An epoxy resin composition having waterproofing properties and a method for preparing the same

Abstract

The application discloses an epoxy resin composition with waterproof performance and a preparation method thereof, and belongs to the technical field of epoxy resin modification. The preparation method comprises the following steps: mixing fluorine-containing modified polyurethane prepolymer, epoxy resin and an organic tin catalyst, heating to 80 DEG C-90 DEG C, and stirring to obtain fluorinated modified epoxy resin; mixing the fluorinated modified epoxy resin, a curing agent, a curing accelerator and a dihydrazide compound, heating to 60 DEG C-70 DEG C, and curing for 3h-5h to obtain the epoxy resin composition. The fluorine-containing modified polyurethane prepolymer obtained by modification is mixed with the epoxy resin to cross-link, and the obtained epoxy resin composition has good waterproof performance and mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of epoxy resin modification technology, specifically relating to an epoxy resin composition with waterproof properties and its preparation method. Background Technology

[0002] Epoxy resin is a type of synthetic resin with excellent physicochemical properties, mainly made by chemical reaction of epoxy compounds and curing agents. Its basic components include: (1) Epoxy resin matrix: Epoxy compounds: Common epoxy resins include bisphenol A, bisphenol F and epichlorohydrin. These epoxy compounds have good chemical stability and corrosion resistance, and are suitable for a variety of applications; (2) Curing agent: Curing agent is the key component in the curing process of epoxy resin. Commonly used curing agents include amines (such as aromatic amines and aliphatic amines), acid anhydrides, phenols, etc. The choice of curing agent directly affects the curing speed, mechanical properties and chemical resistance of epoxy resin; (3) Additives: In order to meet specific performance requirements, various additives are often added to epoxy resin, such as toughening agents, flame retardants, fillers, pigments, etc. These additives can improve the processing performance, mechanical properties and weather resistance of the resin.

[0003] Epoxy resins are widely used in various fields due to their excellent properties, primarily including construction and building materials (floor coatings, adhesives, etc.), electronics and electrical engineering (epoxy molding compounds for electronic component encapsulation), and industrial manufacturing (composite materials, protective coatings). The waterproofing properties of epoxy resins play a crucial role in these applications, protecting the substrate from corrosion and structural damage caused by moisture penetration, reducing maintenance and replacement costs, and thus extending the service life of epoxy resin products. Especially in the electronics and electrical engineering field, waterproofing effectively reduces electrical malfunctions caused by moisture.

[0004] Patent CN112521719A discloses a water-based epoxy resin cementitious slurry, its preparation method and application. This invention improves waterproof performance by directly adding a water-based solvent-free silane water-resistant agent with water-resistant properties, which is then mixed and compounded with epoxy resin and other materials.

[0005] Patent CN118956098A discloses a method for making waterproof density board from waste epoxy resin powder. This invention also improves waterproof performance by directly adding an organosilicon waterproofing agent and white oil with waterproof properties, and then mixing and compounding them with epoxy resin and other materials.

[0006] Silicone-based waterproofing agents are hydrophobic due to their low surface tension, preventing moisture intrusion. However, silicone-based waterproofing agents sometimes have poor interfacial bonding with epoxy resins, and the phase interface is prone to separation. Therefore, solubilizers or dispersants are needed to improve interfacial bonding. Excessive use can increase the brittleness of epoxy resins and easily lead to hydrolysis and failure in environments with strong alkalis or high temperatures.

[0007] Fluorinated organic compounds possess excellent low surface energy, strong waterproof performance, and superior resistance to acids, alkalis, and high temperatures. However, due to their extremely low surface activity and poor compatibility with substrates, they are prone to stress concentration points, leading to material cracking and damage, which hinders performance improvement. Therefore, utilizing fluorinated organic compounds to enhance the waterproof performance of epoxy resin materials is of great significance. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention involves mixing and crosslinking a modified fluorinated polyurethane prepolymer with an epoxy resin. The resulting epoxy resin composition exhibits excellent waterproof and mechanical properties, thereby solving the technical problems mentioned in the background art. Specifically, the technical solution of this invention includes the following:

[0009] An epoxy resin composition with waterproof properties, the epoxy resin composition comprising the following raw materials in parts by weight:

[0010] 3-6 parts by weight of fluorinated modified polyurethane prepolymer, 27-30 parts by weight of epoxy resin, 15-18 parts by weight of curing agent, 0.15-0.18 parts by weight of curing accelerator, 0.2-0.22 parts by weight of organotin catalyst and 0.1-0.2 parts by weight of dihydrazide compound.

