Liquid forming epoxy resin as well as preparation method and application thereof

Abstract

The invention provides liquid molding epoxy resin as well as a preparation method and application thereof, and relates to the technical field of composite material manufacturing. The liquid molding epoxy resin is mainly prepared from the following components in parts by mass: 100 parts of bifunctional epoxy resin, 5 to 20 parts of tetrafunctional epoxy resin, 5 to 15 parts of benzoxazine resin, 5 to 15 parts of polyfunctional epoxy-terminated polyhedral oligomeric silsesquioxane, 90 to 110 parts of a curing agent, 0.5 to 2 parts of an accelerant and 10 to 20 parts of a flame retardant. The technical problems that flame-retardant epoxy resin in the prior art is poor in manufacturability, high in curing shrinkage rate, low in mechanical property after curing and not resistant to aging are solved, and the heat resistance, impact resistance and ultraviolet aging resistance of the resin are effectively improved while the flame-retardant function is guaranteed; and the curing shrinkage rate is obviously reduced.

Description

Technical Field

[0001] The invention relates to the technical field of composite material manufacturing, and in particular to a liquid molding epoxy resin and a preparation method and application thereof. Background Art

[0002] Composite materials are lightweight and strong, and have great application value in the aerospace field. In the field of civil aviation, the role of composite materials is even more prominent. Replacing traditional metal materials with them can improve fuel efficiency and load-carrying capacity, thereby reducing operating costs and improving flight performance. Aviation safety is the primary factor to be considered when designing and manufacturing large passenger aircraft, among which flame retardant performance is crucial; composite materials used in large passenger aircraft must have good flame retardant properties to meet strict safety standards.

[0003] At present, liquid molding processes, such as resin transfer molding (RTM) and vacuum assisted resin injection (VARI), are favored because of their low cost, high efficiency and near-net-shape advantages for complex structures. The use of liquid molding processes to manufacture aviation composites can further reduce manufacturing costs. However, the liquid molding process requires the resin to have the characteristics of low viscosity and long open period, which often causes large curing shrinkage, and in severe cases, it will cause deformation and cracking of the composite material after curing; at the same time, in order to achieve the flame retardant functional requirements, the addition of flame retardant fillers will also increase the viscosity of the liquid molding resin, shorten the open period, and reduce the mechanical properties. In short, the contradiction between the processability requirements of liquid molding resins and their curing shrinkage problems and flame retardant functional requirements has become a bottleneck restricting the flame retardant liquid molding resins for aviation composites. In addition, civil aviation composites are prone to aging and deterioration during long-term service due to environmental factors such as ultraviolet rays and humidity, which will further threaten structural performance and flight safety.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0006] One of the purposes of the present invention is to provide a liquid molding epoxy resin, which not only ensures flame retardant functionality but also takes into account better heat resistance, impact resistance and UV aging resistance, and has a low curing shrinkage rate.

[0007] The second object of the present invention is to provide a method for preparing a liquid molding epoxy resin, which has a simple process, high efficiency, high product qualification rate, and is suitable for large-scale industrial production.

[0008] The third object of the present invention is to provide an application of a liquid molding epoxy resin, which is beneficial to comprehensively improve the performance of aviation composite materials and has outstanding application effects.

[0009] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0010] In the first aspect, a liquid molding epoxy resin is mainly prepared from the following components in parts by mass:

[0011] 100 parts of difunctional epoxy resin, 5-20 parts of tetrafunctional epoxy resin, 5-15 parts of benzoxazine resin, 5-15 parts of multifunctional epoxy-terminated cage-type polysilsesquioxane, 90-110 parts of curing agent, 0.5-2 parts of accelerator, and 10-20 parts of flame retardant.

[0012] Furthermore, the difunctional epoxy resin includes at least one of bisphenol A epoxy resin, bisphenol F epoxy resin and hydrogenated bisphenol A epoxy resin.

[0013] Furthermore, the tetrafunctional epoxy resin includes at least one of tetraglycidyl diaminodiphenylmethane, tetraglycidyl ditoluene diamine and tetraglycidyl-1,3-bis(aminomethylcyclohexane).

[0014] Furthermore, the benzoxazine resin includes at least one of bisphenol A type benzoxazine resin, bisphenol F type benzoxazine resin, aromatic diamine type benzoxazine resin, dicyclopentadiene type benzoxazine resin, phenol type benzoxazine resin, DOPO type benzoxazine resin and phenolphthalein type benzoxazine resin.

