Aluminum pigment applied to UV coating and preparation method of aluminum pigment

Abstract

The invention discloses an aluminum pigment applied to a UV coating. The aluminum pigment is prepared from the following raw materials in parts by weight: 20-30 parts of a pigment main body, 40-75 parts of a reaction system solvent, 0.01-0.2 part of a polymerization inhibitor, 0.2-0.5 part of an acid treatment agent, 1.5-4.0 parts of an active passivator and 0.3-1.0 part of a dispersing agent. The invention also provides a preparation method of the aluminum pigment. An active passivator is adopted to treat the surface of the aluminum pigment, so that the aluminum pigment can participate in the overall polymerization reaction of the paint in the UV curing process, the paint film performance is improved, meanwhile, a proper active diluent is selected as a main solvent, dipropylene glycol diacrylate is introduced on the basis of retaining the flexibility of n-butyl acrylate and the compatibility of the aluminum pigment, and the paint film performance is improved. The cross-linking density and the curing rate are improved through the synergistic effect of functional groups, so that the aluminum pigment can directly participate in the curing process of the UV coating without pre-baking, VOC emission in the construction process is reduced, the construction energy consumption is reduced, the construction time is shortened, and meanwhile the metal texture and corrosion resistance of the aluminum pigment are not affected.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical materials, and more specifically, to an aluminum pigment applied to UV coatings and a preparation method thereof. Background Art

[0002] UV coatings are a type of ultraviolet light-curing coatings that can rapidly cure into a film under the irradiation of ultraviolet light. In recent years, UV coatings have developed rapidly and are widely used in various coating industries due to their low VOC emissions, fast curing speed, high film performance, high stability, and low energy consumption. However, since their main components are acrylic acid, acrylate monomers, and their prepolymers, they often have a relatively high acid value. In this case, it is required that the aluminum pigment has high acid stability and good system compatibility to maintain the long-term stability of the resin system before curing. At the same time, due to the difference in application scenarios, the cured film needs to have strong corrosion resistance. For aluminum pigments, this high corrosion resistance requirement often comes with the thickening of the coating layer, which also means sacrificing the hue of the aluminum pigment. At the same time, since almost all commercially available paste aluminum pigments contain a relatively high proportion of solvents that cannot participate in curing, during construction, it is necessary to divide it into two steps: pre-baking and curing, which will generate a certain amount of VOC emissions and greatly increase the construction energy consumption and time, which also limits the application of aluminum pigments in UV coatings to a certain extent.

[0003] Most commercially available passivated aluminum pigments are water-based aluminum pigments, which mainly use alcohols and ethers as the main solvents, and a small part uses water as the solvent. When these aluminum pigments are applied to UV coatings, they cannot directly cure into a film. Usually, it is necessary to pre-bake to remove the solvent first and then perform UV lamp curing. This process increases the VOC emissions during the construction process, and also increases the construction energy consumption and prolongs the construction time. Moreover, since UV coatings contain many reactive monomers, oligomers, etc., local self-polymerization is very likely to occur during the baking process, resulting in the affected film uniformity and further affecting the film performance. Secondly, due to the lack of active structures on the surface of conventional passivated and silica-type aluminum pigments participating in the UV curing reaction and simply binding by means of anchoring of polar groups, this will greatly reduce the affinity and corrosion resistance of the aluminum pigment, and at the same time, it cannot fully display the excellent film performance of UV coatings. Although resin-coated aluminum pigments have good resin binding performance and corrosion resistance, they cannot show good brightness. In view of this, we propose an aluminum pigment applied to UV coatings and a preparation method thereof. Summary of the Invention

[0004] Aiming at the deficiencies of the existing technologies, one of the objectives of the present invention is to provide an aluminum pigment applied to UV coatings, so as to solve the technical problems that most existing water-based aluminum pigments cannot be directly cured into a film when applied to UV coatings, resulting in an increase in VOC emissions and energy consumption during the construction process, and that conventional passivated and silica-based aluminum pigments have poor film performance because their surface has no active structure participating in the UV curing reaction.

