A toughened prepreg

Abstract

The present invention provides a toughened prepreg comprising: a base film made from a first component comprising a base resin, a first curing agent, and optionally a first accelerator; a toughening layer made from a first component comprising a toughening layer resin, a second curing agent, and optionally a second accelerator; and reinforcing fibers, wherein the toughening layer resin has a lower curing temperature than the base resin. The low viscosity of the base resin in this prepreg facilitates process operation and provides excellent impregnation effects. The resulting prepreg maintains good adhesion, and the resulting laminate exhibits high post-impact compressive strength.

Description

Technical Field

[0001] The present invention relates to the technical field of resin-based composite materials, in particular to a toughened prepreg. Background Art

[0002] Advanced resin-based composites boast high specific modulus and strength, fatigue resistance, corrosion resistance, and design flexibility. They are widely and increasingly used in a wide range of fields, including aerospace, military, and automotive lightweighting. Epoxy resin composites are one of the most widely used resin-based composites, but due to their high crosslink density after curing, epoxy resins exhibit high brittleness and poor toughness.

[0003] Furthermore, in these fields, composite materials are primarily produced in the form of carbon fiber prepregs. The interlayers in laminates produced from these prepregs are the composite's weak epoxy layer, which makes them susceptible to delamination when subjected to external forces, significantly reducing the mechanical properties of the laminates. Brittle resin composites are generally considered the first generation, toughened and modified resin-based composites are collectively referred to as the second generation, and high-toughness resin-based composites are considered the third generation.

[0004] Research has found that the toughening effect of the matrix resin significantly transfers to continuous fiber-reinforced composites. For most thermosetting matrix materials, the fracture toughness of the bulk resin can increase by nearly a dozen times after toughening, while the interlaminar fracture toughness of the composites composed of these materials improves only slightly. Furthermore, toughening the matrix resin can lead to poor impregnation of the carbon fibers and changes in the tactile feel of the prepreg, increasing the difficulty of composite preparation and altering conventional processing routes.

[0005] To address this issue, interlaminar toughening technology is used to address a series of process issues caused by directly dissolving or dispersing high levels of thermoplastic resin in a resin matrix. This technology involves placing a thermoplastic resin in the form of a film or powder between two carbon fiber layers impregnated with a low-viscosity resin matrix. This specifically improves the interlaminar toughness of the composite material, significantly increasing its CAI (compressive impact strength). However, interlaminar toughening also presents other challenges, such as reduced prepreg viscosity and poor draping properties. Summary of the Invention

[0006] In view of the problems in the above-mentioned prior art that the thermoplastic resin toughened epoxy resin matrix leads to high system viscosity, high requirements for mixing process and subsequent coating process, and poor fiber impregnation effect, the toughening between prepreg layers leads to a decrease in prepreg viscosity, and the low compression strength of the laminate after impact is difficult to meet the performance requirements of the composite material, one of the purposes of the present invention is to provide a toughened prepreg, whose matrix resin viscosity is low, which is conducive to process operation and has good impregnation effect. The prepared prepreg can maintain good viscosity and the prepared laminate has the advantages of high compression strength after impact.

[0007] A second object of the present invention is to provide a method for preparing a toughened prepreg corresponding to the first object.

[0008] A third object of the present invention is to provide a laminate corresponding to the above-mentioned object.

[0009] A fourth object of the present invention is to provide an application of a toughened prepreg or laminate corresponding to the above object.

[0010] To achieve one of the above purposes, the technical solution adopted by the present invention is as follows:

[0011] A toughened prepreg comprising:

[0012] A base adhesive film, which is made of a first component including a base resin, a first curing agent and optionally a first accelerator;

[0013] Reinforcement fibers located on the base film;

[0014] a toughening layer covering the surface of the base film, which is made of a second component including a toughening layer resin, a second curing agent and optionally a second accelerator; and

[0015] Wherein, the curing temperature of the toughening layer resin is lower than the curing temperature of the base resin.

