High-strength outdoor van body water-based paint and preparation method thereof

Abstract

The application relates to the technical field of water-based paint, in particular to high-strength outdoor compartment water-based paint and a preparation method thereof. The high-strength outdoor compartment water-based paint is prepared from the following raw materials in parts by mass: 30-40 parts of water-based aliphatic polyurethane acrylate resin, 5-15 parts of water-based ultraviolet light curing polyurethane dispersion, 1-5 parts of carboxyl-modified polystyrene microspheres, 6-15 parts of dendritic silicon dioxide, 1-5 parts of a photoinitiator, 1-5 parts of polyethylene glycol diacrylate monomer, 1-5 parts of polydipentaerythritol hexaacrylate monomer, 1-5 parts of dipropylene glycol methyl ether, 1-5 parts of propylene glycol and 5-10 parts of auxiliary materials. The water-based UV curing system is adopted, the curing speed is high, the crosslinking degree is high, the weather resistance and the anti-yellowing ability of the coating can be effectively improved, the coating can maintain excellent appearance and performance stability in long-term outdoor use, and the preparation method is simple and suitable for large-scale popularization and application.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water-based paint, in particular to a high-strength outdoor compartment water-based paint and a preparation method thereof. BACKGROUND

[0002] Water-based UV paint has become a research hotspot in the paint industry because it combines the low VOC emission advantage of water-based paint and the rapid curing characteristics of UV light curing paint. However, the current market water-based paint for outdoor use generally has poor flexibility and impact resistance, insufficient wear resistance, and weak aging resistance, which leads to cracking, yellowing, blistering, loss of gloss, and peeling of the paint layer after long-term use, and it is difficult to meet the requirements of long-term weather resistance and mechanical properties of outdoor compartments.

[0003] Outdoor compartment coatings need to be exposed to sunlight, rain, acid rain, dust, and other harsh environments, and also experience cold and hot alternation and microbial erosion, so they must have excellent aging resistance. Although traditional water-based paint is more environmentally friendly, it has slow curing speed and low cross-linking density, which leads to insufficient aging resistance of the coating film. Traditional UV paint, although it has fast curing and high hardness, has large curing shrinkage and poor flexibility, and is difficult to adapt to thermal expansion and cold contraction in outdoor environments.

[0004] Water-based UV paint can significantly improve the cross-linking density and mechanical properties of the coating film while ensuring low VOC emission by introducing UV light curing technology, effectively solving the problems of slow curing and insufficient weather resistance of traditional water-based paint. However, existing water-based UV paint cannot simultaneously meet the comprehensive needs of high impact resistance and long-term weather resistance of outdoor compartments.

[0005] Therefore, it is of great significance to develop a water-based outdoor compartment coating with high flexibility, excellent wear resistance, and excellent aging resistance to improve the long-term performance of the coating film and reduce maintenance costs. SUMMARY

[0006] The present application relates to the technical field of water-based paint, in particular to a high-strength outdoor compartment water-based paint and a preparation method thereof.

[0007] A high-strength outdoor compartment water-based paint, the raw materials of which include, by mass fraction: water-based aliphatic polyurethane acrylate resin 30-40 parts, water-based UV curing polyurethane dispersion 5-15 parts, carboxyl-modified polystyrene microspheres 1-5 parts, dendritic silica 6-15 parts, photoinitiator 1-5 parts, polyethylene glycol diacrylate monomer 1-5 parts, polydiisopropyl alcohol 1-5 parts, propylene glycol 1-5 parts, and auxiliary materials 5-10 parts.

[0008] Preferably, the photoinitiator comprises 2,4,6 (trimethylbenzoyl) diphenyl phosphine oxide, 1-hydroxy-cyclohexyl-phenyl ketone, and the mass ratio of 2,4,6 (trimethylbenzoyl) diphenyl phosphine oxide, 1-hydroxy-cyclohexyl-phenyl ketone is 0.5-1.5:1.

[0009] Preferably, the adjuvant comprises a wetting agent, a defoaming agent, a leveling agent, a pH regulator, a thickening agent.

[0010] More preferably, the mass ratio of the wetting agent, the defoaming agent, the leveling agent, the pH regulator, the thickening agent is 1-2:1-2:1-2:1-2:1-2.

[0011] Preferably, the dendritic silica is prepared by the following steps: adding a dendritic polymer template into an ethanol aqueous solution and stirring for 10-30 min, adding an ammonia aqueous solution dropwise under stirring, continuing to stir for 5-15 min, adding tetraethyl orthosilicate dropwise under stirring, stirring for 5-10 h, standing for 10-15 h, adding a silane coupling agent and stirring for 1-2 h, centrifuging, washing, and vacuum drying.

