A fluorinated epoxy resin with high hydroxyl content and its preparation method and application

Abstract

The invention discloses a fluorine-containing epoxy resin with a high hydroxyl content, and a preparation method and application thereof. The preparation method of the fluorine-containing epoxy resin with a high hydroxyl content comprises the following steps: reacting a base epoxy resin with a carboxyl-terminated liquid fluororubber to obtain a fluorine-containing epoxy resin prepolymer; reacting a diisocyanate with a hydroxyl-terminated liquid fluororubber to obtain an isocyanate-terminated polyurethane prepolymer; and uniformly mixing the fluorine-containing epoxy resin prepolymer, the isocyanate-terminated polyurethane prepolymer and a curing agent, and then curing to obtain a fluorine-containing epoxy resin with a high hydroxyl content. The fluorine-containing epoxy resin with a high hydroxyl content of the invention has good toughness, high swelling resistance to solvents such as anti-icing agents, and a wide range of applications.

Description

Technical Field

[0001] The invention relates to the technical field of modified epoxy resins, and in particular to a fluorine-containing epoxy resin with a high hydroxyl content, and a preparation method and application thereof. Background Art

[0002] Epoxy resin is an important type of thermosetting resin with strong cohesive force and dense material structure. Epoxy resin is widely used as anti-corrosion primer. Because its cured product has a three-dimensional network structure and is resistant to impregnation with oils, it is widely used in the inner wall lining of the integral fuel tank of oil tanks, cruise ships, and aircraft. However, epoxy resin is prone to cracking during the curing process, which makes its impact resistance, solvent resistance and heat resistance poor, and it is easy to swell, dissolve, crack or deform in solvents such as anti-icing agents. This limits its application in the fields of electronics, home appliances, automobiles, and aerospace to a certain extent. Therefore, it is necessary to modify the toughness and solvent resistance of epoxy resin so that the toughness and solvent resistance are improved without significantly affecting the mechanical properties of epoxy resin.

[0003] The toughening and solvent resistance modification of epoxy resin can be divided into four categories: (1) Improving the solvent resistance of the resin through chemical methods such as grafting, epoxidation, and halogenation; (2) Adding fluorinated rubber elastomers, acrylic rubber, chloroprene rubber, nitrile rubber, polytetrafluoroethylene powder, calcium carbonate, and hyperbranched polymers to toughen epoxy resin; (3) Introducing interpenetrating networks and increasing crosslinking density to improve the toughness of epoxy resin; (4) Studying toughening curing agents containing flexible segments to improve the flexibility of epoxy resin. Among all rubbers, fluororubber has the best solvent resistance, and liquid fluororubber is also often used for toughness modification. However, due to the large difference in the chemical structure of liquid fluororubber and epoxy resin, the compatibility between the two is poor and the interfacial bonding force is weak, resulting in poor toughening and solvent resistance effects.

[0004] Therefore, the preparation of high hydroxyl content fluorinated epoxy resin system is of great significance in improving solvent resistance and toughness. Summary of the invention

[0005] The purpose of the present invention is to overcome the above technical deficiencies, propose a high hydroxyl content fluorine-containing epoxy resin and its preparation method and application, and solve the technical problem in the prior art that the solvent resistance and toughness of liquid fluororubber-modified epoxy resin need to be improved.

[0006] In a first aspect, the present invention provides a method for preparing a fluorine-containing epoxy resin with a high hydroxyl content, comprising the following steps: The base epoxy resin and the carboxyl-terminated liquid fluororubber are reacted to obtain a fluorine-containing epoxy resin prepolymer; The diisocyanate and the terminal hydroxyl liquid fluororubber are reacted to obtain the terminal isocyanate polyurethane prepolymer; The fluorine-containing epoxy resin prepolymer, the terminal isocyanate polyurethane prepolymer and the curing agent are uniformly mixed and then cured to obtain the fluorine-containing epoxy resin with high hydroxyl content.

