Environment-friendly and efficient paint remover, preparation method and application thereof

Abstract

The present application belongs to the technical field of paint removers, and particularly relates to an environment-friendly and efficient paint remover as well as a preparation method and application thereof. The environment-friendly and efficient paint remover comprises the following raw materials in mass fractions: 40-60 parts of a main solvent, 5-15 parts of a cosolvent, 2-5 parts of a surfactant, 1-3 parts of a thickening agent, 1-3 parts of silicon-containing imidazole compound modified nano-silicon dioxide, 1-3 parts of a long-chain fatty amide, 0.5-1 part of a nitrogen-containing heterocyclic compound, and 0.5-1 part of a sugar acid; the main solvent comprises a chain alcohol ether solvent and a cyclic nitrogen-containing solvent. The paint remover provided by the present application is low in toxicity, friendly to the environment, can effectively remove an electrophoretic paint film on a galvanized layer, and is low in corrosiveness.

Description

Technical Field

[0001] This invention belongs to the field of paint remover technology, specifically relating to an environmentally friendly and efficient paint remover, its preparation method, and its application. Background Technology

[0002] Electrophoretic coatings provide decorative appeal and corrosion protection to metal parts, such as rust prevention, impact resistance, and corrosion resistance, making them widely used in the protective coating of metal parts for industrial products such as automobiles, motorcycles, home appliances, and furniture. Currently, galvanized steel sheets are a common material in the manufacture of automotive parts. During the electrophoretic treatment process, imperfections inevitably occur in galvanized steel sheets, requiring rework and surface paint stripping for recoating.

[0003] Currently, dichloromethane-based paint removers are commonly used in industry. However, dichloromethane is highly volatile and toxic, posing a significant threat to the environment and human health. Therefore, developing environmentally friendly paint removers is of great importance.

[0004] Chinese Patent CN 120310330 A discloses an environmentally friendly water-based paint remover for tooling, its preparation method, and its application. Specifically, the environmentally friendly water-based paint remover for tooling comprises: 280-320 parts of main solvent, 40-54 parts of solubilizer, 30-40 parts of surfactant, 7-13 parts of penetrant, 130-150 parts of monoethanolamine, 8-12 parts of sulfonic acid, 40-58 parts of caustic soda flakes, 1-5 parts of thickener, and 280-320 parts of water; the main solvent is composed of benzyl alcohol and dipropylene glycol methyl ether in a weight ratio of 0.1-1:1-10. However, this technical solution is an alkaline paint remover, and the alkali will react with zinc, dissolving part of the zinc plating layer.

[0005] Chinese Patent Publication No. CN 120365785 A discloses a highly efficient and environmentally friendly paint remover and its preparation and removal methods. The paint remover includes a main solvent, a co-solvent, a surfactant, and a thickener. The main solvent includes diethylene glycol monobutyl ether, the co-solvent includes glycerol and propylene glycol carbonate, the surfactant includes anionic and nonionic surfactants, the nonionic surfactant includes sorbitan fatty acid ester and organosilicon surfactants, and the thickener includes xanthan gum and nano-alumina solution. However, this technical solution is only suitable for polyurethane coatings on aluminum alloy surfaces. Summary of the Invention

[0006] The purpose of this invention is to provide an environmentally friendly and efficient paint remover, its preparation method, and its application.

[0007] To achieve the above objectives, the present invention provides the following technical solution: The first aspect of this invention provides an environmentally friendly and efficient paint remover, comprising the following raw materials in parts by weight: 40-60 parts of main solvent, 5-15 parts of co-solvent, 2-5 parts of surfactant, 1-3 parts of thickener, 1-3 parts of silicone imidazole-containing modified nano-silica, 1-3 parts of long-chain fatty amide, 0.5-1 part of nitrogen-containing heterocyclic compound, and 0.5-1 part of uronic acid; The main solvent includes chain-like alcohol ether solvents and cyclic nitrogen-containing solvents.

[0008] In some embodiments of the present invention, the mass ratio of the chain alcohol ether solvent to the cyclic nitrogen-containing solvent is 6-8:2-4.

[0009] In some embodiments of the present invention, the chain-like alcohol ether solvent is a mixture of diethylene glycol dimethyl ether and ethylene glycol butyl ether.

