Preparation method of epoxy acrylate metal coating based on gradient photocuring
By using a gradient photocuring process and specific component compounding, a dense hydrophobic layer and a slow-release anti-corrosion layer are formed, which solves the cracking and corrosion problems of epoxy acrylate coatings in humid and hot environments and achieves long-term protective effect.
Patent Information
- Application Number
- CN202511712274.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-20
- Publication Date
- 2026-03-03
AI Technical Summary
Traditional epoxy acrylate coatings are prone to cracking and reduced corrosion resistance in harsh, humid and hot environments. Existing improvement methods are difficult to balance hardness, toughness, and production efficiency. Furthermore, uneven dispersion of anti-corrosion components leads to defects, and uneven distribution of slow-release materials in the coating makes it impossible to achieve long-term corrosion protection.
A gradient photocuring process is adopted, including pre-curing, main curing and post-curing steps. It combines alkyl ketene dimer hydrophobic agent and sodium alginate slow-release microspheres to form a dense hydrophobic layer and a slow-release anti-corrosion layer through photocuring with different wavelengths and energies, thereby synergistically improving the coating performance.
No cracking was observed after more than 5,000 hours of salt spray testing and after thermal cycling. The wear resistance and adhesion were significantly enhanced, solving the problem of long-term protection of metal substrate coatings in humid and hot environments.
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Abstract
Description
Technical Field
[0001] This invention provides a method for preparing epoxy acrylate metal coatings based on gradient photocuring, which relates to the field of epoxy acrylate metal coating technology. Background Technology
[0002] Epoxy acrylate coatings, combining the high adhesion and hardness of epoxy resins with the excellent photocuring activity of acrylates, are widely used in metal protection applications, such as the external surface protection of marine equipment like ship decks and offshore platform supports, and the internal coating of chemical carbon steel pipelines transporting corrosive media like sulfuric acid and sodium hydroxide. However, these traditional coatings are prone to internal stress cracking and a sharp drop in corrosion resistance in harsh, humid, and hot environments. In marine environments, salt spray concentrations often reach 5% NaCl solution standards, relative humidity remains above 90%, and temperature fluctuations range from 10-40°C. Chemical pipelines, on the other hand, face immersion in 30%-50% concentrations of acid and alkali media and sustained high temperatures of 40-60°C. Under such conditions, the cracking rate of coatings can rise to over 30% within 6 months, with corrosion failure rates exceeding 40%. The core reason for this problem lies in the significant difference in the coefficients of thermal expansion between the metal substrate and the coating: the coefficient of thermal expansion of commonly used carbon steel substrates is approximately 12 × 10⁻⁶. -6 / ℃, the aluminum alloy substrate is approximately 23×10 -6 / ℃, while the coefficient of thermal expansion of epoxy acrylate coating is as high as 60×10. -6The difference in expansion and contraction between the two materials due to temperature variations (e.g., ℃) easily generates interfacial stress. Simultaneously, the rapid cross-linking of molecular chains during coating curing prevents them from fully relaxing, leading to a significant accumulation of internal stress within the coating and ultimately causing microcracks that become channels for corrosive media intrusion. While existing technologies attempt to improve this by adding toughening agents or adjusting the curing process, the effects are limited: adding toughening agents such as carboxyl-terminated nitrile rubber can increase the coating's elongation at break from 2%-3% to 5%-7%, but additions exceeding 10% cause the coating hardness to drop from Shore D85 to below D70, resulting in a 20% decrease in abrasion resistance. Adjusting the curing process, such as using segmented UV curing with low-strength pre-curing and high-strength full curing, can reduce internal stress by 15%-20%, but it reduces production efficiency by 30%, making it unsuitable for