A kind of water-based UV paint and preparation method thereof

Abstract

The present invention relates to the technical field of water-based UV paints, and specifically discloses a water-based UV paint and a preparation method thereof. The water-based UV paint comprises a polyurethane acrylic emulsion, a wetting and leveling agent, a photoinitiator, a thickener, a polyethylene wax paste, a water-based aluminum silver paste, diethylene glycol butyl ether, dipropylene glycol methyl ether acetate, a dialkyl dithiocarbamate, a pigment, and water. The polyurethane acrylic emulsion comprises 35%-45% polyurethane, 10%-20% acrylic acid, and 40%-50% water; and the photoinitiator is a mixture of 4-methylbenzophenone and 2,4,6-trimethylbenzophenone in a mass ratio of 1:(1.8-2.2). The water-based UV paint of the present application has good performance in terms of curing, curing depth, and adhesion.

Description

Technical Field

[0001] The invention relates to the technical field of water-based UV paint, in particular to a water-based UV paint and a preparation method thereof. Background Art

[0002] Amid growing global environmental awareness, water-based UV coatings, as a green and environmentally friendly coating technology, are gaining market favor. These coatings are not only non-toxic, harmless, non-flammable, and non-explosive, but also meet current high environmental standards. However, the development of water-based UV coating technology is still in a stage of continuous improvement and innovation.

[0003] Currently, water-based UV paints on the market generally face the problem of not being able to cure dark colors. This is mainly due to the strong absorption of ultraviolet light by dark pigments, resulting in incomplete deep-layer curing of the coating. The ultraviolet absorption properties of dark pigments also limit the curing depth of water-based UV paints. Currently, the cured film thickness of water-based UV paints on the market can only be controlled to 6-8μm, which restricts its scope of application. In addition, incomplete curing of water-based UV paints directly affects the adhesion stability of the paint film, which in turn affects the durability and aesthetics of the paint film. Some water-based UV paints on the market currently improve the curing effect by adjusting the type and dosage of photoinitiators. However, even so, after adding dark pigments, these water-based UV paints still struggle to achieve the ideal cure depth. The content of dark pigments in the vast majority of water-based UV paints on the market currently only accounts for the top 2%, which is far from meeting the market demand for dark paint films.

[0004] Therefore, it is necessary to provide a water-based UV paint that can effectively solve the problem of dark pigment curing, so as to improve the curing depth and adhesion of the paint film, expand the application range of water-based UV paint, and meet the market demand for dark paint films. Summary of the Invention

[0005] To effectively address the curing issues of dark pigments, this application provides a water-based UV paint and a preparation method thereof. By employing a specific polyurethane acrylic emulsion, a photoinitiator, diethylene glycol butyl ether, dipropylene glycol methyl ether acetate, and a dialkyl dithiocarbamate compound, this application achieves significant improvements in the curing, curing depth, and adhesion of the water-based UV paint.

[0006] In the first aspect, the present application provides a water-based UV paint using the following technical solution:

[0007] A water-based UV paint comprises the following raw materials in percentage by mass: 60%-70% polyurethane acrylic emulsion, 1%-2% wetting and leveling agent, 2%-3% photoinitiator, 1%-2% thickener, 2%-3% polyethylene wax paste, 5%-7% water-based aluminum silver paste, 2%-3% diethylene glycol butyl ether, 2%-3% dipropylene glycol methyl ether acetate, 1%-2% dialkyl dithiocarbamate, 0-6% pigment, and the balance is water;

[0008] Calculated by mass percentage of the polyurethane acrylic emulsion, the polyurethane acrylic emulsion comprises 35%-45% polyurethane, 10%-20% acrylic acid and 40%-50% water;

[0009] The photoinitiator is a mixture of 4-methylbenzophenone and 2,4,6-trimethylbenzophenone, and the mass ratio of the 4-methylbenzophenone to the 2,4,6-trimethylbenzophenone is 1:(1.8-2.2).

[0010] In the above technical solution, this application specifically defines the ratio of polyurethane acrylic emulsion and photoinitiator, and adds diethylene glycol butyl ether, dipropylene glycol methyl ether acetate and dialkyl dithiocarbamate to assist film formation and curing, thereby ensuring that in the presence of dark pigments, the photoinitiator can more effectively absorb ultraviolet rays and initiate polymerization reactions, thereby increasing the curing depth of the paint film, so that the paint film has a wider curing depth and better adhesion.

