High-brightness and high-fineness water-based automobile silver powder paint, preparation method and application thereof

Abstract

The present application relates to a kind of high-brightness high-fine feeling water-based automobile silver powder paint and its preparation method and application.The water-based automobile silver powder paint provided by the present application includes, by weight percentage, acrylic modified polyurethane dispersion, silicone-polyurethane-acrylate ternary copolymer emulsion, amino resin, acetylenic diol surfactant, thickening agent, ultra-fine nano barium sulfate paste, silicon-coated aluminum silver paste, dispersant A, leveling agent, defoaming agent, N,N-dimethyl ethanolamine, ethylene glycol butyl ether, propylene glycol butyl ether, ethylene glycol iso-octyl ether and deionized water.The present application significantly improves the arrangement effect of water-based automobile silver powder paint silver powder, so that it has high stability, high brightness and high fineness at the same time, and can meet the basic performance of automobile original factory paint film.

Description

Technical Field

[0001] This invention belongs to the field of automotive coating technology, specifically relating to a high-brightness, high-fineness water-based automotive silver powder paint, its preparation method, and its application. Background Technology

[0002] Currently, the domestic and international automotive industry, especially the new energy vehicle industry, is developing at an unprecedentedly rapid pace. Correspondingly, the supporting automotive coatings industry is also experiencing unprecedented rapid growth. Generally speaking, automotive body coatings are mainly divided into solid color paints and metallic pigment paints (commonly known as silver powder paints). Metallic pigment paints, due to their content of metallic components such as aluminum powder (commonly known as silver powder), can exhibit a unique shimmering decorative effect, and therefore their proportion in automotive painting is increasing daily. Furthermore, in response to environmental protection requirements, more and more metallic pigment paints are gradually shifting from traditional solvent-based to water-based formulations.

[0003] The particle size of the silver powder plays a crucial role in the brightness and smoothness of the silver powder paint film. Typically, to give the paint film a smoother feel rather than a noticeable grainy texture, smaller silver powder particles are chosen. However, reducing the particle size of the silver powder weakens its light reflection, thus reducing the brightness of the paint film and affecting the display of the metallic texture. Therefore, to achieve a paint film with both high brightness and a smooth visual effect, the paint formulation needs to have excellent silver powder alignment capabilities, enhancing the directional arrangement of small and medium-sized silver powder particles in the paint film, thereby improving the directional reflection of light and ultimately achieving a dual improvement in high brightness and angle-dependent color variation.

[0004] Currently, water-based automotive metallic paints have the following main problems: Under existing technological conditions, the silver powder alignment effect of water-based metallic paints is generally poor, requiring the addition of directional alignment aids such as CAB, EVA wax, polyamide wax, and lithium magnesium silicate to improve it. For example, Chinese patent document CN103319965A discloses a water-based metallic paint for automobiles and its preparation method, which discloses the use of anti-settling agents such as ViscalexHV30 to improve the silver powder alignment effect; secondly, Chinese patent document CN111218183A discloses a method for preparing a high-whiteness metallic paint, which discloses the use of polyamide wax and EVA wax to improve the alignment of aluminum silver paste, thereby improving the brightness of the paint film. However, the current application conditions of some directional alignment aids are quite demanding, or the effect of improving alignment is only average, requiring a large amount; or the stability is poor, easily leading to problems such as gelation of the paint after use and large viscosity changes after storage, affecting the use and performance of the paint.

[0005] In summary, to address the shortcomings of existing water-based automotive silver powder paints, such as poor silver powder arrangement and difficulty in achieving both brightness and fineness, a water-based automotive silver powder paint with excellent arrangement and high brightness and fineness has been developed. This is of great significance for improving the overall performance of automotive body coatings and meeting the market demand for high-quality automotive coatings. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention aims to provide a high-brightness, high-fineness water-based automotive silver powder paint, its preparation method, and its application. This invention utilizes ultrafine nano-barium sulfate and organosilicon-polyurethane-acrylate ternary copolymer emulsion as novel directional alignment aids to improve the alignment effect of the water-based silver powder paint, enabling it to simultaneously possess high stability, high brightness, and high fineness, while meeting the basic performance requirements of original automotive paint films.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] The first objective of this invention is to provide a high-brightness, high-fineness water-based automotive silver powder paint, comprising the following raw materials by weight percentage:

[0009] The composition includes 12-18 parts of acrylic acid-modified polyurethane dispersion, 20-30 parts of silicone-polyurethane-acrylate terpolymer emulsion, 2-5 parts of amino resin, 0.5-1.5 parts of acetylenol surfactant, 0.5-2 parts of thickener, 2-5 parts of ultrafine nano barium sulfate paste, 4-6 parts of silica-coated aluminum silver paste, 0.1-1 parts of dispersant A, 0.05-0.5 parts of leveling agent, 0.1-1 parts of defoamer, 0.5-2 parts of N,N-dimethylethanolamine, 5-10 parts of ethylene glycol butyl ether, 1-5 parts of propylene glycol butyl ether, 1-5 parts of ethylene glycol isooctyl ether, and 20-40 parts of deionized water.

[0010] Preferably, the mass ratio of the acrylic acid-modified polyurethane dispersion to the silicone-polyurethane-acrylate terpolymer emulsion is 1:(1.3~2.8).

