A luminescent nano zinc oxide modified white pigment and its preparation and application in colored thick coating photocuring coatings

Abstract

This invention belongs to the technical field of coatings, and discloses a luminescent nano-zinc oxide modified white pigment, its preparation, and its application in colored thick-coat photocurable coatings. The preparation method of the luminescent nano-zinc oxide modified white pigment involves reacting a silane coupling agent with the pigment in an organic solvent at 40-70°C for 3-5 hours; subsequently, nano-zinc oxide is added, and the reaction is carried out at 60-90°C for 5-7 hours to obtain the modified pigment; the pigment is one or more of silica and titanium dioxide. This invention solves the problem of insufficient photocuring depth caused by the scattering, refraction, and absorption of light by pigments in colored coatings. By using the luminescent nano-zinc oxide modified white pigment in the preparation of colored thick-coat photocurable coatings, this invention can guide the light source of the nano-zinc oxide to a deeper layer, achieving deep curing. The method of this invention is simple, efficient, and widely applicable, and can effectively improve the depth of photocurable coatings.

Description

Technical Field

[0001] The invention belongs to the technical field of coatings, and in particular relates to a luminous nano zinc oxide particle modified white pigment and its preparation and application in a photocurable colored thick coating. Background Art

[0002] Colored photocuring systems are widely used in 3D printing, dental materials, coatings and other fields. However, the pigments in the UV curing system have strong absorption of light, which greatly reduces the penetration of light and leads to incomplete curing in deep areas. A method of changing the wavelength of the light source has been proposed to increase the depth of photocuring. Chinese patent application CN113895031A discloses a green light photocuring material, which uses different photoinitiators and has a maximum curing depth of 62mm, which can be used for rapid model manufacturing. Chinese patent application CN112408993A discloses a mixed light source curing method, which combines a variety of photoinitiators with different absorption peaks to achieve full absorption of 245-405nm wavelengths, thereby ensuring a curing depth of more than 100μm. Chinese patent CN110698607B discloses a polymerization method for a black system with an added upconversion material. The upconversion material converts infrared light into ultraviolet light and visible light, thereby reducing the absorption of the light source by dark pigments. These methods replace ultraviolet light with more penetrating visible light and infrared light. Although this increases the depth of photocuring, it requires a longer curing time and the development of more efficient photoinitiators.

[0003] It is also a common method to modify the pigment to reduce the absorption of the light source. Chinese patent application CN113458389A discloses a method for modifying aluminum alloy powder. The dispersion of the powder is improved by coating with polystyrene, thereby increasing the depth of photocuring. Chinese patent application CN113548899A discloses a method for preparing a modified silicon nitride ceramic slurry. First, the silicon nitride powder is oxidized at high temperature to reduce its absorbance, and then the surface is modified with a silane coupling agent to enhance its dispersion. The two effects work together to greatly increase the curing depth. These surface modification methods are not universal, and different modification methods need to be selected according to different pigment types, which are complicated to operate.

[0004] The current methods for increasing the curing depth all have certain defects and cannot give full play to the advantages of UV curing. Summary of the invention

[0005] In view of the shortcomings and deficiencies of the above prior art, the purpose of the present invention is to provide a luminescent nano zinc oxide modified white pigment and a preparation method thereof. The zinc oxide nanoparticles of the present invention can be used as ultraviolet light initiators and have the characteristics of photoluminescence, and the light source can be introduced into the interior of the curing system to achieve deep curing. The present invention uses a silane coupling agent to modify the luminescent nano zinc oxide, links the nano zinc oxide to titanium dioxide particles or white carbon black particles, and produces a multifunctional inorganic composite pigment with three functions of luminescence, photoinitiation and coloring.

