JP2020023691A - Fiber-reinforced resin - Google Patents

Abstract

To provide a fiber-reinforced resin excellent in dynamic characteristics such as impact resistance.SOLUTION: A fiber-reinforced resin is molded by impregnating a reinforcing fiber base material 11 with an epoxy resin composition and heating and curing the base material, [1] the reinforcing fiber base material is formed of a reinforcing fiber base material in which a porous resin material 13 formed of copolymerized polyamide containing at least two polyamide components on at least one surface of a reinforcing fiber assembly 12 is arranged, [2] the epoxy resin composition is formed of an epoxy resin and a curing agent, 70 pts.mass or more and 100 pts.mass or less of tetraglycidyl diaminodiphenyl methane [A] is contained with respect to 100 pts.mass of the total epoxy resin component, 80 pts.mass or more and 100 pts.mass or less of 4,4'-methylene bis(2-isopropyl-6-methyl aniline)[B] is contained with respect to 100 pts.mass of the total curing agent component, and resin viscosities at 30°C and 80°C satisfy a specific relationship.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fiber reinforced resin obtained by impregnating a reinforcing fiber base with an epoxy resin composition.

  BACKGROUND ART A fiber reinforced resin (FRP) obtained by impregnating a reinforcing fiber with a matrix resin has been mainly used for aviation, space, and sports because it satisfies required characteristics such as excellent mechanical properties and weight reduction. As a typical production method thereof, an autoclave molding method is known. In such a molding method, a prepreg obtained by impregnating a reinforcing fiber bundle group with a matrix resin in advance is laminated on a molding die, and heated and pressed by an autoclave to form an FRP. The use of a prepreg has the advantage that an extremely reliable FRP can be obtained, but has the problem of high manufacturing costs.

  On the other hand, as a molding method excellent in productivity of FRP, for example, injection molding such as a resin transfer molding molding method (RTM) is exemplified. In the RTM molding method, a reinforcing fiber base composed of a group of dry reinforcing fiber bundles not pre-impregnated with a matrix resin is laminated on a molding die, and a liquid, low-viscosity matrix resin is injected into the mold. This is a molding method in which a matrix resin is impregnated and solidified to form an FRP.

  Although the injection molding method is excellent in the productivity of FRP, the matrix resin needs to have a low viscosity, so it exhibits sufficient mechanical properties compared to FRP molded from a high viscosity matrix resin used for prepreg. In some cases, it was not possible.

  As a solution to the above, for example, as disclosed in Patent Document 1 or Patent Document 2, an intermediate layer in which a unidirectional layer of carbon fiber having a prescribed basis weight and a thermoplastic fiber web (nonwoven fabric) having a prescribed thickness are combined. Materials have been proposed. However, it is disclosed that when these thermoplastic fiber webs are used, certain mechanical properties can be exhibited.However, depending on the curing properties of the epoxy resin used for molding, sufficient impact resistance cannot be exhibited. was there.

JP-T-2012-506499A JP 2008-517812 A

  The present invention has been made to solve the problems of the related art, and an object of the present invention is to provide a fiber-reinforced resin having excellent mechanical properties such as impact resistance (particularly, compressive strength after impact: CAI).

The present invention employs the following means in order to solve such a problem. That is,
(1) A fiber-reinforced resin formed by impregnating a reinforcing fiber base material with an epoxy resin composition and curing by heating.
[1] The reinforcing fiber base material is (a): a reinforcing fiber yarn, (b): a group of reinforcing fiber yarns in which reinforcing fiber yarns are aligned in parallel, (c): (a) or (b) The reinforcing fiber fabric selected from the group consisting of polyamide 6, polyamide 6-6, polyamide 6-10, polyamide 12, and polyamide 6-I. Consisting of a reinforcing fiber base material in which a porous resin material made of a copolyamide containing one polyamide component is arranged,
[2] The epoxy resin composition comprises an epoxy resin and a curing agent, and contains not less than 70 parts by mass and not more than 100 parts by mass of tetraglycidyldiaminodiphenylmethane [A] based on 100 parts by mass of all epoxy resin components. , 4,4'-methylenebis (2-isopropyl-6-methylaniline) [B] is contained in an amount of 80 parts by mass or more and 100 parts by mass or less based on 100 parts by mass of all the curing agent components, and at 30 ° C and 80 ° C. A resin viscosity of η30, η80 (unit: mPa · s), wherein the fiber reinforced resin comprises an epoxy resin composition satisfying 200 ≦ η30 / η80 ≦ 500 and 50 ≦ η80 ≦ 200. .
(2) The fiber-reinforced resin according to (1), wherein the porous resin material has a content of 1 to 20% by weight based on the reinforcing fiber base material.
(3) The fiber reinforced resin according to (1) or (2), wherein the porous resin material has a nonwoven fabric shape and a fiber diameter of 1 to 100 μm.
(4) The fiber reinforced resin according to any one of (1) to (3), wherein the composition ratio of polyamide 12 in the porous resin material is in a range of 5 mol% or more and less than 99 mol%.
(5) The fiber-reinforced resin according to any one of (1) to (4), wherein the group of reinforcing fiber yarns is a sheet having a plurality of reinforcing fiber yarns arranged in parallel.
(6) The fiber according to any one of (1) to (4), wherein the reinforcing fiber yarn group is a sheet-like shape in which reinforcing fiber yarns are arranged in parallel by an automated fiber placement device. Reinforced resin.
(7) The reinforcing fiber assembly is a group of reinforcing fiber yarns in which reinforcing fiber yarns are arranged in parallel in one direction, and a reinforcing fiber yarn extending in a direction intersecting the reinforcing fiber yarns. The fiber reinforced resin according to any one of (1) to (4), which is a unidirectional woven fabric comprising an auxiliary fiber yarn group having a fineness of 1/5 or less.
(8) The reinforcing fiber aggregate is a bidirectional woven fabric composed of the reinforcing fiber yarn groups arranged in one direction and the reinforcing fiber yarn groups arranged in one direction in different directions. The fiber-reinforced resin according to any one of (1) to (4).
(9) In the reinforcing fiber cloth, at least two layers of the reinforcing fiber yarn group arranged in one direction and the reinforcing fiber yarn group arranged in one direction in different directions are cross-laminated, and the fineness is reduced. The fiber reinforced resin according to any one of (1) to (4), which is a stitched fabric stitched and integrated by an auxiliary fiber yarn group that is 1/5 or less of the reinforcing fiber yarn.
(10) The volume content of the reinforcing fiber is in the range of 53 to 65%, and the room temperature compressive strength after impact application described in SACMA-SRM-2R-94 is 240 MPa or more, (1) to (9). The fiber-reinforced resin according to any one of the above.
It is.

  According to the present invention, it is possible to obtain an FRP having excellent mechanical properties such as impact resistance.

FIG. 1 is a schematic cross-sectional view illustrating one embodiment of a reinforcing fiber base according to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic side view which shows one aspect of the manufacturing apparatus of the reinforcing fiber base in this invention. It is a schematic perspective view showing one mode of a reinforcing fiber thread group in the present invention. It is a schematic perspective view showing one mode of a unidirectional textile as a reinforcing fiber aggregate in the present invention. FIG. 1 is a schematic perspective view showing one embodiment of a bidirectional woven fabric as a reinforcing fiber aggregate according to the present invention. It is a schematic perspective view showing one mode of a stitch cloth as a reinforcing fiber aggregate in the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view illustrating one embodiment of a reinforcing fiber base material 11 according to the present invention. The reinforcing fiber base 11 shown in this figure is one in which the resin material 13 is disposed on one surface of the reinforcing fiber assembly 12 and then bonded and integrated.

  The reinforcing fiber base material 11 is a reinforcing fiber aggregate 12 selected from a group consisting of a reinforcing fiber yarn, a group of reinforcing fiber yarns, and a reinforcing fiber cloth or a reinforcing fiber cloth composed of a group of reinforcing fiber yarns. It is important to have the resin material 13 on at least one surface. By providing such a resin material 13 on at least one surface, it is possible to improve the morphological stability such as the width and fiber orientation of the reinforcing fiber base material 11 or to obtain a sheet-like reinforcing fiber base made of a group of reinforcing fiber yarns. It is possible to improve the handling property of the material 11 during transportation or the like.

  In addition, it is possible to impart adhesiveness between the reinforcing fiber aggregates 12 when obtaining a laminate (preform) obtained by laminating the reinforcing fiber base material 11 or the reinforcing fiber aggregates 12 described below, or it is possible to provide a suitable preform. The handleability of the preform can be improved, for example, rigidity can be imparted, and a form stability effect such as prevention of misalignment of reinforcing fibers in the preform can be imparted.

