Waterproof heat-insulation aerosol type coating as well as preparation method and application thereof

Abstract

The invention discloses a waterproof heat-insulation aerosol type coating and a preparation method and application thereof, and the coating comprises the following components in parts by weight: 20-30 parts of polydimethylsiloxane, 5-15 parts of polyvinylidene fluoride, 5-10 parts of dimethyl 3, 3 '-dithiodipropionate, 1-5 parts of a transesterification inhibitor, 10-15 parts of a propellant, 5-10 parts of a dispersant, 20-40 parts of a solvent and 1-15 parts of a pigment. After the coating is sprayed, a film can be quickly formed, a layer of compact waterproof barrier is constructed on the surface of a base material, moisture permeation is avoided, the waterproof performance of the coating is remarkably improved, temperature transfer can be remarkably reduced under the high-temperature exposure condition, the temperature difference between the interior and the exterior of the base material is kept, and an effective heat insulation solution is provided for industrial equipment and the surface of an automobile.

Description

Technical Field

[0001] The invention relates to the technical field of surface protection coatings, and in particular to a waterproof and heat-insulating aerosol type coating and a preparation method and application thereof. Background Art

[0002] With the continuous improvement of the requirements for surface protection of buildings, electronic equipment, automobiles, etc., the research and development and application of surface repair coatings have made significant progress. Traditional repair coatings are usually used to protect the surfaces of equipment and buildings to extend their service life, improve their aesthetics and protective performance. However, most of the surface repair coatings in the prior art focus on the optimization of a single function, such as waterproofing, anti-corrosion or heat insulation, and it is difficult to take into account multiple properties at the same time, especially in aerosol coatings, coatings with both waterproofing and heat insulation functions are still relatively scarce.

[0003] Aerosol coatings have been widely used in recent years due to their convenient spraying, uniform construction, and suitability for complex surfaces. However, the functionality of existing aerosol coatings is mainly focused on basic functions such as waterproofing and corrosion resistance, but it is difficult to take into account both waterproofing and thermal insulation properties during aerosol spraying. On the one hand, waterproof coatings usually achieve their waterproofness through hydrophobic resins (such as silicone resins, fluorocarbon resins, etc.), 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 such materials are highly hydrophilic and easily absorb moisture in a humid environment, reducing the waterproof effect and even causing the coating to fail or peel off.

[0004] In addition, the compatibility of traditional heat insulation and waterproof functions usually requires a fine ratio of multiple ingredients, and it is necessary to ensure that the film can be formed quickly and maintain a long-lasting and stable protective effect in the spray form. The characteristics of aerosol coatings, such as fast film formation time and limited coating thickness, make the stability of the composite components a major problem. At the same time, under the conditions of aerosols, the composite material needs to have an appropriate particle size and dispersibility to ensure the uniformity and stability of the spraying. Therefore, how to take into account both waterproof and heat insulation effects in existing aerosol coatings while ensuring their ease of construction and long-term performance is a problem that needs to be solved urgently in the prior art.

[0005] In summary, the development of a high-performance coating with dual functions of waterproofing and heat insulation and suitable for aerosol spraying can not only improve the versatility of surface repair coatings, but also meet the protection needs in a variety of special environments, and has broad application prospects. Summary of the invention

[0006] In view of the defects in the prior art, the present invention provides a waterproof and heat-insulating aerosol coating and a preparation method and application thereof.

[0007] The present invention provides a waterproof and heat-insulating aerosol coating, which comprises the following components in parts by weight:

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

[0009] Polyvinylidene fluoride has the characteristics of low surface energy and can form a dense hydrophobic layer, which significantly improves the waterproof performance of the coating and reduces the retention of water on the coating surface. When compounded with 3,3'-dimethyl dithiodipropionate, it can synergistically reduce the surface energy and further enhance the hydrophobicity of the coating. The strong CF bond in the molecular structure of polyvinylidene fluoride gives it extremely high thermal stability and reduces the diffusion of heat through the material. By compounding 3,3'-dimethyl dithiodipropionate with polyvinylidene fluoride, a more efficient thermal insulation barrier can be formed, which can more effectively block the transfer of heat and enhance the thermal insulation capacity 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 the coating components and improve the long-term stability of the aerosol during use, especially during storage or at different temperatures.

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

[0012] In some embodiments, the solvent is a mixed solvent of an ester solvent and an alcohol solvent or a mixed solvent of an ester solvent and a ketone solvent, preferably a mixed solvent of an ester solvent and a ketone solvent; the combined volatility characteristics of different solvents can regulate the speed of coating film formation and optimize the coating quality; among them, ester solvents and ketone solvents have strong wettability to the substrate surface, which helps the coating to adhere firmly.

