Epoxy graphene zinc-rich heavy anti-corrosion paint and preparation method thereof

Abstract

The invention relates to the technical field of anticorrosive paint, and particularly discloses a preparation method of epoxy graphene zinc-rich heavy-duty anticorrosive paint, which comprises the following steps: mixing graphene oxide and zinc powder, and cleaning with ultrapure water and ethanol in sequence; then mixing with ethanol, adding into a high-temperature and high-pressure reaction kettle, introducing nitrogen, reacting for 1-1.5 hours under the conditions that the pressure is 3-5MPa and the temperature is 244-260 DEG C, and cooling to room temperature to obtain a mixture B; stirring and mixing the mixture B, a silane coupling agent, a wetting dispersant and an organic solvent, performing ultrasonic treatment, adding epoxy resin, an anti-settling agent, the organic solvent, an epoxy reactive diluent and polysulfide rubber, and stirring to obtain the epoxy graphene zinc-rich heavy-duty anticorrosive paint. According to the preparation method of the epoxy graphene zinc-rich heavy anti-corrosion paint, the mixture of the graphene and the zinc powder is treated through the supercritical technology, uniform mixing of the graphene and the zinc powder can be achieved, the interaction between the graphene and the zinc powder can be enhanced, and the protection effect of the epoxy graphene zinc-rich heavy anti-corrosion paint is improved.

Description

Technical Field

[0001] The invention relates to the technical field of anti-corrosion coatings, and in particular to an epoxy graphene zinc-rich heavy anti-corrosion paint and a preparation method thereof. Background Art

[0002] In daily life, the corrosion of metal products has a great negative impact on their performance. Anti-corrosion coatings are a common anti-corrosion method for metal products. They can resist the corrosion of metal products in the use environment and extend the service life of metal products. Epoxy zinc-rich coatings are a widely used coating. They mainly achieve anti-corrosion effects in the following ways: With the help of the high content of zinc powder contained in epoxy zinc-rich coatings, the solid content of zinc powder is generally greater than 70%, forming a conductive network, sacrificing the anode (Zn) to protect the cathode (Fe). After the zinc powder is oxidized, it forms non-conductive ZnO and turns into a barrier anti-corrosion; the structure formed by fillers such as epoxy resin and zinc powder can block the intrusion of corrosive factors such as oxygen and moisture, and delay the corrosion process; but too much zinc powder will cause the coating to be porous, adhesion will decrease, and the cost will increase.

[0003] At present, a large number of researchers have added graphene to epoxy zinc-rich coating systems to improve their anti-corrosion properties. Graphene has the characteristics of high specific area, strong conductivity and lamellar structure, which can improve the cathodic protection ability and barrier effect of epoxy zinc-rich coatings. Patent application publication number CN 114133831 A discloses a graphene oxide waterborne epoxy coating and a preparation method thereof, wherein the coating is prepared by coating a graphene oxide waterborne epoxy coating, wherein the graphene oxide waterborne epoxy coating is obtained by mechanically stirring and dispersing a waterborne epoxy resin, a wetting agent, an anti-flash rust agent, a leveling agent, an anti-settling agent, mica powder, graphene oxide, a dispersant, and zinc powder. After adding graphene oxide, it can play a dual role of physical shielding anti-corrosion and electrochemical effect anti-corrosion, greatly improving the anti-corrosion effect. In the invention, zinc powder and graphene oxide are mixed by mechanical stirring, and the overall dispersibility is good, but the zinc powder is heavy and the graphene oxide is light. After mechanical mixing, there is still local aggregation and uneven dispersion, and the anti-corrosion effect of zinc powder and graphene oxide is not well exerted, which affects the anti-corrosion performance of the coating. In addition, the invention also needs to add an anti-flash rust agent. Patent application publication number CN 108690456 A discloses a water-based epoxy zinc-rich primer and a preparation method thereof. In addition to zinc powder and graphene oxide, the primer of the invention also needs to be added with ferrophosphorus powder and anti-flash rust agent anti-corrosion ingredients to obtain a better anti-corrosion effect. Summary of the invention

[0004] In view of the above shortcomings, the present invention provides an epoxy graphene zinc-rich heavy anti-corrosion paint and a preparation method thereof, which improves the anti-corrosion performance of the graphene zinc-rich anti-corrosion paint through the interaction between epoxy graphene and zinc, and reduces the amount of zinc powder. The specific technical scheme is as follows:

