An ultra-thick solvent-free epoxy coating for offshore steel pipe piles, a preparation method and application thereof

Abstract

The application discloses a kind of offshore steel pipe pile with ultra-thick solventless epoxy coating and its preparation method and application, raw material includes A component and B component;With mass fraction calculation, A component includes: epoxy resin 20-25%, silicon branched modified epoxy resin 20-25%, active diluent 2-5%, calcium carbonate 10-20%, natural barium sulfate 10-20%, graphene 2-5%, glass flake 10-15%, silicon powder 5-10%, zinc phosphate 5-10%, thixotropic agent 0.8-2%, leveling agent 0.2-0.3%;B component includes: curing agent 15-30%, talc 15-25%, natural barium sulfate 15-25%, titanium white 10-15%, zinc phosphate 5-10%, leveling agent 0.2-0.3%.The present application can improve the adhesion of epoxy coating, salt resistance, wear resistance, aging resistance, can be used for the anticorrosive coating of offshore steel pipe pile near or contact seawater.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of coating technology, in particular to an ultra-thick solvent-free epoxy coating for offshore steel pipe piles and a preparation method thereof. BACKGROUND

[0002] Offshore steel pipe piles are made of high-strength steel and have good supporting and compression resistance. They are usually used as supports and fixings for wind turbine generators, platforms, and cross-sea bridges, etc. in the sea. When used in the sea, the large amount of chloride ion (Cl-) electrolyte in seawater acts as a conductive medium to cause electrochemical reactions on the surface of the steel pipe pile, corroding the steel. The metabolic activities of microorganisms, including sulfate-reducing bacteria and iron bacteria, in the marine environment change the chemical properties of the microenvironment around the steel pipe pile, accelerating the corrosion of the steel pipe pile. At the same time, the impact of waves and the friction of marine sediments can cause wear and tear on the surface of the steel pipe pile, accelerating corrosion.

[0003] Therefore, in order to ensure the long-term stability and durability of the steel pipe pile in the marine environment, the steel pipe pile needs to be subjected to necessary corrosion protection treatment. Common methods include coating anticorrosive paint, cathodic protection, and external coating materials, combined with the selection of pipe materials and the consideration of design allowance. Today, the combination of anticorrosive paint and cathodic protection is the most common corrosion protection strategy for offshore steel pipe piles. The coating efficiency of anticorrosive paint and the subsequent maintenance construction are relatively convenient. However, cathodic protection can cause the anticorrosive coating on the surface of the steel pipe pile to peel off.

[0004] With the increasing awareness of environmental protection, the research and development and application of marine anticorrosive coatings are increasingly focusing on environmental protection, low VOC, and low impact on the marine ecosystem. In terms of function, not only is strong corrosion resistance required, but also the trend is towards antifouling, wear resistance, low surface suitability, long weather resistance, and other capabilities. Moreover, the coating system and construction technology of anticorrosive coatings for offshore steel pipe piles need to be faster, more environmentally friendly, and lower in energy consumption. Therefore, anticorrosive coatings for offshore steel pipe piles need to develop in the direction of specialization, environmental protection, and high efficiency.

[0005] Currently, marine anticorrosive coatings are in long-term contact with seawater, and water molecules can penetrate the organic coating to reach the interface between the coating and the substrate. The water molecules replace the interaction between the coating and the substrate, causing the coating to lose adhesion, or the water molecules undergo electrochemical reactions with the steel at the interface between the two, causing the coating to lose its protective effect and accelerating the corrosion of the steel. SUMMARY

[0006] In view of the problems in the background art, the purpose of the present application is to provide an ultra-thick solvent-free epoxy coating for offshore steel pipe piles and a preparation method and application thereof. By adding a specific proportion of silicon branched modified epoxy resin, the adhesion, salt resistance, wear resistance, aging resistance, high temperature resistance, and mechanical strength of the epoxy coating can be improved, especially for seawater corrosion prevention.