[0016] The toughened prepreg provided by the present invention mainly solves the problems of hot-melt prepregs using thermoplastic resins to toughen the resin matrix, resulting in increased system viscosity, poor process operability, and poor carbon fiber impregnation effect, as well as the problem of conventional interlayer toughening causing decreased prepreg viscosity and poor drapeability. The present invention proposes a method in which the toughening layer resin is cured before the matrix resin, solving the problems of increased system viscosity and poor processability caused by matrix toughening. At the same time, the prepared prepreg has suitable viscosity and drapeability, the toughening layer is fixed between layers, and the laminate has high post-impact compressive strength, and can be used in the preparation of various carbon fiber composite main load-bearing structures and non-load-bearing parts.

[0017] In some preferred embodiments of the present invention, the surface density of the base film is 15 g / m 2 ~60g / m 2 .

[0018] In some preferred embodiments of the present invention, the surface density of the toughening layer is 5g / m 2 ~35g / m 2 .

[0019] In some preferred embodiments of the present invention, the surface density of the reinforcing fibers is 40 g / m 2 ~80g / m 2 .

[0020] In some preferred embodiments of the present invention, the matrix resin and the toughening layer resin are different and are independently selected from one or more of epoxy resins and modified epoxy resins.

[0021] In some preferred embodiments of the present invention, the epoxy resin is selected from one or more of glycidyl ether epoxy resins, glycidyl ester epoxy resins and glycidyl amine epoxy resins.

[0022] In some preferred embodiments of the present invention, the matrix resin and the toughening layer resin are independently selected from one or more of E44 epoxy resin, E51 epoxy resin, XB9721 epoxy resin and 671 epoxy resin.

[0023] In some preferred embodiments of the present invention, the modified epoxy resin comprises bisphenol A and epoxy resin. More preferably, the mass content of bisphenol A is 10% to 30% based on the total weight of the modified epoxy resin.

[0024] According to the present invention, the matrix resin includes two, three, four or five selected from glycidyl ether epoxy resins, glycidyl ester epoxy resins and glycidyl amine epoxy resins, preferably two, three, four or five selected from E44 epoxy resin, E51 epoxy resin, XB9721 epoxy resin and 671 epoxy resin.

[0025] According to the present invention, the matrix resin further comprises a modified epoxy resin. In some specific embodiments of the present invention, the modified epoxy resin comprises, in parts by weight:

[0026] 60-80 parts of E51 epoxy resin;

[0027] 20-40 parts of XB9721 epoxy resin

[0028] 10-30 parts of bisphenol A.

[0029] According to the present invention, the toughening layer resin includes two, three, four or five selected from glycidyl ether epoxy resins, glycidyl ester epoxy resins and glycidyl amine epoxy resins, preferably two, three, four or five selected from E44 epoxy resin, E51 epoxy resin, XB9721 epoxy resin and 671 epoxy resin.

[0030] According to the present invention, the toughening layer resin further comprises bisphenol A. Preferably, the mass percentage of bisphenol A in the toughening layer resin is 10 wt % to 30 wt %.

[0031] In some preferred embodiments of the present invention, the first curing agent and the second curing agent are the same or different, and are each independently selected from at least one of an amine curing agent, an acid anhydride curing agent, a linear phenolic curing agent, a polyester resin curing agent, a polyurethane curing agent, a styrene-maleic anhydride copolymer resin curing agent and a polysulfide rubber curing agent, and are preferably at least one of 4,4'-diaminodiphenyl sulfone, diaminodiphenylmethane and dicyandiamide.

[0032] According to the present invention, in the first component, the amount of the first curing agent is 10 wt% to 80 wt% of the base resin, preferably 20 wt% to 60 wt%.

[0033] According to the present invention, in the second component, the amount of the first curing agent is 1 wt% to 80 wt% of the toughening layer resin, preferably 2 wt% to 50 wt%.

