JP2011157491A - Epoxy resin composition for tow prepreg and tow prepreg - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tow prepreg producible of a fiber-reinforced composite material, which has very low self-adhesiveness, excellent unreeling property from a bobbin, excellent process passing property, and very high fracture toughness; and to provide an epoxy resin composition for the tow prepreg. <P>SOLUTION: The epoxy resin composition for the tow prepreg includes a predetermined epoxy resin, a curing agent, a curing accelerator, and a core shell polymer, and has viscosity of 60 Pa s or less at 25°C. A cured product obtained by curing the epoxy resin composition at 135°C for 2 hours has fracture toughness (KIc) of 1.0 MPa m<SP>0.5</SP>or more. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  In particular, the present invention relates to an epoxy resin composition for tow prepreg that is preferably used for the production of a hollow tubular article made of a fiber-reinforced composite material. More specifically, an epoxy resin composition for tow prepreg, which is excellent in unwinding from a bobbin and processability and can obtain a fiber-reinforced composite material having very high fracture toughness, and such an epoxy resin composition. The present invention relates to a tow prepreg and a fiber reinforced composite material.

  Conventionally, fiber-reinforced composite materials made of carbon fiber, glass fiber, and other reinforcing fibers and epoxy resins, phenol resins, and other thermosetting resins are lightweight, yet have mechanical properties such as strength and rigidity, heat resistance, and corrosion resistance. It has been applied to many fields such as aviation / space, automobiles, rail cars, ships, civil engineering and sports equipment. Especially in applications where high performance is required, fiber reinforced composite materials using continuous reinforcing fibers are used, carbon fibers with excellent specific strength and specific elastic modulus are used as reinforcing fibers, and thermosetting is used as a matrix resin. Of these, many epoxy resins are used that are particularly excellent in adhesion to carbon fibers.

  In the production of a fiber-reinforced composite material, a prepreg that is an intermediate base material in which a reinforcing fiber is aligned in one direction or a sheet-like material such as a woven fabric or a nonwoven fabric is impregnated with a thermosetting resin is often used.

  On the other hand, in addition to the sheet-like prepreg, a narrow fiber width called a tow prepreg, a tow prepreg, a yarn prepreg, or a strand prepreg, in which a reinforcing fiber bundle in which thousands to tens of thousands of filaments are arranged in one direction is impregnated with a thermosetting resin. There is an intermediate substrate (hereinafter referred to as a tow prepreg), and this tow prepreg is suitably used particularly when producing a hollow tubular material composed of a fiber-reinforced composite material.

  The tow prepreg is wound around a bobbin once without interposing a release paper or the like after the reinforcing fiber bundle is impregnated with the thermosetting resin in the manufacturing process. Next, the tow prepreg wound around the bobbin is unwound in the manufacturing process of the fiber reinforced composite material. For this reason, in order to prevent the reinforcing fibers from fuzzing during unraveling, it is essential that the tow prepreg has very little self-adhesiveness and excellent drapeability.

  In order to achieve such an object, a method of blending a thermoplastic resin with a thermosetting resin as in Patent Document 1 and a method of blending an epoxy resin with a molecular weight of 5,000 or more as in Patent Document 2 have been proposed. ing. However, these methods not only increase the viscosity of the thermosetting resin and decrease the drapeability of the tow prepreg, but also significantly reduce the impregnation property of the thermosetting resin and generate an unimpregnated part. When a reinforced composite material is used, there are problems such as voids and reduced mechanical properties.

  Further, as disclosed in Patent Document 3, a method for adjusting the viscosity of an epoxy resin at 25 ° C. to a low viscosity of 0.1 to 300 poise has been proposed. In the case of this method, a certain degree of improvement in the unwinding and draping properties of the tow prepreg is recognized. However, since thermosetting resins such as epoxy resins are brittle materials, they are very brittle, so that a high strength expression rate of reinforcing fibers cannot be achieved.

  As a method for increasing the toughness of an epoxy resin, there is a method of blending fine particles made of either a thermoplastic resin and / or a thermosetting resin as disclosed in Patent Document 4.

  However, in the case of fine particles made of a thermosetting resin, the effect of improving toughness is not sufficient because the thermosetting resin itself is a brittle material. Moreover, when using a thermoplastic resin as a raw material, since it is a ductile material, it can be said that the effect of improving toughness is higher than when a thermosetting resin is used as a raw material. However, nylon (including grill amide) and PBT, which are actually used in the examples of Patent Document 4, are difficult to make particles belonging to so-called engineer plastics, especially to a particle size of 1 μm or less. In Patent Document 4, particles having an average particle size of 30 μm are arranged only on the surface of the prepreg. With such a method, it is not possible to increase the toughness to the inside of the reinforcing fiber bundle, and the effect of improving physical properties is insufficient.

  As another means for increasing the toughness of the epoxy resin, there is a method of blending a crosslinked rubber-like polymer as in Patent Documents 5 and 6. The crosslinked rubbery polymer is usually produced by a method of polymerizing in an aqueous medium such as emulsion polymerization, dispersion polymerization and suspension polymerization. Such a production method is advantageous in that so-called ultrafine particles having a particle size of 1 μm or less can be produced.

  However, when a crosslinked rubber-like polymer as described in these patent documents is used for improving toughness, the effect varies significantly depending on the plastic deformation ability of the base epoxy resin, and the effect of improving toughness may not be sufficiently exhibited. is there. In particular, the tow prepreg must emphasize the unraveling property and drapeability as described above, so the viscosity of the matrix resin cannot be increased. Therefore, like the matrix resin of the sheet-like prepreg, a thermoplastic resin or a high molecular weight is required. Technology for improving thermal deformation capability using epoxy resin cannot be applied.

  For the reasons described above, a tow prepreg that is excellent in unwinding from bobbins, processability, and drapeability, and that can obtain a fiber-reinforced composite material having very high fracture toughness, and manufacturing such a tow prepreg. An epoxy resin composition for tow prepreg that can be made has been desired.

Japanese Patent Laid-Open No. 55-19870 JP 58-113226 A Japanese Patent No. 3480769 Japanese Unexamined Patent Publication No. 63-162732 JP-A-2005-248109 JP-A-10-237196

  In view of this conventional background, the present invention has a very low self-adhesiveness, so that it is excellent in unwinding and processability from a bobbin, has an appropriate drape, and has a very high fracture toughness. It is an object to provide a tow prepreg capable of producing a tow prepreg and an epoxy resin composition for tow prepreg capable of producing the tow prepreg.

The present invention employs the following means in order to solve such problems. That is, the present invention is an epoxy resin composition containing at least the following components [A] to [F] and having a viscosity at 25 ° C. of 60 Pa · s or less, and the epoxy resin composition is heated to a temperature of 135 ° C. The tough prepreg epoxy resin composition is characterized in that the fracture toughness (KIc) of the cured product cured for 2 hours is 1 MPa · m ^0.5 or more.
[A] Epoxy resin having 1 or more aromatic rings or cyclohexane rings and 3 to 4 epoxy groups in one molecule, and a viscosity at 25 ° C. of 5 Pa · s or less [B] Two in one molecule Bisphenol F type epoxy resin [D] having an epoxy group [C] having a viscosity of 70 Pa · s or less at 25 ° C. and having an epoxy equivalent in the range of 350 to 700 g / eq and solid at 25 ° C. Dicyandiamide [E] Curing accelerator [F] A core-shell polymer whose core component is a copolymer containing at least styrene and butadiene.

  According to a preferred embodiment of the epoxy resin composition for toe prepreg of the present invention, the shell component of the core-shell polymer as the constituent element [F] contains at least methyl methacrylate and styrene, and further has a functional group that reacts with the epoxy resin. In addition, the core-shell polymer as the constituent element [F] has a volume average particle diameter of 1 to 500 nm.

  Moreover, according to the more preferable aspect of the epoxy resin composition for tow prepregs of this invention, the compounding quantity of component [A] is 5-30 mass parts in 100 mass parts of all the epoxy resins, and component [C ] Is 5 to 20 parts by mass in 100 parts by mass of all epoxy resins.

  The tow prepreg of the present invention is obtained by impregnating the reinforcing fiber bundle composed of 1,000 to 70,000 filaments with the epoxy resin composition for tow prepreg of the present invention. The elastic modulus is a carbon fiber having a range of 180 to 400 GPa, and the volume content of the carbon fiber is 50 to 75%. In a more preferred embodiment, the number of fluffs measured by the fuzzy fluff evaluation method is 20 or less per 1 m.

  The epoxy resin composition for tow prepregs of the present invention has a very low viscosity and excellent impregnation properties for reinforcing fiber bundles, and the cured product has excellent fracture toughness. In addition, the tow prepreg to which the epoxy resin composition for tow prepregs of the present invention is applied is excellent in unwinding from the bobbin and processability, so that the productivity of the fiber reinforced composite material is good and the resistance to external impact is good. Because fiber reinforced composite materials with excellent impact properties can be obtained, they can be used in many fields such as aerospace, automobiles, railway vehicles, ships, civil engineering and sports equipment, and are used especially for fuel cells. It can be suitably used for a high pressure vessel filled with such hydrogen gas.

