JP2019189750A - Epoxy resin composition, prepreg containing epoxy resin composition, and cured article thereof - Google Patents

Abstract

To provide an epoxy resin composition which completes curing in a short time even at a low temperature and can provide, by being used as a matrix resin of a prepreg, a fiber reinforced composite resin molded body having excellent mechanical physical property, especially excellent break strain and heat resistance.SOLUTION: There is provided an epoxy resin composition containing the following component (A), component (B), component (C) and component (D). Component (A): a reaction product of an epoxy resin and an amine compound having at least one sulfur atom in a molecule, and/or an epoxy resin having at least one sulfur atom in a molecule. Component (B): a novolac type epoxy resin. Component (C): an epoxy resin having a bisphenol skeleton structure and a linear hydrocarbon structure having 6 or more carbon atoms, and/or an epoxy resin having a bisphenol skeleton and a polypropylene glycol skeleton structure having 4 or more ether oxygen atom number. Component (D): a curing agent.SELECTED DRAWING: None

Description

  The present invention relates to a fiber reinforced composite resin molded article used for sports / leisure applications, industrial applications, and the like, an epoxy resin composition suitably used for a fiber reinforced composite resin molded article, a prepreg using the same, and a prepreg It is related with the hardened | cured material of the laminated body in which 2 or more of these were laminated | stacked.

  Fiber reinforced composite resin moldings, which are one of fiber reinforced composite materials, are widely used for sports and leisure applications, and industrial applications such as automobiles and aircraft, because of their light weight, high strength, and high rigidity. . Among fiber reinforced composite resin moldings, fiber reinforced composite resin tubular bodies are frequently used for sports and leisure applications such as fishing rods, golf club shafts, ski poles, bicycle frames, and the like.

  As a method for producing a fiber-reinforced composite resin molded body, there is a method of using an intermediate material obtained by impregnating a matrix resin into a reinforcing material made of long fibers such as reinforcing fibers, that is, a prepreg. According to this method, there is an advantage that the content of the reinforcing fiber in the fiber-reinforced composite resin molded body can be easily managed and the content can be designed to be higher.

  As a resin composition used for this prepreg, an epoxy resin composition excellent in mechanical properties, heat resistance and handleability is widely used. Epoxy resin compositions used for sports / leisure use, industrial use, and the like are required to satisfy both breaking strain and heat resistance. In order to improve the breaking strain of the epoxy resin composition, it is also effective to lower the crosslinking density of the epoxy resin composition. However, by reducing the crosslinking density, the heat resistance of the cured product tends to be lowered. For this reason, it has been a very difficult task to achieve both the fracture strain and the heat resistance of the composite material.

Specific methods for obtaining fiber reinforced plastic from prepreg include, for example, a molding method using an autoclave, press molding, internal pressure molding, oven molding, and the like. In any of these methods, when the prepreg is laminated, formed into the desired mold, and then heat-cured, it takes about 2 to 6 hours under the condition of about 160 ° C. or higher before curing. . That is, treatment at a high temperature and for a long time was required (see JP-A-10-128778).
On the other hand, in order to improve the molding cycle, it is required that molding can be performed in a short time of several minutes to several tens of minutes at a relatively low temperature of about 100 to 140 ° C. Therefore, in order to avoid undesired deformation when the fiber reinforced composite material is taken out from the mold, the glass transition temperature of the fiber reinforced composite material after curing, in particular, G′-Tg, which is determined as the temperature at which the storage rigidity starts to decrease. However, it is desirable that the temperature is higher than the mold temperature during molding. That is, it is preferable that G′-Tg of the cured product of the epoxy resin composition is 145 ° C. or higher.

  Against this background, when it is cured in a short time even at low temperatures, and when used as a matrix resin for prepreg, it is a fiber reinforced composite with excellent mechanical properties, especially excellent fracture strain and heat resistance. There is a demand for an epoxy resin composition capable of producing a resin molded body.

  As a prepreg excellent in mechanical properties and breaking strain of an epoxy resin composition, Patent Document 1 discloses an epoxy resin composition using dicyandiamide as a latent curing agent excellent in breaking strain and polyvinyl formal as a thermoplastic resin elastomer. A prepreg having a matrix resin as a product is shown.

  As prepregs that can be molded at a relatively low temperature and in a short time, Patent Document 2 and Patent Document 3 used an epoxy resin composition containing a reaction product of an amine compound containing a sulfur atom in the molecule and an epoxy resin. A prepreg is shown.

