Preparation method of chromium-free fingerprint-resistant liquid for aluminized zinc plate

Abstract

The invention discloses a preparation method of chromium-free fingerprint-resistant liquid for an aluminized zinc plate, and relates to the technical field of metal surface treatment materials.The preparation method comprises the steps that a benzotriazole-cerium molybdate composite corrosion inhibition system is constructed, and multiple layers of adsorption films are formed through intermolecular pi-pi accumulation and rare earth ion coordination; meanwhile, a graphene oxide / nano silicon dioxide synergistic enhancement system is introduced, graphene sheet layers are directionally arranged to form a physical barrier, and micropores are filled with nano particles to improve compactness; and meanwhile, a lanthanide rare earth compound is adopted for modifying the flash-rust inhibitor, the stability of a passivation film on the metal surface is enhanced through the empty orbital characteristic of rare earth elements, the nanometer material gradient dispersion technology is combined with the ultrasonic-mechanical coupling dispersion technology, filler uniform distribution and interface bonding strengthening are achieved, and the fingerprint resistance, corrosion resistance and the like of the film layer are effectively guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of metal surface treatment agents, and more specifically, to a preparation method of a chromium-free fingerprint-resistant liquid for aluminized zinc plates. Background Art

[0002] At present, with the improvement of people's living quality, products such as automobiles, household appliances, and daily necessities are constantly updated, and higher requirements are put forward for the aesthetics and environmental protection of products. The performance of the steel plates used on the product surfaces directly affects the aesthetics of the products. Therefore, in view of the problem that clear fingerprints are easily left when touching the conventional steel plates, fingerprint-resistant steel plates have been researched and developed. The fingerprint-resistant steel plate is a composite coated plate obtained by performing fingerprint-resistant treatment on the steel plate surface. Its surface is smooth, flat, and has a small tolerance. When touching its surface with a clean finger, no fingerprints will be left. At present, the fingerprint-resistant steel plates are developing in the direction of integrating multiple properties, and the fingerprint-resistant steel plates that can meet multiple usage requirements have broad application prospects.

[0003] Currently, the chromium-free fingerprint-resistant liquid for aluminized zinc on the market comprehensively considers fingerprint resistance, corrosion resistance, high hardness, scratch resistance, electrical conductivity, self-lubrication, and paintability, etc., but ignores the adhesion between the fingerprint-resistant film layer and the substrate. Due to the insufficient adhesion between the film layer and the substrate, the fingerprint-resistant layer fails to play a role in protecting the metal layer, and the metal layer directly undergoes friction during transportation and processing, resulting in a large number of black spots. Referring to the patent No. CN202410505073, a cationic two-component chromium-free aluminized zinc fingerprint-resistant liquid is used. The fingerprint-resistant liquid in this invention easily reacts with the substrate, resulting in black spots or black patches on the substrate.

[0004] Therefore, in order to solve the problem of poor adhesion between the fingerprint-resistant coating and the substrate, so that no black spot phenomenon occurs during transportation and processing, and at the same time having fingerprint resistance, corrosion resistance, high hardness, scratch resistance, electrical conductivity, self-lubrication, and paintability, etc., based on the above problems, we provide a preparation method of a chromium-free fingerprint-resistant liquid for aluminized zinc plates. Summary of the Invention

[0005] In order to solve the problems raised in the above background art, the present invention provides a preparation method of a chromium-free fingerprint-resistant liquid for aluminized zinc plates.

[0006] A preparation method of a chromium-free fingerprint-resistant liquid for aluminized zinc plates, in parts by weight, includes the following steps: S1. Preparation of the pretreatment solution: Mix 30 - 80 parts of deionized water with 0.1 - 10 parts of silane coupling agent KH550 and stir while keeping warm, then continue to add 0.1 - 10 parts of the composite corrosion inhibitor and stir while keeping warm, and finally let it stand and age for a certain time to obtain the pretreatment solution; S2. Construction of matrix resin composite system: Keep 1 - 10 parts of waterborne epoxy resin under warm stirring, then continue to add graphene oxide dispersion and keep stirring under warm condition. Next, add 0.1 - 10 parts of silane coupling agent KH560 and keep stirring under warm condition. Then, add 1 - 50 parts of nano-silica modified waterborne acrylic resin in three batches and keep stirring under warm condition. Continue to add 0.1 - 10 parts of nano-silica sol and keep stirring under warm condition. Then add 1 - 50 parts of waterborne polyurethane resin and keep stirring under warm condition. Finally, let it stand for a period of time to form a resin composite system; S3. Synthesis process of final product: Add the final pretreatment solution in step S1 above to the resin composite system finally prepared in step S2 above at a certain rate, stir for 10 - 15 minutes at a rotation speed of 40 - 50 revolutions per minute. Then, continue to add functional additives and 0.01 - 1 part of lanthanide rare earth - amino carboxylic acid composite anti - flash rust inhibitor in portions while stirring, with a rotation speed of 50 - 60 revolutions per minute for 25 - 35 minutes. Then, add 0.1 - 5 parts of pH regulator to adjust the pH value and carry out gradient constant - temperature curing to obtain the target product.

[0007] In step S1, mix deionized water and silane coupling agent KH550 and keep stirring under warm condition, with a rotation speed of 27 - 33 revolutions per minute, and stir under warm condition at 37 - 43 °C for 27 - 33 minutes. Then, continue to add the composite corrosion inhibitor and keep stirring, with a rotation speed of 55 - 65 revolutions per minute, and stir under warm condition at 33 - 37 °C for 10 - 15 minutes. Finally, let it stand for 23 - 25 hours. The composite corrosion inhibitor is a composite corrosion inhibitor of benzotriazole and cerium molybdate, and the mass ratio of benzotriazole to cerium molybdate is 3:(1 - 2).

