Vacuum insulated panel with aerogel functional coating and preparation method of vacuum insulated panel

Abstract

The invention provides a vacuum insulation panel with an aerogel functional coating and a preparation method of the vacuum insulation panel, the vacuum insulation panel comprises the coating and a panel, and the coating comprises the following raw materials: silicon dioxide aerogel powder, a dispersing agent, a cosolvent, a thickening agent and an adhesive; and the adhesive is waterborne polyurethane resin. The silicon dioxide aerogel coating can effectively reduce heat transmission and play a role in reducing energy consumption due to the structural attribute of the silicon dioxide aerogel coating, and the internal structure of the silicon dioxide aerogel coating is a large number of nanopores and multilevel fractal pore microstructures with uniform texture, so that the silicon dioxide aerogel is endowed with excellent heat insulation performance; the structural distribution has a good effect in the aspect of preventing air convection, and heat radiation and heat conduction can be reduced. Therefore, when the silicon dioxide aerogel with excellent heat insulation performance is used in a heat insulation coating, the heat insulation effect of a coating film can be obviously improved; and meanwhile, by adding the waterborne polyurethane resin, the emission of VOC (Volatile Organic Compounds) can be reduced, so that the vacuum insulated panel meets the market requirements.

Description

Technical Field

[0001] The present application relates to the technical field of thermal insulation materials, and in particular to a vacuum insulation panel with an aerogel functional coating and a preparation method thereof. Background Art

[0002] At present, with the development of society, people's requirements and attention to environmental protection and energy conservation are increasing. Among them, thermal insulation materials headed by vacuum insulation panels (VIP panels) are increasingly widely used, especially in home appliances and construction, which leads to the continuous improvement of the performance requirements of thermal insulation materials. In addition, driven by the development of science and technology, in some special fields such as ultra-low temperature refrigerators, aerospace, etc., traditional thermal insulation materials such as foamed polyurethane, rock wool felt, polystyrene foam board, VIP board, etc., must meet certain requirements in thickness to have better thermal insulation performance, but in this case, their use scenarios and conditions will inevitably be limited. Therefore, it is urgent to seek environmentally friendly and sustainable thermal insulation materials.

[0003] As a new type of insulation material, the working principle of vacuum insulation panels is to greatly reduce the heat conduction and heat convection of air molecules in a vacuum environment, thereby achieving extremely low thermal conductivity. Usually, vacuum insulation panels are composed of core materials and barrier films. The core materials are generally porous materials such as glass fiber, polystyrene foam, etc., and the barrier films are used to seal the core materials and maintain the internal vacuum state.

[0004] Glass fiber has the advantages of light weight, good chemical stability, non-flammability, and low thermal conductivity. Its fiber structure can effectively prevent the conduction of heat and can withstand a certain amount of pressure. In addition, the cost of glass fiber is relatively low, the source is wide, and it is suitable for large-scale production. When making 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. When subjected to large external forces, the fibers may shift or be damaged, affecting the insulation performance. Polystyrene foam includes expanded polystyrene (EPS) and extruded polystyrene (XPS). EPS is a white foam material with a closed-cell structure made by heating and pre-foaming polystyrene resin particles in a mold; XPS is made by extrusion foaming process and has a tighter closed-cell structure and higher strength. They all have the advantages of light weight, low thermal conductivity, and low cost, and are widely used in the field of building insulation. However, polystyrene foam has poor heat resistance, is easily deformed in high temperature environments, and is flammable, so flame retardants need to be added to improve fire resistance.

[0005] Therefore, the core material structure of the vacuum insulation panel in the related art is not stable enough and cannot guarantee the simultaneous existence of high strength and excellent insulation performance, and does not meet the use requirements in special environments. Summary of the invention

[0006] The present application provides a vacuum insulation panel with an aerogel functional coating and a preparation method thereof, so as to solve the problem in the related art that the core material structure of the vacuum insulation panel is insufficiently stable, cannot guarantee the simultaneous existence of high strength and excellent insulation performance, and does not meet the use requirements of special environments.

[0007] In a first aspect, the present application provides a vacuum insulation panel with an aerogel functional coating, wherein the vacuum insulation panel comprises a coating and a plate, wherein the coating comprises the following raw materials:

[0008] Silica aerogel powder, dispersant, solubilizer, thickener, 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 solubilizer 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%, the mass fraction of adhesive is 1% to 5%, and the balance is water (72% to 86%); the adhesive is waterborne polyurethane resin.

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

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

[0011] In some possible implementations, the defoaming agent is one or more combinations of silicone and mineral oil.

