JP2021001245A - Fiber-reinforced epoxy resin composite material and fiber-reinforced plastic - Google Patents

Abstract

To provide: a fiber-reinforced epoxy resin composite material which can afford a fiber-reinforced plastic having extremely scarce voids and excellent mechanical properties; and a fiber-reinforced plastic using this fiber-reinforced epoxy resin composite material.SOLUTION: Provided is a fiber-reinforced epoxy resin composite material formed by impregnating reinforcing fibers with an epoxy resin composition containing an epoxy resin and a solvent by a hot-melt method, in which a content of the solvent is 0.02 mass% to 5 mass%. The epoxy resin is preferably an epoxy resin having a weight average molecular weight of 1500 or more, or a mixture of an epoxy resin having a weight average molecular weight of 1500 or more and an epoxy resin having a molecular weight of less than 1500, where a content of the epoxy resin having a weight average molecular weight of 1500 or more per 100 pts.mass of all epoxy resins is 60 pts.mass or more. The reinforcing fiber is preferably a carbon fiber. Also provided is a fiber-reinforced plastic comprising the fiber-reinforced epoxy resin composite material.SELECTED DRAWING: None

Description

The present invention relates to a fiber-reinforced epoxy resin composite material and a fiber-reinforced plastic using an epoxy resin as a matrix resin, and is suitably used for sports / leisure applications, general industrial applications, aircraft material applications, and the like. ..

Fiber reinforced plastic, which is one of the fiber reinforced composite materials, is lightweight, has high strength, and has high rigidity, so that it is widely used from sports / leisure applications to industrial applications such as automobiles and aircraft.

As a method for producing fiber reinforced plastic, there is a method of using an intermediate material, that is, a prepreg, in which a reinforcing material made of long fibers (continuous fibers) such as reinforcing fibers is impregnated with a matrix resin. According to this method, there is an advantage that the content of the reinforcing fiber of the obtained fiber reinforced plastic can be easily controlled and the content can be designed to be higher. By laminating a plurality of these prepregs and heat-curing them, a molded product of fiber reinforced plastic can be obtained.

Conventionally, due to the need for weight reduction, carbon fibers having excellent specific strength and specific elastic modulus have been widely used as reinforcing fibers, and thermosetting epoxy resins having excellent adhesion to carbon fibers have been often used as matrix resins.
However, since the cured product of a thermosetting epoxy resin is generally brittle and tends to have low impact resistance, it is an issue to improve the impact resistance of the fiber reinforced plastic using the thermosetting epoxy resin.

In addition, conventionally, when molding thermosetting fiber reinforced plastics for aircraft, an autoclave is used and it is cured over a long period of time under high temperature and high pressure, so that high strength can be obtained, but the molding time is long. The problem was low productivity. Further, the size of the molded product that can be manufactured is limited by the size of the autoclave, and although it is suitable for the production of high value-added thermosetting carbon fiber reinforced plastic, it is not suitable for mass production of general-purpose products.

For these reasons, de-autoclaving, especially the development of thermoplastic carbon fiber reinforced plastics, has been promoted, and Patent Document 1 describes sheet-shaped carbon obtained by impregnating a woven fabric containing carbon fibers with a thermoplastic epoxy resin. Fiber composites have been proposed.
In general, the thermoplastic resin composite material can be molded in a shorter time than the thermosetting resin composite material, so that the productivity is high and the cost can be reduced.

JP-A-2018-193457

In Patent Document 1, a large amount of solvent is used for impregnating the thermoplastic epoxy resin, and there is a problem that the mechanical properties of the obtained composite material vary because it is difficult to control the amount of the solvent. In addition, a large amount of voids are generated at the stage of volatilizing the solvent, and these voids remain at the stage of molding, which causes a decrease in the mechanical properties of the obtained composite material. Furthermore, since a thermoplastic epoxy resin having a low molecular weight is used, the impact resistance is also inferior.

The present invention has been made in view of the above background, and uses a fiber-reinforced epoxy resin composite material capable of obtaining a fiber-reinforced plastic having extremely few voids and excellent mechanical properties, and this fiber-reinforced epoxy resin composite material. The purpose is to provide fiber reinforced plastics.

As a result of diligent studies, the present inventors impregnate the reinforcing fibers with an epoxy resin composition containing an epoxy resin and a solvent by a hot melt method, thereby impregnating the reinforcing fibers with an epoxy resin using a very small amount of solvent. It has been found that the above-mentioned problems can be solved and a fiber-reinforced plastic having a desired performance can be provided, and the present invention has been reached.

That is, the gist of the present invention is as follows.

[1] A fiber-reinforced epoxy resin composite material obtained by impregnating reinforcing fibers with an epoxy resin composition containing an epoxy resin and a solvent by a hot melt method and having a solvent content of 0.02% by mass or more and 5% by mass or less.

[2] The fiber-reinforced epoxy resin composite material according to [1], wherein the epoxy resin is an epoxy resin having a weight average molecular weight of 1500 or more.

[3] The epoxy resin is a mixture of an epoxy resin having a weight average molecular weight of 1500 or more and an epoxy resin having a weight average molecular weight of less than 1500, and the proportion of the epoxy resin having a weight average molecular weight of 1500 or more in 100 parts by mass of the total epoxy resin is 60. The fiber-reinforced epoxy resin composite material according to [1], which is equal to or more than parts by mass.

[4] The fiber-reinforced epoxy resin composite material according to any one of [1] to [3], wherein the reinforcing fiber is a carbon fiber.

[5] A fiber-reinforced plastic using the fiber-reinforced epoxy resin composite material according to any one of [1] to [4].

[6] An epoxy resin film comprising an epoxy resin composition containing an epoxy resin and a solvent, wherein the solvent content in the film is 0.2% by mass or more and 10% by mass or less.

[7] The epoxy resin film according to [6], wherein the epoxy resin is an epoxy resin having a weight average molecular weight of 1500 or more.

[8] The epoxy resin is a mixture of an epoxy resin having a weight average molecular weight of 1500 or more and an epoxy resin having a weight average molecular weight of less than 1500, and the proportion of the epoxy resin having a weight average molecular weight of 1500 or more in 100 parts by mass of the total epoxy resin is 60. The epoxy resin film according to [6], which is at least a part by mass.

[9] A fiber-reinforced epoxy resin composite material obtained by heating and integrating a laminate of the epoxy resin film according to any one of [6] to [8] and a reinforcing fiber aggregate.

[10] A method for producing a fiber-reinforced epoxy resin composite material having a reinforcing fiber and an epoxy resin composition.
(A) An epoxy resin composition containing an epoxy resin and a solvent is prepared.
(B) The temperature of the prepared epoxy resin composition was adjusted in the range of 20 to 70 ° C. to form a coating film.
(C) The coating film was held at a temperature of 80 to 180 ° C. for 5 minutes to 3 hours to volatilize the solvent to prepare a resin film.
(D) The resin film is heat-bonded to the reinforcing fibers to impregnate the epoxy resin composition to produce a fiber-reinforced epoxy resin composite material having a solvent content of 0.02% by mass or more and 5% by mass or less. A method for manufacturing a fiber-reinforced epoxy resin composite material.

[11] The method for producing a fiber-reinforced epoxy resin composite material according to [10], wherein the epoxy resin is an epoxy resin having a weight average molecular weight of 1500 or more.

[12] The epoxy resin is a mixture of an epoxy resin having a weight average molecular weight of 1500 or more and an epoxy resin having a weight average molecular weight of less than 1500, and the proportion of the epoxy resin having a weight average molecular weight of 1500 or more in 100 parts by mass of the total epoxy resin is 60. The method for producing a fiber-reinforced epoxy resin composite material according to [10], which has a mass of parts or more.

According to the present invention, it is possible to provide a fiber reinforced plastic having extremely few voids and having excellent mechanical properties.

Hereinafter, the present invention will be described in detail.

In the present invention, the "epoxy resin" means a compound having two or more epoxy groups in one molecule.
Further, the "epoxy resin composition" means a resin composition containing an epoxy resin, a solvent, a curing agent, a curing accelerator, and a thermoplastic resin other than the epoxy resin, an additive, and the like.
In the present invention, the "solid content" means a component excluding the solvent, and includes not only a solid epoxy resin but also a semi-solid or a viscous liquid substance.

The weight average molecular weight (Mw) of the epoxy resin is a value measured as a polystyrene-equivalent value by gel permeation chromatography.
Further, the "epoxy equivalent" of an epoxy resin is defined as "the mass of an epoxy resin containing one equivalent of an epoxy group", and is defined as JIS.
It can be measured according to K7236.

In addition, "impregnation" generally means that a porous material such as cloth, paper, or wood is impregnated with a "liquid" such as a chemical, resin, or water. "Impregnated" means that the gaps between the reinforcing fibers are filled with the epoxy resin, not limited to the liquid.

