Waterborne single-component dip-coating paint for construction machinery chassis and preparation method thereof

Abstract

This invention relates to the field of water-based dip coating technology, specifically to a water-based single-component dip coating for engineering machinery chassis and its preparation method. The raw materials for preparing the water-based single-component dip coating, by weight, include: 10-20 parts self-emulsifying modified acrylic resin, 20-40 parts acrylic emulsion, 0.3-0.5 parts dimethylethanolamine, 1-7 parts ethylene glycol butyl ether, 0.1-1 parts defoamer, 1-3 parts water-based dispersant, 0.2-0.5 parts fumed silica, 0.2-0.5 parts bentonite, 10-25 parts pigment, 0.2-0.6 parts water-based drier, 0.5-2.5 parts film-forming aid, 0.2-0.5 parts substrate wetting agent, 0.3-0.7 parts flash rust inhibitor, 0.1-0.3 parts leveling agent, 0.1-0.3 parts thickener, and 20-50 parts deionized water. The water-based single-component dip coating for engineering machinery chassis provided by this invention has excellent oil resistance, can be applied with oil, does not rust, has excellent water resistance and salt spray resistance, low VOC content, and is environmentally friendly.

Description

Technical Field

[0001] This invention relates to the field of water-based dip coating technology, specifically to a water-based single-component dip coating for engineering machinery chassis and its preparation method. Background Technology

[0002] As the core load-bearing components of construction machinery, the coating quality of chassis parts directly affects the service life and operational safety of the equipment. Currently, solvent-based coatings are commonly used in the industry, and the coating operation of chassis parts is completed through dip coating process. This process is widely used in traditional production and can achieve uniform coverage of the component surface.

[0003] However, traditional solvent-based coatings have significant drawbacks. The large amounts of volatile organic compounds (VOCs) they contain are released during application and use, not only producing a strong odor and directly harming the respiratory system and health of workers, but also exacerbating air pollution, which is inconsistent with current environmental protection trends. With increasing global environmental awareness and increasingly stringent environmental regulations in various countries, the application scenarios for solvent-based coatings are severely limited, making the development of environmentally friendly alternatives an urgent industry need.

[0004] While water-based single-component dip coatings have gradually replaced some solvent-based products on the current market, they still have many performance shortcomings. Most products use acrylic emulsions as the main film-forming substance, resulting in poor oil resistance and difficulty in meeting the actual production needs of coating chassis components with oil, and the paint film is prone to cracking. Furthermore, existing water-based dip coatings are prone to paint residue on edges and corners during application, and coated parts are prone to rusting. Their key protective properties, such as water resistance and salt spray resistance, also fail to meet the stringent requirements of engineering machinery chassis, hindering the large-scale application of water-based coatings in this field. Therefore, developing a water-based single-component dip coating for engineering machinery chassis that combines environmental friendliness with excellent protective performance has become an urgent technical problem to be solved in this field. Summary of the Invention

[0005] To address the aforementioned technical problems, the first aspect of this invention provides a water-based single-component dip coating for engineering machinery chassis. The raw materials for its preparation, by weight, include: 10-20 parts self-emulsifying modified acrylic resin, 20-40 parts acrylic emulsion, 0.3-0.5 parts dimethylethanolamine, 1-7 parts ethylene glycol butyl ether, 0.1-1 parts defoamer, 1-3 parts water-based dispersant, 0.2-0.5 parts fumed silica, 0.2-0.5 parts bentonite, 10-25 parts pigment, 0.2-0.6 parts water-based drier, 0.5-2.5 parts film-forming aid, 0.2-0.5 parts substrate wetting agent, 0.3-0.7 parts anti-flash rust agent, 0.1-0.3 parts leveling agent, 0.1-0.3 parts thickener, and 20-50 parts deionized water.

[0006] As an example of implementation, the self-emulsifying modified acrylic resin has a dynamic viscosity of 10,000-80,000 mPa·s at 25°C.

[0007] Furthermore, the self-emulsifying modified acrylic resin is grade 3EA0402B (70% solids content, viscosity 10000-80000 mPa•s), purchased from Guangdong Tongde New Materials Co., Ltd.

