High-efficiency heat-insulation anti-corrosion composite coating based on hollow glass beads and preparation method of high-efficiency heat-insulation anti-corrosion composite coating

Abstract

The invention discloses a high-efficiency heat-insulation anti-corrosion composite coating based on hollow glass beads and a preparation method of the high-efficiency heat-insulation anti-corrosion composite coating, and belongs to the technical field of functional coatings. The hollow glass beads are modified by adopting the alkaline solution and the composite coupling agent solution, so that the dispersion uniformity of the hollow glass beads in a coating matrix is effectively improved, the performance consistency of the coating is improved, the corrosion resistance and long-acting stability of the coating in a high-corrosion environment are remarkably improved, and the service life of the coating is prolonged. The heat insulation, corrosion resistance, weather resistance and mechanical properties of the coating are balanced, so that the coating can adapt to long-term use requirements in extremely complex environments, the defects of swelling, cracking and falling of the coating due to water absorption when the humidity and temperature change are overcome, and the performance of the coating is ensured; meanwhile, the modified hollow glass beads can act together with a resin matrix to form a uniform and compact coating structure, and an excellent physical barrier effect is provided, so that the overall protection capability of the coating is enhanced, and the heat insulation performance of the coating is also improved.

Description

Technical Field

[0001] The 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] The energy consumption of metal equipment has always been a core issue of public concern, especially in summer, when strong solar radiation can cause the surface temperature of metal to soar to 70-80°C, which not only increases energy consumption, but also causes a series of problems, including increased refrigeration demand, increased thermal stress of materials, and decreased thermal insulation performance. In the current existing technology, in order to solve the problem of excessive temperature of metal equipment, a spray system is usually used for cooling, but this method not only consumes a lot of water resources and energy, but also fails to fundamentally solve the problem.

[0003] In contrast, thermal insulation coatings have become a more ideal solution due to their excellent thermal insulation performance, simple construction methods, high cost-effectiveness and wide applicability. By combining functional fillers with polymer matrices, thermal insulation coatings can effectively reflect most of the solar radiation, reduce the surface temperature of objects, and provide good sealing and anti-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 saving and consumption reduction. Therefore, the development of high-performance thermal insulation coatings can not only cope with 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] As a new type of inorganic material with a unique structure, hollow glass microspheres have gradually become the 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. Its internal hollow structure not only gives the material extremely low thermal conductivity, but also significantly reduces the overall density of the coating, providing a new idea for the development of lightweight and efficient thermal insulation and anti-corrosion coatings.

[0005] In recent years, with the advancement of nanotechnology and composite material preparation technology, composite coatings based on hollow glass microspheres have made significant progress in performance optimization and application expansion. By combining hollow glass microspheres with high-performance resin matrices, functional fillers and advanced interface modification technologies, researchers have successfully developed a series of new coating materials. These materials not only show 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 heat-insulating and anti-corrosion composite coatings based on hollow glass microspheres will surely become one of the important directions for the development of coating materials in the future.

[0006] However, although hollow glass microspheres show great potential in the field of thermal insulation and anti-corrosion coatings, they still face many challenges in practical applications. First, the problem of uniform dispersion of hollow microspheres in the coating matrix has not been effectively solved, which directly affects the overall performance stability of the coating. Second, the existing technologies have not fundamentally solved the long-term corrosion resistance problem of composite coatings based on hollow glass microspheres in high-corrosion environments (such as seawater), resulting in a significant decline in the coating performance when exposed to corrosive media for a long time. In addition, there are still technical bottlenecks in the balanced optimization of the thermal insulation performance, anti-corrosion performance, weather resistance, and mechanical properties of the coating, making it difficult to meet the usage requirements under multiple harsh working conditions simultaneously. For example, in the marine environment, the coating not only needs to withstand the long-term erosion of seawater but also cope with multiple challenges such as temperature changes, ultraviolet radiation, and mechanical impacts, which pose higher requirements for 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 high-corrosion environments has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0008] To solve the above technical problems, the present invention proposes an efficient thermal insulation and anti-corrosion composite coating based on hollow glass microspheres and its preparation method.

