Coating composition, thermal insulation coating as well as preparation method and application of thermal insulation coating

Abstract

The invention relates to a coating composition, a thermal insulation coating as well as a preparation method and application of the thermal insulation coating. The coating composition comprises the following components: acrylic resin, hollow glass beads and modified aerogel, the preparation raw materials of the modified aerogel comprise the following components: aerogel, a diisocyanate compound, polyethylene glycol, a chain extender and an emulsifier. The aerogel is modified, so that the aerogel stably exists in the water-based paint, and cracking of a coating and agglomeration of the aerogel are avoided. In addition, the anticorrosive primer matched with the paint also has good acid and alkali resistance, water resistance and salt fog resistance, and the formed coating has good impact strength.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and in particular to a coating composition, a thermal insulation coating, a method for preparing the same, and its application. Background Technology

[0002] Water-based thermal insulation coatings are widely researched and applied in the insulation of mechanical equipment, oil storage tanks, and petrochemical pipelines due to their advantages such as safety, environmental friendliness, low thermal conductivity, and processability. Hydrophobic aerogels have extremely low thermal conductivity; adding them to water-based coatings, even in small amounts, can significantly improve the thermal resistance of the coating, resulting in thermally insulating coatings. Water-based thermal insulation materials prepared with hydrophobic aerogels have low VOC content, aligning with environmental protection trends. Hydrophobic aerogels themselves are typically inorganic silica-based, non-toxic, and harmless; the combination of these two materials represents a development direction for green building materials. Hydrophobic aerogels themselves possess water-repellent properties, increasing the overall contact angle of the coating, enhancing its hydrophobic and waterproof performance, reducing water penetration, and thus indirectly improving the coating's freeze-thaw resistance, corrosion resistance, and durability.

[0003] For example, CN113773715A discloses an aerogel thermal insulation coating that can be used in the internal and external thermal insulation systems of various buildings. It has advantages such as good thermal insulation performance, high coating strength, good toughness, and resistance to cracking. CN114592354A discloses a SiO2-Al2O3 composite aerogel self-cleaning thermal insulation coating. Applying this coating to flexible fabrics not only ensures the fabric's softness but also increases the surface roughness, enhancing the fabric's hydrophobicity and thermal insulation performance. CN116535909A discloses a silica aerogel water-based coating. The cured coating not only has excellent thermal insulation performance but also good adhesion and water resistance.

[0004] However, hydrophobic aerogel nanoparticles have extremely high specific surface area and surface energy, making them prone to aggregation in aqueous systems, forming visible particles or flocs, which prevents the formation of stable and homogeneous slurries. Conventional physical stirring or simple coupling agent treatment cannot provide long-term, stable protection and compatibility.

[0005] Therefore, how to prepare a water-based thermal insulation coating with low thermal conductivity and stable performance has become an urgent problem to be solved. Summary of the Invention

[0006] To address the aforementioned technical problems, the present invention aims to provide a coating composition, a thermal insulation coating, its preparation method, and its application. The coating composition contains modified aerogel. The modified aerogel is prepared using a controllable process, provides uniform coating, and significantly improves the dispersibility of the hydrophobic aerogel in aqueous systems and its interfacial bonding with the resin matrix, exhibiting a core-shell structure. By combining the modified aerogel with hollow glass microspheres, acrylic emulsion, and other components, a water-based thermal insulation coating with low thermal conductivity and stable performance can be prepared.

[0007] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a coating composition comprising the following components: acrylic resin, hollow glass microspheres, and modified aerogel; wherein the raw materials for preparing the modified aerogel comprise the following components: aerogel, diisocyanate compound, polyethylene glycol, chain extender, and emulsifier.

[0008] In this invention, polyethylene glycol is used to modify the aerogel, and the resulting modified aerogel has a hydrophilic outer layer that can exist stably in water-based coatings, thus avoiding cracking of the coating and agglomeration of the aerogel.

[0009] Preferably, the modified aerogel is obtained through interfacial polymerization.

