A special anti-corrosion coating for steel and its preparation method and application

Abstract

The present invention provides an anticorrosive coating for steel, a preparation method and application thereof, and belongs to the field of polymer rubber and plastic foaming. The anticorrosive coating of the present invention includes component A and component B, and the composition of component A includes: 10-20 parts of alicyclic epoxy resin, 10-25 parts of bisphenol A diglycidyl ether, 0.1-0.3 parts of modified reduced graphene oxide, 30-45 parts of modified zinc powder, 5-15 parts of filler, and 2-5 parts of auxiliary agent; the composition of component B includes: 1-1.5 parts of curing agent. The present invention improves the adhesion, impact resistance and adaptability to hot water of the anticorrosive coating by using alicyclic epoxy resin and bisphenol A diglycidyl ether in combination, and adding modified reduced graphene oxide and modified zinc powder at the same time, and also has the characteristics of saving resources and being green and environmentally friendly.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and in particular to an anti-corrosion coating specially used for steel materials, and a preparation method and application thereof. Background Art

[0002] In recent years, with the continuous development of new energy, geothermal energy as a clean and renewable energy has received widespread attention. Geothermal energy is a new clean energy with the advantages of large reserves, wide distribution, green and low-carbon, strong applicability and good stability. With the increasing awareness of environmental protection and the increasing shortage of energy, the rational development and utilization of geothermal resources has become more and more popular. Among them, the geothermal energy stored within 2,000 meters from the surface is 250 billion tons of standard coal. The national geothermal exploitable resources are 6.8 billion cubic meters per year, and the geothermal heat contained is 973 trillion kilojoules. In terms of the scale of geothermal utilization, my country has been ranked first in the world in recent years, and has been growing steadily at a rate of nearly 10% per year.

[0003] In the development of geothermal energy resources, in addition to geothermal power generation, the direct use of geothermal water for building heating, greenhouse agriculture, and hot spring tourism has also developed rapidly. However, the exploitation of geothermal energy requires a large number of geothermal water pipes to transport geothermal water, and the demand for water filter pipes, the main equipment for transporting geothermal water, is also increasing. The water filter pipe is a key component of the geothermal well. It is usually installed in the lower aquifer of the geothermal well pipe, mainly playing the role of wall protection and water filtering and sand blocking. There are many types of water filter pipes, and the commonly used ones are bridge-type water filter pipes, gravel-attached water filter pipes, and trapezoidal wire water filter pipes. Among them, the bridge-type water filter pipe is widely used due to its simple structure, low price, and light weight. However, this type of water filter pipe is made of punched and rolled steel plates, and the coating of the water filter pipe is prone to blistering and falling off, resulting in corrosion and damage to the water filter pipe. Summary of the invention

[0004] In order to solve the technical problems existing in the above-mentioned prior art, the present invention adopts the following technical solutions:

[0005] The present invention provides a special anti-corrosion coating for steel, comprising component A and component B.

[0006] The composition of component A includes: 10-20 parts of alicyclic epoxy resin, 10-25 parts of bisphenol A diglycidyl ether, 0.1-0.3 parts of modified reduced graphene oxide, 30-45 parts of modified zinc powder, 5-15 parts of filler, and 2-5 parts of additives;

[0007] The composition of the B component includes: 1-1.5 parts of curing agent.

[0008] Furthermore, the epoxy equivalent of the alicyclic epoxy resin is in the range of 180-255 g / eq, the viscosity at 25°C is in the range of 4000-6000 mPas, and the softening point is in the range of 80-120°C; the epoxy equivalent of the bisphenol A diglycidyl ether is in the range of 172-176 g / eqg / eq, the viscosity at 25°C is in the range of 4000-6000 mPas, and the softening point is in the range of 90-110°C.

[0009] Furthermore, the preparation process of the modified reduced graphene oxide includes: placing a silane coupling agent in an acidic system for hydrolysis, then placing the hydrolyzed silane coupling agent in an anhydrous ethanol dispersion of reduced graphene oxide, reacting at a temperature of 70-90°C for 5-9h, and after the reaction is completed, filtering, centrifuging and drying the reaction product in sequence to obtain modified reduced graphene oxide.

[0010] Furthermore, the pH of the acidic system is in the range of 2-5; the mass ratio of the hydrolyzed silane coupling agent to the anhydrous ethanol dispersion of reduced graphene oxide is 2-5:80-150.

[0011] Furthermore, the preparation process of the modified zinc sheet includes:

[0012] S1. Firstly, the zinc sheet is polished, then washed with alkaline degreasing liquid, rinsed with anhydrous ethanol and dried to obtain a pretreated zinc sheet for standby use;

[0013] S2. Add 1% by volume of a silane coupling agent to the solvent, stir at room temperature at a speed of 1200-3000 r / min for 10-45 min, then add 0.003 mol / L lanthanum nitrate, then add 0.05% by mass of a potassium hydroxide solution, adjust the pH of the system to about 9.5, stir evenly, and obtain a modifier;

[0014] S3, mixing the pretreated zinc sheet in step S1 and the modifier in step S2 in a mass ratio of 1:5-8, stirring evenly, and subjecting to modification treatment for 1-3 hours. After the modification treatment, centrifugation, anhydrous ethanol washing, filtering, drying and grinding are performed to obtain modified zinc sheets.

