JP2015078310A - Prepreg - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a composite material having excellent mechanical properties by having a good impregnation property of a matrix resin composition, exhibiting a high flow of the matrix resin at the time of molding, and suppressing a decrease in strength of the molded product due to an increase in the thickness of the molded product. Get well. SOLUTION: A sheet in which a plurality of tow-like carbon fiber yarns made of carbon fibers having a single fiber fineness of 1.2 to 2.4 dtex are arranged in parallel to each other, and one or both sides of the sheet Reinforced fiber base material composed of auxiliary yarns arranged at an angle different from that of the carbon fiber yarns, or a plurality of similar sheets were laminated with angles different from each other in the arrangement direction of the respective sheets, and integrated with stitch yarns A prepreg obtained by impregnating a reinforcing fiber stitch base material with a thermosetting matrix resin composition. [Selection figure] None

Description

  The present invention relates to a carbon fiber prepreg. The present invention particularly relates to a carbon fiber prepreg having handleability suitable for a large molded article and excellent strength development.

Since carbon fibers have high specific strength and specific elastic modulus, fiber reinforced composite materials impregnated with a matrix resin using the carbon fibers as reinforcing fibers have excellent mechanical properties and light weight. -In addition to space applications, it is being widely deployed in general industrial applications such as automobiles, civil engineering / architecture, pressure vessels, and windmill blades, and there is a strong demand for higher performance. In particular, the application of fiber reinforced composite materials to large structural members has been promoted in recent years. From the progress of member design technology using fiber reinforced composite materials, the demand for manufacturing cost reduction by reducing the number of members and the progress of integrated molding technology to meet the demand, molding The trend of increasing body size is becoming stronger.

As a method for forming a fiber-reinforced composite material, there is a method using a prepreg formed by impregnating reinforcing fibers mainly with a matrix resin of a thermosetting resin. The fiber reinforced composite material is formed by laminating a prepreg and then heating or heating / pressing the prepreg to cure a thermosetting resin that is a matrix resin. The technique using a prepreg is superior to the VaRTM method and the like in terms of the strength utilization rate of the fiber. Therefore, this prepreg is often used in general industrial applications.

When molding a large molded article, it is generally desired that the matrix resin has a high flow. If the matrix resin has a low flow, voids in the molded body are likely to occur. However, when the matrix resin has a high flow, voids are reduced, but microundulation of fibers occurs, and mechanical properties of a large-sized molded product are deteriorated. The mechanical properties of large molded products are highly dependent on thickness, and the compression strength tends to decrease as the thickness of the molded products increases. Patent Documents 1 and 2 propose to prevent deterioration of physical properties by making the matrix resin low flow. However, when this technology is applied to molding a large molded product, defects such as voids are generated. It is a problem.

As the prepreg, a unidirectional material (UD material) in which continuous fibers are aligned in one direction as a reinforcing fiber, a woven fabric, a knitted fabric, a non-woven fabric, or the like is used. Among them, the UD material prepreg has high strength and elastic modulus along the fiber direction, and is often used for structural materials such as aircraft, ships and windmills. On the other hand, textile prepregs are widely applied because they are excellent in formability and design of shapes having complicated curved surfaces, and exhibit a certain degree of strength not only in the vertical and horizontal directions but also in the middle direction. However, since a normal woven fabric has a woven structure in which reinforcing fiber yarns are arranged in two directions, warping and weft yarns are bent (crimped) at the intersection of warp and weft yarns. Since the straightness of the fiber is lowered, generally, when the woven prepreg is used, the mechanical properties tend to be inferior compared with the case where the UD material prepreg is used.

As a means of reducing the crimps of reinforcing fiber yarns, there is a satin weave structure in which the number of crossing points between yarns is reduced. With this structure, crimping of the weaving yarn can be reduced and high strength can be expected, but this fabric is prone to deformation due to tension during prepreg production, and there is a difference between the front and back of the woven structure. There is a problem that warpage due to curing shrinkage of the resin occurs in the molded product.

As one means for solving such a problem, NCF (Non-crimp fabric) made by stitch yarns in a state where a plurality of layers of reinforcing fiber groups arranged in parallel in one direction are laminated at different angles. The use is drawing attention. NCF can reduce the crimp of reinforced fibers, improve the mechanical properties of the resulting fiber reinforced composite material, and can produce prepregs that have a laminated structure such as quasi-isotropy in a single sheet. Therefore, it is expected to be a base material that can realize cost reduction of the fiber reinforced composite material as compared with woven fabrics and knitted fabrics.

In Patent Document 3, a plurality of sheets in which a plurality of tow-shaped carbon fiber yarns are arranged in parallel with each other, the carbon fiber arrangement direction of each sheet has an angle different from the reference direction. A technique related to a multi-axis stitch base material integrated with stitch yarns in a laminated state is described, and carbon fibers that are inexpensive and reinforcing fibers are uniformly dispersed from this base material and matrix resin. It is said that a reinforced fiber composite material can be obtained. However, in reinforcing fiber base materials such as multi-axis stitch base materials and woven fabrics composed of carbon fibers interlaced, the friction between the fibers at the crossing point greatly affects the uniformity of the reinforcing fiber base materials. If the slip at the point is bad or non-uniform, there is a problem that defects such as opening of the eyes and uneven thickness occur.

JP-A-1-161040 JP-A-2-169658 Japanese Patent No. 4534409

The present invention provides a reinforcing fiber comprising a sheet in which a plurality of tow-like carbon fiber yarns are arranged in parallel to each other, and auxiliary yarns arranged on one or both sides of the sheet at an angle different from that of the carbon fiber yarn. A prepreg formed by impregnating a matrix resin into a base material, or a plurality of sheets of tow-like carbon fiber yarns arranged in parallel with each other, an arrangement of carbon fiber yarns included in each sheet An object of the present invention is to provide a prepreg formed by impregnating a matrix resin into a reinforcing fiber stitch base material integrated with stitch yarns in a state where the directions are laminated at different angles. In addition, the matrix resin has good impregnation, the matrix resin exhibits high flowability during molding, and the reduction in strength of the molded product due to the increase in the thickness of the molded product is suppressed. The object is to provide a well-obtained prepreg. It is another object of the present invention to provide a prepreg that has excellent handling properties such as stiffness, shape stability, formability, and tackiness when laminated, and has an excellent appearance with no irregularities in the substrate.

The first gist of the present invention is a sheet in which a plurality of tow-like carbon fiber yarns composed of carbon fibers having a single fiber fineness of 1.2 to 2.4 dtex are arranged in parallel with each other; It is a prepreg formed by impregnating a thermosetting matrix resin composition into a reinforcing fiber base composed of auxiliary yarns arranged on one side or both sides of a sheet at an angle different from that of the carbon fiber yarn.
The second gist of the present invention is a sheet in which a plurality of tow-like carbon fiber yarns made of carbon fibers having a single fiber fineness of 1.2 to 2.4 dtex are arranged in parallel to each other. A plurality of carbon fiber yarns included in each sheet are laminated at different angles from each other, and a reinforcing fiber stitch base material integrated with stitch yarns is impregnated with a thermosetting matrix resin composition. It is a prepreg.

According to the present invention, the fiber-reinforced composite has excellent mechanical properties, with excellent matrix resin impregnation, high flowability of the matrix resin during molding, and reduced strength reduction of the molded product due to an increase in the thickness of the molded product. Materials can be obtained with good productivity. Moreover, it is excellent in handling properties such as stiffness, shape stability, moldability, tackiness at the time of lamination, and the like, and a prepreg having an excellent appearance with no irregularities in the substrate can be obtained.