[0007] To achieve the above object, the present application provides a kind of offshore steel pipe pile with ultra-thick solventless epoxy coating, raw material includes A component and B component;With mass fraction calculation, A component includes:

[0008]

[0009] B component includes:

[0010]

[0011] Optionally, the preparation method of the silicon branched modified epoxy resin includes the following steps: (1) in the inert gas protection reaction kettle with reflux device, add ethyl acetate, add butyl methacrylate at room temperature, glycidyl methacrylate, vinyl trimethoxysilane, control the temperature of reaction kettle 80-100 ℃, add initiator butyl acetate solution drop by drop under stirring state, keep reflux, reaction time is 2-4h, after cooling to room temperature, obtain pre-reaction liquid;(2) add 3-glycidyl ether oxypropyl trimethoxysilane in the pre-reaction liquid, stir evenly, add deionized water drop by drop under stirring state, control the temperature of reaction kettle in the range of 50-70 ℃, and the reaction time is 3-4h, continue to react at 100-110 ℃ for 3-5h;(3) remove reflux device, distill and remove solvent, deionized water washing, filtration, drying, to obtain silicon branched modified epoxy resin.

[0012] Optionally, the molar ratio of butyl methacrylate, glycidyl methacrylate, vinyl trimethoxysilane, 3-glycidyl ether oxypropyl trimethoxysilane is 1-2:3-5:1:1-2

[0013] Optionally, the curing agent is one or a combination of polyamide, polyether amine, alkyl phenolic amine and aliphatic polyamine.

[0014] Optionally, the active diluent is one or several of cyclohexane-1,2-dicarboxylic acid diglycidyl ester, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether and cyclohexane dimethanol diglycidyl ether.

[0015] Optionally, the epoxy resin is one or a combination of bisphenol A type epoxy resin, phenolic modified epoxy resin, bisphenol F type epoxy resin and acrylic modified epoxy resin.

[0016] Optionally, the initiator is one or a combination of azobisisobutyronitrile, dicumyl peroxide, sodium persulfate and ammonium persulfate.

[0017] Optionally, the thixotropic agent is one or a combination of polyamide wax, fumed silica and organic bentonite.

[0018] The application further provides a preparation method of the ultra-thick solvent-free epoxy coating for offshore steel pipe piles, comprising the following steps: (1) taking epoxy resin, silicon branched modified epoxy resin, active diluent, calcium carbonate, natural barium sulfate, graphene, glass flake, silicon powder, zinc phosphate, thixotropic agent and leveling agent according to weight fractions, heating to 50-70 DEG C in a reaction kettle, stirring at 2500-3500 revolutions / minute for 0.5-1 h, standing, vacuum degassing, discharging, to obtain a mixture A component; (2) taking curing agent, talcum powder, natural barium sulfate, titanium white, zinc phosphate and leveling agent according to weight fractions, heating to 40-50 DEG C in a reaction kettle, stirring at 2000-3000 revolutions / minute for 0.5 h, standing, vacuum degassing, discharging, to obtain a mixture B component; (3) mixing the mixture A component and the mixture B component uniformly at a mass ratio of 1:1 to obtain the ultra-thick solvent-free epoxy coating for offshore steel pipe piles.

[0019] The application further provides a use of the ultra-thick solvent-free epoxy coating for offshore steel pipe piles, which is used for the anticorrosive coating of offshore steel pipe piles close to or in contact with seawater.

[0020] The application further provides a use of the ultra-thick solvent-free epoxy coating for offshore steel pipe piles, which is also applicable to ship bodies, offshore survey platforms, oil extraction platforms, offshore oil and gas pipelines, port wharfs or sea-crossing bridges.

[0021] The application has the following beneficial effects:

[0022] 1. Firstly, butyl methacrylate, glycidyl methacrylate and vinyl trimethoxysilane are subjected to copolymerization to obtain a silicon-containing epoxy molecular chain grafted with alkoxy, and then under hydrolysis conditions, three alkoxy groups of the alkoxy silane and the alkoxy groups of 3-glycidyl ether oxypropyl trimethoxysilane are subjected to multidimensional hydrolysis grafting reaction, which not only increases the epoxy groups, but also forms a multidimensional grafting cross-linked silicon atom branched structure in the molecular structure. It is found that the silicon branched modified epoxy resin synthesized by the method is suitable for seawater corrosion prevention epoxy coating, and can significantly improve the adhesion, salt resistance, wear resistance, aging resistance, high temperature resistance and mechanical strength of the epoxy resin, and is especially suitable for seawater corrosion prevention.