[0007] In a second aspect, the present invention provides a fluorinated epoxy resin with a high hydroxyl content, which is obtained by the preparation method of the fluorinated epoxy resin with a high hydroxyl content provided by the first aspect of the present invention.

[0008] In a third aspect, the present invention provides the use of the above-mentioned fluorine-containing epoxy resin with high hydroxyl content as a coating.

[0009] Compared with the prior art, the beneficial effects of the present invention include: The present invention toughens and modifies epoxy resin by introducing liquid fluororubber, and improves the solvent resistance of epoxy resin; by preparing a terminal isocyanate polyurethane prepolymer containing a flexible segment, the flexibility of epoxy resin is improved, and the coating has strong solvent resistance; through the cross-linking of hydroxyl and isocyanate, polyurethane and epoxy resin form semi-permeable network polymer and interpenetrating network polymer, which play a forced mutual dissolution and synergistic effect, thereby organically combining polyurethane with high elasticity and epoxy resin with good adhesion, and achieving better toughening effect through complementation and reinforcement. At the same time, the high hydroxyl content makes the polymer have high adhesion, and ether bonds can be further generated during the curing process, which has high cohesion and adhesion. The high hydroxyl content fluorine-containing epoxy resin of the present invention has good toughness, high swelling resistance to solvents such as anti-icing agents, and a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 (a) and (b) are respectively the anti-icing agent resistance test results of the high hydroxyl content fluorine-containing epoxy resin prepared in Example 1 of the present invention and the conventional epoxy resin prepared in Comparative Example 1. DETAILED DESCRIPTION

[0011] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0012] In a first aspect, the present invention provides a method for preparing a fluorine-containing epoxy resin with a high hydroxyl content, comprising the following steps: S1, reacting a base epoxy resin with a carboxyl-terminated liquid fluororubber to obtain a fluorine-containing epoxy resin prepolymer; S2, reacting diisocyanate and hydroxyl-terminated liquid fluororubber to obtain an isocyanate-terminated polyurethane prepolymer; S3, uniformly mixing the fluorine-containing epoxy resin prepolymer, the terminal isocyanate polyurethane prepolymer and the curing agent and then curing the mixture to obtain a fluorine-containing epoxy resin with a high hydroxyl content.

[0013] The present invention introduces liquid fluororubber to toughen and modify epoxy resin, and improves the solvent resistance of epoxy resin; prepares terminal isocyanate polyurethane prepolymer containing flexible segments, improves the flexibility of epoxy resin, and makes the coating have strong solvent resistance; through the cross-linking of hydroxyl and isocyanate, polyurethane and epoxy resin form semi-permeable network polymer (SIPN) and interpenetrating network polymer (IPN), which play a forced mutual dissolution and synergistic effect, thereby organically combining polyurethane with high elasticity and epoxy resin with good adhesion, and achieving better toughening effect through complementation and reinforcement. At the same time, the high hydroxyl content makes the polymer have high adhesion, and ether bonds can be further generated during the curing process, which has high cohesion and adhesion. The high hydroxyl content fluorine-containing epoxy resin of the present invention has good toughness, high swelling resistance to solvents such as anti-icing agents, and a wide range of applications. The prepolymer preparation method in the present invention is a one-step method, the process is simple and easy, no solvent needs to be added during the reaction, and it is safe and pollution-free.

[0014] In this embodiment, in step S1, the base epoxy resin is bisphenol A epoxy resin and / or bisphenol F epoxy resin, and the epoxy equivalent is 165 g / mol-185 g / mol.

[0015] In some specific embodiments of the present invention, the base epoxy resin is E51.

[0016] In this embodiment, in step S1, the carboxyl-terminated liquid fluororubber is at least one of C26-type carboxyl-terminated liquid fluororubber, C246-type carboxyl-terminated liquid fluororubber, and CM-type carboxyl-terminated liquid fluoroether rubber. Their structural formulas are as follows: .