[0015] Furthermore, the functionality of the multi-functional epoxy-terminated cage-type polysilsesquioxane is 2-8.

[0016] Further, the curing agent includes an anhydride curing agent;

[0017] Preferably, the acid anhydride curing agent includes at least one of methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride and dodecylsuccinic anhydride.

[0018] Furthermore, the promoter includes at least one of triethylamine, dimethylaminomethylphenol, tris(dimethylaminomethyl)phenol and 2-ethyl-4-methylimidazole.

[0019] Further, the inorganic additive flame retardant includes at least one of red phosphorus, phosphorus pentoxide, ammonium polyphosphate, aluminum hydroxide, magnesium hydroxide, zinc borate, barium metaborate, boron oxide, antimony trioxide, tin oxide, tin hydroxide, molybdenum oxide, ammonium molybdate, zirconium oxide, zirconium hydroxide and calcium aluminate;

[0020] Preferably, the particle size of the inorganic additive flame retardant is no more than 10 μm.

[0021] In a second aspect, a method for preparing the liquid molding epoxy resin described in any one of the above items comprises the following steps:

[0022] The components are mixed in proportion to obtain the liquid molding epoxy resin.

[0023] A third aspect is a use of the liquid molding epoxy resin described in any one of the above items in the manufacture of aviation composite materials.

[0024] Compared with the prior art, the present invention has at least the following beneficial effects:

[0025] The liquid molding epoxy resin provided by the present invention is a modified epoxy resin compounded with an inorganic additive flame retardant, an organic benzoxazine resin and a cage-type polyhedral oligomeric silsesquioxane (POSS), which not only effectively improves the heat resistance, impact resistance and ultraviolet aging resistance of the resin while realizing the flame retardant functionality of the resin, but also significantly reduces the curing shrinkage of the resin; in short, under the coordinated cooperation of various components and their proportions, the liquid molding epoxy resin of the present invention not only meets the requirements of low viscosity and long open period in the liquid molding process of composite materials, but also has the performance characteristics of high toughness, high temperature resistance, flame retardancy, low curing shrinkage and aging resistance.

[0026] The preparation method of the liquid molding epoxy resin provided by the invention has simple process, high efficiency, high product qualification rate and is suitable for large-scale industrial production.

[0027] The application of the liquid molding epoxy resin provided by the present invention is beneficial to comprehensively improving the performance of aviation composite materials and has outstanding application effects. DETAILED DESCRIPTION

[0028] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] The existing technology generally only focuses on improving the flame retardant functionality of the resin by adding or compounding different types of flame retardants, but ignores the fact that the curing shrinkage of the resin may cause molding quality problems such as resin deformation and cracking. At the same time, the large amount of flame retardant added will also increase the viscosity of the resin, making it unable to meet the process requirements of liquid molding. In addition, after the resin is cured, the incompatible flame retardant components may become stress concentration points and induce cracks, resulting in a decrease in the mechanical properties of the resin. At the same time, the existing technology is also unable to meet the requirements of aviation composite materials for the toughness and aging resistance of the matrix resin.

[0030] Therefore, in order to solve the technical problems of poor processability, high curing shrinkage, reduced mechanical properties after curing, and poor aging resistance of existing flame retardant epoxy resins, the technical solution of the present invention is specially proposed.

[0031] According to a first aspect of the present invention, there is provided a liquid molding epoxy resin, which is mainly prepared from the following components in parts by mass:

[0032] 100 parts of difunctional epoxy resin, 5-20 parts of tetrafunctional epoxy resin, 5-15 parts of benzoxazine resin, 5-15 parts of multifunctional terminal epoxy cage polysilsesquioxane, 90-110 parts of curing agent, 0.5-2 parts of accelerator, and 10-20 parts of inorganic additive flame retardant.

[0033] In the present invention, typical but non-limiting mass fractions of tetrafunctional epoxy resin are, for example, 5 parts, 10 parts, 15 parts, and 20 parts; typical but non-limiting mass fractions of benzoxazine resin are, for example, 5 parts, 10 parts, and 15 parts; typical but non-limiting mass fractions of multifunctional epoxy-terminated cage-type polysilsesquioxane are, for example, 5 parts, 10 parts, and 15 parts; typical but non-limiting mass fractions of curing agent are, for example, 90 parts, 95 parts, 100 parts, 105 parts, and 110 parts; typical but non-limiting mass fractions of accelerator are, for example, 0.5 parts, 1 parts, 1.5 parts, and 2 parts; typical but non-limiting mass fractions of inorganic additive flame retardant are, for example, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, and 20 parts.

