JP5747763B2 - Epoxy resin composition, prepreg and fiber reinforced composite material - Google Patents

Description

  The present invention relates to an epoxy resin composition preferably used as a matrix resin of a fiber-reinforced composite material suitable for sports applications and general industrial applications, a prepreg using the same as a matrix resin, and a fiber-reinforced composite obtained by curing the prepreg It relates to materials.

  Fiber reinforced composite materials using carbon fibers or aramid fibers as reinforcing fibers make use of their high specific strength and specific elastic modulus to make structural materials such as aircraft and automobiles, sports such as tennis rackets, golf shafts and fishing rods. Widely used in general industrial applications. As a method for producing these fiber reinforced composite materials, a method is often used in which a prepreg, which is a sheet-like intermediate material in which reinforcing fibers are impregnated with a matrix resin, is laminated and then cured. The method using a prepreg has an advantage that a high-performance fiber-reinforced composite material can be easily obtained because the orientation of the reinforcing fibers can be strictly controlled and the degree of freedom in designing the laminated structure is high. As the matrix resin used for the prepreg, a thermosetting resin is mainly used from the viewpoint of heat resistance and productivity, and an epoxy resin is preferably used from the viewpoint of mechanical properties such as adhesion to reinforcing fibers.

  In recent years, in addition to the movement to reduce weight by replacing conventional materials such as metal with fiber reinforced composite materials, there has been an active movement for further weight reduction of the fiber reinforced composite materials themselves in various applications. As a method for achieving weight reduction, there is a method in which a reinforced fiber having a higher elastic modulus is applied and the weight is reduced while maintaining the rigidity of the fiber-reinforced composite material. However, when the elastic modulus of the reinforcing fiber is increased, strength characteristics such as fiber direction compressive strength tend to be lowered. In order to improve strength characteristics such as fiber direction compressive strength, it is effective to improve the elastic modulus of the epoxy resin used as the matrix resin.

  Examples of the method for improving the elastic modulus of the epoxy resin include addition of an inorganic filler such as carbon nanotube and blending of an amine type epoxy resin having a high elastic modulus.

  For example, in Patent Document 1, by adding an amine-type epoxy resin having a high elastic modulus, the elastic modulus of the epoxy resin is improved, and has a strong correlation with the fiber direction compressive strength of the fiber reinforced composite material to which this is applied as a matrix resin. A significant improvement in fiber direction bending strength has been observed. However, in this method, since the toughness of the epoxy resin is lowered, the impact resistance is lowered.

  In order to improve the impact resistance of the fiber reinforced composite material, it is necessary to improve the elongation of the reinforcing fiber constituting the fiber reinforced composite material, the plastic deformation ability and the toughness of the epoxy resin. Of these, it is particularly important to improve the toughness of the epoxy resin.

  Conventionally, as a method for improving the toughness of an epoxy resin, a method of blending a rubber component having excellent toughness or a thermoplastic resin has been tried. However, since the elastic modulus and glass transition temperature of rubber are significantly lower than those of epoxy resin, when blended with epoxy resin, the elastic modulus and glass transition temperature of matrix resin decrease, and the balance between toughness and elastic modulus. Is difficult to take. Moreover, as a method of blending the thermoplastic component, for example, by adding a block copolymer such as a copolymer composed of styrene-butadiene-methyl methacrylate or a block copolymer composed of butadiene-methyl methacrylate, Methods for greatly improving the toughness of epoxy resins have been proposed (Patent Documents 2 and 3). However, these methods have problems such as reduced heat resistance, deteriorated processability due to thickening, and reduced quality such as void generation. Also, this method has an insufficient elastic modulus.

  As a method for improving the balance between elastic modulus and toughness, a method is disclosed in which a diglycidyl ether type epoxy resin having a specific number average molecular weight and an epoxy resin having an SP value different from that in a specific range are combined. However, this method is not only insufficient in balance between elastic modulus and toughness but also tends to increase viscosity.

JP-A-62-1717 International Publication No. 2006/075153 Pamphlet Special Table 2003-535181 International Publication No. 2009/107697 Pamphlet

  The object of the present invention is to improve the disadvantages of the prior art and to cure a cured resin having both excellent elastic modulus and toughness (herein, the cured resin means a cured epoxy resin composition. And an epoxy resin composition having a low viscosity and excellent impregnation between reinforcing fibers, a prepreg using the epoxy resin composition, and a fiber-reinforced composite material. is there.

  As a result of intensive studies to solve the above problems, the present inventors have found an epoxy resin composition having the following constitution, and have completed the present invention. That is, this invention consists of the following structures.

(I) An epoxy resin composition comprising the following [A] to [D], wherein [A] to [C] satisfy the following blending ratio with respect to 100 parts by mass of all epoxy resin components: The cured resin obtained by curing the epoxy resin composition has a phase separation structure having [A] rich phase and [B] rich phase, and the phase separation structure period is 1 nm to 5 μm. An epoxy resin composition.

[A] Bisphenol F type epoxy resin having a softening point of 90 ° C. or higher 30 to 50 parts by mass [B] Trifunctional or higher amine type epoxy resin 30 to 50 parts by mass [C] Bisphenol F type epoxy resin having a number average molecular weight of 450 or less 10 -40 mass parts [D] Hardener (However, the total amount of epoxy resin [A]-[C] does not exceed 100 mass parts.)

(II) The epoxy resin composition according to (I) , wherein the epoxy resin [B] is a trifunctional aminophenol type epoxy resin.

(III) The epoxy resin composition according to (I) or (II) , wherein the curing agent [D] is dicyandiamide or a derivative thereof.

(IV) Furthermore, at least one block copolymer [E] selected from the group consisting of SBM, BM, and MBM (wherein each of the above blocks is linked by a covalent bond) Or is linked to one block via one covalent bond formation and linked to the other block via another covalent bond formation, and block M is a polymethylmethacrylate A block made of a homopolymer or a copolymer containing at least 50% by mass of methyl methacrylate, block B is incompatible with block M, its glass transition temperature is 20 ° C. or lower, and block S is contained in blocks B and M Incompatible and the glass transition temperature of the block B is higher than the glass transition temperature of the block B) to 100 parts by mass of all epoxy resin components To include 1 to 10 parts by weight, the (I) ~ epoxy resin composition according to any one of (III).

(V) The epoxy resin composition according to (IV) , wherein block B of the block copolymer in the block copolymer [E] is poly1,4-butadiene or poly (butyl acrylate).

(VI) Obtained by preparing epoxy resins [A] to [C] and a curing agent [D], or epoxy resins [A] to [C], a curing agent [D] and a block copolymer [E]. The viscosity at 80 ° C. of the epoxy resin composition is 0.5 to 200 Pa · s, and the epoxy resins [A] to [C], or the epoxy resins [A] to [C] and the block copolymer [E]. Any of (I) to (V) above, wherein the resin toughness value of the cured resin obtained by reacting and curing the epoxy resin composition comprising the curing agent [D] is 1.3 MPa · m ^0.5 or more. the epoxy resin composition according to any.

(VII) A prepreg comprising the epoxy resin composition according to any one of (I) to (VI) and a reinforcing fiber.

(VIII) A fiber-reinforced composite material obtained by curing the prepreg described in (VII) .

(IX) A fiber-reinforced composite material comprising a resin cured product obtained by curing the epoxy resin composition according to any one of (I) to (VI) and reinforcing fibers.

  According to the present invention, an epoxy resin composition in which a fine phase separation structure of an epoxy resin is formed at the time of curing, gives a cured resin having a high elastic modulus and high toughness, and has a low viscosity and excellent impregnation between reinforcing fibers. Can provide things. Moreover, the fiber reinforced composite material using the epoxy resin composition of the present invention as a matrix resin has both excellent static strength characteristics and impact resistance.

Embodiments of the present invention, with respect to [A] ~ [C] is 100 parts by weight total epoxy resin component described below, meet the following blending ratio, the resin cured product obtained by curing the epoxy resin composition [A] an epoxy resin composition having a phase separation structure comprising a rich phase and a [B] rich phase, a phase separation structure period of 1 nm to 5 μm, and a curing agent [D]. .

[A] Bisphenol F type epoxy resin having a softening point of 90 ° C. or higher 30 to 50 parts by mass [B] Trifunctional or higher amine type epoxy resin 30 to 50 parts by mass [C] Bisphenol F type epoxy resin having a number average molecular weight of 450 or less 10 To 40 parts by mass [D] curing agent
(However, the total amount of epoxy resins [A] to [C] does not exceed 100 parts by mass.)

As such epoxy resin [A], it is necessary to include 30 to 50 parts by weight of 100 parts by weight of total epoxy resin of bisphenol type epoxy resin having a softening point of above 90 ° C.. If the softening point of the bisphenol type epoxy resin [A] is less than 90 ° C., the toughness of the resin cured product of the epoxy resin composition may be insufficient. Moreover, when it is less than 20 parts by mass, the toughness is insufficient, and when it exceeds 50 parts by mass, not only the elastic modulus and heat resistance of the resin cured product are insufficient, but also the viscosity of the epoxy resin composition becomes too high. If the viscosity of the epoxy resin composition becomes too high, the epoxy resin composition cannot be sufficiently impregnated between the reinforcing fibers when the prepreg is produced. For this reason, voids are generated in the obtained fiber reinforced composite material, and the strength of the fiber reinforced composite material is lowered.

  As the bisphenol type epoxy resin [A], bisphenol A type, bisphenol F type, bisphenol AD type, bisphenol S type epoxy resin, or their halogen, alkyl-substituted products, hydrogenated products and the like are used.

  Examples of commercially available epoxy resin [A] include “jER (registered trademark)” 1004AF, 1007, 1009P, 1010P, 4005P, 4007P, 4009P, and 4010P (manufactured by Mitsubishi Chemical Corporation) as bisphenol type epoxy resins. It is done. Among them, bisphenol A type epoxy resin or bisphenol F type epoxy resin is preferable, and bisphenol F type epoxy resin is more preferably used because of a good balance between heat resistance, elastic modulus, and toughness.

  As epoxy resin [B], it is necessary to include 30-50 parts by mass of trifunctional or higher amine type epoxy resin out of 100 parts by mass of all epoxy resins. When it is less than 30 parts by mass, the elastic modulus of the obtained resin cured product is insufficient. Moreover, when it exceeds 50 mass parts, the plastic deformation capability and toughness of a resin cured material are insufficient. Of the tri- or higher functional amine-type epoxy resins, the tri-functional amine-type epoxy resins are preferable because they give the cured resin a good balance between elastic modulus and toughness. Furthermore, among the trifunctional amine type epoxy resins, aminophenol type epoxy resins have relatively high toughness and are more preferable.

  Examples of the trifunctional or higher amine type epoxy resin [B] include amine types such as tetraglycidyldiaminodiphenylmethane, tetraglycidyldiaminodiphenylsulfone, tetraglycidyldiaminodiphenylether, triglycidylaminophenol, triglycidylaminocresol, and tetraglycidylxylylenediamine. Epoxy resins, epoxy resins having a triglycidyl isocyanurate skeleton, or their halogen, alkyl-substituted products, hydrogenated products, and the like are used.

