Prepreg and method for producing the same, fiber-reinforced composite

Abstract

The application relates to the technical field of fiber reinforced composites, in particular to a prepreg, a preparation method thereof and a fiber reinforced composite. The prepreg comprises a reinforcing material and a resin composition attached to the reinforcing material; the reinforcing material is carbon fiber; the resin composition comprises the following components in parts by weight: 100 parts of an epoxy resin, 0.1-10 parts of an epoxy-containing diluent, 1-12.5 parts of a tackifier, 4-10 parts of a curing agent, and 1-5 parts of an accelerator; the epoxy resin comprises one or more of bisphenol A type epoxy resin, multifunctional epoxy resin and phenolic epoxy resin, and the epoxy equivalent weight of the bisphenol A type epoxy resin and the phenolic epoxy resin is independently 155 g / eq-220 g / eq. The prepreg has good quality consistency, and can effectively improve the mechanical properties of the fiber reinforced composite.

Description

Technical Field

[0001] This application relates to the field of fiber-reinforced composite materials technology, specifically to prepregs and their preparation methods, and fiber-reinforced composite materials. Background Technology

[0002] Prepreg is a semi-finished material made by impregnating reinforcing fibers and matrix resin. It is a key intermediate product in the preparation of fiber-reinforced composite materials.

[0003] Currently, the main methods for preparing prepreg resin compositions include solvent-based and powder-based methods. Solvent-based resin compositions have the disadvantage that the solvent is difficult to completely evaporate, and the residual solvent can cause performance fluctuations in the prepreg during storage and curing, affecting the stability of the final composite material. Powder-based resin compositions involve attaching resin powder to the surface of reinforcing fibers, but the resin particles are difficult to distribute uniformly, and local accumulation or gaps are prone to occur, resulting in poor consistency of prepreg quality and ultimately affecting the mechanical properties of fiber-reinforced composites. Summary of the Invention

[0004] Based on this, this application provides a prepreg, a method for preparing the same, and a fiber-reinforced composite material. The prepreg of this application avoids solvent residue, has a uniform resin composition distribution, and exhibits good prepreg quality consistency, effectively improving the mechanical properties of the fiber-reinforced composite material.

[0005] A first aspect of this application provides a prepreg comprising a reinforcing material and a resin composition attached to the reinforcing material;

[0006] The reinforcing material is carbon fiber; the resin composition comprises the following components in parts by weight: 100 parts epoxy resin, 0.5 to 10 parts epoxy-containing diluent, 1 to 12.5 parts tackifier, 4 to 10 parts curing agent, and 1 to 5 parts accelerator.

[0007] Optionally, the epoxy resin includes one or more of bisphenol A type epoxy resin, multifunctional epoxy resin, and phenolic epoxy resin, wherein the epoxy equivalent of the bisphenol A type epoxy resin and the phenolic epoxy resin are each independently 155 g / eq to 220 g / eq; the multifunctional epoxy resin includes , , and One or more of them.

[0008] In some embodiments, the carbon fiber is a polyacrylonitrile-based carbon fiber.

[0009] In some embodiments, the epoxy-containing diluent includes and One or more of the following: R1 is a C3-C6 alkyl group; n is any integer from 3 to 6.

[0010] In some embodiments, the tackifier includes one or more of phenoxy resin, solid epoxy resin, and acrylate block copolymer.

[0011] In some embodiments, the curing agent includes one or more of dicyandiamide curing agents and 4,4'-diaminodiphenyl sulfone.

[0012] In some embodiments, the accelerator includes one or more of organic urea and imidazole accelerators.

[0013] In some embodiments, the epoxy resin comprises the bisphenol A type epoxy resin and the multifunctional epoxy resin in a mass ratio of 1:(8~9).

[0014] In some embodiments, the epoxy resin comprises the multifunctional epoxy resin and the phenolic epoxy resin in a mass ratio of (5~6):1.

[0015] In some embodiments, the prepreg contains 60% to 77% by mass of the reinforcing material.

[0016] In some embodiments, the resin composition in the prepreg has a mass fraction of 23% to 40%.

[0017] A second aspect of this application provides a method for preparing the prepreg described in the first aspect of this application, comprising the following steps:

[0018] The resin composition is prepared according to the formulation, and the resin composition is liquefied to prepare an impregnation solution;

[0019] The reinforcing material is impregnated in the impregnation solution, and after cooling, the prepreg is prepared.

[0020] In some of these embodiments, the liquefaction temperature is 65°C to 85°C.

[0021] A third aspect of this application provides a fiber-reinforced composite material formed by curing a prepreg as described in any of the first aspects of this application.

[0022] In some embodiments, the glass transition temperature of the fiber-reinforced composite material is 115°C to 250°C.

[0023] In some embodiments, the tensile strength of the fiber-reinforced composite material is 2200 MPa to 3200 MPa.

[0024] In some embodiments, the 0° tensile modulus of the fiber-reinforced composite material is 150 GPa to 175 GPa.