The epoxy resin composition for tow prepreg of the present invention is composed of at least the following constituent elements [A] to [F].
[A] Epoxy resin having 1 or more aromatic rings or cyclohexane rings and 3 to 4 epoxy groups in one molecule, and a viscosity at 25 ° C. of 5 Pa · s or less [B] Two in one molecule Bisphenol F type epoxy resin [D] having an epoxy group [C] having a viscosity of 70 Pa · s or less at 25 ° C. and having an epoxy equivalent in the range of 350 to 700 g / eq and solid at 25 ° C. Dicyandiamide [E] Curing accelerator [F] Core-shell polymer whose core component is a copolymer containing at least styrene and butadiene One or more aromatic rings in one molecule which is the constituent element [A] of the present invention, and 3 The epoxy resin having ˜4 epoxy groups and a viscosity at 25 ° C. of 5 Pa · s or less is the heat resistance and elastic modulus of the epoxy resin composition for tow prepreg of the present invention. Is added to enhance

  In the case of a polyfunctional epoxy resin having a large number of epoxy groups in the molecule such as component [A], the higher the epoxy group content in the molecule, the higher the crosslinking density in the three-dimensional crosslinked structure after curing. There is an advantage that the glass transition degree becomes high. However, the curing reaction of the curing agent such as epoxy resin and dicyandiamide is an exothermic reaction, and the exothermic amount increases as the content of epoxy groups contained in the composition increases. When the calorific value is increased, when a thick fiber-reinforced composite material is molded, an excessive temperature rise due to heat storage may occur inside the molded body, and the mechanical properties of the obtained fiber-reinforced composite material may be deteriorated. Therefore, the thickness of the fiber reinforced composite material is limited in a range in which an excessive temperature rise does not occur due to heat storage by a curing reaction.

  On the other hand, in the case of a high-pressure vessel such as a hydrogen tank used in a fuel cell, a thick tubular fiber reinforced composite material is required to prevent damage due to an ultra-high internal pressure. In order to reduce the number, it is essential that the number of epoxy groups contained in one molecule is in the range of 3-4. From such a viewpoint, examples of the constituent element [A] include N, N-bis (2,3-epoxypropyl) -4- (2,3-epoxypropoxy) aniline, N, N-bis (2 , 3-epoxypropyl) -4- (2,3-epoxypropoxy) -2-methylaniline, m-N, N-diglycidylaminophenylglycidyl ether, 1,3-bis (N, N-diglycidylaminomethyl) ) Cyclohexane, N, N ′-[1,3-phenylenebis (methylene)] bis [bis (oxiran-2-ylmethyl) amine] and the like, in particular, N, N-bis (2,3-epoxypropyl). ) -4- (2,3-epoxypropoxy) aniline, N, N-bis (2,3-epoxypropyl) -4- (2,3-epoxypropoxy) -2-methylaniline, -N, N-diglycidyl-aminophenyl glycidyl ether can be preferably used.

  If the compounding amount of the component [A] of the present invention is 5 to 30 parts by mass in 100 parts by mass of all epoxy resin components, a cured product having a high glass transition temperature can be obtained, and the epoxy resin The calorific value generated by the curing reaction of the composition is preferably not too high, and more preferably 7 to 25 parts by mass.

  The component [B] of the present invention is blended in order to adjust the viscosity, heat resistance and mechanical properties of the epoxy resin composition for tow prepreg to an appropriate range.

  Examples of such epoxy resins include bisphenol A type epoxy resins (particularly high purity), bisphenol F type epoxy resins, bisphenol type epoxy resins such as bisphenol AD type epoxy resins, N, N- (diglycidyl) aniline, N, Glycidylamine type epoxy resins such as N-bis (2,3-epoxypropyl) -o-toluidine, glycidyl ester type epoxy resins such as diglycidyl phthalate and diglycidyl terephthalate, vinylcyclohexene diepoxide, 3, 4 -Alicyclic epoxy resins such as epoxycyclohexanecarboxylic acid-3,4-epoxycyclohexylmethyl, bis-3,4-epoxycyclohexylmethyl adipate, ethylene glycol diglycidyl ether, propylene glycol Le diglycidyl ether, hexamethylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, and aliphatic epoxy resins such as 1,6-hexanediol diglycidyl ether. In particular, bisphenol A type epoxy resin and bisphenol F type epoxy resin have a good balance of heat resistance, mechanical properties and viscosity, and N, N- (diglycidyl) aniline, N, N-bis (2,3-epoxypropyl). Since -o-toluidine has a low viscosity and is excellent in the effect of improving the elastic modulus of the cured product, it can be suitably used.

  If the compounding quantity of component [B] of this invention is 50-90 mass parts in 100 mass parts of all the epoxy resin components, the raise of the viscosity of the epoxy resin composition for tow prepregs obtained, and this epoxy resin composition Since the fall of the heat resistance of the hardened | cured material which hardened | cured the thing and the mechanical physical property can be suppressed, it is preferable if it is 55-85 mass parts.

  The component [C] of the present invention is blended in order to impart an appropriate plastic deformation capability to the cured product of the epoxy resin composition for tow prepreg. The plastic deformation ability of the cured product obtained by curing the epoxy resin composition affects the crosslinking density of the three-dimensional crosslinked structure constituting the cured product, and the plastic deformation ability increases as the crosslinking density decreases. In order to reduce the crosslinking density, a compound having a large molecular weight and a small content of epoxy groups contained in one molecule is blended. However, if the crosslink density is lowered too much, the heat resistance and mechanical properties of the cured product are lowered. Therefore, in order to balance each physical property, an epoxy resin having an appropriate molecular weight and the number of epoxy groups is blended.

  Usually, the relationship between the molecular weight and the number of epoxy groups is represented by epoxy equivalent. Here, the epoxy equivalent is a value obtained by dividing the molecular weight by the number of epoxy groups contained in one molecule, and is a molecular weight per one epoxy group. Epoxy equivalent is measured according to JIS K7236 (2001). Specifically, it can be determined by adding a tetraethylammonium bromide acetic acid solution to a solution in which a predetermined amount of epoxy resin and chloroform are mixed and dissolved, and titrating with a perchloric acid acetic acid solution.

The epoxy equivalent of the component [C] of the present invention is essential to be in the range of 350 to 700 g / eq, preferably 400 to 600 g in order to balance the plastic deformation ability and heat resistance, mechanical properties and viscosity. / Eq, more preferably in the range of 450 to 550 g / eq. As described above, when the epoxy equivalent is smaller than 350 g / eq, the crosslinking density is not lowered, and the effect of improving the plastic deformation ability cannot be obtained. Moreover, when an epoxy equivalent is larger than 700 g / eq, a crosslinking density falls and the heat resistance of a hardened | cured material and a mechanical characteristic, especially an elasticity modulus fall large.
Usually, a bisphenol type epoxy resin having an epoxy equivalent in the above-mentioned range is solid at a temperature of 25 ° C. alone. Here, solid means a state in which the storage elastic modulus G ′ is larger than the loss elastic modulus G ″ and the glass transition temperature of the component alone is higher than 25 ° C. in the viscoelastic property. The intermediate point temperature determined by the DSC method according to JIS K7121 (1987).

  As a bisphenol type epoxy resin having an epoxy equivalent in such a range, a bisphenol A type epoxy resin and a bisphenol F type epoxy resin are commercially available. However, the skeleton of the bisphenol A type epoxy resin has a so-called propane structure in which two methyl groups are bonded to a carbon atom between two benzene rings, and the methyl group suppresses the flexibility of the skeleton. However, since the bisphenol F type epoxy resin does not have the methyl group and the hydrogen atom is bonded to it, the bisphenol F type epoxy resin has the effect of improving the plastic deformation capacity because it has a flexible skeleton. large.

  The compounding amount of the constituent element [C] of the present invention is that a range of 5 to 20 parts by mass in 100 parts by mass of all epoxy resin components imparts an appropriate plastic deformability to the obtained epoxy resin composition for tow prepreg, And since it can reduce a heat resistant fall and a raise of a viscosity, it is preferable, and if it is 7-15 mass parts, it is still more preferable.

  Dicyandiamide, component [D] of the present invention, is a thermally activated latent curing agent, impregnated with a resin compounding process stability at room temperature, storage stability at room temperature, or an epoxy resin composition for reinforcing fibers. It is excellent in stability against the heat history received in the process. Here, the thermally activated latent curing agent is in a low activity state below a predetermined temperature, but undergoes a certain heat history to cause a phase change or a chemical change to change into a high activity state. Means nature.

  Dicyandiamide is a particulate curing agent and does not dissolve in the epoxy resin component at a temperature of 25 ° C., but is dispersed in the epoxy resin component in the form of particles, so that it contacts the epoxy group in each epoxy resin component. Since it has a small area, it exhibits little reactivity and is usually dissolved in an epoxy resin when heated to 180 ° C. or higher and has a characteristic of reacting with an epoxy group.

  The blending amount of dicyandiamide, which is the constituent element [D] of the present invention, is set so that the storage stability of the obtained epoxy resin composition for tow prepreg, the calorific value at the time of curing, the heat resistance of the cured product, and the like are in an appropriate range The amount is preferably in the range of 1 to 10 parts by weight, more preferably in the range of 2 to 8 parts by weight, based on 100 parts by weight of all the epoxy resin components including the constituent elements [A] to [C]. By setting the blending amount of the component [D] within such a range, a good cured product can be obtained without causing deterioration of heat resistance and mechanical properties due to insufficient curing or excessive reaction heat generation.

  The curing accelerator which is the constituent element [E] of the present invention is used for enhancing the curing activity of the dicyandiamide which is the constituent element [D]. As the curing accelerator, for example, tertiary amine, Lewis acid complex, onium salt, imidazole, phenol compound and the like can be used alone or in combination, and in particular, 3-phenyl-1,1-dimethylurea, 3- (3,4-dichlorophenyl) -1,1-dimethylurea (DCMU), 3- (3-chloro-4-methylphenyl) -1,1-dimethylurea, 4,4′-methylenebis (diphenyldimethylurea), A urea derivative such as 2,4-toluenebis (3,3-dimethylurea) or an imidazole derivative can be suitably used in combination as a curing accelerator. Among them, 3-phenyl-1,1-dimethylurea, 3- (3,4-dichlorophenyl) -1,1-dimethylurea can be most preferably used. Such a curing accelerator, when dicyandiamide alone needs a temperature of 170 to 180 ° C. for curing, can be cured at 80 to 150 ° C. by using it together with dicyandiamide.

  The amount of the constituent element [E] is appropriately adjusted according to the type of the curing accelerator to be used. Usually, if it is the range of 0.1-10 mass parts with respect to 100 mass parts of all the epoxy resin components containing structural element [A]-[C], a curing temperature can be adjusted optimally and it is preferable.

