An epoxy graphene zinc-containing coating material, a preparation method and application thereof

Abstract

The present application relates to a kind of epoxy graphene zinc-containing paint and its preparation method and application, the paint includes the paint and curing agent with mass ratio (10~14):1;The component of paint includes by mass fraction: first solvent 10~20 parts, first epoxy resin 10~20 parts, graphene slurry 1~3 parts, zinc powder 30~40 parts, filler 30~50 parts and auxiliary agent 1~2 parts;The component of graphene slurry includes: second solvent 75~95 parts, high molecular type hyperdispersant 3~6 parts, carboxylate dispersant 1~5 parts, graphene powder 8~12 parts and thickening agent 1~2 parts.The present application prepares graphene slurry that can exist stably for a long time by hyperdispersant and carboxylate dispersant compound, then graphene and epoxy resin are bridged together by hydrogen bond of dispersant, so that graphene is uniformly dispersed in paint, and salt fog performance can reach more than 5000h under low zinc content, low graphene dosage.

Description

Technical Field

[0001] This invention belongs to the field of epoxy coatings, and particularly relates to an epoxy graphene zinc-containing coating, its preparation method, and its application. Background Technology

[0002] Epoxy graphene zinc powder coating is a high-performance anti-corrosion coating with advantages such as flexible film, high adhesion, and strong corrosion resistance. Its application in bridges, high-speed railway stations, airports, petrochemicals, and wind power is becoming increasingly widespread. The anti-corrosion principle of epoxy zinc-rich coatings (zinc powder content ≥60%) is the cathodic protection effect of zinc powder. In the coating film, zinc powder accumulates to form conductive pathways. Because zinc has a lower potential than iron, zinc reacts chemically with iron first, thereby protecting the iron substrate.

[0003] Graphene has a conjugated structure and high electron mobility. When added to zinc powder coatings, the effective overlap of graphene sheets ensures good conductivity between zinc powder particles, thus forming a conductive network. Furthermore, because sheet overlap efficiency is higher than spherical stacking, adding graphene can also reduce the amount of zinc powder required to some extent.

[0004] However, graphene is difficult to disperse evenly in zinc powder coatings and is prone to agglomeration in the coatings. This leads to a large amount of graphene used in epoxy zinc powder coatings, usually above 4‰, resulting in high formulation costs and affecting its application. Moreover, due to the poor anti-corrosion performance of commercially available epoxy curing agents, existing epoxy graphene zinc powder coatings still require more than 50% zinc powder to achieve 5000h salt spray resistance, which greatly wastes zinc resources, increases energy consumption, and increases carbon dioxide emissions. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned technical deficiencies and provide an epoxy graphene zinc-containing coating, its preparation method and application, to solve the technical problems of high cost caused by the large amount of zinc powder and graphene used in the existing epoxy graphene zinc-containing coating, or difficulty in achieving salt spray resistance.

[0006] To achieve the above-mentioned technical objectives, the technical solution provided by this invention is as follows: In a first aspect, the present invention provides an epoxy graphene zinc-containing coating, comprising a paint and a curing agent in a mass ratio of (10-14):1; by mass parts, the paint comprises: 10-20 parts of a first solvent, 10-20 parts of a first epoxy resin, 1-3 parts of graphene slurry, 30-40 parts of zinc powder, 30-50 parts of filler, and 1-2 parts of additives; the graphene slurry comprises: 75-95 parts of a second solvent, 3-6 parts of a polymeric superdispersant, 1-5 parts of a carboxylate dispersant, 8-12 parts of graphene powder, and 1-2 parts of a thickener.

[0007] Secondly, the present invention provides a method for preparing an epoxy graphene zinc-containing coating, comprising the following steps: adding a polymeric superdispersant, a carboxylate dispersant, and graphene powder to a second solvent, stirring evenly, and then adding a thickener to obtain a graphene slurry; adding a first epoxy resin to a first solvent, mixing evenly, then adding the graphene slurry and dispersing evenly, then adding zinc powder, fillers, and additives, and dispersing evenly to obtain a paint; and mixing the paint and a curing agent evenly to obtain an epoxy graphene zinc-containing coating.

