JP2007119603A - Prepreg - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a prepreg giving fiber-reinforced composite materials excellent in various mechanical properties including compressive strength after impact, using a cationically polymerizable resin curable with active energy rays without the need of any costly heating step by autoclave or the like. <P>SOLUTION: The prepreg essentially comprises (A) a carbon fiber, (B) a cationically polymerizable compound, (C) a Lewis acid's onium salt and (D) organic particles. In this prepreg, the constituent(C) is contained at 0.01-20 pt(s).wt. based on 100 pts.wt. of the constituent(B), and the content of the constituent(D) in the prepreg is 1-20 wt.%, wherein the constituent(D) is distributed in higher concentration on the prepreg surface than the inside. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a prepreg capable of imparting excellent mechanical properties such as post-impact compression strength to a fiber reinforced composite material obtained by cationically curing a prepreg, and the prepreg is particularly suitable for aircraft members, satellites, rockets, space It is suitably used for spacecraft members such as return vehicles and automobile members.

  Fiber reinforced composite materials consisting of glass fiber, carbon fiber, aramid fiber and other reinforced fibers, and resin cured products such as unsaturated polyester resin, vinyl ester resin, epoxy resin, phenol resin, cyanate resin and bismaleimide resin are lightweight. However, because of its excellent mechanical properties such as strength, rigidity and impact resistance, it is applied to many fields such as aircraft members, spacecraft members, artificial satellite members, automobile members, railway vehicle members, ship members and sports equipment members. I came. Of these fields, aircraft members and spacecraft members require particularly excellent mechanical properties and heat resistance, so carbon fibers are most often used as reinforcing fibers, and among thermosetting resins as matrix resins. A combination of an epoxy resin and a polyamine having excellent heat resistance, elastic modulus, and chemical resistance and low curing shrinkage is most often used. The main method of manufacturing these fiber-reinforced composite materials is heating and pressure molding using autoclaves, etc., but this increases the cost of molding, increases the size of molding equipment, limits the molding size of equipment, and makes it difficult to mold complex shapes. This causes a problem of strength, a decrease in strength due to residual thermal stress in the molded product, and generation of cracks (see, for example, Patent Document 1).

  Considering the above-described problems, in recent years, establishment of a method for forming a fiber-reinforced composite material that does not require a heating step has been regarded as important. A typical example is curing with an active energy ray such as an electron beam, ultraviolet rays or visible light.

  In order to cure the matrix resin impregnated with carbon fiber by irradiating active energy rays to the inside, a matrix resin is required which has a high curing start reaction with respect to the active energy rays and hardly causes a stop reaction. Become. In Patent Document 2, carbon fiber is impregnated with a composition containing a polymerization initiator composed of a polymerizable unsaturated compound, an organic boron compound and an acidic compound as such a matrix resin, and the carbon fiber reinforced composite material is irradiated with light. Molding is described. However, the matrix resin described here is a radically polymerizable resin composition using a polymerizable unsaturated compound and is 1) susceptible to polymerization inhibition by oxygen, 2) large volume shrinkage upon curing, 3 4) It has problems such as strong odor and skin irritation, 4) heat resistance and mechanical properties are not so high, and applicable applications are limited.

  As a means for solving these problems, there is a method using a composition using a cationically polymerizable matrix resin. Compared to radically polymerizable resin compositions, cationically polymerizable resin compositions are generally less susceptible to polymerization inhibition by oxygen and have low odor and low irritation due to low volatility of components. The polymerizable resin composition has a small volume shrinkage upon curing, and is excellent in heat resistance and mechanical properties.

  However, the cationic polymerizable matrix resin, unlike the amine curable matrix resin, forms a cured product by self-crosslinking of the resin itself, so that the resin has a high crosslinking density and low resin toughness, and the cured product is a polyether. Since it is a structure-based skeleton, it has few polar functional groups and low adhesion to carbon fibers. Therefore, a fiber reinforced composite material obtained by curing a prepreg using a cationic polymerizable resin as a matrix resin has a problem of low compressive strength after impact, and an improvement thereof has been desired.

As a method for improving the compressive strength after impact of a fiber reinforced composite material, fibers made by laminating and curing prepregs by making polyamide particles present in the prepreg and distributing them at a higher concentration on the surface than inside the prepreg. The compressive strength after impact of the reinforced composite material can be improved (see, for example, Patent Document 3). However, it has not been clarified so far what combination of a cationically polymerizable matrix resin and particles can simultaneously satisfy the improvement in compressive strength after impact of the fiber-reinforced composite material and high curability with respect to active energy rays.
JP 2004-050574 A JP-A-9-296016 Japanese Unexamined Patent Publication No. 63-162732

  In view of the current situation, the object of the present invention does not require a heating process using an expensive autoclave or the like, and uses a cationic polymerizable resin that can be cured with active energy rays, and is excellent in various mechanical properties including compressive strength after impact. Another object of the present invention is to provide a prepreg that gives a fiber-reinforced composite material.

  The prepreg of the present invention has the following configuration in order to solve the above problems. That is, the prepreg includes at least the following constituent elements (A), (B), (C), and (D), and the constituent element (C) is 0.01 by 100 parts by weight of the constituent element (B). A prepreg containing -20 parts by weight, the component (D) being present in the prepreg in an amount of 1 to 20% by weight, and being distributed at a higher concentration on the surface than in the prepreg.

(A) Carbon fiber (B) Cationic polymerizable compound (C) Onium salt of Lewis acid (D) Organic particles

  The present invention does not require a heating process using an expensive autoclave or the like, and uses a cationic polymerizable resin that can be cured with an active energy ray to produce a fiber-reinforced composite material having excellent mechanical properties such as compressive strength after impact. It is to provide a prepreg to give.

  The prepreg of the present invention includes the following components (A), components (B), components (C), and components (D).

(A) Carbon fiber (B) Cationic polymerizable compound (C) Lewis acid onium salt (D) Organic particles The carbon fiber which is the constituent element (A) of the present invention has high moisture and heat resistance, specific strength and specific elastic modulus. It is effective for expressing in a fiber reinforced composite material.