continuous industrial production. Furthermore, conventional UV curing processes have inherent flaws; excessively rapid curing rates can exceed the coating's stress tolerance limits, triggering microcracks. These microcracks gradually expand in humid and hot environments, further exacerbating the decline in corrosion resistance. In terms of corrosion protection, traditional coatings often rely on single anti-corrosion components such as zinc phosphate. However, zinc phosphate is prone to agglomeration due to uneven dispersion in the coating, leading to protective gaps. Furthermore, zinc phosphate dissolves rapidly in acidic environments; in a simulated chemical wastewater environment with a pH of 3, the dissolution rate reaches 40% within 100 days, making long-term corrosion protection impossible. In recent years, although some studies have introduced cross-domain components to improve performance, such as alkyl ketone dimers commonly used in the paper industry, which can form a hydrophobic layer on the coating surface, increasing the water contact angle from 70° to over 100° and reducing water adhesion, AKD has poor compatibility with epoxy acrylates. Adding more than 3% will cause coating delamination and decreased adhesion. Another example is sodium alginate microspheres, a slow-release material in the pharmaceutical field, which can encapsulate corrosion inhibitors such as benzotriazole for slow release. However, because it is not combined with gradient photocuring technology, the microspheres are unevenly distributed in the coating, with the initial release of corrosion inhibitors reaching 60%, but the later release amount being less than 10%, failing to form a sustained anti-corrosion effect. These technical defects ultimately resulted in poor coating performance in harsh environmental tests: after thermal cycling tests from -40℃ to 150℃, the coating cracking rate exceeded 60%, with cracks concentrated at the interface between the coating and the substrate and at internal stress concentration points; in neutral salt spray tests, the coating life was less than 2000 hours, and after 2000 hours, the blistering rate on the coating surface reached 50%, and the rust area of the metal substrate exceeded 30%, which is far from meeting the long-term durability requirements of marine equipment and chemical pipelines. Summary of the Invention
[0003] To address the aforementioned problems, this invention provides a method for preparing an epoxy acrylate metal coating based on gradient photocuring, comprising the following steps: coating an epoxy acrylate metal coating onto a metal substrate with a coating thickness of 10μm-100μm, and then performing gradient photocuring, wherein the gradient photocuring includes pre-curing, main curing, and post-curing steps.
[0004] Preferably, the pre-curing step uses a UV-A light source with a wavelength of 320nm-390nm and a light intensity of 50mWh / cm². 2 -100mWh / cm 2 The exposure time is 10s-30s.
[0005] Preferably, the main curing step uses a UV-C light source with a wavelength of 250nm-260nm and a light intensity of 200mWh / cm². 2 -300mWh / cm 2 The exposure time is 5s-15s.
[0006] Preferably, the post-curing step uses a visible light LED light source with a wavelength of 450 nm and a light intensity of 80 mWh / cm². 2 -120mWh / cm 2 Simultaneously heat to 80℃-100℃ for 10min-30min.
[0007] Preferably, the metal substrate is one of steel, aluminum or copper, and surface treatment is required before coating, including sanding, degreasing and drying. Sanding is done with sandpaper with a grit of 400-600 mesh, degreasing is done with acetone or ethanol solvent, drying temperature is 60℃-80℃, and drying time is 10min-20min.
[0008] Preferably, in the gradient photocuring step, UV-reversible color-changing spiropyran may be added as a stress indicator, with an addition amount of 0.01%-0.1% of the total mass of the coating, and / or polydimethylsiloxane microemulsion may be added as a release agent, with an addition amount of 0.5%-2% of the total mass of the coating.
[0009] Preferably, the coating method is one of spraying, brushing or roller coating, and after coating, it needs to be leveled at room temperature for 1-5 minutes before gradient light curing.
[0010] Preferably, the epoxy acrylate metal coating comprises the following components: epoxy acrylate resin, reactive diluent, photoinitiator, anti-corrosion pigment, additives, hydrophobic agent, and slow-release microspheres.
