Low-absorption high-emission thermal insulation coating as well as preparation method and application thereof

Abstract

The invention relates to the technical field of surface engineering, and particularly discloses a low-absorption high-emission thermal insulation coating as well as a preparation method and application thereof. The coating comprises a high-temperature-resistant polymer binder, an inorganic functional filler, hollow microspheres, reinforcing fibers, an organic solvent and a curing agent, the hollow microspheres comprise first hollow microspheres with the diameter of 100-120 [mu] m and second hollow microspheres with the diameter of 10-20 [mu] m; the inorganic functional filler comprises a first inorganic functional filler with a particle size of 4-6 [mu] m and a second inorganic functional filler with a particle size of 0.3-0.7 [mu] m. According to the coating, multiple functional components are added for combined design, the solar absorptivity, the hemispherical emissivity and the heat conductivity are cooperatively regulated and controlled, the compression resistance, the pneumatic scouring resistance, the vibration resistance and the high temperature resistance of the coating are improved, a high polymer resistant to ablation and high temperature is used as a binder, and the coating with low absorption, high emissivity and heat insulation performance is prepared.

Description

Technical Field

[0001] The present application relates to the field of surface engineering technology, and in particular to a low-absorption, high-emission thermal insulation coating, a preparation method thereof, and an application thereof. Background Art

[0002] Near-space new concept aircraft are new aircraft capable of long-term, sustained, high-speed flight and high maneuverability in near-space, 20-100 kilometers above the Earth. Due to the high flight speeds, large temperature swings, and harsh environments, near-space aircraft require a long-life, lightweight, high-heat-dissipation, and high-insulation protective coating to protect the integrity of their internal structure and functions.

[0003] Currently, spacecraft in high orbits primarily utilize thermal control coatings for thermal protection. However, due to the high temperatures generated by friction with the air during high-speed flight, spacecraft in the atmosphere require thermal insulation coatings to protect the interior of the spacecraft from high-temperature damage. To meet the cross-space, high-Mach, and long-endurance flight requirements of new-concept near-space spacecraft and to more effectively protect the structure and function of the spacecraft, thermal insulation coatings with low absorption and high emission have become an important new protective coating for these new-concept near-space spacecraft. Summary of the Invention

[0004] In view of this, the purpose of the present application is to provide a low-absorption, high-emission thermal insulation coating and a preparation method thereof, so that the coating formed by the low-absorption, high-emission thermal insulation coating not only has excellent heat resistance, but also has better space thermal control performance, and is mainly suitable for protective coatings of new concept aircraft in near-space and cross-space;

[0005] Another object of the present application is to provide the application of the above-mentioned low-absorption, high-emission thermal insulation coating in the preparation of coatings and substrates with low absorption, high emission and thermal insulation properties.

[0006] In order to solve the above-mentioned technical problems / achieve the above-mentioned purposes or at least partially solve the above-mentioned technical problems / achieve the above-mentioned purposes, as the first aspect of the present application, a low-absorption and high-emission thermal insulation coating is provided, comprising a high-temperature resistant polymer binder, an inorganic functional filler, hollow microspheres, reinforcing fibers, an organic solvent and a curing agent; the hollow microspheres comprise first hollow microspheres with a diameter of 100-120 μm and second hollow microspheres with a diameter of 10-20 μm; the inorganic functional filler comprises a first inorganic functional filler with a particle size of 4-6 μm and a second inorganic functional filler with a particle size of 0.3-0.7 μm.

[0007] Optionally, the low-absorption and high-emission thermal insulation coating comprises, by weight, 10-100 parts of a high-temperature resistant polymer binder, 20-150 parts of an inorganic functional filler, 8-90 parts of hollow microspheres, 10-50 parts of reinforcing fibers, 10-150 parts of an organic solvent, and a curing agent accounting for 1-10% of the mass of the high-temperature resistant polymer binder.