[0023] 2. The mass ratio of the two components of the epoxy coating is 1:1, which is easy to measure and ensures the stability of construction, and is more suitable for automatic spraying construction.

[0024] 3. The epoxy coating has excellent corrosion resistance and can meet the relevant test requirements of System 7A in NORSOK M501, has good wear resistance and high hardness, and is suitable for use in the splash zone of offshore steel pipe piles.

[0025] 4. The product is non-toxic, meets the relevant requirements of "Hygienic Safety Evaluation Standard for Drinking Water Transmission and Distribution Equipment and Protective Materials" (2001), has no impact on the environment and does not affect the survival of marine organisms. The product is solvent-free, has good fineness, and the solid content can reach more than 99.5%, heavy metals are not detected, and meets the requirements of "GB30981-2020".

[0026] 5. Due to the performance improvement of the coating, the product can achieve a single film thickness of 3000pm, and the coating does not crack, meeting the requirement of more than 1000pm for offshore steel pipe piles, and improving the construction efficiency. DETAILED DESCRIPTION

[0027] In order to make the above-mentioned objectives, characteristics and advantages of the application more apparent and easy to understand, the specific embodiments of the application are described in detail below.

[0028] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the application, but the application can also be implemented in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the connotation of the application, therefore the application is not limited by the specific embodiments disclosed below.

[0029] According to the application, an ultra-thick solvent-free epoxy coating for offshore steel pipe piles is provided, raw materials of which include A component and B component; the A component includes, by mass fraction:

[0030]

[0031]

[0032] The B component includes:

[0033]

[0034] In an embodiment, the preparation method of the silicon branched modified epoxy resin includes the following steps: (1) adding ethyl acetate into a reaction kettle with a reflux device under inert gas protection, adding butyl methacrylate at room temperature, adding glycidyl methacrylate and vinyl trimethoxysilane, controlling the temperature of the reaction kettle at 80-100℃, adding a butyl acetate solution of initiator drop by drop under stirring, keeping reflux, and keeping the reaction time at 2-4h, and then cooling to room temperature to obtain a pre-reaction liquid; (2) adding 3-glycidyl ether oxypropyl trimethoxysilane into the pre-reaction liquid, stirring uniformly, adding deionized water drop by drop under stirring, controlling the temperature of the reaction kettle in the range of 50-70℃, and keeping the reaction time at 3-4h, and then continuing to react at 100-110℃ for 3-5h; (3) removing the reflux device, distilling and removing the solvent, washing with deionized water, filtering, and drying to obtain the silicon branched modified epoxy resin.

[0035] In an embodiment, the molar ratio of butyl methacrylate, glycidyl methacrylate, vinyl trimethoxysilane, 3-glycidyloxypropyl trimethoxysilane is 1-2:3-5:1:1-2.

[0036] In an embodiment, the curing agent is one or a combination of polyamide, polyether amine, alkyl phenol formaldehyde amine and aliphatic polyamine.

[0037] In an embodiment, the reactive diluent is one or more of cyclohexane-1,2-dicarboxylic acid diglycidyl ester, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, cyclohexane dimethanol diglycidyl ether.

[0038] In an embodiment, the epoxy resin is one or a combination of bisphenol A type epoxy resin, phenol formaldehyde modified epoxy resin, bisphenol F type epoxy resin and acrylic modified epoxy resin.

[0039] In an embodiment, the initiator is one or a combination of azobisisobutyronitrile, dicumyl peroxide, sodium persulfate, ammonium persulfate.

[0040] In an embodiment, the thixotropic agent is one or a combination of polyamide wax, fumed silica, organic bentonite.