  Examples of the tetraglycidyldiaminodiphenylmethane include “Sumiepoxy (registered trademark)” ELM434 (manufactured by Sumitomo Chemical Co., Ltd.), YH434L (manufactured by Nippon Steel Chemical Co., Ltd.), and “jER (registered trademark)” 604 (Mitsubishi Chemical Corporation). ), “Araldide (registered trademark)” MY720, MY721 (manufactured by Huntsman Advanced Materials), etc. can be used. As tetraglycidyl diaminodiphenyl ether, 3,3′-TGDDE (manufactured by Toray Fine Chemical Co., Ltd.) or the like can be used. As triglycidylaminophenol or triglycidylaminocresol, "Araldide (registered trademark)" MY0500, MY0510, MY0600 (manufactured by Huntsman Advanced Materials), "jER (registered trademark)" 630 (Mitsubishi Chemical Corporation) ) Etc. can be used. As tetraglycidylxylylenediamine and hydrogenated products thereof, “TETRAD (registered trademark)”-X, “TETRAD (registered trademark)”-C (manufactured by Mitsubishi Gas Chemical Co., Inc.) and the like can be used. As a commercial item of tetraglycidyl diaminodiphenyl sulfone, TG3DAS (manufactured by Konishi Chemical Industry Co., Ltd.) can be mentioned.

  As this epoxy resin [C], it is necessary to use 10 to 40 parts by mass of 100 parts by mass of the total epoxy resin of bisphenol F type epoxy resin having a number average molecular weight of 450 or less that gives a high elastic modulus. Preferably, 20 to 40 parts by mass of a bisphenol F type epoxy resin having a number average molecular weight of 450 or less is included in 100 parts by mass of the total epoxy resin. When exceeding 40 mass parts, the toughness of the resin cured material obtained tends to be insufficient. Moreover, when it is less than 10 mass parts, the viscosity of this epoxy resin composition may become high. Furthermore, when the number average molecular weight of the bisphenol F-type epoxy resin is larger than 450, the viscosity of the epoxy resin composition tends to be high, so that it becomes difficult for the epoxy resin composition to impregnate between the reinforcing fibers in the prepreg manufacturing process. It tends to be difficult to improve the fiber content.

  In addition, as a method of measuring the number average molecular weight as referred to in the present invention, for example, the following method may be mentioned. “HLC (registered trademark)” 8220GPC (manufactured by Tosoh Corporation) is used as a measuring apparatus, UV-8000 (254 nm) is used as a detector, and TSK-G4000H (manufactured by Tosoh Corporation) is used as a column. The epoxy resin was dissolved in THF at a concentration of 0.1 mg / ml, and the sample retention time measured at a flow rate of 1.0 ml / min and a temperature of 40 ° C. was calculated using the polystyrene calibration sample retention time as the molecular weight. Calculate by converting to

  The epoxy resin curing agent of the curing agent [D] in the present invention is not particularly limited as long as it cures an epoxy resin. Amines such as aromatic amines and alicyclic amines, acid anhydrides, polyaminoamides , Organic acid hydrazides, isocyanates and the like.

  The amine curing agent is preferable because it is excellent in mechanical properties and heat resistance, and diaminodiphenylsulfone, diaminodiphenylmethane, which are aromatic amines, dicyandiamide or a derivative thereof, which is an aliphatic amine, hydrazide compounds, and the like are used. Examples of such commercially available dicyandiamide include DICY-7 and DICY-15 (manufactured by Mitsubishi Chemical Corporation). The dicyandiamide derivative is obtained by bonding various compounds to dicyandiamide, and includes a reaction product with an epoxy resin, a reaction product with a vinyl compound or an acrylic compound.

  Furthermore, it is preferable to blend dicyandiamide or a derivative thereof as a curing agent [D] into a resin as a powder from the viewpoint of storage stability at room temperature and viscosity stability during prepreg formation. When dicyandiamide or a derivative thereof is blended into a resin as a powder, the average particle size is preferably 10 μm or less, more preferably 7 μm or less. For example, when the reinforcing fiber bundle is impregnated into the reinforcing fiber bundle by heating and pressing in the prepreg manufacturing process, dicyandiamide or a derivative thereof having a particle size of more than 10 μm does not enter the reinforcing fiber bundle and remains on the surface of the fiber bundle. There is a case.

  Moreover, it is preferable that the total amount of this hardening | curing agent contains the quantity from which an active hydrogen group becomes the range of 0.6-1.0 equivalent with respect to the epoxy group of all the epoxy resin components, More preferably, it is 0.7-0. The amount is in the range of 9 equivalents. Here, the active hydrogen group means a functional group that can react with an epoxy group. Examples of the active hydrogen group include an amino group and a hydroxyl group. When the active hydrogen group is less than 0.6 equivalent, the reaction rate, heat resistance and elastic modulus of the cured resin are insufficient, and the glass transition temperature and strength of the fiber reinforced composite material may be insufficient. When the active hydrogen group exceeds 1.0 equivalent, the reaction rate, glass transition temperature, and elastic modulus of the cured resin are sufficient, but the plastic deformation ability is insufficient, so the impact resistance of the fiber reinforced composite material May be insufficient.

  Each curing agent may be used in combination with a curing accelerator or other epoxy resin curing agent. Examples of the curing accelerator to be combined include ureas, imidazoles and Lewis acids.

  Examples of the urea compound include N, N-dimethyl-N ′-(3,4-dichlorophenyl) urea, toluene bis (dimethylurea), 4,4′-methylenebis (phenyldimethylurea), and 3-phenyl-1 , 1-dimethylurea and the like can be used. Examples of commercially available urea compounds include DCMU99 (manufactured by Hodogaya Chemical Co., Ltd.), “Omicure (registered trademark)” 24, 52, and 94 (manufactured by CVC Specialty Chemicals, Inc.).

  Examples of commercially available imidazoles include 2MZ, 2PZ, and 2E4MZ (manufactured by Shikoku Kasei Co., Ltd.). Lewis acids include boron trifluoride / piperidine complex, boron trifluoride / monoethylamine complex, boron trifluoride / triethanolamine complex, boron trichloride / octylamine complex, etc. Can be mentioned.

  Of these, urea compounds are preferably used from the balance between storage stability and promoting ability. It is preferable that the compounding quantity of this urea compound contains 1-3 mass parts with respect to 100 mass parts of all the epoxy resin components. When the blending amount of the urea compound is less than 1 part by mass, the reaction does not proceed sufficiently, and the elastic modulus and heat resistance of the cured resin product tends to be insufficient. Moreover, when the compounding quantity of this urea compound exceeds 3 mass parts, since the self-polymerization reaction of an epoxy resin inhibits reaction with an epoxy resin and a hardening | curing agent, in addition to the toughness of a resin hardened | cured material, elasticity modulus Also decreases.

  In addition, the epoxy resin composition of the present invention contains an epoxy resin other than the epoxy resins [A] to [C] for the purpose of adjusting viscoelasticity and improving workability or the elastic modulus and heat resistance of the cured resin. , And can be added as long as the effects of the present invention are not lost. These may be added in combination of not only one type but also a plurality of types. Specifically, phenol novolac type epoxy resin, cresol novolac epoxy resin, resorcinol type epoxy resin, phenol aralkyl type epoxy resin, dicyclopentadiene type epoxy resin, epoxy resin having biphenyl skeleton, isocyanate modified epoxy resin, anthracene type epoxy resin Polyethylene glycol type epoxy resin, N, N′-diglycidylaniline, liquid bisphenol A type epoxy resin, and the like.

  Commercially available products of phenol novolac type epoxy resins include “Epicoat (registered trademark)” 152, 154 (manufactured by Mitsubishi Chemical Corporation), “Epicron (registered trademark)” N-740, N-770, N-775 ( As mentioned above, DIC Corporation) etc. are mentioned.

  As a commercial product of a cresol novolac type epoxy resin, “Epiclon (registered trademark)” N-660, N-665, N-670, N-673, N-695 (above, manufactured by DIC Corporation), “EOCN ( Registered trademark) "1020, 102S, 104S (Nippon Kayaku Co., Ltd.).

  Specific examples of the resorcinol type epoxy resin include “Denacol (registered trademark)” EX-201 (manufactured by Nagase ChemteX Corporation).

  Commercially available dicyclopentadiene type epoxy resins include “Epiclon (registered trademark)” HP7200, HP7200L, HP7200H (above, manufactured by DIC Corporation), “TACTIX (registered trademark)” 558 (manufactured by Huntsman Advanced Materials) XD-1000-1L, XD-1000-2L (manufactured by Nippon Kayaku Co., Ltd.), and the like.

  Examples of commercially available epoxy resins having a biphenyl skeleton include “Epicoat (registered trademark)” YX4000H, YX4000, YL6616 (manufactured by Mitsubishi Chemical Corporation), NC-3000 (manufactured by Nippon Kayaku Co., Ltd.), and the like. It is done.

  Examples of commercially available isocyanate-modified epoxy resins include “AER (registered trademark)” 4152 (made by Asahi Kasei E-Materials Co., Ltd.) and XAC4151 (made by Asahi Kasei Chemicals Co., Ltd.) having an oxazolidone ring.

  Examples of commercially available anthracene epoxy resins include YX8800 (manufactured by Mitsubishi Chemical Corporation).

  Examples of commercially available polyethylene glycol epoxy resins include “Denacol (registered trademark)” EX810, 811, 850, 851, 821, 830, 841, 861 (manufactured by Nagase ChemteX Corporation).

  As a commercially available product of N, N′-diglycidylaniline, GAN (Nippon Kayaku Co., Ltd.) can be mentioned.

  Examples of commercially available liquid bisphenol A type epoxy resins include “jER (registered trademark)” 828 (manufactured by Mitsubishi Chemical Corporation).

  In addition, the epoxy resin composition of the present invention is a thermoplastic that is soluble in epoxy resin to control viscoelasticity and improve mechanical properties such as tack and drape characteristics of prepreg and impact resistance of fiber reinforced composite materials. Resin, organic particles such as rubber particles and thermoplastic resin particles, inorganic particles, and the like can be blended.

  As the thermoplastic resin soluble in the epoxy resin, a thermoplastic resin having a hydrogen bondable functional group that can be expected to improve the adhesion between the resin and the reinforcing fiber is preferably used. Examples of the hydrogen bondable functional group include an alcoholic hydroxyl group, an amide bond, a sulfonyl group, and a carboxyl group.

  Examples of the thermoplastic resin having an alcoholic hydroxyl group include polyvinyl acetal resins such as polyvinyl formal and polyvinyl butyral, polyvinyl alcohol, and phenoxy resins. Examples of the thermoplastic resin having an amide bond include polyamide, polyimide, polyamideimide, and polyvinylpyrrolidone. Examples of the thermoplastic resin having a sulfonyl group include polysulfone. Polyamide, polyimide and polysulfone may have a functional group such as an ether bond and a carbonyl group in the main chain. The polyamide may have a substituent on the nitrogen atom of the amide group. Examples of the thermoplastic resin having a carboxyl group include polyester, polyamide, and polyamideimide.

  Commercially available thermoplastic resins that are soluble in epoxy resins and have hydrogen-bonding functional groups include Denkabutyral as a polyvinyl acetal resin and “Denkapoval (registered trademark)” as a polyvinyl alcohol resin (manufactured by Denki Kagaku Kogyo Co., Ltd.). ), “Vinylec (registered trademark)” (manufactured by Chisso Corporation), “Macromelt (registered trademark)” (manufactured by Henkel Co., Ltd.), “Amilan (registered trademark)” CM4000 (manufactured by Toray Industries, Inc.), As polyimide, “Ultem (registered trademark)” (manufactured by Subic Innovative Plastics), “Aurum (registered trademark)” (manufactured by Mitsui Chemicals), “Vespel (registered trademark)” (manufactured by DuPont) as PEEK polymer “Victrex (registered trademark)” (manufactured by Victrex), “UDEL (polysulfone) Recorded trademark) "(Solvay manufactured Advanced Polymers, Inc.), polyvinylpyrrolidone as don" Luviskol (registered trademark) "(BASF Japan Ltd. can be exemplified, Ltd.).

