Prepregs, laminates and integrally molded products

Abstract

The present invention addresses the problem of providing: a high-quality prepreg for manufacturing a laminate that is optimal as a structural material, the obtained laminate having a superior interlayer fracture toughness value, and being capable of being strongly fused to and integrated with other structural members; as well as said laminate. The present invention is a prepreg containing components [A], [B], and [C]. wherein [B] contains 10 mass% or more of a thermoplastic resin comprising an aromatic ring. A resin region containing [B] is present on one side of the prepreg, and a resin region containing [C] is present on another side thereof. [A] straddles an interface between the resin region containing [B] and the resin region containing [C], and contacts both resin regions. [A] Reinforcing fibers; [B] thermosetting resin; [C] thermoplastic resin

Description

[Technical Field]

[0001] The present invention relates to a prepreg in which reinforcing fibers are impregnated with a thermosetting resin and a thermoplastic resin, and to a laminate or an integrally molded article containing a thermosetting resin, a thermoplastic resin, and reinforcing fibers. [Background technology]

[0002] Fiber-reinforced composite materials, which combine thermosetting or thermoplastic resins as a matrix with reinforcing fibers such as carbon fiber or glass fiber, are lightweight yet offer excellent mechanical properties such as strength and rigidity, as well as heat and corrosion resistance. Therefore, they have been applied in numerous fields, including aerospace, automobiles, railway vehicles, ships, civil engineering and construction, and sporting goods. However, these fiber-reinforced composite materials are not suitable for the production of complex-shaped parts and structures in a single molding process. For these applications, it is necessary to fabricate components from the fiber-reinforced composite material and then integrate them with similar or dissimilar components. Mechanical joining methods, such as bolts, rivets, and screws, and adhesives, are commonly used to integrate fiber-reinforced composite materials composed of reinforcing fibers and thermosetting resins with similar or dissimilar components. Mechanical joining methods require pre-processing of the joints, such as drilling holes, which increases the manufacturing process time and costs. Furthermore, drilling holes reduces the material strength. Bonding methods that use adhesives require a bonding process that includes preparing the adhesive and applying the adhesive, as well as a curing process, which lengthens the manufacturing process and poses the problem of not being able to achieve satisfactory reliability in terms of adhesive strength. Fiber-reinforced composite materials using a thermoplastic resin as a matrix can be joined by welding, in addition to the mechanical joining methods and joining using adhesives mentioned above, which has the potential to shorten the time required to join components. However, when mechanical properties at high temperatures and excellent chemical resistance are required, such as in aircraft structural components, there is the issue that their heat resistance and chemical resistance are insufficient compared to fiber-reinforced composite materials made of thermosetting resins and reinforcing fibers.

[0003] Here, Patent Document 1 discloses a method of joining a fiber-reinforced composite material made of a thermosetting resin and reinforcing fibers with an adhesive. Patent Document 2 discloses a method for integrating a member made of a thermoplastic resin with a member made of a fiber-reinforced composite material made of a thermosetting resin. Specifically, a thermoplastic resin film is laminated on the surface of a prepreg sheet made of reinforcing fibers and a thermosetting resin, and a fiber-reinforced composite material is obtained by heating and pressurizing. The obtained fiber-reinforced composite material is then placed in a mold, and the thermoplastic resin is injection-molded to bond the thermoplastic resin member formed by injection molding to the fiber-reinforced composite material. Furthermore, Patent Document 3 discloses a method for manufacturing a laminate in which a thermoplastic resin adhesive layer is formed on the surface of a composite material made of a thermosetting resin and reinforcing fibers, and states that the laminate exhibits an adhesive effect with other components via the thermoplastic resin. Patent Document 4 discloses a prepreg in which particles, fibers, or a film made of a thermoplastic resin are arranged on the surface layer of a prepreg made of reinforcing fibers and a thermosetting resin, and a fiber-reinforced composite material thereof. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-161801 [Patent Document 2] Japanese Patent Application Publication No. 10-138354 [Patent Document 3] Patent No. 3906319 [Patent Document 4] Japanese Patent Application Publication No. 8-259713 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technique disclosed in Patent Document 1 is a method of joining fiber-reinforced composite materials made of reinforcing fibers and thermosetting resins together with an adhesive, and because the thermosetting resin is the matrix resin, welding cannot be applied as a method of joining fiber-reinforced composite materials as is. Since it takes time for the adhesive to harden, there is a problem in that the joining process takes time, and furthermore, the joint strength achieved is insufficient. In the method described in Patent Document 2, the bonding strength at the bonded portion between the thermosetting resin and the thermoplastic resin film in the fiber reinforced composite material was insufficient. The fiber-reinforced composite material according to Patent Document 3 can be integrated by welding via a thermoplastic resin, and exhibits excellent bonding strength at room temperature, but the bonding strength at high temperatures is insufficient. Patent Document 4 shows that particles, fibers, or films made of thermoplastic resins improve the interlaminar fracture toughness value, but this method does not provide sufficient bonding strength at the boundary between the thermosetting resin and the thermoplastic resin in the fiber-reinforced composite material.

[0006] Therefore, an object of the present invention is to provide a prepreg, a laminate, and an integrally molded product that have excellent quality as a prepreg, can be joined by welding to the same or different members, exhibits excellent bonding strength, and further has excellent interlaminar fracture toughness, and provides a laminate suitable as a structural material. [Means for solving the problem]

[0007] In order to solve this problem, the prepreg of the present invention has the following configuration: A prepreg containing the following components [A], [B], and [C], wherein [B] contains 10% by mass or more of a thermoplastic resin having an aromatic ring, a resin region containing [B] is present on one surface of the prepreg, and a resin region containing [C] is present on the other surface, and [A] is present across the boundary between the resin region containing [B] and the resin region containing [C] and in contact with both resin regions. [A] Reinforced fiber [B] Thermosetting resin [C]Thermoplastic resin

[0008] Furthermore, a laminate according to another aspect of the present invention has any one of the following configurations: a laminate in which at least some of the layers are constituted by a cured product of the prepreg described above, or a laminate having the following configuration: That is, a laminate including layers containing the following components [A], [C], and [D], wherein [D] contains 10% by mass or more of a thermoplastic resin having an aromatic ring, and [A] is present across the boundary between a resin region containing [C] and a resin region containing [D] and is in contact with both resin regions. [A] Reinforced fiber [C]Thermoplastic resin [D] Thermosetting resin cured product In this specification, unless otherwise specified, the term "laminate" refers to any of these laminates depending on the context. Although not particularly limited, as is clear from this specification, the laminate of the present invention is typically a fiber-reinforced resin that can be produced by using a preform containing the prepreg of the present invention. [Effects of the Invention]

[0009] The prepreg and laminate of the present invention utilize a thermosetting resin and a thermoplastic resin, which are firmly bonded together and can be welded to similar or dissimilar components. This shortens the time required for the bonding process compared to conventional fiber-reinforced composite materials consisting of a thermosetting resin and reinforcing fibers, enabling faster molding of structural components. Furthermore, the thermosetting resin contains a specified amount or more of a thermoplastic resin having an aromatic ring, providing favorable resin properties for the prepreg manufacturing process and producing high-quality prepregs. Additionally, the laminate exhibits excellent bonding strength and is an excellent structural material. Its applications include aircraft structural components, wind turbine blades, automotive structural components, and computer applications such as IC trays and laptop computer housings, demonstrating excellent structural performance and significantly reducing molding time and costs for the products involved. [Brief explanation of the drawings]