[0008] Thirdly, the present invention provides an application of an epoxy graphene zinc-containing coating in the preparation of a heavy-duty anti-corrosion coating.

[0009] Compared with the prior art, the beneficial effects of the present invention include: This invention utilizes a combination of a superdispersant and a carboxylate dispersant to uniformly disperse graphene in a solvent, preparing a graphene slurry that can remain stable for a long time. This graphene slurry is then used to formulate a paint, where the graphene is bridged to the epoxy resin through hydrogen bonding with the dispersant, thus uniformly dispersing the graphene in the coating. Therefore, this invention can effectively reduce the zinc and graphene content in epoxy graphene zinc-containing coatings. With low zinc content and low graphene dosage, the salt spray performance can reach over 5000 hours, making it suitable as a primer for heavy-duty anti-corrosion coatings and showing promising application prospects. Detailed Implementation

[0010] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0011] Due to the difficulty in uniformly dispersing graphene in zinc powder coatings and the poor corrosion resistance of commercially available epoxy curing agents, existing epoxy graphene zinc powder coatings require more than 50% zinc powder to achieve a salt spray resistance of 5000 hours. This results in a significant waste of zinc resources, increased energy consumption, and increased carbon dioxide emissions. Furthermore, the amount of graphene used is typically above 0.4%, leading to high formulation costs and limiting its application.

[0012] Based on this, the present invention first prepares a graphene slurry that can uniformly disperse graphene in coatings, thereby reducing the amount of graphene used and lowering costs. Then, through formula optimization, a zinc-containing epoxy graphene coating is prepared. Furthermore, to improve the salt spray resistance of the coating and reduce the amount of zinc powder used, a curing agent for heavy-duty anti-corrosion epoxy coatings is prepared. The resulting zinc-containing epoxy graphene coating achieves a salt spray resistance of over 5000 hours even with low zinc content (30%) and low graphene dosage (2‰). Simultaneously, this product is inexpensive and has broad application prospects.

[0013] In a first aspect, the present invention provides an epoxy graphene zinc-containing coating, comprising a paint and a curing agent in a mass ratio of (10-14):1; by mass parts, The paint composition includes: 10-20 parts of first solvent, 10-20 parts of first epoxy resin, 1-3 parts of graphene slurry, 30-40 parts of zinc powder, 30-50 parts of filler, and 1-2 parts of additives; The graphene slurry comprises: 75-95 parts of a second solvent, 3-6 parts of a polymeric superdispersant, 1-5 parts of a carboxylate dispersant, 8-12 parts of graphene powder, and 1-2 parts of a thickener.

[0014] Preferably, the first solvent comprises xylene and n-butanol in a mass ratio of (5-10):(5-10).

[0015] Preferably, the first epoxy resin includes E20 epoxy resin.

[0016] Preferably, the filler includes ferrophosphorus powder.

[0017] Preferably, the additives include organobentonite; organobentonite is added as a thickener in the paint of the present invention.

[0018] Preferably, the second solvent comprises xylene and n-butanol in a mass ratio of (60-70):(15-25).

[0019] Preferably, the polymeric superdispersant includes polyester superdispersant SP-24000 (Shanghai Zhehua).

[0020] Preferably, the carboxylate dispersant includes the alkylammonium salt ATU 203 (BYK) of a polycarboxylic acid. Preferably, the thickener includes polyamide wax powder.

[0021] Preferably, the curing agent comprises, by weight, 20-30 parts of phenylenediamine, 30-40 parts of the second epoxy resin, 15-25 parts of benzyl alcohol, and 20-25 parts of the third solvent.