  Moreover, acrylic resin has high compatibility with an epoxy resin, and is preferably used for viscoelasticity control. Commercially available acrylic resins include “Dianar (registered trademark)” BR series (Mitsubishi Rayon Co., Ltd.), “Matsumoto Microsphere (registered trademark)” M, M100, M500 (Matsumoto Yushi Seiyaku Co., Ltd.) ) And the like.

  As the rubber particles, cross-linked rubber particles, and core-shell rubber particles obtained by graft polymerization of a different polymer on the surface of the cross-linked rubber particles are preferably used from the viewpoint of handleability and the like.

  Examples of commercially available core-shell rubber particles include “Paraloid (registered trademark)” EXL-2655, EXL-2611, and EXL-3387 (produced by Rohm and Haas Co., Ltd.) made of a butadiene / alkyl methacrylate / styrene copolymer. "Staffyroid (registered trademark)" AC-3355, TR-2122 (manufactured by Ganz), "Nanostrength (registered trademark)" M22, 51, 52, 53 (Manufactured by Arkema Co., Ltd.), “Kane Ace (registered trademark)” MX series (manufactured by Kaneka Corporation) and the like can be used.

  As the thermoplastic resin particles, polyamide particles and polyimide particles are preferably used. As commercial products of polyamide particles, SP-500 (manufactured by Toray Industries, Inc.), “Orgazol (registered trademark)” (manufactured by Arkema Co., Ltd.) and the like can be used.

  In the present invention, at least one block copolymer [E] (hereinafter abbreviated as a block copolymer) selected from the group consisting of SBM, BM, and MBM. Furthermore, it is effective to improve toughness and impact resistance while maintaining the excellent heat resistance of the epoxy resin composition.

  Here, the blocks represented by S, B, and M are linked by a covalent bond or by a covalent bond via some chemical structure.

  Block M is a homopolymer of polymethyl methacrylate or a copolymer containing at least 50% by weight of methyl methacrylate. Block B is incompatible with block M and has a glass transition temperature of 20 ° C. or lower. The glass transition temperature of the block B is a dynamic viscoelasticity measuring apparatus (RSAII: manufactured by Rheometrics, Inc. or rheometer ARES: TA instrument) regardless of whether the epoxy resin composition or the block copolymer alone is used. (Manufactured by Ment Co., Ltd.). That is, a plate-shaped sample having a thickness of 1 mm, a width of 2.5 mm, and a width of 34 mm is measured by sweeping it at a temperature of −100 to 250 ° C. and measuring a stress application period as 1 Hz, and blocking the maximum tan δ value. Let B be the glass transition temperature. Here, the sample is manufactured as follows. When the epoxy resin composition is used, the epoxy resin composition is degassed in a vacuum, and then heated at 130 ° C. in a mold set to a thickness of 1 mm by a 1 mm thick “Teflon (registered trademark)” spacer. By curing at a temperature for 2 hours, a plate-like resin cured product without voids is obtained, and when a block copolymer is used alone, a plate without voids is obtained similarly by using a biaxial extruder. It can cut and evaluate to the said size with a diamond cutter.

  Block S is incompatible with blocks B and M, and its glass transition temperature is higher than that of block B. The glass transition temperature or melting point of the block S is preferably 23 ° C. or higher, and more preferably 50 ° C. or higher. Examples of blocks S are obtained from aromatic vinyl compounds such as those obtained from styrene, α-methylstyrene or vinyltoluene, alkyl acids having an alkyl chain of 1 to 18 carbon atoms and / or alkyl esters of methacrylic acid. Things can be mentioned.

  In addition, when the block copolymer is SBM, any block of S, B, M is B, when the block copolymer is BM or MBM, It is preferable from the viewpoint of improving toughness that any of the blocks is compatible with the epoxy resin.

  The blending amount of the block copolymer [E] is preferably 1 to 10 parts by mass with respect to 100 parts by mass of all epoxy resin components from the viewpoint of mechanical properties and compatibility with the composite production process. Preferably it is 2-7 mass parts. When [E] is less than 1 part by mass, improvement in toughness and plastic deformation ability of the cured resin tends to be insufficient, and the impact resistance of the fiber-reinforced composite material may be insufficient. If it exceeds 10 parts by mass, the elastic modulus of the cured resin is lowered, the mechanical properties of the fiber reinforced composite material become insufficient, and the viscosity of the epoxy resin composition increases, which may cause problems in handling. is there.

  Introducing a monomer other than methyl methacrylate into the block M as a copolymerization component is preferably performed from the viewpoint of compatibility with the epoxy resin and control of various properties of the resin cured product. Such a monomer copolymerization component is not particularly limited and can be appropriately selected from the above viewpoints. Usually, in order to obtain compatibility with a highly polar epoxy resin, a highly polar monomer, particularly a water-soluble monomer. Are preferably used. Among these, acrylamide derivatives can be preferably used, and dimethylacrylamide is particularly preferably used. Moreover, a reactive monomer is also applicable as a monomer copolymerization component other than methyl methacrylate. Here, the reactive monomer means a monomer having a functional group capable of reacting with the oxirane group of the epoxy molecule or the functional group of the curing agent. Examples of the functional group capable of reacting include, but are not limited to, an oxirane group, an amine group, and a carboxyl group. As the reactive monomer, (meth) acrylic acid (methacrylic acid and acrylic acid are collectively abbreviated as (meth) acrylic acid) or any other monomer that generates (meth) acrylic acid by hydrolysis is used. You can also. The reactive monomer is preferably used in order to improve the compatibility between the block copolymer [E] and the epoxy resin and the interfacial adhesion between the [E] and the epoxy.

  The glass transition temperature of the block B is 20 ° C. or lower, preferably 0 ° C. or lower, more preferably −40 ° C. or lower. Such a glass transition temperature is preferably as low as possible from the viewpoint of toughness. However, when the temperature is lower than −100 ° C., there may be a problem in workability such as a roughened cutting surface when a fiber reinforced composite material is used.

  Block B is preferably an elastomer block and the monomers used to synthesize such elastomer blocks are butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene and 2-phenyl. It can be selected from -1,3-butadiene.

  Such block B is preferably selected from polydienes, in particular polybutadiene, polyisoprene and their random copolymers or partially or fully hydrogenated polydienes from the standpoint of toughness. Such partially or fully hydrogenated polydienes can be made according to conventional hydrogenation methods. Among the polybutadienes, poly 1,2-butadiene (glass transition temperature of about 0 ° C.) and the like are preferable, but poly 1,4-butadiene (glass transition) having the lowest glass transition temperature among the dienes listed above. More preferably, a temperature of about −90 ° C.) is used. This is because the use of the block B having a lower glass transition temperature is advantageous from the viewpoint of impact resistance and toughness.

  As a monomer used for synthesizing the block B of the elastomer, alkyl (meth) acrylate can also be used. Specific examples include ethyl acrylate (−24 ° C.), butyl acrylate (−54 ° C.), 2-ethylhexyl acrylate (−85 ° C.), hydroxyethyl acrylate (−15 ° C.), and 2-ethylhexyl methacrylate (−10 ° C.). Can be mentioned. Here, the numerical value shown in parentheses after the name of each acrylate is the glass transition temperature of the block B obtained when each acrylate is used. Of these, butyl acrylate is preferably used. The acrylate as a monomer for synthesizing these blocks B is incompatible with the acrylate of the block M containing at least 50% by mass of methyl methacrylate. Therefore, it is more preferable that the B block is mainly composed of poly1,4-butadiene, polybutyl acrylate, or poly (2-ethylhexyl acrylate).

  When the triblock copolymer MBM is used as the block copolymer [E], the two blocks M of the triblock copolymer MBM may be the same as or different from each other. Also, the molecular weight can be different due to the same monomer.

  When the triblock copolymer MBM and the diblock copolymer BM are used in combination as the block copolymer [E], the block M of the triblock copolymer MBM is diblock copolymer. The M block of the polymer B-M may be the same as or different from the M block, and the block B of the M-B-M triblock may be the same as or different from the diblock copolymer B-M.

  When the triblock copolymer SBM and the diblock copolymer BM and / or the triblock copolymer MBM are used in combination as the block copolymer [E], the triblock The block M of the copolymer SBM, the blocks M of the triblock copolymer MBM, and the block M of the diblock copolymer BM may be the same as or different from each other. The blocks B of the triblock copolymer SBM, the triblock copolymer MBM, and the diblock copolymer BM may be the same as or different from each other.

  The block copolymer used in the material of the present invention can be produced by anionic polymerization, and can be produced, for example, by the method described in EP 524,054 or EP 749,987.

  Specific examples of the triblock copolymer M-B-M include, as a copolymer consisting of methyl methacrylate-butyl acrylate-methyl methacrylate, Nanostrength M22 (manufactured by Arkema) or Nanostrength M22N having a polar functional group ( Arkema). Specific examples of the triblock copolymer S-B-M include a styrene-butadiene-methyl methacrylate copolymer such as Nanostrength 123, Nanostrength 250, Nanostrength 012, Nanostrength E20, Nanostrength E40 (manufactured by Arkema). , Manufactured by Arkema).

  For preparing the epoxy resin composition of the present invention, a kneader, a planetary mixer, a three-roll extruder, a twin-screw extruder, or the like is preferably used. [A], [B], and [C] are added as epoxy resins, and the temperature of the epoxy resin mixture is increased to an arbitrary temperature of 130 to 180 ° C. while stirring, and the epoxy resins [A], [B], [C, C] is uniformly dissolved. At this time, other components other than the curing agent / curing accelerator may be added and kneaded together. Thereafter, while stirring, the temperature is preferably lowered to 100 ° C. or lower, more preferably 80 ° C. or lower, and a curing agent and a curing accelerator are added and kneaded and dispersed. This method is preferably used because an epoxy resin composition having excellent storage stability can be obtained.

  Here, even when the epoxy resins [A] to [C] are in a state of being uniformly compatible with each other before curing, the spinodal decomposition occurs in the curing process, and the epoxy resin [A] rich phase and the epoxy resin [ B] There is a tendency to form a phase separation structure with the rich phase. Here, in the present invention, the phase separation structure refers to a structure in which two or more phases including an epoxy resin [A] rich phase and an epoxy resin [B] rich phase are separated. The epoxy resin [A] rich phase and the epoxy resin [B] rich phase refer to phases mainly comprising the epoxy resin [A] and the epoxy resin [B], respectively. Moreover, a main component means the component contained by the highest content rate in the said phase here. The phase separation structure may be a phase separation structure of three or more phases further including a phase mainly composed of components other than the epoxy resin [A] and the epoxy resin [B]. In the epoxy resin composition comprising the epoxy resins [A] to [C] and the curing agent [D] according to the present invention, a cured resin obtained by reacting and curing the epoxy resin [A] -rich phase and epoxy is obtained. Preferably, the resin [B] has a phase separation structure composed of a rich phase, and the phase separation structure period is 1 nm to 5 μm. Furthermore, a preferable phase separation structure period is 1 nm to 1 μm. In the curing process of the epoxy resin composition of the present invention, the epoxy resin [C] functions as a compatibilizing agent for the epoxy resins [A] and [B].