The prepreg of the present invention includes a sheet in which a plurality of tow-like carbon fiber yarns made of carbon fibers having a single fiber fineness of 1.2 to 2.4 dtex are arranged in parallel to each other, and one side of the sheet Or it is preferable that it is a prepreg which impregnates the thermosetting matrix resin composition in the reinforced fiber base material which consists of an auxiliary | assistant thread | yarn arrange | positioned on the both sides with the angle different from the said carbon fiber yarn. Or, a plurality of sheets of tow-like carbon fiber yarns made of carbon fibers having a single fiber fineness of 1.2 to 2.4 dtex are arranged in parallel with each other, and included in each sheet The carbon fiber yarn is preferably a prepreg formed by impregnating a reinforcing fiber stitch base material, which is laminated at different angles with each other, and integrated with stitch yarns, with a thermosetting matrix resin composition.

  In the prepreg of the present invention, it is preferable that the reinforcing fiber used for the prepreg is a carbon fiber having a roundness of 0.7 to 0.9 in a cross-sectional shape perpendicular to the fiber axis of the single fiber.

In the prepreg of the present invention, the reinforcing fiber used in the prepreg is preferably a carbon fiber having a diameter Di of a cross section perpendicular to the fiber axis of the single fiber of 8 μm or more and 20 μm or less.

The prepreg of the present invention is preferably a carbon fiber prepreg in which the thermosetting matrix resin composition is an epoxy resin composition.

The prepreg of the present invention comprises reinforcing fibers, a thermosetting matrix resin composition, and stitch yarns or auxiliary yarns.

(Reinforced fiber)
The carbon fiber of the prepreg of the present invention is not particularly limited, but PAN (polyacrylonitrile) carbon fiber and pitch carbon fiber are used. Desirably, PAN-based carbon fiber is used. One type of carbon fiber may be used, or a plurality of types may be used in a single prepreg.

  The reinforcing fibers constituting the prepreg of the present invention are carbon fibers having an average single fiber fineness of 1.0 dtex or more. When the average single fiber fineness is less than 1.0 dtex, the impregnated state of the matrix resin composition is deteriorated, so that it is not used in the present invention. When the average single fiber fineness is 1.2 dtex or more, the impregnation state is further improved, which is preferable.

Further, when the average single fiber fineness is less than 1.0 dtex, the straightness of the reinforcing fiber is lost due to the influence of the resin flow generated when molding a large molded product, and the strength of the molded product can be low. It is not used in the invention. When the average single fiber fineness is 1.2 dtex or more, since the straightness of the fiber is maintained even if the resin flow at the time of molding a large-sized molded product is large, a molded product with high strength can be obtained.

  Further, the reinforcing fibers constituting the carbon fiber prepreg of the present invention have an average single fiber fineness of 2.4 dtex or less. When the average single fiber fineness exceeds 2.4 dtex, the strength and elastic modulus of the fiber tend to be low. Accordingly, in the present invention, those having an average single fiber fineness of 2.4 dtex or less are used.

A fiber reinforced composite material obtained by laminating a prepreg having a basis weight of 300 g / m ² of a reinforcing fiber using carbon fibers having an average single fiber fineness of less than 1.0 dtex to form a molded flat plate having a thickness of about 10 mm, and a thickness of about 20 mm. Comparing the compressive strength of the reinforced fiber composites laminated and molded so as to form a molded flat plate, the properties of the molded body having a thickness of about 20 mm are lower than those of the molded body having a thickness of about 10 mm. In the case of a prepreg using a carbon fiber having a thickness of 1.0 dtex or more, there is almost no difference in physical properties between a molded body having a thickness of about 20 mm and a molded body having a thickness of about 10 mm.

In the case of a prepreg obtained by impregnating a matrix resin having a relatively low resin viscosity into a reinforcing fiber base made of carbon fibers having an average single fiber fineness of less than 1.0 dtex, the basis weight of the reinforcing fiber base is 150 g / m ^2. , 300 g / m ² , 600 g / m ² prepreg laminated and molded to form a molded flat plate having a thickness of about 10 mm, tend to show lower strength as the basis weight of the reinforcing fiber base increases However, in the case of a prepreg using carbon fibers having an average single fiber fineness of 1.0 dtex or more, there is almost no difference in strength even if the basis weight of the reinforcing fiber base is large.

Further, the carbon fiber yarns preferably have a roundness of a cross-sectional shape perpendicular to the fiber axis of the single fiber of 0.7 to 0.9. When the roundness is 0.7 or more and 0.9 or less, the carbon fiber content of the fiber-reinforced composite material can be increased, and the mechanical properties can be improved. Here, the roundness is a value obtained by the following formula (I), and S is a cross-sectional area of a single fiber obtained by SEM observation and image analysis of a cross section perpendicular to the fiber axis of the single fiber. Yes, L is the length of the circumference of the cross section of the single fiber obtained in the same manner.
Roundness = 4πS / L ² (I)

The single fiber of the carbon fiber yarn has a plurality of groove-shaped bumps extending in the longitudinal direction on the surface, and the height difference between the highest part and the lowest part in the range of the peripheral length of the single fiber is 2 to 80 nm. It is desirable that If the height difference is smaller than 10 nm, the impregnation property of the matrix resin composition may be deteriorated, and the effect of the present invention is reduced. Further, if the height difference is larger than 80 nm, the convergence property of the carbon fiber yarn tends to be lowered, and the mechanical properties of the fiber-reinforced composite material may be lowered.

  The reinforcing fiber used in the prepreg of the present invention preferably has a diameter Di of a cross section perpendicular to the fiber axis of the single fiber of 8 μm or more. In prepreg production, the flow during impregnation and molding of the matrix resin composition occurs when the resin passes through the voids between the single fibers, so the size of the voids formed by the single fibers affects the impregnation and resin flow. give. When the diameter Di is less than 8 μm, the gap between the single fibers is reduced, so that the impregnation property is lowered and the prepreg is poorly impregnated. When the diameter Di is 9 μm or more, the impregnation property is further improved, which is further preferable. When the diameter Di is 10 μm or more, it is particularly preferable.

Further, the diameter Di of the single fiber is preferably 20 μm or less. As described above, when the diameter of the single fiber is increased, there is a problem that the strength of the reinforcing fiber is limited to a low one. In addition, the diameter Di of the single fiber said to this invention is the long diameter (maximum ferret diameter) of the fiber cross section obtained by SEM observation and image-analyzing the shape of a cross section perpendicular | vertical to the fiber axis of a single fiber.

(Reinforced fiber substrate)
In the prepreg of the present invention, a reinforcing fiber substrate in which a sheet in which a plurality of tow-like carbon fiber yarns are arranged in parallel to each other is prevented from being unwound by an auxiliary yarn, or a plurality of the sheets is desired. A reinforcing fiber stitch base material integrated with stitch yarn in a state of being laminated at an angle is used.

  The lamination angle of the sheet constituting the reinforcing fiber stitch base material can be selected at any angle, and the arrangement direction of the carbon fiber yarns included in the sheet is, for example, based on the direction in which the reinforcing fiber stitch base material continues. It can be selected from 0 °, ± 30 °, ± 45 °, ± 60 °, and 90 °. Moreover, it is preferable that the angle which each sheet | seat makes after lamination | stacking becomes symmetrical on the basis of the direction where a reinforced fiber stitch base material continues.

<Auxiliary yarn or stitch yarn>
The auxiliary yarn or stitch yarn used for the reinforcing fiber base or the reinforcing fiber stitch base used in the present invention may be any material, for example, a yarn made of polyester resin, polyamide resin, polyolefin resin, vinylon fiber, Carbon fiber, glass fiber, aramid fiber, and the like can be selected. For example, a composite yarn in which low melting point resin fibers are aligned and covered with glass fibers may be used.