[0008] In this invention, self-emulsifying modified acrylic resin 3EA0402B is selected as the core film-forming material for water-based single-component dip coating. On the one hand, after drying, it can form a dense resin film, becoming a core barrier for chassis components to resist water and salt spray corrosion, which is conducive to achieving the key performance indicators of water resistance ≥168h and salt spray resistance ≥168h. At the same time, it ensures the zero-level adhesion between the paint film and the metal substrate, achieving the effect of no paint peeling when coated with oil. On the other hand, self-emulsifying modified acrylic resin 3EA0402B has its own self-emulsifying properties. After neutralization with dimethyl ethanolamine, it can be stably dispersed in water without the addition of additional emulsifiers, effectively avoiding the problems of layering and resin precipitation during paint storage, and ensuring the uniformity of the paint solution. In addition, its high viscosity of 10000-80000 mPa·s at 25°C can encapsulate pigment particles, reducing the risk of paint film cracking. At the same time, it complements the acrylic emulsion, balancing the hardness and flexibility of the paint film, and adapting to the requirements of dip coating process for paint flowability and film integrity.

[0009] As an example of implementation, the acrylic emulsion is an anionic acrylic emulsion.

[0010] Furthermore, the viscosity of the anionic acrylic emulsion at 25°C is ≤1000 cps.

[0011] Furthermore, the acrylic emulsion mentioned is model 5111 acrylic emulsion, purchased from Guangdong Huaguoshan Environmental Protection Technology Co., Ltd.

[0012] In this invention, 5111 acrylic emulsion is selected as a core film-forming aid. It enhances the flexibility and crack resistance of the paint film. The minimum film-forming temperature of 5111 acrylic emulsion is 40℃. It can synergistically form a film with the self-emulsifying modified acrylic resin 3EA0402B, effectively reducing the brittleness of the paint film and achieving a film flexibility of 2mm, thus preventing the paint film from cracking due to vibration during the use of engineering machinery chassis components. Secondly, 5111 acrylic emulsion has a milky white to slightly blue phase and a viscosity ≤1000cps at 25℃, which can adjust the overall fluidity of the paint. With the help of additives such as ethylene glycol butyl ether, the application viscosity is controlled at 70-90S, ensuring that the paint can evenly cover the surface of the chassis components without any missed areas during dip coating. The anionic properties of 5111 acrylic emulsion are compatible with the pH value of the system (6-8), and can synergistically disperse pigments with 3EA0402B resin, preventing the paint from separating during storage. At the same time, it can also improve the density of the paint film and help enhance the water resistance of the paint film.

[0013] As an example of implementation, the defoamer is an organosilicone defoamer.

[0014] Furthermore, the silicone defoamer includes TJ3910 defoamer and Tego 902W defoamer.

[0015] Furthermore, the mass ratio of the TJ3910 defoamer to the Tego 902W defoamer is (0.1-0.2):(0.3-0.5).

[0016] TJ3910 defoamer works synergistically with Tego 902W defoamer to comprehensively address air bubble issues in paint preparation and application through complementary functions of early-stage foam suppression and late-stage foam breaking. TJ3910 defoamer primarily suppresses foam during the grinding and dispersion stage, preventing air entrainment and the formation of numerous air bubbles during high-speed grinding of pigments and functional additives, thus avoiding uneven pigment dispersion caused by air bubbles. Tego 902W defoamer prevents secondary foaming during paint mixing and application, eliminating residual air bubbles generated by adding emulsions and additives during paint mixing. Simultaneously, it prevents pinholes and craters on the paint film surface due to bubble rupture during dip coating. The combined effect ensures system stability during paint preparation and guarantees a smooth final paint film appearance, meeting the surface quality requirements for engineering machinery chassis paints.

[0017] As an example of implementation, the aqueous dispersants include TJ6020 wetting and dispersing agent and TJ6290W wetting and dispersing agent.

[0018] Furthermore, the mass ratio of the TJ6020 wetting and dispersing agent to the TJ6290W wetting and dispersing agent is (0.5-2):(0.5-1).

[0019] TJ6020 wetting and dispersing agent can quickly penetrate into the gaps between pigment particles, breaking up initial agglomerates; the molecules of TJ6290W wetting and dispersing agent can adsorb onto the surface of finely ground pigment particles, forming a charge barrier and steric hindrance, preventing particles from re-agglomerating. The combination of these two agents ensures that the pigment is ground to a fineness of ≤25μm, while also ensuring uniform pigment dispersion during paint storage and application, preventing uneven gloss and reduced hiding power caused by particle agglomeration, while simultaneously reducing grinding resistance and improving preparation efficiency.

[0020] As an feasible example, the fumed silica is hydrophobic fumed silica with a mesh size of 1000-2000 mesh.

[0021] Furthermore, the fumed silica is graded H15 and supplied by Wacker Chemie AG of Germany.

