Fiber hybrid reinforced prepreg and production process thereof
By introducing glassy carbon hybrid woven fabric and modified flame retardant into carbon fiber prepreg, the problems of high cost and insufficient flame retardancy are solved, and high-performance fiber hybrid reinforced prepreg is realized, which is suitable for high-end fields such as new energy vehicles.
Patent Information
- Application Number
- CN202511632520.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-10
- Publication Date
- 2026-02-24
AI Technical Summary
Existing carbon fiber prepregs are expensive, and epoxy resin matrices lack flame retardancy, which limits their widespread application in new energy vehicles.
By combining glass-carbon hybrid woven fabric with modified flame retardants, and introducing modified flame retardants with multiple flame retardant mechanisms into epoxy resin, and compounding them with accelerators, the flame retardant performance is improved while maintaining excellent mechanical properties.
The resulting fiber-reinforced prepreg meets the UL94 V0 flame retardant standard, possesses excellent mechanical properties, and is suitable for high-end fields such as new energy vehicles.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of fiber reinforced materials technology, specifically relating to a fiber hybrid reinforced prepreg and its production process. Background Technology
[0002] Prepreg is a semi-finished product formed by impregnating a resin matrix onto reinforcing fibers, creating strips or sheets of uniform thickness. It serves as an intermediate material in the manufacture of high-strength composite materials. Commonly used carbon fiber reinforced prepregs are lightweight, high-strength, and exhibit excellent acid and alkali resistance, finding widespread application in various fields such as the automotive, aerospace, rail transportation, and military industries. However, the high cost of carbon fiber limits the widespread use of composite materials made from carbon fiber prepregs in new energy vehicles. Reducing prepreg costs has become a primary issue in the development of lightweight vehicles, and reinforcing prepregs by blending carbon fiber and glass fiber is currently one of the effective methods.
[0003] Carbon fiber / glass fiber hybrid prepregs used as components in new energy vehicles need to meet high fire resistance requirements. However, epoxy resin, which is the matrix material of the prepreg, does not have flame retardancy. Therefore, improving the flame retardancy of fiber hybrid prepregs while ensuring their mechanical properties is a technical problem that needs to be solved. Summary of the Invention
[0004] The purpose of this invention is to provide a fiber-blended reinforced prepreg and its production process to solve the problems in the prior art.
[0005] The objective of this invention can be achieved through the following technical solutions: A fiber-reinforced prepreg is composed of two layers of adhesive film and a glass-carbon hybrid woven fabric laid between the two layers of adhesive film; the adhesive film is prepared by the following steps: Step A1: Melt and mix solid epoxy resin and toughening agent at 90°C to obtain component A; add curing agent, accelerator and modified flame retardant to liquid epoxy resin and mix evenly, grind with a grinder to obtain component B; add component B to component A and stir to mix evenly, remove air bubbles by vacuuming to obtain epoxy resin composition. Step A2: Pour the epoxy resin composition between the two rollers of the coating machine, which is preheated to 65-70℃. The epoxy resin composition is coated onto the release paper by the rotating coating rollers. After cooling, a layer of PE release film is then applied to obtain the adhesive film.
[0006] Further, the weight ratio of the solid epoxy resin, toughening agent, curing agent, accelerator, modified flame retardant, and liquid epoxy resin is 20-30:5:8:3:15-20:60; the solid epoxy resin is epoxy resin E12, the toughening agent is polyvinyl butyral, the curing agent is dicyandiamide, the accelerator is organic urea accelerator UR500, and the liquid epoxy resin is epoxy resin E51.
[0007] Furthermore, the modified flame retardant is prepared through the following steps: Step B1: N,N-Dimethylglucosamine was added to N,N-dimethylamide and mixed evenly. Then phosphoric acid was added, and the mixture was stirred at 130°C for 2 hours. Boric acid was then added, and the mixture was stirred at 130°C for another 2 hours. Finally, urea was added, and the mixture was stirred at 120°C for 1 hour. After filtration, the mixture was washed with ethanol and dried under vacuum at 60°C to obtain a flame retardant intermediate. Under heating conditions, the hydroxyl groups in N,N-dimethylglucosamine underwent esterification reactions with phosphoric acid and boric acid, and then ammonification reactions with urea to obtain a flame retardant intermediate containing phosphate ester groups, borate ester groups, and ammonium ions. Step B2: Add the flame retardant intermediate to the polyetheramine and mix evenly. Then stir and react at 100°C for 30 minutes. The dimethylamine group in the flame retardant intermediate replaces the active hydrogen of the amine group in the polyetheramine. After cooling, the modified flame retardant is obtained.