[0010] In this invention, interfacial polymerization is employed, which facilitates the reaction between the hydrophobic aerogel and the hydrophilic polyethylene glycol, effectively protecting the aerogel structure from damage. Interfacial polymerization occurs at the interface of two immiscible liquid phases. The aerogel and diisocyanate compound are dispersed in an organic phase (oil phase), and then this oil phase is dispersed in an aqueous phase containing polyethylene glycol and a chain extender. The polyethylene glycol, chain extender, and diisocyanate compound undergo a rapid polymerization reaction at the oil-water interface, thereby forming a dense polymer film on the surface of each aerogel particle.

[0011] Preferably, the diisocyanate compound includes any one or a combination of at least two of toluene diisocyanate, isophorone diisocyanate, or diphenylmethane diisocyanate.

[0012] Preferably, the chain extender comprises a diamine and / or a diol.

[0013] Preferably, the diamine includes any one or a combination of at least two of ethylenediamine, 1,6-hexanediamine, or 1,4-butanediamine.

[0014] Preferably, the diol includes any one or a combination of at least two of ethylene glycol, butanediol, or propylene glycol.

[0015] Preferably, the emulsifier comprises sodium dodecyl sulfate.

[0016] Preferably, the raw materials for preparing the modified aerogel include the following components by weight: 1 part aerogel, 1.5-2.5 parts diisocyanate compound (e.g., 1.6 parts, 1.8 parts, 2 parts, 2.2 parts, or 2.4 parts, etc.), 4-6 parts polyethylene glycol (e.g., 4.5 parts, 4.8 parts, 5 parts, 5.5 parts, or 5.8 parts, etc.), 1-2 parts chain extender (e.g., 1.2 parts, 1.4 parts, 1.5 parts, 1.6 parts, or 1.8 parts, etc.), and 0.1-1 part emulsifier (e.g., 0.2 parts, 0.4 parts, 0.5 parts, 0.6 parts, or 0.8 parts, etc.).

[0017] Preferably, the weight ratio of polyethylene glycol to chain extender is 6:(1-3), for example, it can be 6:1.5, 6:1.8, 6:2, 6:2.3 or 6:2.5, etc.

[0018] In this invention, a chain extender reacts with a diisocyanate compound to generate a hydrophobic polyurea / polyurethane crosslinked network. Polyethylene glycol (PEG) is a hydrophilic segment, and its terminal hydroxyl or amino groups can further react with the diisocyanate compound, embedding it into the polymer network and thus imparting hydrophilicity to the shell. PEG introduces the hydrophilic segment, while the chain extender introduces the hydrophobic segment. The amounts of both need to be maintained within specific ranges to maintain the hydrophilic-hydrophobic balance of the modified aerogel. If too much PEG is used, the hydrophilicity becomes too strong, affecting the film performance; similarly, if too much chain extender is used, there will be too much free small-molecule ammonia, also affecting the film performance.

[0019] Preferably, the method for preparing the modified aerogel includes the following steps: (1) Preparation of oil phase solution: The aerogel and diisocyanate compound are mixed in an organic solvent to obtain the oil phase solution; Preparation of the aqueous solution: The chain extender, polyethylene glycol and emulsifier are mixed in water to obtain the aqueous solution; (2) Interfacial polymerization: The oil phase solution is poured into the aqueous phase solution to carry out the interfacial polymerization reaction to obtain the modified aerogel.

[0020] In this invention, during the preparation of the oil phase solution in step (1), the aerogel particles are fully wetted and dispersed by the diisocyanate monomers, and the diisocyanate monomers are adsorbed on the surface of the aerogel (and its pore inner surface), thus achieving the anchoring of the diisocyanate compound by the aerogel. During the interfacial polymerization in step (2), the chain extender and polyethylene glycol dissolved in the aqueous phase diffuse to the oil-water interface and undergo a rapid polycondensation reaction with the diisocyanate compound adsorbed on the surface of the aerogel, forming a polyurea / polyurethane crosslinking network that wraps around the surface of the aerogel particles. The modified aerogel obtained by the above method has a hydrophilic polyethylene glycol shell and a hydrophobic aerogel core, which can avoid the aerogel from agglomerating in the aqueous phase and ensure the integrity of its structure. When applied to water-based thermal insulation coatings, a coating system with low thermal conductivity, stable storage, and not prone to cracking can be obtained.