[0008] Further optionally, the high temperature resistant polymer binder includes one or more of methyl diphenyl silicone rubber, methyl phenyl vinyl silicone rubber, epoxy modified silicone resin, pure silicone resin, and phenolic resin; the inorganic functional filler includes one or more of ZnO, TiO2, ZrO2, and Zn2TiO4; the hollow microspheres are hollow microspheres made of oxygen-containing materials; the reinforcing fibers include one or more of glass fibers, phenolic fibers, and aluminum silicate fibers; the organic solvent includes one or more of xylene, butyl acetate, and n-heptane; and the curing agent is selected from tetraethyl orthosilicate, dibutyltin dilaurate, hydroxy silicone oil, dipentadienyl vulcanizer, hexamethylenetetramine, and silane coupling agent according to the type of polymer.

[0009] As a second aspect of the present application, a method for preparing the low-absorption, high-emission thermal insulation coating is provided, comprising:

[0010] S1. The high temperature resistant polymer binder is poured into an organic solvent and dissolved and dispersed to prepare a solution A;

[0011] S2. An inorganic functional filler was added to the solution A and stirred to mix to prepare a solution B;

[0012] S3. The hollow microspheres and reinforcing fibers were added to the solution B, and then stirred to prepare a solution C;

[0013] S4. Add a curing agent to the solution C, stir and mix evenly to prepare a low-absorption and high-emission thermal insulation coating.

[0014] As a third aspect of the present application, there is provided the use of the low-absorption, high-emission thermal insulation coating in the preparation of coatings and substrates with low-absorption, high-emission and thermal insulation properties.

[0015] As a fourth aspect of the present application, a coating with low absorption, high emission and heat insulation performance is provided, which is formed by drying the low absorption and high emission heat insulation coating described in the present application.

[0016] As a fifth aspect of the present application, a substrate with low absorption, high emission and heat insulation performance is provided, comprising a substrate and the coating described in the present application coated on the surface of the substrate.

[0017] Optionally, the substrate is metal.

[0018] The low-absorption and high-emission thermal insulation coating provided in this application is designed by adding a variety of functional components to coordinately regulate the solar absorptivity, hemispherical emissivity, and thermal conductivity, thereby improving the coating's resistance to pressure, aerodynamic erosion, vibration, and high-temperature resistance. By using ablation-resistant and high-temperature resistant polymers as binders, a coating with low absorption, high emissivity, and thermal insulation properties is prepared, which is particularly suitable for protective coatings for new concept aircraft in near-space and cross-space. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The exemplary embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application.

[0020] Figure 1 Shown is a microscopic image of the coating surface formed using the coating described in this application;

[0021] Figure 2 Shown are intuitive images of the coating formed in Example 1 before and after being heated by 600°C quartz lamp radiation. DETAILED DESCRIPTION

[0022] The present application discloses a low-absorption, high-emission thermal insulation coating, and a preparation method and application thereof. Those skilled in the art can refer to the content of this article and appropriately improve the process parameters to achieve it. It is particularly important to point out that all similar replacements and modifications are obvious to those skilled in the art, and they are all deemed to be included in this application. The products, processes and applications described in this application have been described through preferred embodiments. Relevant personnel can obviously modify or appropriately change and combine the methods described herein without departing from the content, spirit and scope of this application to implement and apply the technology of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0023] It should be noted that, in this document, if relational terms such as "first" and "second", "step 1" and "step 2", and "(1)" and "(2)" appear, they are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "including a..." do not exclude the presence of other identical elements in the process, method, article or device comprising the elements. At the same time, the embodiments in this application and the features in the embodiments can be combined with each other in the absence of conflict.

[0024] The microspheres / microbeads used in existing thermal insulation coatings are usually only available in a single size and have high fluidity. After the coating is formed, if it is placed in an extreme environment in near-space or across space, the friction and impact between the aircraft and the air during high-speed flight will cause the coating to decompose and fall off, resulting in a short service life, making it difficult to effectively protect the structure and normal function of the aircraft. In addition, existing thermal insulation coatings usually only focus on the thermal insulation effect (thermal conductivity) and ignore the space thermal control performance, such as solar absorption ratio and hemispherical emissivity. Aircraft operating in near-space and across space need to face multiple extreme environments at the same time, especially radiation, high temperature, air friction, etc. Since thermal insulation coatings generally use resin components, the coating surface will turn black when facing these environments, which will affect the various performance of the aircraft to varying degrees. Therefore, a single thermal insulation performance is often unable to fully protect the overall structure of the aircraft.