  The constituent element [E] of the present invention may be solid or liquid, but is in the form of solid particles and hardly dissolves in the epoxy resin component at a temperature of 25 ° C. and remains in the form of particles. The property that is dispersed in the epoxy resin component is more stable in the resin preparation process, storage stability at room temperature, or stability against the heat history received in the process of impregnating the reinforcing fiber with the epoxy resin composition. It is preferable because it improves.

  The core-shell polymer, which is the constituent element [F] of the present invention, is a graft polymerization of a shell component polymer different from the core component on the surface of a particulate core component mainly composed of a crosslinked rubbery polymer or elastomer. A part or the whole of the surface of the particulate core component is coated with a shell component.

  As a core component constituting the core-shell polymer, a polymer polymerized from one or more selected from vinyl monomers, conjugated diene monomers, acrylic acid and / or methacrylic acid ester monomers, or a silicone resin may be used. However, a crosslinked rubber-like polymer composed of an aromatic vinyl monomer and a conjugated diene monomer, especially styrene and butadiene, can be preferably used because of its high toughness improving effect.

  The shell component that constitutes the core-shell polymer is preferably graft-polymerized to the above-described core component, and is preferably chemically bonded to the polymer that constitutes the core component. As a component constituting such a shell component, for example, a polymer polymerized from one or more selected from (meth) acrylic acid esters, aromatic vinyl compounds and the like can be used. When a crosslinked rubber-like polymer composed of styrene and butadiene is used as the core component, a mixture of methyl methacrylate as a (meth) acrylic ester and styrene as an aromatic vinyl compound can be suitably used.

  Moreover, in order to stabilize a dispersion state, it is preferable that the functional group which reacts with the epoxy resin composition for tow prepregs of this invention is introduce | transduced into this shell component. Examples of such functional groups include a hydroxyl group, a carboxyl group, and an epoxy group, and among them, an epoxy group is preferable. As a method for introducing an epoxy group, there is a method in which, for example, 2,3-epoxypropyl methacrylate is used in combination with the above shell component and graft polymerization is performed on the core component.

  The core-shell polymer that can be applied to the epoxy resin composition for tow prepreg of the present invention is not particularly limited as long as it is described above, and those manufactured by a known method can be used. However, the core-shell polymer is usually handled as a powder by pulverizing what is taken out as a lump, and the powder-like core-shell polymer is often dispersed again in the epoxy resin. It is difficult to disperse stably. Therefore, it is preferable that the core-shell polymer can be handled in the form of a masterbatch that is finally dispersed in the epoxy resin without being taken out in a lump from the production process of the core-shell polymer. For example, JP-A-2004-315572 Obtained by obtaining a suspension in which the core-shell polymer is dispersed by polymerizing by the method described in the publication, that is, by polymerizing the core-shell polymer in an aqueous medium represented by emulsion polymerization, dispersion polymerization, and suspension polymerization. After mixing the suspension with water and an organic solvent having partial solubility, for example, an ether solvent such as acetone or methyl ethyl ketone, the mixture is brought into contact with a water-soluble electrolyte such as sodium chloride or potassium chloride. Phase separation is performed, and an epoxy resin is appropriately mixed with the core-shell polymer-dispersed organic solvent obtained by separating and removing the aqueous layer. And a method for the solvent is evaporated off can be used. As the core-shell polymer-dispersed epoxy masterbatch produced by the production method, “Kane Ace (registered trademark)” commercially available from Kaneka Corporation can be suitably used.

  When applying a core-shell polymer to the epoxy resin composition for tow prepreg of the present invention, the core-shell polymer preferably has an average particle size of 1 to 500 nm in terms of volume average particle size, and more preferably 3 to 300 nm. The volume average particle diameter can be measured using a nanotrack particle size distribution analyzer (manufactured by Nikkiso Co., Ltd.). When the volume average particle size of the core-shell polymer used in the present invention is 1 nm or less, it is difficult to produce or becomes very expensive and cannot be used substantially. When the volume average particle size is 500 nm or more, In the step of impregnating the epoxy resin composition for tow prepreg in the prepreg manufacturing process, it is not preferable because it may be separated by reinforcing fibers and the dispersion state in the tow prepreg may become uneven.

  In this invention, it is preferable that 0.5-15 mass parts is mix | blended with 100 mass parts of all the epoxy resin components, and, as for the compounding quantity of component [F], if it is 1-10 mass parts, it is more preferable. If the blending amount is 0.5 parts by mass or more, the fracture toughness required for the fiber-reinforced composite material after molding can be easily obtained, and if the blending amount is 15 parts by mass or less, the obtained tow prepreg is obtained. Since the viscosity of the epoxy resin composition is suppressed from being increased and the reinforcing fiber can be impregnated without difficulty, it is more suitable for tow prepreg.

  The epoxy resin composition for tow prepreg of the present invention is appropriately blended with a monoepoxy compound having only one epoxy group in one molecule within a range that does not significantly reduce the heat resistance and mechanical properties of the cured product. can do.

  Further, the epoxy resin composition for toe prepreg of the present invention includes a plasticizer within a range in which the physical properties of a cured product obtained by heat curing, and thus a fiber reinforced composite material composed of the cured product and reinforcing fibers are not significantly reduced. , Dyes, organic pigments and inorganic fillers, polymer compounds, antioxidants, ultraviolet absorbers, coupling agents, surfactants, and the like can be appropriately blended.

  The epoxy resin composition for tow prepreg of the present invention can be produced by various known methods. For example, there is a method of kneading each component with a kneader. Moreover, you may knead | mix using a biaxial extruder. The dicyandiamide, which is the constituent element [D] of the present invention, is dispersed in each component in a solid state. However, when all the components are kneaded at once, the dicyandiamide may aggregate to cause poor dispersion. A poorly dispersed epoxy resin composition is not preferred because it causes uneven physical properties in the cured product or poor curing. Therefore, it is preferable that dicyandiamide is used as a master batch by using a part of the constituent elements, preliminarily kneading with three rolls.

If the epoxy resin composition for tow prepreg of the present invention is in an uncured state, the blending ratio of each component is infrared absorption analysis (abbreviation: IR), hydrogen-nuclear magnetic resonance (abbreviation: ¹ H-NMR), It can be identified by combining analytical methods such as carbon-13 nuclear magnetic resonance (abbreviation: ¹³ C-NMR), gas chromatography-mass spectrometry (abbreviation: GC-MS), high performance liquid chromatography (abbreviation: HPLC), etc. . For example, the epoxy resin composition for tow prepreg of the present invention is dissolved in water, alcohols, acetonitrile, dichloromethane, trifluoroacetic acid alone or in a mixed solvent, impurities are filtered, and the supernatant is separated by HPLC. For example, a method of measuring the obtained product by IR can be used. Moreover, the component mix | blended with the resin composition by the said method can be identified, and the epoxy equivalent of the mix | blended epoxy resin component can also be calculated from information, such as the obtained molecular weight and the number of epoxy groups. it can.

  The epoxy resin composition for tow prepreg according to the present invention suppresses the occurrence of fluff in the process from unwinding the tow prepreg using the epoxy resin composition from the bobbin and molding the fiber reinforced composite material. For this reason, it is essential that the viscosity at a temperature of 25 ° C. is 60 Pa · s or less, preferably 50 Pa · s or less, and more preferably 40 Pa · s or less. In addition, the viscosity measurement uses a dynamic viscoelastic device ARES-2KFRTN1-FCO-STD (manufactured by TA Instruments Inc.), a 50 mm diameter flat plate for the upper measurement jig, and a flat bottom cup for the lower measurement jig. The epoxy resin composition was set so that the distance between the upper and lower jigs was 1 mm, and then measured in the torsion mode (measurement frequency: 0.5 Hz). Further, the time from the resin setting to the measurement of the viscosity at a predetermined temperature was within 15 minutes. When the viscosity of the epoxy resin composition at a temperature of 25 ° C. is higher than 60 Pa · s, in the production of tow prepreg, the epoxy resin composition cannot be completely impregnated in the reinforcing fiber, and an unimpregnated part is generated. The tow prepreg produced is unwound from the bobbin, and fluff is generated in the process of manufacturing the fiber-reinforced composite material. The lower limit of the viscosity at a temperature of 25 ° C. of the epoxy resin composition for tow prepreg of the present invention is not particularly limited. Generation of fluff can be suppressed.

  In order to set the viscosity of the epoxy resin composition of the present invention at a temperature of 25 ° C. to 60 Pa · s or less, the constituent elements [A] to [C] used in the present invention are blended in an appropriate range. In particular, since the component [C] has a great influence on the increase in viscosity, the amount of the component [C] is preferably 5 to 20 parts by mass in 100 parts by mass of all epoxy resin components as described above. More preferably, it is 7-15 mass parts in 100 mass parts of all the epoxy resin components. The lower limit of the viscosity at 25 ° C. of the epoxy resin composition for tow prepreg of the present invention is not particularly limited, and the lower the viscosity, the better the impregnation property of the reinforcing fibers, the unwinding property from the bobbin, and the process passability. It is preferable for matrix resin for tow prepreg use.

  The epoxy resin composition for tow prepregs according to the present invention obtains a cured product by causing a crosslinking reaction to proceed by heating at an arbitrary temperature of 80 to 180 ° C. for an arbitrary time in the range of 0.5 to 10 hours. Can do. The heating condition may be one stage or may be a multistage condition in which a plurality of heating conditions are combined. In particular, assuming a high-pressure vessel filled with hydrogen gas or the like used for fuel cells, heating is performed at an arbitrary temperature in the range of 80 to 150 ° C. and at an arbitrary time in the range of 0.5 to 5 hours. By curing, desired physical properties of the cured product can be obtained.

