A high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres and its preparation method

Abstract

The present invention discloses a high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres and a preparation method thereof, belonging to the field of functional coating technology. The present invention modifies the hollow glass microspheres by using an alkaline solution and a composite coupling agent solution, thereby effectively improving the dispersion uniformity of the hollow glass microspheres in the coating matrix, thereby improving the performance consistency of the coating, significantly improving the corrosion resistance and long-term stability of the coating in a highly corrosive environment, balancing the heat insulation, corrosion resistance, weather resistance and mechanical properties of the coating, enabling it to adapt to long-term use requirements in extremely complex environments, and also solving the defects of bulging, cracking and falling off caused by water absorption when the humidity and temperature change, so that the performance of the coating can be guaranteed; at the same time, the modified hollow glass microspheres can work together with the resin matrix to form a uniform and dense coating structure, providing an excellent physical barrier effect, thereby enhancing the overall protective ability of the coating and improving the heat insulation performance of the coating.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional coatings, and in particular relates to a high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres and a preparation method thereof. Background Art

[0002] Energy consumption in metal equipment remains a core concern, especially in summer, when intense solar radiation can cause metal surface temperatures to soar to 70-80°C. This not only increases energy consumption but also leads to a host of other issues, including increased cooling requirements, increased thermal stress on materials, and decreased insulation performance. Current technologies typically use spray systems to cool metal equipment, but this approach consumes significant amounts of water and energy and fails to fundamentally address the problem.

[0003] In contrast, thermal insulation coatings are a more ideal solution due to their excellent thermal insulation properties, simple construction methods, high cost-effectiveness and wide applicability. By combining functional fillers with a polymer matrix, thermal insulation coatings can effectively reflect most of the solar radiation, reduce the surface temperature of objects, and provide good sealing and corrosion protection. In the petrochemical industry, the application of thermal insulation coatings can significantly reduce the use of spray water, reduce operating costs and extend the service life of equipment; in the construction field, thermal insulation coatings can effectively reduce indoor temperatures and reduce the frequency of air conditioning use, thereby achieving the goal of energy conservation and consumption reduction. Therefore, the development of high-performance thermal insulation coatings can not only address the problem of energy consumption in high-temperature environments, but also provide long-term protection for industrial equipment and building structures, which has important economic and social value.

[0004] Hollow glass microspheres, a novel inorganic material with a unique structure, have become a research focus in the field of thermal insulation and anti-corrosion coatings due to their low density, low thermal conductivity, high strength, and excellent chemical stability. Their hollow interior not only imparts extremely low thermal conductivity but also significantly reduces the overall density of the coating, providing new insights into the development of lightweight, efficient thermal insulation and anti-corrosion coatings.

[0005] In recent years, with advances in nanotechnology and composite material preparation processes, composite coatings based on hollow glass microspheres have made significant progress in optimizing performance and expanding their applications. By combining hollow glass microspheres with high-performance resin matrices, functional fillers, and advanced interface modification techniques, researchers have successfully developed a series of novel coating materials. These materials not only demonstrate broad application prospects in traditional fields such as petrochemicals, construction, and shipbuilding, but also show great potential in emerging fields such as aerospace and new energy. With the continuous improvement of material performance requirements and the continuous optimization of preparation processes, high-efficiency thermal insulation and anti-corrosion composite coatings based on hollow glass microspheres are bound to become one of the important directions for the future development of coating materials.

[0006] However, although hollow glass microspheres have shown great potential in the field of thermal insulation and anti-corrosion coatings, they still face many challenges in practical applications. First, the problem of the uniformity of the dispersion of hollow microspheres in the coating matrix has not been effectively solved, which directly affects the overall performance stability of the coating. Secondly, the existing technology has not fundamentally solved the problem of long-term corrosion resistance of composite coatings based on hollow glass microspheres in highly corrosive environments (such as seawater), resulting in a significant decrease in the performance of the coating when exposed to corrosive media for a long time. In addition, there are still technical bottlenecks in the balance optimization between the thermal insulation performance, anti-corrosion performance, weather resistance and mechanical properties of the coating, making it difficult to meet the use requirements under multiple harsh working conditions at the same time. For example, in the marine environment, the coating not only needs to withstand long-term erosion by seawater, but also has to cope with multiple challenges such as temperature changes, ultraviolet radiation and mechanical shock, which puts higher requirements on the comprehensive performance of the coating.

[0007] Therefore, how to improve the corrosion resistance and long-term stability of composite coatings based on hollow glass microspheres in highly corrosive environments has become a technical problem that needs to be urgently solved in this field. Summary of the Invention

[0008] In order to solve the above technical problems, the present invention proposes a high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres and a preparation method thereof.

