Baking type water-based single-component acrylic acid effect pigment coating and preparation method thereof

Abstract

The invention relates to the field of water-based paint, and particularly discloses baking type water-based single-component acrylic acid effect pigment paint and a preparation method thereof. The baking type water-based single-component acrylic acid effect pigment coating is prepared from the following raw materials in percentage: 55 to 65 percent of acrylic acid core-shell emulsion, 1 to 2 percent of N, N-dimethylethanolamine, 1 to 5 percent of partially methylated amino resin, 1 to 5 percent of ethylene glycol butyl ether, 1 to 3 percent of dipropylene glycol butyl ether, 10 to 15 percent of absolute ethyl alcohol, 1 to 4 percent of auxiliaries, 6 to 10 percent of effect pigment and the balance of water. The acrylic core-shell emulsion and the amino resin are cross-linked to form a compact network structure, so that directional arrangement of the effect pigment is promoted, the phenomena of floating and spots of the pigment on the surface of a coating are reduced, and the directional effect of the effect pigment in the coating is improved.

Description

Technical Field

[0001] This application relates to the field of waterborne coatings, and in particular to a baking-type waterborne single-component acrylic effect pigment coating and its preparation method. Background Technology

[0002] In the field of coating technology, with the continuous development of industry and the gradual enhancement of people's environmental awareness, water-based coatings have been increasingly widely used in many fields due to their advantages such as low volatile organic compound (VOC) emissions, providing beautiful and durable protective coatings for products in various industries.

[0003] Traditional solvent-based effect coatings have high solvent content, with most solvents being xylene, butyl acetate, etc., which does not conform to the trend of environmental protection. However, water-based effect pigment coatings currently on the market have defects such as poor orientation, easy blackening and mottling of the surface, rough appearance, and poor decorative properties. Summary of the Invention

[0004] In order to improve the overall performance of existing waterborne effect pigment coatings, this application provides a baking-type waterborne single-component acrylic effect pigment coating and its preparation method.

[0005] In a first aspect, this application provides a baking-type water-based single-component acrylic effect pigment coating, which adopts the following technical solution: A baking-type waterborne one-component acrylic effect pigment coating comprises the following percentages of raw materials: 55-65% acrylic core-shell emulsion, 1-2% N,N-dimethylethanolamine, 1-5% partially methylated amino resin, 1-5% ethylene glycol butyl ether, 1-3% dipropylene glycol butyl ether, 10-15% anhydrous ethanol, 1-4% additives, 6-10% effect pigment, and the balance being water.

[0006] By adopting the above technical solution, acrylic core-shell emulsion can provide rapid initial curing of coatings with its own hard core, fix the position of effect pigments, and enhance the film-forming fluidity of coatings and promote the directional arrangement of effect pigments. The acrylic core-shell emulsion introduces carboxyl groups to crosslink with amino resins to form a dense network structure, which prevents pigment displacement and reduces the phenomenon of pigment blooming and spots on the coating surface. Through the dual action, acrylic core-shell emulsion can improve the directional effect of effect pigments in coatings.

[0007] Partially methylated amino resins exhibit higher reactivity than fully methylated amino resins, enabling them to form a denser cross-linked structure with acrylic core-shell emulsions. This enhances coating hardness and stability while reducing pigment migration. The synergistic use of anhydrous ethanol, ethylene glycol butyl ether, and dipropylene glycol butyl ether allows for faster initial drying with anhydrous ethanol, reducing pigment settling, while dipropylene glycol butyl ether improves coating leveling, resulting in enhanced coating uniformity and smoothness.

[0008] Preferably, the acrylic core-shell emulsion comprises the following raw materials in parts by weight: 80-100 parts water, 7-10 parts butyl acrylate, 7-10 parts methyl methacrylate, 0.2-0.7 parts hydroxypropyl acrylate, 1-2 parts hydroxyethyl acrylate, 0.5-1 part acrylic acid, 1-3 parts methacrylic acid, 0.1-0.3 parts ammonium persulfate initiator, and 0.5-1 parts reactive emulsifier.