The glass transition temperature of the cured product obtained by heat-curing the epoxy resin composition for tow prepreg of the present invention at 135 ° C. for 2 hours is preferably 110 ° C. or higher, and more preferably 130 ° C. or higher. Here, the glass transition temperature is the midpoint temperature obtained by the DSC method according to JIS K7121 (1987). A differential scanning calorimeter DSC Q2000 (manufactured by TA Instruments Inc.) was used as a measuring device, and measurement was performed at a temperature rising rate of 40 ° C./min in a nitrogen gas atmosphere. When the glass transition temperature is 110 ° C. or higher, the fiber reinforced composite material to which the epoxy resin composition is applied, such as a pressure vessel, causes distortion and deformation that occur in the fiber reinforced composite material. It is preferable because a fiber reinforced composite material excellent in environmental resistance can be obtained because the deterioration of mechanical properties can be suppressed. Although the upper limit of the glass transition temperature is not particularly limited, in general, a cured product of an epoxy resin composition starts thermal decomposition at around 240 ° C., so that there is a possibility that a remarkable decrease in mechanical properties occurs at 230 ° C. or higher. The fracture toughness (critical stress intensity factor in mode I: KIc) at 25 ° C. of a cured product obtained by heat-curing the epoxy resin composition for tow prepreg of the present invention at a temperature of 135 ° C. for 2 hours is 1 MPa / m. It is preferably ^0.5 or more, and more preferably 1.3 MPa / m ^0.5 or more. By setting the KIc at a temperature of 25 ° C. to 1 MPa / m ^0.5 or more, it is possible to suppress deterioration in mechanical properties and damage due to fatigue generated by repeatedly using a fiber-reinforced composite material to which the epoxy resin composition is applied. A fiber-reinforced composite material having excellent fatigue characteristics can be obtained. There is no restriction | limiting in particular in the upper limit of KIc in the temperature of 25 degreeC, The fatigue characteristic of the fiber reinforced composite material to which this epoxy resin composition is applied improves, so that this value is large.

  A preferred tow prepreg using the tow prepreg epoxy resin composition of the present invention is a reinforcing fiber comprising the tow prepreg epoxy resin composition comprising 1,000 to 70,000 filaments having a diameter of 3 to 100 μm. The bundle is impregnated.

  Examples of the reinforcing fiber used in the tow prepreg of the present invention include carbon fiber, silicon carbide fiber, glass fiber, and aramid fiber. Particularly, the fiber-reinforced composite material having light weight and high performance and excellent mechanical properties is obtained. Therefore, carbon fiber is preferably used.

  Specific examples of carbon fibers that are preferably used as such reinforcing fibers include acrylic, pitch, and rayon carbon fibers, and acrylic carbon fibers having high tensile strength are particularly preferably used.

  Such an acrylic carbon fiber can be produced, for example, through the following steps. A spinning dope containing polyacrylonitrile obtained from a monomer containing acrylonitrile as a main component is spun by a wet spinning method, a dry wet spinning method, a dry spinning method, or a melt spinning method. The spun coagulated yarn can be made into a precursor through a spinning process, and then carbon fiber can be obtained through processes such as flame resistance and carbonization.

  As the form of carbon fiber, twisted yarn, untwisted yarn, untwisted yarn, etc. can be used, but in the case of twisted yarn, the composition of the filaments constituting the reinforcing fiber bundle is not parallel, so the dynamics of the fiber reinforced composite material An untwisted yarn or a non-twisted yarn having a good balance between formability and strength properties of the fiber-reinforced composite material is preferably used because it causes a decrease in properties.

  When carbon fiber is used as the reinforcing fiber, it is composed of 1,000 to 70,000 filaments, and the fineness is preferably in the range of 400 to 5,000 tex, more preferably composed of 2,000 to 60,000 filaments. The fineness is 800 to 4,000 tex. Here, the fineness refers to a weight per 1000 m of fiber bundle (hereinafter referred to as tex). By setting the number of carbon fiber filaments and the fineness in such a range, a tow prepreg having a desired drape property and less generation of fluff during the process passage can be obtained.

  Such carbon fibers preferably have a tensile modulus in the range of 180 to 400 GPa. If the elastic modulus is lower than this range, the resulting fiber-reinforced composite material may have insufficient rigidity and insufficient weight reduction. Conversely, if the elastic modulus is higher than this range, the strength of the carbon fiber generally decreases. Tend. A more preferable elastic modulus is in the range of 200 to 370 GPa, and more preferably in the range of 220 to 350 GPa. Here, the tensile elastic modulus of the carbon fiber is a value measured according to JIS R7601-2006.

  The tow prepreg of the present invention can be produced by various known methods. That is, the epoxy resin composition for tow prepreg is dissolved in an organic solvent such as methyl ethyl ketone or methanol to lower the viscosity, impregnated while immersing the reinforcing fiber bundle, and then the organic solvent is evaporated using an oven or the like. Wet method for prepreg, or filament winding method in which the epoxy resin composition for tow prepreg is reduced in viscosity by heating without using an organic solvent, and impregnated while dipping a reinforcing fiber bundle, and reduced in viscosity by heating. The epoxy resin composition can be formed into a film on a roll or release paper, then transferred to one or both sides of a reinforcing fiber bundle, and then manufactured by a hot melt method in which it is impregnated by pressing through a bending roll or a pressure roll. , There is virtually no organic solvent remaining in the tow prepreg. Since the prepreg can be produced, it is possible to hot melt method is preferably used.

  The tow prepreg of the present invention preferably has a reinforcing fiber volume content (Vf) of 50 to 75%, more preferably 53 to 72%. If the volume content is less than this range, the resulting fiber-reinforced composite material becomes heavy, and the strength tends to decrease due to the influence of stress concentration. Further, if the volume content of the reinforcing fiber is larger than the above range, a defect portion such as an unimpregnated portion or a void is very often generated inside the obtained fiber-reinforced composite material, which may cause deterioration in physical properties. .

  In addition, the tow prepreg of the present invention is supplied to a mandrel through a plurality of rolls arranged in the process after the tow prepreg wound on the bobbin is unwound in the manufacturing process of the fiber reinforced composite material. The Therefore, it is necessary that the reinforcing fiber does not fluff during unwinding and passing through the process.

  In the tow prepreg of the present invention, the number of fluffs is preferably 20 or less per 1 m of tow prepreg, more preferably 15 solids or less. By setting the number of fluffs to 20 solids or less per meter, it is preferable because a fiber-reinforced composite material having high quality and desired mechanical properties can be obtained. There is no particular limitation on the lower limit of the number of rubbing hairs, and 0 is most preferable. Here, the number of fluffs can be determined by the following method.

  That is, the bobbin around which the tow prepreg is wound is left in a temperature control room controlled at a temperature of 23 ± 5 ° C. and a relative humidity of 60 ± 20% for 30 minutes or more. Next, the bobbin around which the tow prepreg is wound is installed on the creel of the rubbing fluff device in the temperature control chamber. The tow prepreg is pulled out from the bobbin and passed through a fuzzing fluff device to produce a yarn path. The tow prepreg drawn out from the bobbin is bent at an arbitrary angle through a stainless steel free-rotating free guide bar whose surface is first hard chromium-plated and mirror-finished and has a diameter of 20 mm.

Next, the surface is hard chrome plated and passed through a stainless steel fixed guide bar 1 having a diameter of 20 mm, which is not a mirror finish. At this time, the tow prepreg is set to be bent at an angle of 100 degrees from the advancing direction, so that sufficient friction is applied to the tow prepreg and a fuzzed fluff is likely to occur. The tow prepreg that has passed through the fixed guide bar 1 is bent at an arbitrary angle by passing through a fixed guide bar 2 made of the same material as that of the fixed guide bar 1, passes through a fluff counter, and is wound around a bobbin again. The fluff counter is for detecting the number of fluff by a phototransistor while irradiating a tow prepreg running with lamp light and condensing the irradiated light with a lens. As detection accuracy, fluff having a length of 2 mm or more and a carbon fiber single fiber diameter of 3 microns or more can be detected. The running speed of the tow prepreg is adjusted to 7.5 m / min, the unwinding tension when the tow prepreg is unwound from the bobbin is adjusted to 0.3 to 0.5 kgf / line, and the running is started. After confirming that the fluff is stable, the fluff counter is operated, and the evaluation of the rubbing fluff in the running state is repeated three times for 1 minute for each sample. The number of rubbing fluff X [pieces / m] is calculated from the following formula (1), where the number of rubbing fluff counted in 1 minute is X1, X2, and X3.
Formula (1): X = (X1 + X2 + X3) /22.5.

  The tow prepreg of the present invention can be made into a fiber-reinforced composite material by various methods conventionally known. For example, a hollow tubular fiber-reinforced composite material can be obtained by winding the tow prepreg by a tape winding method at a predetermined angle with respect to the axis of the core material, and then heating and curing in an oven. You may wind the heat-shrinkable tape around the surface of what was wound around the core material when making it harden | cure. When a heat-shrinkable tape is wound around the surface of a core material, the tape is shrunk during curing, pressure is applied, and the surface quality of the resulting hollow tubular fiber-reinforced composite material is improved and generated internally. Voids can be suppressed.

  As another method for producing a fiber-reinforced composite material, the tow prepreg is laminated on a rigid tool by a tape placement method, and then sealed with a flexible film, and then the rigid tool and the flexible film are used. A fiber-reinforced composite material having an arbitrary shape can be obtained by suctioning with a vacuum pump and degassing, placing in an autoclave, heating and pressurizing.

  Here, as the material of the rigid tool, various existing materials such as metals such as steel and aluminum, fiber reinforced plastic (FRP), wood, and plaster are used. Nylon, fluorine resin, silicone resin, or the like is used as the material for the flexible film.

  Since the fiber reinforced composite material manufactured using the prepreg of the present invention has excellent impact resistance against external impacts, it is used in many fields such as aerospace, automobiles, railway vehicles, ships, civil engineering and sports equipment. In particular, it can be suitably used for a high pressure vessel filled with hydrogen gas or the like used for a fuel cell.

  Hereinafter, the present invention will be described more specifically with reference to examples. The unit “part” of the composition ratio means part by mass unless otherwise specified.