[0025] In response to the above-mentioned problems of the prior art, in the first aspect of the present application, a low-absorption and high-emission thermal insulation coating is provided, comprising a polymer binder, an inorganic functional filler, hollow microspheres, reinforcing fibers, an organic solvent and a curing agent; the hollow microspheres comprise first hollow microspheres with a diameter of 100-120 μm and second hollow microspheres with a diameter of 10-20 μm; the inorganic functional filler comprises a first inorganic functional filler with a particle size of 4-6 μm and a second inorganic functional filler with a particle size of 0.3-0.7 μm.

[0026] In the coating provided in the present application, the added large-sized hollow microspheres of 100-120 μm can improve the thermal insulation capacity of the coating, and the small-sized hollow glass microspheres of 10-20 μm can be filled between the large-sized hollow microspheres, which can reduce the fluidity of the large hollow microspheres and improve the compressive resistance and thermal insulation capacity; the two sizes of added inorganic functional fillers can be filled into the gaps between the hollow microspheres, further reducing the fluidity of the two sizes of hollow microspheres and enhancing the compressive resistance and stability of the coating; among them, the inorganic functional filler with a particle size of 0.3-0.7 μm has excellent light scattering ability and can improve the thermal control performance of the coating. In order to improve the problem of poor fluidity of small-sized inorganic functional fillers, inorganic functional fillers with a particle size of 4-6 μm are added to improve the overall fluidity, so that they can be better filled into the gaps between the hollow microspheres, thereby ensuring the stability and compressive resistance of the hollow microspheres.

[0027] At the same time, the lightweight fillers, such as hollow microspheres and reinforcing fibers, used in the coating of this application effectively reduce the weight of the coating. The hollow microspheres not only provide thermal insulation but, due to the different internal and external media of the hollow microspheres, also refract light secondary, reducing the coating's absorptivity. The reinforcing fibers also improve the coating's resistance to shear and aerodynamic erosion. The inorganic functional fillers, such as zinc oxide, used in this application not only have excellent light reflectivity but also possess thermal and chemical stability, improving the coating's high-temperature resistance.

[0028] In certain embodiments of the present application, the mass ratio of the first hollow microspheres to the second hollow microspheres is (2.5-3.5): (0.5-1.5), and they can be hollow microspheres of the same material or hollow microspheres of different materials; the mass ratio of the first inorganic functional filler to the second inorganic functional filler is (1.5-2.5): (0.5-1.5), and they can be the same inorganic functional fillers or different inorganic functional fillers.

[0029] In certain embodiments of the present application, the low-absorption, high-emission thermal insulation coating comprises, in parts by weight, typically in grams, 10-100 parts of a polymer binder, 20-150 parts of an inorganic functional filler, 8-90 parts of hollow microspheres, 10-50 parts of reinforcing fibers, 10-150 parts of an organic solvent, and a curing agent accounting for 1-10% of the mass of the polymer binder. Among them, the polymer binder can be 10 parts, 20 parts, 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, 80 parts, 90 parts, 100 parts, etc., the inorganic functional filler can be 20 parts, 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, 80 parts, 90 parts, 100 parts, 110 parts, 120 parts, 130 parts, 140 parts, 150 parts, etc., the hollow microspheres can be 8 parts, 10 parts, 13 parts, 18 parts, 20 parts, 23 parts, 30 parts, 40 parts, 50 parts , 60 parts, 70 parts, 80 parts, 90 parts and so on, the reinforcing fiber can be 10 parts, 20 parts, 30 parts, 40 parts, 50 parts and so on, the organic solvent can be 10 parts, 20 parts, 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, 80 parts, 90 parts, 100 parts, 110 parts, 120 parts, 130 parts, 140 parts, 150 parts and so on, the curing agent can account for 1% by mass of the polymer binder, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% and so on.

[0030] In some other embodiments of the present application, the length of the reinforcing fiber is 80-300 μm, and further optionally 150-250 μm.