[0011] Furthermore, the preparation method of the fluorinated modified polyurethane prepolymer includes the following steps:

[0012] Fluorinated organic compounds, diacetone acrylamide, enol compounds and initiators are mixed in a weight ratio of 4:2:4~5:0.08~0.1 and heated to 70℃~80℃ for 50min~60min to obtain fluorinated modified hydroxyl-terminated polybutadiene.

[0013] Fluorinated hydroxyl-terminated polybutadiene, diisocyanate, diethylene glycol and dihydroxybutyltin chloride are mixed in a weight ratio of 3~4:1.5~2:0.1~0.2:0.02~0.03 and heated to 80℃~90℃ for 2.5h~3h to obtain fluorinated modified polyurethane prepolymer.

[0014] Furthermore, the fluorinated organic compound includes perfluoropropyl vinyl ether or perfluoro3,6-dioxa-4-methyl-7-octenesulfonyl fluoride.

[0015] Furthermore, the enol compound includes 1,4-dihydroxy-2-butene, which needs to have a dihydroxy structure for condensation polymerization with diisocyanate.

[0016] Furthermore, the initiator includes azobisisobutyronitrile.

[0017] Furthermore, the diisocyanate includes hexamethylene diisocyanate.

[0018] Furthermore, the epoxy resin includes bisphenol A type epoxy resin E-44 or bisphenol A type epoxy resin E-51.

[0019] Furthermore, the curing agent is composed of methylhexahydrophthalic anhydride and polyamide 651 in a weight ratio of 2:1.

[0020] Furthermore, the curing accelerator includes DMP-30.

[0021] Furthermore, the organotin catalyst comprises monobutyltin oxide.

[0022] Furthermore, the dihydrazide compound includes succinic dihydrazide.

[0023] A method for preparing a waterproof epoxy resin composition, the method comprising the following steps:

[0024] Fluorinated modified polyurethane prepolymer, epoxy resin and organotin catalyst are mixed and heated to 80℃~90℃ and stirred to obtain fluorinated modified epoxy resin.

[0025] Fluorinated modified epoxy resin, curing agent, curing accelerator and diacylhydrazine compound are mixed and stirred and heated to 60℃~70℃ for 3h~5h to cure and obtain epoxy resin composition.

[0026] Furthermore, the conditions for the stirring reaction include a stirring speed of 800 r / min to 1000 r / min and a reaction time of 1 h to 1.5 h.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] This invention uses fluorinated organic compounds with low surface activity as the core component for improving epoxy resin materials. Due to the poor interfacial compatibility caused by the low surface energy and low surface activity of fluorinated organic compounds, direct addition for modification is ineffective. First, the fluorinated organic compound undergoes a carbon-carbon double bond polymerization reaction with diacetone acrylamide and an enol compound. Then, the fluorinated organic compound is introduced into hydroxyl-terminated polybutadiene. The enol compound 1,4-dihydroxy-2-butene has a dihydroxyl structure, allowing the hydroxyl-terminated polybutadiene to undergo condensation polymerization with diisocyanate and diethylene glycol, thereby introducing the fluorinated organic compound into the polyurethane structure, obtaining a fluorinated modified polyurethane prepolymer. This utilizes the good interfacial compatibility and reactivity between polyurethane and epoxy resin. By mixing and reacting the two, fluorinated organic compounds are introduced into the epoxy resin structure through chemical reaction. This effectively reduces the impact of poor interfacial compatibility caused by the low surface energy and low surface activity of fluorinated organic compounds, which can easily lead to poor mechanical properties of epoxy resin. Since the modified fluorinated polyurethane prepolymer introduces a fluorinated structure, it may reduce the efficiency of crosslinking with epoxy resin. However, by generating ketone-hydrazine crosslinks between diacetone acrylamide and diacylhydrazine compounds introduced into the fluorinated polyurethane prepolymer, the crosslinking efficiency between the fluorinated polyurethane prepolymer and epoxy resin is synergistically improved. This ensures that the prepared epoxy resin composition has good waterproof performance while also exhibiting good mechanical properties. Detailed Implementation

[0029] The technical solution of the present invention will be clearly and completely described below through embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Unless otherwise stated, all raw materials and reagents used in this invention are commercially available or can be prepared by known methods.