[0008] In step S2, after adding waterborne epoxy resin, continue to stir under warm condition, with a rotation speed of 30 - 40 revolutions per minute, and stir under warm condition at 38 - 42 °C for 10 - 15 minutes. The ultrasonic frequency of the graphene oxide dispersion is 40 kHz and the dispersion time is 15 - 20 minutes. After adding silane coupling agent KH560, continue to stir under warm condition, with a rotation speed of 60 - 65 revolutions per minute, and stir under warm condition at 33 - 37 °C for 25 - 30 minutes. After adding nano - silica modified waterborne acrylic resin, continue to stir under warm condition, with a rotation speed of 40 - 45 revolutions per minute, and stir under warm condition at 33 - 37 °C for 10 - 15 minutes. Among them, the nano - silica modified waterborne acrylic resin is added in three - stage gradients, with an interval of 6 minutes each time. After adding nano - silica solution, continue to stir under warm condition, with a rotation speed of 60 - 65 revolutions per minute, and stir under warm condition at 33 - 37 °C for 10 - 15 minutes. Finally, add waterborne polyurethane and continue to stir under warm condition, with a rotation speed of 60 - 65 revolutions per minute, and stir under warm condition at 30 - 33 °C for 10 - 15 minutes. Finally, let it stand for 22 - 24 h under light - proof conditions to form a resin composite system.

[0009] In the step S3, the pretreatment liquid finally formed in the above step 1 is pumped into the resin composite system finally formed in the above step S2 at a rate of 2-3 mL / min, and stirred for 10-15 minutes at a rotation speed of 35-40 revolutions per minute; after continuously adding a lubricant, keep stirring with heat, the rotation speed is 40-45 revolutions per minute, and keep stirring with heat at 40-45 °C for 10-15 minutes; after continuously adding inorganic salts, keep stirring with heat, the rotation speed is 40-45 revolutions per minute, and keep stirring with heat at 40-45 °C for 10-15 minutes; after continuously adding a leveling agent, keep stirring with heat, the rotation speed is 40-45 revolutions per minute, and keep stirring with heat at 40-45 °C for 10-15 minutes; after continuously adding a film-forming auxiliary agent, keep stirring with heat, the rotation speed is 40-45 revolutions per minute, and keep stirring with heat at 40-45 °C for 10-15 minutes; after continuously adding a lanthanide rare earth-aminocarboxylic acid composite anti-flash rust agent, keep stirring with heat, the rotation speed is 60-65 revolutions per minute, and keep stirring with heat at 60-65 °C for 10-15 minutes, then continuously add a pH regulator and keep stirring with heat, the rotation speed is 30-35 revolutions per minute, and keep stirring with heat at 30-35 °C for 10-15 minutes, and finally obtain the target product through gradient constant temperature curing for 10-13 hours.

[0010] In the above step S1, the mass ratio of benzotriazole to cerium molybdate in the composite corrosion inhibitor is 3:(1-2), and further preferably 3:1.5; The present invention also discloses the preparation steps of the nano-silica modified waterborne acrylic resin in the above step S2 as follows, by weight: a. Mix nano-silica, ethanol, water and γ-methacryloxypropyltrimethoxysilane evenly, and carry out a water bath reflux reaction at 55-60 °C for 8-16 h, then cool to room temperature, and the product is centrifuged and washed to obtain silane coupling agent modified inorganic nanoparticles; b. Put 30-60 parts of water and 1-3 parts of emulsifier into a reactor and heat to 78-82 °C, then put 20-35 parts of alkyl acrylate monomer, 10-20 parts of hydroxyalkyl acrylate monomer, 5-10 parts of the silane coupling agent modified inorganic nanoparticles obtained in step a, 0.5-1 part of methacryloyloxyethyltrimethylammonium chloride, 3-5 parts of polyethylene glycol and 0.25-0.5 part of water-soluble initiator into the reactor, stir evenly, keep warm for 0.5-1 hour, then uniformly add 0.25-0.5 part of water-soluble initiator within 2 hours, and then keep warm for 4-8 hours and filter to obtain nano-silica modified waterborne acrylic resin.

[0011] In the above step a, the weight ratio of nano-silica, ethanol, water and γ-methacryloxypropyltrimethoxysilane is 1:(30-50):(5-15):(1-3), and further preferably 1:(35-45):(10-15):(2-3); The leveling agent is any one of BYK-348, BYK-3455, and BYK3410, and further preferably BYK-3410; The lubricant is any one of PE wax emulsion and OPE wax emulsion, and further preferably OPE wax emulsion; The inorganic salt is any one of vanadium salts, molybdenum salts, and zirconium salts, and further preferably molybdenum salts; The film-forming auxiliary agent is any one of ethylene glycol, propylene glycol, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, and dipropylene glycol monobutyl ether, and further preferably dipropylene glycol monomethyl ether; The pH regulator is any one of acetic acid, fluotitanic acid, and fluozirconic acid, and further preferably acetic acid; The present invention also discloses the preparation method of the lanthanide rare earth-amino carboxylic acid complex as the anti-flash rust agent in the step S3 as follows: Step 1. Solution preparation: Dissolve 1-1.5 parts of lanthanum nitrate hexahydrate in 6-10 parts of deionized water to prepare a salt solution; dissolve 0.5-1 part of ethylenediaminetetraacetic acid in 6-10 parts of deionized water to prepare a salt solution; Step 2. Coordination reaction: Stir at a rotation speed of 600-800 rpm for 20-30 minutes, add the rare earth salt solution prepared in the above step 1 to the prepared ethylenediaminetetraacetic acid solution, dropwise add an appropriate amount of sodium hydroxide solution to maintain the pH at 8-10, and stir at 60-80 °C for 6-8 hours to form a La-EDTA complex; Step 3. Precipitation, filtration, and drying: Precipitate and filter to obtain the La-EDTA complex in the above step 2, and continue to vacuum dry at 60-80 degrees Celsius for 6-8 hours to obtain a solid complex; Step 4. Functionalization treatment: Add 0.001-0.002 parts of surfactant SDS to the solid complex obtained in the above step 3, and continue to ultrasonically disperse for 10-30 minutes to obtain the final lanthanide rare earth-amino carboxylic acid complex.

