A vacuum insulation panel with a functional aerogel coating and a method for producing the same

Abstract

The present application provides a kind of aerogel functional coating vacuum insulated panel and its preparation method, the vacuum insulated panel includes coating and panel, coating includes the following raw materials: silica aerogel powder, dispersing agent, cosolvent, thickening agent, adhesive;Adhesive is water-based polyurethane resin.Silica aerogel coating can effectively reduce the transmission of heat due to its structural properties, play the role of reducing energy consumption, because its internal structure is a large number of uniform texture nanometer hole and multi-level fractal pore microstructure, give silica aerogel excellent thermal insulation performance, this structure distribution has good effect in preventing air convection, can reduce heat radiation, heat conduction.Therefore, silica aerogel with excellent thermal insulation performance is used in thermal insulation coating, which can significantly improve the thermal insulation effect of coating film;Meanwhile, the addition of water-based polyurethane resin can also reduce the emission of VOC, so that the vacuum insulated panel meets market requirements.

Description

Technical Field

[0001] This application relates to the field of thermal insulation materials technology, and in particular to a vacuum insulation panel with an aerogel functional coating and its preparation method. Background Technology

[0002] Currently, with social development, people's requirements and emphasis on environmental protection and energy conservation are increasing. Among these, thermal insulation materials, especially vacuum insulation panels (VIP panels), are becoming increasingly widely used, particularly in home appliances and construction. This has led to continuously rising performance requirements for thermal insulation materials. Furthermore, driven by technological advancements, in special environments such as ultra-low temperature freezers and aerospace, traditional thermal insulation materials such as polyurethane foam, rock wool felt, polystyrene foam boards, and VIP panels must meet certain thickness requirements to achieve good insulation performance. However, this inevitably limits their application scenarios and conditions. Therefore, seeking environmentally friendly and sustainable thermal insulation materials is urgently needed.

[0003] Vacuum insulation panels, as a new type of insulation material, work by greatly reducing heat conduction and convection of air molecules in a vacuum environment, thus achieving extremely low thermal conductivity. Typically, vacuum insulation panels consist of a core material and a barrier membrane. The core material is generally a porous material, such as fiberglass or polystyrene foam, while the barrier membrane seals the core material and maintains the internal vacuum state.

[0004] Glass fiber has advantages such as light weight, good chemical stability, non-combustibility, and low thermal conductivity. Its fiber structure can effectively prevent heat conduction and can withstand certain pressure. Furthermore, glass fiber is relatively inexpensive, widely available, and suitable for large-scale production. In the manufacture of vacuum insulation panels, glass fiber can be made into core materials of various shapes and densities through different molding processes to meet different application requirements. However, the structural stability of glass fiber is relatively weak; under significant external forces, the fibers may shift or be damaged, affecting insulation performance. Polystyrene foam includes expanded polystyrene (EPS) and extruded polystyrene (XPS). EPS is a white foam material with a closed-cell structure, produced by heating and pre-foaming polystyrene resin granules and then molding them in a mold; XPS is made through an extrusion foaming process, resulting in a denser closed-cell structure and higher strength. Both have advantages such as light weight, low thermal conductivity, and low cost, and are widely used in building insulation. However, polystyrene foam has poor heat resistance, is prone to deformation at high temperatures, and is flammable, requiring the addition of flame retardants to improve fire resistance.

[0005] Therefore, the core material structure of vacuum insulation panels in related technologies lacks structural stability, making it impossible to guarantee both high strength and excellent thermal insulation performance simultaneously, thus failing to meet the requirements for use in special environments. Summary of the Invention

[0006] This application provides a vacuum insulation panel with an aerogel functional coating and its preparation method, in order to solve the problem that the core material of the vacuum insulation panel in the related technology has insufficient structural stability, which cannot guarantee the simultaneous existence of high strength and excellent thermal insulation performance, and does not meet the use requirements of special environments.

[0007] In a first aspect, this application provides a vacuum insulation panel with an aerogel functional coating, the vacuum insulation panel comprising a coating and a substrate, the coating comprising the following raw materials:

[0008] The composition comprises silica aerogel powder, dispersant, co-solvent, thickener, and adhesive; wherein the silica aerogel powder has a mass fraction of 12.0%–20.0%, the dispersant has a mass fraction of 0.1%–2%, the co-solvent has a mass fraction of 1%–5%, the defoamer has a mass fraction of 0.1%–0.5%, the thickener has a mass fraction of 0.2%–0.5%, the adhesive has a mass fraction of 1%–5%, and the balance is water (72%–86%); the adhesive is an aqueous polyurethane resin.

[0009] In some possible implementations, the dispersant includes one of polyacrylate, polyphosphate, and organosilicon.

[0010] In some possible implementations, the co-solvent is any one of ethanol, isopropanol, toluene, and dichloromethane.

[0011] In some possible implementations, the defoamer is one or more combinations of organosilicon and mineral oil.

[0012] In some possible implementations, the thickener is one or a combination of an associative thickener and a polyurethane-type thickener.

[0013] In some possible implementations, the thermal conductivity of the vacuum insulation plate is 1.2 to 1.8 mw / m·k.

[0014] Secondly, this application provides a method for preparing a vacuum insulation panel with the above-mentioned aerogel functional coating, the method comprising:

[0015] After adding dispersant and co-solvent to deionized water and mixing them evenly, silica aerogel powder is added to obtain a mixed solution slurry.