[0041] The application also provides a preparation method of the ultra-thick solvent-free epoxy coating for offshore steel pipe piles, comprising the following steps: (1) weighing epoxy resin, silicon branched modified epoxy resin, reactive diluent, calcium carbonate, natural barium sulfate, graphene, glass flake, silicon powder, zinc phosphate, thixotropic agent and leveling agent according to the weight fraction, heating to 50-70℃ in a reaction kettle, stirring at 2500-3500 revolutions / minute for 0.5-1h, standing, vacuum degassing, discharging, to obtain a mixture A component; (2) weighing curing agent, talc, natural barium sulfate, titanium dioxide, zinc phosphate and leveling agent according to the weight fraction, heating to 40-50℃ in a reaction kettle, stirring at 2000-3000 revolutions / minute for 0.5h, standing, vacuum degassing, discharging, to obtain a mixture B component; (3) mixing the mixture A component and the mixture B component uniformly at a mass ratio of 1:1 to obtain the ultra-thick solvent-free epoxy coating for offshore steel pipe piles.

[0042] The application also provides a use of the ultra-thick solvent-free epoxy coating for offshore steel pipe piles, which is used for the anticorrosive coating of offshore steel pipe piles close to or in contact with seawater. The application can be applied to the solvent-free epoxy coating of the splash zone, tidal zone and underwater zone of offshore steel pipe piles. The coating can protect the steel pipe piles from electrochemical corrosion, accelerated corrosion by seawater and scouring force, and the corrosion influence of microorganisms, thereby ensuring long-term and safe use of the steel pipe piles. Meanwhile, the product can be sprayed once to form a film with a thickness of 3000 microns, which meets the thickness requirement of 1000 microns for the anticorrosion of the steel pipe piles, improves the construction efficiency, reduces energy consumption and emissions, and is more environmentally friendly. The application does not contain VOC and heavy metals, and has less influence on the marine environment.

[0043] The application also provides a use of the ultra-thick solvent-free epoxy coating for offshore steel pipe piles, which can also be applied to ship bodies, offshore survey platforms, oil extraction platforms, offshore oil and gas pipelines, port terminals or sea-crossing bridges.

[0044] The ultra-thick solvent-free epoxy coating for offshore steel pipe piles, the preparation method and application thereof are specifically described below by means of examples. The main raw materials and equipment used are as follows: in the absence of specific indications, the raw materials and equipment of the examples and comparative examples are the same; the materials without specific models or types are obtained from market purchase or common models available through common channels, and are not specifically limited.

[0045] Example 1

[0046] 1. Preparation of silicon branched modified epoxy resin

[0047] (1) In an inert gas protected reaction kettle with a reflux device, ethyl acetate was added, and then butyl methacrylate, glycidyl methacrylate and vinyl trimethoxysilane were added at room temperature. The temperature of the reaction kettle was controlled at 80℃, and a solution of azodiisobutyronitrile in butyl acetate was added dropwise under stirring. The reflux was maintained, the reaction time was 2h, and the pre-reaction liquid was obtained after cooling to room temperature;

[0048] (2) 3-glycidyl ether oxypropyl trimethoxysilane was added to the pre-reaction liquid and stirred uniformly. Deionized water was added dropwise under stirring, the temperature of the reaction kettle was controlled within 50℃, the reaction time was 3h, and the temperature was raised to 100℃ for continuous reaction for 3h. The molar ratio of butyl methacrylate, glycidyl methacrylate, vinyl trimethoxysilane and 3-glycidyl ether oxypropyl trimethoxysilane was 1:3:1:1;

[0049] (3) The reflux device was removed, the solvent was distilled and removed, the deionized water was washed, filtered and dried to obtain the silicon branched modified epoxy resin.

[0050] 2. Preparation of solvent-free epoxy coating

[0051] (1) Take 20 parts of acrylic modified epoxy resin, 20 parts of silicon branched modified epoxy resin, 2 parts of cyclohexane-1,2-dicarboxylic acid diglycidyl ester, 10 parts of calcium carbonate, 10 parts of natural barium sulfate, 2 parts of graphene, 10 parts of glass flake, 5 parts of silicon powder, 5 parts of zinc phosphate, 0.8 parts of fumed silica and 0.2 parts of leveling agent (BYK-348) by weight, heat to 50°C in a reaction kettle, stirring speed 2500 rpm, stirring for 0.5 h, standing, vacuum degassing, discharging, to get the mixture A component;