[0010] In some embodiments of the present invention, the mass ratio of diethylene glycol dimethyl ether to ethylene glycol butyl ether is 3-4:1-2.

[0011] In some embodiments of the present invention, the cyclic nitrogen-containing solvent is a pyrrolidone compound.

[0012] In some embodiments of the present invention, the pyrrolidone compound is selected from at least one of N-ethylpyrrolidone, 1-phenyl-2-pyrrolidone, 1-octyl-2-pyrrolidone, N-ethylene-2-pyrrolidone, and N-hydroxyethyl-2-pyrrolidone.

[0013] Specifically, this invention uses chain-like alcohol ether solvents and cyclic nitrogen-containing solvents as main solvents. The chain-like alcohol ether solvents can quickly penetrate between the electrophoretic paint film and the substrate, disrupting the bonding force between the electrophoretic paint film and the substrate. The cyclic nitrogen-containing solvents can not only swell the electrophoretic paint, but the nitrogen atoms also have a certain protective effect on the galvanized sheet. The two work together to improve the paint remover's removal effect on the electrophoretic paint film and, to a certain extent, prevent the corrosion of the galvanized sheet. At the same time, it has low toxicity and is environmentally friendly.

[0014] In some embodiments of the present invention, the co-solvent is selected from at least one of ethanol, ethylene glycol, propylene glycol, glycerol, and butanol.

[0015] In some embodiments of the present invention, the surfactant is selected from at least one of polyoxyethylene alkylphenol ether, polyoxyethylene oxypropylene block copolymer, fatty alcohol polyethylene glycol ether, and castor oil polyoxyethylene ether.

[0016] In some embodiments of the present invention, the thickener is selected from at least one of carboxymethyl cellulose and hydroxyethyl cellulose.

[0017] In some embodiments of the present invention, the silimidazole-containing compound is selected from at least one of trimethylsilimidazole, 1-(dimethylisopropylsilane)imidazole and 1-(dimethylethylsilyl)imidazole.

[0018] In some embodiments of the present invention, the preparation method of the modified nano-silica containing silicone imidazole compound includes the following steps: mixing nano-silica and water, heating to 50-60°C and stirring for 10-20 minutes to form a homogeneous slurry, adding the silicone imidazole compound while stirring, raising the temperature to 80-90°C and continuing to stir for 30-40 minutes, filtering, washing, and drying to obtain the final product.

[0019] In some embodiments of the present invention, the particle size of the nano-silica is 50-100 nm.

[0020] In some embodiments of the present invention, the mass ratio of the nano-silica, the silicone imidazole compound and water is 15-20:1-2:60-80.

[0021] Specifically, this invention uses a silicone imidazole compound to modify nano-silica. The nitrogen atom on the imidazole ring of the silicone imidazole compound has strong basicity and coordination ability, which can destroy the cross-linking structure of the electrophoretic coating film. Under this premise, the nano-silica can penetrate deeper into the pores of the electrophoretic coating film, which further facilitates the penetration of the paint remover and improves the peeling of the electrophoretic coating film. The two play a synergistic role.

[0022] In some embodiments of the present invention, the long-chain fatty amide is selected from at least one of lauramide, oleamide and erucamide.

[0023] Specifically, the present invention also introduces long-chain fatty amides, which can cooperate with the main solvent and the modified nano-silica containing silicone imidazole compounds to improve the dissolution of the electrophoretic coating film and improve the removal efficiency.

[0024] In some embodiments of the present invention, the nitrogen-containing heterocyclic compound is selected from at least one of 2,3-dicarboxypyridine, 2,4-dicarboxypyridine, and 2,6-dicarboxypyridine.

[0025] In some embodiments of the present invention, the uronic acid is selected from at least one of D-glucuronic acid, D-mannuronic acid and D-galacturonic acid.

[0026] To prevent paint remover from corroding the zinc plating layer of the galvanized sheet, this invention specifically employs the combined action of a nitrogen-containing heterocyclic compound and uronic acid. The nitrogen atoms and carboxyl groups in the nitrogen-containing heterocyclic compound can form chelate complexes with zinc ions, while the aldehyde and carboxyl groups in the uronic acid can also form chelate complexes with zinc ions. Together, they form chemical bonds on the surface of the zinc plating layer, forming a mixed protective film, improving the density of the protective film, and thus preventing the zinc plating layer from being corroded.