[0008] Furthermore, the ratio of N,N-dimethylglucosamine, N,N-dimethylamide, phosphoric acid, boric acid, and urea is 10.5g:75mL:17.6-19.6g:9.3-12.4g:15g.
[0009] Furthermore, the ratio of the flame-retardant intermediate to polyetheramine is 18-20g:100g.
[0010] Furthermore, the glass fiber to carbon fiber in the glass-carbon hybrid woven fabric has a mass ratio of 2:3 and a thickness of 0.15 mm.
[0011] Furthermore, the resin content in the prepreg is 42-43 wt%.
[0012] A process for producing a fiber-blended reinforced prepreg includes the following steps: After removing the release paper from one film, the glass carbon composite woven fabric is laid flat on the surface of the lower film. Then, the release paper from another film is removed to serve as the upper film. The side with the release paper removed is laid flat with the glass carbon composite woven fabric facing the surface. The resin is then fully impregnated with the glass carbon composite woven fabric under the action of a hot plate at 80-90℃ and extrusion rollers. After cooling, fiber-reinforced prepreg is obtained.
[0013] Beneficial effects: This invention constructs a flame retardant intermediate with multiple flame retardant mechanisms by sequentially subjecting N,N-dimethylglucosamine to phosphorylation, borate esterification, and ammoniation reactions. The flame retardant intermediate is then grafted onto polyetheramine for modification, resulting in a modified flame retardant that can be uniformly dispersed in an epoxy resin matrix. On one hand, the uniformly dispersed modified flame retardant significantly improves the flame retardant properties of prepregs. During high-temperature combustion, it generates phosphoric acid, polyphosphoric acid, and boric acid, catalyzing the dehydration and carbonization of the resin matrix. This forms non-combustible complex boron-phosphorus carbides on the material surface, isolating heat and oxygen, hindering further combustion of the reinforcing material, and acting as a gas-phase flame retardant during ammonium ion combustion. On the other hand, by replacing the active hydrogen of the amine group in the polyetheramine with the dimethylamine group in the flame retardant intermediate, the reactivity of the polyetheramine is reduced, giving it latency at room temperature. When used in combination with an accelerator, it synergistically enhances the curing speed of the dicyandiamide curing system, while also facilitating the uniform dispersion of the flame retardant intermediate in the epoxy resin and ensuring good compatibility with the epoxy resin, thus avoiding loss of mechanical properties. The glass-carbon hybrid woven fabric used in this invention balances the requirements of low cost and high strength, ensuring the excellent mechanical properties of the prepreg, resulting in a laminate with a tensile strength >670MPa, a flexural strength >840MPa, and a strength >170kJ / m. 2 It has good impact toughness; in addition, the fiber hybrid reinforced prepreg prepared by this invention can meet the UL94 V0 flame retardant standard, which is very suitable for the use needs of high-end fields such as new energy vehicles and rail transit, and has broad application prospects. Detailed Implementation
[0014] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0015] Example 1 This embodiment provides a modified flame retardant, which is prepared through the following steps: Step B1: Add 10.5g of N,N-dimethylglucosamine to 75mL of N,N-dimethylamide and mix well. Then add 17.6g of phosphoric acid and stir at 130℃ for 2h. Then add 12.4g of boric acid and continue stirring at 130℃ for 2h. Finally add 15g of urea and stir at 120℃ for 1h. After filtration, wash with ethanol and dry under vacuum at 60℃ to obtain the flame retardant intermediate. Step B2: Add 18g of flame retardant intermediate to 100g of polyetheramine and mix well. Then stir and react at 100℃ for 30min. After cooling, the modified flame retardant is obtained.