The form and arrangement of the carbon fibers are not particularly limited, and can be appropriately selected from long fibers aligned in one direction, tows, woven fabrics, nonwoven fabrics, mats, knits, braids, rovings, choppeds, etc., but they are lightweight and durable. In order to obtain a fiber reinforced composite material at a higher level, the carbon fibers are preferably in the form of continuous fibers such as long fibers, woven fabrics, tows and rovings that are aligned in one direction.
Moreover, a preform can be applied as a form of carbon fiber. Here, the preform usually means a laminate of woven fabrics made of carbon fibers of long fibers, or a structure obtained by stitching and integrating them with stitch yarns, or a fiber structure such as a three-dimensional fabric / braid. .
As for the thickness of the carbon fiber, the single fiber diameter is preferably in the range of 1 to 20 μm, more preferably in the range of 3 to 10 μm. When the thickness of the carbon fiber exceeds 20 μm, the tensile strength and the tensile modulus tend to decrease. On the other hand, when the thickness of the carbon fiber is less than 1 μm, the productivity of the carbon fiber is lowered and the cost is increased.
Any type of carbon fiber can be used for the carbon fiber depending on the application. From the standpoint of high impact resistance when used as the fiber's original tensile strength and fiber-reinforced composite material, the so-called high-strength carbon fiber is used. Is preferred. That is, a carbon fiber having a strand tensile strength in a strand tensile test of 4 GPa or more is preferable, and a carbon fiber of 4.6 GPa or more is more preferable. The higher the strand tensile strength, the better. However, about 6.0 GPa is often sufficient. When the strand tensile strength exceeds 7.0 GPa, the processability of the obtained fiber-reinforced composite material may be deteriorated.

  Further, the tensile elongation at break of the carbon fiber is preferably 1.7% or more, and more preferably 1.8% or more. The higher the tensile elongation at break, the better. However, if it is about 2.0%, it is often sufficient for the purpose of the present invention.

  The strand tensile test here refers to a test performed based on JIS R7601 (1986).

  The carbon fiber preferably has a tensile modulus of 200 GPa or more. Use of carbon fibers having a high tensile elastic modulus leads to high rigidity when a fiber-reinforced composite material is used. The tensile elastic modulus is more preferably 210 GPa or more, and further preferably 220 GPa or more. The higher the tensile elastic modulus, the better. However, if it is about 350 GPa, it is often sufficient for the purpose of the present invention. If the tensile modulus exceeds 400 GPa, the impact resistance of the fiber-reinforced composite material obtained may be reduced.

  Carbon fibers may also be used in combination with other reinforcing fibers. Examples of other reinforcing fibers include glass fibers, aramid fibers, boron fibers, alumina fibers, and silicon carbide fibers. Other reinforcing fibers can be mixed with carbon fibers as long as the object of the present invention is not impaired.

  In the present invention, the component (B) is not particularly limited as long as it is a monomer, oligomer or polymer having a generally known cationic polymerizable group. For example, vinyl resin, epoxy resin, bicycloorthoester resin, spiroortho Examples thereof include carbonate resins, thiirane resins, oxetane resins and the like.

  Among these, an epoxy resin, an oxetane resin, or a mixture thereof is preferably used because it has more heat resistance and active energy ray curability.

  As epoxy resins, phenyl glycidyl ether, p-tert-butylphenyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, 1,2-butylene oxide, 1,3-butadiene monooxide, 1,2 -Dodecylene oxide, epichlorohydrin, 1,2-epoxydecane, ethylene oxide, propylene oxide, styrene oxide, cyclohexene oxide, limonene oxide, α-pinene oxide, 3-methacryloyloxymethylcyclohexene oxide, 3-acryloyloxy Monofunctional monomers such as methylcyclohexene oxide and 3-vinylcyclohexene oxide, 1,1,3-tetradecadiene dioxide, Nendioxide, 4-vinylcyclohexene dioxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxycyclohexylpentyl-3,4-epoxycyclohexanecarboxylate, di (3,4- Epoxycyclohexyl) adipate, neopentyl glycol diglycidyl ether, glycerol polyglycidyl ether, bisphenol A type epoxy resin, tetrabromobisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin , O-, m-, p-cresol novolac type epoxy resin, phenol novolac type epoxy resin, naphthalene ring-containing epoxy resin, biphenyl type epoxy resin Poxy resin, biphenyl novolac type epoxy resin, dicyclopentadiene type epoxy resin, phenol aralkyl type epoxy resin, triphenylmethane type epoxy resin, isocyanate modified epoxy resin containing oxazolidone ring, tetraglycidyldiaminodiphenylmethane, triglycidylaminophenol, tetra Epoxy silicones such as glycidyl amine type epoxy resins such as glycidyl xylenediamine, glycidyl aniline, glycidyl o-toluidine, polyglycidyl ether of polyhydric alcohol, Shin-Etsu Silicone K-62-722 and Toshiba Silicone UV9300. And polyfunctional epoxy resins, and alicyclic epoxy resins.

  Oxetane resins include 3,3-dimethyloxetane, 3,3-bis (chloromethyl) oxetane, 2-hydroxymethyloxetane, 3-methyl-3-oxetanemethanol, 3-methyl-3-methoxymethyloxetane, 3- Ethyl-3-hydroxymethyloxetane, 1,4-bis {[(3-ethyl-3-oxetanyl) methoxy] methyl} benzene, 3-ethyl-3-phenoxymethyloxetane, resorcinol bis (3-methyl-3-oxetanyl) Ethyl) ether, m-xylylene bis (3-ethyl-3-oxetanylethyl ether), di [1-ethyl (3-oxetanyl)] methyl ether, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, 3 -Ethyl-3-{[3- (triethoxysilyl) propo Shi] methyl} oxetane, Oki Se Tani silsesquioxane, and the like phenol novolak type oxetane. These epoxy resins and oxetane resins may be used alone or in combination of two or more.

  The prepreg of the present invention can contain a polymerization accelerator, a polymer compound, and inorganic particles. A polymerization accelerator, a high molecular compound, and inorganic particles may be used independently and may use 2 or more types together.

  As the polymerization accelerator, alcohols such as ethylene glycol, 1,4-butanediol, glycerol, trimethylolpropane, pentaerythritol, polyvinyl alcohol, benzyl alcohol, and piperonyl alcohol are preferably used. By blending such a polymerization accelerator, there is an effect of improving the curing degree of cationic polymerization.

  As said high molecular compound, 1 or more types selected from the group which consists of a thermoplastic resin, a thermoplastic elastomer, and an elastomer is used preferably. By blending such a polymer compound, effects of controlling the viscosity of the resin, improving the handleability of the prepreg, improving the adhesion between the matrix resin and the carbon fiber, and / or improving the toughness are exhibited.