[0021] Preferably, after the aerogel and diisocyanate compound in step (1) are mixed in an organic solvent, a post-treatment step is further included. The post-treatment method includes maintaining the absolute pressure of the mixture system at 0.02-0.1 MPa (e.g., 0.03 MPa, 0.05 MPa, 0.06 MPa, 0.08 MPa or 0.09 MPa, etc.) for 5-15 min (e.g., 6 min, 8 min, 10 min, 12 min or 14 min, etc.).

[0022] In this invention, maintaining the absolute pressure of the mixture system at a slight vacuum state of 0.02-0.1 MPa allows for a more secure anchoring of the diisocyanate compound on the aerogel surface.

[0023] Preferably, the organic solvent includes toluene.

[0024] Preferably, in step (1), the aerogel and diisocyanate compound are mixed in an organic solvent under stirring conditions. The stirring speed is 200-400 rpm (e.g., 230 rpm, 250 rpm, 300 rpm, 350 rpm, or 370 rpm, etc.), the stirring time is 20-40 min (e.g., 25 min, 28 min, 30 min, 35 min, or 38 min, etc.), and the stirring temperature is 10-30℃ (e.g., 12℃, 15℃, 20℃, 23℃, or 25℃, etc.).

[0025] Preferably, in step (2), the oil phase solution is poured into the aqueous phase solution under shear conditions, the shearing speed is 8000-12000 rpm (e.g., 8500 rpm, 9000 rpm, 10000 rpm, 11000 rpm or 11500 rpm, etc.), and the shearing time is 1-3 min (e.g., 1.5 min, 1.8 min, 2 min, 2.3 min or 2.5 min, etc.).

[0026] Preferably, the interfacial polymerization reaction in step (2) is carried out under stirring conditions, and the stirring speed is 300-500 rpm (for example, it can be 350 rpm, 370 rpm, 400 rpm, 430 rpm or 450 rpm, etc.).

[0027] Preferably, the reaction temperature of the interfacial polymerization reaction in step (2) is 20-30℃, for example, it can be 22℃, 24℃, 25℃, 26℃ or 28℃.

[0028] Preferably, the reaction time of the interfacial polymerization reaction in step (2) is 2-4 h, for example, it can be 2.5 h, 2.8 h, 3 h, 3.2 h or 3.5 h.

[0029] Preferably, the interfacial polymerization reaction in step (2) further includes a post-processing step, wherein the post-processing method includes solid-liquid separation, washing and drying performed sequentially.

[0030] Preferably, the solid-liquid separation includes filtration and / or centrifugation.

[0031] Preferably, the drying is vacuum drying.

[0032] Preferably, the drying temperature is 50-70°C, for example, it can be 55°C, 58°C, 60°C, 63°C or 65°C.

[0033] Preferably, the drying time is 10-15 hours, for example, 11 hours, 12 hours, 12.5 hours, 13 hours or 14 hours.

[0034] Preferably, the coating composition comprises the following components by weight: 18-42 parts of acrylic resin (e.g., 20, 23, 25, 28, 30, 33, 35, or 40 parts, etc.), 7-25 parts of hollow glass microspheres (e.g., 8, 10, 12, 13, 14, 15, 16, 18, or 20 parts, etc.), and 5-20 parts of modified aerogel (e.g., 8, 9, 10, 12, 14, 15, 18, or 19 parts, etc.).

[0035] Preferably, the coating composition further comprises 15-42 parts of water, for example, 18 parts, 20 parts, 25 parts, 26 parts, 30 parts, 35 parts, 36 parts or 40 parts, etc.

[0036] Preferably, the coating composition further includes additives.

[0037] Preferably, the amount of the adjuvant is 2-10 parts by weight, for example, it can be 3 parts, 3.3 parts, 3.9 parts, 4 parts, 5 parts, 6 parts, 7 parts, 7.8 parts, 8 parts, 8.9 parts or 9 parts, etc.

[0038] Preferably, the additives include any one or a combination of at least two of the following: wetting and dispersing agents, defoamers, neutralizing agents, film-forming aids, thickeners, or bactericides.

[0039] Preferably, the wetting and dispersing agent is in the form of 1.3-4.5 parts by weight, for example, 2 parts, 2.2 parts, 2.5 parts, 3 parts, 3.5 parts, 3.6 parts, 4 parts or 4.3 parts, etc.