[0011] Preferably, the acrylic-modified polyurethane dispersion is at least one of DAOTAN TW6466 / 36WA, DAOTANTW6462 / 36WA, and DAOTAN TW6464 / 36WA; the silicone-polyurethane-acrylate terpolymer emulsion is Dolphin 1830; the amino resin is at least one of CYMEL 325 and CYMEL 327; the acetylenol surfactant is at least one of Evonik Surfynol 440, Surfynol 420, and Surfynol 104 DPM; and the thickener is at least one of BASF Viscalex HV 30 and RHEOVIS AS 1130.

[0012] Preferably, the ultrafine nano barium sulfate slurry comprises the following components by weight percentage: 30-50 parts of nano barium sulfate, 10-30 parts of dispersant B, and 20-40 parts of deionized water.

[0013] Preferably, the dispersant B is at least one of BYK-192 and BYK-190; and the nano-barium sulfate is at least one of Sakai Chemical's BARIFINE BF-20 and Hongzhi New Materials' FB-30.

[0014] Preferably, the preparation method of the ultrafine nano barium sulfate slurry includes:

[0015] (1) Add the formula amount of deionized water and dispersant B to the mixing tank in sequence. Disperse for 5 to 15 minutes at 300 to 600 rpm. Then add the formula amount of nano barium sulfate and disperse for more than 30 minutes at 500 to 700 rpm.

[0016] (2) Transfer all the liquid obtained in step (1) to a horizontal sand mill, add high-purity zirconia ceramic microspheres, the mass ratio of the high-purity zirconia ceramic microspheres to the liquid obtained in step (1) is (1~1.5):1, sand mill for 1.5~2.5h at 2500~3500 rpm, when the fineness of the liquid is <5μm, continue sand milling for more than 30min, and then discharge the material to obtain ultrafine nano barium sulfate slurry.

[0017] Preferably, the horizontal sand mill is a German Netzsch Instruments Manufacturing Co., Ltd. model LMZ-05C; the particle size of the high-purity zirconia ceramic microspheres is 0.3~0.6mm.

[0018] Preferably, the silica-coated aluminum silver paste is Anhui Xuyang 3016A water-based aluminum silver paste; the dispersant A is at least one of BYK-192 and BYK-190; the leveling agent is at least one of BYK-381, BYK-345 and BYK-347; and the defoamer is at least one of TEGO 810, TEGO Airex 902W and BYK-011.

[0019] Another object of the present invention is to provide a method for preparing the above-described high-brightness, high-fineness water-based automotive silver powder paint, comprising the following steps:

[0020] (1) Take the main cylinder A and add the formula amount of deionized water, N,N-dimethylethanolamine, acrylic acid modified polyurethane dispersion, organosilicon-polyurethane-acrylate terpolymer emulsion and amino resin in sequence. Disperse for 15-20 minutes at 300-600 rpm.

[0021] (2) Add the formulated amounts of propylene glycol butyl ether, acetylation glycol surfactant and defoamer to the main cylinder A in step (1) in sequence, and disperse for 5 to 15 minutes at 300 to 600 rpm;

[0022] (3) Add the formulated amount of ultrafine nano barium sulfate slurry to the main cylinder A in step (2), and disperse it for 5 to 15 minutes at 300 to 600 rpm;

[0023] (4) Take another auxiliary cylinder B, and add the prescribed amounts of silica-coated aluminum silver paste, ethylene glycol butyl ether and ethylene glycol isooctyl ether in sequence. After soaking for 1 to 3 hours, stir for 25 to 35 minutes to ensure that there are no lumps or agglomerates. Then, add the prescribed amounts of dispersant A and leveling agent in sequence, stir for 25 to 35 minutes to ensure that there are no lumps or agglomerates. While stirring, add the auxiliary cylinder B into the main cylinder A in step (3). Disperse for 15 to 20 minutes at 300 to 600 rpm.

[0024] (5) Add the formula amount of thickener to the main cylinder A in step (4), and disperse for 25 to 35 minutes at 500 to 800 rpm;

[0025] (6) While dispersing, adjust the pH using N,N-dimethylethanolamine to keep the pH value within the range of 8.0 to 9.0;

[0026] (7) After the pH value is adjusted, maintain at 300~600 rpm and disperse for 10~15 minutes to obtain high-brightness and high-fineness water-based automotive silver powder paint.

[0027] Another object of the present invention is to provide the application of the above-described high-brightness, high-fineness water-based automotive silver powder paint in the preparation of automotive coatings or in the field of automotive coating application.

[0028] The principles and concepts of this invention:

[0029] Based on the existing problems of water-based automotive silver powder paints, the silver powder alignment effect is usually poor, requiring the addition of directional alignment aids such as CAB, EVA wax, polyamide wax, and lithium magnesium silicate to improve it. However, the current directional alignment aids have harsh usage conditions, require large amounts, have only a general effect on improving alignment, and have poor stability. After use, they easily lead to problems such as gelation of the paint and large viscosity changes after storage, affecting the use and performance of the paint. The resulting water-based automotive silver powder paint cannot simultaneously achieve the effects of film brightness, smoothness, and stability. Based on this, this invention has researched and developed a high-brightness, high-smoothness water-based automotive silver powder paint. First, this invention selects two main resins with strong alkali swelling properties—acrylic-modified polyurethane dispersion and organosilicon-polyurethane-acrylate ternary copolymer emulsion—and limits their specific ratios. Through experiments, this invention found that when the amount of organosilicon-polyurethane-acrylate ternary copolymer emulsion is too large, the paint film becomes brittle, resulting in poor mechanical properties such as impact resistance; while when the amount of acrylic-modified polyurethane dispersion is too large, on the one hand, the formulation cost increases, and on the other hand, the silver powder directional alignment effect decreases. This invention demonstrates that only under the specific ratio conditions of the two main resins can the paint film achieve a good silver powder arrangement effect while ensuring the requirements for impact resistance and water resistance. Secondly, the organosilicon-polyurethane-acrylate ternary copolymer emulsion used in this invention is a ternary copolymer compound that not only possesses the functions of ordinary acrylic emulsions but also the functions of organosilicon and polyurethane. The modified organosilicon provides better leveling of the paint film, while the modified polyurethane offers better paint film performance.