  As said thermoplastic resin, the thermoplastic resin which has a hydrogen bondable functional group from a compatible viewpoint with an epoxy resin and / or an oxetane resin and adhesiveness with carbon fiber is preferable. As the hydrogen bondable functional group, an alcoholic hydroxyl group, an amide group, an imide group, a sulfonyl group and the like are preferable.

  Specific examples include polyvinyl formal, polyvinyl butyral, polyamide, polyimide, polyetherimide, polysulfone, polyethersulfone, polyetherethersulfone, polyphenylsulfone, and polyurethane. Among these, the thermoplastic resins that do not inhibit cationic polymerization and are preferably used include polyvinyl formal, polyvinyl butyral, polyimide, polyetherimide, polysulfone, polyethersulfone, polyetherethersulfone, polythioethersulfone, and polyphenyl. A sulfone etc. can be mentioned. When the matrix resin is an epoxy resin, if polyamide or polyurethane is used, the effect of improving toughness is high. However, if polyamide or polyurethane is used, cations are likely to be trapped and curing may not proceed sufficiently in cationic polymerization. .

  Here, commercially available products include, for example, “Denka Butyral (registered trademark)” and “Denka Formal (registered trademark)” (manufactured by Denki Kagaku Kogyo Co., Ltd.), “Vinylec (registered trademark)” as polyvinyl butyral and polyvinyl formal. "Missin (registered trademark)" (Mitsui Chemicals) and "Ultem (registered trademark)" (manufactured by General Electric), "Matrimid" 5218 (manufactured by Chisso Corporation) and polyimide and polyetherimide Ciba), polysulfone and polyethersulfone, "UDEL (registered trademark)" (manufactured by Teijin Amoco) and "Sumika Excel (registered trademark)" (manufactured by Sumitomo Chemical Co., Ltd.), "RADEL (registered trademark) ) ”(Manufactured by Teijin Amoco) or the like can be used.

  In particular, in order to obtain good heat resistance, the glass transition temperature (Tg) of the thermoplastic resin is at least 150 ° C. or higher and preferably 170 ° C. or higher. If the glass transition temperature of the thermoplastic resin to be blended is less than 150 ° C., it may be easily deformed by heat when used as a molded body. Furthermore, as a terminal functional group of this thermoplastic resin, things, such as a hydroxyl group, a carboxyl group, a thiol group, and an acid anhydride, can react with a cationically polymerizable compound, and are used preferably. Specifically, "Sumika Excel (registered trademark)" PES3600P, "Sumika Excel (registered trademark)" PES5003P, "Sumika Excel (registered trademark)" PES5200P, and "Sumika Excel (registered trademark)" are commercially available polyethersulfone products. "PES7200P (above, manufactured by Sumitomo Chemical Co., Ltd.) and the like, and a copolymer oligomer of polyethersulfone and polyetherethersulfone as described in JP-T-2004-506789, Furthermore, “Ultem (registered trademark)” 1000, “Ultem (registered trademark)” 1010, “Ultem (registered trademark)” 1040 (manufactured by General Electric Co., Ltd.) and the like, which are commercially available polyetherimides, may be mentioned.

  The amount of the thermoplastic resin is preferably 0.5 to 50 parts by weight, more preferably 1 to 30 parts by weight, based on 100 parts by weight of the cationic polymerizable compound. If the blending amount of the thermoplastic resin is less than 0.5 parts by weight, the adhesive effect between the matrix resin and the carbon fiber may not be sufficient, and if it exceeds 50 parts by weight, the viscosity of the matrix resin composition excessively increases. However, workability may be reduced, or the strength may be reduced by coarse separation in a cured product.

  In addition, about 10 mg of thermoplastic resins are precisely weighed and the glass transition temperature is raised in accordance with JIS K7121 (2002) under conditions of a temperature range of 25 ° C. to 350 ° C. and a heating rate of 10 ° C./min. Measure the glass transition temperature at. Specifically, in the portion showing the step change of the obtained curve, the point where the straight line equidistant in the vertical axis direction from the extended straight line of each baseline intersects the curve of the step change portion of the glass transition Is the glass transition temperature.

  As the thermoplastic elastomer, a polyester-based or polyamide-based thermoplastic elastomer is preferably used. The thermoplastic elastomer here is a block copolymer composed of a hard segment component and a soft segment component, and is a polymer having a glass transition temperature below room temperature and a melting point above room temperature. The polyester-based or polyamide-based thermoplastic elastomer has a structure in which the hard segment component is a polyester unit or a polyamide unit. As these thermoplastic elastomers, for example, those described in International Publication No. 96/02592 pamphlet can be used.

  Many commercial products can also be used. Examples of commercially available polyester-based thermoplastic elastomers include Toray DuPont "Hytrel (registered trademark)", Toyobo "Belprene (registered trademark)", etc., and polyamide thermoplastic elastomers include ATOFINA “PEBAX (registered trademark)” of Mitsubishi Chemical Corporation and “NOVAMID (registered trademark)” of Mitsubishi Chemical Corporation.

  By blending the thermoplastic elastomer as described above, it is possible to obtain a prepreg excellent in adhesiveness (tackiness), deformability (draping property), and impregnation into carbon fibers. Further, compared to the case where such a thermoplastic elastomer is not blended, the temperature dependence of the viscoelastic function of the resin, particularly the change near room temperature is small, so the temperature dependence of the prepreg handling property is reduced, which is preferable. It is an aspect. In particular, in order to obtain a prepreg excellent in tackiness, drapeability and quality, it is preferable to blend 0.5 to 50 parts by weight of the thermoplastic elastomer with respect to 100 parts by weight of the cationic polymerizable compound.

  Further, as the elastomer, solid rubber, liquid rubber, rubber particles, and the like can be used. In general, solid rubber has a large increase in viscosity when dissolved in the same amount in a matrix resin compared to liquid rubber, and relatively maintains the heat resistance of the molded product while maintaining the matrix resin composition in the molding process at an appropriate viscosity level. can do. In particular, the temperature dependence of the viscoelastic function of the matrix resin is reduced, the handling property is less likely to deteriorate even if the working environment temperature changes when handling the prepreg, and the time-dependent change in tackiness due to leaving the prepreg is reduced, thereby reinforcing the fiber The surface smoothness of the composite material can be improved.