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

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

[0014] In a second aspect, the present application provides a method for preparing the vacuum insulation panel having the above-mentioned aerogel functional coating, the method comprising:

[0015] Adding a dispersant and a co-solvent into deionized water and mixing them evenly, adding silica aerogel powder to obtain a mixed solution slurry;

[0016] Adding waterborne polyurethane resin to the mixed solution slurry and stirring the mixture, and adding a defoamer and a thickener to obtain a spraying liquid;

[0017] The spraying liquid is sprayed on the vacuum insulation panel with 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 spraying amount of the spraying liquid 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] From the above content, it can be seen that the present application provides a vacuum insulation panel with aerogel functional coating and a preparation method thereof, wherein the vacuum insulation panel includes a coating and a plate, and the coating includes the following raw materials: silica aerogel powder, dispersant, cosolvent, thickener, 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 cosolvent 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 water-based polyurethane resin. Due to its own structural properties, silica aerogel coating can effectively reduce heat transfer and play a role in reducing energy consumption. Because its internal structure is a large number of uniform nanopores and multi-level fractal channel microstructures, silica aerogel has excellent thermal insulation properties. This structural distribution has a good effect in preventing air convection, and can reduce heat radiation and heat conduction. Therefore, using silica aerogel with excellent thermal insulation performance in thermal insulation coatings will significantly improve the thermal insulation effect of the coating; at the same time, adding water-based polyurethane resin can also reduce VOC emissions, allowing the vacuum insulation panel to meet market requirements. DETAILED DESCRIPTION

[0022] At present, with the development of society, people's requirements and attention to environmental protection and energy conservation are increasing. Among them, thermal insulation materials headed by vacuum insulation panels (VIP panels) are increasingly widely used, especially in home appliances and construction, which leads to the continuous improvement of the performance requirements of thermal insulation materials. In addition, driven by the development of science and technology, in some special fields such as ultra-low temperature refrigerators, aerospace, etc., traditional thermal insulation materials such as foamed polyurethane, rock wool felt, polystyrene foam board, VIP board, etc., must meet certain requirements in thickness to have better thermal insulation performance, but in this case, their use scenarios and conditions will inevitably be limited. Therefore, it is urgent to seek environmentally friendly and sustainable thermal insulation materials.

[0023] As a new type of insulation material, the working principle of vacuum insulation panels is to greatly reduce the heat conduction and heat convection of air molecules in a vacuum environment, thereby achieving extremely low thermal conductivity. Usually, vacuum insulation panels are composed of core materials and barrier films. The core materials are generally porous materials such as glass fiber, polystyrene foam, etc., and the barrier films are used to seal the core materials and maintain the internal vacuum state.

[0024] Glass fiber has the advantages of light weight, good chemical stability, non-flammability, and low thermal conductivity. Its fiber structure can effectively prevent the conduction of heat and can withstand a certain amount of pressure. In addition, the cost of glass fiber is relatively low, the source is wide, and it is suitable for large-scale production. When making 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. When subjected to large external forces, the fibers may shift or be damaged, affecting the insulation performance. Polystyrene foam includes expanded polystyrene (EPS) and extruded polystyrene (XPS). EPS is a white foam material with a closed-cell structure made by heating and pre-foaming polystyrene resin particles in a mold; XPS is made by extrusion foaming process and has a tighter closed-cell structure and higher strength. They all have the advantages of light weight, low thermal conductivity, and low cost, and are widely used in the field of building insulation. However, polystyrene foam has poor heat resistance, is easily deformed in high temperature environments, and is flammable, so flame retardants need to be added to improve fire resistance.

[0025] Therefore, the core material structure of the vacuum insulation panel in the related art is not stable enough and cannot guarantee the simultaneous existence of high strength and excellent insulation performance, and does not meet the use requirements in special environments.

[0026] Based on this, the present application provides a vacuum insulation panel with aerogel functional coating and a preparation method thereof, wherein silica aerogel is used as the main insulation filler, and waterborne polyurethane resin is used as the base material, and a low thermal conductivity high insulation coating is prepared by adding a variety of functional solvents and additives, and applied on the VIP board film material to prepare a VIP board with good thermal insulation performance, which is suitable for use in special environments and conditions such as deep-freeze refrigerators, and can significantly improve the thermal insulation effect of VIP, greatly reducing its thermal conductivity, and also has certain anti-corrosion, anti-aging and attenuation functions, extending the service life of the VIP board. In addition, the coating has a certain viscosity, and when applied on the surface of the film material, the film material folding is more firmly bonded, avoiding the decrease in the insulation capacity of the VIP board due to the damage of the folding. Compared with the traditional folding method, it can reduce the possibility of air leakage caused by the internal wrinkles of the aluminum foil surface, that is, the sealing effect of the vacuum insulation panel is enhanced after the folding, thereby reducing the failure rate of the vacuum insulation panel.