[0025] The beneficial effects of the prepreg provided in this application include at least the following:

[0026] In this application, carbon fiber, which has high strength properties, is used as the reinforcing material, which is beneficial to improving the mechanical properties of the prepreg. Furthermore, the reinforcing material is supplemented with a resin composition of specific weight parts and specific components, which can avoid solvent residue through the synergistic effect of the components and ensure uniform distribution of the resin composition.

[0027] Specifically, using a specific epoxy equivalent and a specific type of epoxy resin as the matrix ensures the strength and toughness of the resin composition. Furthermore, the cross-linking effect of the epoxy resin matrix further increases the glass transition temperature. The good compatibility between the epoxy-containing diluent and the epoxy resin, along with the interfacial bonding between the tackifier and the carbon fiber, allows the resin composition to adhere without solvents, effectively avoiding solvent residue and reducing the risk of interfacial failure. Moreover, the synergistic effect of the curing agent and accelerator prevents epoxy resin degradation caused by high temperatures while ensuring uniform curing reaction, which also helps avoid uneven distribution of the resin composition. Furthermore, based on the synergistic effect of enhanced interfacial bonding and uniform resin distribution, the prepreg of this application can also achieve an improvement in monofilament strength conversion rate.

[0028] In summary, the prepreg of this application can avoid solvent residue, and the resin composition is uniformly distributed and the prepreg quality is consistent, which can effectively improve the mechanical properties of fiber-reinforced composite materials. Attached Figure Description

[0029] Figure 1 A process flow diagram illustrating a method for preparing a prepreg provided as an example in this application. Detailed Implementation

[0030] The prepreg and its preparation method, as well as the fiber-reinforced composite material of this application, are further described in detail below with reference to specific embodiments. This application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0031] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0032] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. Unless otherwise stated or in case of conflict, the terms or phrases used herein have the following meanings:

[0034] In this application, the terms "multiple", "various", "multiple times", "multi-dimensional", etc., unless otherwise specified, refer to a quantity greater than or equal to 2. For example, "one or more" means one or more or more.

[0035] In this application, the terms "first aspect," "second aspect," "third aspect," and "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," and "fourth," etc., serve only a non-exhaustive enumeration purpose and should be understood not to constitute a closed limitation on quantity.

[0036] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0037] In this application, the terms "combinations thereof", "any combination thereof", and "any combination thereof" include all suitable combinations of any two or more of the listed items.

[0038] In this application, the term "suitable" as used in phrases such as "suitable combination," "suitable method," and "any suitable method" refers to the ability to implement the technical solution of this application, solve the technical problem of this application, and achieve the expected technical effect of this application.

[0039] In this application, terms such as "preferred," "better," "more suitable," and "ideal" are used only to describe implementation methods or embodiments with better effects, and should be understood not to constitute a limitation on the scope of protection of this application.

[0040] In this application, terms such as "further," "even further," and "particularly" are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0041] In this application, the terms "optionally," "optionally," and "optional" refer to options that are optional, meaning they can be selected from either "with" or "without." If multiple "optional" options appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "optional" option is independent.

[0042] In this application, numerical intervals (i.e., numerical ranges) are involved. Unless otherwise specified, the selected numerical distributions within the aforementioned numerical intervals are considered continuous and include the two endpoints (i.e., the minimum and maximum values) of the numerical range, as well as every value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints. In this document, this is equivalent to directly listing every integer. For example, if t is an integer selected from 1 to 10, it means that t is any integer selected from the group of integers consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10. Furthermore, when multiple ranges are provided to describe features or characteristics, these ranges can be merged. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all subranges to which they are included.

[0043] Unless otherwise specified, the temperature parameters in this application are permitted to be either constant-temperature treatment or variations within a certain temperature range. It should be understood that the constant-temperature treatment allows temperature fluctuations within the precision range of the instrument control, such as ±5℃, ±4℃, ±3℃, ±2℃, or ±1℃.

[0044] In this application, percentage content refers to mass percentage for solid-liquid mixtures and solid-phase mixtures, and volume percentage for liquid-phase mixtures, unless otherwise specified.

[0045] In this application, unless otherwise specified, percentage concentrations refer to final concentrations. The final concentration refers to the percentage of the added component in the system after its addition.

[0046] A first aspect of this application provides a prepreg comprising a reinforcing material and a resin composition attached to the reinforcing material;

[0047] The reinforcing material is carbon fiber; the resin composition comprises the following components in parts by weight: 100 parts epoxy resin, 0.5 to 10 parts epoxy-containing diluent, 1 to 12.5 parts tackifier, 4 to 10 parts curing agent, and 1 to 5 parts accelerator.

[0048] For example, the number of parts by weight of the epoxy-based diluent includes, but is not limited to, 0.5 parts, 1 part, 2 parts, 3 parts, 4 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, 8 parts, or 10 parts.

[0049] Optionally, the epoxy resin includes one or more of bisphenol A type epoxy resin, multifunctional epoxy resin, and phenolic epoxy resin. The epoxy equivalent of both the bisphenol A type epoxy resin and the phenolic epoxy resin is independently 155 g / eq to 220 g / eq. The multifunctional epoxy resin includes... , , and One or more of them.