[0031] In certain embodiments of the present application, the polymer binder includes one or more of methyl diphenyl silicone rubber, methyl phenyl vinyl silicone rubber, epoxy modified silicone resin, pure silicone resin, and phenolic resin; the inorganic functional filler includes one or more of ZnO, TiO2, ZrO2, and Zn2TiO4; the reinforcing fiber includes one or more of glass fiber, phenolic fiber, and aluminum silicate fiber; the organic solvent includes one or more of xylene, butyl acetate, and n-heptane; the hollow microspheres are Hollow microspheres of oxygen material, such as hollow glass microspheres, hollow ceramic microspheres; the curing agent is selected from tetraethyl orthosilicate, dibutyltin dilaurate, hydroxy silicone oil, bis(25) vulcanizer, hexamethylenetetramine and silane coupling agent according to the type of polymer, for example, tetraethyl orthosilicate and dibutyltin dilaurate can be selected for methyl diphenyl silicone rubber and pure silicone resin, hydroxy silicone oil and bis(25) vulcanizer can be selected for methyl phenyl vinyl silicone rubber, silane coupling agent (kh series) can be selected for epoxy modified silicone resin, and hexamethylenetetramine can be selected for phenolic resin.

[0032] The hollow microspheres and reinforcing fiber components specifically selected in this application contain a large number of oxygen atoms, which will release oxygen atoms during the thermal decomposition process. They have the ability to provide oxygen atoms and can provide an oxygen source for inorganic functional fillers such as ZnO, thereby reducing the oxygen escape and decomposition of inorganic functional fillers such as ZnO caused by space radiation, and preventing the degradation of the thermal control performance of the filler.

[0033] In certain embodiments of the present application, the coating may be any one of the following: (1)

[0035] Polymer binder 10-50g methyl bisphenyl silicone rubber

[0036] Organic solvent 10-40g xylene

[0037] Inorganic functional filler 20-60g ZnO (5μm:0.5μm=2:1)

[0038] Hollow microspheres 8-23g hollow glass microspheres (100μm:20μm=3:1)

[0039] Reinforcement fiber 10-50g glass fiber with a length of 150-250μm

[0040] Curing agent dibutyltin dilaurate (binder 3%) and tetraethyl orthosilicate (binder 6%) (2)

[0042] Polymer binder 60-90g methylphenyl vinyl silicone rubber

[0043] Organic solvent 40-80g butyl acetate

[0044] 30-80g of TiO2 (5μm:0.5μm=2:1) as inorganic functional filler

[0045] Hollow microspheres 40-80g hollow ceramic microspheres (100μm:20μm=3:1)

[0046] Reinforcement fiber 20-40g, aluminum silicate fiber length 150-250μm, curing agent hydroxy silicone oil (binder 8%) and dipentadiene disulfide vulcanizing agent (binder 1%) (3)

[0048] Polymer binder 50-100g epoxy modified silicone resin

[0049] Organic solvent 60-120g butyl acetate

[0050] Inorganic functional filler 90-140g ZnO (5μm:0.5μm=2:1)

[0051] Hollow microspheres 40-90g hollow glass microspheres (120μm:10μm=3:1)

[0052] Reinforcement fiber 30-50g phenolic fiber with a length of 150-250μm

[0053] Curing agent silane coupling agent (binder 2%) (4)

[0055] 40-80g polymer binder pure silicone resin

[0056] Organic solvent 60-100g xylene

[0057] Inorganic functional filler 30-60g of Zn2TiO4 and ZnO (5μm:0.5μm=2:1)

[0058] Hollow microspheres 40-90g hollow glass microspheres (100μm:20μm=3:1)

[0059] Reinforcement fiber 10-40g glass fiber with a length of 150-250μm

[0060] Curing agent dibutyltin dilaurate (binder 3%) and tetraethyl orthosilicate (binder 6%) (5)

[0062] Polymer binder 50-100 phenolic resin

[0063] Organic solvent 40-80g xylene

[0064] 50-80g of inorganic functional filler Zn2TiO4 (5μm:0.5μm=2:1)

