Environment-friendly anticorrosive coating and preparation method thereof

Abstract

This invention discloses an environmentally friendly anti-corrosion coating. By weight, it comprises the following raw materials: 40-60 parts epoxy resin, 10-20 parts hydroxyl-containing bio-based polymer, 20-30 parts aminosilane, 5-10 parts reactive diluent, 5-10 parts coloring pigment, 30-60 parts extender filler, and 10-20 parts curing agent. The preparation method includes the following steps: ① Add a small amount of formic acid to a reaction vessel, adjust the pH to 4-5 with water, stir, add aminosilane, maintain the pH between 4-5, and hydrolyze for 30-60 minutes; wherein the mass ratio of formic acid to aminosilane is 1:15-1:30; ② Add a hydroxyl-containing bio-based polymer to ①, heat to 60-90℃, stir for 50-90 minutes; when the pH of the system rises to 6-7, add epoxy resin, heat to 60-90℃, stir for 1-3 hours, and cool to room temperature; ③ Add reactive diluent, coloring pigment, and extender filler to ②, stir and disperse evenly to obtain component A; ④ Mix the curing agent and a small amount of reactive diluent, stir evenly to obtain component B; ⑤ Mix component A and component B evenly, and it is ready for use.

Description

Technical Field

[0001] This invention relates to the field of anti-corrosion coatings, and more particularly to an environmentally friendly anti-corrosion coating and its preparation method. Background Technology

[0002] Traditional heavy-duty anti-corrosion coatings contain many organic solvents, increasing volatile organic compounds (VOCs) in the construction environment. These VOCs contribute to greenhouse gas emissions from factories, and are a major source of smog. Reducing VOC emissions can significantly reduce health hazards to construction workers and surrounding residents. Furthermore, traditional heavy-duty anti-corrosion coatings often use large amounts of zinc powder to create zinc-rich epoxy primers, thereby increasing the corrosion resistance of the coating after scratches in marine environments. However, zinc powder has been proven to cause irreversible damage to soil and aquatic life in Europe and America. To meet increasingly stringent environmental requirements and related laws and regulations, anti-corrosion coatings are gradually developing towards solvent-free and water-based solutions.

[0003] Solvent-free anti-corrosion epoxy coatings, as a new type of environmentally friendly anti-corrosion coating, are gradually becoming known to the public due to their excellent anti-corrosion performance and pollution-free characteristics. Patent CN117777817A discloses a solvent-free epoxy anti-corrosion coating containing a modified epoxy toughening curing agent. Patent CN115989287B discloses a two-component coating composition comprising a first liquid and a second liquid; Patent CN102559016B discloses a high-solids epoxy coating formulation with up to 10 components, its preparation process, and its application; Patent CN115926583A discloses an environmentally friendly modified epoxy resin coating and its preparation method; Patent CN116162390B relates to an epoxy resin emulsion-modified waterborne coating and its preparation process; Patent CN102732130B discloses a high-solids anti-corrosion coating suitable for spraying and its preparation method, the components of which include epoxy resin, modified epoxy resin, etc.; Patent CN104817899A discloses a modified wear-resistant weed trimmer coating, using corn starch, epoxy resin-modified organosilicon, and aminosilane, etc.; and CN110643268A discloses an environmentally friendly anti-corrosion coating and its preparation method. The aforementioned anti-corrosion coating technologies are not yet perfect, mainly due to the large number of components, complex processes, high costs, and the need for further improvement in overall anti-corrosion effect, service life, and application.

[0004] Therefore, the main technical problems existing in current anti-corrosion coatings are: (1) The use of volatile organic compounds and zinc powder in traditional heavy-duty anti-corrosion coatings poses a significant threat to the environment and human health.

[0005] (2) The anti-corrosion coating technology is not yet perfect, mainly reflected in the fact that there are many components, the process is complex, the cost is high, and the overall anti-corrosion effect, service life and application need to be further improved. Summary of the Invention

[0006] The purpose of this invention is to provide an environmentally friendly anti-corrosion coating and its preparation method in order to solve the above-mentioned problems.