[0006] Another object of the present invention is to provide the application of the above-mentioned nano zinc oxide luminescent particles modified white pigment. The nano zinc oxide luminescent particles modified white pigment is used to prepare colored thick coating photocurable coatings. In the coating, the nano zinc oxide of the present invention is used first as an endogenous luminescent material, second as a modified pigment, and third as a photoinitiator, which is added to the coating to prepare a photocurable colored thick coating coating. The present invention chemically reacts the luminescent / photoinitiating dual-functional nano zinc oxide onto the particle surface of titanium dioxide / white carbon black through a silane coupling agent, and can color and photocure a very thick coating film.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A method for preparing a luminescent nano zinc oxide particle modified white pigment comprises the following steps:

[0009] 1) In an organic solvent, react the silane coupling agent and the pigment at 40-70°C for 3-5h; then add nano zinc oxide and react at 60-90°C for 5-7h to obtain a modified pigment;

[0010] The pigment is one or more of white carbon black and titanium dioxide; the molar ratio of the pigment to the silane coupling agent is 1:(1-5); the molar ratio of the pigment to nano zinc oxide is 1:(1-5).

[0011] The organic solvent is one or more of toluene, xylene, ethyl acetate, butyl acetate and cyclohexanone.

[0012] The silane coupling agent is at least one of 3-aminopropyltriethoxysilane (KH550), 3-(2,3-epoxypropyl)propyltrimethoxysilane (KH560), and 3-(methacryloyloxy)propyltrimethoxysilane (KH570).

[0013] After the reaction, centrifuge, wash and dry.

[0014] The centrifugal condition is a rotation speed of 8000-10000 r / min for 5-10 min; the washing is anhydrous ethanol washing; and the drying refers to drying at 55-65° C. for 12-24 h.

[0015] The nano zinc oxide is prepared by the following method:

[0016] Add the ethanol solution of sodium hydroxide dropwise into the ethanol solution of zinc acetate dihydrate, and stir to react at 0-5°C.

[0017] The concentration of the zinc acetate dihydrate ethanol solution is 0.001-0.1M;

[0018] The molar ratio of zinc acetate dihydrate to sodium hydroxide is 1:(1-3);

[0019] The stirring speed is 1000-2200 r / min; the dropping speed of the sodium hydroxide ethanol solution is 15-80 drops / min.

[0020] In the preparation of nano zinc oxide, centrifugation, washing and drying are performed after the reaction. In the preparation of nano zinc oxide, the centrifugation condition is 8000-12000r / min for 15-30min; the washing is washing with anhydrous ethanol; the drying condition is drying at 35-60°C for 12-30h. The drying is vacuum drying.

[0021] The mass volume ratio of sodium hydroxide to ethanol in the sodium hydroxide ethanol solution is (0.1-0.5) g:50 mL.

[0022] After the sodium hydroxide ethanol solution is dripped, continue the reaction for 20 to 60 minutes.

[0023] The sodium hydroxide ethanol solution is prepared by ultrasonically dispersing the sodium hydroxide in anhydrous ethanol, and the dispersion time is 20 to 40 minutes.

[0024] The ethanol solution of zinc acetate dihydrate is prepared by ultrasonically dispersing zinc acetate dihydrate in anhydrous ethanol, and the dispersion time is 20 to 40 minutes.

[0025] A method for preparing a photocurable colored thick coating (the thickness of the coating is 50-100 microns) comprises the following steps:

[0026] S1: In an organic solvent, the nano zinc oxide and the luminescent nano zinc oxide modified white pigment (i.e., modified pigment) are mixed evenly, or the modified pigment is dispersed in an organic solvent; then a photoinitiator and an active diluent are added and dispersed evenly, and polyurethane acrylate is added and mixed evenly to obtain a light-curing coating;

[0027] S2: coating the light-curing coating, placing, drying, and light-curing to obtain a light-cured film;

[0028] The active diluent is at least one of 1,6-hexanediol diacrylate (HDDA), tripropylene glycol diacrylate (TPGDA), and trimethylolpropane triacrylate (TMPTA).

[0029] The organic solvent is ethanol;

[0030] The dosage of the nano zinc oxide is 0.2% to 1% of the total mass of the organic solvent and the active diluent, and the dosage of the pigment is 0.2% to 1% of the total mass of the organic solvent and the active diluent.

