An inorganic resin heat insulation coating, its preparation method and application

Abstract

The present invention belongs to the technical field of coating compositions, and provides a heat-insulating coating for inorganic resin, a preparation method and an application thereof. The heat-insulating coating comprises the following raw materials in parts by weight: 40-60 parts of modified inorganic resin, 15-25 parts of modified cesium tungsten oxide slurry, 4-8 parts of film-forming auxiliary agent, 2-6 parts of ultraviolet absorber, 0.5-1 part of bactericide, and 0.1-0.4 part of defoaming agent. The heat-insulating coating of the present invention has a low transmittance, good toughness and storage stability, and has excellent heat-insulating effect, and can be used in the field of electrostatic film laminating.

Description

Technical Field

[0001] The present invention belongs to the technical field of coating compositions, and particularly relates to a heat-insulating coating of inorganic resin, its preparation method and application. Background Art

[0002] With the continuous increase in global energy consumption, the demand for lightweight and efficient heat-insulating materials is also rising. Electrostatic film is a film that uses the principle of electrostatic adsorption to fix on the surface of an object. As a material widely used in many fields such as construction and agriculture, the optimization of its heat-insulating performance has become particularly important. Although traditional electrostatic films have good portability and flexibility, they have deficiencies in heat-insulating performance, which limits their effectiveness in specific application scenarios. Heat-insulating coatings are a new type of coatings that absorb and shield near-infrared light and ultraviolet light, which can increase the heat-insulating effect for electrostatic films, achieving the purpose of energy conservation and consumption reduction, and are of great significance. The electrostatic film coated with the heat-insulating coating of the present invention has relatively excellent heat-insulating effect, and is widely applicable to sunscreen, heat insulation and heat preservation in transparent scenarios, and can be used in fields such as construction, automobiles, greenhouses, culture and tourism.

[0003] With the progress of technology, heat-insulating coatings are developing towards a more efficient and environmentally friendly direction. Among them, inorganic resin, as a new type of polymer material, has excellent heat resistance, chemical corrosion resistance, high mechanical strength and good electrical insulation performance. In recent years, with the development of materials science, the application of inorganic resin in the field of coatings has gradually increased, especially showing great potential in the preparation of heat-insulating coatings. However, the existing inorganic resin heat-insulating coatings still have certain limitations in terms of heat-insulating performance, flexibility and storage stability.

[0004] Chinese Patent CN 110511670 A discloses a coating composition with heat-insulating and anti-fouling functions prepared from a non-easy-to-clean resin. This coating uses an easy-to-clean modification aid to solve the cleaning problem and at the same time reduces the production cost of the coating composition. In addition, since the material of polysilazane is abandoned, the problems caused by polysilazane, such as the coating being prone to embrittlement, insufficient heat-insulating performance due to too thin a coating, and slight whitening during coating, are also solved. However, the infrared barrier rate of this coating composition is still relatively low.

[0005] Therefore, there is an urgent need to develop an inorganic resin heat-insulating coating with a high infrared barrier rate, so that it has a relatively excellent heat-insulating effect when coated on an electrostatic film. Summary of the Invention

[0006] Aiming at the existing technical problems, the purpose of the present invention is to provide a heat-insulating coating of inorganic resin and its preparation method. The heat-insulating coating of the present invention has low transmittance, good toughness and storage stability, and has excellent heat-insulating effect, and is used in the field of electrostatic films.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] The present invention provides a heat-insulating coating of inorganic resin. By weight, the heat-insulating coating comprises the following raw materials: 40-60 parts of modified inorganic resin, 15-25 parts of modified cesium tungsten oxide slurry, 4-8 parts of film-forming auxiliary agent, 2-6 parts of ultraviolet absorber, 0.5-1 part of bactericide, and 0.1-0.4 part of defoamer.

[0009] The reaction mechanism and function of the present invention are as follows:

[0010] 1. Silicone-based inorganic resins usually have excellent thermal stability and can maintain their physical and chemical properties at high temperatures, making them suitable for application scenarios with high-temperature resistance requirements. However, inorganic resins have poor storage stability and are prone to problems such as precipitation, stratification, and gelation.

