Application of high refractive index glass microspheres, infrared reflective coating using the same and preparation method thereof

Abstract

The present invention discloses an application of high-refractive index glass microspheres, an infrared reflective coating using the same, and a preparation method thereof. The application of the high-refractive index glass microspheres of the present invention improves the brightness and infrared reflective performance of the coating by adding high-refractive index glass microspheres to the infrared reflective coating; the infrared reflective coating includes a primer, a middle coating, and a top coating from bottom to top; wherein all coatings are made of a mixture of transparent high-refractive index glass microspheres and a base material; high-refractive index glass microspheres and non-circular cold colored sand or infrared reflective microspheres are added to the top coating base material, and the surface of the top coating is embedded with high-refractive index glass microspheres. The present invention adds high-refractive index glass microspheres to the infrared reflective coating to achieve the effect of improving the brightness of the infrared reflective coating, and after using the high-refractive index glass microspheres as a brightness improvement regulator, the hemispherical emissivity, total solar heat reflectivity, and near-infrared reflectivity of the infrared reflective coating can be greatly improved, thereby achieving the purpose of building energy saving.

Description

Technical Field

[0001] The present invention belongs to the field of building energy conservation, and specifically relates to the field of infrared reflective pigments and solar reflective heat-insulating coatings, and particularly relates to the application of high-refractive index glass microspheres, infrared reflective coatings using the same, and a preparation method thereof. Background Art

[0002] Water-based building solar reflective heat-insulating paint is also called water-based building infrared reflective heat-insulating paint (abbreviated as: infrared reflective heat-insulating paint or solar reflective heat-insulating paint. After the paint coating is dried, it is called: infrared reflective heat-insulating coating or solar reflective heat-insulating coating). The coating can reflect and radiate the energy of solar radiation. Infrared reflective water-based heat-insulating paint is based on synthetic resin and water as the dispersion medium. The reflective function is mainly achieved by adding infrared reflective pigments and other auxiliary materials, and it is a new type of functional paint made through a certain process. Infrared reflective topcoats are divided into flat coating type and texture type (texture is divided into "real stone particle texture type" and "powder thick coating texture type"). The texture type is more difficult to achieve solar infrared reflection effect than the flat coating type.

[0003] Infrared reflective pigment (IR pigment for short) is a pigment that can reflect light in the visible light region, absorb light in the ultraviolet region, transmit light in the infrared region, or any combination of the three. In this way, they have a certain color, even a darker color, and can reflect part of the infrared light, reduce the accumulation of heat, and play a cooling role. We call the pigment that has a certain color in the visible light region and has the ability to reflect infrared light in the infrared region "infrared reflective pigment". Infrared reflective pigment can give any color of coating or polymer products the ability to reflect sunlight.

[0004] As far as the reflective performance of infrared reflective pigments at home and abroad is concerned, the best reflective effect is titanium dioxide (which is further subdivided into ordinary titanium dioxide and high refractive index titanium dioxide, also known as reflective titanium dioxide). The total reflectance (TSR) of sunlight can reach up to 90% for white flat paint mixed with ordinary titanium dioxide and reflective titanium dioxide; the total reflectance (TSR) of sunlight for white real stone paint textured paint will drop by about 10%, and can reach up to about 80%. It will be difficult to increase it further, and even if it is increased, the range is limited. The solar reflective heat insulation performance of the coating is currently characterized by measuring the solar reflectance of the coating after the dry film is dried using special instruments (mainly measuring the three indicators of total solar heat reflectance (TSR), near infrared reflectance (NIR) and hemispherical emissivity). White reflects all bands of light, including visible light and infrared light. But in fact, the exterior walls and roofs of buildings are not all white. A large number of experiments have confirmed that the addition of color pigments to coatings has the greatest (negative) impact on the reflectance of sunlight. At present, the reflectivity of any color to sunlight cannot be as high as that of white, and after adding it, the reflectivity of the coating to sunlight will drop significantly.

[0005] Some well-known architectural research institutes and colored sand manufacturing companies at home and abroad have made "cold colored sand" by coating the outer surface of irregular white sand particles with infrared reflective pigments (the United States calls infrared reflective pigments "cold pigments". The artificial synthetic colored sand made from it is called "non-circular real stone cold colored sand" in China, or "cold colored sand" for short). Since the surface of most natural colored stone particles is irregular and porous, it is difficult to form a gathering and mirror reflection effect on visible light when sunlight shines on it, and it is also difficult to form an effective reflection of infrared light.

[0006] The solar reflectivity of "infrared reflective thermal insulation real stone paint coating" was tested against GB / T 25261-2018 "Reflective thermal insulation coating for buildings" and JG / T 235-2014 "Reflective thermal insulation coating for buildings". Except for some white colors, most colored real stone paint coatings are difficult to meet the standards, especially high-brightness multi-colored real stone paint coatings. In order to meet the so-called "standard" of coating performance, a few manufacturers deliberately lower the brightness of infrared reflective coatings to reduce the total solar reflectance (TSR) to meet the standards. This practice violates the purpose of using reflective thermal insulation coatings for building energy conservation.

[0007] from Figure 3 GB / T 25261-2018 "Reflective thermal insulation coatings for buildings" and Figure 4From the two standards of JG / T 235-2014 "Architectural Reflective Thermal Insulation Coatings", it can be seen that the total solar reflectance (TSR) and near-infrared reflectance (NIR) are directly correlated with the brightness of the reflective coating. That is, in most cases, if the brightness of the infrared reflective coating is increased, the infrared reflective performance of the coating will also be improved accordingly; if the brightness of the reflective coating is reduced, the infrared reflective performance of the coating will also be reduced accordingly.