[Fiber reinforced epoxy resin composite material]
The fiber-reinforced epoxy resin composite material (also referred to as "prepreg") of the present invention is obtained by impregnating reinforcing fibers with an epoxy resin composition containing an epoxy resin and a solvent by a hot melt method, and the content of the solvent is 0. It is characterized by having a value of .02% by mass or more and 5% by mass or less, and can be used as a raw material for a fiber-reinforced plastic having extremely few voids and excellent mechanical properties.

The fiber-reinforced epoxy resin composite material of the present invention can be produced by using an epoxy resin composition containing an epoxy resin as described later. Hereinafter, this epoxy resin composition may be referred to as "the epoxy resin composition of the present invention", and the epoxy resin in the epoxy resin composition of the present invention may be referred to as "the epoxy resin of the present invention".

In the present invention, a thermoplastic epoxy resin is used as the epoxy resin.
Epoxy resins include thermosetting epoxy resins and thermoplastic epoxy resins. Of these, the thermoplastic epoxy resin is used in the present invention.
The epoxy resin is generally a typical resin of a thermosetting resin. The thermosetting epoxy resin has a relatively low molecular weight, whereas the thermoplastic epoxy resin used in the present invention has a high molecular weight to impart thermoplasticity to the epoxy resin.

<Epoxy resin>
The epoxy resin of the present invention is not particularly limited as long as it is thermoplastic, and known ones can be used.
As the epoxy resin of the present invention, an epoxy resin having a weight average molecular weight of 1500 or more is preferable.
Further, the epoxy resin of the present invention may be a mixture of an epoxy resin having a weight average molecular weight of 1500 or more and an epoxy resin having a weight average molecular weight of less than 1500.

The content of the epoxy resin in the epoxy resin composition (including solid content and solvent) of the present invention is preferably 25% by mass or more, particularly 30% by mass or more, and 85% by mass or less, particularly 80% by mass or less. .. The content of the epoxy resin depends on the viscosity of the epoxy resin, the type of solvent, the content of the curing agent, etc., but if the content of the epoxy resin is equal to or higher than the above lower limit, the solvent is likely to volatilize during film formation. Preferably, if it is not more than the above upper limit, it is easy to handle when forming a film, which is preferable.

(Epoxy resin with a weight average molecular weight of 1500 or more)
By using an epoxy resin having a weight average molecular weight of 1500 or more as the epoxy resin of the present invention, a fiber reinforced plastic having excellent impact resistance can be obtained.
As the epoxy resin of the present invention, an epoxy resin having a weight average molecular weight of 1500 or more and an epoxy resin having a weight average molecular weight of less than 1500 may be used in combination. In this case, the ratio of the epoxy resin having a weight average molecular weight of 1500 or more to 100 parts by mass of the epoxy resin of the present invention is preferably 60 parts by mass or more, more preferably 65 parts by mass or more, still more preferably 70 parts by mass or more, and particularly preferably 70 parts by mass or more. It is 90 parts by mass or more, and the upper limit thereof is preferably 100 parts by mass. As the proportion of the epoxy resin having a weight average molecular weight of 1500 or more is larger than the above lower limit, it tends to be possible to obtain a fiber reinforced plastic having excellent impact resistance.

When all the epoxy resins of the present invention are composed of epoxy resins having a weight average molecular weight of less than 1500, they tend to be insufficient for film formation and impact resistance. However, if the weight average molecular weight of the epoxy resin exceeds 100,000, it tends to be difficult to handle the resin due to its high viscosity.
From the viewpoint of film formation, impact resistance and resin handling, the weight average molecular weight of an epoxy resin having a weight average molecular weight of 1500 or more is preferably 2000 or more, preferably 100,000 or less, and more preferably 80,000 or less. ..

The epoxy equivalent of an epoxy resin having a weight average molecular weight of 1500 or more is preferably 800 to 50,000 g / eq, particularly preferably 850 to 40,000 g / eq. If the epoxy equivalent is at least the above lower limit, film formation is easy and impact resistance is easily exhibited, and if it is at least the above upper limit, the resin is easy to handle, which is preferable.

An epoxy resin having a weight average molecular weight of 1500 or more can be produced by using a general method for producing a thermoplastic epoxy resin, and for example, a divalent phenol compound having an aromatic structure and / or an alicyclic structure, preferably. It can be obtained by combining a divalent phenol compound having an aromatic structure and an alicyclic structure with a bifunctional epoxy resin and subjecting them to a heat addition reaction in the presence of a catalyst.

The divalent phenol compound having an aromatic structure and an alicyclic structure is not particularly limited, but 1,1-bis (4-hydroxyphenyl) cyclohexane and bis (4-hydroxyphenyl) -3,3,5- Trimethylcyclohexane or the like can be preferably used. Only one of these may be used, or two or more thereof may be used in combination. Among them, bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane is particularly preferable. The bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane used is preferably 96% or more in purity, preferably 98% or more. If the purity is less than 96%, it may not be possible to sufficiently achieve high molecular weight.

As the raw material dihydric phenol compound, another divalent phenol compound may be used in combination with the divalent phenol compound having the above aromatic structure and alicyclic structure. In that case, the other divalent phenol compound may be used. Any compound may be used as long as the two hydroxyl groups are bonded to an aromatic ring. Examples thereof include bisphenols such as bisphenol A, bisphenol F, bisphenol S, bisphenol B and bisphenol AD, biphenol, catechol, resorcin, hydroquinone, dihydroxynaphthalene and the like. Further, those substituted with non-interfering substituents such as an alkyl group, an aryl group, an ether group and an ester group may be used. Among these divalent phenol compounds, preferred are bisphenol A, bisphenol F, bisphenol S, 4,5'-biphenol, 3,3', 5,5'-tetramethyl-4,4'-biphenol. .. As the other divalent phenol compound, only one kind may be used, or two or more kinds may be used in combination.

When these other divalent phenol compounds are used in combination, the amount used should be 30% by mass or less of the total divalent phenol compounds used as the raw material, that is, 70 to 100% by mass of the raw material divalent phenol compound is aromatic. It is preferably a dihydric phenol compound having a group structure and an alicyclic structure.

On the other hand, the raw material bifunctional epoxy resin may be any compound having two epoxy groups in the molecule, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin and the like. Bisphenol type epoxy resin, biphenol type epoxy resin, alicyclic epoxy resin, catechol, resorcin, hydroquinone and other monocyclic divalent phenol diglycidyl ether, dihydroxynaphthalene diglycidyl ether, dihydric alcohol diglycidyl ether, phthal Examples thereof include diglycidyl esters of divalent carboxylic acids such as acids, isophthalic acids, tetrahydrophthalic acids, and hexahydrophthalic acids. Further, those substituted with non-interfering substituents such as an alkyl group, an aryl group, an ether group and an ester group may be used. Only one kind of these raw material bifunctional epoxy resins may be used, or two or more kinds may be used in combination.

The equivalent ratio of the raw material bifunctional epoxy resin and the divalent phenol compound at the time of reaction is preferably epoxy group: phenolic hydroxyl group = 1: 0.99 to 1.10. Even if this equivalent ratio is smaller than 0.90 or larger than 1.10, it may not be possible to sufficiently increase the molecular weight. Although it depends on the reaction conditions, when the epoxy group: phenolic hydroxyl group is less than 1: 1, the terminal becomes an epoxy group, and when the epoxy group: phenolic hydroxyl group = 1: 1 or more, the terminal becomes a phenolic hydroxyl group. The probability of becoming is high.

As the epoxy resin having a weight average molecular weight of 1500 or more, a commercially available product may be used.
Epoxy resins available as commercially available products are not limited to the following, but are not limited to jER1055, jER1004, jER1007, jER1009, jER1010, jER1256, jER4250, jER4275, jER1256B40, jER1255HX30, YX8100BH30, YX6954BH30, YX7200BH30, YX7200BH30, YX7200B35 Also traded by Mitsubishi Chemical Co., Ltd.), EPICLON3050, EPICLON4050, EPICLON7050, EPICLON HM-091, EPICLON HM-101 (trade name, manufactured by DIC Corporation), YD-903N, YD-904, YD-907. , YD-7910, YD-6020, YP-50, YP-50S, YP-70, ZX-1356-2, FX-316, YDF2004, YDF-2005RD (trade names, all manufactured by Nippon Steel & Sumikin Chemical & Materials Co., Ltd.) ) Etc. can be mentioned.

As for the epoxy resin having a weight average molecular weight of 1500 or more, one of these may be used alone, or two or more of them may be used in combination.