[0027] In some embodiments, the vacuum insulation panel with aerogel functional coating provided by the present application includes a coating and a plate, wherein the coating includes the following raw materials:

[0028] Silica (SiO2) aerogel powder, dispersant, solubilizer, thickener, 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 solubilizer 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 water-based polyurethane resin.

[0029] SiO2 aerogel is a new type of solid material with a three-dimensional skeleton network structure formed by Si-O-Si bond polycondensation. It has the characteristics of low density, low thermal conductivity, high porosity, and high specific surface area, so it is popular as a functional filler for coating products. However, due to the insufficient mechanical properties, poor toughness, and easy breakage of the block aerogel, which increases the difficulty and cost of use, it is usually doped into a film-forming resin. Therefore, the preparation of SiO2 aerogel coating is through a designed formula, adding dispersants and other additives, and first preparing these ingredients into slurry through a dispersion process; then mixing the slurry with silicone resin, additives, defoaming agents and other fillers; finally, after dispersion treatment, the coating is prepared.

[0030] SiO2 aerogel thermal insulation coating can effectively reduce heat transmission and reduce energy consumption due to its own structural properties (the three-dimensional mesh porous structure increases the heat transfer path in the aerogel solid skeleton, which greatly reduces its solid phase thermal conductivity. Because the internal structure is a large number of uniform nanopores and multi-level fractal channel microstructures, SiO2 aerogel has excellent thermal insulation properties. This structural distribution has a good effect in preventing air convection and can reduce thermal radiation and heat conduction). Therefore, using SiO2 aerogel with excellent thermal insulation properties in thermal insulation coatings will significantly improve the thermal insulation effect of the coating. When SiO2 aerogel is wrapped in a resin with excellent mechanical properties (the role of water-based resin), it can avoid the disadvantage of brittle fracture when deformed.

[0031] SiO2 aerogel itself has an extremely low thermal conductivity and is one of the best known solid materials for thermal insulation. When it is made into a functional coating and applied to a traditional VIP panel, the nanoporous structure of the aerogel can greatly hinder the conduction of heat. Its pore size is extremely small, smaller than the mean free path of air molecules. The heat conduction of air molecules in the pores is greatly restricted, making it difficult for heat to be transferred through the coating, thereby reducing the overall thermal conductivity. Even when the vacuum degree decreases, the aerogel coating can continue to play a role with its excellent thermal insulation performance, making up for the problem of reduced thermal insulation performance caused by the decrease in vacuum degree, and further improving the thermal insulation performance of the vacuum insulation panel. Traditional VIP panels mainly rely on the internal vacuum environment to reduce the thermal conduction of gas molecules to achieve thermal insulation. The addition of aerogel functional coating introduces a new thermal insulation mechanism. In addition to the low thermal conductivity of aerogel itself, the coating can also prevent thermal radiation and thermal convection to a certain extent. The porous structure of aerogel can scatter and absorb thermal radiation and reduce radiation heat transfer; at the same time, the presence of the coating can also inhibit the convective heat exchange between the external air and the surface of the VIP panel to a certain extent. In this way, the vacuum insulation mechanism of the traditional VIP panel and the multiple insulation mechanisms of the aerogel functional coating work synergistically 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] As the carrier of aerogel, waterborne polyurethane resin can not only evenly coat aerogel on the surface of VIP panel, but also has good adhesion and sealing properties. It can effectively seal the tiny gaps or defects that may exist in the VIP panel, prevent air from entering the vacuum layer, thereby maintaining the vacuum degree inside the VIP panel and further improving the thermal insulation performance. At the same time, the coating formed by waterborne polyurethane resin can also protect the VIP panel, prevent damage to the VIP panel by the external environment, extend its service life, and ensure the long-term stability of its thermal insulation performance.

[0033] Waterborne polyurethane resin uses water as solvent, and the emission of volatile organic compounds (VOC) is extremely low during production, construction and use. In contrast, solvent-based resins usually contain a large amount of organic solvents, which pollute the atmospheric environment during volatilization and may endanger human health, causing respiratory diseases, nervous system damage and other problems. Some waterborne polyurethane resins have a certain degree of biodegradability and can be gradually decomposed by microorganisms in the natural environment, reducing long-term pollution to the environment. However, some traditional resins, such as phenolic resins and epoxy resins, are difficult to biodegrade and will remain in the environment for a long time after being discarded, causing environmental pollution.

[0034] Waterborne polyurethane resin has good sealing properties, which can prevent outside air and moisture from entering the vacuum insulation panel and maintain its internal vacuum degree. The stability of the vacuum degree is crucial to reducing thermal conductivity, because the vacuum environment can effectively reduce gas heat conduction. At the same time, the resin coating can also protect the aerogel from erosion and damage by external factors, ensuring the long-term effectiveness of the thermal insulation performance.