[0008] At present, the mainstream and mature solar wave radiation and infrared reflective coating technology in the world mainly relies on "infrared reflective pigments and fillers" to achieve its reflective radiation effect. The infrared reflective performance of each infrared reflective pigment is basically fixed due to its fixed composition ratio. When mixing infrared reflective coatings, if the pigment is not properly selected (such as adding carbon black, iron black and other high infrared absorption materials), the infrared reflective performance will not only not increase, but will decrease significantly. When the performance of infrared reflective pigments is fixed and cannot be improved, we can only seek new "filler technology" and make new breakthroughs to achieve the final desired products and goals. Summary of the invention

[0009] In view of the above problems, the present invention provides an application of high-refractive index glass microspheres, an infrared reflective coating using the same and a preparation method thereof; the present invention selects special functional fillers such as high-refractive index glass microspheres and infrared reflective microspheres, and cleverly designs and distributes them in the coating: sunlight (mainly visible light, infrared light and ultraviolet light) is irradiated into the transparent or translucent coating surface coating, the middle coating and even the base coating, the sunlight is reflected back when encountering obstacles, and is directionally retro-reflected and refracted inside the coating, illuminating the middle coating and the surface coating from the inside, thereby achieving the effect of improving the brightness of the coating. The improvement of the coating brightness, coupled with the use of infrared reflective pigments and infrared reflective microspheres, can comprehensively improve the infrared reflection performance of the coating.

[0010] The present invention is achieved through the following technical solutions:

[0011] The present invention provides an application of high-refractive-index glass microspheres, which improves the brightness and infrared reflection performance of the coating by adding high-refractive-index glass microspheres to the infrared reflection coating;

[0012] The infrared reflective coating includes a base coat, a middle coat and a top coat from bottom to top; wherein all the coatings are made of transparent high-refractive index glass microspheres mixed with a base material, high-refractive index glass microspheres and non-circular cold colored sand or infrared reflective microspheres are added to the base material of the top coat at a mass ratio of 1:1, and 15%-25% of the coating area of ​​the top coat is embedded with high-refractive index glass microspheres;

[0013] The high refractive index glass microspheres refer to glass microspheres with a refractive index greater than Transparent optical microspheres or nearly spherical bodies;

[0014] The particle size of the high refractive index glass microspheres used is any single narrow particle size of 0 to 4000 μm or a wide particle size group composed of a physical mixture of multiple particle sizes.

[0015] Furthermore, the high refractive index glass microspheres used preferably have a particle size of any single narrow particle size of 10-1000 μm and a wide particle size group composed of a physical mixture of multiple particle sizes.

[0016] Furthermore, the high refractive index glass microspheres refer to transparent optical microspheres or approximately spherical microspheres with a refractive index of 1.93±0.005.

[0017] For ultra-fine glass microspheres <120 mesh, due to the limitation of solid materials and physical sieve technology, it is impossible to obtain "microspheres of any single particle size group" with 100% accuracy, and only "microspheres of an approximate single narrow particle size group" can be obtained. In the actual manufacturing process, as long as the particle size of the microspheres at the upper and lower ends can be controlled to account for <5% of the total microsphere mass, and the middle main "narrow particle size microspheres" account for ≥95% of the total microsphere mass, the use requirements can be basically met.

[0018] More specifically, high refractive index glass microspheres refer to high refractive index glass microspheres made of TiO2-BaO-SiO2-Al2O3 or BaO-SiO2-TiO2 or other formulas, with the number of microspheres visually observed being equal to or not less than 150 within a field of view of an optical microscope of about 20-40 times, the total number of defective microspheres being less than 5% of the statistical total number, the roundness being ≥95%, the devitrification being <3%, and the specific gravity being 4.2±0.1 g / cm3; defective microspheres refer to glass microspheres with defects, crystallization, debris, impurities, bubbles, streaks, etc.

[0019] In addition to the original transparency of glass, the high refractive index glass microspheres also have directional reflective and retroreflective properties (due to the uniform spherical characteristics of the microspheres, after the light enters the sphere, it will be refracted, and part of the light will return along the original path, which is commonly known as "retroreflection"). The high refractive index glass microspheres have certain chemical stability, mechanical strength, electrical insulation, and the characteristics of roundness, uniformity, and good flow.

[0020] The infrared reflective pigment and high refractive index glass microspheres for improving the brightness of solar reflective paint of the present invention are prepared in accordance with the process formula, method and steps of "non-circular cold colored sand + high refractive index glass microspheres" or "infrared reflective microspheres + high refractive index glass microspheres" to obtain the paint and coating layer in sequence. The top coating layer and the middle coating layer of the coating are designed with a directional optical retro-propagation channel for sunlight to be irradiated, and the sunlight is directly irradiated into the transparent or translucent top coating layer and the middle coating layer until the bottom coating layer, and there are retro-reflection and refraction phenomena.

[0021] The high-refractive-index glass microspheres of the present invention are used as infrared reflective pigments and solar infrared reflective coating brightness enhancing regulators to prepare infrared reflective coatings, which have a structure comprising an aluminum plate, a primer layer, a mid-coat layer, a top-coat layer sequentially coated and cured thereon, and high-refractive-index glass microspheres embedded in the top-coat layer;

[0022] The base coating material comprises a base material for the base coating material, ordinary titanium dioxide and reflective titanium dioxide, and the base coating film thickness is 40-100 μm;

[0023] The middle coating comprises a base material for the middle coating and high-refractive index glass microspheres, and the middle coating has a film thickness of 400-600 μm;

[0024] The surface coating paint comprises a surface coating base material, high-refractive index glass microspheres and non-circular cold colored sand or infrared reflective microspheres, the surface coating film thickness is 400-500 μm; the dry film thickness of the protruding part of the surface coating is 50-200 μm;

[0025] The base materials for each coating are independently selected from the following compositions in the following mass parts:

[0026]

[0027] The mass fraction of common titanium dioxide in the base coating is 1-50, and the mass fraction of reflective titanium dioxide is 2-100, which is consistent with the mass fraction in the base material for the base coating;

[0028] The mass fraction of non-circular cold colored sand or infrared reflective microspheres in the top coating is 100-800, and the mass fraction of high refractive index glass microspheres is 100-800, which is consistent with the mass fraction benchmark in the top coating base material;

[0029] The mass fraction of high refractive index glass microspheres in the mid-coat coating is 100-800, which is consistent with the mass fraction benchmark in the base material for the mid-coat;

[0030] The high refractive index glass microspheres embedded in the surface coating account for 15%-25% of the surface coating area. The embedding depth is determined by the actual scraping operation so that the microspheres are partially submerged by the resin without falling off. The embedding depth of the high refractive index glass microspheres is 1 / 3 to 1 / 2 of their particle size.

