Epoxy foam and method of making same

Abstract

The present application relates to a kind of epoxy foamed materials and its preparation method.The raw materials for preparing epoxy foamed material include the following components according to mass fraction:85-105 parts of first mixed component and 95-110 parts of second mixed component;Wherein, the first mixed component includes the following components according to mass fraction:80-90 parts of bisphenol A type epoxy resin, 1-1.5 parts of diisocyanate, 4-8 parts of polyether polyol, 0.1-1 parts of isocyanate silane coupling agent, 1-10 parts of active diluent and 3-5 parts of thermal expansion microspheres;Wherein, the second mixed component includes the following components according to mass fraction:95-100 parts of mercaptan curing agent and 0-5 parts of accelerator.The combination of these raw material components and the above-mentioned percentage range of each component is determined by a large number of experiments, and the above-mentioned combination and percentage range make the epoxy foamed material formed by the raw material components of the present application can be foamed rapidly at room temperature, which is beneficial to wide application.

Description

Technical Field

[0001] This invention relates to the field of foaming materials technology, and in particular to an epoxy foaming material and its preparation method. Background Technology

[0002] Currently, with the rapid development of various fields, the required materials are also evolving rapidly. Depending on the application of materials in different fields, there are greater challenges to their updating and replacement. Different usage environments have led to the emergence of different new materials. Foamed materials, as commonly used materials in most fields, are also facing challenges. Suitable foamed materials can be selected based on their application. Traditional foamed materials include polyurethane foamed materials and epoxy foamed materials, among others. Epoxy foaming methods include physical foaming and chemical foaming methods.

[0003] Traditional epoxy foaming methods involve heating epoxy resin, a latent curing agent, and a foaming agent at high temperatures to decompose the foaming agent and generate gas. This method requires heating and is not suitable for certain applications. Another method uses microspheres for foaming; similarly, this method also requires heating to achieve foaming. There are also epoxy foaming materials that can foam at room temperature, consisting of epoxy resin, aliphatic amine curing agents, and foaming agents. These foaming agents are typically low-viscosity polymethylhydrosiloxanes. While they can foam at room temperature, the working time is relatively long, and reaching 90% curing takes a considerable amount of time. They can also be rapidly cured by low-temperature heating, so this method also has limitations. Summary of the Invention

[0004] Therefore, it is necessary to provide an epoxy foaming material that can rapidly foam at room temperature and its preparation method.

[0005] An epoxy foam material, wherein the raw materials for preparing the epoxy foam material, by weight parts, comprise the following components:

[0006] The first mixed component is 85 to 105 parts; and

[0007] The second mixing component is 95 to 110 parts;

[0008] The first mixed component, by mass fraction, comprises the following components:

[0009]

[0010] The second mixture component, by mass fraction, comprises the following components:

[0011] 95 to 100 parts of thiol-based curing agent; and

[0012] Accelerator: 0 to 5 parts.

[0013] When preparing epoxy foam materials using the above-mentioned raw material components, polyether polyol, diisocyanate, isocyanate-based silane coupling agent, and bisphenol A type epoxy resin can react to obtain modified bisphenol A type epoxy resin. The modified bisphenol A type epoxy resin and thiol-based curing agent can react at room temperature, releasing heat to cause thermally expanded microspheres to foam, which then cures and solidifies after foaming. The combination of these raw material components and the above-mentioned percentage range of each component were determined through extensive experiments. The above-mentioned combination and percentage range enable the epoxy foam material formed by the raw material components of this invention to foam rapidly at room temperature, which is beneficial for its wide application.

[0014] In one feasible implementation, the average particle size of the thermally expandable microspheres is 10 μm to 35 μm.

[0015] In one feasible implementation, the thermally expandable microspheres comprise the following components according to their average particle size and mass fractions:

[0016] First thermal expansion microspheres, 10μm~20μm, 0.5 parts~2 parts;

[0017] Two to three portions of the second thermal expansion microspheres, 20μm to 35μm in size.

[0018] In one feasible implementation, the initial foaming temperature of the thermally expandable microspheres is 85℃~95℃, and the maximum foaming temperature of the thermally expandable microspheres is 115℃~130℃.

[0019] In one feasible implementation, the bisphenol A type epoxy resin is selected from at least one of E51 epoxy resin and E44 epoxy resin;

[0020] The diisocyanate is selected from at least one of TDI, MDI and IPDI;

[0021] The polyether polyol is selected from at least one of difunctional polyether polyols and trifunctional polyether polyols.