  Furthermore, when the block copolymer [E] is included, even if the epoxy resins [A] to [C] and the block copolymer [E] are uniformly compatible with each other before curing, In the curing process, spinodal decomposition tends to occur, and a phase separation structure tends to be formed by the three phases of the epoxy resin [A] rich phase, the epoxy resin [B] rich phase, and the block copolymer [E] rich phase. The epoxy resin composition comprising the epoxy resins [A] to [C], the curing agent [D] and the block copolymer [E] according to the present invention has a resin cured product obtained by reacting and curing at least epoxy. A phase separation structure comprising a resin [A] rich phase, an epoxy resin [B] rich phase, and a block copolymer [E], an epoxy resin [A] rich phase, an epoxy resin [B] rich phase, and a block The phase separation structure period of the copolymer [E] rich phase is preferably 1 nm to 5 μm, and the phase separation period of the block copolymer [E] rich phase is more preferably 1 nm to 1 μm.

  In the present invention, the phase separation structure refers to a structure in which two or more phases mainly composed of different components are formed. In the present invention, when the phase composed mainly of different components has a phase separation structure period of less than 1 nm, it is regarded as a state of being uniformly mixed at the molecular level, that is, a compatible state. Whether or not it is a phase separation structure can be determined by an electron microscope, a phase-contrast optical microscope, and various other methods.

  In the present invention, the structural period of phase separation is defined as follows. The phase separation structure includes a two-phase continuous structure and a sea-island structure. In the case of a biphasic continuous structure, three straight lines of a predetermined length are drawn randomly on the micrograph, the intersection of the straight line and the phase interface is extracted, the distance between adjacent intersections is measured, and the number average of these The value is the structure period. The predetermined length is set as follows based on a micrograph. When the structural period is expected to be on the order of 0.01 μm (0.01 μm or more and less than 0.1 μm), a photograph is taken at a magnification of 20,000 times, and a length of 20 mm drawn on the photograph (a length of 1 μm on the sample) In the same manner, when the phase separation structure period is expected to be on the order of 0.1 μm (0.1 μm or more and less than 1 μm), a photograph is taken at a magnification of 2,000 times, and the length is randomly 20 mm on the photograph. When the phase separation structure period is expected to be on the order of 1 μm (1 μm or more and less than 10 μm), a photograph is taken at a magnification of 200 times and a length of 20 mm is randomly selected on the photograph ( (Length of 100 μm above the sample). If the measured phase separation structure period is out of the expected order, the measurement is performed again at a magnification corresponding to the corresponding order.

  In the case of the sea-island structure, three predetermined areas are selected on the micrograph, and the number average value of the island phase sizes in the area is selected. The size of the island phase refers to the length of the shortest distance line drawn from the phase interface to one phase interface through the island phase. Even when the island phase is an ellipse, an indeterminate shape, or a circle or ellipse of two or more layers, the shortest distance passing through the island phase from the phase interface to one phase interface is used. The predetermined area is set as follows based on a micrograph. When the phase separation structure period is expected to be on the order of 0.01 μm (0.01 μm or more and less than 0.1 μm), a photograph is taken at a magnification of 20,000 times, and a 4 mm square region (on the sample) randomly selected on the photograph In the same way, if the phase separation structure period is expected to be on the order of 0.1 μm (0.1 μm or more and less than 1 μm), the photograph is taken at a magnification of 2,000 times. When the phase separation structure period is expected to be on the order of 1 μm (1 μm or more and less than 10 μm), the photograph is taken at a magnification of 200 times. 4 mm square area (20 μm square area on the sample) selected at random. If the measured phase separation structure period is out of the expected order, the measurement is performed again at a magnification corresponding to the corresponding order.

  The phase separation structure of the cured resin product can be observed with a scanning electron microscope or a transmission electron microscope. You may dye | stain with osmium etc. as needed. Dyeing can be performed by a usual method.

  By having such a phase separation structure, it becomes possible to achieve both elastic modulus and toughness. When the structural period is less than 1 nm, the cavitation effect cannot be exhibited, and not only the toughness is insufficient but also the elastic modulus is easily insufficient. In addition, when the thickness exceeds 5 μm, the structure period is large, so that the crack does not progress to the island phase and progresses only in the region of the sea phase, so that the cavitation effect cannot be expressed, and the toughness of the cured resin is not good. May be sufficient.

Further, when the phase separation structure period of the epoxy resin [A] rich phase and the epoxy resin [B] rich phase is less than 1 nm, at least one of the following adjustment methods is within the range not impairing the object of the present invention. By performing one or more methods, the phase separation structure period can be increased.
(1) The blending ratio of the epoxy resin [C] to the total epoxy resin is reduced.
(2) Increase the softening point of the epoxy resin [A].
(3) Lower the softening point of the epoxy resin [B].
(4) Increase the blending ratio of both epoxy resins [A] and [B].

Further, when the phase separation structure period of the epoxy resin [A] rich phase and the epoxy resin [B] rich phase exceeds 5 μm, at least one of the following adjustment methods is within the range not impairing the object of the present invention. By performing one or more methods, the phase separation structure period can be reduced.
(1) Increase the blending ratio of the epoxy resin [C] to the total epoxy resin.
(2) Lower the softening point of the epoxy resin [A].
(3) Increase the softening point of the epoxy resin [B].
(4) Reduce the blending ratio of both epoxy resins [A] and [B].

Further, when the phase separation structure period of the block copolymer [E] rich phase exceeds 5 μm, at least one of the following adjustment methods is performed within a range that does not impair the object of the present invention. As a result, the phase separation structure period can be reduced.
(1) The blending ratio of the block copolymer [E] is reduced.
(2) Lower the softening point of the epoxy resin [A].
(3) Increase the compounding ratio of the epoxy resin [B].

Further, the phase separation structure period of the block copolymer [E] rich phase is increased by performing at least one of the following adjustment methods within a range not impairing the object of the present invention. it can.
(1) Increase the blending ratio of the block copolymer [E].
(2) Increase the softening point of the epoxy resin [A].
(3) The blending ratio of the epoxy resin [B] is reduced.

When the epoxy resin composition of the present invention is used as a matrix resin for a prepreg, the viscosity at 80 ° C. of the epoxy resin composition is preferably 0.5 to 200 Pa · s from the viewpoint of processability such as tack and drape. . When the viscosity at 80 ° C. of the epoxy resin composition is less than 0.5 Pa · s, the produced prepreg is difficult to maintain its shape, and the prepreg may be cracked. Moreover, many resin flows are produced at the time of fiber-reinforced composite material molding, and there is a possibility that the reinforcing fiber content varies. When the viscosity at 80 ° C. exceeds 200 Pa · s, the epoxy resin composition cannot be sufficiently impregnated between the reinforcing fibers when the prepreg is produced. For this reason, voids are generated in the obtained fiber-reinforced composite material, and the strength of the fiber-reinforced composite material may be reduced. Furthermore, the viscosity at 80 ° C. of the epoxy resin composition may be in the range of 5 to 50 Pa · s because the resin is easily impregnated between the reinforcing fibers and a prepreg having a high fiber content can be manufactured in the prepreg manufacturing process. More preferred. The viscosity can be lowered by performing at least one of the following methods (1) to (2) within the range not impairing the object of the present invention, and the following (3) to (4 The viscosity can be increased by performing at least one of the methods.
(1) The viscosity is lowered using an epoxy resin [A] and / or [B] having a low softening point.
(2) Increase the number of parts by mass of the epoxy resin [C] to lower the viscosity.
(3) Increase viscosity using epoxy resin [A] and / or [B] having a high softening point.
(4) The addition of the thermoplastic resin increases the viscosity of the epoxy resin composition.

Here, the viscosity is a dynamic viscoelasticity measuring device (Rheometer RDA2: manufactured by Rheometrics or Rheometer ARES: manufactured by TA Instruments), a parallel plate having a diameter of 40 mm, and a temperature rising rate of 1. It refers to the complex viscoelastic modulus η ^* obtained by simply raising the temperature at 5 ° C./min and measuring at a frequency of 0.5 Hz and a gap of 1 mm.

In the epoxy resin composition of the present invention, the elastic modulus of the resin cured product is preferably in the range of 3.8 to 5.0 GPa. More preferably, it is 4.0 to 5.0 GPa. When the elastic modulus is less than 3.8 GPa, the static strength when the fiber-reinforced composite material is obtained may be insufficient. If it exceeds 5.0 GPa, the plastic deformation ability tends to be insufficient when the fiber reinforced composite material is used, and the impact strength of the fiber reinforced composite material may be insufficient. Here, the elastic modulus can be improved by performing at least one of the following methods within a range that does not impair the object of the present invention.
(1) A bisphenol F type epoxy resin having a high elastic modulus is used as the epoxy resin [A].
(2) Increase the number of parts by mass of the epoxy resin [B].
(3) An amine type epoxy is used as the epoxy resin [B], and an aminophenol type epoxy resin having a high elastic modulus is used.
(4) A bisphenol F type epoxy resin is used as the epoxy resin [C].

  Here, the curing temperature and curing time for obtaining such a resin cured product are not particularly limited, and depending on the curing agent and curing accelerator to be blended, the cost and productivity, the mechanical properties of the resulting resin cured product, heat resistance It can be appropriately selected from the viewpoints of properties and quality. For example, in a curing agent system in which dicyandiamide and DCMU are combined, a condition of curing at a temperature of 130 to 150 ° C. for 90 minutes to 2 hours is preferable, and when diaminodiphenyl sulfone is used, a temperature of 180 ° C. for 2 to 3 hours. Conditions for curing are preferred.

  Here, a method for measuring the elastic modulus of the cured resin in the present invention will be described. First, after defoaming the epoxy resin composition in a vacuum, the voids of the voids are cured by curing under a predetermined curing condition in a mold set to a thickness of 2 mm by a 2 mm thick “Teflon (registered trademark)” spacer. A cured plate-like resin is obtained. This cured resin product is cut out to a width of 10 mm and a length of 60 mm by a diamond cutter to obtain a sample for measuring the elastic modulus of the cured resin product. The obtained sample is measured by 3-point bending according to JIS K7171 (1994) using a universal testing machine (Instron) with a span of 32 mm and a crosshead speed of 100 mm / min. The average value of the number of samples n = 5 is defined as the elastic modulus of the resin cured product.

The resin toughness value of the cured resin obtained by curing the epoxy resin composition of the present invention is preferably 1.1 MPa · m ^0.5 or more. More preferably, it is 1.3 MPa · m ^0.5 or more. If the resin toughness value is less than 1.1 MPa · m ^0.5 , the impact resistance of the fiber-reinforced composite material may be insufficient. Here, within the scope of the present invention, the resin toughness value can be improved by performing at least one of the following methods.
(1) An epoxy resin [A] and / or [B] having a large number average molecular weight is used.
(2) Increase the number of parts by mass of the epoxy resin [A].
(3) A block copolymer [E] is blended.

  Here, the measurement of the resin toughness value of the cured resin will be described. First, after defoaming the epoxy resin composition in a vacuum, the voids of the voids are cured by curing under a predetermined curing condition in a mold set to a thickness of 6 mm with a 6 mm thick “Teflon (registered trademark)” spacer. A cured plate-like resin is obtained. The obtained cured resin is cut into a width of 12.7 mm and a length of 150 mm with a diamond cutter, a pre-crack of 5 to 7 mm is introduced from one end in the width direction, and a sample for measuring the resin toughness value of the cured resin is produced. . The initial precrack is introduced into the test piece by applying a razor blade cooled to the liquid nitrogen temperature to the test piece and applying an impact to the razor with a hammer. The resin toughness value of the cured resin is measured according to ASTM D5045 (1999) using the sample obtained above and using a universal testing machine (manufactured by Instron). The average value of the number of samples n = 5 is defined as the resin toughness value of the cured resin.