In the reinforcing fiber base or reinforcing fiber stitch base used in the present invention, resin powder is dispersed and heated, if necessary, and fused, or a grid made of resin fibers such as polyester and polyamide is arranged and heated. By fusing, desired shape maintenance property and drape property can be imparted.
The reinforcing fiber base or the reinforcing fiber stitch base used in the present invention can be manufactured by using a multi-axis weft insertion type knitting machine manufactured by LIBA, Karl Mayer, etc. of Germany, not a loom.

On the other hand, woven fabrics such as plain weave, twill weave and satin weave have a crimp at the intersection where warp and weft intersect, and after becoming a fiber reinforced composite material, due to stress concentration caused by the bending, etc. Decreasing the physical properties of the fiber-reinforced composite material is the reason why NCF is superior. A warp-shaped unidirectional woven fabric in which wefts having a relatively small basis weight are driven at a constant pitch with respect to the warp, for example, 225 dtex glass fiber is driven at a pitch of about 3 mm into a warp of 600 g / m 2 has almost no warp bending. Can be woven. The reinforcing fiber base material that can be used in the present invention includes such a unidirectional fabric in which the reinforcing fiber is not bent.

(Matrix resin composition)
The matrix resin composition resin composition contained in the prepreg of the present invention contains an epoxy resin, an epoxy resin curing agent, and other additional components.

<Epoxy resin>
The epoxy resin contained in the matrix resin composition contained in the prepreg of the present invention is, for example, any of the glycidyl ether type, glycidyl amine type, glycidyl ester type, and alicyclic epoxy type, or these types. A compound in which two or more types of epoxy groups selected from are present in the molecule can be used.

  Specific examples of the glycidyl ether type epoxy resin include bisphenol A type epoxy resins (for example, “jER826”, “jER1001”, “EPON825”, “jER826”, “jER828”, “jER828”, “JER828” manufactured by Mitsubishi Chemical Corporation) jER1001 "," Epiclon 850 "manufactured by DIC Corporation," Epototo YD-128 "manufactured by Nippon Steel Chemical Co., Ltd.," DER-331 "," DER-332 "manufactured by Dow Chemical Co., etc.) Bisphenol F type epoxy resin (for example, “jER806”, “jER807”, “jER1750” manufactured by Mitsubishi Chemical Corporation, “Epicron 830” manufactured by DIC Corporation, “Epototo YD-170” manufactured by Nippon Steel Chemical Co., Ltd. , “Epototo YD-175”, etc.), Lucinol type epoxy resin (for example, “Denacol EX-201” manufactured by Nagase ChemteX Corporation), phenol novolac type epoxy resin (eg “jER152”, “jER154” manufactured by Mitsubishi Chemical Corporation, DIC Corporation) "Epiclon 740" manufactured by Huntsman Advanced Materials Co., Ltd., "EPN179" and "EPN180" manufactured by Huntsman Advanced Materials Co., Ltd.), ethylene glycol or polyethylene glycol type epoxy resin (for example, "Denacol manufactured by Nagase ChemteX Corporation") EX810 ”,“ Denacol EX-861 ”,“ Epolite 200E ”manufactured by Kyoeisha Chemical Co., Ltd.), propylene glycol or polypropylene glycol type epoxy resin (for example, manufactured by Nagase ChemteX Corporation) "Denacol EX-911", "Denacol EX-941", "Denacol EX-920", "Denacol EX-921", "Denacol EX-931", "Epolite 70P", "Epolite 200P" manufactured by Kyoeisha Chemical Co., Ltd. ”,“ Epolite 400P ”,“ Epolide NT228 ”manufactured by Daicel Corporation), naphthalenediol type epoxy resin (for example,“ Epototo ZX-1355 ”manufactured by Nippon Steel Chemical Co., Ltd., etc.) , Isocyanate-modified epoxy resins (such as “AER4152” manufactured by Asahi Kasei Epoxy Co., Ltd.), dicyclopentadiene skeleton type epoxy resins (for example, “Epiclon HP-7200L” manufactured by DIC Corporation), and positional isomers thereof. Have substituents such as alkyl groups and halogens. Substitutions, etc.

  Specific examples of the glycidylamine type epoxy resin include tetraglycidyldiaminodiphenylmethane (for example, “Sumiepoxy ELM434” manufactured by Sumitomo Chemical Co., Ltd., “Araldite MY720”, “Araldite MY721”, “Araldite” manufactured by Huntsman Advanced Materials, Inc. MY9512 ”,“ Araldite MY9612 ”,“ Araldite MY9634 ”,“ Araldite MY9663 ”,“ jER604 ”manufactured by Mitsubishi Chemical Corporation, etc.), diglycidylaniline (for example,“ GAN, GOT manufactured by Nippon Kayaku Co., Ltd. ”) And tetraglycidylxylenediamine (for example, “TETRAD-X” manufactured by Mitsubishi Gas Chemical Co., Ltd.).

  Specific examples of the glycidyl ester type epoxy resin include phthalic acid diglycidyl ester (for example, “Epomic R508” manufactured by Mitsui Chemicals, “Denacol EX-721” manufactured by Nagase ChemteX Corporation), and the like. ) Tetrahydrophthalic acid diglycidyl ester, (methyl) hexahydrophthalic acid diglycidyl ester (for example, “Epomic R540” manufactured by Mitsui Chemicals, Inc., “AK-601” manufactured by Nippon Kayaku Co., Ltd., etc.) , Isophthalic acid diglycidyl ester, dimer acid diglycidyl ester (for example, “jER871” manufactured by Mitsubishi Chemical Corporation, “Epototo YD-171” manufactured by Nippon Steel Chemical Co., Ltd., etc.), and various isomers thereof. There is a body.

  Typical examples of the alicyclic epoxy type epoxy resins include compounds having a cyclohexene oxide group, a tricyclodecene oxide group, a cyclopentene oxide group, and the like. Specifically, a vinylcyclohexene diepoxide, a vinylcyclohexene monoepoxide, ( 3 ′, 4′-epoxycyclohexane) methyl 3,4-epoxycyclohexanecarboxylate (for example, “Celoxide 2021P” manufactured by Daicel Corporation, “CY179” manufactured by Huntsman Advanced Materials Corporation), and the like. (3 ′, 4′-epoxycyclohexane) octyl 3,4-epoxycyclohexanecarboxylate (for example, “Celoxide 2081” manufactured by Daicel Corporation), 1-methyl-4- (2-methyloxirani) ) -7-oxabicyclo [4.1.0] heptane (for example, “Celoxide 3000” manufactured by Daicel Corporation), 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4) -Epoxy) cyclohexane-m-dioxane, bis (3,4-epoxycyclohexylmethylene) adipate, bis (3,4-epoxycyclohexylmethylene) adipate, bis (2-methyl-4,5-epoxycyclohexylmethylene) acipate, etc. .

  Specific examples of epoxy resins having epoxy groups of both glycidyl ether type and glycidyl amine type include triglycidylaminophenol and triglycidylaminocresol (for example, “Sumiepoxy ELM-100” and “Sumiepoxy” manufactured by Sumitomo Chemical Co., Ltd.). "ELM-120", Mitsubishi Chemical Corporation "jER630", Huntsman Advanced Materials Corporation "Araldite MY0500", "Araldite MY0510", "Araldite MY0600", "Araldite MY0610", Nippon Steel Chemical Co., Ltd. "Epototo YDCN-701" manufactured by the company, etc.).

  These epoxy resins may be used individually by 1 type, and may use 2 or more types together.

<Radically polymerizable unsaturated compound>
A radical polymerizable unsaturated compound may be added to the matrix resin composition used for the prepreg of the present invention. The radically polymerizable unsaturated compound is a low molecular weight compound, a high molecular compound or an oligomer having a radically polymerizable unsaturated bond, that is, a radically polymerizable double bond or triple bond in the molecule.