[0050] In this application, carbon fiber, which has high strength properties, is used as the reinforcing material, which is beneficial to improving the mechanical properties of the prepreg. Furthermore, the reinforcing material is supplemented with a resin composition of specific weight parts and specific components, which can avoid solvent residue through the synergistic effect of the components and ensure uniform distribution of the resin composition.

[0051] Specifically, using a specific epoxy equivalent and a specific type of epoxy resin as the matrix ensures the strength and toughness of the resin composition, and the cross-linking effect of the epoxy resin matrix further increases the glass transition temperature. The good compatibility between the epoxy-containing diluent and the epoxy resin, as well as the interfacial bonding effect between the tackifier and the carbon fiber, allows the resin composition to adhere without solvents, effectively avoiding solvent residue and reducing the risk of interfacial failure; it also promotes non-adhesion between monofilaments, eliminating the need for additional release films to prevent adhesion. Simultaneously, the combination of epoxy resin and epoxy resin diluent can adjust the viscosity and flowability of the resin composition, making it easy to control the resin content and width in the prepreg, thus ensuring consistent prepreg quality and contributing to its room temperature storage stability. Furthermore, the synergistic effect of the curing agent and accelerator prevents epoxy resin degradation caused by high temperatures while ensuring uniform curing reaction, which also helps avoid uneven resin composition distribution. Furthermore, based on the synergistic effect of enhanced interfacial bonding and uniform resin distribution, the prepreg of this application can also achieve an improvement in monofilament strength conversion rate.

[0052] In some examples, the carbon fiber is polyacrylonitrile-based carbon fiber. For example, polyacrylonitrile-based carbon fiber includes, but is not limited to, T700 or T800. Polyacrylonitrile-based carbon fiber (such as T700 and T800) has high strength, high modulus, low density, and excellent corrosion resistance, which can improve the mechanical properties of prepregs; at the same time, it has good compatibility with resin compositions, enabling an improvement in monofilament strength conversion rate.

[0053] Epoxy resin, as the matrix of the resin composition, combined with reinforcing materials, imparts suitable viscosity, curing properties, mechanical properties, and storage stability to the prepreg, providing a foundation for subsequent curing and molding. Optionally, the epoxy resin includes one or more of bisphenol A type epoxy resin, multifunctional epoxy resin, and phenolic epoxy resin. The epoxy equivalent of both the bisphenol A type epoxy resin and the phenolic epoxy resin is independently 155 g / eq to 220 g / eq. The functionality of the multifunctional epoxy resin is 3 to 4. For example, the epoxy equivalent of the bisphenol A type epoxy resin and the phenolic epoxy resin includes, but is not limited to, 155 g / eq, 160 g / eq, 170 g / eq, 180 g / eq, 190 g / eq, 195 g / eq, 200 g / eq, 210 g / eq, or 220 g / eq, or any two of the above values ​​as endpoints.

[0054] As a further example, the epoxy equivalent of bisphenol A type epoxy resin is 180 g / eq to 190 g / eq, and the type of bisphenol A type epoxy resin includes, but is not limited to, NPEL-128E.

[0055] As further examples, the epoxy equivalent of the phenolic epoxy resin is 185 g / eq to 210 g / eq, and the type of the phenolic epoxy resin is NPPN-438. The epoxy equivalent of the phenolic epoxy resin is 155 g / eq to 175 g / eq, and the type of the phenolic epoxy resin is NPPN-442.

[0056] As a further example, multifunctional epoxy resins include , , and One or more of the following. The corresponding multifunctional epoxy resin models include, but are not limited to, AG-80, AFG-90, or TDE-85.

[0057] Further, the epoxy resin comprises the bisphenol A type epoxy resin and the multifunctional epoxy resin in a mass ratio of (2.5~3.5):1. For example, the mass ratio of the bisphenol A type epoxy resin and the multifunctional epoxy resin includes, but is not limited to, 2.5:1, 2.8:1, 2.9:1, 3:1, 3.1:1, 3.2:1, 3.3:1, or 3.5:1, or any two of the above values ​​as endpoints.

[0058] In some examples, the epoxy resin comprises the multifunctional epoxy resin and the phenolic epoxy resin in a mass ratio of (5~6):1. For example, the mass ratio of the multifunctional epoxy resin and the phenolic epoxy resin includes, but is not limited to, 5:1, 5.1:1, 5.3:1, 5.5:1, 5.8:1, or 6:1, or any two of the above values ​​as endpoints.

[0059] This application finds that the above-mentioned epoxy resin compound can reduce internal stress by regulating the balance of strength and toughness of the cross-linked structure, while improving the interfacial bonding force between the resin and carbon fiber, ultimately further improving the mechanical properties of the prepreg.

[0060] Understandably, the weight percentage of the epoxy-containing diluent can be selected from any value between 3 and 8 parts. For example, the weight percentage of the epoxy-containing diluent includes, but is not limited to, 3, 4, 5, 6, 7, or 8 parts, or any two of the above points as endpoints.