<Measurement of viscosity of epoxy resin and epoxy resin composition>
The viscosity of the epoxy resin used in each example and comparative example, and the epoxy resin composition for tow prepreg obtained in each example and comparative example was determined by the dynamic viscoelastic device ARES-2KFRTN1-FCO-STD (TEA An epoxy resin composition obtained by using a flat plate with a diameter of 50 mm for the upper measurement jig and a cup with a flat plate bottom for the lower measurement jig, and having a distance between the upper and lower jigs of 1 mm. Was set and measured in torsion mode (measurement frequency: 0.5 Hz). Further, the time from the resin setting to the measurement of the viscosity at a predetermined temperature was within 15 minutes.

<Measurement method of fracture toughness (KIc) of cured resin>
After injecting the epoxy resin composition for tow prepreg obtained in each Example and Comparative Example into a predetermined mold and raising the temperature from room temperature to 135 ° C. in a hot air oven by 1.5 ° C. per minute The epoxy resin composition was cured by holding at 135 ° C. for 2 hours. Next, the temperature was lowered from 135 ° C. to room temperature at a rate of 2.5 ° C. per minute and removed from the mold to produce a 6 mm thick resin cured plate. The obtained cured resin plate was processed into the test piece shape described in ASTM D5045-99, and then a KIc test was performed according to ASTM D5045-99. The number of samples was 5.

<Measurement of glass transition temperature>
Small pieces (5 to 10 mg) were collected from the obtained cured resin plate, and the midpoint glass transition temperature (T _mg ) was measured according to JIS K7121 (1987). For the measurement, a differential scanning calorimeter DSC Q2000 (manufactured by TA Instruments Inc.) was used, and measurement was performed at a heating rate of 40 ° C./min in a nitrogen gas atmosphere. The number of samples was 2.

<Production of toe prepreg>
Reinforced fiber bundles were impregnated with the epoxy resin composition for tow prepreg obtained in each Example and Comparative Example by a hot melt method according to the following method to obtain a tow prepreg.

  Specifically, it is equipped with a creel that sends out reinforcing fibers, a widening bar that opens the bundle of reinforcing fibers, a preheater, a grooved kiss roll impregnated with an epoxy resin composition, a drawing (impregnation) roll, a take-up roll, and a winder for winding. The reinforcing fiber bundle is passed through the tow prepreg manufacturing equipment to make a yarn path. The epoxy resin composition is separately adjusted to a temperature of 30 ° C. with a hot air oven and supplied to the grooved kiss roll with a diaphragm tube pump. A scraping blade is installed in the kiss roll portion, and the Vf (volume content of reinforcing fibers) of the tow prepreg obtained by adjusting the cap of the kiss roll and the blade is adjusted. The reinforcing fiber bundle sent out from the bobbin is heated through a preheater adjusted to a temperature of 140 ° C., and then passes through the groove portion of the kiss roll to which the epoxy resin composition is supplied. A composition is provided. Next, the epoxy resin composition is impregnated into the reinforcing fiber bundle by passing through a squeeze roll to which hot air having a temperature of 80 ° C. is applied. Finally, after passing through the take-up roll, it was wound up with a winder to obtain a tow prepreg bobbin.

  The line speed when producing the tow prepreg was 10 m / min, and the winding line tension was 3200 kgf.

<Vf measurement of toe prepreg>
1 m was taken from the tow prepregs obtained in each Example and Comparative Example, and the weight was measured. The weight of the reinforcing fiber used (a value obtained by dividing the fineness by 1000) is subtracted from the weight per 1 m of the obtained tow prepreg to calculate the weight of the resin composition. The weight of the reinforcing fiber is divided by the density of the reinforcing fiber and converted into a volume. Similarly, the weight of the resin composition calculated is divided by the density of the resin composition and converted into a volume. The density of the resin composition is measured according to JIS K7232 (1986). The calculated volume of the reinforcing fiber was divided by the sum of the volume of the reinforcing fiber and the volume of the resin composition, and multiplied by 100 to obtain Vf (fiber volume content).

<Measurement of the number of fluffs>
The bobbin of the tow prepreg obtained in each Example and Comparative Example was measured for 30 minutes or more in a temperature controlled room controlled at a temperature of 23 ± 5 ° C. and a relative humidity of 60 ± 20%, and then measured by the following method. . A bobbin around which the tow prepreg is wound is installed on the creel of the rubbing fluff device in the temperature control chamber. The tow prepreg is pulled out from the bobbin and passed through a fuzzing fluff device to produce a yarn path. The tow prepreg drawn out from the bobbin is bent at an arbitrary angle through a stainless steel free-rotating free guide bar whose surface is first hard chromium-plated and mirror-finished and has a diameter of 20 mm. Next, the surface is hard chrome plated and passed through a stainless steel fixed guide bar 1 having a diameter of 20 mm, which is not a mirror finish. At this time, the tow prepreg is set to be bent at an angle of 100 degrees from the traveling direction. The tow prepreg that has passed through the fixed guide bar 1 is bent at an arbitrary angle by passing through a fixed guide bar 2 made of the same material as that of the fixed guide bar 1, passes through a fluff counter, and is wound around a bobbin again. The fluff counter is for detecting the number of fluff by a phototransistor while irradiating a tow prepreg running with lamp light and condensing the irradiated light with a lens. As detection accuracy, fluff having a length of 2 mm or more and a carbon fiber single fiber diameter of 3 microns or more can be detected. The running speed of the tow prepreg is adjusted to 7.5 m / min, the unwinding tension when the tow prepreg is unwound from the bobbin is adjusted to 0.3 to 0.5 kgf / line, and the running is started. After confirming that the fluff is stable, the fluff counter is operated, and the evaluation of the rubbing fluff in the running state is repeated three times for 1 minute for each sample. The number of rubbing fluffs X [number / m] was calculated from the following formula (1), where the number of rubbing fluffs counted in 1 minute was X1, X2, and X3.
Formula (1): X = (X1 + X2 + X3) /22.5
<Example 1>
[Component Composition] A composition having the following composition was prepared.
Component [A]: TETRAD-X, 7 parts “Component” N, N ′-[1,3-phenylenebis (methylene)] bis [bis (oxiran-2-ylmethyl) amine]
“Viscosity at 25 ° C.” 2 Pa · s
"Manufacturer" Mitsui Gas Chemical Co., Ltd.
Component [B]: “jER (registered trademark)” 806, 67 parts “Component” Liquid bisphenol F type epoxy resin “Viscosity at 25 ° C.” 2 Pa · s
"Manufacturer" Japan Epoxy Resin Co., Ltd.
Component [C]: YDF-2001, 5 parts “Component” Solid bisphenol F type epoxy resin “Epoxy equivalent” 450 to 500 g / eq
"Glass transition temperature" 55 ° C
"Manufacturer" Toto Kasei Co., Ltd.
Component [D]: “jER Cure (registered trademark)” DICY7, 5 parts “Component” Dicyandiamide “Manufacturer” Japan Epoxy Resin Co., Ltd.
Component [E]: DCMU99, 4 parts “Component” 3-phenyl-1,1-dimethylurea, 3- (3,4-dichlorophenyl) -1,1-dimethylurea “Manufacturer” Hodogaya Chemical Co., Ltd.
Component [F]: “Kane Ace (registered trademark)” MX-125, 28 parts (including 7 parts of core-shell polymer)
“Components” bisphenol A type epoxy resin (75% by mass, corresponding to component [B]), core-shell polymer (core: copolymer of styrene and butadiene, volume average particle size: 100 nm)
“Manufacturer” Kaneka Corporation.

[Resin preparation]
28 g of TETRAD-X, 228 g of “jER (registered trademark)” 806, 20 g of YDF-2001, and 112 g of “Kane Ace (registered trademark)” MX-125 were charged into a table-type kneader and heated to a temperature of 80 ° C. The mixture was stirred and kneaded for 1 hour. After confirming that YDF-2001 has no shape and is uniformly dissolved, it is cooled to a temperature of 30 ° C., and separately, “jER Cure (registered trademark)” DICY7 and “jER (registered trademark)” are used with three rolls. “60 g of a master batch kneaded so that the weight ratio of 806 is 1: 2, was stirred and kneaded for 30 minutes. Finally, 16 g of DCMU99 was added at a temperature of 30 ° C., and the mixture was stirred and kneaded for 30 minutes, and then taken out from the desktop kneader to obtain an epoxy resin composition for tow prepreg.

[Characteristics of resin composition]
As a result of measuring the viscosity at a temperature of 25 ° C. of the obtained epoxy resin composition for tow prepreg by the above-mentioned method, it was 20 Pa · s, which was suitable for tow prepreg.

Moreover, as a result of producing a resin cured product by the above-described method and measuring the fracture toughness KIc and the glass transition temperature, KIc was 1.6 MPa / m ^0.5 and the glass transition temperature was as high as 123 ° C.

[Production of tow prepreg]
“Torayca (registered trademark)” T700SC-12K (manufactured by Toray Industries, Inc., tensile strength 4900 MPa, tensile elastic modulus 230 GPa, number of filaments 12,000, fineness 800 tex, density 1.8 g / cm ³ ) was used as the reinforcing fiber bundle. A tow prepreg was prepared by the above method.

[Characteristics of tow prepreg]
When Vf of the obtained tow prepreg was measured by the above method, it was 73%.

  Further, when the number of fluffs was measured by the above method, it was a small value of 10 pieces / m, and it was excellent in unwinding from the bobbin and process passability.