[0012] More preferably, the mass fraction of the ammonia aqueous solution is 15-20%, and the mass ratio of the dendritic polymer template, the ammonia aqueous solution, the tetraethyl orthosilicate, and the silane coupling agent is 1-3:5-10:5-12:0.1-1.

[0013] More preferably, the dendritic polymer template is an amino-terminated polyamide-amine or a hyperbranched polylysine.

[0014] Preferably, the carboxyl-modified polystyrene microspheres are prepared by the following steps: adding polystyrene microspheres into an ethanol aqueous solution and stirring until uniform, adding azobisisobutyronitrile, α-methacrylic acid, and styrene under nitrogen protection, stirring at 60-80℃ for 5-15 h, filtering, washing, drying, and crushing.

[0015] More preferably, the mass ratio of the polystyrene microspheres, azobisisobutyronitrile, α-methacrylic acid, and styrene is 1-5:0.01-0.1:0.1-0.2:0.1-0.5.

[0016] The preparation method of the high-strength outdoor compartment water-based paint comprises the following steps:

[0017] S1, uniformly mixing the water-based aliphatic polyurethane acrylate resin and the water-based ultraviolet light curing polyurethane dispersion, adding the dendritic silica and the carboxyl-modified polystyrene microspheres and continuing to stir for 10-30 min to obtain a premix;

[0018] S2, the photoinitiator, polyethylene glycol diacrylate monomer, polydiisopropylidene amine monomer, dipropylene glycol methyl ether, propylene glycol, adjuvant are added into water and stirred for 10-30 min, the premix is added and stirred for 10-20 min, and then filtered.

[0019] Beneficial effects:

[0020] The present application adopts dendritic polymer (amino-terminated polyamide-amine or hyperbranched polylysine) as a template to guide the hydrolysis and deposition of tetraethyl orthosilicate to form silica particles with dendritic structure, and the surface is grafted and modified by silane coupling agent, which effectively inhibits particle agglomeration and improves the dispersion uniformity in the resin system.

[0021] The dendritic silica can form a multi-level dispersion network inside the coating due to its unique three-dimensional branched structure, enhancing the mechanical strength and impact resistance of the coating. The large specific surface area and high active sites of the dendritic silica enable it to chemically bond with active groups (such as isocyanate groups, carboxyl groups, etc.) in the resin, effectively filling the micropores and defects inside the coating and improving the compactness and surface hardness of the coating.

[0022] The introduction of carboxyl-modified polystyrene microspheres into the system has good elasticity and deformation recovery ability, which can effectively absorb external impact energy and prevent the coating from cracking or falling off when subjected to external force, thereby significantly improving the flexibility and impact resistance of the coating. At the same time, the uniformly distributed elastic support structure formed by the carboxyl-modified polystyrene microspheres in the coating can effectively disperse external friction and reduce the wear of the coating film surface. The synergistic effect of the two significantly improves the wear resistance of the coating and prolongs the service life of the coating film in long-term use.

[0023] The present application constructs a stable and dense coating structure through the synergistic effect of high crosslinking density resin system and functional fillers, effectively blocking the erosion of external environment (such as ultraviolet light, acid rain, oxygen, moisture, etc.) on the coating, and uses dendritic silica and carboxyl-modified polystyrene microspheres to make the coating have good thermal stability and environmental adaptability, which can effectively alleviate the deformation and aging of the coating in cold and hot alternating, high humidity and other environments.

[0024] The present application adopts water-based UV curing system, which has fast curing speed and high crosslinking degree, can effectively improve the weather resistance and anti-yellowing ability of the coating, and make the coating maintain excellent appearance and performance stability in long-term outdoor use. The preparation method is simple and suitable for large-scale popularization and application. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 Comparison chart of impact resistance and wear resistance of the coating prepared by using the high-strength outdoor compartment water-based paint obtained in Example 5 and Comparative Examples 1-2. DETAILED DESCRIPTION

[0026] The application will be further described in connection with specific examples.

[0027] The waterborne aliphatic polyurethane acrylate resin used below is from Zhenxin Resin, with the trade name of UCECOAT 7230. The waterborne UV-curable polyurethane dispersion used below is from Covestro, with the trade name of Bayhydrol® UV 2282. The polyethylene glycol diacrylate monomer used below is purchased from Guangdong Taixin Material Co., Ltd., and is specifically PEG200DA (a low-molecular-weight bifunctional monomer in the PEG200DA series). The polydi-pentaerythritol hexaacrylate monomer used below is a bifunctional polydi-pentaerythritol hexaacrylate, purchased from Guangzhou Shilibo Technology Co., Ltd. ® 7230. The waterborne UV-curable polyurethane dispersion used below is from Covestro, with the trade name of Bayhydrol® UV 2282. The polyethylene glycol diacrylate monomer used below is purchased from Guangdong Taixin Material Co., Ltd., and is specifically PEG200DA (a low-molecular-weight bifunctional monomer in the PEG200DA series). The polydi-pentaerythritol hexaacrylate monomer used below is a bifunctional polydi-pentaerythritol hexaacrylate, purchased from Guangzhou Shilibo Technology Co., Ltd.