  As the solid rubber, an acrylonitrile-butadiene copolymer which is a random copolymer of butadiene and acrylonitrile is preferably used from the viewpoint of compatibility with the epoxy resin and / or the oxetane resin. By changing the copolymerization ratio of acrylonitrile, the compatibility with the epoxy resin and / or oxetane resin can be controlled. Furthermore, a solid rubber having a functional group is more preferably used in order to increase the adhesion with the epoxy resin and / or the oxetane resin. Examples of the functional group include a carboxyl group and an amino group. As the acrylonitrile-butadiene copolymer, a solid acrylonitrile-butadiene rubber containing a carboxyl group is particularly preferably used. Moreover, since it is excellent in a weather resistance, hydrogenated nitrile rubber is also preferably used.

  Commercially available products of these solid rubbers include “NIPOL (registered trademark)” 1072, “NIPOL (registered trademark)” 1072J, “NIPOL (registered trademark)” 1472, “NIPOL (registered trademark)” 1472HV, “NIPOL (registered trademark)”. "1042," NIPOL (registered trademark) "1043," NIPOL (registered trademark) "DN631," NIPOL (registered trademark) "1001," ZETPOL (registered trademark) "2020," ZETPOL (registered trademark) "2220," ZETPOL " (Registered trademark) "3110 (manufactured by Nippon Zeon Co., Ltd.).

  As the rubber particles, crosslinked rubber particles and core-shell rubber particles obtained by graft polymerization of a different polymer on the surface of the crosslinked rubber particles are preferably used. Commercially available crosslinked rubber particles include FX601P (made by JSR) made of a crosslinked product of carboxyl-modified butadiene-acrylonitrile copolymer, CX-MN series (made by Nippon Shokubai Co., Ltd.) made of acrylic rubber fine particles, YR. -500 series (manufactured by Toto Kasei Co., Ltd.) can be used. Commercially available core-shell rubber particles include “Paraloid (registered trademark)” EXL-2655 (manufactured by Kureha Chemical Industry Co., Ltd.) made of butadiene / alkyl methacrylate / styrene copolymer, acrylate / methacrylate ester "STAPHYLOID (registered trademark)" AC-3355 made of a polymer, TR-2122 (manufactured by Takeda Pharmaceutical Co., Ltd.), "PARALOID (registered trademark)" EXL- made of a butyl acrylate / methyl methacrylate copolymer 2611, EXL-3387 (manufactured by Rohm & Haas) and the like can be used.

  These rubber components tend to improve the toughness, but easily reduce the elastic modulus and heat resistance of the resin. Therefore, when blended, the addition amount is 0.1 to 30 parts by weight with respect to 100 parts by weight of the cationic polymerizable compound. The amount added is more preferably 1 to 20 parts by weight.

  As the inorganic particles, silica, alumina, smectite, synthetic mica, calcium carbonate, talc, clay, glass powder, aluminum hydroxide, titanium oxide, barium oxide and the like are preferable. These inorganic particles mainly have effects of rheological control such as thickening of the matrix resin composition and imparting thixotropy.

  The component (C) used in the present invention is not particularly limited as long as it can generate a Lewis acid by the action of active energy rays such as light, electron beam, and X-ray and / or heat. Various compounds such as Lewis acid diazonium salts, Lewis acid iodonium salts, Lewis acid sulfonium salts, Lewis acid selenonium salts, preferably Lewis acid iodonium salt compounds and / or Lewis acid sulfonium salts A compound is used. Constituent element (C) is different from other cationic polymerization initiators such as sulfonic acid esters, iron-arene compounds, silanol-aluminum complexes, and various Lewis acids generated by the action of active energy rays and / or heat. Cationic polymerization is possible with a wide range of monomers such as epoxides, cyclic ethers, cyclic acetals, lactones, vinyl monomers, cyclic siloxanes, etc., and the polymerization rate with various monomers, degree of cure, and the mechanical properties of the resulting matrix resin are also excellent. . In particular, in the prepreg of the present invention in which the component (D) described later is blended, the cationic polymerization initiator other than the component (C) increases the viscosity of the matrix resin and decreases the cationic polymerization rate and the degree of curing. The mechanical properties of the fiber reinforced composite material are reduced. Therefore, in the present invention, it is important to use the component (C), and this can improve the mechanical properties of various fiber-reinforced composite materials including compressive strength after impact.

  The component (C) may also be used as a mixture with other curing agents. Examples of other curing agents include polyamines, polyamidoamine resins and modified products thereof, acid anhydrides, novolac type phenol resins, polymercaptans, isocyanates, latent curing agents, radical polymerization initiators, and anionic polymerization initiators. Can do. Other curing agents can be mixed with the cationic polymerization initiator as long as the object of the present invention is not impaired.

  Examples of the iodonium salt compound of Lewis acid and / or the sulfonium salt compound of Lewis acid include arylsulfonium complex salts as described in US Pat. No. 4,231,951; and those described in US Pat. No. 4,256,828. Aromatic iodonium complex salts and aromatic sulfonium complex salts; aromatic sulfonium complex salts as described in JP-A-10-24496; aromatic iodonium complex salts as described in JP-A-11-263804 In the present invention, these can be used singly or in combination.

  Of these, an iodonium salt compound of Lewis acid represented by the general formula (1) is preferably used.

  Specific examples of the iodonium salt compound of the Lewis acid represented by the general formula (1) include the following compounds of the formula (2) to the formula (10). In the present invention, these may be used alone or in combination. Can be used in combination.

^(Wherein, R 1, ^{R 2} is a hydrogen atom, an alkyl group, any one of an alkoxy group, each of ^R 1, ^{R 2} may be the being the same or different, ^{and, R} 3, R ⁴ , R ⁵ and R ^{6 each} represent a hydrogen atom or an alkyl group, and each R ³ , R ⁴ , R ⁵ and R ⁶ may be the same or different from each other, and X is B (C ₆ F ₅ ) ₄ , SbF ₆ , AsF ₆ , PF ₆ , BF ₄ , CF ₃ SO ₃ , FSO ₃ , ClO ₄ , or F ₂ PO ₂ is shown.)
In the present invention, the component (C) is preferably blended in an amount of 0.01 to 20 parts by weight, more preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the component (B). If the amount of the component (C) is less than 0.01 parts by weight, the curability of the matrix resin composition due to active energy rays may decrease, and conversely if it exceeds 20 parts by weight, the cured product of the matrix resin composition In some cases, the mechanical properties of the matrix resin composition deteriorate, or the matrix resin composition undergoes a runaway reaction during curing with active energy rays. In particular, when the amount of component (C) is 0.1 to 10 parts by weight, the matrix resin composition can be cured safely and promptly upon curing with active energy rays, and the cured product of the matrix resin composition. Can improve the mechanical properties.