[0007] The objective of this invention is achieved through the following technical solution: An environmentally friendly anti-corrosion coating and its preparation method are disclosed. The environmentally friendly anti-corrosion coating is based on epoxy resin, hydroxyl-containing bio-based polymer, and aminosilane. The coating is formed by reacting the -Si-O- of aminosilane with the hydroxyl groups in the hydroxyl-containing bio-based polymer, and simultaneously crosslinking the -NH2 of aminosilane with the epoxy resin to form a "bio-based polymer-silane-epoxy" ternary network.

[0008] This can be understood as follows: aminosilane reacts with hydroxyl-containing bio-based polymers, while its -NH2 crosslinks with epoxy resin to form a "bio-based polymer-silane-epoxy" ternary network, which improves the environmental friendliness and anti-corrosion performance of the coating.

[0009] The specific plan is as follows: An environmentally friendly anti-corrosion coating, by weight, comprises the following raw materials: 40-60 parts epoxy resin, 10-20 parts hydroxyl-containing bio-based polymer, 20-30 parts aminosilane, 5-10 parts reactive diluent, 5-10 parts coloring pigment, 30-60 parts extender filler, and 10-20 parts curing agent.

[0010] The epoxy resin is a low-molecular-weight liquid epoxy resin, including one or more of bisphenol A epoxy resin and bisphenol F epoxy resin.

[0011] The hydroxyl-containing bio-based polymer is starch, polyhydroxybutyrate-valerate copolymer, or a mixture of the two.

[0012] The active diluent is one or more of the following: alkyl glycidyl ether, tertiary glycidyl ether, butyl glycidyl ether, tertiary glycidyl ether, and cyclohexanediol diglycidyl ether.

[0013] The curing agent is one of polyamide and polyetheramine.

[0014] The coloring pigment is one or more of the following: titanium dioxide, furnace black, iron oxide red, yellow iron oxide, iron oxide black, phthalocyanine blue, aluminum silver paste, graphite, zinc sulfide, zinc oxide, chromium oxide, yellow nickel titanium, yellow chromium titanium, phthalocyanine blue, and phthalocyanine green pigment.

[0015] The bulk filler is composed of precipitated barium sulfate, heavy calcium carbonate, talc, clay, calcium carbonate, magnesium carbonate, barium sulfate, silicic acid, silicates, alumina, calcium sulfate, mica iron oxide (MIO), glass flakes, and mica.

[0016] A method for preparing an environmentally friendly anti-corrosion coating specifically includes the following steps: ① Add a small amount of formic acid to the reaction vessel, adjust the pH to 4-5 with water, stir, add aminosilane, keep the pH between 4-5, and hydrolyze for 30-60 minutes; the mass ratio of formic acid to aminosilane used is 1:15-1:30. ② Add hydroxyl-containing bio-based polymer to ①, heat to 60-90℃, and stir for 50-90 minutes; when the pH of the system rises to 6-7, add epoxy resin, heat to 60-90℃, stir for 1-3 hours, and cool to room temperature; ③ Add reactive diluent, coloring pigment, and extender to ②, stir and disperse evenly to obtain component A; ④ Mix the curing agent and a small amount of reactive diluent, with a mass ratio of curing agent to reactive diluent of 10:1 to 20:1, and stir evenly to obtain component B; ⑤ Mix components A and B thoroughly, and it is ready for use.

[0017] In the above reaction process, the added formic acid and water will evaporate together during heating.

[0018] The environmentally friendly anti-corrosion coating can be applied to a substrate, at least a portion of which is coated with the environmentally friendly anti-corrosion coating described in this application; preferably, the substrate comprises at least one of the following: steel or aluminum.

[0019] The environmentally friendly anti-corrosion coating or the above-mentioned substrate described in this application can also be used in marine engineering such as shipbuilding, offshore wind power, and offshore oil platforms.