[0031] The non-circular cold colored sand is prepared by using non-circular irregular siliceous sand or calcareous sand mineral particles with a particle size greater than 200 meshes, coating the outer surface of the particles with infrared reflective pigments and organic / inorganic adhesives, and using a high-temperature sintering method / chemical cross-linking method to obtain the non-circular infrared reflective colored sand, also known as non-circular cold colored sand;

[0032] The infrared reflective microspheres are prepared by using transparent, spherical silicate glass microspheres with a particle size of less than 4000 μm as a substrate, wrapping infrared reflective pigments and organic / inorganic adhesives on the outer surface of the glass microspheres, and using a high-temperature sintering method / chemical cross-linking method to obtain solar thermal radiation infrared reflective microspheres, referred to as infrared reflective microspheres.

[0033] The particle size of the non-circular cold colored sand is selected from one of 200-120 mesh, 120-80 mesh, and 80-40 mesh; the particle size of the infrared reflective microsphere corresponds to the particle size of the non-circular cold colored sand, and is selected from one of 160 mesh, 100 mesh, and 60 mesh.

[0034] When non-circular cold colored sand is used in the top coating, the particle size of the high refractive index glass microspheres used in the middle coating is selected from one of 200-120 mesh, 120-80 mesh, and 80-40 mesh, the particle size of the high refractive index glass microspheres embedded in the top coating is selected from one of 200-120 mesh, 120-80 mesh, and 80-40 mesh, and the final total thickness of the infrared reflective coating is 1000-1500 μm;

[0035] When infrared reflective microspheres are used in the top coating, the particle size of the high refractive index glass microspheres used in the middle coating is selected from one of the corresponding 160 mesh, 100 mesh, and 60 mesh, and the particle size of the high refractive index glass microspheres embedded in the top coating is selected from one of the corresponding 160 mesh, 100 mesh, and 60 mesh, and the final total film thickness of the infrared reflective coating is 800-1300 μm.

[0036] The method for preparing an infrared reflective coating using the high refractive index glass microspheres of the present invention as infrared reflective pigments and a brightness enhancing regulator for solar reflective heat-insulating coatings comprises the following specific steps:

[0037] (1) Preparation of the base coating: the silicone-modified acrylic emulsion in the base material is weighed and poured into a stirring container, and then other components of the base material are added and stirred at 500-1200 rpm for 30 minutes to prepare the base material for the base coating; then ordinary titanium dioxide and reflective titanium dioxide are added to the base material, dispersed and stirred evenly to prepare the base coating; and the base coating is applied on an aluminum plate with a size of 100×80×1.0 mm, and the base coating film is dried and hardened for standby use;

[0038] (2) Preparation of topcoat coating: weigh the organosilicon-modified acrylic emulsion in the base material and pour it into a stirring container, then add other components of the base material and stir at 500-1200 rpm for 30 minutes to prepare the base material for the topcoat coating; then add non-circular cold colored sand or infrared reflective microspheres, high refractive index glass microspheres into the base material and mix them evenly to prepare the topcoat coating;

[0039] (3) Preparation of high-refractive and retro-transparent mid-coat paint: weigh the organosilicon-modified acrylic emulsion in the base material and pour it into a stirring container, then add other components of the base material and stir at 500-1200 rpm for 30 minutes to prepare the base material for the mid-coat paint; then add high-refractive index glass microspheres into the base material and mix well to prepare the high-refractive and retro-transparent mid-coat paint;

[0040] (4) firstly, the high-refractive and retro-transparent middle coating obtained in step (3) is evenly scraped on the aluminum plate coated with ordinary titanium dioxide and reflective titanium dioxide primer in step (1), and after the coating is dried, the infrared reflective top coating obtained in step (2) is evenly scraped on the high-refractive and retro-transparent middle coating;

[0041] (5) Before the infrared reflective surface coating in step (4) is cured, high-refractive-index glass microspheres accounting for 15% to 25% of the surface coating area are evenly spread on the surface, and embedded in non-circular cold colored sand or infrared reflective microspheres. The embedding depth is such that the microspheres are partially submerged by the resin during the actual scraping operation without falling off, that is, the embedding depth of the high-refractive-index glass microspheres is 1 / 3 to 1 / 2 of their particle size; then, the surface is scraped flat, and then heat-dried to obtain the infrared reflective coating of the present invention.