[0016] Example 2 This embodiment provides a modified flame retardant, which is prepared through the following steps: Step B1: Add 10.5g of N,N-dimethylglucosamine to 75mL of N,N-dimethylamide and mix well. Then add 18.6g of phosphoric acid and stir at 130℃ for 2h. Then add 10.9g of boric acid and continue stirring at 130℃ for 2h. Finally add 15g of urea and stir at 120℃ for 1h. After filtration, wash with ethanol and dry under vacuum at 60℃ to obtain the flame retardant intermediate. Step B2: Add 19g of flame retardant intermediate to 100g of polyetheramine and mix well. Then stir and react at 100℃ for 30min. After cooling, the modified flame retardant is obtained.
[0017] Example 3 This embodiment provides a modified flame retardant, which is prepared through the following steps: Step B1: Add 10.5g of N,N-dimethylglucosamine to 75mL of N,N-dimethylamide and mix well. Then add 19.6g of phosphoric acid and stir at 130℃ for 2h. Then add 9.3g of boric acid and continue stirring at 130℃ for 2h. Finally add 15g of urea and stir at 120℃ for 1h. After filtration, wash with ethanol and dry under vacuum at 60℃ to obtain the flame retardant intermediate. Step B2: Add 20g of flame retardant intermediate to 100g of polyetheramine and mix well. Then stir and react at 100℃ for 30min. After cooling, the modified flame retardant is obtained.
[0018] Comparative Example 1 The difference between this comparative example and Example 3 is that boric acid is not added in step B1, while the other raw materials and steps are the same.
[0019] Comparative Example 2 The difference between this comparative example and Example 3 is that urea is not added in step B1, while the other raw materials and steps are the same.
[0020] Comparative Example 3 The difference between this comparative example and Example 3 is that step B2 is omitted, and the flame-retardant intermediate obtained in step B1 is directly used as the modified flame retardant. All other raw materials and steps are the same.
[0021] Example 4 This embodiment provides an adhesive film, which is prepared by the following steps: Step A1: By weight, 20 parts of epoxy resin E12 and 5 parts of polyvinyl butyral are melted and mixed at 90°C to obtain component A; 8 parts of dicyandiamide, 3 parts of organic urea accelerator UR500 and 15 parts of the modified flame retardant prepared in Example 1 are added to 60 parts of epoxy resin E51 and mixed evenly, and then ground with a grinder to obtain component B; component B is added to component A and stirred and mixed evenly, and the air bubbles are removed by vacuum to obtain the epoxy resin composition. Step A2: Pour the epoxy resin composition between the two rollers of the coating machine, which is preheated to 65°C. The epoxy resin composition is coated onto the release paper by the rotating coating rollers. After cooling, a layer of PE release film is then applied to obtain the adhesive film.
[0022] Example 5 This embodiment provides an adhesive film, which is prepared by the following steps: Step A1: By weight, 25 parts of epoxy resin E12 and 5 parts of polyvinyl butyral are melted and mixed at 90°C to obtain component A; 8 parts of dicyandiamide, 3 parts of organic urea accelerator UR500 and 18 parts of the modified flame retardant prepared in Example 2 are added to 60 parts of epoxy resin E51 and mixed evenly, and then ground with a grinder to obtain component B; component B is added to component A and stirred and mixed evenly, and the air bubbles are removed by vacuum to obtain the epoxy resin composition. Step A2: Pour the epoxy resin composition between the two rollers of the coating machine, which is preheated to 68°C. The epoxy resin composition is coated onto the release paper by the rotating coating rollers. After cooling, a layer of PE release film is then applied to obtain the adhesive film.
[0023] Example 6 This embodiment provides an adhesive film, which is prepared by the following steps: Step A1: By weight, 30 parts of epoxy resin E12 and 5 parts of polyvinyl butyral are melted and mixed at 90°C to obtain component A; 8 parts of dicyandiamide, 3 parts of organic urea accelerator UR500 and 20 parts of the modified flame retardant prepared in Example 3 are added to 60 parts of epoxy resin E51 and mixed evenly, and then ground with a grinder to obtain component B; component B is added to component A and stirred and mixed evenly, and the air bubbles are removed by vacuum to obtain the epoxy resin composition. Step A2: Pour the epoxy resin composition between the two rollers of the coating machine preheated to 70°C. The epoxy resin composition is coated onto the release paper by the rotating coating rollers. After cooling, a layer of PE release film is then applied to obtain the adhesive film.