[0040] Preferably, the defoamer is present in a weight ratio of 0.2-0.6 parts, for example, 0.3 parts, 0.25 parts, 0.35 parts, 0.4 parts, 0.45 parts, 0.5 parts or 0.55 parts, etc.

[0041] Preferably, the neutralizing agent is present in a weight ratio of 0.1-0.45 parts, for example, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts, or 0.4 parts.

[0042] Preferably, the film-forming aid is present in parts by weight of 0.5-3.5, for example, 1 part, 1.5 parts, 2 parts, 2.5 parts or 3 parts, etc.

[0043] Preferably, the thickener is present in 0.1-1 parts by weight, for example, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts or 0.8 parts, etc.

[0044] Preferably, the bactericide is present in a weight ratio of 0.1-0.8 parts, for example, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts or 0.7 parts, etc.

[0045] Preferably, the wetting and dispersing agent includes any one or a combination of at least two of anionic carboxylate dispersants, cationic quaternary ammonium salt dispersants, or modified polymeric dispersants.

[0046] Preferably, the wetting and dispersing agent comprises any one or a combination of at least two of BYK-190 from BYK, Dispers 750W from DIGIC, or AFCONA-4560 from Evcona.

[0047] Preferably, the defoamer includes silicone-based defoamers and / or mineral defoamers.

[0048] Preferably, the neutralizing agent includes an alcohol amine neutralizing agent.

[0049] Preferably, the film-forming aid comprises any one or a combination of at least two of dodecyl alcohol ester, dipropylene glycol butyl ether, diethylene glycol butyl ether, or propylene glycol diacetate.

[0050] Preferably, the thickener includes polyurethane thickeners and / or alkaline swelling thickeners.

[0051] Preferably, the film-forming aid comprises any one or a combination of at least two of dodecyl alcohol ester, dipropylene glycol butyl ether, diethylene glycol butyl ether, or propylene glycol diacetate.

[0052] Preferably, the antibacterial agent includes any one or a combination of at least two of the following: OIT-45 from Shanghai Pengtu Antibacterial, LV-665B from Shanghai Wanhou Biotechnology, or FPD from Pulong International Trade.

[0053] Preferably, the density of the aerogel is 0.15-0.20 g / cm³. 3 For example, it could be 0.16 g / cm³. 3 0.17 g / cm 3 0.175 g / cm 3 0.18 g / cm 3 Or 0.19 g / cm 3 wait.

[0054] Preferably, the aerogel has a D90 of 100-150 μm, such as 110 μm, 120 μm, 125 μm, 130 μm or 140 μm.

[0055] Preferably, the aerogel comprises a hydrophobic aerogel.

[0056] Preferably, the aerogel comprises silica aerogel powder.

[0057] Preferably, the density of the hollow glass microspheres is 0.18-0.25 g / cm³. 3 For example, it could be 0.19 g / cm³. 3 0.20 g / cm 3 0.21 g / cm 3 0.22 g / cm 3 0.23 g / cm 3 Or 0.24 g / cm 3 wait.

[0058] Preferably, the hollow glass microspheres have a D90 of 50-120 μm, for example, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm or 110 μm.

[0059] In a second aspect, the present invention provides a method for preparing a coating composition as described in the first aspect, the method comprising the following steps: The acrylic resin, optional wetting and dispersing agent, optional defoamer, optional neutralizer, optional film-forming aid and optional bactericide are mixed in water, then modified aerogel and hollow glass microspheres are added, mixed, and finally an optional thickener is added to obtain the coating composition.

[0060] Preferably, the modified aerogel and hollow glass microspheres are added in multiple batches.

[0061] In this invention, the purpose of adding the modified aerogel and hollow glass microspheres in multiple batches is to ensure that the modified aerogel and hollow glass microspheres are mixed evenly with other components, and to ensure that the modified aerogel and hollow glass microspheres added in the previous batch have been evenly mixed before each addition.

[0062] Thirdly, the present invention provides a thermal insulation coating, wherein the raw materials for preparing the thermal insulation coating include the coating composition as described in the first aspect.