[0034] The liquid molding epoxy resin provided by the present invention is a modified epoxy resin compounded with an inorganic additive flame retardant, an organic benzoxazine resin and a cage-type polyhedral oligomeric silsesquioxane (POSS), which not only effectively improves the heat resistance, impact resistance and ultraviolet aging resistance of the resin while realizing the flame retardant functionality of the resin, but also significantly reduces the curing shrinkage of the resin.

[0035] In summary, with the coordinated cooperation of various components and their proportions, the liquid molding epoxy resin of the present invention not only meets the requirements of low viscosity and long open period in the liquid molding process of composite materials, but also has the performance characteristics of high toughness, high temperature resistance, flame retardancy, low curing shrinkage and aging resistance.

[0036] In a preferred embodiment, the difunctional epoxy resin includes but is not limited to at least one of bisphenol A epoxy resin, bisphenol F epoxy resin and hydrogenated bisphenol A epoxy resin.

[0037] In a preferred embodiment, the tetrafunctional epoxy resin includes, but is not limited to, at least one of tetraglycidyldiaminodiphenylmethane, tetraglycidylxylenediamine and tetraglycidyl-1,3-bis(aminomethylcyclohexane).

[0038] In a preferred embodiment, the benzoxazine resin includes but is not limited to at least one of bisphenol A type benzoxazine resin, bisphenol F type benzoxazine resin, aromatic diamine type benzoxazine resin, dicyclopentadiene type benzoxazine resin, phenol type benzoxazine resin, DOPO type benzoxazine resin and phenolphthalein type benzoxazine resin.

[0039] In the present invention, the low curing shrinkage and intrinsic flame retardant properties of benzoxazine resin are utilized to modify epoxy resin by compounding with additive flame retardant, thereby achieving flame retardant functionality of the resin and reducing the curing shrinkage of the resin. In addition, the addition of benzoxazine resin can appropriately reduce the amount of inorganic additive flame retardant, thereby avoiding the problem of excessive increase in resin viscosity.

[0040] In a preferred embodiment, the functionality of the multi-functional epoxy-terminated cage polysilsesquioxane may be 2-8, and typical but non-limiting functionalities thereof are, for example, 2, 3, 4, 5, 6, 7, and 8.

[0041] In the present invention, the cage-type polysilsesquioxane is used for compounding, which can improve the impact resistance and aging resistance of the cured resin, and is beneficial to comprehensively improve the processability, molding quality and use performance of the modified resin.

[0042] In a preferred embodiment, the curing agent includes but is not limited to anhydride curing agent.

[0043] In the present invention, the acid anhydride curing agent includes but is not limited to at least one of methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride and dodecylsuccinic anhydride.

[0044] In a preferred embodiment, the promoter includes but is not limited to at least one of triethylamine, dimethylaminomethylphenol, tris(dimethylaminomethyl)phenol and 2-ethyl-4-methylimidazole.

[0045] In a preferred embodiment, the inorganic additive flame retardant includes but is not limited to at least one of red phosphorus, phosphorus pentoxide, ammonium polyphosphate, aluminum hydroxide, magnesium hydroxide, zinc borate, barium metaborate, boron oxide, antimony trioxide, tin oxide, tin hydroxide, molybdenum oxide, ammonium molybdate, zirconium oxide, zirconium hydroxide and calcium aluminate; wherein the particle size of the inorganic additive flame retardant does not exceed 10 μm.

[0046] The inorganic additive flame retardant used in the present invention can further cooperate with the organic benzoxazine resin and the cage-type polysilsesquioxane, and the components work synergistically, not only making the modified resin meet the requirements of the liquid molding process for low viscosity and long open period, but also ensuring that the mechanical properties of the resin after curing do not decrease, while also improving the glass transition temperature of the resin and the impact resistance before and after ultraviolet aging.

[0047] According to a second aspect of the present invention, there is provided a method for preparing the liquid molding epoxy resin described in any one of the above, comprising the following steps:

[0048] The components are mixed in proportion to obtain liquid molding epoxy resin.