[0016] Aqueous polyurethane resin is added to the mixed solution slurry and stirred, and defoamer and thickener are added to obtain a spraying liquid;

[0017] The coating liquid is sprayed onto the vacuum insulation panel using a spray gun, and after standing for 10 to 30 minutes, a vacuum insulation panel with an aerogel functional coating is obtained.

[0018] In some possible implementations, the amount of the spraying liquid applied is 1000 to 5000 ml / m².

[0019] In some possible implementations, the stirring speed of the mixed solution slurry is 450 r / min to 550 r / min.

[0020] In some possible implementations, the stirring time is 1 to 3 hours.

[0021] As can be seen from the above, this application provides a vacuum insulation panel with an aerogel functional coating and its preparation method. The vacuum insulation panel includes a coating and a substrate. The coating includes the following raw materials: silica aerogel powder, dispersant, co-solvent, thickener, and adhesive; wherein the mass fraction of silica aerogel powder is 12.0%–20.0%, the mass fraction of dispersant is 0.1%–2%, the mass fraction of co-solvent is 1%–5%, the mass fraction of defoamer is 0.1%–0.5%, the mass fraction of thickener is 0.2%–0.5%, and the mass fraction of adhesive is 1%–5%; the adhesive is an aqueous polyurethane resin. Due to its inherent structural properties, silica aerogel coatings can effectively reduce heat transfer and thus reduce energy consumption. Its internal structure, consisting of numerous uniform nanopores and multi-level fractal channel microstructures, endows silica aerogel with excellent thermal insulation properties. This structural distribution is effective in preventing air convection and can reduce heat radiation and heat conduction. Therefore, using silica aerogel with excellent thermal insulation properties in thermal insulation coatings will significantly improve the thermal insulation effect of the coating film; at the same time, adding water-based polyurethane resin can also reduce VOC emissions, enabling the vacuum insulation panel to meet market requirements. Detailed Implementation

[0022] Currently, with social development, people's requirements and emphasis on environmental protection and energy conservation are increasing. Among these, thermal insulation materials, especially vacuum insulation panels (VIP panels), are becoming increasingly widely used, particularly in home appliances and construction. This has led to continuously rising performance requirements for thermal insulation materials. Furthermore, driven by technological advancements, in special environments such as ultra-low temperature freezers and aerospace, traditional thermal insulation materials such as polyurethane foam, rock wool felt, polystyrene foam boards, and VIP panels must meet certain thickness requirements to achieve good insulation performance. However, this inevitably limits their application scenarios and conditions. Therefore, seeking environmentally friendly and sustainable thermal insulation materials is urgently needed.

[0023] Vacuum insulation panels, as a new type of insulation material, work by greatly reducing heat conduction and convection of air molecules in a vacuum environment, thus achieving extremely low thermal conductivity. Typically, vacuum insulation panels consist of a core material and a barrier membrane. The core material is generally a porous material, such as fiberglass or polystyrene foam, while the barrier membrane seals the core material and maintains the internal vacuum state.

[0024] Glass fiber has advantages such as light weight, good chemical stability, non-combustibility, and low thermal conductivity. Its fiber structure can effectively prevent heat conduction and can withstand certain pressure. Furthermore, glass fiber is relatively inexpensive, widely available, and suitable for large-scale production. In the manufacture of vacuum insulation panels, glass fiber can be made into core materials of various shapes and densities through different molding processes to meet different application requirements. However, the structural stability of glass fiber is relatively weak; under significant external forces, the fibers may shift or be damaged, affecting insulation performance. Polystyrene foam includes expanded polystyrene (EPS) and extruded polystyrene (XPS). EPS is a white foam material with a closed-cell structure, produced by heating and pre-foaming polystyrene resin granules and then molding them in a mold; XPS is made through an extrusion foaming process, resulting in a denser closed-cell structure and higher strength. Both have advantages such as light weight, low thermal conductivity, and low cost, and are widely used in building insulation. However, polystyrene foam has poor heat resistance, is prone to deformation at high temperatures, and is flammable, requiring the addition of flame retardants to improve fire resistance.

[0025] Therefore, the core material structure of vacuum insulation panels in related technologies lacks structural stability, making it impossible to guarantee both high strength and excellent thermal insulation performance simultaneously, thus failing to meet the requirements for use in special environments.

[0026] Based on this, this application provides a vacuum insulation panel with an aerogel functional coating and its preparation method. Using silica aerogel as the main insulation filler and water-based polyurethane resin as the base material, a low thermal conductivity, high insulation coating is prepared by adding various functional solvents and additives. This coating is then applied to a VIP panel membrane material to produce a VIP panel with good thermal insulation performance, suitable for use in special environments and conditions such as cryogenic refrigerators. It can significantly improve the insulation effect of VIP, greatly reducing its thermal conductivity, and also has certain anti-corrosion and anti-aging functions, extending the service life of the VIP panel. Furthermore, the coating has a certain degree of adhesion, making the membrane material's folded edges more firmly bonded, avoiding the decrease in the VIP panel's insulation capacity due to edge damage. Compared with traditional folding methods, it can reduce the possibility of air leakage caused by internal wrinkles in the aluminum foil surface. In other words, the folding enhances the sealing effect of the vacuum insulation panel, thereby reducing the failure rate of the vacuum insulation panel.