[0009] To achieve the above objectives, the present invention provides the following technical solutions:

[0010] A first aspect of the present invention provides a modification method for modified hollow glass microspheres, comprising: soaking the hollow glass microspheres in an alkaline solution to obtain pretreated hollow glass microspheres; dispersing the pretreated hollow glass microspheres in a composite coupling agent solution to obtain the modified hollow glass microspheres; the composite coupling agent in the composite coupling agent solution is sodium methylsiliconate and a silane coupling agent.

[0011] Technical principle: The present invention modifies hollow glass microspheres with an alkaline solution and a composite coupling agent solution, effectively improving the dispersion uniformity of the hollow glass microspheres in the coating matrix, thereby improving the performance consistency of the coating, significantly improving the corrosion resistance and long-term stability of the coating in highly corrosive environments, and balancing the thermal insulation, corrosion resistance, weather resistance and mechanical properties of the coating, enabling it to adapt to long-term use requirements in extremely complex environments. It also solves the defects of bulging, cracking and falling off caused by water absorption when the humidity and temperature change, so that the performance of the coating can be guaranteed.

[0012] Furthermore, the mass ratio of the hollow glass microspheres to the alkaline solution is 1:25; the mass fraction of the alkaline solution is 0.01%; and the alkaline solution is selected from one or more of ammonia water, calcium hydroxide solution, and sodium hydroxide solution.

[0013] Furthermore, the soaking temperature of the alkaline solution is 45-55° C., and the soaking time is 2 hours.

[0014] Furthermore, the mass concentration of the composite coupling agent in the composite coupling agent solution is 2%; the mass ratio of the sodium methylsiliconate and the silane coupling agent is 1:2; the pH value of the composite coupling agent solution is 8-9; and the mass ratio of the pretreated hollow glass microspheres and the composite coupling agent solution is 1:2.

[0015] The second aspect of the present invention also provides a modified hollow glass microsphere obtained by the above modification method.

[0016] The third aspect of the present invention also provides a high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres. The composite coating raw materials for preparing the composite coating include the following raw materials in parts by weight: 40-60 parts of epoxy emulsion, 10-20 parts of modified hollow glass microspheres, 10-20 parts of curing agent, 0.1-0.5 parts of dispersant, 0.1-0.2 parts of defoaming agent, 0.1-0.5 parts of leveling agent, 5-20 parts of glass flakes, 0-3 parts of thickener and 0-10 parts of diluent.

[0017] During the curing process of the high-efficiency thermal insulation and anti-corrosion composite coating, the modified hollow glass microspheres prepared by the present invention can work together with the resin matrix to form a uniform and dense coating structure, providing an excellent physical barrier effect, which not only helps to enhance the overall protective ability of the coating, but also helps to improve the thermal insulation performance of the coating.

[0018] Furthermore, the material of the glass flakes is borosilicate glass, and the size of the glass flakes is 80-200 mesh; the curing agent is an amine curing agent, and the amine curing agent is selected from diethylenetriamine or m-phenylenediamine; the dispersant is styrene-maleic anhydride copolymer; the defoaming agent is polyoxypropylene glycol ether; the leveling agent is polydimethylsiloxane; the thickener is sodium carboxymethyl cellulose or polyacrylamide; and the diluent is deionized water.

[0019] The fourth aspect of the present invention further provides a method for preparing the high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres according to the above technical solution, comprising the following steps:

[0020] (1) adding glass flakes, a dispersant, a defoamer, and a leveling agent to an epoxy emulsion in sequence, mixing at high speed, then adding modified hollow glass microspheres and mixing at low speed, then adding a curing agent and continuing to mix, and then adjusting the viscosity of the liquid with a thickener or a diluent to obtain a composite coating;

[0021] (2) applying the composite coating obtained in step (1) to the surface of the substrate, and curing the composite coating to obtain the high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres.

[0022] Furthermore, in step (1), the rotation speed of the high-speed mixing is 1000-2000 rpm, and the high-speed mixing time is 30 min; the rotation speed of the low-speed mixing is 200-400 rpm, and the low-speed mixing time is 10 min.

[0023] Furthermore, in step (2), the curing temperature is 5-35° C. and the relative humidity is <50%.