[0011] In the present invention, by mixing organoalkoxysilane, silica sol, and organic solvent and regulating the ratio of the three, the inorganic resin formed thereby has the effect of enhancing mechanical properties. Furthermore, by modifying the inorganic resin to introduce branched chains with polar functional groups, a charge effect can be generated, and the self-polymerization process of silica sol can be inhibited through electrostatic repulsion, improving the storage stability of silica sol. At the same time, the branched chains grafted onto the surface of silica sol that do not participate in the reaction can hinder the contact between particles due to steric hindrance before the silica sol cures, improving the stability of silica sol and thus the storage stability of the inorganic resin coating.

[0012] More importantly, silica sol has a high surface energy, and large internal stresses will be generated during the process of dehydration condensation and curing to form a film, which is likely to cause cracking of the coating. By adding a modified silicone-acrylic emulsion, its deficiencies can be made up and the film-forming performance can be improved. In addition, the modified silicone-acrylic emulsion prepared in this application not only has the characteristics of pure acrylic emulsion but also improves the hardness, abrasion resistance, tensile strength, water resistance, acid and alkali resistance, and weather resistance of the heat-insulating coating.

[0013] 2. Cesium tungsten oxide nanometer powder has a high specific surface area and surface energy, making it difficult to be evenly dispersed in inorganic resin. If the dispersion is uneven, voids may appear at the interface of the resin material, which will increase the chance of water entering the voids, and the infiltration of water will cause the resin material to gradually decompose and become brittle, resulting in a decline in performance.

[0014] In the present invention, a specific amount of sorbitol is selected to modify cesium tungsten oxide nano-powder, which can improve the dispersibility and stability of the cesium tungsten oxide nano-powder and enhance the heat insulation performance of the resin. Further, polyvinylpyrrolidone is introduced to prevent further aggregation of nano-particles, thereby obtaining a more uniform heat insulation coating; at the same time, polyvinylpyrrolidone can improve the rheological properties of the heat insulation coating, making the coating have better coating performance during construction, facilitating the formation of a uniform coating film, and further improving the overall adhesion, hardness, water resistance and heat insulation of the coating.

[0015] In addition, cesium tungsten oxide nano-powder has a strong blocking effect on infrared rays, but its price is relatively high; antimony tin oxide nano-powder has a narrow shielding range in the infrared band, but its price is low. In this application, the mass ratio of the modified cesium tungsten oxide nano-powder and antimony tin oxide nano-powder is regulated through research, so that the raw material usage cost is relatively low under the condition that the infrared ray blocking rate and the visible light transmittance are not affected.

[0016] In some embodiments, the preparation method of the modified inorganic resin comprises the following steps:

[0017] (1) Mix an organic alkoxysilane, an organic solvent and a silica sol, heat to 40-50 °C, stir and react for 30-60 min, and evacuate to obtain an inorganic resin;

[0018] (2) Add the silica sol and an organic acid into a reaction kettle, heat to 65-80 °C, keep warm and react for 1-1.5 h, add the mixture of the inorganic resin and deionized water obtained in step (1), and continue to keep warm and react for 1-2 h; when the reaction kettle cools down to 50-60 °C, dropwise add a silane coupling agent while stirring, then keep warm and react for 1.5-2.5 h, cool, and then add a modified silicone-acrylic emulsion and stir for 1-2 h to obtain a modified inorganic resin.

[0019] In some embodiments, the mass ratio of the organic alkoxysilane to the silica sol in step (1) is 1:(0.5-0.7).

[0020] In some embodiments, the mass ratio of the silica sol, the inorganic resin and the modified silicone-acrylic emulsion in step (2) is (1.8-2.6):1:(0.5-0.65).