  The component (C) used in the present invention is a Lewis acid generated from the component (C) by the action of heat of reaction during the polymerization using the Lewis acid generated by the action of the active energy ray for the polymerization of the component (B). The acid can be used again for the polymerization of component (B).

  In the present invention, a photosensitizer can be used for the purpose of accelerating the cationic polymerization initiation reaction of the component (C). Examples of the photosensitizer include pigments such as acridine orange, acridine yellow, benzoflavin, cetoflavin T, and phosphine R, thioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4- Diethylthioxanthone, 2,4-diisopropylthioxanthone, thioxanthone derivatives, anthraquinone, anthraquinone derivatives, anthracene, 1,2-benzanthracene, dibutoxyanthracene, dipropoxyanthracene, anthracene derivatives, perylene, perylene derivatives, benzophenone, benzophenone Derivatives, pyrene, pyrene derivatives, phenothiazine, 2-chlorophenothiazine, 2-methoxyphenothiazine, phenothiazine derivatives, co Nene, coronene derivatives, benzophenone, benzophenone derivatives, camphorquinone, anthraquinone, 2-ethylanthraquinone, 9,10-anthraquinone, anthraquinone derivatives, fluorenone, 9-fluorenone, fluorenone derivatives, tetracene, tetracene derivatives, etc. In the present invention, these can be used singly or in combination. Among these, thioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, phenothiazine, 2-chlorophenothiazine, 2-methoxyphenothiazine, camphor Quinone, dibutoxyanthracene, and dipropoxyanthracene have special light absorption in the visible range, and are preferably used as a visible light initiator by mixing with the component (C) used in the present invention.

  The component (D) used in the present invention is a particle made of an organic material, preferably a particle made of a thermosetting resin and / or a thermoplastic resin. The particles comprising the thermosetting resin and / or thermoplastic resin used as the component (D) may be used alone or in combination of two or more.

  Such a thermosetting resin refers to any resin that is cured by heat or external energy such as light or electron beam to form a three-dimensional crosslinked body at least partially. Preferred thermosetting resins include epoxy resins, phenol resins, unsaturated polyester resins, amino resins, allyl resins, silicone resins, urethane resins, maleimide resins, polyimide resins, acetylene-terminated resins, allyl-terminated resins, and nadic. Examples thereof include resins having an acid terminal and resins having a cyanate ester terminal. Commercially available thermosetting resin particles include "Trepearl (registered trademark)" EP-B, "Trepearl (registered trademark)" EP-D, and "Trepearl (registered trademark)" EP-C, which are composed of crosslinked epoxy resin. “Trepearl (registered trademark)” EP-R, “Trepearl (registered trademark)” EP-M (manufactured by Toray Industries, Inc.) and the like can be used.

  The thermoplastic resin used as particles is a 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 in the main chain. A thermoplastic resin having a bond selected from the group consisting of

  Specific examples of such thermoplastic resins include vinyl resins such as polyacrylate, polyvinyl acetate, and polystyrene, polyamide, grillamide, polyaramid, polyester, polyacetal, polycarbonate, polyphenylene oxide, polyphenylene sulfide, and polyphenylene sulfide. Thermoplastic resins belonging to engineering plastics such as arylate, polybenzimidazole, polyimide, polyamideimide, polyetherimide, polysulfone, polyethersulfone, polyetheretherketone, hydrocarbon resins represented by polyethylene and polypropylene, cellulose acetate , And cellulose derivatives represented by entangled cellulose, a copolymer comprising methyl methacrylate-butyl acrylate-methyl methacrylate nanostrength (registered trademark) M22 (manufactured by Arkema Co., Ltd.), Nanostrength 123, Nanostrength 123, Nanostrength 250, Nanostrength 012, Nanostrength E20, Nanostrength E20 (manufactured by Nanostrength E20) It is done.

  In particular, polyamide, grillamide, polyaramid, polyester, polyacetal, polycarbonate, polyphenylene oxide, polyphenylene sulfide, polyarylate, polybenzimidazole, polyimide, polyamideimide, polyetherimide, polysulfone, polyethersulfone, polyphenylsulfone, polythioethersulfone, Since polyether ether ketone is excellent in impact resistance, it is suitable as a material for organic particles used in the present invention. Among these, organic particles containing chemical structures of primary amines and secondary amines have strong nucleophilicity and show basicity, so that cations are captured and the cationic polymerizability may be inhibited. In the case of using organic particles having the following chemical structure, it is preferable to use organic particles with a weak nucleophilicity containing a tertiary amine chemical structure, specifically, polyimides containing imide groups, polyetherimides, etc. It is good to use. More preferably, polysulfone, polyethersulfone, polythioethersulfone, polyetherethersulfone, polyphenylsulfone or the like composed of a sulfone group having a neutral chemical structure may be used. Of these, polyethersulfone and polyetherimide are highly suitable for cationic polymerization and toughness, and are particularly preferably used in the present invention.

  Commercially available products such as “Sumika Excel (registered trademark)” 5003P (manufactured by Sumitomo Chemical Co., Ltd.), “Ultrazone (registered trademark)” E3010, “Ultrazone (registered trademark)” are commercially available polyethersulfone products. ) “E2010 (above, BASF Engineering Plastics Co., Ltd.), polysulfone commercially available“ Ultrazone (registered trademark) ”S3010,“ Ultrazone (registered trademark) ”S2010 (above, BASF Engineering Plastics Co., Ltd.) "Udel (registered trademark)" P-3500, "Udel (registered trademark)" P-1700 (manufactured by Teijin Amoco Engineering Plastics Co., Ltd.), polyetherimide commercially available product "Ultem" 1000 , "Ultem (registered trademark)" 1010, "Ultem (registered trademark) Trademark) "1040 (or more, General Electric Co., Ltd.), and the like.

