Water-based transparent finish paint with high stain resistance and preparation method thereof

Abstract

The invention discloses water-based transparent finish paint with high stain resistance and a preparation method thereof. The finish paint is prepared from the following components in parts by weight: 70 to 85 parts of composite water-based resin, 0.05 to 0.15 part of a pH regulator, 0.4 to 0.8 part of a de-foaming agent, 0.3 to 0.7 part of a wetting agent, 4 to 6 parts of a coalescing agent, 3 to 5 parts of super-hydrophobic filler, 0.2 to 0.4 part of a flatting agent, 0.4 to 0.8 part of a thickening agent and 5 to 10 parts of water, the composite water-based resin is a compound composed of a modified water-based polyurethane dispersion and organic fluorine modified water-based acrylic resin according to the weight ratio of 1: (0.5-1), and the mass ratio of the composite water-based resin to the super-hydrophobic filler is (15-25): 1. Through the cooperation of specific resin compounding and the filler, a paint film has excellent stain resistance, water resistance, high transparency and good adhesive force, meanwhile, the environmental protection property is good, the preparation process is simple, and the paint is suitable for industrial production.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a water-based, highly stain-resistant transparent topcoat and its preparation method. Background Technology

[0002] With increasingly stringent environmental regulations and growing consumer awareness of environmental protection, water-based coatings are gaining widespread application due to their low volatile organic compound (VOC) content. As the final coating on woodwork, furniture, and other surfaces, clear topcoat not only requires excellent decorative properties and transparency but also demands higher performance in terms of stain resistance, water resistance, hardness, and adhesion.

[0003] Traditional water-based acrylic topcoats, while environmentally friendly, suffer from drawbacks such as low film hardness, mediocre heat and stain resistance, and poor fullness. While single-component water-based polyurethane (PUA) topcoats offer improved hardness and abrasion resistance, they still fall short in stain resistance and cost control. Furthermore, to enhance the hydrophobicity and stain resistance of the film surface, inorganic fillers such as silica are often added, but this often leads to decreased film transparency, reduced water resistance, and even affects the overall performance of the film. Chinese invention patent application CN202510766884.X discloses an abrasion-resistant water-based polyurethane topcoat and its preparation method. This coating exhibits good corrosion resistance, adhesion, and low-temperature curing characteristics, but still falls short in stain resistance.

[0004] Therefore, developing an environmentally friendly water-based topcoat that combines excellent stain resistance, water resistance, high hardness, and good transparency has significant market value and application prospects. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention provides a water-based, highly stain-resistant transparent topcoat and its preparation method. This topcoat achieves a balance of environmental friendliness, high stain resistance, excellent water resistance, and good film hardness through the synergistic effect of specific resin formulations and fillers.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A water-based, highly stain-resistant, transparent topcoat comprises the following components in parts by weight: 70-85 parts of composite water-based resin, 0.05-0.15 parts of pH adjuster, 0.4-0.8 parts of defoamer, 0.3-0.7 parts of wetting agent, 4-6 parts of film-forming aid, 3-5 parts of superhydrophobic filler, 0.2-0.4 parts of leveling agent, 0.4-0.8 parts of thickener, and 5-10 parts of water; The composite waterborne resin is a combination of a modified waterborne polyurethane dispersion and an organofluorine modified waterborne acrylic resin.

[0007] Furthermore, the modified waterborne polyurethane dispersion is Wanhua 4221; the organofluorine modified waterborne acrylic resin is Shanghai Xunda New Materials Co., Ltd. HD-830.

[0008] Furthermore, the weight ratio of the modified waterborne polyurethane dispersion to the organofluorine modified waterborne acrylic resin is 1:(0.5~1).