  In particular, the resin material 13 can secure a space for flowing and diffusing a matrix resin, which will be described later, between the layers of the reinforcing fiber assembly 12 (giving the matrix resin a plastic deformability between the layers of the reinforcing fiber assembly 12). When the resin material 13 acts as a stopper for cracks generated between the layers of the reinforcing fiber assembly 12 or the like, it is possible to suppress the damage between the layers of the reinforcing fiber assembly 12 when subjected to an impact, and particularly excellent mechanical properties. (Especially CAI) can be achieved. In addition, the resin material 13 serves as a spacer to secure a flow path of the matrix resin between the layers of the reinforcing fiber assembly 12 and not only facilitates impregnation of the matrix resin when subjected to injection molding, but also the The effect of increasing the impregnation rate and improving the productivity of FRP is also exhibited.

  The resin material 13 adheres to the reinforcing fiber assembly 12 and only needs to be present on at least one surface of the reinforcing fiber assembly 12, and exists inside the reinforcing fiber assembly 12 (permeates into the reinforcing fiber yarns). May be. Preferably, 50% by weight or more, more preferably 70% by weight or more, is unevenly distributed on the surface of the reinforcing fiber aggregate 12 for the above-described reason. Further, a binder component may be included for the purpose of bonding the resin material 13 and the reinforcing fiber bundle 12. For example, a thermoplastic resin having a lower softening point than the resin material 13 or a thermosetting resin can be used.

  It is important that the resin material 13 of the reinforcing fiber base material 11 in the present invention is porous. In the present invention, “porous” refers to a shape in which holes are formed in a thickness direction on a plane, and in such a form, the flow of a matrix resin or air flows in the thickness direction of the reinforcing fiber base material 11. Not only can the path be secured, but also there is a connection in the plane direction, so that the width stability is improved when the reinforcing fiber yarn is used, and when the sheet-like reinforcing fiber base material 11 composed of the group of reinforcing fiber yarns is conveyed. And the form stability of the base material when a group of reinforcing fiber yarns or a fabric is used can be improved. Examples of the porous resin material 13 include a nonwoven fabric, a mat, a net, a mesh, a fabric, a knit, a short fiber group, a perforated film, and a porous film. Among them, a nonwoven fabric, a mat, or a mesh is preferable because it can be obtained at a low cost, and a matrix resin or an air flow path is also formed in a plane direction, so that the above-mentioned effects are exhibited to a high degree. When the resin material 13 is a non-woven fabric, the form of the constituent fibers includes long fibers and short fibers, and is produced by a method such as melt blowing, spun bonding, air laid, carding, and papermaking, but is not particularly limited. Further, a binder component for binding fibers to each other may be included as an auxiliary component. The fiber diameter of the constituent fibers is preferably 1 μm or more and 100 μm or less, more preferably 5 μm or more and less than 80 μm, and even more preferably 10 μm or more and 60 μm or less. If the fiber diameter is less than 1 μm, the surface area of the resin material becomes large, and the flow of the resin may be hindered in the resin impregnation step described below, which is not preferable. On the other hand, if the fiber diameter exceeds 100 μm, the thickness between the reinforcing fiber base layers when FRP is formed becomes large, and the fiber volume content (Vf) decreases, which is not preferable.

  It is important that the resin material 13 is a copolymer polyamide containing at least two polyamide components selected from polyamide 6, polyamide 6-6, polyamide 6-10, polyamide 12, and polyamide 6-I. Such a resin material 13 can form a layer having high toughness between the FRP layers, and can enhance mechanical properties (particularly, CAI).

  The resin material 13 used in the present invention preferably accounts for 1 to 20% by weight of the reinforcing fiber base material 11. Preferably it is 2 to 18% by weight, more preferably 3 to 16% by weight. By arranging the resin material 13 within the above range, the morphological stability of the reinforcing fiber base material 11 is provided, and it is possible to obtain the reinforcing fiber base material 11 having excellent handleability. If the content is less than 1% by weight, not only is the handleability of the reinforcing fiber base material 11 reduced, but also the effect of improving the mechanical properties (particularly, CAI) is undesirably reduced. On the other hand, if it exceeds 20% by weight, the volume content of the reinforcing fibers in the FRP becomes too low, and the heat resistance, the chemical resistance and the compressive strength of the FRP are undesirably reduced.

  Further, the softening point of the resin material 13 used in the present invention is preferably 80 to 220 ° C. The temperature is more preferably in the range of 100 to 200 ° C, and still more preferably in the range of 120 to 180 ° C. Here, in the present invention, the softening point indicates a melting point when the resin material is a crystalline polymer and a glass transition temperature when the resin material is an amorphous polymer, and is determined by using a differential scanning calorimeter (DSC) according to JIS K7121 (1987). Refers to a value measured at a heating rate of 10 ° C./min. If the softening point is lower than 80 ° C., the heat resistance of the FRP decreases, which is not preferable. If the softening point exceeds 220 ° C., the adhesiveness between the matrix resin and the resin material 13 is reduced, and the mechanical properties of FRP (particularly, CAI and ILSS [interlaminar shear strength]) may be reduced. That is, it is desirable that the upper limit of the softening point of the resin material 13 is lower than the molding temperature during FRP molding.

  Here, among the polyamide components constituting the resin material 13 described above, the polyamide 6-I is an amorphous polymer. Therefore, when the polyamide 6-I does not include the polyamide 6-I or the blending ratio is low, the copolymer polyamide 6-I is used. Tends to be a crystalline polymer, and when polyamide 6-I is the main component, it tends to be an amorphous polymer.

  It is preferable that the resin material 13 contains polyamide 12 having a low water absorption from the viewpoint of suppressing a decrease in mechanical properties of the FRP under the moist heat condition. Therefore, the proportion of the polyamide 12 in the resin material 13 is 5 mol% or more, preferably 50 mol% or more, and more preferably 80 mol% or more. Examples of the resin material that can be copolymerized with the polyamide 12 include polyamide 6, polyamide 6-6, polyamide 4-6, polyamide 6-10, polyamide 6-12, polyamide 6-T, polyamide 6-I, and polyamide 6 6 / 6-T, polyamide 6-6 / 6-I, polyamide 6-6 / 6-T / 6-I and the like. Particularly preferred are polyamide 6, polyamide 6-6, polyamide 6-10, polyamide 12, and polyamide 6-I. These resin materials are further required to have required properties such as processability, heat resistance, and toughness. It is also suitable to use as a mixture accordingly.

  Further, when the compatibility of the FRP with the matrix resin is low when the resin material 13 is melted during molding, separation occurs at the interface between the resin material 13 and the matrix resin, and the effect of improving the mechanical properties can be obtained satisfactorily. There are things you can't do. Therefore, the absolute value of the solubility parameter difference between the resin material 13 and the matrix resin is preferably 5 or less, more preferably 3 or less. The solubility parameter of the resin material 13 is obtained by the following equation (1). This method is described in "Fukumoto Osamu (1988)" Polyamide Resin Handbook "Nikkan Kogyo Shimbun".

In the above equation (1),
M: molecular weight ρ: density ΔH: amide group interaction T: temperature.

  The solubility parameter of the matrix resin is determined by the value of the repeating unit of the polymer at a temperature of 25 ° C. determined by the method of Fedors. The method is described in F.S. Fedors, Polym. Eng. Sci. , 14 (2), 147 (1974).

Next, the epoxy resin composition of the present invention will be described.
The epoxy resin composition of the present invention contains not less than 70 parts by mass and not more than 100 parts by mass of tetraglycidyldiaminodiphenylmethane [A] based on 100 parts by mass of all epoxy resin components, and 4,4′-methylenebis (2 -Isopropyl-6-methylaniline) [B] is contained in an amount of 80 parts by mass or more and 100 parts by mass or less based on 100 parts by mass of all the curing agent components, and the resin viscosity at 30 ° C and 80 ° C is η30, η80 (unit). : MPa · s), the epoxy resin composition satisfies 200 ≦ η30 / η80 ≦ 500 and 50 ≦ η80 ≦ 200.

  Since the epoxy resin composition having such characteristics has good adhesiveness to the resin material 13, it can exhibit excellent impact resistance (particularly CAI).

  In addition, the resin composition containing the above-mentioned parts by mass of the components [A] and [B] and satisfying the above-mentioned viscosity range achieves improvement in handleability at the time of freezing transportation, which was difficult in the prior art, and at normal temperature. Even during the holding, the rise in viscosity is suppressed for a long time, the stability is high, the impregnation property is excellent, and sufficient high-speed curing can be performed at a high temperature of 180 ° C. In addition, during the demolding step after molding, the resin is sufficiently cured and high heat resistance is imparted, so that the demolding can be performed smoothly and the obtained FRP has improved 0 ° compressive strength when wet and hot. it can.