[0030] Furthermore, this invention utilizes the high dispersibility of nano-barium sulfate for sheet-like pigments and fillers to enhance the directional alignment of silver powder. Its mechanism of action is as follows: Figure 1 As shown. Because barium sulfate is an inert substance, compared with other traditional alignment aids (such as EVA wax, lithium magnesium silicate, etc.), barium sulfate has almost no post-reaction in the coating system and has extremely high stability, avoiding problems such as coating gelation and post-thickening caused by the instability of alignment aids.

[0031] This invention uses self-made nano-barium sulfate slurry and organosilicon-polyurethane-acrylate ternary copolymer emulsion to improve the alignment effect of water-based silver powder paint, eliminating the need for additional silver powder alignment additives such as polyamide wax, EVA wax, and lithium magnesium silicate. It also improves the storage stability of the paint liquid, enabling the paint film to have excellent silver powder alignment and shimmering effect, giving it high stability, high brightness, and high fineness, while meeting the basic performance requirements of automotive original paint films.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] This invention provides a high-brightness, high-fineness water-based automotive silver powder paint that enables the paint film to simultaneously possess high stability, high brightness, and high fineness, meeting the basic performance requirements of original automotive paint films.

[0034] Meanwhile, the preparation method of high-brightness and high-fineness water-based automotive silver powder paint provided by the present invention, compared with the prior art, does not require the addition of other silver powder arrangement aids such as polyamide wax, EVA wax, and lithium magnesium silicate, which simplifies the production process, reduces production costs, and is suitable for large-scale production.

[0035] Applying the high-brightness, high-fineness water-based automotive silver powder paint provided by this invention to the preparation of automotive coatings or in the field of automotive coating application can significantly improve the application performance and coating effect of the coating. Attached Figure Description

[0036] Figure 1 This invention relates to the mechanism by which ultrafine nano barium sulfate paste enhances the arrangement of silver powder.

[0037] Figure 2 The measurement principle of the BYK mac i multi-angle colorimeter;

[0038] Figure 3 This is a graph showing the relationship between G-value and paint film fineness.

[0039] Figure 4 This is the effect of a 100x microscope as shown in Example 1;

[0040] Figure 5 This is a 100x microscope image of Comparative Example 1.

[0041] Figure 6 This is a 100x microscope image of Comparative Example 2;

[0042] Figure 7 This is a 100x microscope image of Comparative Example 3;

[0043] Figure 8 This is a 100x microscope image of Comparative Example 4;

[0044] Figure 9 This is a 100x microscope image of Comparative Example 5;

[0045] Figure 10 This is a 100x microscope effect for Comparative Example 6. Detailed Implementation

[0046] The following detailed embodiments further illustrate the above-described content of the present invention. However, this should not be construed as limiting the scope of the present invention to the following embodiments.

[0047] 1. Raw materials

[0048] Table 1 Sources of raw materials for the formula

[0049]

[0050] 2. Equipment and Instruments

[0051] The multi-angle colorimeter was purchased from BYK GmbH, Germany, and its model is BYK mac i.

[0052] The horizontal sand mill was purchased from NETZSCH Geratebau GmbH, Germany, model LMZ-05C.

[0053] Example 1: High-brightness, high-fineness water-based automotive silver powder paint of the present invention and its preparation.

[0054] The preparation of the ultrafine nano barium sulfate slurry of the present invention includes the components shown in the table below:

[0055] Table 2. Composition of ultrafine nano barium sulfate slurry

[0056]

[0057] The present invention discloses a method for preparing ultrafine nano-barium sulfate slurry, comprising:

[0058] (1) Add the formula amount of deionized water and dispersant B to the mixing tank in sequence. Disperse for 10 minutes at 400 rpm. Then add the formula amount of nano barium sulfate and disperse for more than 30 minutes at 600 rpm.

[0059] (2) Transfer all the liquid material obtained in step (1) to a horizontal sand mill, add high-purity zirconia ceramic microspheres, the mass ratio of the high-purity zirconia ceramic microspheres to the liquid material obtained in step (1) is 1.2:1, sand mill at 3000 rpm for 2 hours, when the fineness of the liquid material is detected to be <5μm, continue sand milling for more than 30 minutes, and then discharge the material to obtain ultrafine nano barium sulfate slurry. The horizontal sand mill is a German Netzsch LMZ-05C; the particle size of the high-purity zirconia ceramic microspheres is 0.3mm.