[0012] The mass fraction of the surfactant SDS in the above step 4 is 0.1-0.2 wt%, and further preferably 0.1 wt%.

[0013] In summary, the present invention includes the following beneficial technical effects: 1. The present invention constructs a benzotriazole-cerium molybdate composite corrosion inhibition system, and forms a multi-layer adsorption film through intermolecular π-π stacking and rare earth ion coordination.

[0014] 2. The present invention introduces a graphene oxide / nano-silica synergistic enhancement system, the graphene sheets are oriented to form a physical barrier, and the nanoparticles fill the micropores to improve the density.

[0015] 3. The present invention uses lanthanide rare earth compounds to modify the anti-flash rust agent, and the characteristics of the empty orbitals of rare earth elements enhance the stability of the passivation film on the metal surface.

[0016] 4. The nano-material gradient dispersion process of the present invention combines ultrasonic-mechanical coupling dispersion technology to achieve uniform distribution of fillers and strengthening of interfacial bonding. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a comparison diagram of the 120-hour salt spray test on the surface of a galvanized-aluminum-zinc plate with a chromium-free fingerprint-resistant liquid prepared in Example 5 of the present invention and a surface treatment agent-coated galvanized-aluminum-zinc-magnesium steel plate prepared in Comparative Example 1 (the left side is the comparative example, and the right side is Example 5 of the present invention); Figure 2 is a comparison diagram of the high-temperature degreasing test on the surface of a galvanized-aluminum-zinc plate with a chromium-free fingerprint-resistant liquid prepared in Example 5 of the present invention and a surface treatment agent-coated galvanized-aluminum-zinc-magnesium steel plate prepared in Comparative Example 1 (the left side is the comparative example, and the right side is Example 5 of the present invention); Figure 3 is a comparison diagram of the 15-minute sweat test on the surface of a galvanized-aluminum-zinc plate with a chromium-free fingerprint-resistant liquid prepared in Example 5 of the present invention and a surface treatment agent-coated galvanized-aluminum-zinc-magnesium steel plate prepared in Comparative Example 1 (the left side is the comparative example, and the right side is Example 5 of the present invention); Figure 4 is a data sheet of the solution performance test of a chromium-free fingerprint-resistant liquid for galvanized-aluminum-zinc plates prepared by the present invention.

[0018] SOURCES OF RELATED SUBSTANCES

[0019] Graphene oxide dispersion liquid, product number: 1308124759-600, sourced from the independent reagent brand Klarmar reagent of Shanghai Kelaman Reagent Co., Ltd.

[0020] Other related substances are conventional substances of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0021] The following further elaborates on the present invention in conjunction with the attached Figures 1 to 4 for a more detailed description.

[0022] It should be noted that the drawings are schematic and not drawn to scale. For clarity and convenience in the figures, the relative sizes and proportions of the parts shown in the figures are exaggerated or reduced in size for illustration, and any dimensions are merely exemplary and not limiting. Additionally, the same reference numerals are used for the same structures, elements, or fittings that appear in more than two figures to represent similar features.

[0023] Example 1

[0024] A preparation method of a chromium-free fingerprint-resistant liquid for galvanized-aluminum-zinc plates, in parts by weight, includes the following steps: S1. Preparation of pretreatment solution: Mix 64.4 parts of deionized water with 1 part of silane coupling agent KH550, keep warm and stir, then continue to add 0.1 part of composite corrosion inhibitor and keep warm and stir. Finally, let it stand and age for a certain time to obtain the pretreatment solution; S2. Construction of matrix resin composite system: Keep 5 parts of waterborne epoxy resin warm and stir, then continue to add graphene oxide dispersion and keep warm and stir. Then continue to add 1 part of silane coupling agent KH560 and keep warm and stir. Add 15 parts of nano-silica modified waterborne acrylic resin in three batches and keep warm and stir. Then continue to add 1 part of nano-silica sol and keep warm and stir. Then continue to add 12 parts of waterborne polyurethane resin and keep warm and stir. Finally, let it stand for a period of time to form a resin composite system; S3. Synthesis process of final product: Add the final pretreatment solution in step S1 above to the resin composite system finally prepared in step S2 at a certain rate, stir for 10 - 15 minutes, with the stirring speed of 40 - 50 revolutions per minute. Then continue to add functional additives and 0.01 part of lanthanide rare earth - amino carboxylic acid composite anti - flash rust agent in portions, stir while adding, with the stirring speed of 50 - 60 revolutions per minute and the stirring time of 25 - 35 minutes. Then continue to add 0.1 part of pH regulator to adjust the pH value and carry out gradient constant - temperature curing to obtain the target product.