[0024] Comparative Example 4 The difference between this comparative example and Example 6 is that the modified flame retardant prepared in Comparative Example 1 is used to replace the modified flame retardant prepared in Example 3 in an equal amount, while the other raw materials and steps are the same.
[0025] Comparative Example 5 The difference between this comparative example and Example 6 is that the modified flame retardant prepared in Comparative Example 2 is used to replace the modified flame retardant prepared in Example 3 in an equal amount, while the other raw materials and steps are the same.
[0026] Comparative Example 6 The difference between this comparative example and Example 6 is that the modified flame retardant prepared in Comparative Example 3 is used to replace the modified flame retardant prepared in Example 3 in an equal amount, while the other raw materials and steps are the same.
[0027] Example 7 This embodiment provides a fiber-blended reinforced prepreg, which is prepared by the following production process: Two films prepared in Example 4 were used. The release paper of one film was removed to serve as the lower film. A glass-carbon hybrid woven fabric was laid flat on the surface of the lower film. The glass-carbon hybrid woven fabric was model H1K-CGP125, in which the mass ratio of glass fiber to carbon fiber was 2:3 and the thickness was 0.15 mm. Then, the release paper of the other film was removed to serve as the upper film. The side with the release paper removed was laid flat with the glass-carbon hybrid woven fabric facing it. The resin was then fully impregnated into the glass-carbon hybrid woven fabric under the action of an 80°C hot plate and extrusion rollers. After cooling, a fiber-reinforced prepreg with a resin content of 43 wt% was obtained.
[0028] Example 8 This embodiment provides a fiber-blended reinforced prepreg, which is prepared by the following production process: Two films prepared in Example 5 were used. The release paper of one film was removed to serve as the lower film. A glass-carbon hybrid woven fabric was laid flat on the surface of the lower film. The glass-carbon hybrid woven fabric was model H1K-CGP125, in which the mass ratio of glass fiber to carbon fiber was 2:3 and the thickness was 0.15 mm. Then, the release paper of the other film was removed to serve as the upper film. The side with the release paper removed was laid flat with the glass-carbon hybrid woven fabric facing it. The resin was then fully impregnated into the glass-carbon hybrid woven fabric under the action of an 85°C hot plate and extrusion rollers. After cooling, a fiber-reinforced prepreg with a resin content of 42 wt% was obtained.
[0029] Example 9 This embodiment provides a fiber-blended reinforced prepreg, which is prepared by the following production process: Two films prepared in Example 6 were used. The release paper of one film was removed to serve as the lower film. A glass-carbon hybrid woven fabric was laid flat on the surface of the lower film. The glass-carbon hybrid woven fabric was model H1K-CGP125, in which the mass ratio of glass fiber to carbon fiber was 2:3 and the thickness was 0.15 mm. Then, the release paper of the other film was removed to serve as the upper film. The side with the release paper removed was laid flat with the glass-carbon hybrid woven fabric facing it. The resin was then fully impregnated into the glass-carbon hybrid woven fabric under the action of a 90°C hot plate and extrusion rollers. After cooling, a fiber-reinforced prepreg with a resin content of 42 wt% was obtained.
[0030] Comparative Example 6 The difference between this comparative example and Example 9 is that the film prepared in Comparative Example 4 is used instead of the film prepared in Example 6, while the other raw materials and steps are the same.
[0031] Comparative Example 7 The difference between this comparative example and Example 9 is that the film prepared in Comparative Example 5 is used instead of the film prepared in Example 6, while the other raw materials and steps are the same.
[0032] Comparative Example 8 The difference between this comparative example and Example 9 is that the film prepared in Comparative Example 6 is used instead of the film prepared in Example 6, while the other raw materials and steps are the same.