[0061] In some of these examples, the epoxy-containing diluent includes and One or more of the following: R1 is a C3-C6 alkyl group; n is any integer from 3 to 6.

[0062] In this application, "alkyl" refers to a saturated hydrocarbon group containing a primary (or normal) carbon atom, or a secondary carbon atom, or a tertiary carbon atom, or a quaternary carbon atom, or a combination thereof. Phrases containing this term, such as "C3-C6 alkyl," refer to an alkyl group containing 3 to 6 carbon atoms, and each occurrence can independently be C3 alkyl, C4 alkyl, C5 alkyl, or C6 alkyl. Suitable examples include, but are not limited to, 1-propyl (n-propyl, n-Pr, n-propyl, -CH2CH2CH3), 2-propyl (i-Pr, i-propyl, -CH(CH3)2), 1-butyl (n-butyl, n-Bu, n-butyl, -CH2CH2CH2CH3), 2-methyl-1-propyl (i-Bu, i-butyl, -CH2CH(CH3)2), and 2-butyl (s-Bu, s-butyl, -CH(CH3)CH2CH3).

[0063] As a further example, R1 is -CH2CH2CH2CH3. The epoxy-containing diluent is butyl glycidyl ether. .

[0064] As a further example, n is 3, 4, 5, or 6. The epoxy-containing diluent is hexanediol diglycidyl ether. .

[0065] Understandably, the weight percentage of the tackifier can be selected from any value between 1 part and 12.5 parts. For example, the weight percentage of the tackifier includes, but is not limited to, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, or 12.5 parts, or any two of the above points as endpoints.

[0066] In some of these examples, the tackifier comprises one or more of phenoxy resins, solid epoxy resins, and acrylate block copolymers.

[0067] Further, the hydroxyl equivalent of the phenoxy resin is 260 g / eq to 290 g / eq. The hydroxyl equivalent of the phenoxy resin includes, but is not limited to, 260 g / eq, 270 g / eq, 275 g / eq, 277 g / eq, 280 g / eq, 282 g / eq, 285 g / eq, or 290 g / eq, or any two of the above values ​​as endpoints. As a further example, the hydroxyl equivalent of the phenoxy resin is 278 g / eq to 282 g / eq, and its type includes, but is not limited to, PKHH. The hydroxyl equivalent of the phenoxy resin is 275 g / eq to 277 g / eq, and its type includes, but is not limited to, PKHB.

[0068] The solid epoxy resin is a bisphenol A type-epoxypropyl ether resin. The types of solid epoxy resins include, but are not limited to, NPES-909. The types of acrylate block copolymers include, but are not limited to, M22N.

[0069] The weight percentage of the curing agent can be selected from any value between 4 and 10 parts. For example, the weight percentage of the curing agent includes, but is not limited to, 4, 5, 6, 7, 8, 9, or 10 parts, or any two of the above points as endpoints.

[0070] In some of these examples, the curing agent includes one or more of dicyandiamide curing agents and 4,4'-diaminodiphenyl sulfone.

[0071] Furthermore, the dicyandiamide curing agent is an epoxy-containing dicyandiamide curing agent. Types of dicyandiamide curing agents include, but are not limited to, Dyhard 100SF.

[0072] Understandably, the weight percentage of the accelerator can be selected from any value between 1 and 5 parts. For example, the weight percentage of the accelerator includes, but is not limited to, 1 part, 2 parts, 3 parts, 4 parts, or 5 parts, or any two of the above points as endpoints.

[0073] In some of these examples, the promoter includes one or more of organic urea and imidazole promoters.

[0074] Organic urea types include, but are not limited to, Dyhard UR200. For example, the structure of an imidazole accelerator is... Furthermore, the types of imidazole accelerators include, but are not limited to, Shikoku Chemical's imidazole 2MA-OK.

[0075] Preferably, the epoxy resin comprises bisphenol A type epoxy resin and multifunctional epoxy resin in a mass ratio of (2.5~3.5):(6.5~7.5). Preferably, the tackifier is a solid epoxy resin. Preferably, the curing agent is a dicyandiamide curing agent. Preferably, the accelerator is an organic urea.

[0076] In some examples, the prepreg contains 60% to 77% by mass of the reinforcing material. For example, the mass fraction of the reinforcing fiber includes, but is not limited to, 60%, 63%, 65%, 68%, 70%, 72%, 73%, 75%, or 77%, or any two of the above values ​​as endpoints.

[0077] In some examples, the prepreg contains a resin composition with a mass fraction of 23% to 40%. For example, the mass fraction of the resin composition includes, but is not limited to, 23%, 25%, 27%, 29%, 32%, 35%, 38%, or 40%, or any two of the above values ​​as endpoints.

[0078] The prepregs within the above-mentioned content can ensure the high strength and rigidity of the prepregs by reinforcing the fibers, and can also achieve full impregnation and bonding of the fibers by the resin composition, thus taking into account both mechanical properties and molding processability.