[0022] The isocyanate-based silane coupling agent is selected from at least one of 3-isocyanate-propyltrimethoxysilane and 3-isocyanate-propyltriethoxysilane.

[0023] In one feasible implementation, the reactive diluent is selected from at least one of diluent 660A, diluent AGE, diluent 748A, diluent 669, and diluent 692;

[0024] The accelerator is a tertiary amine accelerator.

[0025] A method for preparing any of the above-mentioned epoxy foam materials includes the following steps:

[0026] According to the mass fractions, bisphenol A type epoxy resin, diisocyanate, polyether polyol and isocyanate-based silane coupling agent are mixed evenly and reacted fully to obtain modified bisphenol A type epoxy resin.

[0027] The modified bisphenol A epoxy resin, reactive diluent, and thermally expanded microspheres are mixed evenly to obtain a first mixed component; and

[0028] The thiol curing agent and the accelerator are mixed evenly to obtain the second mixed component.

[0029] The preparation method of the epoxy foam material of the present invention is simple. Polyether polyol, diisocyanate, isocyanate-based silane coupling agent and bisphenol A type epoxy resin can react to obtain modified bisphenol A type epoxy resin. In subsequent use, the modified bisphenol A type epoxy resin and thiol curing agent can react at room temperature, releasing heat to cause thermal expansion microspheres to foam. After foaming, it is cured and formed, which is beneficial for wide application.

[0030] In one feasible implementation, the modified bisphenol A epoxy resin is prepared by the following steps:

[0031] The polyether polyol was dehydrated to obtain the dehydrated polyether polyol.

[0032] Diisocyanate and isocyanate-based silane coupling agent were mixed uniformly in a protective gas atmosphere. The mixture was heated to 80°C–85°C, and then the dehydrated polyether polyol was added. The reaction temperature was maintained at 80°C–85°C until the NCO% content remained within the range of 4%–5% and did not change further, thus obtaining an organosilicon-modified polyurethane intermediate.

[0033] The silicone-modified polyurethane intermediate was mixed evenly with bisphenol A type epoxy resin, and the reaction temperature was maintained at 80℃~85℃ for 3h~4h until the NCO% content dropped below 0.5% before discharge. The mixture was then sealed and cooled to room temperature to obtain modified bisphenol A type epoxy resin.

[0034] In one feasible implementation, the first mixed component is prepared by the following steps: the modified bisphenol A epoxy resin and the diluent are mixed evenly, then thermally expanded microspheres are added, the mixing temperature is maintained at no more than 40°C, the mixture is mixed evenly, and then vacuum degassing is performed while maintaining a pressure of -0.095MPa to -0.1MPa to obtain the first mixed component.

[0035] In one feasible implementation, the second mixed component is prepared by the following steps: mixing a thiol curing agent and an accelerator and degassing under vacuum, maintaining a pressure of -0.095 MPa to -0.1 MPa, maintaining a temperature not exceeding 40°C, and mixing for 0.5 h to 1 h to obtain the second mixed component. Attached Figure Description

[0036] Figure 1 This is a flowchart of a method for preparing an epoxy foam material according to an embodiment of the present invention. Detailed Implementation

[0037] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0039] According to one embodiment of the epoxy foam material, the raw materials for preparing the epoxy foam material, based on parts by mass, include the following components:

[0040] The first mixed component is 85 to 105 parts; and

[0041] The second mixing component is 95 to 110 parts;

[0042] The first mixed component, by mass fraction, includes the following components:

[0043]

[0044] The second mixture component, by mass fraction, includes the following components:

[0045] 95 to 100 parts of thiol-based curing agent; and

[0046] Accelerator: 0 to 5 parts.

[0047] Among the aforementioned raw materials, polyether polyol, diisocyanate, isocyanate-based silane coupling agent, and bisphenol A epoxy resin can react to obtain modified bisphenol A epoxy resin. The modified bisphenol A epoxy resin and thiol curing agent can react at room temperature, releasing heat to cause the thermally expanded microspheres to foam, which then cures and solidifies after foaming. Furthermore, modification of the bisphenol A epoxy resin can improve its toughness and impact resistance.

[0048] Among the above raw materials, the diluent is used to reduce the viscosity of the composition system, thereby improving the wetting and penetration of the product.

[0049] Among the above raw materials, the accelerator is used to promote the reaction between the thiol curing agent and the bisphenol A type epoxy resin, which is beneficial to improving the curing efficiency.