[0022] The hydrophobic surface of fumed silica H15 reduces the binding of water molecules in aqueous systems, forming a three-dimensional network structure that efficiently encapsulates pigment particles, preventing stratification and sedimentation during long-term storage and solving the problem of uneven paint consistency caused by pigment precipitation. On the other hand, this network structure is thixotropic, maintaining the viscosity of the system and preventing sedimentation when stationary, and being broken down by shear forces during grinding or dip coating, thus reducing the viscosity and ensuring the fluidity of the paint is suitable for dip coating processes. It also helps to improve the anti-sagging properties of the paint film, ensuring the coating quality of chassis parts and corners.

[0023] As an example of an implementable practice, the pigments mentioned include rutile titanium dioxide, iron oxide yellow, 139 organic medium yellow, and 151 organic lemon yellow.

[0024] Furthermore, the mass ratio of the rutile titanium dioxide, iron oxide yellow, 139 organic medium yellow and 151 organic tartrazine is (3-7):(4-7):(1-3):(3-5).

[0025] As an feasible example, the water-based drying agent is XY-6001 drying agent (a cobalt-containing composite drying agent, dissolved in a water-based co-solvent, with an active ingredient content of >40%), which can be purchased from Changzhou Xinbei District Xuanyue Chemical Co., Ltd.

[0026] As an implementable example, the film-forming aid is Eastman Texanol (2,2,4-trimethyl-1,3-pentanediol monoisobutyrate).

[0027] Eastman Texanol components assist in efficient film formation, reducing the minimum film-forming temperature of 5111 acrylic emulsion and solving the problem of incomplete film formation at low temperatures, thus preventing undercoat defects and pinholes. Simultaneously, it enhances film performance by delaying evaporation to allow for full cross-linking, improving water resistance and flexibility. It also optimizes pigment color development, preventing uneven gloss, and works synergistically with thickeners to stabilize dip-coating viscosity, ensuring uniform coverage of the chassis edges and corners and improving paint application.

[0028] As an example of implementation, the substrate wetting agent is TJ-175 substrate wetting agent, which can be purchased from Hangzhou Lin'an Taiju Polymer Materials Co., Ltd.

[0029] TJ-175 substrate wetting agent improves substrate wettability and quickly reduces the surface tension of the paint, allowing the paint to spread evenly on the metal substrate surface. This solves the technical problem of "pouring in without coating and pinholes" when dipping in oil, ensuring full coverage. At the same time, by improving the penetration and adhesion of the paint to the substrate, it lays the foundation for a strong bond between the paint film and the substrate. Combined with resin and anti-flash rust agent, it further ensures Grade 0 adhesion, preventing the paint film from peeling off later.

[0030] As an example of an implementable method, the flash rust inhibitor is DefrostT790, which is available from Hoffmann Chemicals.

[0031] Defrost T790 anti-flash rust agent can quickly adhere to the surface of the metal chassis, forming a temporary protective film that isolates the substrate from moisture and oxygen after application until the paint film is completely dry. This prevents flash rust (i.e., localized pitting corrosion) from appearing on the substrate in a short period of time due to residual moisture in water-based paint. On the other hand, Defrost T790 anti-flash rust agent works synergistically with the resin and pigments in the paint film to enhance the adhesion and density of the paint film to the substrate, extend the effective period of salt spray and water resistance, and ensure the protective stability of chassis components in humid or harsh environments.

[0032] As an example of implementation, the leveling agent is BYK-346 silicone leveling agent.

[0033] BYK-346 silicone leveling agent reduces the surface tension of the paint, thereby reducing pinholes caused by surface tension differences after dipping, resulting in a smoother paint film surface after drying. At the same time, it can reduce paint accumulation or missed areas at the edges and gaps of chassis components, and prevent cracking of the paint film due to uneven shrinkage during the drying process, ensuring the uniformity and integrity of the paint film appearance.

[0034] As an example of implementation, the thickener is HW-0716 water-based thickener, which can be purchased from Zhuhai Tongzhou New Materials Co., Ltd.

[0035] HW-0716 water-based thickener increases the viscosity of the system, adjusting the paint to the required 70-90S (T-4 cup) range for dip coating. This prevents the paint film from being too thin or sagging due to excessively low viscosity, or from being too high viscosity affecting uniform paint coverage. Simultaneously, the thickener stabilizes the paint's condition and film quality, enhancing its stability during storage, reducing pigment settling, and slowing down moisture evaporation during film drying. This helps improve leveling properties and prevents defects such as cracking and orange peel caused by rapid moisture loss, ensuring optimal coating results.