[0079] See Figure 1 A second aspect of this application provides a method for preparing the prepreg described in the first aspect of this application, comprising the following steps:

[0080] S10: Prepare the resin composition according to the formulation, liquefy the resin composition, and prepare an impregnation solution.

[0081] S20: The reinforcing material is impregnated in the impregnation solution, and after cooling, the prepreg is prepared.

[0082] Understandably, the components, types, weight fractions, etc. of the resin composition in step S10 are similar to those in the first aspect of this application, so they will not be repeated here.

[0083] In some examples, the liquefaction temperature in step S10 is 65°C to 85°C. For example, the liquefaction temperature includes, but is not limited to, 65°C, 68°C, 70°C, 72°C, 75°C, 78°C, 80°C, 82°C, or 85°C, or any two of the above values ​​as endpoints. The apparatus for liquefying the resin composition in step S10 includes, but is not limited to, an impregnation tank. The above-mentioned liquefaction temperature is adapted to the resin composition of the specific components of this application, ensuring uniform liquefaction and suitable viscosity of the resin composition, and avoiding premature reaction or degradation of components due to slightly higher temperatures, or incomplete liquefaction and higher viscosity due to slightly lower temperatures, thereby ensuring the stability of the impregnation solution and the subsequent uniform impregnation effect on the reinforcing material.

[0084] Further, in step S20: the reinforcing material is impregnated in the impregnation liquid and cooled to prepare the prepreg, the reinforcing fiber can be drawn to impregnate in the impregnation liquid by an unwinding and winding device; then the impregnated reinforcing fiber is cooled by a cooling roller and wound up by a winding device to obtain the prepreg.

[0085] A third aspect of this application provides a fiber-reinforced composite material formed by curing a prepreg as described in any of the first aspects of this application.

[0086] Furthermore, the curing temperature is 100℃~200℃. For example, the curing temperature includes, but is not limited to, 100℃, 110℃, 130℃, 150℃, 170℃, 190℃, or 200℃. This curing temperature ensures the resin composition is fully cross-linked and cured, avoiding incomplete curing and insufficient mechanical properties due to excessively low temperatures, while preventing material degradation or excessive internal stress due to excessively high temperatures. Simultaneously, it matches the reactivity of the accelerator and curing agent, achieving rapid curing while ensuring a uniform structure, balanced toughness and strength of the cured product, ultimately improving the overall performance of the composite material.

[0087] In some examples, the glass transition temperature of the fiber-reinforced composite material is 115°C to 250°C. For example, the glass transition temperature of the fiber-reinforced composite material includes, but is not limited to, 115°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 220°C, 240°C, or 250°C, or any two of the above values ​​as endpoints.

[0088] In some examples, the tensile strength of the fiber-reinforced composite material is 2200 MPa to 3200 MPa. For example, the tensile strength includes, but is not limited to, 2200 MPa, 2400 MPa, 2600 MPa, 2700 MPa, 2800 MPa, 2900 MPa, 3000 MPa, 3100 MPa, or 3200 MPa, or any two of the above values ​​as endpoints.

[0089] In some examples, the tensile strength of the single filament of the fiber-reinforced composite material is 5400 MPa to 5600 MPa. For example, the tensile strength of the single filament includes, but is not limited to, 5400 MPa, 5450 MPa, 5500 MPa, 5550 MPa, or 5600 MPa, or any two of the above values ​​as endpoints.

[0090] In this application, "monofilament tensile strength" refers to the maximum pressure that a single carbon fiber can withstand when stretched to the point of breakage. "Tension strength" takes 24K carbon fiber as an example, referring to the maximum tensile force that a 24K carbon fiber bundle composed of multiple carbon fiber monofilaments can withstand when stretched to the point of breakage. Its value comprehensively reflects the overall ability of the fiber bundle to resist tensile failure, and together with the monofilament tensile strength, it reflects the mechanical performance level of carbon fiber.

[0091] In some examples, the 0° tensile strength of the fiber-reinforced composite material is 2200 MPa to 3200 MPa. For example, the 0° tensile strength includes, but is not limited to, 2200 MPa, 2400 MPa, 2600 MPa, 2700 MPa, 2800 MPa, 2900 MPa, 3000 MPa, 3100 MPa, or 3200 MPa, or any two of the above values ​​as endpoints.

[0092] In this application, "0° tensile strength" refers to the maximum stress that a fiber-reinforced composite material can withstand until it breaks when subjected to a tensile force parallel to the fiber lay-up direction (i.e., the fiber axis).

[0093] In some examples, the 0° tensile modulus of the fiber-reinforced composite material is 150 GPa to 175 GPa. For example, the 0° tensile modulus includes, but is not limited to, 150 GPa, 155 GPa, 160 GPa, 165 GPa, 170 GPa, or 175 GPa, or any two of the above values ​​as endpoints.

[0094] In this application, "0° tensile modulus" refers to the ratio of stress to strain in the elastic deformation stage of a fiber-reinforced composite material when subjected to a tensile force parallel to the fiber layup direction (fiber axis). It is used to characterize the material's ability to resist elastic deformation in this direction; a larger value indicates greater rigidity of the material in the main fiber direction.