[0027] In some embodiments, the vacuum insulation panel with an aerogel functional coating provided in this application includes a coating and a substrate, wherein the coating comprises the following raw materials:

[0028] The invention comprises silica (SiO2) aerogel powder, dispersant, co-solvent, thickener, and adhesive; wherein the mass fraction of silica aerogel powder is 12.0%–20.0%, the mass fraction of dispersant is 0.1%–2%, the mass fraction of co-solvent is 1%–5%, the mass fraction of defoamer is 0.1%–0.5%, the mass fraction of thickener is 0.2%–0.5%, and the mass fraction of adhesive is 1%–5%; the adhesive is an aqueous polyurethane resin.

[0029] SiO2 aerogel is a novel solid material with a three-dimensional skeletal network structure formed by the condensation of Si-O-Si bonds. It possesses characteristics such as low density, low thermal conductivity, high porosity, and high specific surface area, making it a popular functional filler in coating products. However, the insufficient mechanical properties, poor toughness, and susceptibility to breakage of bulk aerogels increase the difficulty and cost of its use. Therefore, it is usually incorporated into film-forming resins. The preparation of SiO2 aerogel coatings involves a designed formulation with the addition of dispersants and other additives. These components are first dispersed to form a slurry; then, the slurry is mixed with silicone resin, additives, defoamers, and other fillers; finally, after dispersion treatment, the coating is prepared.

[0030] Due to its inherent structural properties, SiO2 aerogel thermal insulation coatings can effectively reduce heat transfer, thereby lowering energy consumption. (The three-dimensional porous network structure increases the heat transfer pathways within the aerogel's solid framework, significantly reducing its solid-phase thermal conductivity. The internal structure, consisting of numerous uniform nanopores and hierarchical fractal microstructures, endows SiO2 aerogel with excellent thermal insulation properties. This structural distribution is also effective in preventing air convection, reducing heat radiation and conduction.) Therefore, using SiO2 aerogel, with its superior thermal insulation properties, in thermal insulation coatings will significantly improve the coating's thermal insulation effect. Furthermore, the encapsulation of SiO2 aerogel with excellent mechanical properties (due to the role of water-based resins) avoids its tendency to fracture brittlely during deformation.

[0031] SiO2 aerogel itself has an extremely low thermal conductivity, making it one of the best-performing solid materials known for its thermal insulation properties. When applied as a functional coating to traditional VIP panels, the aerogel's nanoporous structure significantly hinders heat conduction. Its extremely small pore size, smaller than the mean free path of air molecules, greatly restricts heat conduction within the pores, making it difficult for heat to transfer through the coating and thus reducing the overall thermal conductivity. Even with a decrease in vacuum level, the aerogel coating continues to function due to its excellent thermal insulation properties, compensating for the reduced insulation performance caused by the lower vacuum level and further improving the thermal insulation performance of the vacuum insulation panel. Traditional VIP panels primarily rely on the internal vacuum environment to reduce heat conduction by gas molecules to achieve insulation. The addition of the aerogel functional coating introduces a new thermal insulation mechanism. In addition to the aerogel's inherent low thermal conductivity, the coating can also, to some extent, prevent thermal radiation and convection. The porous structure of the aerogel can scatter and absorb thermal radiation, reducing radiative heat transfer; simultaneously, the coating can also, to some extent, suppress convective heat transfer between the external air and the VIP panel surface. In this way, the vacuum insulation mechanism of the traditional VIP panel and the multiple insulation mechanisms of the aerogel functional coating work together to form a more effective insulation system, which significantly improves the overall insulation performance of the vacuum insulation panel and reduces the thermal conductivity.

[0032] Waterborne polyurethane resin, acting as a carrier for aerogel, not only uniformly coats the aerogel onto the surface of the VIP panel but also possesses excellent adhesion and sealing properties. It effectively seals any minute gaps or defects that may exist in the VIP panel, preventing air from entering the vacuum layer and thus maintaining the vacuum level inside the VIP panel, further improving thermal insulation performance. Simultaneously, the coating formed by the waterborne polyurethane resin also protects the VIP panel from external environmental damage, extending its service life and ensuring long-term stability of its thermal insulation performance.

[0033] Waterborne polyurethane resins use water as a solvent, resulting in extremely low emissions of volatile organic compounds (VOCs) during production, construction, and use. In contrast, solvent-based resins typically contain large amounts of organic solvents, which pollute the atmosphere during evaporation and may harm human health, causing respiratory diseases and nervous system damage. Some waterborne polyurethane resins are biodegradable, gradually decomposing in the natural environment by microorganisms, reducing long-term environmental pollution. However, some traditional resins, such as phenolic resins and epoxy resins, are difficult to biodegrade and remain in the environment for extended periods after disposal, causing environmental pollution.

[0034] Waterborne polyurethane resin possesses excellent sealing properties, preventing outside air and moisture from entering the vacuum insulation panel and maintaining its internal vacuum level. A stable vacuum level is crucial for reducing thermal conductivity, as the vacuum environment effectively minimizes heat transfer through gases. Simultaneously, the resin coating protects the aerogel from external erosion and damage, ensuring the long-term effectiveness of its insulation performance.

[0035] Waterborne polyurethane resins possess excellent flexibility and elasticity, enabling them to form a continuous and elastic film structure within the coating. This property allows the coating to effectively disperse stress when subjected to external impacts or deformation, preventing cracking or peeling and thus improving its durability and service life.