[0036] A second aspect of the present invention provides a method for preparing a water-based single-component dip coating for engineering machinery chassis, comprising: The self-emulsifying modified acrylic resin, acrylic emulsion, dimethyl ethanolamine, ethylene glycol butyl ether, defoamer, water-based dispersant, fumed silica, bentonite, pigment, water-based drier, film-forming aid, substrate wetting agent, flash rust inhibitor, leveling agent, thickener, and deionized water are mixed evenly to obtain a water-based single-component dip coating for engineering machinery chassis.

[0037] The water-based single-component dip coating for engineering machinery chassis prepared by this invention can be applied by simply adding water to adjust the concentration to a suitable level during actual use.

[0038] Beneficial effects (i) The water-based single-component dip coating for engineering machinery chassis prepared by this invention has a VOC ≤ 150g / L during construction. It is an environmentally friendly water-based coating. Compared with traditional solvent-based dip coatings, it significantly reduces the emission of volatile organic compounds, reduces the harm to the health of operators and the pollution to the environment, and meets the requirements of stringent environmental protection regulations.

[0039] (ii) The water-based single-component dip coating of the engineering machinery chassis prepared by the present invention has a water resistance of ≥168h, a salt spray resistance of ≥168h, and an aging resistance of ≥100h. It can effectively resist the water immersion, salt spray corrosion and aging problems faced by the engineering machinery chassis during use, provide long-term protection for chassis components and extend the service life of equipment.

[0040] (III) The water-based single-component dip coating for engineering machinery chassis prepared by the present invention supports oil-based dip coating, has good wettability to the substrate, and only 1-5% deionized water needs to be added during construction to adjust the viscosity before dip coating. It can also solve the problem of paint not sticking to the edges and corners of traditional water-based dip coatings, ensuring uniform coating of chassis parts (including edges and corners and gaps), improving construction efficiency and coating integrity.

[0041] (iv) The water-based single-component dip coating obtained by the present invention has a coating film adhesion of grade 0 (GB / T9286 standard), a hardness of HB, a flexibility of 2mm, and an impact strength of >50Kg. It has good adhesion, impact resistance and crack resistance, and can adapt to complex working conditions such as vibration and stress of engineering machinery chassis, avoiding paint film peeling or damage.

[0042] (v) In the water-based single-component dip coating raw material formula of the present invention, the various additives work synergistically to prevent problems such as layering and pigment sedimentation during the storage of the coating, thus ensuring the uniformity of the paint liquid; at the same time, the paint film is less prone to defects such as pinholes, shrinkage craters, and orange peel during the drying process, resulting in a smooth appearance and a gloss level of 35-43°, which meets the appearance quality requirements of chassis parts. Detailed Implementation

[0043] Example Examples 1-4: The first aspect provides a water-based single-component dip coating for engineering machinery chassis, the specific information of the raw materials for its preparation is shown in Table 1.

[0044] Table 1

[0045] Example 1-4, the second aspect, provides a method for preparing a water-based single-component dip coating for engineering machinery chassis, comprising: mixing the raw materials in Table 1 evenly according to the specified mass parts to obtain the water-based single-component dip coating for engineering machinery chassis.

[0046] The self-emulsifying modified acrylic resin 3EA0402B has a solid content of 67-71 wt% and a dynamic viscosity of 10000-80000 mPa·s at 25°C. It was purchased from Guangdong Tongde New Materials Co., Ltd.

[0047] The dimethylethanolamine mentioned is of chemical purity grade.

[0048] The ethylene glycol butyl ether is of chemical purity grade.

[0049] The deionized water mentioned is grade III water.

[0050] The TJ3910 defoamer is an organosilicon defoamer, purchased from Hangzhou Lin'an Taiju Polymer Materials Co., Ltd.

[0051] Both the wetting and dispersing agents TJ6020 and TJ6290W were purchased from Hangzhou Lin'an Taiju Polymer Materials Co., Ltd.

[0052] The specific grade of the (hydrophobic) fumed silica is Wacker H15 from Germany.

[0053] The specific grade of the bentonite mentioned is Hemings (BENTONEEW).

[0054] The specific grade of the rutile titanium dioxide is Lomon Billions R996 titanium dioxide.

[0055] The specific grade of the iron oxide yellow mentioned is Huayuan NO313 iron oxide yellow.

[0056] The specific brand name of the organic yellow 139 mentioned above is Seven Color 139 Yellow.

[0057] The specific brand name of the 151 organic lemon yellow is Rainbow 151 Yellow.

