Aviation thermosetting composite material with low forming temperature and preparation method thereof

Abstract

The invention discloses a low-forming-temperature thermosetting composite material for aviation and a preparation method of the low-forming-temperature thermosetting composite material, and belongs to the technical field of thermosetting materials for aviation. 5 to 15 parts of cyanate ester monomer; 0.3 to 2.0 parts of a divalent metal salt; 80 to 100 parts of thermosetting resin; and 10-20 parts of a toughening agent. According to the invention, the amine curing agent, the cyanate ester monomer and the divalent metal salt are utilized to innovatively prepare the ternary composite curing agent system capable of remarkably improving the curing forming rate. By utilizing the advantage that amino and phenolic hydroxyl groups in the benzoxazine resin can accelerate the curing rate of epoxy and bismaleimide resin, the toughening agent has the effects of improving toughness and autocatalysis. The reinforced thermosetting composite material prepared by the preparation method disclosed by the invention has relatively low forming temperature and excellent use performance, and can be used for manufacturing high-temperature-resistant aviation resin-based composite material parts.

Description

Technical Field

[0001] The present invention belongs to the technical field of aviation thermosetting materials, and in particular relates to an aviation thermosetting composite material with a low molding temperature and a preparation method thereof. Background Art

[0002] Carbon fiber-reinforced resin-based composites are one of the key materials used extensively in the aviation sector today and in the future. Currently, high-temperature-resistant carbon fiber-reinforced resin-based composites for aviation use primarily consist of high-temperature curing epoxy composites (molding temperature: 180±5°C) and bismaleimide and cyanate ester composites (molding temperature: 200±5°C). Lowering the molding and curing temperature of composite materials is crucial for reducing manufacturing costs, shortening manufacturing cycles, and minimizing deformation and internal quality risks associated with temperature fluctuations. However, lowering the molding temperature typically reduces the material's operating temperature, which in turn reduces mechanical properties and shortens its shelf life.

[0003] Traditional high-temperature epoxy composites cured at 180°C typically have a glass transition temperature (Tg) of around 210-230°C. To address this issue, some research teams have attempted to incorporate latent imidazole curing agents into epoxy composite systems, lowering the molding and curing temperature to 100°C. The Tg (a key indicator of heat resistance) is around 140-150°C, but this approach is only applicable to medium-temperature curing epoxy systems. Furthermore, some reports have proposed adding autocatalytic components to high-temperature epoxy resins, lowering the molding temperature of epoxy composites, but also reducing the curing temperature. Compared to epoxy composites, there are fewer reports on reducing the Tg of bismaleimide and cyanate ester composites to below 200°C. Some reports have shown that the addition of organic oximes to bismaleimide resins can lower the molding temperature of the composites to around 180°C, but this also lowers the Tg (below the 260°C for 200°C curing).

[0004] For example, the existing Chinese patent CN116606529B discloses a low-temperature curing epoxy resin and a preparation method, a prepreg, a composite material and an application. The low-temperature curing epoxy resin includes the following components in parts by weight: 50 to 80 parts of epoxy resin, 10 to 20 parts of curing agent, 2 to 5 parts of accelerator, 10 to 20 parts of toughening agent, and 0.1 to 1 part of anti-corrosion agent; the epoxy resin includes 10 to 20 parts by weight of low-viscosity liquid hydantoin-type epoxy resin, 10 to 25 parts by weight of novolac epoxy resin, 10 to 20 parts by weight of solid bisphenol A-type epoxy resin and 10 to 20 parts by weight of low-viscosity bisphenol F-type epoxy resin, and the accelerator is a latent imidazole accelerator.

[0005] Existing Chinese patent CN109265922B discloses a high-toughness autocatalytic epoxy resin and its preparation method. The resin comprises 1-15 parts by weight of a hyperbranched polysiloxane containing multiple reactive functional groups, 60-90 parts by weight of a bisphenol A epoxy resin, and 50-60 parts by weight of an anhydride curing agent. Because the hyperbranched polysiloxane in this resin system contains both tertiary and primary amine reactive functional groups, the resin system exhibits excellent toughness.