Patent No. 6079943 International Publication 2014/030636 Japanese Patent Laid-Open No. 13-159696

  However, the technique of Patent Document 1 requires a curing time of 2 hours at 180 ° C., and does not meet the above-described requirements.

  In addition, the techniques of Patent Documents 2 and 3 have sufficient curability, but the fracture strain and heat resistance are not sufficient.

  The present invention has been made in view of the above background, and can be cured in a short time even at a low temperature, and can be used as a matrix resin for a prepreg to provide excellent mechanical properties, particularly excellent break strain and heat resistance. It is an object of the present invention to provide an epoxy resin composition capable of obtaining a fiber-reinforced composite resin molding, a prepreg using the same, and a cured product of a laminate in which two or more prepregs are laminated.

  In order to solve the above-mentioned problems, the present inventors have intensively studied, and as a result, have reached the following present invention.

Reinforcing fibers are impregnated with a poxy resin composition containing the following component (A), component (B), component (C) and component (D).
Component (A): reaction product of epoxy resin and amine compound having at least one sulfur atom in the molecule, and / or epoxy resin having at least one sulfur atom in the molecule Component (B): novolac type epoxy resin Component (C): an epoxy resin having a bisphenol skeleton structure and a linear hydrocarbon structure having 6 or more carbon atoms, and / or a polypropylene glycol skeleton structure having a bisphenol skeleton structure and 4 or more ether oxygen atoms Epoxy resin Component (D): Curing agent

  The present invention has been made in view of the above background, and can be cured in a short time even at a low temperature, and can be used as a matrix resin for a prepreg to provide excellent mechanical properties, particularly excellent break strain and heat resistance. The epoxy resin composition which can obtain the provided fiber reinforced composite resin molding, the prepreg using the same, and the hardened | cured material of the laminated body on which 2 or more of prepregs were laminated | stacked can be provided.

  The best mode for carrying out the invention will be described below.

<Component (A)>
Component (A) is a reaction product of an epoxy resin and an amine compound having at least one sulfur atom in the molecule, and / or an epoxy resin having at least one sulfur atom in the molecule. Moreover, the epoxy resin containing following formula (1) or formula (2) can also be used, and the reaction product of an epoxy resin and the amine compound which has at least 1 sulfur atom in a molecule | numerator can also be used. By using the component (A), curing at a low temperature and in a short time becomes possible. In one embodiment of the present invention, “low temperature” means a temperature of 100 to 140 ° C. Further, “short time” means 10 to 30 minutes.

Formula (1)

Formula (2)
(In the formula (2), R is —SO _2. )

  The amine compound having at least one sulfur atom in the molecule is not particularly limited, and examples thereof include 4,4′-diaminodiphenylsulfone, 3,3′-diaminodiphenylsulfone, 4,4′-diaminodiphenylsulfide, Bis (4- (4aminophenoxy) phenyl) sulfone, bis (4- (3aminophenoxy) phenyl) sulfone, 4′4-diaminodiphenylsulfide, o-trianesulfone, and derivatives thereof are preferably used. .

  The epoxy resin composition containing the component (A) of the present invention can also be obtained by mixing an epoxy resin and an amine compound having at least one sulfur atom in the molecule and reacting them, thereby obtaining a mixture containing the component (A). It is not particularly necessary to isolate and use component (A) from the above. It is more preferable to use a reaction product of the component (A) and an amine compound having at least one sulfur atom in the molecule because the viscosity adjustment of the epoxy resin composition is facilitated.

  Examples of the epoxy resin having a sulfur atom in the molecule include a bisphenol S-type epoxy resin and an epoxy resin having a thio skeleton, and these can also be used in the present invention. However, in order to use these effectively in this invention, it is necessary to quantify the content rate of the sulfur atom in an epoxy resin composition. An atomic absorption method or the like may be used as a method for previously quantifying the sulfur atom content in the epoxy resin composition.

  Commercial products of amine compounds having at least one sulfur atom in the molecule include “YSLV-120TE” and “YSLV-50TE” (manufactured by Nippon Steel Chemical Co., Ltd.), “Epicron EXA-1514” and “Epicron EXA- 1517 "(manufactured by DIC Corporation).