[0052] (2) Take 15 parts of polyether amine, 15 parts of talc, 15 parts of natural barium sulfate, 10 parts of titanium dioxide, 5 parts of zinc phosphate and 0.2 parts of leveling agent (BYK-348) by weight, heat to 40°C in a reaction kettle, stirring speed 2000 rpm, stirring for 0.5 h, standing, vacuum degassing, discharging, to get the mixture B component;

[0053] (3) Mix the above mixture A component and B component uniformly in a mass ratio of 1:1 to get a solvent-free epoxy coating.

[0054] Example 2

[0055] 1. Preparation of silicon branched modified epoxy resin

[0056] (1) In an inert gas protection reaction kettle with reflux device, add ethyl acetate, add butyl methacrylate at room temperature, add glycidyl methacrylate, vinyl trimethoxysilane, control the temperature of the reaction kettle at 100°C, add dropwise the solution of dicumyl peroxide in butyl acetate under stirring, keep reflux, reaction time is 4h, cool to room temperature, get the pre-reaction liquid;

[0057] (2) Add 3-glycidyl ether oxypropyl trimethoxysilane to the pre-reaction liquid and stir uniformly, add dropwise deionized water under stirring, control the temperature of the reaction kettle within 70°C, reaction time is 4h, continue to react at 110°C for 5h; The molar ratio of butyl methacrylate, glycidyl methacrylate, vinyl trimethoxysilane and 3-glycidyl ether oxypropyl trimethoxysilane is 2:5:1:2;

[0058] (3) Remove the reflux device, distill and remove the solvent, wash with deionized water, filter and dry to get the silicon branched modified epoxy resin.

[0059] 2. Preparation of solvent-free epoxy coating

[0060] (1) 25 parts of acrylic modified epoxy resin, 25 parts of silicon branched modified epoxy resin, 5 parts of neopentyl glycol diglycidyl ether, 20 parts of calcium carbonate, 20 parts of natural barium sulfate, 5 parts of graphene, 15 parts of glass flake, 10 parts of silicon powder, 10 parts of zinc phosphate, 2 parts of fumed silica and 0.3 parts of leveling agent (BYK-348) by weight were weighed, heated to 70°C in a reaction kettle, stirred at 3500 rpm for 1 h, vacuumed to remove bubbles, discharged, and a mixture A component was obtained;

[0061] (2) 30 parts of polyamide, 25 parts of talc, 25 parts of natural barium sulfate, 15 parts of titanium dioxide, 10 parts of zinc phosphate and 0.3 parts of leveling agent (BYK-348) by weight were weighed, heated to 50°C in a reaction kettle, stirred at 3000 rpm for 0.5 h, vacuumed to remove bubbles, discharged, and a mixture B component was obtained;

[0062] (3) The mixture A component and the mixture B component were mixed uniformly at a mass ratio of 1:1 to obtain a solvent-free epoxy coating.

[0063] Example 3

[0064] 1. Preparation of silicon branched modified epoxy resin

[0065] (1) Ethyl acetate was added to an inert gas protected reaction kettle with reflux device, and butyl methacrylate, glycidyl methacrylate and vinyl trimethoxysilane were added at room temperature. The temperature of the reaction kettle was controlled at 90°C, and the solution of dicumyl peroxide in butyl acetate was added dropwise under stirring. The reflux was maintained, the reaction time was 3 h, and the pre-reaction liquid was obtained after cooling to room temperature;

[0066] (2) 3-glycidyl ether oxypropyl trimethoxysilane was added to the pre-reaction liquid and stirred uniformly. Deionized water was added dropwise under stirring, the temperature of the reaction kettle was controlled within 60°C, the reaction time was 3.5 h, and the temperature was raised to 105°C for further reaction for 4 h. The molar ratio of butyl methacrylate, glycidyl methacrylate, vinyl trimethoxysilane and 3-glycidyl ether oxypropyl trimethoxysilane was 1.5:4:1:1.5;

[0067] (3) The reflux device was removed, the solvent was distilled and removed, deionized water was washed, filtered and dried to obtain the silicon branched modified epoxy resin.