[0065] Hollow microspheres 40-90g hollow glass microspheres (100μm:20μm=3:1)

[0066] Reinforcement fiber 30-50g glass fiber with a length of 150-250μm

[0067] Curing agent hexamethylenetetramine (binder 5%)

[0068] In a second aspect of the present application, a method for preparing the low-absorption, high-emission thermal insulation coating is provided, comprising:

[0069] S1. The polymer binder is dissolved and dispersed in an organic solvent to prepare a solution A;

[0070] S2. An inorganic functional filler was added to the solution A and stirred to mix to prepare a solution B;

[0071] S3. The hollow microspheres and reinforcing fibers were added to the solution B, and then stirred to prepare a solution C;

[0072] S4. Add a curing agent to the solution C, stir and mix evenly to prepare a low-absorption and high-emission thermal insulation coating.

[0073] In certain embodiments of the present application, glass beads may be added in step S2 to assist in stirring.

[0074] In a third aspect, the present application provides the use of the low-absorption, high-emissivity, thermal-insulating coating described herein for preparing a coating and substrate having low-absorption, high-emissivity, and thermal-insulating properties. The coating formed from the coating described herein has a solar absorptivity of 0.17-0.20, a hemispherical emissivity of 0.86-0.87, a thermal conductivity of 0.18-0.22 W / (m·K), a tensile strength through the coating thickness of 1.5-2.0 MPa, and an intact surface with no cracking or flaking, as measured by a 600°C quartz lamp for 10 minutes.

[0075] In the fourth aspect of the present application, a coating with low absorption, high emission and thermal insulation properties is provided, which is formed by drying the low-absorption, high-emission thermal insulation coating described in the present application. In certain embodiments of the present application, the present application uses a spraying process to apply the low-absorption, high-emission thermal insulation coating on a substrate such as an aluminum alloy or a titanium alloy to prepare a low-absorption, high-emission thermal insulation coating. More specifically, a 2.0 spray gun is used to spray a 0.5 mm thick low-absorption, high-emission thermal insulation coating on a metal test piece such as an aluminum alloy or a titanium alloy, and the coating is dried by baking at 60-150°C for 8-24 hours.

[0076] In the fifth aspect of the present application, a substrate with low absorption, high emission and heat insulation performance is also provided, comprising a substrate and the coating described in the present application coated on the surface of the substrate.

[0077] In certain embodiments of the present application, the substrate is a metal, such as the aforementioned aluminum alloy, titanium alloy, and other metal substrates.

[0078] In the comparative experiments provided in this application, unless otherwise specified, all experimental conditions and materials, except for the differences noted in each group, were kept consistent to ensure comparability. In addition, all materials used in this application can be purchased from commercial sources.

[0079] The following further describes a low-absorption, high-emission thermal insulation coating provided in this application, as well as its preparation method and application.

[0080] Example 1:

[0081] Weigh 10-50 g of methylbisphenyl silicone rubber in a beaker, pour in 10-40 g of xylene, stir to dissolve, add 20-60 g of ZnO of different particle sizes (5 μm:0.5 μm=2:1), 50-70 g of glass beads, and then stir on a stirrer with a four-blade stirring paddle at 1200 r / min for 2 h. After stirring evenly, the glass beads were filtered out with an 80-mesh copper mesh, and 8 to 23 g of hollow SiO2 glass microspheres (100 μm: 20 μm = 3:1) and 10 to 50 g of glass fibers with a length of 150 to 250 μm were added to the filtered solution. The mixture was stirred at a stirring speed of 500 r / min for 3 h, and a curing agent consisting of dibutyltin dilaurate (binder 3%) and ethyl orthosilicate (binder 6%) was added to prepare a low-absorption and high-emission thermal insulation coating. A 2.0 spray gun was used to spray a 0.5 mm thick low-absorption and high-emission thermal insulation coating on an aluminum alloy test piece, and the coating was dried by baking at 60 to 150 ° C for 8 to 24 h.