[0020] The environmentally friendly anti-corrosion coating proposed in this invention has the following characteristics: 1. The -Si-O- groups in the aminosilane react with the hydroxyl-containing bio-based polymer, while the -NH2 groups of the aminosilane crosslink with the epoxy resin to form a "bio-based polymer-silane-epoxy" ternary network, which gives the prepared coating better performance.

[0021] 2. Using bio-based polymers, the process is low-cost, green, and efficient, and does not harm the environment. Therefore, the resulting coatings are zinc-free, solvent-free, and highly corrosion-resistant.

[0022] Through comparative experiments, the environmentally friendly anti-corrosion coating prepared in this application has the advantages of strong adhesion, high strength, good toughness, low VOC content, good impact resistance, oil resistance, and salt spray resistance. It also shows good application effect on steel, aluminum and other substrates and can be widely used in marine engineering such as shipbuilding, offshore wind power, and offshore oil platforms. Detailed Implementation

[0023] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. It should be noted that, unless otherwise specified, the experimental methods used in the following embodiments are conventional methods; and the materials and reagents used in the following embodiments are commercially available unless otherwise specified.

[0024] Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available products. To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below.

[0025] Example 1 The following raw materials in parts by weight are used: 50 parts bisphenol A epoxy resin, 20 parts starch, 30 parts aminosilane, 10 parts reactive diluent, 10 parts coloring pigment, 50 parts extender filler, and 20 parts polyamide curing agent. The preparation method is as follows: ① Add 1-2 parts of formic acid to the reaction vessel, adjust the pH to 4-5 with water, stir, add aminosilane, keep the pH between 4-5, and hydrolyze for 30-60 minutes; ② Add hydroxyl-containing bio-based polymer to ①, heat to 60-90℃, and stir for 50-90 minutes; when the pH of the system rises to 6-7, add epoxy resin, heat to 60-90℃, stir for 1-3 hours, and cool to room temperature; ③ Add reactive diluent, coloring pigment, and extender to ②, stir and disperse evenly to obtain component A; ④ Mix the curing agent and the reactive diluent in a mass ratio of 10:1 to 20:1, and stir until homogeneous to obtain component B; ⑤ Mix components A and B thoroughly.

[0026] Examples 2-5

[0027] Take the components in the mass fractions shown in Table 1: Table 1. Raw material composition ratio of environmentally friendly anti-corrosion coatings in Examples 2-5 ;

[0028] An environmentally friendly anti-corrosion coating was prepared using the preparation method described in Example 1. The proportions of each component were different, but the formulations were as shown in Table 1; all other steps remained the same.

[0029] Comparative Example 1

[0030] The difference from Example 1 is that no starch or polyhydroxybutyrate copolymer was added.

[0031] Comparative Example 2

[0032] The difference from Example 1 is that no aminosilane was added.

[0033] Test Example 1

[0034] The size is Q235 steel sheets were polished with 400-grit sandpaper, wiped with ethanol, and dried to obtain pretreated Q235 steel sheets. 3-Aminopropyltriethylsilane was added to the anti-corrosion coatings prepared by the methods in Examples 1-5 and Comparative Examples 1-2, and stirred for 10 minutes. The ratio of coating to curing agent was 10:1. The coating with added curing agent was evenly sprayed onto the pretreated steel sheets by spraying. The sheets were baked at 200°C for 2 minutes and then quickly immersed in 30°C cold water for 10 seconds to obtain the anti-corrosion and wear-resistant coatings corresponding to the methods in Examples 1-5 and Comparative Examples 1-2. The coating film thickness was 25 μm, and tests were conducted.

[0035] The anti-corrosion coatings prepared in Examples 1-5 and Comparative Examples 1-2 were subjected to performance tests. The test items and methods are as follows: Viscosity (in cPs): 26℃, measured using a Bollerfeld rotational viscometer; Adhesion (unit: MPa): GB / T5210; Hardness (unit: H): GB / T6739; Flexibility (unit: mm): GB / T1731; Neutral salt spray resistance (h): GB / T1771; Volatile organic compound content (unit: mg / m³) 3 GB / T34682; Resistance to media (diesel, normal temperature, h): GB / T9274; Impact resistance (J): GB / T2567.