[0011] Preferably, the mass ratio of 4-methylbenzophenone to 2,4,6-trimethylbenzophenone is 1:2.

[0012] In the above technical solution, the present application further optimizes the ratio of the photoinitiator by specifically limiting the mass ratio of 4-methylbenzophenone and 2,4,6-trimethylbenzophenone to 1:2, further promotes the coordination effect between the photoinitiator and other components in the water-based UV paint, so that the photoinitiator can more efficiently initiate the polymerization reaction after absorbing ultraviolet rays, thereby improving the curing speed and curing depth of the paint film.

[0013] Preferably, the mass ratio of diethylene glycol butyl ether, dipropylene glycol methyl ether acetate and dialkyl dithiocarbamate is 2.5:2.2:1.5.

[0014] In the above technical solution, the present application further optimizes the ratio of auxiliary film-forming curing agents by further limiting the mass ratio of diethylene glycol butyl ether, dipropylene glycol methyl ether acetate and dialkyl dithiocarbamate to 2.5:2.2:1.5, ensuring that in the presence of dark pigments, these auxiliary film-forming curing agents can more effectively synergize with the photoinitiator, thereby improving the curing uniformity and adhesion of the paint film.

[0015] Preferably, the polyurethane acrylic emulsion comprises 40% polyurethane, 15% acrylic acid and 45% water in terms of mass percentage of the polyurethane acrylic emulsion.

[0016] In the above technical solution, the present application ensures that the paint film has good curing effect and adhesion by further limiting the content of each component in the polyurethane acrylic emulsion.

[0017] Preferably, the wetting and leveling agent is polyether-modified silicone.

[0018] In the above technical solution, this application reduces the surface tension of water-based UV paint by limiting the wetting and leveling agent to polyether-modified silicone, further improves the leveling and glossiness of the paint film, makes the paint film surface smoother and more uniform, and improves the overall aesthetics of the paint film.

[0019] Preferably, the thickener is a nonionic polyurethane associative thickener.

[0020] In the above technical solution, this application further enhances the stability and anti-sagging properties of the paint film by limiting the thickener to a non-ionic polyurethane associative thickener, making it less likely for the paint film to sag during construction and improving the construction quality.

[0021] In a second aspect, the present application provides a method for preparing a water-based UV paint using the following technical solution:

[0022] A method for preparing a water-based UV paint comprises the following steps:

[0023] Step 1: Take polyurethane acrylic emulsion, add wetting and leveling agent while stirring, and stir evenly to obtain a base material; take diethylene glycol butyl ether, dipropylene glycol methyl ether acetate, dialkyl dithiocarbamate and photoinitiator, stir until completely melted, and obtain preparation 1; mix water-based aluminum silver paste, pigment and water, and stir evenly to obtain preparation 2;

[0024] Step 2: Add ingredient 1 to the base and mix well;

[0025] Step 3: Add polyethylene wax slurry and stir evenly;

[0026] Step 4: Add ingredients 2 and mix well;

[0027] Step 5: Add thickener and stir evenly to obtain water-based UV paint.

[0028] In the above technical solution, the present application provides a method for preparing a water-based UV paint, which is simple, efficient and suitable for industrial production.

[0029] Preferably, the stirring speed of step 1, step 2, step 3, step 4 and step 5 is 400-500 rpm.

[0030] In the above technical solution, the present application ensures that the components can be fully mixed during the preparation process by limiting the stirring speed to 400-500rpm, while avoiding the destruction of the emulsion caused by excessive shear force, thereby ensuring the stability and uniformity of the water-based UV paint.

[0031] In a third aspect, the present application provides a method for using a water-based UV paint using the following technical solution:

[0032] A method for using a water-based UV paint comprises: applying the water-based UV paint evenly on a surface to be painted by a brush, roller or spray, performing radiation curing on the applied water-based UV paint by an ultraviolet light source, and obtaining a UV paint layer after drying.

[0033] In the above technical solution, the present application obtains the paint film by UV curing, meeting the market demand for dark paint films.

[0034] In summary, this application has the following beneficial technical effects:

[0035] 1. This application improves the curing depth of the paint film by adopting a compound of a specific polyurethane acrylic emulsion, a photoinitiator, diethylene glycol butyl ether, dipropylene glycol methyl ether acetate and dialkyl dithiocarbamate, so that the paint film has a wider curing depth and better adhesion.