[0082] Coating performance test: After testing, the coating has a solar absorption ratio of 0.20, a hemispherical emissivity of 0.86, and a thermal conductivity of 0.18W / (m·K). The coating has a tensile strength of 2MPa in the thickness direction. After 10 minutes of 600℃ quartz lamp radiation heating, the surface is intact with no discoloration, cracking, or peeling. See the microscopic picture of the coating surface for details. Figure 1 , the visual pictures before and after the quartz lamp test are shown in Figure 2 .

[0083] Example 2:

[0084] Weigh 60-90 g of methylphenyl vinyl silicone rubber in a beaker, pour in 40-80 g of butyl acetate, stir to dissolve, add 30-80 g of TiO2 of different particle sizes (5 μm:0.5 μm=2:1), 80-120 g of glass beads, and then stir on a stirrer with a four-blade stirring paddle at 1200 r / min for 2 h. After stirring evenly, filter out the glass beads with an 80-mesh copper mesh, add 40-80g hollow ceramic microspheres (100μm:20μm=3:1) and 20-40g aluminum silicate fibers with a length of 150-250μm to the filtered solution, stir for 3h at a stirring speed of 500r / min, add hydroxyl silicone oil (binder 8%) and dipentadienyl vulcanizer (binder 1%) as curing agent, continue stirring for a few minutes to mix, and prepare a low-absorption and high-emission thermal insulation coating. Use a 2.0 spray gun to spray a 0.5mm thick low-absorption and high-emission thermal insulation coating on an aluminum alloy test piece, and bake it at 60-150℃ for 8-24h to dry.

[0085] Coating Performance Testing: After testing, the coating demonstrated a solar absorptivity of 0.19, a hemispherical emissivity of 0.87, and a thermal conductivity of 0.18 W / (m·K). The coating demonstrated a tensile strength of 1.7 MPa across the thickness direction. After 10 minutes of 600°C quartz lamp radiant heating, the surface remained intact, exhibiting no discoloration, cracking, or flaking. The coating's microscopic appearance and visual appearance before and after quartz lamp testing remained essentially consistent with those of Example 1.

[0086] Example 3:

[0087] Weigh 50-100g of epoxy-modified silicone resin in a beaker, pour in 60-120g of butyl acetate, stir to dissolve, add 90-140g of ZnO of different particle sizes (5μm:0.5μm=2:1), 120-180g of glass beads, and then stir on a stirrer with a four-blade stirring paddle at 1200r / min for 2h. After stirring evenly, filter out the glass beads with an 80-mesh copper mesh, add 40-90g hollow SiO2 glass microspheres (120μm:10μm=3:1) and 30-50g phenolic fiber with a length of 150-250μm into the filtered solution, stir for 3h at a stirring speed of 500r / min, add KH silane coupling agent (binder 2%) as a curing agent, continue stirring for a few minutes to mix, and prepare a low-absorption and high-emission thermal insulation coating. Use a 2.0 spray gun to spray a 0.5mm thick low-absorption and high-emission thermal insulation coating on an aluminum alloy test piece, and bake it at 60-150℃ for 8-24h to dry.

[0088] Coating Performance Testing: After testing, the coating demonstrated a solar absorptivity of 0.17, a hemispherical emissivity of 0.87, and a thermal conductivity of 0.22 W / (m·K). The coating demonstrated a tensile strength of 1.5 MPa across the thickness direction. After 10 minutes of 600°C quartz lamp heating, the surface remained intact, exhibiting no discoloration, cracking, or flaking. The coating's microscopic appearance and visual appearance before and after the quartz lamp test remained essentially consistent with those of Example 1.

[0089] Example 4:

[0090] Weigh 40-80g of pure silicone resin in a beaker, pour in 60-100g of xylene, stir to dissolve, add 30-60g of mixed powder of Zn2TiO4 and ZnO (mass ratio 2:1) of different particle sizes (5μm:0.5μm=2:1), 70-110g of glass beads, and then stir on a stirrer with a four-blade stirring paddle at 1200r / min for 2h. After stirring evenly, filter out the glass beads with an 80-mesh copper mesh, add 40-90g hollow glass microspheres (100μm:20μm=3:1) and 10-40g quartz glass fiber with a length of 150-250μm to the filtered solution, stir at a stirring speed of 500r / min for 3h, add dibutyltin dilaurate (binder 3%) and ethyl orthosilicate (binder 6%) as curing agent, continue stirring for a few minutes to mix, and prepare a low-absorption and high-emission thermal insulation coating. Use a 2.0 spray gun to spray a 0.5mm thick low-absorption and high-emission thermal insulation coating on an aluminum alloy test piece, and bake it at 60-150℃ for 8-24h to dry.

