N ' -tetraglycidyl-m-xylylenediamine, N-diglycidylaniline, N-diglycidylaniline, and the like, resorcinol diglycidyl ether, triglycidyl isocyanurate, and the like. The thermosetting resin composition of the present invention is more preferably a composition in which a glycidyl amine type epoxy resin containing 3 or more glycidyl groups is contained in an amount of 40 to 100 parts by mass based on 100 parts by mass of the total epoxy resins, and thus a cured product having a high glass transition temperature and a high elastic modulus can be obtained. Examples of the glycidyl amine type epoxy resin containing 3 or more glycidyl groups include N, O-triglycidyl-m-aminophenol, N, O-triglycidyl-p-aminophenol, N, O-triglycidyl-4-amino-3-methylphenol, N '-tetraglycidyl-4, 4' -methylenedianiline, N '-tetraglycidyl-2, 2' -diethyl-4, 4 '-methylenedianiline, and N, N' -tetraglycidyl-m-xylylenediamine.

These epoxy resins may be used alone or in combination of two or more. The use of an epoxy resin that exhibits fluidity at any temperature in combination with an epoxy resin that does not exhibit fluidity at any temperature is effective for controlling the fluidity of the matrix resin when the resulting prepreg is thermally cured. For example, if the fluidity exhibited until the matrix resin gels during thermosetting is small, the orientation of the reinforcing fibers is not likely to be disturbed, and the matrix resin is not likely to flow out of the system, so that the fiber mass content is likely to be controlled within a predetermined range, and as a result, favorable mechanical properties as a fiber-reinforced composite material tend to be exhibited. In addition, it is also effective to combine a plurality of epoxy resins exhibiting various viscoelastic behaviors at arbitrary temperatures to make the adhesiveness and drapability of the resulting prepreg appropriate.

The thermosetting resin composition of the present invention may contain an epoxy resin other than the constituent [ a ], for example, a monoepoxy resin having only 1 glycidyl group in 1 molecule, an alicyclic epoxy resin, or the like, as long as the heat resistance and mechanical properties are not significantly deteriorated.

The constituent [ B ] included in the present invention is a cyanate ester resin having 2 or more cyanate groups. When the number of cyanate groups is less than 2, the glass transition temperature of a cured thermosetting resin obtained by heat curing cannot be sufficiently high. Examples of the cyanate ester resin usable in the present invention include bisphenol a type cyanate ester resin, bisphenol E type cyanate ester resin, bisphenol F type cyanate ester resin, cyanate ester resin having a biphenyl skeleton, cyanate ester resin having a naphthalene skeleton, cyanate ester resin having a dicyclopentadiene skeleton, phenol novolac type cyanate ester resin, cresol novolac type cyanate ester resin, phenol phenyl aralkyl type cyanate ester resin, phenol biphenyl aralkyl type cyanate ester resin, naphthol phenyl aralkyl type cyanate ester resin, and the like. The thermosetting resin composition of the present invention preferably contains 20 to 100 parts by mass of the cyanate ester resin represented by formula (1) per 100 parts by mass of the total cyanate ester resin, because a cured product having a high glass transition temperature after moisture absorption can be obtained. These cyanate ester resins may be used alone or in combination of two or more.

(in the formula (1), R₁～R₄At least one selected from the group consisting of a hydrogen atom, an aliphatic hydrocarbon group having 1 to 4 carbon atoms, an alicyclic hydrocarbon group having 4 or less carbon atoms, and a halogen atom, and n represents 2 to 20. )