[0035] Waterborne polyurethane resin has good flexibility and elasticity, and can form a continuous and elastic film structure in the coating. This property enables the coating to effectively disperse stress when it is impacted or deformed by external forces, avoiding cracks or shedding of the coating, thereby improving the durability and service life of the coating.

[0036] Waterborne polyurethane resin can firmly combine the coating with the vacuum insulation panel substrate, ensuring that the coating is not easy to fall off during use, and improving the overall stability and durability of the vacuum insulation panel. Using water as a solvent instead of traditional organic solvents, almost no organic solvents are volatilized during use, reducing pollution to the environment, meeting environmental protection requirements, and can be widely used in buildings, home appliances and other fields with high environmental protection requirements. Waterborne polyurethane resin can give the vacuum insulation panel coating good flexibility, wear resistance and impact resistance. During the transportation, installation and use of the vacuum insulation panel, it can resist a certain degree of external forces such as friction and collision, and is not prone to damage, cracking and other problems.

[0037] Waterborne polyurethane resin can be constructed at room temperature, is simple and convenient to operate, and is easy to coat on the surface of vacuum insulation panels. It can adapt to different construction environments and process requirements. It also dries relatively quickly, which can improve production efficiency. Waterborne polyurethane resin is well compatible with a variety of other materials and additives, and can be easily used with silica aerogel and other functional additives to meet different performance requirements. It can also cooperate with other components of vacuum insulation panels without affecting the overall insulation performance.

[0038] As a carrier of aerogel, waterborne polyurethane resin can firmly fix aerogel on the surface of vacuum insulation panel to form a stable coating structure. This stable structure helps to keep the nanoporous structure of aerogel intact and ensure the stability of its thermal insulation performance. The resin can fill the tiny gaps and defects that may exist on the surface and inside of the vacuum insulation panel, reducing the channels for heat transfer. It can also cooperate with aerogel to form a denser insulation layer, further reducing thermal conductivity.

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

[0040] When selecting a dispersant, the chemical structure and polarity of the dispersant should be compatible with the system components such as waterborne polyurethane resin and silica aerogel. For example, in a water-based system, hydrophilic dispersants should be preferred. Anionic dispersants, such as polyacrylates, can be well mixed with waterborne polyurethane resins and have good affinity for the surface of silica aerogels, which can effectively reduce the surface energy of particles and achieve uniform dispersion. Dispersants cannot chemically react with other additives in the coating to avoid affecting the performance of the coating. For example, some amine-containing dispersants may react with acidic additives, resulting in system instability, so the chemical properties of each component must be fully understood when selecting.

[0041] Dispersants should be able to significantly reduce the surface tension of aerogel particles, making them easier to disperse in the system. Non-ionic dispersants, such as polyether dispersants, can form an adsorption layer on the surface of aerogel particles through their molecular chains, reduce surface tension, and prevent particle agglomeration. Dispersants with good steric hindrance effects can prevent dispersed aerogel particles from agglomerating again. For example, polymer dispersants, with their longer molecular chains, can form a thick adsorption layer on the surface of particles, generating steric hindrance and keeping the particles dispersed.

[0042] The surface of silica aerogel usually contains a large number of hydroxyl groups and has a certain degree of hydrophilicity. The selected dispersant should be able to interact with these hydroxyl groups to achieve good dispersion. Silane coupling agent dispersants, one end of which can react with the hydroxyl groups on the surface of the aerogel, and the other end can be compatible with the coating system, thereby improving the dispersibility of the aerogel. If the aerogel particle size is small or the shape is irregular, a stronger dispersant may be required. Superdispersants have a better dispersing effect on aerogel particles with small particle size and irregular shape. It can make the particles evenly dispersed through various mechanisms of action, such as electrostatic repulsion and steric hindrance.

[0043] The addition of dispersants cannot reduce the thermal insulation performance of aerogel functional coatings. Some dispersants may fill the pores of aerogels and affect their thermal insulation effect. Therefore, thermal insulation performance tests should be carried out when selecting to ensure that the use of dispersants will not have a negative impact on thermal insulation performance. The effects of dispersants on the mechanical properties and fire resistance of the coating should also be considered. For example, some dispersants may affect the hardness and flexibility of the coating, or reduce its fire resistance level. It is necessary to select the appropriate dispersant after comprehensive evaluation.

[0044] Therefore, the present application selects one of polyacrylate, polyphosphate and silicone as the dispersant in combination with the above factors.

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

[0046] When selecting a co-solvent, the chemical structure and polarity of the co-solvent should be compatible with the waterborne polyurethane resin, silica aerogel and other formulation ingredients. For example, for a water-based system, a co-solvent with a certain hydrophilicity should be selected, such as alcohols (ethanol, propylene glycol, etc.) or ethers (ethylene glycol butyl ether). These co-solvents are well miscible with water and waterborne polyurethane resins, and can also help the aerogel to be better dispersed in the system. The co-solvent cannot react chemically with other components in the coating to avoid affecting the stability and performance of the coating. For example, some strongly acidic or alkaline co-solvents may react with functional groups in the waterborne polyurethane resin, resulting in coagulation or hydrolysis of the resin, so such co-solvents should be avoided.