[0034] In some preferred embodiments of the present invention, the first accelerator and the second accelerator are the same or different, and are each independently selected from at least one of amines, phenols, substituted ureas, imidazoles and their salts, boron trifluoride complexes, metal organic salts and phosphine accelerators, preferably at least one of triphenylphosphine and organic urea accelerators.

[0035] According to the present invention, in the first component, the amount of the first accelerator is 0 wt% to 10 wt% of the base resin, preferably 0.05 wt% to 5 wt%.

[0036] According to the present invention, in the first component, the amount of the second accelerator is 0 wt% to 10 wt% of the toughening layer resin, preferably 0.05 wt% to 5 wt%.

[0037] In some preferred embodiments of the present invention, the reinforcing fibers are selected from at least one of carbon fibers, aramid fibers, glass fibers, and basalt fibers. Preferably, the reinforcing fibers are in the form of continuous unidirectional fibers or fabrics.

[0038] In some preferred embodiments of the present invention, the reinforcing fibers are configured to be formed between two layers of the base adhesive films, and the toughening layer is configured to cover the surface of the base adhesive films.

[0039] In some preferred embodiments of the present invention, the toughening layer is configured to cover the upper surface of the base adhesive film.

[0040] To achieve the second of the above objectives, the technical solutions adopted by the present invention are as follows:

[0041] A method for preparing the toughened prepreg according to any one of the above embodiments comprises:

[0042] S1. The first component is subjected to film-forming treatment, preferably by a hot melt coating machine to coat the first component on the surface of the release paper to obtain a base film;

[0043] S2. The second component is subjected to film-forming treatment, preferably by a hot melt coating machine to coat the second component on the release paper surface to obtain a toughening layer;

[0044] S3. The reinforcing fibers are formed on the base film, preferably on a prepreg machine equipped with multiple winding and unwinding stations, the base film is impregnated with fibers to obtain a prepreg intermediate;

[0045] S4. Covering the toughening layer on the surface of the prepreg intermediate, preferably the upper surface, to obtain the prepreg.

[0046] According to the present invention, impregnating the fibers with a matrix film is a commonly used method in the art. The impregnation process and conditions can be conventionally employed in the prior art. The equipment used is also conventionally employed in prepreg processing, such as coating machines and prepreg machines.

[0047] To achieve the third of the above objectives, the technical solutions adopted by the present invention are as follows:

[0048] A laminated board is obtained by laminating and curing the toughened prepreg according to any one of the above embodiments or the toughened prepreg obtained by the preparation method according to any one of the above embodiments.

[0049] In some preferred embodiments of the present invention, the curing process is two-stage curing or three-stage curing, wherein the conditions for the two-stage curing include: the temperature of the first-stage curing is 100°C to 150°C, and the time is 0.1h to 5h, and the temperature of the second-stage curing is 150°C to 200°C, and the time is 0.1h to 5h; the conditions for the three-stage curing include: the temperature of the first-stage curing is 100°C to 140°C, and the time is 0.1h to 5h, the temperature of the second-stage curing is 150°C to 170°C, and the time is 0.1h to 5h, and the temperature of the third-stage curing is 170°C to 200°C, and the time is 0.1h to 5h.

[0050] To achieve the fourth objective above, the present invention adopts the following technical solutions:

[0051] A toughened prepreg according to any one of the above embodiments, a toughened prepreg prepared according to the preparation method according to any one of the above embodiments, or a laminate according to any one of the above embodiments is used in aerospace, military industry or automobiles.

[0052] The beneficial effects of the present invention are at least in the following aspects:

[0053] First, the interlayer toughening is carried out by using toughening layers, and the viscosity of the matrix resin system is low, which is beneficial to improving the process operability and the carbon fiber impregnation effect.

[0054] Secondly, the toughening layer resin has a suitable viscosity, which avoids the problem of conventional interlayer toughening causing the prepreg viscosity to decrease and the draping property to deteriorate.

