A waterproof and heat-insulating aerosol coating, its preparation method and application

Abstract

This invention discloses a waterproof and heat-insulating aerosol coating, its preparation method, and its application. The coating, by weight, comprises the following components: 20-30 parts polydimethylsiloxane, 5-15 parts polyvinylidene fluoride, 5-10 parts dimethyl 3,3'-dithiodipropionate, 1-5 parts transesterification inhibitor, 10-15 parts propellant, 5-10 parts dispersant, 20-40 parts solvent, and 1-15 parts pigment. The coating of this invention can quickly form a film after spraying, constructing a dense waterproof barrier on the substrate surface to prevent moisture penetration, significantly improving the waterproof performance of the coating. It can also significantly reduce temperature transfer under high-temperature exposure conditions, maintaining the temperature difference between the inside and outside of the substrate, providing an effective heat insulation solution for industrial equipment and automotive surfaces.

Description

Technical Field

[0001] This invention relates to the field of surface protective coating technology, and in particular to a waterproof and heat-insulating aerosol coating, its preparation method, and its application. Background Technology

[0002] With increasingly stringent requirements for surface protection in buildings, electronic devices, automobiles, and other industries, significant progress has been made in the research and application of surface repair coatings. Traditional repair coatings are typically used to protect the surfaces of equipment and buildings, extending their lifespan, improving aesthetics, and enhancing protective performance. However, most existing surface repair coatings focus on optimizing a single function, such as waterproofing, corrosion resistance, or thermal insulation, making it difficult to simultaneously achieve multiple performance characteristics. This is especially true for aerosol coatings, where coatings combining waterproofing and thermal insulation are still relatively scarce.

[0003] Aerosol coatings have been widely used in recent years due to their convenient application, uniform coverage, and suitability for complex surfaces. However, existing aerosol coatings mainly focus on basic functions such as waterproofing and corrosion resistance, making it difficult to simultaneously achieve both waterproofing and thermal insulation properties while aerosol spraying. On the one hand, waterproof coatings typically achieve their waterproofing through hydrophobic resins (such as silicone resins and fluorocarbon resins), but these resins contribute little to thermal insulation. On the other hand, thermal insulation coatings often rely on microporous materials or ceramic powders to reduce thermal conductivity, but these materials are highly hydrophilic and easily absorb moisture in humid environments, reducing their waterproofing effect and even causing the coating to fail or peel off.

[0004] Furthermore, the compatibility of traditional heat insulation and waterproofing functions usually requires precise proportions of various components, and must ensure rapid film formation and maintain a long-lasting and stable protective effect in aerosol form. However, the rapid film formation time and limited coating thickness of aerosol coatings make the stability of the composite composition a major challenge. Simultaneously, under aerosol conditions, the composite material needs to have appropriate particle size and dispersibility to ensure uniformity and stability of the spray. Therefore, how to achieve both waterproofing and heat insulation effects in existing aerosol coatings, while also ensuring ease of application and long-term performance, is a problem that urgently needs to be solved in current technology.

[0005] In conclusion, developing a high-performance coating with both waterproof and heat-insulating functions, suitable for aerosol spraying, can not only enhance the versatility of surface repair coatings but also meet the protection needs of various special environments, thus having broad application prospects. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention proposes a waterproof and heat-insulating aerosol coating, its preparation method, and its application.

[0007] This invention provides a waterproof and heat-insulating aerosol coating, comprising the following components by weight:

[0008] 20-30 parts of polydimethylsiloxane, preferably 23-28 parts; 5-15 parts of polyvinylidene fluoride, preferably 7-13 parts; 5-10 parts of dimethyl 3,3'-dithiodipropionate, preferably 6-8 parts; 1-5 parts of transesterification inhibitor, preferably 2-3 parts; 10-15 parts of propellant, preferably 12-14 parts; 5-10 parts of dispersant, preferably 6-8 parts; 20-40 parts of solvent, preferably 25-35 parts; and 1-15 parts of pigment.