[0049] The preparation method of the liquid molding epoxy resin provided by the invention has simple process, high efficiency, high product qualification rate and is suitable for large-scale industrial production.

[0050] A typical preparation method of a liquid molding epoxy resin comprises the following steps:

[0051] (a) mixing 100 parts by mass of a difunctional epoxy resin and 5-20 parts by mass of a tetrafunctional epoxy resin, preheating the mixture to 90° C., adding 5-15 parts by mass of a benzoxazine resin and 5-15 parts by mass of a multifunctional epoxy-terminated cage-type polysilsesquioxane, and stirring the mixture to obtain a first premixed resin;

[0052] (b) cooling the first premixed resin to below 60° C., adding 90-110 parts by mass of anhydride curing agent and 0.5-2 parts by mass of accelerator, and stirring evenly to obtain a second premixed resin;

[0053] (c) adding 10-20 parts by mass of an inorganic additive flame retardant to the second premixed resin and stirring the mixture to obtain a flame retardant low shrinkage epoxy resin for liquid molding.

[0054] According to a third aspect of the present invention, there is provided a use of any of the above-mentioned liquid molding epoxy resins in manufacturing aviation composite materials.

[0055] The application of the liquid molding epoxy resin provided by the present invention is beneficial to comprehensively improving the performance of aviation composite materials and has outstanding application effects.

[0056] The liquid molding epoxy resin of the present invention is used in the manufacture of composite materials, which can effectively improve the molding quality and performance of existing products, and also has the significant advantages of easy process implementation, low cost and high efficiency.

[0057] The present invention is further described below by way of examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or directly purchased from the market.

[0058] Example 1

[0059] A method for preparing a liquid molding epoxy resin comprises the following steps:

[0060] (a) mixing 100 parts of E51 epoxy resin and 20 parts of tetraglycidyl diaminodiphenylmethane by weight, preheating to 90° C., adding 5 parts of aromatic diamine benzoxazine resin and 5 parts of difunctional epoxy-terminated cage-type polysilsesquioxane, stirring evenly, and obtaining a first premixed resin;

[0061] (b) cooling the first premixed resin to below 60° C., adding 100 parts by mass of methyltetrahydrophthalic anhydride and 1 part by mass of 2-ethyl-4-methylimidazole, and stirring evenly to obtain a second premixed resin;

[0062] (c) Add 10 parts by mass of aluminum hydroxide (with a particle size not exceeding 10 μm) to the second premixed resin and stir evenly to obtain a liquid molding epoxy resin.

[0063] Example 2

[0064] A method for preparing a liquid molding epoxy resin comprises the following steps:

[0065] (a) mixing 100 parts of E51 epoxy resin and 20 parts of tetraglycidyl diaminodiphenylmethane by weight, preheating to 90° C., adding 10 parts of aromatic diamine benzoxazine resin and 10 parts of difunctional epoxy-terminated cage-type polysilsesquioxane, and stirring evenly to obtain a first premixed resin;

[0066] (b) cooling the first premixed resin to below 60° C., adding 100 parts by mass of methyltetrahydrophthalic anhydride and 1 part by mass of 2-ethyl-4-methylimidazole, and stirring evenly to obtain a second premixed resin;

[0067] (c) Add 10 parts by mass of aluminum hydroxide (with a particle size not exceeding 10 μm) to the second premixed resin and stir evenly to obtain a liquid molding epoxy resin.

[0068] Example 3

[0069] A method for preparing a liquid molding epoxy resin comprises the following steps:

[0070] (a) mixing 100 parts of E51 epoxy resin and 20 parts of tetraglycidyl diaminodiphenylmethane by weight, preheating to 90° C., adding 15 parts of aromatic diamine benzoxazine resin and 15 parts of difunctional epoxy-terminated cage-type polysilsesquioxane, and stirring evenly to obtain a first premixed resin;

[0071] (b) cooling the first premixed resin to below 60° C., adding 100 parts by mass of methyltetrahydrophthalic anhydride and 1 part by mass of 2-ethyl-4-methylimidazole, and stirring evenly to obtain a second premixed resin;

[0072] (c) Add 10 parts by mass of aluminum hydroxide (with a particle size not exceeding 10 μm) to the second premixed resin and stir evenly to obtain a liquid molding epoxy resin.