  Examples of the low molecular weight compound having a radical polymerizable unsaturated bond in the molecule include a low molecular weight compound having one or more, for example, 1 to 6 radical polymerizable unsaturated bonds in the molecule. For example, (meth) acrylate compounds, allyl phthalate compounds, allyl isophthalate compounds, allyl terephthalate compounds, allyl cyanurate compounds, and the like. An acrylate compound and a methacrylate compound are preferable.

  Examples of the low molecular weight compound having one radical polymerizable unsaturated bond in the molecule include phenoxyethyl acrylate (for example, “Biscoat # 192” manufactured by Osaka Organic Chemical Industry Co., Ltd.) and ethoxydiethylene glycol acrylate (for example, manufactured by Kyoeisha Chemical Co., Ltd.). "Light acrylate EC-A"), methoxytriethylene glycol acrylate (for example, "Light acrylate MTG-A" manufactured by Kyoeisha Chemical Co., Ltd.), methoxydipropylene glycol acrylate (for example, "Light acrylate DPM-A manufactured by Kyoeisha Chemical Co., Ltd.) )), Isobornyl acrylate (for example, “Light acrylate IB-XA” manufactured by Kyoeisha Chemical Co., Ltd.), phenylglycidyl ether acrylic acid adduct (for example, “Denacol Acrylic manufactured by Nagase ChemteX Corporation) Over door DA-141 "), and the like.

  Examples of low molecular weight compounds having two radically polymerizable unsaturated bonds in the molecule include triethylene glycol diacrylate (for example, “Light Ester 3EG-A” manufactured by Kyoeisha Chemical Co., Ltd.), tetraethylene glycol diacrylate (for example, Toa Gosei). “Aronix M-240” manufactured by Chemical Industry Co., Ltd.), neopentyl glycol diacrylate (for example, “Light Ester NP-A” manufactured by Kyoeisha Chemical Co., Ltd.), 1,6-hexanediol diacrylate (for example, Kyoeisha Chemical Co., Ltd.) "Light ester 1,6HX-A"), bisphenol A propylene oxide adduct diacrylate (for example, "light ester BP-2PA" manufactured by Kyoeisha Chemical Co., Ltd.), bisphenol A ethylene oxide adduct diacrylate (for example, Sanyo Chemical Industries) Stock Board "Neomer BA-641"), hydrogenated bisphenol A propylene oxide adduct diacrylate (for example, "Neomer HA-605" manufactured by Sanyo Chemical Industries, Ltd.), hydrogenated bisphenol A ethylene oxide adduct diacrylate (for example, Sanyo Kasei) "Neomer HA-601" manufactured by Kogyo Co., Ltd.), Bisphenol S ethylene oxide adduct diacrylate (for example, "Aronix M-205" manufactured by Toa Gosei Chemical Co., Ltd.), dimethylolpropane tricyclodecane diacrylate (for example, Kyoeisha Chemical Co., Ltd.) "Light Ester DCP-A" manufactured by Co., Ltd.), ethylene glycol dimethacrylate (for example, "Light Ester EG" manufactured by Kyoeisha Chemical Co., Ltd.), diethylene glycol dimethacrylate (for example, "Light Ester manufactured by Kyoeisha Chemical Co., Ltd.) Steal 2EG "), triethylene glycol dimethacrylate (for example," Neomer PM-201 "manufactured by Sanyo Chemical Industries, Ltd.), 1,4-butanediol dimethacrylate (for example," Light Ester 1.4BG "manufactured by Kyoeisha Chemical Co., Ltd.) ), 1,6-hexanediol dimethacrylate (for example, “Light Ester 1 / 6HX” manufactured by Kyoeisha Chemical Co., Ltd.), glycerin dimethacrylate (for example, “Light Ester G-101P” manufactured by Kyoeisha Chemical Co., Ltd.), bisphenol A ethylene oxide Adduct dimethacrylate (for example, “light ester BP-2EM” manufactured by Kyoeisha Chemical Co., Ltd.), bisphenol A propylene oxide adduct dimethacrylate, bis (2-acryloyloxyethyl) (2-hydroxyethyl) cyanurate (for example, East "Aronix M-215" manufactured by Asahi Chemical Industry Co., Ltd.), bisphenol A diglycidyl ether acrylic acid adduct (for example, "epoxy ester 3000A" manufactured by Kyoeisha Chemical Co., Ltd.), bisphenol A ethylene oxide adduct diglycidyl ether acrylic acid Adduct, bisphenol A ethylene oxide adduct diglycidyl ether methacrylic acid adduct, bisphenol A propylene oxide adduct diglycidyl ether acrylic acid adduct (for example, “Epoxy ester 3002A” manufactured by Kyoeisha Chemical Co., Ltd.), bisphenol A propylene oxide adduct Diglycidyl ether methacrylic acid adduct (eg “Epoxy ester 3002M” manufactured by Kyoeisha Chemical Co., Ltd.), glycerol diglycidyl ether acrylic acid adduct (eg "Epoxy Ester 80MFA" manufactured by Seikagaku Co., Ltd.), diglycidyl phthalate acrylic acid adduct (eg, "Denacol Acrylate DA-721" manufactured by Nagase ChemteX Corporation), diglycidyl tetrahydrophthalate acrylic acid adduct (eg, Nagase) “Denacol Acrylate DA-722” manufactured by Chemtex Co., Ltd.), resorcinol diglycidyl ether methacrylic acid adduct (eg “Denacol Acrylate DA-201” manufactured by Nagase Chemtex Corp.), diallyl phthalate, diallyl isophthalate, Examples include diallyl terephthalate.

  Examples of low molecular weight compounds having three radically polymerizable unsaturated bonds in the molecule include trimethylolpropane triacrylate (for example, “Aronix M-309” manufactured by Toa Gosei Chemical Co., Ltd.), pentaerythritol triacrylate (for example, Toa Gosei). "Aronix M-305" manufactured by Chemical Industry Co., Ltd.), trimethylolpropane trimethacrylate (for example, "Light Ester TMP" manufactured by Kyoeisha Chemical Co., Ltd.), tris (2-acryloyloxyethyl) cyanurate (for example, Toa Gosei Chemical Co., Ltd.) "Aronix M-315" manufactured by company), tris (2-acryloyloxyethyl) phosphate (for example, "Biscoat 3PA" manufactured by Osaka Organic Chemical Industry Co., Ltd.), glycerol triglycidyl ether acrylic acid adduct (for example, Nagase Chem) Box of Ltd. "Denacol acrylate DA-314"), such as triallyl cyanurate.

  Examples of low molecular weight compounds having four radical polymerizable unsaturated bonds in the molecule include pentaerythritol tetraacrylate (for example, “Light Ester BP-4A” manufactured by Kyoeisha Chemical Co., Ltd.), glycerin dimethacrylate isophorone diisocyanate adduct (for example, Kyoeisha). “Urethane acrylate UA-101I” manufactured by Chemical Co., Ltd.), glycerin dimethacrylate hexamethylene diisocyanate adduct (eg, “urethane acrylate UA-101H” manufactured by Kyoeisha Chemical Co., Ltd.), glycerin dimethacrylate tolylene diisocyanate adduct (eg, Kyoeisha) “Urethane acrylate UA-101T” manufactured by Chemical Co., Ltd.) and the like.

  Examples of the low molecular weight compound having five radical polymerizable unsaturated bonds in the molecule include dipentaerythritol pentaacrylate (for example, “Neomer DA-600” manufactured by Sanyo Chemical Industries, Ltd.).

  Examples of low molecular weight compounds having six radically polymerizable unsaturated bonds in the molecule include dipentaerythritol hexaacrylate (for example, “Light Ester DPE-6A” manufactured by Kyoeisha Chemical Co., Ltd.), pentaerythritol trimethacrylate isophorone diisocyanate adduct ( For example, “Urethane acrylate UA-306I” manufactured by Kyoeisha Chemical Co., Ltd.), pentaerythritol trimethacrylate hexamethylene diisocyanate adduct (for example, “Urethane acrylate UA-306H” manufactured by Kyoeisha Chemical Co., Ltd.), pentaerythritol trimethacrylate tolylene diisocyanate addition (For example, “urethane acrylate UA-306T” manufactured by Kyoeisha Chemical Co., Ltd.).