[0036] Waterborne polyurethane resin firmly bonds the coating to the vacuum insulation panel substrate, ensuring the coating is not easily peeled off during use and improving the overall stability and durability of the vacuum insulation panel. Using water as a solvent replaces traditional organic solvents, it releases almost no organic solvents during use, reducing environmental pollution and meeting environmental protection requirements. It can be widely used in construction, home appliances, and other fields with high environmental standards. Waterborne polyurethane resin imparts good flexibility, wear resistance, and impact resistance to the vacuum insulation panel coating. This allows the vacuum insulation panel to withstand a certain degree of friction, collision, and other external forces during handling, installation, and use, making it less prone to damage and cracking.

[0037] Waterborne polyurethane resin can be applied at room temperature, making it simple and convenient to use. It is easy to coat onto the surface of vacuum insulation panels and can adapt to different construction environments and process requirements. Furthermore, its relatively fast drying speed improves production efficiency. Waterborne polyurethane resin is highly compatible with a variety of other materials and additives, and can be easily used in conjunction with silica aerogel and other functional additives to meet different performance needs. It can also be integrated with other components of vacuum insulation panels without affecting the overall insulation performance.

[0038] Waterborne polyurethane resin, acting as a carrier for aerogel, can firmly fix the aerogel to the surface of the vacuum insulation panel, forming a stable coating structure. This stable structure helps to preserve the nanoporous structure of the aerogel, ensuring the stability of its thermal insulation performance. The resin can fill any tiny gaps and defects that may exist on the surface and inside the vacuum insulation panel, reducing heat transfer channels. It can also work in conjunction with the aerogel to form a denser insulation layer, further reducing thermal conductivity.

[0039] In some embodiments, the dispersant includes one of polyacrylate, polyphosphate, and organosilicon.

[0040] When selecting a dispersant, its chemical structure and polarity must be compatible with the components of the system, such as the waterborne polyurethane resin and silica aerogel. For example, in waterborne systems, hydrophilic dispersants should be preferred. Anionic dispersants, such as polyacrylates, mix well with waterborne polyurethane resins and have good affinity for the surface of silica aerogels, effectively reducing particle surface energy and achieving uniform dispersion. The dispersant must not react chemically with other additives in the coating to avoid affecting coating performance. For example, some amine-containing dispersants may react with acidic additives, leading to system instability; therefore, a thorough understanding of the chemical properties of each component is essential when selecting a dispersant.

[0041] Dispersants must significantly reduce the surface tension of aerogel particles, making them easier to disperse in the system. Nonionic dispersants, such as polyether dispersants, can form an adsorption layer on the surface of aerogel particles through their molecular chains, reducing surface tension and preventing particle aggregation. Dispersants with good steric hindrance effects can prevent the dispersed aerogel particles from re-aggregating. For example, polymeric dispersants, with their long molecular chains, can form a thick adsorption layer on the particle surface, generating steric hindrance and keeping the particles dispersed.

[0042] Silica aerogels typically contain a large number of hydroxyl groups on their surface, exhibiting a degree of hydrophilicity. The chosen dispersant should be able to interact with these hydroxyl groups to achieve good dispersion. Silane coupling agents, with one end reacting with the hydroxyl groups on the aerogel surface and the other end compatible with the coating system, improve the dispersibility of the aerogel. If the aerogel particles are small or irregularly shaped, a more potent dispersant may be required. Hyperdispersants offer better dispersion for small-sized and irregularly shaped aerogel particles, achieving uniform particle dispersion through various mechanisms such as electrostatic repulsion and steric hindrance.

[0043] The addition of dispersants should not reduce the thermal insulation performance of aerogel functional coatings. Some dispersants may fill the pores of the aerogel, affecting its insulation effect; therefore, thermal insulation performance testing should be conducted during selection to ensure that the use of dispersants will not negatively impact thermal insulation performance. The effects of dispersants on the coating's mechanical properties, fire resistance, etc., should also be considered. For example, some dispersants may affect the coating's hardness and flexibility, or reduce its fire resistance rating; a comprehensive evaluation is needed to select a suitable dispersant.

[0044] Therefore, this application selects one of polyacrylate, polyphosphate, or organosilicon as the dispersant, taking into account the above factors.

[0045] In some embodiments, the co-solvent is any one of ethanol, isopropanol, toluene, and dichloromethane.

[0046] When selecting a cosolvent, its chemical structure and polarity should be compatible with the waterborne polyurethane resin, silica aerogel, and other formulation components. For example, for waterborne systems, cosolvents with a certain degree of hydrophilicity should be chosen, such as alcohols (ethanol, propylene glycol, etc.) or ethers (ethylene glycol butyl ether). These cosolvents are well miscible with water and waterborne polyurethane resins, and also help the aerogel disperse better in the system. The cosolvent should not react chemically with other components in the coating to avoid affecting the stability and performance of the coating. For example, some strongly acidic or strongly alkaline cosolvents may react with the functional groups in the waterborne polyurethane resin, leading to resin aggregation or hydrolysis; therefore, such cosolvents should be avoided.