[0022] More preferably, the phenylenediamine includes one or two of o-phenylenediamine, m-phenylenediamine, and p-phenylenediamine; More preferably, the second epoxy resin includes E12 epoxy resin.

[0023] More preferably, the third solvent includes xylene.

[0024] Secondly, the present invention provides a method for preparing an epoxy graphene zinc-containing coating, comprising the following steps: A high molecular weight superdispersant, a carboxylate dispersant, and graphene powder are added to a second solvent, stirred evenly, and then a thickener is added to obtain a graphene slurry. The first epoxy resin is added to the first solvent and mixed evenly. Then, graphene slurry is added and dispersed evenly. Zinc powder, filler and additives are added and dispersed evenly to obtain the paint. The paint and curing agent are mixed evenly to obtain an epoxy graphene zinc-containing coating.

[0025] Preferably, the preparation steps of the curing agent include: mixing phenylenediamine, the second epoxy resin, benzyl alcohol and the third solvent evenly, heating to 55-65°C, holding at the temperature for 5-7 hours and then cooling to room temperature to obtain the curing agent.

[0026] Thirdly, the present invention provides an application of an epoxy graphene zinc-containing coating in the preparation of a heavy-duty anti-corrosion coating.

[0027] The main mechanism and advantages of this invention are as follows: First, graphene slurry is prepared: graphene is uniformly dispersed in a solvent by combining a superdispersant and a carboxylate dispersant to prepare a graphene slurry that can exist stably for a long time. Secondly, graphene paint is prepared: graphene and epoxy resin are bridged together through the hydrogen bonding of the dispersant, thereby uniformly dispersing graphene in the coating. Secondly, a self-made epoxy curing agent was prepared by ternary polymerization of phenylenediamine with E12 epoxy resin and benzyl alcohol, taking advantage of the corrosion resistance of the benzene ring and the flexibility of E12 resin. This invention involves mixing paint with a self-made epoxy curing agent in a specific ratio to prepare an epoxy graphene zinc-containing coating. Using a self-made graphene slurry and a self-made epoxy curing agent, the coating exhibits excellent salt spray resistance (5000h) while significantly reducing zinc powder usage (from 50% to 30%) and graphene usage (from 4‰ to approximately 2‰), and also offers higher cost-effectiveness. Simultaneously, it conserves zinc resources and reduces energy consumption and carbon dioxide emissions.

[0028] The present invention will be further described in detail below through specific embodiments.

[0029] Example 1 An epoxy graphene zinc-containing coating and its preparation method, comprising the following steps: (1) Preparation of graphene slurry: After mixing 640g xylene and 200g n-butanol evenly, add 35g polyester superdispersant SP-24000 and 15g polycarboxylic acid alkyl ammonium salt ATU 203. After dispersing at 400r / min for 5 minutes, add 100g graphene powder, stir at 800r / min for 1 hour, and then add 10g polyamide wax powder to obtain graphene slurry; (2) Preparation of paint: Mix 90g xylene and 60g n-butanol evenly, add 150g E20 epoxy resin, stir at 600r / min for 10 minutes, add 20g graphene slurry, disperse at 800r / min for 0.5h, add 320g zinc powder, 350g iron phosphate powder and 10g organic bentonite, disperse at 1000r / min for 1h to obtain paint; (3) Preparation of curing agent: 280g phenylenediamine, 330g E12 epoxy resin, 170g benzyl alcohol, and 220g xylene were added to a dropping vessel and mixed evenly to obtain a mixture. The mixture was heated to 60℃, stirred at 300r / min, kept at this temperature for 6h, and then cooled to room temperature to obtain the curing agent; (4) Preparation of epoxy graphene zinc-containing coating: The paint and curing agent are mixed evenly at a mass ratio of 12:1 to prepare epoxy graphene zinc-containing coating. In this epoxy graphene zinc-containing coating, the zinc powder content is 30% and the graphene content is 2‰.