As the radically polymerizable unsaturated compound of the present invention, a polymer compound or oligomer having a radically polymerizable unsaturated bond at the terminal, side chain, or main chain can be used. As a compound having a radically polymerizable unsaturated compound at the terminal, for example, a compound in which the terminal hydroxyl group of polyethylene glycol or polypropylene glycol is esterified with acrylic acid or methacrylic acid, polyester containing maleic acid or fumaric acid as an acid component, radical polymerization And polyimide having an amino terminus sealed with maleic anhydride, nadic anhydride, ethynyl phthalic anhydride, or the like having an ionic unsaturated bond.
Examples of unsaturated polyester resins having a radically polymerizable unsaturated compound in the main chain include orthophthalic acid resins, isophthalic acid resins, terephthalic acid resins, bisphenol resins, propylene glycol-maleic acid resins, dicyclopentadiene. Or those obtained by introducing a derivative thereof into an unsaturated polyester composition.

As the radical polymerizable unsaturated compound of the present invention, a low molecular compound, a high molecular compound or an oligomer having a partial structure which reacts with an epoxy resin together with a radical polymerizable unsaturated bond can also be used. When such a compound is used, a chemical bond is formed between the polymer block constituted by the epoxy resin and the polymer block of the radical polymerizable unsaturated compound in the cured product, and the morphology and physical properties can be improved.
Examples of the partial structure that reacts with the epoxy resin include an epoxy group, a carboxyl group, a hydroxyl group, an alkoxymethyl group, a primary or secondary amine, an amide, a 1,2-dicarboxylic anhydride structure, and a nitrogen-containing heterocyclic ring.

Examples of such compounds include 2-acryloyloxyethyl hydrogen phthalate (for example, “Biscoat # 2000” manufactured by Osaka Organic Chemical Industry Co., Ltd.), 2-acryloyloxypropyl hydrogen phthalate, which has one radical polymerizable unsaturated bond. (For example, “Biscoat # 2100” manufactured by Osaka Organic Chemical Industries, Ltd.), 2-methacryloyloxyethyl hydrogen phthalate (for example, “Light Ester HO-MP” manufactured by Kyoeisha Chemical Co., Ltd.), 4-hydroxybutyl acrylate, 2-acryloyl Examples thereof include oxyethyl 2-hydroxypropyl phthalate (for example, “Biscoat # 2311HP” manufactured by Osaka Organic Chemical Industries, Ltd.), maleic anhydride, nadic anhydride and the like.
Moreover, as what has two radically polymerizable unsaturated bonds, bisphenol A diglycidyl ether acrylic acid partial adduct (for example, "Lipoxy SP-1509H1" manufactured by Showa Denko KK), bis (2-acryloyloxyethyl) 2 -Hydroxyethyl cyanurate (for example, "Aronix M-215" manufactured by Toa Gosei Chemical Co., Ltd.) and the like.

The radically polymerizable unsaturated compound of the present invention is more preferably a compound having a hydroxyl group, a carboxyl group, an amino group or the like. This is because the epoxy group reacts with them, or is compatible with the interaction with the hydroxyl group, carboxyl group, etc. generated by the reaction of the epoxy group.
In the case where a high molecular weight component generated by radical polymerization on the prepreg surface, which will be described later, has a crosslinked structure and a large viscosity increasing effect is obtained on the prepreg surface, when one kind of radically polymerizable unsaturated compound is used alone, It is preferable to use a compound having a plurality of radically polymerizable unsaturated bonds in the molecule.

As the radical polymerizable unsaturated compound used in the present invention, one kind of compound may be used alone, or two or more kinds of compounds may be used.

<Curing agent for epoxy resin>
Examples of the epoxy resin curing agent contained in the matrix resin composition contained in the prepreg of the present invention include amines, acid anhydrides (such as carboxylic acid anhydrides), phenols (such as novolak resins), mercaptans, Lewis acid amine complexes, and oniums. Examples of the structure include salts and imidazoles, but any structure can be used as long as the epoxy resin can be cured. Among these, amine type curing agents are preferable. These curing agents may be used alone or in combination of two or more.

  Examples of amine-type curing agents include aromatic amines such as diaminodiphenylmethane and diaminodiphenylsulfone, aliphatic amines, imidazole derivatives, dicyandiamide, tetramethylguanidine, thiourea-added amines, and isomers and modified forms thereof. . Among these, dicyandiamide is particularly preferable in terms of excellent prepreg storage.

Moreover, in order to raise the hardening activity of the hardening | curing agent of an epoxy resin, you may use a hardening adjuvant for the matrix resin composition contained in the prepreg of this invention. For example, when the epoxy resin curing agent is dicyandiamide, the curing aid is 3-phenyl-1,1-dimethylurea, 3- (3,4-dichlorophenyl) -1,1-dimethylurea (DCMU), 3- ( Urea derivatives such as 3-chloro-4-methylphenyl) -1,1-dimethylurea and 2,4-bis (3,3-dimethylureido) toluene are preferred, and the epoxy resin curing agent is carboxylic anhydride or novolak. When it is a resin, the curing aid is preferably a tertiary amine, and when the epoxy resin curing agent is diaminodiphenyl sulfone, the curing aid is an imidazole compound, a urea compound such as phenyldimethylurea (PDMU), or boron trifluoride. Amine complexes such as monoethylamine and boron trichloride amine complexes are preferred.
Among these, a combination in which the curing agent is dicyandiamide and the curing aid is DCMU is particularly preferable.

<Polymerization initiator generating radicals>
In the prepreg of the present invention, a polymerization initiator that generates radicals can be used. When stimulating radical generation by UV or visible light irradiation, use a photoinitiator that undergoes reactions such as cleavage, hydrogen abstraction, and electron transfer when irradiated with UV or visible light. Can do. In addition, when stimulation for generating radicals is performed by irradiation with infrared rays or ultrasonic waves, or by pressing a heating plate, a thermal polymerization initiator that generates radicals by heating can be used.

  Examples of the photopolymerization initiator include benzophenone, ω-bromoacetophenone, chloroacetone, acetophenone, diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, p-dimethylaminoacetophenone, p-dimethylaminopropiophenone, 2-chlorobenzophenone, p, p'-dichlorobenzophenone, 4,4-bis (diethylamino) benzophenone, 2,4,6-trimethylbenzophenone, 4-phenylbenzophenone, Michler's ketone, benzoin methyl ether, benzoin isobutyl ether, benzoin-n -Butyl ether, benzyl methyl ketal, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy 2-methyl-1-phenyl-propan-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy- 1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one, 2-methyl-1- (4-methylthiophenyl) -2- Morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2- (dimethylamino) -2-[(4-methylphenyl) methyl]- Examples thereof include, but are not limited to, carbonyl-based photopolymerization initiators such as 1- [4- (4-morpholinyl) phenyl] -1-butanone. Furthermore, sulfide photopolymerization initiators such as diphenyl disulfide, dibenzyl disulfide and tetraethylmethylammonium sulfide, quinone photopolymerization initiators such as benzoquinone, t-butylanthraquinone and 2-ethylanthraquinone, adibisisobutyronitrile, 2 Azo photopolymerization initiators such as 2'-azobispropane and hydrazine, thioxanthone photopolymerization initiators such as thioxanthone, 2-chlorothioxanthone and 2-methylthioxanthone, benzoyl peroxide, di-t-butyl peroxide, etc. Peroxide-based photopolymerization initiator, 1- [4- (phenylthio) phenyl] -1,2-octanedione-2- (O-benzoyloxime), O-acetyl-1- [6- (2-methylbenzoyl) ) -9-ethyl-9H-carbazole-3 -Il] ethanone oxime and other oxime ester compound photopolymerization initiators, oxyphenylacetic acid, oxyphenylacetic acid ester photopolymerization such as 2- [2-oxo-2-phenylacetoxyethoxy] ethyl ester and oxyphenylacetic acid Agents and the like. These photopolymerization initiators can be used alone or in combination of two or more.