[0011] Preferably, the hydrophobic agent is an alkyl ketene dimer, added at 0.5%-5% of the total mass of the coating; the slow-release microspheres are sodium alginate gel microspheres, added at 1%-10% of the total mass of the coating, and the particle size of the sodium alginate gel microspheres is 1μm-50μm; the epoxy acrylate resin is added at 30%-60% of the total mass of the coating; and the reactive diluent is at least one of trimethylolpropane triacrylate or 1,6-hexanediol diacrylate, added at 10%-30% of the total mass of the coating. The photoinitiator is at least one of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide or phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, and the addition amount is 1%-5% of the total mass of the coating. The anti-corrosion pigment is zinc phosphate, and the addition amount is 5%-20% of the total mass of the coating. The additives include leveling agents and defoamers. The leveling agent is polyether-modified polydimethylsiloxane, and the addition amount is 0.1%-1% of the total mass of the coating. The defoamer is polysiloxane emulsion, and the addition amount is 0.1%-1% of the total mass of the coating.
[0012] Preferably, the coating may further include abrasion-resistant filler, which is alumina micro powder, added at 5%-15% of the total mass of the coating, and the particle size of the alumina micro powder is 0.5μm-5μm.
[0013] Preferably, the coating may further include an antistatic agent, which is a polyether ester amide, and the amount added is 1%-5% of the total mass of the coating.
[0014] Preferably, the preparation method of the epoxy acrylate metal coating includes the following steps: mixing epoxy acrylate resin, reactive diluent, photoinitiator, anti-corrosion pigment, additives, hydrophobic agent and slow-release microspheres at room temperature, and then stirring at 500 rpm-1000 rpm for 30 min-60 min until the mixture is uniform.
[0015] Preferably, the mixing step is carried out under light-protected conditions, and after mixing, the mixture needs to be allowed to stand for degassing. The standing time is 10 min to 30 min, and the degassing is carried out using a vacuum degassing machine with a vacuum degree of -0.095 MPa to 0.1 MPa and a degassing time of 5 min to 15 min.
[0016] The beneficial effects of this invention are as follows:
[0017] This invention combines alkyl ketene dimer hydrophobic agents and sodium alginate slow-release microspheres into epoxy acrylate coatings, and uses a three-stage gradient photocuring process. During the pre-curing stage, the hydrophobic agent migrates to the coating surface to form a dense hydrophobic layer. The slow-release microspheres absorb moisture and release anti-corrosion ions during the main curing stage, and alleviate internal stress during the post-curing stage. This synergistically improves the coating's resistance to humid heat aging and cracking. After salt spray testing exceeding 5000 hours and thermal cycling, no cracking was observed, and wear resistance and adhesion were significantly enhanced, solving the problem of long-term protection for metal substrate coatings in humid and hot environments. Detailed Implementation
[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.
[0020] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the experimental materials used in the following examples are all purchased from commercial channels.
[0021] Example 1
[0022] To prepare an epoxy acrylate metallic coating, the following components were prepared by mass percentage: 50% epoxy acrylate resin, 20% trimethylolpropane triacrylate, 3% 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 10% zinc phosphate, 0.5% polyether-modified polydimethylsiloxane leveling agent, 0.5% polysiloxane defoamer, 2% alkyl ketene dimer, and 5% sodium alginate gel microspheres (particle size 10 μm). The remainder was deionized water as solvent. The mixture was stirred at 800 rpm for 40 min at room temperature, and allowed to stand for 20 min to remove bubbles (vacuum degree -0.098 MPa) to obtain the coating. A Q235 steel substrate was sanded (using 500-grit sandpaper), degreased (with acetone), and dried (70℃, 15 min). The coating was then sprayed onto the substrate to a thickness of 50 μm, leveled for 3 min, and then subjected to gradient light curing. Pre-curing was performed using a UV-A lamp (wavelength 350 nm, light intensity 75 mW / cm²). 2 Exposure for 20 seconds), main curing with a UV-C lamp (wavelength 255nm, light intensity 250mW / cm²). 2Exposure for 10 seconds, followed by curing with a visible light LED (wavelength 450nm, light intensity 100mW / cm²). 2 Heat at 90℃ for 20 minutes.