[0028] The auxiliary used below is composed of a wetting agent, a defoaming agent, a leveling agent, a pH regulator, and a thickening agent, with a mass ratio of 1:1:1:1:1; and the wetting agent, the defoaming agent, the leveling agent, the pH regulator, and the thickening agent are all from BYK, Germany, such as BYK-190 for the wetting agent and BYK-028 for the defoaming agent.

[0029] Example 1

[0030] A high-strength outdoor van waterborne paint, whose raw materials include: 300 g of a waterborne aliphatic polyurethane acrylate resin, 50 g of a waterborne UV-curable polyurethane dispersion, 10 g of carboxyl-modified polystyrene microspheres, 60 g of dendritic silica, 10 g of a photoinitiator, 10 g of a polyethylene glycol diacrylate monomer, 10 g of a polydi-pentaerythritol hexaacrylate monomer, 10 g of dipropylene glycol methyl ether, 10 g of propylene glycol, and 50 g of an auxiliary.

[0031] The photoinitiator is composed of 2,4,6-trimethylbenzoyl diphenyl phosphine oxide and 1-hydroxy-cyclohexyl-phenyl ketone, with a mass ratio of 0.5:1.

[0032] The dendritic silica is prepared by the following steps: 10 g of hyperbranched polylysine is added to 500 g of an ethanol aqueous solution with a mass fraction of 50%, stirred at a speed of 1000 r / min for 10 min, 50 g of an ammonia aqueous solution with a mass fraction of 15% is added dropwise in a stirring state, stirring is continued for 5 min, 50 g of tetraethyl orthosilicate is added dropwise in a stirring state, stirring is continued for 5 h, the solution is left to stand for 10 h, 1 g of silane coupling agent KH-550 is added, stirring is continued at a speed of 100 r / min for 1 h, centrifugation is performed, and the product is washed with ethanol and deionized water alternately, and vacuum dried.

[0033] The carboxyl-modified polystyrene microspheres are prepared by the following steps: 10 g of polystyrene microspheres with a particle size of 200-500 nm are added into 200 g of 60% ethanol aqueous solution and stirred uniformly, 0.1 g of azobisisobutyronitrile, 1 g of alpha-methyl acrylic acid and 1 g of styrene are added into the solution under nitrogen protection, stirring at 60 ℃ for 5 h, filtering, washing, drying and crushing.

[0034] The preparation method of the high-strength outdoor compartment water-based paint comprises the following steps:

[0035] S1, uniformly mix the water-based aliphatic polyurethane acrylate resin and the water-based ultraviolet curing polyurethane dispersion, add dendritic silica and carboxyl-modified polystyrene microspheres and continue to stir for 10 min at a stirring speed of 100 r / min to obtain a premix;

[0036] S2, add the photoinitiator, polyethylene glycol diacrylate monomer, polydiisopropylidene polyol hexaacrylate monomer, dipropylene glycol methyl ether, propylene glycol and auxiliary materials into 100 g of water, stir at a speed of 1000 r / min for 10 min, add the premix and continue to stir for 10 min, and filter.

[0037] Example 2

[0038] A high-strength outdoor compartment water-based paint, raw materials of which include: 400 g of water-based aliphatic polyurethane acrylate resin, 150 g of water-based ultraviolet curing polyurethane dispersion, 50 g of carboxyl-modified polystyrene microspheres, 150 g of dendritic silica, 50 g of photoinitiator, 50 g of polyethylene glycol diacrylate monomer, 50 g of polydiisopropylidene polyol hexaacrylate monomer, 50 g of dipropylene glycol methyl ether, 50 g of propylene glycol and 100 g of auxiliary materials.

[0039] The photoinitiator is composed of 2,4,6 (trimethylbenzoyl) diphenyl phosphine oxide and 1-hydroxy-cyclohexyl-phenyl ketone at a mass ratio of 1.5:1.

[0040] The dendritic silica is prepared by the following steps: 30 g of amino-terminated polyamide-amine (G2.0) is added into 600 g of 60% ethanol aqueous solution and stirred at a speed of 1500 r / min for 30 min, 100 g of 20% ammonia water solution is added dropwise into the solution under stirring, and the stirring is continued for 15 min, 120 g of tetraethyl orthosilicate is added dropwise into the solution under stirring, and the stirring is continued for 10 h, the solution is left to stand for 15 h, 10 g of silane coupling agent KH-550 is added, and the stirring is continued for 2 h at a speed of 300 r / min, and then the solution is centrifuged, washed with ethanol and deionized water alternately, and vacuum dried.