[0047] One of the main functions of cosolvents is to reduce the viscosity of the coating system, thereby improving its flowability and application performance. Choosing a cosolvent that can effectively reduce the system's viscosity is crucial. Some low-boiling-point alcohol cosolvents, such as methanol and ethanol, have good diluting capabilities and can quickly reduce the coating's viscosity; however, their high volatility may have some impact on the environment and application safety. Therefore, it is necessary to select an appropriate cosolvent and its dosage based on specific circumstances. The cosolvent should be able to improve the solubility of components such as waterborne polyurethane resins and aerogels in the system, ensuring the uniformity and stability of the coating. For example, some ketone cosolvents (such as acetone and methyl ethyl ketone) have strong dissolving capabilities and can promote the dissolution and dispersion of resins and aerogels, but their volatility and safety must also be considered. Silica aerogel surfaces typically have a certain degree of hydrophilicity or hydrophobicity; the selection of the cosolvent should consider its compatibility with the aerogel surface properties. For hydrophilic aerogels, a co-solvent with strong hydrophilicity can be selected to enhance their dispersion and dissolution in the system; for hydrophobic aerogels, a co-solvent with a certain degree of hydrophobicity can be selected, such as certain ester co-solvents (ethyl acetate, butyl acetate).

[0048] The selection of co-solvents should avoid damaging the nanoporous structure of the aerogel, so as not to affect its thermal insulation and other properties. Some co-solvents with strong polarity or high solubility may penetrate into the pores of the aerogel, causing its structural collapse. Therefore, experimental verification is required to select co-solvents with minimal impact on the aerogel structure. The boiling point and volatility of the co-solvent affect the drying rate of the coating. High-boiling-point co-solvents will slow down the drying rate of the coating, while low-boiling-point co-solvents will speed up the drying rate. When selecting co-solvents, it is necessary to control the drying rate of the coating according to the construction requirements and environmental conditions to avoid problems such as excessively rapid drying leading to surface defects (such as bubbles, cracks, etc.) or excessively slow drying affecting construction efficiency. The selection of co-solvents should also consider their impact on other properties of the coating, such as hardness, flexibility, and adhesion. Some co-solvents may remain during the coating drying process, affecting the final performance of the coating. Therefore, it is necessary to select co-solvents that can completely evaporate during the drying process and have no adverse effect on the coating performance.

[0049] Therefore, the cosolvent used in this application, taking into account the above factors, is any one of ethanol, isopropanol, toluene, and dichloromethane.

[0050] In some embodiments, the defoamer is one or more combinations of organosilicon and mineral oil.

[0051] When selecting a defoamer, it is essential that it exhibits good compatibility with the waterborne polyurethane resin, silica aerogel, and other additives in the aerogel functional coating. Incompatibility between the defoamer and the system can lead to surface defects such as pinholes and fisheyes in the coating, affecting its appearance and performance. For example, for waterborne polyurethane resin systems, waterborne defoamers, such as polyether-based or silicone-based defoamers, should be preferred. The polyether segments in the molecular structure of polyether-based defoamers can interact with the polar groups in the waterborne polyurethane resin, exhibiting good compatibility. Silicone-based waterborne defoamers, through special modification treatment, can also be stably dispersed in waterborne systems and are compatible with components such as waterborne polyurethane resin and aerogel.

[0052] The main function of defoamers is to eliminate bubbles generated during coating preparation and application, and to inhibit their regeneration within a certain period. Defoamers with high efficiency and long-lasting foam suppression properties should be selected. Silicone defoamers typically have strong defoaming capabilities, quickly breaking the surface tension of bubbles and causing them to burst. Polyether-based defoamers, on the other hand, excel in foam suppression; their molecular chains form a dynamic protective film within the system, preventing bubble formation. In practical selection, a single defoamer or a combination of different types can be used, depending on the specific bubble generation situation and the required defoaming and foam suppression performance, to achieve the best results. The addition of defoamers should not negatively impact other properties of the aerogel functional coating. For example, it should not reduce the coating's thermal insulation, mechanical properties, or fire resistance. Some defoamers may migrate within the coating, affecting the adhesion between the coating and the substrate, or altering the surface gloss. Therefore, performance testing is necessary when selecting a defoamer to evaluate its impact on various coating properties. By preparing coating samples with different defoamers, tests such as thermal insulation performance, tensile strength, and fire resistance can be conducted to ensure that the selected defoamer will not adversely affect the key performance of the coating.

[0053] Considering that aerogel functional coatings may be used in different temperature environments, defoamers should have certain temperature resistance. At high temperatures, the defoamer should not decompose or lose its defoaming effect; at low temperatures, it should not solidify or thicken, affecting its dispersion and defoaming performance in the system. For aerogel functional coatings that may be used in high-temperature environments, such as thermal insulation coatings for industrial equipment, high-temperature resistant silicone defoamers can be selected; while for coatings used in normal or low-temperature environments, polyether-based defoamers may be more suitable.

[0054] Different construction processes have different requirements for defoamers. For example, when using a spraying process, the defoamer needs to have good dispersibility and low surface tension to ensure that it can quickly eliminate bubbles during spraying without affecting the atomization and uniformity of the coating. When using a scraper or trowel application process, the defoaming speed and foam suppression time of the defoamer need to be matched with the construction speed to avoid generating new bubbles during construction. When selecting a defoamer, it is essential to choose a product that meets the requirements of the specific construction process.

[0055] Therefore, the defoamer in this application combines the above factors with one or more combinations of organosilicon and mineral oil.

[0056] In some embodiments, the thickener is one or more combinations of associative thickeners and polyurethane-type thickeners.

[0057] In some embodiments, the thermal conductivity of the vacuum insulation plate is 1.2 to 1.8 mw / m·k.