[0009] Polyvinylidene fluoride (PVDF) possesses low surface energy, enabling it to form a dense hydrophobic layer that significantly enhances the waterproofing performance of coatings and reduces moisture retention on the coating surface. When compounded with dimethyl 3,3'-dithiodipropionate (DMD), it synergistically reduces surface energy, further enhancing the hydrophobicity of the coating. The strong CF bonds in the PVDF molecular structure endow it with extremely high thermal stability while reducing heat diffusion through the material. By compounding DMD with PVDF, a more efficient thermal barrier can be formed, more effectively blocking heat transfer and enhancing the thermal insulation capability of the coating.

[0010] In some embodiments, the transesterification inhibitor is any one of triphenyl phosphite, sodium acid pyrophosphate, and sodium dihydrogen phosphate. The transesterification inhibitor can prevent the decomposition or degradation of coating components and improve the long-term stability of the aerosol during use, especially its stability during storage or at different temperatures.

[0011] In some embodiments, the mass ratio of polyvinylidene fluoride to dimethyl 3,3'-dithiodipropionate is (0.8-3):1, preferably (1.5-2):1; further optimizing the amount of polyvinylidene fluoride and dimethyl 3,3'-dithiodipropionate can make the polyvinylidene fluoride more uniformly dispersed in the coating, forming a more complete hydrophobic network, and significantly improving the waterproof effect of the coating; in addition, it can further reduce the thermal conductivity and improve the heat insulation capacity of the coating.

[0012] In some embodiments, the solvent is a mixture of ester solvents and alcohol solvents or a mixture of ester solvents and ketone solvents, preferably a mixture of ester solvents and ketone solvents; the volatile characteristics of different solvent combinations can regulate the film-forming speed of the coating and optimize the coating quality; among them, ester solvents and ketone solvents have strong wettability on the substrate surface, which helps the coating to adhere firmly.

[0013] In some embodiments, the propellant is at least one selected from propane, butane, 1,1,1,2-tetrafluoroethane (HFC-134a), and dimethyl ether (DME).

[0014] In some embodiments, the dispersant is a multifunctional amine dispersant, a carboxylate dispersant, or a polyethyleneimine derivative dispersant; the multifunctional amine dispersant includes triethanolamine dispersant, dimethylethyleneamine dispersant, and quaternary ammonium salt compound (such as hexadecyltrimethylammonium chloride) dispersant; the carboxylate dispersant includes sodium dodecylbenzenesulfonate dispersant, sodium oleate dispersant, and sodium laurate dispersant; the polyethyleneimine derivative dispersant includes polyethyleneimine dispersant and polyethyleneimine-derived quaternary ammonium salt dispersant; the dispersant enables the solid components in the coating to be uniformly dispersed in the matrix material, avoiding aggregation and precipitation.

[0015] In some embodiments, the pigment is selected from either inorganic or organic pigments. The inorganic pigments include carbon black, titanium dioxide, chrome green, and phthalocyanine green; the organic pigments include toluidine red.

[0016] In some embodiments, the D50 particle size of the polyvinylidene fluoride (PVDF) is 0.5–1 μm; the D50 particle size of the pigment is 1–3 μm; and particle size is measured using a laser particle size analyzer. The particle size of PVDF and pigment directly affects the uniformity of the coating. Smaller particle sizes help the coating form a uniform and dense insulating layer on the substrate surface, reducing heat conduction and moisture penetration, and enhancing adhesion.

[0017] The present invention also provides a method for preparing the aforementioned waterproof and heat-insulating aerosol coating, comprising the following steps:

[0018] S1: Weigh each component according to the weight parts, add pigment to the dispersant and solvent, and disperse in a high-speed disperser until uniform;

[0019] S2: Add polydimethylsiloxane, polyvinylidene fluoride, dimethyl 3,3'-dithiodipropionate and transesterification inhibitor to the solvent, and stir and mix at 500-1000 rpm to obtain the coating mixture;

[0020] S3: In a closed system, the coating mixture described in S2 is filtered and filled into an aerosol can, an aerosol valve is installed, the can is sealed with a special aerosol sealing machine, a special aerosol filling machine is used to fill the propellant, and an atomizing nozzle is installed to produce a waterproof and heat-insulating aerosol coating.