[0041] The carboxyl-modified polystyrene microspheres are prepared by the following steps: 50 g of polystyrene microspheres with a particle size of 200-500 nm are added into 400 g of 70% ethanol aqueous solution, and stirred uniformly, 1 g of azobisisobutyronitrile, 2 g of α-methyl acrylic acid, and 5 g of styrene are added into the solution under nitrogen protection, and stirred at 80 ℃ for 15 h, filtered, washed, dried, and crushed.

[0042] The preparation method of the high-strength outdoor compartment water-based paint comprises the following steps:

[0043] S1, the water-based aliphatic polyurethane acrylate resin, the water-based ultraviolet curing polyurethane dispersion is mixed uniformly, the dendritic silica, the carboxyl-modified polystyrene microspheres continue to stir 30 min, the stirring speed is 400 r / min, the premix is obtained;

[0044] S2, the photoinitiator, the polyethylene glycol diacrylate monomer, the polydiisopropylidene polyol hexaacrylate monomer, the dipropylene glycol methyl ether, the propylene glycol, and the auxiliary are added into 300 g of water, stirred at a speed of 1500 r / min for 30 min, the premix is added and stirred for 20 min, and filtered.

[0045] Example 3

[0046] A high-strength outdoor compartment water-based paint, the raw materials of which comprise: 330 g of water-based aliphatic polyurethane acrylate resin, 120 g of water-based ultraviolet curing polyurethane dispersion, 20 g of carboxyl-modified polystyrene microspheres, 120 g of dendritic silica, 20 g of photoinitiator, 40 g of polyethylene glycol diacrylate monomer, 20 g of polydiisopropylidene polyol hexaacrylate monomer, 40 g of dipropylene glycol methyl ether, 20 g of propylene glycol, and 80 g of auxiliary.

[0047] The photoinitiator is composed of 2,4,6 (trimethylbenzoyl) diphenyl phosphine oxide and 1-hydroxy-cyclohexyl-phenyl ketone at a mass ratio of 0.8:1.

[0048] The dendritic silica is prepared by the following steps: 25 g of amino-terminated polyamide-amine (G3.0) is added into 520 g of 57% ethanol aqueous solution, stirred at a speed of 1100 r / min for 25 min, 70 g of 18% ammonia solution is added dropwise into the solution under stirring, and stirred for another 8 min, 100 g of tetraethyl orthosilicate is added dropwise into the solution under stirring, stirred for 7 h, and placed for 13 h, 3 g of silane coupling agent KH-550 is added, stirred at a speed of 250 r / min for 80 min, centrifuged, washed with ethanol and deionized water alternately, and vacuum dried.

[0049] The carboxyl-modified polystyrene microspheres are prepared by the following steps: 40 g of polystyrene microspheres with a particle size of 200-500 nm are added into 250 g of an ethanol aqueous solution with a mass fraction of 68%, and stirred uniformly, 0.3 g of azobisisobutyronitrile, 1.8 g of α-methyl acrylic acid, and 2 g of styrene are added into the solution under nitrogen protection, and stirred at a temperature of 75 ℃ for 8 h, filtered, washed, dried, and crushed.

[0050] The preparation method of the high-strength outdoor compartment water-based paint comprises the following steps:

[0051] S1, uniformly mix the water-based aliphatic polyurethane acrylate resin and the water-based ultraviolet light curing polyurethane dispersion, continue to stir the dendritic silicon dioxide and the carboxyl-modified polystyrene microspheres for 25 min at a stirring speed of 200 r / min, to obtain a premix;

[0052] S2, add the photoinitiator, the polyethylene glycol diacrylate monomer, the polydi-pentaerythritol hexaacrylate monomer, the dipropylene glycol methyl ether, the propylene glycol, and the auxiliary into 250 g of water, stir at a speed of 1100 r / min for 25 min, add the premix and continue to stir for 12 min, and filter.

[0053] Example 4

[0054] The high-strength outdoor compartment water-based paint comprises the following raw materials: 370 g of water-based aliphatic polyurethane acrylate resin, 80 g of water-based ultraviolet light curing polyurethane dispersion, 40 g of carboxyl-modified polystyrene microspheres, 80 g of dendritic silicon dioxide, 40 g of photoinitiator, 20 g of polyethylene glycol diacrylate monomer, 40 g of polydi-pentaerythritol hexaacrylate monomer, 20 g of dipropylene glycol methyl ether, 40 g of propylene glycol, and 70 g of auxiliary.