[0091] Coating Performance Testing: After testing, the coating demonstrated a solar absorptivity of 0.17, a hemispherical emissivity of 0.87, and a thermal conductivity of 0.22 W / (m·K). The coating demonstrated a tensile strength of 1.5 MPa across the thickness direction. After 10 minutes of 600°C quartz lamp heating, the surface remained intact, exhibiting no discoloration, cracking, or flaking. The coating's microscopic appearance and visual appearance before and after the quartz lamp test remained essentially consistent with those of Example 1.

[0092] Example 5:

[0093] Weigh 50-100g of phenolic resin in a beaker, pour in 40-80g of xylene, stir to dissolve, add 50-80g of Zn2TiO4 of different particle sizes (5μm:0.5μm=2:1), 70-100g of glass beads, and then stir on a stirrer with a four-blade stirring paddle at 1200r / min for 2h. After stirring evenly, filter out the glass beads with an 80-mesh copper mesh, add 40-90g hollow glass microspheres (100μm:20μm=3:1) and 30-50g glass fibers with a length of 150-250μm into the filtered solution, stir for 3h at a stirring speed of 500r / min, add hexamethylenetetramine (5% binder) as a curing agent, and prepare a low-absorption and high-emission thermal insulation coating. Use a 2.0 spray gun to spray a 0.5mm thick low-absorption and high-emission thermal insulation coating on an aluminum alloy test piece, and bake it at 60-150℃ for 8-24h to dry.

[0094] Coating Performance Testing: After testing, the coating demonstrated a solar absorptivity of 0.17, a hemispherical emissivity of 0.87, and a thermal conductivity of 0.22 W / (m·K). The coating demonstrated a tensile strength of 1.5 MPa across the thickness direction. After 10 minutes of 600°C quartz lamp heating, the surface remained intact, exhibiting no discoloration, cracking, or flaking. The coating's microscopic appearance and visual appearance before and after the quartz lamp test remained essentially consistent with those of Example 1.

[0095] Comparative Example 1:

[0096] Based on the process of Example 1, only hollow SiO2 glass microspheres with a diameter of 100 μm were used as hollow microspheres, and hollow SiO2 glass microspheres with a diameter of 20 μm were not used. The total amount of hollow microspheres remained unchanged, and the other components and amounts were consistent with Example 1 to prepare a coating.

[0097] Coating performance testing: After testing, the coating showed a solar absorptivity of 0.26, a hemispherical emissivity of 0.89, and a thermal conductivity of 0.26 W / (m·K). The coating's tensile strength through the thickness direction was 1.7 MPa. After 10 minutes of 600°C quartz lamp radiation heating, the coating surface showed little discoloration, with minor cracks and no peeling.

[0098] Comparative Example 2:

[0099] Based on the process of Example 1, only hollow SiO2 glass microspheres with a diameter of 20 μm were used, and hollow SiO2 glass microspheres with a diameter of 100 μm were not used. The total amount of hollow microspheres remained unchanged, and other components and amounts were consistent with Example 1 to prepare a coating.

[0100] Coating performance testing: After testing, the coating showed a solar absorptivity of 0.29, a hemispherical emissivity of 0.88, and a thermal conductivity of 0.27 W / (m·K). The coating's tensile strength through the thickness direction was 1.1 MPa. After 10 minutes of 600°C quartz lamp radiation heating, the coating surface was slightly blackened, with cracks present, but no peeling.

[0101] Comparative Example 3:

[0102] Based on the process of Example 1, only ZnO with a particle size of 5 μm was used, and ZnO with a particle size of 0.5 μm was not used. The total amount of inorganic functional filler remained unchanged, and other components and amounts were consistent with Example 1 to prepare a coating.