<Example 2>
[Component Composition] A composition having the following composition was prepared.
Component [A]: TETRAD-X, 7 parts “Component” N, N ′-[1,3-phenylenebis (methylene)] bis [bis (oxiran-2-ylmethyl) amine]
“Viscosity at 25 ° C.” 2 Pa · s
"Manufacturer" Mitsui Gas Chemical Co., Ltd.
Component [B]: “jER (registered trademark)” 825, 71 parts “Components” Liquid bisphenol A type epoxy resin “Viscosity at 25 ° C.” 5.6 Pa · s
"Manufacturer" Japan Epoxy Resin Co., Ltd.
Component [C]: YDF-2001, 10 parts “Component” Solid bisphenol F type epoxy resin “Epoxy equivalent” 450 to 500 g / eq
"Glass transition temperature" 55 ° C
"Manufacturer" Toto Kasei Co., Ltd.
Component [D]: “jER Cure (registered trademark)” DICY7, 4.7 parts “Component” Dicyandiamide “Manufacturer” Japan Epoxy Resin Co., Ltd.
Component [E]: “Curazole (registered trademark)” 1B2MZ, 0.5 part “Component” 2-Methyl-1- (phenylmethyl) -1H-imidazole “Manufacturer” Shikoku Kasei Kogyo Co., Ltd.
Component [F]: “Kane Ace (registered trademark)” MX-125, 16 parts (including 4 parts of core-shell polypolymer)
“Components” bisphenol A type epoxy resin (75% by mass, corresponding to component [B]), core-shell polymer (core: copolymer of styrene and butadiene, volume average particle size: 100 nm)
“Manufacturer” Kaneka Corporation.

[Resin preparation]
28 g of TETRAD-X, 246.4 g of “jER (registered trademark)” 825, 40 g of YDF-2001, and 64 g of “Kane Ace (registered trademark)” MX-125, up to a temperature of 80 ° C. The mixture was heated and stirred and kneaded for 1 hour. After confirming that YDF-2001 has no shape and is uniformly dissolved, it is cooled to a temperature of 30 ° C., and separately, “jER Cure (registered trademark)” DICY7 and “jER (registered trademark)” are used with three rolls. “56.4 g of a master batch kneaded so that the weight ratio of 825 becomes 1: 2, was stirred and kneaded for 30 minutes. Finally, 2 g of “CURAZOLE (registered trademark)” 1B2MZ was added at a temperature of 30 ° C., and after stirring and kneading for 30 minutes, the product was taken out from a table-type kneader to obtain an epoxy resin composition for tow prepreg.

[Characteristics of resin composition]
The viscosity at 25 ° C. of the obtained epoxy resin composition for tow prepreg was measured in the same manner as in Example 1. As a result, it was 27 Pa · s, which was suitable for tow prepreg.

Moreover, as a result of producing a cured resin and measuring the fracture toughness KIc and the glass transition temperature in the same manner as in Example 1, the KIc was 1.7 MPa / m ^0.5 and the glass transition temperature was as high as 120 ° C. .

[Production of tow prepreg]
“Torayca (registered trademark)” T700SC-24K (manufactured by Toray Industries, Inc., tensile strength 4900 MPa, tensile elastic modulus 230 GPa, filament number 24,000, fineness 1650 tex, density 1.8 g / cm ³ ) was used as the reinforcing fiber bundle. A tow prepreg was produced in the same manner as in Example 1.

[Characteristics of tow prepreg]
When Vf was measured for the obtained tow prepreg in the same manner as in Example 1, it was 73%.

  Further, when the number of rubbing fluffs was measured by the same method as in Example 1, it was a small value of 12 / m, and was excellent in unwinding from the bobbin and processability.

<Example 3>
[Component Composition] A composition having the following composition was prepared.
Component [A]: “ARALDITE®” MY0510, 20 parts “Components” N, N′-bis (2,3-epoxypropyl) -4- (2,3-epoxypropoxy) aniline “at 25 ° C. Viscosity "0.7 Pa · s
"Manufacturer" Huntsman Japan Co., Ltd.
Component [B]: “jER (registered trademark)” 806, 56 parts “Component” Liquid bisphenol F type epoxy resin “Viscosity at 25 ° C.” 2 Pa · s
"Manufacturer" Japan Epoxy Resin Co., Ltd.
Component [C]: YDF-2001, 10 parts “Component” Solid bisphenol F type epoxy resin “Epoxy equivalent” 450 to 500 g / eq
"Glass transition temperature" 55 ° C
"Manufacturer" Toto Kasei Co., Ltd.
Component [D]: “jER Cure (registered trademark)” DICY7, 5.4 parts “Component” Dicyandiamide “Manufacturer” Japan Epoxy Resin Co., Ltd.
Component [E]: DCMU99, 2 parts “Component” 3-phenyl-1,1-dimethylurea, 3- (3,4-dichlorophenyl) -1,1-dimethylurea “Manufacturer” Hodogaya Chemical Co., Ltd.
Component [F]: “Kane Ace (registered trademark)” MX-113, 21 parts (including 7 parts of core-shell polymer)
"Components" Bisphenol F type epoxy resin (67% by mass, corresponding to component [B]), core-shell polymer (core: copolymer of styrene and butadiene, volume average particle size: 100 nm)
“Manufacturer” Kaneka Corporation.

[Resin preparation]
80 g of “ARALDITE (registered trademark)” MY0510, 180.8 g of “jER (registered trademark)” 806, 40 g of YDF-2001, and 84 g of “Kaneace (registered trademark)” MX-113, 84 kg, The mixture was heated to a temperature of 80 ° C. and stirred and kneaded for 1 hour. After confirming that YDF-2001 has no shape and is uniformly dissolved, it is cooled to a temperature of 30 ° C., and separately, “jER Cure (registered trademark)” DICY7 and “jER (registered trademark)” are used with three rolls. “64.8 g of a master batch kneaded so that the weight ratio of 806 is 1: 2, was stirred and kneaded for 30 minutes. Finally, 8 g of DCMU99 was added at a temperature of 30 ° C., and the mixture was stirred and kneaded for 30 minutes, and then taken out from the desktop kneader to obtain an epoxy resin composition for tow prepreg.

[Characteristics of resin composition]
The viscosity at 25 ° C. of the obtained epoxy resin composition for tow prepreg was measured in the same manner as in Example 1. As a result, it was 10 Pa · s and was suitable for tow prepreg.

Moreover, as a result of producing a cured resin and measuring the fracture toughness KIc and the glass transition temperature in the same manner as in Example 1, the KIc was 1.5 MPa / m ^0.5 and the glass transition temperature was as high as 146 ° C. .

[Production of tow prepreg]
“Torayca (registered trademark)” T700SC-24K (manufactured by Toray Industries, Inc., tensile strength 4900 MPa, tensile elastic modulus 230 GPa, filament number 24,000, fineness 1650 tex, density 1.8 g / cm ³ ) was used as the reinforcing fiber bundle. A tow prepreg was produced in the same manner as in Example 1.

[Characteristics of tow prepreg]
When Vf was measured for the obtained tow prepreg in the same manner as in Example 1, it was 75%.

  Further, when the number of rubbing fluffs was measured by the same method as in Example 1, it was a small value of 5 / m and excellent in unwinding from the bobbin and process passability.

<Example 4>
[Component Composition] A composition having the following composition was prepared.
Component [A]: “ARALDITE®” MY0510, 30 parts “Components” N, N′-bis (2,3-epoxypropyl) -4- (2,3-epoxypropoxy) aniline “at 25 ° C. Viscosity "0.7 Pa · s
"Manufacturer" Huntsman Japan Co., Ltd.
Component [B]: “jER (registered trademark)” 806, 20 parts “Component” Liquid bisphenol F type epoxy resin “Viscosity at 25 ° C.” 2 Pa · s
"Manufacturer" Japan Epoxy Resin Co., Ltd.
Component [C]: YDF-2001, 20 parts “Component” Solid bisphenol F type epoxy resin “Epoxy equivalent” 450 to 500 g / eq
"Glass transition temperature" 55 ° C
"Manufacturer" Toto Kasei Co., Ltd.
Component [D]: “jER Cure (registered trademark)” DICY7, 5.3 parts “Component” Dicyandiamide “Manufacturer” Japan Epoxy Resins Co., Ltd.
Component [E]: DCMU99, 2 parts “Component” 3-phenyl-1,1-dimethylurea, 3- (3,4-dichlorophenyl) -1,1-dimethylurea “Manufacturer” Hodogaya Chemical Co., Ltd.
Component [F]: “Kane Ace (registered trademark)” MX-113, 45 parts (including 15 parts of core-shell polypolymer)
"Components" Bisphenol F type epoxy resin (67% by mass, corresponding to component [B]), core-shell polymer (core: copolymer of styrene and butadiene, volume average particle size: 100 nm)
“Manufacturer” Kaneka Corporation.

[Resin preparation]
120 g of “ALALDITE (registered trademark)” MY0510, 80 g of YDF-2001 and 180 g of “Kaneace (registered trademark)” MX-113, heated to a temperature of 80 ° C. and stirred for 1 hour Kneading was performed. After confirming that YDF-2001 has no shape and is uniformly dissolved, it is cooled to a temperature of 30 ° C., and separately, 26.5 g of “jER Cure (registered trademark)” DICY7 is added to “jER” with 3 rolls. 100.8 g of a master batch obtained by kneading 99.5 g of (registered trademark) “806” was added, and the mixture was stirred and kneaded for 30 minutes. Finally, 8 g of DCMU99 was added at a temperature of 30 ° C., and the mixture was stirred and kneaded for 30 minutes, and then taken out from the desktop kneader to obtain an epoxy resin composition for tow prepreg.

[Characteristics of resin composition]
The viscosity at 25 ° C. of the obtained epoxy resin composition for tow prepreg was measured in the same manner as in Example 1. As a result, it was 15 Pa · s, which was suitable for tow prepreg.

Moreover, as a result of producing a cured resin and measuring the fracture toughness KIc and the glass transition temperature in the same manner as in Example 1, the KIc was 1.4 MPa / m ^0.5 and the glass transition temperature was as high as 152 ° C. .

[Production of tow prepreg]
“Torayca (registered trademark)” T800SC-24K (manufactured by Toray Industries, Inc., tensile strength 5880 MPa, tensile elastic modulus 294 GPa, number of filaments 24,000, fineness 1030 tex, density 1.8 g / cm ³ ) was used as the reinforcing fiber bundle. A tow prepreg was produced in the same manner as in Example 1.

[Characteristics of tow prepreg]
When Vf was measured for the obtained tow prepreg in the same manner as in Example 1, it was 75%.