[0021] In some embodiments, the preparation method of the modified silicone-acrylic emulsion comprises the following steps:

[0022] A1. Mix methyl methacrylate, butyl acrylate and acrylic acid to obtain mixture 1; mix methyl methacrylate, butyl acrylate, acrylic acid and vinyl silicone oil to obtain mixture 2;

[0023] A2. Mix sodium dodecyl sulfate, nonylphenol polyoxyethylene ether OP-10, deionized water, and ammonia water, heat the mixture to 75 - 85 °C with stirring, add potassium persulfate, dropwise add the mixture 1 obtained in step A1, control the dropping time within 1.5 - 2.5 h, keep the temperature for reaction for 0.5 - 1 h, then dropwise add the mixture 2 obtained in step A1, control the dropping time within 2 - 2.5 h, and then keep the temperature for reaction for 2 - 3 h. Cool down, filter and discharge to obtain the modified silicone-acrylic emulsion.

[0024] Preferably, in the mixture 1 in step A1, the mass ratio of methyl methacrylate, butyl acrylate, and acrylic acid is 1:1:(0.4 - 0.6); in the mixture 2, the mass ratio of methyl methacrylate, butyl acrylate, acrylic acid, and vinyl silicone oil is 1:1:(0.4 - 0.6):(0.4 - 0.6).

[0025] Preferably, in step A2, the mass ratio of sodium dodecyl sulfate, nonylphenol polyoxyethylene ether OP-10, deionized water, and 20wt% - 28wt% ammonia water is 1:(1 - 2):(15 - 20):(0.05 - 0.15).

[0026] Preferably, the addition amount of potassium persulfate in step A2 is 1.2 - 2.5% of the total mass of sodium dodecyl sulfate, nonylphenol polyoxyethylene ether OP-10, deionized water, and ammonia water.

[0027] In some embodiments, the preparation method of the modified cesium tungsten oxide nano-slurry comprises the following steps:

[0028] S1. Add cesium tungsten oxide nano-powder, deionized water, sorbitol, and sodium hydroxide into a reaction kettle, stir, ball-mill and disperse, and dry to obtain modified cesium tungsten oxide nano-powder;

[0029] S2. Mix and ball-mill the modified cesium tungsten oxide nano-powder obtained in step S1, antimony tin oxide nano-powder, and deionized water, add polyvinylpyrrolidone, stir for 1 - 2 h, and ultrasonicate for 20 - 30 min to obtain the modified cesium tungsten oxide nano-slurry.

[0030] In some embodiments, the mass ratio of the cesium tungsten oxide nano-powder and sorbitol in step S1 is 1:(0.05 - 0.1).

[0031] In some embodiments, the mass ratio of the modified cesium tungsten oxide nano-powder, antimony tin oxide nano-powder, and polyvinylpyrrolidone in step S2 is 1:(0.4 - 0.6):(0.05 - 0.15).

[0032] In some embodiments, the film-forming auxiliary is any one or more of trimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, 3-aminopropyltrimethoxysilane, and 3-aminopropyltriethoxysilane.

[0033] Preferably, the film-forming auxiliary is 3-aminopropyltrimethoxysilane and / or 3-aminopropyltriethoxysilane.

[0034] Preferably, the particle size of the cesium tungsten oxide powder is 35 - 55 nm.

[0035] In some embodiments, the defoamer is a silicone defoamer.

[0036] The second aspect of the present invention provides a method for preparing a heat-insulating coating of an inorganic resin, comprising the following steps:

[0037] Mechanically blend the modified inorganic resin, the modified cesium tungsten oxide slurry, the film-forming auxiliary, the ultraviolet absorber, the bactericide, and the defoamer to obtain the heat-insulating coating.

[0038] The third aspect of the present invention provides an application of the heat-insulating coating of an inorganic resin in the field of electrostatic films. The method for preparing the electrostatic film comprises the following steps:

[0039] I. Use a coater to coat the heat-insulating coating on the upper surface of the substrate layer, adjust the thickness, and dry to obtain a heat-insulating coating layer;

[0040] II. Apply corona to the substrate layer with the heat-insulating coating layer obtained in step I to obtain the electrostatic film.

[0041] Preferably, the substrate layer of the electrostatic film is a PET substrate layer or a PP substrate layer.

[0042] More preferably, the PP substrate layer comprises at least two layers: one is an insulating layer for preventing electrostatic leakage; one is a base layer for carrying static electricity.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0044] 1. The heat-insulating coating of the present invention has a low transmittance, good toughness and storage stability, and has excellent heat-insulating effects, and can be used in the field of electrostatic films.