[0010] [Figure 1]3 is a schematic diagram of a prepreg or laminate according to the present invention, showing a cross section perpendicular to the plane of the prepreg or laminate according to FIG. 2. FIG. [Figure 2] FIG. 1 is a schematic diagram of a cross section perpendicular to the plane of a prepreg or laminate in the present invention, and is intended to help explain the method for measuring the roughness mean length RSm and the roughness mean height Rc. DETAILED DESCRIPTION OF THE INVENTION

[0011] <Component [A]> Examples of the reinforcing fibers used in the present invention as component [A] include glass fibers, carbon fibers, metal fibers, aromatic polyamide fibers, polyaramid fibers, alumina fibers, silicon carbide fibers, boron fibers, and basalt fibers. These may be used alone or in combination of two or more types. These reinforcing fibers may be surface-treated. Examples of surface treatments include metal deposition treatment, treatment with a coupling agent, treatment with a sizing agent, and treatment with an additive. In this specification, when reinforcing fibers have been surface-treated, the term "reinforcing fibers" includes those in a surface-treated state. These reinforcing fibers also include electrically conductive reinforcing fibers. Carbon fibers are preferably used as reinforcing fibers because of their low specific gravity, high strength, and high elastic modulus.

[0012] Commercially available carbon fibers include "TORAYCA (registered trademark)" T800G-24K, "TORAYCA (registered trademark)" T800S-24K, "TORAYCA (registered trademark)" T700G-24K, "TORAYCA (registered trademark)" T700S-24K, "TORAYCA (registered trademark)" T300-3K, and "TORAYCA (registered trademark)" T1100G-24K (all manufactured by Toray Industries, Inc.). The form and arrangement of the reinforcing fibers can be appropriately selected from those in which the reinforcing fibers are arranged in one direction, a laminate of reinforcing fibers arranged in one direction, or a woven fabric, etc., but in order to obtain a lightweight laminate with a higher level of durability, it is preferable that the reinforcing fibers in each prepreg be in the form of long fibers (fiber bundles) arranged in one direction or continuous fibers such as a woven fabric.

[0013] The reinforcing fiber bundle may be composed of a plurality of fibers of the same type, or may be composed of a plurality of fibers of different types. The number of reinforcing fibers constituting one reinforcing fiber bundle is usually 300 to 60,000, but in consideration of the production of the substrate, it is preferably 300 to 48,000, more preferably 1,000 to 24,000. The range may be a combination of any of the above upper and lower limits.

[0014] The reinforcing fiber has a surface free energy of 10 to 50 mJ / m as measured by the Wilhelmy method. 2 By controlling the surface free energy within this range, the reinforcing fibers exhibit high affinity with the thermosetting resin [B] or the cured thermosetting resin [D] and the thermoplastic resin [C], and high bonding strength is exhibited at the interface between the resin region containing [B] or [D] and the resin region containing [C], across which the reinforcing fibers are present. In addition, aggregation between the reinforcing fibers is suppressed, the dispersion of the reinforcing fibers in the molded product is improved, and the variation (coefficient of variation) in bonding strength is reduced. The surface free energy of the reinforcing fibers is preferably 15 to 40 mJ / m 2 , more preferably 18 to 35 mJ / m 2 is.

[0015] Methods for controlling the surface free energy of the reinforcing fibers include oxidizing the surface and adjusting the amount of oxygen-containing functional groups such as carboxyl groups and hydroxyl groups, or attaching a single compound or multiple compounds to the surface. When attaching multiple compounds to the surface, compounds with high and low surface free energy may be mixed and attached. Below, we will explain how to calculate the surface free energy of reinforcing fibers. The surface free energy can be calculated by measuring the contact angles of the reinforcing fibers with three types of solvents (purified water, ethylene glycol, and tricresyl phosphate) and then calculating the surface free energy using Owens' approximation formula. The procedure is shown below, but the measuring equipment and detailed method are not necessarily limited to those shown below.

[0016] Using a DataPhysics DCAT11, first, one single fiber is removed from the reinforcing fiber bundle and cut into eight pieces with a length of 12±2 mm. Then, the fibers are attached parallel to a dedicated holder FH12 (a flat plate with a surface coated with an adhesive substance) with 2-3 mm between each fiber. The tips of the single fibers are then trimmed and placed in the DCAT11 holder. For measurement, a cell containing each solvent is brought close to the bottom ends of the eight single fibers at a speed of 0.2 mm / s, immersing the fibers up to 5 mm from their tips. The single fibers are then pulled up at a speed of 0.2 mm / s. This procedure is repeated four or more times. The force F acting on the single fibers while immersed in the liquid is measured using an electronic balance. This value is used to calculate the contact angle θ using the following equation: COSθ = (force F (mN) acting on eight single fibers) / (8 (number of single fibers) × circumference of single fiber (m) × surface tension of solvent (mJ / m 2 )) The measurement was carried out on single fibers extracted from three different locations of the reinforcing fiber bundle. That is, the average contact angle was calculated for a total of 24 single fibers for one reinforcing fiber bundle.

[0017] Surface free energy γ of reinforcing fiber f is the polar component of the surface free energy γ p f , and the non-polar component of the surface free energy γ d f It is calculated as the sum of Polar component of surface free energy γ p f The non-polar component of the surface free energy γ is calculated by substituting the surface tension components and contact angle of each liquid into the Owens approximation formula shown below (a formula composed of the polar and non-polar components of the surface tension specific to each solvent, and the contact angle θ), plotting it on X and Y, and then approximating it linearly using the least squares method. d f is calculated by squaring the intercept b. The surface free energy of the reinforcing fiber γ f is the sum of the square of the slope a and the square of the intercept b. Y=a·X+b X = √(polar component of the surface tension of the solvent (mJ / m 2 )) / √(non-polar component of the solvent surface tension (mJ / m 2 ) Y = (1 + COSθ) (polar component of the surface tension of the solvent (mJ / m 2 )) / 2√(non-polar component of the solvent surface tension (mJ / m 2 ) The polar component of the surface free energy of the reinforcing fiber, γ p f =a 2 The non-polar component of the surface free energy of the reinforcing fiber, γ d f =b 2 Total surface free energy γ f =a 2 +b 2

[0018] The polar and non-polar components of the surface tension of each solvent are as follows: ·Purified water Surface tension 72.8mJ / m 2 , polar component 51.0mJ / m 2 , non-polar component 21.8 (mJ / m 2 ) Ethylene glycol Surface tension 48.0mJ / m 2 , polar component 19.0mJ / m 2 , non-polar component 29.0 (mJ / m 2 ) Tricresol phosphate Surface tension 40.9mJ / m 2 , polar component 1.7mJ / m 2 , nonpolar component 39.2 (mJ / m 2 )