  The component [A] in the present invention is tetraglycidyldiaminodiphenylmethane, and is a component necessary for imparting high heat resistance and mechanical properties to the cured resin and FRP. Here, the tetraglycidyldiaminodiphenylmethane of the component [A] means N, N, N ', N'-tetraglycidyldiaminodiphenylmethane, or a derivative or isomer thereof. For example, N, N, N ', N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N, N, N', N'-tetraglycidyl-3,3'-dimethyl-4,4'-diaminodiphenylmethane , N, N, N ', N'-tetraglycidyl-3,3'-diethyl-4,4'-diaminodiphenylmethane, N, N, N', N'-tetraglycidyl-3,3'-diisopropyl-4 , 4'-Diaminodiphenylmethane, N, N, N ', N'-tetraglycidyl-3,3'-di-t-butyl-4,4'-diaminodiphenylmethane, N, N, N', N'-tetra Glycidyl-3,3'-dimethyl-5,5'-diethyl-4,4'-diaminodiphenylmethane, N, N, N ', N'-tetraglycidyl-3,3'-diisopropyl-5,5'-diethyl 4,4′-diaminodiphenylmethane, N, N, N ′, N′-tetraglycidyl-3,3′-diisopropyl-5,5′-dimethyl-4,4′-diaminodiphenylmethane, N, N, N ′, N'-tetraglycidyl-3,3'-di-t-butyl-5,5'-diethyl-4,4'-diaminodiphenylmethane, N, N, N ', N'-tetraglycidyl-3,3'- Di-tert-butyl-5,5'-dimethyl-4,4'-diaminodiphenylmethane, N, N, N ', N'-tetraglycidyl-3,3', 5,5'-tetramethyl-4,4 '-Diaminodiphenylmethane, N, N, N', N'-tetraglycidyl-3,3 ', 5,5'-tetraethyl-4,4'-diaminodiphenylmethane, N, N, N', N'-tetraglycidyl -3,3 ', 5 '-Tetraisopropyl-4,4'-diaminodiphenylmethane, N, N, N', N'-tetraglycidyl-3,3 ', 5,5'-tetra-t-butyl-4,4'-diaminodiphenylmethane, N, N, N ', N'-tetraglycidyl-3,3'-dichloro-4,4'-diaminodiphenylmethane, N, N, N', N'-tetraglycidyl-3,3'-dibromo-4, 4'-diaminodiphenylmethane and the like. Further, as the component [A], two or more of these tetraglycidyldiaminodiphenylmethanes may be used in combination.

  Commercial products of tetraglycidyldiaminodiphenylmethane include "Sumiepoxy (registered trademark)" ELM434 (manufactured by Sumitomo Chemical Co., Ltd.), YH434L (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), and "jER (registered trademark)" 604 (Mitsubishi Chemical). And Araldite (registered trademark) MY720, and "Araldite (registered trademark)" MY721 (all manufactured by Huntsman Advanced Materials).

  The component [A] in the present invention needs to be contained in an amount of 70 parts by mass or more and 100 parts by mass or less based on 100 parts by mass of all epoxy resin components. When the component [A] is contained in an amount of 70 parts by mass or more with respect to 100 parts by mass of all the epoxy resin components, the cured resin exhibits high heat resistance and the 0 ° compressive strength of the FRP when wet is improved. preferable. From such a viewpoint, the content is more preferably in the range of 80 parts by mass to 100 parts by mass.

  Bisphenol type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, resorcinol type epoxy resin, phenol aralkyl type epoxy resin, naphthol aralkyl type epoxy resin, dicyclopentadiene which are epoxy resins other than component [A] Type epoxy resin, epoxy resin having a biphenyl skeleton, isocyanate-modified epoxy resin, tetraphenylethane type epoxy resin, triphenylmethane type epoxy resin, triglycidylamine type epoxy resin, etc. If it is less than 30 parts by mass with respect to 100 parts by mass of the epoxy resin component, it may be contained.

  More specifically, as the epoxy resin other than the component [A], bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, tetrabromobisphenol A diglycidyl ether, bisphenol AD diglycidyl ether, 2,2 ′, 6, 6'-tetramethyl-4,4'-biphenol diglycidyl ether, 9,9-bis (4-hydroxyphenyl) fluorene diglycidyl ether, tris (p-hydroxyphenyl) methane triglycidyl ether, tetrakis (p- (Hydroxyphenyl) ethane tetraglycidyl ether, phenol novolak glycidyl ether, cresol novolac glycidyl ether, glycidyl ether of a condensate of phenol and dicyclopentadiene, biphenylaralkyl Glycidyl ether of fat, triglycidyl isocyanurate, 5-ethyl-1,3-diglycidyl-5-methylhydantoin, oxazolidone type epoxy resin obtained by addition of bisphenol A diglycidyl ether and tolylene isocyanate, phenol aralkyl type epoxy resin, Triglycidylaminophenol and the like. Among them, bisphenol-type epoxy resin is preferably used because it provides an excellent contribution to the balance of toughness and heat resistance of the cured resin, and in particular, liquid bisphenol-type epoxy resin gives an excellent contribution to the impregnation into the reinforcing fiber, It is preferably used as an epoxy resin other than the component [A]. In the present invention, “liquid” means that the viscosity at 25 ° C. is 1000 Pa · s or less, and “solid” has no fluidity at 25 ° C. or extremely low fluidity. Specifically, it means that the viscosity at 25 ° C. is greater than 1000 Pa · s. Here, the viscosity is measured according to JIS Z8803 (1991) “Viscosity measurement method using cone-plate rotational viscometer”, using an E-type viscometer equipped with a standard cone rotor (1 ° 34 ′ × R24) (for example, ) Measured using Tokimec TVE-30H).

  Here, the bisphenol type epoxy resin is a bisphenol compound in which two phenolic hydroxyl groups of a bisphenol compound are glycidylated, and the bisphenol type is bisphenol A type, bisphenol F type, bisphenol AD type, bisphenol S type, or these. Examples include halogen, alkyl-substituted bisphenols, hydrogenated products, and the like. Further, the bisphenol-type epoxy resin is not limited to a monomer, and a high-molecular-weight polymer having a plurality of repeating units can be suitably used. When a bisphenol-type epoxy resin is contained from the viewpoint of the balance between the toughness and heat resistance of the cured resin, the content is preferably less than 30 parts by mass based on 100 parts by mass of all the epoxy resin components.

  Commercially available bisphenol A type epoxy resins include “jER (registered trademark)” 825, “jER (registered trademark)” 826, “jER (registered trademark)” 827, “jER (registered trademark)” 828, and “jER (registered trademark)”. (Registered trademark) "834," jER (registered trademark) "1001," jER (registered trademark) "1002," jER (registered trademark) "1003," jER (registered trademark) "1004," jER (registered trademark) "1004AF. , "JER (registered trademark)" 1007, "jER (registered trademark)" 1009 (manufactured by Mitsubishi Chemical Corporation), "Epiclon (registered trademark)" 850 (manufactured by DIC Corporation), "Epototo (registered trademark)" "YD-128 (manufactured by Nippon Steel & Sumitomo Metal Corporation)," DER (registered trademark) "-331," DER (registered trademark) "-332 (manufactured by Dow Chemical Company) and the like.

  Commercially available bisphenol F type epoxy resins include “jER (registered trademark)” 806, “jER (registered trademark)” 807, “jER (registered trademark)” 1750, “jER (registered trademark)” 4004P, and “jER (registered trademark)”. (Trademark) "4007P", "jER (registered trademark)" 4009P (all manufactured by Mitsubishi Chemical Corporation), "Epiclon (registered trademark)" 830 (manufactured by DIC Corporation), "Epototo (registered trademark)" YDF-170, “Epototo (registered trademark)” YDF2001, “Epototo (registered trademark)” YDF2004 (all Nippon Steel & Sumitomo Metal Corporation) and the like. Commercial products of the alkyl-substituted tetramethylbisphenol F type epoxy resin include “Epototo (registered trademark)” YSLV-80XY (Nippon Steel & Sumitomo Metal Corporation).

  Examples of commercially available bisphenol S type epoxy resins include “Epiclon (registered trademark)” EXA-1515 (manufactured by DIC Corporation).

  [B] in the present invention is 4,4′-methylenebis (2-isopropyl-6-methylaniline), which realizes high-speed curing of the resin composition and imparts high mechanical properties to the cured resin and FRP. Necessary component. Commercial products of such 4,4'-methylenebis (2-isopropyl-6-methylaniline) include "Lonzacure (registered trademark)" M-MIPA (manufactured by Lonza Corporation).

  The component [B] in the present invention needs to be contained in an amount of 80 parts by mass or more and 100 parts by mass or less based on 100 parts by mass of all the curing agent components. When the component [B] is contained in an amount of 80 parts by mass or more based on 100 parts by mass of the total curing agent component, high-speed curability at a high temperature of 180 ° C is exhibited, and a low-temperature viscosity at -20 ° C is high. Good handling during freezing and high viscosity at room temperature at 25 ° C. Suppresses the molecular movement of epoxy and curing agent, and suppresses the curing reaction. On the other hand, the viscosity at the resin impregnation temperature of 80 ° C. is sufficiently low, the impregnating property is good, and the 0 ° compressive strength of FRP when wet heat is improved is preferable. From such a viewpoint, the content is more preferably in the range of 90 parts by mass or more and 100 parts by mass or less.