[0045] 2. The modified inorganic resin of the present invention has good storage stability and excellent film-forming performance. The introduced modified silicone-acrylic emulsion not only makes up for the problem of coating cracking that may be caused by internal stress of silica sol, but also improves the hardness, wear resistance, tensile strength, water resistance, acid and alkali resistance, and weather resistance of the heat-insulating coating.

[0046] 3. The present invention modifies cesium tungsten oxide nanoparticles by selecting specific sorbitol and polyvinylpyrrolidone, enabling them to be stable and uniformly dispersed in inorganic resins, thereby improving the overall performance of the heat-insulating coating. Meanwhile, the present application has studied and regulated the mass ratio of the compounding of modified cesium tungsten oxide nanoparticles and antimony tin oxide nanoparticles, so that the raw material usage cost is relatively low while the infrared blocking rate and visible light transmittance are not affected. Detailed implementation manners

[0047] The present invention will be described below in conjunction with specific implementation manners. It should be noted that the following examples are examples of the present invention, only for explaining the present invention, rather than limiting the present invention. Without departing from the gist or scope of the present invention, other combinations and various improvements within the concept of the present invention can be made.

[0048] According to the mixing ratios and production methods of the various raw materials specified in the following examples and comparative examples, various heat-insulating coatings are produced.

[0049] For the convenience of those skilled in the art to implement the present invention, the manufacturers of some raw materials in the examples and comparative examples are described as follows:

[0050] Cesium tungsten oxide nanoparticles: purchased from Hangzhou Jikang New Materials Co., Ltd., with a particle size of 40 nm;

[0051] Organosilicon defoamer: purchased from Hunan Jiaxinzhi New Materials Technology Co., Ltd., model BYK-141;

[0052] Poly(diallyldimethylammonium chloride): purchased from Jinan Zhendong Chemical Co., Ltd.;

[0053] For other raw materials, without special instructions, they can all be purchased from the market.

[0054] Preparation Example 1

[0055] The preparation method of modified silicone-acrylic emulsion A includes the following steps:

[0056] A1. Mix 20 g of methyl methacrylate, 20 g of butyl acrylate, and 10 g of acrylic acid to obtain mixture 1; mix 20 g of methyl methacrylate, 20 g of butyl acrylate, 10 g of acrylic acid, and 10 g of vinyltriethoxysilane to obtain mixture 2;

[0057] A2. Mix 1.4 g of sodium dodecyl sulfate, 2.1 g of nonylphenol polyoxyethylene ether OP-10, 25.2 g of deionized water, and 0.14 g of 25 wt% ammonia water. While stirring, heat the mixture to 80 °C, add 0.6 g of potassium persulfate, and then dropwise add the mixture 1 obtained in step A1, controlling the dropping time within 2 h. Keep the temperature for reaction for 45 min, then dropwise add the mixture 2 obtained in step A1, controlling the dropping time within 2.5 h, and then keep the temperature for reaction for 2.5 h. Cool to room temperature, filter and discharge to obtain the modified silicone-acrylic emulsion A.

[0058] Preparation Example 2

[0059] The preparation method of the modified silicone-acrylic emulsion B is the same as that of Preparation Example 1, except that the addition amount of vinyltriethoxysilane in step A1 is 6 g.

[0060] Preparation Example 3

[0061] The preparation method of the modified inorganic resin A includes the following steps:

[0062] (1) Mix 10 g of methyltriethoxysilane, 4 g of ethanol, 2 g of isopropanol, and 6 g of silica sol, heat to 50 °C, stir and react for 45 min, and evacuate for 5 min to obtain the inorganic resin;

[0063] (2) Add 11 g of silica sol and 2 g of tartaric acid to the reaction kettle, heat to 75 °C, keep the temperature for reaction for 1 h, add the mixture of 5 g of the inorganic resin obtained in step (1) and 4 g of deionized water, and continue to keep the temperature for reaction for 2 h; when the temperature of the reaction kettle drops to 55 °C, while stirring, dropwise add 1 g of silane coupling agent KH-560, then keep the temperature for reaction for 2 h, cool to room temperature, and then add 3 g of the modified silicone-acrylic emulsion A and stir for 1.5 h to obtain the modified inorganic resin A.