  The reinforcing fiber used in the present invention is not particularly limited, and glass fiber, carbon fiber, aramid fiber, boron fiber, alumina fiber, silicon carbide fiber and the like are used. Two or more of these fibers may be mixed and used. Among these, it is preferable to use carbon fibers from which a lightweight and highly rigid fiber-reinforced composite material can be obtained. Among these, carbon fibers having a tensile modulus of 230 to 800 GPa are preferably used, and carbon fibers having a tensile modulus of 280 GPa are more preferably used. When a high elastic modulus carbon fiber having a high elastic modulus of 230 to 800 GPa is combined with the epoxy resin composition of the present invention, the effect of the present invention is particularly prominent, and good impact resistance tends to be obtained. .

  The form of the reinforcing fiber is not particularly limited. For example, a long fiber aligned in one direction, a tow, a woven fabric, a mat, a knit, a braid, a short fiber chopped to a length of less than 10 mm, and the like are used. The term “long fiber” as used herein refers to a single fiber or fiber bundle that is substantially continuous by 10 mm or more. A short fiber is a fiber bundle cut to a length of less than 10 mm. In particular, for applications requiring high specific strength and specific elastic modulus, an array in which reinforcing fiber bundles are aligned in a single direction is most suitable.

  The method for producing the fiber-reinforced composite material of the present invention is not particularly limited, but includes a prepreg lamination molding method, a resin transfer molding method, a resin film infusion method, a hand layup method, a sheet molding compound method, and a filament winding method. , Pultrusion method, etc.

  The resin transfer molding method is a method in which a reinforcing fiber substrate is directly impregnated with a liquid thermosetting resin and cured. Since this method does not go through an intermediate such as a prepreg, it has the potential to reduce molding costs, and can be preferably used for structural materials such as spacecraft, aircraft, railway vehicles, automobiles, and ships.

  The filament winding method is a method in which one to several tens of rovings are aligned, wound around a rotating mold (mandrel) while being impregnated with resin, tensioned to a predetermined thickness, wound at a predetermined angle, and demolded after curing. is there.

  In the pultrusion method, the reinforcing fiber is continuously passed through an impregnation tank filled with a liquid thermosetting resin composition, impregnated with the thermosetting resin composition, and continuously through a squeeze die and a heating die by a tension machine. This is a molding method in which the resin is molded and cured while being drawn. Since this method has an advantage that a fiber reinforced composite material can be continuously formed, it is used for manufacturing reinforced fiber plastics (FRP) such as fishing rods, rods, pipes, sheets, antennas, and building structures.

  The prepreg laminate molding method is a method in which a resin is heated and cured while applying pressure to the shaped product and / or the laminate after shaping and / or laminating the prepreg.

  Among these, the prepreg laminate molding method is preferable because the fiber-reinforced composite material is excellent in rigidity and strength.

  The prepreg of the present invention is obtained by impregnating a fiber base material with the epoxy resin composition of the present invention. Examples of the impregnation method include a wet method and a hot melt method (dry method).

  In the wet method, after immersing the reinforcing fiber in a solution in which the epoxy resin composition is dissolved in a solvent such as methyl ethyl ketone or methanol, the reinforcing fiber is pulled up, and the solvent is evaporated from the reinforcing fiber using an oven or the like. This is a method of impregnating a reinforcing fiber. The hot melt method is a method in which a reinforcing fiber is impregnated directly with an epoxy resin composition whose viscosity is reduced by heating, or a film in which an epoxy resin composition is coated on a release paper is prepared, and then both sides of the reinforcing fiber are prepared. Alternatively, it is a method of impregnating a reinforcing fiber with a resin by overlapping the film from one side and heating and pressing. In particular, since there is no solvent remaining in the prepreg, it is preferable to use a hot melt method.

The amount of reinforcing fiber per unit area of the prepreg is preferably 70 to 200 g / m ² . When the amount of the reinforcing fiber is less than 70 g / m ² , it is necessary to increase the number of laminated layers in order to obtain a predetermined thickness at the time of forming the fiber reinforced composite material, and the laminating work may be complicated. On the other hand, when the amount of reinforcing fibers exceeds 200 g / m ² , the prepreg drapability tends to deteriorate. The fiber mass content is preferably 60 to 90% by mass, more preferably 65 to 85% by mass, and further preferably 70 to 80% by mass. If the fiber mass content is less than 60% by mass, the resin ratio is too high, so that the advantages of the fiber reinforced composite material having excellent specific strength and specific elastic modulus cannot be obtained, and the calorific value when the fiber reinforced composite material is cured. May become too high. Further, when the fiber mass content exceeds 90 mass%, resin impregnation failure occurs, so that the obtained fiber-reinforced composite material may have many voids.

  Here, in the prepreg lamination molding method, as a method of applying heat and pressure, a press molding method, an autoclave molding method, a bagging molding method, a wrapping tape method, an internal pressure molding method, or the like can be appropriately used.

  The autoclave molding method is a method of laminating a prepreg on a tool plate of a predetermined shape, covering with a bagging film, pressurizing and heat-curing while degassing the inside of the laminate, and the fiber orientation can be precisely controlled, Further, since the generation of voids is small, a molded article having excellent mechanical properties and high quality can be obtained. The pressure applied during molding is preferably 0.3 to 1.0 MPa. The molding temperature is preferably in the range of 90 to 200 ° C.

  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 a fiber reinforced composite material is formed, and is a preferable method for producing a rod-like body such as a golf shaft or a fishing rod. More specifically, the prepreg is wound around a mandrel, and a wrapping tape made of a thermoplastic film is wound outside the wound prepreg to apply tension to the prepreg so as to fix the prepreg and apply pressure. . In this method, the resin is heated and cured in an oven, and then the mandrel is extracted to obtain a tubular body. The tension for winding the wrapping tape is preferably 20 to 78N. The molding temperature is preferably in the range of 80 to 200 ° C.

  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. This method is preferably used when molding a complicated shape such as a golf shaft, a bad, a racket such as tennis or badminton. The pressure applied during molding is preferably 0.1 to 2.0 MPa. The molding temperature is preferably in the range of room temperature to 200 ° C, and more preferably in the range of 80 to 180 ° C.

  The fiber reinforced composite material obtained by curing using the epoxy resin composition of the present invention as a matrix resin is preferably used for sports applications, general industrial applications, and aerospace applications. More specifically, in sports applications, it is preferably used for golf shafts, fishing rods, tennis and badminton racket applications, stick applications such as hockey, and ski pole applications. In addition, in general industrial applications, structural materials for moving bodies such as automobiles, bicycles, ships and railway vehicles, drive shafts, leaf springs, windmill blades, pressure vessels, flywheels, paper rollers, roofing materials, cables, and repair reinforcement materials Etc. are preferably used.

  The tubular body made of fiber-reinforced composite material obtained by curing the prepreg of the present invention into a tubular shape can be preferably used for golf shafts, fishing rods and the like.

Hereinafter, the present invention will be described in more detail with reference to examples. Here, Examples 2 to 10, 18, and 19 are examples of the present invention, and Examples 1, 11 to 17 are reference examples. Various physical properties were measured by the following methods. These physical properties were measured in an environment at a temperature of 23 ° C. and a relative humidity of 50% unless otherwise specified.

(1) Preparation of epoxy resin composition In kneader, other components such as block copolymer [E] other than curing agent and curing accelerator are added in a predetermined amount, and the temperature is raised to 150 ° C while kneading. By kneading at 150 ° C. for 1 hour, a transparent viscous liquid was obtained. After the temperature was lowered while kneading to 70 ° C., a predetermined amount of a curing agent and a curing accelerator were added and kneaded to obtain an epoxy resin composition. The compounding ratio of each Example and Comparative Example is as shown in Tables 2-4.

<Epoxy resin ([A])>
Bisphenol A type epoxy resin ("jER (registered trademark)" 1007, epoxy equivalent: 1925, manufactured by Mitsubishi Chemical Corporation, softening point: 128 ° C)
Bisphenol F type epoxy resin (“jER (registered trademark)” 4007P, epoxy equivalent: 2270, manufactured by Mitsubishi Chemical Corporation, softening point: 108 ° C.)
Bisphenol F type epoxy resin (“jER (registered trademark)” 4010P, epoxy equivalent: 4400, manufactured by Mitsubishi Chemical Corporation, softening point: 135 ° C.)
<Epoxy resin ([B])>
Tetraglycidyl diaminodiphenyl methane (“Sumiepoxy (registered trademark)” ELM434, manufactured by Sumitomo Chemical Co., Ltd., epoxy equivalent: 125)
Triglycidyl-p-aminophenol ("jER (registered trademark)" jER630, epoxy equivalent: 98, manufactured by Mitsubishi Chemical Corporation)
Triglycidyl-p-aminophenol (“Araldide (registered trademark)” MY0500, epoxy equivalent: 110, manufactured by Heitzmann Advanced Material Co., Ltd.)
-3,3'-tetraglycidyl diamino diphenyl ether (TG3DDE, epoxy equivalent: 122, manufactured by Toray Fine Chemical Co., Ltd.).

<Epoxy resin ([C])>
-Bisphenol F type epoxy resin ("Epiclon (registered trademark)" 830, epoxy equivalent: 170, manufactured by DIC Corporation).

<Curing agent ([D])>
Dicyandiamide (curing agent, DICY7, manufactured by Mitsubishi Chemical Corporation).

<Block copolymer [E]>
SBM copolymer (“Nanostrength®” E40: S is styrene (Tg: about 90 ° C.), B is 1,4-butadiene (Tg: about −90 ° C.), M is methacrylic acid Methyl (Tg: about 130 ° C.) manufactured by Arkema Co., Ltd.
MBM copolymer (“Nanostrength (registered trademark)” M22N: B is butyl acrylate (Tg: about −50 ° C.), M is a copolymer of methyl methacrylate and a polar functional group-containing monomer (Tg: About 130 ° C.), manufactured by Arkema Co., Ltd.).

<Other ingredients>
・ Polyfunctional epoxy resin ("jER (registered trademark)" 1031S, epoxy equivalent: 200, manufactured by Mitsubishi Chemical Corporation)
Bisphenol A type epoxy resin (“jER (registered trademark)” 1001, epoxy equivalent: 470, manufactured by Mitsubishi Chemical Corporation, softening point: 64 ° C.)
・ "Vinylec (registered trademark)" PVF-K (polyvinyl formal), manufactured by Chisso Corporation
DCMU99 (3- (3,4-dichlorophenyl) -1,1-dimethylurea, curing accelerator, manufactured by Hodogaya Chemical Co., Ltd.)

(2) Number average molecular weight measurement “HLC (registered trademark)” 8220GPC (manufactured by Tosoh Corporation) as a measuring device, UV-8000 (254 nm) as a detector, and TSK-G4000H (manufactured by Tosoh Corporation) as a column. Using. The epoxy resin was dissolved in THF at a concentration of 0.1 mg / ml, and this was measured at a flow rate of 1.0 ml / min and at a temperature of 40 ° C., and the molecular weight was determined using the retention time of the polystyrene calibration sample. It was calculated in terms of Table 1 shows the number average molecular weight measurement results.