[0095] The above examples demonstrate that the fiber-reinforced composite material of this application has excellent tensile mechanical properties, suitable high temperature resistance and rigidity, and can meet the structural application requirements in high-strength and medium-high temperature environments.

[0096] The following detailed embodiments illustrate this application in more detail. It should also be understood that the following embodiments are for further explanation only and should not be construed as limiting the scope of protection of this application. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of this application fall within the scope of protection of this application. The specific process parameters, etc., in the following embodiments are merely examples within a suitable range; that is, those skilled in the art can make appropriate selections within the range based on the description herein, and are not necessarily limited to the specific values ​​in the embodiments below.

[0097] Example 1

[0098] The prepreg comprises reinforcing fibers (T700 series polyacrylonitrile-based carbon fiber) and an epoxy resin composition. The epoxy resin composition includes epoxy resin, an epoxy-containing diluent, a tackifier, a curing agent, and an accelerator in a mass ratio of 100:3:5:6:3. The epoxy resin is bisphenol A type epoxy resin (purchased from Nan Ya Electronics NPEL-128E, epoxy equivalent 180g / eq~190g / eq). The epoxy-containing diluent is butyl glycidyl ether (BGE). The tackifier is phenoxy resin (hydroxyl equivalent 278g / eq~282g / eq, model PKHH). The curing agent is dicyandiamide curing agent (purchased from Dyhard 100SF, Germany). The accelerator is organic urea (purchased from Dyhard UR200, Germany).

[0099] The preparation method includes: heating the above resin composition to 80°C to liquefy it, impregnating it with reinforcing fibers, shaping the impregnated reinforcing fibers by cooling rollers, and winding them into prepreg.

[0100] Testing of the prepreg revealed that the resin composition comprised 23%–33% by mass, the reinforcing fiber comprised 67%–77% by mass, and the fiber width was 6 nm. This indicates that the prepreg prepared in Example 1 exhibits uniform resin distribution and minimal variation in resin content, which is beneficial for ensuring consistent prepreg quality.

[0101] The prepreg was cured at 100℃~120℃ for 1h~2h to obtain fiber-reinforced composite materials. Differential scanning calorimetry (DSC) analysis showed that the glass transition temperature (Tg) of the fiber-reinforced composite materials was greater than 115℃.

[0102] For example, taking 24K carbon fiber as an example, when the resin composition content is 27%, the tensile strength of a single filament is 5553 MPa, the strength conversion rate of a single filament is 97.6%, the tensile strength at 0° is 2872 MPa, and the tensile modulus at 0° is 154 GPa.

[0103] Example 2

[0104] The prepreg comprises reinforcing fibers (T700 series polyacrylonitrile-based carbon fibers) and an epoxy resin composition. The epoxy resin composition includes epoxy resin, an epoxy-containing diluent, a tackifier, a curing agent, and an accelerator in a mass ratio of 100:8:5:8:2. The epoxy resin is a 30:70 mass ratio bisphenol A type epoxy resin (purchased from Nan Ya Electronics NPEL-128E, epoxy equivalent of 180g / eq~190g / eq) and a multifunctional epoxy resin (…). (Model: AG-80). The epoxy diluent is butyl glycidyl ether (BGE). The tackifier is solid epoxy resin (Nanya NPES-909). The curing agent is dicyandiamide curing agent (purchased from Dyhard 100SF, Germany). The accelerator is organic urea (purchased from Dyhard UR200, Germany).

[0105] The preparation method includes: heating the above resin composition to 70°C to liquefy it, impregnating it with reinforcing fibers, shaping the impregnated reinforcing fibers by cooling rollers, and winding them into prepreg.

[0106] The prepreg was cured at 160℃~180℃ for 3h~6h to obtain fiber-reinforced composite materials. Differential scanning calorimetry (DSC) tests showed that the glass transition temperature (Tg) of the fiber-reinforced composite materials was greater than 180℃.

[0107] As a further example, the above prepreg was cured at 160°C for 2 hours, and then cured at 180°C for 2 hours to obtain a fiber-reinforced composite material. Differential scanning calorimetry (DSC) showed that the glass transition temperature (Tg) of the fiber-reinforced composite material was 184.76°C. For example, using 24K carbon fiber with a resin composition content of 27%, the monofilament tensile strength was 5567 MPa, the monofilament strength conversion rate was 97.7%, the 0° tensile strength was 3045 MPa, and the 0° tensile modulus was 158 GPa.

[0108] Example 3

[0109] The prepreg comprises reinforcing fibers (T700 series polyacrylonitrile-based carbon fiber) and an epoxy resin composition. The epoxy resin composition includes epoxy resin, an epoxy-containing diluent, a tackifier, a curing agent, and an accelerator in a mass ratio of 100:1:3:10:2. The epoxy resin is a multifunctional epoxy resin in a mass ratio of 65:25:15. Model AG-80), multifunctional epoxy resin ( The product consists of AG-90 (epoxy equivalent 155g / eq~175g / eq, model NPPN-442) and phenolic epoxy resin. The epoxy-containing diluent is butyl glycidyl ether (BGE). The tackifier is an acrylate block copolymer (Arkema M22N). The curing agent is 4,4'-diaminodiphenyl sulfone (DDS). The accelerator is an imidazole accelerator (Shikoku Kasei imidazole 2MA-OK).