[0019] <Component [B]> The thermosetting resin of component [B] used in the present invention contains 10% by mass or more of a thermoplastic resin having an aromatic ring. (In this specification, the term "thermosetting resin" as component [B] refers to a resin composition containing more than 50% by mass of a thermosetting resin and exhibiting the behavior of a thermosetting resin as a whole.) If the content of the thermoplastic resin having an aromatic ring is less than 10% by mass, resin removal onto the release paper or cover film occurs during the resin film production process and the carbon fiber resin impregnation process during prepreg production, resulting in increased unevenness in the thermosetting resin basis weight and preventing the production of high-quality prepregs. Increased resin basis weight unevenness leads to unevenness in the amount of thermosetting resin in the laminate, which in turn leads to unevenness in the proportion of reinforcing fibers and disturbances in the arrangement, resulting in increased variability (coefficient of variation) in the bond strength of the integrally molded product. More preferably, the content of the thermoplastic resin having an aromatic ring is 13% by mass or more. The thermoplastic resin component having such an aromatic ring is preferably a separate thermoplastic resin component different from the component [C] and soluble in the thermosetting resin [B]. Here, "soluble in a thermosetting resin" refers to the existence of a temperature range in which a homogeneous phase is formed when a mixture of the thermoplastic resin component and the thermosetting resin is heated or heated and stirred. Here, "forming a homogeneous phase" refers to a state in which no separation is visible to the naked eye. Here, "dissolved state" refers to a state in which a thermosetting resin containing a thermoplastic resin component forms a homogeneous phase when heated to a certain temperature range. Once a homogeneous phase is formed in a certain temperature range, separation may occur outside that temperature range, for example, at room temperature. The inclusion of such a thermoplastic resin having an aromatic ring increases the affinity with the thermoplastic resin [C], improving the interfacial strength between the resin region containing [B] or [D] and the resin region containing [C], resulting in excellent bonding strength as an integrally molded product.

[0020] The thermoplastic resin having an aromatic ring is generally preferably a thermoplastic resin having a bond in the main chain selected from the group consisting of carbon-carbon bonds, amide bonds, imide bonds, ester bonds, ether bonds, carbonate bonds, urethane bonds, thioether bonds, sulfone bonds, and carbonyl bonds. This thermoplastic resin component may have a partially crosslinked structure and may be crystalline or amorphous. Particularly preferred is at least one resin selected from the group consisting of polycarbonate, polyphenylene oxide, polyphenylene sulfide, polyarylate, polyester, polyamideimide, polyimide, polyetherimide polysulfone, polyethersulfone, polyetherketone, polyetheretherketone, phenoxy resin, and polybenzimidazole. Among these, the thermoplastic resin having an aromatic ring is preferably polyethersulfone or polyetherimide. Polyetherimide and polyethersulfone have strong interactions with the component [C] due to their hydrogen bonding properties, improving the interfacial strength between the resin region containing [B] or [D] and the resin region containing [C], thereby achieving excellent bonding strength in the integrated molded product. Furthermore, polyetherimide and polyethersulfone are excellent in heat resistance, and therefore demonstrate excellent bonding strength even in high-temperature environments, making them suitable examples.

[0021] The weight-average molecular weight of the aromatic ring-containing thermoplastic resin is preferably 10,000 g / mol or more and 40,000 g / mol or less. A weight-average molecular weight of 10,000 g / mol or more provides excellent heat resistance and mechanical properties as a thermoplastic resin, thereby exhibiting excellent bonding strength at room temperature and in high-temperature environments. A weight-average molecular weight of 40,000 g / mol or less enhances compatibility with component [C], improving the interfacial strength between the resin region containing [B] or [D] and the resin region containing [C], thereby exhibiting excellent bonding strength.

[0022] Component [B] preferably has a storage modulus of 1.0 to 100 Pa at 90°C during a temperature rise at 1.5°C / min using a rheometer. When [B] has a storage modulus of 1.0 Pa or more at 90°C, the thermosetting resin film production process and the carbon fiber resin impregnation process during prepreg production result in less resin transfer to the release paper or cover film, enabling the production of a high-quality prepreg with minimal resin basis weight variation. Furthermore, when component [B] has a storage modulus of 100 Pa or less at 90°C, the thermosetting resin film production process during prepreg production results in a resin film with a uniform thickness without resin smearing, enabling the production of a high-quality prepreg with minimal resin basis weight variation. Minimizing resin basis weight variation reduces bias in the amount of thermosetting resin in the laminate and suppresses the formation of defects such as voids, making it possible to keep the variation (coefficient of variation) in the bonding strength of the integrally molded product low. The storage modulus at 90°C is more preferably 1.0 to 50 Pa, and further preferably 1.0 to 30 Pa.

[0023] Furthermore, the temperature at which component [B] reaches its minimum viscosity during a temperature increase at 1.5°C / min is preferably in the range of 120°C or higher. This reduces resin viscosity during the prepreg manufacturing process, allowing for the production of a resin film with uniform thickness and minimal resin weight variation, resulting in a high-quality prepreg. Here, during the temperature increase at 1.5°C / min using a rheometer, component [B] gradually decreases in viscosity. However, as the temperature increases, the curing reaction progresses and the material becomes less fluid. Therefore, once a certain temperature is exceeded, the viscosity begins to increase. This temperature was defined as the temperature at which the minimum viscosity is reached, and the viscosity just before the viscosity begins to increase was defined as the minimum viscosity. From the perspective of manufacturing efficiency, the temperature at which the minimum viscosity is reached is preferably 180°C or lower. Furthermore, if the minimum viscosity is 0.5 Pa·s or higher, the alignment of the carbon fibers is less likely to be disrupted during laminate molding, allowing the integrated molded product to exhibit high bonding strength and minimize bonding strength variation. The minimum viscosity when heated at a rate of 1.5°C / min using a rheometer is more preferably 1.0 Pa s or more, and even more preferably 2.0 Pa s or more. From the viewpoint of the quality of the laminate obtained after molding, the minimum viscosity is 100 Pa s or less, and more preferably 10 Pa s or less.

[0024] Examples of thermosetting resins used in component [B] include unsaturated polyester resins, vinyl ester resins, epoxy resins, phenolic resins, urea resins, melamine resins, polyimide resins, cyanate ester resins, bismaleimide resins, benzoxazine resins, copolymers or modified products thereof, and resins obtained by blending at least two of these. To improve impact resistance, an elastomer or rubber component may be added to the thermosetting resin. Among these, epoxy resins are preferred due to their excellent mechanical properties, heat resistance, and adhesion to reinforcing fibers. Examples of the base resin of the epoxy resin include bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD ​​type epoxy resin, and bisphenol S type epoxy resin; brominated epoxy resins such as tetrabromobisphenol A diglycidyl ether; epoxy resins having a biphenyl skeleton, epoxy resins having a naphthalene skeleton, epoxy resins having a dicyclopentadiene skeleton; novolac type epoxy resins such as phenol novolac type epoxy resin and cresol novolac type epoxy resin; Examples of epoxy resins include glycidyl amine type epoxy resins such as phenol, N,N,O-triglycidyl-p-aminophenol, N,N,O-triglycidyl-4-amino-3-methylphenol, N,N,N',N'-tetraglycidyl-4,4'-methylenedianiline, N,N,N',N'-tetraglycidyl-2,2'-diethyl-4,4'-methylenedianiline, N,N,N',N'-tetraglycidyl-m-xylylenediamine, N,N-diglycidylaniline, and N,N-diglycidyl-o-toluidine; resorcinol diglycidyl ether; and triglycidyl isocyanurate.