  The component (A) contained in the epoxy resin composition in the present invention can be cured at a low temperature and in a short time, and 3 to 50 masses with respect to 100 mass parts of the total epoxy resin composition from the viewpoint of maintaining physical properties. Part.

<Component (B)>
Component (B) is a novolac type epoxy resin. By using the component (B), the heat resistance of the epoxy resin composition can be maintained.

  Examples of commercially available components (B) include phenol novolac type epoxy resins such as “jER152” and “jER154” (manufactured by Mitsubishi Chemical Corporation), “Epicron 740” and “Epicron 775” (manufactured by DIC Corporation). The cresol novolak type epoxy resin is a commercially available product of cresol novolak type epoxy resin, such as “Epiclon” (registered trademark) N-660, N-665 (manufactured by DIC Corporation), EOCN-1020, EOCN-102S. (Nippon Kayaku Co., Ltd.), YDCN-700, YDCN-701 (Nippon Steel Chemical Co., Ltd.), etc. are mentioned. Two or more of these epoxy resins may be used in combination.

<Ingredient (C)>
Component (C) comprises an epoxy resin having a bisphenol skeleton structure and a linear hydrocarbon structure having 6 or more carbon atoms, and / or a polypropylene glycol skeleton structure having a bisphenol skeleton structure and having 4 or more ether oxygen atoms. It is an epoxy resin. By using the component (C), fracture strain can be expressed in the cured epoxy resin while maintaining a high glass transition temperature.

  As a commercial item of a component (C), "Epiclon EXA-4816", "Epiclon EXA-4850" (made by DIC Corporation), etc. are mentioned.

  The component (C) contained in the epoxy resin composition in the invention is 5 to 20 parts by mass with respect to 100 parts by mass of the total epoxy resin composition from the viewpoint of improving fracture strain while maintaining heat resistance. Is preferred.

<Component (D)>
Component (D) is a curing agent. Examples of the curing agent include amines, acid anhydrides (such as carboxylic acid anhydrides), phenols (such as novolak resins), mercaptans, Lewis acid amine complexes, onium salts, imidazoles, and the like, which can cure epoxy resins. Any structure can be used. Among these, amine type curing agents are preferable. These curing agents may be used alone or in combination of two or more. Examples of amine-type curing agents include aromatic amines such as diaminodiphenylmethane and diaminodiphenylsulfone, aliphatic amines, imidazole derivatives, dicyandiamide, tetramethylguanidine, thiourea-added amines, and isomers and modified forms thereof. . Among these, dicyandiamide is particularly preferable in terms of excellent prepreg storage.

  As a commercial item of a component (D), "DICYANEX1400F (above, Evonik Japan make)" jER cure (trademark) "DICY7 and jER cure DICY15 (above, Mitsubishi Chemical Corporation make) etc. are mentioned, for example.

  It is preferable that the component (D) contained in the epoxy resin composition in the present invention is 2 to 15 parts by mass with respect to 100 parts by mass of the total epoxy resin composition. If the content of the component (D) is 2 parts by mass, the curing reaction proceeds sufficiently, and if it is 15 parts or less, sufficient storage stability is obtained, and the physical properties of the cured resin are also good.

<Ingredient (E)>
Component (E) is a urea compound. Component (E) may be used to increase the curing activity. For example, when the curing agent is dicyandiamide, the curing aid is 3-phenyl-1,1-dimethylurea, 3- (3,4-dichlorophenyl) -1,1-dimethylurea (DCMU), 3- (3-chloro Urea derivatives such as -4-methylphenyl) -1,1-dimethylurea, 2,4-bis (3,3-dimethylureido) toluene, phenyldimethylurea (PDMU) are preferred. Among these, a combination of dicyandiamide and PDMU is particularly preferable in terms of curing at a low temperature for a short time.

  A commercial item can be used as a component (E). For example, 2,4-bis (3,3-dimethylureido) toluene (TBDMU) includes “Omicure (registered trademark)” 24 (manufactured by PTI Japan) and phenyldimethylurea (PDMU). ) Includes Omicure 94 (manufactured by PTI Japan Co., Ltd.) and the like, and 4,4′-methylenebis (phenyldimethylurea) (MDMU) is Omicure 52 and Omicure 54 (above, PTI Corporation). I Japan Co., Ltd.) and the like, and 3- (3,4-dichlorophenyl) -1,1-dimethylurea includes DCMU99 (Hodogaya Chemical Co., Ltd.) and the like.