  Further, when the number of rubbing fluffs was measured by the same method as in Example 1, it was a small value of 6 / m, and was excellent in unwinding from the bobbin and process passability.

<Example 5>
[Component Composition] A composition having the following composition was prepared.
Component [A]: TETRAD-X, 10 parts “Component” N, N ′-[1,3-phenylenebis (methylene)] bis [bis (oxiran-2-ylmethyl) amine]
“Viscosity at 25 ° C.” 2 Pa · s
"Manufacturer" Mitsui Gas Chemical Co., Ltd.
Component [B]: “jER (registered trademark)” 806, 40 parts “Component” Liquid bisphenol F type epoxy resin “Viscosity at 25 ° C.” 2 Pa · s
"Manufacturer" Japan Epoxy Resin Co., Ltd.
Component [C]: YDF-2001, 20 parts “Component” Solid bisphenol F type epoxy resin “Epoxy equivalent” 450 to 500 g / eq
"Glass transition temperature" 55 ° C
"Manufacturer" Toto Kasei Co., Ltd.
Component [D]: “jER Cure (registered trademark)” DICY7, 4.7 parts “Component” Dicyandiamide “Manufacturer” Japan Epoxy Resin Co., Ltd.
Component [E]: DCMU99, 2 parts “Component” 3-phenyl-1,1-dimethylurea, 3- (3,4-dichlorophenyl) -1,1-dimethylurea “Manufacturer” Hodogaya Chemical Co., Ltd.
Component [F]: “Kane Ace (registered trademark)” MX-113, 45 parts (including 15 parts of core-shell polypolymer)
"Components" Bisphenol F type epoxy resin (67% by mass, corresponding to component [B]), core-shell polymer (core: copolymer of styrene and butadiene, volume average particle size: 100 nm)
“Manufacturer” Kaneka Corporation.

[Resin preparation]
40 g of TETRAD-X, 122 g of “jER (registered trademark)” 806, 80 g of YDF-2001 and 180 g of “Kane Ace (registered trademark)” MX-113, were put into a table type kneader and heated to a temperature of 80 ° C. The mixture was stirred and kneaded for 1 hour. After confirming that YDF-2001 has no shape and is uniformly dissolved, it is cooled to a temperature of 30 ° C., and separately, “jER Cure (registered trademark)” DICY7 and “jER (registered trademark)” are used with three rolls. “56.4 g of a master batch kneaded so that the weight ratio of 806 is 1: 2, was stirred and kneaded for 30 minutes. Finally, 8 g of DCMU99 was added at a temperature of 30 ° C., and the mixture was stirred and kneaded for 30 minutes, and then taken out from the desktop kneader to obtain an epoxy resin composition for tow prepreg.

[Characteristics of resin composition]
The viscosity at 25 ° C. of the obtained epoxy resin composition for tow prepreg was measured in the same manner as in Example 1. As a result, it was 30 Pa · s, which was suitable for tow prepreg.

Moreover, as a result of producing a cured resin and measuring the fracture toughness KIc and the glass transition temperature in the same manner as in Example 1, the KIc was 1.9 MPa / m ^0.5 and the glass transition temperature was as high as 126 ° C. .

[Production of tow prepreg]
“Torayca (registered trademark)” T700SC-24K (manufactured by Toray Industries, Inc., tensile strength 4900 MPa, tensile elastic modulus 230 GPa, filament number 24,000, fineness 1650 tex, density 1.8 g / cm ³ ) was used as the reinforcing fiber bundle. A tow prepreg was produced in the same manner as in Example 1.

[Characteristics of tow prepreg]
When Vf was measured for the obtained tow prepreg in the same manner as in Example 1, it was 71%.

  Further, when the number of rubbing fluffs was measured by the same method as in Example 1, it was a small value of 13 / m, and was excellent in unwinding from the bobbin and process passability.

<Comparative Example 1>
[Component Composition] A composition having the following composition was prepared.
Component [B]: “jER (registered trademark)” 806, 15 parts “Component” Liquid bisphenol F type epoxy resin “Viscosity at 25 ° C.” 2 Pa · s
"Manufacturer" Japan Epoxy Resin Co., Ltd.,
“JER (registered trademark)” 825, 58 parts “Components” Liquid bisphenol A type epoxy resin “Viscosity at 25 ° C.” 5.6 Pa · s
"Manufacturer" Japan Epoxy Resin Co., Ltd.
Component [C]: YDF-2001, 15 parts “Component” Solid bisphenol F type epoxy resin “Epoxy equivalent” 450 to 500 g / eq
"Glass transition temperature" 55 ° C
"Manufacturer" Toto Kasei Co., Ltd.
Component [D]: “jER Cure (registered trademark)” DICY7, 4.4 parts “Component” Dicyandiamide “Manufacturer” Japan Epoxy Resin Co., Ltd.
Component [E]: DCMU99, 4 parts “Component” 3-phenyl-1,1-dimethylurea, 3- (3,4-dichlorophenyl) -1,1-dimethylurea “Manufacturer” Hodogaya Chemical Co., Ltd.
Component [F]: “Kane Ace (registered trademark)” MX-125, 16 parts (including 4 parts of core-shell polypolymer)
“Components” bisphenol A type epoxy resin (75% by mass, corresponding to component [B]), core-shell polymer (core: copolymer of styrene and butadiene, volume average particle size: 100 nm)
“Manufacturer” Kaneka Corporation.

[Resin preparation]
"JER (registered trademark)" 806 60g, "jER (registered trademark)" 825 196.8, YDF-2001 60g and "Kaneace (registered trademark)" MX-125 64g, The mixture was heated to a temperature of 80 ° C. and stirred and kneaded for 1 hour. After confirming that YDF-2001 has no shape and is uniformly dissolved, it is cooled to a temperature of 30 ° C., and separately, “jER Cure (registered trademark)” DICY7 and “jER (registered trademark)” are used with three rolls. “52.8 g of a master batch kneaded so that the weight ratio of 825 becomes 1: 2, was stirred and kneaded for 30 minutes. Finally, 16 g of DCMU99 was added at a temperature of 30 ° C., and the mixture was stirred and kneaded for 30 minutes, and then taken out from the desktop kneader to obtain an epoxy resin composition for tow prepreg.

[Characteristics of resin composition]
As a result of measuring the viscosity at a temperature of 25 ° C. of the obtained epoxy resin composition for tow prepreg by the method described above, it was 32 Pa · s, which was suitable for tow prepreg.

Moreover, as a result of producing a resin cured product by the above-described method and measuring the fracture toughness KIc and the glass transition temperature, KIc was a high value of 1.6 MPa / m ^0.5 , but the glass transition temperature was 101 ° C. It was a low value.

[Production of tow prepreg]
“Torayca (registered trademark)” T700SC-12K (manufactured by Toray Industries, Inc., tensile strength 4900 MPa, tensile elastic modulus 230 GPa, number of filaments 12,000, fineness 800 tex, density 1.8 g / cm ³ ) was used as the reinforcing fiber bundle. A tow prepreg was prepared by the above method.

[Characteristics of tow prepreg]
When Vf of the obtained tow prepreg was measured by the above method, it was 71%.

  Further, when the number of fluffs was measured by the above method, it was a small value of 15 / m and excellent in unwinding from the bobbin and process passability.

<Comparative example 2>
[Component Composition] A composition having the following composition was prepared.
Component [A]: “ARALDITE®” MY0510, 20 parts “Components” N, N′-bis (2,3-epoxypropyl) -4- (2,3-epoxypropoxy) aniline “at 25 ° C. Viscosity "0.7 Pa · s
"Manufacturer" Huntsman Japan Co., Ltd.
Component [B]: “jER (registered trademark)” 806, 70 parts “Component” Liquid bisphenol F type epoxy resin “Viscosity at 25 ° C.” 2 Pa · s
"Manufacturer" Japan Epoxy Resin Co., Ltd.
Component [C]: YDF-2001, 10 parts “Component” Solid bisphenol F type epoxy resin “Epoxy equivalent” 450 to 500 g / eq
"Glass transition temperature" 55 ° C
"Manufacturer" Toto Kasei Co., Ltd.
Component [D]: “jER Cure (registered trademark)” DICY7, 5.4 parts “Component” Dicyandiamide “Manufacturer” Japan Epoxy Resin Co., Ltd.
Component [E]: DCMU99, 2 parts “Component” 3-phenyl-1,1-dimethylurea, 3- (3,4-dichlorophenyl) -1,1-dimethylurea “Manufacturer” Hodogaya Chemical Co., Ltd. .

[Resin preparation]
80 g of “ALALDITE (registered trademark)” MY0510, 236.8 g of “jER (registered trademark)” 806, 40 g of YDF-2001, charged in a table type kneader, heated to a temperature of 80 ° C., and stirred for 1 hour. Kneading was performed. After confirming that YDF-2001 has no shape and is uniformly dissolved, it is cooled to a temperature of 30 ° C., and separately, “jER Cure (registered trademark)” DICY7 and “jER (registered trademark)” are used with three rolls. “64.8 g of a master batch kneaded so that the weight ratio of 806 is 1: 2, was stirred and kneaded for 30 minutes. Finally, 8 g of DCMU99 was added at a temperature of 30 ° C., and the mixture was stirred and kneaded for 30 minutes, and then taken out from the desktop kneader to obtain an epoxy resin composition for tow prepreg.

[Characteristics of resin composition]
The viscosity at 25 ° C. of the obtained epoxy resin composition for tow prepreg was measured in the same manner as in Comparative Example 1 and was 7 Pa · s, which was suitable for tow prepreg.

Further, a cured resin was prepared in the same manner as in Comparative Example 1 and the fracture toughness KIc and the glass transition temperature were measured. As a result, the glass transition temperature was as high as 145 ° C., but the KIc was 0.6 MPa / m ^0. It was a low value of ⁵ .