  Further, as a curing agent other than the component [B], a compound having an active group capable of reacting with an epoxy resin may be contained as long as it is less than 20 parts by mass based on 100 parts by mass of all curing agent components. As the active group capable of reacting with the epoxy resin, for example, those having an amino group or an acid anhydride group can be used. The epoxy resin composition is preferably as high in storage stability as possible, but the liquid curing agent is preferably solid at room temperature because of its high reactivity.

  The curing agent other than the component [B] is preferably an aromatic amine, and preferably has 1 to 4 phenyl groups in the molecule from the viewpoint of heat resistance and mechanical properties. Furthermore, since the resin elastic modulus is improved by imparting the flexibility of the molecular skeleton and the mechanical properties can be improved, at least one phenyl group contained in the skeleton of the epoxy resin curing agent has an amino group at the ortho or meta position. More preferably, the aromatic polyamine compound is a phenyl group having a group. Specific examples of aromatic polyamines include various derivatives such as metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, metaxylylenediamine, diphenyl-p-dianiline and their alkyl-substituted products, and isomers having different amino group positions. Body and the like. These curing agents can be used alone or in combination of two or more. Above all, diaminodiphenylmethane and diaminodiphenylsulfone are preferred from the viewpoint of giving high heat resistance to the cured resin.

  Commercially available aromatic polyamine curing agents include Seika Cure S (manufactured by Wakayama Seika Kogyo Co., Ltd.), MDA-220 (manufactured by Mitsui Chemicals, Inc.), "jER Cure (registered trademark)" W (Mitsubishi Chemical Corporation) )), And 3,3'-DAS (manufactured by Mitsui Chemicals, Inc.), "Lonzacure (registered trademark)" M-DEA (manufactured by Lonza), "Lonzacure (registered trademark)" M-DIPA (Lonza) And "Lonzacure (registered trademark)" M-CDEA (manufactured by Lonza) and "Lonzacure (registered trademark)" DETDA 80 (manufactured by Lonza).

  In the present invention, H / E, which is the ratio of the total number of epoxy groups (E) contained in the epoxy resin to the total number of active hydrogens (H) of the amine compound contained in the curing agent, is 1.1 or more and 1.4 or less. And more preferably 1.2 or more and 1.3 or less. When H / E is 1.1 or more, a favorable effect of improving the curability and an effect of improving the plastic deformation ability of the cured resin are obtained, and when it is 1.4 or less, high heat resistance is obtained. Is preferred because

  The epoxy resin composition of the present invention may contain core-shell rubber particles. Core-shell rubber particles are excellent in imparting high toughness to FRP. Here, the core-shell rubber particle is a particle in which a part or the whole of the core surface is coated by a method such as graft polymerization of a particle-shaped core portion mainly composed of a polymer such as a crosslinked rubber and a polymer different from the core portion. Means

  As the core portion of the core-shell rubber particles, a polymer polymerized from one or more selected from conjugated diene-based monomers, acrylate-based monomers, and methacrylate-based monomers, or a silicone resin can be used. Specifically, for example, butadiene, isoprene, and chloroprene can be mentioned, and a crosslinked polymer composed of one or more of these is preferable. Particularly, since the properties of the obtained polymer are good and the polymerization is easy, it is preferable to use butadiene as such a conjugated diene-based monomer, that is, it is preferable to use a polymer polymerized from a monomer containing butadiene as a core component. .

  The shell component constituting the core-shell rubber particles is preferably graft-polymerized to the above-mentioned core component, and is preferably chemically bonded to the polymer particles constituting 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. In addition, it is preferable that a component contained in the epoxy resin composition of the present invention, that is, a functional group that reacts with the epoxy resin or its curing agent component is introduced into the shell component in order to stabilize the dispersion state. When such a functional group is introduced, the affinity with the epoxy resin is improved, and finally, it is possible to react with the epoxy resin composition and to be taken into the cured product, so that good dispersion is obtained. Sex can be achieved. As a result, a sufficient toughness improving effect can be obtained even with a small amount of blending, and it becomes possible to improve toughness while maintaining Tg and elastic modulus. Examples of such a functional group include a hydroxyl group, a carboxyl group, and an epoxy group. As a method for introducing such a functional group into the shell portion, one or more components such as acrylates and methacrylates containing such a functional group are added to the core surface as a partial component of the monomer. Examples of the method include graft polymerization.

  The core-shell rubber particles preferably have a volume average particle diameter of 50 nm or more and 300 nm or less, and more preferably 50 nm or more and 150 nm or less. The volume average particle diameter can be measured using a Nanotrac particle size distribution measuring device (manufactured by Nikkiso Co., Ltd., dynamic light scattering method). Alternatively, a thin section of a cured product prepared by a microtome can be observed with a TEM (transmission electron microscope), and the volume average particle diameter can be measured from the obtained TEM image using image processing software. In this case, it is necessary to use the average value of at least 100 particles. When the volume average particle size is 50 nm or more, the specific surface area of the core-shell rubber particles is moderately small, which is advantageous in terms of energy, so that aggregation does not easily occur and the effect of improving toughness is high. On the other hand, when the volume average particle diameter is 300 nm or less, the distance between the core-shell rubber particles becomes appropriately small, and the effect of improving toughness is high.

  The method for producing the core-shell rubber particles is not particularly limited, and those produced by a known method can be used. Examples of commercially available core-shell rubber particles include, for example, “PARALOID (registered trademark)” EXL-2655 (manufactured by Rohm & Haas Co.) composed of a butadiene-alkyl methacrylate-styrene copolymer, and an acrylate-methacrylate copolymer. “PARALOID (registered trademark)” EXL-2611, which is composed of “STAPHYLOID (registered trademark)” AC-3355, TR-2122 (manufactured by Ganz Kasei Co., Ltd.), and butyl acrylate / methyl methacrylate copolymer. , EXL-3387 (manufactured by Rohm & Haas) or the like can be used. Further, a core layer of a glassy polymer having a glass transition temperature of room temperature or higher, such as staphyloid IM-601 and IM-602 (all manufactured by Ganz Kasei Co., Ltd.), is covered with an intermediate layer of a rubbery polymer having a low Tg. Further, core-shell rubber particles having a three-layer structure, which is covered with a shell layer, can also be used. Usually, these core-shell rubber particles are treated as a powder by pulverizing a mass taken out, and the powdery core-shell rubber is often dispersed again in the thermosetting resin composition. However, this method has a problem that it is difficult to stably disperse particles in a state without aggregation, that is, in a state of primary particles.

  To deal with this problem, the core shell rubber particles must be handled in the form of a masterbatch dispersed in primary components in one component of the thermosetting resin, for example, epoxy resin, without having to take it out once in a lump. By using a material that can produce a preferable dispersion state, a preferable dispersion state can be obtained. Such core-shell rubber particles that can be handled in a master batch state can be produced, for example, by the method described in JP-A-2004-315572. In this production method, first, a suspension in which core-shell rubber particles are dispersed is obtained by using a method of polymerizing a core-shell rubber in an aqueous medium represented by emulsion polymerization, dispersion polymerization, and suspension polymerization. Next, an organic solvent showing partial solubility with water, such as a ketone-based solvent such as acetone or methyl ethyl ketone, or an ether-based solvent such as tetrahydrofuran or dioxane is mixed with the suspension, and then mixed with a water-soluble electrolyte such as sodium chloride or chloride. The organic solvent layer and the aqueous layer are phase-separated with potassium, and the aqueous layer is separated and removed to obtain an organic solvent in which core-shell rubber particles obtained are dispersed. Thereafter, after mixing the epoxy resin, the organic solvent is removed by evaporation to obtain a master batch in which the core-shell rubber particles are dispersed in the epoxy resin in the form of primary particles. As the core-shell rubber particle-dispersed epoxy masterbatch produced by such a method, "Kaneace (registered trademark)" commercially available from Kaneka Corporation can be used.

  The content of the core-shell rubber particles is preferably 1 part by mass or more and 10 parts by mass or less, more preferably 1 part by mass or more and 8 parts by mass or less based on 100 parts by mass of the total epoxy resin component. When the amount is 1 part by mass or more, a cured product with high toughness is obtained, and when the amount is 10 parts by mass or less, a cured product with a high elastic modulus is obtained, and the dispersibility of the core-shell rubber particles in the resin is also good. Is preferable.

  As a method of mixing the core-shell rubber particles with the epoxy resin composition, a commonly used dispersion method can be used. For example, a method using a three roll, a ball mill, a bead mill, a jet mill, a homogenizer, a rotation / revolution mixer, or the like can be used. Further, a method of mixing the above-described core-shell rubber particle-dispersed epoxy masterbatch can also be preferably used. However, even if the particles are dispersed in the state of primary particles, re-aggregation may occur due to unnecessary heating or lowering of the viscosity. Therefore, when dispersing and blending the core-shell rubber particles, and mixing and kneading with other components after the dispersion, it is preferable to perform the dispersion at a temperature and viscosity within a range that does not cause reaggregation of the core-shell rubber particles. Specifically, although it depends on the composition, for example, when kneading at a temperature of 150 ° C. or higher, the viscosity of the composition may decrease and aggregation may occur. Therefore, kneading is preferably performed at a lower temperature. However, when the temperature reaches 150 ° C. or higher during the curing process, the temperature can be higher than 150 ° C. because gelation occurs at the time of raising the temperature and reaggregation is prevented.