[0036] 2. The dark pigment addition amount of the water-based UV paint of the present application can reach 6%, which is significantly higher than the water-based UV paint on the market. DETAILED DESCRIPTION

[0037] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0038] Example 1

[0039] A water-based UV paint comprises polyurethane acrylic emulsion, a wetting and leveling agent, a photoinitiator, a thickener, polyethylene wax slurry, water-based aluminum silver slurry, diethylene glycol butyl ether, dipropylene glycol methyl ether acetate, dialkyl dithiocarbamate, pigment and water.

[0040] The polyurethane acrylic emulsion contains 40% polyurethane, 15% acrylic acid and 45% water.

[0041] The photoinitiator is a mixture of 4-methylbenzophenone and 2,4,6-trimethylbenzophenone in a mass ratio of 1:2.

[0042] Among them, the wetting and leveling agent is polyether modified silicone, specifically BYK-370 from Germany.

[0043] The thickener is a nonionic polyurethane associative thickener, specifically Hemmings RHEOLATE 299.

[0044] The polyethylene wax slurry is specifically BYK-513 polyethylene wax emulsion.

[0045] The water-based aluminum silver paste is specifically Eckart aluminum pigment PC 100.

[0046] Among them, the CAS number of diethylene glycol butyl ether is: 112-34-5.

[0047] Among them, the CAS number of dipropylene glycol methyl ether acetate is: 88917-22-0.

[0048] Among them, the CAS number of dialkyl dithiocarbamate is: 10254-57-6.

[0049] The pigment is a black pigment, specifically Columbia, brand Raven 5000.

[0050] The preparation method of water-based UV paint comprises the following steps:

[0051] Step 1:

[0052] a: Take polyurethane acrylic emulsion, add wetting and leveling agent while stirring at 450 rpm, and continue stirring for 4 minutes after adding to obtain the base material.

[0053] b: Take diethylene glycol butyl ether, dipropylene glycol methyl ether acetate, dialkyl dithiocarbamate and photoinitiator, mix, and stir at 450 rpm for 18 minutes to obtain preparation 1.

[0054] c: Mix the aqueous aluminum-silver paste, pigment and water, and stir at 450 rpm for 4 minutes to obtain material 2.

[0055] Step 2: Add material 1 to the base material and stir at 450 rpm for 4 minutes.

[0056] Step 3: Add polyethylene wax slurry and stir at 450 rpm for 4 minutes.

[0057] Step 4: Add material 2 and stir at 450 rpm for 6 minutes.

[0058] Step 5: Add thickener and stir at 450 rpm for 12 minutes to obtain water-based UV paint.

[0059] Example 2

[0060] A water-based UV paint, which differs from Example 1 in that it comprises: polyurethane acrylic emulsion, a wetting and leveling agent, a photoinitiator, a thickener, polyethylene wax slurry, water-based aluminum silver paste, diethylene glycol butyl ether, dipropylene glycol methyl ether acetate, dialkyl dithiocarbamate, pigment, and water.

[0061] The polyurethane acrylic emulsion contains 35% polyurethane, 20% acrylic acid and 45% water.

[0062] The photoinitiator is a mixture of 4-methylbenzophenone and 2,4,6-trimethylbenzophenone in a mass ratio of 1:1.8.

[0063] The preparation method of water-based UV paint comprises the following steps:

[0064] Step 1:

[0065] a: Take polyurethane acrylic emulsion, add wetting and leveling agent while stirring at 400 rpm, and continue stirring for 5 minutes after adding to obtain the base material.

[0066] b: Take diethylene glycol butyl ether, dipropylene glycol methyl ether acetate, dialkyl dithiocarbamate and photoinitiator, mix, and stir at 400 rpm for 20 minutes to obtain preparation 1.

[0067] c: Mix the aqueous aluminum silver paste, pigment and water, and stir at 400 rpm for 5 minutes to obtain material 2.

[0068] Step 2: Add material 1 to the base material and stir at 400 rpm for 5 minutes.

[0069] Step 3: Add polyethylene wax slurry and stir at 400 rpm for 5 minutes.

[0070] Step 4: Add material 2 and stir at 400 rpm for 8 minutes.

[0071] Step 5: Add thickener and stir at 400 rpm for 15 minutes to obtain water-based UV paint.