[0005] A method for preparing an epoxy graphene zinc-rich heavy anti-corrosion paint, wherein the heavy anti-corrosion paint is composed of the following raw materials by mass percentage: 7-15% epoxy resin, 24-32% zinc powder, 0.4-0.7% graphene oxide, 3-6% wetting dispersant, 0.1-0.3% silane coupling agent, 1.5-2.5% anti-settling agent, 45-54% organic solvent, 0.8-1.2% epoxy active diluent, 1.5-2.0% polysulfide rubber, and 4-6% epoxy resin curing agent; the preparation method comprises the following steps:

[0006] (1) mixing graphene oxide and zinc powder, washing with ultrapure water and ethanol in sequence, filtering, vacuum drying, and grinding to obtain a pretreated graphene oxide and zinc powder mixture A;

[0007] (2) mixing the pretreated graphene oxide and zinc powder mixture A obtained in step (1) with ethanol in a mass ratio of 1:8-20 to obtain a suspension, adding the suspension to a high-temperature and high-pressure reactor, introducing nitrogen, and then reacting at a pressure of 3-5 MPa and a temperature of 244-260° C. for 1-1.5 h, releasing the pressure, cooling to room temperature, taking out the product, and vacuum drying to obtain a mixture B;

[0008] (3) Mixing the mixture B obtained in step (2) with a silane coupling agent, a wetting dispersant and an organic solvent, stirring for the first time using a high-speed disperser, then ultrasonically treating, adding an epoxy resin, an anti-settling agent, an organic solvent, an epoxy reactive diluent and polysulfide rubber, and stirring for the second time using a high-speed disperser to obtain an epoxy graphene zinc-rich heavy anti-corrosion paint.

[0009] Preferably, in the above preparation method, the epoxy value of the epoxy resin is 175-195 g / eq; the metal zinc content in the zinc powder is ≥97%, and the average particle size D50 is 5-8 μm; the single-layer sheet diameter of the graphene oxide is 0.1-8 μm, the strippability is greater than 95%, and it has a carboxyl group; the amine value of the wetting dispersant is 9-12 mgKOH / g, and the molecular weight of the polysulfide rubber is 800-1200.

[0010] Preferably, in the above preparation method, the silane coupling agent is one or more of vinyl trimethoxysilane, γ-aminopropyl triethoxysilane, and γ-glycidyloxypropyl trimethoxysilane; the main component of the anti-settling agent is polyamide wax; the organic solvent is one or more of xylene, ethylene glycol butyl ether acetate, and n-butanol; the epoxy diluent is one or more of butyl glycidyl ether, allyl glycidyl ether, and ethylene glycol diglycidyl ether. The curing agent is one or more of triethylenetetramine, aniline, and ethylenediamine.

[0011] Preferably, in the above preparation method, in step (1), the specific steps of washing and filtering with ultrapure water and ethanol in sequence are: washing the mixture of graphene oxide and zinc powder with ultrapure water, filtering with filter paper, the pore size of the filter paper is in the range of 25nm-100nm; repeating the ultrapure water washing-filtering steps 2-5 times;

[0012] Then wash with anhydrous ethanol, stir with a high-speed disperser during the washing process, the speed of the high-speed disperser is 1000-2000rpm, the stirring time is 3-5min, filter is filtered with filter paper, the pore size of the filter paper is 25nm-100nm; repeat the anhydrous ethanol washing-filtration steps 1-3 times. Ethanol treatment is beneficial to the subsequent reaction in a high-temperature autoclave.

[0013] Preferably, in the above-mentioned preparation method, in the step (1), the vacuum drying process parameters are: heating temperature is 100-150° C., heating time is 5-8 h, and after grinding, the mixture is passed through a 400-600 mesh sieve.

[0014] Preferably, in the above-mentioned preparation method, in the step (2), the suspension is added to the high-temperature and high-pressure reactor, and the amount of the suspension added is 40-60% of the volume capacity of the high-temperature and high-pressure reactor.

[0015] Preferably, in the above-mentioned preparation method, in the step (2), the vacuum drying process parameters are: heating temperature is 100-150° C., and heating time is 1-3 h.

[0016] Preferably, in the above preparation method, the ultrasonic treatment has a treatment power of 1-2.5 W / ml, a heating temperature of 30-40° C., a frequency range of 30-50 kHz, and a treatment time of 20-40 min.

[0017] Preferably, in the above preparation method, in step (3), the stirring speed of the first stirring is 1000-1500 rpm, and the stirring time is 30-50 min; the stirring speed of the second stirring is 1500-2000 rpm, and the stirring time is 40-50 min.