[0055] Third, the curing temperature of the toughening layer resin is lower than that of the matrix resin. When preparing the composite material, the toughening layer resin is first cured with the matrix resin to form an interlayer resin-rich layer in the composite material, which significantly improves the CAI of the composite material. DETAILED DESCRIPTION

[0056] The present invention is described in detail below through examples, but the protection scope of the present invention is not limited to the following description.

[0057] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or those recommended by the manufacturer. All reagents or instruments used, if the manufacturer is not specified, are conventional products that can be obtained through commercial channels.

[0058] [Example 1]

[0059] 1) Preparation of substrate film

[0060] a) The modified epoxy resin formula consists of:

[0061] E51 epoxy resin: 70 parts

[0062] XB9721 epoxy resin: 30 parts

[0063] Bisphenol A: 20 parts

[0064] Triphenylphosphine: 0.1 part

[0065] b) The matrix film formula is composed of:

[0066] Modified epoxy resin obtained: 120 parts

[0067] E51 epoxy resin: 50 parts

[0068] 4,4'-Diaminodiphenyl sulfone: 45 parts

[0069] Mixing process steps: Heat E51 epoxy resin, XB9721 epoxy resin, and bisphenol A to 120°C to dissolve, add triphenylphosphine, and heat to 180°C for 3 hours to obtain a modified epoxy resin. The modified epoxy resin, E51 epoxy resin, and 4,4'-diaminodiphenyl sulfone are then mixed at 70°C to obtain the resin matrix.

[0070] c) Resin matrix coating:

[0071] Pour the above resin matrix into the resin tank of the coating machine and evenly coat the resin matrix on the release paper at a coating temperature of 70°C. The surface density of the resin matrix film is 25g / m 2 .

[0072] 2) Preparation of toughening layer

[0073] a) The toughening layer resin formula is composed of:

[0074] E51 epoxy resin: 100 parts

[0075] Bisphenol A: 20 parts

[0076] Triphenylphosphine: 0.1 part

[0077] Dicyandiamide: 4 parts

[0078] Organic urea accelerator: 3 parts

[0079] Mixing process steps: heat E51 epoxy resin and bisphenol A to 120°C to dissolve, add triphenylphosphine, heat to 180°C and react for 3 hours, then cool to 70°C, add dicyandiamide and organic urea accelerator and mix to obtain the toughening layer resin.

[0080] b) Toughening layer resin coating:

[0081] Pour the toughening layer resin into the resin tank of the coating machine and evenly coat the toughening layer resin on the release paper at a coating temperature of 70°C. The surface density of the toughening layer is 15g / m 2 .

[0082] 3) Preparation of high toughness prepreg:

[0083] Toray T700×12k carbon fiber was used to prepare the fiber with a surface density of 100g / m 2 Prepreg, place two rolls of matrix resin film on the upper and lower unwinding stations at the front end of the prepreg machine respectively, and place the prepreg toughening layer on the unwinding station in the middle of the prepreg machine. At the first and second heating rollers and heating plates, the upper and lower layers of matrix film complete the impregnation of the unidirectionally arranged carbon fibers. Then roll up the upper layer of release paper, unwind the prepreg toughening layer from the middle unwinding station, cover it on the surface of the prepreg, and complete the bonding of the toughening layer to the surface of the prepreg at the third heating roller and heating plate. After cooling on the cooling plate, roll up the upper layer of release paper, cover it with PE film, and finally complete the winding of the prepreg. Among them, the temperature of the first and second heating zones of the prepreg machine is 100°C, and the temperature of the third heating zone is 50°C. 4) Preparation and performance evaluation of laminates:

[0084] Prepreg was cut to appropriate dimensions and layered according to GB / T 21239-2007. The layers were laid in the order [45 / 0 / -45 / 90]S. The prepreg was then cured in an autoclave at 120°C for 2 hours followed by 180°C for 2 hours, with the toughening layer resin cured at 120°C and the matrix fully cured at 180°C. The cured laminates were cut to produce test specimens measuring 150 mm × 100 mm × 5 mm. Post-impact compressive strength testing was performed on these specimens according to GB / T 21239-2007. The results are shown in Table 1.