[0005] To solve the above technical problems, the present invention provides the following technical solutions:

[0006] An aluminum pigment applied to UV coatings, which is composed of the following raw materials in parts by weight: 20-30 parts of a pigment main body, 40-75 parts of a reaction system solvent, 0.01-0.2 part of an inhibitor, 0.2-0.5 part of an acid treatment agent, 1.5-4.0 parts of an active passivator, and 0.3-1.0 part of a dispersant; wherein, the pigment main body is an oily flaky ball-milled aluminum pigment; the reaction system solvent includes an acrylate-based active diluent, a methacrylate-based active diluent, a vinyl-based active diluent or a vinyl polyether-based active diluent; the acrylate-based active diluent is a compound system of n-butyl acrylate (BA) and dipropylene glycol diacrylate (DPGDA); in the compound system, the proportion of n-butyl acrylate is 80-85%, and the proportion of dipropylene glycol diacrylate is 15-20%.

[0007] The present invention uses an active passivator to treat the surface of the aluminum pigment, so that it can participate in the overall polymerization reaction of the coating during the UV curing process, so as to completely integrate with the coating and improve the film performance. At the same time, by selecting a suitable active diluent to replace solvents such as alcohols, ethers and water as the main solvent of the water-based aluminum pigment, while retaining the flexibility of n-butyl acrylate and the compatibility with the aluminum pigment, dipropylene glycol diacrylate is introduced. Through the functional group synergistic effect, the crosslinking density and curing rate are improved, so that it can directly participate in the curing process of the UV coating without pre-baking, reducing the VOC emissions during the construction process, reducing the construction energy consumption, reducing the construction time, and at the same time not affecting the metallic texture and corrosion resistance of the aluminum pigment.

[0008] Preferably, the solid content of the oily flaky ball-milled aluminum pigment is controlled at 70-80% to reduce the proportion of the solvent. The solvent is one or several of D50, D70, 100#, 150#, the particle size D50 is 11-18 microns, and the particle size span is 0.8-1.0.

[0009] Preferably, the inhibitor is hydroquinone monomethyl ether. The addition of the inhibitor is to prevent the polymerization reaction of the active diluent as the solvent during the passivation process.

[0010] Preferably, the acid treatment agent is acrylic acid. Since the surface activity of the oily flaky aluminum pigment is relatively low, it needs to be acidified before the reaction to increase the active sites on its surface to assist the reaction. Therefore, an acidic active substance is selected for pretreatment.

[0011] Preferably, the active passivator is one or more of methacryloyloxyethyl phosphate, 2-hydroxyethyl methacrylate phosphate, ethylene glycol methacrylate phosphate, methacryloyloxyethyl succinic acid monoester, and methacryloyloxyethyl maleic acid monoester.

[0012] Preferably, the dispersant is propylene glycol.

[0013] The second object of the present invention is to provide a method for preparing the above-mentioned aluminum pigment applied to UV coatings, including the following steps:

[0014] (1) According to the weight ratio, put the pigment main body into a stainless steel stirring reaction kettle, and then put in the pigment main body. Set the temperature of the reaction kettle to 45°C, start stirring and heating. After the heating is completed, add the acid treatment agent thereto, and keep it warm and stir for a period of time to increase the active sites on the surface of the aluminum pigment;

[0015] (2) After the acid treatment is completed, take a part of the pre-prepared active passivator and add it to the reaction kettle, keep it warm and stir for 30 min, and then add the remaining part of the active passivator to the reaction kettle, and keep it warm and stir for a period of time to fully passivate the aluminum flakes with phosphate esters;

[0016] (3) After the stirring is completed, start cooling. When the cooling temperature is lower than 30°C, use a peristaltic pump to pump the reaction slurry into a filter press for pressure filtration. Then place the filter cake obtained by pressure filtration in an industrial kneading and stirring machine, add the dispersant and adjust the solid content to 25 - 40% with the reaction system solvent to obtain the finished product.