[0031] Preparation Example 1:

[0032] The preparation method of fluorine-modified polyurethane prepolymer specifically includes the following steps:

[0033] Four parts by weight of perfluoropropyl vinyl ether, two parts by weight of diacetone acrylamide, and four parts by weight of 1,4-dihydroxy-2-butene were weighed and added to a flask. Then, 15 parts by weight of ethyl acetate were added and stirred until evenly dispersed. Next, 0.08 parts by weight of azobisisobutyronitrile were added to the flask, and the mixture was stirred at 400 rpm. Nitrogen gas was then introduced to purge all air from the flask. The flask was then heated to 70°C and the reaction was timed to react for 50 minutes. After the reaction was completed, the ethyl acetate was removed by evaporation under reduced pressure, and the mixture was allowed to cool naturally to room temperature to obtain fluorinated hydroxyl-terminated polybutadiene.

[0034] Fluorinated hydroxyl-terminated polybutadiene and diethylene glycol were separately dehydrated under reduced pressure at 100°C and 4 mmHg for 30 min. Then, 3 parts by weight of fluorinated hydroxyl-terminated polybutadiene, 1.5 parts by weight of hexamethylene diisocyanate, 0.1 parts by weight of diethylene glycol, and 0.02 parts by weight of dihydroxybutyltin chloride were weighed and added to a reactor. Nitrogen gas was introduced into the reactor to purge air, and the reactor was heated to 80°C and reacted for 2.5 h. After the reaction, the mixture was allowed to cool naturally to room temperature to obtain a fluorinated modified polyurethane prepolymer.

[0035] Preparation Example 2:

[0036] The preparation method of fluorine-modified polyurethane prepolymer specifically includes the following steps:

[0037] Four parts by weight of perfluoropropyl vinyl ether, two parts by weight of diacetone acrylamide, and 4.5 parts by weight of 1,4-dihydroxy-2-butene were weighed and added to a flask. Then, 15 parts by weight of ethyl acetate were added and stirred until uniformly dispersed. Next, 0.09 parts by weight of azobisisobutyronitrile were added to the flask, and the mixture was stirred at 400 rpm. Nitrogen gas was then introduced to purge all air from the flask. The flask was then heated to 75°C and the reaction was timed to react for 55 minutes. After the reaction was completed, the ethyl acetate was removed by evaporation under reduced pressure, and the mixture was allowed to cool naturally to room temperature to obtain fluorinated modified hydroxyl-terminated polybutadiene.

[0038] Fluorinated hydroxyl-terminated polybutadiene and diethylene glycol were separately dehydrated under reduced pressure at 100°C and 4 mmHg for 30 min. Then, 3.5 parts by weight of fluorinated hydroxyl-terminated polybutadiene, 1.8 parts by weight of hexamethylene diisocyanate, 0.15 parts by weight of diethylene glycol, and 0.025 parts by weight of dihydroxybutyltin chloride were weighed and added to a reactor. Nitrogen gas was introduced into the reactor to purge air, and the reactor was heated to 85°C and reacted for 2.5 h. After the reaction, the mixture was allowed to cool naturally to room temperature to obtain a fluorinated modified polyurethane prepolymer.