[0027] The second aspect of this invention provides a method for preparing an environmentally friendly and efficient paint remover, comprising the following steps: mixing a main solvent, a co-solvent, a surfactant, a thickener, a nano-silica modified with a silicone imidazole compound, a long-chain fatty amide, a nitrogen-containing heterocyclic compound, and uronic acid, and stirring to obtain the final product.

[0028] The third aspect of this invention provides an environmentally friendly and efficient paint remover for use in metal parts of industrial products such as automobiles, motorcycles, home appliances, and furniture.

[0029] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: 1. This invention uses chain-like alcohol ether solvents and cyclic nitrogen-containing solvents as main solvents. The chain-like alcohol ether solvents can quickly penetrate between the electrophoretic paint film and the substrate, destroying the bonding force between the electrophoretic paint film and the substrate. The cyclic nitrogen-containing solvents can swell the electrophoretic paint, and nitrogen atoms have a certain protective effect on the galvanized sheet. The two work together to improve the paint remover's removal effect on the electrophoretic paint film and to a certain extent avoid corrosion of the galvanized sheet. At the same time, it has low toxicity and is environmentally friendly.

[0030] 2. This invention uses a silicone imidazole compound to modify nano-silica. The nitrogen atom on the imidazole ring of the silicone imidazole compound has strong basicity and coordination ability, which can destroy the cross-linking structure of the electrophoretic coating film. Under this premise, the nano-silica can penetrate deeper into the pores of the electrophoretic coating film, which further facilitates the penetration of the paint remover and improves the peeling of the electrophoretic coating film. The two play a synergistic role.

[0031] 3. This invention also introduces long-chain fatty amides, which can cooperate with the main solvent and the modified nano-silica containing silicone imidazole compounds to improve the dissolution of the electrophoretic coating film and improve the removal efficiency.

[0032] 4. This invention utilizes the combined action of nitrogen-containing heterocyclic compounds and uronic acid. The nitrogen atoms and carboxyl groups in the nitrogen-containing heterocyclic compounds can form chelate complexes with zinc ions, while the aldehyde and carboxyl groups in the uronic acid can also form chelate complexes with zinc ions. Together, they form chemical bonds on the surface of the zinc plating layer, forming a mixed protective film, which improves the density of the protective film and thus prevents the zinc plating layer from being corroded. Attached Figure Description

[0033] Figure 1This is the finished product test report of the environmentally friendly and efficient paint remover of Example 1 of the present invention. Detailed Implementation

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Unless otherwise specified, the raw materials, reagents, or apparatus used in the examples and comparative examples are all available from conventional commercial sources or can be obtained by existing technical methods. Unless otherwise specified, the test or experimental methods are conventional methods in the art. Example 1 An environmentally friendly and efficient paint remover is composed of the following raw materials in parts by weight: 40 parts main solvent, 5 parts co-solvent, 2 parts surfactant, 1 part thickener, 1 part modified nano-silica containing silicone imidazole compound, 1 part long-chain fatty amide, 0.5 parts nitrogen-containing heterocyclic compound, and 0.5 parts uronic acid.

[0036] The main solvents are chain alcohol ether solvents and cyclic nitrogen-containing solvents in a mass ratio of 7:3.

[0037] The chain-like alcohol ether solvent is a mixture of diethylene glycol dimethyl ether and ethylene glycol butyl ether in a mass ratio of 3:1.

[0038] The cyclic nitrogen-containing solvent is N-ethylpyrrolidone.

[0039] The cosolvent is propylene glycol.

[0040] The surfactant is castor oil polyoxyethylene ether, manufactured by Wenzhou Qingming Chemical Co., Ltd., with an index of EL40.

[0041] The thickener is hydroxyethyl cellulose.

[0042] A method for preparing nano-silica modified with silicone imidazole compounds includes the following steps: mixing nano-silica and water, heating to 60°C and stirring for 20 min to form a homogeneous slurry, adding trimethylsilicone imidazole while stirring, raising the temperature to 90°C and continuing to stir for 40 min, filtering, washing, and drying to obtain the final product.