[0023] Example 2
[0024] To prepare an epoxy acrylate metallic coating, the following components were prepared by mass percentage: 40% epoxy acrylate resin, 25% 1,6-hexanediol diacrylate, 4% phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, 15% zinc phosphate, 0.3% polyether-modified polydimethylsiloxane leveling agent, 0.3% polysiloxane defoamer, 3% alkyl ketene dimer, and 8% sodium alginate gel microspheres (particle size 20 μm). The remainder was deionized water as the solvent. The mixture was stirred at 500 rpm for 60 min at room temperature until homogeneous. Then, allow the mixture to stand for 10 minutes to degas using a vacuum degassing machine at a vacuum degree of -0.095 MPa to obtain the coating. The Q235 steel substrate undergoes surface treatment, including sanding with 400-mesh sandpaper, degreasing with ethanol solvent, and drying at 60℃ for 20 minutes. The coating is then applied by brush to a thickness of 30 μm. After coating, it is leveled at room temperature for 5 minutes, followed by gradient light curing: the pre-curing step uses a UV-A light source with a wavelength of 320 nm and a light intensity of 50 mWh / cm². 2 The exposure time was 30 seconds, and the main curing step used a UV-C light source with a wavelength of 250 nm and a light intensity of 200 mWh / cm². 2 The exposure time was 15 seconds, and the post-curing step used a visible light LED light source with a wavelength of 450 nm and a light intensity of 80 mWh / cm². 2 Simultaneously heat to 80℃ for 30 minutes.
[0025] Example 3
[0026] To prepare an epoxy acrylate metallic coating, the following components were prepared by mass percentage: 50% epoxy acrylate resin, 20% trimethylolpropane triacrylate, 3% 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 10% zinc phosphate, 0.5% polyether-modified polydimethylsiloxane leveling agent, 0.5% polysiloxane defoamer, 2% alkyl ketene dimer, 5% sodium alginate gel microspheres (particle size 10 μm), and 10% alumina microparticles (particle size 0.5 μm). The remainder was deionized water as solvent. The mixture was stirred at 1000 rpm for 30 minutes at room temperature. Mix thoroughly until homogeneous, then allow to stand for 30 minutes to degas. Degassing is performed using a vacuum degassing machine at a vacuum degree of -0.1 MPa to obtain the coating. The Q235 steel substrate undergoes surface treatment, including sanding with 600-mesh sandpaper, degreasing with acetone solvent, and drying at 80℃ for 10 minutes. The coating is then applied by spraying to a thickness of 50 μm. After coating, leveling is performed at room temperature for 1 minute, followed by gradient light curing: the pre-curing step uses a UV-A light source with a wavelength of 390 nm and a light intensity of 100 mWh / cm². 2 The exposure time was 10 seconds, and the main curing step used a UV-C light source with a wavelength of 260 nm and a light intensity of 300 mWh / cm². 2 The exposure time was 5 seconds, and the post-curing step used a visible light LED light source with a wavelength of 450 nm and a light intensity of 120 mWh / cm². 2 Simultaneously heat to 100℃ for 10 minutes.
[0027] Comparative Example 1 (The coating does not contain alkyl ketene dimers)
[0028] To prepare an epoxy acrylate metallic coating, the following components were prepared by mass percentage: 50% epoxy acrylate resin, 20% trimethylolpropane triacrylate, 3% 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 10% zinc phosphate, 0.5% polyether-modified polydimethylsiloxane leveling agent, 0.5% polysiloxane defoamer, and 5% sodium alginate gel microspheres (particle size 10 μm). The remainder was deionized water as solvent. No alkyl ketene dimers were added. The mixture was stirred at 800 rpm for 40 min at room temperature until homogeneous. Then, the mixture was allowed to stand for 20 minutes to remove air bubbles using a vacuum degassing machine at a vacuum degree of -0.098 MPa, resulting in the coating. The Q235 steel substrate underwent surface treatment, including sanding with 500-mesh sandpaper, degreasing with acetone solvent, and drying at 70℃ for 15 minutes. The coating was then applied by spraying to a thickness of 50 μm. After coating, it was allowed to level at room temperature for 3 minutes, followed by gradient light curing: the pre-curing step used a UV-A light source with a wavelength of 350 nm and a light intensity of 75 mWh / cm². 2 The exposure time was 20 seconds, and the main curing step used a UV-C light source with a wavelength of 255 nm and a light intensity of 250 mWh / cm².2 The exposure time was 10 seconds, and the post-curing step used a visible light LED light source with a wavelength of 450 nm and a light intensity of 100 mWh / cm². 2 Simultaneously heat to 90℃ for 20 minutes.