[0050] Based on the aforementioned embodiments, the average particle size of the thermally expandable microspheres is 10 μm to 35 μm. For example, the average particle size of the thermally expandable microspheres can be 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, or 35 μm.

[0051] Based on the aforementioned embodiments, the thermally expandable microspheres comprise the following components according to their average particle size and mass fractions:

[0052] First thermal expansion microspheres, 10μm~20μm, 0.5 parts~2 parts;

[0053] Two to three portions of the second thermal expansion microspheres, 20μm to 35μm in size.

[0054] The average particle size of the first thermally expandable microsphere can be, for example, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm or 20 μm, and the average particle size of the second thermally expandable microsphere can be, for example, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 31 μm, 32 μm, 33 μm, 34 μm or 35 μm. Modified bisphenol A epoxy resin and a thiol-based curing agent can react at room temperature, releasing heat to foam the first and second thermally expandable microspheres. By using two types of thermally expandable microspheres with different average particle sizes, and with the second type containing more microspheres than the first type, the smaller-diameter first microspheres can fill the voids in the larger-diameter second microspheres during foaming, promoting uniform foaming. Experimental results show that the epoxy foam material using the above-described method exhibits superior foam density and compressive strength.

[0055] Based on the aforementioned embodiments, the initial foaming temperature of the thermally expanded microspheres is 85℃~95℃, and the maximum foaming temperature of the thermally expanded microspheres is 115℃~130℃.

[0056] Based on the aforementioned embodiments, the bisphenol A type epoxy resin is selected from at least one of E51 epoxy resin and E44 epoxy resin.

[0057] Based on the aforementioned embodiments, the diisocyanate is selected from at least one of TDI, MDI and IPDI.

[0058] Based on the aforementioned embodiments, the polyether polyol is selected from at least one of difunctional polyether polyol and trifunctional polyether polyol.

[0059] Based on the aforementioned embodiments, the isocyanate-based silane coupling agent is selected from at least one of 3-isocyanate-propyltrimethoxysilane and 3-isocyanate-propyltriethoxysilane.

[0060] Based on the aforementioned embodiments, the active diluent is selected from at least one of 660A diluent, AGE diluent, 748A diluent, 669 diluent, and 692 diluent.

[0061] Based on the aforementioned embodiments, the accelerator is a tertiary amine accelerator.

[0062] When preparing epoxy foam materials using the above-mentioned raw material components, polyether polyol, diisocyanate, isocyanate-based silane coupling agent, and bisphenol A type epoxy resin can react to obtain modified bisphenol A type epoxy resin. The modified bisphenol A type epoxy resin and thiol-based curing agent can react at room temperature, releasing heat to cause thermally expanded microspheres to foam, which then cures and solidifies after foaming. The combination of these raw material components and the above-mentioned percentage range of each component were determined through extensive experiments. The above-mentioned combination and percentage range enable the epoxy foam material formed by the raw material components of this invention to foam rapidly at room temperature, which is beneficial for its wide application.

[0063] Please see Figure 1 One embodiment of the preparation method of epoxy foam material includes the following steps:

[0064] S10. According to the mass fractions, bisphenol A type epoxy resin, diisocyanate, polyether polyol and isocyanate-based silane coupling agent are mixed evenly and reacted fully to obtain modified bisphenol A type epoxy resin.

[0065] In one feasible implementation, the modified bisphenol A epoxy resin is prepared by the following steps:

[0066] S11. Dehydrate the polyether polyol to obtain the dehydrated polyether polyol.

[0067] In step S11, the dehydration of polyether polyol is performed as follows: the polyether polyol is added to a dry and impurity-free reactor, and the material is heated to 120°C while stirring. Then, a vacuum is drawn to -0.095MPa to -0.1MPa, and stirring is continued for 2 to 3 hours. The material is then discharged and placed in a drying room for later use.

[0068] S12. Mix diisocyanate and isocyanate-based silane coupling agent evenly in a protective gas atmosphere, heat to 80℃~85℃, then add dehydrated polyether polyol, maintain the reaction temperature at 80℃~85℃ until the NCO% content is in the range of 4%~5% and no longer changes, to obtain organosilicon modified polyurethane intermediate.

[0069] In particular, the ester bonds in organosilicon-modified polyurethane intermediates can undergo hydrolysis. By dehydrating the polyether polyol, the stability of organosilicon-modified polyurethane intermediates can be increased.

[0070] The protective gas can be nitrogen, etc.