[0043] The particle size of the nano-silica is 60 nm.

[0044] The mass ratio of nano-silica, trimethylsilimidazole and water is 15:1.5:60.

[0045] The long-chain fatty amide is lauramide.

[0046] The nitrogen-containing heterocyclic compound is 2,3-dicarboxypyridine.

[0047] Glucuronic acid is D-glucuronic acid.

[0048] The preparation method of the above-mentioned environmentally friendly and efficient paint remover includes the following steps: mixing the main solvent, co-solvent, surfactant, thickener, silicone imidazole-modified nano-silica, long-chain fatty amide, nitrogen-containing heterocyclic compound and uronic acid, and stirring to obtain the product.

[0049] Example 2 An environmentally friendly and efficient paint remover is composed of the following raw materials in parts by weight: 50 parts main solvent, 10 parts co-solvent, 3 parts surfactant, 2 parts thickener, 2 parts modified nano-silica containing silicone imidazole compound, 2 parts long-chain fatty amide, 0.8 parts nitrogen-containing heterocyclic compound, and 0.8 parts uronic acid.

[0050] The main solvents are chain alcohol ether solvents and cyclic nitrogen-containing solvents in a mass ratio of 7:3.

[0051] The chain-like alcohol ether solvent is a mixture of diethylene glycol dimethyl ether and ethylene glycol butyl ether in a mass ratio of 3:1.

[0052] The cyclic nitrogen-containing solvent is N-ethylpyrrolidone.

[0053] The cosolvent is propylene glycol.

[0054] The surfactant is castor oil polyoxyethylene ether, manufactured by Wenzhou Qingming Chemical Co., Ltd., with an index of EL40.

[0055] The thickener is hydroxyethyl cellulose.

[0056] A method for preparing nano-silica modified with silicone imidazole compounds includes the following steps: mixing nano-silica and water, heating to 60°C and stirring for 20 min to form a homogeneous slurry, adding trimethylsilicone imidazole while stirring, raising the temperature to 90°C and continuing to stir for 40 min, filtering, washing, and drying to obtain the final product.

[0057] The particle size of the nano-silica is 60 nm.

[0058] The mass ratio of nano-silica, trimethylsilimidazole and water is 15:1.5:60.

[0059] The long-chain fatty amide is lauramide.

[0060] The nitrogen-containing heterocyclic compound is 2,3-dicarboxypyridine.

[0061] Glucuronic acid is D-glucuronic acid.

[0062] The preparation method of the above-mentioned environmentally friendly and efficient paint remover includes the following steps: mixing the main solvent, co-solvent, surfactant, thickener, silicone imidazole-modified nano-silica, long-chain fatty amide, nitrogen-containing heterocyclic compound and uronic acid, and stirring to obtain the product.

[0063] Example 3 An environmentally friendly and efficient paint remover is composed of the following raw materials in parts by weight: 60 parts main solvent, 15 parts co-solvent, 5 parts surfactant, 3 parts thickener, 3 parts modified nano-silica containing silicone imidazole compound, 3 parts long-chain fatty amide, 1 part nitrogen-containing heterocyclic compound, and 1 part uronic acid.

[0064] The main solvents are chain alcohol ether solvents and cyclic nitrogen-containing solvents in a mass ratio of 7:3.

[0065] The chain-like alcohol ether solvent is a mixture of diethylene glycol dimethyl ether and ethylene glycol butyl ether in a mass ratio of 3:1.

[0066] The cyclic nitrogen-containing solvent is N-ethylpyrrolidone.

[0067] The cosolvent is propylene glycol.

[0068] The surfactant is castor oil polyoxyethylene ether, manufactured by Wenzhou Qingming Chemical Co., Ltd., with an index of EL40.

[0069] The thickener is hydroxyethyl cellulose.

[0070] A method for preparing nano-silica modified with silicone imidazole compounds includes the following steps: mixing nano-silica and water, heating to 60°C and stirring for 20 min to form a homogeneous slurry, adding trimethylsilicone imidazole while stirring, raising the temperature to 90°C and continuing to stir for 40 min, filtering, washing, and drying to obtain the final product.