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

[0010] In the first aspect of the present invention, a modification method for modified hollow glass microspheres is provided, including: soaking the hollow glass microspheres with an alkali 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 methyl silicate and a silane coupling agent.

[0011] Technical principle: The present invention modifies the hollow glass microspheres with an alkali solution and a composite coupling agent solution, effectively improving the uniform dispersion of the hollow glass microspheres in the coating matrix, thereby enhancing the performance consistency of the coating, significantly improving the corrosion resistance and long-term stability of the coating in high-corrosion environments, balancing the thermal insulation, anti-corrosion, weather resistance, and mechanical properties of the coating, enabling it to meet the long-term usage requirements in extremely complex environments, and also solving the defects of bulging, cracking, and peeling of the coating caused by water absorption during humidity and temperature changes, ensuring the performance of the coating.

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

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

[0014] Furthermore, the mass concentration of the composite coupling agent in the composite coupling agent solution is 2%; the mass ratio of sodium methylsilanolate to silane coupling agent is 1:2; the pH value of the composite coupling agent solution is 8 - 9; the mass ratio of the pretreated hollow glass microspheres to 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 part of dispersant, 0.1 - 0.2 part of defoaming agent, 0.1 - 0.5 part 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 heat - insulating and anti - corrosion composite coating, the modified hollow glass microspheres prepared by the present invention can act 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 protection ability of the coating but also contributes to improving the heat - insulating 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 - type curing agent, and the amine - type curing agent is selected from diethylenetriamine or m - phenylenediamine; the dispersant is a styrene - maleic anhydride copolymer; the defoaming agent is polyoxypropylene propylene glycol ether; the leveling agent is polydimethylsiloxane; the thickener is sodium carboxymethylcellulose or polyacrylamide; the diluent is deionized water.

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

[0020] (1) Add glass flakes, dispersant, defoaming agent, and leveling agent to the epoxy emulsion in sequence, mix at high speed, then add the modified hollow glass microspheres and mix at low speed, then add the curing agent and continue mixing, and then adjust the viscosity of the material liquid with a thickener or diluent to obtain a composite coating;

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

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

[0023] Further, in step (2), the temperature of the curing 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 the preparation method provided by the present invention ensure that the hollow glass microspheres can be evenly distributed in the coating matrix, effectively avoiding the agglomeration phenomenon. It not only improves the protection performance of the coating in harsh environments, especially in highly corrosive environments such as seawater, but also significantly enhances the overall stability and service life of the coating. By selecting raw materials, improving the mixing process, and optimizing the coating construction and curing process, the obtained composite coating improves the high-efficiency heat insulation and anti-corrosion capabilities, providing long-term reliable protection for the application of metal materials in various scenarios.

[0026] The composite coating provided by the present invention has remarkable heat insulation performance, which can effectively reduce the temperature difference inside and outside chemical pipelines and buildings, thereby enhancing the anti-corrosion performance of the material, extending its service life, reducing the maintenance frequency, saving energy, reducing environmental pollution, and helping to reduce the manufacturing cost. The composite coating provided by the present invention not only performs excellently in heat insulation and anti-corrosion, but also brings economic and environmental benefits to users, and is a high-performance, economical and applicable high-quality coating material.

[0027] The present invention adopts raw materials with low cost and wide sources, which is easy to realize industrial production, and the product has good stability. The construction is simple and convenient, with strong adaptability, and is suitable for various coating processes on surfaces of different shapes and sizes. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0029] Figure 1 It is the apparent thermal conductivity curve graph of the composite coatings in Example 1, Examples 4 - 5 and Comparative Examples 1 - 2;

[0030] Figure 2 It is the cross-cut adhesion test result of the high-efficiency heat insulation and anti-corrosion composite coating based on hollow glass microspheres in Example 1;

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

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

[0034] Figure 6 The salt spray resistance test results of the high-efficiency heat-insulating and anti-corrosive composite coating based on hollow glass microspheres in Example 1. Detailed implementation manners

[0035] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0036] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the drawings and specific implementation manners.