[0039] Preparation Example 3:

[0040] The preparation method of fluorine-modified polyurethane prepolymer specifically includes the following steps:

[0041] Four parts by weight of perfluoro3,6-dioxa-4-methyl-7-octenesulfonyl fluoride, two parts by weight of diacetone acrylamide, and five parts by weight of 1,4-dihydroxy-2-butene were weighed and added to a flask. Then, 15 parts by weight of ethyl acetate were added and stirred until uniformly dispersed. Next, 0.1 parts by weight of azobisisobutyronitrile were added to the flask, and the mixture was stirred at 400 rpm. Nitrogen gas was then introduced to purge all air from the flask. The flask was then heated to 80°C and the reaction was timed to react for 60 min. After the reaction was completed, the ethyl acetate was removed by evaporation under reduced pressure, and the mixture was allowed to cool naturally to room temperature to obtain fluorinated hydroxyl-terminated polybutadiene.

[0042] Fluorinated hydroxyl-terminated polybutadiene and diethylene glycol were separately dehydrated under reduced pressure at 100°C and 4 mmHg for 30 min. Then, 4 parts by weight of fluorinated hydroxyl-terminated polybutadiene, 2 parts by weight of hexamethylene diisocyanate, 0.2 parts by weight of diethylene glycol, and 0.03 parts by weight of dihydroxybutyltin chloride were weighed and added to a reactor. Nitrogen gas was introduced into the reactor to purge air, and the reactor was heated to 90°C and reacted for 3 h. After the reaction, the mixture was allowed to cool naturally to room temperature to obtain a fluorinated modified polyurethane prepolymer.

[0043] Preparation Example 4:

[0044] The preparation method of fluorine-modified polyurethane prepolymer specifically includes the following steps:

[0045] Four parts by weight of a fluorinated organic compound, two parts by weight of diacetone acrylamide, and five parts by weight of 1,4-dihydroxy-2-butene were weighed and added to a flask. Then, 15 parts by weight of ethyl acetate were added and stirred until evenly dispersed. Next, 0.1 parts by weight of azobisisobutyronitrile were added to the flask, and stirring was maintained at 400 rpm. Nitrogen gas was then introduced to purge all air from the flask. The flask was then heated to 80°C and the reaction was timed to react for 90 min. After the reaction was completed, the ethyl acetate was removed by evaporation under reduced pressure, and the mixture was allowed to cool naturally to room temperature to obtain fluorinated modified hydroxyl-terminated polybutadiene.

[0046] The remaining preparation process is consistent with that of Preparation Example 3.

[0047] Preparation Example 5:

[0048] The preparation method of fluorine-modified polyurethane prepolymer specifically includes the following steps:

[0049] In Preparation Example 3, 1,4-dihydroxy-2-butene was replaced with 3-butenol, and the rest of the preparation process was the same as in Preparation Example 3.

[0050] Preparation Example 6:

[0051] The preparation method of fluorine-modified polyurethane prepolymer specifically includes the following steps:

[0052] In Preparation Example 3, hexamethylene diisocyanate was replaced with toluene diisocyanate, and the rest of the preparation process was the same as in Preparation Example 3.

[0053] Example 1:

[0054] A method for preparing a waterproof epoxy resin composition specifically includes the following steps:

[0055] The fluorinated modified polyurethane prepolymer and bisphenol A type epoxy resin E-44 obtained in Preparation Example 1 were subjected to vacuum degassing treatment at 50°C and -0.1 MPa until the bubbles were completely eliminated. Then, 3 parts by weight of the fluorinated modified polyurethane prepolymer and 27 parts by weight of the bisphenol A type epoxy resin E-44 were weighed, mixed, and heated to 80°C. Subsequently, 0.2 parts by weight of monobutyltin oxide were added, and the mixture was stirred at 800 r / min for 1 h to obtain a fluorinated modified epoxy resin. 15 parts by weight of curing agent (methylhexahydrophthalic anhydride and polyamide 651 in a weight ratio of 2:1), 0.15 parts by weight of curing accelerator DMP-30, and 0.1 parts by weight of succinic dihydrazide were added to the fluorinated modified epoxy resin. The mixture was then stirred at 500 r / min and heated to 60°C for 3 h to obtain an epoxy resin composition.