[0110] The preparation method includes: heating the above resin composition to 70°C to liquefy it, impregnating it with reinforcing fibers, shaping the impregnated reinforcing fibers by cooling rollers, and winding them into prepreg.

[0111] The prepreg was cured at 150℃ for 2 hours, and then cured at 200℃ for 2 to 4 hours to obtain the fiber-reinforced composite material. Differential scanning calorimetry (DSC) analysis showed that the glass transition temperature (Tg) of the fiber-reinforced composite material was greater than 200℃.

[0112] As a further example, the above prepreg was cured at 150°C for 2 hours and then cured at 200°C for 4 hours to obtain a fiber-reinforced composite material. At this point, taking 24K carbon fiber as an example, with a resin composition content of 27%, the monofilament tensile strength is 5253 MPa, the monofilament strength conversion rate is 92.19%, the 0° tensile strength is 2704 MPa, and the 0° tensile modulus is 162.3 GPa.

[0113] Example 4

[0114] Example 4 is basically the same as Example 2, the main difference being that the epoxy resin in Example 4 is a multifunctional epoxy resin with a mass ratio of 60:30:10 ( Model AG-80), multifunctional epoxy resin ( (model AG-90 isomer) and multifunctional epoxy resin ( Model TDE-85).

[0115] Testing of the prepreg revealed that the resin composition in the prepreg contained 23% to 33% by mass, the reinforcing fiber contained 67% to 77% by mass, and the fiber width of the prepreg was 6 nm.

[0116] The prepreg was cured at 150°C for 2 hours, and then cured at 200°C for 2 to 4 hours to obtain a fiber-reinforced composite material. Taking 24K carbon fiber as an example, when the resin composition content is 27%, the single filament tensile strength is 4969 MPa, the single filament strength conversion rate is 87.2%, the 0° tensile strength is 2604 MPa, and the 0° tensile modulus is 158 GPa.

[0117] Example 5

[0118] Example 5 is basically the same as Example 2, the main difference being that the tackifier in Example 5 is phenoxy resin (hydroxyl equivalent of 278g / eq~282g / eq, model PKHH).

[0119] After curing the above prepreg at 160℃~180℃ for 2h~4h, fiber-reinforced composite material is obtained. For example, taking 24K carbon fiber with medium composite as an example, when the resin composition content is 27%, the single filament tensile strength is 5487MPa, the single filament strength conversion rate is 96.3%, the 0° tensile strength is 3014MPa, and the 0° tensile modulus is 171GPa.

[0120] Example 6

[0121] Example 6 is basically the same as Example 2, the main difference being that the curing agent in Example 6 is 4,4'-diaminodiphenyl sulfone (DDS).

[0122] After curing the above prepreg at 100℃~120℃ for 1h~2h, fiber-reinforced composite material is obtained. For example, taking 24K carbon fiber with medium composite as an example, when the resin composition content is 27%, the single filament tensile strength is 5106MPa, the single filament strength conversion rate is 89.6%, the 0° tensile strength is 2613MPa, and the 0° tensile modulus is 157GPa.

[0123] Example 7

[0124] Example 7 is basically the same as Example 2, the main difference being that the accelerator in Example 7 is an imidazole accelerator (Shikoku Kasei imidazole 2MA-OK).

[0125] After curing the above prepreg at 100℃~120℃ for 1h~2h, fiber-reinforced composite material is obtained. For example, taking 24K carbon fiber with medium composite as an example, when the resin composition content is 27%, the tensile strength of a single filament is 4904MPa, the tensile strength at 0° is 2215MPa, and the tensile modulus at 0° is 150GPa.

[0126] Example 8

[0127] Example 8 is basically the same as Example 2, the main difference being that the content of the resin composition is different in Example 8.

[0128] Testing of the prepreg revealed that the resin composition in the prepreg comprised 23% by mass.

[0129] After curing the above prepreg at 100℃~120℃ for 1h~2h, fiber-reinforced composite material is obtained. For example, taking 24K carbon fiber with medium composite as an example, when the resin composition content is 23%, the single filament tensile strength is 5525MPa, the single filament strength conversion rate is 96.96%, the 0° tensile strength is 3150MPa, and the 0° tensile modulus is 159GPa.

[0130] Example 9

[0131] Example 9 is basically the same as Example 2, the main difference being that the carbon fiber manufacturer is different in Example 9.

[0132] After curing the above prepreg at 100℃~120℃ for 1h~2h, fiber-reinforced composite material is obtained. For example, taking Hyosung 24K carbon fiber as an example, when the resin composition content is 23%, the single filament tensile strength is 4290MPa, the single filament strength conversion rate is 74.12%, the 0° tensile strength is 2726MPa, and the 0° tensile modulus is 155GPa.