[0063] Fourthly, the present invention provides a method for preparing the thermal insulation coating as described in the third aspect, the method comprising the following steps: The coating composition is sprayed onto a substrate and heated at 50-70°C (e.g., 55°C, 58°C, 60°C, 63°C, or 65°C) for 3-7 days (e.g., 4 days, 5 days, or 6 days) to obtain the heat-insulating coating.

[0064] Fifthly, the present invention provides the application of the coating composition as described in the first aspect or the thermal insulation coating as described in the third aspect in the manufacture of mechanical equipment, oil storage tanks or petrochemical pipelines.

[0065] Preferably, the mechanical equipment includes chemical equipment.

[0066] Compared with the prior art, the present invention has at least the following beneficial effects: (1) The present invention provides a coating composition in which a self-made modified aerogel is used. The outer layer of the aerogel has a hydrophilic structure and can exist stably in water-based coatings, avoiding cracking of the coating and agglomeration of the aerogel. In addition, the anti-corrosion primer of the coating has good acid and alkali resistance, water resistance and salt spray resistance, and the resulting coating has good impact strength.

[0067] (2) The preparation method of the coating composition of the present invention has simple operation steps, can efficiently prepare products, and can realize large-scale industrial production.

[0068] (3) The coating composition of the present invention, while ensuring workability, adhesion and low thermal conductivity, has good acid and alkali resistance, water resistance, salt spray resistance and impact strength, and can adapt to different environments. It is suitable as a water-based thermal insulation coating for metal surfaces to form thermal insulation coatings, and is especially suitable for preparing thermal insulation coatings for various mechanical equipment, oil storage tanks or petrochemical pipelines, such as thermal insulation coatings for chemical equipment.

[0069] (4) The thermal insulation coating prepared by the coating composition of the present invention has an adhesion of 0.8-1.0 MPa, a thermal conductivity of 0.04-0.045 W / m·k, an acid resistance of more than 120 h, an alkali resistance of more than 72 h, a water resistance of more than 168 h, a salt spray resistance of more than 360 h, and an impact strength of 20-28 cm. Detailed Implementation

[0070] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0071] The sources of some of the raw materials used in the preparation of this invention are as follows: Waterborne acrylic resin: CAP-5036, Shanghai Showa Polymer Co., Ltd.; Wetting and dispersing agent: Evcona's AFCONA-4560; Defoamer: Commercially available silicone defoamer; Hollow glass microspheres: HS20 from Zhengzhou Shenglete Hollow Microsphere New Material Co., Ltd., with a density of 0.20 g / cm³. 3 D90 is 90 μm; Aerogel: M-series hydrophobic aerogel from Suzhou Zhongcui Nanomaterials Technology Co., Ltd., with a density of 0.18 g / cm³. 3 D90 is 120 μm; Neutralizing agent: Commercially available alcohol amine neutralizing agent; Film-forming aid: Commercially available dodecyl alcohol ester; Thickener: Commercially available polyurethane thickener; Fungicide: LV-665B from Shanghai Wanhou Biotechnology Co., Ltd.; Polyethylene glycol: purchased from BASF, brand name Pluriol® E400.

[0072] In the embodiments of this invention, all quantities are by weight.

[0073] Preparation Example 1 This preparation example provides a modified aerogel, the preparation method of which includes the following steps: (1) Preparation of oil phase solution: (S1) Add 1.0 g of hydrophobic silica aerogel powder to 50 mL of xylene solution containing 2.0 g of toluene diisocyanate (TDI); (S2) At 25°C, the mixture is mechanically stirred at 300 rpm for 30 minutes, and then a slight vacuum (0.05 MPa) is applied to the system and maintained for 10 minutes to obtain the oil phase solution.

[0074] Preparation of aqueous solutions: (S1) In another container, dissolve 1.5 g of ethylenediamine and 5.0 g of hydrophilic polyethylene glycol in 200 mL of deionized water; (S2) Add 0.5 g sodium dodecyl sulfate and stir until completely dissolved to obtain the aqueous solution.

[0075] (2) Interface aggregation: (S1) The oil phase solution is slowly poured into the aqueous phase solution under high-speed shear (10000 rpm, for 2 minutes); (S2) Transfer the mixture to a reactor with mechanical stirring and react at 25°C and 400 rpm for 3 hours. (S3) After the reaction is completed, the solid product is separated by filtration and washed three times with ethanol and deionized water alternately. The washed product is then dried in a vacuum drying oven at 60°C for 12 hours to obtain the modified aerogel.