(Epoxy resin with a weight average molecular weight of less than 1500)
As the epoxy resin of the present invention, an epoxy resin having a weight average molecular weight of less than 1500 may be used together with an epoxy resin having a weight average molecular weight of 1500 or more as long as the object of the present invention is not impaired. By using an epoxy resin having a weight average molecular weight of less than 1500, preferably 1300 or less, the strength, elastic modulus, heat resistance, and handleability of the obtained fiber-reinforced plastic can be improved.
However, if the molecular weight of the epoxy resin having a weight average molecular weight of less than 1500 is excessively small, the epoxy resin tends to volatilize, and the epoxy resin is repelled on the surface of the release film or the release paper, making it impossible to produce a resin film. The lower limit of the weight average molecular weight of the epoxy resin having a molecular weight of less than 1500 is preferably 200 or more, particularly 250 or more.
Further, the epoxy equivalent of the epoxy resin having a weight average molecular weight of less than 1500 is preferably 90 to 800 g / eq, particularly preferably 100 to 750 g / eq. When the epoxy equivalent is not less than the above lower limit, it becomes easy to produce a resin film, and when it is not more than the above upper limit, heat resistance, strength and elastic modulus can be improved while imparting toughness, which is preferable.

When an epoxy resin having a weight average molecular weight of 1500 or more and an epoxy resin having a weight average molecular weight of less than 1500 are used in combination as the epoxy resin of the present invention, the above-mentioned effect by using the epoxy resin having a weight average molecular weight of 1500 or more can be effectively obtained. The ratio of the epoxy resin having a weight average molecular weight of less than 1500 to 100 parts by mass of the epoxy resin of the present invention is preferably 40 parts by mass or less, more preferably 35 parts by mass or less, still more preferably 30 parts by mass or less, and particularly preferably 10 parts by mass. It is less than or equal to parts, and its lower limit is 0 parts by mass.

The epoxy resin having a weight average molecular weight of less than 1500 is not particularly limited, but a bifunctional or higher functional epoxy resin is preferably used. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, bisphenol S type epoxy resin, bisphenol E type epoxy resin, bisphenol Z type epoxy resin, bisphenol AD type epoxy resin and other bisphenol type epoxy resins, Biphenyl type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, trisphenol methane type epoxy resin, tetraglycidyl diaminodiphenyl methane, glycidyl amine such as triglycidyl aminophenol Type epoxy resin; glycidyl ether type epoxy resin other than the above such as tetrakis (glycidyloxyphenyl) ethane and tris (glycidyloxy) methane, and modified epoxy resin, phenol aralkyl type epoxy resin, alicyclic epoxy, etc. Can be mentioned.
Since trifunctional or higher functional epoxy resins can obtain better strength, elasticity, and heat resistance, para-type and meta-type triglycidyl aminophenol type epoxy resins, tetraglycidyl diaminodiphenylmethane type epoxy resins, and phenol novolac type epoxys can be obtained. Resins and cresol novolac type epoxy resins are preferably used.

Commercially available products of epoxy resins with a weight average molecular weight of less than 1500 include, but are not limited to, jER825 (epoxy equivalent 175 g / eq), jER827 (epoxy equivalent 185 g / eq), jER828 (epoxy equivalent 189 g / eq), jER834 (epoxy). Equivalent 250 g / eq), jER806 (epoxy equivalent 165 g / eq), jER807 (epoxy equivalent 170 g / eq), jER604 (epoxy equivalent 120 g / eq), jER630 (epoxy equivalent 98 g / eq), jER1032H60 (epoxy equivalent 169 g / eq) , JER152 (epoxy equivalent 175 g / eq), jER154 (epoxy equivalent 178 g / eq), jER157S70 (epoxy equivalent 210 g / eq), YX-7700 (epoxy equivalent 273 g / eq), YX-8000 (epoxy equivalent 205 g / eq), YX-8800 (epoxy equivalent 179 g / eq), YX-4000 (epoxy equivalent 186 g / eq), YX-7105 (epoxy equivalent 480 g / eq), YX-7400 (epoxy equivalent 440 g / eq) (all trade names, Mitsubishi Made by Chemical Co., Ltd.), YD-127 (epoxy equivalent 185 g / eq), YD-128 (epoxy equivalent 189 g / eq), YDF-170 (epoxy equivalent 170 g / eq), YDPN-638 (epoxy equivalent 180 g / eq), TX-0911 (epoxy equivalent 172g / eq) (trade name, manufactured by Nippon Steel & Sumitomo Metal Chemical & Materials Co., Ltd.), EPICLON840 (epoxy equivalent 185g / eq), EPICLON850 (epoxy equivalent 189g / eq), EPICLON830 (epoxy equivalent 170g / eq) eq), EPICLON835 (epoxy equivalent 172g / eq), HP-4032 (epoxy equivalent 150g / eq), HP-4700 (epoxy equivalent 162g / eq), HP-4770 (epoxy equivalent 204g / eq), HP-4750 (epoxy) Equivalent 185 g / eq), HP-7200 (epoxy equivalent 265 g / eq), N-730A (epoxy equivalent 174 g / eq), N-740 (epoxy equivalent 181 g / eq), N-770 (epoxy equivalent 187 g / eq), TSR-400 (epoxy equivalent 338 g / eq) (trade name, manufactured by DIC Co., Ltd.), GAN (epoxy equivalent 125 g / eq), GOT (epoxy equivalent 135 g / eq), NC-2000 (epoxy equivalent 241 g / eq) , NC -3000 (epoxy equivalent 275 g / eq) (trade name, manufactured by Nippon Kayaku Co., Ltd.), MY-0500 (epoxy equivalent 110 g / eq), MY-0600 (epoxy equivalent 106 g / eq), ECN-1299 (epoxy) Equivalent 230 g / eq) (both trade names, manufactured by Huntsman Japan Co., Ltd.), D.I. E. R331, D.I. E. R354 (epoxy equivalent 170 g / eq) (epoxy equivalent 187 / eq), D.I. E. Examples thereof include R332 (epoxy equivalent 173 g / eq) (both trade names, manufactured by THE DOW CHEMICAL COMPANY).
As the epoxy resin having a weight average molecular weight of less than 1500, one of these may be used alone, or two or more of them may be used in combination.

<Solvent>
The epoxy resin composition of the present invention preferably contains a solvent in order to appropriately adjust the viscosity at the time of handling such as impregnation of reinforcing fibers. The solvent is used for impregnating the reinforcing fibers with the epoxy resin composition of the present invention, or for ensuring the handleability and workability when producing the epoxy resin film of the present invention described later, and the content thereof is adjusted. Is not particularly limited, but it is usually preferable that the epoxy resin composition of the present invention is prepared so that the solid content concentration is 25 to 85% by mass, particularly 30 to 80% by mass.

The solvent contained in the epoxy resin composition of the present invention is not particularly limited, and for example, acetone, methyl ethyl ketone, toluene, xylene, methyl isobutyl ketone, ethyl acetate, butyl acetate, propyl acetate, cyclohexanone, ethylene glycol monomethyl ether, ethylene. Glycolmonomethyl ether acetate, N, N-dimethylformamide, N, N-dimethylacetamide, methanol, ethanol and the like can be mentioned. These solvents can be appropriately used as a mixed solvent of two or more kinds.

<Hardener>
The epoxy resin composition of the present invention may contain a curing agent. The curing agent is used for strength, elastic modulus, heat resistance, adhesion to reinforcing fibers, and the like.
The curing agent used in the present invention is not particularly limited, and for example, dicyandiamide, ureas, imidazoles, aromatic amines, other amine-based curing agents, acid anhydrides, boron chlorideamine complexes, phenols, organic phosphine compounds, etc. Acid anhydrides, benzoxazines and the like can be used.

Since dicyandiamide has a high melting point and its compatibility with an epoxy resin is suppressed in a low temperature region, it is preferable to use it as a curing agent because an epoxy resin composition having an excellent pot life tends to be obtained. Further, the inclusion of dicyandiamide tends to improve the mechanical characteristics of the cured resin product, which is preferable.

When the epoxy resin composition of the present invention contains dicyandiamide as a curing agent, the content thereof is the activity of dicyandiamide with respect to the total number of moles of epoxy groups contained in the epoxy resin of the present invention contained in the epoxy resin composition of the present invention. The amount is preferably such that the number of moles of hydrogen is 0.4 to 1 times. By setting the molar ratio to 0.4 times or more, a cured product having good heat resistance and good mechanical properties (that is, high strength and elastic modulus) tends to be obtained. Further, by setting the value to 1 times or less, a cured product having good mechanical properties (that is, excellent in plastic deformation ability and impact resistance) tends to be obtained. Further, by increasing the number of moles of active hydrogen of this dicyandiamide to 0.5 to 0.8 times, the heat resistance of the cured product tends to be more excellent, which is more preferable.