[0064] Preparation Example 4

[0065] The preparation method of the modified inorganic resin B is the same as that of Preparation Example 3, except that the addition amount of silica sol in step (1) is 4 g.

[0066] Preparation Example 5

[0067] The preparation method of the modified inorganic resin C is the same as that of Preparation Example 3, except that the addition amount of the modified silicone-acrylic emulsion A in step (1) is 2 g.

[0068] Preparation Example 6

[0069] The preparation method of the modified inorganic resin D is the same as that of Preparation Example 3, except that the modified silicone-acrylic emulsion B is used to replace the modified silicone-acrylic emulsion A in step (2).

[0070] Preparation Example 7

[0071] The preparation method of the modified inorganic resin E includes the following steps:

[0072] (1) Mix 10 g of methyltriethoxysilane, 4 g of ethanol, 2 g of isopropanol, and 6 g of silica sol, heat to 50 °C, stir and react for 45 min, and evacuate for 5 min to obtain an inorganic resin;

[0073] (2) Add 11 g of silica sol and 2 g of tartaric acid to the reaction kettle, heat to 75 °C, keep warm and react for 1 h, add a mixture of 5 g of the inorganic resin obtained in step (1) and 4 g of deionized water, and continue to keep warm and react for 2 h; wait for the reaction kettle to cool down to 55 °C, dropwise add 1 g of silane coupling agent KH-560 while stirring, then keep warm and react for 2 h, and cool to room temperature to obtain modified inorganic resin E.

[0074] Preparation Example 8

[0075] A preparation method of modified cesium tungsten oxide nano-slurry A, comprising the following steps:

[0076] S1. Add 10 g of cesium tungsten oxide nano-powder, 20 g of deionized water, 0.8 g of sorbitol, and 0.2 g of 20 wt% sodium hydroxide aqueous solution to the reaction kettle, stir for 30 min, ball mill and disperse for 1 h, and dry at 60 °C for 4 h to obtain modified cesium tungsten oxide nano-powder;

[0077] S2. Mix 6 g of the modified cesium tungsten oxide nano-powder obtained in step S1, 3 g of antimony tin oxide nano-powder, and 20 g of deionized water, ball mill for 3 h, add 0.72 g of polyvinylpyrrolidone, stir for 1.5 h, and ultrasonicate for 30 min to obtain modified cesium tungsten oxide nano-slurry A.

[0078] Preparation Example 9

[0079] The preparation method of modified cesium tungsten oxide nano-slurry B is the same as that of Preparation Example 1, except that the addition amount of sorbitol is 1.2 g.

[0080] Preparation Example 10

[0081] A preparation method of modified cesium tungsten oxide nano-slurry C, comprising the following steps:

[0082] S1. Add 10 g of cesium tungsten oxide nano-powder, 20 g of deionized water, 0.8 g of sorbitol, and 0.2 g of 20 wt% sodium hydroxide aqueous solution to the reaction kettle, stir for 30 min, ball mill and disperse for 1 h, and dry at 60 °C for 4 h to obtain modified cesium tungsten oxide nano-powder;

[0083] S2. Mix 6 g of the modified cesium tungsten oxide nano-powder obtained in step S1 and 20 g of deionized water, ball mill for 3 h, add 0.72 g of polyvinylpyrrolidone, stir for 1.5 h, and ultrasonicate for 30 min to obtain modified cesium tungsten oxide nano-slurry C.

[0084] Example 1

[0085] An inorganic resin heat-insulating coating, by weight, contains the following raw materials: 50 parts of modified inorganic resin A, 20 parts of modified cesium tungsten oxide slurry A, 6 parts of 3-aminopropyltrimethoxysilane, 4 parts of 2,4-dihydroxybenzophenone, 0.75 part of polydiallyldimethylammonium chloride, and 0.25 part of silicone defoamer BYK-141.