[0071] In step S12, the equation for the reaction that generates the organosilicon-modified polyurethane intermediate is as follows:

[0072]

[0073] R1 represents a polyester group or a polyether group.

[0074] S13. Mix the silicone-modified polyurethane intermediate with bisphenol A epoxy resin evenly, maintain the reaction temperature at 80℃~85℃, maintain the reaction time at 3h~4h, until the NCO% content drops below 0.5% and discharge the material. Seal and cool to room temperature to obtain modified bisphenol A epoxy resin.

[0075] In step S13, the reaction equation between the silicone-modified polyurethane intermediate and the bisphenol A type epoxy resin is as follows:

[0076]

[0077]

[0078] S20. The modified bisphenol A epoxy resin, reactive diluent and thermally expanded microspheres obtained in step S10 are mixed evenly to obtain the first mixed component.

[0079] In one feasible implementation, the first mixed component is prepared by the following steps: the modified bisphenol A epoxy resin and the diluent are mixed evenly, then thermally expanded microspheres are added, the mixing temperature is maintained at no more than 40°C, the mixture is mixed evenly, and then vacuum degassing is performed while maintaining a pressure of -0.095MPa to -0.1MPa to obtain the first mixed component.

[0080] S30. Mix the thiol curing agent and accelerator evenly to obtain the second mixed component.

[0081] In one feasible implementation, the second mixed component is prepared by the following steps: mixing a thiol curing agent and an accelerator and degassing under vacuum, maintaining a pressure of -0.095 MPa to -0.1 MPa, maintaining a temperature not exceeding 40°C, and mixing for 0.5 h to 1 h to obtain the second mixed component.

[0082] It should be noted that after preparing the first mixed component and the second mixed component, the first mixed component and the second mixed component can be further mixed evenly and then foamed to obtain epoxy foam.

[0083] The preparation method of the epoxy foam material of the present invention is simple. Polyether polyol, diisocyanate, isocyanate-based silane coupling agent and bisphenol A type epoxy resin can react to obtain modified bisphenol A type epoxy resin. In subsequent use, the modified bisphenol A type epoxy resin and thiol curing agent can react at room temperature, releasing heat to cause thermal expansion microspheres to foam. After foaming, it is cured and formed, which is beneficial for wide application.

[0084] Referring to the above implementation details, in order to make the technical solution of this application more specific, clear and easy to understand, examples of the technical solution of this application are given below. However, it should be noted that the content to be protected by this application is not limited to the following embodiments 1 to 5.

[0085] The raw materials used in the following examples include: TDI 80 / 20, manufactured by Covestro; MDI-50, manufactured by Wanhua Chemical; polyether polyol 220, manufactured by Wanhua Chemical; polyether polyol 3010, manufactured by Lanxing Dongda; 3-isocyanate-propyltrimethoxysilane, manufactured by Hangzhou Jessica Chemical Co., Ltd.; 3-isocyanate-propyltriethoxysilane, manufactured by Hangzhou Jessica Chemical Co., Ltd.; E51 type epoxy resin, manufactured by Wuxi Sanmu Chemical; diluent 660A, manufactured by Anhui Xinyuan Chemical; diluent 748A, manufactured by Anhui Xinyuan Chemical; thermally expandable microspheres 120DU15, with an average particle size of 10μm to 20μm, manufactured by PolyChem Alloy; thermally expandable microspheres 120DU25, with an average particle size of 20μm to 30μm, manufactured by PolyChem Alloy. Alloy; Thiol curing agent R2020, manufactured by Guangzhou Ruichi Chemical; Thiol curing agent 5050, manufactured by Shenzhen Junqiao New Materials.

[0086] Examples 1 to 4

[0087] The preparation methods and foaming processes of the epoxy foam materials in Examples 1 to 4 are as follows:

[0088] (1) Preparation of modified bisphenol A type epoxy resin:

[0089] Weigh each raw material according to Table 1, add the polyether polyol to a dry and impurity-free reaction vessel, heat the material to 120°C while stirring, then vacuum stir for 2 hours, and discharge the dehydrated polyether polyol and put it in a drying room for later use.

[0090] Diisocyanate and isocyanate-based silane coupling agent are mixed evenly in a protective gas atmosphere, heated to 80°C, and then dehydrated polyether polyol is added. The reaction temperature is maintained at 80°C until the NCO% content is in the range of 4% to 5% and no longer changes, thus obtaining an organosilicon-modified polyurethane intermediate.