[0042] The principle of retro-reflection of high-refractive-index glass microspheres used in the present invention is as follows: high-refractive-index glass microspheres are an inorganic silicate material, and have good retro-reflection properties when the refractive index is between 1.9 and 2.1. That is, when a beam of light hits the surface of the glass microsphere at any angle within a certain range, the light is focused on a specific reflective layer behind the glass microsphere due to the refraction of the glass microsphere, and the reflective layer reflects the light back in parallel along the direction of the light source. Figure 1 This is a schematic diagram of the optical principle of glass microsphere refraction and regression reflection. Figure 1 Where O is the optical axis, i is the incident angle, θ is the refraction angle, θ' is the reflection angle, n is the refractive index of the glass microsphere, n o is the refractive index of air. When the incident angle i≠0, the conditions for retro-reflection can be determined according to the refraction theorem: n o sini=n.sinθ, due to n o =1, so sini = n sinθ, and from optical theory we can get i = 2θ, so the refractive index of the glass microsphere is n = 2cosθ. From the principle of optics we know that i≤90°, which means θ≤45°. Therefore, only when The glass microsphere will only reflect retro-reflection when the reflected light cannot be concentrated in a small angle cone, so the retro-reflection phenomenon of the glass microsphere is not obvious. After the glass microspheres are refracted, there are three focusing situations depending on the refractive index:

[0043] (1) Refractive index When , the focus falls outside the glass microsphere;

[0044] (2) When n = 1.93, the focus falls on the inner surface of the glass microsphere;

[0045] (3) When the refractive index n>1.93, the focus falls on the glass microsphere;

[0046] We can also apply the thick lens formula (1) to the glass microsphere to analyze the retro-reflection characteristics of the glass microsphere. F = nr / 2(n-1)(1) In the formula, F is the focal length; n is the refractive index of the glass microsphere; and r is the diameter of the glass microsphere. For light passing near the center of the glass microsphere, when n = 2, F = r, so the focus is on the back of the glass microsphere, and it can show complete retro-reflection characteristics. However, due to the influence of spherical aberration, the light passing through the periphery is refracted greatly. Therefore, for the light passing 37° from the center, when n = 1.9, its focus is on the back of the glass microsphere, and it can show complete retro-reflection characteristics. From the above-mentioned retro-reflection principle of glass microspheres, it can be seen that the retro-reflection characteristics of glass microspheres are related to the refractive index of glass as follows: When As the refractive index n of the glass microsphere increases, the closer the reflected light is to the optical axis, the smaller the angle cone is, so the retro-reflective performance is better. It is generally believed that glass microspheres with n=1.93 can obtain the best retro-reflective performance because the focus of light falls on the inner surface of the microsphere.

[0047] It should be pointed out that glass microspheres with a refractive index lower than 1.93 and greater than 1.93 also have high reflection and refraction properties and can be used in the field of infrared reflective heat insulation coatings. However, compared with glass microspheres with a refractive index equal to 1.93±0.005, they do not have a directional retro-reflection phenomenon, so the extent to which they improve the brightness of the coating is relatively reduced. The use of the above glass microspheres also belongs to the special functional fillers within the scope of the microspheres referred to in the present invention, and should be included in the protection scope of the present invention.

[0048] The high refractive index glass microspheres used as brightness regulators in the present invention are used in infrared reflective coatings to utilize the strong emission, high refraction, and retro-reflective characteristics of high refractive index glass microspheres in the visible light band, and the infrared reflective microsphere pigments and high refractive index glass microspheres are reasonably proportioned and made into coatings; when sunlight irradiates the coating surface, the coating with high refractive index glass microspheres has strong emission, high refraction, and retro-reflective characteristics, thereby achieving the effect of improving the brightness of infrared reflective coatings. After using the regulator, the infrared reflective performance of the pigment is still retained, and combined with the use of infrared reflective microsphere pigments, the hemispherical emissivity (HE), total solar heat reflectivity (TSR), and near infrared reflectivity (NIR) of solar reflective heat insulation coatings, especially real stone paint coatings, can be greatly improved, thereby achieving the purpose of building energy saving, and having broad application prospects. The infrared reflective coating prepared by the present invention has the significant effect of saving energy consumption of building refrigeration equipment and reducing the "heat island effect" of the city. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 Schematic diagram of the optical principle of glass microsphere refraction and retro-reflection (O is the optical axis, i is the incident angle, θ is the refraction angle, θ' is the reflection angle, n is the refractive index of the glass microsphere, and no is the refractive index of air).

[0050] Figure 2 This is a structural diagram of the infrared reflective coating using high-refractive index glass microspheres described in the present invention.

[0051] Figure 3 It meets the requirements of GB / T 25261-2018 "Reflective Thermal Insulation Coatings for Buildings".

[0052] Figure 4 It complies with the standard requirements of JG / T 235-2014 "Architectural Reflective Thermal Insulation Coatings".

[0053] Figure 2 The markings in the figure are: 1 external concrete wall or roof of the building, 2 base coating, 3 middle coating, 4 surface coating, 5 embedded high refractive index glass microspheres; those marked with "transparent" in 4 are high refractive index glass microspheres, and those marked with "color" are infrared reflective microspheres or non-circular cold colored sand. DETAILED DESCRIPTION

[0054] The present invention is further described below in conjunction with examples. The examples are only used to more clearly illustrate the technical solutions of the present invention, and the implementation methods are not limited thereto, and the protection scope of the present invention cannot be limited thereto.

[0055] Example 1

[0056] The steps for preparing the infrared reflective coating according to the process formula of "non-circular cold colored sand + high refractive index glass microspheres" (Formula 1) are as follows:

[0057] (1) Preparation of base coating: 50 g of organosilicon-modified acrylic emulsion was weighed and poured into a stirring container, 0.5 g of film-forming aid, 0.2 g of dispersant, 1.5 g of thickener, 0.15 g of curing agent, and 0.1 g of defoamer were added, and stirred at 500-1200 rpm for 30 minutes to prepare a base material for base coating; then 6 g of ordinary titanium dioxide and 12 g of reflective titanium dioxide were added to the base material, and the mixture was dispersed and stirred evenly to prepare a base coating; and the base coating was applied on an aluminum plate with a size of 100×80×1.0 mm, with a base coating film thickness of 50 μm. The film was dried and hardened for standby use;

[0058] (2) Preparation of infrared reflective surface coating: 60 g of silicone-modified acrylic emulsion was weighed and poured into a stirring container, 0.8 g of film-forming aid, 0.2 g of dispersant, 1.5 g of thickener, 0.2 g of curing agent, and 0.15 g of defoamer were added, and stirred at 500-1200 rpm for 30 minutes to prepare a base material for the surface coating; 200 g of 120-80 mesh yellow non-circular cold-colored sand and 200 g of 120-80 mesh high-refractive index glass microspheres were added to the base material, and mixed evenly to prepare a surface coating composed of 50% yellow non-circular cold-colored sand and 50% high-refractive index glass microspheres;