  Furthermore, particles in which two components of a thermosetting resin and a thermoplastic resin are mixed can also be used. For example, polyethersulfone, which is a thermoplastic resin with excellent toughness, bisphenol A type epoxy resin, tetrabromobisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy, which are thermosetting resins as plasticizers Resin, bisphenol S type epoxy resin, o-, m-, p-cresol novolak type epoxy resin, phenol novolac type epoxy resin, naphthalene ring-containing epoxy resin, biphenyl type epoxy resin, dicyclopentadiene type epoxy resin, phenol aralkyl type epoxy Resin, triphenylmethane type epoxy resin, isocyanate-modified epoxy resin containing oxazolidone ring, tetraglycidyldiaminodiphenylmethane, triglycidylaminophenol, tetraglycidyl Cyclohexylene diamine, can be used by mixing glycidyl aniline, at least one member selected from the group consisting of glycidyl amine type epoxy resins such as glycidyl o- toluidine.

  Since the component (D) used in the present invention is in the form of particles, it is mixed with a base resin (herein, the base resin represents components (B) and (C) other than the component (D)). In order to obtain a prepreg excellent in handleability without impairing the above-described tackiness and draping ability of the base resin used in the present invention. Can do. That is, by making the component (D) into particles, a wide range of materials can be selected.

  For this reason, even if the resin has been difficult to use as a matrix resin in spite of its excellent performance, it can be used as a component constituting the matrix resin by making it into particles. The performance can be improved.

  The shape of the component (D) used in the present invention is not limited to a spherical shape. Of course, it may be spherical, but there is no problem in various shapes such as powder obtained by pulverizing a resin lump or particles obtained by a spray drying method or a reprecipitation method. In addition, it may be in the form of a milled fiber obtained by cutting a fiber short, or may be in the shape of a needle or whisker. In particular, when it is desired to use spherical particles, the product obtained by the suspension polymerization method can be used as particles as it is.

  The size of the particle is expressed by a particle size. In this case, the particle size means a volume average particle size obtained by a centrifugal sedimentation rate method or the like.

  The volume average particle diameter of the component (D) used in the present invention is preferably 0.1 to 150 μm, more preferably 1 to 100 μm. When the particle diameter exceeds 150 μm, the physical properties of the fiber reinforced composite material are reduced because the arrangement of the carbon fibers is disturbed or the layers of the fiber reinforced composite material obtained by lamination are made thicker than necessary. There are disadvantages. Moreover, when this particle size is smaller than 0.1 micrometer, it may penetrate | invade in the inside of carbon fiber and it may become impossible to exist in the prepreg surface.

  The amount of component (D) must be in the range of 1-20% by weight in 100% by weight of prepreg. If it exceeds 20% by weight with respect to the prepreg, mixing with the base resin becomes difficult, and tackiness and drape of the prepreg deteriorate. In order to provide impact resistance by the particles while maintaining the properties of the base resin, the amount of the particles needs to be 20% by weight or less with respect to the prepreg, and more preferably 15% by weight or less. It is. In order to further improve the handling of the prepreg, the amount of the particles is preferably 10% by weight or less. In order to obtain high impact resistance, the amount of particles should be 1% by weight or more, preferably 2% by weight or more based on the prepreg.

  Regarding the distribution of the component (D), it is preferable that the prepreg surface layer, that is, between the prepreg sheet and the prepreg sheet when formed into a fiber-reinforced composite material, is offset. In highly anisotropic materials such as fiber reinforced composites, uniform stress is rarely generated throughout the material, and in most cases, the stress is concentrated in a specific portion. In particular, in the case of a fiber-reinforced composite material obtained by laminating sheet-like prepregs, it is known that a large stress is applied between sheets, that is, between layers, when an external force such as an external impact force is applied. Therefore, when particles having excellent toughness are distributed at a relatively high concentration between layers, a remarkable effect is brought about in improving the interlayer toughness.

  The usual addition of particles can only be expected to have a modification effect corresponding to the content of the particles relative to the matrix resin, but if the particles are offset from the surface layer of the prepreg, the additive properties described above are added. It is far beyond the expectation based on it, and especially with respect to the improvement of impact resistance, a remarkable effect that is completely unexpected can be obtained. The condition for satisfying this is that 90% or more of the particles are localized in a range of a depth of 30% of the thickness of the prepreg from the surface of the prepreg. If the particles are removed from the prepreg outside this condition, the impact resistance of the fiber reinforced composite material is inferior to that which meets the condition. A more pronounced effect appears when more than 90% of the particles are localized within a depth of 10% of the prepreg thickness from the prepreg surface.

  In the prepreg of the present invention, particles in which the particles are offset and distributed on both sides of the prepreg can be freely laminated regardless of the front and back of the prepreg. However, even if the prepreg has the same distribution of particles only on one side of the prepreg, the same effect can be obtained if the prepregs are laminated with care so that the particles are always placed between the prepregs. The present invention also includes a case where the particles are distributed on only one side.

  Evaluation of the distribution state of the particles in the prepreg is performed as follows. First, a prepreg is sandwiched and adhered between two smooth support plates, and gelled at a high temperature instantly. If the gelation is slow, the resin in the prepreg flows and the particles move, so that an accurate distribution state in the prepreg cannot be evaluated. After gelation, the prepreg is cured at a low temperature over time. Using this cured prepreg, the cross section is enlarged 200 times or more, and a photograph of 200 mm × 200 mm or more is taken. First, an average prepreg thickness is obtained using this cross-sectional photograph. The average thickness of the layer is measured at at least five points arbitrarily selected on the photograph, and the average is taken. Next, a line is drawn in parallel to the surface direction of the prepreg at a position of 30% of the thickness of the prepreg from the surface in contact with both support plates. Quantify the area of the particles existing between the surface that was in contact with the support plate and 30% parallel lines on both sides of the prepreg, determine the area of the particles existing over the entire width of the prepreg, and take the ratio Thus, the amount of particles existing within 30% of the thickness of the prepreg from the surface of the prepreg is calculated. The quantification of the particle area can be performed by cutting out all the particle portions existing in a predetermined region from the cross-sectional photograph and measuring the weight thereof, or by image analysis. As a specific example of image analysis, a digital image editing software (Adobe Photoshop 7.0, manufactured by Adobe Corporation) is used to binarize a particle portion existing in a predetermined region from a cross-sectional photograph and quantify the area. In order to eliminate the effects of partial variations in particles, this evaluation is performed over the entire width of the obtained photo, and the same evaluation is performed for five or more arbitrarily selected photos, and the average is calculated. I need to take it.