[0017] Further, in step (1), the maximum temperature of the heating is 50°C. The heating temperature should not be higher than 50°C, and the purpose is to prevent the inhibitor from failing and causing the self-polymerization of butyl acrylate.

[0018] Further, in step (1), the holding and stirring time is 3 - 6 h, and the stirring rate is 500 - 800 rpm. The holding and stirring time should not be less than 3 h, and the purpose is to ensure sufficient acid treatment.

[0019] Further, in step (2), the holding and stirring time is 6 - 8 h, and the stirring rate is 500 - 800 rpm. The total holding and stirring time should not be less than 6 h, and the purpose is to ensure that the aluminum flakes are fully passivated with phosphate esters.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] 1. The present invention treats the surface of aluminum pigments with an active passivator, enabling them to participate in the overall polymerization reaction of the coating during the UV curing process, so as to completely integrate with the coating and improve the film properties. At the same time, by selecting a suitable active diluent to replace solvents such as alcohols, ethers, and water as the main solvent for waterborne aluminum pigments, based on retaining the flexibility of n-butyl acrylate and the compatibility with aluminum pigments, dipropylene glycol diacrylate is introduced. Through the synergistic effect of functional groups, the crosslinking density and curing rate are increased, enabling it to directly participate in the UV coating curing process without pre-baking. While reducing the VOC emissions during construction, lowering the construction energy consumption, and reducing the construction time, it does not affect the metallic texture and corrosion resistance of aluminum pigments.

[0022] 2. The present invention treats aluminum pigments by means of phosphate passivation. The prepared product has a very low solvent content and can be directly cured into a film without pre-baking, greatly reducing the VOC emissions during construction, lowering the construction energy consumption, and reducing the construction time; and it has more excellent metallic texture and acid and alkali resistance compared with conventional waterborne silica-coated and resin-coated aluminum pigments, and the film properties are excellent.

[0023] 3. Since the active diluent serves as the solvent for the reaction system and does not participate in the passivation process of aluminum pigments itself, it can be selected and changed according to different UV resin systems, with a higher matching degree. And due to controlling a lower solid content, it does not need to be diluted again in actual application, and almost all of the active diluent used can be utilized. Description of the Drawings

[0024] Figure 1 It is a test result diagram of soaking each product in a 5% mass fraction NaOH aqueous solution in the embodiments of the present invention. In the figure, from left to right are commercially available passivated aluminum silver paste, commercially available silica-coated aluminum silver paste, commercially available resin-coated aluminum silver paste, and the aluminum pigment product prepared by the present invention;

[0025] Figure 2 It is a test result diagram of soaking each product in a 5% mass fraction HCl aqueous solution in the embodiments of the present invention. In the figure, from left to right are commercially available passivated aluminum silver paste, commercially available silica-coated aluminum silver paste, commercially available resin-coated aluminum silver paste, and the aluminum pigment product prepared by the present invention;

[0026] Figure 3 It is a comparison diagram of the whiteness of the UV system blade scraping test of the commercially available silica-coated aluminum silver paste and the aluminum pigment product prepared by the present invention in the embodiments of the present invention. In the figure, the left area is coated with the commercially available silica-coated aluminum silver paste, and the right area is coated with the aluminum pigment product prepared by the present invention;

[0027] Figure 4This is a comparison chart of the whiteness of commercially available passivated aluminum silver paste and the aluminum pigment product prepared in the present invention in the UV system blade coating test. In the figure, the commercially available passivated aluminum silver paste is coated in the left area, and the aluminum pigment product prepared in the present invention is coated in the right area.

[0028] Figure 5 This is a comparison chart of the whiteness of commercially available resin-coated aluminum silver paste and the aluminum pigment product prepared in the present invention in the UV system blade coating test. In the figure, the commercially available resin-coated aluminum silver paste is coated in the left area, and the aluminum pigment product prepared in the present invention is coated in the right area. Detailed implementation mode

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0030] The test materials and reagents used in the following embodiments, unless otherwise specified, can be obtained from commercial channels. For those not specified in the embodiments regarding specific technologies or conditions, they can all be carried out according to the technologies or conditions described in the literature in this field or according to the product specifications.