[0006] Existing Chinese patent CN111793193A discloses a solvent-free, 180°C-resistant, ultra-low-viscosity epoxy resin matrix and its preparation method. The epoxy resin matrix is ​​composed of a difunctional epoxy resin, a multifunctional epoxy resin, and a liquid curing system. The epoxy resin matrix preparation method includes thoroughly mixing the components with high-speed stirring and vacuum degassing to obtain the epoxy resin matrix. After curing at a medium temperature (150°C), the matrix has a glass transition temperature (Tg) greater than 180°C.

[0007] In summary, existing improved solutions still fail to fully address the degradation of performance associated with lowering the molding temperature, and are not universally applicable. Therefore, the optimal solution is to lower the curing temperature without compromising the material's operating temperature and mechanical properties, and to be applicable to a wide range of materials. Summary of the Invention

[0008] The object of the present invention is to provide a thermosetting composite material with a low molding temperature for aviation and a preparation method thereof, in order to solve the above-mentioned problems.

[0009] The present invention is mainly achieved through the following technical solutions: A low-molding-temperature thermosetting composite material for aviation use, comprising the following components, calculated in parts by weight: Amine curing agent: 10-20 parts; Cyanate monomer: 5-15 parts; Divalent metal salt: 0.3~2.0 parts; Thermosetting resin: 80~100 parts; Toughening agent: 10~20 parts; The toughening agent includes any one or more of thermoplastic polyarylene ether resin, benzoxazine resin and diallyl bisphenol A.

[0010] In order to better realize the present invention, further, the toughening agent includes thermoplastic phenolphthalein type polyaryletherketone resin, bisphenol type benzoxazine resin and diallylbisphenol A, and the mass ratio is 100:20~40:0~10.

[0011] In order to better realize the present invention, further, the thermosetting resin includes any one or more of bisphenol A epoxy resin, diphenylmethane bismaleimide resin, and novolac epoxy resin.

[0012] In order to better implement the present invention, further, the thermosetting resin includes bisphenol A type epoxy resin and bismaleimide resin, or the thermosetting resin includes diphenylmethane type bismaleimide resin and E54 epoxy resin.

[0013] In order to better realize the present invention, further, the amine curing agent is an aromatic amine curing agent; and the cyanate ester monomer is a bisphenol cyanate ester monomer.

[0014] In order to better realize the present invention, further, the amine curing agent is 3'3-diaminodiphenyl sulfone, and the cyanate ester monomer is bisphenol A cyanate ester monomer.

[0015] In order to better implement the present invention, further, the divalent metal salt is a divalent metal halide.

[0016] In order to better realize the present invention, further, the divalent metal salt is ZnCl2 or CoCl2.

[0017] The present invention is mainly achieved through the following technical solutions: A method for preparing a thermosetting composite material with a low molding temperature for aviation use comprises the following steps: Step S1: adding an amine curing agent and a cyanate ester monomer into a reaction kettle at a temperature of 100-120° C., mixing, and stirring for 20-40 minutes; Step S2: Cooling the reaction kettle to 70-90° C., then adding a divalent metal salt and stirring for 10-20 minutes to prepare a composite curing agent; Step S3: adding the thermosetting resin and toughening agent into a reaction kettle at a temperature of 110-130° C., mixing, and stirring for 30-60 minutes; Step S4: cooling the temperature of the reaction kettle to 50-70° C.; adding the composite curing agent prepared in step S2; and mixing evenly to prepare a reinforced thermosetting composite material.

[0018] The beneficial effects of the present invention are as follows: (1) The present invention innovatively designs the curing system in the resin formulation, preparing a composite curing agent component based on an amine curing agent, a cyanate ester monomer, and a divalent metal salt, thereby improving its curing and molding activity at a specific temperature. Specifically, the present invention utilizes the synergistic curing effect of diamine, cyanate ester monomer, and divalent metal salt on epoxy, bismaleimide, and other composite materials to innovatively prepare a ternary composite curing agent system that can significantly improve the curing and molding rate.

[0019] (2) The present invention also improves the toughening system, so that the toughening agent has the functions of both toughening and accelerating curing and molding. Specifically, the present invention takes advantage of the fact that the amino and phenolic hydroxyl groups in benzoxazine resin can accelerate the curing rate of epoxy and bismaleimide resins, and innovatively adds them to the toughening formula of the resin, so that the toughening component used in this solution has the effects of improving toughness and self-catalysis.