Examples of commercially available dicyandiamides include, but are not limited to, DICY7, DICY15 (trade name, manufactured by Mitsubishi Chemical Corporation), and DICYANEX1400F (trade name, manufactured by Air Products & Chemicals, Inc.).

Ureas are not particularly limited as long as they have a dimethylureido group in the molecule and generate an isocyanate group and dimethylamine by heating at a high temperature, and these activate the epoxy resin of the present invention. For example, aromatic dimethylurea in which a dimethylureido group is bonded to an aromatic ring, aliphatic dimethylurea in which a dimethylureido group is bonded to an aliphatic compound, and the like can be mentioned. Among these, aromatic dimethylurea is preferable because the curing rate tends to be high and the heat resistance and bending strength of the cured product tend to be high.
As the aromatic dimethylurea, for example, phenyldimethylurea, methylenebis (phenyldimethylurea), trilenbis (dimethylurea) and the like are preferably used. Specific examples include 4,4'-methylenebis (phenyldimethylurea) (MBPDMU), 3-phenyl-1,1-dimethylurea (PDMU), 3- (3,4-dichlorophenyl) -1,1-dimethylurea. (DCMU), 3- (3-chloro-4-methylphenyl) -1,1-dimethylurea, 2,4-bis (3,3-dimethylureido) toluene (TBDMU), m-xylylene diisocyanate and dimethylamine Examples include dimethylurea obtained from. Among these, DCMU, MBPDMU, TBDMU, and PDMU are more preferable from the viewpoint of curing acceleration ability and imparting heat resistance to the cured resin product. These may be used individually by 1 type and may be used in combination of 2 or more type.

Examples of the aliphatic dimethylurea include dimethylurea obtained from isophorone diisocyanate and dimethylamine, and dimethylurea obtained from hexamethylene diisocyanate and dimethylamine.

Commercially available products can also be used as ureas. Examples of commercially available DCMU products include, but are not limited to, DCMU-99 (trade name, manufactured by Hodogaya Chemical Co., Ltd.).
Examples of commercially available MBPDMU products include Technology MDU-11 (trade name, manufactured by A & C Catalysts); Omicure 52 (trade name, manufactured by PIT Japan Co., Ltd.). It is not limited.
Examples of commercially available PDMU products include, but are not limited to, Omicure 94 (trade name, manufactured by PIT Japan Co., Ltd.).
Examples of commercially available TBDMU products include Omicure 24 (trade name, manufactured by PIT Japan Co., Ltd.) and U-CAT 3512T (trade name, manufactured by Sun Appro Co., Ltd.). It is not limited.
Examples of commercially available aliphatic dimethylurea products include, but are not limited to, U-CAT 3513N (trade name, manufactured by Sun Appro Co., Ltd.).

When the epoxy resin composition of the present invention contains ureas as a curing agent, the content thereof is 1 to 15 parts by mass with respect to 100 parts by mass of the epoxy resin of the present invention contained in the epoxy resin composition of the present invention. Preferably, 2 to 10 parts by mass is more preferable. When the content of ureas is 1 part by mass or more, the epoxy resin contained in the epoxy resin composition tends to be sufficiently cured and cured, and the mechanical properties and heat resistance can be improved. On the other hand, when the content of ureas is 15 parts by mass or less, the toughness of the obtained cured product tends to be maintained high.

The imidazoles may be imidazole, and imidazole adduct, inclusion imidazole, microcapsule type imidazole, imidazole compound coordinated with a stabilizer, and the like can also be used.
They have a nitrogen atom having an unshared electron pair in their structure, which can activate the epoxy group of the epoxy resin of the present invention and promote curing and curing.

Specific examples of the imidazole include 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecyl imidazole, 2-heptadecyl imidazole, 1,2-dimethyl imidazole, 2-phenyl imidazole, 2-phenyl-4. -Methylimidazole, 1-benzyl-2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2- Undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazolium trimerite, 1-cyanoethyl-2-undecylimidazolium trimerite, 1-cyanoethyl-2- Phenylimidazolium trimellitate, 2,4-diamino-6- (2'-methylimidazolyl- (1'))-ethyl-s-triazine, 2,4-diamino-6- (2'-undecylimidazolyl- (1'))-Ethyl-s-triazine, 2,4-diamino-6- (2'-ethyl-4-methylimidazolyl- (1'))-ethyl-s-triazine, 2,4-diamino-6 -(2'-Methylimidazolyl- (1'))-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-methylimidazole isocyanuric acid adduct, 1-cyanoethyl-2 Examples of this include -phenyl-4,5-di (2-cyanoethoxy) methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole and the like. It is not limited.
The imidazole treated with adduct treatment, inclusion treatment with a different molecule, microcapsule treatment, or coordinated with a stabilizer is a modification of the above-mentioned imidazole. By reducing the activity of imidazole by adduct treatment, inclusion treatment with different molecules, microcapsule treatment, or by coordinating a stabilizer, it promotes hardening and hardening while exhibiting excellent pot life in the low temperature region. High ability.

Commercially available products may be used as the imidazoles. Commercially available products of imidazole include 2E4MZ, 2P4MZ, 2PZ-CN, C11Z-CNS, C11Z-A, 2MZA-PW, 2MA-OK, 2P4MHZ-PW, 2PHZ-PW (both trade names, manufactured by Shikoku Chemicals Corporation). However, the present invention is not limited to these.
Commercially available products of imidazole adduct include, for example, PN-50, PN-50J, PN-40, PN-40J, PN-31, and PN-23, which have a structure in which an imidazole compound is ring-opened and added to an epoxy group of an epoxy resin. , PN-H (both are trade names and manufactured by Ajinomoto Fine-Techno Co., Ltd.), but are not limited thereto.
Commercially available products of inclusion imidazole include, for example, TIC-188, KM-188, HIPA-2P4MHZ, NIPA-2P4MHZ, TEP-2E4MZ, HIPA-2E4MZ, NIPA-2E4MZ (all trade names, manufactured by Nippon Soda Corporation). However, the present invention is not limited to these.
Examples of commercially available microcapsule type imidazole include Novacure HX3721, HX3722, HX3742, HX3748 (trade name, manufactured by Asahi Kasei E-Materials Co., Ltd.); LC-80 (trade name, manufactured by A & C Catalysts). However, it is not limited to these.

The imidazole compound coordinated with the stabilizer is, for example, a cure duct P-0505 (bisphenol A diglycidyl ether / 2-ethyl-4-methylimidazole adduct), which is an imidazole adduct manufactured by Shikoku Kasei Kogyo Co., Ltd. It can be prepared by combining L-07N (epoxy-phenol-boric acid ester compound), which is a stabilizer manufactured by Shikoku Kasei Kogyo Co., Ltd. Similar effects can be obtained by using imidazole compounds such as various imidazoles and imidazole adducts mentioned above instead of the cure duct P-0505. As the imidazole compound before coordinating the stabilizer, a compound having low solubility in an epoxy resin is preferably used, and from this point of view, Cure Duct P-0505 is preferable.

When the epoxy resin composition of the present invention contains imidazoles as a curing agent, the content thereof is 1 to 15 parts by mass with respect to 100 parts by mass of the epoxy resin of the present invention contained in the epoxy resin composition of the present invention. Preferably, 2 to 10 parts by mass is more preferable. When the content of imidazoles is 1 part by mass or more, the epoxy resin contained in the epoxy resin composition tends to have sufficient curing, curing promoting action, and heat resistance. On the other hand, when the content of imidazoles is 15 parts by mass or less, a cured product having better mechanical properties tends to be obtained.

Examples of aromatic amines include 3,3'-diisopropyl-4,4'-diaminodiphenylmethane, 3,3'-di-t-butyl-4,4'-diaminodiphenylmethane, and 3,3'-diethyl-. 5,5'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-diisopropyl-5,5'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-di-t-butyl-5,5 5'-dimethyl-4,4'-diaminodiphenylmethane, 3,3', 5,5'-tetraethyl-4,4'-diaminodiphenylmethane, 3,3'-diisopropyl-5,5'-diethyl-4,4 '-Diaminodiphenylmethane, 3,3'-di-t-butyl-5,5'-diethyl-4,4'-diaminodiphenylmethane, 3,3', 5,5'-tetraisopropyl-4,4'-diamino Diphenylmethane, 3,3'-di-t-butyl-5,5'-diisopropyl-4,4'-diaminodiphenylmethane, 3,3', 5,5'-tetra-t-butyl-4,4'-diamino Examples thereof include diphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, m-phenylenediamine, m-xylylene diamine, diethyltoluenediamine and the like. It is not limited. Among them, it is preferable to use 4,4'-diaminodiphenyl sulfone and 3,3'-diaminodiphenyl sulfone, which are excellent in heat resistance and elastic modulus and can obtain a cured product having a small decrease in heat resistance due to linear expansion coefficient and moisture absorption. .. 4,4'-diaminodiphenyl sulfone is also preferable in that the tack life of the prepreg can be maintained for a long period of time. Although 3,3'-diaminodiphenyl sulfone may be inferior to 4,4'-diaminodiphenyl sulfone in the tack life of the prepreg and the heat resistance of the cured product, it is preferable because it can increase the elastic modulus and toughness of the cured product. .. Further, it is preferable to mix 4,4'-diaminodiphenyl sulfone and 3,3'-diaminodiphenyl sulfone at the same time because the heat resistance and elastic modulus of the cured product can be easily adjusted. These aromatic amines may be used alone or in combination as appropriate.