[0029] Comparative Example 2 (Coating without sodium alginate microspheres)
[0030] To prepare an epoxy acrylate metallic coating, the following components were prepared by mass percentage: 50% epoxy acrylate resin, 20% trimethylolpropane triacrylate, 3% 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 10% zinc phosphate, 0.5% polyether-modified polydimethylsiloxane leveling agent, 0.5% polysiloxane defoamer, and 2% alkyl ketene dimer. The remainder was deionized water as solvent. Sodium alginate gel microspheres were not added. The mixture was stirred at 800 rpm for 40 minutes at room temperature until homogeneous, and then allowed to stand. The coating was degassed for 20 minutes using a vacuum degassed machine at a vacuum degree of -0.098 MPa to obtain the coating material. The Q235 steel substrate underwent surface treatment, including sanding with 500-mesh sandpaper, degreasing with acetone solvent, and drying at 70℃ for 15 minutes. The coating was then applied by spraying to a thickness of 50 μm. After coating, it was leveled at room temperature for 3 minutes, followed by gradient light curing: the pre-curing step used a UV-A light source with a wavelength of 350 nm and a light intensity of 75 mWh / cm². 2 The exposure time was 20 seconds, and the main curing step used a UV-C light source with a wavelength of 255 nm and a light intensity of 250 mWh / cm². 2 The exposure time was 10 seconds, and the post-curing step used a visible light LED light source with a wavelength of 450 nm and a light intensity of 100 mWh / cm². 2 Simultaneously heat to 90℃ for 20 minutes.
[0031] Comparative Example 3 (cured using conventional UV curing)
[0032] To prepare an epoxy acrylate metallic coating, the following components were prepared by mass percentage: 50% epoxy acrylate resin, 20% trimethylolpropane triacrylate, 3% 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 10% zinc phosphate, 0.5% polyether-modified polydimethylsiloxane leveling agent, 0.5% polysiloxane defoamer, 2% alkyl ketene dimer, and 5% sodium alginate gel microspheres (particle size 10 μm). The remainder was deionized water as the solvent. The mixture was stirred at 800 rpm for 40 minutes at room temperature until homogeneous, and then allowed to stand to remove bubbles. For 20 minutes, degassing was performed using a vacuum degassing machine at a vacuum degree of -0.098 MPa to obtain the coating. The Q235 steel substrate underwent surface treatment, including sanding with 500-grit sandpaper, degreasing with acetone solvent, and drying at 70℃ for 15 minutes. The coating was then applied by spraying to a thickness of 50 μm. After coating, leveling was performed at room temperature for 3 minutes, followed by conventional UV curing. Gradient curing was not performed; instead, a UV-C light source with a wavelength of 255 nm and a light intensity of 250 mWh / cm² was used directly. 2 The exposure time is 30 seconds, with no pre-curing or post-curing steps.
[0033] Comparative Example 4 (Existing Technology Coatings)
[0034] To prepare an existing epoxy acrylate metallic coating, the following components were used by weight percentage: 50% epoxy acrylate resin, 20% trimethylolpropane triacrylate, 3% 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 10% zinc phosphate, 0.5% polyether-modified polydimethylsiloxane leveling agent, and 0.5% polysiloxane defoamer. The remainder was deionized water as solvent. No alkyl ketene dimers or sodium alginate gel microspheres were added. The mixture was stirred at 800 rpm for 40 minutes at room temperature until homogeneous, and then allowed to stand. The coating was degassed for 20 minutes using a vacuum degassed machine at a vacuum degree of -0.098 MPa to obtain the coating material. The Q235 steel substrate underwent surface treatment, including sanding with 500-grit sandpaper, degreasing with acetone solvent, and drying at 70℃ for 15 minutes. The coating was then applied by spraying to a thickness of 50 μm. After coating, it was leveled at room temperature for 3 minutes, and then cured using a conventional UV-C light source with a wavelength of 255 nm and a light intensity of 250 mWh / cm². 2 The exposure time is 30 seconds, with no pre-curing or post-curing steps.