[0073] Example 4

[0074] A method for preparing a liquid molding epoxy resin comprises the following steps:

[0075] (a) mixing 100 parts of E51 epoxy resin and 20 parts of tetraglycidyl diaminodiphenylmethane by weight, preheating to 90° C., adding 10 parts of aromatic diamine benzoxazine resin and 10 parts of difunctional epoxy-terminated cage-type polysilsesquioxane, and stirring evenly to obtain a first premixed resin;

[0076] (b) cooling the first premixed resin to below 60° C., adding 100 parts by mass of methyltetrahydrophthalic anhydride and 1 part by mass of 2-ethyl-4-methylimidazole, and stirring evenly to obtain a second premixed resin;

[0077] (c) Add 15 parts by mass of aluminum hydroxide (with a particle size not exceeding 10 μm) to the second premixed resin and stir evenly to obtain a liquid molding epoxy resin.

[0078] Example 5

[0079] A method for preparing a liquid molding epoxy resin comprises the following steps:

[0080] (a) mixing 100 parts of E51 epoxy resin and 20 parts of tetraglycidyl diaminodiphenylmethane by weight, preheating to 90° C., adding 10 parts of aromatic diamine benzoxazine resin and 10 parts of difunctional epoxy-terminated cage-type polysilsesquioxane, and stirring evenly to obtain a first premixed resin;

[0081] (b) cooling the first premixed resin to below 60° C., adding 100 parts by mass of methyltetrahydrophthalic anhydride and 1 part by mass of 2-ethyl-4-methylimidazole, and stirring evenly to obtain a second premixed resin;

[0082] (c) Add 20 parts by mass of aluminum hydroxide (with a particle size not exceeding 10 μm) to the second premixed resin and stir evenly to obtain a liquid molding epoxy resin.

[0083] Comparative Example 1

[0084] A method for preparing a liquid molding epoxy resin comprises the following steps:

[0085] 100 parts of E51 epoxy resin and 20 parts of tetraglycidyl diaminodiphenylmethane were mixed uniformly by mass, and then 100 parts of methyltetrahydrophthalic anhydride and 1 part of 2-ethyl-4-methylimidazole were added and stirred uniformly to obtain a liquid molding epoxy resin.

[0086] Comparative Example 2

[0087] A method for preparing a liquid molding epoxy resin comprises the following steps:

[0088] By mass, 100 parts of E51 epoxy resin and 20 parts of tetraglycidyl diaminodiphenylmethane were mixed and preheated to 90°C, and then 10 parts of aromatic diamine type benzoxazine resin were added and stirred evenly. After that, the mixture was cooled to below 60°C, 100 parts of methyltetrahydrophthalic anhydride and 1 part of 2-ethyl-4-methylimidazole were added and stirred evenly to obtain a liquid molding epoxy resin.

[0089] Comparative Example 3

[0090] A method for preparing a liquid molding epoxy resin comprises the following steps:

[0091] By mass, 100 parts of E51 epoxy resin and 20 parts of tetraglycidyldiaminodiphenylmethane were mixed, 100 parts of methyltetrahydrophthalic anhydride and 1 part of 2-ethyl-4-methylimidazole were added, and stirred evenly. Then, 10 parts of aluminum hydroxide were added thereto, and stirred evenly to obtain a liquid molding epoxy resin.

[0092] Comparative Example 4

[0093] A method for preparing a liquid molding epoxy resin comprises the following steps:

[0094] By mass, 100 parts of E51 epoxy resin and 20 parts of tetraglycidyldiaminodiphenylmethane were mixed and preheated to 90°C, and then 10 parts of difunctional terminal epoxy cage polysilsesquioxane were added and stirred evenly. After that, the mixture was cooled to below 60°C, 100 parts of methyltetrahydrophthalic anhydride and 1 part of 2-ethyl-4-methylimidazole were added and stirred evenly to obtain a liquid molding epoxy resin.

[0095] Test example

[0096] The performance of the resin products obtained in the embodiments and comparative examples was tested, and the results are shown in Table 1.