[0036] The test results are shown in Table 2: Table 2 Test results of the anti-corrosion coatings obtained in Examples 1-5 and Comparative Examples 1-2 ;

[0037] Analysis of the data in the table above shows that the environmentally friendly anti-corrosion coating of the present invention has the advantages of strong adhesion, high strength, good toughness, low VOC content, and good impact resistance, oil resistance, and salt spray resistance.

[0038] The paper also demonstrates that the environmentally friendly anti-corrosion coating exhibits good performance on steel, aluminum, and other substrates, and can be widely applied in marine engineering projects such as shipbuilding, offshore wind power, and offshore oil platforms. Experimental verification shows that, compared to the products in Comparative Examples 1-2, it possesses advantages such as strong adhesion, high strength, good toughness, low VOC content, and good impact resistance, oil resistance, and salt spray resistance, demonstrating excellent application results.

[0039] The embodiments described above provide a detailed explanation of the technical solutions and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, additions, and equivalent substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An environmentally friendly anti-corrosion coating, characterized in that, The coating comprises, by weight parts, the following raw materials: 40-60 parts epoxy resin, 10-20 parts hydroxyl-containing bio-based polymer, 20-30 parts aminosilane, 5-10 parts reactive diluent, 5-10 parts coloring pigment, 30-60 parts extender filler, and 10-20 parts curing agent; wherein the epoxy resin is a low-molecular-weight liquid epoxy resin, including one or more of bisphenol A epoxy resin and bisphenol F epoxy resin; wherein the hydroxyl-containing bio-based polymer is starch, polyhydroxybutyrate-valerate copolymer, or a mixture of the above two; the preparation method of the environmentally friendly anti-corrosion coating includes the following steps: ① Add a small amount of formic acid to the reaction vessel, adjust the pH to 4-5 with water, stir, add aminosilane, keep the pH between 4-5, and hydrolyze for 30-60 minutes; the mass ratio of formic acid to aminosilane used is 1:15-1:

30. ② Add hydroxyl-containing bio-based polymer to ①, heat to 60-90℃, and stir for 50-90 minutes; when the pH of the system rises to 6-7, add epoxy resin, heat to 60-90℃, stir for 1-3 hours, and cool to room temperature; ③ Add reactive diluent, coloring pigment, and extender to ②, stir and disperse evenly to obtain component A; ④ Mix the curing agent and a small amount of reactive diluent, wherein the mass ratio of the curing agent to the reactive diluent is 10:1 to 20:1, and stir evenly to obtain component B; ⑤ Mix components A and B thoroughly, and it is ready for use.

2. The environmentally friendly anti-corrosion coating according to claim 1, characterized in that, The active diluent is one or more of alkyl glycidyl ether, tert-carbonate glycidyl ether, and cyclohexanediol diglycidyl ether diluent.

3. The environmentally friendly anti-corrosion coating according to claim 1, characterized in that, The curing agent is one of polyamide and polyetheramine.

4. The environmentally friendly anti-corrosion coating according to claim 1, characterized in that, The coloring pigment is one or more of the following: titanium dioxide, furnace black, iron oxide red, yellow iron oxide, iron oxide black, aluminum silver paste, graphite, zinc sulfide, zinc oxide, chromium oxide, yellow nickel titanium, yellow chromium titanium, phthalocyanine blue, and phthalocyanine green pigment.

5. The environmentally friendly anti-corrosion coating according to claim 1, characterized in that, The bulk filler is composed of precipitated barium sulfate, talc, clay, calcium carbonate, magnesium carbonate, barium sulfate, silicate, alumina, calcium sulfate, mica iron oxide, glass flakes, and mica.

6. A substrate, at least a portion of which is coated with an environmentally friendly anti-corrosion coating according to any one of claims 1-5; said substrate comprising at least one of the following: steel, aluminum.

7. The application of the substrate according to claim 6 in marine engineering, characterized in that, include: Applications in shipbuilding, offshore wind power, and offshore oil.