The constituent [ C ] in the present invention is an amine compound. An amine compound which is solid at 25 ℃ is preferable because it has a good pot life in a resin kneading step, a prepreg manufacturing step, and the like. Further, if the aromatic amine compound has 2 or more amino groups, a crosslinked structure can be formed, and the resulting chemical structure is rigid, and therefore, a cured thermosetting resin having a high glass transition temperature can be obtained, which is preferable. Examples of the constituent [ C ] include 3,3 '-diisopropyl-4, 4' -diaminodiphenylmethane, 3,3 '-di-tert-butyl-4, 4' -diaminodiphenylmethane, 3,3 ', 5, 5' -tetraethyl-4, 4 '-diaminodiphenylmethane, 3, 3' -diaminodiphenylmethane, 4 '-diaminodiphenylmethane, 3, 3' -diisopropyl-4, 4 '-diaminodiphenylketone, 3, 3' -di-tert-butyl-4, 4 '-diaminodiphenylketone, 3, 3', 5,5 '-tetraethyl-4, 4' -diaminodiphenylketone, 3,3 '-diaminodiphenylketone, 4' -diaminodiphenylketone, and the like, 3,3 '-diisopropyl-4, 4' -diaminodiphenyl sulfone, 3 '-di-tert-butyl-4, 4' -diaminodiphenyl sulfone, 3 ', 5, 5' -tetraethyl-4, 4 '-diaminodiphenyl sulfone, 3' -diaminodiphenyl sulfone, m-phenylenediamine, m-xylylenediamine, diethyltoluenediamine, and the like.

Among them, diaminodiphenyl sulfone and diaminodiphenyl ketone have electron-withdrawing functional groups, and therefore, the nucleophilicity of the amine is appropriately suppressed, and a good pot life can be obtained in a resin kneading step, a step of producing an intermediate substrate such as a prepreg, and the like. Furthermore, diaminodiphenyl sulfone and diaminodiphenyl ketone have a rigid chemical structure, and therefore a cured thermosetting resin having high heat resistance can be obtained, which is preferable. These amine compounds may be used alone or in combination of two or more. When mixed with other components, the mixture may be in any form of powder or liquid, or the powder may be mixed with a liquid amine compound.

The thermosetting resin composition of the present invention satisfies both the following (1) and (2).

(1)0.25 or less moles of glycidyl groups in the thermosetting resin composition/moles of cyanate groups in the thermosetting resin composition 1.5 or less

(2)0.05 or less and the number of moles of active hydrogen contained in the amino group in the thermosetting resin composition/the number of moles of cyanate group in the thermosetting resin composition is 0.5 or less.

Formed by reaction of cyanate groups with glycidyl groups in the epoxy resinThe oxazolidone ring exhibits excellent mechanical properties and heat resistance in a high-temperature environment after moisture absorption. Further, the reaction of the epoxy resin and the cyanate ester resin is promoted by heat generation due to the nucleophilic reaction of the amine compound with the cyanate ester resin, and the effect that the entire reaction is completed in a short time can be obtained. Further, the reaction of the amine compound with the cyanate ester resin can form an isourea structure, and the mechanical properties at room temperature are improved by the hydrogen bonding property of the isourea structure. On the other hand, the amount of moisture absorption tends to increase due to the hydrogen bonding property of the isourea structure. In (1), if the ratio is less than 0.25, the adhesiveness as a prepreg becomes insufficient. On the other hand, if the ratio exceeds 1.5, the mechanical properties in a high-temperature environment after moisture absorptionThe properties and heat resistance become insufficient.

In (2), if the ratio is less than 0.05 or more, the effect of improving the reactivity of the thermosetting resin composition is not obtained, and if it exceeds 0.5, the increase in viscosity at a high temperature exceeding 80 ℃ cannot be suppressed, and the mechanical properties and heat resistance in a high-temperature environment after moisture absorption become insufficient.

Here, the number of moles of glycidyl groups in the epoxy resin as the constituent [ a ] is calculated as follows.

The number of moles of glycidyl groups contained in the epoxy resin as the constituent [ a ] is equal to the mass part of the epoxy resin as the constituent [ a ] per the epoxy equivalent of the epoxy resin as the constituent [ a ].

When the epoxy resin as the constituent [ a ] contains 2 or more epoxy resins, the sum of the number of moles of epoxy groups in each component is calculated as follows, for example, when 2 components of the components 1 and 2 are contained.

The number of moles of glycidyl groups contained in the epoxy resin as the constituent [ a ] is equal to the mass part of the epoxy resin of the component 1/the epoxy equivalent of the epoxy resin of the component 1 + the mass part of the epoxy resin of the component 2/the epoxy equivalent of the epoxy resin of the component 2.

The molar number of cyanate groups in the cyanate ester resin as the constituent [ B ] is calculated as follows.

The molar number of cyanate groups of the cyanate ester resin as the constituent [ B ] is equal to the mass part of the cyanate ester resin as the constituent [ B ]/the cyanate ester equivalent of the cyanate ester resin as the constituent [ B ].