  In the present invention, when the resin viscosity of the epoxy resin composition at 30 ° C. and 80 ° C. measured by an E-type viscometer is η30, η80 (unit: mPa · s), 200 ≦ η30 / η80 ≦ 500, and 50 ≦ It is necessary to satisfy η80 ≦ 200. When 200 ≦ η30 / η80 ≦ 500, the low-temperature viscosity at −20 ° C. is sufficiently high, the handling during frozen transportation is good, and the normal-temperature viscosity at 25 ° C. is sufficiently high. The movement is suppressed and the curing reaction is suppressed. Therefore, when each component is mixed and the viscosity after stirring for 1 minute is η25 (T0) and the viscosity after standing at 25 ° C for one month is η25 (T1), the viscosity after standing at 25 ° C for one month is The viscosity increase ratio η25 (T1) / η25 (T0) is 1.1 or less, and the viscosity is prevented from increasing for a long time even at room temperature, and the viscosity becomes stable. On the other hand, the viscosity at the resin impregnation temperature at 80 ° C. is sufficiently low, the impregnating property is good, the temperature dependency of the viscosity is high, and contradictory characteristics can be compatible. Further, when η80 is 50 mPa · s or more, the viscosity at the resin impregnation temperature does not become too low, and it is possible to prevent unimpregnated by pits generated by entraining air during injection into the reinforcing fiber base material. When it is 200 mPa · s or less, the viscosity at the resin impregnation temperature is sufficiently low, so that the reinforcing fiber base material has good impregnating properties and can prevent non-impregnation.

  The epoxy resin composition of the present invention preferably has a glass transition temperature Tg of 180 ° C. or higher and 200 ° C. or lower of a cured resin cured at 180 ° C. for 40 minutes. The heat resistance of FRP depends on the glass transition temperature of the cured epoxy resin obtained by curing the epoxy resin composition, and by setting Tg to 180 ° C. or higher, the heat resistance of the cured resin is ensured, and 200 ° C. or lower. By doing so, the curing shrinkage of the epoxy resin composition is suppressed, and the deterioration of the surface quality of the FRP caused by the difference in thermal expansion between the epoxy resin composition and the reinforcing fibers can be prevented. Further, from the relationship between heat resistance and surface quality, the temperature is more preferably 185 ° C or more and 200 ° C or less. As described above, the curing time means the time from when the epoxy resin composition starts to be injected into the molding die to when the demolding starts. Here, the glass transition temperature (Tg) of the cured resin obtained by curing the epoxy resin composition is determined by measurement using a dynamic viscoelasticity measurement (DMA) device. That is, using a rectangular test piece cut out from the cured resin plate, DMA measurement is performed at elevated temperature, and the temperature at the inflection point of the obtained storage elastic modulus G 'is defined as Tg. The measurement conditions are as described in the examples.

  The curability of the epoxy resin composition in the present invention depends on the molding temperature, for example, the vitrification time of the resin composition at 180 ° C., and the shorter the vitrification time of the resin composition at 180 ° C. The curability is high, and the curing time for forming the FRP is also reduced. Therefore, in the RTM method particularly used in the aircraft and automobile fields where productivity is regarded as important, it is preferable that the epoxy resin composition has a vitrification time at 180 ° C. of less than 40 minutes, and it is short. Is more preferable. Here, the vitrification time can be measured as follows. That is, the dynamic viscoelasticity of the epoxy resin composition is measured at a predetermined temperature using a thermosetting measuring device such as ATD-1000 (manufactured by Alpha Technologies), and the complex viscosity is determined from the increase in torque accompanying the progress of the curing reaction. Ask for. At this time, the time until the complex viscosity reaches 1.0 × 107 Pa · s is defined as the vitrification time.

  The reinforcing fiber yarns in the present invention are multifilament yarns such as glass fiber yarns, organic (aramid, PBO, PVA, PE, etc.) fiber yarns, carbon fiber (PAN-based, pitch-based, etc.) yarns and the like. Carbon fibers are excellent in specific strength and specific elastic modulus and hardly absorb water, and therefore are preferably used as reinforcing fibers for aircraft structural materials and automobiles.

  The reinforcing fiber yarn used in the present invention preferably has 3,000 to 50,000 filaments, and particularly preferably 12,000 to 24,000 filaments from the viewpoint of handleability. The form of the reinforcing fiber yarn is not particularly limited, but is preferably a non-twisted yarn having excellent stability in width and thickness of the yarn, and more preferably an opened fiber having excellent fiber orientation.

  Here, the reinforcing fiber base in the present invention is [1]: reinforcing fiber yarn, [2]: reinforcing fiber yarn group in which reinforcing fiber yarns are aligned in parallel, or [3] reinforcing fiber yarn or It is important to form a reinforcing fiber aggregate selected from any one of the reinforcing fiber fabrics composed of the reinforcing fiber yarn group.

  First, [1]: the reinforcing fiber base material 21 made of the reinforcing fiber yarn is prepared using, for example, an apparatus illustrated in FIG. Specifically, the reinforcing fiber yarn 22 pulled out from the bobbin 20 is spread by the spreading unit 201, adjusted to a desired width by the width regulating roller 202, and then slit into a porous resin material 23 previously slit to a desired width. And heated by a heater 203 and pressed by a press roll 204. The fiber opening unit 201 is configured by a vibration roller or the like, and includes a mechanism that applies vibration in a vertical direction or a horizontal direction perpendicular to the traveling direction of the reinforcing fiber yarn 22. Further, the opening unit 201 may include a heater (not shown) for softening the sizing agent attached to the surface of the reinforcing fiber yarn 22. At this time, assuming that the yarn width of the reinforcing fiber yarn 22 drawn out from the bobbin 20 is w0, the width of the reinforcing fiber yarn 22 after opening is widened to w1 (w0 <w1), and then the width regulating roller 202 The width is adjusted to w2 (w1> w2). It is preferable to adjust w2 according to the basis weight required for the reinforcing fiber base 21. In order to improve the width accuracy of the reinforcing fiber base 21, the press roll 204 preferably has a grooved structure.

  The reinforcing fiber substrate 21 produced by such an apparatus has good width and basis weight stability, and also has excellent fiber orientation, so that it can contribute to improvement in the mechanical properties (particularly, compressive strength) of FRP. In addition, it is preferable that the porous resin material 23 be disposed on both surfaces of the reinforcing fiber yarn group because the form stability of the reinforcing fiber base 21 is further improved.

  Next, [2]: a reinforcing fiber base 21 composed of a group of reinforcing fiber yarns is provided with a plurality of bobbins, for example, in an apparatus illustrated in FIG. 20 and the plurality of reinforcing fiber yarns 22 are drawn out while being aligned in parallel. Here, to align in parallel means to align adjacent reinforcing fiber yarns 22 so that they do not substantially intersect or intersect. Preferably, two adjacent reinforcing fiber yarns have a length of 100 mm. When approximating a straight line in the range of the length, the angle is formed so that the angle formed by the approximated straight line is 5 ° or less, more preferably 2 ° or less. Here, approximating the reinforcing fiber yarn 22 to a straight line means forming a straight line by connecting the starting point and the end point of 100 mm. Adjacent reinforcing fiber yarns 22 may be separated from each other at a predetermined interval or may overlap each other according to the required basis weight of the reinforcing fiber base material 21. When a certain interval is provided, the interval is preferably 200% or less of the width of the reinforcing fiber yarn 22, and when they overlap, they may overlap by 100% of the width of the reinforcing fiber yarn 22. It is preferable that the reinforcing fiber yarn group drawn out while being aligned in parallel as described above passes through the fiber opening unit to uniformly distribute the basis weight in the width direction. Further, the reinforcing fiber base 21 made from such a group of reinforcing fiber yarns may be slit if necessary and controlled to an arbitrary width.

  [3] The reinforcing fiber fabric composed of the reinforcing fiber yarns or the group of the reinforcing fiber yarns will be described later.

  As the reinforcing fiber base 22 using the reinforcing fiber yarn 22 and the reinforcing fiber yarn group, an automated fiber placement (AFP) or an automated tape lay-up (ATL) device is suitably used. Such an apparatus is used for the purpose of reducing the disposal rate of the reinforcing fiber base material 21 and automating the laminating process. However, since the width and fiber orientation after placement are strictly required, the morphological stability of the reinforcing fiber base material 21 is important. Become. Here, since the porous resin material 23 used in the present invention has a porous shape, it is excellent in width stability and shape stability by connecting in a plane direction, and thus can be suitably used for AFP and ATL.