[0086] The preparation method of the heat-insulating coating in this example includes the following steps:

[0087] Mechanically blend modified inorganic resin A, modified cesium tungsten oxide slurry A, 3-aminopropyltrimethoxysilane, 2,4-dihydroxybenzophenone, polydiallyldimethylammonium chloride, and silicone defoamer BYK-141 to obtain the heat-insulating coating.

[0088] Example 2

[0089] An inorganic resin heat-insulating coating, by weight, contains the following raw materials: 40 parts of modified inorganic resin A, 15 parts of modified cesium tungsten oxide slurry A, 4 parts of 3-aminopropyltrimethoxysilane, 2 parts of 2,4-dihydroxybenzophenone, 0.5 part of polydiallyldimethylammonium chloride, and 0.1 part of silicone defoamer BYK-141.

[0090] The preparation method of the heat-insulating coating in this example is the same as that in Example 1.

[0091] Example 3

[0092] An inorganic resin heat-insulating coating, by weight, contains the following raw materials: 60 parts of modified inorganic resin A, 25 parts of modified cesium tungsten oxide slurry A, 8 parts of 3-aminopropyltriethoxysilane, 6 parts of 2,4-dihydroxybenzophenone, 1 part of polydiallyldimethylammonium chloride, and 0.4 part of silicone defoamer BYK-141.

[0093] The preparation method of the heat-insulating coating in this example is the same as that in Example 1.

[0094] Example 4

[0095] An inorganic resin heat-insulating coating and its preparation method, the specific implementation method is the same as that in Example 1, except that an equal amount of modified inorganic resin B is used to replace modified inorganic resin A.

[0096] Example 5

[0097] An inorganic resin heat-insulating coating and its preparation method, the specific implementation method is the same as that in Example 1, except that an equal amount of modified inorganic resin C is used to replace modified inorganic resin A.

[0098] Example 6

[0099] An inorganic resin heat-insulating coating and its preparation method. The specific implementation method is the same as that of Example 1, except that an equal amount of modified inorganic resin D is used to replace modified inorganic resin A.

[0100] Example 7

[0101] An inorganic resin heat-insulating coating and its preparation method. The specific implementation method is the same as that of Example 1, except that an equal amount of modified inorganic resin E is used to replace modified inorganic resin A.

[0102] Example 8

[0103] An inorganic resin heat-insulating coating and its preparation method. The specific implementation method is the same as that of Example 1, except that an equal amount of modified cesium tungsten oxide slurry B is used to replace modified cesium tungsten oxide slurry A.

[0104] Example 9

[0105] An inorganic resin heat-insulating coating and its preparation method. The specific implementation method is the same as that of Example 1, except that an equal amount of modified cesium tungsten oxide slurry C is used to replace modified cesium tungsten oxide slurry A.

[0106] Comparative Example 1

[0107] An inorganic resin heat-insulating coating and its preparation method. The specific implementation method is the same as that of Example 1, except that an equal amount of commercially available potassium silicate is used to replace modified inorganic resin A.

[0108] Comparative Example 2

[0109] An inorganic resin heat-insulating coating and its preparation method. The specific implementation method is the same as that of Example 1, except that an equal amount of commercially available cesium tungsten oxide nano-powder is used to replace modified cesium tungsten oxide slurry A.

[0110] Effect evaluation:

[0111] The heat-insulating coatings prepared in the above Examples 1-9 and Comparative Examples 1-2 were tested and analyzed. The specific results are shown in Table 1.

[0112] Performance test:

[0113] (1) Brush the sample on the electrostatic film. After curing at 60 °C for 2 h, make the dry film coating thickness 6 μm, and use an LS182 optical transmittance measuring instrument to test the infrared barrier rate and visible light transmittance of the electrostatic film coating;

[0114] (2) According to the standard JG / T26-2002, test the thermal storage stability for 30 days. The coating is qualified if there is no caking, agglomeration, or mildew.

[0115] Table 1

[0116]

[0117] From the results in Table 1, it can be seen that the heat-insulating coatings prepared in Examples 1-3 have good infrared barrier rate, visible light transmittance and thermal storage stability, thus making them have better heat-insulating effects.