[0071] The particle size of the nano-silica is 60 nm.

[0072] The mass ratio of nano-silica, trimethylsilimidazole and water is 15:1.5:60.

[0073] The long-chain fatty amide is lauramide.

[0074] The nitrogen-containing heterocyclic compound is 2,3-dicarboxypyridine.

[0075] Glucuronic acid is D-glucuronic acid.

[0076] The preparation method of the above-mentioned environmentally friendly and efficient paint remover includes the following steps: mixing the main solvent, co-solvent, surfactant, thickener, silicone imidazole-modified nano-silica, long-chain fatty amide, nitrogen-containing heterocyclic compound and uronic acid, and stirring to obtain the product.

[0077] Comparative Example 1 An environmentally friendly and highly efficient paint remover. The difference between this comparative example and Example 3 is that N-ethylpyrrolidone is replaced with an equal mass of dimethyl sulfoxide; all other aspects are the same.

[0078] The preparation method of the above-mentioned environmentally friendly and efficient paint remover is the same as in Example 3.

[0079] Comparative Example 2 An environmentally friendly and highly efficient paint remover. The difference between this comparative example and Example 3 is that N-ethylpyrrolidone is replaced with an equal mass of tetrahydrofurfuryl alcohol; all other aspects are the same.

[0080] The preparation method of the above-mentioned environmentally friendly and efficient paint remover is the same as in Example 3.

[0081] Comparative Example 3 An environmentally friendly and efficient paint remover. The difference between this comparative example and Example 3 is that the modified nano-silica containing a silicone imidazole compound is replaced with an equal mass of a silicone imidazole compound (trimethylsilicone imidazole); all other aspects are the same.

[0082] The preparation method of the above-mentioned environmentally friendly and efficient paint remover is the same as in Example 3.

[0083] Comparative Example 4 An environmentally friendly and efficient paint remover. The difference between this comparative example and Example 3 is that the modified nano-silica containing silicone imidazole compound is replaced with an equal mass of nano-silica; all other aspects are the same.

[0084] The preparation method of the above-mentioned environmentally friendly and efficient paint remover is the same as in Example 3.

[0085] Comparative Example 5 An environmentally friendly and efficient paint remover. The difference between this comparative example and Example 3 is that it lacks long-chain fatty amide, that is, the mass fraction of long-chain fatty amide is 0; all other aspects are the same.

[0086] The preparation method of the above-mentioned environmentally friendly and efficient paint remover is the same as in Example 3.

[0087] Comparative Example 6 An environmentally friendly and highly efficient paint remover. The difference between this comparative example and Example 3 is that 2,3-dicarboxypyridine is replaced with an equal mass of benzotriazole; all other aspects are the same.

[0088] The preparation method of the above-mentioned environmentally friendly and efficient paint remover is the same as in Example 3.

[0089] Comparative Example 7 An environmentally friendly and highly efficient paint remover. The difference between this comparative example and Example 3 is that D-glucuronic acid is replaced with an equal mass of 2,3-dicarboxypyridine; all other aspects are the same.

[0090] The preparation method of the above-mentioned environmentally friendly and efficient paint remover is the same as in Example 3.

[0091] Performance testing 1. Paint removal performance: The test substrate was galvanized sheet. An epoxy electrophoretic paint film with a thickness of 20µm was first prepared by electrophoresis. The paint removal efficiency of the paint remover was determined according to the method specified in HG / T 3381-2003. The paint removal temperature was 50℃, and the paint removal efficiency was tested after 15 minutes. The formula for calculating the paint removal efficiency is: Paint removal efficiency = Area of ​​wrinkled and soft paint film / Total area of ​​paint film before paint removal × 100%. 2. Corrosivity: Uncoated galvanized sheets were immersed in paint remover at 50°C for 72 hours, and their weight loss Δ was measured. m Calculate the corrosiveness of the paint remover, corrosion rate V=Δ m / (s·t), where s is the area of ​​the galvanized sheet and t is the immersion time; 3. Secondary electrophoresis: The galvanized sheet after paint removal with paint remover is then coated with an epoxy electrophoretic paint film with a thickness of 20µm. After neutral salt spray treatment for 960h, the corrosion phenomenon is observed.