[0009] This invention discovers that by combining a modified waterborne polyurethane dispersion with an organofluorine-modified waterborne acrylic resin, especially at a weight ratio of 1:(0.5~1), a balance is achieved in film adhesion, stain resistance, and density. The possible reasons are: the urethane groups of the modified waterborne polyurethane dispersion can form hydrogen bonds and chemically adsorb onto the hydroxyl and amino groups on the substrate surface, ensuring adhesion; its soft and hard segment structure also imparts good flexibility to the film. The fluorocarbon segments of the organofluorine-modified waterborne acrylic resin have extremely low surface energy, significantly reducing the adhesion of contaminants; simultaneously, the acrylic backbone exhibits excellent compatibility with the polyurethane dispersion. At this ratio, the polyurethane dispersion provides sufficient adhesion sites, while the fluoroacrylic resin ensures stain resistance, resolving the contradiction between poor stain resistance of a single polyurethane dispersion and weak adhesion of a single fluoroacrylic resin.

[0010] Furthermore, the superhydrophobic filler is superhydrophobic acrylate micro powder.

[0011] Furthermore, the superhydrophobic acrylate micropowder has a contact angle greater than 150° and a roll-off angle less than 10°.

[0012] Furthermore, the weight ratio of the composite waterborne resin to the superhydrophobic filler is (15-25):1.

[0013] Maintaining a weight ratio of composite waterborne resin to superhydrophobic filler of (15-25:1) is a control parameter that achieves the optimal balance between stain resistance and overall performance of the coating film, ensuring that the superhydrophobic filler is distributed in the resin matrix in the most effective form and concentration. The superhydrophobic acrylate micropowder needs to be fully wetted and encapsulated by the resin matrix to achieve stable dispersion and avoid agglomeration. If the resin ratio is too low, the resin is insufficient to completely coat the filler particles, leading to uneven dispersion, sedimentation, and stress defects in the coating film, directly damaging its density, transparency, and water resistance. If the resin ratio is too high, a continuous and effective hydrophobic enhancement effect cannot be formed. This ratio ensures sufficient dispersion of the filler in the system while avoiding excessive addition that would reduce the water resistance of the coating film.

[0014] Furthermore, the defoamer includes at least one of BYK024 and Tego825.

[0015] The wetting agent includes at least one of TEGO4100 and SN4741.

[0016] The film-forming aid includes at least one of dipropylene glycol methyl ether, dipropylene glycol butyl ether, and dipropylene glycol methyl ether butyl ether.

[0017] The leveling agent includes at least one of Tego410 and PW336.

[0018] The thickener is a polyurethane thickener, such as Deqian 299 or Mingling PUR44.

[0019] This invention also provides a method for preparing the aforementioned water-based, highly stain-resistant, transparent topcoat, comprising the following steps: (1) Mix the modified waterborne polyurethane dispersion and the organofluorine modified waterborne acrylic resin, and add the pH adjuster, defoamer and wetting agent in sequence at a speed of 500-1000 r / min. Stir for 2-5 min to obtain mixture one. (2) Premix the film-forming aid with 5-7 parts by weight of water, add it to mixture one, and stir at a speed of 500-1000 r / min for 3-8 min to obtain mixture two; (3) Add superhydrophobic filler to mixture 2 and disperse at high speed for 20-40 min at a speed of 800-1200 r / min; then add leveling agent and the remaining water in sequence and continue to disperse for 3-8 min; finally add thickener, adjust the viscosity to about 72 KU, stir at low speed for 20-40 min to stabilize the system, and filter to obtain the water-based high stain-resistant transparent topcoat.

[0020] Beneficial effects: 1. This invention achieves high hardness, excellent stain resistance, outstanding water resistance and good adhesion of the paint film by scientifically compounding modified waterborne polyurethane dispersion with organic fluorine-modified waterborne acrylic resin, and by synergizing with superhydrophobic acrylate micro powder.

[0021] 2. This invention, through an optimized additive system and a step-by-step feeding and controlled-speed dispersion preparation process, ensures the full dispersion and compatibility of each component, effectively solving problems such as residual bubbles and poor leveling in the system. The resulting paint film has a smooth and even appearance without defects such as pinholes.