[0085] [Example 2]

[0086] The method of Example 1 is followed, except that the base film formulation is as follows:

[0087] E51 epoxy resin: 100 parts

[0088] 4,4'-Diaminodiphenyl sulfone: 33 parts

[0089] Mixing process steps: E51 epoxy resin and 4,4'-diaminodiphenyl sulfone are heated to 120°C to dissolve, and the viscosity of the system reaches 18-45 Pa·s at 70°C to obtain a base film.

[0090] [Example 3]

[0091] The method of Example 1 is followed, except that the base film formulation is as follows:

[0092] E51 epoxy resin: 40 parts

[0093] 671 epoxy resin: 60 parts

[0094] 4,4'-Diaminodiphenyl sulfone: 20 parts

[0095] [Example 4]

[0096] The method of Example 1 is the same as that of Example 1, except that the surface density of the resin matrix film is 40 g / m 2 .

[0097] [Example 5]

[0098] The method of Example 1 is followed, except that the toughening layer density is 5 g / m 2 .

[0099] [Example 6]

[0100] The method of Example 1 is followed, except that the density of the toughened surface is 25 g / m 2 .

[0101] [Example 7]

[0102] The method of Example 1 is followed, except that 2) the toughening layer is prepared.

[0103] 2) Preparation of toughening layer

[0104] a) The toughening layer resin formula is composed of:

[0105] E51 epoxy resin: 40 parts

[0106] 671 epoxy resin: 60 parts

[0107] Dicyandiamide: 3 parts

[0108] Organic urea accelerator: 2 parts

[0109] Mixing process steps: heat E51 epoxy resin and bisphenol A to 120°C to dissolve, add triphenylphosphine, heat to 180°C and react for 3 hours, then cool to 70°C, add dicyandiamide and organic urea accelerator and mix to obtain the toughening layer resin.

[0110] [Example 8]

[0111] The method of Example 1 was followed, except for 2) preparation of the toughening layer and 4) preparation and performance evaluation of the laminate.

[0112] 2) Preparation of toughening layer

[0113] a) The toughening layer resin formula is composed of:

[0114] E51 epoxy resin: 100 parts

[0115] Diaminodiphenylmethane: 30 parts

[0116] Mixing process steps: E51 epoxy resin and diaminodiphenylmethane are heated to 80°C to dissolve, and the viscosity of the system reaches 18-45 Pa·s at 70°C to obtain the toughening layer resin.

[0117] 4) Laminate preparation and performance evaluation:

[0118] Prepreg was cut to appropriate dimensions and layered according to GB / T 21239-2007. The layers were laid in the order [45 / 0 / -45 / 90]S. The prepreg was then cured in an autoclave at a curing temperature of 120°C for 1 hour, 160°C for 1 hour, and 180°C for 2 hours. The toughening layer resin was cured at 160°C, and the matrix resin was fully cured at 180°C. The cured laminates were cut into test specimens measuring 150 mm × 100 mm × 5 mm. Post-impact compressive strength testing was performed on these specimens according to GB / T 21239-2007. The results are shown in Table 1.

[0119] [Example 9]

[0120] The method of Example 8 was followed, except for 2) the toughening layer was prepared.

[0121] 2) Preparation of toughening layer

[0122] a) The toughening layer resin formula is composed of:

[0123] E44 epoxy resin: 100 parts

[0124] Diaminodiphenylmethane: 25 parts

[0125] Mixing process steps: E44 epoxy resin and diaminodiphenylmethane are heated to 80°C to dissolve, and the viscosity of the system reaches 18-45 Pa·s at 70°C to obtain the toughening layer resin.

[0126] [Example 10]

[0127] The method of Example 1 was followed, except for 1) preparation of the base film and 4) preparation and performance evaluation of the laminate.