(3) Elastic modulus of cured resin After the defoaming of the epoxy resin composition in vacuum, unless otherwise noted in a mold set to 2 mm thick with a 2 mm thick Teflon (registered trademark) spacer, 130 Curing was performed at a temperature of 90 ° C. for 90 minutes to obtain a cured resin having a thickness of 2 mm. From this cured resin, a test piece having a width of 10 mm and a length of 60 mm was cut out, an Instron universal testing machine (manufactured by Instron) was used, the span was set to 32 mm, the crosshead speed was set to 100 mm / min, and JIS K7171 (1994). In accordance with the above, three-point bending was performed to obtain an elastic modulus. The number of samples was set to n = 5, and the average value was compared.

(4) Measurement of resin toughness value of resin cured product After defoaming the epoxy resin composition in vacuum, it is not particularly refused in a mold set to be 6 mm thick with a 6 mm thick Teflon (registered trademark) spacer. As long as it was cured at a temperature of 130 ° C. for 90 minutes, a cured resin product having a thickness of 6 mm was obtained. This cured resin product was cut into a width of 12.7 mm and a length of 150 mm to obtain a test piece. A test piece having a width of 12.7 mm and a length of 150 mm was cut out from the cured resin, processed according to ASTM D5045 (1999), and measured using an Instron universal tester (Instron). It was. The initial precrack was introduced into the test piece by applying a razor blade cooled to liquid nitrogen temperature to the test piece and applying an impact to the razor with a hammer. Here, the resin toughness value refers to the critical stress strength of deformation mode I (opening type).

(5) Measurement of structural period After the resin cured product obtained in (4) was dyed, it was cut into thin sections and a transmission electron image was obtained under the following conditions using a transmission electron microscope (TEM). As the staining agent, OsO ₄ and RuO ₄ were properly used according to the resin composition so that the morphology was sufficiently contrasted.
Apparatus: H-7100 transmission electron microscope (manufactured by Hitachi, Ltd.)
・ Acceleration voltage: 100 kV
-Magnification: 10,000 times Thereby, the structural period of [A] rich phase, [B] rich phase, and [E] rich phase was observed. Depending on the types and ratios of [A], [B], and [E], the phase separation structure of the cured resin formed a biphasic continuous structure and a sea-island structure, and each was measured as follows.

  In the case of a biphasic continuous structure, three straight lines of a predetermined length are drawn randomly on the micrograph, the intersection of the straight line and the phase interface is extracted, the distance between adjacent intersections is measured, and the number average of these The value was the structure period. The predetermined length is set as follows based on a micrograph. When the structural period is expected to be on the order of 0.01 μm (0.01 μm or more and less than 0.1 μm), a photograph is taken at a magnification of 20,000 times, and a length of 20 mm drawn on the photograph (a length of 1 μm on the sample) In the same manner, when the phase separation structure period is expected to be on the order of 0.1 μm (0.1 μm or more and less than 1 μm), a photograph is taken at a magnification of 2,000 times, and the length is randomly 20 mm on the photograph. When the phase separation structure period is expected to be on the order of 1 μm (1 μm or more and less than 10 μm), a photograph is taken at a magnification of 200 times and a length of 20 mm is randomly selected on the photograph ( 100 μm length) on the sample. If the measured phase separation structure period was out of the expected order, it was measured again at a magnification corresponding to the corresponding order.

  In the case of the sea-island structure, three predetermined areas are selected on the micrograph, and the number average value of the island phase sizes in the area is selected. The size of the island phase refers to the length of the shortest distance line drawn from the phase interface to one phase interface through the island phase. Even when the island phase is an ellipse, an indeterminate shape, or a circle or ellipse of two or more layers, the shortest distance passing through the island phase from the phase interface to one phase interface is used. The predetermined region is set as follows based on a micrograph. When the phase separation structure period is expected to be on the order of 0.01 μm (0.01 μm or more and less than 0.1 μm), a photograph is taken at a magnification of 20,000 times, and a 4 mm square region (on the sample) randomly selected on the photograph In the same way, if the phase separation structure period is expected to be on the order of 0.1 μm (0.1 μm or more and less than 1 μm), the photograph is taken at a magnification of 2,000 times. When the phase separation structure period is expected to be on the order of 1 μm (1 μm or more and less than 10 μm), the photograph is taken at a magnification of 200 times. 4 mm square area (20 μm square area on the sample) selected at random. If the measured phase separation structure period was out of the expected order, it was measured again at a magnification corresponding to the corresponding order.

(6) Preparation of prepreg The epoxy resin composition was applied to a release paper using a reverse roll coater to prepare a resin film. Next, two resin films of carbon fiber “Torayca (registered trademark)” T800SC-24K (manufactured by Toray Industries, Inc., tensile elastic modulus: 294 GPa, tensile strength: 5880 MPa) aligned in one direction in the form of a sheet are formed. The carbon fiber mass per unit area was impregnated with an epoxy resin composition, and a unidirectional prepreg using T800SC having a carbon fiber mass of 125 g / m ² and a fiber mass content of 75 mass% was produced. Further, in the same manner as described above except that T700SC-24K (manufactured by Toray Industries, Inc., tensile elastic modulus: 230 GPa, tensile strength: 4900 MPa) was used as the carbon fiber, the mass of the carbon fiber per unit area was 125 g / m ² , A unidirectional prepreg using T700SC having a fiber mass content of 75% by mass was also produced.

(7) Production of unidirectional laminated board It produced by operation of following (a) and (b).
(A) The unidirectional prepreg prepared in (6) above was laminated in 20 ply with the fiber direction aligned.
(B) The laminated prepreg was covered with a nylon film so that there was no gap. This was cured by heating and pressing at 135 ° C. and an internal pressure of 588 kPa for 2 hours in an autoclave to produce a unidirectional laminate.

(8) Fabrication of tubular body made of fiber reinforced composite material for cylindrical Charpy impact test By the following operations (a) to (e), a T800SC unidirectional prepreg is used, and the fiber direction is 45 ° with respect to the cylindrical axis direction. 3ply is laminated alternately so that the angle is 45 °, and one-way prepreg using T800SC is laminated, 3ply is laminated so that the fiber direction is parallel to the cylindrical axis direction, and the inner diameter is 6.3 mm. A tubular material was made. The mandrel was a stainless steel round bar with a diameter of 6.3 mm and a length of 1000 mm.

  (A) Two sheets were cut into a rectangular shape having a length of 104 mm and a width of 800 mm (so that the fiber axis direction was 45 degrees with respect to the direction of the long side) from the unidirectional prepreg using T800SC produced according to (6) above. . The two prepreg fibers were laminated so that the directions of the fibers crossed each other and shifted by 10 mm (half the mandrel half circumference) in the short side direction.

  (B) The mandrel was wound so that the long side of the rectangular shape of the prepreg bonded to the mandrel subjected to the mold release treatment and the mandrel axial direction were the same direction.

  (C) On top of that, a unidirectional prepreg using T800SC produced according to (6) above was cut into a rectangular shape with a length of 114 mm and a width of 800 mm (the long side direction is the fiber axis direction), and the fiber direction is The mandrel was wound around so that the direction of the mandrel axis was the same.

  (D) Further, a wrapping tape (heat-resistant film tape) was wrapped around the wound product to cover the wound product, and then heat-molded at 130 ° C. for 90 minutes unless otherwise specified. The width of the wrapping tape was 15 mm, the tension was 34 N, the winding pitch (deviation amount at the time of winding) was 2.0 mm, and this was 2 ply wrapping.

(E) Thereafter, the mandrel was extracted, and the wrapping tape was removed to obtain a fiber-reinforced composite material tubular body.
In addition, a tubular body made of fiber reinforced composite material using T700SC was prepared in the same manner as the above operations (a) to (e) except that a unidirectional prepreg using T700SC was used.

(9) Charpy impact test of fiber-reinforced composite material tubular body The fiber-reinforced composite material tubular body obtained in (8) above was cut at 60 mm to prepare a test piece having an inner diameter of 6.3 mm and a length of 60 mm. A Charpy impact test was performed by applying an impact from the side of the tubular body at a weight of 300 kg · cm. From the swing angle, the following formula:
E = WR [(cosβ-cosα) − (cosα′−cosα) (α + β) / (α + α ′)]
E: Absorbed energy (J)
WR: Moment around the rotation axis of the hammer (N · m)
α: Hammer lift angle (°)
α ': Swing angle when the hammer is swung from the lift angle α (°)
β: Hammer swing angle after test specimen breakage (°)
The absorbed energy of impact was calculated according to Note that notches (notches) are not introduced into the test piece. The number of measurements was n = 5, and the average values were compared.

(10) Measuring method of 0 ° bending strength of fiber reinforced composite material As an index of bending strength of the fiber reinforced composite material, 0 ° bending strength of the fiber reinforced composite material of the unidirectional material was measured. The unidirectional laminate was cut out to have a thickness of 2 mm, a width of 15 mm, and a length of 100 mm. Using an Instron universal testing machine (manufactured by Instron), measurement was performed at a crosshead speed of 5.0 mm / min, a span of 80 mm, an indenter diameter of 10 mm, and a fulcrum diameter of 4 mm, and the bending strength was calculated. Moreover, after calculating | requiring real Vf based on the fabric weight of the produced prepreg, the obtained bending strength was converted into Vf60%.

(11) Softening point measurement (ring and ball method)
Measured by ring and ball method JIS-K7234 (2008).

(12) Measurement of glass transition temperature of epoxy component of cured resin product A cured resin product produced by the same method as in (3) above was cut out to a width of 13 mm and a length of 35 mm using a diamond cutter, and the cured resin product was subjected to dynamic viscosity. Using an elasticity measuring device (DMAQ800: manufactured by TA Instruments Inc.), the temperature was raised from 40 ° C. to 250 ° C. at a rate of temperature rise of 5 ° C./min, and the glass transition temperature was measured in a bending mode with a frequency of 1.0 Hz. It was. The onset temperature of the storage elastic modulus at this time was defined as the glass transition temperature. Tables 1 and 2 show the results. However, in the measurement of the glass transition temperature of the cured resin having a phase separation structure, two glass transition temperatures of the cured resin may occur, and the glass transition temperatures shown in Tables 1 and 2 are the lower glass transition temperatures. It is.

Example 1
[A] is 30 parts of jER1007, [B] is 40 parts of MY0500, [C] is 30 parts of Epicron 830, and curing agent [D] is DICY7 with respect to the epoxy groups of all epoxy resin components. An epoxy resin composition was prepared using an amount of 0.9 equivalent and 2 parts of DCMU99 as a curing accelerator. The resulting epoxy resin composition had a good viscosity at 80 ° C. The resulting epoxy resin composition was heated at 2.5 ° C./min and cured at 130 ° C. for 90 minutes. The obtained cured resin formed a fine phase separation structure and had good mechanical properties. As a result, the impact resistance of the tubular body made of fiber-reinforced composite material produced using the obtained epoxy resin and carbon fiber T800SC-24K and the 0 ° bending strength of the unidirectional laminate were also good.

(Example 2)
An epoxy resin composition was prepared in the same manner as in Example 1 except that 30 parts of jER4007P was used as [A]. The resulting epoxy resin composition had a good viscosity at 80 ° C. The obtained epoxy resin composition was cured under the same conditions as in Example 1. The obtained cured resin formed a fine phase separation structure and improved the elastic modulus as compared with Example 1. As a result, the 0 ° bending strength of the unidirectional laminate produced using the obtained epoxy resin and carbon fiber T800SC-24K was improved as compared with Example 1.