  As a thermal polymerization initiator that generates radicals by heating, for example, an azo compound, an organic peroxide, or the like can be used. Examples of the azo compound include 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) (for example, “V-70” manufactured by Wako Pure Chemical Industries, Ltd.), and 2,2′-. Azobis (2,4-dimethylvaleronitrile (for example, “V-65” manufactured by Wako Pure Chemical Industries, Ltd.), 2,2′-azobisisobutyronitrile (for example, Wako Pure Chemical Industries, Ltd.) "V-60", manufactured by Wako Pure Chemical Industries, Ltd.), 2,2'-azobis (2-methylbutyronitrile (for example, "V-59" manufactured by Wako Pure Chemical Industries, Ltd.), 1 , 1′-azobis (cyclohexane-1-carbonitrile) (for example, “V-40” manufactured by Wako Pure Chemical Industries, Ltd.), 1-[(1-cyano-1-methylethyl) azo] Formamide (for example, sum "V-30" manufactured by Junyaku Kogyo Co., Ltd.), 2-phenylazo-4-methoxy-2,4-dimethyl-valeronitrile (for example, "V-19" manufactured by Wako Pure Chemical Industries, Ltd.) Azonitrile compounds such as 2,2′-azobis [2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide] (for example, Wako Pure Chemical Industries Ltd.) “VA-080” manufactured by the company, etc.), 2,2′-azobis [2-methyl-N- [1,1-bis (hydroxymethyl) ethyl] propionamide] (for example, Wako Pure Chemical Industries, Ltd.) "VA-082" manufactured by the company, etc.), 2,2'-azobis [2-methyl-N- [2- (1-hydroxybutyl)]-propionamide] (for example, Wako Pure Chemical Industries, Ltd.) "VA-085" manufactured by the company, etc.), 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) -propionamide] (for example, "VA manufactured by Wako Pure Chemical Industries, Ltd." -086 "), 2,2'-azobis (2-methylpropionamide) dihydrate (for example," VA-088 "manufactured by Wako Pure Chemical Industries, Ltd.), 2,2 ' -Azobis [N- (2-propenyl) -2-methylpropionamide] (for example, “VF-096” manufactured by Wako Pure Chemical Industries, Ltd.), 2,2′-azobis (N-butyl- 2-methylpropionamide) (for example, “VAm-110” manufactured by Wako Pure Chemical Industries, Ltd.), 2,2′-azobis (N-cyclohexyl-2-methylpropionami) (For example, “VAm-111” manufactured by Wako Pure Chemical Industries, Ltd.). ), 2,2′-azobis (2,4,4-trimethylpentane) (for example, “VR-110” manufactured by Wako Pure Chemical Industries, Ltd.), and 2,2′-azobis. And alkylazo compounds such as (2-methylpropane) (for example, “VR-160” manufactured by Wako Pure Chemical Industries, Ltd.). Examples of the organic peroxide include 1,1-bis (t-butylperoxy) -2,2,5-trimethylcyclohexane (for example, “Perhexa 3M-95” manufactured by NOF Corporation), 1,1-bis. (T-butylperoxy) cyclododecane (for example, “Perhexa CD” manufactured by NOF Corporation, 1,1,3,3-tetramethylhydroperoxide (for example, “Perocta H” manufactured by NOF Corporation), 1,1 -Dimethylbutyl peroxide (for example, “Perhexyl H” manufactured by NOF Corporation), bis (1-tert-butylperoxy-1-methylethyl) benzene (for example, “Perbutyl P” manufactured by NOF Corporation), dicumyl peroxide (For example, “Park Mill D” manufactured by NOF Corporation), 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane (for example, NOF Corporation) "Perhexa 25B"), t-butylcumyl peroxide (for example, "Perbutyl C" manufactured by NOF Corporation), di-t-butyl peroxide (for example, "Perbutyl D" manufactured by NOF Corporation), 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne (for example, “Perhexin 25B” manufactured by NOF Corporation), benzoyl peroxide, lauroyl peroxide (for example, “PAROIL L manufactured by NOF Corporation) ), Decanoyl peroxide (for example, “Sanperox-DPO” manufactured by Sanken Chemical Co., Ltd.), dicyclohexyl peroxydicarbonate (for example, “Sanperox-CD” manufactured by Sanken Chemical Co., Ltd.), bis (4-t -Butylcyclohexyl) peroxydicarbonate (for example, “Parroyl TCP” manufactured by NOF Corporation) t-butyl 2-ethylperhexanoate (for example, “Perbutyl O” manufactured by NOF Corporation), (1,1-dimethylpropyl) 2-ethylperhexanoate (for example, “TRIGONOX manufactured by Kayaku Akzo Corporation) 121 "), (1,1-dimethylbutyl) 2-ethylperhexanoate (for example," Kaya ester HO "manufactured by Kayaku Akzo Corporation), t-butyl 3,5,5-trimethylperhexanoate ( For example, “Perbutyl 355” manufactured by NOF Corporation, t-hexyl peroxyisopropyl monocarbonate (eg “Perhexyl I” manufactured by NOF Corporation), t-butyloxyisopropyl carbonate (eg “ Perbutyl I "), t-butyl peroxy-2-ethylhexyl carbonate (for example," Perb "manufactured by NOF Corporation) Chill E "), t-butyl peroxymaleic acid (for example," Perbutyl MA "manufactured by NOF Corporation), t-butyl peroxylaurate (for example," Perbutyl L "manufactured by NOF Corporation), t- Butyl peroxybenzoate (for example, “Perbutyl Z” manufactured by NOF Corporation) can be used. These thermal polymerization initiators may be used alone or in combination.

Further, as a means for generating radicals, a photopolymerization initiator and a thermal polymerization initiator may be used in combination.

<Additional ingredients>
The matrix resin composition contained in the prepreg of the present invention is one or more additional components selected from the group consisting of a thermoplastic resin, a thermoplastic elastomer and an elastomer as long as the effects of the present invention are not impaired. It may contain. These additional components have a role of optimizing the viscosity, storage elastic modulus and thixotropy of the matrix resin composition, and change the viscoelasticity of the cured product of the matrix resin composition, improve toughness, etc. There is a role. These additional components may be mixed together with various components, or may be previously dissolved in an epoxy resin.

  The thermoplastic resin that can be used in the present invention includes carbon-carbon bond, amide bond, imide bond, ester bond, ether bond, carbonate bond, urethane bond, urea bond, thioether bond, sulfone bond, imidazole bond and carbonyl bond. A thermoplastic resin having a bond selected from the group consisting of in the main chain is preferred. Examples of such a thermoplastic resin include polyacrylate, polyamide, polyaramid, polyester, polycarbonate, polyphenylene sulfide, polybenzimidazole, polyimide, polyetherimide, polysulfone, and polyethersulfone. Among these, polyimide, polyetherimide, polysulfone, and polyethersulfone are particularly preferable because of excellent heat resistance.

  When using a thermoplastic resin for this invention, it is preferable from a viewpoint of the toughness improvement of a cured resin, and environmental resistance maintenance that a thermoplastic resin has a reactive functional group with an epoxy resin. Particularly preferred functional groups are a carboxyl group, an amino group and a hydroxyl group.