[0025] The thermosetting resin used in component [B] of the present invention preferably contains an epoxy resin. A more preferred embodiment involves the inclusion of 40 to 100 parts by mass of a glycidylamine-type epoxy resin containing three or more glycidyl groups per 100 parts by mass of the total epoxy resin contained in the thermosetting resin, as this provides a cured product with high heat resistance. Examples of glycidylamine-type epoxy resins containing three or more glycidyl groups include N,N,O-triglycidyl-m-aminophenol, N,N,O-triglycidyl-p-aminophenol, N,N,O-triglycidyl-4-amino-3-methylphenol, N,N,N',N'-tetraglycidyl-4,4'-methylenedianiline, N,N,N',N'-tetraglycidyl-2,2'-diethyl-4,4'-methylenedianiline, and N,N,N',N'-tetraglycidyl-m-xylylenediamine.

[0026] Examples of the curing agent for the epoxy resin contained in component [B] include dicyandiamide, aromatic amine compounds, phenol novolac resins, cresol novolac resins, polyphenol compounds, imidazole derivatives, tetramethylguanidine, thiourea-added amines, carboxylic acid hydrazides, carboxylic acid amides, and polymercaptans. In particular, by using an aromatic amine curing agent as a curing agent for an epoxy resin, an epoxy resin having good heat resistance can be obtained. Examples of the aromatic amine compound include 3,3'-diisopropyl-4,4'-diaminodiphenyl sulfone, 3,3'-di-t-butyl-4,4'-diaminodiphenyl sulfone, 3,3'-diethyl-5,5'-dimethyl-4,4'-diaminodiphenyl sulfone, 3,3'-diisopropyl-5,5'-dimethyl-4,4'-diaminodiphenyl sulfone, 3,3'-di-t-butyl-5,5'-dimethyl-4,4'-diaminodiphenyl sulfone, 3,3',5,5'-tetraethyl-4,4'-diaminodiphenyl sulfone, 3,3'-di Examples thereof include isopropyl-5,5'-diethyl-4,4'-diaminodiphenyl sulfone, 3,3'-di-t-butyl-5,5'-diethyl-4,4'-diaminodiphenyl sulfone, 3,3',5,5'-tetraisopropyl-4,4'-diaminodiphenyl sulfone, 3,3'-di-t-butyl-5,5'-diisopropyl-4,4'-diaminodiphenyl sulfone, 3,3',5,5'-tetra-t-butyl-4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, and 3,3'-diaminodiphenyl sulfone.

[0027] The cured thermosetting resin of component [D] in the laminate of the present invention is typically obtained by heat-curing the thermosetting resin of component [B] in the prepreg of the present invention. The temperature conditions for heat-curing can be appropriately set depending on the type of thermosetting resin and the types and amounts of curing agent and accelerator. For example, when an epoxy resin is used as the thermosetting resin and diaminodiphenyl sulfone is used as the amine compound, temperature conditions of 180°C for 2 hours can be suitably used.

[0028] <Component [C]> The thermoplastic resin constituting component [C] (in this specification, the term "thermoplastic resin" as component [C] refers to a resin composition containing more than 50% by mass of a thermoplastic resin and exhibiting the behavior of a thermoplastic resin as a whole) is not particularly limited, and examples thereof include polyester-based resins such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, and liquid crystal polyester; polyolefins such as polyethylene, polypropylene, and polybutylene; styrene-based resins; urethane resins; polyoxymethylene; polyamides such as polyamide 6 and polyamide 66; polycarbonate; polymethyl methacrylate; polyvinyl chloride; polyphenylene sulfide; polyphenylene ether; modified polyphenylene ether; polyimide; polyamideimide; polyetherimide; polysulfone; modified polysulfone; polyethersulfone; polyarylene ether ketones such as polyketone, polyether ketone, polyether ether ketone, and polyether ketone ketone; polyarylate; polyether nitrile; phenolic resins; and phenoxy resins. These thermoplastic resins may be copolymers or modified products of the above-mentioned resins, and / or resins obtained by blending two or more of them. Among these, it is preferable that [C] is one or more selected from polyamide, polyarylene ether ketone, polyphenylene sulfide, polyether sulfone, and polyether imide, since this has excellent heat resistance and allows the integrally molded product to exhibit high bonding strength even in a high-temperature environment.

[0029] Furthermore, if the thermoplastic resin constituting [C] is a crystalline thermoplastic resin, the viscosity at a temperature 40°C higher than the melting point is preferably 1,000 Pa·s or more and 100,000 Pa·s or less at a temperature 40°C higher than the glass transition temperature is preferably 1,000 Pa·s or more and 100,000 Pa·s or less when the thermoplastic resin constituting [C] is a crystalline thermoplastic resin, and the viscosity at a temperature 40°C higher than the glass transition temperature is preferably 1,000 Pa·s or more and 10,000 Pa·s or less when the thermoplastic resin is an amorphous thermoplastic resin, because this can suppress the flow of the resin [C] when joining by welding using the surfaces where component [C] is present, thereby achieving excellent joining strength. The viscosity is more preferably 1,000 Pa·s or more and 10,000 Pa·s or less. Furthermore, an elastomer or rubber component may be added to component [C] to improve impact resistance. Furthermore, depending on the intended use, other fillers or additives may be appropriately added within the scope of the present invention. Examples of such additives include inorganic fillers, flame retardants, conductivity imparting agents, crystal nucleating agents, UV absorbers, antioxidants, vibration dampers, antibacterial agents, insect repellents, deodorizing agents, color inhibitors, heat stabilizers, release agents, antistatic agents, plasticizers, lubricants, colorants, pigments, dyes, foaming agents, foam control agents, and coupling agents.

[0030] <Prepreg> The prepreg of the present invention has a resin region containing [B] on one surface and a resin region containing [C] on the other surface. Furthermore, in the prepreg of the present invention, reinforcing fibers of [A] are present across the interface between the resin region containing [B] and the resin region containing [C], contacting both resin regions. The presence of reinforcing fibers of [A] across the interface between the resin region containing [B] and the resin region containing [C] allows [A] to chemically and / or physically bond with [B] and [C], making it difficult for the resin region containing [B] to peel from the resin region containing [C], thereby improving bonding strength. Furthermore, the chemical and / or physical bonding of component [A], which contacts both resin regions across the interface, with component [B] and component [C] improves adhesion between the resin region containing component [B] and the resin region containing component [C].

[0031] In the prepreg of the present invention, it is preferable that the resin region containing [B] and the resin region containing [C] are adjacent to each other in layers. Figure 1 is a schematic diagram of the prepreg or laminate of the present invention, and Figure 2 is a schematic diagram of a cross section perpendicular to the prepreg plane or laminate plane shown as cross-sectional observation plane 5 in Figure 1. In the prepreg of the present invention, being adjacent in a layered state means, for example, as shown in Fig. 2, in a cross section obtained by cutting the prepreg perpendicular to the plane direction, that resin region 7 containing [C] and resin region 8 containing [B] that are continuous in the plane direction are in close contact with each other while forming boundary surface 10. If resin region 7 containing [C] is not continuous in a layered state but is present in the form of particles, fibers, nonwoven fabric, or the like, the proportion of the area where the thermosetting resin [B] is exposed on the surface increases and the coverage of [C] on the outermost surface decreases, which tends to reduce weldability.