[0076] Preparation Example 2 This preparation example provides a modified aerogel, the preparation method of which includes the following steps: (1) Preparation of oil phase solution: (S1) Add 1.0 g of hydrophobic silica aerogel powder to 50 mL of xylene solution containing 1.5 g of toluene diisocyanate (TDI); (S2) At 25°C, the mixture is mechanically stirred at 200 rpm for 30 minutes, and then a slight vacuum (0.05 MPa) is applied to the system and maintained for 10 minutes to obtain the oil phase solution.

[0077] Preparation of aqueous solutions: (S1) In another container, dissolve 1 g of ethylenediamine and 4.0 g of hydrophilic polyethylene glycol in 200 mL of deionized water; (S2) Add 0.5 g sodium dodecyl sulfate and stir until completely dissolved to obtain the aqueous solution.

[0078] (2) Interface aggregation: (S1) The oil phase solution is slowly poured into the aqueous phase solution under high-speed shear (10000 rpm, for 2 minutes); (S2) Transfer the mixture to a reactor with mechanical stirring and react at 25°C and 300 rpm for 2 hours. (S3) After the reaction is completed, the solid product is separated by filtration and washed three times with ethanol and deionized water alternately. The washed product is then dried in a vacuum drying oven at 60°C for 12 hours to obtain the modified aerogel.

[0079] Preparation Example 3 This preparation example provides a modified aerogel, the preparation method of which includes the following steps: (1) Preparation of oil phase solution: (S1) Add 1.0 g of hydrophobic silica aerogel powder to 50 mL of xylene solution containing 2.5 g of toluene diisocyanate (TDI); (S2) At 25°C, the mixture is mechanically stirred at 400 rpm for 30 minutes, and then a slight vacuum (0.05 MPa) is applied to the system and maintained for 10 minutes to obtain the oil phase solution.

[0080] Preparation of aqueous solutions: (S1) In another container, dissolve 2 g of ethylenediamine and 6.0 g of hydrophilic polyethylene glycol in 200 mL of deionized water; (S2) Add 0.5 g sodium dodecyl sulfate and stir until completely dissolved to obtain the aqueous solution.

[0081] (2) Interface aggregation: (S1) The oil phase solution is slowly poured into the aqueous phase solution under high-speed shear (10000 rpm, for 2 minutes); (S2) Transfer the mixture to a reactor with mechanical stirring and react at 25°C and 500 rpm for 4 hours. (S3) After the reaction is completed, the solid product is separated by filtration and washed three times with ethanol and deionized water alternately. The washed product is then dried in a vacuum drying oven at 60°C for 12 hours to obtain the modified aerogel.

[0082] Comparative Preparation Example 1 This comparative preparation example provides a modified aerogel, which differs from Preparation Example 1 only in that the amount of ethylenediamine used in step (1) of preparing the aqueous solution is 0 g.

[0083] Comparative Preparation Example 2 This comparative preparation example provides a modified aerogel, which differs from preparation example 1 only in that the amount of hydrophilic polyethylene glycol used in the preparation of the aqueous phase solution in step (1) is 0 g.

[0084] Example 1 This embodiment provides a coating composition, the preparation method of which includes the following steps: 20 parts of waterborne acrylic resin, 2 parts of wetting and dispersing agent, 0.3 parts of defoamer, 1 part of film-forming aid, 0.2 parts of bactericide and 0.2 parts of neutralizer were mixed evenly in 20 parts of water. Then, 5 parts of modified aerogel (from Preparation Example 1) and 5 parts of hollow glass microspheres were added and mixed evenly. Then, 5 parts of modified aerogel (from Preparation Example 1) and 5 parts of hollow glass microspheres were added again. Finally, 0.5 parts of thickener were added to obtain the coating composition.