  The matrix resin composition contained in the prepreg of the present invention may contain a solid additive as an additional component if the matrix resin composition is liquid at the time of impregnating the matrix resin composition into the reinforcing fibers. Examples of solid additives that can be used in the present invention include inorganic particles such as silica, alumina, titanium oxide, zirconia, clay minerals, talc, mica, and ferrite, and carbonaceous components such as carbon nanotubes and fullerenes. Is mentioned. These solid additives have the effect of imparting thixotropy to the uncured matrix resin composition, the elastic modulus, heat resistance, fatigue strength, and / or wear resistance of the cured product of the matrix resin composition. There is an effect to improve. In addition, particles of metal, carbon black, copper oxide, tin oxide and the like can be included as solid additives for improving conductivity. The content of the solid additive is preferably 50% or less of the mass of the matrix resin composition.

(Prepreg)
The prepreg of the present invention preferably has a reinforcing fiber basis weight of 75 g / m ² or more. When it is less than 75 g / m ² , bumps due to auxiliary yarns and stitch yarns are generated, which is not preferable. In addition, since the number of times of lamination increases at the time of molding by prepreg lamination, it is not particularly suitable for industrial use. More preferably if the basis weight of the reinforcing fibers of 125 g / ^{m 2} or more, particularly preferably in the case of 250 g / ^{m 2} or more.

In the prepreg of the present invention, the basis weight of the reinforcing fiber is preferably 2000 g / m ² or less. When it exceeds 2000 g / m ² , the impregnation of the matrix resin is deteriorated, and the prepreg drapability is lowered and it is difficult to handle.

The viscosity of the matrix resin composition is preferably 10 Pa · s or higher at 30 ° C. When the viscosity is less than 10 Pa · s, the handleability, particularly the tackiness of the prepreg is deteriorated, and the work tends to be difficult. The viscosity is more preferably 30 Pa · s or more, and further preferably 50 Pa · s or more. On the other hand, when the viscosity exceeds 1,000,000 Pa · s, it is difficult to impregnate the reinforcing fiber base or the reinforcing fiber stitch base, which is not preferable. Further, the prepreg drapability is too low, and the handleability is also deteriorated. The case of 500,000 Pa · s or less is preferable because the drape property is further improved.

  Hereinafter, the prepreg of the present invention will be described more specifically with reference to examples, but the prepreg of the present invention is not limited to the examples. The reinforcing fibers, resin raw materials, and methods for measuring physical properties used in the examples are shown below.

<Reinforcing fiber>
・ Carbon fiber yarn 1
Average single fiber fineness: 1.35 dtex
Roundness: 0.76
Diameter Di: 11.9 μm
Number of filaments: 24,000 Strand strength: 4500 MPa
Strand elastic modulus: 242 GPa

・ Carbon fiber yarn 2
Average single fiber fineness: 0.53 dtex
Roundness: 0.85
Diameter Di: 7.0 μm
Number of filaments: 60,000 Strand strength: 4900 MPa
Strand elastic modulus: 250 GPa

<Auxiliary thread>
・ Auxiliary thread 1
Glass / low melting point nylon composite yarn Glass fiber: Nitto Boseki Co., Ltd., product name: D450
Nylon fiber: manufactured by Toray Industries, Inc., product name: Elder 110 dt
Compound yarn form: assortment

<Epoxy resin>
・ Bisphenol A liquid epoxy resin (Mitsubishi Chemical Corporation, product name: jER-828)
・ Bisphenol A type solid epoxy resin (Mitsubishi Chemical Corporation, product name: jER-1002)
-Epoxy resin containing oxazolidone ring (product name: AER4152 manufactured by Asahi Kasei E-materials)

<Curing agent>
Dicyandiamide (Mitsubishi Chemical Corporation, product name: jER Cure DICY15).

<Curing aid>
An aromatic compound having a urea group (manufactured by Hodogaya Chemical Co., Ltd., product name: DCMU99).

<Thermoplastic resin>
・ Polyvinyl formal (manufactured by JNC, product name: Vinylec E)

<Method for measuring resin viscosity>
The viscosity is measured by the following method. That is, with AR-G2 manufactured by TA Instruments or an equivalent device, a flat plate with a measurement frequency of 10 rad / s, a diameter of 25 mm, a gap between the plates of 0.5 mm, and a temperature increase rate of 2 ° C./min. Measure in the temperature range up to ~ 34 ° C and determine the viscosity at 30 ° C. If the measured value at just 30 ° C cannot be obtained, it is determined by complementing from the nearest two points.

<Method for measuring diameter and roundness of carbon fiber bundle>
(1) Preparation of sample A carbon fiber bundle cut to a length of 5 cm is embedded in an epoxy resin (Epomount main agent: Epomount curing agent = 100: 9 (mass ratio)), cut to 2 cm, and the cross section is exposed. And mirror polished.

(2) Etching treatment of observation surface Further, in order to clarify the outer shape of the fiber, the cross section of the sample was etched by the following method.
-Equipment used: JEOL Ltd. JP-170 plasma etching equipment-Processing conditions: Atmospheric gas: Ar / 02 = 75/25
・ Plasma output: 50W
・ Vacuum degree: About 120Pa
・ Processing time: 5 minutes

(3) SEM observation The cross section of the sample obtained by said (1) and (2) was observed using SEM (PHILIPS FEI-XL20), and the photograph in which five or more fiber cross sections are reflected on the screen 5 images were taken arbitrarily.

(4) Measurement of single fiber diameter of carbon fiber bundle For each sample, arbitrarily select 20 cross-sections from 5 SEM photographs, but select 3 or more single-fiber sections from 1 photograph, and use image analysis software (Nippon Roper) The outer shape of the fiber cross section was traced using a product name, “Image-Pro PLUS” manufactured by Co., Ltd., and the major axis d (maximum ferret diameter) of the cross section was measured. The average of the major axis d of all selected single fiber cross sections was defined as the diameter Di of the single fiber of the carbon fiber bundle.

(5) The roundness measurement image analysis software (manufactured by Nippon Roper Co., Ltd., product name: Image-Pro PLUS) is used to trace the outer shape of the fiber cross section, and the circumference L and area. S was measured. For each sample, 20 fibers were arbitrarily selected from 5 SEM photographs, but 3 or more fiber cross sections were selected from 1 photograph, and the average values of L and S were obtained, and the roundness was calculated by the following equation. .
Roundness = (4πS) / L ²

<Evaluation of prepreg impregnation>
The prepared prepreg was visually observed, and the impregnation property of the resin composition was evaluated in the following two stages.
○: No unimpregnated portion was observed.
X: An unimpregnated part was observed.

<Evaluation of prepreg tack>
The tackiness of the prepreg was evaluated according to the following four levels from the touch feeling of the prepared prepreg by hand and the replaceability between the prepregs.
A: With a moderate tack, the replacement can be performed smoothly.
○: Feels somewhat sticky, but can be replaced.
X (weak): Almost no tack.
X (Strong): Tack is very strong, resin adheres to the hand, or replacement with the prepreg shape maintained is impossible.

<Evaluation of prepreg drape property>
The prepared prepreg was bent with a finger, and the draping property of the prepreg was evaluated in two stages as shown below.
A: Very soft and quickly follows a curved mold.
×: Rigid and hard, difficult to follow a curved mold.

[Production of fiber-reinforced composite materials]
<Autoclave curing>
A predetermined number of prepregs are stacked and bagged, and after the bag is depressurized with a vacuum pump, the bag is placed in an autoclave, and the temperature inside the autoclave is increased at a rate of temperature rise of 2 ° C./min and held at 80 ° C. for 1 hour. Subsequently, the temperature was raised at a rate of temperature rise of 2 ° C./min, and the mixture was kept at 130 ° C. for 1.5 hours and cured to obtain a fiber-reinforced composite material. At that time, the pressure inside the autoclave was maintained at 80 ° C. for 1 hour and then increased to 0.6 MPa. Further, the suction by the vacuum pump was stopped when the pressure in the autoclave was 0.14 MPa, and the inside of the bag was opened to the atmosphere.