[0047] One of the main functions of the cosolvent is to reduce the viscosity of the coating system and improve its fluidity and construction performance. It is very important to select a cosolvent that can effectively reduce the viscosity of the system. Some low-boiling alcohol cosolvents, such as methanol and ethanol, have good dilution ability and can quickly reduce the viscosity of the coating, but they are highly volatile and may have a certain impact on the environment and construction safety. Therefore, it is necessary to select a suitable cosolvent and its dosage according to the specific situation. The cosolvent should be able to improve the solubility of components such as waterborne polyurethane resin and aerogel in the system to ensure the uniformity and stability of the coating. For example, some ketone cosolvents (such as acetone and butanone) have strong solubility and can promote the dissolution and dispersion of resins and aerogels, but their volatility and safety also need to be noted. The surface of silica aerogel usually has a certain hydrophilicity or hydrophobicity, and the selection of cosolvents should consider the matching with the surface properties of the aerogel. For hydrophilic aerogels, a co-solvent with strong hydrophilicity can be selected to enhance its dispersion and dissolution in the system; for hydrophobic aerogels, a co-solvent with a certain hydrophobicity can be selected, such as certain ester co-solvents (ethyl acetate, butyl acetate).

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

[0049] Therefore, in the present application, the co-solvent is any one of ethanol, isopropanol, toluene and dichloromethane in combination with the above factors.

[0050] In some embodiments, the defoaming agent is a combination of one or more of silicone and mineral oil.

[0051] When selecting a defoamer, the defoamer must have good compatibility with the waterborne polyurethane resin, silica aerogel and other additives in the aerogel functional coating. If the defoamer is incompatible with the system, it may cause surface defects such as shrinkage holes and fish eyes in the coating, affecting the appearance and performance of the coating. For example, for waterborne polyurethane resin systems, waterborne defoamers such as polyether or silicone waterborne defoamers should be preferred. The polyether chain segments in the molecular structure of polyether defoamers can interact with the polar groups in the waterborne polyurethane resin and have good compatibility; and silicone waterborne defoamers, through special modification treatments, can also be stably dispersed in the waterborne system and are compatible with components such as waterborne polyurethane resins and aerogels.

[0052] The main function of the defoamer is to eliminate bubbles generated during the preparation and construction of the coating, and to inhibit the re-generation of bubbles within a certain period of time. Defoamers with high-efficiency defoaming and long-lasting anti-foaming properties should be selected. Silicone defoamers usually have strong defoaming ability and can quickly destroy the surface tension of bubbles and burst them. Polyether defoamers are more prominent in anti-foaming, and their molecular chains can form a dynamic protective film in the system to prevent the generation of bubbles. In actual selection, a single defoamer or a combination of different types of defoamers can be selected according to the specific bubble generation situation and the requirements for defoaming and anti-foaming properties to achieve the best effect. The addition of defoamers cannot have a negative impact on other properties of aerogel functional coatings. For example, the thermal insulation, mechanical properties, and fire resistance of the coating cannot be reduced. Some defoamers may migrate in the coating, affect the adhesion between the coating and the substrate, or change the surface gloss of the coating. Therefore, when selecting a defoamer, performance testing is required to evaluate its impact on various properties of the coating. By preparing coating samples with different defoamers added, thermal insulation performance tests, tensile strength tests, fire resistance tests, etc. can be carried out to ensure that the selected defoamer will not have an adverse effect on the key properties of the coating.

[0053] Considering that aerogel functional coatings may be used in different temperature environments, the defoamer should have a certain temperature resistance. In high temperature environments, the defoamer cannot decompose or lose its defoaming effect; in low temperature environments, it cannot solidify or thicken, which will affect 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; for coatings used in normal or low temperature environments, polyether defoamers may be more suitable.

[0054] Different construction processes have different requirements for defoamers. For example, when using the spraying process, the defoamer needs to have good dispersibility and low surface tension to ensure that bubbles can be quickly eliminated during the spraying process and will not affect the atomization effect and uniformity of the coating; while when using the scraping or smearing process, the defoaming speed and anti-foaming time of the defoamer need to match the construction speed to avoid the generation of new bubbles during the construction process. When choosing a defoamer, you should choose a defoamer product that can meet the requirements of the specific construction process.

[0055] Therefore, the defoaming agent in the present application is a combination of one or more of silicone and mineral oil in combination with the above factors.

[0056] In some embodiments, the thickener is a combination of an associative thickener and a polyurethane thickener.