[0068] 2. Preparation of solvent-free epoxy coating

[0069] (1) Take 22.5 parts of acrylic modified epoxy resin, 23 parts of silicon branched modified epoxy resin, 3.5 parts of trimethylolpropane triglycidyl ether, 15 parts of calcium carbonate, 15 parts of natural barium sulfate, 3.5 parts of graphene, 12 parts of glass flake, 8 parts of silicon powder, 7 parts of zinc phosphate, 1.5 parts of fumed silica and 0.25 parts of leveling agent (BYK-348) by weight, heat to 60°C in a reaction kettle, stirring speed 3000 rpm, stirring for 50 min, standing, vacuum degassing, discharging, to get the mixture A component;

[0070] (2) Take 18 parts of polyamide, 16 parts of talc, 17 parts of natural barium sulfate, 12 parts of titanium dioxide, 8 parts of zinc phosphate and 0.25 parts of leveling agent (BYK-348) by weight, heat to 45°C in a reaction kettle, stirring speed 2500 rpm, stirring for 0.5 h, standing, vacuum degassing, discharging, to get the mixture B component;

[0071] (3) Mix the above mixture A component and B component uniformly in a mass ratio of 1:1 to get a solvent-free epoxy coating.

[0072] Comparative Example 1

[0073] 1. Preparation of silicon branched modified epoxy resin

[0074] (1) In an inert gas protected reaction kettle with reflux device, add ethyl acetate, add butyl methacrylate at room temperature, add glycidyl methacrylate, vinyl trimethoxysilane, control the temperature of the reaction kettle at 90°C, add the initiator solution of butyl acetate drop by drop under stirring state, keep reflux, reaction time is 3h, cool to room temperature, get the pre-reaction liquid; the molar ratio of butyl methacrylate, glycidyl methacrylate, vinyl trimethoxysilane is 1.5:4:1;

[0075] (2) Remove the reflux device, distill and remove the solvent, wash with deionized water, filter, dry to get the silane modified epoxy resin.

[0076] 2. Preparation of solvent-free epoxy coating

[0077] Except that the silane modified epoxy resin is replaced by an equal amount of silicon branched modified epoxy resin, other is the same as example 3.

[0078] Comparative Example 2

[0079] Except that the silicon branched modified epoxy resin is not added, other is the same as example 3.

[0080] Performance test

[0081] The specific test standards and test data are shown in Table 1.

[0082] Table 1 test results

[0083]

[0084]

[0085]

[0086]

[0087] From the data of the examples and comparative examples, it can be seen that the present application makes epoxy grafting to the molecular chain containing alkoxy and silicon through copolymerization reaction, and then occurs multidimensional hydrolysis grafting reaction with the alkoxy of 3-glycidyloxypropyl trimethoxysilane, to obtain a silicon branched modified epoxy resin. When the silicon branched modified epoxy resin is added into a solvent-free epoxy coating, the adhesion, salt resistance, wear resistance, aging resistance, high temperature resistance and mechanical strength of the coating can be obviously improved, and the coating is especially suitable for the anticorrosion coating of offshore steel pipe piles.

[0088] The above examples are merely illustrative for the sake of clarity and are in no way intended to limit the scope of the embodiments. Other variations and modifications can be made to the above-described embodiments within the scope of the present application. Here, it is not necessary or possible to exhaust all the embodiments. The obvious variations and modifications derived therefrom are still within the scope of protection of the present application.