[0059] (3) Preparation of high-refractive and retro-transparent mid-coat paint: 150 g of silicone-modified acrylic emulsion was weighed and poured into a stirring container, and 1.5 g of film-forming aid, 0.6 g of dispersant, 4 g of thickener, 0.4 g of curing agent, and 0.3 g of defoamer were added, and stirred at 500-1200 rpm for 30 minutes to prepare a base material for the mid-coat paint; 800 g of high-refractive index glass microspheres with a refractive index of 1.93±0.005 and 120-80 mesh were added to the base material, and the mixture was mixed evenly to prepare a high-refractive and retro-transparent mid-coat paint;

[0060] (4) First, the high-refractive and retro-transparent middle coating obtained in step (3) is evenly scraped on an aluminum plate coated with ordinary titanium dioxide and reflective titanium dioxide primer, the size of which is 100×80×1.0 mm; after the coating is surface-dried (the film thickness of this layer after surface drying is about 800 μm), the mixed top coating obtained in step (2) is evenly scraped on the high-refractive and retro-transparent middle coating, and the film thickness of this layer after surface drying is about 400 μm;

[0061] (5) Before the top coating of step (4) is cured, 17.5% of the surface area, about 50g, 120-80 mesh high refractive index glass microspheres are evenly spread on the surface, and embedded into the mixed top coating to a depth of 1 / 2 (see the attached figure and description. During the actual scraping operation, the embedding depth is sufficient to be partially submerged by the resin without losing the microspheres). The coating is then scraped flat and then heat-dried to obtain a yellow non-circular cold colored sand type infrared reflective coating. The dry film thickness of this layer (referring to the protruding part of about 1 / 2) is about 100 μm, and the final total film thickness is about 1300 μm.

[0062] Example 2

[0063] The steps for preparing the infrared reflective coating according to the process formula of "non-circular cold colored sand + high refractive index glass microspheres" (Formula 1) are as follows:

[0064] (1) Preparation of primer layer: The method is the same as that in Example 1 and will not be repeated here.

[0065] (2) Preparation of infrared reflective surface coating: 60 g of silicone-modified acrylic emulsion was weighed and poured into a stirring container, 0.8 g of film-forming aid, 0.2 g of dispersant, 1.5 g of thickener, 0.2 g of curing agent, and 0.15 g of defoamer were added, and stirred at 500-1200 rpm for 30 minutes to prepare a base material for the surface coating; 200 g of 120-80 mesh blue non-circular cold-colored sand and 200 g of 120-80 mesh high-refractive index glass microspheres were added to the base material, and mixed evenly to prepare a surface coating composed of 50% blue non-circular cold-colored sand and 50% high-refractive index glass microspheres;

[0066] (3) Preparation of high refractive index transparent mid-coat paint: The method is the same as in Example 1 and will not be repeated here.

[0067] (4) The method is the same as in Example 1 and will not be repeated here.

[0068] (5) Before the top coating of step (4) is cured, 17.5% of the surface area, about 50g, 120-80 mesh high refractive index glass microspheres are evenly spread on the surface, and embedded into the mixed top coating to a depth of 1 / 2 (see the attached figure and description. During the actual scraping operation, the embedding depth is sufficient to be partially submerged by the resin without losing the microspheres). The coating is scraped flat, and then heat-dried to obtain a blue non-circular cold-colored sand-type infrared reflective coating. The dry film thickness of this layer (referring to the protruding part of about 1 / 2) is about 150μm, and the final total film thickness is about 1300μm.

[0069] Example 3

[0070] The steps for preparing the infrared reflective coating according to the process formula of "non-circular cold colored sand + high refractive index glass microspheres" (Formula 1) are as follows:

[0071] (1) Preparation of primer layer: The method is the same as that in Example 1 and will not be repeated here.

[0072] (2) Preparation of infrared reflective surface coating: 100 g of silicone-modified acrylic emulsion was weighed and poured into a stirring container, 1.0 g of film-forming aid, 0.4 g of dispersant, 3 g of thickener, 0.3 g of curing agent, and 0.2 g of defoamer were added, and stirred at 500-1200 rpm for 30 minutes to prepare a base material for the surface coating; 300 g of 120-80 mesh yellow non-circular cold-colored sand and 300 g of 120-80 mesh high-refractive index glass microspheres were added to the base material, and mixed evenly to prepare a surface coating composed of 50% yellow non-circular cold-colored sand and 50% high-refractive index glass microspheres;

[0073] (3) Preparation of high refractive index transparent mid-coat paint: The method is the same as in Example 1 and will not be repeated here.

[0074] (4) The method is the same as in Example 1 and will not be repeated here.

[0075] (5) Before the top coating of step (4) is cured, 25% of the surface area, about 100g, 120-80 mesh high refractive index glass microspheres are evenly spread on the surface, and embedded into the mixed top coating to a depth of 1 / 2 (see the attached figure and description. During the actual scraping operation, the embedding depth is sufficient to be partially submerged by the resin without losing the microspheres). The surface is scraped flat, and then the surface is kept warm and dried to obtain a yellow non-circular cold colored sand type infrared reflective coating. The surface dry film thickness of this layer (referring to the protruding part of about 1 / 2) is about 150μm, and the final total film thickness is about 1300μm.

[0076] Example 4

[0077] The steps for preparing the infrared reflective coating according to the process formula of "non-circular cold colored sand + high refractive index glass microspheres" (Formula 1) are as follows:

[0078] (1) Preparation of primer layer: The method is the same as that in Example 1 and will not be repeated here.