[0017] In this embodiment, in step S1, the mass ratio of the base epoxy resin to the carboxyl-terminated liquid fluororubber is 100:(10-25). The present invention can make the modified epoxy resin have both strong weather resistance, solvent swelling resistance and good dispersibility by controlling the ratio of the two within the above range. If the amount of carboxyl-terminated liquid fluororubber added is too much, the epoxy resin will not be easily dispersed evenly and the viscosity will be too high. If the amount of carboxyl-terminated liquid fluororubber added is too little, the epoxy resin will have insufficient weather resistance and poor improvement in solvent swelling resistance.

[0018] In this embodiment, in step S1, the reaction temperature is 100-130° C., the reaction time is 2-5 hours, and the reaction is carried out under a protective atmosphere.

[0019] The present invention does not limit the type of protective atmosphere, and those skilled in the art can select it according to actual conditions. For example, the protective atmosphere can be nitrogen, etc.

[0020] In this embodiment, in step S2, the diisocyanate is at least one of hexamethylene diisocyanate, diphenylmethane diisocyanate, and isophorone diisocyanate.

[0021] In this embodiment, in step S2, the hydroxyl-terminated liquid fluororubber is at least one of C26 type hydroxyl-terminated liquid fluororubber and C246 type hydroxyl-terminated liquid fluororubber. Their structural formulas are as follows: .

[0022] In this embodiment, in step S2, the mass ratio of diisocyanate to terminal hydroxyl liquid fluororubber is 100: (10-25). The present invention can make the modified polyurethane have strong weather resistance, solvent swelling resistance and good dispersibility by controlling the ratio of the two within the above range. If the amount of terminal hydroxyl liquid fluororubber added is too much, it will cause the polyurethane to be difficult to disperse evenly and the viscosity is too high. If the amount of terminal hydroxyl liquid fluororubber added is too little, the polyurethane will have insufficient weather resistance and poor improvement in solvent swelling resistance.

[0023] In this embodiment, in step S2, polyether diol is added during the reaction of diisocyanate and hydroxyl-terminated liquid fluororubber. The present invention can not only reduce the viscosity of the polyurethane system by adding polyether diol, making it easier to process, but also adjust the hardness and flexibility of the polyurethane.

[0024] Furthermore, the polyether diol is at least one of polypropylene glycol and polybutylene glycol.

[0025] Furthermore, the molecular weight of the polyether diol is 500-4000.

[0026] Furthermore, the mass ratio of diisocyanate to polyether diol is 1:(0.4-0.6). The present invention controls the amount of polyether diol added within the above range, so that the synthesized polyurethane has a suitable ratio of flexible segments and rigid segments, and has good mechanical properties and flexibility. If the amount of polyether diol added is too much, the proportion of polyurethane flexible segments will increase, the overall flexibility will be enhanced, but the strength will be low. If the amount of polyether diol added is too little, the proportion of polyurethane hard segments will increase, thereby increasing cohesive energy and rigidity, and the mechanical strength will be enhanced, but the flexibility is insufficient.

[0027] In this embodiment, in step S2, a catalyst is added during the reaction of diisocyanate and hydroxyl-terminated liquid fluororubber.

[0028] Furthermore, the catalyst is at least one of dibutyltin dilaurate, stannous octoate, and stannous oleate.

[0029] Furthermore, the amount of the catalyst added is 0.5%-2% of the mass of the diisocyanate.

[0030] In this embodiment, in step S2, the reaction temperature is 70-90° C. and the reaction time is 2-5 h.

[0031] In this embodiment, in step S3, during the process of uniformly mixing the fluorinated epoxy resin prepolymer, the isocyanate-terminated polyurethane prepolymer and the curing agent, the molar ratio of hydroxyl to isocyanate in the fluorinated epoxy resin prepolymer and the isocyanate-terminated polyurethane prepolymer is controlled to be 1.1-1.2. The present invention can make the prepared fluorinated epoxy resin with high hydroxyl content have both strong mechanical properties and better flexibility by controlling the molar ratio of the two within the above range. If the proportion of isocyanate is too high, it will lead to an excessive proportion of hard segments, high brittleness and insufficient toughness; if the proportion of isocyanate is too low, it will lead to an excessive proportion of soft segments, and mechanical properties such as tensile strength and tear strength will not meet the standards.