[0060] The preparation of the high-brightness, high-fineness water-based automotive silver powder paint of the present invention includes the raw materials shown in the table below:

[0061] Table 3 Raw materials for the high-brightness, high-fineness water-based automotive silver powder paint of this invention

[0062]

[0063] The present invention discloses a method for preparing a high-brightness, high-fineness water-based automotive silver powder paint, comprising the following steps:

[0064] (1) Take the main cylinder A and add the formula amount of deionized water, N,N-dimethylethanolamine, acrylic acid modified polyurethane dispersion, organosilicon-polyurethane-acrylate terpolymer emulsion and amino resin in sequence. Disperse for 15 minutes at 400 rpm.

[0065] (2) Add the formulated amounts of propylene glycol butyl ether, acetylsalicylic acid diol surfactant and defoamer to the main cylinder A in step (1) in sequence, and disperse for 10 minutes at 500 rpm;

[0066] (3) Add the formulated amount of ultrafine nano barium sulfate slurry to the main cylinder A in step (2) and disperse it for 10 minutes at 500 rpm;

[0067] (4) Take another auxiliary cylinder B, and add the prescribed amounts of silica-coated aluminum silver paste, ethylene glycol butyl ether and ethylene glycol isooctyl ether in sequence. After soaking for 2 hours, stir for 30 minutes to ensure that there are no lumps or agglomerates. Then, add the prescribed amounts of dispersant A and leveling agent in sequence, stir for 30 minutes to ensure that there are no lumps or agglomerates. While stirring, add the auxiliary cylinder B into the main cylinder A of step (3) and disperse for 15 minutes at 500 rpm.

[0068] (5) Add the amount of thickener specified in the formula to the main cylinder A in step (4), and disperse for 30 minutes at 600 rpm;

[0069] (6) While dispersing, adjust the pH using N,N-dimethylethanolamine to keep the pH value within the range of 8.0 to 9.0;

[0070] (7) After the pH value is adjusted, keep it at 500 rpm and disperse for 10 minutes to obtain high-brightness and high-fineness water-based automotive silver powder paint.

[0071] Example 2: High-brightness, high-fineness water-based automotive silver powder paint of the present invention and its preparation.

[0072] The preparation of the ultrafine nano barium sulfate slurry of the present invention includes the components shown in the table below:

[0073] Table 4. Composition of ultrafine nano barium sulfate slurry

[0074]

[0075] The present invention discloses a method for preparing ultrafine nano-barium sulfate slurry, comprising:

[0076] (1) Add the formula amount of deionized water and dispersant B to the mixing tank in sequence. Disperse for 15 minutes at 300 rpm. Then add the formula amount of nano barium sulfate and disperse for more than 30 minutes at 500 rpm.

[0077] (2) Transfer all the liquid material obtained in step (1) to a horizontal sand mill, add high-purity zirconia ceramic microspheres, the mass ratio of the high-purity zirconia ceramic microspheres to the liquid material obtained in step (1) is 1:1, and sand mill at 3000 rpm for 2.5 h. When the fineness of the liquid material is detected to be <5μm, continue sand milling for more than 30 min, and then discharge the material to obtain ultrafine nano barium sulfate slurry. The horizontal sand mill is a German Netzsch LMZ-05C; the particle size of the high-purity zirconia ceramic microspheres is 0.4 mm.

[0078] The preparation of the high-brightness, high-fineness water-based automotive silver powder paint of the present invention includes the raw materials shown in the table below:

[0079] Table 5. Raw materials for the high-brightness, high-fineness water-based automotive silver powder paint of this invention.

[0080]

[0081] The present invention discloses a method for preparing a high-brightness, high-fineness water-based automotive silver powder paint, comprising the following steps:

[0082] (1) Take the main cylinder A and add the formula amount of deionized water, N,N-dimethylethanolamine, acrylic acid modified polyurethane dispersion, organosilicon-polyurethane-acrylate terpolymer emulsion and amino resin in sequence. Disperse for 20 minutes at 300 rpm.

[0083] (2) Add the formulated amounts of propylene glycol butyl ether, acetylsalicylic acid diol surfactant and defoamer to the main cylinder A in step (1) in sequence, and disperse for 15 minutes at 300 rpm;

[0084] (3) Add the formulated amount of ultrafine nano barium sulfate slurry to the main cylinder A in step (2) and disperse it for 15 minutes at 300 rpm;

[0085] (4) Take another auxiliary cylinder B, and add the prescribed amounts of silica-coated aluminum silver paste, ethylene glycol butyl ether and ethylene glycol isooctyl ether in sequence. After soaking for 1 hour, stir for 35 minutes to ensure that there are no lumps or agglomerates. Then, add the prescribed amounts of dispersant A and leveling agent in sequence, stir for 35 minutes to ensure that there are no lumps or agglomerates. While stirring, add the auxiliary cylinder B into the main cylinder A of step (3) and disperse for 20 minutes at 300 rpm.

[0086] (5) Add the amount of thickener specified in the formula to the main cylinder A in step (4), and disperse for 35 minutes at 500 rpm;

[0087] (6) While dispersing, adjust the pH using N,N-dimethylethanolamine to keep the pH value within the range of 8.0 to 9.0;

[0088] (7) After the pH value is adjusted, keep the speed at 300 rpm and disperse for 15 minutes to obtain high-brightness, high-fineness water-based automotive silver powder paint.

[0089] Example 3: High-brightness, high-fineness water-based automotive silver powder paint of the present invention and its preparation.