[0009] By adopting the above technical solution, methyl methacrylate, as a hard monomer, can form rigid segments through free radical polymerization, thereby improving the hardness and wear resistance of the coating. Butyl acrylate improves the flexibility of the coating, while methyl methacrylate improves the weather resistance and gloss of the coating. The two work synergistically to improve the hardness and wear resistance of the coating. The copolymerization of butyl acrylate with acrylic acid, methacrylic acid, hydroxypropyl acrylate, hydroxyethyl acrylate, and methyl methacrylate provides better film-forming flowability, reduces surface roughness of the coating, enhances the flexibility and adhesion of the coating, and promotes easier orientation of effect pigments under spray shear force, thus improving the decorative effect of the coating surface.

[0010] Preferably, the preparation method of the acrylic core-shell emulsion includes the following specific steps: the raw materials of the acrylic core-shell emulsion are divided into two parts. In one part, water and emulsifier are mixed and heated, and butyl acrylate, methyl methacrylate, hydroxypropyl acrylate, methacrylic acid, and ammonium persulfate initiator are added dropwise and mixed evenly to obtain a core monomer emulsion. The remaining water, emulsifier, acrylic acid, methacrylic acid, butyl acrylate, methyl methacrylate, hydroxyethyl acrylate, and ammonium persulfate initiator are mixed to obtain a shell monomer emulsion. The shell monomer emulsion is added to the core monomer emulsion and kept at a constant temperature for reaction to finally obtain the acrylic core-shell emulsion.

[0011] Preferably, the heating temperature is 60-90℃.

[0012] Preferably, the effect pigment is one of pearlescent powder and aluminum powder, and the additive is vinyltriethoxysiloxane.

[0013] By adopting the above technical solution, vinyltriethoxysiloxane, as an additive, can participate in the polymerization reaction of acrylic acid using its own vinyl groups. At the same time, the alkoxy groups of vinyltriethoxysiloxane can be grafted onto the surface of the pigment, thereby establishing a bridge between the pigment and the polymer, promoting the two to be tightly bonded together, enhancing the compatibility between the pigment and the polymer, and enabling the pigment to be uniformly and firmly dispersed in the coating system.

[0014] Preferably, the surface of the effect pigment is coated with both silica sol and additives.

[0015] Preferably, the method for double coating the effect pigment surface includes the following specific steps: Tetraethyl orthosilicate, additives, and anhydrous ethanol are mixed to form solution A. Then, ammonia, water, and anhydrous ethanol are mixed to form solution B. The effect pigment is mixed with anhydrous ethanol to form a pigment solution. The mixture is stirred evenly under nitrogen protection. After heating the pigment solution, solutions A and B are added dropwise. The reaction is maintained at this temperature. After filtration and drying, the double-coated effect pigment is obtained.

[0016] By employing the above technical solution, tetraethyl orthosilicate and vinyltriethoxysiloxane condense with each other and then with the hydroxyl groups on the pigment surface, forming a dense vinyl silica sol film on the pigment surface. This promotes the firm and uniform dispersion of the effect pigment in the coating system, improves the orientation effect of the effect pigment in the coating, and maintains a good gloss level in the coating. Introducing organic polymers and silica sol through in-situ polymerization on the effect pigment surface enhances the compatibility between the effect pigment and the organic matrix, as well as the adhesion of the effect pigment to the coating, reduces the sedimentation of the effect pigment in the coating system, and promotes the formation of a smooth and glossy coating.

[0017] Preferably, the mass ratio of the total mass of the tetraethyl orthosilicate, ammonia, water, effect pigment and anhydrous ethanol is (2-3):(3-5):2:(50-80).

[0018] Preferably, the heating temperature is 150-160℃.