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

[0058] The vacuum insulation board with aerogel functional coating provided by the present application uses SiO2 aerogel as the main insulation filler and water-based polyurethane resin as the base material. By adding a variety of functional solvents and additives, a low thermal conductivity high insulation coating is prepared, which is applied on the VIP board film material to prepare a VIP board with good insulation and heat preservation performance. It is suitable for use in special environments and conditions such as deep-freeze refrigerators, and can significantly improve the insulation effect of VIP, greatly reducing its thermal conductivity. It also has certain anti-corrosion and anti-aging decay functions, extending the service life of the VIP board. In addition, the coating has a certain viscosity. When applied to the surface of the film material, the folding edge of the film material is more firmly bonded, avoiding the reduction of the insulation capacity of the VIP board due to the damage of the folding edge. Compared with the traditional folding edge method, it can reduce the possibility of air leakage caused by the internal wrinkles of the aluminum foil surface, that is, the sealing effect of the vacuum insulation board is enhanced after the folding edge, thereby reducing the failure rate of the vacuum insulation board.

[0059] In a second aspect, the present application provides a method for preparing the vacuum insulation panel having the above-mentioned aerogel functional coating, the method comprising:

[0060] Adding a dispersant and a co-solvent into deionized water and mixing them evenly, adding silica aerogel powder to obtain a mixed solution slurry;

[0061] Adding waterborne polyurethane resin to the mixed solution slurry and stirring the mixture, and adding a defoamer and a thickener to obtain a spraying liquid;

[0062] The spraying liquid is sprayed on the vacuum insulation panel with 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 spraying amount of the spraying liquid is 1000-5000 ml / m2.

[0064] One of the main functions of aerogel functional coatings is to improve the thermal insulation performance of vacuum insulation panels. Generally speaking, the thicker the coating, the better the thermal insulation effect may be, because thicker coatings can provide more insulation materials to block heat transfer. However, when the coating thickness increases to a certain extent, the improvement in thermal insulation performance will gradually decrease. For example, in some low-temperature storage equipment with extremely high thermal insulation requirements, a relatively thick aerogel coating (such as 2-5 mm) may be required to meet strict thermal insulation standards; while for vacuum insulation panels used for insulation of ordinary building exterior walls, a thinner coating (such as 0.5-2 mm) may be sufficient to meet the needs. Therefore, the appropriate coating thickness needs to be determined based on the specific thermal insulation performance index requirements.

[0065] Thicker coatings may have a certain impact on the mechanical properties of vacuum insulation panels, such as flexibility and impact resistance. If the vacuum insulation panels need to withstand large external forces during use (such as collisions during transportation and installation), too thick a coating may make the panels more brittle and prone to cracking or falling off. Therefore, for application scenarios with higher mechanical performance requirements, the coating thickness needs to be controlled within a reasonable range. For example, in building exterior wall applications, considering that the panels may be subjected to external forces such as wind loads and impacts, the coating thickness should not be too thick and is generally controlled at around 1-3 mm to ensure that the panels have good mechanical properties and durability.

[0066] Different construction processes have certain restrictions on coating thickness. For example, when using the spraying process, the coating thickness is easier to control and a thinner coating can be achieved. Therefore, if the spraying process is used, the coating thickness can generally be controlled between 0.2-2 mm; while the coating thickness of the scraping or smearing process may be around 0.5-5 mm, and the specific adjustment needs to be made according to the actual situation.

[0067] In some embodiments, the mixed solution slurry is stirred at a speed of 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 the present application has good thermal insulation performance and is suitable for use in special environments and conditions such as deep-freeze refrigerators. Compared with other improvement methods for increasing the thermal insulation performance of VIP, the present application combines traditional VIP panels with novel aerogel functional coatings. 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 and attenuation functions, extending the service life of the VIP panel. It not only has excellent performance, but also has good environmental compatibility, conforms to the current development trend and environmental protection concept, and effectively promotes the development of new quality productivity. Aerogel functional coating is made of SiO2 aerogel as the main thermal insulation filler and water-based polyurethane resin as the base material. It is prepared into a low thermal conductivity and high thermal insulation coating by adding a variety of functional solvents and additives. The coating has a certain viscosity. When applied to the surface of the membrane material, the membrane edge bonding is more firmly achieved, thus avoiding the decrease in the thermal insulation capacity of the VIP board due to edge damage. Compared with the traditional folding method, it can reduce the possibility of air leakage caused by the 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, and the product has greater room for added value.

[0070] Example 1

[0071] A vacuum insulation panel with aerogel functional coating and a preparation method thereof:

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

[0073] (2) VIP board spraying: spray the spraying liquid on the VIP board with a spray gun, and after standing for 10-30 minutes, a high thermal insulation coating is obtained, and the spraying amount is 1000-5000 ml / m2. Among them, the other components of this embodiment are 1% by mass of the dispersant, 2% by mass of the co-solvent, 5% by mass of the adhesive, 0.5% by mass of the defoamer and the thickener, and the balance is water.