[0090] The preparation of the ultrafine nano barium sulfate slurry of the present invention includes the components shown in the table below:

[0091] Table 6. Composition of ultrafine nano barium sulfate slurry

[0092]

[0093] The present invention discloses a method for preparing ultrafine nano-barium sulfate slurry, comprising:

[0094] (1) Add the formula amount of deionized water and dispersant B to the mixing tank in sequence. Disperse for 5 minutes at 600 rpm. Then add the formula amount of nano barium sulfate and disperse for more than 30 minutes at 700 rpm.

[0095] (2) Transfer all the liquid material obtained in step (1) to a horizontal sand mill, add high-purity zirconia ceramic microspheres, the mass ratio of the high-purity zirconia ceramic microspheres to the liquid material obtained in step (1) is 1.5:1, and sand mill for 1.5 hours at 3000 rpm. When the fineness of the liquid material is detected to be <5μm, continue sand milling for more than 30 minutes, and then discharge the material to obtain ultrafine nano barium sulfate slurry. The horizontal sand mill is a German Netzsch LMZ-05C; the particle size of the high-purity zirconia ceramic microspheres is 0.5mm.

[0096] The preparation of the high-brightness, high-fineness water-based automotive silver powder paint of the present invention includes the raw materials shown in the table below:

[0097] Table 7 Raw materials for the high-brightness, high-fineness water-based automotive silver powder paint of this invention

[0098]

[0099] The present invention discloses a method for preparing a high-brightness, high-fineness water-based automotive silver powder paint, comprising the following steps:

[0100] (1) Take the main cylinder A and add the formula amount of deionized water, N,N-dimethylethanolamine, acrylic acid modified polyurethane dispersion, organosilicon-polyurethane-acrylate terpolymer emulsion and amino resin in sequence. Disperse for 15 minutes at 600 rpm.

[0101] (2) Add the formulated amounts of propylene glycol butyl ether, acetylsalicylic acid diol surfactant and defoamer to the main cylinder A in step (1) in sequence, and disperse for 5 minutes at 600 rpm;

[0102] (3) Add the formulated amount of ultrafine nano barium sulfate slurry to the main cylinder A in step (2) and disperse it for 5 minutes at 600 rpm;

[0103] (4) Take another auxiliary cylinder B, and add the prescribed amounts of silica-coated aluminum silver paste, ethylene glycol butyl ether and ethylene glycol isooctyl ether in sequence. After soaking for 3 hours, stir for 25 minutes to ensure that there are no lumps or agglomerates. Then, add the prescribed amounts of dispersant A and leveling agent in sequence, stir for 25 minutes to ensure that there are no lumps or agglomerates. While stirring, add the auxiliary cylinder B into the main cylinder A of step (3) and disperse for 15 minutes at 600 rpm.

[0104] (5) Add the amount of thickener specified in the formula to the main cylinder A in step (4), and disperse for 25 minutes at 800 rpm;

[0105] (6) While dispersing, adjust the pH using N,N-dimethylethanolamine to keep the pH value within the range of 8.0 to 9.0;

[0106] (7) After the pH value is adjusted, keep it at 600 rpm and disperse for 10 minutes to obtain high-brightness and high-fineness water-based automotive silver powder paint.

[0107] Example 4: High-brightness, high-fineness water-based automotive silver powder paint of the present invention and its preparation.

[0108] The preparation of the ultrafine nano barium sulfate slurry of the present invention includes the components shown in the table below:

[0109] Table 8. Composition of ultrafine nano barium sulfate slurry

[0110]

[0111] The present invention discloses a method for preparing ultrafine nano-barium sulfate slurry, comprising:

[0112] (1) Add the formula amount of deionized water and dispersant B to the mixing tank in sequence. Disperse for 10 minutes at 500 rpm. Then add the formula amount of nano barium sulfate and disperse for more than 30 minutes at 600 rpm.

[0113] (2) Transfer all the liquid material obtained in step (1) to a horizontal sand mill, add high-purity zirconia ceramic microspheres, the mass ratio of the high-purity zirconia ceramic microspheres to the liquid material obtained in step (1) is 1.3:1, sand mill at 3000 rpm for 2 hours, when the fineness of the liquid material is detected to be <5μm, continue sand milling for more than 30 minutes, and then discharge the material to obtain ultrafine nano barium sulfate slurry. The horizontal sand mill is a German Netzsch LMZ-05C; the particle size of the high-purity zirconia ceramic microspheres is 0.6mm.

[0114] The preparation of the high-brightness, high-fineness water-based automotive silver powder paint of the present invention includes the raw materials shown in the table below:

[0115] Table 9 Raw materials for the high-brightness, high-fineness water-based automotive silver powder paint of this invention

[0116]

[0117] The present invention discloses a method for preparing a high-brightness, high-fineness water-based automotive silver powder paint, comprising the following steps:

[0118] (1) Take the main cylinder A and add the formula amount of deionized water, N,N-dimethylethanolamine, acrylic acid modified polyurethane dispersion, organosilicon-polyurethane-acrylate terpolymer emulsion and amino resin in sequence. Disperse for 20 minutes at 400 rpm.