[0024] Compared with the prior art, the present invention has the following advantages and technical effects:

[0025] The composite coating and preparation method provided by this invention ensures uniform distribution of hollow glass microspheres within the coating matrix, effectively preventing agglomeration. This not only improves the coating's protective performance in harsh environments, particularly in highly corrosive environments like seawater, but also significantly enhances the coating's overall stability and service life. By selecting raw materials, improving the mixing process, and optimizing the coating application and curing process, the resulting composite coating offers enhanced thermal insulation and corrosion protection, providing long-term, reliable protection for metal materials in a variety of applications.

[0026] The composite coating provided by the present invention exhibits significant thermal insulation properties, effectively reducing temperature differences between the inside and outside of chemical pipelines and buildings. This enhances the material's corrosion resistance, extends its service life, reduces maintenance frequency, conserves energy, reduces environmental pollution, and helps lower manufacturing costs. The composite coating provided by the present invention not only excels in thermal insulation and corrosion resistance but also offers economic and environmental benefits to users, making it a high-performance, cost-effective, and high-quality coating material.

[0027] The present invention uses low-cost, widely available raw materials, is easy to industrialize, and has good product stability. It is simple and convenient to construct, has strong adaptability, and is suitable for various coating processes on surfaces of different shapes and sizes. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0029] Figure 1 Graphs showing the apparent thermal conductivity of the composite coatings in Example 1, Examples 4-5, and Comparative Examples 1-2;

[0030] Figure 2 The cross-hatch adhesion test results of the high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres in Example 1 are shown;

[0031] Figure 3The leveling test results of the high-efficiency heat-insulating and anti-corrosion composite coatings based on hollow glass microspheres in Examples 1-5 and Comparative Example 1 are shown;

[0032] Figure 4 The flexibility test results of the high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres in Example 1;

[0033] Figure 5 The impact resistance test results of the high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres in Example 1 are as follows;

[0034] Figure 6 This is the salt spray resistance test result of the high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres in Example 1. DETAILED DESCRIPTION

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0036] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] An embodiment of the present invention provides a modification method for modified hollow glass microspheres, comprising: soaking the hollow glass microspheres in an alkaline solution to obtain pretreated hollow glass microspheres; dispersing the pretreated hollow glass microspheres in a composite coupling agent solution to obtain the modified hollow glass microspheres; the composite coupling agent in the composite coupling agent solution is sodium methylsiliconate and a silane coupling agent.

[0038] In a preferred embodiment, the mass ratio of the hollow glass microspheres to the alkaline solution is 1:25; the mass fraction of the alkaline solution is 0.01%; and the alkaline solution is selected from one or more of aqueous ammonia, calcium hydroxide solution, and sodium hydroxide solution. The present invention pre-treats the hollow glass microspheres with the alkaline solution, thereby improving the dispersibility of the hollow glass microspheres in the matrix.

[0039] In a preferred embodiment, the average particle size of the hollow glass microspheres is 10-90 μm, and the thermal conductivity is 0.05-0.06 [W / (m·K)].

[0040] In a preferred embodiment, the soaking temperature of the alkaline solution is 45-55° C., and the soaking time is 2 hours.

[0041] In a preferred embodiment, the step of soaking the hollow glass microspheres in an alkaline solution further includes filtering, washing, and drying. The present invention has no particular limitation on the filtering, washing, and drying operations, and conventional methods in the art can be used.

[0042] In a preferred embodiment, the mass concentration of the composite coupling agent in the composite coupling agent solution is 2%; the mass ratio of the sodium methylsiliconate to the silane coupling agent is 1:2; and the pH value of the composite coupling agent solution is 8-9. By modifying hollow glass microspheres with a composite coupling agent and adding the modified hollow glass microspheres as fillers to the coating, the present invention solves the coating's problems of bulging, cracking, and shedding due to water absorption during humidity and temperature fluctuations, thereby ensuring the coating's thermal insulation properties.

[0043] In a preferred embodiment, the silane coupling agent is selected from 3-aminopropyltriethoxysilane (APTES).

[0044] In a preferred embodiment, the solvent of the composite coupling agent solution is anhydrous ethanol.

[0045] In a preferred embodiment, the reagent for adjusting the pH value of the composite coupling agent solution is a saturated sodium hydroxide solution.

[0046] In a preferred embodiment, the mass ratio of the pretreated hollow glass microspheres to the composite coupling agent solution is 1:2. Controlling the mass ratio of the pretreated hollow glass microspheres to the composite coupling agent solution within the aforementioned range facilitates improving the uniformity of the dispersion of the hollow glass microspheres in the coating matrix, thereby enhancing the coating's impermeability, corrosion resistance, and long-term stability in highly corrosive environments (such as seawater).