[0103] Coating performance testing: After testing, the coating showed a solar absorptivity of 0.25, a hemispherical emissivity of 0.88, and a thermal conductivity of 0.34 W / (m·K). The coating's tensile strength through the thickness direction was 1.8 MPa. After 10 minutes of 600°C quartz lamp radiation heating, the coating showed little discoloration, with only minor flaking.

[0104] Comparative Example 4:

[0105] Based on the process of Example 1, only ZnO with a particle size of 0.5 μm was used, and ZnO with a particle size of 5 μm was not used. The total amount of inorganic functional filler remained unchanged, and other components and amounts were consistent with Example 1 to prepare a coating.

[0106] Coating performance testing: After testing, the coating showed a solar absorptivity of 0.18, a hemispherical emissivity of 0.87, and a thermal conductivity of 0.38 W / (m·K). The coating's tensile strength through the thickness direction was 1.5 MPa. After 10 minutes of 600°C quartz lamp radiation heating, the coating showed little discoloration, but exhibited significant flaking.

[0107] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A low-absorption, high-emission thermal insulation coating, characterized in that: The invention comprises a high-temperature resistant polymer binder, an inorganic functional filler, hollow microspheres, reinforcing fibers, an organic solvent and a curing agent; the hollow microspheres comprise first hollow microspheres with a diameter of 100-120 μm and second hollow microspheres with a diameter of 10-20 μm; the inorganic functional filler comprises a first inorganic functional filler with a particle size of 4-6 μm and a second inorganic functional filler with a particle size of 0.3-0.7 μm.

2. The low-absorption and high-emission thermal insulation coating according to claim 1, characterized in that: The invention comprises, by weight, 10-100 parts of a high-temperature resistant polymer binder, 20-150 parts of an inorganic functional filler, 8-90 parts of hollow microspheres, 10-50 parts of reinforcing fibers, 10-150 parts of an organic solvent and a curing agent accounting for 1-10% of the mass of the high-temperature resistant polymer binder.

3. The low-absorption and high-emission thermal insulation coating according to claim 1 or 2, characterized in that: The high-temperature resistant polymer binder includes one or more of methyl diphenyl silicone rubber, methyl phenyl vinyl silicone rubber, epoxy modified silicone resin, pure silicone resin, and phenolic resin; the inorganic functional filler includes one or more of ZnO, TiO2, ZrO2, and Zn2TiO4; the hollow microspheres are hollow microspheres made of oxygen-containing materials; the reinforcing fibers include one or more of glass fiber, phenolic fiber, and aluminum silicate fiber; the organic solvent includes one or more of xylene, butyl acetate, and n-heptane; and the curing agent is selected from tetraethyl orthosilicate, dibutyltin dilaurate, hydroxy silicone oil, dipentadienyl vulcanizer, hexamethylenetetramine, and silane coupling agent according to the type of polymer.

4. The method for preparing the low-absorption and high-emission thermal insulation coating according to claim 1, characterized in that: include: S1. The high temperature resistant polymer binder is poured into an organic solvent and dissolved and dispersed to prepare a solution A; S2. An inorganic functional filler was added to the solution A and stirred to mix to prepare a solution B; S3. The hollow microspheres and reinforcing fibers were added to the solution B, and then stirred to prepare a solution C; S4. Add a curing agent to the solution C, stir and mix evenly to prepare a low-absorption and high-emission thermal insulation coating.

5. Use of the low-absorption, high-emission thermal insulation coating according to any one of claims 1 to 3 in the preparation of coatings and substrates with low absorption, high emission and thermal insulation properties.

6. A coating with low absorption, high emission and heat insulation properties, characterized in that: The low-absorption and high-emission thermal insulation coating is formed by drying the low-absorption and high-emission thermal insulation coating according to any one of claims 1 to 3.

7. A substrate with low absorption, high emission and heat insulation properties, characterized in that: The invention comprises a substrate, and the coating according to claim 6 coated on the surface of the substrate.

8. The substrate according to claim 7, characterized in that The substrate is metal.

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