[0056] Example 2:

[0057] A method for preparing a waterproof epoxy resin composition specifically includes the following steps:

[0058] The fluorinated modified polyurethane prepolymer and bisphenol A type epoxy resin E-51 obtained in Preparation Example 2 were subjected to vacuum degassing treatment at 50°C and -0.1 MPa until the bubbles were completely eliminated. Then, 5 parts by weight of the fluorinated modified polyurethane prepolymer and 28 parts by weight of the bisphenol A type epoxy resin E-51 were weighed, mixed, and heated to 85°C. Subsequently, 0.21 parts by weight of monobutyltin oxide were added, and the mixture was stirred at 900 r / min for 1 h to obtain a fluorinated modified epoxy resin. 17 parts by weight of curing agent (methylhexahydrophthalic anhydride and polyamide 651 in a weight ratio of 2:1), 0.17 parts by weight of curing accelerator DMP-30, and 0.15 parts by weight of succinic dihydrazide were added to the fluorinated modified epoxy resin. The mixture was then stirred at 500 r / min and heated to 65°C for 4 h to obtain an epoxy resin composition.

[0059] Example 3:

[0060] A method for preparing a waterproof epoxy resin composition specifically includes the following steps:

[0061] The fluorinated modified polyurethane prepolymer and bisphenol A type epoxy resin E-51 obtained in Preparation Example 3 were subjected to vacuum degassing treatment at 50°C and -0.1 MPa until the bubbles were completely eliminated. Next, 6 parts by weight of the fluorinated modified polyurethane prepolymer and 30 parts by weight of the bisphenol A type epoxy resin E-51 were weighed, mixed, and heated to 90°C. Then, 0.22 parts by weight of monobutyltin oxide were added, and the mixture was stirred at 1000 r / min for 1.5 h to obtain a fluorinated modified epoxy resin. 18 parts by weight of curing agent (methylhexahydrophthalic anhydride and polyamide 651 in a weight ratio of 2:1), 0.18 parts by weight of curing accelerator DMP-30, and 0.2 parts by weight of succinic dihydrazide were added to the fluorinated modified epoxy resin. The mixture was then stirred at 500 r / min and heated to 70°C for 5 h to obtain an epoxy resin composition.

[0062] Comparative Example 1:

[0063] A method for preparing a waterproof epoxy resin composition specifically includes the following steps:

[0064] The fluorinated modified polyurethane prepolymer in Example 3 was replaced with the fluorinated modified polyurethane prepolymer obtained in Preparation Example 4, and the rest of the preparation process was the same as in Example 3.

[0065] Comparative Example 2:

[0066] A method for preparing a waterproof epoxy resin composition specifically includes the following steps:

[0067] The fluorinated modified polyurethane prepolymer in Example 3 was replaced with the fluorinated modified polyurethane prepolymer obtained in Preparation Example 5, and the rest of the preparation process was the same as in Example 3.

[0068] Comparative Example 3:

[0069] A method for preparing a waterproof epoxy resin composition specifically includes the following steps:

[0070] The fluorinated modified polyurethane prepolymer in Example 3 was replaced with the fluorinated modified polyurethane prepolymer obtained in Preparation Example 6, and the rest of the preparation process was the same as in Example 3.

[0071] Comparative Example 4:

[0072] A method for preparing a waterproof epoxy resin composition specifically includes the following steps:

[0073] In Example 3, the bisphenol A type epoxy resin E-51 was replaced with bisphenol A type epoxy resin E-12, and the rest of the preparation process remained the same as in Example 3.

[0074] Comparative Example 5:

[0075] A method for preparing a waterproof epoxy resin composition specifically includes the following steps:

[0076] The curing agent in Example 3 was replaced with methylhexahydrophthalic anhydride, and the rest of the preparation process remained the same as in Example 3.

[0077] Comparative Example 6:

[0078] A method for preparing a waterproof epoxy resin composition specifically includes the following steps:

[0079] The curing agent in Example 3 was replaced with m-phenylenediamine, and the rest of the preparation process was the same as in Example 3.

[0080] Comparative Example 7:

[0081] A method for preparing a waterproof epoxy resin composition specifically includes the following steps:

[0082] The curing agent in Example 3 was replaced with m-phenylenediamine, and the curing temperature was increased to 110°C. The rest of the preparation process was the same as in Example 3.