[0013] In some embodiments, the propellant is at least one of 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 a triethanolamine dispersant, a dimethylethyleneamine dispersant, a quaternary ammonium salt compound (such as hexadecyltrimethylammonium chloride) dispersant; the carboxylate dispersant includes a sodium dodecylbenzenesulfonate dispersant, a sodium oleate dispersant, and a sodium laurate dispersant; the polyethyleneimine derivative dispersant includes a polyethyleneimine dispersant and a polyethyleneimine-derived quaternary ammonium salt dispersant; the dispersant can evenly disperse the solid components in the coating in the matrix material to avoid aggregation and precipitation.

[0015] In some embodiments, the pigment is selected from any one of an inorganic pigment and an organic pigment. The inorganic pigment includes carbon black, titanium white, chrome green and phthalocyanine green; and the organic pigment includes toluidine red.

[0016] In some embodiments, the D50 particle size of the polyvinylidene fluoride is 0.5 to 1 μm; the D50 particle size of the pigment is 1 to 3 μm; and the particle size test is performed using a laser particle size analyzer. The particle sizes of the polyvinylidene fluoride and the pigment can directly affect the uniformity of the coating. Small particle sizes help the coating form a uniform and dense thermal insulation layer on the surface of the substrate, reduce heat conduction and water penetration, and enhance adhesion.

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

[0018] S1: Weigh each component by weight, add pigment to dispersant and solvent, put into high-speed disperser and disperse until uniform;

[0019] S2: adding polydimethylsiloxane, polyvinylidene fluoride, dimethyl 3,3'-dithiodipropionate and an ester exchange inhibitor to the solvent, stirring and mixing at 500-1000 rpm to obtain a 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, and after sealing with an aerosol-specific sealing machine, a propellant is charged with an aerosol-specific inflator, and an atomizing nozzle is installed to produce a waterproof and heat-insulating aerosol coating.

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

[0022] The present invention also provides the use of the waterproof and heat-insulating aerosol type coating in outdoor buildings, ship surfaces or chassis coatings.

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

[0024] 1. The present invention forms a highly hydrophobic structure on the coating surface by compounding polyvinylidene fluoride with dimethyl 3,3'-dithiodipropionate, which significantly improves the waterproof performance of the coating. The coating can form a film quickly after spraying and build a dense waterproof barrier on the surface of the substrate to prevent water 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 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 automobile 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 the form of an aerosol, thereby ensuring its construction convenience and long-term use. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only embodiments of a part of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

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

[0029] 1. The sources of raw materials used in the embodiments of the present invention are as follows:

[0030] Polydimethylsiloxane: DOWSIL, DC184;

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

[0032] 3,3′-dimethyl dithiodipropionate: Bosite;

[0033] Transesterification 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, technical grade, commercially available;

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

[0037] Dispersant: hydrophilic modified copolymer carboxylate 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] 2. The preparation method of the waterproof and heat-insulating aerosol coating of Examples 1 to 7 and Comparative Examples 1 to 6 of the present invention comprises 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 jet mill, and the particle size was tested using a Partica LA-960V2;

[0043] (2) Weighing each component by weight, slowly adding the pigment to the mixed solution of the dispersant and the solvent, stirring while adding to avoid agglomeration, and dispersing the mixture at 3000 rpm using a high-speed disperser for 60 minutes until the pigment is completely dispersed to form a uniform pigment slurry;

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

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

[0046] (5) In a closed system, fill the filtered paint mixture into an aerosol can with a filling volume of 60-80% of the can volume, install an aerosol valve, seal it with an aerosol-specific sealing machine, and then fill it with propellant using an aerosol-specific inflator. The filling pressure is controlled to be less than 0.8MPa / 25°C, install the atomizing nozzle and seal it to ensure that the nozzle is not blocked and can be sprayed normally.

[0047] The proportions of the embodiments and comparative examples 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 Technical solutions of comparative examples (parts by weight)

[0053]

[0054]

[0055] 3. Performance Test Method

[0056] 1. Waterproof performance test

[0057] Adhesion test:

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

[0059] (2) Adhesion test is carried out according to GB / T9286-1998, and the results are divided into 6 levels from 0 to 5:

[0060] Level 0: There is no or very little peeling of the coating around the grid, and the adhesion is excellent.

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

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

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

[0064] Level 4: The coating peeling area is 35% to 65% of the total grid area. Most of the coating is peeled off and the exposed base material is obvious.

[0065] Level 5: The coating peeling area is greater than 65% of the total area of ​​the cross-cutting area. The coating in almost the entire cross-cutting area is completely peeled off and the substrate is completely exposed.

[0066] (3) The metal plate was completely immersed in deionized water at 60°C for 24 h;

[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 in the same manner as the adhesion test in step (2).