  It is preferable that the component (E) contained in the epoxy resin composition in the invention is 1 to 10 parts by mass with respect to 100 parts by mass of the total epoxy resin composition. If the content of the component (E) is 1 part by mass, a curing promoting function is obtained, and if it is 10 parts by mass or less, storage stability at 20 ° C. is obtained.

<Other epoxy resins>
Examples of other epoxy resins that can be used in the epoxy resin composition of the present invention include bisphenol A type epoxy resins, bisphenol F type epoxy resins, and epoxy resins obtained by modifying these as bifunctional epoxy resins. Two or more of these epoxy resins may be used in combination. Examples of the trifunctional or higher polyfunctional epoxy resins include novolak type epoxy resins, naphthalene type epoxy resins, glycidylamine type epoxy resins, and epoxy resins obtained by modifying these epoxy resins. There is no limitation. Two or more of these epoxy resins may be used in combination.

  As a commercial product of a bifunctional epoxy resin, as a commercial product of a bisphenol A type epoxy resin, for example, “jER (registered trademark)” 825, jER826, jER827, jER828, jER834 and jER1001 (above, manufactured by Mitsubishi Chemical Corporation), “Epicron (registered trademark)” 850 (manufactured by DIC Corporation), “Epototo (registered trademark)” YD-128 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), “DER (registered trademark)”-331 and DER-332 ( As described above, Dow Chemical Japan Co., Ltd.), “Bakelite (registered trademark)” EPR154, Bakelite EPR162, Bakelite EPR172, Bakelite EPR173, and Bakelite EPR174 (above, made by Bakelite AG) are listed. Examples of commercially available products of bisphenol F type epoxy resin include jER806, jER807 and jER1750 (manufactured by Mitsubishi Chemical Corporation), Epicron 830 (manufactured by DIC Corporation), Epototo YD-170 and Epototo YD-175 (and above). , Manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), Bakelite EPR169 (manufactured by Bakelite AG), GY281, GY282 and GY285 (manufactured by Huntsman Advanced Material).

  Examples of commercially available polyfunctional epoxy resins include novolak type epoxy resins such as N695 (manufactured by DIC Corporation), and naphthalene type epoxy resins such as HP-4032 and HP-4700 (manufactured by DIC Corporation), NC- 7300 (manufactured by Nippon Kayaku Co., Ltd.) and the like, and jER630 (manufactured by Mitsubishi Chemical Corporation), Araldite MY0500, Araldite MY0510, Araldite MY0600 (above, manufactured by Huntsman Advanced Materials), and the like.

  A prepreg can be obtained by impregnating the fiber reinforcing material with the epoxy resin composition of the present invention. The fiber reinforcing material that can be used in the prepreg of the present invention is not limited, and carbon fiber, graphite fiber, glass fiber, organic fiber, boron fiber, steel fiber, etc., in the form of tow, cloth, chopped fiber, mat, etc. Can be used. Among these, carbon fiber and graphite fiber can be suitably used for the prepreg of the present invention because they have good specific elastic modulus and a large effect on weight reduction. Also, any type of carbon fiber or graphite fiber can be used depending on the application.

<Method for producing epoxy resin composition>
Although the epoxy resin composition of this invention is not limited to this, For example, it is obtained by mixing each component mentioned above. Examples of the method for mixing each component include a method using a mixer such as a three-roll mill, a planetary mixer, a kneader, a homogenizer, and a homodisper.
The epoxy resin composition can be used, for example, in the production of a prepreg by impregnating a reinforcing fiber assembly as described later. In addition, a film of the present epoxy resin composition can be obtained by applying the epoxy resin composition to a release paper or the like and curing it.

<Film made of epoxy resin composition>
One embodiment of the molded article of the present invention is the use as a film. This film is useful as an intermediate material for producing a prepreg, and also as a surface protective film or an adhesive film by being cured after being attached to a substrate.
Moreover, although the usage method is not limited to this, it is preferable to apply | coat the epoxy resin composition of this invention to the surface of base materials, such as a release paper. The obtained coating layer may be used as a film by being stuck to another substrate while being uncured and cured, or may be used as a film by curing the coating layer itself.