[0118] Compared with Example 1, in the preparation of the modified inorganic resin in Examples 4-7 and Comparative Example 1, in Example 4, the mass ratio of organoalkoxysilane, organic solvent and silica sol was changed, and in Example 5, the mass ratio of silica sol, inorganic resin and modified silicon-acrylic emulsion was changed, which affected the uniformity of the final coating; in Example 6, the type of modified silicon-acrylic emulsion was changed, and in Example 7, no modified silicon-acrylic emulsion was added to modify the inorganic resin, which may cause the coating to crack and the toughness to become poor. In Comparative Example 1, an equal amount of commercially available potassium silicate was used to replace the modified inorganic resin A, and the dispersion stability was poor, thus affecting the infrared barrier rate, visible light transmittance and thermal storage stability.

[0119] Compared with Example 1, in the preparation of the modified cesium tungsten oxide nano-slurry in Examples 8-9 and Comparative Example 2, in Example 8, the mass ratio of cesium tungsten oxide nano-powder and sorbitol was changed, which affected the compatibility between the cesium tungsten oxide nano-powder and the resin. In Example 9, the mass ratio of modified cesium tungsten oxide nano-powder, antimony tin oxide nano-powder and polyvinylpyrrolidone was changed, which affected the infrared ray barrier rate and visible light transmittance. In Comparative Example 2, an equal amount of cesium tungsten oxide nano-powder was used to replace the modified cesium tungsten oxide nano-powder A, and the dispersion compatibility became poor, thus affecting the infrared barrier rate, visible light transmittance and thermal storage stability.

[0120] (3) Application test

[0121] The heat-insulating coatings prepared in Examples 1-3 were coated on the electrostatic film for testing. The heat-insulating coatings prepared in Examples 1-3 were coated on the upper surface of the PP substrate layer by a coater, the thickness was adjusted to 40 µm, and it was baked at 70 °C for 5 min to obtain a heat-insulating coating layer. The PP substrate layer with the heat-insulating coating layer was corona-treated to obtain an electrostatic film.

[0122] Adhesion test: In an environment with a temperature of 23 ± 2 °C and a relative humidity of 50 ± 5%, a cross cutter was used to cut 2 cm × 2 cm incisions on the coating surface, and the incisions penetrated the entire heat-insulating coating layer. A soft brush was used to gently brush along the incision direction to ensure that there were no residual fragments under the coating. A 3M610 tape was attached to the cut grid pattern to ensure that the tape was in full contact with the coating surface. After 2 min, the tape was quickly peeled off at an angle of about 60°, and the peeling situation of the coating was observed and evaluated. The results were rated according to the ASTM standard.

[0123] Through testing, it can be known that the heat-insulating coating layers prepared in Examples 1-3 only have extremely small flakes peeling off at the intersections of the incisions, the actual damage in the cross-hatch area does not exceed 5%, and the ASTM grade is not lower than 4B. It can be seen that the adhesion of the heat-insulating coating is good and it can be preferably applied to electrostatic film laminating.

[0124] The above are only the preferred embodiments of the present invention and do not impose any form of limitation on this application. Although this application is disclosed with the preferred embodiments as above, it is not intended to limit this application. Any person skilled in the art, without departing from the scope of the technical solution of this application, making some changes or modifications using the disclosed technical content above is equivalent to equivalent implementation cases. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution.