Commercially available products may be used as the aromatic amines. Commercially available products of 4,4'-diaminodiphenyl sulfone include Seika Cure S (active hydrogen equivalent 62 g / eq, trade name, manufactured by Wakayama Seika Kogyo Co., Ltd.), Sumi Cure S (active hydrogen equivalent 62 g / eq, trade name, Sumitomo Chemical). , Etc., as a commercially available product of 3,3'-diaminodiphenyl sulfone, 3,3'-DAS (active hydrogen equivalent 62 g / eq, trade name, manufactured by Mitsui Kagaku Fine Co., Ltd.) and the like can be mentioned. Not limited to these.
Other commercially available aromatic amines include MDA-220 (active hydrogen equivalent 50 g / eq, trade name, manufactured by Mitsui Chemicals, Inc.), "jER Cure (registered trademark)" W (active hydrogen equivalent 45 g / eq,). Mitsubishi Chemical Co., Ltd., Lonzacure (registered trademark) M-DEA (active hydrogen equivalent 78 g / eq), "Lonzacure (registered trademark)" M-DIPA (active hydrogen equivalent 92 g / eq), "Lonzacure (registered trademark)" Examples include, but are not limited to, M-MIPA (active hydrogen equivalent 78 g / eq) and “Lonzacure®” DETDA 80 (active hydrogen equivalent 45 g / eq) (all manufactured by Lonza Co., Ltd.).

When the epoxy resin composition of the present invention contains aromatic amines as a curing agent, the content thereof, especially in diaminodiphenyl sulfone, is the active hydrogen equivalent number of the amino group of the epoxy resin composition of the present invention. It is preferably 0.5 to 1.5 times, more preferably 0.6 to 1.4 times, the epoxy equivalent number of all the epoxy resins contained in. Within this range, the elastic modulus, toughness and heat resistance of the obtained cured product tend to be in a good range.

Examples of acid anhydrides include a dicarboxylic acid compound having one cyclic acid anhydride group (-C (O) OC (O)-) in one molecule, and two cyclic acid anhydride groups in one molecule. Examples thereof include tetracarboxylic acid compounds having one. Specifically, dodecenyl succinic anhydride, polyadipic anhydride, polyazelineic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylhymic anhydride, hexahydrophthalic anhydride, phthalic anhydride, anhydrous. Trimellitic anhydride, 3-acetamidophthalic anhydride, 4-pentene-1,2-dicarboxylic anhydride, 6-bromo-1,2-dihydro-4H-3,1-benzoxazine-2,4-dione, 2,3-Anthracendicarboxylic anhydride, benzophenone tetracarboxylic anhydride, 3,3', 4,4'
-Biphenyltetracarboxylic dianhydride and the like can be mentioned. These may be used alone or in combination of two or more.

When the epoxy resin composition of the present invention contains an acid anhydride as a curing agent, the content thereof is the acid group of the acid anhydride with respect to the epoxy equivalent number of the epoxy resin of the present invention in the epoxy resin composition of the present invention. The ratio of the number of equivalents of the above is preferably 0.5 to 1.5, more preferably 0.6 to 1.4, and even more preferably 0.7 to 1.3.

Since phenols generally increase the crosslink density of the cured product, a cured product having excellent heat resistance, moisture resistance, chemical resistance, etc. can be obtained by using the phenols.
Commercially available products may be used as the phenols, TD-2131, TD-2106, TD-2093, TD-2091, TD-2090, VH-4150, VH-4170, KH-6021, KA-1160, KA-1163, KA-1165 (trade name, manufactured by DIC Co., Ltd.), MR-970N, MR-600, MR-970, MR-506, MR-860, MR-3307, MR-583, MR-757, MR- 508, MR-110, MR-750, MR-550M, MR-5809, MR-750N, M-1, MR-552, MR-130, MR-2015, MR-320, MR-2014, MR-2018, MR-3413, MR-3405, MR-506C, MR-3424, MWR-204, MWR-102E, MWR-202L, MR-332, MWR-102EM, MWR-1223, MWR-202, MWR-2205, MWR- Examples include, but are not limited to, 102G, MWR-1201, MW-201 (all trade names, manufactured by Meiwa Kasei Co., Ltd.).

When the epoxy resin composition of the present invention contains phenols as a curing agent, the content thereof is the epoxy resin of the present invention in which the number of active hydrogen equivalents of the hydroxyl groups of the phenols is contained in the epoxy resin composition of the present invention. The amount is preferably 0.5 to 1.5 times the epoxy equivalent number of the above, and more preferably 0.6 to 1.4 times. By setting this ratio in the above range, the elastic modulus, toughness, and heat resistance of the obtained cured product tend to be in a good range.

Specific examples of the organic phosphine compound include tri-n-propylphosphine, tri-n-butylphosphine, triphenylphosphine, tetramethylphosphonium bromide, tetramethylphosphonium iodide, tetramethylphosphonium hydroxide, trimethylcyclohexylphosphonium chloride, and trimethyl. Cyclohexylphosphonium bromide, trimethylbenzylphosphonium chloride, trimethylbenzylphosphonium bromide, tetraphenylphosphonium bromide, triphenylmethylphosphonium bromide, triphenylmethylphosphonium iodide, triphenylethylphosphonium chloride, triphenylethylphosphonium bromide, triphenylethylphosphonium iodide , Triphenylbenzylphosphonium chloride, triphenylbenzylphosphonium bromide and the like, but are not limited thereto.

When the epoxy resin composition of the present invention contains an organic phosphine compound as a curing agent, the content thereof is 0.1 to 5 with respect to 100 parts by mass of the epoxy resin of the present invention contained in the epoxy resin composition of the present invention. By mass is preferable, and 0.5 to 3 parts by mass is more preferable. When the content of the organic phosphine compound is 0.1 part by mass or more, the epoxy resin contained in the epoxy resin composition tends to have sufficient curing, curing promoting action, and heat resistance. On the other hand, when the content of the organic phosphine compound is 5 parts by mass or less, a cured product having better mechanical properties tends to be obtained.

In benzoxazines, the oxazine ring is opened by heat to generate a phenolic hydroxyl group, and like phenols, the crosslink density of the cured product is generally increased. Therefore, by using this, heat resistance, moisture resistance, and flame retardancy are used. A cured product having excellent properties, chemical resistance, etc. can be obtained.
Available benzoxazines include benzoxazine F-a, benzoxazine P-d (trade name, manufactured by Shikoku Kasei Kogyo Co., Ltd.), JBZ-OP100N, JBZ-BP100N (trade name, all JFE Chemical Co., Ltd.). (Company), BF-BXZ, BS-BXZ (all product names, manufactured by Konishi Chemical Industry Co., Ltd.), CR-276 (all product names, manufactured by Tohoku Kako Co., Ltd.), etc., but are not limited to these. ..

When the epoxy resin composition of the present invention contains benzoxazines as a curing agent, the content thereof is the number of active hydrogen equivalents of hydroxyl groups generated when the benzoxazines are heated, and the epoxy resin composition of the present invention. The amount is preferably 0.3 to 3.0 times the epoxy equivalent of the epoxy resin of the present invention contained in the above, and more preferably 0.4 to 2.5 times. preferable. By setting this ratio in the above range, the elastic modulus, toughness, and heat resistance of the obtained cured product tend to be in a good range.

<Thermoplastic resin>
The epoxy resin composition of the present invention may contain a thermoplastic resin other than the epoxy resin, if necessary, for the purpose of imparting functions such as resin flow control and toughness when the reinforcing fibers are impregnated.

Examples of thermoplastic resins other than epoxy resins include polyamide, polyester, polycarbonate, polyethersulfone, polyphenylene ether, polyphenylene sulfide, polyetheretherketone, polyetherketone, polyimide, polytetrafluoroethylene, polyether, polyolefin, and liquid crystal polymer. , Polyallylate, polysulfone, polyacrylonitrile styrene, polystyrene, polyacrylonitrile, polymethylmethacrylate, ABS, AES, ASA, polyvinyl chloride, polyvinylformal resin, block polymer and the like, but are not limited thereto.