[0055] The photoinitiator is composed of 2,4,6 (trimethylbenzoyl) diphenyl phosphine oxide and 1-hydroxy-cyclohexyl-phenyl ketone at a mass ratio of 1.2:1.

[0056] The dendritic silicon dioxide is prepared by the following steps: 15 g of amino-terminated polyamide-amine (G2.5) is added into 580 g of an ethanol aqueous solution with a mass fraction of 53%, stirred at a speed of 1300 r / min for 15 min, 90 g of an ammonia solution with a mass fraction of 16% is added dropwise into the solution under stirring, continue to stir for 12 min, 60 g of tetraethyl orthosilicate is added dropwise into the solution under stirring, stir for 9 h, stand for 11 h, 7 g of silane coupling agent KH-550 is added, stir at a speed of 150 r / min for 100 min, centrifuge, wash with ethanol and deionized water alternately, and vacuum dry.

[0057] The carboxyl-modified polystyrene microspheres are prepared by the following steps: 20 g of polystyrene microspheres with a particle size of 200-500 nm are added into 350 g of an ethanol aqueous solution with a mass fraction of 62%, and stirred uniformly, 0.7 g of azobisisobutyronitrile, 1.2 g of α-methyl acrylic acid, and 4 g of styrene are added into the solution under nitrogen protection, and stirred at a temperature of 65 ℃ for 12 h, and then filtered, washed, dried, and crushed.

[0058] The preparation method of the high-strength outdoor compartment water-based paint comprises the following steps:

[0059] S1, uniformly mix the water-based aliphatic polyurethane acrylate resin and the water-based ultraviolet light curing polyurethane dispersion, continue to stir the dendritic silicon dioxide and the carboxyl-modified polystyrene microspheres for 15 min at a stirring speed of 300 r / min, and obtain a premix;

[0060] S2, add the photoinitiator, the polyethylene glycol diacrylate monomer, the polydi-pentaerythritol hexaacrylate monomer, the dipropylene glycol methyl ether, the propylene glycol, and the auxiliary into 150 g of water, stir at a speed of 1300 r / min for 15 min, continue to stir the premix for 18 min, and then filter.

[0061] Example 5

[0062] The high-strength outdoor compartment water-based paint comprises the following raw materials: 350 g of water-based aliphatic polyurethane acrylate resin, 100 g of water-based ultraviolet light curing polyurethane dispersion, 30 g of carboxyl-modified polystyrene microspheres, 100 g of dendritic silicon dioxide, 30 g of photoinitiator, 30 g of polyethylene glycol diacrylate monomer, 30 g of polydi-pentaerythritol hexaacrylate monomer, 30 g of dipropylene glycol methyl ether, 30 g of propylene glycol, and 75 g of auxiliary.

[0063] The photoinitiator is composed of 2,4,6 (trimethylbenzoyl) diphenyl phosphine oxide and 1-hydroxy-cyclohexyl-phenyl ketone at a mass ratio of 1:1.

[0064] The dendritic silicon dioxide is prepared by the following steps: 20 g of amino-terminated polyamide-amine (G2.5) is added into 550 g of an ethanol aqueous solution with a mass fraction of 55%, and stirred at a speed of 1200 r / min for 20 min, 80 g of an ammonia solution with a mass fraction of 17% is added dropwise into the solution under stirring, and continue to stir for 10 min, 80 g of tetraethyl orthosilicate is added dropwise into the solution under stirring, and stirred for 8 h, and then placed for 12 h, 5 g of silane coupling agent KH-550 is added, and stirred at a speed of 200 r / min for 90 min, centrifuged, washed with ethanol and deionized water alternately, and vacuum dried.

[0065] The carboxyl-modified polystyrene microspheres are prepared by the following steps: 30 g of polystyrene microspheres with a particle size of 200-500 nm are added into 300 g of an ethanol aqueous solution with a mass fraction of 65%, and stirred uniformly, 0.5 g of azobisisobutyronitrile, 1.5 g of α-methyl acrylic acid, and 3 g of styrene are added into the solution under nitrogen protection, and stirred at a temperature of 70 ℃ for 10 h, and then filtered, washed, dried, and crushed.

[0066] The preparation method of the high-strength outdoor compartment water-based paint comprises the following steps:

[0067] S1, the water-based aliphatic polyurethane acrylate resin, the water-based ultraviolet curing polyurethane dispersion is mixed uniformly, the dendritic silica, the carboxyl-modified polystyrene microspheres continue to stir 20 min, the stirring speed is 250 r / min, the premix is obtained;

[0068] S2, the photoinitiator, the polyethylene glycol diacrylate monomer, the polydiisopropylidene polyol hexaacrylate monomer, the dipropylene glycol methyl ether, the propylene glycol, and the auxiliary are added into 200 g of water, stirred at a speed of 1200 r / min for 20 min, the premix is added and stirred for 15 min, and then filtered.