[0030] Example 2 The only difference from Example 1 is that the amount of phenylenediamine is adjusted to 250g and the amount of benzyl alcohol is adjusted to 200g. The other steps and conditions are the same as in Example 1.

[0031] Example 3 The only difference from Example 1 is that the amount of phenylenediamine is adjusted to 300g and the amount of benzyl alcohol is adjusted to 150g. The other steps and conditions are the same as in Example 1.

[0032] Example 4 The only difference from Example 1 is that the amount of polymeric superdispersant is adjusted to 30g and the amount of carboxylate dispersant is adjusted to 20g. The other steps and conditions are the same as in Example 1.

[0033] Example 5 The only difference from Example 1 is that the amount of polymeric superdispersant is adjusted to 40g and the amount of carboxylate dispersant is adjusted to 10g. The other steps and conditions are the same as in Example 1.

[0034] Comparative Example 1 The only difference from Example 1 is that commercially available graphene slurry KNG-CC401 (Xiamen Kaina) is used instead of the graphene slurry obtained in step (1), and the other steps and conditions are the same as in Example 1.

[0035] Comparative Example 2 The only difference from Example 1 is that the commercially available curing agent NX-2003 (Cardley, phenolic amine curing agent) is used instead of the curing agent obtained in step (3), and the other steps and conditions are the same as in Example 1.

[0036] Comparative Example 3 The only difference from Example 1 is that the commercially available graphene slurry KNG-CC401 (Xiamen Kaina) is used to replace the graphene slurry obtained in step (1), and the commercially available curing agent NX-2003 (Cardley, phenolic amine curing agent) is used to replace the curing agent obtained in step (3). The other steps and conditions are the same as in Example 1.

[0037] Comparative Example 4 The only difference from Example 1 is that the amount of phenylenediamine is adjusted to 190g and the amount of benzyl alcohol is adjusted to 260g. The other steps and conditions are the same as in Example 1.

[0038] Comparative Example 5 The only difference from Example 1 is that benzyl alcohol in step (3) is removed and replaced with xylene, while the other steps and conditions are the same as in Example 1.

[0039] Performance testing The epoxy graphene zinc-containing coatings prepared in Examples 1-5 and Comparative Examples 1-5 were used to prepare coatings, and the salt spray performance of the coatings was tested according to GB / T1771 "Determination of resistance to neutral salt spray of paints and varnishes". The test results are shown in Table 1.

[0040] Table 1 Comparison of Salt Spray Performance of Coatings

[0041] Note: The zinc powder content is 30% and the graphene content is 2‰.

[0042] As shown in Table 1, under the conditions of low zinc powder content (30%) and low graphene content (2‰), the salt spray resistance of the epoxy graphene zinc-containing coatings (Examples 1-5) prepared by the present invention can all reach more than 5000h.

[0043] When commercially available graphene slurry is used (Comparative Example 1), the graphene cannot be chemically bridged with the epoxy resin, resulting in the graphene not being uniformly dispersed in the coating, and its salt spray resistance is reduced by about 35% compared to Example 1.

[0044] When a commercially available curing agent is used (Comparative Example 2), the salt spray resistance of the coating decreases by about 50% compared to Example 1 due to the poor corrosion resistance of the existing curing agent.

[0045] When commercially available graphene slurry and commercially available curing agent are used (Comparative Example 3), the salt spray performance is the worst, decreasing by about 68% compared to the examples, because graphene cannot be uniformly dispersed in the coating and the existing curing agent has poor corrosion resistance.

[0046] When the amount of phenyl diammonium decreases (Comparative Example 4), since the amount of E12 remains unchanged and the amount of benzyl alcohol increases, a large amount of phenyl diammonium is consumed by the addition reaction during the preparation of the curing agent, resulting in a decrease in the active hydrogen content of the curing agent, an excessive epoxy / amine ratio, and a decrease in the salt spray resistance of the coating film.