  Further, as another embodiment of the reinforcing fiber yarn group in the present invention, there is a sheet-like one arranged in parallel by AFP or ATL. FIG. 3 shows an embodiment of a group of reinforcing fiber yarns used in the present invention. The reinforcing fiber yarns 32 are supplied by an AFP head 300 and are arranged in parallel. A porous resin material (not shown) is disposed on the reinforcing fiber thread group 31 so as to overlap with the reinforcing fiber thread group 31, and is bonded by heating with a far-infrared heater or the like, whereby a reinforcing fiber base material can be obtained. Since the sheet-like reinforcing fiber yarn group 31 arranged by AFP or ATL is not restricted in a direction intersecting with the fiber direction, there is a problem that the form of the reinforcing fiber yarn group 31 is collapsed during transportation. In order to solve such a problem, by arranging and bonding the porous resin material, a binding force in a direction intersecting with the fiber direction is generated, and the problem of conveyance can be solved. The spacing between the reinforcing fiber yarns 32 when the reinforcing fiber yarns 32 are aligned and arranged by AFP or ATL is preferably 0.5 to 2 mm. If the interval is less than 0.5 mm, the resin impregnating property during RTM molding may not be sufficient. If the spacing exceeds 2 mm, when a plurality of reinforcing fiber base materials are laminated, the upper reinforcing fibers fall between the lower reinforcing fiber yarns 32, causing undulation in the thickness direction and causing mechanical properties (particularly compression). Strength) may decrease.

  [3] Reinforcing fiber fabrics composed of reinforcing fiber yarns or a group of reinforcing fiber yarns include woven fabrics (unidirectional, bidirectional, multiaxial), knits, braids, and unidirectionally aligned. Sheet (unidirectional sheet), a multiaxial sheet in which two or more unidirectional sheets are stacked, and the like. A plurality of such reinforcing fiber aggregates may be integrated by various joining means such as a resin such as a stitch thread, a knotting thread, a sack cloth, and a binder. In particular, when used as a structure (especially a primary structure) member of a transportation device (especially an aircraft), a unidirectional sheet, a unidirectional woven fabric, or a multiaxial sheet (especially stitched) is preferable.

  FIG. 4 is a schematic perspective view showing one embodiment of a unidirectional woven fabric 41 as a reinforcing fiber cloth used in the present invention. The reinforcing fiber yarns 42 and the warp auxiliary yarns 43 are arranged in the length direction of the reinforcing fiber assembly 41, that is, the warp direction, and the weft auxiliary yarns 44 thinner than the reinforcing fiber yarns 42 are arranged in the weft direction. This is a unidirectional woven fabric in which the yarn 43 and the weft auxiliary yarn 44 intersect and have the weave structure shown in FIG. It is preferable that the auxiliary yarn 43 has low shrinkage, and examples thereof include glass fiber yarn, aramid fiber yarn, and carbon fiber yarn, and the fineness (weight per unit length) of the auxiliary yarn is reinforced fiber. It is preferably 1/5 or less of the yarn. If it exceeds 1/5, the auxiliary yarn becomes thicker, so that the reinforcing fiber yarn is crimped by the auxiliary yarn, and the strength of the reinforcing fiber is slightly reduced when FRP is formed. On the other hand, from the viewpoint of the form stability and the production stability of the reinforcing fiber aggregate, the fineness of the auxiliary yarn is preferably 0.05% or more of the reinforcing fiber yarn. The fineness within the above range is preferable because the reduction in strength is minimized, and the gap between the reinforcing fiber yarns 42 formed by the warp auxiliary yarns at the time of molding becomes a resin flow path, so that the impregnation of the matrix resin can be promoted.

  FIG. 5 is a schematic perspective view showing one embodiment of a bidirectional woven fabric 51 as a reinforcing fiber fabric used in the present invention. The reinforcing fiber yarns 52 are arranged in the length direction of the bidirectional fabric 51, that is, the warp direction, the reinforcing fiber yarns 53 are arranged in the weft direction, and the warp yarns 52 and the weft yarns 53 intersect with each other. It is a bidirectional fabric having a texture.

  FIG. 6 is a schematic perspective view showing one embodiment of a stitch fabric 61 as a reinforcing fiber fabric used in the present invention. From the lower surface of the stitched fabric 61, a large number of reinforcing fiber yarns are arranged in parallel in the oblique direction to the length direction A to form the + α ° layer 62, and then a large number of reinforcing fibers are strengthened in the width direction of the reinforced fabric. The fiber yarns are arranged in parallel to form a 90 ° layer 63, and then a number of reinforcing fiber yarns are arranged in parallel in an oblique direction to form a −α ° layer 64, and then in the longitudinal direction of the reinforced fabric. A number of reinforcing fiber yarns are arranged in parallel to form a 0 ° layer 65, and in a state where four layers having different arrangement directions are laminated, these four layers are stitched and integrated with a stitch thread 66. I have. Examples of the stitching structure formed by the stitch thread 66 for stitching integration include single-ring stitching and 1/1 tricot knitting. The material of the stitch yarn can be selected from polyester resins, polyamide resins, polyethylene resins, vinyl alcohol resins, polyphenylene sulfide resins, polyaramid resins, and compositions thereof. Among them, a polyester resin and a polyamide resin are preferable. From the viewpoint of the shaping property of the fabric, it is preferable to use a processed yarn of spandex (polyurethane elastic fiber), polyamide resin or polyester resin. The fineness of the stitch yarn is preferably 1/5 or less of the reinforcing fiber yarn in order to suppress crimping of the reinforcing fiber yarn. Further, it is preferably at least 10 dtex, more preferably at least 30 dtex, from the viewpoint of the form stability and the production stability of the reinforcing fiber aggregate. Furthermore, it is preferable that the stitch yarn has elasticity from the viewpoint of shapeability in a preforming step described later. In FIG. 6, the aggregate of the reinforcing fibers whose cross-sectional shape is shown as an ellipse is one yarn, and it looks as if the stitch yarns 66 are arranged between the reinforcing fiber yarns. The aggregate of the reinforcing fibers inserted at random into the reinforcing fiber yarns and shown in an elliptical shape is formed by the constraint of the stitch yarn 66.

  Here, the configuration of the reinforcing fiber of the multiaxial stitch fabric 61 shown in FIG. 6 has been described as a four-layer configuration of + α ° layer / 90 ° layer / −α ° layer / 0 ° layer, but is not limited thereto. Absent. For example, two layers including a 0 ° layer / 90 ° layer, a + α ° layer / −α ° layer, a 0 ° layer / + α ° layer, a + α ° layer / 0 ° layer / −α ° layer, a + α ° layer / −α Layer / 0 ° layer / 0 ° layer / + α ° layer / 0 ° layer / -α ° layer / 90 ° layer / -α ° layer / 0 ° layer / + α ° layer / 0 ° Like a layer, it may include four directions of 0 °, + α °, −α °, and 90 ° such that many 0 ° layers are included. Further, any of 0 °, + α °, −α °, and 90 ° may be included. Note that the bias angle α ゜ is preferably 45 ° from the viewpoint of stacking stitched fabrics in the length direction of the FRP and effectively performing shear reinforcement with reinforcing fibers.

The preferable weight per layer of the reinforcing fiber base in the present invention is in the range of 50 to 800 g / m ² . It is more preferably in the range of 100 to 500 g / m ² , and still more preferably in the range of 120 to 300 g / m ² . If it is less than 50 g / m ² , the number of laminated layers for obtaining a predetermined FRP thickness increases, and the molding workability is poor, which is not preferable. Further, when the basis weight per layer is small, a gap is formed between the reinforcing fiber yarns in the layer and the reinforcing fiber volume ratio Vf becomes partially non-uniform. A large portion has a thicker FRP, and a small reinforcing fiber volume ratio Vf has a thinner FRP, resulting in an FRP having an uneven surface. In such a case, if the reinforcing fiber yarn is spread thinly by a vibrating roller or air jet injection just before weaving, before the integration processing by the stitch yarn, and / or after the processing of the reinforcing fabric, the reinforcing fiber is extended over the entire surface of the reinforcing fabric. Is preferable because the volume ratio becomes uniform and FRP having a smooth surface can be obtained. On the other hand, when it exceeds 800 g / m ² , the impregnating property of the matrix resin is deteriorated, which is not preferable.

  Next, the reinforcing fiber laminate of the present invention will be described. Prior to FRP molding, a plurality of reinforcing fiber substrates are laminated until a desired thickness is reached to form a reinforcing fiber laminate. In the present invention, the reinforcing fiber laminates are preferably integrated by heat fusion or stitching in order to impart handleability and form stability.

  Further, the reinforcing fiber laminate in the present invention, in accordance with the form of the desired fiber-reinforced resin molded article, by giving a three-dimensional shape to the reinforcing fiber laminated substrate using a shaping mold or jig, etc., the shape A fixed preform can also be used. In particular, when the molding die has a three-dimensional shape, by doing so, it is possible to easily suppress the occurrence of fiber turbulence and wrinkles at the time of mold clamping or at the time of resin injection / impregnation.