[0032] Furthermore, when the prepreg is viewed in plan, it is preferable from the viewpoint of improving bonding strength that in a cross section perpendicular to the plane of the prepreg containing the fibers of [A] existing across both resin regions, that is, a cross section obtained by cutting perpendicularly to the plane direction of the prepreg from a direction at an angle of 45 degrees, either clockwise or counterclockwise, with respect to the fiber direction of any [A] that contacts both resin regions, the roughness average length RSm of the cross section curve formed by the interface between both resins as defined in JIS B0601 (2001) is 100 μm or less and the roughness average height Rc is 3.5 μm or more. When the roughness average length RSm is 100 μm or less, not only chemical and / or physical bonding forces but also a mechanical bonding force called entanglement are added, making it difficult for the resin region containing the component [B] to peel from the resin region containing the component [C]. The lower limit is not particularly limited, but is preferably 15 μm or more from the viewpoint of avoiding a decrease in mechanical bonding force due to stress concentration. Furthermore, when the roughness average height Rc of the cross-sectional curve is 3.5 μm or more, not only the mechanical bonding force caused by entanglement is exhibited, but also the component [A], which contacts both resin regions across the interface, chemically and / or physically bonds with the component [B] and the component [C], thereby improving the adhesion between the resin region containing the component [B] and the resin region containing the component [C]. The preferred range of the roughness average height Rc of the cross-sectional curve is 10 μm or more, which facilitates contact of the component [A] with both resin regions and further improves the adhesion, and is particularly preferably 20 μm or more. The upper limit is not particularly limited, but is preferably 100 μm or less from the viewpoint of avoiding a decrease in mechanical bonding strength due to stress concentration.

[0033] Here, the roughness mean height Rc and roughness mean length RSm of the cross-sectional curve can be measured by known methods. Examples include a method of measuring from a cross-sectional image acquired using X-ray CT after curing component [B], a method of measuring from an elemental analysis mapping image obtained by an energy dispersive X-ray spectrometer (EDS), or a method of measuring from a cross-sectional observation image obtained by an optical microscope, a scanning electron microscope (SEM), or a transmission electron microscope (TEM). In the observation, component [B] and / or component [C] may be stained to adjust the contrast. In an image obtained by any of the above methods, the roughness mean height Rc and roughness mean length RSm of the cross-sectional curve are measured within a 500 μm square area.

[0034] An example of a method for measuring the roughness mean height Rc and roughness mean length RSm of a cross-sectional curve is shown in Fig. 2. In the observed image 9 shown in Fig. 2, a resin region 7 containing the component [C] is in close contact with a resin region 8 containing the component [B], which is shown as an interface 10 in the observed image 9. In addition, a plurality of components [A] 6 are present on the interface 10. This shows an example of a method for measuring the roughness mean height Rc and roughness mean length RSm of a cross-sectional curve 13 (cross-sectional curve element measurement method 1). The end of the rectangular observation image 9 on the side of the resin region 8 containing the component [B] is set as a reference line 11, and vertical base lines 12 are drawn at 5 μm intervals from the resin region 8 containing the component [B] toward the resin region 7 containing the component [C]. The point where the vertical base line 12 drawn from the reference line 11 first intersects with the component [C] is plotted, and the line connecting the plotted points is defined as the cross-sectional curve 13. The obtained cross-sectional curve 13 is subjected to a filtering process based on JIS B0601 (2001), and the roughness mean height Rc and roughness mean length RSm of the cross-sectional curve 13 are calculated.

[0035] In the prepreg of the present invention, the basis weight of the thermoplastic resin of the component [C] is 10 g / m 2 It is preferable that the thickness is 10 g / m or more. 2 A thickness of 20 g / m or more is preferable because it is sufficient to achieve excellent bonding strength. 2 The upper limit is not particularly limited, but is preferably 500 g / m because the amount of thermoplastic resin is not too large compared to the reinforcing fibers and a laminate excellent in specific strength and specific modulus can be obtained. 2 Here, the basis weight is the weight per 1 m of prepreg. 2 This refers to the mass (g) of the component [C] contained per unit mass.

[0036] The prepreg of the present invention has a reinforcing fiber amount per unit area of ​​30 to 2,000 g / m 2 It is preferable that the amount of reinforcing fibers is 30 g / m 2 When the amount of reinforcing fibers is 2,000 g / m or more, the number of layers to be laminated to obtain a predetermined thickness during laminate molding can be reduced, which tends to simplify the work. 2If it is less than this, the drapeability of the prepreg is likely to be improved. The reinforcing fiber mass content of the prepreg of the present invention is preferably 30 to 90 mass%, more preferably 35 to 85 mass%, and even more preferably 40 to 80 mass%. It may be within a range that combines any of the above upper and lower limits. When the reinforcing fiber mass content is 30 mass% or more, the amount of resin relative to the fibers is not too high, making it easier to obtain the advantages of a laminate with excellent specific strength and specific modulus. Furthermore, when the laminate is molded, the amount of heat generated during curing is less likely to be excessively high. Furthermore, when the reinforcing fiber mass content is 90 mass% or less, impregnation failure with the resin is less likely to occur, and the resulting laminate is more likely to have fewer voids.

[0037] <Laminate> Another aspect of the present invention is a laminate produced by a method of curing, under pressure and heat, a preform in which at least some layers are made of the prepreg of the present invention, which preform is produced by laminating multiple sheets of the prepreg of the present invention described above or by laminating the prepreg of the present invention together with a prepreg other than the prepreg of the present invention, i.e., a laminate in which at least some layers are made of a cured product of the prepreg of the present invention described above. Here, methods for applying heat and pressure include, for example, press molding, autoclave molding, bagging molding, wrapping tape molding, and internal pressure molding. Alternatively, yet another aspect of the present invention is a laminate comprising layers containing the components [A], [C], and [D], wherein [D] contains 10 mass% or more of a thermoplastic resin having an aromatic ring, and wherein the reinforcing fibers of [A] are present across the boundary between a resin region containing [C] and a resin region containing [D] and are in contact with both resin regions.

[0038] When the laminate is viewed in plan, a cross section perpendicular to the plane of the laminate containing [A] present across both resin regions, i.e., a cross section obtained by cutting perpendicular to the plane of the laminate from a direction at an angle of 45 degrees, either clockwise or counterclockwise, relative to the fiber direction of any [A] that contacts both resin regions, preferably has a roughness mean length RSm of 100 μm or less and a roughness mean height Rc of 3.5 μm or more, as defined by JIS B0601 (2001). It is more preferable that the roughness mean height Rc be 10 μm or more. While the lower limit of RSm and the upper limit of Rc are not particularly limited, RSm is preferably 15 μm or more, and Rc is preferably 100 μm or less, in consideration of concerns about reduced mechanical bonding strength due to stress concentration. The roughness average height Rc and roughness average length RSm of the cross-sectional curve can be measured by the above-mentioned method, similar to the measurement method for the prepreg of the present invention.

[0039] The laminate of the present invention can be produced by a molding method such as press molding, autoclave molding, bagging molding, wrapping tape molding, internal pressure molding, hand lay-up, filament winding, pultrusion, resin injection molding, or resin transfer molding. The laminate of the present invention preferably has the thermoplastic resin of component [C] present on the surface, i.e., has a layer containing [A], [C], and [D] as the outermost layer, with [C] exposed. Furthermore, the laminate of the present invention preferably has the component [C] present both on the surface and in the interior, i.e., has a layer containing [A], [C], and [D] as an inner layer as well. The presence of the thermoplastic resin of component [C] on the surface of the laminate allows the laminate of the present invention to be joined to the same or different members by welding via the component [C]. On the other hand, the presence of the thermoplastic resin of component [C] also in the interior of the laminate allows the laminate to have an excellent interlaminar fracture toughness value (G IIC ) is obtained.