<Vacuum bag curing>
A predetermined number of prepregs are stacked and bagged, and after the inside of the bag is depressurized by a vacuum pump, this is put into an oven, the inside of the oven is heated at a temperature rising rate of 0.5 ° C./min, and kept at 90 ° C. for 2 hours. did. Next, the temperature was raised at a rate of temperature rise of 0.17 ° C./min, and kept at 110 ° C. for 4 hours for curing to obtain a fiber-reinforced composite material.

[Evaluation of fiber reinforced composite materials]
<Evaluation of 0 ° compression characteristics>
When evaluating the compression characteristics in the 0 ° direction when the direction in which the fibers of the fiber reinforced composite material in which the fiber directions are aligned is set to 0 °, the evaluation was performed as follows.
Six test pieces each having a width of 12.7 mm, a length of 80 mm, and a thickness of 1 mm were prepared from a fiber-reinforced composite material obtained by autoclave curing or vacuum bag curing with a two-ply laminate of prepregs. The length direction of the test piece is the 0 ° direction of the fiber. About the obtained test piece, in accordance with SACMA SRM 1R, using an INSTRON 5882 measuring machine equipped with a 100 kN load cell, in an environment of a temperature of 23 ° C. and a humidity of 50% RH, at a crosshead speed of 1.27 mm / min, The compressive strength and compressive elastic modulus were measured, and the measured value was converted to Vf (fiber volume content) 56%. Six test pieces were measured in the same manner, and an average value was obtained. The measurement was performed by adhering a tab cut out from the same plate to each test piece.

<Evaluation of 0 ° bending characteristics>
When evaluating the bending property in the 0 ° direction when the direction in which the fibers of the fiber reinforced composite material in which the fiber directions are aligned is defined as 0 °, the evaluation was performed as follows. Six test pieces having a length of 120 mm, a width of 12.7 mm, and a thickness of 2 mm were produced from a fiber-reinforced composite material obtained by autoclave curing or vacuum bag curing using a four-ply laminate of prepregs. The length direction of the test piece is the 0 ° direction of the fiber. The obtained test piece was compliant with ASTM D790, using an INSTRON 4465 measuring machine equipped with a 5 kN load cell, in an environment of a temperature of 23 ° C. and a humidity of 50% RH, an indenter diameter of 5.0 mm, a support diameter of 3.2 mm, L Bending strength, bending elastic modulus, and bending breaking strain were measured under the condition of / D = 40. In addition, about bending strength and a bending elastic modulus, the measured value was converted into Vf56%. Six test pieces were measured in the same manner, and an average value was obtained.

<Evaluation of 90 ° bending characteristics>
When evaluating the bending characteristics in the 90 ° direction when the direction in which the fibers of the fiber reinforced composite material in which the fiber directions are aligned is 0 °, the evaluation was performed as follows. Six prepregs having a width of 25.4 mm, a length of 60 mm, and a thickness of 2 mm were prepared from a fiber-reinforced composite material obtained by autoclave curing or vacuum bag curing, with the prepreg being aligned in a four-ply manner. The length direction of the test piece is the 90 ° direction of the fiber.
The obtained test piece was compliant with ASTM D790, using an INSTRON 4465 measuring machine equipped with a 500 N load cell, in an environment of temperature 23 ° C. and humidity 50% RH, indenter diameter = 5.0 mm, support diameter = 3.2 mm. Under the conditions of L / D = 16, bending strength, bending elastic modulus, and bending breaking strain were measured. Six test pieces were measured in the same manner, and an average value was obtained.

<Evaluation of ILSS characteristics>
Six test pieces having a width of 6.3 mm, a length of 20 mm, and a thickness of 2.6 mm were prepared from a fiber-reinforced composite material obtained by stacking prepregs into a four-ply laminate and autoclave curing or vacuum bag curing. The direction in which the fibers of the fiber-reinforced composite material in which the fiber directions are aligned is the 0 ° direction of the fibers, and the length direction of the test piece is the 0 ° direction of the fibers.
About the obtained test piece, in accordance with ASTM D 2344, using an INSTRON 4465 measuring machine equipped with a 5 kN load cell, in an environment of a temperature of 23 ° C. and a humidity of 50% RH, a crosshead speed of 1.27 mm / min, an indenter diameter of 3 The ILSS strength (interlaminar shear strength) was measured under the conditions of 0.2 mm, support diameter 1.6 mm, and L / D = 4.

<Evaluation of G′-Tg>
One prepreg having a width of 12.7 mm, a length of 55 mm, and a thickness of 2 mm was produced from a fiber-reinforced composite material obtained by stacking prepregs into four plies and curing by autoclave or vacuum bag curing. The direction in which the fibers of the fiber-reinforced composite material in which the fiber directions are aligned is the 0 ° direction of the fibers, and the length direction of the test piece is the 0 ° direction of the fibers.
About the obtained test piece, based on ASTM D4065, using a measuring machine ARES-RDA (manufactured by TA Instruments), a temperature rising rate of 5 ° C./min, a frequency of 1 Hz, a strain of 0.05%, and a measuring temperature range G′-Tg was measured under conditions of room temperature to 180 ° C.

(Example 1)
The following resin composition 1 was used as a matrix resin. That is, 72 parts by weight of jER828, 10 parts by weight of jER1002, 30 parts by weight of AER4152, and 3 parts by weight of Vinylec E are dissolved in a uniformly mixed resin, 6 parts by weight of DICY15 and 4 parts by weight of DCMU99 are uniformly dispersed. The matrix resin was used as the matrix resin. The viscosity of this matrix resin at 30 ° C. was 2000 Pa · s.
Using carbon fiber 1 as the reinforcing fiber, preparing a carbon fiber yarn group aligned in one direction so as to be 300 g / m ² , the yarn group in a direction perpendicular to the carbon fiber yarn The reinforced fiber fabric 1 was obtained by alternately arranging at 25 mm intervals on both sides of the sheet and heating the surface of the sheet composed of carbon fiber yarns and auxiliary yarns to 80 ° C. A prepreg 1 was obtained by impregnating the reinforcing fiber fabric 1 with the matrix resin of the resin composition 1. The prepreg 1 had good tackiness and drapeability and good impregnation.

(Comparative Example 1)
A prepreg 2 was prepared in the same manner as in Example 1 except that the carbon fiber yarn 2 was used as the reinforcing fiber. Although the prepreg 2 was good in tackiness and drapeability, unimpregnated parts were occasionally observed.

Claims (5)

A sheet in which a plurality of tow-like carbon fiber yarns made of carbon fibers having a single fiber fineness of 1.2 to 2.4 dtex are arranged in parallel with each other, and the carbon fiber on one or both sides of the sheet A prepreg formed by impregnating a thermosetting matrix resin composition into a reinforcing fiber base composed of auxiliary yarns arranged at an angle different from the yarn.   A plurality of sheets of tow-like carbon fiber yarns made of carbon fibers having a single fiber fineness of 1.2 to 2.4 dtex are arranged in parallel with each other, and the arrangement direction of each sheet is A prepreg obtained by impregnating a thermosetting matrix resin composition into a reinforcing fiber stitch base material laminated at different angles with respect to a reference direction and integrated with stitch yarns. The prepreg according to claim 1 or 2, wherein the reinforcing fiber is a carbon fiber having a cross-sectional shape perpendicular to the fiber axis of a single fiber and having a roundness of 0.7 or more and 0.9 or less. The prepreg according to any one of claims 1 to 3, wherein the reinforcing fiber is a carbon fiber having a cross-sectional shape perpendicular to the fiber axis of a single fiber and having a diameter Di of 8 µm or more and 20 µm or less.   The prepreg according to claim 1, wherein the matrix resin composition is an epoxy resin composition.