[0021] In some implementations, the filling pressure of the inflator is controlled to be less than 0.8 MPa / 25°C.

[0022] The present invention also provides the application of the aforementioned waterproof and heat-insulating aerosol coating in outdoor building, ship surface or chassis coatings.

[0023] In summary, compared with the prior art, the present invention achieves the following technical effects:

[0024] 1. This invention, by compounding polyvinylidene fluoride with dimethyl 3,3'-dithiodipropionate, forms a highly hydrophobic structure on the coating surface, significantly improving the waterproof performance of the coating. After spraying, the coating can quickly form a film and construct a dense waterproof barrier on the substrate surface, preventing moisture penetration.

[0025] 2. The coating of the present invention can effectively block heat conduction after spraying. The coating can not only reduce the heat absorption rate of the substrate, but also significantly reduce the temperature transfer under high temperature exposure conditions, maintain the temperature difference between the inside and outside of the substrate, and provide an effective heat insulation solution for industrial equipment and automotive surfaces.

[0026] 3. The waterproof and heat-insulating aerosol coating of the present invention has good stability and can be stored for a long time in aerosol form, ensuring its ease of construction and long-term use. Detailed Implementation

[0027] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with 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 skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0028] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, all materials and reagents used are commercially available.

[0029] I. The raw materials used in the embodiments of the present invention are sourced as follows:

[0030] Polydimethylsiloxane: DOWSIL, DC184;

[0031] Polyvinylidene fluoride: Solvay, USA, 6012;

[0032] Dimethyl 3,3′-dithiodipropionate: Bost;

[0033] Ester exchange inhibitor #1: Triphenyl phosphite, CAS No. 101-02-0, Changhe Chemical;

[0034] Ester exchange inhibitor #2: Sodium acid pyrophosphate, CAS No. 7722-88-5, Wanxiang Hongrun;

[0035] Propellant #1: Propane, industrial grade, commercially available;

[0036] Propellant #2: Butane, industrial grade, commercially available;

[0037] Dispersant: Hydrophilic modified copolycarboxylate dispersant, Dow;

[0038] Solvent #1: 50% (v / v) ethyl acetate and 50% (v / v) methyl ethyl ketone;

[0039] Solvent #2: 70% (v / v) ethyl acetate and 10% (v / v) isopropanol;

[0040] Pigment: Carbon black, Zhongbei Chemical.

[0041] II. The preparation method of the waterproof and heat-insulating aerosol coatings of Examples 1-7 and Comparative Examples 1-6 of the present invention includes the following steps:

[0042] (1) The pigment and polyvinylidene fluoride were ground to a D50 particle size of 1 μm using a Hosokawa Alpine AFG air jet mill, and the particle size was tested using a Partica LA-960V2.

[0043] (2) Weigh each component by weight, slowly add the pigment to the mixture of dispersant and solvent while stirring to avoid clumping, and disperse it for 60 minutes at 3000 rpm using a high-speed disperser until the pigment is completely dispersed and a uniform pigment slurry is formed.

[0044] (3) In another stirred tank, add the solvent, polydimethylsiloxane, polyvinylidene fluoride, 3,3′-dithiodipropionate and transesterification inhibitor in sequence. After each component is added, stir at a low speed of 1000 rpm for 15 minutes to ensure thorough mixing.

[0045] (4) Gradually add the pigment slurry prepared in (2) to the mixture prepared in (3), and continue stirring for 30 minutes to ensure that the coating mixture is uniform. Use a 1000-mesh filter to filter out any large particles or impurities that may exist, and ensure the uniformity and flowability of the coating.

[0046] (5) In a closed system, the filtered paint mixture is filled into an aerosol can, with the filling volume accounting for 60-80% of the can volume. The aerosol valve is installed, and the can is sealed with a special aerosol sealing machine. Then, the propellant is filled in with a special aerosol filling machine, and the filling pressure is controlled to be less than 0.8MPa / 25℃. The atomizing nozzle is installed and sealed to ensure that the nozzle is not blocked and can atomize and spray normally.