[0031] The photoinitiator is at least one of phenylbis(2,4,6-trimethylphenylacyl)phosphine oxide (819), 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO), and photoinitiator 4265, and the amount used is 0.02% to 0.1% of the total mass of the organic solvent and the active diluent.

[0032] The amount of the active diluent is 10% to 30% of the total mass of the light-curing coating.

[0033] The amount of the polyurethane acrylate used is 70% to 90% of the total mass of the light-curing coating.

[0034] The polyurethane acrylate is at least one of monofunctional polyurethane acrylate (containing one double bond in each molecule), difunctional polyurethane acrylate (containing two double bonds in each molecule), trifunctional polyurethane acrylate (containing three double bonds in each molecule), and tetrafunctional polyurethane acrylate (containing four double bonds in each molecule).

[0035] The conditions of the light curing are as follows: the light source is a mercury lamp, 0.5-2kw, and the irradiation time is 30-200s; the placement time is 30-40 minutes, the drying temperature is 55-65°C, and the drying time is 1-2 hours.

[0036] The mass ratio of the organic solvent to the active diluent is 1:4.

[0037] The principle of the present invention is to use the photoluminescence effect of nano zinc oxide to introduce the light source into the deep layer. Zinc oxide is placed on the surface of the pigment through a silane coupling agent, and the light irradiated on the surface of the pigment is introduced into the deep layer through the photoluminescence effect of zinc oxide, thereby reducing the absorption of the light source by the pigment.

[0038] The preparation method of the present invention and the obtained product have the following advantages and beneficial effects:

[0039] (1) The thick coating preparation method of the present invention has the advantages of simple operation and wide application range.

[0040] (2) The present invention increases the light curing depth and improves the paint film performance by changing the addition amount of nano zinc oxide.

[0041] (3) The modified pigment provided by the present invention has reduced light absorption and can transmit light into the deep layer through the nano zinc oxide on the surface, thereby obtaining a deeper curing depth. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 These are electron microscope images of the pigment before and after modification in Example 1, (a): SiO2 (white carbon black): before modification, (b): SiO2: KH550: ZnO = 1:1:1: after modification, i.e. nano zinc oxide modified white carbon black particles. DETAILED DESCRIPTION

[0043] The present invention is further described in detail below in conjunction with the embodiments, but the implementation method of the present invention is not limited thereto.

[0044] The main sources of raw materials involved in the following examples are as follows:

[0045] The zinc acetate dihydrate is from Tianjin Damao Chemical Reagent Factory, analytical grade; the sodium hydroxide is from Guangzhou Chemical Reagent Factory, analytical grade; the 1,6-hexanediol diacrylate (HDDA), tripropylene glycol diacrylate (TPGDA), trimethylolpropane triacrylate (TMPTA), monofunctional polyurethane acrylate, difunctional polyurethane acrylate, trifunctional polyurethane acrylate, and tetrafunctional polyurethane acrylate are from Changxing Chemical Materials Co., Ltd., industrial grade; the phenyl bis(2,4,6-trimethylphenylacyl)phosphine oxide (819) is from BASF, industrial grade; the anhydrous ethanol is from Chengdu Cologne Chemical Co., Ltd., analytical grade; the toluene is from Chengdu Cologne Chemical Co., Ltd., analytical grade; the white carbon black (SiO2) and titanium dioxide are from Tianjin Komio Chemical Reagent Co., Ltd., analytical grade; the 3-aminopropyltriethoxysilane (KH550) is from Nanjing Silicon Union Chemical Co., Ltd., industrial grade.

[0046] Example 1

[0047] (1) Add 1.1g Zn(CH3COO)2.2H2O to 50ml ethanol and ultrasonically disperse for 30min, then transfer to a four-necked flask. Add 0.4g NaOH to 50ml ethanol and ultrasonically disperse for 30min, then drip into the four-necked flask at a rate of 40 drops / min, and react at a stirring speed of 2200r / min and 0°C. Continue to react for 30min after the dripping. After the reaction is completed, centrifuge the product at a speed of 12000r / min for 15min, use anhydrous ethanol as a detergent, and centrifuge and wash three times. Finally, dry at 60°C for 24h to obtain nano zinc oxide.