Among these, polyether sulfone and polyvinyl formal resins are preferable because they are excellent in resin flow controllability and the like. Further, polyether sulfone is preferable from the viewpoint of further enhancing the heat resistance and flame retardancy of the epoxy resin composition, and polyvinylformal resin is suitable for tacking the obtained prepreg without impairing the heat resistance of the epoxy resin composition. It is preferable from the viewpoint that the range can be easily controlled and the adhesiveness between the reinforcing fiber and the epoxy resin composition is improved. Block polymers are preferred because they improve toughness and impact resistance.

As the polyvinyl formal resin, Vinilek (registered trademark) K (average molecular weight: 59,000), Vinilek L (average molecular weight: 66,000), Vinilek H (average molecular weight: 73,000), Vinilec E (average molecular weight: 126). 000) (both are trade names, manufactured by JNC Corporation) and the like, but are not limited thereto.

When the obtained fiber-reinforced plastic is required to have heat resistance exceeding 180 ° C., a polyether sulfone or a polyetherimide is preferably used as the thermoplastic resin. Specifically, as polyether sulfones, Sumika Excel (registered trademark) 3600P (average molecular weight: 16,400), Sumika Excel 5003P (average molecular weight: 30,000), Sumika Excel 5200P (average molecular weight: 35,000), Examples thereof include Sumika Excel 7600P (average molecular weight: 45,300) (all manufactured by Sumitomo Chemical Co., Ltd.). Examples of the polyetherimide include ULTEM1000 (average molecular weight: 32,000), ULTEM1010 (average molecular weight: 32,000), ULTEM1040 (average molecular weight: 20,000) (trade name, manufactured by SABIC Innovative Plastics Co., Ltd.), etc. However, it is not limited to these.

As block polymers, Nanostrength M52, Nanostrength M52N, Nanostrength M22, Nanostrength M22N, Nanostrength 123, Nanostrength 250, Nanostrength 250, Nanostrength 250, Nanostrength 012, Nanostrength 012, Nanostrength 012, Nanostrength Examples thereof include, but are not limited to, TPAE-12, TPAE-23, TPAE-31, TPAE-38, TPAE-63, TPAE-100, PA-260 (all trade names, manufactured by T & K TOKA).

One of these thermoplastic resins may be used alone, or two or more thereof may be used in combination.

When the epoxy resin composition of the present invention contains a thermoplastic resin other than the epoxy resin, the content thereof is 15 parts by mass or less with respect to 100 parts by mass of the epoxy resin of the present invention in the epoxy resin composition of the present invention. Preferably, 10 parts by mass or less is more preferable. When the content of the thermoplastic resin is 15 parts by mass or less, the effect of controlling the resin flow and improving the physical properties tends to be satisfactorily exhibited while maintaining the impact resistance.

<Arbitrary ingredient>
If necessary, the epoxy resin composition of the present invention may contain various known additives as long as the effects of the present invention are not impaired, thereby improving the storage stability of the composition and discoloring the cured product. Antioxidants and light stabilizers can also be added to avoid deterioration.

Specific examples of this include, for example, various commercially available Sumitomo Chemical Co., Ltd. Sumilyzer BHT, Sumilyzer S, Sumilyzer BP-76, Sumilyzer MDP-S, Sumilyzer GM, Sumilyzer BBM-S, Sumilyzer WX-R, Sumilyzer. NW, Sumilyzer BP-179, Sumilyzer BP-101, Sumilyzer GA-80, Sumilyzer TNP, Sumilyzer TPP-R, Sumilyzer P-16; Asahi Denka Kogyo Co., Ltd. Adekastab AO-20, Adekastab AO-30, Adekastab AO- 40, Adekastab AO-50, Adekastab AO-60AO-70, Adekastab AO-80, Adekastab AO-330, Adekastab PEP-4C, Adekastab PEP-8, Adekastab PEP-24G, Adekastab PEP-36, Adekastab HP-10, Adekastab 2112, Adekastab 260, Adekastab 522A, Adekastab 329K, Adekastab 1500, Adekastab C, Adekastab 135A, Adekastab 3010; Ciba Speciality Chemicals Co., Ltd. Chinubi 770, Chinubin 765, Chinubin 144, Chinubin 622 292; Funkrill FA-711M, FA-712HM, etc. manufactured by Hitachi Kasei Kogyo Co., Ltd. can be mentioned.

When these antioxidants and light stabilizers are contained in the epoxy resin composition of the present invention, the amount thereof added is not particularly limited, but it may be added to 100 parts by mass of the epoxy resin of the present invention in the epoxy resin composition of the present invention. On the other hand, the range is preferably 0.001 to 20 parts by mass, and more preferably 0.01 to 15 parts by mass.

Other additives include thermosetting elastomers, thermoplastic elastomers, flame retardants (for example, phosphorus-containing epoxy resins, red phosphorus, phosphazene compounds, phosphates, phosphate esters, etc.), silicone oils, wet dispersants, and defoamers. Agents, defoaming agents, natural waxes, synthetic waxes, metal salts of linear fatty acids, acid amides, esters, mold release agents such as paraffins, crystalline silica, molten silica, calcium silicate, alumina, calcium carbonate. , Powders such as talc and barium sulfate, metal oxides, metal hydroxides, glass fibers, carbon nanotubes, inorganic fillers such as fullerene, organic fillers such as carbon fibers and cellulose nanofibers, inorganic fillers with surface organic treatment, etc. , Carbon black, colorants such as red iron oxide, silane coupling agents, conductive materials and other known additives. Further, if necessary, a slip agent, a leveling agent, a polymerization inhibitor such as hydroquinone monomethyl ether, an ultraviolet absorber and the like can be blended.
These may be used individually by 1 type, and may be used in combination of 2 or more type.

<Manufacturing method of epoxy resin composition>
The epoxy resin composition of the present invention is not limited to the following, but can be obtained, for example, by mixing the above-mentioned components.
Examples of the mixing method of each component include a method using a mixer such as a three-roll mill, a planetary mixer, a kneader, a homogenizer, and a homodisper.

<Reinforcing fiber>
The reinforcing fiber is not particularly limited, and a known reinforcing fiber constituting the fiber-reinforced composite material may be appropriately selected depending on the application and the like. As specific examples of the reinforcing fibers, various inorganic fibers or organic fibers such as carbon fibers, aramid fibers, nylon fibers, high-strength polyester fibers, glass fibers, boron fibers, alumina fibers, and silicon nitride fibers can be used. Among these, carbon fiber, aramid fiber, glass fiber, boron fiber, alumina fiber, and silicon nitride fiber are preferable from the viewpoint of specific strength and specific elasticity, and carbon is preferable from the viewpoint of mechanical properties, heat resistance, electromagnetic wave shielding property, and light weight. Fiber is particularly preferred. When carbon fiber is used as the reinforcing fiber, the surface treatment with metal may be applied.
One type of these reinforcing fibers may be used alone, or two or more types may be used in combination.

From the viewpoint of the rigidity of the fiber-reinforced plastic obtained by using the fiber-reinforced epoxy resin composite material of the present invention, the tensile strength of the carbon fiber strand used as the reinforcing fiber is preferably 1 to 9 GPa, more preferably 1.5 to 9 GPa. The tensile elastic modulus is preferably 150 to 1,000 GPa, more preferably 200 to 1,000 GPa.
Here, the tensile strength and the tensile elastic modulus of the carbon fiber strand are values measured in accordance with JIS R 7601: 1986.

The form of the reinforcing fiber is not particularly limited, and a form used as a base material of a normal fiber-reinforced composite material can be adopted. For example, the reinforcing fiber may be aligned in one direction, and may be a woven fabric or a fabric. It may be a non-woven fabric or a non-crimp fabric (NCF).

The basis weight of the carbon fiber aggregate used as the reinforcing fiber is not particularly limited, but is preferably about 30 to 1000 g / m ² , and particularly preferably about 50 to 800 g / m ² . When the basis weight of the carbon fiber aggregate is at least the above lower limit, the number of laminations can be appropriately maintained, and when it is at least the above upper limit, the epoxy resin composition is easily impregnated and the drape property can be maintained.

<Manufacturing method of fiber reinforced epoxy resin composite material>
The fiber-reinforced epoxy resin composite material of the present invention can be produced by impregnating a reinforcing fiber, preferably an aggregate of reinforcing fibers, with the epoxy resin composition of the present invention.