[0047] The formulations of each embodiment and comparative example are shown in Tables 1-2.

[0048] Table 1. Technical solutions of the embodiments (parts by weight)

[0049]

[0050] Example 8: The difference from Example 1 is that the pigment is ground to a D50 particle size of 10 μm.

[0051] Example 9: The difference from Example 1 is that the polytetrafluoroethylene is ground to a D50 particle size of 10 μm.

[0052] Table 2 Comparative examples of technical solutions (parts by weight)

[0053]

[0054]

[0055] III. Performance Testing Methods

[0056] 1. Waterproof performance test

[0057] Adhesion test:

[0058] (1) Select a 5cm×5cm metal plate, ensure that the surface is flat, clean, and free of oil and dust, and spray the aerosol coating prepared in the examples and comparative examples evenly. The spray thickness is 3μm, and allow it to dry naturally for 24 hours.

[0059] (2) Adhesion tests were conducted according to GB / T9286-1998, and the results were divided into six levels, from level 0 to level 5:

[0060] Grade 0: The coating around the grid has no or very little peeling, and the adhesion is excellent.

[0061] Level 1: The area of ​​coating peeling is less than 5% of the total area of ​​the grid, but the peeling does not connect along the cutting line.

[0062] Level 2: The area of ​​coating peeling is 5% to 15% of the total area of ​​the grid, and the peeling does not connect along the cutting line.

[0063] Level 3: The area of ​​coating peeling is 15% to 35% of the total area of ​​the grid, and it is connected along the cutting line, but most of the entire coating is still retained.

[0064] Level 4: The area of ​​coating peeling is 35% to 65% of the total area of ​​the grid, with most of the coating peeling off and the exposed substrate clearly visible.

[0065] Level 5: The area of ​​coating peeling is greater than 65% of the total area of ​​the grid, and the coating has completely peeled off in almost the entire grid area, exposing the substrate.

[0066] (3) Immerse the metal plate completely in deionized water at 60°C for 24 hours;

[0067] (4) Remove the sample from the immersion medium and gently wipe the surface with absorbent paper to avoid damaging the coating;

[0068] (5) Measure the adhesion after treatment using the same method as the adhesion test in step (2).

[0069] Water resistance test:

[0070] (1) Select a 10cm×10cm metal plate, ensure that the surface is flat, clean, and free of oil and dust, and spray the aerosol coating prepared in the examples and comparative examples evenly. The spray thickness is 20μm, and allow it to dry naturally for 24 hours.

[0071] (2) Place a 10cm×10cm metal plate in an autoclave (Shanghai Jinpeng Instruments ZF-2L), ensure uniform pressure, control the temperature at 60℃, adjust the working pressure to 6Mpa, and press for 120min.

[0072] (3) Remove the sample from the medium and gently wipe the surface with absorbent paper;

[0073] (4) Record the following parameters:

[0074] a. Whether the coating exhibits blistering, peeling, or cracking;

[0075] b. Use a water permeability meter to test whether the metal plate is permeable to water.

[0076] 2. Thermal insulation test

[0077] (1) Select a 10cm×10cm metal plate, ensure that the surface is flat, clean, and free of oil and dust, and spray the aerosol coating prepared in the examples and comparative examples evenly. The spray thickness is 20μm, and allow it to dry naturally for 24 hours.

[0078] (2) Fix the metal plate so that its front side is perpendicular to the light source and the temperature measurement point on the back side is the central area. Use an infrared thermometer to test the initial temperature of the central part of the back side of the metal plate.

[0079] (3) A xenon lamp is used to provide a constant power (500W / m). 2 To simulate sunlight exposure;

[0080] (4) The temperatures were then recorded after irradiation for 0, 10, 20, 30, and 60 minutes, respectively. IV. Test Results of Examples and Comparative Examples The water resistance test results of examples and comparative examples are shown in Tables 3 and 4:

[0081] Table 3 shows the water resistance test results of the examples.

[0082]

[0083] Table 4. Water resistance test results of the comparative examples

[0084]

[0085] Table 5. Thermal insulation test results of the examples and comparative examples.