[0037] The embodiment of the present invention provides a modification method for modified hollow glass microspheres, including: soaking the hollow glass microspheres in an alkali 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 methylsilanolate and a silane coupling agent.

[0038] In a preferred embodiment, the mass ratio of the hollow glass microspheres to the alkali solution is 1:25; the mass fraction of the alkali solution is 0.01%; the alkali solution is selected from one or more of ammonia water, calcium hydroxide solution, and sodium hydroxide solution. The present invention first pretreats the hollow glass microspheres with an alkali solution, which helps to improve 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 temperature for soaking in the alkali solution is 45-55 °C, and the soaking time is 2 h.

[0041] In a preferred embodiment, after soaking the hollow glass microspheres in an alkali solution, the steps of filtration, washing, and drying are further included. The present invention has no special limitation on the operations of filtration, washing, and drying, and conventional operation methods in the art can be adopted.

[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 sodium methylsilanolate to silane coupling agent is 1:2; the pH value of the composite coupling agent solution is 8 - 9. By using the composite coupling agent to modify the hollow glass microspheres and adding the modified hollow glass microspheres as fillers into the coating, the present invention solves the defects of bulging, cracking, and peeling of the coating due to water absorption during humidity and temperature changes, and ensures the heat insulation performance of the coating.

[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 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. By controlling the mass ratio of the pretreated hollow glass microspheres to the composite coupling agent solution within the above range, the present invention is beneficial to improving the dispersion uniformity of the hollow glass microspheres in the coating matrix, thereby enhancing the anti-permeability, corrosion resistance, and long-term stability of the coating in a highly corrosive environment (such as seawater).

[0047] In a preferred embodiment, after dispersing the pretreated hollow glass microspheres in the composite coupling agent solution, the steps of stirring, centrifuging, and drying are further included; the rotation speed of the stirring is 400 - 600 revolutions per minute, and the stirring time is 30 min. The present invention has no special limitation on the operations of centrifuging and drying, and conventional operation methods in the art can be adopted.

[0048] The embodiment of the present invention also provides a highly efficient heat-insulating and anti-corrosive 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 part of dispersant, 0.1 - 0.2 part of defoaming agent, 0.1 - 0.5 part of leveling agent, 5 - 20 parts of glass flakes, 0 - 3 parts of thickening agent, and 0 - 10 parts of diluent.

[0049] In a preferred embodiment, by weight parts, the composite coating material for preparing the composite coating comprises 40 - 60 parts of epoxy emulsion, more preferably 50 - 60 parts; the epoxy emulsion is a waterborne epoxy emulsion. In the present invention, the epoxy emulsion is used as the film-forming substance, and the curing process can be completed without heating, making the construction more convenient. The obtained composite coating can be used in scenarios not suitable for high-temperature treatment, such as large structural components or on-site repair work.

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

[0051] In a preferred embodiment, by weight parts, the composite coating material for preparing the composite coating comprises 10 - 20 parts of curing agent, more preferably 10 - 15 parts; 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, by weight parts, the composite coating material for preparing the composite coating comprises 0.1 - 0.5 parts of dispersant, more preferably 0.1 - 0.2 parts; the dispersant is a styrene-maleic anhydride copolymer.

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

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

[0055] In a preferred embodiment, by weight parts, the composite coating material for preparing the composite coating comprises 5 - 20 parts of glass flakes, more preferably 8 - 15 parts; the material of the glass flakes is borosilicate glass, and the size of the glass flakes is 80 - 200 mesh. The glass flakes in the present invention can extend the corrosion path of the corrosive medium and play a better role in anti-permeation and corrosion resistance.