[0047] In a preferred embodiment, the process further comprises stirring, centrifuging, and drying after dispersing the pretreated hollow glass microspheres in the composite coupling agent solution; the stirring speed is 400-600 rpm, and the stirring time is 30 minutes. The present invention does not specifically limit the centrifugation and drying operations; conventional methods in the art may be employed.

[0048] An embodiment of the present invention also provides a high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres. The composite coating for preparing the composite coating includes the following raw materials in parts by weight: 40-60 parts of epoxy emulsion, 10-20 parts of modified hollow glass microspheres, 10-20 parts of curing agent, 0.1-0.5 parts of dispersant, 0.1-0.2 parts of defoaming agent, 0.1-0.5 parts of leveling agent, 5-20 parts of glass flakes, 0-3 parts of thickener and 0-10 parts of diluent.

[0049] In a preferred embodiment, the composite coating comprises 40-60 parts by weight, more preferably 50-60 parts by weight, of an epoxy emulsion, preferably a water-based epoxy emulsion. The present invention utilizes an epoxy emulsion as a film-forming substance, allowing for a curing process without the need for heating, simplifying application. The resulting composite coating can be used in applications not suitable for high-temperature processing, such as large structures or on-site repairs.

[0050] In a preferred embodiment, the composite coating for preparing the composite coating comprises 10-20 parts by weight of the modified hollow glass microspheres.

[0051] In a preferred embodiment, the composite coating for preparing the composite coating includes 10-20 parts of a curing agent, more preferably 10-15 parts, by weight; the curing agent is an amine curing agent, and the amine curing agent is selected from diethylenetriamine (DETA) or m-phenylenediamine (m-PDA).

[0052] In a preferred embodiment, the composite coating for preparing the composite coating includes 0.1-0.5 parts by weight of a dispersant, more preferably 0.1-0.2 parts by weight; the dispersant is a styrene-maleic anhydride copolymer.

[0053] In a preferred embodiment, the composite coating for preparing the composite coating includes 0.1-0.2 parts by weight of a defoamer; the defoamer is polyoxypropylene glycol ether.

[0054] In a preferred embodiment, the composite coating for preparing the composite coating includes 0.1-0.5 parts by weight, more preferably 0.1-0.3 parts by weight of a leveling agent; the leveling agent is polydimethylsiloxane.

[0055] In a preferred embodiment, the composite coating comprises 5-20 parts by weight, more preferably 8-15 parts by weight, of glass flakes made of borosilicate glass, with a mesh size of 80-200. The glass flakes of the present invention can extend the corrosion path of corrosive media, providing improved impermeability and corrosion resistance.

[0056] In a preferred embodiment, the composite coating for preparing the composite coating includes 0-3 parts by weight of a thickener, more preferably 1-3 parts by weight; the thickener is sodium carboxymethyl cellulose (CMC) or polyacrylamide (PAM).

[0057] In a preferred embodiment, the composite coating material for preparing the composite coating comprises 0-10 parts by weight, more preferably 2-8 parts by weight of a diluent, wherein the diluent is deionized water. The thickener and diluent in the present invention are used to adjust the viscosity of the feed solution.

[0058] The present invention also provides a method for preparing the high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres according to the above technical solution, comprising the following steps:

[0059] (1) adding glass flakes, a dispersant, a defoamer, and a leveling agent to an epoxy emulsion in sequence, mixing at high speed, then adding modified hollow glass microspheres and mixing at low speed, then adding a curing agent and continuing to mix, and then adjusting the viscosity of the liquid with a thickener or a diluent to obtain a composite coating;

[0060] (2) applying the composite coating obtained in step (1) to the surface of the substrate, and curing the composite coating to obtain the high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres.

[0061] In a preferred embodiment, in step (1), the high-speed mixing speed is 1000-2000 rpm, and the high-speed mixing time is 30 minutes; the low-speed mixing speed is 200-400 rpm, and the low-speed mixing time is 10 minutes. The present invention ensures thorough mixing by low-speed mixing after adding the modified hollow glass microspheres without destroying the hollow glass microsphere structure.

[0062] In a preferred embodiment, in step (2), the substrate further comprises a surface treatment step before coating; the surface treatment process comprises: sequentially polishing and cleaning the substrate; the polishing comprises polishing with 800# and 3000# sandpaper in sequence; and the cleaning comprises ultrasonic cleaning with acetone and ethanol, respectively, followed by rinsing with deionized water. The present invention ensures that the substrate surface is free of oil, dust, and rust by surface treatment of the substrate. A good substrate surface is key to ensuring coating adhesion and durability.

[0063] In a preferred embodiment, in step (2), the coating method includes spraying, brushing, rolling or dipping.