Generally, as a method of impregnating a reinforcing fiber aggregate with an epoxy resin, for example, a wet method of impregnating a low-viscosity epoxy resin composition having a relatively large solvent content and a method of impregnating the epoxy resin composition with a low viscosity by heating. Known methods such as a hot melt method (dry method) for impregnating with an epoxy resin are known, but in the present invention, an epoxy resin composition containing an epoxy resin and a solvent is impregnated into a reinforcing fiber by a hot melt method. The hot melt method includes a method of directly impregnating the reinforcing fibers with a resin composition whose viscosity has been reduced by heating, and a method of once coating the resin composition on a release paper or the like to prepare a film, and then applying this film. There is a method of impregnating the reinforcing fibers with an epoxy resin by superimposing them on both sides or one side of an aggregate of reinforcing fibers and heating and pressurizing them.

The fiber-reinforced epoxy resin composite material of the present invention is preferably produced by using the above-mentioned film even in the hot melt method. According to this method, unlike the wet method, the residual solvent in the fiber-reinforced epoxy resin composite material can be remarkably reduced, and the fiber-reinforced epoxy resin having an extremely low solvent content while impregnating the reinforcing fibers with the epoxy resin. It can be used as a composite material, and by using this fiber-reinforced epoxy resin composite material, a fiber-reinforced plastic having extremely few voids and excellent mechanical properties can be obtained.

<Solvent content of fiber reinforced epoxy resin composite material>
The solvent content of the fiber-reinforced epoxy resin composite material of the present invention is 0.02% by mass or more and 5% by mass or less, preferably 0.05, when the total mass of the fiber-reinforced epoxy resin composite material is 100% by mass. It is mass% or more and 4 mass% or less. When the solvent content in the fiber-reinforced epoxy resin composite material exceeds 5% by mass, voids are generated in the fiber-reinforced plastic obtained by using this fiber-reinforced epoxy resin composite material due to this residual solvent, and the voids are generated. However, since it becomes the starting point of fracture when stress is concentrated, it is not possible to obtain a fiber reinforced plastic having excellent mechanical properties. The smaller the solvent content of the fiber-reinforced epoxy resin composite material of the present invention is, the more preferable it is, but when it is 0.02% by mass or more, impregnation is easy.
The solvent content in the fiber-reinforced epoxy resin composite material can be determined by heating in an oven at 200 ° C. for 1.5 hours to volatilize the solvent and measuring the weight. The solvent content was also determined by this method in the examples described later.

<Resin and reinforcing fiber content of fiber reinforced epoxy resin composite material>
The resin content (content of the resin component including the epoxy resin) of the fiber-reinforced epoxy resin composite material of the present invention is 15 to 50% by mass when the total mass of the fiber-reinforced epoxy resin composite material is 100% by mass. It is preferably 20 to 45% by mass, more preferably 25 to 40% by mass. When the resin content is 15% by mass or more, sufficient adhesiveness between the reinforcing fiber and the resin component such as epoxy resin can be sufficiently secured, and when it is 50% by mass or less, the mechanical properties tend to be kept high. ..

[Epoxy resin film]
The epoxy resin film of the present invention is a film composed of an epoxy resin composition containing an epoxy resin and a solvent, and is characterized in that the solvent content in the film is 0.2% by mass or more and 10% by mass or less.

The epoxy resin film of the present invention is used as an intermediate material for producing the fiber-reinforced epoxy resin composite material of the present invention by superimposing it on an aggregate of reinforcing fibers by the above-mentioned hot melt method and heating and pressurizing the fiber. It is suitably used as a film for producing an epoxy resin composite material.
That is, the fiber-reinforced epoxy resin composite material of the present invention can be produced by attaching the epoxy resin film of the present invention to a reinforcing fiber base material, impregnating it with a resin, and curing it with a curing agent in some cases. The epoxy resin film of the present invention is also useful as a surface protective film or an adhesive film.

The method for producing the epoxy resin film of the present invention is not particularly limited, but a method of applying the epoxy resin composition of the present invention to the surface of a base material such as a PET film or a release paper to form a film is preferable. Examples of the film forming method include roll coating, reverse coating, comma coating, knife coating, die coating, gravure coating, melt extrusion method, solution casting method, T die method, calendar method and the like. By using the coextrusion method or the laminating method, it is possible to increase the thickness or to laminate products having different resin compositions.

In this way, when the epoxy resin film of the present invention is produced, the drying and / or curing reaction of the epoxy resin composition of the present invention may proceed to such an extent that the shape can be maintained by heating or the like. When the epoxy resin composition contains a solvent, most of the solvent is removed by a method such as heating, depressurizing, or air-drying to make the entire epoxy resin film 100% by mass in the epoxy resin film. The solvent is removed so that the solvent content is 0.2% by mass or more and 10% by mass or less, particularly 0.4% by mass or more and 8% by mass or less. When the solvent content of the epoxy resin film exceeds 10% by mass, the solvent content of the obtained fiber-reinforced epoxy resin composite material exceeds 5% by mass, and a fiber-reinforced plastic having few voids and excellent mechanical properties is produced. You will not be able to get it. The smaller the solvent content of the epoxy resin film of the present invention is, the more preferable it is, but if it is less than 0.2% by mass, the epoxy resin composition is less likely to be impregnated.
The solvent content of the epoxy resin film can be determined in the same manner as the solvent content of the fiber-reinforced epoxy resin composite material.

The thickness of the epoxy resin film of the present invention is not particularly limited, but is preferably 10 μm or more and 500 μm or less, more preferably 20 μm or more and 400 μm or less, and particularly preferably 30 μm or more and 300 μm or less. If the thickness of the epoxy resin film is at least the above lower limit, the film can be produced without the resin being repelled, and if it is at least the above upper limit, the form of the film can be maintained during film production, which is preferable.

If necessary, the epoxy resin film of the present invention can be imparted with new functions by physical surface treatment, chemical surface treatment, coating, or the like.
it can.

In order to produce the fiber-reinforced epoxy resin composite material of the present invention using the epoxy resin film of the present invention, for example, the epoxy resin film of the present invention is laminated on one or both surfaces of an aggregate of reinforcing fibers, and 80 Examples thereof include a method of integrating the epoxy resin film and the reinforcing fiber by heating at about 200 ° C. At the time of this heating, pressure may be applied at about 0.5 to 10 MPa, or vacuuming may be performed to promote impregnation of the resin.

[Fiber reinforced plastic]
The fiber reinforced plastic of the present invention is produced by using the fiber reinforced epoxy resin composite material of the present invention. The fiber reinforced plastic of the present invention can be produced according to a general method for producing a fiber reinforced plastic using a prepreg, except that the fiber reinforced epoxy resin composite material of the present invention is used as a prepreg.
That is, for example, after laminating the fiber-reinforced epoxy resin composite material of the present invention, there is a method of molding by heating and curing the epoxy resin while applying pressure to the laminate. When laminating the prepreg, the fiber-reinforced epoxy resin composite material of the present invention may be combined with a fiber-reinforced sheet impregnated with another thermoplastic resin.

When cured as the fiber-reinforced plastic of the present invention, it varies depending on the compounding components and the compounding amount in the epoxy resin composition used for producing the fiber-reinforced epoxy resin composite material and the shape of the compound, but at, for example, 23 to 250 ° C. It takes 5 minutes to 24 hours.

Examples of the molding method of the fiber reinforced plastic of the present invention include a press molding method, an autoclave molding method, a bagging molding method, a lapping tape method, an internal pressure molding method, a sheet wrap molding method, and the like, but are limited to these molding methods. is not.

The wrapping tape method is a method of winding a prepreg around a core metal such as a mandrel to form a tubular body made of fiber reinforced plastic, and is preferably used when producing a rod-shaped body such as a golf shaft or a fishing rod. More specifically, the prepreg is wound around the mandrel, a wrapping tape made of a thermoplastic film is wound on the outside of the prepreg to fix the prepreg, and the resin is heat-cured in an oven, and then the core metal is used. It is a method of obtaining a fiber-reinforced plastic tubular body by extracting.

In the internal pressure molding method, a preform in which a prepreg is wound around an internal pressure applying body such as a tube made of a thermoplastic resin is set in a mold, and then a high pressure gas is introduced into the internal pressure applying body to apply pressure and at the same time gold. This is a method of heating a mold and molding it. This method is preferably used when molding a complicated shape such as a golf shaft, a bat, a racket such as tennis or badminton.

The fiber reinforced plastic of the present invention is suitably used for sports applications, general industrial applications, and aerospace applications. More specifically, in sports applications, it is suitably used for golf shafts, fishing rods, rackets for tennis and badminton, stick applications such as hockey, and ski pole applications. Furthermore, in general industrial applications, structural materials for moving bodies such as automobiles, ships, and railroad vehicles, drive shafts, leaf springs, wind turbine blades, pressure vessels, flywheels, papermaking rollers, roofing materials, cables, repair reinforcement materials, etc. Suitable for use.