[0022] 3. This invention selects superhydrophobic acrylate micro powder as filler and mixes it with composite waterborne resin in a ratio of (15-25):1. This not only utilizes its micro-rough structure and low surface energy characteristics to improve the stain resistance level to level 1, but also ensures the transparency of the paint film and avoids the turbidity problem caused by traditional fillers. 4. This invention optimizes the stirring speed and time in stages to ensure uniform dispersion of each component, avoid agglomeration of superhydrophobic fillers, and minimize the fluctuation of product viscosity and performance between batches, making it suitable for large-scale industrial production. Detailed Implementation Unless otherwise specified, the experimental methods described in the following embodiments of the present invention are generally performed under conventional conditions or as recommended by the manufacturer. All commonly used chemical reagents used in the embodiments are commercially available products.

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1 Embodiment 1 of the present invention provides a water-based, highly stain-resistant, transparent topcoat, comprising the following components by weight, the formulation of which is shown in Table 1.

[0025] Table 1

[0026] Example 1 of the present invention provides a method for preparing a water-based, highly stain-resistant, transparent topcoat, comprising the following steps: (1) In a mixing tank, add modified waterborne polyurethane dispersion and organic fluorine modified waterborne acrylic resin. At a speed of 800 r / min, add pH adjuster, defoamer and wetting agent in sequence and stir for 3 minutes.

[0027] (2) Mix 5 parts of film-forming aid with 6 parts of water evenly, add it to the mixture in step 1, and disperse at 800 r / min for 5 minutes.

[0028] (3) Increase the rotation speed to 1000 r / min, add superhydrophobic acrylate micro powder, and disperse for 30 minutes; add leveling agent and the remaining 2.9 parts of water, and continue to disperse for 5 minutes at a rotation speed of 1000 r / min; finally add thickener and adjust the viscosity to 72 KU to obtain the water-based high stain-resistant transparent topcoat.

[0029] Example 2 The specific implementation method is the same as in Example 1, except that the defoamer BYK-024 is replaced with Tego825 and the wetting agent TEGO4100 is replaced with Shenzhu SN-4741.

[0030] Example 3 The specific implementation method is the same as in Example 1, except that the thickener Deqian 299 is replaced with Mingling PUR-44.

[0031] Comparative Example 1 The specific implementation method is the same as in Example 1, except that the modified waterborne polyurethane dispersion and the organofluorine modified waterborne acrylic resin are both replaced with acrylic emulsion, model: Dow 3311; and the wetting agent TEGO4100 is replaced with Shenzhu SN-4741.

[0032] Comparative Example 2 The specific implementation method is the same as in Example 1, except that: the modified waterborne polyurethane dispersion and the organofluorine modified waterborne acrylic resin are both replaced with the modified waterborne polyurethane dispersion, model: Yinyang PU617A; the defoamer BYK-024 is replaced with Tego825; and the wetting agent TEGO4100 is replaced with Shenzhu SN-4741.

[0033] Comparative Example 3 The specific implementation method is the same as in Example 1, except that: the organic fluorine modified waterborne acrylic resin is replaced with modified waterborne polyurethane dispersion, model: Wanhua 4221; the defoamer BYK-024 is replaced with Tego825; and the wetting agent TEGO4100 is replaced with Shenzhu SN-4741.

[0034] Comparative Example 4 The specific implementation method is the same as in Example 1, except that: the modified waterborne polyurethane dispersion is replaced with organic fluorine modified waterborne acrylic resin, model: Xunda HD-830; the defoamer BYK-024 is replaced with Tego825; and the wetting agent TEGO4100 is replaced with Shenzhu SN-4741.

[0035] Comparative Example 5 The specific implementation method is the same as in Example 1, except that the superhydrophobic acrylate micro powder is replaced with silica, model Grace SY-7000.

[0036] Comparative Example 6 The specific implementation method is the same as in Example 1, except that the superhydrophobic acrylate micro powder is replaced with polymethylurea resin, model number Albemarle M5.

[0037] Comparative Example 7 The specific implementation method is the same as in Example 1, except that the amount of superhydrophobic acrylate micro powder is adjusted to 6 parts and the amount of water is adjusted to 6.9 parts. In the preparation method of water-based high stain-resistant transparent topcoat, the amount of water in step (3) is adjusted to 0.9 parts.