[0072] Example 3

[0073] A water-based UV paint, which differs from Example 1 in that it comprises: polyurethane acrylic emulsion, a wetting and leveling agent, a photoinitiator, a thickener, polyethylene wax slurry, water-based aluminum silver paste, diethylene glycol butyl ether, dipropylene glycol methyl ether acetate, dialkyl dithiocarbamate, pigment, and water.

[0074] The polyurethane acrylic emulsion contains 45% polyurethane, 10% acrylic acid and 45% water.

[0075] The photoinitiator is a mixture of 4-methylbenzophenone and 2,4,6-trimethylbenzophenone in a mass ratio of 1:2.2.

[0076] The preparation method of water-based UV paint comprises the following steps:

[0077] Step 1:

[0078] a: Take polyurethane acrylic emulsion, add wetting and leveling agent while stirring at 500 rpm, and continue stirring for 3 minutes after adding to obtain the base material.

[0079] b: Take diethylene glycol butyl ether, dipropylene glycol methyl ether acetate, dialkyl dithiocarbamate and photoinitiator, mix, and stir at 500 rpm for 15 minutes to obtain preparation 1.

[0080] c: Mix the aqueous aluminum-silver paste, pigment and water, and stir at 500 rpm for 3 minutes to obtain material 2.

[0081] Step 2: Add material 1 to the base material and stir at 500 rpm for 3 minutes.

[0082] Step 3: Add polyethylene wax slurry and stir at 500 rpm for 3 minutes.

[0083] Step 4: Add material 2 and stir at 500 rpm for 5 minutes.

[0084] Step 5: Add thickener and stir at 500 rpm for 10 minutes to obtain water-based UV paint.

[0085] The amounts of raw materials used in Examples 1-3 are shown in Table 1.

[0086] Table 1:

[0087]

[0088] Examples 4-7

[0089] A water-based UV paint, which is different from Example 1 in that the amount of pigment used is different.

[0090] The amounts of raw materials used in Examples 4-7 are shown in Table 2.

[0091]

[0092] Comparative Example 1

[0093] A water-based UV paint, which is different from Example 1 in that the polyurethane acrylic emulsion is RA7004 water-based polyurethane emulsion produced by Mitsui Chemicals of Japan.

[0094] Comparative Example 2

[0095] A water-based UV paint, which is different from Example 1 in that the photoinitiator is 4-methylbenzophenone.

[0096] Comparative Example 3

[0097] A water-based UV paint, which is different from Example 1 in that the photoinitiator is 2,4,6-trimethylbenzophenone.

[0098] Comparative Example 4

[0099] A water-based UV paint is disclosed. Different from Example 1, the photoinitiator is a mixture of 4-methylbenzophenone and 2,4,6-trimethylbenzophenone in a mass ratio of 1:1.5.

[0100] Comparative Example 5

[0101] A water-based UV paint, which is different from Example 1 in that the photoinitiator is a mixture of 4-methylbenzophenone and 2,4,6-trimethylbenzophenone in a mass ratio of 1:2.5.

[0102] Comparative Example 6

[0103] A water-based UV paint, which is different from Example 1 in that an equal amount of diethylene glycol butyl ether is replaced by dipropylene glycol methyl ether.

[0104] Comparative Example 7

[0105] A water-based UV paint, which is different from Example 1 in that dipropylene glycol methyl ether acetate is replaced by propylene glycol methyl ether acetate in an equal amount.

[0106] Comparative Example 8

[0107] A water-based UV paint, which is different from Example 1 in that an equal amount of dialkyl dithiocarbamate is replaced by isopentyl p-dimethylaminobenzoate.

[0108] Control Example

[0109] A commercially available black water-based UV paint.

[0110] Cure depth detection: The colored paints of the above-mentioned embodiments and comparative examples were applied to the surface of an ABS substrate, and the test was started from a cure depth of 4 μm with a test gradient of 1 μm. The cure depth of the previous gradient when the hardness of the paint film measured by a hardness meter dropped significantly was recorded as the cure depth.

[0111] Curing time detection: The paint film thickness is 4μm, the ultraviolet light intensity is 600mj / cm2, and the paint film curing time is recorded.

[0112] Adhesion test: The paint film thickness is 4μm, and a 100-grid test is used, with 3M tape being pulled continuously for more than 3 times. The evaluation levels are as follows:

[0113] 5B: The edges of the lines are smooth, and there is no paint peeling at the edges and intersections of the lines.