[Production of tow prepreg]
“Torayca (registered trademark)” T700SC-24K (manufactured by Toray Industries, Inc., tensile strength 4900 MPa, tensile elastic modulus 230 GPa, filament number 24,000, fineness 1650 tex, density 1.8 g / cm ³ ) was used as the reinforcing fiber bundle. A tow prepreg was produced in the same manner as in Comparative Example 1.

[Characteristics of tow prepreg]
When Vf of the obtained tow prepreg was measured by the same method as in Comparative Example 1, it was 75%.

  Further, when the number of rubbing fluffs was measured by the same method as in Comparative Example 1, it was a small value of 5 / m and excellent in unwinding from the bobbin and process passability.

<Comparative Example 3>
[Component Composition] A composition having the following composition was prepared.
Component [A]: TETRAD-X, 30 parts “Component” N, N ′-[1,3-phenylenebis (methylene)] bis [bis (oxiran-2-ylmethyl) amine]
“Viscosity at 25 ° C.” 2 Pa · s
"Manufacturer" Mitsui Gas Chemical Co., Ltd.
Component [B]: “jER (registered trademark)” 825, 31 parts “Components” Liquid bisphenol A type epoxy resin “Viscosity at 25 ° C.” 5.6 Pa · s
"Manufacturer" Japan Epoxy Resin Co., Ltd.
Component [C]: YDF-2001, 25 parts “Component” Solid bisphenol F type epoxy resin “Epoxy equivalent” 450 to 500 g / eq
"Glass transition temperature" 55 ° C
"Manufacturer" Toto Kasei Co., Ltd.
Component [D]: “jER Cure (registered trademark)” DICY7, 5.1 parts “Component” Dicyandiamide “Manufacturer” Japan Epoxy Resins Co., Ltd.
Component [E]: DCMU99, 2 parts “Component” 3-phenyl-1,1-dimethylurea, 3- (3,4-dichlorophenyl) -1,1-dimethylurea “Manufacturer” Hodogaya Chemical Co., Ltd.
Component [F]: “Kane Ace (registered trademark)” MX-113, 21 parts (including 7 parts of core-shell polymer)
"Components" Bisphenol F type epoxy resin (67% by mass, corresponding to component [B]), core-shell polymer (core: copolymer of styrene and butadiene, volume average particle size: 100 nm)
“Manufacturer” Kaneka Corporation.

[Resin preparation]
120 g of TETRAD-X, 83.2 g of “jER (registered trademark)” 825, 100 g of YDF-2001, and 84 g of “Kane Ace (registered trademark)” MX-113, up to a temperature of 80 ° C. The mixture was heated and stirred and kneaded for 1 hour. After confirming that YDF-2001 has no shape and is uniformly dissolved, it is cooled to a temperature of 30 ° C., and separately, “jER Cure (registered trademark)” DICY7 and “jER (registered trademark)” are used with three rolls. “61.2 g of a master batch kneaded so that 825 was in a weight ratio of 1: 2 was charged and stirred and kneaded for 30 minutes. Finally, 8 g of DCMU99 was added at a temperature of 30 ° C., and the mixture was stirred and kneaded for 30 minutes, and then taken out from the desktop kneader to obtain an epoxy resin composition for tow prepreg.

[Characteristics of resin composition]
The viscosity of the resulting epoxy resin composition for tow prepreg at 25 ° C. was measured in the same manner as in Comparative Example 1. As a result, it was as high as 130 Pa · s, and was unsuitable for tow prepreg.

Moreover, as a result of producing a cured resin and measuring the fracture toughness KIc and the glass transition temperature in the same manner as in Comparative Example 1, the KIc was as high as 1.4 MPa / m ^0.5 and the glass transition temperature was 110 ° C. .

[Production of tow prepreg]
“Torayca (registered trademark)” T800SC-24K (manufactured by Toray Industries, Inc., tensile strength 5880 MPa, tensile elastic modulus 294 GPa, number of filaments 24,000, fineness 1030 tex, density 1.8 g / cm ³ ) was used as the reinforcing fiber bundle. A tow prepreg was produced in the same manner as in Comparative Example 1.

[Characteristics of tow prepreg]
When Vf was measured for the obtained tow prepreg in the same manner as in Comparative Example 1, it was 70%.

  Further, when the number of rubbing fluffs was measured by the same method as in Comparative Example 1, it was very high, 20 pieces / m or more, and the unwinding property from the bobbin and the process passability were poor.

<Comparative example 4>
[Component Composition] A composition having the following composition was prepared.
Component [B]: “jER (registered trademark)” 825, 50 parts “Component” Liquid bisphenol A type epoxy resin “Viscosity at 25 ° C.” 5.6 Pa · s
"Manufacturer" Japan Epoxy Resin Co., Ltd.
Component [C]: YDF-2001, 50 parts “Component” Solid bisphenol F type epoxy resin “Epoxy equivalent” 450 to 500 g / eq
"Glass transition temperature" 55 ° C
"Manufacturer" Toto Kasei Co., Ltd.
Component [D]: “jER Cure (registered trademark)” DICY7, 3.3 parts “Component” Dicyandiamide “Manufacturer” Japan Epoxy Resin Co., Ltd.
Component [E]: “Curazole (registered trademark)” 1B2MZ, 1 part “Component” 2-Methyl-1- (phenylmethyl) -1H-imidazole “Manufacturer” Shikoku Kasei Kogyo Co., Ltd.

[Resin preparation]
After putting 173.6 g of “jER (registered trademark)” 825 and 200 g of YDF-2001 into a table type kneader, the mixture was heated to a temperature of 80 ° C. and stirred and kneaded for 1 hour. After confirming that YDF-2001 has no shape and is uniformly dissolved, it is cooled to a temperature of 30 ° C., and separately, “jER Cure (registered trademark)” DICY7 and “jER (registered trademark)” are used with three rolls. “39.6 g of a master batch kneaded so that the weight ratio of 825 is 1: 2, was stirred and kneaded for 30 minutes. Finally, 4 g of “Curazole (registered trademark)” 1B2MZ was added at a temperature of 30 ° C., and the mixture was stirred and kneaded for 30 minutes, and then taken out from a table-type kneader to obtain an epoxy resin composition for tow prepreg.

[Characteristics of resin composition]
The viscosity of the obtained epoxy resin composition for tow prepreg at a temperature of 25 ° C. was measured in the same manner as in Comparative Example 1. As a result, it was as high as 235 Pa · s, and was unsuitable for tow prepreg.

Moreover, as a result of producing a cured resin and measuring the fracture toughness KIc and the glass transition temperature in the same manner as in Comparative Example 1, KIc was 0.8 MPa / m ^0.5 , and the glass transition temperature was a low value along with 87 ° C. .

[Production of tow prepreg]
“Torayca (registered trademark)” T700SC-24K (manufactured by Toray Industries, Inc., tensile strength 4900 MPa, tensile elastic modulus 230 GPa, filament number 24,000, fineness 1650 tex, density 1.8 g / cm ³ ) was used as the reinforcing fiber bundle. A tow prepreg was produced in the same manner as in Comparative Example 1.

[Characteristics of tow prepreg]
When Vf was measured for the obtained tow prepreg in the same manner as in Comparative Example 1, it was 70%.

  Further, when the number of rubbing fluffs was measured by the same method as in Comparative Example 1, it was very high, 20 pieces / m or more, and the unwinding property from the bobbin and the process passability were poor.

Claims (12)

An epoxy resin composition comprising at least the following constituent elements [A] to [F] and having a viscosity at 25 ° C. of 60 Pa · s or less, wherein the epoxy resin composition is cured at a temperature of 135 ° C. for 2 hours. An epoxy resin composition for a tow prepreg characterized by having a fracture toughness (KIc) of the product of 1 MPa · m ^0.5 or more.
[A] Epoxy resin having 1 or more aromatic rings or cyclohexane rings and 3 to 4 epoxy groups in one molecule, and a viscosity at 25 ° C. of 5 Pa · s or less [B] Two in one molecule Bisphenol F type epoxy resin [D] having an epoxy group [C] having a viscosity of 70 Pa · s or less at 25 ° C. and having an epoxy equivalent in the range of 350 to 700 g / eq and solid at 25 ° C. Dicyandiamide [E] Curing accelerator [F] Core-shell polymer whose core component is a copolymer containing at least styrene and butadiene 2. The tow prepreg according to claim 1, wherein the shell component of the core-shell polymer as the constituent element [F] contains at least methyl methacrylate and styrene and further has a functional group that reacts with an epoxy resin. Epoxy resin composition. The epoxy resin composition for tow prepregs according to claim 1 or 2, wherein the core-shell polymer as the constituent element [F] has a volume average particle diameter of 1 to 500 nm. The epoxy resin composition for tow prepreg according to any one of claims 1 to 3, wherein the compounding amount of component [A] is 5 to 30 parts by mass in 100 parts by mass of all epoxy resin components. The compounding quantity of component [C] is the epoxy resin composition for tow prepregs in any one of Claims 1-4 which is 5-20 mass parts in 100 mass parts of all the epoxy resin components. The epoxy for tow prepreg according to any one of claims 1 to 5, wherein the component [A] is N, N-bis (2,3-epoxypropyl) -4- (2,3-epoxypropoxy) aniline. Resin composition. The epoxy resin composition for tow prepreg according to any one of claims 1 to 6, wherein the constituent element [E] is 3- (3,4-dichlorophenyl) -1,1-dimethylurea. A tow prepreg obtained by impregnating a reinforcing fiber bundle comprising 1,000 to 70,000 filaments with the epoxy resin composition for tow prepreg according to any one of claims 1 to 7. The tow prepreg according to claim 8, wherein the reinforcing fiber is a carbon fiber. The tow prepreg according to claim 9, wherein the carbon fiber has a tensile modulus of 180 to 400 GPa. The tow prepreg according to any one of claims 8 to 10, wherein the reinforcing fiber has a volume content of 50 to 75%. 12. The tow prepreg according to claim 8, wherein the number of abrasion fluffs measured by the abrasion fluff evaluation method is 20 or less per 1 m.