[0119] (2) Add the formulated amounts of propylene glycol butyl ether, acetylsalicylic acid diol surfactant and defoamer to the main cylinder A in step (1) in sequence, and disperse for 10 minutes at 500 rpm;

[0120] (3) Add the formulated amount of ultrafine nano barium sulfate slurry to the main cylinder A in step (2) and disperse it for 10 minutes at 500 rpm;

[0121] (4) Take another auxiliary cylinder B, and add the prescribed amounts of silica-coated aluminum silver paste, ethylene glycol butyl ether and ethylene glycol isooctyl ether in sequence. After soaking for 2 hours, stir for 30 minutes to ensure that there are no lumps or agglomerates. Then, add the prescribed amounts of dispersant A and leveling agent in sequence, stir for 30 minutes to ensure that there are no lumps or agglomerates. While stirring, add the auxiliary cylinder B into the main cylinder A of step (3) and disperse for 20 minutes at 500 rpm.

[0122] (5) Add the amount of thickener specified in the formula to the main cylinder A in step (4), and disperse for 30 minutes at 700 rpm;

[0123] (6) While dispersing, adjust the pH using N,N-dimethylethanolamine to keep the pH value within the range of 8.0 to 9.0;

[0124] (7) After the pH value is adjusted, keep it at 500 rpm and disperse for 10 minutes to obtain high-brightness and high-fineness water-based automotive silver powder paint.

[0125] Comparative Example 1

[0126] Compared with Example 1, the amount of acrylic acid modified polyurethane dispersion added in this example is 8 parts, the amount of silicone-polyurethane-acrylate terpolymer emulsion added is 31 parts, and the rest is the same as in Example 1.

[0127] Water-based automotive silver powder paint was prepared using the preparation method described in Example 1.

[0128] Comparative Example 2

[0129] Compared with Example 1, the amount of acrylic acid modified polyurethane dispersion added in this example is 20 parts, the amount of silicone-polyurethane-acrylate terpolymer emulsion added is 19 parts, and the rest is the same as in Example 1.

[0130] Water-based automotive silver powder paint was prepared using the preparation method described in Example 1.

[0131] Comparative Example 3

[0132] Compared with Example 1, this example replaces the ultrafine nano barium sulfate slurry with the EVA wax-type silver powder directional additive BYK AQUACER 526, and the rest is the same as in Example 1.

[0133] Water-based automotive silver powder paint was prepared using the preparation method described in Example 1.

[0134] Comparative Example 4

[0135] Compared with Example 1, this example replaces the ultrafine nano barium sulfate slurry with polyamide wax silver powder directional additive DISPARON AQH-810, and the rest is the same as in Example 1.

[0136] Water-based automotive silver powder paint was prepared using the preparation method described in Example 1.

[0137] Comparative Example 5

[0138] Compared with Example 1, in the preparation method of the high-brightness and high-fineness water-based automotive silver powder paint in this example, step (6) uses N,N-dimethylethanolamine to adjust the pH to 7.5, and the rest is the same as in Example 1.

[0139] Comparative Example 6

[0140] Compared with Example 1, in the preparation method of the high-brightness and high-fineness water-based automotive silver powder paint in this example, step (6) uses N,N-dimethylethanolamine to adjust the pH to 9.5, and the rest is the same as in Example 1.

[0141] Experiment 1

[0142] The water-based automotive silver powder paints prepared in Examples 1-4 and Comparative Examples 1-6 of this invention were subjected to performance tests. The test methods and test results are shown in Tables 10, 11, 12 and 13.

[0143] (1) Testing items and testing methods

[0144] Table 10

[0145]

[0146] The names of the standards involved are as follows:

[0147] GB / T 9754 "Determination of 20°, 60° and 85° specular gloss of paint films without metallic pigments";

[0148] GB / T 9286 "Paints and Varnishes Cross-cut Test";

[0149] GB / T 6739 "Determination of Hardness of Paints and Varnishes by Pencil Method";

[0150] GB / T 1732 "Determination of Impact Resistance of Coatings";

[0151] GB / T 9753 Cupping Test for Paints and Varnishes;

[0152] GB / T 1733 "Determination of Water Resistance of Coating Films";

[0153] GB / T 9274 "Determination of resistance to liquid media in paints and varnishes";

[0154] GB / T 1740 "Determination of Damp Heat Resistance of Coatings";

[0155] GB / T 6753.3 "Test Method for Storage Stability of Coatings";

[0156] GB / T 1865 Paints and varnishes - Artificial weathering and artificial radiation exposure - Filtered xenon arc radiation.

[0157] Test Item Description:

[0158] The brightness, silver powder arrangement, and fineness of the paint film can typically be evaluated digitally using a BYKmac i multi-angle colorimeter, in addition to direct visual assessment.

[0159] L-value: Reflects the brightness of the paint film. BYK mac i can directly measure the L-value at different viewing angles (15°, 25°, 45°, 75°, and 110°). The measurement principle is as follows: Figure 2 As shown, the larger the L value, the brighter the paint film.

[0160] FI value: Reflects the angular heterochromaticity of lightness (L value), and its specific calculation formula is as follows:

[0161] FI = 2.69 × (L) 15° -L 110° ) 1.11 / L 45° 0.86

[0162] The FI value indicates the change in brightness of the paint film when observed from different angles. Generally, well-aligned metallic silver flakes in a paint film produce strong specular reflection when parallel light shines on it, resulting in high brightness at small angles (15°, 25°) and low brightness at large angles (45°, 75°, 110°), leading to a higher FI value. Conversely, if the metallic alignment of the paint film is poor, the silver flakes "stand up" rather than "lay out," resulting in strong light scattering, lower brightness at small angles, and higher brightness at large angles, causing a lower FI value. Therefore, the FI value is an important criterion for judging the quality of the oriented alignment of the aluminum silver flakes in a paint film.