The molar number of active hydrogen in the amine compound as the constituent [ C ] is calculated as follows.

The molar number of active hydrogen in the amine compound as the constituent [ C ] is equal to the mass part of the amine compound as the constituent [ C ] per equivalent of active hydrogen in the amine compound as the constituent [ C ].

The epoxy equivalent is a value determined by the method described in JIS K7236-2009. The active hydrogen equivalent is an amine value determined by the method described in JIS K7237-1995. The cyanate equivalent refers to cyanate equivalent calculated by identifying chemical structure and ratio thereof by liquid chromatography mass spectrometry (LC/MS method).

In addition to the amine compound as the constituent [ C ] in the present invention, other curing accelerators may be used in combination within a range not impairing the heat resistance and heat stability of the thermosetting resin composition. Examples of the other curing accelerators include cationic polymerization initiators, tertiary amines, imidazole compounds, urea compounds, and hydrazide compounds.

The thermosetting resin composition of the present invention preferably further contains a thermoplastic resin. The thermoplastic resin is contained for the purpose of controlling the adhesiveness of the resulting prepreg, controlling the fluidity of the matrix resin when the prepreg is cured by heating, and imparting toughness without impairing the heat resistance and elastic modulus of the resulting fiber-reinforced composite material. From the viewpoint of controlling the viscoelasticity of the thermosetting resin composition and the adhesiveness of the prepreg, the amount of the thermoplastic resin to be blended is preferably 1 to 30% by mass in the thermosetting resin composition. The thermoplastic resin is preferably a thermoplastic resin having a polyaryl ether skeleton, and examples thereof include polysulfone, polyphenylsulfone, polyethersulfone, polyetherimide, polyphenylene ether, polyetheretherketone, and polyetherethersulfone, and these thermoplastic resins having a polyaryl ether skeleton may be used alone or in combination as appropriate. Among them, polyether sulfone and polyether imide are preferably used because they can impart toughness without lowering the heat resistance and mechanical properties of the resulting fiber-reinforced composite material.

As the terminal functional group of the thermoplastic resin composed of the polyarylether skeleton, a group such as a primary amine, a secondary amine, a hydroxyl group, a carboxyl group, a thiol group, an acid anhydride, or a halogen group (chlorine or bromine) can be used. Among these, a prepreg having excellent storage stability can be obtained when the functional group is a halogen group having low reactivity with an epoxy resin, and a thermosetting resin composition having excellent adhesion with a thermoplastic resin can be obtained when the functional group is a functional group other than a halogen group because the functional group has reactivity with an epoxy resin and a cyanate resin.

The thermosetting resin composition of the present invention preferably has an exothermic peak of 100mW/g or more in a range of 160 ℃ to 200 ℃ inclusive, more preferably 180 ℃ to 200 ℃ inclusive, in an exothermic curve obtained by differential scanning calorimetry at a temperature rise rate of 5 ℃/min. The viscosity increase at a high temperature exceeding 80 ℃ can be suppressed by 160 ℃ or higher, and a good pot life can be obtained, and the reactivity is improved by 200 ℃ or lower, and the curing can be completed in a short time.

The thermosetting resin composition of the present invention has a viscosity when held at 80 ℃ for 120 minutes of preferably 1.0 to 3.0 times, more preferably 1.0 to 2.0 times the initial viscosity at 80 ℃ and a thickening ratio when held at 80 ℃ for 120 minutes of η, which is the viscosity when held at 80 ℃ for 1 minute (initial viscosity at 80 ℃), is measured^* ₁η viscosity at 80 ℃ for 120 minutes^* ₁₂₀From η^* ₁₂₀/η^* ₁The viscosity herein means a complex viscosity η obtained by measuring at a frequency of 0.5Hz and Gap1mm using a dynamic viscoelasticity measuring apparatus (ARES rheometer, TA インスツルメント Co., Ltd.) and a parallel plate having a diameter of 40mm^*。

The thickening ratio when the resin composition is held at 80 ℃ can be used as an index of the pot life of the thermosetting resin composition in the kneading step of the resin composition and the production step of the prepreg. That is, the smaller the thickening ratio when the resin composition is held at 80 ℃, the better the pot life. When the thickening ratio of the thermosetting resin composition is 1.0 times or more and 3.0 times or less when the composition is held at 80 ℃ for 120 minutes, the resin composition has high thermal stability, and the impregnation of the reinforcing fibers with the resin does not decrease in the prepreg production process, and voids are less likely to be generated in the molded article.