<Prepreg>
The prepreg of the present invention is obtained by impregnating a reinforcing fiber assembly with the above-described epoxy resin composition of the present invention. As a method for impregnating the reinforcing fiber assembly with the epoxy resin composition, a known method may be used, for example, a wet method in which the epoxy resin composition is dissolved in a solvent such as methyl ethyl ketone or methanol to lower the viscosity and then impregnated. Examples thereof include a hot melt method (dry method) and the like, which are impregnated after the viscosity is lowered by heating, but is not limited thereto.

  The wet method is a method in which a reinforcing fiber is immersed in a solution of an epoxy resin composition, then pulled up, and the solvent is evaporated using an oven or the like. On the other hand, in the hot melt method, a method of directly impregnating reinforcing fibers with an epoxy resin composition whose viscosity has been reduced by heating, and a film in which the epoxy resin composition is once coated on release paper or the like are prepared, There is a method in which the reinforcing fiber is impregnated with resin by overlapping the film from both sides or one side of the reinforcing fiber and heating and pressing. The hot melt method is preferable because there is substantially no solvent remaining in the prepreg.

<Reinforcing fiber>
The reinforcing fiber of the present invention is a reinforcing fiber substrate and is preferably in the form of a sheet. The reinforcing fiber may be one in which reinforcing fibers are arranged in a single direction, or may be arranged in a random direction. Examples of the form of the reinforcing fiber include a woven fabric and a non-woven fabric of reinforcing fiber, and a sheet in which long fibers of the reinforcing fiber are aligned in one direction. The reinforcing fiber is preferably a sheet composed of a bundle of reinforcing fibers in which long fibers are aligned in a single direction from the viewpoint that a fiber-reinforced composite material having a high specific strength and high specific modulus can be formed. From the viewpoint of easy handling, a woven fabric of reinforcing fibers is preferable.

  Examples of the material of the reinforcing fiber include glass fiber, carbon fiber (including graphite fiber), aramid fiber, and boron fiber. The reinforced fiber base material is preferably a carbon fiber base material from the viewpoint of mechanical properties and weight reduction of the fiber reinforced composite material.

The fiber diameter of the carbon fiber is preferably 3 μm or more, and preferably 12 μm or less. If the fiber diameter of the carbon fiber is 3 μm or more, for example, in a process such as comb or roll for processing the carbon fiber, the carbon fiber moves laterally and the carbon fibers rub against each other, the carbon fiber and the roll surface, etc. When carbon fiber rubs, the carbon fibers are less likely to break or fluff. For this reason, the fiber reinforced composite material of the stable intensity | strength can be manufactured suitably. Moreover, if the fiber diameter of a carbon fiber is 12 micrometers or less, carbon fiber can be manufactured by a normal method. The number of carbon fibers in the carbon fiber bundle is preferably 1,000 to 70,000.

  From the viewpoint of the rigidity of the fiber-reinforced composite material, the strand tensile strength of the carbon fiber is preferably 1 to 9 GPa, more preferably 1.5 to 9 GPa, and the strand tensile elastic modulus of the carbon fiber is preferably 150 to 1,000 GPa, 200 -1,000 GPa is more preferred. The strand tensile strength and strand tensile elastic modulus of the carbon fiber are values measured in accordance with JIS R 7601: 1986.

<Fiber reinforced plastic>
The fiber reinforced plastic of the present invention is composed of a cured product of the above-described epoxy resin composition of the present invention and a reinforced fiber. The fiber reinforced plastic of the present invention is not limited to this, but for example, it is obtained by laminating the above-described prepreg of the present invention and then molding it by a method of heat curing a curable resin while applying pressure to the laminate. It is done.

<Molding method>
The fiber reinforced plastic molding method of the present invention includes a press molding method, an autoclave molding method, a bagging molding method, a wrapping tape method, an internal pressure molding method, a sheet wrap molding method, and an epoxy resin composition for reinforcing fiber filaments and preforms. Examples include RTM (Resin Transfer Molding), VaRTM (Vacuum Assisted Resin Transfer Molding), filament winding, RFI (Resin Film Infusion), etc. It is not limited to the method.