(Example 3)
[A] is 40 parts of jER4007P, [B] is 40 parts of ELM434, [C] is 20 parts of Epicron 830, and the curing agent [D] is DICY7 with respect to the epoxy groups of all epoxy resin components. An epoxy resin composition was prepared using an amount of 0.9 equivalent and 2 parts of DCMU99 as a curing accelerator. The resulting epoxy resin composition had a good viscosity at 80 ° C. The obtained epoxy resin composition was cured under the same conditions as in Example 1. The obtained cured resin formed a fine phase separation structure and had good mechanical properties. As a result, the mechanical properties of the fiber-reinforced composite material produced using the obtained epoxy resin and carbon fiber T800SC-24K were also good.

Example 4
An epoxy resin composition was prepared in the same manner as in Example 3 except that 40 parts of MY0500 was used as [B]. The resulting epoxy resin composition had a good viscosity at 80 ° C. The obtained epoxy resin composition was cured under the same conditions as in Example 1. The obtained cured resin formed a fine phase separation structure, and the resin elastic modulus was improved as compared with Example 3. As a result, the 0 ° bending strength of the unidirectional laminate produced using the obtained epoxy resin and carbon fiber T800SC-24K was also improved as compared with Example 3.

(Example 5)
An epoxy resin composition was prepared in the same manner as in Example 4 except that 40 parts of jER630 was used as [B]. The resulting epoxy resin composition had a good viscosity at 80 ° C. The obtained epoxy resin composition was cured in the same manner as in Example 1. The obtained resin cured product formed a fine phase separation structure, and the resin elastic modulus was improved as compared with Example 4. As a result, the 0 ° bending strength of the unidirectional laminate produced using the obtained epoxy resin and carbon fiber T800SC-24K was also improved as compared with Example 4.

(Example 6)
An epoxy resin composition was prepared in the same manner as in Example 4 except that 40 parts of jER4010P was used as [A]. The resulting epoxy resin composition had a good viscosity at 80 ° C. The obtained epoxy resin composition was cured under the same conditions as in Example 1. The obtained cured resin formed a fine phase separation structure, and the resin toughness value was improved as compared with Example 4. As a result, the impact resistance of the tubular body made of fiber reinforced composite material produced using the obtained epoxy resin and carbon fiber T800SC-24K was improved as compared with Example 4.

(Example 7)
45 parts of jER4007P as [A], 45 parts of MY0500 as [B], 10 parts of Epicron 830 as [C], and DICY7 as curing agent [D] with respect to the epoxy groups of all epoxy resin components, An epoxy resin composition was prepared using an amount of 0.9 equivalent and 2 parts of DCMU99 as a curing accelerator. The resulting epoxy resin composition had a good viscosity at 80 ° C. The obtained epoxy resin composition was cured under the same conditions as in Example 1. The obtained cured resin formed a fine phase separation structure and had a good resin toughness value and elastic modulus. As a result, the impact resistance property and the 0 ° bending strength of the unidirectional laminate were good for the fiber-reinforced composite material tubular body produced using the obtained epoxy resin composition and the prepreg made of T700SC-24K as the carbon fiber. there were.

(Example 8)
A fiber-reinforced composite material was obtained in the same manner as in Example 7 except that T800SC-24K was used as the carbon fiber. The impact resistance characteristics of the obtained fiber-reinforced composite material tubular body and the 0 ° bending strength of the unidirectional laminate were improved as compared with Example 7.

Example 9
30 parts of jER4007P as [A], 50 parts of MY0500 as [B], 20 parts of Epicron 830 as [C], and DICY7 as curing agent [D] with respect to the epoxy groups of all epoxy resin components, An epoxy resin composition was prepared using an amount of 0.9 equivalent and 2 parts of DCMU99 as a curing accelerator. The resulting epoxy resin composition had a good viscosity at 80 ° C. The obtained epoxy resin composition was cured under the same conditions as in Example 1. The obtained cured resin formed a fine phase separation structure and improved the elastic modulus as compared with Example 2. As a result, the 0 ° bending strength of the unidirectional laminate produced using the obtained epoxy resin and carbon fiber T800SC-24K was also improved.

(Example 10)
[A] is 50 parts of jER4007P, [B] is 30 parts of MY0500, [C] is 20 parts of Epicron 830, and the curing agent [D] is DICY7 with respect to the epoxy groups of all epoxy resin components. An epoxy resin composition was prepared using an amount of 0.9 equivalent and 2 parts of DCMU99 as a curing accelerator. The resulting epoxy resin composition had a good viscosity at 80 ° C. The obtained epoxy resin composition was cured under the same conditions as in Example 1. The obtained cured resin formed a fine phase separation structure, and the resin toughness value was improved as compared with Example 9. As a result, the impact resistance of the fiber reinforced composite material tubular body produced using the obtained epoxy resin and carbon fiber T800SC-24K was improved.

(Example 11)
20 parts of jER4007P as [A], 40 parts of jER630 as [B], 40 parts of Epicron 830 as [C], and DICY7 as curing agent [D] with respect to the epoxy groups of all epoxy resin components, An epoxy resin composition was prepared using an amount of 0.9 equivalent and 2 parts of DCMU99 as a curing accelerator. The obtained epoxy resin composition was cured under the same conditions as in Example 1. The obtained cured resin formed a fine phase separation structure and had good mechanical properties. However, since the viscosity at 80 ° C. of the epoxy resin composition was as low as 2 Pa · s, the produced prepreg was slightly cracked. In addition, the impact resistance characteristic of the tubular body made of fiber reinforced composite material produced using the obtained epoxy resin and carbon fiber T800SC-24K and 0 ° bending strength of the unidirectional laminate were good.

(Example 12)
An epoxy resin composition was prepared in the same manner as in Example 11 except that 20 parts of Epicron 830 was used as [C] and 20 parts of jER1031S was used as the other epoxy resin. The obtained epoxy resin composition was cured under the same conditions as in Example 1. The obtained resin cured product formed a fine phase separation structure, and although the elastic modulus was slightly lowered as compared with Example 11, the glass transition temperature was improved. The impact resistance of the tubular body made of fiber reinforced composite material produced using the obtained epoxy resin and carbon fiber T800SC-24K and the 0 ° bending strength of the unidirectional laminate were also good. Furthermore, since the viscosity at 80 ° C. of the obtained epoxy resin composition was 16 Pa · s, the impact resistance characteristics of the fiber-reinforced composite material tubular body and the 0 ° bending strength of the unidirectional laminates were Improved compared to 11.

(Example 13)
An epoxy resin composition was prepared in the same manner as in Example 11 except that 10 parts of polyvinyl formal resin PVF-K, which is a thermoplastic resin, was added as the other component. The resulting epoxy resin composition had a good viscosity at 80 ° C. The obtained epoxy resin composition was cured under the same conditions as in Example 1. The obtained cured resin formed a fine phase separation structure and had good mechanical properties. Furthermore, since the viscosity at 80 ° C. of the obtained epoxy resin composition was an appropriate viscosity of 31 Pa · s, the impact resistance characteristics of the fiber-reinforced composite material tubular body and the 0 ° bending strength of the unidirectional laminate were as follows. Improved compared to 11.

(Example 14)
30 parts of jER1007 as [A], 40 parts of ELM434 as [B], 30 parts of Epicron 830 as [C], and DICY7 as curing agent [D] with respect to the epoxy groups of all epoxy resin components, An epoxy resin composition was prepared using an amount of 0.9 equivalent and 2 parts of DCMU99 as a curing accelerator. The resulting epoxy resin composition had a good viscosity at 80 ° C. The obtained epoxy resin composition was cured under the same conditions as in Example 1. The obtained cured resin formed a fine phase separation structure and had a good resin toughness value and elastic modulus. As a result, the impact resistance property and the 0 ° bending strength of the unidirectional laminate were good for the fiber-reinforced composite material tubular body produced using the obtained epoxy resin composition and the prepreg made of T800SC-24K as the carbon fiber. there were.

(Example 15)
20 parts of jER4007P as [A], 40 parts of jER630 as [B], 40 parts of Epicron 830 as [C], and DICY7 as curing agent [D] with respect to the epoxy groups of all epoxy resin components, An amount of 0.9 equivalent, an epoxy resin composition was prepared using 3 parts of the SBM copolymer as the block copolymer [E] and 2 parts of DCMU99 as the curing accelerator. The resulting epoxy resin composition had a good viscosity at 80 ° C. The obtained epoxy resin composition was cured under the same conditions as in Example 1. The obtained cured resin formed a fine phase separation structure, and the resin toughness value compared with Example 13 was improved. As a result, the impact resistance characteristics of the obtained fiber reinforced composite material tubular body produced using the epoxy resin composition and the prepreg made of T800SC-24K as the carbon fiber were improved as compared with Example 13.

(Example 16)
An epoxy resin composition was prepared in the same manner as in Example 11 except that 3 parts of MBM copolymer was used as the block copolymer [E]. The resulting epoxy resin composition had a good viscosity at 80 ° C. The obtained epoxy resin composition was cured under the same conditions as in Example 1. The obtained cured resin formed a fine phase separation structure, and the resin toughness value compared with Example 13 was improved. As a result, the impact resistance characteristics of the obtained fiber reinforced composite material tubular body produced using the epoxy resin composition and the prepreg made of T800SC-24K as the carbon fiber were improved as compared with Example 13.

(Example 17)
An epoxy resin composition was prepared in the same manner as in Example 11, except that 10 parts of MBM copolymer was used as the block copolymer [E]. The resulting epoxy resin composition had a good viscosity at 80 ° C. The obtained epoxy resin composition was cured under the same conditions as in Example 1. The obtained cured resin formed a fine phase separation structure, and the resin toughness value was greatly improved as compared with Example 16. As a result, the impact resistance characteristics of the fiber-reinforced composite material tubular body produced using the obtained epoxy resin composition and the prepreg made of T800SC-24K as the carbon fiber were improved as compared with Example 16.
(Example 18)
[A] is 40 parts of jER4007P, [B] is 30 parts of TG3DAS, [C] is 30 parts of Epicron 830, and the curing agent [D] is DICY7 with respect to the epoxy groups of all epoxy resin components. An epoxy resin composition was prepared using an amount of 0.9 equivalent and 2 parts of DCMU99 as a curing accelerator. The resulting epoxy resin composition had a good viscosity at 80 ° C. The obtained epoxy resin composition was cured under the same conditions as in Example 1. The obtained cured resin formed a fine phase separation structure and had good mechanical properties. As a result, the impact resistance of the tubular body made of fiber reinforced composite material produced using the obtained epoxy resin and carbon fiber T800SC-24K and the 0 ° bending strength of the unidirectional laminate were good.

(Example 19)
An epoxy resin composition was prepared in the same manner as in Example 3 except that 40 parts of 3,3′-TGDDE was used as [B]. The resulting epoxy resin composition had a good viscosity at 80 ° C. The obtained epoxy resin composition was cured in the same manner as in Example 1. The obtained cured resin formed a fine phase separation structure, and the resin elastic modulus compared with Example 3 was improved. As a result, the 0 ° bending strength of the unidirectional laminate produced using the obtained epoxy resin and carbon fiber T800SC-24K was improved as compared with Example 3.