[0163] G-value: Reflects the grainy texture of the paint film, indicating whether it is rough or smooth. Generally, a very uniform solid color paint has a G-value of 0. The smaller the G-value, the more pronounced the smoothness of the paint film. (See diagram below for the relationship between G-value and paint film smoothness.) Figure 3 As shown.

[0164] Pursuing only high fineness and using aluminum silver paste with medium or fine particle size can easily reduce the G value, but at the same time, the brightness L value of the paint film will be lower, resulting in a poorer visual metallic effect. Therefore, the paint formulation needs to have good silver powder orientation and arrangement to enhance the "flatness" of the silver powder flakes, so that the paint film can have both high fineness and high brightness.

[0165] (2) Test results

[0166] Table 11 Test results of high-brightness, high-fineness water-based automotive silver powder paints in Examples 1-4 of the present invention

[0167]

[0168] Table 12 Test results of water-based automotive silver paints in Comparative Examples 1-6

[0169]

[0170] Table 13 Measurement Results of BYK-mac i Multi-Angle Colorimeter

[0171]

[0172] (3) Analysis of experimental results

[0173] Compared with Example 1, Comparative Examples 1 and 2 adjusted the mass ratio of acrylic-modified polyurethane dispersion and silicone-polyurethane-acrylate terpolymer emulsion; Comparative Examples 3 and 4 replaced ultrafine nano-barium sulfate slurry with commercially available silver powder directional additives; and Comparative Examples 5 and 6 adjusted the reaction pH. Combined with experimental results such as paint performance testing and colorimeter data, it can be concluded that:

[0174] The change in the mass ratio of acrylic-modified polyurethane dispersion and organosilicon-polyurethane-acrylate terpolymer emulsion affects the FI value, G value, water resistance, cupping test, and impact resistance of automotive paint films, causing them to fail to meet automotive paint film performance requirements. Using commercially available silver powder orientation additives has little impact on paint film properties such as water resistance, but the L value and FI value are lower, indicating that its silver powder arrangement effect is slightly worse than the ultrafine nano-barium sulfate paste of this invention. Furthermore, after storage at 40℃ for 30 days, the paint oil moderately thickens, indicating even worse storage stability. Adjusting the pH value to ≤7.5 results in incomplete resin swelling and a decrease in paint film brightness; adjusting the pH value to ≥9.5 results in excessive resin swelling, worse storage stability, and a significant decrease in viscosity, indicating that a pH value in the range of 8.0~9.0 is more suitable.

[0175] Experiment 2

[0176] To further observe the arrangement effect of the water-based automotive silver powder paint of the present invention, the water-based automotive silver powder paints prepared in Example 1 and Comparative Examples 1-6 were observed under a 100x microscope. The microscope was purchased from Leica GmbH, Germany, model DM2700M.

[0177] Experimental results as follows Figures 4-10 As shown in the experimental results, the water-based automotive silver powder paint prepared in Example 1 of this invention has a tightly packed silver powder and a very small blackening area. The directional arrangement effect of the silver powder is significantly better than that of comparative examples 2 to 5.

[0178] In summary, this invention combines an acrylic-modified polyurethane dispersion with a silicone-polyurethane-acrylate terpolymer emulsion, and adds nano-barium sulfate paste to assist in the directional arrangement of silver powder. This achieves a high FI value (FI > 15), a high L value (L15° > 140), and a low G value (G < 4.5). Furthermore, the paint showed no abnormalities after 30 days of storage at 40°C, and the paint film performance remained normal, indicating that this invention simultaneously meets the requirements of high gloss, high fineness, and high stability. The appropriate ratio of the acrylic-modified polyurethane dispersion to the silicone-polyurethane-acrylate terpolymer emulsion ensures excellent paint film performance, such as water resistance and damp heat resistance for over 10 days, a cross-cut adhesion grade of 0, and no obvious discoloration or other paint film abnormalities. The paint film exhibits good flexibility, and its impact resistance and cupping resistance test results exceed the requirements of most automotive original equipment manufacturer (OEM) paints.

[0179] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A high-brightness high-fineness water-based automotive silver powder paint, characterized by, The high-brightness and high-fine-feeling water-based automobile silver powder paint comprises the following raw materials in percentage by weight: acrylic modified polyurethane dispersion 12~18 parts, silicone-polyurethane-acrylate terpolymer emulsion 20~30 parts, amino resin 2~5 parts, acetylenic diol surfactant 0.5~1.5 parts, thickening agent 0.5~2 parts, superfine nano barium sulfate slurry 2~5 parts, silica-coated aluminum silver slurry 4~6 parts, dispersant A 0.1~1 parts, leveling agent 0.05~0.5 parts, defoaming agent 0.1~1 parts, N,N-dimethyl ethanolamine 0.5~2 parts, ethylene glycol butyl ether 5~10 parts, propylene glycol butyl ether 1~5 parts, ethylene glycol iso-octyl ether 1~5 parts and deionized water 20~40 parts; The pH value of the high-brightness and high-fine-feeling water-based automobile silver powder paint is in the range of 8.0~9.

0.