  Next, the manufacturing method of the prepreg of this invention is demonstrated. The prepreg according to the present invention is obtained by impregnating carbon fibers in the state of a sheet, ribbon, cloth, tape, or the like in which the uncured matrix resin used in the present invention is aligned in one direction. This prepreg can be prepared by dissolving the matrix resin in a solvent such as methyl ethyl ketone and methanol to lower the viscosity and impregnating the carbon fiber with a wet method, or the hot melt method in which the matrix resin composition is reduced in viscosity by heating and impregnated into the carbon fiber ( Manufactured by a method such as a dry method).

  In the wet method, carbon fibers are immersed in a liquid containing a matrix resin, and then the prepreg can be obtained by pulling up and evaporating the solvent using an oven or the like.

In the hot melt method, a film in which a matrix resin whose viscosity has been reduced by heating is directly impregnated into carbon fibers, or a film in which a composition containing the matrix resin is once coated on release paper or the like is first prepared, A prepreg impregnated with a matrix resin can be produced by stacking the film from both sides or one side and applying heat and pressure. The hot melt method is a preferable means because there is no solvent remaining in the prepreg.
The strength and elastic modulus of the resulting fiber reinforced composite material depend greatly on the amount of carbon fiber. In other words, when a certain amount of carbon fiber is contained, the weight of the product can be reduced while the performance of the fiber reinforced composite material or the final product is maintained substantially constant as the amount of the resin to be combined is reduced. For such purposes, the carbon fiber content with respect to the total weight of the prepreg and fiber-reinforced composite material in the present invention is preferably 40 to 90% by weight, more preferably 50 to 80% by weight, and still more preferably. Is 50 to 70% by weight. If the carbon fiber content is less than 40% by weight, the lightening effect may not be sufficient. If the carbon fiber content exceeds 90% by weight, the amount of resin is so small that voids remain in the fiber-reinforced composite material, resulting in poor mechanical properties. There is a case.

The weight per unit area of the carbon fiber used for the prepreg is preferably 10 to 400 g / m ² , more preferably 100 to 300 g / m ² . If the weight per unit area of the carbon fiber is less than 10 g / m ² , the prepreg is likely to be cracked, and the handleability is significantly deteriorated. Further, if the amount of rain per unit area of the carbon fiber exceeds 400 g / m ² , the resin does not reach the central portion in the thickness direction when impregnated, and becomes a prepreg having an unimpregnated portion, and voids remain when cured, The physical properties of the reinforced composite material may be reduced.

  In the prepreg of the present invention, when the composition containing the component (D) is impregnated, the particles do not penetrate into the carbon fiber, so that the particles are separated by filtration and can be localized on the prepreg surface as a result. . However, depending on the impregnation conditions, the localization of the particles on the prepreg surface may not be sufficient, and the impact resistance of the fiber-reinforced composite material may be reduced. Therefore, in order to reliably localize the particles on the prepreg surface, it is preferable to prepare the prepreg through a two-stage resin impregnation process. The two-stage resin impregnation process is a process in which a film having a matrix resin (base resin) composition excluding particles is coated on a release paper, and the film is laminated on both sides or one side of carbon fiber and heated and pressed. Impregnation to produce a primary prepreg. Next, a film of a matrix resin composition containing particles at a high concentration is coated on a release paper, and a resin film containing a high concentration of particles is stacked from both sides or one side of the primary prepreg and heated and pressed. Thus, a prepreg in which particles are reliably localized on the surface can be produced. In addition, after impregnating the carbon fiber with a matrix resin (base resin) excluding the particles, the target prepreg can be produced by evenly spraying the fine particles directly on the prepreg surface.

  The prepreg used in the present invention preferably has a gelation time at 160 ° C. within 180 minutes, more preferably within 120 minutes, and even more preferably within 90 minutes. If the gelation time exceeds 180 minutes, it may take a long time to cure, and may require long molding, or may not be cured and a fiber-reinforced composite material may not be obtained.

  Hereinafter, the present invention will be described more specifically with reference to examples. The methods for preparing the resin raw materials, prepregs and fiber reinforced composite materials used in the examples, and the evaluation methods of the compressive strength after impact and the gelation time are shown below. The composition of the resin composition used in each example, the compressive strength after impact, and the gelation time results are summarized in Table 1.

<Resin raw material>
For the preparation of the matrix resin composition, those selected from the following commercially available products and reagents were used.
(1) Cationic polymerizable compound “Epototo (registered trademark)” YD128 (manufactured by Toto Kasei Co., Ltd.): Bisphenol A type epoxy resin “Epiclon (registered trademark)” EXA-1514 (produced by Dainippon Ink Co., Ltd.) : Bisphenol S type epoxy resin NC-3000 (manufactured by Nippon Kayaku Co., Ltd.): Biphenyl novolac type epoxy resin (2) Thermoplastic resin “Sumika Excel (registered trademark)” 5003P (manufactured by Sumitomo Chemical Co., Ltd.): Polyethersulfone “Ultem (registered trademark)” 1010 (manufactured by General Electric Co., Ltd.): Polyetherimide CM4000 (manufactured by Toray Industries, Inc.): Polyamide (3) Cationic polymerization initiator “Lordsil (registered trademark)” 2074 (manufactured by Rhodia Japan): General formula (2)
The iodonium salt compound represented by these.
NAI-100 (manufactured by Midori Kagaku Co., Ltd.): sulfonic acid ester (4) organic particles “Sumika Excel (registered trademark)” 5003P (manufactured by Sumitomo Chemical Co., Ltd.): Polyethersulfone (volume average particle size 13 μm, 3 types (45μm and 180μm)
“Ultem (registered trademark)” 1010 (manufactured by General Electric Co., Ltd.): polyetherimide (volume average particle diameter: 37 μm)
"Ultrazone (registered trademark)" S3010 (manufactured by BASF Engineering Plastics): Polysulfone (volume average particle size 46 μm)
"Orgasol (registered trademark)" 2002 (manufactured by Nippon Rilsan Co., Ltd.): Polyamide (volume average particle size 12 μm)
SP-500 (manufactured by Toray Industries, Inc.): polyamide (volume average particle size 5 μm)
<Preparation of prepreg>
About Examples 1-7 and Comparative Examples 5-6 about the matrix resin composition shown in Table 1, the base resin except an organic particle is prepared, and the weight per unit area of resin is 31 g / m using a knife coater. ² was coated on release paper to prepare a resin film. This resin film is superimposed on both sides of carbon fiber (weight per unit area 190 g / m ² ) which is aligned in one direction, and a heat roll is used to impregnate the matrix resin composition while heating and pressing to obtain a primary prepreg. It was. Next, a matrix resin composition prepared by adding organic particles so that the final matrix resin composition of the prepreg is as shown in Table 1, using a knife coater at a weight of 21 g / m ² per unit area. A release film was coated to prepare a resin film. This resin film was superposed on both sides of the primary prepreg, and a heat roll was used to impregnate the resin while heating and pressing to obtain the desired prepreg.