[0064] In a preferred embodiment, in step (2), the curing temperature is 5-35° C. and the relative humidity is <50%.

[0065] In a preferred embodiment, in step (2), when the composite coating obtained in step (1) is applied to the surface of the substrate, a primer and a topcoat may also be applied simultaneously, and the composite coating in step (1) serves as an intermediate paint; the primer is selected from zinc-rich epoxy primer, the coating thickness is 100-160 μm, and the dry film thickness is controlled at 50-80 μm; the topcoat is selected from fluorocarbon topcoat, the coating thickness is 60-100 μm, and the dry film thickness is controlled at 30-50 μm.

[0066] The room temperature in the embodiments of the present invention refers to "25±2°C".

[0067] Unless otherwise specified, the raw materials in the examples of the present invention were purchased from commercial sources.

[0068] Example 1

[0069] A high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres, wherein the composite coating is prepared from the following raw materials in parts by weight: 60 parts of waterborne epoxy emulsion, 20 parts of modified hollow glass microspheres, 0.2 parts of styrene-maleic anhydride copolymer, 0.1 parts of polydimethylsiloxane, 0.1 parts of polyoxypropylene glycol ether, 15 parts of m-phenylenediamine, 10 parts of glass flakes, and 5 parts of deionized water;

[0070] Among them, the preparation method of the modified hollow glass microspheres is as follows: the hollow glass microspheres are immersed in a saturated calcium hydroxide solution with a mass fraction of 0.01% (diluted 10,000 times) at a mass ratio of 1:25, stirred at 50°C for 2 hours, and then filtered, washed and dried to obtain pretreated hollow glass microspheres. Sodium methylsiliconate and 3-aminopropyltriethoxysilane are mixed in a mass ratio of 1:2 and dissolved in anhydrous ethanol. The pH value of the mixed solution is adjusted to 8.5 with a saturated sodium hydroxide solution, and allowed to stand to obtain a composite coupling agent solution. The mass concentration of the composite coupling agent in the composite coupling agent solution is 2%. The pretreated hollow glass microspheres are dispersed in the above-mentioned composite coupling agent solution at a mass ratio of 1:2, stirred at a speed of 400 rpm for 30 minutes, and then centrifuged and dried to obtain modified hollow glass microspheres.

[0071] The preparation method of the high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres has the following specific steps:

[0072] (1) The Q235 substrate was polished with 800# and 3000# sandpaper in sequence, and then ultrasonically cleaned with acetone and ethanol respectively, and then rinsed with deionized water to obtain a pretreated Q235 substrate. The pretreated Q235 substrate needed to be covered with the coating within 30 minutes.

[0073] (2) 200 mesh glass flakes, styrene-maleic anhydride copolymer, polydimethylsiloxane, and polyoxypropylene glycol ether were added to the aqueous epoxy emulsion in sequence, and the mixture was mixed and dispersed at a speed of 1800 rpm for 30 min. Then, modified hollow glass microspheres were added and stirred at a speed of 300 rpm for 10 min to obtain a mixture; then, m-phenylenediamine was mixed into the above mixture and continued to be stirred until uniform. After that, deionized water was added to adjust the viscosity of the liquid to about 100 mPa·s and the mixture was fully stirred to obtain a composite coating.

[0074] (3) The composite coating obtained in step (2) is sprayed on the surface of the pretreated Q235 substrate obtained in step (1). After the spraying is completed, it is naturally cured and formed under ventilation conditions of 25° C. and a relative humidity of 35% to obtain a high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres; wherein the spraying pressure is 0.4 MPa, the distance between the spray gun nozzle and the substrate surface is 25 cm, and the spraying thickness is 100±25 μm.

[0075] Example 2

[0076] A high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres. The composite coating for preparing the composite coating is composed of the following raw materials in parts by weight: 60 parts of aqueous epoxy emulsion, 20 parts of modified hollow glass microspheres, 0.2 parts of styrene-maleic anhydride copolymer, 0.1 parts of polydimethylsiloxane, 0.1 parts of polyoxypropylene glycol ether, 15 parts of m-phenylenediamine, 15 parts of glass flakes, and 2 parts of deionized water; wherein the preparation method of the modified hollow glass microspheres is the same as that of Example 1.

[0077] The preparation method of the high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres has the following specific steps:

[0078] (1) The Q235 substrate was polished with 800# and 3000# sandpaper in sequence, and then ultrasonically cleaned with acetone and ethanol respectively, and then rinsed with deionized water to obtain a pretreated Q235 substrate. The pretreated Q235 substrate needed to be covered with the coating within 30 minutes.