[0025] In step S1, mix deionized water with silane coupling agent KH550, keep warm and stir at a stirring rate of 30 revolutions per minute, keep warm at 40 °C for 30 minutes; after adding the composite corrosion inhibitor, keep warm and stir at a stirring speed of 60 revolutions per minute, keep warm and stir at 35 °C for 10 minutes, and finally let it stand for 24 hours for standby; In step S2, after adding waterborne epoxy resin, keep warm and stir at a stirring speed of 30 revolutions per minute, keep warm and stir at 35 °C for 10 minutes; the ultrasonic frequency of graphene oxide dispersion is 40 kHz and the dispersion time is 15 minutes; after adding silane coupling agent KH560, keep warm and stir at a stirring speed of 60 revolutions per minute, keep warm and stir at 35 °C for 30 minutes; after adding nano - silica modified waterborne acrylic resin, keep warm and stir at a stirring speed of 40 revolutions per minute, keep warm at 35 °C for 15 minutes, where the nano - silica modified waterborne acrylic resin is added in three - batch gradients with an interval of 6 minutes each time; then continue to add nano - silica sol and keep warm and stir at a stirring speed of 65 revolutions per minute, keep warm and stir at 35 °C for 10 minutes; finally add waterborne polyurethane and keep warm and stir at a stirring speed of 60 revolutions per minute, keep warm and stir at 30 °C for 10 minutes; finally let it stand for 24 h under light - proof conditions to form a resin composite system.

[0026] In the step S3, the pretreatment liquid finally formed in the above step 1 is pumped into the resin composite system finally formed in the above step S2 at a rate of 2 mL / min, stirred for 10 minutes at a rotation speed of 40 revolutions per minute; then a lubricant is added and stirring is continued while maintaining the temperature, the stirring speed is 40 revolutions per minute, and stirring is carried out at 40 °C for 10 minutes; then an inorganic salt is added and stirring is continued while maintaining the temperature, the stirring speed is 40 revolutions per minute, and stirring is carried out at 45 °C for 10 minutes; then a leveling agent is added and stirring is continued while maintaining the temperature, the stirring speed is 40 revolutions per minute, and stirring is carried out at 45 °C for 10 minutes; then a film-forming auxiliary agent is added and stirring is continued while maintaining the temperature, the stirring speed is 40 revolutions per minute, and stirring is carried out at 45 °C for 10 minutes; then a lanthanide rare earth-amino carboxylic acid composite anti-flash rust agent is added and stirring is continued while maintaining the temperature, the stirring speed is 60 revolutions per minute, and stirring is carried out at 60 °C for 10 minutes. Then a pH regulator is added and stirring is continued while maintaining the temperature, the stirring speed is 30 - 35 revolutions per minute, and stirring is carried out at 30 - 35 °C for 15 minutes. Finally, it is subjected to gradient constant temperature curing for 12 hours to obtain the target product.

[0027] The above functional auxiliaries are respectively 0.1 part of leveling agent BYK-3410, 0.1 part of lubricant OPE wax emulsion, 0.1 part of inorganic salt molybdenum salt, and 0.1 part of film-forming auxiliary agent dipropylene glycol monomethyl ether; In the composite corrosion inhibitor, the mass ratio of benzotriazole to cerium molybdate is 3:1.5; The preparation steps of the nano-silica modified waterborne acrylic resin in the above step S2 are as follows, by weight: a. Mix 1 part of nano-silica, 35 parts of ethanol, 15 parts of water and 2 parts of γ-methacryloxypropyltrimethoxysilane evenly, then carry out a reflux reaction in a water bath at 60 °C for 10 hours, and then cool to room temperature. The product is centrifuged and washed to obtain 3 parts of silane coupling agent modified inorganic nanoparticles; b. Put 45 parts of water and 2 parts of emulsifier into a reactor and heat to 80 °C, then put 27.5 parts of alkyl acrylate monomer, 15 parts of hydroxyalkyl acrylate monomer, 3 parts of the silane coupling agent modified inorganic nanoparticles obtained in the above step a, 0.75 part of methacryloxyethyltrimethylammonium chloride, 4 parts of polyethylene glycol and 0.4 part of water-soluble initiator into the reactor, stir evenly, keep warm for 0.5 - 1 hour, then add 0.4 part of water-soluble initiator uniformly within 2 hours, and then keep warm for 8 hours and filter to obtain the nano-silica modified waterborne acrylic resin.

[0028] The emulsifier is sodium dodecyl sulfate; the water-soluble initiator is ammonium persulfate; The present invention also discloses a preparation method of the lanthanide rare earth-amino carboxylic acid composite anti-flash rust agent in the above step S3, by weight: Step 1. Solution preparation: Dissolve 1 part of lanthanum nitrate hexahydrate in 7 parts of deionized water to prepare a salt solution; dissolve 0.7 part of ethylenediaminetetraacetic acid in 7 parts of deionized water to prepare a solution; Step 2. Coordination reaction: Stir for 30 minutes at a rotation speed of 800 rpm. Add the rare earth salt solution prepared in Step 1 above to the prepared ethylenediaminetetraacetic acid solution, dropwise add an appropriate amount of sodium hydroxide solution to maintain the pH at 8, and stir at 70 °C for 7 hours to form a La-EDTA complex; Step 3. Precipitation, filtration, and drying: Precipitate and filter to obtain the La-EDTA complex of Step 2 above, and continue to vacuum dry at 80 °C for 8 hours to obtain a solid complex; Step 4. Functionalization treatment: Add 0.001 part of a surfactant SDS with a mass fraction of 0.1 wt% to the solid complex obtained in Step 3 above, and continue to ultrasonically disperse for 20 minutes to obtain the final lanthanide rare earth-amino carboxylic acid complex.

[0029] Example 2

[0030] The difference between Example 2 and Example 1 is that, by weight, in Example 2, the waterborne epoxy resin is 6 parts, the waterborne acrylic resin is 16 parts, the waterborne polyurethane is 10 parts, 0.2 part of leveling agent BYK-3455, 0.2 part of lubricant OPE wax emulsion, 0.2 part of inorganic salt vanadium salt, 0.2 part of film-forming aid ethylene glycol, 0.5 part of silane coupling agent A is KH550, 0.5 part of silane coupling agent B, 0.2 part of corrosion inhibitor, 0.02 part of anti-flash rust agent, 0.5 part of nano-silicon solution, and 0.2 part of pH regulator acetic acid.