[0079] (2) Preparation of infrared reflective surface coating: 100 g of silicone-modified acrylic emulsion was weighed and poured into a stirring container, 1.0 g of film-forming aid, 0.4 g of dispersant, 3 g of thickener, 0.3 g of curing agent, and 0.2 g of defoamer were added, and stirred at 500-1200 rpm for 30 minutes to prepare a base material for the surface coating; 300 g of 120-80 mesh blue non-circular cold-colored sand and 300 g of 120-80 mesh high-refractive index glass microspheres were added to the base material, and mixed evenly to prepare a surface coating composed of 50% blue non-circular cold-colored sand and 50% high-refractive index glass microspheres;

[0080] (3) Preparation of high refractive index transparent mid-coat paint: The method is the same as in Example 1 and will not be repeated here.

[0081] (4) The method is the same as in Example 1 and will not be repeated here.

[0082] (5) Before the top coating of step (4) is cured, 25% of the surface area, about 100g, 120-80 mesh high refractive index glass microspheres are evenly spread on the surface, and embedded into the mixed top coating to a depth of 1 / 2 (see the attached figure and description. During the actual scraping operation, the embedding depth is sufficient to be partially submerged by the resin without losing the microspheres). The coating is then scraped flat and then heat-dried to obtain a blue non-circular cold-colored sand-type infrared reflective coating. The dry film thickness of this layer (referring to the protruding part of about 1 / 2) is about 150μm, and the final total film thickness is about 1300μm.

[0083] Example 5

[0084] The steps for preparing infrared reflective heat-insulating coating according to the process formula of "infrared reflective microspheres + high refractive index glass microspheres" (Formula 2) are as follows:

[0085] (1) Preparation of primer layer: The method is the same as that in Example 1 and will not be repeated here.

[0086] (2) Preparation of infrared reflective surface coating: 60 g of silicone-modified acrylic emulsion was weighed and poured into a stirring container, 0.8 g of film-forming aid, 0.2 g of dispersant, 1.5 g of thickener, 0.2 g of curing agent, and 0.15 g of defoamer were added, and stirred at 500-1200 rpm for 30 minutes to prepare a base material for the surface coating; 200 g of 120-80 mesh yellow infrared reflective microspheres and 200 g of 120-80 mesh high refractive index glass microspheres were added to the base material, and mixed evenly to prepare a surface coating composed of 50% yellow infrared reflective microspheres and 50% high refractive index glass microspheres;

[0087] (3) Preparation of high refractive index transparent mid-coat paint: The method is the same as in Example 1 and will not be repeated here.

[0088] (4) First, the high-refractive and retro-transparent middle coating obtained in step (3) is evenly scraped on an aluminum plate coated with ordinary titanium dioxide and reflective titanium dioxide primer, with a size of 100×80×1.0 mm; after the coating is surface-dried (the film thickness of this layer after surface drying is about 700 μm), the mixed top coating obtained in step (2) is evenly scraped on the high-refractive and retro-transparent middle coating, and the film thickness of this layer after surface drying is about 250 μm;

[0089] (5) Before the mixed surface coating in step (4) is cured, 17.5% of the surface area, about 50g, 120-80 mesh high refractive index glass microspheres are evenly spread on the surface, and embedded into the mixed surface coating to a depth of 1 / 2 (see the attached figure and description. During the actual scraping operation, the embedding depth is sufficient to be partially submerged by the resin without losing the microspheres). The mixture is scraped flat, and then heat-dried to obtain a yellow microsphere type infrared reflective coating. The dry film thickness of this layer (referring to the protruding part of about 1 / 2) is about 100μm, and the final total film thickness is about 1000μm.

[0090] Example 6

[0091] The steps for preparing infrared reflective heat-insulating coating according to the process formula of "infrared reflective microspheres + high refractive index glass microspheres" (Formula 2) are as follows:

[0092] (1) Preparation of primer layer: The method is the same as that in Example 1 and will not be repeated here.

[0093] (2) Preparation of infrared reflective surface coating: 60 g of silicone-modified acrylic emulsion was weighed and poured into a stirring container, 0.8 g of film-forming aid, 0.2 g of dispersant, 1.5 g of thickener, 0.2 g of curing agent, and 0.15 g of defoamer were added, and stirred at 500-1200 rpm for 30 minutes to prepare a base material for the surface coating; 200 g of 120-80 mesh blue infrared reflective microspheres and 200 g of 120-80 mesh high refractive index glass microspheres were added to the base material, and mixed evenly to prepare a surface coating composed of 50% blue infrared reflective microspheres and 50% high refractive index glass microspheres;

[0094] (3) Preparation of high refractive index transparent mid-coat paint: The method is the same as in Example 1 and will not be repeated here.

[0095] (4) The method is the same as in Example 5 and will not be repeated here.

[0096] (5) Before the mixed surface coating in step (4) is cured, 17.5% of the surface area, about 50g, 120-80 mesh high refractive index glass microspheres are evenly spread on the surface, and embedded into the mixed surface coating to a depth of 1 / 2 (see the attached figure and description. During the actual scraping operation, the embedding depth is sufficient to be partially submerged by the resin without losing the microspheres). The mixture is scraped flat, and then heat-dried to obtain a blue microsphere type infrared reflective coating. The dry film thickness of this layer (referring to the protruding part of about 1 / 2) is about 100μm, and the final total film thickness is about 1000μm.

[0097] Example 7

[0098] The steps for preparing infrared reflective heat-insulating coating according to the process formula of "infrared reflective microspheres + high refractive index glass microspheres" (Formula 2) are as follows:

[0099] (1) Preparation of primer layer: The method is the same as that in Example 1 and will not be repeated here.

[0100] (2) Preparation of infrared reflective surface coating: The method is the same as that of Example 5 and will not be repeated here.

[0101] (3) Preparation of high refractive index transparent mid-coat paint: The method is the same as in Example 1 and will not be repeated here.