[0048] (2) 0.02 g of 3-aminopropyltriethoxysilane and 0.02 g of white carbon black were added to 1 g of toluene, and the mixture was reacted at 40 °C for 5 h. Then, 0.02 g of nano zinc oxide was added, and the mixture was reacted at 60 °C for 7 h. The mixture was then centrifuged at 8000 r / min for 10 min. Anhydrous ethanol was added as a detergent, and the centrifugation and washing were repeated three times. Finally, the mixture was dried at 60 °C for 24 h to obtain nano zinc oxide-modified white carbon black particles.

[0049] (3) Add 0.05 g of nano zinc oxide modified white carbon black particles to 1 g of anhydrous ethanol, and ultrasonically disperse for 10 minutes. Then add 0.005 g of photoinitiator 819, 0.5 g of 1,6-hexanediol diacrylate and 5 g of polyurethane acrylate, and ultrasonically disperse for 20 minutes. Then, apply a coating with a thickness of 80 μm, leave it at room temperature for 30 minutes, dry it in a drying oven at 60°C for 1 hour, and then cure it under a 1 kW mercury lamp for 45 seconds to obtain a light-cured paint film.

[0050] Figure 1 These are electron microscope images of the pigment before and after modification in Example 1, (a): SiO2 (white carbon black): before modification, (b): SiO2: KH550: ZnO = 1:1:1: after modification, i.e. nano zinc oxide modified white carbon black particles.

[0051] Example 2

[0052] (1) Add 1.1g Zn(CH3COO)2.2H2O to 50ml ethanol and ultrasonically disperse for 30min, then transfer to a four-necked flask. Add 0.4g NaOH to 50ml ethanol and ultrasonically disperse for 30min, then drip into the four-necked flask at a rate of 40 drops / min, and react at a stirring speed of 2200r / min and 0°C. Continue to react for 30min after the addition is completed. After the reaction is completed, the product is centrifuged at a speed of 12000r / min for 15min, and anhydrous ethanol is used as a detergent, and then centrifuged and washed three times. Finally, it is dried at 60°C for 24h to obtain nano zinc oxide.

[0053] (2) Add 0.015 g of 3-(2,3-epoxypropyl)propyltrimethoxysilane and 0.015 g of white carbon black to 1 g of toluene, react at 55°C for 4 h, then add 0.015 g of nano zinc oxide, react at 75°C for 6 h, then centrifuge at 9000 r / min for 8 min, add anhydrous ethanol as a detergent, repeat centrifugation and washing three times, and finally dry at 60°C for 24 h to obtain nano zinc oxide modified white carbon black particles.

[0054] (3) Add 0.06 g of nano zinc oxide modified white carbon black particles to 1 g of anhydrous ethanol and disperse them by ultrasonication for 10 minutes. Then add 0.006 g of photoinitiator 819, 0.5 g of tripropylene glycol diacrylate and 5 g of polyurethane acrylate and disperse them by ultrasonication for 20 minutes. Then, apply the coating to a thickness of 120 μm, place it at room temperature for 30 minutes, dry it in a drying oven at 60°C for 1 hour, and then cure it under a 1 kW mercury lamp for 45 seconds to obtain a photocured paint film.

[0055] Example 3

[0056] (1) Add 1.1g Zn(CH3COO)2.2H2O to 50ml ethanol and ultrasonically disperse for 30min, then transfer to a four-necked flask. Add 0.4g NaOH to 50ml ethanol and ultrasonically disperse for 30min, then drip into the four-necked flask at a rate of 40 drops / min, and react at a stirring speed of 2200r / min and 0°C. Continue to react for 30min after the addition is completed. After the reaction is completed, the product is centrifuged at a speed of 12000r / min for 15min, and anhydrous ethanol is used as a detergent, and then centrifuged and washed three times. Finally, it is dried at 60°C for 24h to obtain nano zinc oxide.