[0031] Example 3

[0032] The difference between Example 3 and Example 1 is that, by weight: 59.7 parts of deionized water, the waterborne epoxy resin is 7 parts, the waterborne acrylic resin is 17 parts, the waterborne polyurethane is 11 parts, 0.3 part of leveling agent BYK-348, 0.3 part of lubricant PE wax emulsion, 0.3 part of inorganic salt molybdenum salt, 0.3 part of film-forming aid propylene glycol, 1 part of silane coupling agent A is KH550, 1 part of silane coupling agent B KH560, 0.3 part of corrosion inhibitor, 0.03 part of anti-flash rust agent, 1.5 parts of nano-silicon solution, and 0.3 part of pH regulator acetic acid.

[0033] Example 4

[0034] Example 4 is different from Example 1 in that, by weight: 55.6 parts of deionized water, 8 parts of waterborne epoxy resin, 18 parts of waterborne acrylic resin, 12 parts of waterborne polyurethane, 0.4 part of leveling agent BYK-3410, 0.4 part of lubricant OPE wax emulsion, 0.4 part of inorganic salt molybdate, 0.4 part of film-forming auxiliary dipropylene glycol monomethyl ether, 1.5 parts of silane coupling agent A KH550, 1.5 parts of silane coupling agent B KH560, 0.4 part of corrosion inhibitor, 0.04 part of anti-flash rust agent, 1 part of nano-silicon solution, 0.4 part of pH regulator acetic acid.

[0035] Example 5

[0036] Example 5 is different from Example 1 in that, by weight: 53.5 parts of deionized water, 9 parts of waterborne epoxy resin, 19 parts of waterborne acrylic resin, 13 parts of waterborne polyurethane, 0.5 part of leveling agent BYK-3410, 0.5 part of lubricant OPE wax emulsion, 0.5 part of inorganic salt molybdate, 0.5 part of film-forming auxiliary dipropylene glycol monomethyl ether, 1 part of silane coupling agent A KH550, 1 part of silane coupling agent B KH560, 0.5 part of corrosion inhibitor, 0.05 part of anti-flash rust agent, 0.5 part of nano-silicon solution, 0.5 part of pH regulator acetic acid.

[0037] Example 6

[0038] Example 6 is different from Example 1 in that, by weight: 59.7 parts of deionized water, 7 parts of waterborne epoxy resin, 17 parts of waterborne acrylic resin, 11 parts of waterborne polyurethane, 0.3 part of leveling agent BYK-3410, 0.3 part of lubricant OPE wax emulsion, 0.3 part of inorganic salt molybdate, 0.3 part of film-forming auxiliary dipropylene glycol monoethyl ether, 1 part of silane coupling agent A KH550, 1 part of silane coupling agent B KH560, 0.3 part of corrosion inhibitor, 0.03 part of anti-flash rust agent, 1.5 parts of nano-silicon solution, 0.3 part of pH regulator fluotitanic acid.

[0039] Example 7

[0040] Example 7 is different from Example 1 in that, by weight: 44.8 parts of deionized water, 11 parts of waterborne epoxy resin, 21 parts of waterborne acrylic resin, 15 parts of waterborne polyurethane, 0.7 part of leveling agent BYK-3410, 0.7 part of lubricant OPE wax emulsion, 0.7 part of inorganic salt zirconate, 0.7 part of film-forming auxiliary dipropylene glycol monomethyl ether, 1.5 parts of silane coupling agent A KH550, 1.5 parts of silane coupling agent B KH560, 0.7 part of corrosion inhibitor, 0.07 part of anti-flash rust agent, 1 part of nano-silicon solution, 0.7 part of pH regulator fluozirconic acid.

[0041] Example 8

[0042] Example 8 is different from Example 1 in that, by weight: 43.7 parts of deionized water, 12 parts of waterborne epoxy resin, 22 parts of waterborne acrylic resin, 16 parts of waterborne polyurethane, 0.8 part of leveling agent BYK-3410, 0.8 part of lubricant OPE wax emulsion, 0.8 part of inorganic salt molybdate, 0.8 part of film-forming auxiliary dipropylene glycol monomethyl ether, 0.5 part of silane coupling agent A KH550, 0.5 part of silane coupling agent B KH560, 0.8 part of corrosion inhibitor, 0.08 part of anti-flash rust agent, 0.5 part of nano-silicon solution, 0.8 part of pH regulator acetic acid.

[0043] Comparative Example 1

[0044] CN1887449A A surface treatment agent for galvanized steel sheets.

[0045] Test items: Test item 1: Adhesion test

[0046] Test standard: The number 1 represents complete film peeling, the number 2 represents 50 - 80% film peeling, the number 3 represents 20 - 50% film peeling, the number 4 represents 5 - 15% film peeling, and the number 5 represents no film peeling at all; Table 1 Adhesion test results , As can be seen from Table 1 above, a chromium-free fingerprint-resistant liquid for aluminized zinc plates prepared in Example 5 effectively solves the problem of poor adhesion between the fingerprint-resistant coating and the substrate. The possible reasons are as follows: Different addition amounts and components affect the following aspects: 1. The dual role of silane coupling agents: The KH550 silane coupling agent used in the pretreatment step (S1) combines with the hydroxyl groups on the surface of the aluminized zinc plate through hydrolysis reaction to form chemical bonds, enhancing the interfacial bonding force; the KH560 silane coupling agent in the resin composite system (S2) further promotes the coupling of the resin and the nano-fillers, reducing interfacial defects; 2. Gradient dispersion of nano-fillers: The waterborne acrylic resin modified with nano-silica is added in three gradients, combined with the ultrasonic-mechanical coupling dispersion technology, to ensure the uniform distribution of nano-particles, reduce stress concentration, and enhance the mechanical interlocking effect between the film layer and the substrate; 3. The physical barrier effect of graphene oxide: The graphene oxide sheets are oriented to form a dense physical barrier to block the penetration of corrosive media, and at the same time its high specific surface area enhances the adhesion between the resin and the substrate.