[0047] When the amounts of phenyl diammonium and E12 remain unchanged, and the curing agent does not contain benzyl alcohol (Comparative Example 5), during the preparation of the curing agent, phenyl diammonium only reacts with E12, resulting in an increase in the active hydrogen content of the curing agent, an excessively low epoxy / amine ratio, and a significant reduction in the salt spray resistance of the coating film.

[0048] In summary, this invention prepares a uniformly dispersed graphene slurry by compounding a polymeric superdispersant and a carboxylate dispersant; prepares a paint by screening epoxy resin, filler, zinc powder dosage, and graphene dosage; and prepares a high-performance curing agent through ternary polymerization of phenylenediamine, E12 epoxy resin, and benzyl alcohol. The epoxy graphene zinc-containing coating prepared from the paint and curing agent can achieve a salt spray performance of over 5000 hours under low zinc content (30%) and low graphene dosage (2‰), and can be used as a primer for heavy-duty anti-corrosion coatings, showing good application prospects.

[0049] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. An epoxy graphene zinc-containing coating, characterized in that, Includes paint and hardener in a mass ratio of (10-14):1; by mass parts, The paint composition includes: 10-20 parts of first solvent, 10-20 parts of first epoxy resin, 1-3 parts of graphene slurry, 30-40 parts of zinc powder, 30-50 parts of filler, and 1-2 parts of additives; The graphene slurry comprises: 75-95 parts of a second solvent, 3-6 parts of a polymeric superdispersant, 1-5 parts of a carboxylate dispersant, 8-12 parts of graphene powder, and 1-2 parts of a thickener. The polymeric superdispersant includes polyester-based superdispersants; the carboxylate dispersant includes alkyl ammonium salts of polycarboxylic acids.

2. The epoxy graphene zinc-containing coating according to claim 1, characterized in that, The first epoxy resin includes E20 epoxy resin.

3. The epoxy graphene zinc-containing coating according to claim 1, characterized in that, The first solvent comprises xylene and n-butanol in a mass ratio of (5-10):(5-10); The filler includes ferrophosphorus powder; The additives include organobentonite.

4. The epoxy graphene zinc-containing coating according to claim 1, characterized in that, The second solvent comprises xylene and n-butanol in a mass ratio of (60-70):(15-25); The thickener includes polyamide wax powder.

5. The epoxy graphene zinc-containing coating according to claim 1, characterized in that, The curing agent comprises, by weight, 20-30 parts of phenylenediamine, 30-40 parts of the second epoxy resin, 15-25 parts of benzyl alcohol, and 20-25 parts of the third solvent.

6. The epoxy graphene zinc-containing coating according to claim 5, characterized in that, The phenylenediamine includes one or two of o-phenylenediamine, m-phenylenediamine, and p-phenylenediamine; The second epoxy resin includes E12 epoxy resin; The third solvent includes xylene.

7. The method for preparing the epoxy graphene zinc-containing coating according to any one of claims 1-6, characterized in that, Includes the following steps: A high molecular weight superdispersant, a carboxylate dispersant, and graphene powder are added to a second solvent, stirred evenly, and then a thickener is added to obtain a graphene slurry. The first epoxy resin is added to the first solvent and mixed evenly. Then, graphene slurry is added and dispersed evenly. Zinc powder, filler and additives are added and dispersed evenly to obtain the paint. The paint and curing agent are mixed evenly to obtain an epoxy graphene zinc-containing coating.

8. The method for preparing the epoxy graphene zinc-containing coating according to claim 7, characterized in that, The preparation steps of the curing agent include: mixing phenylenediamine, second epoxy resin, benzyl alcohol and third solvent evenly, heating to 55-65°C, holding at the temperature for 5-7 hours and then cooling to room temperature to obtain the curing agent.

9. The application of an epoxy graphene zinc-containing coating as described in any one of claims 1-6 in the preparation of a heavy-duty anti-corrosion coating.

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