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

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

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

[0059] (1) Sequentially add glass flakes, dispersant, defoamer, and leveling agent to the epoxy emulsion, mix at high speed, then add modified hollow glass microspheres and mix at low speed, then add a curing agent and continue mixing, and then adjust the viscosity of the liquid material with a thickening agent or diluent to obtain a composite coating;

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

[0061] In a preferred embodiment, in step (1), the rotation speed of the high-speed mixing is 1000 - 2000 revolutions per minute, and the time of the high-speed mixing is 30 min; the rotation speed of the low-speed mixing is 200 - 400 revolutions per minute, and the time of the low-speed mixing is 10 min. In the present invention, after adding the modified hollow glass microspheres, low-speed mixing is carried out to ensure thorough and uniform mixing without damaging the structure of the hollow glass microspheres.

[0062] In a preferred embodiment, in step (2), before coating the coating on the substrate, it further includes a surface treatment step; the process of the surface treatment is: sequentially grind and clean the substrate; the grinding is carried out with 800# and 3000# sandpapers in sequence; the cleaning is to ultrasonically clean with acetone and ethanol respectively first, and then rinse with deionized water. In the present invention, by performing surface treatment on the substrate, it is ensured that there is no oil stain, dust, or rust on the surface of the substrate, and a good substrate surface is the key to ensuring the adhesion and durability of the coating.

[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 coating the composite coating obtained in step (1) on the surface of the substrate, a primer and a topcoat can be coated simultaneously, and the composite coating in step (1) is used as an intermediate coat; the primer is selected from zinc-rich epoxy primer, and 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, and the coating thickness is 60 - 100 μm, and the dry film thickness is controlled at 30 - 50 μm.

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

[0067] Unless otherwise specified, the raw materials in the embodiments of the present invention are all obtained through commercial channels.

[0068] Example 1

[0069] A high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres. The composite coating material for preparing the composite coating is composed of the following raw materials in parts by weight: 60 parts of waterborne epoxy emulsion, 20 parts of modified hollow glass microspheres, 0.2 part of styrene-maleic anhydride copolymer, 0.1 part of polydimethylsiloxane, 0.1 part of polyoxypropylene propylene 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 soaked in a saturated calcium hydroxide solution (diluted 10,000 times) with a mass fraction of 0.01% according to a mass ratio of 1:25, stirred at 50 °C for 2 h, and then filtered, washed, and dried to obtain pretreated hollow glass microspheres. Sodium methyl silanolate and 3-aminopropyltriethoxysilane are mixed in a mass ratio of 1:2 and dissolved in absolute ethanol. The pH value of the mixed solution is adjusted to 8.5 using a saturated sodium hydroxide solution, and then left standing 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 composite coupling agent solution according to a mass ratio of 1:2, stirred at a rotation speed of 400 revolutions per minute for 30 min, 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 is as follows:

[0072] (1) The Q235 substrate is polished successively with 800# and 3000# sandpapers, then ultrasonically cleaned with acetone and ethanol respectively, and then rinsed with deionized water to obtain a pretreated Q235 substrate. The pretreated Q235 substrate needs to be coated within 30 min.

[0073] (2) 200-mesh glass flakes, styrene-maleic anhydride copolymer, polydimethylsiloxane, and polyoxypropylene propylene glycol ether are successively added to the waterborne epoxy emulsion, mixed and dispersed at a rotation speed of 1800 revolutions per minute for 30 min, then the modified hollow glass microspheres are added, and stirred at a rotation speed of 300 revolutions per minute for 10 min to obtain a mixture; then m-phenylenediamine is mixed into the above mixture and stirred continuously until uniform, and then deionized water is added to adjust the viscosity of the material liquid to about 100 mPa·s and stirred evenly to obtain a composite coating material.