[0058] The specific brand of the XY-6001 drying agent (water-based drying agent) is Changzhou Xuanyue Chemical XY-6001 drying agent.

[0059] The 5111 acrylic emulsion was purchased from Guangdong Huaguoshan Environmental Protection Technology Co., Ltd., and its specific indicators are as follows: milky white with a slight blue phase emulsion, minimum film-forming temperature of 40℃, solid content of 46.0±1, viscosity (25℃, cps) ≤1000, pH=6-8, and anionic acrylic emulsion.

[0060] The main component of the aforementioned EastmanTexanol (film-forming aid) is a dodecyl alcohol ester (C12 alcohol ester), which was purchased from Eastman Chemical Company.

[0061] The TJ175 substrate wetting agent was purchased from Hangzhou Lin'an Taiju Polymer Materials Co., Ltd.

[0062] The T-790 anti-flash rust agent was purchased from the Hoffmann Group.

[0063] The Tego 902W defoamer was purchased from DIG Chemical.

[0064] The BYK-346 leveling agent is an organosilicon leveling agent, purchased from BYK Chemical.

[0065] The HW-0716 water-based thickener was purchased from Zhuhai Tongzhou New Materials Co., Ltd.

[0066] The performance of the water-based single-component dip coatings prepared in Examples 1-4 was tested, and the test results are shown in Table 2.

[0067] Table 2

[0068] The experimental results in Table 2 show that the water-based single-component dip coating for engineering machinery chassis provided by this invention has excellent anti-oil properties, can be applied with oil, does not rust, has excellent water and salt spray resistance, low VOC content, and is environmentally friendly.

Claims

1. A water-based single-component dip coating for engineering machinery chassis, characterized in that, The raw materials, by weight, include: 10-20 parts self-emulsifying modified acrylic resin, 20-40 parts acrylic emulsion, 0.3-0.5 parts dimethylethanolamine, 1-7 parts ethylene glycol butyl ether, 0.1-1 parts defoamer, 1-3 parts aqueous dispersant, 0.2-0.5 parts fumed silica, 0.2-0.5 parts bentonite, 10-25 parts pigment, 0.2-0.6 parts aqueous drier, 0.5-2.5 parts film-forming aid, 0.2-0.5 parts substrate wetting agent, 0.3-0.7 parts anti-flash rust agent, 0.1-0.3 parts leveling agent, 0.1-0.3 parts thickener, and 20-50 parts deionized water.

2. The water-based single-component dip coating for engineering machinery chassis according to claim 1, characterized in that, The self-emulsifying modified acrylic resin has a dynamic viscosity of 10,000-80,000 mPa·s at 25°C.

3. The water-based single-component dip coating for engineering machinery chassis according to claim 2, characterized in that, The grade of the self-emulsifying modified acrylic resin is 3EA0402B.

4. The water-based single-component dip coating for engineering machinery chassis according to claim 1, characterized in that, The acrylic emulsion mentioned is an anionic acrylic emulsion.

5. The water-based single-component dip coating for engineering machinery chassis according to claim 4, characterized in that, The viscosity of the anionic acrylic emulsion at 25°C is ≤1000cps.

6. The water-based single-component dip coating for engineering machinery chassis according to claim 4, characterized in that, The acrylic emulsion is designated as 5111 acrylic emulsion.

7. The water-based single-component dip coating for engineering machinery chassis according to claim 1, characterized in that, The fumed silica mentioned is hydrophobic fumed silica with a mesh size of 1000-2000 mesh.

8. The water-based single-component dip coating for engineering machinery chassis according to any one of claims 1-7, characterized in that, The pigments include rutile titanium dioxide, iron oxide yellow, 139 organic medium yellow, and 151 organic lemon yellow.

9. The water-based single-component dip coating for engineering machinery chassis according to claim 8, characterized in that, The mass ratio of the rutile titanium dioxide, iron oxide yellow, 139 organic medium yellow and 151 organic tartrazine is (3-7):(4-7):(1-3):(3-5).

10. A method for preparing a water-based single-component dip coating for an engineering machinery chassis according to any one of claims 1-9, characterized in that, Includes the following steps: The self-emulsifying modified acrylic resin, acrylic emulsion, dimethyl ethanolamine, ethylene glycol butyl ether, defoamer, water-based dispersant, fumed silica, bentonite, pigment, water-based drier, film-forming aid, substrate wetting agent, flash rust inhibitor, leveling agent, thickener, and deionized water are mixed evenly to obtain a water-based single-component dip coating for engineering machinery chassis.

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