[0032] In this embodiment, in step S3, the curing agent is at least one of polyetheramine D400, diaminodiphenyl sulfone, 2-ethyl-4-methylimidazole, triethylenetetramine, benzophenonetetracarboxylic dianhydride, DMP-30, triethanolamine, ethylene glycol ditrimellitate, and 703 curing agent (phenol, formaldehyde, ethylenediamine condensate).

[0033] In this embodiment, in step S3, the curing agent accounts for 20%-40% of the total mass of the fluorine-containing epoxy resin prepolymer and the isocyanate-terminated polyurethane prepolymer.

[0034] In this embodiment, in step S3, during the process of uniformly mixing the fluorine-containing epoxy resin prepolymer, the isocyanate-terminated polyurethane prepolymer and the curing agent, an auxiliary agent is also added. The present invention does not limit the type and amount of the auxiliary agent, and those skilled in the art can select according to actual conditions. For example, the auxiliary agent can be a promoter, an antioxidant, an anti-aging agent, a thixotropic agent, a defoaming agent, a dispersant, etc.

[0035] Furthermore, the accelerator is one or more of DMP-30, triethanolamine, DBU, and BMDA; the antioxidant is at least one of V920, AO80, and Y-310; the anti-aging agent is at least one of UV-944, UV-531, and B900; the thixotropic agent is at least one of FDSS-5, BYK-P 2710, and EP-7200H; the defoaming agent is at least one of BYK-a530, BYK-065, and SI 2722; and the dispersant is at least one of AKN-2070, AG-163, and KMT-3003.

[0036] In this embodiment, in step S3, the curing method is: first keep warm at 60°C-80°C for 1.5-2.5h, then heat to 85-95°C for 1-2h, and finally heat to 95-105°C for 1.5-2.5h.

[0037] In a second aspect, the present invention provides a fluorinated epoxy resin with a high hydroxyl content, which is obtained by the preparation method of the fluorinated epoxy resin with a high hydroxyl content provided by the first aspect of the present invention.

[0038] In a third aspect, the present invention provides the use of the above-mentioned fluorine-containing epoxy resin with high hydroxyl content as a coating.

[0039] To avoid redundancy, in the following embodiments of the present invention, C26 type carboxyl-terminated liquid fluororubber, C246 type carboxyl-terminated liquid fluororubber, CM type carboxyl-terminated liquid fluoroether rubber, C26 type hydroxyl-terminated liquid fluororubber, and C246 type hydroxyl-terminated liquid fluororubber are all from Zhejiang Nuotian Yixiang New Material Technology Co., Ltd.

[0040] Example 1 (1) Add 100g of epoxy resin E51 and 10g of carboxyl-terminated liquid fluororubber (C26 type carboxyl-terminated liquid fluororubber) into a 500ml three-necked flask, heat to 120°C while stirring under nitrogen protection, and react for 4h under nitrogen protection to obtain a fluorinated epoxy resin prepolymer. The fluorinated epoxy resin prepolymer was determined by infrared analysis at 1765cm -1 The characteristic infrared absorption peak of the carboxyl group disappears, indicating that almost all the carboxyl groups participate in the reaction, and finally a fluorinated epoxy resin prepolymer is obtained.

[0041] (2) Add 100 g of hexamethylene diisocyanate, 50 g of polyether diol (N210, relative molecular mass 1000), 1 g of dibutyltin dilaurate and 10 g of terminal hydroxyl liquid fluororubber (C26 type terminal hydroxyl liquid fluororubber) into a 500 ml three-necked flask, raise the temperature to 80 °C while stirring and react for 4 h to obtain a terminal isocyanate polyurethane prepolymer.