[0057] (2) 0.05 g of 3-(methacryloyloxy)propyltrimethoxysilane and 0.05 g of white carbon black were added to 1 g of toluene, and the mixture was reacted at 70°C for 3 h. Then, 0.05 g of nano zinc oxide was added, and the mixture was reacted at 90°C for 5 h. The mixture was then centrifuged at 10,000 r / min for 6 min, and anhydrous ethanol was added as a detergent. The centrifugation and washing were repeated three times. Finally, the mixture was dried at 60°C for 24 h to obtain nano zinc oxide-modified white carbon black particles.

[0058] (3) Add 0.04 g of nano zinc oxide modified white carbon black particles to 1 g of anhydrous ethanol and disperse them by ultrasonication for 10 minutes. Then add 0.004 g of photoinitiator 819, 0.5 g of trimethylolpropane triacrylate and 5 g of polyurethane acrylate and disperse them by ultrasonication for 20 minutes. Then, apply the coating to a thickness of 100 μm, leave it at room temperature for 30 minutes, dry it in a drying oven at 60°C for 1 hour, and then cure it under a 1 kW mercury lamp for 45 seconds to obtain a photocured paint film.

[0059] Example 4

[0060] (1) Add 1.1g Zn(CH3COO)2.2H2O to 50ml ethanol and ultrasonically disperse for 30min, then transfer to a four-necked flask. Add 0.4g NaOH to 50ml ethanol and ultrasonically disperse for 30min, then drip into the four-necked flask at a rate of 40 drops / min, and react at a stirring speed of 2200r / min and 0°C. Continue to react for 30min. After the reaction is completed, centrifuge the product at a speed of 12000r / min for 15min, use anhydrous ethanol as a detergent, and centrifuge and wash three times. Finally, dry at 60°C for 24h to obtain nano zinc oxide.

[0061] (2) Add 0.02 g of 3-aminopropyltriethoxysilane and 0.02 g of titanium dioxide to 1 g of toluene, react at 40°C for 5 h, then add 0.02 g of nano zinc oxide, react at 60°C for 7 h, then centrifuge at 8000 r / min for 10 min, add anhydrous ethanol as a detergent, repeat centrifugation and washing three times, and finally dry at 60°C for 24 h to obtain nano zinc oxide modified titanium dioxide particles.

[0062] (3) Add 0.05 g of nano zinc oxide modified titanium dioxide particles to 1 g of anhydrous ethanol and disperse them by ultrasonication for 10 minutes. Then add 0.005 g of photoinitiator 819, 0.5 g of 1,6-hexanediol diacrylate and 5 g of polyurethane acrylate and disperse them by ultrasonication for 20 minutes. Then, apply the coating to a thickness of 80 μm, place it at room temperature for 30 minutes, dry it in a drying oven at 60°C for 1 hour, and then cure it under a 1 kW mercury lamp for 45 seconds to obtain a photocured paint film.

[0063] Example 5

[0064] (1) Add 1.1g Zn(CH3COO)2.2H2O to 50ml ethanol and ultrasonically disperse for 30min, then transfer to a four-necked flask. Add 0.4g NaOH to 50ml ethanol and ultrasonically disperse for 30min, then drip into the four-necked flask at a rate of 40 drops / min, and react at a stirring speed of 2200r / min and 0°C. Continue to react for 30min after the addition is completed. After the reaction is completed, the product is centrifuged at a speed of 12000r / min for 15min, and anhydrous ethanol is used as a detergent, and then centrifuged and washed three times. Finally, it is dried at 60°C for 24h to obtain nano zinc oxide.

[0065] (2) Add 0.015 g of 3-(2,3-epoxypropyl)propyltrimethoxysilane and 0.015 g of titanium dioxide to 1 g of toluene, react at 55°C for 4 h, then add 0.015 g of nano zinc oxide, react at 75°C for 6 h, then centrifuge at 9000 r / min for 8 min, add anhydrous ethanol as a detergent, repeat centrifugation and washing three times, and finally dry at 60°C for 24 h to obtain nano zinc oxide modified titanium dioxide particles.