[0058] The aerogel functional coating vacuum insulation panel provided in this application uses SiO2 aerogel as the main thermal insulation filler and water-based polyurethane resin as the base material. By adding various functional solvents and additives, a low thermal conductivity and high thermal insulation coating is prepared and applied to the VIP panel membrane material to produce a VIP panel with good thermal insulation performance. It is suitable for use in special environments and conditions such as cryogenic refrigerators, and can significantly improve the thermal insulation effect of VIP, greatly reducing its thermal conductivity. It also has certain anti-corrosion and anti-aging functions, extending the service life of the VIP panel. Moreover, the coating has a certain degree of adhesion, which makes the membrane material folded and bonded more firmly, avoiding the decrease in the thermal insulation capacity of the VIP panel due to folding damage. Compared with the traditional folding method, it can reduce the possibility of air leakage caused by internal wrinkles of the aluminum foil surface. That is, the sealing effect of the vacuum insulation panel is enhanced after folding, thereby reducing the failure rate of the vacuum insulation panel.

[0059] Secondly, this application provides a method for preparing a vacuum insulation panel with the above-mentioned aerogel functional coating, the method comprising:

[0060] After adding dispersant and co-solvent to deionized water and mixing them evenly, silica aerogel powder is added to obtain a mixed solution slurry.

[0061] Aqueous polyurethane resin is added to the mixed solution slurry and stirred, and defoamer and thickener are added to obtain a spraying liquid;

[0062] The coating liquid is sprayed onto the vacuum insulation panel using a spray gun, and after standing for 10 to 30 minutes, a vacuum insulation panel with an aerogel functional coating is obtained.

[0063] In some embodiments, the amount of the spraying liquid applied is 1000-5000 ml / m².

[0064] One of the main functions of aerogel functional coatings is to enhance the thermal insulation performance of vacuum insulation panels. Generally, the thicker the coating, the better the insulation effect, because a thicker coating provides more insulation material to block heat transfer. However, as the coating thickness increases to a certain extent, the improvement in thermal insulation performance gradually decreases. For example, in some cryogenic storage equipment with extremely high thermal insulation requirements, a relatively thick aerogel coating (e.g., 2-5 mm) may be needed to meet stringent insulation standards; while for vacuum insulation panels used for ordinary building exterior wall insulation, a thinner coating (e.g., 0.5-2 mm) may be sufficient. Therefore, the appropriate coating thickness must be determined based on the specific thermal insulation performance requirements.

[0065] A thicker coating may negatively impact the mechanical properties of vacuum insulation panels, such as flexibility and impact resistance. If the vacuum insulation panels need to withstand significant external forces during use (such as collisions during handling and installation), an excessively thick coating may make the panels more brittle, leading to cracking or detachment. Therefore, for applications requiring high mechanical performance, the coating thickness must be controlled within a reasonable range. For example, in building exterior wall applications, considering the potential for wind loads and impacts, the coating thickness should not be too thick, generally controlled at around 1-3 mm, to ensure good mechanical properties and durability.

[0066] Different application techniques impose certain limitations on coating thickness. For example, spraying allows for easier control of coating thickness and enables the creation of thinner coatings. Therefore, spraying typically results in a coating thickness between 0.2 and 2 millimeters. In contrast, troweling or scraping techniques may result in a coating thickness of around 0.5 to 5 millimeters, depending on the specific application conditions.

[0067] In some embodiments, the stirring speed of the mixed solution slurry is 450 r / min to 550 r / min.

[0068] In some embodiments, the stirring time is 1 to 3 hours.

[0069] The vacuum insulation panel with aerogel functional coating prepared in this application has good thermal insulation performance and is suitable for use in special environments and conditions such as cryogenic refrigerators. Compared with other methods of improving the insulation performance of VIP, this application combines traditional VIP panels with a novel aerogel functional coating. The applied aerogel functional coating can significantly improve the thermal insulation effect of VIP, greatly reducing its thermal conductivity. At the same time, it has certain anti-corrosion and anti-aging functions, extending the service life of VIP panels. It not only has excellent performance but also good environmental compatibility, which is in line with current development trends and environmental protection concepts, and effectively promotes the development of new quality productivity. Aerogel functional coating is a low thermal conductivity, high thermal insulation coating made by using SiO2 aerogel as the main thermal insulation filler and water-based polyurethane resin as the base material, and by adding a variety of functional solvents and additives. The coating has a certain degree of viscosity, which makes the membrane material folded and bonded more firmly when applied to the surface of the membrane material. This avoids the decrease in the thermal insulation capacity of the VIP panel due to folding damage. Compared with the traditional folding method, it can reduce the possibility of air leakage caused by internal wrinkles of the aluminum foil surface. In other words, the sealing effect of the vacuum insulation panel is enhanced after folding, thereby reducing the failure rate of the vacuum insulation panel and increasing the added value of the product.

[0070] Example 1

[0071] A vacuum insulation panel with an aerogel functional coating and its preparation method:

[0072] (1) Coating preparation: Dispersant and cosolvent are added to deionized water, and then the mixture is stirred and mixed thoroughly. SiO2 aerogel (commercially available) is added to make the mass fraction of SiO2 aerogel 12.0%. The mixture is stirred again to make a mixed solution slurry. The mixed solution is then added to waterborne polyurethane resin (commercially available) while stirring. The mixture is stirred at a speed not higher than 450-550 r / min for more than 1 hour to ensure uniform dispersion. Finally, appropriate amounts of defoamer and thickener are added, with a mass fraction of 0.5%. The mixture is then stirred and dispersed evenly at a low speed.