[0069] Comparative Example 1

[0070] A high-strength outdoor compartment water-based paint, raw materials of which include: 350 g of water-based aliphatic polyurethane acrylate resin, 100 g of water-based ultraviolet curing polyurethane dispersion, 30 g of carboxyl-modified polystyrene microspheres, 100 g of dendritic silica, 30 g of photoinitiator, 30 g of polyethylene glycol diacrylate monomer, 30 g of polydiisopropylidene polyol hexaacrylate monomer, 30 g of dipropylene glycol methyl ether, 30 g of propylene glycol, and 75 g of auxiliary.

[0071] The photoinitiator is composed of 2,4,6 (trimethylbenzoyl) diphenyl phosphine oxide and 1-hydroxy-cyclohexyl-phenyl ketone at a mass ratio of 1:1.

[0072] The dendritic silica is prepared by the following steps: 80 g of ammonia solution with a mass fraction of 17% is added dropwise into 550 g of an ethanol aqueous solution with a mass fraction of 55%, and stirred for 10 min, 80 g of tetraethyl orthosilicate is added dropwise into the solution under stirring, stirred for 8 h, and then placed for 12 h, 5 g of silane coupling agent KH-550 is added, stirred at a speed of 200 r / min for 90 min, centrifuged, washed with ethanol and deionized water alternately, vacuum dried, and 20 g of amino-terminated polyamide-amine (G2.5) is added and mixed uniformly.

[0073] The carboxyl-modified polystyrene microspheres are prepared by the following steps: 30 g of polystyrene microspheres with a particle size of 200-500 nm are added into 300 g of an ethanol aqueous solution with a mass fraction of 65%, and stirred uniformly, 0.5 g of azobisisobutyronitrile, 1.5 g of α-methyl acrylic acid, and 3 g of styrene are added into the solution under nitrogen protection, and stirred at a temperature of 70 ℃ for 10 h, and then filtered, washed, dried, and crushed.

[0074] The preparation method of the high-strength outdoor compartment water-based paint comprises the following steps:

[0075] S1, uniformly mix the water-based aliphatic polyurethane acrylate resin and the water-based ultraviolet light-cured polyurethane dispersion, continue to stir the dendritic silicon dioxide and the carboxyl-modified polystyrene microspheres for 20 min at a stirring speed of 250 r / min, and obtain a premix;

[0076] S2, add the photoinitiator, the polyethylene glycol diacrylate monomer, the polydi-pentaerythritol hexaacrylate monomer, the dipropylene glycol methyl ether, the propylene glycol, and the auxiliary into 200 g of water, stir at a speed of 1200 r / min for 20 min, continue to stir the premix for 15 min, and then filter.

[0077] Comparative Example 2

[0078] The high-strength outdoor compartment water-based paint comprises the following raw materials: 350 g of water-based aliphatic polyurethane acrylate resin, 100 g of water-based ultraviolet light-cured polyurethane dispersion, 30 g of polystyrene microspheres, 100 g of dendritic silicon dioxide, 30 g of photoinitiator, 30 g of polyethylene glycol diacrylate monomer, 30 g of polydi-pentaerythritol hexaacrylate monomer, 30 g of dipropylene glycol methyl ether, 30 g of propylene glycol, and 75 g of auxiliary.

[0079] The photoinitiator is composed of 2,4,6 (trimethylbenzoyl) diphenyl phosphine oxide and 1-hydroxy-cyclohexyl-phenyl ketone at a mass ratio of 1:1.

[0080] The dendritic silicon dioxide is prepared by the following steps: 20 g of amino-terminated polyamide-amine (G2.5) is added into 550 g of an ethanol aqueous solution with a mass fraction of 55%, and stirred at a speed of 1200 r / min for 20 min, 80 g of an ammonia solution with a mass fraction of 17% is added dropwise into the solution under stirring, and continue to stir for 10 min, 80 g of tetraethyl orthosilicate is added dropwise into the solution under stirring, and stirred for 8 h, and then placed for 12 h, 5 g of silane coupling agent KH-550 is added, and stirred at a speed of 200 r / min for 90 min, centrifuged, washed with ethanol and deionized water alternately, and vacuum dried.

[0081] The preparation method of the high-strength outdoor compartment water-based paint comprises the following steps:

[0082] S1. Mix the waterborne aliphatic polyurethane acrylate resin and waterborne UV-curable polyurethane dispersion evenly, add dendritic silica and polystyrene microspheres and continue stirring for 20 minutes at a stirring speed of 250 r / min to obtain the premix.