[0079] (2) 200 mesh glass flakes, styrene-maleic anhydride copolymer, polydimethylsiloxane, and polyoxypropylene glycol ether were added to the water-based epoxy emulsion in sequence, and the mixture was mixed and dispersed at a speed of 1800 rpm for 30 min. Then, modified hollow glass microspheres were added and stirred at a speed of 300 rpm for 10 min to obtain a mixture; then, m-phenylenediamine was mixed into the above mixture and continued to be stirred until uniform, and then deionized water was added to adjust the viscosity of the liquid to about 200 mPa·s and fully stirred to obtain a composite coating.

[0080] (3) Using a brush, the composite coating obtained in step (2) is sprayed evenly along a straight line starting from one end of the surface of the pretreated Q235 substrate obtained in step (1). Each time the brush is applied, an angle of 45 degrees is maintained between the brush and the substrate surface. The force is applied evenly, and the thickness of the single layer is controlled to be 20-30 μm, the brushing speed is 10 cm / s, and the total thickness of the brushing is 100±25 μm. After the brushing is completed, it is naturally cured under ventilation conditions of 25°C and a relative humidity of 35%, thereby obtaining a high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres.

[0081] Example 3

[0082] The difference from Example 2 is that the amount of modified hollow glass microspheres is 10 parts, and the amount of deionized water is changed to adjust the viscosity of the feed solution to about 250 mPa·s.

[0083] Example 4

[0084] The difference from Example 1 is that the amount of modified hollow glass microspheres is 10 parts, and the amount of deionized water is changed, and the amount of deionized water is used to adjust the viscosity of the feed solution to about 100 mPa·s.

[0085] Example 5

[0086] The difference from Example 1 is that the amount of modified hollow glass microspheres is 15 parts, and the amount of deionized water is changed to adjust the viscosity of the feed solution to about 100 mPa·s.

[0087] Comparative Example 1

[0088] The difference from Example 1 is that the amount of modified hollow glass microspheres is 0 parts, and deionized water is replaced by sodium carboxymethyl cellulose. The amount of sodium carboxymethyl cellulose is such that the viscosity of the feed solution is adjusted to about 100 mPa·s.

[0089] Comparative Example 2

[0090] The difference from Example 1 is that the amount of modified hollow glass microspheres is 5 parts, and deionized water is replaced by sodium carboxymethyl cellulose. The amount of sodium carboxymethyl cellulose is such that the viscosity of the feed solution is adjusted to about 100 mPa·s.

[0091] Comparative Example 3

[0092] The difference from Example 1 is that the amount of modified hollow glass microspheres is 0 parts, the amount of glass flakes is 0 parts, and deionized water is replaced by sodium carboxymethyl cellulose, and the amount of sodium carboxymethyl cellulose is used to adjust the viscosity of the slurry to about 100 mPa·s.

[0093] Comparative Example 4

[0094] The difference from Example 1 is that the modified hollow glass microspheres are prepared by mixing sodium methylsiliconate and 3-aminopropyltriethoxysilane in a mass ratio of 1:2 and dissolving them in anhydrous ethanol. Saturated sodium hydroxide solution is then added dropwise to adjust the pH of the mixture to 8.5. The mixture is allowed to stand to obtain a composite coupling agent solution having a mass concentration of 2%. Hollow glass microspheres are dispersed in the composite coupling agent solution at a mass ratio of 1:2, stirred at 400 rpm for 30 minutes, and then centrifuged and dried to obtain modified hollow glass microspheres.

[0095] Comparative Example 5

[0096] The difference from Example 1 is that the preparation method of the modified hollow glass microspheres is as follows: the hollow glass microspheres are immersed in a saturated calcium hydroxide solution with a mass fraction of 0.01% (diluted 10,000 times) at a mass ratio of 1:20, stirred at 50°C for 2 hours, and then filtered, washed and dried to obtain modified hollow glass microspheres.

[0097] Comparative Example 6

[0098] The difference from Example 1 is that, during the preparation of the modified hollow glass microspheres, sodium methylsiliconate is replaced by sodium trimethylsiliconate.

[0099] Comparative Example 7

[0100] The difference from Example 1 is that, during the preparation of the modified hollow glass microspheres, sodium methylsiliconate and 3-aminopropyltriethoxysilane are mixed in a mass ratio of 2:1, and the rest are the same as in Example 1.