[0018] An epoxy graphene zinc-rich heavy anti-corrosion paint, characterized in that the heavy anti-corrosion paint is prepared by the above-mentioned preparation method.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The preparation method of the epoxy graphene zinc-rich heavy anti-corrosion paint of the present invention treats the mixture of graphene and zinc powder by supercritical ethanol technology, which can not only achieve uniform mixing of the two, but also enhance the interaction between graphene and zinc powder, thereby improving the protective effect of the epoxy graphene zinc-rich heavy anti-corrosion paint.

[0021] 2. In the preparation method of the epoxy graphene zinc-rich heavy anti-corrosion paint of the present invention, supercritical ethanol is used to treat the graphene oxide with a carboxyl group and the zinc powder. On the one hand, the advantages of the supercritical fluid such as no gas-liquid interface, no surface tension and high solubility can be used to achieve uniform mixing of the two, and at the same time, the zinc powder is inserted between the epoxy graphite sheet structure to prevent re-aggregation; on the other hand, through the supercritical ethanol process, the surface of the zinc powder can have hydroxyl groups, which react with the graphene oxide with a carboxyl group in a high-temperature and high-pressure reactor to form a cross-network structure, so that the interaction between the zinc powder and the graphene oxide is stronger, which is beneficial to improving the comprehensive performance of the coating such as corrosion resistance and adhesion.

[0022] 3. The preparation method of the epoxy graphene zinc-rich heavy anti-corrosion paint of the present invention has a relatively simple preparation process, which is conducive to large-scale promotion. DETAILED DESCRIPTION

[0023] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments. Unless otherwise defined, all professional terms used hereinafter have the same meaning as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present invention. Unless otherwise specifically stated, various raw materials, reagents, instruments and equipment used in the present invention, etc. can be purchased from the market or can be prepared by existing methods.

[0024] Example 1

[0025] An epoxy graphene zinc-rich heavy anticorrosive paint is composed of the following raw materials: 8g of epoxy resin, 27g of zinc powder, 0.6g of graphene oxide, 3g of wetting dispersant, 0.1g of silane coupling agent, 1.5g of anti-settling agent, 53g of organic solvent, 0.8g of epoxy reactive diluent, 1.5g of polysulfide rubber, and 4g of epoxy resin curing agent. The epoxy value of the epoxy resin is 185g / eq, the metal zinc content of the zinc powder is 98%, the average particle size D50 is 3μm, the single-layer sheet diameter of the graphene oxide is 0.1-5μm, the stripping rate is greater than 95%, and it has a carboxyl group and a hydroxyl content of 6%; the silane coupling agent is acetyltrimethoxysilane, the number average molecular weight of the polysulfide rubber is 956, and the amine value of the epoxy resin curing agent is 33mgKOH / g. The amine value of the wetting and dispersing agent is 10 mgKOH / g, the organic solvent is n-butanol, the epoxy reactive diluent is butyl glycidyl ether, and the epoxy resin curing agent is ethylenediamine.

[0026] This embodiment also provides a method for preparing epoxy graphene zinc-rich heavy anti-corrosion paint, comprising the following steps:

[0027] (1) pouring graphene oxide into zinc powder and mixing directly to obtain a mixture, washing the graphene oxide and zinc powder mixture with ultrapure water, and then filtering with filter paper with a pore size of 25 nm, and repeating the washing-filtering operation twice;

[0028] The mixture cake treated with ultrapure water was washed with anhydrous ethanol. During the washing process, a high-speed disperser was used for stirring. The speed of the high-speed disperser was 1600 rpm and the stirring time was 5 min. Then, filter paper was used for filtration. The pore size of the filter paper was 25 nm. The ethanol washing-filtration operation was repeated once.

[0029] The mixture cake of graphene oxide and zinc powder was placed in a vacuum oven, heated at 128° C. for 5 h, and ground. The ground powder was passed through a 400-mesh sieve to obtain a pretreated mixture A of graphene oxide and zinc powder, which was stored in a vacuum oven for later use.

[0030] (2) Mixture A and anhydrous ethanol are mixed in a ratio of 1:8. After mixing, the mixture is added to a high-temperature high-pressure reactor in an amount of 40% of the volume capacity of the high-temperature high-pressure reactor. Nitrogen is introduced and the ventilation is stopped after 5 minutes. The high-temperature high-pressure reactor is sealed and the temperature in the high-temperature high-pressure reactor is gradually increased to 249° C. The constant temperature time is 1.5 h and the pressure is controlled at 3.6 MPa. At this time, the ethanol fluid in the high-temperature high-pressure reactor is in a supercritical state. After the reaction is completed, the valve of the high-temperature high-pressure reactor is opened to release the pressure, and the temperature of the high-temperature high-pressure reactor is lowered to room temperature. The product is taken out and placed in a vacuum oven at a heating temperature of 128° C. for 1 h to obtain mixture B.