[0031] An aluminum pigment applied to UV coatings is prepared by means of phosphate passivation and is made from the following raw materials in parts by weight:

[0032] 20-30 parts of pigment main body, 40-75 parts of reaction system solvent, 0.01-0.2 part of inhibitor, 0.2-0.5 part of acid treatment agent, 1.5-4.0 parts of active passivator, and 0.3-1.0 part of dispersant;

[0033] Among them, the pigment main body is an oily flaky ball-milled aluminum pigment;

[0034] The reaction system solvent includes acrylate active diluents, methacrylate active diluents, vinyl active diluents, or vinyl polyether active diluents; the acrylate active diluent is a compound system of n-butyl acrylate (BA) and dipropylene glycol diacrylate (DPGDA); in the compound system, the proportion of n-butyl acrylate is 80-85%, and the proportion of dipropylene glycol diacrylate is 15-20%.

[0035] Among them, the solid content of the oily flaky ball-milled aluminum pigment is controlled at 70-80% to reduce the proportion of solvent. The solvent is one or several of D50, D70, 100#, and 150#, the particle size D50 is 11-18 microns, and the particle size span is 0.8-1.0.

[0036] The polymerization inhibitor is hydroquinone monomethyl ether. The addition of the polymerization inhibitor is to prevent the polymerization reaction of the active diluent as the solvent during the passivation process.

[0037] Due to the low surface activity of the oily flaky aluminum pigment, it needs to be acidified before the reaction to increase the active sites on its surface to assist the reaction, so an acidic active substance is selected for pretreatment. Therefore, acrylic acid is used as the acid treatment agent in the present invention.

[0038] The active passivator is one or more of methacryloyloxyethyl phosphate, 2-hydroxyethyl methacrylate phosphate, ethylene glycol methacrylate phosphate, methacryloyloxyethyl succinic acid monoester, and methacryloyloxyethyl maleic acid monoester.

[0039] The dispersant is propylene glycol.

[0040] Example 1

[0041] This example provides a preparation method of aluminum pigment applied to UV coatings, including the following steps:

[0042] (1) Put 50 kg of aluminum pigment into a stainless steel stirring reaction kettle, then add 80 kg of n-butyl acrylate and 20 kg of dipropylene glycol diacrylate, and at the same time add 0.1 kg of hydroquinone monomethyl ether. Set the temperature of the reaction kettle to 45 °C, start stirring, heat up to 50 °C, and after the heating is completed, add 0.5 kg of acrylic acid thereto, and keep stirring for 6 h, and the stirring rate is 500 rpm;

[0043] (2) Prepare 2.5 kg of 2-hydroxyethyl methacrylate phosphate and 1.5 kg of ethylene glycol methacrylate phosphate in advance. After the acid treatment is completed, directly add the prepared 2-hydroxyethyl methacrylate phosphate to the reaction kettle, keep stirring for 30 min, and then add ethylene glycol methacrylate phosphate to the reaction kettle, and keep stirring for 8 h, and the stirring rate is 500 rpm;

[0044] (3) After the stirring is completed, start cooling. When the cooling temperature is lower than 30 °C, use a peristaltic pump to pump the reaction slurry into a filter press for filtration treatment, and then place the filter cake obtained by filtration in an industrial kneading and stirring mixer, add 0.9 kg of dispersant, and adjust the solid content to 25 - 40% with n-butyl acrylate to obtain the finished product.