[0128] 1) Preparation of substrate film

[0129] a) The modified epoxy resin formula consists of:

[0130] E51 epoxy resin: 70 parts

[0131] XB9721 epoxy resin: 30 parts

[0132] Bisphenol A: 20 parts

[0133] Triphenylphosphine: 0.1 part

[0134] b) The resin matrix film formula is composed of:

[0135] Modified epoxy resin obtained: 120 parts

[0136] E51 epoxy resin: 50 parts

[0137] Diaminodiphenylmethane: 40 parts

[0138] Mixing process steps: Heat E51 epoxy resin, XB9721 epoxy resin, and bisphenol A to 120°C to dissolve, add triphenylphosphine, and heat to 180°C for 3 hours to obtain a modified epoxy resin. Then, mix the modified epoxy resin, E51 epoxy resin, and diaminodiphenylmethane at 70°C to obtain a resin matrix.

[0139] c) Resin matrix coating:

[0140] Pour the above resin matrix into the resin tank of the coating machine and evenly coat the resin matrix on the release paper at a coating temperature of 70°C. The surface density of the resin matrix film is 25g / m 2 .

[0141] 4) Laminate preparation and performance evaluation:

[0142] Prepreg was cut to appropriate dimensions and layered according to GB / T 21239-2007. The layers were laid in the order [45 / 0 / -45 / 90]S. The prepreg was then cured in an autoclave at a curing temperature of 120°C for 1 hour, 160°C for 1 hour, and 180°C for 2 hours. The toughening layer resin was cured at 160°C, and the matrix resin was fully cured at 180°C. The cured laminates were cut into test specimens measuring 150 mm × 100 mm × 5 mm. Post-impact compressive strength testing was performed on these specimens according to GB / T 21239-2007. The results are shown in Table 1.

[0143] [Comparative Example 1]

[0144] The method of Example 1 was followed, except that no toughening layer was prepared and no toughening layer was inserted during the preparation of the prepreg.

[0145] [Comparative Example 2]

[0146] The method of Example 10 was followed, except that no toughening layer was prepared and no toughening layer was inserted during the preparation of the prepreg.

[0147] [Comparative Example 3]

[0148] The method of Example 1 is followed, except that the toughening layer resin formula is the same as the base film formula.

[0149] [Comparative Example 4]

[0150] The method of Example 1 is followed, except that the toughening layer resin formula and the base film formula are swapped.

[0151] Table 1 Test results of compression strength of laminates after impact

[0152] project Compression strength after impact (MPa) Example 1 303 Example 2 256 Example 3 296 Example 4 289 Example 5 267 Example 6 292 Example 7 294 Example 8 289 Example 9 295 Example 10 306 Comparative Example 1 164 Comparative Example 2 181 Comparative Example 3 206 Comparative Example 4 227

[0153] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation of the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein. On the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A toughened prepreg comprising: A base adhesive film, which is made of a first component including a base resin, a first curing agent and optionally a first accelerator; Reinforcement fibers located on the base film; a toughening layer covering the surface of the base film, which is made of a second component including a toughening layer resin, a second curing agent and optionally a second accelerator; and Wherein, the curing temperature of the toughening layer resin is lower than the curing temperature of the base resin.

2. The toughened prepreg according to claim 1, characterized in that The surface density of the base film is 15g / m 2 ~60g / m 2 ; And / or, the surface density of the toughening layer is 5g / m 2 ~35g / m 2 ; And / or, the surface density of the reinforcing fiber is 40g / m 2 ~80g / m 2 .

3. The toughened prepreg according to claim 1, characterized in that The matrix resin and the toughening layer resin are different and are independently selected from one or more of epoxy resin and modified epoxy resin.

4. The toughened prepreg according to claim 3, characterized in that The epoxy resin is selected from one or more of glycidyl ether epoxy resins, glycidyl ester epoxy resins and glycidyl amine epoxy resins. And / or, the modified epoxy resin includes bisphenol A and epoxy resin.