[0074] (3) Spray the composite coating obtained in step (2) onto the surface of the pretreated Q235 substrate obtained in step (1). After spraying, cure it naturally under ventilation conditions at 25°C and a relative humidity of 35% to obtain a highly efficient heat-insulating and anticorrosive composite coating based on hollow glass microspheres. Among them, 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 highly efficient heat-insulating and anticorrosive 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 waterborne epoxy emulsion, 20 parts of modified hollow glass microspheres, 0.2 part of styrene-maleic anhydride copolymer, 0.1 part of polydimethylsiloxane, 0.1 part of polyoxypropylene propylene glycol ether, 15 parts of m-phenylenediamine, 15 parts of glass flakes, and 2 parts of deionized water. Among them, the preparation method of the modified hollow glass microspheres is the same as that in Example 1.

[0077] A preparation method of a highly efficient heat-insulating and anticorrosive composite coating based on hollow glass microspheres, the specific steps are as follows:

[0078] (1) Polish the Q235 substrate with 800# and 3000# sandpapers in sequence, then ultrasonically clean it with acetone and ethanol respectively, and then rinse it with deionized water to obtain a pretreated Q235 substrate. The pretreated Q235 substrate needs to be coated within 30 minutes.

[0079] (2) Add 200-mesh glass flakes, styrene-maleic anhydride copolymer, polydimethylsiloxane, and polyoxypropylene propylene glycol ether to the waterborne epoxy emulsion in sequence, mix and disperse at a rotation speed of 1800 revolutions per minute for 30 minutes, then add the modified hollow glass microspheres, and stir at a rotation speed of 300 revolutions per minute for 10 minutes to obtain a mixture. Subsequently, mix m-phenylenediamine into the above mixture and continue to stir until uniform, and then add deionized water to adjust the viscosity of the slurry to about 200 mPa·s and stir evenly to obtain a composite coating.

[0080] (3) Use a brush to spray and uniformly brush the composite coating obtained in step (2) starting from one end of the surface of the pretreated Q235 substrate obtained in step (1) in a straight line direction. Each time of brushing, keep the brush at a 45-degree angle with the substrate surface, apply force evenly, and control the single-layer thickness to be 20 - 30 μm, the brushing speed to be 10 cm / s, and the total brushing thickness to be 100 ± 25 μm. After brushing, cure it naturally under ventilation conditions at 25°C and a relative humidity of 35% to obtain a highly efficient heat-insulating and anticorrosive composite coating based on hollow glass microspheres.

[0081] Example 3

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

[0083] Example 4

[0084] The difference from Example 1 is that the dosage of the modified hollow glass microspheres is 10 parts, and at the same time, the dosage of deionized water is changed. The dosage of deionized water is to adjust the viscosity of the slurry to about 100 mPa·s.

[0085] Example 5

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

[0087] Comparative Example 1

[0088] The difference from Example 1 is that the dosage of the modified hollow glass microspheres is 0 part, deionized water is replaced by sodium carboxymethylcellulose, and the dosage of sodium carboxymethylcellulose is to adjust the viscosity of the slurry to about 100 mPa·s.

[0089] Comparative Example 2

[0090] The difference from Example 1 is that the dosage of the modified hollow glass microspheres is 5 parts, deionized water is replaced by sodium carboxymethylcellulose, and the dosage of sodium carboxymethylcellulose is to adjust the viscosity of the slurry to about 100 mPa·s.

[0091] Comparative Example 3

[0092] The difference from Example 1 is that the dosage of the modified hollow glass microspheres is 0 part, the dosage of glass flakes is 0 part, deionized water is replaced by sodium carboxymethylcellulose, and the dosage of sodium carboxymethylcellulose is 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 preparation method of the modified hollow glass microspheres is as follows: sodium methyl silanolate and 3-aminopropyltriethoxysilane are mixed at a mass ratio of 1:2 and dissolved in absolute ethanol. A saturated sodium hydroxide solution is added dropwise to adjust the pH value of the mixed solution to 8.5, and then it is left standing to obtain a composite coupling agent solution. The mass concentration of the composite coupling agent in the composite coupling agent solution is 2%. The hollow glass microspheres are dispersed in the above composite coupling agent solution at a mass ratio of 1:2, stirred at a speed of 400 revolutions per minute for 30 minutes, and then centrifuged and dried to obtain the 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) according to a mass ratio of 1:20, stirred at 50 °C for 2 h, and then obtained the modified hollow glass microspheres after filtration, washing and drying.