[0031] (3) Mixing the mixture B obtained in step (2) with a silane coupling agent, a wetting dispersant and 10 wt.% of an organic solvent, and stirring the mixture using a high-speed disperser at a stirring speed of 1600 rpm for 30 min; after the stirring, treating the stirred product using an ultrasonic device at a treatment power of 2.5 W / ml, a heating temperature of 30° C., a frequency range of 30 kHz, and a treatment time of 30 min;

[0032] Continue to add epoxy resin, anti-settling agent, the remaining 90wt.% organic solvent, epoxy reactive diluent and polysulfide rubber, and use a high-speed disperser to stir at a stirring speed of 2000rpm for 40min; after the treatment, epoxy graphene zinc-rich heavy anti-corrosion paint can be obtained, and epoxy resin curing agent is added before use.

[0033] Comparative Example 1

[0034] The difference between this comparative example and Example 1 is that in step (2), graphene and zinc powder are separately subjected to supercritical treatment, and then in step (3), the graphene supercritical product and the zinc powder supercritical product are mixed with a silane coupling agent, a wetting dispersant and 10% of an organic solvent. The other steps and parameters are the same as those in Example 1, and the raw material composition of the epoxy graphene zinc-rich heavy anti-corrosion paint is the same as that in Example 1.

[0035] Comparative Example 2

[0036] The difference between this comparative example and Example 1 is that in step (2) of the preparation method, deionized water is used instead of anhydrous ethanol, nitrogen is introduced, ventilation is stopped after 5 minutes, the high-temperature and high-pressure reactor is closed, the temperature in the high-temperature and high-pressure reactor is gradually increased to 374°C, the constant temperature time is 1.5 hours, and the pressure is controlled at 22.1 MPa. At this time, the water fluid in the high-temperature and high-pressure reactor is in a supercritical state, and the other steps and parameters are the same as those in Example 1. The raw material composition of the epoxy graphene zinc-rich heavy anti-corrosion paint is the same as that in Example 1.

[0037] Comparative Example 3

[0038] The difference between this comparative example and Example 1 is that the preparation method is different, and specifically comprises the following steps:

[0039] (1) directly mixing graphene oxide and zinc powder to obtain a mixture, washing the graphene oxide and zinc powder mixture with ultrapure water, and then filtering with filter paper with a pore size of 25 nm, and repeating the washing-filtering operation twice;

[0040] The mixture cake treated with ultrapure water was washed with anhydrous ethanol. During the washing process, a high-speed disperser was used for stirring. The speed of the high-speed disperser was 1600 rpm and the stirring time was 5 min. Then, filter paper was used for filtration. The pore size of the filter paper was 25 nm. The ethanol washing-filtration operation was repeated once.

[0041] The mixture cake of graphene oxide and zinc powder was placed in a vacuum oven, heated at 128° C. for 5 h, and ground. The ground powder was passed through a 400-mesh sieve to obtain a pretreated mixture A of graphene oxide and zinc powder, which was stored in a vacuum oven for later use.

[0042] (2) Mixing the mixture A obtained in step (3) with a silane coupling agent, a wetting dispersant and 10 wt.% of an organic solvent, and stirring the mixture using a high-speed disperser at a stirring speed of 1600 rpm for 30 min; after the stirring, treating the stirred product using an ultrasonic device at a treatment power of 2.5 W / ml, a heating temperature of 30° C., a frequency range of 30 kHz, and a treatment time of 30 min;

[0043] (3) Continue to add epoxy resin, anti-settling agent, remaining 90wt.% organic solvent, epoxy reactive diluent and polysulfide rubber, use a high-speed disperser to stir, the stirring speed is 2000rpm, the stirring time is 40min, and epoxy graphene zinc-rich heavy anti-corrosion paint is obtained. The raw material composition of epoxy graphene zinc-rich heavy anti-corrosion paint is the same as that of Example 1.

[0044] The adhesion, corrosion resistance and other properties of the epoxy graphene zinc-rich heavy anti-corrosion paint of Example 1 and Comparative Examples 1 to 3 were tested. The ratings of moisture and heat resistance and salt spray resistance were based on the evaluation of the comprehensive aging performance grade of protective paint films in Section 5.2 of GB / T1766-2008. The test results are shown in Table 1.

[0045] As can be seen from Table 1, the present invention adopts

[0046] Table 1 Test results of various examples and comparative examples

[0047]

[0048] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.