[0102] (4) The method is the same as in Example 5 and will not be repeated here.

[0103] (5) Before the mixed surface coating in step (4) is cured, 25% of the surface area, about 100g, 120-80 mesh high refractive index glass microspheres are evenly spread on the surface, and embedded into the mixed surface coating to a depth of 1 / 2 (see the attached figure and description. During the actual scraping operation, the embedding depth is sufficient to be partially submerged by the resin without losing the microspheres). The mixture is scraped flat, and then heat-dried to obtain a yellow microsphere type infrared reflective coating. The dry film thickness of this layer (referring to the protruding part of about 1 / 2) is about 100μm, and the final total film thickness is about 1000μm.

[0104] Example 8

[0105] The steps for preparing infrared reflective heat-insulating coating according to the process formula of "infrared reflective microspheres + high refractive index glass microspheres" (Formula 2) are as follows:

[0106] (1) Preparation of primer layer: The method is the same as that in Example 1 and will not be repeated here.

[0107] (2) Preparation of infrared reflective surface coating: The method is the same as that of Example 6 and will not be repeated here.

[0108] (3) Preparation of high refractive index transparent mid-coat paint: The method is the same as in Example 1 and will not be repeated here.

[0109] (4) The method is the same as in Example 6 and will not be repeated here.

[0110] (5) Before the mixed surface coating in step (4) is cured, 25% of the surface area, about 100g, 120-80 mesh high refractive index glass microspheres are evenly spread on the surface, and embedded into the mixed surface coating to a depth of 1 / 2 (see the attached figure and description. During the actual scraping operation, the embedding depth is sufficient to be partially submerged by the resin without losing the microspheres). The mixture is scraped flat, and then heat-dried to obtain a blue microsphere type infrared reflective coating. The dry film thickness of this layer (referring to the protruding part of about 1 / 2) is about 100μm, and the final total film thickness is about 1000μm.

[0111] Performance Test:

[0112] The coatings prepared in the above examples were tested for performance, and the results are shown in Table 1.

[0113]

[0114] By testing and comparing the performance of <Example 1-8> and <Cold Colored Sand Application Case 1-2> (Table 1), the following conclusions can be drawn:

[0115] High refractive index glass microspheres have a significant effect of improving the brightness of the "non-circular cold colored sand" coating. For high-brightness yellow, the maximum increase is 7.16 degrees, and for low-brightness blue, the maximum increase is 13.97 degrees;

[0116] "Non-circular cold colored sand" improves the brightness of the coating while keeping the infrared reflective pigment performance constant, and also correspondingly improves the total solar reflectance (TSR) of the coating;

[0117] By using high-refractive-index glass microspheres, the hemispherical emissivity of the coating is also increased to a certain extent;

[0118] Compared with "non-circular cold colored sand + high refractive index glass microspheres" (formula 1), "infrared reflective microspheres + high refractive index glass microspheres" (formula 2) has a more obvious brightness improvement, and its principle is also easy to understand, so I will not elaborate on it here;

[0119] Different mixing ratios of "high refractive index glass microspheres" and "infrared reflective microspheres" have different effects on the TSR and NIR performance improvement of high-brightness pigments and low-brightness pigments. Generally, the ratio of high refractive index glass microspheres: infrared reflective microspheres = 1:1, and when high refractive index glass microspheres with a surface area of ​​17.5%-25% are embedded in the topcoat, the improvement of low-brightness colors is greater than that of high-brightness colors. The principle is also easy to understand, so I will not go into details here;

[0120] In short, the coating with high refractive index glass microspheres has the characteristics of strong emission, high refraction and retro-reflection. It can improve the brightness of "non-circular cold colored sand" coatings. With the use of infrared reflective microspheres, it can greatly improve the hemispherical emissivity (HE), total solar reflectivity (TSR) and near infrared reflectivity (NIR) of infrared reflective coatings, especially real stone paint texture coatings.

[0121] High refractive index glass microspheres can be used not only in the field of infrared reflective coatings, but also in other coating fields that require pigments or coating brightness. Any changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principle of the present invention shall be equivalent replacement methods and shall be included in the protection scope of the present invention.

Claims

1. An application of high refractive index glass microspheres, characterized in that: By adding high refractive index glass microspheres to the infrared reflective coating, the brightness and infrared reflective performance of the coating are improved; The infrared reflective coating comprises a base coat, a middle coat and a top coat in order from bottom to top; the middle coat is entirely made of a mixture of high-refractive index glass microspheres and a base material, the top coat base material is added with high-refractive index glass microspheres and non-circular cold colored sand or infrared reflective microspheres in a mass ratio of 1:1, and 15%-25% of the coating area of ​​the top coat is embedded with high-refractive index glass microspheres; The high refractive index glass microspheres are transparent optical microspheres with a refractive index greater than √2; The particle size of the high refractive index glass microspheres used is any single narrow particle size of 0 to 4000 μm and / or a wide particle size group composed of a physical mixture of multiple particle sizes, and the particle size is not zero.

2. The use of a high refractive index glass microsphere according to claim 1, characterized in that: The adopted high refractive index glass microspheres have a particle size of 10-1000 μm and any single narrow particle size and / or a wide particle size group composed of a physical mixture of multiple particle sizes.

3. The use of a high refractive index glass microsphere according to claim 1, characterized in that: The high refractive index glass microspheres refer to transparent optical microspheres with a refractive index of 1.93±0.

005.

4. The use of a high refractive index glass microsphere according to claim 1, characterized in that: The high refractive index glass microspheres refer to high refractive index glass microspheres of TiO2-BaO-SiO2-Al2O3 or BaO-SiO2-TiO2, with the number of microspheres visually detected being no less than 150 within a field of view of a 20-40 times optical microscope, the total number of defective microspheres being less than 5% of the total number of statistics, the roundness being ≥95%, the devitrification being <3%, and the specific gravity being 4.2±0.1 g / cm3; defective microspheres refer to glass microspheres with defects, crystallization, debris, impurities, bubbles, and stripes.