[0066] (3) Add 0.06 g of nano zinc oxide modified titanium dioxide particles to 1 g of anhydrous ethanol and disperse them ultrasonically for 10 minutes. Then add 0.006 g of photoinitiator 819, 0.5 g of tripropylene glycol diacrylate and 5 g of polyurethane acrylate and disperse them ultrasonically for 20 minutes. Then, apply the coating to a thickness of 120 μm, leave it at room temperature for 30 minutes, dry it in a drying oven at 60°C for 1 hour, and then cure it under a 1 kW mercury lamp for 45 seconds to obtain a photocured paint film.

[0067] Example 6

[0068] (1) Add 1.1g Zn(CH3COO)2.2H2O to 50ml ethanol and ultrasonically disperse for 30min, then transfer to a four-necked flask. Add 0.4g NaOH to 50ml ethanol and ultrasonically disperse for 30min, then drip into the four-necked flask at a rate of 40 drops / min, and react at a stirring speed of 2200r / min and 0°C. Continue to react for 30min after the addition is completed. After the reaction is completed, the product is centrifuged at a speed of 12000r / min for 15min, and anhydrous ethanol is used as a detergent, and then centrifuged and washed three times. Finally, it is dried at 60°C for 24h to obtain nano zinc oxide.

[0069] (2) Add 0.05 g of 3-(methacryloyloxy)propyltrimethoxysilane and 0.05 g of titanium dioxide to 1 g of toluene, react at 70°C for 3 h, then add 0.05 g of nano zinc oxide, react at 90°C for 5 h, then centrifuge at 10,000 r / min for 6 min, add anhydrous ethanol as a detergent, repeat centrifugation and washing three times, and finally dry at 60°C for 24 h to obtain nano zinc oxide modified titanium dioxide particles.

[0070] (3) Add 0.04 g of nano zinc oxide modified titanium dioxide particles to 1 g of anhydrous ethanol and disperse them by ultrasonication for 10 minutes. Then add 0.004 g of photoinitiator 819, 0.5 g of trimethylolpropane triacrylate and 5 g of polyurethane acrylate and disperse them by ultrasonication for 20 minutes. Then, apply the coating to a thickness of 100 μm, leave it at room temperature for 30 minutes, dry it in a drying oven at 60°C for 1 hour, and then cure it under a 1 kW mercury lamp for 45 seconds to obtain a photocured paint film.

[0071] Comparative Example 1

[0072] (1) Add 1.1g Zn(CH3COO)2.2H2O to 50ml ethanol and ultrasonically disperse for 30min, then transfer to a four-necked flask. Add 0.4g NaOH to 50ml ethanol and ultrasonically disperse for 30min, then drip into the four-necked flask at a rate of 40 drops / min, and react at a stirring speed of 2200r / min and 0°C. Continue to react for 30min after the addition is completed. After the reaction is completed, the product is centrifuged at a speed of 12000r / min for 15min, and anhydrous ethanol is used as a detergent, and then centrifuged and washed three times. Finally, it is dried at 60°C for 24h to obtain nano zinc oxide.

[0073] (2) Add 0.025 g of nano zinc oxide and 0.025 g of white carbon black to 1 g of anhydrous ethanol, and ultrasonically disperse for 10 minutes. Then add 0.005 g of photoinitiator 819, 0.5 g of 1,6-hexanediol diacrylate and 5 g of polyurethane acrylate, and ultrasonically disperse for 20 minutes. Then, apply a coating with a thickness of 30 μm, leave it at room temperature for 30 minutes, dry it in a drying oven at 60°C for 1 hour, and then cure it under a 1 kW mercury lamp for 45 seconds to obtain a light-cured paint film.