[0083] Comparative Example 8:

[0084] A method for preparing a waterproof epoxy resin composition specifically includes the following steps:

[0085] The monobutyltin oxide in Example 3 was replaced with dibutyltin dilaurate, and the rest of the preparation process was the same as in Example 3.

[0086] Comparative Example 9:

[0087] A method for preparing a waterproof epoxy resin composition specifically includes the following steps:

[0088] The succinic dihydrazide in Example 3 was replaced with adipate dihydrazide, and the rest of the preparation process was the same as in Example 3.

[0089] Comparative Example 10:

[0090] A method for preparing a waterproof epoxy resin composition specifically includes the following steps:

[0091] The succinic dihydrazide in Example 3 was removed and not added, while the rest of the preparation process remained the same as in Example 3.

[0092] The epoxy resin compositions prepared in Examples 1-3 and Comparative Examples 1-10 were subjected to tensile and flexural mechanical property tests using a universal testing machine. The test speed was 2 mm / min and the test temperature was 25 ± 1℃. The results are shown in Table 1 below.

[0093] Table 1 Mechanical Properties

[0094]

[0095] Weigh the epoxy resin compositions prepared in Examples 1-3 and Comparative Examples 1-10 before testing. Then, completely immerse the epoxy resin compositions prepared in Examples 1-3 and Comparative Examples 1-10 in purified water at 50°C for 24 hours. After immersion, remove them, wipe off the surface moisture with absorbent paper, and weigh them after testing. Calculate the water absorption rate based on the ratio of the mass difference before and after testing. The calculation formula is: Water absorption rate = (mass after testing - mass before testing) / mass before testing × 100%. The lower the water absorption rate, the better the waterproof performance. The test results are shown in Table 2 below.

[0096] Table 2 Waterproof performance

[0097]

[0098] Based on Tables 1 and 2 above, the following conclusions can be drawn:

[0099] (1) As can be seen from Examples 1 to 3, the epoxy resin composition prepared by the present invention not only has good waterproof performance, but also exhibits good mechanical properties.

[0100] (2) Comparative Example 1 shows that the waterproof and mechanical properties of the prepared epoxy resin composition are poor. This may be because the polymerization time of the fluorinated modified hydroxyl-terminated polybutadiene in this system is too long, which can easily lead to overpolymerization, making the fluorinated modified hydroxyl-terminated polybutadiene molecules too large, thereby weakening the condensation polymerization reactivity of the fluorinated modified hydroxyl-terminated polybutadiene and diisocyanate. This may be unfavorable for the preparation of fluorinated modified polyurethane prepolymer, and thus unfavorable for the modification of epoxy resin.

[0101] (3) Comparative Example 2 shows that the waterproof and mechanical properties of the prepared epoxy resin composition are poor. This may be because, although 3-butenol can react with diisocyanate through hydroxyl groups in this system, it is difficult to further polymerize to form a polyurethane structure due to the presence of only one hydroxyl group, which makes it difficult to form a fluorinated modified polyurethane prepolymer, thus hindering the modification of epoxy resin.

[0102] (4) Comparative Example 3 shows that the waterproof and mechanical properties of the prepared epoxy resin composition are poor. This may be because toluene diisocyanate contains a rigid planar benzene ring structure in this system. Although the benzene ring is beneficial to increase the waterproof performance, the epoxy resin itself already contains a lot of benzene ring structure when reacting with the epoxy resin. If benzene rings are further introduced into the fluorinated modified polyurethane prepolymer, the epoxy resin composition may become too brittle and prone to cracking due to excessive rigidity, which is not conducive to improving the waterproof and mechanical properties.

[0103] (5) Comparative Example 4 shows that the waterproof and mechanical properties of the prepared epoxy resin composition are poor. This may be because the epoxy value of the bisphenol A type epoxy resin E-12 in this system is low and the fluidity is poor, resulting in poor crosslinking efficiency with the fluorine-modified polyurethane prepolymer, which in turn leads to poor waterproof and mechanical properties of the prepared epoxy resin composition.