[0133] Comparative Example 1

[0134] Comparative Example 1 is basically the same as Example 1, except that the reinforcing material of Comparative Example 1 is glass fiber.

[0135] Testing of the prepregs revealed that the mass fraction of the resin composition ranged from 18% to 40%. This indicates that the resin distribution in the prepreg prepared in Comparative Example 1 was uneven, with significant variations in resin content, which is detrimental to ensuring the consistency of the prepreg's quality.

[0136] After curing the above prepreg at 100℃~120℃ for 1h~2h, fiber-reinforced composite material is obtained. For example, taking 24K carbon fiber with medium composite as an example, when the resin composition content is 35%, the tensile strength of a single filament is 2512MPa, the tensile strength at 0° is 1267MPa, and the tensile modulus at 0° is 50.65GPa.

[0137] As can be seen from the embodiments and comparative examples, embodiments 1 to 9 of this application have superior mechanical properties compared to comparative example 1.

[0138] Example 2 and Example 4 are basically the same, the main difference being that the types of epoxy resins used are different. From the perspective of technical effect, the preferred technical solution is that the epoxy resin used in Example 2 is a compound of bisphenol A type epoxy resin and multifunctional epoxy resin with a ratio of (2.5~3.5):(6.5~7.5).

[0139] Example 2 and Example 5 are basically the same, the main difference being that the types of tackifiers used are different. From a technical point of view, the preferred type of tackifier is the solid epoxy resin of Example 2.

[0140] Example 2 and Example 6 are basically the same, the main difference being that the type of curing agent used is different. From the perspective of technical effect, the preferred type of curing agent is the dicyandiamide curing agent of Example 2.

[0141] Example 2 and Example 7 are basically the same, the main difference being that the types of accelerators used are different. From the perspective of technical effect, the preferred type of accelerator is the organic urea of ​​Example 2.

[0142] Example 2 and Example 8 are basically the same, the main difference being the content of the resin composition in the prepreg. Example 2 and Example 9 are basically the same, the main difference being the type of carbon fiber used. From a technical perspective, the carbon fiber in Example 9 is not T700 or T800, resulting in a slightly inferior technical effect.

[0143] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0144] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A prepreg, characterized in that, Includes a reinforcing material and a resin composition attached to the reinforcing material; The reinforcing material is carbon fiber; the resin composition comprises the following components in parts by weight: 100 parts epoxy resin, 0.5 to 10 parts epoxy-containing diluent, 1 to 12.5 parts tackifier, 4 to 10 parts curing agent, and 1 to 5 parts accelerator. The epoxy resin includes one or more of bisphenol A type epoxy resin, multifunctional epoxy resin, and phenolic epoxy resin, wherein the epoxy equivalent of the bisphenol A type epoxy resin and the phenolic epoxy resin is independently 155 g / eq to 220 g / eq; the multifunctional epoxy resin includes , , and One or more of the following; The epoxy-containing diluent includes and One or more of the following; wherein R1 is a C3-C6 alkyl group; n is any integer from 3 to 6; The tackifier includes one or more of phenoxy resin, solid epoxy resin, and acrylate block copolymer.

2. The prepreg according to claim 1, characterized in that, The carbon fiber is a polyacrylonitrile-based carbon fiber.

3. The prepreg according to claim 1, characterized in that, The epoxy resin comprises the bisphenol A type epoxy resin and the multifunctional epoxy resin in a mass ratio of 1:(8~9).

4. The prepreg according to claim 1, characterized in that, The curing agent includes one or more of dicyandiamide curing agent and 4,4'-diaminodiphenyl sulfone; And / or, the accelerator includes one or more of organic urea and imidazole accelerators.

5. The prepreg according to any one of claims 1 to 4, characterized in that, The epoxy resin comprises the multifunctional epoxy resin and the phenolic epoxy resin in a mass ratio of (5~6):

1.

6. The prepreg according to any one of claims 1 to 4, characterized in that, In the prepreg, the mass fraction of the reinforcing material is 60%~77%; And / or, in the prepreg, the resin composition has a mass fraction of 23% to 40%.

7. A method for preparing the prepreg according to any one of claims 1 to 6, characterized in that, Includes the following steps: The resin composition is prepared according to the formulation, and the resin composition is liquefied to prepare an impregnation solution; The reinforcing material is impregnated in the impregnation solution, and after cooling, the prepreg is prepared.

8. The method for preparing the prepreg according to claim 7, characterized in that, The liquefaction temperature is 65℃~85℃.

9. A fiber-reinforced composite material, characterized in that, Formed by curing the prepreg as described in any one of claims 1 to 6.

10. The fiber-reinforced composite material according to claim 9, characterized in that, The composite material has one or more of the following characteristics: (1) The glass transition temperature of the fiber-reinforced composite material is 115℃~250℃; (2) The tensile strength of the fiber-reinforced composite material is 2200MPa~3200MPa; (3) The 0° tensile modulus of the fiber-reinforced composite material is 150 GPa to 175 GPa.

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