[0092] The test results are shown in Table 1 below.

[0093] Table 1 Performance Test Results As can be seen from the results in Table 1 above: Compared to Example 3, Comparative Examples 1 and 2 showed decreased paint removal efficiency and increased corrosion rate due to changes in the composition of cyclic nitrogen-containing solvents, resulting in corrosion during secondary electrophoresis.

[0094] Comparative Examples 3 and 4, which only contained silicone imidazole compounds or nano-silica, showed a significant decrease in paint removal efficiency, indicating that silicone imidazole compounds and nano-silica have a synergistic paint removal effect.

[0095] Comparative Example 5 lacked long-chain fatty amides, resulting in a significant decrease in paint removal efficiency.

[0096] In Comparative Example 6, 2,3-dicarboxypyridine was replaced with benzotriazole, and in Comparative Example 7, D-glucuronic acid was replaced with 2,3-dicarboxypyridine. The corrosion rate increased significantly, indicating that 2,3-dicarboxypyridine and D-glucuronic acid have a synergistic corrosion inhibition effect.

[0097] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An environmentally friendly and highly efficient paint remover, characterized in that, The raw materials include the following parts by weight: 40-60 parts main solvent, 5-15 parts co-solvent, 2-5 parts surfactant, 1-3 parts thickener, 1-3 parts modified nano-silica containing silimidazole compound, 1-3 parts long-chain fatty amide, 0.5-1 part nitrogen-containing heterocyclic compound, and 0.5-1 part uronic acid. The main solvent includes chain-like alcohol ether solvents and cyclic nitrogen-containing solvents.

2. The environmentally friendly and efficient paint remover according to claim 1, characterized in that, The chain-like alcohol ether solvent is a mixture of diethylene glycol dimethyl ether and ethylene glycol butyl ether.

3. The environmentally friendly and efficient paint remover according to claim 2, characterized in that, The cyclic nitrogen-containing solvent is a pyrrolidone compound; the pyrrolidone compound is selected from at least one of N-ethylpyrrolidone, 1-phenyl-2-pyrrolidone, 1-octyl-2-pyrrolidone, N-ethylene-2-pyrrolidone, and N-hydroxyethyl-2-pyrrolidone.

4. The environmentally friendly and efficient paint remover according to claim 3, characterized in that, The silimidazole compound is selected from at least one of trimethylsilimidazole, 1-(dimethylisopropylsilane)imidazole and 1-(dimethylethylsilyl)imidazole.

5. The environmentally friendly and efficient paint remover according to claim 4, characterized in that, The preparation method of the modified nano-silica containing silicone imidazole compound includes the following steps: mixing nano-silica and water, heating to 50-60℃ and stirring for 10-20 minutes to form a homogeneous slurry, adding the silicone imidazole compound while stirring, raising the temperature to 80-90℃ and continuing to stir for 30-40 minutes, filtering, washing, and drying to obtain the final product.

6. The environmentally friendly and efficient paint remover according to any one of claims 1-5, characterized in that, The long-chain fatty amide is selected from at least one of lauramide, oleamide, and erucamide.

7. The environmentally friendly and efficient paint remover according to any one of claims 1-5, characterized in that, The nitrogen-containing heterocyclic compound is selected from at least one of 2,3-dicarboxypyridine, 2,4-dicarboxypyridine, and 2,6-dicarboxypyridine.

8. The environmentally friendly and highly efficient paint remover according to any one of claims 1-5, characterized in that, The uronic acid is selected from at least one of D-glucuronic acid, D-mannuronic acid, and D-galacturonic acid.

9. The method for preparing the environmentally friendly and efficient paint remover according to any one of claims 1-8, characterized in that, Includes the following steps: The main solvent, co-solvent, surfactant, thickener, silicone imidazole-modified nano-silica, long-chain fatty amide, nitrogen-containing heterocyclic compound, and uronic acid are mixed and stirred to obtain the final product.

10. The environmentally friendly and highly efficient paint remover according to any one of claims 1-8, characterized in that, The application of the environmentally friendly and efficient paint remover in metal parts of industrial products such as automobiles, motorcycles, home appliances, and furniture.

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