  Next, the FRP of the present invention will be described. The FRP of the present invention is obtained by impregnating the above-mentioned reinforcing fiber laminate with a matrix resin. Such a matrix resin is solidified (cured or polymerized) as necessary. Preferable examples of such a matrix resin include, for example, a thermosetting resin, a thermoplastic resin for RIM (Reaction Injection Molding) and the like. Among them, an epoxy resin, a phenol resin, a vinyl ester resin, and an epoxy resin, which are suitable for injection molding. It is preferably at least one selected from a saturated polyester resin, a cyanate ester resin, a bismaleimide resin and a benzoxazine resin. In the present invention, a specific epoxy resin composition is particularly used.

  Further, since the FRP of the present invention has excellent mechanical properties and is light in weight, its use is intended for primary structural members, secondary structural members, exterior members or interior members in any of aircraft, automobiles and marine transportation equipment. It is preferred that

  Next, a method of forming an FRP using the reinforcing fiber base in the present invention will be described.

  Among the reinforcing fiber bases in the present invention, the reinforcing fiber bases composed of the reinforcing fiber yarns and the group of the reinforcing fiber yarns are arranged in a desired shape by an AFP or ATL device.

  Such an arrangement step may be performed in a two-dimensional plane shape, or may be performed in a three-dimensional shape. In the case of a two-dimensional planar shape, after arranging the reinforcing fiber base material for each layer, a porous resin material is arranged and bonded to form a sheet-like reinforcing fiber base material that can be easily transported for each layer. It can be created and can be transported to a separately prepared shaping mold without breaking the shape of the aligned and arranged state. At this time, it is preferable that the porous resin material to be disposed has at least a partial cut, because the shapeability in a preforming step described later becomes better. Further, as the transport means, a transport means using a method such as static electricity, suction, or needle sticking can be used.

  Further, the sheet-like reinforcing fiber base material prepared for each layer may be a reinforcing fiber laminate in which a plurality of layers are stacked and integrated by heat fusion or stitching in order to further improve the handleability. At this time, by setting the arrangement direction of the reinforcing fiber base material of the nth layer after the second layer to a direction different from the arrangement direction of the (n-1) th layer, the reinforcement of a plurality of layers that can be handled in the same manner as a fabric It can be a fiber laminate. The step of integrating the reinforcing fiber bases may be performed on the entire surface where the reinforcing fiber bases overlap, or may be partially performed. When integrated over the entire surface, the reinforced fiber substrate has excellent shape stability. On the other hand, if they are partially integrated, they are likely to be deformed (that is, have good shapeability) during shaping into a molded product shape in a preforming step described later. Therefore, it is preferable to use these arbitrarily depending on the complexity of the shape of the molded product.

  Here, the reinforcing fiber base in the present invention is formed by adding a porous resin to a reinforcing fiber yarn group in which reinforcing fiber yarns (with no resin material attached) are arranged in a desired shape by an AFP or ATL device. It can also include one in which materials are arranged and bonded. This makes it possible to impart properties such as impact resistance to carbon fiber yarns having no properties such as impact resistance.

  Furthermore, after arranging the first-layer reinforcing fiber base material, the arrangement of the second and subsequent layers may be repeated on the same plane. In this arrangement step, a heater is provided in the head portion of the AFP or ATL apparatus, and the second and subsequent layers of the reinforcement fiber base are arranged while melting the resin material on the surface of the reinforcement fiber base. And the integration process can be integrated. At this time, by setting the arrangement direction of the reinforcing fiber base material of the nth layer after the second layer to a direction different from the arrangement direction of the (n-1) th layer, the reinforcement of a plurality of layers that can be handled in the same manner as a fabric It can be a fiber laminate.

  Further, among the reinforcing fiber substrates in the present invention, the reinforcing fiber substrate comprising a reinforcing fiber aggregate, and the reinforcing fiber laminate including a resin material between layers of the reinforcing fiber yarn group have a desired shape in accordance with the shape of a molded product. Used for cutting.

  The reinforcing fiber base material or the reinforcing fiber laminate thus formed is laminated one by one or a plurality of layers at a desired angle configuration, and then a preforming step is performed to form a preform. In the preforming step, it is desirable to heat the resin material in the range of -30 ° C to + 5 ° C. If the heating temperature is low, the resin material is not sufficiently softened, and the shape of the preform may not be fixed. In addition, when the heating temperature is high, the resin material penetrates the reinforcing fiber base material, and the impregnation property of the matrix resin may deteriorate.

  The molding of the FRP of the present invention is performed by so-called resin injection molding, and RTM (Resin Transfer Molding) molding or VaRTM (Vacuum assisted Resin Transfer Molding) molding is preferably applied. The porous resin material disposed on at least one surface of the reinforcing fiber base in the present invention has a function as a flow path (air path) when discharging air inside the reinforcing fiber base and a function as a resin diffusion medium. Demonstrate. Therefore, it is possible to improve the internal quality of the molded product and to speed up the resin injection process. In addition, since the porous resin material disposed on at least one side of the reinforcing fiber base in the present invention has a connection in a planar direction, it is possible to prevent deformation of the reinforcing fiber base when resin is injected at a high pressure.

The FRP of the present invention has a reinforcing fiber volume content (Vf) in the range of 53 to 65%, and has a room temperature compressive strength of 240 MPa or more after impact application described in SACMA-SRM-2R-94. preferable. In addition, Vf (unit is vol%) indicates a volume ratio occupied by the reinforcing fibers in the fiber reinforced resin, and is specifically defined by the following formula, and the symbols used here are as shown below.
Vf = (W × 100) / (ρ × T)
W: Weight of reinforcing fiber per 1 cm ² of reinforcing fiber substrate (g / cm ² )
ρ: density of reinforcing fiber (g / cm ³ )
T: thickness of fiber reinforced resin (cm)

  When the Vf of the fiber reinforced resin is in the range of 53 to 65%, the excellent mechanical properties of the fiber reinforced resin can be maximized. If Vf is less than 53%, the effect of reducing the weight is inferior, and if it exceeds 65%, the above-mentioned injection molding becomes difficult, and the mechanical properties (particularly, impact resistance) may decrease. That is, in such a Vf range, when the room-temperature compressive strength after impact application described in SACMA-SRM-2R-94 of the fiber-reinforced resin is 240 MPa or more, a material that satisfies both the weight-reducing effect and the mechanical properties can be obtained. can do. Fiber reinforced resins satisfying such requirements are used in a wide variety of applications because of their excellent mechanical properties and lightening effects. Although it is not particularly limited, it is used as a primary structural member, a secondary structural member, an exterior member, an interior member, or a part thereof in a transportation device such as an aircraft, an automobile, or a ship, and the effects are maximized.

  Note that SACMA is an abbreviation for Suppliers of Advanced Composite Materials Association, and SACMA-SRM-2R-94 is a test method standard defined here. Cold compressive strength after impact is measured at an impact energy of 270 in-lb under Dry conditions according to SACMA-SRM-2R-94.

  Hereinafter, the present invention will be further described using examples. Raw materials and molding methods used in Examples and Comparative Examples are as follows. The present invention is not limited to these Examples and Comparative Examples.

[Example 1]
<Reinforcing fiber yarn>
PAN-based carbon fiber, 24,000 filaments, tensile strength: 6.0 GPa, and tensile modulus of elasticity: 294 GPa were used as carbon fiber yarns.

<Resin material>
It was prepared and polymerized so that polyamide 6 was 20 mol% and polyamide 12 was 80 mol%. The melting point was 150 ° C.

<Porous resin material>
The resin material was formed into a nonwoven fabric by a melt blow device. The basis weight was 10 g / m ² .

<Matrix resin>
80 parts by weight of tetraglycidyl diaminodiphenylmethane type epoxy (“Araldite (registered trademark)” MY-721, manufactured by Huntsman Japan KK), bisphenol F type epoxy resin (“Epiclon (registered trademark)” 830, manufactured by DIC Corporation) ) 20 parts by weight and 70 parts by weight of 4,4′-methylenebis (2-isopropyl-6-methylaniline) (“Lonacure (registered trademark)” M-MIPA (manufactured by Lonza Co., Ltd.) The mixture was stirred for 1 hour to be uniformly dissolved.

<Reinforcing fiber substrate>
Using the apparatus shown in FIG. 2, a 1/4 inch wide tape-like reinforcing fiber substrate was prepared. The basis weight of the reinforcing fiber base was 162 g / m ² .

<Reinforced fiber laminate>
Such a reinforcing fiber substrate is quasi-isotropically laminated [45/0 / -45 / 90] _3S (24 layers: “3S” here is symmetrical to that laminated in the order of the orientation angles shown in []) with an AFP device. [Symmetry] arrangement, and a single set (4 layers × 2 = 8 layers) is formed, and three sets of these sets (8 layers × 3 = 24 layers) are shown. The same applies hereinafter.) After laminating on a preform mold having the above structure, it was heated in an oven at the same temperature as the melting point of the resin material for 1 hour in a state where the bag was sealed with a bag film and a sealant and the pressure was reduced to a vacuum. Thereafter, the preform was taken out of the oven, cooled to room temperature, and then released to obtain a reinforced fiber laminate.