The wrapping tape method is a method in which a prepreg is wound around a mandrel or the like and a tubular body made of fiber reinforced plastic is formed, and is preferably used when producing a rod-like body such as a golf shaft or a fishing rod. More specifically, a prepreg is wound around a mandrel, a wrapping tape made of a thermoplastic film is wound around the outside of the prepreg for fixing and applying pressure, and the resin is heated and cured in an oven, and then a cored bar. This is a method for extracting a fiber and obtaining a fiber-reinforced plastic tubular body.
Also, the internal pressure molding method is to set a preform in which a prepreg is wound on an internal pressure applying body such as a tube made of a thermoplastic resin in a mold, and then introduce a high pressure gas into the internal pressure applying body to apply pressure. At the same time, the mold is heated and molded. The heating temperature is not particularly limited, but a higher temperature is preferable because the molding time can be shortened. Specifically, it is preferably 1 20 ° C. or higher, and more preferably 1 40 ° C. or higher. However, if the temperature is too high, it will take a very long time to lower the temperature of the mold, or if the prepreg is set without lowering the temperature, the curing will start and the resin will not spread to every corner of the final molded product. There is also. 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 using the epoxy resin composition of the present invention as a matrix resin 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, tennis and badminton racket applications, hockey stick applications, and ski pole applications. Furthermore, in general industrial applications, structural materials for moving bodies such as automobiles, ships, and railway vehicles, drive shafts, leaf springs, windmill blades, pressure vessels, flywheels, paper rollers, roofing materials, cables, and repair reinforcement materials, etc. Is preferably used.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited at all by these Examples.

<Raw materials>
<Component (A)>
Bisphenol A epoxy resin (Mitsubishi Chemical Corporation, product name: jER828)
4,4′-Diaminodiphenylsulfone (manufactured by Wakayama Seika Co., Ltd., product name: Seika Cure S)

  An epoxy resin having an epoxy equivalent of 266 g / eq, 100 parts by mass of a bisphenol A type epoxy resin having a number average molecular weight of 370, and 9 parts by mass of 4,4′-diaminodiphenylsulfone synthesized by the following procedure were mixed at 170 ° C. And reacted for 1 hour (preliminary reaction) to obtain component (A) (epoxy equivalent 266 g / eq, viscosity (90 ° C.) 1.3 Pa · s).

<Component (B)>
Novolac type polyfunctional epoxy resin (manufactured by DIC Corporation, trade name: N775)

<Ingredient (C)>
Epoxy resin having a bisphenol skeleton structure and a linear hydrocarbon structure having 6 or more carbon atoms, and / or an epoxy resin having a bisphenol skeleton structure and a polypropylene glycol skeleton structure having 4 or more ether oxygen atoms (DIC stock) (Product name: Epicron EXA-4816 and Epicron EXA-4850)

<Component (D)>
Dicyandiamide (Evonik Japan Co., Ltd., trade name: DICYANEX1400F)

<Ingredient (E)>
3-Phenyl-1,1-dimethylurea (Hodogaya Chemical Co., Ltd., trade name: Omicure 94)

<Other ingredients>
Bisphenol A type epoxy resin (Mitsubishi Chemical Corporation, trade name: jER1002)

<Epoxy resin composition>
(Examples 1-3, Comparative Examples 1-4)
From the raw materials shown in Table 1, components other than the curing agent were weighed into a glass flask and heated and mixed at 100 ° C. to obtain a uniform epoxy resin main agent. Next, the obtained epoxy resin main ingredient is 6
After cooling to 0 ° C. or lower, a curing agent and a curing aid were weighed and added, and uniformly dispersed by heating and mixing at 60 ° C. to obtain an epoxy resin composition. Next, this epoxy resin composition was cast with a 2 mm thick Teflon (registered trademark) spacer sandwiched between glass plates and cured by heating at 140 ° C. for 30 minutes to obtain a cured resin plate.

<Method for measuring bending characteristics of cured resin plate>
A universal testing machine (manufactured by INSTRON Co., Ltd.) equipped with a 500 N load cell by processing a cured resin plate having a thickness of 2 mm obtained by the procedure for producing a cured resin plate of the epoxy resin composition into a test piece (length 60 mm × width 8 mm). , Product name: INSTRON 5565), and the bending characteristics of the resin plate were measured. In an environment of a temperature of 23 ° C. and a humidity of 50% RH, using a three-point bending jig (indenter R = 3.2 mm, support R = 1.6 mm), the distance between the supports (L) and the thickness of the test piece (d) Under the condition of the ratio L / d = 16, the bending strength, bending elastic modulus, and bending elongation of the test piece were measured.