[0015] Furthermore, the filler includes at least one of mica powder, titanium dioxide, zinc oxide, zinc phosphate and calcium carbonate.

[0016] Furthermore, the auxiliary agent includes at least one of a thixotropic agent, a leveling agent, a reactive diluent, and an anti-settling agent.

[0017] Furthermore, the curing agent is cardanol-modified amine.

[0018] Furthermore, the solvent in step S2 is a mixture of distilled water and anhydrous ethanol in a volume ratio of 1:3-5.

[0019] The present invention provides a method for preparing the anti-corrosion coating specifically for steel, comprising the following steps:

[0020] First, the modified epoxy resin is placed in a reaction container. At a stirring speed of 1500-3000r / min, graphene oxide, modified zinc powder, fillers and additives are added in sequence according to the formula ratio. After stirring for 15-30 minutes, the mixture is ground and dispersed until the particle size is less than 60 microns. After standing and defoaming, a curing agent is added in proportion. After stirring evenly, the mixture is discharged to obtain a special anti-corrosion coating for steel.

[0021] The present invention also provides application of the anti-corrosion coating in the field of geothermal energy exploitation.

[0022] Compared with the prior art, the present invention has the following beneficial effects: the present invention improves the adhesion, impact resistance and adaptability to hot water of the anti-corrosion coating by combining alicyclic epoxy resin and bisphenol A diglycidyl ether and adding modified reduced graphene oxide and modified zinc powder, and also has the characteristics of saving resources and being green and environmentally friendly. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0024] The experimental methods or test methods described in the following examples are conventional methods unless otherwise specified; the raw materials and auxiliary agents are obtained from conventional commercial channels or prepared by conventional methods unless otherwise specified.

[0025] The alicyclic epoxy resin was purchased from Guangzhou Weilina Chemical Co., Ltd., with the specification parameters of EHPE3150CE, CAS: 244772-00-7;

[0026] Bisphenol A diglycidyl ether was purchased from Guangzhou Daixun Trading Co., Ltd., manufacturer Dow, CAS: 61788-97-4;

[0027] The preparation process of the modified reduced graphene oxide is as follows: adjusting the pH value of the silane coupling agent KH-570 to 4 with a 5wt% hydrochloric acid solution, hydrolyzing for 12 hours to obtain a KH-570 coupling agent hydrolyzate, then placing the KH-570 coupling agent hydrolyzate in an anhydrous ethanol dispersion of reduced graphene oxide at a mass ratio of 2:120, mixing evenly, reacting at a temperature of 80°C for 6 hours, and after the reaction is completed, filtering, centrifuging, and drying the reaction product in sequence to obtain the modified reduced graphene oxide.

[0028] The preparation process of the modified zinc sheet is as follows:

[0029] S1. First, use 180-mesh sandpaper to polish the zinc sheet, then use alkaline degreasing liquid to ultrasonically degrease for 15 minutes, centrifuge at 1200r / min for 5 minutes, rinse with anhydrous ethanol and dry to obtain the pretreated zinc sheet for later use;

[0030] S2. Add 1% by volume of silane coupling agent BTSPA to a solvent of distilled water and anhydrous ethanol, wherein the volume ratio of distilled water to anhydrous ethanol is 1:3, stir at a speed of 1200-3000 r / min for 10-45 min at room temperature, then add lanthanum nitrate with a concentration of 0.003 mol / L, and then add potassium hydroxide solution with a mass fraction of 0.05%, adjust the pH of the system to about 9.5, stir evenly, and obtain a modifier;

[0031] S3, mixing the pretreated zinc sheet in step S1 and the modifier in step S2 in a mass ratio of 1:8, stirring evenly, and performing modification treatment for 1-3 hours. After the modification treatment, centrifugation, anhydrous ethanol washing, filtering, drying and grinding are performed to obtain modified zinc sheets.

[0032] The method for preparing the anti-corrosion coating specially used for steel comprises the following steps:

[0033] First, alicyclic epoxy resin and bisphenol A diglycidyl ether are placed in a reaction container, and at a stirring speed of 1500-3000r / min, modified reduced graphene oxide, modified zinc powder, fillers and additives are added in sequence according to the formula ratio. After stirring for 15 minutes, grinding and dispersion are carried out until the particle size is less than 60 microns. After standing and defoaming, a curing agent is added in proportion, and after stirring evenly, the material is discharged to obtain a special anti-corrosion coating for steel.

[0034] The composition ratios of Examples 1-3 and Comparative Examples 1-3 are shown in Table 1 (the data in the table are parts by weight, in grams):

[0035] Table 1

[0036]

[0037] The fillers in Table 1 are mica powder, titanium dioxide and zinc oxide in a mass ratio of 1:1:0.5; the additives are thixotropic agent organic bentonite 881B, leveling agent BYK-300, active diluent and anti-settling agent CP-88.118 in a mass ratio of 1:1:1:0.2.