[0074] Comparative Example 2

[0075] (1) Add 1.1g Zn(CH3COO)2.2H2O to 50ml ethanol and ultrasonically disperse for 30min, then transfer to a four-necked flask. Add 0.4g NaOH to 50ml ethanol and ultrasonically disperse for 30min, then drip into the four-necked flask at a rate of 40 drops / min, and react at a stirring speed of 2200r / min and 0°C. Continue to react for 30min after the addition is completed. After the reaction is completed, the product is centrifuged at a speed of 12000r / min for 15min, and anhydrous ethanol is used as a detergent, and then centrifuged and washed three times. Finally, it is dried at 60°C for 24h to obtain nano zinc oxide.

[0076] (2) Add 0.025 g of nano zinc oxide and 0.025 g of titanium dioxide to 1 g of anhydrous ethanol, and ultrasonically disperse for 10 minutes. Then add 0.005 g of photoinitiator 819, 0.5 g of 1,6-hexanediol diacrylate and 5 g of polyurethane acrylate, and ultrasonically disperse for 20 minutes. Then, apply a coating with a thickness of 30 μm, leave it at room temperature for 30 minutes, dry it in a drying oven at 60°C for 1 hour, and then cure it under a 1 kW mercury lamp for 45 seconds to obtain a photocured paint film.

[0077] Table 1 Paint film properties of comparative examples 1-2 and examples 1-6

[0078]

[0079] From the results in Table 1, it can be seen that the chemical modification of nano zinc oxide with white carbon black and titanium dioxide can increase the pencil hardness and improve the water resistance and alcohol resistance.

[0080] To test the depth of cure, an example is as follows:

[0081] Example 7

[0082] (1) Add 1.1g Zn(CH3COO)2.2H2O to 50ml ethanol and ultrasonically disperse for 30min, then transfer to a four-necked flask. Add 0.4g NaOH to 50ml ethanol and ultrasonically disperse for 30min, then drip into the four-necked flask at a rate of 40 drops / min, and react at a stirring speed of 2200r / min and 0°C. Continue to react for 30min after the addition is completed. After the reaction is completed, the product is centrifuged at a speed of 12000r / min for 15min and washed three times with anhydrous ethanol. Finally, dry at 60°C for 24h to obtain nano zinc oxide powder.

[0083] (2) Add 0.02 g of nano zinc oxide powder and 0.01 g of white carbon black powder to 1 g of anhydrous ethanol and stir for 1 h. Then add 0.0030 g of photoinitiator 819 and 4 g of HDDA and disperse by ultrasound for 30 min. Inject the obtained mixture into a plastic tube and cure it under a light source for 120 s.

[0084] Example 8

[0085] (1) Add 0.25g of white carbon black powder to 50g of toluene and ultrasonically disperse it for 30min, then transfer it to a 250ml four-necked flask. Add 2.046g of KH550 to 5g of anhydrous ethanol, mix well and add it to a four-necked flask. The reaction was stirred at 65°C for 3h. Then, 0.556g of nano zinc oxide (nano zinc oxide prepared in Example 1) was added to 30g of anhydrous toluene and ultrasonically dispersed for 30min, then added to a four-necked flask and reacted at 85°C for 5h. After the reaction, the mixture was centrifuged at 8000rpm for 5min, washed with anhydrous ethanol 3 times, and the solid was dried in a vacuum drying oven at 60°C for 24h to obtain a modified white carbon black sample.

[0086] (2) Add 0.02 g of nano zinc oxide powder (nano zinc oxide prepared in Example 1) and 0.01 g of modified white carbon black powder to 1 g of ethanol and stir for 1 h. Then add 0.0030 g of photoinitiator 819 and 4 g of HDDA and disperse by ultrasound for 30 min. Inject the obtained mixture into a plastic tube and cure it under a light source for 120 s.

[0087] Table 2 Curing depth of Example 7 and Example 8

[0088]

[0089] The results in Table 2 show that modified pigments can increase the curing depth, and the curing depth of Example 8 is the largest, which is 14 mm.