[0047] Test item 2: Color difference in ultrasonic alkali test

[0048] Test conditions: The color difference is measured after spraying with medium-alkaline degreaser (Ph = 12, 50 °C, 3 min); Test standard: The number 1 represents complete film peeling, the number 2 represents color difference > 5, the number 3 represents color difference 3 - 5, the number 4 represents color difference < 3, and the number 5 represents no color difference at all; A color difference grade of ≥4 is judged as qualified; Table 2 Color difference results of ultrasonic alkali test , As can be seen from Table 2 above, Example 5 has the best color difference. The possible reasons are as follows: The addition and proportion of different components will affect the following aspects: 1. Multilayer adsorption protection of the composite corrosion inhibitor system: Benzotriazole is adsorbed on the metal surface through π-π stacking, and cerium molybdate forms a stable complex through rare earth ion coordination. The two cooperate to construct a multilayer adsorption film to inhibit metal oxidation and film layer shedding in an alkaline environment; 2. Stability of the lanthanide rare earth passivation film: The La-EDTA composite anti-flash rust inhibitor binds to the metal surface through the characteristics of rare earth empty orbitals to form a dense passivation film, improving alkali resistance; 3. Filling effect of nano-silica sol: Nano-silica sol fills the micropores of the film layer, reducing the erosion path of alkaline solution to the substrate.

[0049] Test item 3: Corrosion resistance test

[0050] Test conditions: ISO 9227-2022, 120-hour neutral salt spray test; Table 3 Corrosion resistance test results , As can be seen from Table 3 above, the aluminized zinc plate without chromium anti-fingerprint solution prepared in Example 5 has the best corrosion resistance. Figure 1 Figure for the comparison of the 120-hour salt spray test between Example 5 and Comparative Example 1. It can be seen that the corrosion resistance of Example 5 is better. The possible reasons are as follows: The addition and proportion of different components will affect the following aspects: 1. Synergistic effect of the composite corrosion inhibitor: The compound corrosion inhibitor system of benzotriazole (BTA) and cerium molybdate forms a multilayer adsorption film on the metal surface. BTA inhibits the anodic reaction, and cerium molybdate promotes cathodic passivation, significantly reducing the corrosion rate; 2. Synergistic enhancement of graphene oxide / nano-silica: The graphene oxide sheets block the penetration of corrosive media, and nano-silica fills the micro-defects of the film layer. The two cooperate to improve the denseness of the film layer; 3. Role of rare earth modified anti-flash rust inhibitor: The La-EDTA complex forms a stable passivation film on the metal surface, inhibiting pitting corrosion and electrochemical corrosion.

[0051] Test item 4: High-temperature degreasing test

[0052] Take an aluminized zinc-magnesium steel plate of 200mm×300mm×1mm, after degreasing, water washing, pure water washing, drying, coating the passivation liquid of the above examples and comparative examples, drying (70-100°C), and placing at room temperature, and perform performance testing on the steel plate after treatment; Perform high-temperature degreasing test on the best Example 5 and Comparative Example 1, and the test results are as Figure 2As shown; compared with Comparative Example 1, the corrosion resistance of a chromium-free fingerprint-resistant liquid for aluminized zinc plates prepared in Example 5 of the present invention when coated on an aluminized zinc plate is better. The possible reasons are as follows: 1. Thermal stability of the resin system: The composite system of waterborne epoxy resin and polyurethane resin has a relatively high thermal decomposition temperature, and the film structure is not easily damaged at high temperatures; 2. Reinforcement effect of nano-fillers: The high thermal conductivity of nano-silica and graphene oxide disperses local heat and reduces film cracking caused by thermal stress; 3. Crosslinking network of silane coupling agents: KH550 and KH560 are further crosslinked at high temperatures, enhancing the interfacial bonding strength between the film layer and the substrate.

[0053] Test Item 5: Comparative Test of Sweat Experiment

[0054] Take an aluminized zinc-magnesium steel plate with dimensions of 200mm×300mm×1mm, degrease, wash with water, wash with pure water, dry, coat with the passivation liquid of the above examples and comparative examples, dry (70-100°C), and place at room temperature. After treatment, perform performance testing on the steel plate; Figure 3 This is the comparative diagram of the 15-minute sweat experiment of Example 5 of the present invention and Comparative Example 1; compared with Comparative Example 1, the corrosion resistance of a chromium-free fingerprint-resistant liquid for aluminized zinc plates prepared in Example 5 of the present invention when coated on an aluminized zinc plate has better sweat resistance. The possible reasons are as follows: 1. Dual protection of hydrophobicity and denseness: Silane coupling agents and nano-silica endow the film layer with hydrophobicity, reducing sweat penetration; the physical barrier of graphene oxide further blocks electrolytes in sweat; 2. Chemical passivation of the composite corrosion inhibitor: BTA competes for adsorption with Cl - in sweat, and cerium molybdate inhibits the dissolution of metal ions, reducing the risk of electrochemical corrosion.