[0074] Example 2

[0075] A vacuum insulation panel with aerogel functional coating and a preparation method thereof:

[0076] (1) Preparation of coating: Dispersant and co-solvent were added to deionized water in a ratio of 1:1, and then the mixture was stirred thoroughly. SiO2 aerogel (commercially available) was added to make the mass fraction of SiO2 aerogel 20.0%, and the mixture was stirred again to make a mixed solution slurry. The mixed solution was then added to a waterborne polyurethane resin (commercially available) while stirring, and stirred for more than 1 h at a speed not higher than 450 r / min to ensure uniform dispersion. Finally, appropriate amounts of defoamer and thickener were added, with a mass fraction of 0.5%, and the mixture was stirred at a low speed to disperse uniformly.

[0077] (2) VIP board spraying: spray the spraying liquid on the VIP board with a spray gun, and after standing for 10-30 minutes, a high thermal insulation coating is obtained, and the spraying amount is 1000-5000 ml / m2. Among them, the other components of this embodiment are 1% by mass of the dispersant, 2% by mass of the co-solvent, 5% by mass of the adhesive, 0.5% by mass of the defoamer and the thickener, and the balance is water.

[0078] Example 3

[0079] A vacuum insulation panel with aerogel functional coating and a preparation method thereof:

[0080] (1) Preparation of coating: Dispersant and co-solvent were added to deionized water in a ratio of 1:1, and then the mixture was stirred thoroughly. SiO2 aerogel (commercially available) was added to make the mass fraction of SiO2 aerogel 16.0%. The mixture was stirred again to make a mixed solution slurry. The mixed solution was then added to a waterborne polyurethane resin (commercially available) while stirring. The mixture was stirred for more than 1 h at a speed of not more than 450 r / min to ensure uniform dispersion. Finally, appropriate amounts of defoamer and thickener were added, with a mass fraction of 0.5%, and the mixture was stirred at a low speed to disperse the mixture evenly.

[0081] (2) VIP board spraying: spray the spraying liquid on the VIP board with a spray gun, and after standing for 10-30 minutes, a high thermal insulation coating is obtained, and the spraying amount is 1000-5000 ml / m2. Among them, the other components of this embodiment are 1.5% by mass of the dispersant, 1.5% by mass of the co-solvent, 1% by mass of the adhesive, 0.5% by mass of the defoamer and the thickener, and the balance is water.

[0082] Example 4

[0083] A vacuum insulation panel with aerogel functional coating and a preparation method thereof:

[0084] (1) Preparation of coating: Dispersant and co-solvent were added to deionized water in a ratio of 1:1, and then the mixture was stirred thoroughly. SiO2 aerogel (commercially available) was added to make the mass fraction of SiO2 aerogel 16.0%, and the mixture was stirred again to make a mixed solution slurry. The mixed solution was then added to a waterborne polyurethane resin (commercially available) while stirring, and stirred for more than 1 h at a speed not higher than 450 r / min to ensure uniform dispersion. Finally, appropriate amounts of defoamer and thickener were added, with a mass fraction of 0.4%, and the mixture was stirred at a low speed to disperse uniformly.

[0085] (2) VIP board spraying: spray the spraying liquid on the VIP board with a spray gun, and after standing for 10-30 minutes, obtain a high thermal insulation coating, and the spraying amount is 1000-5000 ml / m2. Among them, the other components of this embodiment are 2% by mass of the dispersant, 2% by mass of the co-solvent, 5% by mass of the adhesive, 0.5% by mass of the defoamer and the thickener, and the balance is water.

[0086] Example 5

[0087] A vacuum insulation panel with aerogel functional coating and a preparation method thereof:

[0088] (1) Preparation of coating: Dispersant and cosolvent were added to deionized water respectively, and then stirred thoroughly to mix, and then SiO2 aerogel (commercially available) was added to make the mass fraction of SiO2 aerogel 16.0%, and stirred again to make a mixed solution slurry, and then the mixed solution was added to waterborne polyurethane resin (commercially available) while stirring, and stirred at a speed of not more than 450 r / min for more than 1 h to ensure uniform dispersion, and finally, appropriate amounts of defoamer and thickener were added respectively, with a mass fraction of 0.2%, and then stirred at a low speed to disperse evenly.

[0089] (2) VIP board spraying: spray the spraying liquid on the VIP board with a spray gun, and after standing for 10-30 minutes, obtain a high thermal insulation coating, and the spraying amount is 1000-5000 ml / m2. Among them, the other components of this embodiment are 1% by mass of the dispersant, 1% by mass of the co-solvent, 5% by mass of the adhesive, 0.2% by mass of the defoamer and the thickener, and the balance is water.