Claims

1. A method for preparing a colored thick coating photocurable coating, characterized in that: The following steps are involved: S1: In an organic solvent, nano zinc oxide and luminescent nano zinc oxide modified white pigment are mixed, or the luminescent nano zinc oxide modified white pigment is dispersed in an organic solvent; then a photoinitiator and an active diluent are added and dispersed evenly, and then polyurethane acrylate is added and mixed to obtain a light-curing coating; S2: applying the light-curing coating, placing, drying, and light-curing to obtain a light-cured film; The active diluent is at least one of 1,6-hexanediol diacrylate, tripropylene glycol diacrylate, and trimethylolpropane triacrylate; The preparation method of the luminescent nano zinc oxide modified white pigment comprises the following steps: 1) In an organic solvent, a silane coupling agent and a pigment are reacted at 40-70° C. for 3-5 hours; then nano zinc oxide is added and reacted at 60-90° C. for 5-7 hours to obtain a modified pigment; the organic solvent is toluene and anhydrous ethanol; the pigment is one or more of white carbon black and titanium dioxide; the molar ratio of the pigment to the silane coupling agent is 1: (1-5); the molar ratio of the pigment to the nano zinc oxide is 1: (1-5); The thickness of the coating is 50-100 microns.

2. The method for preparing the colored thick coating photocurable paint according to claim 1, characterized in that: The silane coupling agent is at least one of 3-aminopropyltriethoxysilane, 3-(2,3-epoxypropyl)propyltrimethoxysilane and 3-(methacryloyloxy)propyltrimethoxysilane; The nano zinc oxide is prepared by the following method: dripping an ethanol solution of sodium hydroxide into an ethanol solution of zinc acetate dihydrate, and stirring the mixture at 0-5°C for reaction.

3. The method for preparing the colored thick coating photocurable paint according to claim 2, characterized in that: In the preparation of nano zinc oxide, The concentration of the zinc acetate dihydrate ethanol solution is 0.001~0.1 M; The molar ratio of zinc acetate dihydrate to sodium hydroxide is 1:(1-3); The stirring speed is 1000-2200 r / min, and the dropping speed is 15-80 drops / min; In the preparation of nano zinc oxide, after the reaction is completed, centrifugation, washing and drying are performed.

4. The method for preparing the colored thick coating photocurable paint according to claim 3, characterized in that: In the preparation of nano zinc oxide, the centrifugal condition is a rotation speed of 8000-12000 r / min for 15-30 min; the washing is washing with anhydrous ethanol; and the drying condition is drying at 35-65°C for 12-30 h.

5. The method for preparing the colored thick coating photocurable paint according to claim 1, characterized in that: In the preparation of the luminescent nano zinc oxide modified white pigment, after adding nano zinc oxide, reacting at 60-90 °C for 5-7 h, centrifuging, washing, and drying; The centrifugal condition is a rotation speed of 8000-10000 r / min for 5-10 min; the washing solvent is anhydrous ethanol; and the drying refers to drying at 55-65° C. for 12-24 h.

6. The method for preparing the colored thick coating photocurable paint according to claim 1, characterized in that: In the preparation of colored thick coating light-curing coatings, The organic solvent is ethanol; The amount of the nano zinc oxide is 0.2% to 1% of the total mass of the organic solvent and the active diluent, and the amount of the pigment is 0.2% to 1% of the total mass of the organic solvent and the active diluent; The photoinitiator is at least one of phenyl bis (2,4,6-trimethylphenyl acyl) phosphine oxide, 2,4,6-trimethylbenzoyl diphenyl phosphine oxide, and photoinitiator 4265, and the amount used is 0.02% to 0.1% of the total mass of the organic solvent and the active diluent; The amount of the active diluent is 10% to 30% of the total mass of the photocurable coating; The amount of the polyurethane acrylate used is 70% to 90% of the total mass of the photocurable coating.

7. The method for preparing the colored thick coating photocurable paint according to claim 1, characterized in that: The conditions for the light curing are as follows: the light source is a mercury lamp with a power of 0.5-2kW and an irradiation time of 30-200 s; the placement time is 30-40 minutes, the drying temperature is 55-65° C., and the drying time is 1-2 hours.

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