[0019] Secondly, this application provides a method for preparing a baking-type waterborne single-component acrylic effect pigment coating, using the following technical solution: A method for preparing a baking-type waterborne single-component acrylic effect pigment coating includes the following specific steps: Acrylic core-shell emulsion, N,N-dimethylethanolamine, and water are mixed in advance and stirred evenly. Then, a portion of methylated amino resin, ethylene glycol butyl ether, dipropylene glycol butyl ether, anhydrous ethanol, additives, and effect pigments are added and mixed to obtain a baking-type waterborne one-component acrylic effect pigment coating.

[0020] By adopting the above technical solution, the synergistic effect of each component can improve the orientation effect of the effect pigment, form a smooth and uniform coating, and reduce the occurrence of mottling and spots on the coating.

[0021] In summary, this application has the following beneficial effects: 1. Because this application uses an acrylic core-shell emulsion with a hard core and a soft shell, it promotes the directional alignment of effect pigments and reduces pigment blooming and spotting on the coating surface. Simultaneously, the acrylic core-shell emulsion introduces carboxyl groups to crosslink with amino resins, forming a dense network structure that improves the coating's hardness and abrasion resistance. The synergistic use of anhydrous ethanol, ethylene glycol butyl ether, and dipropylene glycol butyl ether improves the coating's fluidity and enhances its gloss and smoothness.

[0022] 2. This application uses pearlescent powder and aluminum powder as effect pigments, and simultaneously uses vinyltriethoxysiloxane and silica sol to double-coat the pigment surface, forming a dense vinyl silica sol film on the pigment surface. This improves the pigment orientation effect of the coating, reduces the occurrence of mottling and spots in the coating, and maintains a good gloss. By introducing organic polymers and silica sol through in-situ polymerization on the pigment surface, the pigment is firmly and uniformly dispersed in the coating system, reducing pigment sedimentation and promoting the formation of a smooth and glossy coating. Detailed Implementation

[0023] The present application will be further described in detail below with reference to the embodiments.

[0024] All raw materials used in the examples are commercially available. Example

[0025] Example 1 This embodiment provides a baking-type waterborne one-component acrylic effect pigment coating, comprising the following percentages of raw materials: 60% acrylic core-shell emulsion, 1.5% N,N-dimethylethanolamine, 3% partially methylated amino resin, 3% ethylene glycol butyl ether, 2% dipropylene glycol butyl ether, 13% anhydrous ethanol, 3% additives, 8% effect pigment, and the balance being water. The partially methylated amino resin is 625 amino resin purchased from Changchun Artificial Resin Factory Co., Ltd., the effect pigment is pearlescent powder with an average particle size of 10 μm, and the additive is vinyltriethoxysiloxane.

[0026] The acrylic core-shell emulsion comprises the following raw materials in parts by weight: 90 kg water, 8 kg butyl acrylate, 8 kg methyl methacrylate, 0.5 kg hydroxypropyl acrylate, 1.5 kg hydroxyethyl acrylate, 0.8 kg acrylic acid, 2 kg methacrylic acid, 0.2 kg ammonium persulfate initiator, and 0.7 kg reactive emulsifier. The reactive emulsifier is ADEKAREASOAP SR-10, and the initiator is ammonium persulfate.

[0027] A method for preparing a baking-type waterborne single-component acrylic effect pigment coating includes the following specific steps: S1: Divide each raw material of the acrylic core-shell emulsion into two equal parts. Heat the water and emulsifier of one part to 75°C, and then add butyl acrylate, methyl methacrylate, hydroxypropyl acrylate, methacrylic acid, and ammonium persulfate initiator of the other part dropwise. Mix evenly to obtain the core monomer emulsion. Mix the remaining water, emulsifier, acrylic acid, methacrylic acid, butyl acrylate, methyl methacrylate, hydroxyethyl acrylate, and ammonium persulfate initiator to obtain the shell monomer emulsion. Add the shell monomer emulsion to the core monomer emulsion and keep it at 75°C for 7 hours to obtain an acrylic core-shell emulsion with a solid content of 25%.