[0040] <Integrated molded product> The laminate of the present invention can be formed into an integrated molded article by joining another member (i.e., a member (adherend) of the same type and / or a different type from the member constituting the laminate to the surface where [C] is present, particularly to the component [C] present on the surface of the laminate, using some kind of heating means. The different member (adherend) can be a member made of a thermoplastic resin or a member made of a metal material. The thermoplastic resin member may contain reinforcing fibers, fillers, etc. The integration method is not particularly limited, and examples include heat welding, vibration welding, ultrasonic welding, laser welding, resistance welding, induction welding, insert injection molding, and outsert injection molding.

[0041] The strength of the joints of integrally molded products can be evaluated according to ISO4587:1995 (JIS K6850(1994)). The tensile shear bond strength measured according to ISO4587:1995 is preferably 25 MPa or more, more preferably 28 MPa or more, at a test ambient temperature of 23°C. Generally, a tensile shear bond strength of 20 MPa or more allows the laminate to be used for bonding structural materials, and is higher than the tensile shear bond strength (approximately 10 MPa) of a typical adhesive at a test ambient temperature of 23°C. For applications requiring mechanical properties in high-temperature environments, a bond strength of 13 MPa or more, more preferably 16 MPa or more, as evaluated according to ISO4587:1995 at a test ambient temperature of 80°C is preferred. The higher the tensile shear bond strength, the better. There is no particular upper limit. However, for typical integrally molded laminate products, the tensile shear bond strength at test ambient temperatures of 23°C or 80°C is typically 200 MPa.

[0042] The laminate of the present invention is preferably used in aircraft structural members, wind turbine blades, automobile outer panels, computer applications such as IC trays and notebook computer housings, and sports applications such as golf shafts and tennis rackets. [Example]

[0043] The present invention will be described in more detail below with reference to examples. However, the scope of the present invention is not limited to these examples. The unit "parts" used in the composition ratios means parts by mass unless otherwise noted. Furthermore, measurements of various properties were carried out in an environment of 23°C and 50% relative humidity unless otherwise noted.

[0044] <Materials used as reinforcing fibers for component [A]> The raw material, carbon fiber bundles, were obtained by the following method, and then various sizing compounds were applied. First, acrylonitrile copolymers copolymerized with itaconic acid were spun and baked to obtain a total of 24,000 filaments with a specific gravity of 1.8 g / cm. 3 A carbon fiber bundle with a strand tensile strength of 4.9 GPa and a strand tensile modulus of 230 GPa was obtained. Various sizing agent compounds were then mixed with acetone to obtain a solution of approximately 1% by mass in which the compounds were uniformly dissolved. Each compound was applied to the carbon fiber bundle by immersion, and then heat-treated at 210°C for 90 seconds, adjusting the amount of each compound attached to 0.5 parts by mass per 100 parts by mass of the carbon fiber to which the compound was attached. The sizing agent compounds used for each carbon fiber and the surface free energy after application of the sizing agent are as follows: CF1: polyethylene glycol diglycidyl ether (Denacol (registered trademark) EX-841, manufactured by Nagase ChemteX Corporation), surface free energy: 20 mJ / m 2 CF2: bisphenol A diglycidyl ether ("jER" (registered trademark) 828, manufactured by Mitsubishi Chemical Corporation), surface free energy: 9 mJ / m 2 CF3: sorbitol polyglycidyl ether (Denacol (registered trademark) EX-614B, manufactured by Nagase ChemteX Corporation), surface free energy: 32 mJ / m 2

[0045] <Method for preparing and evaluating thermosetting resin of component [B]> The thermosetting resins of the specific examples shown in Table 1 were prepared using the following compounds (1) to (4) by the method described in (5), and evaluated by the method described in (6). (1) Epoxy resin Tetraglycidyldiaminodiphenylmethane ("Araldite" (registered trademark) MY721, manufactured by Huntsman Advanced Materials, epoxy equivalent: 113 (g / eq.), tetrafunctional glycidylamine-type epoxy resin) Bisphenol F epoxy resin (Epc® 830, manufactured by DIC Corporation) epoxy equivalent: 170 (g / eq.) (2) Amine compounds 4,4'-Diaminodiphenyl sulfone (Seikacure S, manufactured by Wakayama Seika Kogyo Co., Ltd.) Dicyandiamide (DICY7, manufactured by Mitsubishi Chemical Corporation) (3) Curing catalyst 3-(3,4-Dichlorophenyl)1,1-dimethylurea (DCMU99, manufactured by Hodogaya Chemical Co., Ltd.) (4) Thermoplastic resins containing aromatic rings Polyethersulfone ("Sumikaexcel" (registered trademark) PES5003P, manufactured by Sumitomo Chemical Co., Ltd., weight-average molecular weight 47,300 g / mol) Polyethersulfone (Virantage 10700RFP, Solvay, weight average molecular weight 21,000 g / mol)

[0046] (5) Method for preparing thermosetting resin The epoxy resin and viscosity modifier listed in Table 1 were placed in a kneading device and heated and kneaded to dissolve the viscosity modifier (although in some cases the viscosity modifier was not added). Next, while continuing to knead, the temperature was lowered to 100°C or less, and an amine compound and a curing catalyst appropriately selected from those listed in Table 1 (in some cases the curing catalyst was not added) were added and stirred to obtain thermosetting resins B-1 to B-7. (6) Viscoelasticity measurement method for thermosetting resins The viscoelasticity of thermosetting resins was measured using a dynamic viscoelasticity analyzer, ARES-G2 (manufactured by TA Instruments). Using 40 mm diameter parallel plates as the upper and lower measuring jigs, the resin was set so that the distance between the upper and lower jigs was 1 mm, and measurements were taken at a strain rate of 3.14 rad / s. The temperature was raised from 20°C to 170°C at a rate of 1.5°C / min, and the storage modulus and minimum viscosity at 90°C, as well as the temperature at that time, were recorded. The viscosity increase ratio at 90°C was also calculated using the following formula after setting the jigs and resin in the same way as above, at a temperature of 90°C and a strain rate of 3.14 rad / s. 90°C viscosity increase ratio (times) = (viscosity after 3 hours) / (viscosity at the start of measurement)

[0047] <Materials used as thermoplastic resin for component [C] and evaluation method> The thermoplastic resins used in Tables 2 and 3 were as follows: PA6: Polyamide 6 ("Amilan" (registered trademark) CM1007 (manufactured by Toray Industries, Inc., melting point 225°C)) with a basis weight of 120 g / m 2 Film PPS-1: Polyphenylene sulfide ("TORELINA" (registered trademark) A900 (manufactured by Toray Industries, Inc., melting point 278°C)) with a basis weight of 120 g / m 2 Film PPS-2: Polyphenylene sulfide ("TORELINA" (registered trademark) A670T05 (manufactured by Toray Industries, Inc., melting point 278°C)) with a basis weight of 120 g / m 2 Film PEKK1: Polyether ketone ketone ("KEPSTAN" (registered trademark) 6002 (manufactured by Arkema, melting point 300°C)) with a basis weight of 120 g / m 2 Film PEKK2: Polyether ketone ketone ("KEPSTAN" (registered trademark) 7002 (manufactured by Arkema, melting point 331°C)) with a basis weight of 120 g / m 2 Film PEEK: Polyether ether ketone (PEEK 450G (Victrex, melting point 343°C)) with a basis weight of 120 g / m 2 Film Semi-aromatic PA: Polyamide 6T (glass transition temperature 125°C) with a basis weight of 120 g / m 2 Film PEI: Polyetherimide (ULTEM® 1010 (SABIC, glass transition temperature 217°C)) with a basis weight of 120 g / m 2 Film