<Measurement of heat resistance>
A resin plate having a thickness of 2 mm is processed into a test piece (length 55 mm × width 12.5 mm), and a rheometer (product name: ARES-RDATA, manufactured by Instruments) is used to measure frequency 1
The log G ′ is plotted against the temperature at a heating rate of 5 ° C./min, and the temperature at the intersection of the approximate straight line of the flat region of log G ′ and the approximate straight line of the region where G ′ transitions is the glass transition temperature ( G '
-Tg).

<Consideration of Examples 1-3>
Except having set it as the composition shown in Table 1, it carried out similarly to Example 1, and obtained the epoxy resin composition and the cured resin board, and performed the same measurement. In either case, the elongation of the resin plate, which is a cured product of the epoxy resin composition, and G′-Tg are high.

<Consideration of Comparative Examples 1 and 2>
Except having set it as the composition shown in Table 1, it carried out similarly to Example 1, and obtained the epoxy resin composition and the cured resin board, and performed the same measurement. As shown in Table 1, since the resin plate that is a cured product of the epoxy resin composition of Comparative Examples 1 and 2 does not contain the component (A), the elongation and G′-Tg are low.

<Consideration of Comparative Example 3>
Except having set it as the composition shown in Table 1, it carried out similarly to Example 1, and obtained the epoxy resin composition and the cured resin board, and performed the same measurement. As shown in Table 1, since the resin plate that is a cured product of the epoxy resin composition of Comparative Example 3 does not contain the component (B), the elongation is high, but G′-Tg is low.

<Consideration of Comparative Example 4>
Except having set it as the composition shown in Table 1, it carried out similarly to Example 1, and obtained the epoxy resin composition and the cured resin board, and performed the same measurement. As shown in Table 1, since the resin plate that is a cured product of the epoxy resin composition of Comparative Example 4 does not contain the component (C), G′-Tg is high, but the elongation is low.

  Examples of the epoxy resin having a sulfur atom in the molecule include a bisphenol S type epoxy resin and an epoxy resin having a thio skeleton, which can be used in the present invention and are considered to have the same effect as the component (A). .

  According to the epoxy resin composition of the present invention, a fiber reinforced composite resin having excellent mechanical properties, particularly excellent fracture strain, can be cured in a short time even at a low temperature and used as a matrix resin for a prepreg. A molded body can be obtained. Therefore, according to the present invention, a wide range of molded products having high productivity, high efficiency, and excellent mechanical properties, for example, molded products for sports / leisure such as shafts for golf clubs, and molded products for industrial use such as aircraft, etc. can do.

Claims (8)

An epoxy resin composition comprising the following component (A), component (B), component (C) and component (D).
Component (A): reaction product of epoxy resin and amine compound having at least one sulfur atom in the molecule, and / or epoxy resin having at least one sulfur atom in the molecule Component (B): novolac type epoxy resin Component (C): an epoxy resin having a bisphenol skeleton structure and a linear hydrocarbon structure having 6 or more carbon atoms, and / or a polypropylene glycol skeleton structure having a bisphenol skeleton structure and 4 or more ether oxygen atoms Epoxy resin Component (D): Curing agent   The epoxy resin composition according to claim 1, wherein the content of the component (A) in the epoxy resin composition is 3 to 50 parts by mass with respect to 100 parts by mass of the epoxy resin composition.   The epoxy resin composition according to claim 1 or 2, wherein a content of the component (C) in the epoxy resin composition is 5 to 20 parts by mass with respect to 100 parts by mass of the epoxy resin composition.   The epoxy resin composition according to any one of claims 1 to 3, wherein the component (D) is an amine curing agent. Furthermore, the epoxy resin composition in any one of Claims 1-4 containing the following component (E).
Component (E): Urea compound A prepreg comprising a reinforcing fiber and an epoxy resin composition containing the following component (A), component (B), component (C), and component (D) as a matrix resin.
Component (A): reaction product of epoxy resin and amine compound having at least one sulfur atom in the molecule, and / or epoxy resin having at least one sulfur atom in the molecule Component (B): novolac type epoxy resin Component (C): an epoxy resin having a bisphenol skeleton structure and a linear hydrocarbon structure having 6 or more carbon atoms, and / or a polypropylene glycol skeleton structure having a bisphenol skeleton structure and 4 or more ether oxygen atoms Epoxy resin Component (D): Curing agent   The prepreg according to claim 6, wherein the reinforcing fibers are carbon fibers.   A cured product of a laminate in which two or more of the prepregs according to any one of claims 6 to 7 are laminated.