[0083] S2. Add the photoinitiator, polyethylene glycol diacrylate monomer, polydipentaerythritol hexaacrylate monomer, dipropylene glycol methyl ether, propylene glycol, and excipients to 200g of water, stir at 1200r / min for 20min, add the premix and continue stirring for 15min, then filter.

[0084] The high-strength outdoor water-based paints obtained in Example 5 and Comparative Examples 1-2 were applied to the surface of tinplate sheets, dried at 50°C for 30 minutes, and then cured under a high-pressure ultraviolet mercury lamp (spectral energy distribution centered at 365 nm, transmission rate of 15 m / min). The coating thickness of each group was 50 ± 5 μm.

[0085] The hardness of the above-mentioned coating samples was determined according to GB / T 6739-2022 "Determination of Hardness of Paints and Varnishes by Pencil Method". The adhesion of the above-mentioned coating samples was evaluated according to GB / T 9286-2021 "Cross-cut Test of Paints and Varnishes". The flexibility of the above-mentioned coating samples was determined according to GB / T 1731-2020 "Determination of Flexibility of Paint Films and Putty Films". The results are shown in Table 1.

[0086] Table 1 shows the results of hardness, adhesion, and flexibility of the coatings obtained in Example 5 and Comparative Examples 1-2.

[0087] Example 5 Comparative Example 1 Comparative Example 2 Pencil hardness H B HB Crosshatch test 0 1 1 Flexibility 1 mm 2 mm 4 mm

[0088] As can be seen from Table 1, the coating prepared using Example 5 has the best hardness, adhesion and flexibility, which is better than Comparative Examples 1-2.

[0089] The impact resistance of the above-mentioned coating samples was tested according to GB / T 1732-2020 "Determination of Impact Resistance of Paint Films" (since 50 kg·cm was insufficient to meet the testing requirements, an additional weight was used for further testing). The abrasion resistance (1000 g × 500 r) of the above-mentioned coating samples was tested according to GB / T1768-2006 "Determination of Abrasion Resistance of Paints and Varnishes - Rotating Rubber Grinding Wheel Method".

[0090] The results are as follows Figure 1 As shown, the coating prepared using Example 5 has the highest impact resistance and the lowest abrasion resistance, which is better than Comparative Examples 1-2 (P<0.05).

[0091] The coating samples of each group were subjected to ultraviolet exposure for 52 weeks according to GB / T 14522-2008 "Artificial Climate Aging Test Method for Plastic, Coating and Rubber Materials for Mechanical Industry Products - Fluorescent Ultraviolet Lamp", and the blistering and cracking grades of the coating samples of each group after ultraviolet exposure were determined according to GB / T 33568-2017 "Aging Grade and Evaluation Method for Wood Coating Surface for Outdoor Use". The results are shown in Table 2.

[0092] Table 2: Aging resistance results of the coatings obtained from Example 5 and Comparative Examples 1-2.

[0093] Example 5 Comparative Example 1 Comparative Example 2 Number of blisters 0 2 2 Blisters size S0 S2 S2 Number of cracks 0 1 2 Cracks size S0 S2 S2

[0094] It can be seen from Table 2 that the coating prepared by using Example 5 has the best aging resistance, which is better than Comparative Examples 1-2.

[0095] The coating samples of each group were subjected to cold and hot cycle treatment according to CNCIA-HG / T 0004-2012 "Cold and Hot Cycle Test Method for Color Paint and Varnish Film", and the blistering and cracking grades of the coating samples of each group after cold and hot cycle were determined according to GB / T 33568-2017 "Aging Grade and Evaluation Method for Wood Coating Surface for Outdoor Use". The results are shown in Table 3.

[0096] Table 3: Cold and hot cycle results of the coatings obtained from Example 5 and Comparative Examples 1-2.

[0097] Example 5 Comparative Example 1 Comparative Example 2 Number of blisters 0 1 2 Blisters size S0 S1 S2 Number of cracks 0 1 2 Cracks size S0 S2 S2

[0098] It can be seen from Table 3 that the coating prepared by using Example 5 has the best cold and hot cycle performance, which is better than Comparative Examples 1-2.