[0048] (1) Method for measuring the melting point and glass transition point of thermoplastic resins The melting points of thermoplastic resins were measured using a differential scanning calorimeter (DSC) in accordance with JIS K7121 (2012). When multiple melting points or glass transition points were observed in a mixture, the highest melting point or glass transition point was used as the melting point or glass transition point of the thermoplastic resin. (2) Viscoelasticity measurement method for thermoplastic resins The viscoelasticity of thermosetting resins was measured using a dynamic viscoelasticity analyzer, ARES-G2 (TA Instruments). The upper and lower measuring jigs were 40 mm in diameter, parallel plates. The resin was set so that the distance between the upper and lower jigs was 1 mm, and measurements were performed at a strain rate of 3.14 rad / s. For crystalline thermoplastic resins, the temperature was raised from their melting point to a temperature equal to 60°C above the melting point at a rate of 1.5°C / min, and the viscosity was measured at a temperature equal to 40°C above the melting point. For amorphous thermoplastic resins, the temperature was raised from their glass transition temperature to a temperature equal to 60°C above the glass transition temperature at a rate of 1.5°C / min, and the viscosity was measured at a temperature equal to 40°C above the glass transition temperature.

[0049] <Prepreg manufacturing method and evaluation method> The prepregs were produced by the following two methods. The components used in each example are as shown in Tables 2 and 3. [I] Reinforced fiber of component [A] (weight 193 g / m 2 ) is pulled out from the continuous reinforcing fiber sheet aligned in one direction, and while running in one direction, a sheet of 120 g / m2 of component [C] is 2The resin sheet was placed on the continuous reinforcing fiber sheet, heated with an IR heater to melt the component [C], and adhered to the entire surface of one side of the continuous reinforcing fiber sheet. Pressurization was performed with a nip roll whose surface temperature was kept below the melting point of the component [C], and the reinforcing fiber sheet impregnated with the component [C] was cooled to obtain an intermediate. The thermosetting resin for component [B] selected as shown in Tables 2 and 3 was applied using a knife coater to a resin basis weight of 100 g / m. 2 The thermosetting resin film was coated on release paper with the above composition to produce a thermosetting resin film. In Tables 2 and 3, cases where the thermosetting resin film on the release paper was coated without any visible fading were recorded as "no fading of resin film." Furthermore, cases where the thermosetting resin remained on the release paper when the release paper covering the side opposite the thermosetting resin-coated release paper was wound up were recorded as "resin removal" in Tables 2 and 3. The resin basis weight of the produced thermosetting resin film was measured at five points every 1 m, and the standard deviation was recorded as "unevenness in film basis weight" in Tables 2 and 3. Next, the thermosetting resin film was placed on the surface of the intermediate opposite the surface impregnated with component [C], and the intermediate was impregnated with the thermosetting resin while being heated and pressurized by a heat roll, to obtain prepreg [I]. [II] The thermosetting resin for component [B] selected as shown in Table 2 is applied using a knife coater to a resin coating weight of 50 g / m 2 The resin film was coated on a release paper with the above-mentioned composition, and the reinforcing fibers of the component [A] (weight per unit area: 193 g / m) were unidirectionally aligned. 2 The carbon fibers were impregnated with the thermosetting resin while being heated and pressurized using heat rolls to obtain prepreg [II].

[0050] <Laminate manufacturing method and mechanical property evaluation> (1) Measurement method for tensile shear bond strength The prepregs [I] and [II] prepared above were cut to a predetermined size to obtain two prepregs [I] and six prepregs [II]. The axial direction of the reinforcing fibers was defined as 0°, and the direction perpendicular to the axial direction was defined as 90°, so the [0° / 90°] 2s(The symbol s indicates mirror symmetry) to produce a preform. At this time, the two outermost layers on each side were laminated to form prepregs [I], and both surface layers of the preform were arranged to form thermoplastic resin layers containing the component [C]. This preform was set in a press mold, and, while maintaining this shape using jigs or spacers as necessary, a pressure of 0.6 MPa was applied in a press and heated at 180°C for 120 minutes to obtain a laminate. The resulting laminate was cut into two pieces, 250 mm wide and 92.5 mm long, with the 0° direction as the length direction of the test piece, and dried in a vacuum oven for 24 hours. The two panels were then stacked, measuring 25 mm wide and 12.5 mm long, with the 0° direction as the length direction. The stacked surfaces were welded together by applying a pressure of 3 MPa at a temperature 20°C higher than the melting point of the thermoplastic resin used in component [C] and holding for 1 minute to obtain an integrated molded product. Tabs were attached to the resulting integrated molded product in accordance with ISO 4587:1995 (JIS K6850(1994)), and the desired test specimens were then cut to a width of 25 mm. The resulting test pieces were dried in a vacuum oven for 24 hours, and the tensile shear bond strength was measured at ambient temperatures of 23°C and 80°C in accordance with ISO 4587:1995 (JIS K6850 (1994)). The results were evaluated as follows: The coefficient of variation was calculated by determining the standard deviation and average value from five measurements of the tensile shear bond strength, and then dividing the standard deviation by the average value. The results are shown in Tables 2 and 3. (a) Tensile shear bond strength at 23°C 28MPa or more:A 25MPa or more but less than 28MPa: B 20MPa or more but less than 25MPa: C Less than 20 MPa: D (fail) (b) Tensile shear bond strength at 80°C 16MPa or more:A 13MPa or more but less than 16MPa: B 10MPa or more but less than 13MPa: C Less than 10 MPa: D (fail)

[0051] (2) Interlaminar fracture toughness (G IIC ) measurement method The prepreg [I] prepared above was cut to a specified size and a total of 20 sheets were laminated so that the reinforcing fiber direction was the same. At this time, a release film for introducing preliminary cracks was sandwiched between the 10th and 11th central sheets to prepare a preform. This preform was set in a press mold, and if necessary, using jigs or spacers to maintain this shape, a pressure of 0.6 MPa was applied in a press, and the laminate was obtained by heating at 180°C for 120 minutes. From the obtained laminate, rectangular test pieces of 150 mm in length and 20 mm in width were cut out with the reinforcing fiber axis in the longitudinal direction of the test piece, and dried in a vacuum oven at 60°C for 24 hours. The obtained test pieces were measured for interlaminar fracture toughness (G IIC ) was evaluated.