(Reference Example 1)
40 parts of jER1007 as [A], 20 parts of jER630 as [B], 40 parts of Epicron 830 as [C], and DICY7 as curing agent [D] with respect to the epoxy groups of all epoxy resin components, An epoxy resin composition was prepared using an amount of 0.9 equivalent and 2 parts of DCMU99 as a curing accelerator. The resulting epoxy resin composition had a good viscosity at 80 ° C. The obtained epoxy resin composition was cured under the same conditions as in Example 1. The obtained cured resin formed a fine phase separation structure, but an elastic modulus as high as that obtained in Examples was not obtained. As a result, the 0 ° bending strength of the unidirectional laminate produced using the obtained epoxy resin composition and carbon fiber T800SC-24K was slightly insufficient as compared with the Examples.

(Reference Example 2)
[A] is 20 parts of jER1007, [B] is 60 parts of ELM434, [C] is 20 parts of Epicron 830, and the curing agent [D] is DICY7 with respect to the epoxy groups of all epoxy resin components. An epoxy resin composition was prepared using an amount of 0.9 equivalent and 2 parts of DCMU99 as a curing accelerator. The resulting epoxy resin composition had a good viscosity at 80 ° C. The obtained epoxy resin composition was cured under the same conditions as in Example 1. Although the obtained resin cured product formed a fine phase separation structure, the resin toughness value as high as the resin toughness value obtained in the examples was not obtained. As a result, the impact resistance of the tubular body made of fiber reinforced composite material produced using the obtained epoxy resin composition and carbon fiber T800SC-24K was slightly insufficient as compared with the Examples.

(Reference Example 3)
10 parts of jER4010P as [A], 50 parts of ELM434 as [B], 40 parts of Epicron 830 as [C], and DICY7 as curing agent [D] with respect to the epoxy groups of all epoxy resin components, An epoxy resin composition was prepared using an amount of 0.9 equivalent and 2 parts of DCMU99 as a curing accelerator. The resulting epoxy resin composition had a good viscosity at 80 ° C. The obtained epoxy resin composition was cured under the same conditions as in Example 1. Although the obtained resin cured product formed a fine phase separation structure, the resin toughness value as high as the resin toughness value obtained in the examples was not obtained. As a result, the impact resistance characteristics of the tubular body made of fiber reinforced composite material produced using the obtained epoxy resin and carbon fiber T800SC-24K were slightly insufficient as compared with the Examples.

(Reference Example 4)
[A] is 60 parts of jER1007, [B] is 30 parts of jER630, [C] is 10 parts of Epicron 830, and the curing agent [D] is DICY7 with respect to the epoxy groups of all epoxy resin components. An epoxy resin composition was prepared using an amount of 0.9 equivalent and 2 parts of DCMU99 as a curing accelerator. The resulting epoxy resin composition had a good viscosity at 80 ° C. The obtained epoxy resin composition was cured under the same conditions as in Example 1. The obtained cured resin formed a fine phase separation structure, but an elastic modulus as high as that obtained in Examples was not obtained. As a result, the 0 ° bending strength of the unidirectional laminate produced using the obtained epoxy resin and carbon fiber T800SC-24K was slightly insufficient as compared with the examples.

(Reference Example 5)
20 parts of jER4007P as [A], 30 parts of MY0500 as [B], 50 parts of Epicron 830 as [C], and DICY7 as curing agent [D] with respect to the epoxy groups of all epoxy resin components, An epoxy resin composition was prepared using an amount of 0.9 equivalent and 2 parts of DCMU99 as a curing accelerator. The resulting epoxy resin composition had a good viscosity at 80 ° C. The obtained epoxy resin composition was cured under the same conditions as in Example 1. Although the obtained resin cured product formed a fine phase separation structure, the resin toughness value as high as the resin toughness value obtained in the examples was not obtained. As a result, the impact resistance characteristics of the tubular body made of fiber reinforced composite material produced using the obtained epoxy resin and carbon fiber T800SC-24K were slightly insufficient as compared with the Examples.

(Comparative Example 1)
[A] is 50 parts of jER1007, [B] is 50 parts of ELM434, and DICY7 is the curing agent [D] in an amount that makes 0.9 equivalents of active hydrogen groups to the epoxy groups of all epoxy resin components, promoting curing. An epoxy resin composition was prepared using 2 parts of DCMU99 as an agent. The obtained epoxy resin composition was cured under the same conditions as in Example 1. Since the epoxy resin [C] was not added, the obtained cured resin formed a coarse phase separation structure, and the elastic modulus was insufficient. Furthermore, since the viscosity at 80 ° C. of the epoxy resin composition exceeded 200 Pa · s, voids occurred in the fiber-reinforced composite material. As a result, the mechanical properties of the fiber reinforced composite material were insufficient.

(Comparative Example 2)
[A] is 50 parts of jER1007, [C] is 50 parts of Epicron 830, and DICY7 is used as the curing agent [D] in such an amount that the active hydrogen group becomes 0.9 equivalent to the epoxy groups of all epoxy resin components. An epoxy resin composition was prepared using 2 parts DCMU99 as an accelerator. The obtained epoxy resin composition was cured under the same conditions as in Example 1. Since the epoxy resin [B] was not added, the obtained resin cured product formed a uniform phase separation structure, and the elastic modulus was insufficient. Furthermore, since the viscosity at 80 ° C. of the epoxy resin composition exceeded 200 Pa · s, a slight void was generated in the fiber-reinforced composite material. As a result, the 0 ° bending strength of the unidirectional laminate produced using the obtained epoxy resin and carbon fiber T800SC-24K was insufficient.

(Comparative Example 3)
50 parts ELM434 as [B], 50 parts Epicron 830 as [C], and DICY7 as the curing agent [D], in an amount such that the active hydrogen groups are 0.9 equivalents relative to the epoxy groups of all epoxy resin components. An epoxy resin composition was prepared using 2 parts DCMU99 as an accelerator. The obtained epoxy resin composition was cured under the same conditions as in Example 1. Since the epoxy resin [A] was not added, the obtained cured resin formed a uniform phase separation structure, and the resin toughness value was remarkably insufficient. As a result, the impact resistance of the fiber-reinforced composite material tubular body produced using the obtained epoxy resin and carbon fiber T800SC-24K was insufficient.

(Comparative Example 4)
[A] is 40 parts of jER1007, [B] is 40 parts of ELM434, 20 parts of GAN is the other epoxy resin, and DICY7 is the curing agent [D] with respect to the epoxy groups of all epoxy resin components. An epoxy resin composition was prepared using an amount of 0.9 equivalent and 2 parts of DCMU99 as a curing accelerator. The obtained epoxy resin composition was cured under the same conditions as in Example 1. Since the epoxy resin [C] was not added, the obtained cured resin formed a coarse phase separation structure, and the resin toughness value was remarkably insufficient. As a result, the impact resistance of the fiber-reinforced composite material tubular body produced using the obtained epoxy resin and carbon fiber T800SC-24K was insufficient.
(Comparative Example 5)
40 parts of ELM434 as [B], 20 parts of Epicron 830 as [C], 40 parts of jER1001 as other epoxy resin, and DICY7 as the curing agent [D] are active hydrogen groups relative to the epoxy groups of all epoxy resin components An epoxy resin composition was prepared using an amount of 0.9 equivalent to 2 parts of DCMU99 as a curing accelerator. The obtained epoxy resin composition was cured under the same conditions as in Example 1. Since the bisphenol type epoxy resin [A] having a softening point of 90 ° C. or higher was not added, the obtained cured resin formed a uniform structure, and the resin toughness value was extremely insufficient. As a result, the impact resistance of the fiber-reinforced composite material tubular body produced using the obtained epoxy resin and carbon fiber T800SC-24K was insufficient.

(Comparative Example 6)
20 parts ELM434 as [B], 45 parts Epicron 830 as [C], 35 parts jER4004P as the other epoxy resin, and DICY7 as the curing agent [D] are active hydrogen groups with respect to the epoxy groups of all epoxy resin components An epoxy resin composition was prepared using 0.9 part by weight of 3 parts DCMU99 as a curing accelerator. The obtained epoxy resin composition was cured under the same conditions as in Example 1. Since the obtained cured resin did not use [A], it formed a uniform structure and lacked the elastic modulus and resin toughness value. As a result, the unidirectional laminate produced using the obtained epoxy resin and carbon fiber T800SC-24K lacked the 0 ° bending strength and the impact resistance characteristics of the fiber-reinforced composite material tubular body.

  The epoxy resin composition of the present invention has a high elastic modulus and a high toughness, and further has a low viscosity, and thus enables prepreg molding with a high fiber content. For this reason, the fiber reinforced composite material which has the outstanding impact resistance and intensity | strength can be obtained by combining an epoxy resin composition and a reinforced fiber. For this reason, the obtained fiber reinforced composite material is preferably used for sports applications, general industrial applications, and aircraft applications.

Claims (9)

Below a [A] ~ epoxy resin composition comprising [D], an epoxy resin [A] ~ [C] on 100 parts by weight total epoxy resin component, Shi meet the following blending ratio The cured resin obtained by curing the epoxy resin composition has a phase separation structure having [A] rich phase and [B] rich phase, and the phase separation structure period is 1 nm to 5 μm. An epoxy resin composition.
[A] Bisphenol F type epoxy resin having a softening point of 90 ° C. or higher 30 to 50 parts by mass [B] Trifunctional or higher amine type epoxy resin 30 to 50 parts by mass [C] Bisphenol F type epoxy resin having a number average molecular weight of 450 or less 10 -40 mass parts [D] Hardener (However, the total amount of epoxy resin [A]-[C] does not exceed 100 mass parts.) The epoxy resin composition according to claim 1 , wherein the epoxy resin [B] is a trifunctional aminophenol type epoxy resin. The epoxy resin composition according to claim 1 or 2 , wherein the curing agent [D] is dicyandiamide or a derivative thereof. Further, at least one block copolymer [E] selected from the group consisting of SBM, BM, and MBM (where each block is linked by a covalent bond) Linked to one block via one covalent bond formation and linked to the other block via another covalent bond formation, wherein block M is a polymethylmethacrylate homopolymer or , A block comprising a copolymer containing at least 50% by weight of methyl methacrylate, block B is incompatible with block M, its glass transition temperature is 20 ° C. or lower, and block S is incompatible with blocks B and M And the glass transition temperature of the block B is higher than the glass transition temperature of the block B). Comprising 10 parts by weight, the epoxy resin composition according to any one of claims 1 to 3. The epoxy resin composition of Claim 4 whose block B of the block copolymer in the said block copolymer [E] is poly 1, 4- butadiene or poly (butyl acrylate). Epoxy resin composition obtained by preparing epoxy resins [A] to [C] and curing agent [D], or epoxy resins [A] to [C], curing agent [D], and block copolymer [E] Epoxy resin [A] to [C] or epoxy resin [A] to [C] and block copolymer [E] having a viscosity at 80 ° C. of the product of 0.5 to 200 Pa · s The epoxy resin according to any one of claims 1 to 5 , wherein a resin toughness value of a cured resin obtained by reacting and curing the resin composition with a curing agent [D] is 1.3 MPa · m ^0.5 or more. Composition. A prepreg comprising the epoxy resin composition according to claim 1 and reinforcing fibers. A fiber-reinforced composite material obtained by curing the prepreg according to claim 7 . A fiber-reinforced composite material comprising a cured resin obtained by curing the epoxy resin composition according to claim 1 and reinforcing fibers.