[0035] The above embodiments and comparative examples were tested using the following methods, and the results are shown in Table 1.
[0036] Detection method:
[0037] Salt spray testing according to ASTM B117 standard: Prepare coating samples measuring 100mm × 150mm, place them in a salt spray chamber at 35℃, spray with 5% sodium chloride solution, check for blistering or corrosion every 24 hours, and record the number of hours until coating failure (obvious corrosion spots). Thermal cycling test: Place the sample in a -40℃ environment for 30 minutes, then transfer it to a 150℃ environment for 30 minutes, repeat 10 times, and observe the surface cracking rate (cracked area as a percentage of total area) under a microscope. Abrasion resistance testing according to ASTM D4060 standard: Use a Tiber abrasion tester with a 1kg load, CS-10 rotating wheel, and weigh the sample after 1000 rotations. Adhesion testing according to ASTM D3359 standard: Cross-cut test, 1mm spacing, rating from 1 (no peeling) to 5 (severe peeling).
[0038] Table 1 Test Results
[0039]
[0040]
[0041] Test data from Examples 1-3 and Comparative Examples 1-4 of this invention show that the coating performance is significantly improved through the synergistic effect of specific component compounding and gradient photocuring process. A comparison of Example 1 with Comparative Examples 1 and 2 demonstrates that the compounding of alkyl ketene dimer and sodium alginate microspheres is key to improving corrosion and crack resistance. AKD migrates to the coating surface during the pre-curing stage to form a dense hydrophobic layer, effectively blocking moisture penetration; sodium alginate microspheres absorb permeated moisture and slowly release zinc ions during the main curing stage, achieving long-term corrosion protection. Both are indispensable; a single component cannot simultaneously solve the problems of surface hydrophobicity and internal corrosion protection. Furthermore, the addition of alumina micropowder in Example 3 further improved wear resistance, indicating good compatibility between the functional filler and the core component. The thermal cycling cracking rate of Examples 1-3 after gradient photocuring was 0%, while the cracking rate of Comparative Example 3 reached 60%, and that of Comparative Example 4 reached 70%. The fundamental reason lies in the three-stage design of gradient photocuring: pre-curing initiates initial cross-linking of the coating, providing a time window for AKD migration; main curing completes deep cross-linking, but high-energy curing is controlled within a short time to avoid microcrack formation; post-curing eliminates internal stress through molecular chain relaxation. In contrast, the single UV curing in Comparative Example 3 resulted in an excessively rapid cross-linking rate, leaving insufficient time for molecular chain orientation and generating residual stress. In existing technologies, the functions of AKD as a papermaking hydrophobic agent or sodium alginate as a pharmaceutical sustained-release material have been disclosed, but neither has revealed a synergistic mechanism between AKD and gradient photocuring in coatings. This invention found that the migration rate of AKD under UV-A light is approximately three times higher than at room temperature, which is completely different from the thermal activation mechanism in papermaking applications; sodium alginate microspheres maintain structural integrity under UV-C irradiation, while conventional UV curing leads to their cracking and failure. These phenomena indicate that the specific wavelength and energy distribution of gradient photocuring produce unexpected interactions with cross-domain components. Data from Comparative Examples 1-4 further confirm that simply combining known components or processes cannot achieve the effects of this invention. This invention solves the problem of long-term protection of metal coatings in humid and hot environments by combining the above-mentioned components with the new process.
[0042] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
[0043] The present invention and its embodiments have been described above. This description is not restrictive, but merely one embodiment of the present invention, and the actual application is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar methods and embodiments without departing from the spirit of the present invention, they should all fall within the protection scope of the present invention.
Claims
1. A method for preparing an epoxy acrylate metal coating based on gradient photocuring, characterized in that, Includes the following steps: An epoxy acrylate metal coating is applied to a metal substrate with a coating thickness of 10μm-100μm, and then subjected to gradient light curing, which includes pre-curing, main curing and post-curing steps.