[0045] Example 2

[0046] This example provides a preparation method of aluminum pigment applied to UV coatings, including the following steps:

[0047] (1) Put 60 kg of aluminum pigment into a stainless - steel stirring reactor, then add 80 kg of n - butyl acrylate and 20 kg of dipropylene glycol diacrylate. At the same time, add 0.2 kg of hydroquinone monomethyl ether. Set the temperature of the reactor to 45 °C, start stirring, and heat up to 50 °C. After the temperature rise ends, add 0.8 kg of acrylic acid and keep stirring for 6 h at a stirring rate of 500 rpm;

[0048] (2) Prepare 5 kg of 2 - hydroxyethyl methacrylate phosphate and 1.5 kg of ethylene glycol methacrylate phosphate in advance. After the acid treatment ends, directly add the pre - prepared 2 - hydroxyethyl methacrylate phosphate into the reactor, keep stirring for 30 min, then add ethylene glycol methacrylate phosphate into the reactor and keep stirring for 8 h at a stirring rate of 500 rpm.

[0049] (3) After the stirring ends, start cooling. When the cooling temperature is lower than 30 °C, use a peristaltic pump to pump the reaction slurry into a filter press for filtration. Then put the filter cake obtained from filtration into an industrial kneading and mixing blender, add 1.5 kg of dispersant and use n - butyl acrylate to adjust the solid content to 25 - 40% to obtain the finished product.

[0050] Example 3

[0051] This example provides a preparation method of aluminum pigment for UV coatings, including the following steps:

[0052] (1) Put 70 kg of aluminum pigment into a stainless - steel stirring reactor, then add 80 kg of n - butyl acrylate and 20 kg of dipropylene glycol diacrylate. At the same time, add 0.35 kg of hydroquinone monomethyl ether. Set the temperature of the reactor to 45 °C, start stirring, and heat up to 50 °C. After the temperature rise ends, add 1.1 kg of acrylic acid and keep stirring for 6 h at a stirring rate of 500 rpm;

[0053] (2) Prepare 7 kg of 2 - hydroxyethyl methacrylate phosphate and 2.1 kg of ethylene glycol methacrylate phosphate in advance. After the acid treatment ends, directly add the pre - prepared 2 - hydroxyethyl methacrylate phosphate into the reactor, keep stirring for 30 min, then add ethylene glycol methacrylate phosphate into the reactor and keep stirring for 8 h at a stirring rate of 500 rpm;

[0054] (3) After the stirring ends, start cooling. When the cooling temperature is lower than 30 °C, use a peristaltic pump to pump the reaction slurry into a filter press for filtration. Then put the filter cake obtained from filtration into an industrial kneading and mixing blender, add 2.1 kg of dispersant and use n - butyl acrylate to adjust the solid content to 25 - 40% to obtain the finished product.

[0055] Comparative Example

[0056] This comparative example provides a preparation method of aluminum pigment. The preparation method is basically the same as that of Example 2, except that: the reaction system solvent in this comparative example only uses a single n-butyl acrylate (BA).

[0057] 1. The performance of the pigment products prepared in the comparative example and the aluminum pigment products prepared in Example 2 was tested and compared. The test results are shown in Table 1.

[0058] Table 1 Comparison of Pigment Performance Tests

[0059]

[0060] It can be seen from the results in Table 1 that the curing rate of the compounding system is increased by 46%, and the alkali resistance is better than that of single BA.

[0061] 2. The acid and alkali resistance tests of the paint film were carried out on the commercially available passivated aluminum silver paste, silica-coated aluminum silver paste and resin-coated aluminum silver paste with the same particle size model (15um) and the aluminum pigment products prepared in Example 2 respectively (the silver paste content is 8%; soaked for 48 hours). The results are as Figure 1 and Figure 2 shown. Figure 1 is the test result of soaking with 5% mass fraction of NaOH aqueous solution. Figure 2 is the test result of soaking with 5% mass fraction of HCl aqueous solution. From left to right in the figure are the commercially available passivated aluminum silver paste, commercially available silica-coated aluminum silver paste, commercially available resin-coated aluminum silver paste and the aluminum pigment products prepared by the present invention.

[0062] According to Figure 1 and Figure 2 results, it can be concluded that the alkali resistance of the present invention in the UV paint film is significantly better than that of conventional passivated and silica-coated aluminum pigments; the acid resistance of the paint film is the same as that of passivated and resin-coated aluminum silver pastes, and is better than that of commercially available silica-coated aluminum pigments.