[0097] The test method is as follows:

[0098] According to GB / T 22235, the viscosity of the resin at 70°C and the gel time at 100°C were tested by a rotational rheometer. The fresh resin was cured at 90°C for 1h and 130°C for 2h to prepare a resin casting. The flame retardant grade and limiting oxygen index of the cured resin were tested by the vertical combustion method according to GB / T 2408. The volume shrinkage of the cured resin was tested according to GB / T 15223. According to GB / T 14522, the cured resin was subjected to an ultraviolet aging test using a UVA-340 fluorescent ultraviolet lamp for 360h. According to GB / T 2567, the tensile strength, modulus and notched impact strength of the cured resin before and after aging were tested. According to GB / T40396, the glass transition temperature of the cured resin was tested using a dynamic thermomechanical analyzer at a heating rate of 5°C / min from room temperature to 200°C.

[0099] Table 1

[0100]

[0101] It can be seen from the performance data recorded in Table 1 that the present invention not only realizes the flame retardant functionality of the resin, but also improves the heat resistance, impact resistance and UV aging resistance of the resin, while significantly reducing the curing shrinkage of the resin by compounding modified epoxy resin with inorganic additive flame retardant, organic benzoxazine resin and cage polysilsesquioxane.

[0102] By comparing the resin properties of the embodiments and the comparative examples, it can be seen that the benzoxazine resin and the inorganic additive flame retardant can cooperate with each other to exert a flame retardant effect, thereby reducing the amount of the inorganic additive flame retardant added, so that the resin product meets the requirements of low viscosity and long open period of the liquid molding process, and ensures that the mechanical properties of the resin after curing do not decrease; cage-type polysilsesquioxane can also cooperate with the inorganic additive flame retardant to exert a flame retardant effect, and at the same time can also improve the glass transition temperature of the resin, as well as the impact resistance before and after UV aging.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A liquid molding epoxy resin, characterized in that: It is mainly prepared from the following components by mass: 100 parts of difunctional epoxy resin, 5-20 parts of tetrafunctional epoxy resin, 5-15 parts of benzoxazine resin, 5-15 parts of multifunctional terminal epoxy cage polysilsesquioxane, 90-110 parts of curing agent, 0.5-2 parts of accelerator, and 10-20 parts of inorganic additive flame retardant.

2. The liquid molding epoxy resin according to claim 1, characterized in that: The difunctional epoxy resin includes at least one of bisphenol A epoxy resin, bisphenol F epoxy resin and hydrogenated bisphenol A epoxy resin.

3. The liquid molding epoxy resin according to claim 1, characterized in that: The tetrafunctional epoxy resin includes at least one of tetraglycidyl diaminodiphenylmethane, tetraglycidyl ditoluene diamine and tetraglycidyl-1,3-bis(aminomethylcyclohexane).

4. The liquid molding epoxy resin according to any one of claims 1 to 3, characterized in that: The benzoxazine resin includes at least one of bisphenol A type benzoxazine resin, bisphenol F type benzoxazine resin, aromatic diamine type benzoxazine resin, dicyclopentadiene type benzoxazine resin, phenol type benzoxazine resin, DOPO type benzoxazine resin and phenolphthalein type benzoxazine resin.

5. The liquid molding epoxy resin according to any one of claims 1 to 3, characterized in that: The functionality of the multi-functional epoxy-terminated cage-type polysilsesquioxane is 2-8.

6. The liquid molding epoxy resin according to claim 1, characterized in that: The curing agent includes an anhydride curing agent; Preferably, the acid anhydride curing agent includes at least one of methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride and dodecylsuccinic anhydride.

7. The liquid molding epoxy resin according to claim 1, characterized in that: The accelerator includes at least one of triethylamine, dimethylaminomethylphenol, tris(dimethylaminomethyl)phenol and 2-ethyl-4-methylimidazole.

8. The liquid molding epoxy resin according to claim 1, characterized in that: The inorganic additive flame retardant includes at least one of red phosphorus, phosphorus pentoxide, ammonium polyphosphate, aluminum hydroxide, magnesium hydroxide, zinc borate, barium metaborate, boron oxide, antimony trioxide, tin oxide, tin hydroxide, molybdenum oxide, ammonium molybdate, zirconium oxide, zirconium hydroxide and calcium aluminate; Preferably, the particle size of the inorganic additive flame retardant is no more than 10 μm.

9. A method for preparing a liquid molding epoxy resin according to any one of claims 1 to 8, characterized in that: The following steps are involved: The components are mixed in proportion to obtain the liquid molding epoxy resin.

10. Use of the liquid molding epoxy resin according to any one of claims 1 to 8 in manufacturing aviation composite materials.

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