[0028] S2: Mix acrylic core-shell emulsion, N,N-dimethylethanolamine, and water, stir evenly, then add a portion of methylated amino resin, ethylene glycol butyl ether, dipropylene glycol butyl ether, anhydrous ethanol, additives, and pigments to obtain a baking-type waterborne single-component acrylic effect pigment coating.

[0029] Example 2 The difference between Example 2 and Example 1 is that the baking-type waterborne single-component acrylic effect pigment coating includes the following percentages of raw materials: 55% acrylic core-shell emulsion, 1% N,N-dimethylethanolamine, 1% partially methylated amino resin, 1% ethylene glycol butyl ether, 3% dipropylene glycol butyl ether, 10% anhydrous ethanol, 1% additives, 10% effect pigment, and the balance being water.

[0030] Example 3 The difference between Example 3 and Example 1 is that the baking-type waterborne single-component acrylic effect pigment coating includes the following percentages of raw materials: 65% acrylic core-shell emulsion, 2% N,N-dimethylethanolamine, 5% partially methylated amino resin, 5% ethylene glycol butyl ether, 1% dipropylene glycol butyl ether, 15% anhydrous ethanol, 4% additives, 6% effect pigment, and the balance being water.

[0031] Example 4 The difference between Example 4 and Example 1 is that the acrylic core-shell emulsion includes the following raw materials in parts by weight: 80 kg water, 10 kg butyl acrylate, 7 kg methyl methacrylate, 0.2 kg hydroxypropyl acrylate, 1 kg hydroxyethyl acrylate, 1 kg acrylic acid, 3 kg methacrylic acid, 0.1 kg ammonium persulfate initiator, and 0.5 kg reactive emulsifier.

[0032] Example 5 The difference between Example 5 and Example 1 is that the acrylic core-shell emulsion includes the following raw materials in parts by weight: 100 kg water, 7 kg butyl acrylate, 10 kg methyl methacrylate, 0.7 kg hydroxypropyl acrylate, 2 kg hydroxyethyl acrylate, 0.5 kg acrylic acid, 1 kg methacrylic acid, 0.3 kg ammonium persulfate initiator, and 1 kg reactive emulsifier.

[0033] Example 6 The difference between Example 6 and Example 1 is that the additive in the baking-type water-based single-component acrylic effect pigment coating raw material is dispersant BYK-192.

[0034] Example 7 The difference between Example 7 and Example 1 is that the effect pigment surface is double-coated with silica sol and additives.

[0035] A method for preparing a baking-type waterborne single-component acrylic effect pigment coating includes the following specific steps: S1: Divide each raw material of the acrylic core-shell emulsion into two equal parts. Heat the water and emulsifier of one part to 75°C, and then add butyl acrylate, methyl methacrylate, hydroxypropyl acrylate, methacrylic acid, and ammonium persulfate initiator of the other part dropwise. Mix evenly to obtain the core monomer emulsion. Mix the remaining water, emulsifier, acrylic acid, methacrylic acid, butyl acrylate, methyl methacrylate, hydroxyethyl acrylate, and ammonium persulfate initiator to obtain the shell monomer emulsion. Add the shell monomer emulsion to the core monomer emulsion and keep it at 75°C for 7 hours to obtain an acrylic core-shell emulsion with a solid content of 25%.

[0036] S2: Divide anhydrous ethanol into three equal parts. Mix tetraethyl orthosilicate, additives, and one part of anhydrous ethanol, and stir until homogeneous to form solution A. Then mix ammonia, water, and one part of anhydrous ethanol, and stir until homogeneous to form solution B. Mix the effect pigment with the remaining part of anhydrous ethanol to form a pigment solution. Stir until homogeneous under nitrogen protection. Heat the pigment solution to 55°C and then add solutions A and B dropwise. The mass ratio of tetraethyl orthosilicate, ammonia, water, effect pigment, and anhydrous ethanol is 2:3:2:50. Keep the reaction at this temperature for 5 hours. After filtration and drying, the double-coated effect pigment is obtained.