[0114] 4B: Small pieces of paint have fallen off at the intersections of the lines, and the total area of ​​the paint has fallen off is less than 5%.

[0115] 3B: Small pieces of paint are peeling off at the edges and intersections of the lines, and the total peeling area is between 5% and 15%.

[0116] 2B: There are pieces of paint peeling off at the edges and intersections of the lines, and the total peeling area is between 15% and 35%.

[0117] 1B: There are pieces of paint peeling off at the edges and intersections of the lines, and the total peeling area is between 35% and 65%.

[0118] 0B: The shedding area exceeds the 1B standard.

[0119] Alcohol resistance test: Use a cotton swab dipped in anhydrous alcohol to wipe 500 times with a load of 2.5 kg / force, and observe whether there is any color change.

[0120] The above test results are shown in Table 3.

[0121] Table 3:

[0122]

[0123] The above test results show that the water-based UV paints of Examples 1 to 7 all exhibit good performance in terms of curing depth range, curing time, adhesion, and alcohol resistance. It can be seen that when the black pigment addition amount of the water-based UV paint of the present application is between 2% and 6%, the curing depth of the water-based UV paint of the present application can reach 12-16 μm.

[0124] Specifically combining the analysis of Example 1 and Comparative Examples 1-8, it is not difficult to see that the water-based UV paint of Example 1 shows good performance in terms of curing depth range, curing time, adhesion and alcohol resistance. It can be seen that only by using a specific polyurethane acrylic emulsion, photoinitiator, diethylene glycol butyl ether, dipropylene glycol methyl ether acetate and dialkyl dithiocarbamate compound can the water-based UV paint be significantly improved in curing, curing depth and adhesion.

[0125] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A water-based UV paint, characterized in that: The invention comprises the following raw materials in percentage by weight: 60%-70% polyurethane acrylic emulsion, 1%-2% wetting and leveling agent, 2%-3% photoinitiator, 1%-2% thickener, 2%-3% polyethylene wax paste, 5%-7% water-based aluminum silver paste, 2%-3% diethylene glycol butyl ether, 2%-3% dipropylene glycol methyl ether acetate, 1%-2% dialkyl dithiocarbamate, 0-6% pigment, and the balance is water; Calculated by mass percentage of the polyurethane acrylic emulsion, the polyurethane acrylic emulsion comprises 35%-45% polyurethane, 10%-20% acrylic acid and 40%-50% water; The photoinitiator is a mixture of 4-methylbenzophenone and 2,4,6-trimethylbenzophenone, and the mass ratio of the 4-methylbenzophenone to the 2,4,6-trimethylbenzophenone is 1:(1.8-2.2).

2. A water-based UV paint according to claim 1, characterized in that: The mass ratio of the 4-methylbenzophenone to the 2,4,6-trimethylbenzophenone is 1:

2.

3. A water-based UV paint according to claim 1, characterized in that: The mass ratio of diethylene glycol butyl ether, dipropylene glycol methyl ether acetate and dialkyl dithiocarbamate is 2.5:2.2:1.

5.

4. A water-based UV paint according to claim 1, characterized in that: Calculated by mass percentage, the polyurethane acrylic emulsion comprises 40% polyurethane, 15% acrylic acid and 45% water.

5. A water-based UV paint according to claim 1, characterized in that: The wetting and leveling agent is polyether-modified silicone.

6. A water-based UV paint according to claim 1, characterized in that: The thickener is a nonionic polyurethane associative thickener.

7. A method for preparing a water-based UV paint according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Take polyurethane acrylic emulsion, add wetting and leveling agent while stirring, and stir evenly to obtain a base material; take diethylene glycol butyl ether, dipropylene glycol methyl ether acetate, dialkyl dithiocarbamate and photoinitiator, stir until completely melted, and obtain preparation 1; mix water-based aluminum silver paste, pigment and water, and stir evenly to obtain preparation 2; Step 2: Add ingredient 1 to the base and mix well; Step 3: Add polyethylene wax slurry and stir evenly; Step 4: Add ingredients 2 and mix well; Step 5: Add thickener and stir evenly to obtain water-based UV paint.

8. The method for preparing a water-based UV paint according to claim 7, characterized in that: The stirring speed of step 1, step 2, step 3, step 4 and step 5 is 400-500 rpm.

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