[0097] Comparative Example 6

[0098] The difference from Example 1 is that in the preparation process of the modified hollow glass microspheres, sodium methylsilanolate is replaced by sodium trimethylsilanolate.

[0099] Comparative Example 7

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

[0101] Figure 1 It is the apparent thermal conductivity curve graph of the composite coatings in Example 1, Examples 4-5 and Comparative Examples 1-2. From Figure 1 It can be seen that with the increase in the dosage of the modified hollow glass microspheres, the thermal conductivity of the composite coating gradually decreases within a certain range, and the heat preservation performance is improved. And when the dosage of the modified hollow microspheres is 15 parts by weight, the heat insulation effect of the coating can be significantly optimized.

[0102] Figure 2 It is the cross-cut adhesion test result of the high-efficiency heat-insulating and anti-corrosive composite coating based on hollow glass microspheres in Example 1. From Figure 2 It can be seen that the cutting edge of the high-efficiency heat-insulating and anti-corrosive composite coating based on hollow glass microspheres in Example 1 is completely smooth, and there is no peeling within the grid.

[0103] Figure 3 It is the leveling property test result of the high-efficiency heat-insulating and anti-corrosive composite coating based on hollow glass microspheres in Examples 1-5 and Comparative Example 1. From Figure 3 It can be seen that there are no defects such as shrinkage holes, pinholes, orange peel, silk lines, brush marks, and haze on the surface of the composite coating.

[0104] Figure 4 It is the flexibility test result of the high-efficiency heat-insulating and anti-corrosive composite coating based on hollow glass microspheres in Example 1. From Figure 4 It can be seen that the composite coating has good flexibility and can withstand bending with a diameter as low as 2 mm without cracks or peeling. This excellent flexibility makes the coating particularly outstanding in applications with complex shapes and narrow spaces. Whether it is in pipeline repair or in structural repair work with irregular surfaces or hard-to-reach corners, this composite coating can provide reliable protection and sealing effects.

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

[0106] Figure 6 Results of the salt spray resistance test of the high-efficiency heat-insulating and anti-corrosive composite coating based on hollow glass microspheres in Example 1. It can be seen from Figure 6 that rust starts to appear at the scratched area of the composite coating after 28 days, and the rust at the scratched area is more obvious after 56 days.

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

[0108] Table 1 Physical properties of the coating

[0109] Appearance of coating film Surface drying time / h Through drying time / h Pencil hardness Adhesion / (grade) Smoothness and roughness ＜2 ＜24 H Grade 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 heat insulation performance of the composite coatings in Examples 1-5 and Comparative Examples 1-7 is shown in Table 3.

[0114] Table 3 Heat insulation performance of the coating

[0115]

[0116]

[0117] The anti-corrosion performance (water resistance, salt spray resistance) of the composite coatings in Examples 1-5 and Comparative Examples 1-7 was tested, and the results are shown in Table 4:

[0118] (1) The water resistance was determined according to Method A in the Standard Test Method for Water Resistance of Paints and Varnishes GB / T 1733-1993. The Q235 substrate specimens in Examples 1-3 were immersed in distilled water, taken out after a period of time, and visually observed and recorded for any abnormal phenomena such as blistering, peeling, rusting, discoloration, and loss of gloss under diffused sunlight.

[0119] (2) According to the provisions of 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 box with a temperature of 35°C, a NaCl concentration of 50 g / 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 recorded for abnormal phenomena such as blistering, peeling, and rust.