[0037] S3: Mix acrylic core-shell emulsion, N,N-dimethylethanolamine, and water, stir evenly, then add a portion of methylated amino resin, ethylene glycol butyl ether, dipropylene glycol butyl ether, anhydrous ethanol, additives, and double-coated effect pigments to obtain a baking-type waterborne single-component acrylic effect pigment coating.

[0038] Example 8 The difference between Example 8 and Example 7 is that the mass ratio of tetraethyl orthosilicate, ammonia, water, effect pigment and anhydrous ethanol in the double-coated effect pigment raw material is 3:5:2:80.

[0039] Comparative Example Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that an equal amount of fully methylated amino resin was used to replace part of the methylated amino resin in the baking-type waterborne single-component acrylic effect pigment coating raw material. The fully methylated amino resin was purchased from BASF-Luwipal066.

[0040] Performance testing According to the baking-type waterborne single-component acrylic effect pigment coatings provided in Examples 1-8 and Comparative Example 1 of this application, the coatings were applied with a mass ratio of coating to deionized water of 1:0.4 and baked at 105°C for 1 hour. The coatings were then subjected to the following performance tests, and the specific test results are shown in Table 1.

[0041] Detection methods I. Viscosity The viscosity of the coating prepared in this application was tested in accordance with the standard GB / T9269-2009 "Determination of viscosity of coatings".

[0042] II. Adhesion The adhesion effect of the coating prepared in this application was tested using the cross-cut test method in accordance with the standard GB / T9286-1998 "Cross-cut test of paint and varnish film".

[0043] III. Hardness The hardness of the coating prepared in this application was tested in accordance with the standard GB / T6739-2006 "Paints and Varnishes - Pencil Method for Testing Hardness of Coating Films".

[0044] IV. Water Resistance The water resistance of the coating prepared in this application was tested at 100℃ for 20 minutes, in accordance with the standard GB / T1733-1993 "Test Method for Water Resistance of Coating Film".

[0045] V. Gloss Referring to GB / T9754-2007 "Determination of 20°, 60° and 85° specular gloss of paint films without metallic pigments", the gloss of the coating prepared in this application at 60° was tested, and the appearance of the coating was observed.

[0046] Table 1: Performance Test Results Data Table The performance test results show that the baking-type waterborne single-component acrylic effect pigment coating prepared in this application can promote the directional alignment of effect pigments, prevent pigment displacement, and reduce pigment blooming and spotting on the coating surface. The partially methylated amino resin has higher reactivity than the fully methylated amino resin, enabling it to form a denser cross-linked structure with the acrylic core-shell emulsion, thereby enhancing the coating's hardness and stability and reducing pigment migration. A comparison between Comparative Example 1 and Example 1 shows that, using methylated amino resin in Comparative Example 1, the performance test results indicate that the stability of the effect pigments in the prepared coating is reduced, leading to a rougher surface.

[0047] A comparison of Example 6 and Example 1 shows that Example 6, using a conventional commercially available dispersant, resulted in a decrease in the overall performance of the coating, as indicated by performance testing. This further demonstrates that vinyltriethoxysiloxane can establish a bridge between the pigment and the polymer, promoting a tight bond between them, enhancing the compatibility between the pigment and the polymer, and improving the dispersibility and stability of the effect pigment in the coating system. Examples 7-8 demonstrate that double coating of the effect pigment with silica sol and additives resulted in a firm and uniform dispersion of the effect pigment in the coating system, improving the pigment orientation effect and resulting in a coating with better gloss and appearance.