[0042] (3) Mix the fluorinated epoxy resin prepolymer and the terminal isocyanate polyurethane prepolymer, control the hydroxyl molar number: isocyanate molar number = 1.2, and add 703 curing agent (25% by weight), accelerator DMP-30 (2%), thixotropic agent BYK-P 2710 (5%), and anti-aging agent UV-944 (0.2%). Stir well again and perform vacuum degassing. Finally, inject the mixed resin (i.e., coating) into a mold preheated to 60°C, put it into an oven for programmed temperature curing and molding. The curing temperature is 60°C / 2h+90°C / 1.5h+100°C / 2h to obtain a fluorinated epoxy resin with a high hydroxyl content.

[0043] Example 2 The fluorine-containing epoxy resin prepolymer was prepared by a method substantially the same as that in Example 1, except that the amount of carboxyl-terminated liquid fluororubber (C26 type carboxyl-terminated liquid fluororubber) used was 15 g.

[0044] Example 3 The fluorine-containing epoxy resin prepolymer was prepared by a method substantially the same as that in Example 1, except that the amount of carboxyl-terminated liquid fluororubber (C26 type carboxyl-terminated liquid fluororubber) used was 20 g.

[0045] Example 4 The fluorine-containing epoxy resin prepolymer was prepared by a method substantially the same as that in Example 1, except that the amount of carboxyl-terminated liquid fluororubber (C26 type carboxyl-terminated liquid fluororubber) used was 25 g.

[0046] Example 5 The fluorine-containing epoxy resin prepolymer was prepared by a method substantially the same as that in Example 1, except that the carboxyl-terminated liquid fluororubber was C246 type carboxyl-terminated liquid fluororubber, and the amount used was 10 g.

[0047] Example 6 The fluorine-containing epoxy resin prepolymer was prepared by a method substantially the same as that in Example 1, except that the carboxyl-terminated liquid fluororubber was C246 type carboxyl-terminated liquid fluororubber, and the amount used was 15 g.

[0048] Example 7 The fluorine-containing epoxy resin prepolymer was prepared by a method substantially the same as that in Example 1, except that the carboxyl-terminated liquid fluororubber was C246 type carboxyl-terminated liquid fluororubber, and the amount used was 20 g.

[0049] Example 8 The fluorine-containing epoxy resin prepolymer was prepared by a method substantially the same as that in Example 1, except that the carboxyl-terminated liquid fluororubber was C246 type carboxyl-terminated liquid fluororubber, and the amount used was 25 g.

[0050] Example 9 The fluorine-containing epoxy resin prepolymer was prepared by a method substantially the same as that in Example 1, except that the carboxyl-terminated liquid fluororubber was a CM-type carboxyl-terminated liquid fluoroether rubber, and the amount used was 10 g.

[0051] Example 10 The fluorine-containing epoxy resin prepolymer was prepared by a method substantially the same as that in Example 1, except that the carboxyl-terminated liquid fluororubber was a CM-type carboxyl-terminated liquid fluoroether rubber, and the amount used was 15 g.

[0052] Embodiment 11 The fluorine-containing epoxy resin prepolymer was prepared by a method substantially the same as that in Example 1, except that the carboxyl-terminated liquid fluororubber was a CM-type carboxyl-terminated liquid fluoroether rubber, and the amount used was 20 g.

[0053] Example 12 The fluorine-containing epoxy resin prepolymer was prepared by a method substantially the same as that in Example 1, except that the carboxyl-terminated liquid fluororubber was a CM-type carboxyl-terminated liquid fluoroether rubber, and the amount used was 25 g.

[0054] Embodiment 13 The isocyanate-terminated polyurethane prepolymer was prepared in substantially the same manner as in Example 1, except that the amount of hydroxyl-terminated liquid fluororubber used was 15 g.

[0055] Embodiment 14 The isocyanate-terminated polyurethane prepolymer was prepared in substantially the same manner as in Example 1, except that the amount of hydroxyl-terminated liquid fluororubber used was 20 g.

[0056] Embodiment 15 The isocyanate-terminated polyurethane prepolymer was prepared in substantially the same manner as in Example 1, except that the amount of hydroxyl-terminated liquid fluororubber used was 25 g.