Claims

1. A thermal insulation coating of an inorganic resin, characterized in that: The thermal insulation coating comprises the following raw materials by weight: 40-60 parts of modified inorganic resin, 15-25 parts of modified cesium tungsten oxide slurry, 4-8 parts of film-forming aid, 2-6 parts of ultraviolet absorber, 0.5-1 parts of bactericide, and 0.1-0.4 parts of defoamer; The preparation method of the modified inorganic resin comprises the following steps: (1) Mixing organic alkoxysilane, organic solvent and silica sol, heating to 40-50°C, stirring for 30-60 minutes, and evacuating to obtain an inorganic resin; (2) Add silica sol and organic acid to a reaction kettle, heat to 65-80°C, keep warm for 1-1.5 hours, add the mixture of inorganic resin and deionized water obtained in step (1), and continue to keep warm for 1-2 hours; wait for the reaction kettle to cool to 50-60°C, add silane coupling agent dropwise while stirring, keep warm for 1.5-2.5 hours, cool, add modified silicone-acrylic emulsion, stir for 1-2 hours, and obtain modified inorganic resin; wherein the mass ratio of silica sol, inorganic resin and modified silicone-acrylic emulsion in step (2) is (1.8-2.6):1:(0.5-0.65); The preparation method of the modified silicone acrylic emulsion comprises the following steps: A1. Methyl methacrylate, butyl acrylate and acrylic acid were mixed to obtain a mixture 1; methyl methacrylate, butyl acrylate, acrylic acid and vinyl silicone oil were mixed to obtain a mixture 2; A2. Sodium dodecyl sulfate, nonylphenol polyoxyethylene ether OP-10, deionized water, and 20wt%-28wt% ammonia water are mixed, heated to 75-85°C while stirring, potassium persulfate is added, the mixture 1 obtained in step A1 is added dropwise, the addition time is controlled to be 1.5-2.5h, the reaction is kept warm for 0.5-1h, and the mixture 2 obtained in step A1 is added dropwise, the addition time is controlled to be 2-2.5h, the reaction is kept warm for 2-3h, the mixture is cooled, and the material is filtered to obtain a modified silicone acrylic emulsion; wherein the mass ratio of methyl methacrylate, butyl acrylate, and acrylic acid in the mixture 1 in step A1 is 1:1:(0 .4-0.6); the mass ratio of methyl methacrylate, butyl acrylate, acrylic acid and vinyl silicone oil in the mixture 2 is 1:1:(0.4-0.6):(0.4-0.6); the mass ratio of sodium dodecyl sulfate, nonylphenol polyoxyethylene ether OP-10, deionized water and 20wt%-28wt% ammonia water in step A2 is 1:(1-2):(15-20):(0.05-0.15); the amount of potassium persulfate added in step A2 is 1.2-2.5% of the total mass of sodium dodecyl sulfate, nonylphenol polyoxyethylene ether OP-10, deionized water and ammonia water; The preparation method of the modified cesium tungsten oxide nano-slurry comprises the following steps: S1. Add cesium tungsten oxide nanopowder, deionized water, sorbitol and sodium hydroxide into a reactor, stir, disperse by ball milling and dry to obtain modified cesium tungsten oxide nanopowder; S2. The modified cesium tungsten oxide nanopowder, antimony tin oxide nanopowder and deionized water obtained in step S1 are mixed and ball-milled, polyvinyl pyrrolidone is added, stirred for 1-2 hours, and ultrasonicated for 20-30 minutes to obtain a modified cesium tungsten oxide nanoslurry; wherein, the mass ratio of the modified cesium tungsten oxide nanopowder, antimony tin oxide nanopowder and polyvinyl pyrrolidone in step S2 is 1: (0.4-0.6): (0.05-0.15).

2. The inorganic resin thermal insulation coating according to claim 1, characterized in that: The mass ratio of the organic alkoxysilane to the silica sol in step (1) is 1:(0.5-0.7).

3. The inorganic resin thermal insulation coating according to claim 1, characterized in that: The mass ratio of the cesium tungsten oxide nanopowder to sorbitol in step S1 is 1:(0.05-0.1).

4. The inorganic resin thermal insulation coating according to claim 1, characterized in that: In parts by weight, the film-forming aid is any one or more of trimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane.

5. A method for preparing the inorganic resin thermal insulation coating according to any one of claims 1 to 4, characterized in that: The following steps are included: The modified inorganic resin, the modified cesium tungsten oxide slurry, the film-forming aid, the ultraviolet absorber, the bactericide and the defoamer are mechanically blended to obtain the heat-insulating coating.

6. An application of the inorganic resin thermal insulation coating according to any one of claims 1 to 4 in the field of electrostatic film application, characterized in that: The preparation method of the electrostatic film comprises the following steps:

1. Apply the thermal insulation coating to the upper surface of the substrate layer using a coating machine, adjust the thickness, and dry to obtain a thermal insulation coating layer; 2. Apply corona to the substrate layer with the thermal insulation coating layer obtained in step 1 to obtain an electrostatic film.

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