[Structure]
The structure can be obtained from the fiber reinforced plastic of the present invention. This structure may consist only of the fiber reinforced plastic of the present invention, or may be composed of the fiber reinforced plastic of the present invention and other materials (for example, metal, injection-molded thermoplastic resin member, etc.). It may be what is done.
Since this structure is partially or wholly composed of fiber reinforced plastic made of the fiber reinforced epoxy resin composite material of the present invention, it is excellent in flame retardancy and heat resistance, and also excellent in mechanical properties.
In addition to the above-mentioned applications of the fiber-reinforced plastic of the present invention, this structure can also be applied to, for example, interior members of aircraft and automobiles, housings for electric and electronic devices, and the like.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to the following Examples as long as the gist of the present invention is not exceeded.

[material]
The raw materials used in the following examples, comparative examples and reference examples are as follows.

<Epoxy resin>
jER1256: Solid bisphenol A type epoxy resin, Mw: about 50,000, epoxy equivalent: about 8,000 g / eq, manufactured by Mitsubishi Chemical Co., Ltd. jER1055: Solid bisphenol A type epoxy resin, Mw: about 1,600, epoxy equivalent: Approximately 850 g / eq, manufactured by Mitsubishi Chemical Co., Ltd. jER1003: Solid bisphenol A type epoxy resin, Mw: Approximately 1,300, epoxy equivalent: Approximately 720 g / eq, manufactured by Mitsubishi Chemical Co., Ltd.

<Solvent>
Methyl ethyl ketone

<Reinforcing fiber>
Pyrofil TR3110M: carbon fiber cloth, fiber basis weight: 200 g / m ² , manufactured by Mitsubishi Chemical Corporation

[Example 1]
Using jER1256 as the epoxy resin and methyl ethyl ketone as the solvent, an epoxy resin composition was prepared as follows.
First, the epoxy resin (solid) and the solvent (liquid) were weighed in a container so that the solid concentration was 40% by mass, mixed and dissolved to obtain a 40% by mass methyl ethyl ketone solution of jER1256.
This solution was applied onto a silicone-treated PET film using a slot die coating device (manufactured by Yasui Seiki Co., Ltd.) at a coating speed of 2.0 m / min, dried at a drying temperature of 150 ° C. for 6 minutes, and thickened. A 50 μm jER1256 epoxy resin film was obtained. 2.1% by mass of the solvent remained in this epoxy resin film (solvent content 2.1% by mass).
This epoxy resin film is laminated on both sides of a carbon fiber cloth (Pyrofil TR3110M) and impregnated while vacuuming with a press machine set to 160 ° C. in advance to obtain a fiber-reinforced epoxy resin composite material having a resin content of 37.3% by mass. Prepreg) was obtained. The solvent content in this prepreg was 0.7% by mass.

[Example 2]
A prepreg was prepared in the same manner as in Example 1 except that jER1055 was used as the epoxy resin.

[Comparative Example 1]
Using jER1256 as the epoxy resin and methyl ethyl ketone as the solvent, an epoxy resin composition was prepared as follows.
First, the epoxy resin (solid) and the solvent (liquid) were weighed in a container so that the solid concentration was 20% by mass, mixed and dissolved to obtain a 20% by mass methyl ethyl ketone solution of jER1256.
Subsequently, a carbon fiber cloth (pyrofilm TR3110M) was cut to a length of 20 mm and a width of 130 mm, and 1.55 g of the obtained solution was applied and impregnated there, and then at 60 ° C. for 20 minutes, 150. The solvent was removed by drying at ° C. for 20 minutes. Then, it was impregnated at 150 kN at 160 ° C. for 30 minutes while evacuating with a press to obtain a prepreg having a resin content of 37.3% by mass. The solvent content in the obtained prepreg was 0.4% by mass.

[Reference example 1]
A prepreg was prepared in the same manner as in Example 1 except that jER1003 was used as the epoxy resin.

The prepared prepreg was evaluated as follows. The results are shown in Table 1.

[Evaluation of prepreg void number]
With respect to the obtained prepreg, the number of voids present in a 5 mm square was observed with an optical microscope, and less than 100 voids per observation area were marked with ◯, and 100 or more per unit area was marked with x. When the number of voids is less than 100 per area, the voids disappear by molding while vacuuming with a press machine at the time of producing the reinforcing fiber plastic, and the reinforcing fiber plastic having excellent mechanical properties can be obtained. When the number of voids is 100 or more per the area, the voids cannot be completely removed even if the reinforcing fiber plastic is formed while being evacuated at the time of manufacturing, resulting in a reinforcing fiber plastic having low mechanical properties.

[Evaluation of prepreg peelability]
Two of the obtained prepregs were laminated, and the load was 58 g / cm ² at 55 ° C. for 30 minutes. Then, it was confirmed whether or not the prepregs were peeled off. The thing is x.
Those from which the prepregs are peeled off are preferable because the prepregs do not adhere to each other when they are mistakenly laminated and heated. Those in which the prepregs do not peel off are not preferable because the prepregs adhere to each other when they are mistakenly laminated and heated.

As shown in Table 1, in Example 1 by the hot melt method, prepreg without voids and fiber reinforced plastic were obtained in spite of the large amount of solvent in the prepreg, as compared with Comparative Example 1 by the wet method in which voids were generated. Was done. Further, Example 2 was peeled off, but Reference Example 1 was not peeled off. In Reference Example 1, the prepreg was fused because the weight average molecular weight of the epoxy resin used was low.

By using the fiber-reinforced epoxy resin composite material of the present invention, it is possible to obtain a fiber-reinforced plastic having extremely few voids and excellent mechanical properties. Therefore, according to the present invention, it is possible to provide a wide range of fiber-reinforced plastic molded articles having excellent mechanical properties, from molded articles for sports / leisure applications such as shafts for golf clubs to molded articles for industrial applications such as aircraft.

Claims (12)

A fiber-reinforced epoxy resin composite material obtained by impregnating reinforcing fibers with an epoxy resin composition containing an epoxy resin and a solvent by a hot melt method and having a solvent content of 0.02% by mass or more and 5% by mass or less. The fiber-reinforced epoxy resin composite material according to claim 1, wherein the epoxy resin is an epoxy resin having a weight average molecular weight of 1500 or more. The epoxy resin is a mixture of an epoxy resin having a weight average molecular weight of 1500 or more and an epoxy resin having a weight average molecular weight of less than 1500, and the ratio of the epoxy resin having a weight average molecular weight of 1500 or more to 100 parts by mass of the total epoxy resin is 60 parts by mass or more. The fiber-reinforced epoxy resin composite material according to claim 1. The fiber-reinforced epoxy resin composite material according to any one of claims 1 to 3, wherein the reinforcing fiber is carbon fiber. A fiber reinforced plastic using the fiber reinforced epoxy resin composite material according to any one of claims 1 to 4. An epoxy resin film comprising an epoxy resin composition containing an epoxy resin and a solvent, wherein the solvent content in the film is 0.2% by mass or more and 10% by mass or less. The epoxy resin film according to claim 6, wherein the epoxy resin is an epoxy resin having a weight average molecular weight of 1500 or more. The epoxy resin is a mixture of an epoxy resin having a weight average molecular weight of 1500 or more and an epoxy resin having a weight average molecular weight of less than 1500, and the ratio of the epoxy resin having a weight average molecular weight of 1500 or more to 100 parts by mass of the total epoxy resin is 60 parts by mass or more. The epoxy resin film according to claim 6. A fiber-reinforced epoxy resin composite material obtained by heating and integrating a laminate of the epoxy resin film according to any one of claims 6 to 8 and a reinforcing fiber aggregate. A method for producing a fiber-reinforced epoxy resin composite material having a reinforcing fiber and an epoxy resin composition.
(A) An epoxy resin composition containing an epoxy resin and a solvent is prepared.
(B) The temperature of the prepared epoxy resin composition was adjusted in the range of 20 to 70 ° C. to form a coating film.
(C) The coating film was held at a temperature of 80 to 180 ° C. for 5 minutes to 3 hours to volatilize the solvent to prepare a resin film.
(D) The resin film is heat-bonded to the reinforcing fibers to impregnate the epoxy resin composition to produce a fiber-reinforced epoxy resin composite material having a solvent content of 0.02% by mass or more and 5% by mass or less. A method for manufacturing a fiber-reinforced epoxy resin composite material. The method for producing a fiber-reinforced epoxy resin composite material according to claim 10, wherein the epoxy resin is an epoxy resin having a weight average molecular weight of 1500 or more. The epoxy resin is a mixture of an epoxy resin having a weight average molecular weight of 1500 or more and an epoxy resin having a weight average molecular weight of less than 1500, and the ratio of the epoxy resin having a weight average molecular weight of 1500 or more to 100 parts by mass of the total epoxy resin is 60 parts by mass or more. The method for producing a fiber-reinforced epoxy resin composite material according to claim 10.