[0104] (6) Through comparative examples 5 to 7, it can be found that in this system, the selection of curing agent has a great influence on the mechanical properties of the final epoxy resin composition. The single curing agent has a poor thermal curing effect in this system. This may be because different curing agents have a large difference in curing performance at the curing temperature in this system. Further increasing the curing temperature may lead to excessively high brittleness and easy cracking due to local curing too fast and the degradation effect of high temperature on polyurethane, which in turn leads to poor mechanical properties of the prepared epoxy resin composition.

[0105] (7) Comparative Example 8 shows that the waterproof and mechanical properties of the prepared epoxy resin composition are poor. This may be because, although dibutyltin dilaurate also catalyzes the crosslinking reaction between fluorinated modified polyurethane prepolymer and epoxy resin in this system, the use of catalysts is subject to strict limitations in this system. Not all organotin catalysts can play a good catalytic role in this system.

[0106] (8) Comparative Example 9 shows that the choice of dihydrazide compound has a significant impact on the mechanical properties of the final epoxy resin composition. This may be because adipic acid dihydrazide has a longer carbon chain than succinic acid dihydrazide. If the carbon chain is too long, the epoxy resin composition will be too flexible, which will weaken the mechanical properties of the epoxy resin composition.

[0107] (9) Comparative Example 10 shows that in this system, the efficiency of the mixed crosslinking reaction between the fluorinated polyurethane prepolymer and the epoxy resin may be reduced due to the fluorinated structure on the fluorinated modified polyurethane prepolymer. If the succinic acid dihydrazide compound is not introduced to form ketone hydrazide crosslinking with the ketone group on the fluorinated modified polyurethane prepolymer, the waterproof performance and mechanical properties of the epoxy resin composition may be poor.

[0108] The embodiments described above provide a detailed explanation of the technical solutions and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. An epoxy resin composition with waterproof properties, characterized in that, The epoxy resin composition comprises the following raw materials in parts by weight: 3-6 parts by weight of fluorinated modified polyurethane prepolymer, 27-30 parts by weight of epoxy resin, 15-18 parts by weight of curing agent, 0.15-0.18 parts by weight of curing accelerator, 0.2-0.22 parts by weight of organotin catalyst and 0.1-0.2 parts by weight of dihydrazide compound; The preparation method of the fluorine-modified polyurethane prepolymer includes the following steps: Fluorinated organic compounds, diacetone acrylamide, enol compounds and initiators are mixed in a weight ratio of 4:2:4~5:0.08~0.1 and heated to 70℃~80℃ for 50min~60min to obtain fluorinated modified hydroxyl-terminated polybutadiene. Fluorinated modified hydroxyl-terminated polybutadiene, diisocyanate, diethylene glycol and dihydroxybutyltin chloride were mixed in a weight ratio of 3~4:1.5~2:0.1~0.2:0.02~0.03 and heated to 80℃~90℃ for 2.5h~3h to obtain a fluorinated modified polyurethane prepolymer. The fluorinated organic compounds include perfluoropropyl vinyl ether or perfluoro3,6-dioxa-4-methyl-7-octenyl sulfonyl fluoride; The enol compound includes 1,4-dihydroxy-2-butene; The diisocyanate includes hexamethylene diisocyanate; The epoxy resin includes bisphenol A type epoxy resin E-44 or bisphenol A type epoxy resin E-51; The curing agent is composed of methylhexahydrophthalic anhydride and polyamide 651 in a weight ratio of 2:1; The dihydrazide compound includes succinic dihydrazide.

2. The epoxy resin composition with waterproof properties according to claim 1, characterized in that, The curing accelerator includes DMP-30.

3. A method for preparing a waterproof epoxy resin composition as described in any one of claims 1 to 2, characterized in that, The preparation method includes the following steps: Fluorinated modified polyurethane prepolymer, epoxy resin and organotin catalyst are mixed and heated to 80℃~90℃ and stirred to obtain fluorinated modified epoxy resin. Fluorinated modified epoxy resin, curing agent, curing accelerator and diacylhydrazine compound are mixed, stirred and heated to 60℃~70℃ for 3h~5h to cure and obtain epoxy resin composition.

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