[0099] The reason for the above results is that the present application adopts dendritic polymers (amino-terminated polyamide-amine or hyperbranched polylysine) as templates to guide the hydrolysis and deposition of tetraethyl orthosilicate to form silica particles with dendritic structure, and to perform surface graft modification through silane coupling agent, effectively inhibiting particle agglomeration and improving its dispersion uniformity in the resin system. Dendritic silica can form a multi-level dispersion network inside the coating due to its unique three-dimensional branched structure, enhancing the mechanical strength and impact resistance of the coating. The large specific surface area and high active sites of dendritic silica enable it to chemically bond with active groups (such as isocyanate groups, carboxyl groups, etc.) in the resin, effectively filling the micropores and defects inside the coating and improving the compactness and surface hardness of the coating. The carboxyl-modified polystyrene microspheres introduced into the system have good elasticity and deformation recovery ability, which can effectively absorb external impact energy and prevent the coating from cracking or falling off when subjected to external force, thereby significantly improving the flexibility and impact resistance of the coating. At the same time, the carboxyl-modified polystyrene microspheres form a uniformly distributed elastic support structure in the coating, which can effectively disperse external friction and reduce the wear of the coating film surface. And by compounding dendritic silica with carboxyl-modified polystyrene microspheres, the coating has good thermal stability and environmental adaptability, which can effectively alleviate the deformation and aging of the coating under alternating cold and hot, high humidity and other environments, and significantly improve the wear resistance of the coating, prolonging the service life of the coating film in long-term use.

[0100] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can make equivalent replacement or change according to the technical solution and inventive concept of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A high strength outdoor box body water-based paint, characterized by, The raw materials thereof include, by mass fraction: water-based aliphatic polyurethane acrylate resin 30-40 parts, water-based ultraviolet curing polyurethane dispersion 5-15 parts, carboxyl modified polystyrene microspheres 1-5 parts, dendritic silica 6-15 parts, photoinitiator 1-5 parts, polyethylene glycol diacrylate monomer 1-5 parts, polydiisopropylidene glycol hexaacrylate monomer 1-5 parts, dipropylene glycol methyl ether 1-5 parts, propylene glycol 1-5 parts, auxiliary materials 5-10 parts; The dendritic silica is prepared by the following steps: dendritic polymer template is added to an ethanol aqueous solution and stirred for 10-30 min, ammonia solution is added dropwise thereto under stirring, stirring is continued for 5-15 min, tetraethyl orthosilicate is added dropwise thereto under stirring, stirring is continued for 5-10 h, it is left to stand for 10-15 h, silane coupling agent is added and stirred for 1-2 h, it is centrifuged, washed, and vacuum dried; The dendritic polymer template is amino-terminated polyamidoamine or hyperbranched polylysine.

2. The high strength outdoor box body water-based paint according to claim 1, characterized in that, The photoinitiator includes: 2,4,6 (trimethylbenzoyl) diphenyl phosphine oxide, 1-hydroxy-cyclohexyl-phenyl ketone, and the mass ratio of 2,4,6 (trimethylbenzoyl) diphenyl phosphine oxide, 1-hydroxy-cyclohexyl-phenyl ketone is 0.5-1.5:

1.

3. The high strength outdoor box body water-based paint according to claim 1, characterized in that, The auxiliary materials include: wetting agent, defoaming agent, leveling agent, pH adjuster, thickening agent.

4. The high strength outdoor box body water-based paint according to claim 3, characterized by, The mass ratio of wetting agent, defoaming agent, leveling agent, pH adjuster, thickening agent is 1-2:1-2:1-2:1-2:1-2.

5. The high strength outdoor box body water-based paint according to claim 1, characterized in that, The mass fraction of ammonia solution is 15-20%, and the mass ratio of dendritic polymer template, ammonia solution, tetraethyl orthosilicate, silane coupling agent is 1-3:5-10:5-12:0.1-1.

6. The high strength outdoor box body water-based paint according to claim 1, characterized by, The carboxyl modified polystyrene microspheres are prepared by the following steps: polystyrene microspheres are added to an ethanol aqueous solution and stirred uniformly, azobisisobutyronitrile, alpha-methacrylic acid, and styrene are added thereto under nitrogen protection, stirring is continued at 60-80℃ for 5-15 h, it is filtered, washed, and dried, and it is crushed.

7. The high strength outdoor box body water-based paint according to claim 6, characterized by, The mass ratio of polystyrene microspheres, azobisisobutyronitrile, alpha-methacrylic acid, and styrene is 1-5:0.01-0.1:0.1-0.2:0.1-0.

5.

8. A process for the preparation of a high strength outdoor box body waterborne paint according to any one of claims 1 to 7, characterized in that, Including the following steps: S1, the water-based aliphatic polyurethane acrylate resin, water-based ultraviolet curing polyurethane dispersion is mixed uniformly, dendritic silica, carboxyl modified polystyrene microspheres are added and continue to stir for 10-30 min, to obtain a premix; S2, the photoinitiator, polyethylene glycol diacrylate monomer, polydiisopropylidene glycol hexaacrylate monomer, dipropylene glycol methyl ether, propylene glycol, auxiliary materials are added to water and stirred for 10-30 min, the premix is added and continue to stir for 10-20 min, and it is filtered.

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