Claims

1. An ultra-thick type solvent-free epoxy coating for offshore steel pipe piles, characterized by, The raw materials include A component and B component; the A component includes, in terms of mass fraction: Epoxy resin 20-25% Silicon branched modified epoxy resin 20-25% Active diluent 2-5% Calcium carbonate 10-20% Natural barium sulfate 10-20% Graphene 2-5% Glass flake 10-15% Silicon powder 5-10% Zinc phosphate 5-10% Thixotropic agent 0.8-2% Leveling agent 0.2-0.3%; The B component includes: Curing agent 15-30% Talc 15-25% Natural barium sulfate 15-25% Titanium dioxide 10-15% Zinc phosphate 5-10% Leveling agent 0.2-0.3%; The preparation method of the silicon branched modified epoxy resin includes the following steps: (1) In the inert gas protection reaction kettle with reflux device, add ethyl acetate, add butyl methacrylate at room temperature, add glycidyl methacrylate, vinyl trimethoxysilane, control the temperature of the reaction kettle at 80-100℃, add the initiator butyl acetate solution drop by drop under stirring, keep reflux, the reaction time is 2-4h, cool to room temperature, get the pre-reaction liquid; (2) Add 3 glycidyl ether oxypropyl trimethoxysilane to the pre-reaction liquid, stir uniformly, add deionized water drop by drop under stirring, control the temperature of the reaction kettle in the range of 50-70℃, the reaction time is 3-4h, continue to react at 100-110℃ for 3-5h; (3) Remove the reflux device, distill and remove the solvent, wash with deionized water, filter, dry, get the silicon branched modified epoxy resin.

2. The ultra-thick type solvent-free epoxy coating for offshore steel pipe piles according to claim 1, characterized by, The molar ratio of butyl methacrylate, glycidyl methacrylate, vinyl trimethoxysilane, 3 glycidyl ether oxypropyl trimethoxysilane is 1-2:3-5:1:1-2.

3. The ultra-thick type solvent-free epoxy coating for offshore steel pipe piles according to claim 1, characterized by, The curing agent is one or combination of polyamide, polyether amine, alkyl phenolic amine and aliphatic polyamine.

4. The ultra-thick type solvent-free epoxy coating for offshore steel pipe piles according to claim 1, characterized by, The active diluent is one or several of cyclohexane-1,2-dicarboxylic acid diglycidyl ester, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, cyclohexane dimethanol diglycidyl ether.

5. The ultra-thick type solvent-free epoxy coating for offshore steel pipe piles according to claim 1, characterized by, The epoxy resin is one or combination of bisphenol A type epoxy resin, phenolic modified epoxy resin, bisphenol F type epoxy resin and acrylic modified epoxy resin.

6. The ultra-thick type solvent-free epoxy coating for offshore steel pipe piles according to claim 1, characterized by, The initiator is one or combination of azobisisobutyronitrile, dicumyl peroxide, sodium persulfate, ammonium persulfate.

7. The preparation method of the ultra-thick solvent-free epoxy coating for offshore steel pipe piles according to any one of claims 1-6, characterized in that, The method comprises the following steps: (1) taking epoxy resin, silicon branched modified epoxy resin, active diluent, calcium carbonate, natural barium sulfate, graphene, glass flake, silicon powder, zinc phosphate, thixotropic agent and leveling agent by weight fraction, heating to 50-70 DEG C in a reaction kettle, stirring at 2500-3500 r / min for 0.5-1 h, standing, vacuum degassing, discharging, to obtain a mixture A component; (2) taking curing agent, talc, natural barium sulfate, titanium dioxide, zinc phosphate and leveling agent by weight fraction, heating to 40-50 DEG C in a reaction kettle, stirring at 2000-3000 r / min for 0.5 h, standing, vacuum degassing, discharging, to obtain a mixture B component; (3) mixing the mixture A component and the mixture B component in a mass ratio of 1:1 to obtain an ultra-thick solvent-free epoxy coating for offshore steel pipe pile.

8. Use of the ultra-thick solvent-free epoxy coating for offshore steel pipe piles according to any one of claims 1 to 6 or the ultra-thick solvent-free epoxy coating for offshore steel pipe piles obtained by the production process according to claim 7, characterized in that, The anticorrosive coating is used for the offshore steel pipe pile near or in contact with seawater.

9. Use of the ultra-thick solvent-free epoxy coating for offshore steel pipe piles according to any one of claims 1 to 6 or the ultra-thick solvent-free epoxy coating for offshore steel pipe piles obtained by the production process according to claim 7, characterized in that, The anticorrosive coating is also used for ship body, offshore survey platform, oil extraction platform, offshore oil and gas pipeline, port wharf or cross-sea bridge.

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