[0057] Example 16 The isocyanate-terminated polyurethane prepolymer was prepared by a method substantially the same as that in Example 1, except that the hydroxyl-terminated liquid fluororubber was C246 type hydroxyl-terminated liquid fluororubber, and the amount used was 10 g.

[0058] Embodiment 17 The isocyanate-terminated polyurethane prepolymer was prepared by a method substantially the same as that in Example 1, except that the hydroxyl-terminated liquid fluororubber was C246 type hydroxyl-terminated liquid fluororubber, and the amount used was 15 g.

[0059] Embodiment 18 The isocyanate-terminated polyurethane prepolymer was prepared by a method substantially the same as that in Example 1, except that the hydroxyl-terminated liquid fluororubber was C246 type hydroxyl-terminated liquid fluororubber, and the amount used was 20 g.

[0060] Embodiment 19 The isocyanate-terminated polyurethane prepolymer was prepared by a method substantially the same as that in Example 1, except that the hydroxyl-terminated liquid fluororubber was C246 type hydroxyl-terminated liquid fluororubber, and the amount used was 25 g.

[0061] Comparative Example 1 Epoxy resin E51 and hexamethylene diisocyanate were mixed, and 703 curing agent (30% of the total mass), accelerator DMP-30 (5%), thixotropic agent BYK-P 2710 (5%) and anti-aging agent UV-94 (0.1%) were added, and the mixture was stirred evenly again and vacuum degassed. Finally, the mixed resin (i.e., coating) was injected into a mold preheated to 60°C, and placed in an oven for programmed temperature rise curing and molding. The curing temperature was 60°C / 2h+90°C / 1.5h+100°C / 2h to obtain epoxy resin.

[0062] Performance Testing Solvent resistance test: Referring to SAE AMS-C-27725D-2016, an anti-icing agent water mixture was prepared according to the mass ratio of anti-icing agent (diethylene glycol methyl ether, DiEGME): water of 2:8, placed in a container, and heated to (74±3)°C; the high hydroxyl content fluorinated epoxy resin in Example 1 and the conventional fluorine-free epoxy resin coating in Comparative Example 1 were sprayed on a carbon steel plate and cured; different test pieces were suspended above the solution, and the test time was 60 days. The anti-icing agent resistance test results of the high hydroxyl content fluorinated epoxy resin in Example 1 and the conventional fluorine-free epoxy resin in Comparative Example 1 are as follows: Figure 1 shown.

[0063] pass Figure 1 It can be seen that compared with the conventional epoxy resin in Comparative Example 1, the coating formed by the fluorine-containing epoxy resin with a high hydroxyl content prepared in Example 1 of the present invention has better solvent resistance.

[0064] In summary, the present invention mixes and cures a fluorinated epoxy resin prepolymer, a terminal isocyanate polyurethane prepolymer and a curing agent to prepare a fluorinated epoxy resin with a high hydroxyl content. The resin system exhibits excellent swelling resistance to solvents such as anti-icing agents and has a wide range of applications.

[0065] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for preparing a fluorine-containing epoxy resin with a high hydroxyl content, characterized in that: The following steps are involved: The base epoxy resin and the carboxyl-terminated liquid fluororubber are reacted to obtain a fluorine-containing epoxy resin prepolymer; The diisocyanate and the terminal hydroxyl liquid fluororubber are reacted to obtain the terminal isocyanate polyurethane prepolymer; The fluorine-containing epoxy resin prepolymer, the isocyanate-terminated polyurethane prepolymer and the curing agent are uniformly mixed and then cured to obtain a fluorine-containing epoxy resin with a high hydroxyl content.

2. The method for preparing a fluorine-containing epoxy resin with a high hydroxyl content according to claim 1, characterized in that: The base epoxy resin is at least one of bisphenol A epoxy resin and bisphenol F epoxy resin, and the epoxy equivalent is 165g / mol-185g / mol; and / or, The carboxyl-terminated liquid fluororubber is at least one of C26-type carboxyl-terminated liquid fluororubber, C246-type carboxyl-terminated liquid fluororubber, and CM-type carboxyl-terminated liquid fluoroether rubber; and / or, The mass ratio of the base epoxy resin to the carboxyl-terminated liquid fluororubber is 100:(10-25); and / or, During the reaction of the base epoxy resin and the carboxyl-terminated liquid fluororubber, the reaction temperature is 100-130° C., the reaction time is 2-5 hours, and the reaction is carried out under a protective atmosphere.