Claims

1. A method for preparing epoxy graphene zinc-rich heavy anti-corrosion paint, characterized in that: The heavy anti-corrosion paint is composed of the following raw materials by mass percentage: 7-15% epoxy resin, 24-32% zinc powder, 0.4-0.7% graphene oxide, 3-6% wetting dispersant, 0.1-0.3% silane coupling agent, 1.5-2.5% anti-settling agent, 45-54% organic solvent, 0.8-1.2% epoxy active diluent, 1.5-2.0% polysulfide rubber, and 4-6% epoxy resin curing agent; the preparation method comprises the following steps: (1) mixing graphene oxide and zinc powder, washing with ultrapure water and ethanol in sequence, filtering, vacuum drying, and grinding to obtain a pretreated graphene oxide and zinc powder mixture A; (2) mixing the pretreated graphene oxide and zinc powder mixture A obtained in step (1) with ethanol at a mass ratio of 1:8-20 to obtain a suspension, adding the suspension to a high-temperature and high-pressure reactor, introducing nitrogen, and then reacting at a pressure of 3-5 MPa and a temperature of 244-260° C. for 1-1.5 h, releasing the pressure, cooling to room temperature, taking out the product, and vacuum drying to obtain a mixture B; (3) Mixing the mixture B obtained in step (2) with a silane coupling agent, a wetting dispersant and an organic solvent, stirring for the first time using a high-speed disperser, then ultrasonically treating, adding an epoxy resin, an anti-settling agent, an organic solvent, an epoxy reactive diluent and polysulfide rubber, and stirring for the second time using a high-speed disperser to obtain an epoxy graphene zinc-rich heavy anti-corrosion paint.

2. The preparation method according to claim 1, characterized in that: The epoxy value of the epoxy resin is 175-195 g / eq; the average particle size D50 of the zinc powder is 5-8 μm; the single-layer flake diameter of the graphene oxide is 0.1-8 μm, the amine value of the wetting dispersant is 9-12 mgKOH / g, and the molecular weight of the polysulfide rubber is 800-1200.

3. The preparation method according to claim 1, characterized in that: The silane coupling agent is one or more of vinyl trimethoxy silane, γ-aminopropyl triethoxy silane, and γ-glycidyloxypropyl trimethoxy silane; the main component of the anti-settling agent is polyamide wax; the organic solvent is one or more of xylene, ethylene glycol butyl ether acetate, and n-butanol; the epoxy diluent is one or more of butyl glycidyl ether, allyl glycidyl ether, and ethylene glycol diglycidyl ether.

4. The preparation method according to claim 1, characterized in that: In the step (1), the steps of washing and filtering with ultrapure water and ethanol in sequence are as follows: washing the mixture of graphene oxide and zinc powder with ultrapure water, filtering with filter paper, the pore size of the filter paper being in the range of 25nm-100nm; repeating the ultrapure water washing-filtering steps 2-5 times; Then wash with anhydrous ethanol, use a high-speed disperser for stirring during the washing process, the speed of the high-speed disperser is 1000-2000rpm, the stirring time is 3-5min, and filter paper is used for filtering, and the pore size range of the filter paper is 25nm-100nm; repeat the anhydrous ethanol washing-filtration steps 1-3 times.

5. The preparation method according to claim 1, characterized in that: In the step (1), the vacuum drying process parameters are: heating temperature is 100-150° C., heating time is 5-8 hours, and after grinding, the mixture is passed through a 400-600 mesh sieve.

6. The preparation method according to claim 1, characterized in that: In the step (2), the suspension is added into the high-temperature and high-pressure reactor, and the amount of the suspension added is 40-60% of the volume capacity of the high-temperature and high-pressure reactor.

7. The preparation method according to claim 1, characterized in that: In the step (2), the vacuum drying process parameters are: heating temperature is 100-150° C., and heating time is 1-3 h.

8. The preparation method according to claim 1, characterized in that: The ultrasonic treatment has a treatment power of 1-2.5 W / ml, a heating temperature of 30-40° C., a frequency range of 30-50 kHz, and a treatment time of 20-40 min.

9. The preparation method according to claim 1, characterized in that: In the step (3), the stirring speed of the first stirring is 1000-1500 rpm, and the stirring time is 30-50 min; the stirring speed of the second stirring is 1500-2000 rpm, and the stirring time is 40-50 min.

10. An epoxy graphene zinc-rich heavy anti-corrosion paint, characterized in that: The heavy anti-corrosion paint is prepared by the preparation method according to any one of claims 1 to 9.

Images