[0048] 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 baking-type water-based one-component acrylic effect pigment coating, characterized in that, The raw materials include the following percentages: 55-65% acrylic core-shell emulsion, 1-2% N,N-dimethylethanolamine, 1-5% partially methylated amino resin, 1-5% ethylene glycol butyl ether, 1-3% dipropylene glycol butyl ether, 10-15% anhydrous ethanol, 1-4% additives, 6-10% effect pigments, and the balance being water.

2. The baking-type waterborne single-component acrylic effect pigment coating according to claim 1, characterized in that, The acrylic core-shell emulsion comprises the following raw materials in parts by weight: 80-100 parts water, 7-10 parts butyl acrylate, 7-10 parts methyl methacrylate, 0.2-0.7 parts hydroxypropyl acrylate, 1-2 parts hydroxyethyl acrylate, 0.5-1 parts acrylic acid, 1-3 parts methacrylic acid, 0.1-0.3 parts ammonium persulfate initiator, and 0.5-1 parts reactive emulsifier.

3. The baking-type waterborne single-component acrylic effect pigment coating according to claim 2, characterized in that, The preparation method of the acrylic core-shell emulsion includes the following specific steps: the raw materials of the acrylic core-shell emulsion are divided into two parts. One part is mixed with water and emulsifier and heated. Then, butyl acrylate, methyl methacrylate, hydroxypropyl acrylate, methacrylic acid, and ammonium persulfate initiator are added dropwise and mixed evenly to obtain a core monomer emulsion. The remaining part is mixed with water, emulsifier, acrylic acid, methacrylic acid, butyl acrylate, methyl methacrylate, hydroxyethyl acrylate, and ammonium persulfate initiator to obtain a shell monomer emulsion. The shell monomer emulsion is added to the core monomer emulsion and kept at a constant temperature to react, finally obtaining the acrylic core-shell emulsion.

4. The baking-type waterborne single-component acrylic effect pigment coating according to claim 3, characterized in that, The heating temperature is 60-90℃.

5. The baking-type waterborne single-component acrylic effect pigment coating according to claim 1, characterized in that, The effect pigment is one of pearlescent powder and aluminum powder, and the additive is vinyltriethoxysiloxane.

6. The baking-type waterborne single-component acrylic effect pigment coating according to claim 5, characterized in that, The surface of the effect pigment is coated with both silica sol and additives.

7. The baking-type waterborne single-component acrylic effect pigment coating according to claim 6, characterized in that, The method for double coating the surface of the effect pigment includes the following specific steps: Tetraethyl orthosilicate, additives, and anhydrous ethanol are mixed to form solution A. Then, ammonia, water, and anhydrous ethanol are mixed to form solution B. The effect pigment is mixed with anhydrous ethanol to form a pigment solution. The mixture is stirred evenly under nitrogen protection. After heating the pigment solution, solutions A and B are added dropwise. The reaction is maintained at this temperature. After filtration and drying, the double-coated effect pigment is obtained.

8. The baking-type waterborne single-component acrylic effect pigment coating according to claim 7, characterized in that, The mass ratio of the total mass of tetraethyl orthosilicate, ammonia, water, effect pigment and anhydrous ethanol is (2-3):(3-5):2:(50-80).

9. The baking-type waterborne single-component acrylic effect pigment coating according to claim 7, characterized in that, The heating temperature is 150-160℃.

10. A method for preparing a baking-type waterborne single-component acrylic effect pigment coating as described in any one of claims 1-9, characterized in that, The specific steps include the following: Acrylic core-shell emulsion, N,N-dimethylethanolamine, and water are mixed in advance and stirred evenly. Then, a portion of methylated amino resin, ethylene glycol butyl ether, dipropylene glycol butyl ether, anhydrous ethanol, additives, and effect pigments are added and mixed to obtain a baking-type waterborne one-component acrylic effect pigment coating.

Images