2. The method for preparing epoxy acrylate metal coating based on gradient photocuring according to claim 1, characterized in that, The pre-curing step uses a UV-A light source with a wavelength of 320nm-390nm and a light intensity of 50mWh / cm². 2 -100mWh / cm 2 The exposure time is 10s-30s.
3. The method for preparing epoxy acrylate metal coating based on gradient photocuring according to claim 1, characterized in that, The main curing step uses a UV-C light source with a wavelength of 250nm-260nm and a light intensity of 200mWh / cm². 2 -300mWh / cm 2 The exposure time is 5s-15s.
4. The method for preparing epoxy acrylate metal coating based on gradient photocuring according to claim 1, characterized in that, The post-curing step uses a visible light LED light source with a wavelength of 450nm and a light intensity of 80mWh / cm². 2 -120mWh / cm 2 Simultaneously heat to 80℃-100℃ for 10min-30min.
5. The method for preparing epoxy acrylate metal coating based on gradient photocuring according to claim 1, characterized in that, The metal substrate is one of steel, aluminum or copper, and surface treatment is required before coating, including sanding, degreasing and drying. Sanding is done with sandpaper with a grit of 400-600 mesh, degreasing is done with acetone or ethanol solvent, drying temperature is 60℃-80℃, and drying time is 10min-20min.
6. The method for preparing epoxy acrylate metal coating based on gradient photocuring according to claim 1, characterized in that, In the gradient photocuring step, UV-reversible color-changing spiropyran may also be added as a stress indicator, with an addition amount of 0.01%-0.1% of the total mass of the coating, and / or polydimethylsiloxane microemulsion may be added as a release agent, with an addition amount of 0.5%-2% of the total mass of the coating.
7. The method for preparing epoxy acrylate metal coating based on gradient photocuring according to claim 1, characterized in that, The coating method is one of spraying, brushing or roller coating. After coating, it needs to be leveled at room temperature for 1-5 minutes before gradient light curing.
8. The method for preparing epoxy acrylate metal coating based on gradient photocuring according to claim 1, characterized in that, The epoxy acrylate metal coating comprises the following components: epoxy acrylate resin, reactive diluent, photoinitiator, anti-corrosion pigment, additives, hydrophobic agent, and slow-release microspheres.
9. The method for preparing epoxy acrylate metal coating based on gradient photocuring according to claim 8, characterized in that, The hydrophobic agent is an alkyl ketene dimer, added at 0.5%-5% of the total coating mass; the slow-release microspheres are sodium alginate gel microspheres, added at 1%-10% of the total coating mass, and the particle size of the sodium alginate gel microspheres is 1μm-50μm; the epoxy acrylate resin is added at 30%-60% of the total coating mass; the reactive diluent is at least one of trimethylolpropane triacrylate or 1,6-hexanediol diacrylate, added at 10%-30% of the total coating mass. The photoinitiator is at least one of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide or phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and the addition amount is 1%-5% of the total mass of the coating. The anti-corrosion pigment is zinc phosphate, and the addition amount is 5%-20% of the total mass of the coating. The additives include leveling agents and defoamers. The leveling agent is polyether-modified polydimethylsiloxane, and the addition amount is 0.1%-1% of the total mass of the coating. The defoamer is polysiloxane emulsion, and the addition amount is 0.1%-1% of the total mass of the coating.
10. The method for preparing epoxy acrylate metal coating based on gradient photocuring according to claim 8 or 9, characterized in that, The preparation method of the epoxy acrylate metal coating includes the following steps: mixing epoxy acrylate resin, reactive diluent, photoinitiator, anti-corrosion pigment, additives, hydrophobic agent and slow-release microspheres at room temperature, and then stirring at 500 rpm-1000 rpm for 30 min-60 min until the mixture is uniform. The mixing step is carried out under light-protected conditions, and the mixture needs to be allowed to stand for degassing for 10-30 minutes. Degassing is performed using a vacuum degassing machine with a vacuum degree of -0.095MPa to 0.1MPa and a degassing time of 5-15 minutes.