[0020] (3) The improved curing and toughening systems of the present invention are applicable to improving various high-temperature epoxy, bismaleimide, and cyanate ester thermosetting resin-based composite materials. The reinforced thermosetting composites prepared by the present invention have both low molding temperatures and excellent performance, and can be used to manufacture high-temperature resistant aviation resin-based composite parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the glass transition temperature test curve of the aviation carbon fiber reinforced thermosetting composite material in Example 1. DETAILED DESCRIPTION

[0022] Example 1: A method for preparing a thermosetting composite material with a low molding temperature for aviation use comprises the following steps: As shown in Table 1, weigh 20 parts of 3,3-diaminodiphenyl sulfone and 10 parts of bisphenol A cyanate monomer, heat to 115°C, and stir for 25 minutes. After the temperature drops to approximately 75°C, add 0.4 parts of ZnCl2 catalyst and stir for 15 minutes. Once the mixture is uniform, a composite curing agent is obtained, which is then placed in a low-temperature environment.

[0023] The reactor temperature was then raised to 125°C, and 80 parts of E54 epoxy resin, 20 parts of novolac epoxy resin, and 12 parts of a toughening agent (thermoplastic phenolphthalein polyaryletherketone resin and bisphenol-benzoxazine resin, in a ratio of 3:1) were added. After stirring for 45 minutes, the temperature was lowered to 60°C, and the prepared composite curing agent was added. After stirring evenly, the final resin was obtained.

[0024] Then the above resin was cured at 160°C for 3h to obtain a cured product. Figure 1 As shown, the glass transition temperature of the cured product was measured to be 228.5°C.

[0025] Example 2: A method for preparing a thermosetting composite material with a low molding temperature for aviation use comprises the following steps: As shown in Table 1, weigh 20 parts of 3,3-diaminodiphenyl sulfone and 10 parts of bisphenol A cyanate monomer, heat to 115°C, and stir for 25 minutes. Once the temperature drops to approximately 70°C, add 0.5 parts of CoCl2 catalyst and stir for 15 minutes. Once the mixture is uniform, a composite curing agent is obtained, which is then placed in a low-temperature environment.

[0026] The reactor temperature was then raised to 125°C, and 85 parts of E54 epoxy resin, 15 parts of novolac epoxy resin, and 12 parts of a toughening agent (thermoplastic phenolphthalein polyaryletherketone resin and bisphenol-benzoxazine resin, in a ratio of 3:1) were added. After stirring for 50 minutes, the temperature was lowered to 60°C, and the prepared composite curing agent was added. After stirring evenly, the final resin was obtained.

[0027] The resin was then cured at 160°C for 3 hours to obtain a cured product. The glass transition temperature of the cured product was measured to be 230.1°C.

[0028] Example 3: A method for preparing a thermosetting composite material with a low molding temperature for aviation use comprises the following steps: As shown in Table 1, weigh 10 parts of 3',3'-diaminodiphenyl sulfone and 10 parts of bisphenol A cyanate monomer, heat to 120°C, and stir for 30 minutes. After the temperature drops to approximately 75°C, add 0.4 parts of ZnCl2 catalyst and stir for 10 minutes. Once the mixture is uniform, a composite curing agent is obtained, which is then placed in a low-temperature environment.

[0029] The reactor temperature was then raised to 120°C, and 100 parts of diphenylmethane-based bismaleimide resin, 8 parts of E54 resin, and 13 parts of a toughening agent (thermoplastic phenolphthalein-based polyaryletherketone resin and bisphenol-based benzoxazine resin, in a ratio of 2:1) were added. After stirring for 60 minutes, the temperature was lowered to 60°C, and the prepared composite curing agent was added. After uniform stirring, the final resin was obtained.

[0030] The resin was then cured at 180°C for 5 hours to obtain a cured product, the glass transition temperature of which was measured to be 255.3°C.

[0031] Example 4: A method for preparing a thermosetting composite material with a low molding temperature for aviation use comprises the following steps: As shown in Table 1, weigh 10 parts of 3,3-diaminodiphenyl sulfone and 10 parts of bisphenol A cyanate monomer, heat to 120°C, and stir for 30 minutes. After the temperature drops to approximately 75°C, add 0.3 parts of ZnCl2 catalyst and stir for 10 minutes. Once the mixture is uniform, a composite curing agent is obtained, which is then placed in a low-temperature environment.