For Example 8, a matrix resin composition shown in Table 1 was prepared, impregnated into carbon fibers (weight per unit area 190 g / m ² ), and the infiltration process was blocked by carbon fibers during the impregnation process. Organic particles were localized to obtain a prepreg.

About Comparative Examples 1-4, the matrix resin composition shown in Table 1 was prepared, and it coated on the release paper with the weight per unit area 52g / m < ² > using the knife coater, and produced the resin film. This resin film was superimposed on both sides of carbon fibers (weight per unit area 190 g / m ² ) that were aligned in one direction, and a heat roll was used to impregnate the matrix resin while heating and pressing to obtain the desired prepreg. . Further, for Comparative Example 4, organic particles were sprayed on one side of the prepreg so that the final matrix resin composition of the prepreg would be the amount shown in Table 1.

Here, the carbon fiber is “Torayca (registered trademark)” T700G (manufactured by Toray Industries, Inc., tensile elastic modulus: 240 GPa, tensile strength: 4.9 GPa, number of filaments: 24000, density: 1.80 g / cm ² ). Using.

<Particle abundance in 30% depth range>
The prepreg is sandwiched between two smooth fluororesin plates (for example, “Teflon (registered trademark)” plate) and closely adhered, gelled at 220 ° C., and then cured at 100 ° C. A cured resin product is produced. After curing, cut from the direction perpendicular to the contact surface, polish the cross section, enlarge it 200 times or more with an optical microscope, and take a picture so that the upper and lower surfaces of the prepreg are within the field of view. By the same operation, the distance between the fluororesin plates is measured at five points in the horizontal direction of the cross-sectional photograph, and the average value (n = 5) is taken as the thickness of the prepreg. Next, a line is drawn in parallel to the surface direction of the prepreg at a position of 30% of the thickness of the prepreg from the surface in contact with both support plates. Next, the total area of the fine particles existing between the surface of the prepreg and the above line and the total area of the fine particles existing over the thickness of the prepreg are obtained, and the thickness of the prepreg is 100% from the surface of the prepreg. The abundance ratio of the fine particles existing in the depth range of 30% is calculated. Here, the total area of the fine particles is obtained by cutting out the fine particle portion from the cross-sectional photograph and converting from the weight.

<Compressive strength after impact of fiber reinforced composite material>
The unidirectional prepreg produced by the above-described method is laminated in a configuration of (+ 45/0 / −45 / 90) 3 s, and heated in an autoclave at a temperature of 180 ° C. for 2 hours under a pressure of 0.59 MPa and a heating rate of 1 A fiber reinforced composite material was produced by molding at 5 ° C./min. According to JIS K7089 (1996), this fiber reinforced composite material was cut into a rectangle of 6 inches in the 0 ° direction and 4 inches in the 90 ° direction, with a drop height impact of 270 inch pounds at a fall height of 571 mm. And the compressive strength after impact was determined. The compression strength after impact was measured for five samples, and the average compression strength after impact was determined. Further, the measurement was performed in a room temperature dry state (25 ° C. ± 2 ° C., relative humidity 50%).

<Gelification time>
The gelation time of the prepreg at 160 ° C. was measured by measuring the gelation time of the matrix resin composition, and was measured as follows using a viscoelasticity measuring device (APA2000, manufactured by Alpha Technologies). First, an uncured matrix resin composition shown in Table 1 was injected into a viscoelasticity measuring apparatus whose temperature was set to 160 ° C., and a time-torque value curve of the matrix resin composition was measured. Here, the time-torque value curve refers to a curve obtained by taking time on the horizontal axis and torque values on the vertical axis. A heating time-torque value curve of a typical matrix resin composition thus measured is illustrated in FIG. In the present invention, the time during which the matrix resin composition was injected was 0 minute, and the time when the torque value was 1 [dN · m] as shown in FIG.

<Measurement results>
As shown in Table 1, it turned out that Examples 1-9 are excellent in compressive strength after impact compared with Comparative Examples 1-2, 4-5. In Comparative Example 3, the gelation time at 160 ° C. exceeded 180 minutes, the prepreg was not cured, and the compression strength after impact could not be measured. For Comparative Example 6, since a resin runaway reaction occurred during prepreg curing, a fiber-reinforced composite material could not be produced, and the compressive strength after impact could not be measured.

  The prepreg according to the present invention is particularly suitably used for spacecraft members such as aircraft members, satellites, rockets, spacecrafts, and automobile members.

It is a heating time-torque value curve figure of a typical matrix resin composition.

Claims (8)

A prepreg containing at least the following components (A), (B), (C), and (D), wherein 0.01 to 20 components (C) is added to 100 parts by weight of the component (B). A prepreg containing 1 part by weight, the component (D) being present in the prepreg in an amount of 1 to 20% by weight and being distributed at a higher concentration on the surface than in the prepreg.
(A) Carbon fiber (B) Cationic polymerizable compound (C) Onium salt of Lewis acid (D) Organic particles   The prepreg according to claim 1, wherein the component (C) is a sulfonium salt of Lewis acid and / or an iodonium salt of Lewis acid.   The prepreg in any one of Claims 1-2 which contain 0.1-10 weight part of components (C) with respect to 100 weight part of components (B).   The prepreg according to any one of claims 1 to 3, wherein the constituent element (D) is one or more kinds of particles selected from the group consisting of a thermoplastic resin, a thermoplastic elastomer and an elastomer.   The constituent element (D) is one or more kinds of particles selected from the group consisting of polysulfone, polyethersulfone, polythioethersulfone, polyetherethersulfone, polyphenylsulfone, polyimide, and polyetherimide. The prepreg as described.   The prepreg according to any one of claims 1 to 5, wherein the volume average particle diameter of the component (D) is in the range of 0.1 to 150 µm.   The prepreg according to any one of claims 1 to 6, wherein 90% or more of the component (D) is localized within 30% of the thickness from the surface of the prepreg.   The prepreg according to any one of claims 1 to 7, wherein the gelation time at 160 ° C is within 180 minutes.

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