[0101] Figure 1 The apparent thermal conductivity curves of the composite coatings in Example 1, Examples 4-5 and Comparative Examples 1-2 are shown. Figure 1 It can be seen that as the amount of modified hollow glass microspheres increases, the thermal conductivity of the composite coating gradually decreases within a certain range, and the thermal insulation performance is improved. Moreover, when the amount of modified hollow glass microspheres is 15 parts by weight, the thermal insulation effect of the coating can be significantly optimized.

[0102] Figure 2 The cross-hatch adhesion test results of the high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres in Example 1 are shown in FIG. Figure 2 It can be seen that the cutting edge of the high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres in Example 1 is completely smooth, and there is no shedding within the grid.

[0103] Figure 3 The leveling test results of the high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres in Examples 1-5 and Comparative Example 1 are shown. Figure 3 It can be seen that the surface of the composite coating has no defects such as shrinkage cavities, pinholes, orange peel, silk lines, brush marks, and haze.

[0104] Figure 4 The flexibility test results of the high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres in Example 1 are as follows. Figure 4 As can be seen, the composite coating exhibits excellent flexibility, withstanding bends as small as 2mm in diameter without cracking or peeling. This exceptional flexibility makes the coating particularly effective in applications involving complex shapes and confined spaces. Whether repairing pipelines or repairing structures with irregular surfaces or hard-to-reach corners, this composite coating provides reliable protection and sealing.

[0105] Figure 5 The impact test results of the high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres in Example 1 are shown in FIG. Figure 5 It can be seen that when a 1 kg hammer is dropped freely at a distance of 30 cm in the vertical direction from the composite coating, the composite coating is not damaged, indicating that the composite coating has excellent impact resistance.

[0106] Figure 6 The salt spray resistance test results of the high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres in Example 1 are as follows. Figure 6 It can be seen that rust begins to appear at the scratches on the composite coating after 28 days, and the rust at the scratches is more obvious after 56 days.

[0107] The physical properties of the high-efficiency heat-insulating and anti-corrosion composite coatings based on hollow glass microspheres in Examples 1-5 are shown in Table 1.

[0108] Table 1 Physical properties of coatings

[0109] Coating appearance Surface drying time / h Drying time / h Pencil hardness Adhesion / (grade) Smooth and rough ＜2 ＜24 H Level 0

[0110] The physical properties of the composite coatings of Comparative Examples 1-7 are shown in Table 2.

[0111] Table 2 Physical properties of the composite coatings of Comparative Examples 1-7

[0112]

[0113] The thermal insulation properties of the composite coatings in Examples 1-5 and Comparative Examples 1-7 are shown in Table 3.

[0114] Table 3 Coating thermal insulation performance

[0115]

[0116]

[0117] The composite coatings in Examples 1-5 and Comparative Examples 1-7 were tested for corrosion resistance (water resistance, salt spray resistance). The results are shown in Table 4:

[0118] (1) Water resistance was determined according to Method A of GB / T 1733-1993 "Determination of water resistance of paint films". The Q235 substrate samples of Examples 1-3 were immersed in distilled water. After a period of time, the samples were taken out and visually observed under scattered sunlight to record whether the coating showed any abnormal phenomena such as blistering, peeling, rusting, discoloration, or loss of gloss.

[0119] (2) According to the provisions of the standard GB / T 10125-2021 "Artificial atmosphere corrosion test salt spray test", the Q235 substrate samples in Examples 1-3 were immersed in a smoke test chamber with a temperature of 35°C, a NaCl concentration of 50g / L, and a pH value of 6.5-7.2 for several days. The samples were taken out and wiped dry with filter paper. The coating was visually observed under scattered sunlight and the presence of abnormal phenomena such as blistering, peeling, and rust was recorded.

[0120] Table 4 Anticorrosion performance of coating

[0121]

[0122] As shown in Tables 1-2, the high-efficiency thermal insulation and anti-corrosion composite coating based on hollow glass microspheres provided by the present invention has a surface drying time of less than 2 hours, a through drying time of less than 24 hours, a pencil hardness of H, and an adhesion grade of 0. It exhibits excellent adhesion and rapid drying, effectively improving construction efficiency and shortening construction schedules. The pencil hardness of H indicates that the coating possesses good mechanical strength, sufficient to withstand physical wear in most operating environments. The adhesion grade of 0 indicates excellent adhesion between the coating and the substrate.

[0123] As shown in Table 3, the high-efficiency thermal insulation and anti-corrosion composite coating based on hollow glass microspheres provided by the present invention has a thermal conductivity as low as 0.1182 W / (m·K), demonstrating excellent thermal insulation performance. A comparison of Example 1, Examples 4-5, and Comparative Examples 1-2 shows that the thermal conductivity of the composite coating decreases with increasing addition of modified glass microspheres, until it levels off. A comparison of Example 1 and Example 2 shows that conventional coating methods and changes in viscosity within a certain range have little effect on the thermal insulation performance of the composite coating.