[0069] Water resistance test:

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

[0071] (2) Place a 10 cm × 10 cm metal plate in an autoclave (Shanghai Jinpeng Instrument ZF-2L) to ensure uniform pressure, control the temperature at 60 °C, adjust the working pressure to 6 MPa, and hold for 120 min;

[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 has blistering, peeling or cracking;

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

[0076] 2. Thermal insulation test

[0077] (1) Select a 10 cm × 10 cm metal plate, ensure that the surface is flat, clean, and free of oil and dust, and evenly spray the aerosol coating prepared in the embodiment and the comparative example to a thickness of 20 μm, and 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 center area. Use an infrared thermometer to test the initial temperature of the center part of the back side of the metal plate.

[0079] (3) Use xenon lamp to provide constant power (500W / m 2 ) to simulate sunlight;

[0080] (4) Then record the temperature after 0, 10, 20, 30, and 60 minutes of irradiation. IV. Test results of embodiments and comparative examples The water resistance test results of embodiments and comparative examples are shown in Tables 3 and 4:

[0081] Table 3 Water resistance test results of the embodiments

[0082]

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

[0084]

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

[0086]

[0087]

[0088] From the test results in Tables 3 to 4, it can be seen that the aerosol coatings prepared in Examples 1 to 9 have good water resistance, and the adhesion before and after immersion in water is all level 0. When treated at 60°C, there is no blistering, shedding, cracking, or water permeability of the coating. When Example 4 further optimizes the mass ratio of polyvinylidene fluoride to dimethyl 3,3'-dithiodipropionate to 2:1, the dispersion of polyvinylidene fluoride in the coating can be made more uniform, forming a more complete hydrophobic network. In addition, the thermal conductivity can be further reduced, and the thermal insulation capacity of the coating can be improved.

[0089] In Comparative Example 1, no polyvinylidene fluoride was added, in Comparative Example 2, too much polyvinylidene fluoride was added, in Comparative Example 3, no dimethyl dithiodipropionate was added, and in Comparative Example 4, too much dimethyl dithiodipropionate was added. The coating adhesion was reduced, and bubbles, shedding, cracking, and water permeability were present to varying degrees, and the water resistance was reduced. In Comparative Examples 5 and 6, no ester exchange inhibitor was added or too much was added, which had little effect on water resistance.

[0090] From the test results in Table 5, it can be seen that after the aerosol coatings prepared in Examples 1 to 9 were irradiated with the simulated light source, the temperature change trend of the center part of the back of the metal plate decreased, the thermal insulation and stability were good, and the temperature was stable between 105 and 113°C after irradiation for 60 minutes. In Comparative Examples 1 to 6, the temperature change trend was large after irradiation with the simulated light source for 10 minutes, and the temperature after irradiation for 30 minutes was higher than that of Examples 1 to 9. After irradiation for 60 minutes, the temperature was stable between 135 and 148°C, which was much higher than the constant temperature of the embodiments.

[0091] The above results show that the aerosol coating prepared in this example has excellent water resistance and heat 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 principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A waterproof and heat-insulating aerosol coating, characterized in that: In parts by weight, it includes the following components:

2. The waterproof and heat-insulating aerosol coating according to claim 1, characterized in that: The transesterification inhibitor is any one of triphenyl phosphite, sodium acid pyrophosphate and sodium dihydrogen phosphate.

3. The waterproof and heat-insulating aerosol coating according to claim 1, characterized in that: The mass ratio of the polyvinylidene fluoride to dimethyl 3,3'-dithiodipropionate is (0.8-3):

1.

4. The waterproof and heat-insulating aerosol coating according to claim 1, characterized in that: The solvent is a mixed solvent of an ester solvent and an alcohol solvent or a mixed solvent of an ester solvent and a ketone solvent.

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

6. 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.

7. The waterproof and heat-insulating aerosol coating according to claim 1, characterized in that: The pigment is selected from any one of inorganic pigments and organic pigments.

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

9. The method for preparing the waterproof and heat-insulating aerosol coating according to any one of claims 1 to 8, characterized in that: The steps include: S1: Weigh each component by weight, add pigment to dispersant and solvent, put into high-speed disperser and disperse until uniform; S2: adding polydimethylsiloxane, polyvinylidene fluoride, dimethyl 3,3'-dithiodipropionate and an ester exchange inhibitor to the solvent, stirring and mixing at 500-1000 rpm to obtain a coating mixture; S3: In a closed system, the coating mixture described in S2 is filtered and filled into an aerosol can, and an aerosol valve is installed. After sealing, the can is filled with a propellant, and an atomizing nozzle is installed to prepare a waterproof and heat-insulating aerosol coating.

10. Use of the waterproof and heat-insulating aerosol coating according to any one of claims 1 to 7 in outdoor building, ship surface or chassis coating.

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