With respect to the adhesiveness of the prepreg, since it is affected by the contact area with the fine uneven portion on the surface of the adherend, if the storage elastic modulus of the matrix resin composition is low, the contact area increases, and the adhesiveness becomes good. In the dynamic viscoelasticity measurement at a frequency of 0.5Hz, if the storage elastic modulus at 30 ℃ is 0.1Pa or more and 100,000Pa or less, the prepreg has excellent adhesiveness and good adhesiveness between prepreg/metal and prepreg.

In the case of structural materials for aerospace applications, the surface becomes high temperature due to friction with air, and moisture in the moisture cloud is further absorbed, so that excellent mechanical properties and heat resistance are also required in a high-temperature environment after moisture absorption. Here, the mechanical properties of the cured thermosetting resin in a high-temperature environment after moisture absorption are the elastic modulus evaluated by a 3-point bending test in an environment of 82 ℃ after a test piece is immersed in hot water at 98 ℃ for 48 hours. The cured product obtained from the thermosetting resin composition of the present invention preferably has an elastic modulus of 3.0GPa or more, more preferably 3.2GPa or more, in a high-temperature environment after moisture absorption. The upper limit of the elastic modulus in a high-temperature environment after moisture absorption is not particularly limited, but is preferably as high as possible, but the upper limit of a general cured thermosetting resin is 7.0 GPa. The higher the flexural modulus of the cured thermosetting resin, the more excellent the mechanical properties as a fiber-reinforced composite material, and therefore, the higher the flexural modulus.

The heat resistance of the cured product after moisture absorption is the glass transition temperature of a test piece evaluated by a dynamic viscoelasticity test after being immersed in hot water at 98 ℃ for 48 hours. The glass transition temperature of a cured product obtained from the thermosetting resin composition of the present invention after moisture absorption is preferably 180 ℃ or higher, and more preferably 190 ℃ or higher. The upper limit of the glass transition temperature of the cured product after moisture absorption is not particularly limited, but is preferably as high as possible, but the upper limit of the cured product of a general thermosetting resin is 400 ℃. The higher the glass transition temperature of the cured thermosetting resin, the more applicable it is to members requiring higher heat resistance, and therefore, the higher the glass transition temperature, the more preferable it is.

In the present invention, it is also preferable to contain particles containing a thermoplastic resin as a main component. When the thermoplastic resin particles are contained, the toughness of a resin layer formed between layers made of reinforcing fibers (hereinafter, also referred to as an "interlayer resin layer") of the fiber-reinforced composite material is improved when the fiber-reinforced composite material is produced, and therefore, the impact resistance is improved.

As the thermoplastic resin particles, a thermoplastic resin which can be mixed with a thermosetting resin composition and used can be used, and among the polyamides, polyamide 12, polyamide 6, polyamide 11, polyamide 6/12 copolymer, and polyamide (semi-IPN polyamide) which is semi-IPN (polymer interpenetrating network structure) converted by an epoxy compound described in examples 1 to 7 of jp 2009-221460 a can obtain particularly good adhesive strength with a thermosetting resin. The thermoplastic resin particles may be spherical particles or non-spherical particles, or porous particles, but spherical particles are preferable because they do not lower the flow characteristics of the resin, and therefore, they have excellent viscoelasticity, and they have no stress concentration starting point, and can achieve high impact resistance. Commercially available polyamide particles include SP-500, SP-10, TR-1, TR-2, 842P-48, 842P-80 (manufactured by DOG レ, supra), "オルガソール (registered trademark)" 1002D, 2001UD, 2001EXD, 2002D, 3202D, 3501D, 3502D (manufactured by DOG アルケマ, supra). These polyamide particles may be used alone or in combination of two or more.

The thermosetting resin composition of the present invention may contain a coupling agent, thermosetting resin particles, or inorganic fillers such as silica gel, carbon black, clay, carbon nanotubes, graphene, carbon particles, and metal powder, in a range not to impair the effects of the present invention.