[0091] The silicone-modified polyurethane intermediate was mixed evenly with bisphenol A epoxy resin, the reaction temperature was maintained at 80℃, the reaction time was maintained at 3h, until the NCO% content dropped below 0.5% and the material was discharged. The mixture was then sealed and cooled to room temperature to obtain the modified bisphenol A epoxy resin.

[0092] (2) Preparation of the first mixed component:

[0093] The modified bisphenol A epoxy resin and diluent were mixed evenly, and then thermally expanded microspheres were added. The mixing temperature was maintained at 35°C. After mixing evenly, vacuum degassing was performed while maintaining a pressure of -0.1 MPa to obtain the first mixed component.

[0094] (3) Preparation of the second mixed component:

[0095] The thiol curing agent and accelerator were mixed and degassed under vacuum, maintaining a pressure of -0.1 MPa and a temperature of 35°C for 1 hour to obtain the second mixed component.

[0096] (4) Foaming:

[0097] Mix the first and second components evenly according to the ratio, remove the bubbles, pour into a mold and allow to foam freely at room temperature.

[0098] Table 1. Components and contents of epoxy foam materials in Examples 1-4 and Comparative Examples 1-3

[0099]

[0100]

[0101] In Table 1, " / " indicates that the item is empty or is 0.

[0102] Comparative Example 1

[0103] This comparative example is a comparative example of Example 1, providing an epoxy foam material and its preparation method and foaming process. The only difference between this and the epoxy foam material and its preparation method in Example 1 is that the curing agent is 593 curing agent. For specific components and parameters, please refer to Table 1.

[0104] Comparative Example 2

[0105] This comparative example is a comparative example of Example 1, providing an epoxy foam material and its preparation method and foaming process. The only difference between this and the epoxy foam material and its preparation method in Example 1 is that the foaming agent is 3.5g of polymethylhydrosiloxane (viscosity 20-25mpa.s). For specific components and parameters, please refer to Table 1.

[0106] Comparative Example 3

[0107] This comparative example is a comparative example of Example 1, providing an epoxy foam material and its preparation method and foaming process. The difference between this and the epoxy foam material and its preparation method in Example 1 is that unmodified bisphenol A epoxy resin is used. For specific components and parameters, please refer to Table 1.

[0108] Performance testing:

[0109] Samples were taken from the epoxy foam materials of Examples 1-4 and Comparative Examples 1-2 after free foaming for 24 hours. During the foaming process, the parameters in Table 2 were recorded. After the foaming was completed, the foaming density and compressive strength were tested. Five sets of tests were conducted for each data point, and the average value was taken.

[0110] Table 2. Performance test results of epoxy foam materials in Examples 1-4 and Comparative Examples 1-2

[0111]

[0112] In Table 2, " / " indicates that the item is not present.

[0113] As shown in Table 2, the foaming start time of the epoxy foam materials in Examples 1 to 4 is approximately 2 to 4 minutes, the foaming completion time is approximately 11 to 15 minutes, and the foaming density is greater than 400 g / cm³. 3 The compressive strength of all samples was greater than 20 MPa, indicating that the epoxy foam materials of Examples 1 to 4 can be rapidly foamed to a better foam density and compressive strength at room temperature. Comparing Example 1 with the epoxy foam materials of Comparative Examples 1 to 3, it can be seen that the epoxy foam material of Comparative Example 1 does not foam at room temperature, the epoxy foam material of Comparative Example 2 has a smaller foam density after foaming, and the epoxy foam material of Comparative Example 3 has a smaller compressive strength after foaming. This indicates that the epoxy foam material of Example 1 can be rapidly foamed at room temperature and has a better foam density and compressive strength after foaming.