[0090] Comparative Example:

[0091] In order to ensure the comparability of the experiments, the common commercially available VIP board (Fujian Saite) not coated with paint in the embodiment was used as a comparative example for comparison, and the initial thermal conductivity of the VIP board was 1.5±0.3 mw / mk.

[0092] The VIP boards corresponding to Examples 1 to 5 and the comparative examples were tested for performance. To ensure the validity and wide recognition of the test results, the test method was based on the heat seal strength using QB / T 2358-1998 "Test Method for Heat Seal Strength of Plastic Packaging"; the thermal conductivity was measured using the JW-3 thermal conductivity tester of 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 layer is: the reticular porous structure of the aerogel functional coating increases the heat transfer path in the aerogel solid skeleton, which greatly reduces its solid phase thermal conductivity. At the same time, this structural distribution has a good effect in preventing air convection, which can reduce thermal radiation and heat conduction.

[0096] As the amount of SiO2 aerogel added increases, the thermal conductivity slowly decreases, but when the aerogel content exceeds a certain amount, it is easy to cause cracks on the coating surface, and due to the increase in aerogel content, the degree of water-based resin wrapping the filler will decrease. Increasing the amount of thickener added 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 spraying after adding water.

[0097] This application combines the traditional VIP board with the new aerogel functional coating, which not only has excellent performance but also good environmental compatibility. In addition to being used in deep-freezers, the vacuum insulation board with the aerogel functional coating can also be used as a replacement for materials in household refrigerators with high performance requirements and other household appliances with related performance requirements.

[0098] It can be seen from the above embodiments that the present application provides a vacuum insulation panel with aerogel functional coating and a preparation method thereof, wherein the vacuum insulation panel comprises the following raw materials: silica aerogel powder, dispersant, cosolvent, 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 cosolvent 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 own structural properties, silica aerogel coating can effectively reduce heat transfer and play a role in reducing energy consumption. Because its internal structure is a large number of uniform nanopores and multi-level fractal channel microstructures, silica aerogel has excellent thermal insulation properties. This structural distribution has a good effect in preventing air convection, and can reduce heat radiation and heat conduction. Therefore, using silica aerogel with excellent thermal insulation performance in thermal insulation coatings will significantly improve the thermal insulation effect of the coating; at the same time, adding water-based polyurethane resin can also reduce VOC emissions, allowing the vacuum insulation panel to meet market requirements.

[0099] Similar parts between the embodiments provided in this application can be referenced to each other. The specific implementation methods provided above are only a few examples under the general concept of this application and do not constitute a limitation on the protection scope of this application. For those skilled in the art, any other implementation methods expanded based on the scheme of this application without creative work belong to the protection scope of this application.

Claims

1. A vacuum insulation panel with an aerogel functional coating, characterized in that: The vacuum insulation panel comprises a coating and a plate, wherein the coating comprises the following raw materials: Silica aerogel powder, dispersant, solubilizer, thickener, 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 solubilizer 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%, the mass fraction of adhesive is 1% to 5%, and the balance is water; the adhesive is waterborne polyurethane resin.

2. The vacuum insulation panel with 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 aerogel functional coating according to claim 1, characterized in that: The co-solvent is any one of ethanol, isopropanol, toluene and dichloromethane.

4. The vacuum insulation panel with aerogel functional coating according to claim 1, characterized in that: The defoaming agent is one or more combinations of silicone and mineral oil.

5. The vacuum insulation panel with aerogel functional coating according to claim 1, characterized in that: The thickener is an associative thickener and a polyurethane thickener or a combination thereof.

6. The vacuum insulation panel with aerogel functional coating according to claim 1, characterized in that: The thermal conductivity of the vacuum insulation panel is 1.2 to 1.8 mw / m·k.

7. The method for preparing a vacuum insulation panel with aerogel functional coating according to claim 1, characterized in that: The method comprises: Adding a dispersant and a co-solvent into deionized water and mixing them evenly, adding silica aerogel powder to obtain a mixed solution slurry; Adding waterborne polyurethane resin to the mixed solution slurry and stirring the mixture, and adding a defoamer and a thickener to obtain a spraying liquid; The spraying liquid is sprayed on the vacuum insulation panel with a spray gun, and after standing for 10 to 30 minutes, a vacuum insulation panel with an aerogel functional coating is obtained.

8. The method for preparing a vacuum insulation panel with aerogel functional coating according to claim 7, characterized in that: The spraying amount of the spraying liquid is 1000 to 5000 ml / m2.

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

10. The method for preparing a vacuum insulation panel with aerogel functional coating according to claim 7, characterized in that: The stirring time is 1 to 3 hours.

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