2. The high-brightness high-fineness water-based automotive silver powder paint according to claim 1, characterized by, The mass ratio of the acrylic modified polyurethane dispersion and the silicone-polyurethane-acrylate terpolymer emulsion is 1: (1.3~2.8).

3. The high-brightness high-fineness water-based automotive silver powder paint according to claim 1, characterized by, The acrylic modified polyurethane dispersion is at least one of Zhanxin DAOTAN TW6466 / 36WA, DAOTAN TW6462 / 36WA and DAOTAN TW6464 / 36WA; the silicone-polyurethane-acrylate terpolymer emulsion is Dolphin 1830 of Dolphin New Materials; the amino resin is at least one of CYMEL 325 and CYMEL 327 of Zhanxin; the acetylenic diol surfactant is at least one of Surfynol 440, Surfynol 420 and Surfynol 104 DPM of Wincell; and the thickening agent is at least one of Viscalex HV 30 and RHEOVIS AS 1130 of BASF.

4. The high-brightness high-fineness water-based automotive silver powder paint according to claim 1, characterized by, The superfine nano barium sulfate slurry comprises the following components in percentage by weight: nano barium sulfate 30~50 parts, dispersant B 10~30 parts and deionized water 20~40 parts.

5. The high-brightness high-fineness water-based automotive silver powder paint according to claim 4, characterized by, The dispersant B is at least one of BYK-192 and BYK-190 of BYK; and the nano barium sulfate is at least one of BARIFINE BF-20 of Sakai Chemical and FB-30 of Hongzhi New Materials.

6. The high-brightness high-fineness water-based automotive silver powder paint according to claim 5, characterized by, The preparation method of the superfine nano barium sulfate slurry comprises: (1) sequentially adding the formula amount of deionized water and dispersant B into a stirring cylinder, and dispersing for 5~15 minutes under the condition of 300~600 revolutions per minute, then adding the formula amount of nano barium sulfate, and dispersing for 30 minutes or more under the condition of 500~700 revolutions per minute; (2) transferring all the liquid obtained in step (1) to a horizontal sand mill, adding high-purity zirconia ceramic microbeads, the mass ratio of the high-purity zirconia ceramic microbeads to the liquid obtained in step (1) being (1~1.5):1, sand milling for 1.5~2.5 hours under the condition of 2500~3500 revolutions per minute, continuing to sand mill for 30 minutes or more when the fineness of the liquid is less than 5 microns, and then discharging, to obtain the superfine nano barium sulfate slurry.

7. The high-brightness high-fineness water-based automotive silver powder paint according to claim 6, characterized by, The horizontal sand mill is LMZ-05C of Nanjing Laizhi Instrument Manufacturing Co., Ltd.; and the particle size of the high-purity zirconia ceramic microbeads is 0.3~0.6 mm.

8. The high-brightness high-fineness water-based automotive silver powder paint according to claim 1, characterized by, The silica-coated aluminum silver paste is Anhui Xiyang 3016A water-based aluminum silver paste; the dispersant A is at least one of BYK-192 and BYK-190; the leveling agent is at least one of BYK-381, BYK-345 and BYK-347; and the defoaming agent is at least one of TEGO 810, Airex 902W and BYK-011.

9. The method of claim 1 to 8, wherein the high-brightness and high-fineness water-based automotive silver powder paint is prepared by adding 0.1 to 1.0 parts by weight of a dispersant to 100 parts by weight of a silver powder, and then adding 0.1 to 1.0 parts by weight of a surfactant to the mixture. The method comprises the following steps: (1) Take the main cylinder A, and sequentially add the formula amount of deionized water, N, N dimethyl ethanolamine, acrylic modified polyurethane dispersion, silicone-polyurethane-acrylate ternary copolymer emulsion and amino resin, and disperse for 15-20 minutes under the condition of 300-600 rpm; (2) To the main cylinder A in step (1), sequentially add the formula amount of propylene glycol butyl ether, acetylene glycol surfactant and defoaming agent, and disperse for 5-15 minutes under the condition of 300-600 rpm; (3) To the main cylinder A in step (2), add the formula amount of superfine nano barium sulfate paste, and disperse for 5-15 minutes under the condition of 300-600 rpm; (4) Take another auxiliary cylinder B, and sequentially add the formula amount of silica-coated aluminum silver paste, ethylene glycol butyl ether and ethylene glycol isooctyl ether, soak for 1-3 hours, then stir for 25-35 minutes, ensure that there is no lump and no agglomeration, then sequentially add the formula amount of dispersant A and leveling agent, stir for 25-35 minutes, ensure that there is no lump and no agglomeration, then add the auxiliary cylinder B into the main cylinder A in step (3) while stirring, and disperse for 15-20 minutes under the condition of 300-600 rpm; (5) To the main cylinder A in step (4), add the formula amount of thickening agent, and disperse for 25-35 minutes under the condition of 500-800 rpm; (6) Adjust the pH value by using N, N dimethyl ethanolamine while dispersing, so that the pH value is in the range of 8.0-9.0; (7) After the pH value is adjusted, keep the speed at 300-600 rpm and disperse for 10-15 minutes, and then the high-brightness high-fineness water-based automobile silver paste is obtained.

10. The application of the high-brightness high-fineness water-based automobile silver paste according to any one of claims 1-8 or the preparation method of claim 9 in the preparation of automobile coatings or in the field of automobile coating painting.

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