3. The method for preparing a fluorine-containing epoxy resin with a high hydroxyl content according to claim 1, characterized in that: The diisocyanate is at least one of hexamethylene diisocyanate, diphenylmethane diisocyanate and isophorone diisocyanate; and / or, The hydroxyl-terminated liquid fluororubber is at least one of C26 type hydroxyl-terminated liquid fluororubber and C246 type hydroxyl-terminated liquid fluororubber; and / or, The mass ratio of the diisocyanate to the hydroxyl-terminated liquid fluororubber is 100:(10-25); and / or, During the reaction of the diisocyanate and the hydroxyl-terminated liquid fluororubber, the reaction temperature is 70-90° C. and the reaction time is 2-5 hours.

4. The method for preparing a fluorine-containing epoxy resin with a high hydroxyl content according to claim 1, characterized in that: During the reaction of the diisocyanate and the hydroxyl-terminated liquid fluororubber, polyether diol is also added; wherein, The polyether glycol is at least one of polypropylene glycol and polybutylene glycol; and / or, The molecular weight of the polyether glycol is 500-4000; and / or, The mass ratio of the diisocyanate to the polyether diol is 1:(0.4-0.6).

5. The method for preparing a fluorine-containing epoxy resin with a high hydroxyl content according to claim 1, characterized in that: During the reaction of the diisocyanate and the hydroxyl-terminated liquid fluororubber, a catalyst is also added; wherein, The catalyst is at least one of dibutyltin dilaurate, stannous octoate and stannous oleate; and / or, The added amount of the catalyst is 0.5%-2% of the mass of the diisocyanate.

6. The method for preparing a fluorine-containing epoxy resin with a high hydroxyl content according to claim 1, characterized in that: In the process of uniformly mixing the fluorine-containing epoxy resin prepolymer, the isocyanate-terminated polyurethane prepolymer and the curing agent, the molar ratio of hydroxyl group to isocyanate in the fluorine-containing epoxy resin prepolymer and the isocyanate-terminated polyurethane prepolymer is controlled to be 1.1-1.

2.

7. The method for preparing a fluorine-containing epoxy resin with a high hydroxyl content according to claim 1, characterized in that: The curing agent is at least one of polyetheramine D400, diaminodiphenyl sulfone, 2-ethyl-4-methyl-imidazole, triethylenetetramine, benzophenone tetracarboxylic dianhydride, DMP-30, triethanolamine, ethylene glycol ditrimellitate anhydride, and 703 curing agent; and / or, The curing agent accounts for 20%-40% of the total mass of the fluorine-containing epoxy resin prepolymer and the isocyanate-terminated polyurethane prepolymer; and / or, The curing method is: first keep the temperature at 60-80°C for 1.5-2.5h, then heat it to 85-95°C for 1-2h, and finally heat it to 95-105°C for 1.5-2.5h.

8. The method for preparing a fluorine-containing epoxy resin with a high hydroxyl content according to claim 1, characterized in that: In the process of uniformly mixing the fluorine-containing epoxy resin prepolymer, the isocyanate-terminated polyurethane prepolymer and the curing agent, an auxiliary agent is also added; wherein, The auxiliary agent is at least one of a accelerator, an antioxidant, an anti-aging agent, a thixotropic agent, a defoaming agent, and a dispersant.

9. A fluorine-containing epoxy resin with a high hydroxyl content, characterized in that: The high hydroxyl content fluorine-containing epoxy resin is obtained by the preparation method of the high hydroxyl content fluorine-containing epoxy resin according to any one of claims 1 to 8.

10. Use of the fluorine-containing epoxy resin with high hydroxyl content as claimed in claim 9 as a coating.

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