[0124] As can be seen from Table 4, the high-efficiency thermal insulation and anti-corrosion composite coating based on hollow glass microspheres provided by the present invention exhibits excellent water resistance and neutral salt spray resistance exceeding 1200 hours. Comparison of Comparative Example 1 and Comparative Example 3 shows that the addition of glass flakes significantly improves the corrosion resistance of the composite coating. Comparative Examples 5-7 modify the preparation process of the hollow glass microspheres. Although the resulting composite coatings also achieve good corrosion resistance, they are still slightly inferior to Example 1, indicating that the modification method used in Example 1 has certain advantages in improving the corrosion resistance of the material.

[0125] In summary, the present invention significantly improves the corrosion resistance and long-term stability of the composite coating in highly corrosive environments, balances the thermal insulation, corrosion resistance, weather resistance and mechanical properties of the coating, enables it to adapt to long-term use requirements in extremely complex environments, and reduces the cost of maintenance and repainting.

[0126] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for modifying hollow glass microspheres, characterized in that: Soaking hollow glass microspheres in an alkaline solution to obtain pretreated hollow glass microspheres; dispersing the pretreated hollow glass microspheres in a composite coupling agent solution to obtain the modified hollow glass microspheres; the composite coupling agent in the composite coupling agent solution is sodium methylsiliconate and a silane coupling agent; The mass ratio of the hollow glass microspheres to the alkaline solution is 1:25; the mass ratio of the sodium methylsiliconate to the silane coupling agent is 1:

2.

2. The modification method of modified hollow glass microspheres according to claim 1, characterized in that: The mass fraction of the alkaline solution is 0.01%; the alkaline solution is selected from one or more of ammonia water, calcium hydroxide solution and sodium hydroxide solution.

3. The modification method of modified hollow glass microspheres according to claim 1, characterized in that: The soaking temperature of the alkaline solution is 45-55° C., and the soaking time is 2 hours.

4. The modification method of modified hollow glass microspheres according to claim 1, characterized in that: The mass concentration of the composite coupling agent in the composite coupling agent solution is 2%; the pH value of the composite coupling agent solution is 8-9; and the mass ratio of the pretreated hollow glass microspheres to the composite coupling agent solution is 1:

2.

5. A modified hollow glass microsphere, characterized in that: The invention is prepared by the modification method according to any one of claims 1 to 4.

6. A high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres, characterized in that: The composite coating for preparing the composite coating includes the following raw materials in parts by weight: 40-60 parts of epoxy emulsion, 10-20 parts of the modified hollow glass microspheres as described in claim 5, 10-20 parts of a curing agent, 0.1-0.5 parts of a dispersant, 0.1-0.2 parts of a defoaming agent, 0.1-0.5 parts of a leveling agent, 5-20 parts of glass flakes, 0-3 parts of a thickener and 0-10 parts of a diluent.

7. The high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres according to claim 6, characterized in that: The material of the glass flakes is borosilicate glass, and the size of the glass flakes is 80-200 mesh; and / or the curing agent is an amine curing agent, and the amine curing agent is selected from diethylenetriamine or m-phenylenediamine; and / or the dispersant is styrene-maleic anhydride copolymer; and / or the defoaming agent is polyoxypropylene glycol ether; and / or the leveling agent is polydimethylsiloxane; and / or the thickener is sodium carboxymethyl cellulose or polyacrylamide; and / or the diluent is deionized water.

8. A method for preparing a high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres according to claim 6 or 7, characterized in that: The following steps are involved: (1) adding glass flakes, a dispersant, a defoamer, and a leveling agent to an epoxy emulsion in sequence, mixing at high speed, then adding modified hollow glass microspheres and mixing at low speed, then adding a curing agent and continuing to mix, and then adjusting the viscosity of the liquid with a thickener or a diluent to obtain a composite coating; (2) applying the composite coating obtained in step (1) to the surface of the substrate, and curing the composite coating to obtain the high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres.

9. The method for preparing a high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres according to claim 8, characterized in that: In step (1), the rotation speed of the high-speed mixing is 1000-2000 rpm, and the high-speed mixing time is 30 minutes; the rotation speed of the low-speed mixing is 200-400 rpm, and the low-speed mixing time is 10 minutes.

10. The method for preparing a high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres according to claim 8, characterized in that: In step (2), the curing temperature is 5-35° C. and the relative humidity is <50%.

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