5. An infrared reflective coating obtained by the application of any one of claims 1 to 4, characterized in that: The structure comprises an aluminum plate, a base coating, a middle coating, a top coating which are sequentially coated and cured, and high-refractive-index glass microspheres embedded in the top coating; The coating of the base coating layer comprises a base material for the base coating layer, ordinary titanium dioxide and reflective titanium dioxide, and the base coating layer has a film thickness of 40-100 μm; The coating material of the middle coating layer comprises a base material for the middle coating layer and high-refractive index glass microspheres, and the film thickness of the middle coating layer is 400-600 μm; The coating material of the surface coating layer comprises a base material for the surface coating layer, high-refractive index glass microspheres and non-circular cold colored sand or infrared reflective microspheres, and the film thickness of the surface coating layer is 400-500 μm; The dry thickness of the protruding part of the surface coating is 50-200μm; The high-refractive index glass microspheres embedded in the surface coating layer account for 15%-25% of the coating area of ​​the surface coating layer, and the embedding depth of the high-refractive index glass microspheres is 1 / 3 to 1 / 2 of the particle size thereof.

6. An infrared reflective coating according to claim 5, characterized in that: The base materials for each coating are independently selected to have the following composition in the following mass parts: composition: The mass fraction of ordinary titanium dioxide in the primer coating is 1-50, and the mass fraction of reflective titanium dioxide is 2-100, which is consistent with the mass fraction in the base material for the primer coating; The non-circular cold colored sand or infrared reflective microspheres in the coating of the top coating are 100-800 parts by mass, and the high refractive index glass microspheres are 100-800 parts by mass, which are consistent with the mass fractions in the base material for the top coating; The mass fraction of the high refractive index glass microspheres in the coating of the middle coating is 100-800, which is consistent with the mass fraction standard in the base material for the middle coating.

7. An infrared reflective coating according to claim 6, characterized in that: The non-circular cold colored sand is prepared by using non-circular irregular siliceous sand or calcareous sand mineral particles with a particle size greater than 200 meshes, coating the outer surface of the particles with infrared reflective pigments and organic / inorganic adhesives, and using a high-temperature sintering method / chemical cross-linking method to prepare the non-circular infrared reflective colored sand; The infrared reflective microspheres are prepared by using transparent, spherical silicate glass microspheres with a particle size of less than 4000 μm as a base material, and wrapping the outer surface of the glass microspheres with infrared reflective pigments and organic / inorganic adhesives, and using a high-temperature sintering method / chemical cross-linking method; The particle size of the non-circular cold colored sand is selected from one of 200-120 mesh, 120-80 mesh, and 80-40 mesh. Corresponding to the particle size selection of the non-circular cold colored sand, the particle size of the infrared reflective microspheres is selected from one of 160 mesh, 100 mesh, and 60 mesh.

8. An infrared reflective coating according to claim 7, characterized in that: When non-circular cold colored sand is used in the top coating, the particle size of the high refractive index glass microspheres used in the middle coating is selected from one of 200-120 mesh, 120-80 mesh, and 80-40 mesh, the particle size of the high refractive index glass microspheres embedded in the top coating is selected from one of 200-120 mesh, 120-80 mesh, and 80-40 mesh, and the final total thickness of the infrared reflective coating is 1000-1500 μm; When infrared reflective microspheres are used in the top coating, the particle size of the high refractive index glass microspheres used in the middle coating is selected from one of 160 mesh, 100 mesh, and 60 mesh, the particle size of the high refractive index glass microspheres embedded in the top coating is selected from one of 160 mesh, 100 mesh, and 60 mesh, and the final total film thickness of the infrared reflective coating is 800-1300 μm.

9. A method for preparing the infrared reflective coating according to any one of claims 5 to 8, characterized in that: The specific steps are as follows: (1) Preparation of the primer: weigh the organosilicon-modified acrylic emulsion in the base material and pour it into a stirring container, then add other components of the base material and stir at 500-1200 rpm for 30 minutes to prepare the base material for the primer coating; then add ordinary titanium dioxide and reflective titanium dioxide to the base material, disperse and stir them evenly to prepare the primer coating; and apply the primer coating on an aluminum plate with a size of 100×80×1.0 mm, and the primer film is dried and hardened for standby use; (2) Preparation of topcoat coating: weigh the organosilicon-modified acrylic emulsion in the base material and pour it into a stirring container, then add other components of the base material and stir at 500-1200 rpm for 30 minutes to prepare the base material for the topcoat coating; then add non-circular cold colored sand or infrared reflective microspheres, high refractive index glass microspheres into the base material and mix them evenly to prepare the topcoat coating; (3) Preparation of high-refractive and retro-transparent mid-coat paint: weigh the organosilicon-modified acrylic emulsion in the base material and pour it into a stirring container, then add other components of the base material and stir at 500-1200 rpm for 30 minutes to prepare the base material for the mid-coat paint; then add high-refractive index glass microspheres into the base material and mix well to prepare the high-refractive and retro-transparent mid-coat paint; (4) firstly, the high-refractive and retro-transparent middle coating obtained in step (3) is evenly scraped on the aluminum plate coated with ordinary titanium dioxide and reflective titanium dioxide base coating in step (1), and after the coating is dried, the top coating obtained in step (2) is evenly scraped on the high-refractive and retro-transparent middle coating; (5) Before the infrared reflective surface coating in step (4) is cured, high-refractive index glass microspheres accounting for 15% to 25% of the surface coating area are evenly spread on the surface, and embedded in non-circular cold colored sand or infrared reflective microspheres, with the embedding depth of the high-refractive index glass microspheres being 1 / 3 to 1 / 2 of their particle size; then, the surface is scraped flat, and then heat-dried to obtain the infrared reflective coating.

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