[0085] Example 2 This embodiment provides a coating composition, the preparation method of which includes the following steps: 30 parts of waterborne acrylic resin, 3 parts of wetting and dispersing agent, 0.4 parts of defoamer, 2 parts of film-forming aid, 0.5 parts of bactericide and 0.3 parts of neutralizer were mixed evenly in 30 parts of water. Then, 7 parts of modified aerogel (from Preparation Example 2) and 8 parts of hollow glass microspheres were added and mixed evenly. Then, 8 parts of modified aerogel (from Preparation Example 2) and 7 parts of hollow glass microspheres were added again. Finally, 0.2 parts of thickener were added to obtain the coating composition.

[0086] Example 3 This embodiment provides a coating composition, the preparation method of which includes the following steps: 40 parts of waterborne acrylic resin, 4 parts of wetting and dispersing agent, 0.5 parts of defoamer, 3 parts of film-forming aid, 0.7 parts of bactericide and 0.4 parts of neutralizer were mixed evenly in 40 parts of water. Then, 10 parts of modified aerogel (from Preparation Example 3) and 10 parts of hollow glass microspheres were added and mixed evenly. Then, another 10 parts of modified aerogel (from Preparation Example 3) and 10 parts of hollow glass microspheres were added. Finally, 0.8 parts of thickener were added to obtain the coating composition.

[0087] Comparative Example 1 This comparative example provides a coating composition that differs from Example 1 only in that the modified aerogel is replaced with the same weight parts of unmodified commercially available aerogel (M-series hydrophobic aerogel from Suzhou Zhongcui Nanomaterials Technology Co., Ltd., with a density of 0.18 g / cm³). 3 (D90 is 120 μm).

[0088] Comparative Example 2 This comparative example provides a coating composition that differs from Example 1 only in that the modified aerogel from Preparation Example 1 is replaced with the same number of parts by weight of the modified aerogel from Comparative Preparation Example 1.

[0089] Comparative Example 3 This comparative example provides a coating composition that differs from Example 1 only in that the modified aerogel from Preparation Example 1 is replaced with the same number of parts by weight of the modified aerogel from Comparative Preparation Example 2.

[0090] Test methods To verify the performance and environmental adaptability of the coating compositions of the present invention, the coating compositions of each embodiment and comparative example were tested according to HG / T 5182-2017 Thermal Insulation Coatings for Petroleum and Chemical Equipment. Using an air spraying device, the coating composition was sprayed onto a sandblasted steel plate to a thickness of 1 mm. The size and thickness of the sandblasted steel plate conformed to the corresponding standard requirements. The sprayed samples were then placed in a 60°C oven and baked for 7 days before various tests were conducted.

[0091] Test Standards Storage stability: GB / T 6753.3-1986 Water resistance time: GB / T 1733-1993 The test results are shown in Table 1.

[0092] Table 1 The test results show that: (1) As can be seen from Examples 1-3, the present invention modifies the aerogel by using polyethylene glycol, and the modified aerogel has a hydrophilic structure on the outer layer, which can exist stably in water-based coatings, thus avoiding cracking of the coating and agglomeration of the aerogel.

[0093] (2) By comparing Example 1 and Comparative Example 1, it can be seen that if the hydrophobic aerogel is not modified, the acid and alkali resistance time of the thermal insulation coating made by the coating composition is shortened and the impact strength is reduced.

[0094] A comparison of Example 1 and Comparative Examples 2-3 shows that when modifying aerogels, the performance of the coating is significantly reduced if either the chain extender or polyethylene glycol is missing.

[0095] In summary, this invention modifies the aerogel, enabling it to exist stably in water-based coatings and preventing coating cracking and aerogel aggregation. Furthermore, the accompanying anti-corrosion primer exhibits excellent acid and alkali resistance, water resistance, and salt spray resistance, resulting in a coating with good impact strength.

[0096] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A coating composition, characterized in that, The coating composition comprises the following components: acrylic resin, hollow glass microspheres, and modified aerogel; The raw materials for preparing the modified aerogel include the following components: aerogel, diisocyanate compound, polyethylene glycol, chain extender and emulsifier.