[0052] <Measurement of mean roughness length RSm and mean roughness height Rc in prepregs and laminates> Using the prepreg [I] prepared above, a cross section cut perpendicular to the planar direction of the prepreg at a 45° angle in a planar view of the prepreg relative to any fiber direction of [A] that contacts both resin regions was photographed using an optical microscope at 1000x magnification. In any 500 μm square observation area in the obtained image, the roughness mean length RSm and roughness mean height Rc of the cross-sectional curve element obtained using the above-mentioned cross-sectional curve element measurement method 1, as defined in JIS B0601 (2001), were measured. In the obtained image, if a reinforcing fiber was present at the interface between the resin region containing [C] and the resin region containing [B], and the reinforcing fiber was in contact with both the resin region containing [C] and the resin region containing [B], it was considered to be in a state where "reinforcing fiber straddling the interface and in contact with both resin regions." In the case of a laminate, a laminate described in (1) "Method for measuring tensile shear bond strength" was used, and a 1000x magnification image was photographed using an optical microscope at the observation cross section cut perpendicular to the planar direction. The rest of the measurements were performed in the same manner as for the prepreg.

[0053] <Methods for producing laminates in Examples 1 to 14 and Comparative Examples 1 and 2> In Examples 1 to 14 and Comparative Examples 1 and 2, laminates and integrally molded articles were produced by the method described in (1) Method for measuring tensile shear bond strength.

[0054] <Methods for producing laminates in Example 15 and Comparative Examples 3 to 5> In Comparative Example 3, a film with a basis weight of 50 g / m was applied to both sides of a reinforcing fiber sheet arranged in a unidirectional plane. 2 A film of polyamide 6 ("Amilan" (registered trademark) CM1007 (manufactured by Toray Industries, Inc.)) was attached, and the sheet was heated and pressed at 250°C to a carbon fiber basis weight of 193 g / m. 2 The prepregs obtained were cut to a predetermined size and then split into [0° / 90°] pieces for evaluation of bonding strength and compression strength. 2s Alternatively, eight sheets were stacked in the same direction, and then a pressure of 3 MPa was applied using a press, and the laminate was heated at 250° C. for 10 minutes to obtain a laminate. The tensile shear bond strength of the obtained laminate was measured using the method described in the Examples. In Example 15, the prepreg [I] was cut to a predetermined size, and a total of 20 sheets were stacked so that the reinforcing fiber direction was the same. A release film for introducing a preliminary crack was sandwiched between the central 10th and 11th sheets to produce a preform. In Comparative Example 4, the prepreg [II] (not containing the component [C]) was cut to a predetermined size, laminated in the same manner as in Example 15, and a release film was sandwiched between the layers to obtain a preform. In Comparative Example 5, polyamide particles (SP-500, manufactured by Toray Industries, Inc.) were applied to one surface of a prepreg [II] (not containing the component [C]) cut to a predetermined size so that the particle amount per unit area of ​​the prepreg was 7 g / m. 2 After uniformly dispersing the mixture so that the thickness was as follows: 1500 μm, the mixture was laminated in the same manner as in Example 15, and a release film was sandwiched between the layers to obtain a preform. In both Example 15 and Comparative Examples 4 and 5, the obtained preforms were subjected to a pressure of 0.6 MPa in a press and heated at 180°C for 120 minutes to obtain laminates, and then the interlaminar fracture toughness (G IIC ) was evaluated.

[0055] [Table 1]

[0056] [Table 2]

[0057] [Table 3] [Explanation of symbols]

[0058] 1: Prepreg or laminate 2: Component [A] 3: Component [C] and Component [B] or Component [D] 4: Axial direction of any fiber bundle 5: Observation cross section 6: Component [A] 7: Resin region containing component [C] 8: Resin region containing component [B] or component [D] 9: Observation image 10: Boundary 11: Reference line 12: Orthobase line 13: Cross section curve

Claims

1. A prepreg comprising the following components [A], [B], and [C], wherein [B] comprises 10% by mass or more of a thermoplastic resin having an aromatic ring; a resin region containing [B] is present on one surface of the prepreg, and a resin region containing [C] is present on the other surface; [A] is present across the boundary between the resin region containing [B] and the resin region containing [C], and is in contact with both resin regions; [B] has a storage modulus at 90°C of 1.0 to 100 Pa, a minimum viscosity of 0.5 Pa s or more, and the temperature at which the minimum viscosity is reached is in a range of 120°C or higher during a temperature rise process at 1.5°C / min as measured with a rheometer; the thermoplastic resin having an aromatic ring is polyethersulfone or polyetherimide; and [C] is one or more selected from polyamide, polyarylene ether ketone, polyphenylene sulfide, polyethersulfone, and polyetherimide. [A] Reinforced fiber [B] Thermosetting resin [C] Thermoplastic resin

2. In a plan view of the prepreg, when a cross section perpendicular to a prepreg plane including the [A] is obtained from a direction at an angle of 45 degrees different from the fiber direction of any [A] that contacts both resin regions, the roughness average length RSm defined in JIS B0601 (2001) of a cross-sectional curve formed by an interface where both resin regions are in close contact in the cross section is 100 μm or less and a roughness average height Rc is 3.5 μm or more. The prepreg according to claim 1,

3. The prepreg according to claim 1 or 2, wherein the resin region containing [B] and the resin region containing [C] are adjacent to each other in layers, thereby forming the boundary surface.

4. A laminate comprising layers containing the following components [A], [C], and [D], wherein [D] contains 13 mass% or more of a thermoplastic resin having an aromatic ring, and [A] is present across the boundary between a resin region containing [C] and a resin region containing [D] and is in contact with both resin regions, and the laminate satisfies the following [1] to [3]: [A] Reinforced fiber [C] Thermoplastic resin [D] Thermosetting resin cured product [1] The thermoplastic resin having an aromatic ring is polyethersulfone or polyetherimide. [2] The weight average molecular weight of the thermoplastic resin having an aromatic ring is 10,000 g / mol or more and 40,000 g / mol or less. [3] [C] is one or more selected from polyamide, polyarylene ether ketone, polyphenylene sulfide, polyether sulfone, and polyether imide.

5. 5. The laminate according to claim 4, wherein, in a plan view of the laminate, when a cross section perpendicular to the plane of the laminate including any one of [A] in contact with both of the resin regions is obtained from a direction at an angle of 45 degrees different from the fiber direction of the any one of [A] in contact with both of the resin regions, the cross section curve formed by the boundary surface where both of the resin regions are in close contact in the cross section has a roughness average length RSm defined in JIS B0601 (2001) of 100 μm or less and a roughness average height Rc of 3.5 μm or more.

6. The laminate according to claim 4 or 5, wherein the resin region containing [C] and the resin region containing [D] are adjacent to each other in a layered form, thereby forming the boundary surface.

7. The laminate according to any one of claims 4 to 6, wherein a resin region containing the component [C] is present on the surface.

8. The laminate according to any one of claims 4 to 7, wherein [D], in an uncured state before curing, has a storage modulus at 90°C of 1.0 to 100 Pa, a minimum viscosity of 0.5 Pa s or more, and a temperature at which the minimum viscosity is reached is in a range of 120°C or more, during a temperature increase process at 1.5°C / min using a rheometer.

9. [A] is a material having a surface free energy measured by the Wilhelmy method of 10 to 50 mJ / m ２ 9. The prepreg according to claim 1, or the laminate according to claim 4, wherein the reinforcing fibers are:

10. A laminate, at least some of whose layers are constituted by a cured product of the prepreg according to any one of claims 1 to 3.

11. An integrally molded article obtained by joining another member to the surface where [C] is present, thereby integrating the laminate according to claim 7 with the other member.

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