<Fiber reinforced resin>
A resin diffusion medium (aluminum wire mesh) is laminated on the obtained reinforcing fiber laminate, and a cavity is formed by sealing a flat molding die and a bag material with a sealant, and forming the cavity in a 100 ° C. oven. I put it. After the temperature of the reinforcing fiber laminate reached 100 ° C., the closed cavity was evacuated to a vacuum, and the matrix resin was injected at only a pressure difference from the atmospheric pressure while maintaining the temperature at 100 ° C. After the impregnation with the resin, the temperature was raised to 180 ° C. while continuing the reduced pressure, and left for 2 hours to cure and release the mold. The obtained FRP had a Vf of 62% and a CAI of 278 MPa.

[Example 2]
The procedure was carried out except that the mixing ratio of the resin materials was changed and the polyamide 6 was adjusted to 20 mol%, the polyamide 6-6 to 15 mol%, the polyamide 6-10 to 15 mol%, and the polyamide 12 to 50 mol% and polymerized. In the same manner as in Example 1, an FRP plate 2 was prepared. The melting point of the obtained resin material was 120 ° C., Vf of FRP was 63%, and CAI was 258 MPa.

[Example 3]
The reinforcing fiber yarn to which the porous resin material is not adhered is drawn into a two-dimensional planar shape using an AFP device to form a reinforcing fiber yarn group, and after the porous resin material is arranged thereon, By heating and bonding with an infrared heater, a planar reinforcing fiber substrate was prepared. The basis weight of the reinforcing fiber base was 162 g / m ² .
Example 1 was repeated except that the reinforcing fiber base material was conveyed layer by layer and laminated on a planar preform mold in a configuration of pseudo isotropic lamination [45/0 / -45 / 90] _3S (24 layers). In the same manner as in the above, an FRP flat plate 3 was prepared. The obtained FRP had a Vf of 61% and a CAI of 276 MPa.

[Example 4]
A unidirectional woven fabric as shown in FIG. 4 was prepared using a reinforcing fiber yarn and an auxiliary yarn (“ECE225 1/0 1Z”, manufactured by Unitika Ltd.), and a porous resin material was arranged on one surface thereof. Thereafter, the mixture was heated and bonded by a far-infrared heater to produce a bonded reinforcing fiber substrate. The basis weight of the reinforcing fiber base was 190 g / m ² .
An FRP flat plate was prepared in the same manner as in Example 1 except that such a reinforcing fiber substrate was laminated on a planar preform mold in a configuration of pseudo isotropic lamination [45/0 / -45 / 90] _3S (24 layers). 4 was created. The obtained FRP had a Vf of 58% and a CAI of 262 MPa.

[Example 5]
Using a reinforcing fiber thread and a stitch thread ("Grilon (registered trademark) K-140" 75 dtex, manufactured by Ms. Chemie Japan Co., Ltd.), arranging a porous resin material between the layers and the lowermost layer, and then suturing with the stitch thread By doing so, a two-layer reinforced fiber substrate of [45 / -45] was prepared. The basis weight of the reinforcing fiber substrate was 268 g / m ² .
An FRP flat plate was prepared in the same manner as in Example 1 except that such a reinforcing fiber base was laminated on a planar preform mold in a configuration of pseudo isotropic lamination [45 / -45 / 0/90] _3S (24 layers). 5 was created. The VRP of the obtained FRP was 60%, and the CAI was 259 MPa.

[Example 6]
An FRP flat plate 6 was prepared in the same manner as in Example 1 except that the mixing ratio of the resin material was changed and the polyamide 6 was adjusted to 80 mol% and the polyamide 6-6 to 20 mol% and polymerized. The melting point of the obtained resin material was 195 ° C., the Vf of FRP was 56%, and the CAI was 245 MPa.

[Comparative Example 1]
A reinforcing fiber base material was prepared in the same manner as in Example 3 except that the form of the resin material was changed to powder, but the sheet-like reinforcing fiber yarn group aligned with AFP was separated during transportation, A molded article could not be obtained.

[Comparative Example 2]
An FRP flat plate 7 was prepared in the same manner as in Example 1 except that polyamide 6-6 (independent component) was used as the resin material. The Vf of FRP was 53% and the CAI was 196 MPa.

  Since the FRP of the present invention has excellent mechanical properties and is lightweight, its use is limited to primary structural members, secondary structural members, exterior members or interior members in any of aircraft, automobiles, and marine transport equipment. It is also suitable for members for general industrial use such as medical equipment such as a windmill blade, a robot arm and an X-ray top.

11: Reinforced fiber substrate 12: Reinforced fiber aggregate 13: Resin material 20: Bobbin 21: Reinforced fiber substrate 22: Reinforced fiber thread 23: Porous resin material 201: Spreading unit 202: Width regulating roller 203: Heater 204: press roll 31: reinforcing fiber yarn group 32: reinforcing fiber yarn 300: AFP head 41: unidirectional woven fabric 42: reinforcing fiber yarn (warp)
43: auxiliary yarn (warp)
44: auxiliary yarn (weft)
51: bidirectional fabric 52: reinforcing fiber yarn (warp)
53: Reinforcing fiber yarn (weft)
61: Stitched fabric 62: Reinforced fabric forming + α ° reinforcing fiber layer 63: Reinforced fabric forming 90 ° reinforcing fiber layer 64: Reinforced fabric forming -α ° reinforcing fiber layer 65: Reinforced fabric formed 0 ° reinforcing fiber layer 66: stitch yarn

Claims (10)

A fiber reinforced resin formed by impregnating a reinforcing fiber base material with an epoxy resin composition and curing by heating,
[1] The reinforcing fiber base material is (a): a reinforcing fiber yarn, (b): a group of reinforcing fiber yarns in which reinforcing fiber yarns are aligned in parallel, (c): (a) or (b) The reinforcing fiber fabric selected from the group consisting of polyamide 6, polyamide 6-6, polyamide 6-10, polyamide 12, and polyamide 6-I. Consisting of a reinforcing fiber base material in which a porous resin material made of a copolyamide containing one polyamide component is arranged,
[2] The epoxy resin composition comprises an epoxy resin and a curing agent, and contains not less than 70 parts by mass and not more than 100 parts by mass of tetraglycidyldiaminodiphenylmethane [A] based on 100 parts by mass of all epoxy resin components. , 4,4'-methylenebis (2-isopropyl-6-methylaniline) [B] is contained in an amount of 80 parts by mass or more and 100 parts by mass or less based on 100 parts by mass of all the curing agent components, and at 30 ° C and 80 ° C. A resin viscosity of η30, η80 (unit: mPa · s), wherein the fiber reinforced resin comprises an epoxy resin composition satisfying 200 ≦ η30 / η80 ≦ 500 and 50 ≦ η80 ≦ 200. .   The fiber-reinforced resin according to claim 1, wherein the porous resin material has a content of 1 to 20% by weight based on the reinforcing fiber base material.   The fiber reinforced resin according to claim 1, wherein the porous resin material is in a nonwoven fabric shape, and has a fiber diameter of 1 to 100 μm.   The fiber reinforced resin according to any one of claims 1 to 3, wherein a composition ratio of the polyamide 12 in the porous resin material is in a range of 5 mol% or more and less than 99 mol%.   The fiber reinforced resin according to any one of claims 1 to 4, wherein the reinforcing fiber yarn group is a sheet-like shape in which a plurality of reinforcing fiber yarns are aligned in parallel.   The fiber-reinforced resin according to any one of claims 1 to 4, wherein the reinforcing fiber yarn group is a sheet-like shape in which reinforcing fiber yarns are arranged in parallel by an automated fiber placement device.   The reinforcing fiber aggregate is a group of reinforcing fiber yarns in which reinforcing fiber yarns are arranged in parallel in one direction, and extends in a direction intersecting with the reinforcing fiber yarns. The fiber reinforced resin according to any one of claims 1 to 4, wherein the fiber reinforced resin is a unidirectional woven fabric composed of a group of auxiliary fiber yarns that is 1/5 or less.   The said reinforcing fiber aggregate is a bidirectional woven fabric composed of the reinforcing fiber yarn group arranged in one direction and the reinforcing fiber yarn group arranged in one direction in different directions. 5. The fiber-reinforced resin according to any one of items 4 to 4.   At least two layers of the reinforcing fiber cloth, the reinforcing fiber yarn group arranged in one direction and the reinforcing fiber yarn group arranged in one direction in different directions, are cross-laminated, and the fineness is reinforced fiber yarn. The fiber-reinforced resin according to any one of claims 1 to 4, which is a stitched fabric stitched and integrated by an auxiliary fiber thread group that is 1/5 or less of the thread.   The reinforcing fiber volume content is in the range of 53 to 65%, and the room-temperature compressive strength after impact imparting described in SACMA-SRM-2R-94 is 240 MPa or more. Fiber reinforced resin.

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