2. The coating composition according to claim 1, characterized in that, The modified aerogel was obtained through interfacial polymerization; Preferably, the diisocyanate compound includes any one or a combination of at least two of toluene diisocyanate, isophorone diisocyanate, or diphenylmethane diisocyanate; Preferably, the chain extender comprises a diamine and / or a diol; Preferably, the diamine includes any one or a combination of at least two of ethylenediamine, 1,6-hexanediamine, or 1,4-butanediamine; Preferably, the diol includes any one or a combination of at least two of ethylene glycol, butanediol, or propylene glycol; Preferably, the emulsifier comprises sodium dodecyl sulfate; Preferably, the raw materials for preparing the modified aerogel include the following components by weight: 1 part aerogel, 1.5-2.5 parts diisocyanate compound, 4-6 parts polyethylene glycol, 1-2 parts chain extender, and 0.1-1 parts emulsifier; Preferably, the weight ratio of polyethylene glycol to chain extender is 6:(1-3); Preferably, the method for preparing the modified aerogel includes the following steps: (1) Preparation of oil phase solution: The aerogel and diisocyanate compound are mixed in an organic solvent to obtain the oil phase solution; Preparation of the aqueous solution: The chain extender, polyethylene glycol and emulsifier are mixed in water to obtain the aqueous solution; (2) Interfacial polymerization: The oil phase solution is poured into the aqueous phase solution to carry out the interfacial polymerization reaction to obtain the modified aerogel.

3. The coating composition according to claim 1 or 2, characterized in that, The coating composition comprises the following components by weight: 18-42 parts acrylic resin, 7-25 parts hollow glass microspheres, and 5-20 parts modified aerogel; Preferably, the coating composition further comprises 15-42 parts of water.

4. The coating composition according to any one of claims 1-3, characterized in that, The coating composition also includes additives; Preferably, the amount of the auxiliary agent is 2-10 parts by weight; Preferably, the additives include any one or a combination of at least two of the following: wetting and dispersing agents, defoamers, neutralizing agents, film-forming aids, thickeners, or bactericides; Preferably, the wetting and dispersing agent is present in an amount of 1.3-4.5 parts by weight; Preferably, the defoamer is present in an amount of 0.2-0.6 parts by weight; Preferably, the neutralizing agent is present in an amount of 0.1-0.45 parts by weight; Preferably, the film-forming aid is present in an amount of 0.5-3.5 parts by weight; Preferably, the thickener is present in an amount of 0.1-1 parts by weight; Preferably, the bactericide is present in an amount of 0.1-0.8 parts by weight; Preferably, the wetting and dispersing agent includes any one or a combination of at least two of anionic carboxylate dispersants, cationic quaternary ammonium salt dispersants, or modified polymeric dispersants; Preferably, the defoamer includes silicone-based defoamers and / or mineral defoamers; Preferably, the neutralizing agent includes an alcohol amine neutralizing agent; Preferably, the film-forming aid comprises any one or a combination of at least two of dodecyl alcohol ester, dipropylene glycol butyl ether, diethylene glycol butyl ether, or propylene glycol diacetate; Preferably, the thickener includes polyurethane thickeners and / or alkaline swelling thickeners.

5. The coating composition according to any one of claims 1-4, characterized in that, The density of the aerogel is 0.15-0.20 g / cm³. 3 ; Preferably, the aerogel has a D90 of 100-150 μm; Preferably, the aerogel comprises a hydrophobic aerogel; Preferably, the aerogel comprises silica aerogel powder.

6. The coating composition according to any one of claims 1-5, characterized in that, The density of the hollow glass microspheres is 0.18-0.25 g / cm³. 3 ; Preferably, the hollow glass microspheres have a D90 of 50-120 μm.

7. A method for preparing a coating composition according to any one of claims 1-6, characterized in that, The preparation method includes the following steps: The acrylic resin, optional wetting and dispersing agent, optional defoamer, optional neutralizer, optional film-forming aid and optional bactericide are mixed in water, then modified aerogel and hollow glass microspheres are added, mixed, and finally an optional thickener is added to obtain the coating composition.

8. A thermal insulation coating, characterized in that, The raw materials for preparing the thermal insulation coating include the coating composition as described in any one of claims 1-6.

9. A method for preparing a thermal insulation coating as described in claim 8, characterized in that, The preparation method includes the following steps: The coating composition is sprayed onto the substrate and heated at 50-70°C for 3-7 days to obtain the heat-insulating coating.

10. The application of a coating composition as described in any one of claims 1-6 or an insulating coating as described in claim 8 in the manufacture of mechanical equipment, oil storage tanks or petrochemical pipelines.

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