[0120] Table 4 Anticorrosion performance of coating

[0121]

[0122] As can be seen from Table 1-2, the high-efficiency heat-insulating 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 practical drying time of less than 24 hours, a pencil hardness of H, and an adhesion grade of 0. It has excellent adhesion and fast drying characteristics, and can effectively improve construction efficiency and shorten construction period. The pencil hardness is H, indicating that the coating has good mechanical strength, which is sufficient to cope with physical wear in most use environments. The adhesion grade reaches 0, indicating that the coating has excellent bonding strength with the substrate.

[0123] As can be seen from Table 3, the thermal conductivity of the high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres provided by the present invention is as low as 0.1182W / (m·K), and has excellent heat-insulating performance. By comparing Example 1, Examples 4-5 and Comparative Examples 1-2, it can be seen that as the amount of modified glass microspheres added to the composite coating increases, the thermal conductivity decreases until it tends to be flat. By comparing Example 1 and Example 2, it can be seen that the conventional coating method and the change of viscosity within a certain range have little effect on the heat-insulating performance of the composite coating.

[0124] As can be seen from Table 4, the high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres provided by the present invention exhibits excellent water resistance, and the neutral salt spray resistance exceeds 1200h. Comparison of Comparative Example 1 and Comparative Example 3 shows that the addition of glass flakes has a significant effect on improving the corrosion resistance of the composite coating. Comparative Examples 5-7 change the preparation process of hollow glass microspheres. Although the composite coatings obtained can also obtain 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, it can be seen that the present invention significantly improves the corrosion resistance and long-term stability of the composite coating in a highly corrosive environment, 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 only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A modification method of modified hollow glass microspheres, characterized in that, The hollow glass microspheres are soaked in an alkaline solution to obtain pretreated hollow glass microspheres; the pretreated hollow glass microspheres are dispersed 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 methylsilanolate and a silane coupling agent.

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

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

4. The modification method of the modified hollow glass microspheres according to claim 1, wherein, The mass concentration of the composite coupling agent in the composite coupling agent solution is 2%; the mass ratio of sodium methylsilanolate to the silane coupling agent is 1:2; the pH value of the composite coupling agent solution is 8-9; 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, Prepared by the modification method according to any one of claims 1 to 4.

6. An efficient heat-insulating and anti-corrosion composite coating based on hollow glass microspheres, characterized in that, The composite coating material for preparing the composite coating comprises 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 curing agent, 0.1-0.5 part of dispersant, 0.1-0.2 part of defoaming agent, 0.1-0.5 part of leveling agent, 5-20 parts of glass flakes, 0-3 parts of thickener and 0-10 parts of 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 a styrene-maleic anhydride copolymer; and / or, the defoaming agent is polyoxypropylene propylene glycol ether; and / or, the leveling agent is polydimethylsiloxane; and / or, the thickener is sodium carboxymethylcellulose or polyacrylamide; and / or, the diluent is deionized water.

8. A method for preparing the high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres according to claim 6 or 7, characterized in that, Comprises the following steps: (1) Add glass flakes, dispersant, defoaming agent and leveling agent to the epoxy emulsion in sequence, mix at high speed, then add the modified hollow glass microspheres for low-speed mixing, then add the curing agent and continue mixing, and then adjust the viscosity of the material liquid with a thickener or a diluent to obtain the composite coating material; (2) Coating the composite coating material obtained in step (1) on the surface of the substrate and curing it to obtain the high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres.

9. The preparation method of the high-efficiency heat-insulating and anti-corrosion composite coating based on hollow glass microspheres according to claim 8, wherein, In step (1), the rotation speed of the high-speed mixing is 1000-2000 revolutions per minute, and the high-speed mixing time is 30 min; the rotation speed of the low-speed mixing is 200-400 revolutions per minute, and the low-speed mixing time is 10 min.

10. The preparation method of the 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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