[0038] Performance testing The water-based highly stain-resistant transparent topcoats prepared in the examples and comparative examples were subjected to performance tests, and the test results are shown in Table 2.

[0039] Table 2

[0040] As can be seen from the table above, the water-based transparent topcoat prepared in Examples 1-3 of the present invention exhibits excellent performance in all aspects, achieving an ideal balance of high stain resistance, water resistance, high adhesion, and moderate hardness.

[0041] Comparative Examples 1-4 show that using a single acrylic acid, modified waterborne polyurethane dispersion, or organofluorine modified waterborne acrylic resin cannot simultaneously achieve stain resistance, water resistance, and paint film appearance, thus proving the necessity of composite resin systems.

[0042] Comparative Examples 5-6 show that replacing superhydrophobic acrylate micropowder with silica or common organic matting powder results in a significant decrease in stain resistance and water resistance, demonstrating the crucial role of this specific filler.

[0043] Comparative Example 7 shows that the amount of filler added beyond the preferred range of the present invention will impair the water resistance of the coating film, demonstrating the importance of optimizing the component ratio.

[0044] In summary, through synergistic innovation in components and processes, this invention has successfully prepared a water-based, highly stain-resistant, transparent topcoat with excellent overall performance.

Claims

1. A waterborne high stain resistant clear topcoat, characterized by, The composition comprises the following components by weight parts: composite water-based resin 70-85 parts, pH regulator 0.05-0.15 parts, defoaming agent 0.4-0.8 parts, wetting agent 0.3-0.7 parts, film forming aid 4-6 parts, super-hydrophobic filler 3-5 parts, leveling agent 0.2-0.4 parts, thickening agent 0.4-0.8 parts and water 5-10 parts. The composite water-based resin is a combination of modified water-based polyurethane dispersion and organic fluorine modified water-based acrylic resin.

2. The waterborne high stain-resistant clear topcoat according to claim 1, characterized in that, The weight ratio of the modified water-based polyurethane dispersion and the organic fluorine modified water-based acrylic resin is 1: (0.5-1).

3. The waterborne high stain resistant clear topcoat according to claim 1, characterized in that, The super-hydrophobic filler is a super-hydrophobic acrylate micro powder.

4. The waterborne high stain resistant clear topcoat of claim 1, wherein, The weight ratio of the composite water-based resin and the super-hydrophobic filler is (15-25):

1.

5. The waterborne high stain resistant clear topcoat of claim 1, wherein, The defoaming agent comprises at least one of BYK024 and Tego825.

6. The waterborne high stain resistant clear topcoat of claim 1, wherein, The wetting agent comprises at least one of TEGO4100 and SN4741.

7. The waterborne high stain resistant clear topcoat of claim 1, wherein, The film forming aid comprises at least one of dipropylene glycol methyl ether, dipropylene glycol butyl ether and dipropylene glycol methyl ether butyl ether.

8. The waterborne high stain resistant clear topcoat of claim 1, wherein, The leveling agent comprises at least one of Tego410 and PW336.

9. The waterborne high stain resistant clear topcoat of claim 1, wherein, The thickening agent is a polyurethane thickening agent, which comprises at least one of Decon 299 and Mingling PUR44.

10. A method for preparing the aqueous high-stain- resistant clear topcoat according to any one of claims 1 to 9, characterized in that, The method comprises the following steps: (1) mixing the modified water-based polyurethane dispersion and the organic fluorine modified water-based acrylic resin, adding the pH regulator, the defoaming agent and the wetting agent in turn at a rotation speed of 500-1000 r / min, stirring for 2-5 min to obtain a mixture one; (2) premixing the film forming aid with 5-7 parts by weight of water, adding the mixture one, stirring at a rotation speed of 500-1000 r / min for 3-8 min to obtain a mixture two; (3) adding the super-hydrophobic filler to the mixture two, dispersing at a rotation speed of 800-1200 r / min for 20-40 min; then adding the leveling agent and the remaining water in turn, continuing to disperse for 3-8 min, finally adding the thickening agent to adjust the viscosity to 70-80 KU to obtain the water-based high stain-resistant transparent finish.

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