[0073] (2) VIP panel spraying: The spraying liquid is sprayed onto the VIP panel using a spray gun. After standing for 10-30 minutes, a high heat insulation coating is obtained. The spraying amount is 1000-5000 ml / m². In this embodiment, the other components are: dispersant mass fraction 1%, cosolvent mass fraction 2%, adhesive mass fraction 5%, defoamer and thickener mass fraction 0.5%, and the balance is water.

[0074] Example 2

[0075] A vacuum insulation panel with an aerogel functional coating and its preparation method:

[0076] (1) Coating preparation: Dispersant and cosolvent are added to deionized water in a ratio of 1:1. After thorough mixing, SiO2 aerogel (commercially available) is added to make the mass fraction of SiO2 aerogel 20.0%. The mixture is stirred again to make a mixed solution slurry. The mixed solution is then added to waterborne polyurethane resin (commercially available) while stirring. The mixture is stirred at a speed not exceeding 450 r / min for more than 1 hour to ensure uniform dispersion. Finally, appropriate amounts of defoamer and thickener are added, with a mass fraction of 0.5%. The mixture is then stirred at a low speed to disperse evenly.

[0077] (2) VIP panel spraying: The spraying liquid is sprayed onto the VIP panel using a spray gun. After standing for 10-30 minutes, a high heat insulation coating is obtained. The spraying amount is 1000-5000 ml / m². In this embodiment, the other components are: dispersant mass fraction 1%, cosolvent mass fraction 2%, adhesive mass fraction 5%, defoamer and thickener mass fraction 0.5%, and the balance is water.

[0078] Example 3

[0079] A vacuum insulation panel with an aerogel functional coating and its preparation method:

[0080] (1) Coating preparation: Dispersant and cosolvent are added to deionized water in a ratio of 1:1. After thorough mixing, SiO2 aerogel (commercially available) is added to make the mass fraction of SiO2 aerogel 16.0%. The mixture is stirred again to make a mixed solution slurry. The mixed solution is then added to waterborne polyurethane resin (commercially available) while stirring. The mixture is stirred at a speed not exceeding 450 r / min for more than 1 hour to ensure uniform dispersion. Finally, appropriate amounts of defoamer and thickener are added, with a mass fraction of 0.5%. The mixture is then stirred at a low speed to disperse it evenly.

[0081] (2) VIP panel spraying: The spraying liquid is sprayed onto the VIP panel using a spray gun. After standing for 10-30 minutes, a high heat insulation coating is obtained. The spraying amount is 1000-5000 ml / m². In this embodiment, the other components are: dispersant mass fraction 1.5%, cosolvent mass fraction 1.5%, adhesive mass fraction 1%, defoamer and thickener mass fraction 0.5%, and the balance is water.

[0082] Example 4

[0083] A vacuum insulation panel with an aerogel functional coating and its preparation method:

[0084] (1) Coating preparation: Dispersant and cosolvent are added to deionized water in a ratio of 1:1. After thorough mixing, SiO2 aerogel (commercially available) is added to make the mass fraction of SiO2 aerogel 16.0%. The mixture is stirred again to make a mixed solution slurry. The mixed solution is then added to waterborne polyurethane resin (commercially available) while stirring. The mixture is stirred at a speed not exceeding 450 r / min for more than 1 hour to ensure uniform dispersion. Finally, appropriate amounts of defoamer and thickener are added, with a mass fraction of 0.4%. The mixture is then stirred at a low speed to disperse evenly.

[0085] (2) VIP panel spraying: The spraying liquid is sprayed onto the VIP panel using a spray gun. After standing for 10-30 minutes, a high heat insulation coating is obtained. The spraying amount is 1000-5000 ml / m². In this embodiment, the other components are: dispersant mass fraction 2%, cosolvent mass fraction 2%, adhesive mass fraction 5%, defoamer and thickener mass fraction 0.5%, and the balance is water.

[0086] Example 5

[0087] A vacuum insulation panel with an aerogel functional coating and its preparation method:

[0088] (1) Coating preparation: Dispersant and cosolvent are added to deionized water, and then the mixture is stirred and mixed thoroughly. SiO2 aerogel (commercially available) is added to make the mass fraction of SiO2 aerogel 16.0%. The mixture is stirred again to make a mixed solution slurry. The mixed solution is then added to waterborne polyurethane resin (commercially available) while stirring. The mixture is stirred at a speed not exceeding 450 r / min for more than 1 hour to ensure uniform dispersion. Finally, appropriate amounts of defoamer and thickener are added, with a mass fraction of 0.2%. The mixture is then stirred and dispersed evenly at a low speed.

[0089] (2) VIP panel spraying: The spraying liquid is sprayed onto the VIP panel using a spray gun. After standing for 10-30 minutes, a high heat insulation coating is obtained. The spraying amount is 1000-5000 ml / m². In this embodiment, the other components are: dispersant mass fraction 1%, cosolvent mass fraction 1%, adhesive mass fraction 5%, defoamer and thickener mass fraction 0.2%, and the balance is water.

[0090] Comparative example:

[0091] To ensure the comparability of the experiments, a commercially available VIP board (Fujian Saite) without coating was used as a comparative example. The initial thermal conductivity of the VIP board was 1.5 ± 0.3 mw / mk.