[0055] Test Item 6: Solution Performance Test

[0056] Take an aluminized zinc-magnesium steel plate with dimensions of 200mm×300mm×1mm, degrease, wash with water, wash with pure water, dry, coat with the passivation liquid of the above examples and comparative examples, dry (70-100°C), and place at room temperature. After treatment, perform performance testing on the steel plate; Perform solution performance testing on Example 5 of the present invention and Comparative Example 1. The test standards and results are as Figure 4As shown; compared with Comparative Example 1, the corrosion resistance of a chromium-free fingerprint-resistant liquid for aluminized zinc plates prepared in Example 5 of the present invention, when coated on the aluminized zinc plate, has an obviously shortened curing time, enhanced hardness, stronger salt spray resistance, and reduced viscosity. The possible reasons are as follows: 1. Uniform dispersion and interfacial strengthening of nano-fillers: The ultrasonic-mechanical coupling dispersion technology realizes the uniform distribution of nano-particles, reduces agglomeration, accelerates the curing reaction and improves the crosslinking density; 2. Catalytic effect of lanthanide rare earths: The La-EDTA complex promotes the resin crosslinking reaction, shortens the curing time, and at the same time enhances the hardness of the film layer; 3. Optimization of the gradient curing process: Gradient isothermal curing (Step S3) enables the resin to be fully crosslinked, forming a dense network structure and improving the salt spray resistance performance.

[0057] In Example 5, through the design of a composite corrosion inhibition system (benzotriazole-cerium molybdate), the synergistic enhancement of nanomaterials (graphene oxide / nano-silica), the modification of rare earth anti-flash rust agents (La-EDTA), and the gradient dispersion process, the adhesion, corrosion resistance, alkali resistance, and high-temperature stability of the film layer have been significantly improved. Its technical advantages mainly stem from the multi-component synergistic effect and the strengthening of interfacial bonding, which conforms to the current trend of high-performance chromium-free fingerprint-resistant liquids.

[0058] The standard parts used in the present invention can all be purchased from the market. The special-shaped parts can be customized according to the description in the specification and the drawings. The specific connection methods of each part all adopt conventional means such as bolts, rivets, and welding that are mature in the prior art. The machinery, parts, and equipment all adopt conventional models in the prior art. Coupled with the circuit connection adopting the conventional connection method in the prior art, it will not be elaborated here.

[0059] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A preparation method of a chromium-free fingerprint-resistant solution for aluminized zinc plate, characterized in that, Comprising the following steps by weight parts: S1. Preparation of pretreatment solution: Mix 30 - 80 parts of deionized water with 0.1 - 10 parts of silane coupling agent KH550, keep warm and stir, then continue to add 0.1 - 10 parts of composite corrosion inhibitor, keep warm and stir, and finally stand for aging for a certain time to obtain the pretreatment solution; S2. Construction of matrix resin composite system: Keep 1 - 10 parts of waterborne epoxy resin warm and stir, then continue to add graphene oxide dispersion and keep warm and stir, then continue to add 0.1 - 10 parts of silane coupling agent KH560 and keep warm and stir, add 1 - 50 parts of nano-silica modified waterborne acrylic resin in three batches and keep warm and stir, then continue to add 0.1 - 10 parts of nano-silica sol and keep warm and stir, then continue to add 1 - 50 parts of waterborne polyurethane resin and keep warm and stir, and finally stand for a period of time to form a resin composite system; S3. Final product synthesis process: Add the final pretreatment solution in step S1 above to the resin composite system finally prepared in step S2 at a certain rate, stir for 10 - 15 minutes at a rotation speed of 40 - 50 revolutions per minute, continue to add functional additives and 0.01 - 1 part of lanthanide rare earth - amino carboxylic acid composite anti-flash rust agent in batches, stir while adding at a rotation speed of 50 - 60 revolutions per minute, stir for 25 - 35 minutes, then continue to add 0.1 - 5 parts of pH regulator to adjust the pH value and carry out gradient constant temperature curing to obtain the target product.

2. The preparation method of a chromium-free fingerprint-resistant solution for aluminized zinc plate according to claim 1, characterized in that: In step S1, the deionized water and silane coupling agent KH550 are mixed and stirred while keeping warm at a rotation speed of 27 - 33 revolutions per minute, and stirred while keeping warm at 37 - 43 °C for 27 - 33 minutes; after adding the composite corrosion inhibitor, continue to stir while keeping warm at a rotation speed of 55 - 65 revolutions per minute, and stirred while keeping warm at 33 - 37 °C for 10 - 15 minutes; the composite corrosion inhibitor is a composite corrosion inhibitor of benzotriazole and cerium molybdate, and the mass ratio of benzotriazole to cerium molybdate is 3:(1 - 2).

3. The preparation method of a chromium-free fingerprint-resistant solution for aluminized zinc plate according to claim 1, characterized in that: In step S2, after adding the waterborne epoxy resin, continue to stir while keeping warm at a rotation speed of 30 - 40 revolutions per minute, and stirred while keeping warm at 38 - 42 °C for 10 - 15 minutes; the ultrasonic frequency of the graphene oxide dispersion is 40 kHz, and the dispersion time is 15 - 20 minutes; after adding the silane coupling agent KH560, continue to stir while keeping warm at a rotation speed of 60 - 65 revolutions per minute, and stirred while keeping warm at 33 - 37 °C for 25 - 30 minutes; after adding the nano-silica modified waterborne acrylic resin, continue to stir while keeping warm at a rotation speed of 40 - 45 revolutions per minute, and stirred while keeping warm at 33 - 37 °C for 10 - 15 minutes; among them, the nano-silica modified waterborne acrylic resin is added in three gradient batches, with an interval of 6 minutes each time; continue to add the nano-silica sol and stir while keeping warm at a rotation speed of 60 - 65 revolutions per minute, and stirred while keeping warm at 33 - 37 °C for 10 - 15 minutes; finally, after adding the waterborne polyurethane, continue to stir while keeping warm at a rotation speed of 60 - 65 revolutions per minute, and stirred while keeping warm at 30 - 33 °C for 10 - 15 minutes; finally, stand in the dark for 22 - 24 hours to form a resin composite system.