[0063] 3. The hydrogen evolution acceleration test of the waterborne UV coating system was carried out on the commercially available passivated aluminum silver paste, silica-coated aluminum silver paste with the same particle size model (15um) and the aluminum pigment products prepared by the present invention (the silver paste content is 8%, the total mass is 270g, and the constant temperature test is carried out at 50°C for 20 days (D); since resin-coated aluminum pigments are usually used in oily systems, they are not compared in the waterborne UV system). The results are shown in Table 2.

[0064] Table 2 Hydrogen Evolution Acceleration Test Results of Waterborne UV Coating Systems of Commercially Available Passivated Aluminum Silver Paste, Silica-Coated Aluminum Silver Paste with the Same Particle Size Model (15um) and Aluminum Pigment Products Prepared by the Present Invention (Gas Release Unit: ml)

[0065]

[0066] As can be seen from the results in Table 2, the hydrogen evolution limit value for the conventional plastic paint system in the market is that the gas evolution volume within 7 days is less than 20 ml. From the above results, it can be known that the stability of commercially available silica-coated products and passivated products in waterborne UV coatings is poor and it is difficult to meet the requirements of long-term storage of the waterborne UV resin system in the market. The storage stability of the aluminum pigment finished product prepared in the present invention is significantly better than that of commercially available products and has better stability.

[0067] 4. Conduct a UV system blade coating test (the silver paste content is 10%; waterborne UV resin system, 50-μm wet film applicator, unit: mg / kg) on commercially available passivated aluminum silver paste, silica-coated aluminum silver paste, resin-coated aluminum silver paste with the same particle size model (15 μm) and the aluminum pigment finished product prepared in Example 2 of the present invention. The specific method is as follows: conduct a comparative test on the same test board. Drop the above-mentioned commercially available aluminum pigments (passivated aluminum silver paste, silica-coated aluminum silver paste or resin-coated aluminum silver paste) on the left side of the test board and drop the aluminum pigment finished product prepared in the present invention on the right side, then scrape and coat evenly from top to bottom with a blade, and conduct whiteness comparison and brightness comparison after drying; since conventional aluminum pigments need to be diluted before use, the same active diluent used in the present invention is used as the diluting solvent. In addition, in order to more intuitively conduct hue comparison, aluminum pigments with a higher amount than the normal market usage amount are added in this test and the curing time is extended to ensure complete curing.

[0068] Table 3 Comparison results of UV system blade coating test

[0069]

[0070] Note: Among them, L* represents lightness, and its value range is from 0 (black) to 100 (white), which is used to describe the brightness of the color; a * represents the color component from green to red; b * represents the color component from blue to yellow; C * refers to the chroma of the color, also called saturation; h represents the hue angle; Si represents the reflectivity and transmittance of the coating; Sa represents the average surface roughness at different angles; G represents the glossiness.

[0071] According to Figures 3 - 5 the hue comparison and the results in Table 3, it can be known that the aluminum pigment finished product prepared in the present invention has the same hue as the conventional passivated product, and its whiteness is significantly better than that of commercially available passivated aluminum silver paste, silica-coated aluminum silver paste, and resin-coated aluminum silver paste; the brightness of the aluminum pigment finished product prepared in the present invention is significantly better than that of commercially available silica-coated and resin-coated aluminum pigments.

[0072] Based on the above conclusions, the present invention uses an active passivator to treat the surface of aluminum pigments, enabling them to participate in the overall polymerization reaction of the coating during the UV curing process, so as to completely integrate with the coating and improve the performance of the paint film. At the same time, by selecting a suitable active diluent to replace solvents such as alcohols, ethers, and water as the main solvent for waterborne aluminum pigments, on the basis of retaining the flexibility of n-butyl acrylate and the compatibility with aluminum pigments, dipropylene glycol diacrylate is introduced. Through the synergistic effect of functional groups, the crosslinking density and curing rate are increased, enabling it to directly participate in the UV coating curing process without pre-baking. While reducing the VOC emissions during construction, lowering the construction energy consumption, and reducing the construction time, it does not affect the metallic texture and corrosion resistance of aluminum pigments.