[0038] Performance Testing:

[0039] The prepared anti-corrosion coating was sprayed on the surface of a water filter pipe made of 316L stainless steel by air spraying with a spray thickness of 100-200 μm. The pipe was first baked at 90°C for 20 min, then heated to 190°C for 10 min, and finally heated to 200°C for 10 min. After complete curing, the pipe was taken out and cooled to obtain a test sample with a size of 50×50×2 mm.

[0040] The main chemical composition of the water filter tube made of 316L stainless steel is shown in Table 2:

[0041] Table 2

[0042] element content(%) C 0.080 Si 1.00 Mn 2.00 S 0.030 P 0.035 Cr 16.00 Ni 12.00 Mo 3.00

[0043] The specific operations are as follows:

[0044] After adding curing agent in proportion to the coatings prepared in Examples 1-3 and Comparative Examples 1-3, the coatings were sprayed on the surface of the water filter pipe and left at room temperature for 5 days to be tested for hot water resistance, impact resistance and adhesion.

[0045] The test methods and test results are shown in Table 3:

[0046] Table 3

[0047]

[0048] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A special anti-corrosion coating for steel, characterized in that: The invention comprises component A and component B, wherein component A comprises: 10-20 parts of alicyclic epoxy resin, 10-25 parts of bisphenol A diglycidyl ether, 0.1-0.3 parts of modified reduced graphene oxide, 30-45 parts of modified zinc flakes, 5-15 parts of fillers, and 2-5 parts of additives; and component B comprises: 1-1.5 parts of curing agent; The epoxy equivalent of the alicyclic epoxy resin is in the range of 180-255 g / eq, the viscosity at 25° C. is in the range of 4000-6000 mPas, and the softening point is in the range of 80-120° C.; the epoxy equivalent of the bisphenol A diglycidyl ether is in the range of 172-176 g / eqg / eq, the viscosity at 25° C. is in the range of 4000-6000 mPas, and the softening point is in the range of 90-110° C.; The preparation process of the modified reduced graphene oxide comprises: The silane coupling agent is placed in an acidic system for hydrolysis, and then the hydrolyzed silane coupling agent is placed in an anhydrous ethanol dispersion of reduced graphene oxide, and the reaction is carried out at a temperature of 70-90° C. for 5-9 hours. After the reaction is completed, the reaction product is filtered, centrifuged, and dried in sequence to obtain modified reduced graphene oxide; The pH of the acidic system is in the range of 2-5; the mass ratio of the hydrolyzed silane coupling agent to the anhydrous ethanol dispersion of reduced graphene oxide is 2-5:80-150; The preparation process of the modified zinc sheet comprises the following steps: S1. Firstly, the zinc sheet is polished, then washed with alkaline degreasing liquid, rinsed with anhydrous ethanol and dried to obtain a pretreated zinc sheet for standby use; S2. Add 1% by volume of a silane coupling agent to the solvent, stir at room temperature at a speed of 1200-3000 r / min for 10-45 min, then add 0.003 mol / L lanthanum nitrate, then add 0.05% by mass of a potassium hydroxide solution, adjust the pH of the system to about 9.5, stir evenly, and obtain a modifier; S3, mixing the pretreated zinc sheet in step S1 and the modifier in step S2 in a mass ratio of 1:5-8, stirring evenly, and subjecting to modification treatment for 1-3 hours. After the modification treatment, centrifugation, anhydrous ethanol washing, filtering, drying and grinding are performed to obtain modified zinc sheets.

2. The special anti-corrosion coating for steel according to claim 1, characterized in that: The filler includes at least one of mica powder, titanium dioxide, zinc oxide, zinc phosphate and calcium carbonate; the auxiliary agent includes at least one of a thixotropic agent, a leveling agent, an active diluent and an anti-settling agent.

3. The special anti-corrosion coating for steel according to claim 1, characterized in that: The curing agent is cardanol modified amine.

4. The special anti-corrosion coating for steel according to claim 1, characterized in that: The solvent in step S2 is a mixture of distilled water and anhydrous ethanol in a volume ratio of 1:3-5.

5. The method for preparing the special anti-corrosion coating for steel according to claim 1, characterized in that: The following steps are involved: First, the modified epoxy resin is placed in a reaction container. At a stirring speed of 1500-3000r / min, graphene oxide, modified zinc flakes, fillers and additives are added in sequence according to the formula ratio. After stirring for 15-30 minutes, the mixture is ground and dispersed until the particle size is less than 60 microns. After standing and defoaming, a curing agent is added in proportion. After stirring evenly, the mixture is discharged to obtain a special anti-corrosion coating for steel.

6. Application of the anti-corrosion coating according to any one of claims 1 to 4, or the anti-corrosion coating prepared by the method according to claim 5 in the field of geothermal energy extraction.

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