The prepreg of the present invention is obtained by compounding the above thermosetting resin composition as a matrix resin with reinforcing fibers. The reinforcing fibers include carbon fibers, graphite fibers, aramid fibers, glass fibers, and the like, and among them, carbon fibers are particularly preferable.

Commercially available carbon fibers include "トレカ" (registered trademark) T800G-24K, "トレカ" (registered trademark) T800S-24K, "トレカ" (registered trademark) T700G-24K, "トレカ" (registered trademark) T300-3K, and "トレカ" (registered trademark) T700S-24K (or more, manufactured by imperial レ K).

The form and arrangement of the carbon fibers may be appropriately selected from long fibers, woven fabrics, and the like aligned in one direction, but in order to obtain a carbon fiber-reinforced composite material that is lightweight and has a higher level of durability, the carbon fibers are preferably in the form of continuous fibers such as long fibers (fiber bundles) or woven fabrics aligned in one direction.

The prepreg of the present invention can be produced by various known methods. For example, the prepreg can be produced by a wet method in which a matrix resin is dissolved in an organic solvent selected from acetone, methyl ethyl ketone, methanol, and the like to reduce the viscosity thereof and impregnated into the reinforcing fibers, or a hot melt method in which a matrix resin is heated to reduce the viscosity thereof and impregnated into the reinforcing fibers without using an organic solvent.

In the wet method, a prepreg can be obtained by dipping reinforcing fibers in a liquid containing a matrix resin, pulling up the fibers, and evaporating an organic solvent using an oven or the like.

In the hot-melt method, a method of impregnating the reinforcing fibers with a matrix resin having a low viscosity by heating, or a method of preparing a release paper sheet with a resin film (hereinafter, sometimes referred to as "resin film") by first coating the matrix resin on a release paper or the like, then overlapping the resin film and the reinforcing fibers from both sides or one side of the reinforcing fibers, and heating and pressurizing the resin film to impregnate the reinforcing fibers with the matrix resin may be used.

In the method for producing a prepreg of the present invention, a hot-melt method is preferred in which reinforcing fibers are impregnated with a matrix resin without using an organic solvent so that the prepreg is substantially free from residual organic solvent.

The prepreg of the present invention preferably has a reinforcing fiber amount per unit area of 30 to 2,000g/m². If the amount of such reinforcing fibers is 30g/m²As described above, the number of laminated sheets for obtaining a predetermined thickness at the time of molding the fiber-reinforced composite material can be reduced, and the operation can be easily and simply performed. On the other hand, if the reinforcing fiber amount is 2,000g/m²The drape property of the prepreg is likely to be improved as follows.

The prepreg of the present invention preferably has a fiber mass content of 30 to 90 mass%, more preferably 35 to 85 mass%, and still more preferably 40 to 80 mass%. If the fiber mass content is 30 mass% or more, the amount of the resin is not excessive, and the advantage of the fiber-reinforced composite material having excellent specific strength and specific elastic modulus is easily obtained, and the heat release amount during curing is not easily excessively high at the time of molding the fiber-reinforced composite material. Further, if the fiber mass content is 90 mass% or less, impregnation failure of the resin is less likely to occur, and voids in the obtained fiber-reinforced composite material are likely to be reduced.

A first aspect of the fiber-reinforced composite material of the present invention is obtained by curing the prepreg of the present invention. The prepreg of the present invention can be produced by a method of laminating the prepregs in a predetermined form and curing the resin by applying pressure and heat. Here, as the method of imparting heat and pressure, for example, a press molding method, an autoclave molding method, a bag molding method, a wrapping tape method, an internal pressure molding method, or the like can be employed.

A second aspect of the fiber-reinforced composite material of the present invention is a fiber-reinforced composite material comprising reinforcing fibers and a cured thermosetting resin obtained by curing the thermosetting resin composition. The fiber-reinforced composite material of this embodiment can be produced by a method in which the reinforcing fiber is directly impregnated with the thermosetting resin composition of the present invention without using a prepreg, and then the resulting product is cured by heating, for example, a molding method such as a hand lay-up method, a filament winding method, a pultrusion molding method, a resin injection molding method, or a resin transfer molding method.