[0073] The embodiments disclosed in the present invention are preferred embodiments, but not limited thereto. Those of ordinary skill in the art can easily understand the spirit of the present invention based on the above embodiments and make different extensions and changes. However, as long as they do not depart from the spirit of the present invention, they are within the protection scope of the present invention.

Claims

1. An aluminum pigment applied to UV coatings, characterized in that, It consists of the following raw materials in parts by weight: 20 - 30 parts of pigment main body, 40 - 75 parts of reaction system solvent, 0.01 - 0.2 part of inhibitor, 0.2 - 0.5 part of acid treatment agent, 1.5 - 4.0 parts of active passivator, and 0.3 - 1.0 part of dispersant; Among them, the pigment main body is an oily flaky ball - milled aluminum pigment; The reaction system solvent includes acrylate - type active diluent, methacrylate - type active diluent, vinyl - type active diluent or vinyl polyether - type active diluent; The acrylate - type active diluent is a compounding system of n - butyl acrylate and dipropylene glycol diacrylate; in the compounding system, the proportion of n - butyl acrylate is 80 - 85%, and the proportion of dipropylene glycol diacrylate is 15 - 20%.

2. The aluminum pigment applied to the UV coating according to claim 1, wherein: The solid content of the oily flaky ball - milled aluminum pigment is controlled at 70 - 80% to reduce the proportion of solvent. The solvent is one or several of D50, D70, 100#, 150#, the particle size D50 is 11 - 18 microns, and the particle size span is 0.8 - 1.

0.

3. The aluminum pigment applied to the UV coating according to claim 1, characterized in that: The inhibitor is hydroquinone monomethyl ether.

4. The aluminum pigment applied to the UV coating according to claim 1, characterized in that: The acid treatment agent is acrylic acid.

5. The aluminum pigment applied to the UV coating according to claim 1, characterized in that: The active passivator is one or more of methacryloyloxyethyl phosphate, 2 - hydroxyethyl methacrylate phosphate, ethylene glycol methacrylate phosphate, methacryloyloxyethyl succinic acid monoester, methacryloyloxyethyl maleic acid monoester.

6. The aluminum pigment applied to the UV coating according to claim 1, characterized in that: The dispersant is propylene glycol.

7. A preparation method of an aluminum pigment applied to a UV coating as described in any one of claims 1-6, characterized in that, It includes the following steps: (1) According to the proportion, put the pigment main body into a stainless - steel stirring reaction kettle, then add the reaction system solvent and the inhibitor, set the temperature of the reaction kettle to 45°C, start stirring and heating. After the heating is completed, add the acid treatment agent to it, and keep it warm and stir for a period of time; (2) After the acid treatment is completed, take a part of the pre - prepared active passivator and add it to the reaction kettle, keep it warm and stir for 30 min. Then add the remaining part of the active passivator to the reaction kettle and keep it warm and stir for a period of time to fully passivate the aluminum flakes with the phosphate ester; (3) After the stirring is completed, start to cool. When the cooling temperature is lower than 30°C, use a peristaltic pump to pump the reaction slurry into a filter press for filtration treatment. Then place the filter cake obtained by filtration in an industrial kneading and stirring mixer, add the dispersant and use the reaction system solvent to adjust the solid content to 25 - 40% to obtain the finished product.

8. The preparation method of the aluminum pigment applied to the UV coating according to claim 7, characterized in that: In step (1), the maximum temperature of heating is 50°C.

9. The preparation method of the aluminum pigment applied to the UV coating according to claim 7, characterized in that: In step (1), the holding and stirring time is 3 - 6 h, and the stirring rate is 500 - 800 rpm.

10. The preparation method of the aluminum pigment applied to the UV coating according to claim 7, characterized in that: In step (2), the holding and stirring time is 6 - 8 h, and the stirring rate is 500 - 800 rpm.

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