[0032] The reactor temperature was then raised to 115°C, followed by the addition of 100 parts of diphenylmethane-based bismaleimide resin, 7 parts of E54 resin, and 16 parts of a toughening agent (a mixture of thermoplastic phenolphthalein-based polyaryletherketone resin, bisphenol-based benzoxazine resin, and diallylbisphenol A in a ratio of 100:28:10). After stirring for 60 minutes, the temperature was lowered to 60°C, and the prepared composite curing agent was added. After uniform mixing, the final resin was obtained.

[0033] The resin was then cured at 180°C for 5 hours to obtain a cured product. The glass transition temperature of the cured product was measured to be 253.4°C.

[0034] Example 5: A method for preparing a thermosetting composite material with a low molding temperature for aviation use comprises the following steps: As shown in Table 1, weigh 8 parts of 3,3-diaminodiphenyl sulfone and 13 parts of bisphenol A cyanate monomer, heat to 120°C, and stir for 30 minutes. After the temperature drops to approximately 75°C, add 0.4 parts of CoCl2 catalyst and stir for 10 minutes. Once the mixture is uniform, a composite curing agent is obtained, which is then placed in a low-temperature environment.

[0035] The reactor temperature was then raised to 125°C, and 100 parts of diphenylmethane-based bismaleimide resin, 6 parts of E54 resin, and 15 parts of a toughening agent (thermoplastic phenolphthalein-based polyaryletherketone resin and diallylbisphenol A, in a ratio of 10:1) were added. After stirring for 60 minutes, the temperature was lowered to 60°C, and the prepared composite curing agent was added. After stirring evenly, the final resin was obtained.

[0036] The resin was then cured at 180°C for 5 hours to obtain a cured product, the glass transition temperature of which was measured to be 251.1°C.

[0037] Table 1 The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A low-molding-temperature thermosetting composite material for aviation, characterized in that: Calculated by weight, it includes the following components: Amine curing agent: 10-20 parts; Cyanate monomer: 5-15 parts; Divalent metal salt: 0.3~2.0 parts; Thermosetting resin: 80~100 parts; Toughening agent: 10~20 parts; The toughening agent includes any one or more of thermoplastic polyarylene ether resin, benzoxazine resin and diallyl bisphenol A.

2. The low-molding-temperature thermosetting composite material for aviation according to claim 1, characterized in that: The toughening agent comprises thermoplastic phenolphthalein type polyaryletherketone resin, bisphenol type benzoxazine resin and diallylbisphenol A, and the mass ratio is 100:20-40:0-10.

3. The low-molding-temperature thermosetting composite material for aviation according to claim 1, characterized in that: The thermosetting resin includes any one or more of bisphenol A epoxy resin, diphenylmethane bismaleimide resin, and phenolic epoxy resin.

4. The low-molding-temperature thermosetting composite material for aviation according to claim 3, characterized in that: The thermosetting resin includes bisphenol A epoxy resin and bismaleimide resin, or the thermosetting resin includes diphenylmethane bismaleimide resin and E54 epoxy resin.

5. The low-molding-temperature thermosetting composite material for aviation according to claim 1, characterized in that: The amine curing agent is an aromatic amine curing agent; the cyanate ester monomer is a bisphenol cyanate ester monomer.

6. The low-molding-temperature thermosetting composite material for aviation according to claim 5, characterized in that: The amine curing agent is 3'3-diaminodiphenyl sulfone, and the cyanate monomer is bisphenol A cyanate monomer.

7. The low-molding-temperature thermosetting composite material for aviation according to claim 1, characterized in that: The divalent metal salt is a divalent metal halide.

8. The low-molding-temperature thermosetting composite material for aviation according to claim 7, characterized in that: The divalent metal salt is ZnCl2 or CoCl2.

9. A method for preparing a thermosetting composite material with a low molding temperature for aviation, characterized in that: The following steps are involved: Step S1: adding an amine curing agent and a cyanate ester monomer into a reaction kettle at a temperature of 100-120° C., mixing, and stirring for 20-40 minutes; Step S2: Cooling the reaction kettle to 70-90° C., then adding a divalent metal salt and stirring for 10-20 minutes to prepare a composite curing agent; Step S3: adding the thermosetting resin and toughening agent into a reaction kettle at a temperature of 110-130° C., mixing, and stirring for 30-60 minutes; Step S4: cooling the temperature of the reaction kettle to 50-70° C.; adding the composite curing agent prepared in step S2; and mixing evenly to prepare a reinforced thermosetting composite material.

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