[0033] The prepregs prepared in Examples 7-9 and Comparative Examples 1-3 were subjected to performance tests. Fiber-reinforced prepreg blocks were laid up according to the requirements of a 2mm thick laminate for tensile testing and a 3mm thick laminate for bending testing. The laminates were cured for 60 minutes under a hot-pressing process at 0.5MPa / 125℃ to obtain laminate samples. Finally, the samples were cut to the required test dimensions using a carving machine. Tensile tests were performed according to ASTM D3039, bending tests according to ASTM D790, and impact tests according to GB / T 2571-1995. The flame retardancy rating was tested according to the UL94 vertical burning method. The test results are shown in Table 1. Table 1 As can be seen from the data in Table 1, the fiber-reinforced prepregs prepared in Examples 7-9 have higher tensile strength and flexural strength, exhibiting excellent mechanical and flame-retardant properties. Compared with Example 9, Comparative Examples 7 and 8 lack the introduction of borate ester groups and ammonium ions, respectively, resulting in a slight decrease in mechanical and flame-retardant properties. Compared with Example 9, Comparative Example 9 lacks the modification grafting of polyetheramine, resulting in uneven dispersion of the modified flame retardant in the prepreg, leading to a significant decrease in mechanical properties and the inability to achieve optimal flame-retardant properties.
[0034] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.
[0035] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A fiber-blended reinforced prepreg, characterized in that, It is composed of two layers of adhesive film and a glass-carbon composite woven fabric laid between the two layers of adhesive film; the adhesive film is prepared by the following steps: Step A1: Melt and mix solid epoxy resin and toughening agent at 90°C to obtain component A; add curing agent, accelerator and modified flame retardant to liquid epoxy resin and mix evenly, grind with a grinder to obtain component B; add component B to component A and stir to mix evenly, remove air bubbles by vacuuming to obtain epoxy resin composition. Step A2: Pour the epoxy resin composition between the two rollers of the coating machine, which is preheated to 65-70℃. The epoxy resin composition is coated onto the release paper by the rotating coating rollers. After cooling, a layer of PE release film is then applied to obtain the adhesive film.
2. The fiber-reinforced prepreg according to claim 1, characterized in that, The weight ratio of the solid epoxy resin, toughening agent, curing agent, accelerator, modified flame retardant, and liquid epoxy resin is 20-30:5:8:3:15-20:60; the solid epoxy resin is epoxy resin E12, the toughening agent is polyvinyl butyral, the curing agent is dicyandiamide, the accelerator is organic urea accelerator UR500, and the liquid epoxy resin is epoxy resin E51.
3. The fiber-reinforced prepreg according to claim 1, characterized in that, The modified flame retardant is prepared by the following steps: Step B1: Add N,N-dimethylglucosamine to N,N-dimethylamide and mix well. Then add phosphoric acid and stir at 130°C for 2 hours. Then add boric acid and continue stirring at 130°C for 2 hours. Finally, add urea and stir at 120°C for 1 hour. After filtration, wash with ethanol and dry under vacuum at 60°C to obtain the flame retardant intermediate. Step B2: Add the flame retardant intermediate to the polyetheramine and mix well. Then stir and react at 100°C for 30 minutes. After cooling, the modified flame retardant is obtained.
4. The fiber-reinforced prepreg according to claim 3, characterized in that, The ratio of N,N-dimethylglucosamine, N,N-dimethylamide, phosphoric acid, boric acid and urea is 10.5g:75mL:17.6-19.6g:9.3-12.4g:15g.
5. The fiber-reinforced prepreg according to claim 3, characterized in that, The ratio of the flame-retardant intermediate to polyetheramine is 18-20g:100g.
6. The fiber-blended reinforced prepreg according to claim 1, characterized in that, The glass-carbon hybrid woven fabric has a glass fiber to carbon fiber mass ratio of 2:3 and a thickness of 0.15 mm.
7. The fiber-blended reinforced prepreg according to claim 1, characterized in that, The resin content in the prepreg is 42-43 wt%.
8. The production process of a fiber-blended reinforced prepreg according to claim 1, characterized in that, Includes the following steps: After removing the release paper from one film, the glass carbon composite woven fabric is laid flat on the surface of the lower film. Then, the release paper from another film is removed to serve as the upper film. The side with the release paper removed is laid flat with the glass carbon composite woven fabric facing the surface. The resin is then fully impregnated with the glass carbon composite woven fabric under the action of a hot plate at 80-90℃ and extrusion rollers. After cooling, fiber-reinforced prepreg is obtained.