[0086]

[0087]

[0088] As shown in Tables 3-4, the aerosol coatings prepared in Examples 1-9 exhibit good water resistance, with adhesion rating of 0 before and after immersion in water. No blistering, peeling, cracking, or water permeability was observed when treated at 60°C. Example 4 further optimized the mass ratio of polyvinylidene fluoride (PVDF) to dimethyl 3,3'-dithiodipropionate to 2:1, resulting in more uniform dispersion of PVDF in the coating and the formation of a more complete hydrophobic network. Furthermore, it further reduced the thermal conductivity and improved the coating's heat insulation capability.

[0089] Comparative Example 1 did not contain polyvinylidene fluoride (PVDF), Comparative Example 2 contained excessive PVDF, Comparative Example 3 did not contain dimethyl 3,3′-dithiodipropionate (DMD), and Comparative Example 4 contained excessive DMD. These results in reduced coating adhesion, exhibiting varying degrees of bubbling, peeling, cracking, and water permeability, thus reducing water resistance. Comparative Examples 5 and 6 either did not contain transesterification inhibitors or contained excessive amounts, resulting in minimal impact on water resistance.

[0090] As shown in Table 5, the aerosol coatings prepared in Examples 1-9 exhibited a reduced temperature change trend at the center of the back of the metal plate after irradiation with a simulated light source, demonstrating good heat insulation and stability. After 60 minutes of irradiation, the temperature stabilized between 105 and 113°C. In Comparative Examples 1-6, the temperature change trend was significant after 10 minutes of irradiation with a simulated light source, and the temperatures after 30 minutes were all higher than those in Examples 1-9. After 60 minutes of irradiation, the temperatures stabilized between 135 and 148°C, significantly higher than the constant temperature of the examples.

[0091] The above results indicate that the aerosol coating prepared in this embodiment has both excellent water resistance and thermal insulation properties.

[0092] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A waterproof and heat-insulating aerosol coating, characterized in that, Based on parts by weight, it comprises the following components: The transesterification inhibitor is any one of triphenyl phosphite, sodium acid pyrophosphate, and sodium dihydrogen phosphate. The mass ratio of polyvinylidene fluoride to dimethyl 3,3'-dithiodipropionate is (0.8-3):

1.

2. The waterproof and heat-insulating aerosol coating according to claim 1, characterized in that, The solvent is a mixture of ester solvents and alcohol solvents or a mixture of ester solvents and ketone solvents.

3. The waterproof and heat-insulating aerosol coating according to claim 1, characterized in that, The propellant is at least one selected from propane, butane, 1,1,1,2-tetrafluoroethane, and dimethyl ether.

4. The waterproof and heat-insulating aerosol coating according to claim 1, characterized in that, The dispersant is a multifunctional amine dispersant, a carboxylate dispersant, or a polyethyleneimine derivative dispersant.

5. The waterproof and heat-insulating aerosol coating according to claim 1, characterized in that, The pigment is selected from either inorganic or organic pigments.

6. The waterproof and heat-insulating aerosol coating according to claim 1, characterized in that, The polyvinylidene fluoride has a D50 particle size of 0.5–1 μm; the pigment has a D50 particle size of 1–3 μm.

7. The method for preparing the waterproof and heat-insulating aerosol coating according to any one of claims 1 to 6, characterized in that, The steps include: S1: Weigh each component according to the weight parts, add pigment to the dispersant and solvent, and disperse in a high-speed disperser until uniform; S2: Add polydimethylsiloxane, polyvinylidene fluoride, dimethyl 3,3'-dithiodipropionate and transesterification inhibitor to the solvent, and stir and mix at 500-1000 rpm to obtain the coating mixture; S3: In a closed system, the coating mixture described in S2 is filtered and filled into an aerosol can, an aerosol valve is installed, the can is sealed, a propellant is added, and an atomizing nozzle is installed to produce a waterproof and heat-insulating aerosol coating.

8. The application of the waterproof and heat-insulating aerosol coating according to any one of claims 1 to 6 in the coating of outdoor buildings, ship surfaces or chassis.

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