5. The toughened prepreg according to claim 4, characterized in that The epoxy resin is selected from one or more of E44 epoxy resin, E51 epoxy resin, XB9721 epoxy resin and 671 epoxy resin. And / or, based on the total weight of the modified epoxy resin, the mass content of bisphenol A is 10% to 30%.

6. The toughened prepreg according to any one of claims 1 to 5, characterized in that The first curing agent and the second curing agent are the same or different and are independently selected from at least one of amine curing agents, acid anhydride curing agents, linear phenolic curing agents, polyester resin curing agents, polyurethane curing agents, styrene-maleic anhydride copolymer resin curing agents and polysulfide rubber curing agents.

7. The toughened prepreg according to claim 6, characterized in that The first curing agent and the second curing agent are the same or different and are independently selected from at least one of 4,4'-diaminodiphenyl sulfone, diaminodiphenylmethane and dicyandiamide.

8. The toughened prepreg according to any one of claims 1 to 5, characterized in that The first accelerator and the second accelerator are the same or different and are independently selected from at least one of amines, phenols, substituted ureas, imidazoles and salts thereof, boron trifluoride complexes, metal organic salts and phosphine accelerators.

9. The toughened prepreg according to claim 8, characterized in that The first accelerator and the second accelerator are the same or different and are independently selected from at least one of triphenylphosphine and organic urea accelerators.

10. The toughened prepreg according to any one of claims 1 to 5, characterized in that The reinforcing fiber is selected from at least one of carbon fiber, aramid fiber, glass fiber and basalt fiber.

11. The toughened prepreg according to claim 10, characterized in that The reinforcing fibers are in the form of continuous unidirectional fibers or fabrics.

12. The toughened prepreg according to any one of claims 1 to 5, characterized in that The reinforcing fibers are configured to be formed between two layers of the base adhesive films, and the toughening layer is configured to cover the surface of the base adhesive film.

13. The toughened prepreg according to claim 12, characterized in that The toughening layer is configured to cover the upper surface of the base adhesive film.

14. A method for preparing the toughened prepreg according to any one of claims 1 to 13, comprising: S1. The first component is subjected to film-forming treatment to obtain a base film; S2 is subjected to film-forming treatment of the second component to obtain a toughening layer; S3. The reinforcing fibers are formed on the base film to obtain a prepreg intermediate; S4. Covering the toughening layer on the surface of the prepreg intermediate to obtain the prepreg.

15. A method for preparing the toughened prepreg according to claim 14, characterized in that: Step S1 includes applying the first component on the surface of the release paper using a hot melt coating machine to obtain a base film; And / or, step S2 includes coating the second component on the surface of the release paper using a hot melt coating machine to obtain a toughening layer; And / or, step S3 includes impregnating the fibers with the matrix film on a prepreg machine equipped with a plurality of winding and unwinding stations to obtain a prepreg intermediate; And / or, step S4 includes covering the toughening layer on the upper surface of the prepreg intermediate to obtain the prepreg.

16. A laminated board, which is obtained by laminating and curing the toughened prepreg according to any one of 1 to 13 or the toughened prepreg obtained by the preparation method according to claim 14 or 15.

17. The laminate according to claim 16, wherein The curing process is a two-stage curing or a three-stage curing, wherein the conditions for the two-stage curing include: the temperature of the first-stage curing is 100°C~150°C, the time is 0.1h~5h, and the temperature of the second-stage curing is 150°C~200°C, and the time is 0.1h~5h; the conditions for the three-stage curing include: the temperature of the first-stage curing is 100°C~140°C, the time is 0.1h~5h, the temperature of the second-stage curing is 150°C~170°C, the time is 0.1h~5h, and the temperature of the third-stage curing is 170°C~200°C, and the time is 0.1h~5h.

18. Use of the toughened prepreg according to any one of claims 1 to 13, or the toughened prepreg prepared by the preparation method according to claim 14 or 15, or the laminate according to claim 16 or 17 in aerospace, military industry or automobiles.