[0114] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0115] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An epoxy foam material, characterized in that, The raw materials for preparing the epoxy foam material, by weight, include the following components: The first mixing component is 85 to 105 parts; and The second mixing component is 95 to 110 parts; The first mixed component, by mass fraction, comprises the following components: 80-90 parts of bisphenol A type epoxy resin; 1 to 1.5 parts of diisocyanate; 4 to 8 parts of polyether polyol; 0.1 to 1 part of isocyanate-based silane coupling agent; 1 to 10 parts of reactive diluent; and 3 to 5 parts of thermally expandable microspheres; The second mixture component, by mass fraction, comprises the following components: 95-100 parts of thiol-based curing agent; and Accelerator 0 to 5 parts; The average particle size of the thermally expandable microspheres is 10 μm to 35 μm; The initial foaming temperature of the thermally expandable microspheres is 85℃~95℃, and the maximum foaming temperature of the thermally expandable microspheres is 115℃~130℃. The epoxy foam material was prepared using the following method: According to the mass fractions, bisphenol A type epoxy resin, diisocyanate, polyether polyol and isocyanate-based silane coupling agent are mixed evenly and reacted fully to obtain modified bisphenol A type epoxy resin. The modified bisphenol A epoxy resin, reactive diluent, and thermally expanded microspheres are mixed evenly to obtain a first mixed component; and The thiol curing agent and an optional accelerator are mixed evenly to obtain the second mixed component; The modified bisphenol A epoxy resin is prepared using the following steps: The polyether polyol was dehydrated to obtain the dehydrated polyether polyol. Diisocyanate and isocyanate-based silane coupling agent were mixed uniformly in a protective gas atmosphere. After heating to 80°C~85°C, the dehydrated polyether polyol was added. The reaction temperature was maintained at 80°C~85°C until the NCO% content remained within the range of 4%~5% and no longer changed, yielding an organosilicon-modified polyurethane intermediate; and The silicone-modified polyurethane intermediate was mixed evenly with bisphenol A type epoxy resin, and the reaction temperature was maintained at 80℃~85℃ for 3h~4h until the NCO% content dropped below 0.5% before discharge. The mixture was then sealed and cooled to room temperature to obtain modified bisphenol A type epoxy resin.

2. The epoxy foam material according to claim 1, characterized in that, The thermally expandable microspheres comprise the following components according to their average particle size and mass fractions: First thermal expansion microspheres, 10μm~20μm, 0.5 parts~2 parts; Two to three portions of the second thermal expansion microspheres, ranging from 20 μm to 35 μm in size.

3. The epoxy foam material according to claim 1, characterized in that, The bisphenol A type epoxy resin is selected from at least one of E51 epoxy resin and E44 epoxy resin; The diisocyanate is selected from at least one of TDI, MDI and IPDI; The polyether polyol is selected from at least one of difunctional polyether polyols and trifunctional polyether polyols. The isocyanate-based silane coupling agent is selected from at least one of 3-isocyanate-propyltrimethoxysilane and 3-isocyanate-propyltriethoxysilane.

4. The epoxy foam material according to claim 1, characterized in that, The reactive diluent is selected from at least one of 660A diluent, AGE diluent, 748A diluent, 669 diluent, and 692 diluent; The accelerator is a tertiary amine accelerator.

5. A method for preparing an epoxy foam material according to any one of claims 1 to 4, characterized in that, Includes the following steps: According to the mass fractions, bisphenol A type epoxy resin, diisocyanate, polyether polyol and isocyanate-based silane coupling agent are mixed evenly and reacted fully to obtain modified bisphenol A type epoxy resin. The modified bisphenol A epoxy resin, reactive diluent, and thermally expanded microspheres are mixed evenly to obtain a first mixed component; and The thiol curing agent and an optional accelerator are mixed evenly to obtain the second mixed component; The modified bisphenol A epoxy resin was prepared using the following steps: The polyether polyol was dehydrated to obtain the dehydrated polyether polyol. Diisocyanate and isocyanate-based silane coupling agent were mixed uniformly in a protective gas atmosphere. After heating to 80°C~85°C, the dehydrated polyether polyol was added. The reaction temperature was maintained at 80°C~85°C until the NCO% content remained within the range of 4%~5% and no longer changed, yielding an organosilicon-modified polyurethane intermediate; and The silicone-modified polyurethane intermediate was mixed evenly with bisphenol A type epoxy resin, and the reaction temperature was maintained at 80℃~85℃ for 3h~4h until the NCO% content dropped below 0.5% before discharge. The mixture was then sealed and cooled to room temperature to obtain modified bisphenol A type epoxy resin.

6. The method for preparing epoxy foam material according to claim 5, characterized in that, The first mixed component was prepared by the following steps: the modified bisphenol A epoxy resin and diluent were mixed evenly, then thermally expanded microspheres were added, the mixing temperature was maintained at no more than 40°C, and after mixing evenly, vacuum degassing was performed, maintaining the pressure at -0.095MPa to -0.1MPa to obtain the first mixed component.

7. The method for preparing epoxy foam material according to claim 5, characterized in that, The second mixed component is prepared by the following steps: a thiol curing agent and an accelerator are mixed and degassed under vacuum, maintaining a pressure of -0.095MPa to -0.1MPa, a temperature of no more than 40℃, and a mixing time of 0.5h to 1h to obtain the second mixed component.

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