[0092] Performance tests were conducted on the VIP boards corresponding to Examples 1 to 5 and the comparative examples, respectively. To ensure the validity and broad acceptance of the test results, the test method followed QB / T 2358-1998 "Test Method for Heat Seal Strength of Plastic Packaging" for heat seal strength. The thermal conductivity was measured using a JW-3 thermal conductivity meter from Beijing Jianyan Tianrun Technology Co., Ltd. The results are shown in Table 1.

[0093] Table 1

[0094]

[0095] The thermal insulation mechanism of the coating is as follows: the mesh-like porous structure of the aerogel functional coating increases the heat transfer pathway in the aerogel solid skeleton, which greatly reduces its solid phase thermal conductivity. At the same time, this structure distribution has a good effect on preventing air convection, which can reduce heat radiation and heat conduction.

[0096] As the amount of SiO2 aerogel added increases, the thermal conductivity decreases slowly. However, when the aerogel content exceeds a certain amount, it can easily lead to cracks on the coating surface. Furthermore, due to the increased aerogel content, the encapsulation of fillers by the water-based resin decreases. Increasing the amount of thickener can improve the problem of aerogel filler floating, but when the amount of thickener exceeds a certain proportion, the coating system becomes severely viscous, and sagging occurs when water is added before spraying.

[0097] This application combines traditional VIP panels with a novel aerogel functional coating, resulting in superior performance and excellent environmental compatibility. The vacuum insulation panel with this aerogel functional coating can be used not only in cryogenic refrigerators but also as a material replacement for high-performance household refrigerators and other household appliances with similar performance requirements.

[0098] As can be seen from the above embodiments, this application provides a vacuum insulation panel with an aerogel functional coating and its preparation method. The vacuum insulation panel includes the following raw materials: silica aerogel powder, dispersant, co-solvent, thickener, and adhesive; wherein the mass fraction of silica aerogel powder is 12.0% to 20.0%, the mass fraction of dispersant is 0.1% to 2%, the mass fraction of co-solvent is 1% to 5%, the amount of defoamer is 0.1% to 0.5%, the mass fraction of thickener is 0.2% to 0.5%, and the mass fraction of adhesive is 1% to 5%; the adhesive is a water-based polyurethane resin. Due to its inherent structural properties, silica aerogel coating can effectively reduce heat transfer and thus reduce energy consumption. Its internal structure, consisting of numerous uniform nanopores and multi-level fractal channel microstructures, endows silica aerogel with excellent thermal insulation properties. This structural distribution is effective in preventing air convection and can reduce heat radiation and heat conduction. Therefore, using silica aerogel with excellent thermal insulation properties in thermal insulation coatings will significantly improve the thermal insulation effect of the coating film; at the same time, adding water-based polyurethane resin can also reduce VOC emissions, enabling the vacuum insulation panel to meet market requirements.

[0099] Similar parts between the embodiments provided in this application can be referred to mutually. The specific implementation methods provided above are only a few examples under the overall concept of this application and do not constitute a limitation on the scope of protection of this application. For those skilled in the art, any other implementation methods extended from the solution of this application without creative effort shall fall within the scope of protection of this application.

Claims

1. A vacuum insulation panel with an aerogel functional coating, characterized in that, The vacuum insulation panel includes a coating and a substrate, wherein the coating comprises the following raw materials: The composition comprises silica aerogel powder, dispersant, co-solvent, thickener, and adhesive; wherein the silica aerogel powder has a mass fraction of 12.0%–20.0%, the dispersant has a mass fraction of 0.1%–2%, the co-solvent has a mass fraction of 1%–5%, the defoamer has a mass fraction of 0.1%–0.5%, the thickener has a mass fraction of 0.2%–0.5%, the adhesive has a mass fraction of 1%–5%, and the balance is water; the adhesive is an aqueous polyurethane resin. The co-solvent is any one of ethanol, isopropanol, toluene, and dichloromethane; The thermal conductivity of the vacuum insulation panel is 1.2 to 1.8 mw / m·k.

2. The vacuum insulation panel with an aerogel functional coating according to claim 1, characterized in that, The dispersant includes one of polyacrylate, polyphosphate, and organosilicon.

3. The vacuum insulation panel with an aerogel functional coating according to claim 1, characterized in that, The defoamer is one or a combination of two of organosilicon and mineral oil.

4. The vacuum insulation panel with an aerogel functional coating according to claim 1, characterized in that, The thickener is one or a combination of two of the following: associative thickener and polyurethane thickener.

5. The method for preparing the vacuum insulation panel with aerogel functional coating as described in claim 1, characterized in that, The method includes: After adding dispersant and co-solvent to deionized water and mixing them evenly, silica aerogel powder is added to obtain a mixed solution slurry. Aqueous polyurethane resin is added to the mixed solution slurry and stirred, and defoamer and thickener are added to obtain a spraying liquid; The coating liquid is sprayed onto the vacuum insulation panel using a spray gun, and after standing for 10 to 30 minutes, a vacuum insulation panel with an aerogel functional coating is obtained.

6. The method for preparing the vacuum insulation panel with aerogel functional coating according to claim 5, characterized in that, The spraying volume of the spraying liquid is 1000-5000 ml / m².

7. The method for preparing the vacuum insulation panel with aerogel functional coating according to claim 5, characterized in that, The stirring speed of the mixed solution slurry is 450 r / min to 550 r / min.

8. The method for preparing the vacuum insulation panel with aerogel functional coating according to claim 5, characterized in that, The stirring time is 1 to 3 hours.

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