4. The preparation method of a chromium-free fingerprint-resistant solution for aluminized zinc plate according to claim 1, characterized in that: In the step S3, the pretreatment liquid finally formed in the above step 1 is pumped into the resin composite system finally formed in the above step S2 at a rate of 2-3 mL / min, and stirred for 10-15 minutes at a rotation speed of 35-40 revolutions per minute; after continuously adding a lubricant, keep stirring while heating, with a rotation speed of 40-45 revolutions per minute, and keep stirring at 40-45 °C for 10-15 minutes; after continuously adding an inorganic salt, keep stirring while heating, with a rotation speed of 40-45 revolutions per minute, and keep stirring at 40-45 °C for 10-15 minutes; after continuously adding a leveling agent, keep stirring while heating, with a rotation speed of 40-45 revolutions per minute, and keep stirring at 40-45 °C for 10-15 minutes; after continuously adding a film-forming auxiliary agent, keep stirring while heating, with a rotation speed of 40-45 revolutions per minute, and keep stirring at 40-45 °C for 10-15 minutes; after continuously adding a lanthanide rare earth-aminocarboxylic acid composite anti-flash rust agent, keep stirring while heating, with a rotation speed of 60-65 revolutions per minute, and keep stirring at 60-65 °C for 10-15 minutes; after continuously adding a pH regulator, keep stirring while heating, with a rotation speed of 30-35 revolutions per minute, and keep stirring at 30-35 °C for 10-15 minutes, and finally obtain the target product through gradient constant temperature curing for 10-13 hours.

5. The preparation method of a chromium-free fingerprint-resistant solution for aluminized zinc plate according to claim 1, characterized in that, In the step S2, the preparation steps of the nano-silica modified waterborne acrylic resin are as follows, by weight: a. Mix nano-silica, ethanol, water and γ-methacryloxypropyltrimethoxysilane evenly, and carry out a water bath reflux reaction at 55-60 °C for 8-16 hours, then cool to room temperature, and the product is centrifuged and washed to obtain silane coupling agent modified inorganic nanoparticles; b. Put 30-60 parts of water and 1-3 parts of emulsifier into a reactor and heat to 78-82 °C, then put 20-35 parts of alkyl acrylate monomer, 10-20 parts of hydroxyalkyl acrylate monomer, 5-10 parts of the silane coupling agent modified inorganic nanoparticles obtained in step a, 0.5-1 part of methacryloxyethyltrimethylammonium chloride, 3-5 parts of polyethylene glycol and 0.25-0.5 part of water-soluble initiator into the reactor, stir evenly, keep warm for 0.5-1 hour, add 0.25-0.5 part of water-soluble initiator uniformly within 2 hours, and then keep warm for 4-8 hours and filter to obtain nano-silica modified waterborne acrylic resin.

6. The preparation method of a chromium-free fingerprint-resistant solution for aluminized zinc plate according to claim 5, characterized in that: By weight, the dosage ratio of nano-silica, ethanol, water and γ-methacryloxypropyltrimethoxysilane in the above step a is 1:(30-50):(5-15):(1-3).

7. The preparation method of a chromium-free fingerprint-resistant solution for aluminized zinc plate according to claim 4, characterized in that: The leveling agent is any one of BYK-348, BYK-3455, BYK3410; the lubricant is any one of PE wax emulsion, OPE wax emulsion; the inorganic salt is any one of vanadium salt, molybdenum salt, zirconium salt; the film-forming auxiliary agent is any one of ethylene glycol, propylene glycol, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether; the pH regulator is any one of acetic acid, fluotitanic acid, fluorozirconic acid.

8. The preparation method of a chromium-free fingerprint-resistant solution for aluminized zinc plate according to claim 1, characterized in that, In the step S3, the preparation method of the anti-flash rust agent lanthanide rare earth-aminocarboxylic acid complex is as follows, by weight: Step 1. Solution preparation: Dissolve 1 - 1.5 parts of lanthanum nitrate hexahydrate in 6 - 10 parts of deionized water to prepare a salt solution; dissolve 0.5 - 1 part of ethylenediaminetetraacetic acid in 6 - 10 parts of deionized water to prepare a salt solution; Step 2. Coordination reaction: Stir at a rotation speed of 600 - 800 rpm for 20 - 30 minutes, add the rare earth salt solution prepared in Step 1 above to the prepared ethylenediaminetetraacetic acid solution, dropwise add an appropriate amount of sodium hydroxide solution to maintain the pH at 8 - 10, and stir at 60 - 80 °C for 6 - 8 hours to form a La-EDTA complex; Step 3. Precipitation, filtration, and drying: Precipitate and filter to obtain the La-EDTA complex in Step 2 above, and continue to vacuum dry at 60 - 80 °C for 6 - 8 hours to obtain a solid complex; Step 4. Functionalization treatment: Add 0.001 - 0.002 parts of surfactant SDS to the solid complex obtained in Step 3 above, and continue ultrasonic dispersion for 10 - 30 minutes to obtain the final lanthanide rare earth - aminocarboxylic acid complex.

9. The preparation method of a chromium-free fingerprint-resistant solution for aluminized zinc plate according to claim 8, characterized in that: The mass fraction of surfactant SDS in Step 4 above is 0.1 - 0.2 wt%.

10. The preparation method of a chromium-free fingerprint-resistant solution for aluminized zinc plate according to any one of claims 1-9, characterized in that: The target product does not contain chromium elements and has excellent fingerprint resistance, corrosion resistance, and blackening resistance.

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